Checking a set of hypotheses

The experiment uses paired muscle microtissues from older and young donors, with the donor as the experimental unit.

Different experimental conditions. The study examined muscle biopsies from young adult men undergoing exercise, rather than paired microtissues from older and young donors with donor-level experimental allocation.

Induction and adaptation of chaperone-assisted selective autophagy CASA in response to resistance exercise in human skeletal muscle (Materials and Methods: Acute resistance exercise; Sustained resistance exercise)

A selected region of each muscle microtissue undergoes the same limited deformation.

Different experimental conditions. Cultured rat smooth muscle cells and mouse fibroblasts underwent cyclic substrate stretching at 20% amplitude and 300 mHz, rather than matched limited deformation of selected microtissue regions.

Strain-induced mechanoresponse depends on cell contractility and BAG3-mediated autophagy (Results: Stretch-induced autophagy is a time-dependent process; Materials and Methods: Cell straining)

After limited deformation of old muscle, accelerating filamin removal is hypothesized to restore force transmission only if undamaged replacement filamin is incorporated locally at the damaged load-bearing site following BAG3-dependent removal.

Not verified in the article. BAG3-dependent filamin-C release and force rescue in failing hearts support related components. Necessity of local undamaged filamin incorporation after deformation of old skeletal muscle was not tested.

Cardiomyocyte contractile impairment in heart failure results from reduced BAG3-mediated sarcomeric protein turnover (Results: Eight sarcomere proteins identified as candidates for BAG3/CASA-mediated turnover; Figure 7)

The alternative explanation is that reducing the total number of protein aggregates alone is sufficient to restore force transmission.

Not verified in the article. The study distinguished aggregate staining from ubiquitinated proteins retained in sarcomeres, but did not test whether reducing aggregate numbers alone restores force in the proposed system.

Cardiomyocyte contractile impairment in heart failure results from reduced BAG3-mediated sarcomeric protein turnover (Results: Human DCM cardiomyocytes have reduced sarcomere contractile function and impaired myofilament protein turnover; Figure 1f)

The stated biological rationale is that BAG3 linked mechanical loading to autophagic removal of damaged filamin and regulation of its synthesis in cellular and tissue models, while the role of returning new filamin to the original load-bearing site remains unestablished.

Not verified in the article. The article discusses tension-induced filamin degradation and replacement, but treats overlapping synthesis cycles as an interpretation. The cited 2013 primary study is not supplied, and direct verification of the complete degradation-and-synthesis rationale is incomplete.

Induction and adaptation of chaperone-assisted selective autophagy CASA in response to resistance exercise in human skeletal muscle (Introduction and Figure 1; Results accompanying Figure 2; References 4 and 5)

The reported investigation of chaperone-assisted selective autophagy (CASA) responses to resistance loading in human muscle does not establish that the mechanical benefit originates from local replacement.

Matches this study. Human resistance exercise responses were investigated through protein abundance, transcripts, localization and muscle damage. These experiments establish the reported response but do not identify a mechanical benefit caused by local replacement.

Induction and adaptation of chaperone-assisted selective autophagy CASA in response to resistance exercise in human skeletal muscle (Figures 2-7; Materials and Methods)

BAG3-dependent removal and local anchoring of replacement filamin are manipulated independently.

Not verified in the article. Wild-type and dominant-negative BAG3 were compared, but replacement filamin anchoring was not independently manipulated.

Strain-induced mechanoresponse depends on cell contractility and BAG3-mediated autophagy (Results: Actin reorientation in A7r5 cells is dependent on BAG3-mediated autophagy; Figure 7)

The experiment includes a nonlocal replacement control with the same mass of new protein placed outside the damaged region as in the local replacement condition.

Not verified in the article. No supplied study includes an equal-mass new-filamin control placed outside the damaged region.

The disappearance of the old labeled fraction and incorporation of the new labeled fraction are measured.

Different experimental conditions. Protein abundance and transcript levels were measured, rather than separately tracking disappearance of old labeled filamin and incorporation of new labeled filamin.

Induction and adaptation of chaperone-assisted selective autophagy CASA in response to resistance exercise in human skeletal muscle (Figure 2C-E; Materials and Methods: Immunoblotting; Transcript quantification)

The primary outcome is the fraction of transmitted force restored 48 hours after loading stops.

Different experimental conditions. Maximum force-generating capacity was assessed after four weeks of BAG3 gene therapy in mice with heart failure, rather than transmitted-force recovery 48 hours after loading stops.

Cardiomyocyte contractile impairment in heart failure results from reduced BAG3-mediated sarcomeric protein turnover (Figure 7a-c; Methods: AAV9-BAG3 overexpression mouse model; Skinned myocyte Force-Ca 2+ experiments)

Local and nonlocal replacement are compared at equal overall clearance.

Not verified in the article. No supplied experiment compares local and nonlocal replacement while holding overall clearance equal.

Local replacement is predicted to restore a greater fraction of transmitted force than nonlocal replacement, whereas equivalent force would refute the proposed spatial requirement.

Not verified in the article. Neither superiority nor equivalence of force recovery between local and nonlocal replacement was tested.

Initial injury is controlled when comparing experimental conditions.

Not verified in the article. Creatine kinase and structural damage were assessed, but initial injury was not matched across local and nonlocal replacement conditions.

Induction and adaptation of chaperone-assisted selective autophagy CASA in response to resistance exercise in human skeletal muscle (Figures 2F, 4 and 7)

Viability is controlled when comparing experimental conditions.

Not verified in the article. A viability control for the proposed independent clearance and replacement interventions is absent from the supplied studies.

Overall contractile activation is controlled when comparing experimental conditions.

Different experimental conditions. Controlled calcium activation and force-calcium curves address myofilament function in permeabilized cardiomyocytes, a different preparation from controlling overall activation in intact muscle microtissues.

Cardiomyocyte contractile impairment in heart failure results from reduced BAG3-mediated sarcomeric protein turnover (Methods: Skinned myocyte Force-Ca 2+ experiments; Figure 7a-c)

If the manipulation itself changes force before injury, the experiment cannot separate recovery from that direct effect on force.

Not verified in the article. The supplied studies do not establish pre-injury force neutrality of the proposed clearance and anchoring manipulations.

The proposed test concerns an intracellular protein at the site of force application; the cited comparison concerns persistent muscle stiffness as a sign of delayed extracellular matrix recovery, with average tissue stiffness representing a distinct property.

Not verified in the article. Intracellular force-bearing proteins are relevant to the supplied studies, but the cited extracellular matrix recovery hypothesis and the specified comparison are not supplied as scientific evidence.

The proposed experiment has not yet produced results, so its predicted effects remain untested in this experiment.

Not verified in the article. The submitted proposal explicitly states that its experiment has no results; the supplied literature provides no results for that complete experiment.

The experiment uses preparations from young and old mice to study age-related restoration of periodontal ligament attachment.

Different experimental conditions. The trial studied human periodontal intrabony defects rather than preparations from young and old mice, and it did not test age-related restoration of ligament attachment.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Methods: Patients, enrollment and randomization; Results: Enrollment and teeth; Table 1)

The two cell sources being compared are the residual periodontal ligament on the root and the bone margin.

Different experimental conditions. The comparison was autologous periodontal ligament stem cell sheets plus Bio-Oss versus Bio-Oss alone, both with guided tissue regeneration. Root-side and bone-margin cell populations were not compared.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Methods: Study products and interventions; Figure 2)

The hypothesis proposes that cell origin on the root side affects restoration of mechanical attachment to cementum during aging, beyond the contribution of the total number of progenitor cells.

Not verified in the article. The supplied studies provide no verified test separating the effect of root-side origin from progenitor number on mechanical attachment to cementum during aging.

At the same total cell dose, preserving the population near the root is predicted to provide an advantage specifically in the mechanical connection to cementum.

Not verified in the article. No supplied experiment tests whether preserving the root-side population improves mechanical connection to cementum at an equal total cell dose.

The stated background is that Wnt-responsive periodontal ligament cells contributed to socket healing in a mouse tooth-extraction model.

Not verified in the article. The contribution of Wnt-responsive periodontal ligament cells to mouse extraction-socket healing is stated in the hypothesis, but the supplied scientific texts do not verify that primary experiment.

New bone formation in an extraction socket and restoration of a functioning ligament around a tooth are distinct outcomes, and the tooth-extraction model alone does not resolve the question of which cell source restores attachment.

Not verified in the article. The supplied texts do not explicitly establish the specified distinction between extraction-socket bone healing and functional ligament restoration as a limit on choosing between the two cell sources.

Cells from the root and bone sides are to be labeled in preparations from both young and old mice.

Not verified in the article. No supplied experiment labels both root-side and bone-side cells in preparations from both young and old mice.

The decisive experiment includes separate conditions in which the remnant near the root is preserved or removed, followed by returning equal numbers of cells from either the root-side or the bone-side source.

Different experimental conditions. The clinical intervention placed cell sheet/scaffold transplants into bony defects. It did not preserve or remove a root-side remnant and then return equal numbers of cells from either anatomical source.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Methods: Study products and interventions; Figure 2)

Engraftment and the actual number of living cells must be accounted for when comparing the cell sources.

Not verified in the article. Cell culture characterization and safety assessments do not establish matching of engraftment and actual living cell numbers between root-side and bone-margin populations.

The primary outcome is the force required to detach the restored ligament attachment from the root, measured at the same repair area.

Different experimental conditions. The primary efficacy outcome was increased alveolar bone height; secondary outcomes were clinical periodontal measurements. Detachment force at equal repair area was not measured.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Methods: Efficacy assessment; Results: Evaluation of efficacy; Figure 4; Tables 2 and 3)

If both cell sources yield equal detachment force and equal fiber restoration after engraftment has been matched, an advantage of root-side origin is not supported.

Not verified in the article. No supplied study tests equal detachment force and equal fiber restoration between the two cell sources after matching engraftment. The clinical trial's nonsignificant group differences do not meet this criterion.

The intended practical application is to select a cell source for restoring periodontal ligament attachment.

Matches this study. The article explicitly identifies functional periodontal attachment regeneration and selection of appropriate donor tissues as therapeutic goals. This matches the intended application, but the trial does not select between root-side and bone-margin cells.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Background; Discussion: identification of appropriate donor sources)

The independent experimental unit is the animal or the periodontal ligament donor.

Different experimental conditions. Randomization and outcome reporting were organized around teeth, with some patients contributing multiple teeth. The supplied analysis does not establish the animal or ligament donor as the independent experimental unit.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Methods: Statistics; Results: Enrollment and teeth; Tables 1 and 2)

Samples are to be randomly assigned to the experimental conditions.

Matches this study. The trial explicitly used central randomization to assign teeth to treatment conditions. This matches the random-allocation requirement as a methodological component within a different experimental system.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Results: Enrollment and teeth; Discussion: central randomization)

The outcome is to be assessed with blinding.

Matches this study. The investigator performing follow-up examinations remained blinded to treatment allocation until completion. This matches blinded assessment, although the assessed outcomes were clinical rather than mechanical.

Treatment of periodontal intrabony defects using autologous periodontal ligament stem cells: a randomized clinical trial (Methods: Study design; Study products and interventions; Figure 1)

The conclusion remains indeterminate if the intervention fails to reach its target or if the interval permits both explanations.

Not verified in the article. No supplied study applies the proposed decision rule requiring an indeterminate conclusion when target engagement fails or the interval remains compatible with both explanations.

After glucose normalization, restored insulin secretion may originate either from pre-existing beta-cells that lost mature features and redifferentiated or from selection and expansion of a few resistant clones.

Not verified in the article. Tracing dedifferentiated cells supports their return to functional maturity after pair-feeding. The study does not resolve selection and expansion of a few resistant clones against redifferentiation under the proposed conditions.

Genetic and pharmacologic inhibition of ALDH1A3 as a treatment of β-cell failure (Results, Lineage-tracing ALDH1A3-positive β-cells; Figure 1; Supplementary Figure 1D)

Brief glucose normalization is proposed to enable recovery of beta-cells that lost mature features only within a window before irreversible loss of cellular identity.

Different experimental conditions. Glucose lowering permitted recovery after shorter hyperglycemia but failed after seven months. This tests recovery of function and mass in an ablation model, rather than a redifferentiation window in individually identified dedifferentiated cells.

Glycemic control releases regenerative potential of pancreatic beta cells blocked by severe hyperglycemia (Results, Prolonged severe hyperglycemia results in failure of beta cell recovery; Supplementary Figure S2)

The experiment must include young and old mouse models to test whether beta-cell redifferentiation occurs during natural aging.

Different experimental conditions. The later-treatment animals were older because hyperglycemia had persisted longer. The authors explicitly acknowledge that age and exposure duration could not be separated; this does not reproduce a young-versus-naturally-aged redifferentiation experiment.

Glycemic control releases regenerative potential of pancreatic beta cells blocked by severe hyperglycemia (Results, Prolonged severe hyperglycemia results in failure of beta cell recovery; Supplementary Figure S2)

The stated biological precedent is that insulin-mediated normalization of glycemia in a mouse model of diabetes was accompanied by redifferentiation of some beta-cells; its applicability to natural aging requires separate testing.

Not verified in the article. The insulin-redifferentiation study by Wang et al. is cited, but its full text is absent from the supplied articles. Brereton et al. directly tested prevention with insulin and reversal with glibenclamide, which does not independently verify the stated insulin-treatment precedent.

Reversible changes in pancreatic islet structure and function produced by elevated blood glucose (Discussion, comparison with Wang et al.; reference 37; Results, Figures 1-4)

Mature beta-cells must be labeled before reversible metabolic stress is induced.

Matches this study. Insulin-lineage labeling and a maturity reporter were present before S961-induced reversible metabolic stress. This matches pre-stress labeling as a component, although the lineage label was constitutive rather than an adult pulse.

Reversal of β cell de-differentiation by a small molecule inhibitor of the TGFβ pathway (Results, Using Ucn3 as a marker for the mature β cell state; Figure 3A-B)

Tracking must identify the labeled cells that actually lose their maturity program during metabolic stress.

Matches this study. The combined lineage and Urocortin 3 reporter identifies labeled beta-cells losing a maturity marker during S961 treatment, with accompanying reductions in mature beta-cell transcription factors.

Reversal of β cell de-differentiation by a small molecule inhibitor of the TGFβ pathway (Figure 3A-B; Figure 2 and Figure 2 supplement 1)

Early and late relief from metabolic stress must be compared at the same subsequent glycemia.

Matches this study. Glibenclamide started after 24 hours or four weeks of hyperglycemia produced the same reported mean glucose level two days later and stable control during treatment. This matches the timing-and-glycemia component, but the early arm principally tested prevention rather than recovery of documented dedifferentiated cells.

Reversible changes in pancreatic islet structure and function produced by elevated blood glucose (Results, Expression of Kir6.2-V59M in β-cells rapidly induces diabetes; Figure 1C-D; Figures 2-4)

The analysis must account for both clone proliferation and clone loss.

Not verified in the article. Clonal growth was measured during ordinary islet maintenance, but clone loss was not jointly quantified. The discussion explicitly notes that its proliferation-based estimates assume no beta-cell death.

All β Cells Contribute Equally to Islet Growth and Maintenance (Results, Clonal Analysis Demonstrates that β Cells Contribute Equally to Pancreas Expansion; Discussion)

The primary outcome is the fraction of originally tracked cells that temporarily lose mature features and subsequently recover their response to glucose, with dead cells accounted for.

Different experimental conditions. The study measured conversion of labeled dedifferentiated populations, maturity markers, and insulin secretion. It did not measure the proposed death-accounted fraction of originally mature tracked cells completing loss and recovery of glucose responsiveness.

Genetic and pharmacologic inhibition of ALDH1A3 as a treatment of β-cell failure (Figure 1D-I; Supplementary Figure 1D; Methods, Glucose-stimulated insulin secretion)

If secretion is restored exclusively through expansion of cells that retained mature features, a redifferentiation window has not been demonstrated.

Not verified in the article. Lineage tracing attributes most regeneration to proliferation of pre-existing beta-cells. It does not establish continuous retention of maturity in those cells or apply the specified exclusion criterion to a redifferentiation-window test.

Glycemic control releases regenerative potential of pancreatic beta cells blocked by severe hyperglycemia (Results, Reduction of glycemic load facilitates beta cell regeneration through replication of pre-existing beta cells; Figure 3; Limitations)

The practical interpretation must distinguish preservation of existing beta-cells from stimulation of their replacement.

Matches this study. The study explicitly distinguishes restoration of dedifferentiated cells from their death and replacement, and discusses functional restoration separately from increasing cell number.

Genetic and pharmacologic inhibition of ALDH1A3 as a treatment of β-cell failure (Introduction; Results, Lineage-tracing ALDH1A3-positive β-cells; Discussion)

Extrapolation of the findings to humans requires independent confirmation.

Matches this study. The authors identify species-dependent mechanisms and limited human proliferative capacity, and explicitly require further study to establish clinical relevance.

Glycemic control releases regenerative potential of pancreatic beta cells blocked by severe hyperglycemia (Discussion, Potential relevance to human diabetes; Limitations of the study)

The independent experimental unit is the islet donor.

Not verified in the article. The supplied studies report animals, biological samples, islets, or technical replicates, but do not verify donor-level independence for the proposed longitudinal recovery outcome.

Samples must be randomly assigned to experimental conditions.

Matches this study. Random assignment to control, rosiglitazone, or KOTX1 diets is explicitly reported for the diet-induced obesity experiment. This procedural component does not establish randomization of the proposed age-and-timing experiment.

Genetic and pharmacologic inhibition of ALDH1A3 as a treatment of β-cell failure (Results, Pharmacological inhibition of ALDH1A3 improves diabetes; Figure 4)

The outcome must be assessed blindly.

Not verified in the article. Blinded assessment of the specified recovery outcome is not documented in the supplied texts.

The conclusion remains indeterminate if the intervention does not reach its target or if the interval allows both redifferentiation and expansion of resistant clones as explanations.

Not verified in the article. No supplied study specifies the combined decision rule that failed target engagement or an interval compatible with both mechanisms leaves this test indeterminate.

The biological system comprises limbal cell cultures from independent young and older donors, with regenerative reserve assessed in relation to long-term corneal renewal.

Different experimental conditions. Human limbal cultures from different donor age groups were studied, but regenerative potential was assessed through outgrowth, markers and single-round colony formation rather than demonstrated long-term corneal renewal.

Limbal epithelial stem cell sheets from young donors have better regenerative potential (Materials and methods: Tissue procurement, Clonal proliferation; Results, Figures 1-5.)

With aging, limbal cells may lose resistance to storage before their immediate viability declines.

Not verified in the article. Age-associated differences in stem/progenitor properties during storage at 4 °C were measured. The temporal claim that storage resistance declines before immediate viability was not tested.

Limbal epithelial stem cell sheets from young donors have better regenerative potential (Results: Effects of donor’s age on the activation of limbal stem/progenitor cells during the storage period; Figure 5.)

Storage and thawing may deplete serially self-renewing clones while preserving immediate cell viability, so equal numbers of viable cells may conceal a loss of regenerative reserve and capacity for long-term corneal renewal.

Different experimental conditions. Membrane integrity, metabolism and colony formation were measured after cryoprotectant exposure at 4 °C, whereas actual freezing and thawing were assessed through dye-efflux phenotype and membrane integrity. Serial clone depletion with preserved viability and impaired long-term renewal was not demonstrated.

Defining the optimal cryoprotectant and concentration for cryopreservation of limbal stem cells (Main article: cryoprotectant-tolerance methods; Figures 2-3.)

After thawing, cultures from older donors are predicted to lose more serially self-renewing clones and tolerate a second injury less well than cultures from young donors.

Not verified in the article. No supplied study compared young- and older-donor cultures for both post-thaw loss of serially self-renewing clones and reduced tolerance of a second injury.

Selection by serial colony formation is proposed to improve the result, without specifying the selection procedure or the particular result improved.

Not verified in the article. Colony formation was used to characterize cultures, but an intervention selecting cultures or cells by serial colony formation and demonstrating an improved result was not reported.

Paired cultures must be split into fresh and thawed conditions.

Different experimental conditions. Fresh and organ-culture-stored tissues came from separate donor groups and eye banks. This substitutes an unpaired tissue-storage comparison for paired cultures split into fresh and thawed conditions.

Yield and Viability of Human Limbal Stem Cells From Fresh and Stored Tissue (Methods: Limbal Tissue; Results: donor characteristics.)

Predictions from a conventional viability test and serial clonogenic analysis must be compared on independent explants at equal live-cell numbers.

Different experimental conditions. Trypan-blue viability testing and colony assays with specified viable-cell seeding numbers were performed. These were first-passage colony measurements, without serial clonogenic prediction or comparison of predictive accuracy on independent explants.

Yield and Viability of Human Limbal Stem Cells From Fresh and Stored Tissue (Methods: Digestion of Limbal Tissue and Viability Assay; CFE Assays.)

Independent young and older donors must be compared under conditions of equal initial injury.

Not verified in the article. The supplied age-group comparisons did not apply a matched initial injury to independent young and older donors.

The interaction between age and the factor under study must be tested in advance, and a confidence interval for the effect must be estimated; the factor is not further specified.

Not verified in the article. No supplied study reports the required advance age-by-factor interaction test together with an effect confidence interval. Age associations and group comparisons do not establish this condition.

The primary outcome is prediction error for repeated epithelial closure in independent donors after two injury cycles.

Different experimental conditions. Two injury cycles and slower second-wound closure were studied in mice. The outcome was observed wound area, not prediction error in independent donors, and the experiment lacked donor-age and thawed-culture comparisons.

Differentiation Trajectory of Limbal Stem and Progenitor Cells under Normal Homeostasis and upon Corneal Wounding (Methods 2.2; Results 3.2; Figure 4.)

Serial clonogenic analysis is predicted to add predictive accuracy beyond viability and initial-defect risk; failure to add accuracy would refute this prediction.

Not verified in the article. No supplied study tested whether serial clonogenic analysis improves prediction beyond viability and initial-defect risk, with failure to improve accuracy serving as the specified falsification criterion.

The stated scientific basis includes observations after transplantation of autologous cultures, including an association between culture composition and outcome.

Matches this study. The discussion explicitly recounts an association between p63-positive culture composition and transplantation outcome, citing the clinical literature on autologous cultures. This matches the stated background basis only; the supplied article itself studied cultured donor cells rather than those clinical outcomes.

Limbal Stem Cells from Aged Donors Are a Suitable Source for Clinical Application (Discussion; references 26 and 50.)

The stated scientific basis also includes a consensus on treatment stages and the ocular surface condition required for restoration, without specifying particular stages or conditions.

Not verified in the article. The cited global management consensus is not supplied as a source text. General treatment discussions in the supplied articles do not verify the stated consensus on treatment stages and ocular surface conditions.

The timing of withdrawal of Hedgehog blockade should be determined by the remaining reserve of competent progenitors rather than by the number of lost taste buds.

Not verified in the article. Neither supplied study tests a withdrawal rule based on measured competent-progenitor reserve or compares its predictive value with taste-bud loss.

In aged taste epithelium, the same loss of mature taste buds may accompany different reserves of competent progenitors.

Different experimental conditions. The study compares natural aging and age-dependent organoid differentiation. It does not compare aged epithelium with equivalent mature-bud loss after blockade but different measured progenitor reserves.

Molecular Mechanisms of Age-Related Taste Dysfunction Deciphered by Spatiotemporal Transcriptomics (Results 2.2-2.3; Figures 2K-P and 3G-J; Methods 4.21)

A preserved reserve of competent progenitors is predicted to permit functional taste recovery even after late withdrawal of pathway suppression, whereas an exhausted reserve is predicted to prevent recovery.

Not verified in the article. Structural recovery and persistent failure of some papillae to recover were observed. Progenitor survival or loss was inferred, without a direct reserve measurement establishing functional recovery after late withdrawal.

Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling (Results, Loss of taste papillae and taste buds after HH/GLI blockade is reversible; Figure 9; Discussion, Recovery from HH signaling suppression)

The stated experimental background is that loss of taste organs during Hedgehog/Smoothened suppression and heterogeneous recovery of taste function after withdrawal have been studied in mice.

Not verified in the article. The primary experiments demonstrate taste-organ loss and heterogeneous structural recovery in mice. Functional recovery after pharmacological blockade is discussed through a cited conference abstract, rather than directly measured in this article.

Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling (Results, Figure 9; Discussion, Pharmacologic blockade of HH signaling and epithelial HH suppression; references 31 and 60)

The decisive experiment labels progenitors in young and old mice before reversible Smoothened blockade.

Different experimental conditions. Recovery was tested using reversible epithelial GLI repression. The study does not perform progenitor labeling before reversible Smoothened blockade in paired young and old cohorts; its EdU labeling occurred shortly before sacrifice.

Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling (Methods, Mouse strains and transgene induction; Immunostaining and imaging; Figure 9)

The experiment compares groups with the same loss of mature taste buds but different progenitor reserves measured beforehand.

Not verified in the article. Neither study compares groups matched for mature taste-bud loss while differing in progenitor reserve measured beforehand.

After withdrawal of blockade, the experiment must confirm resumption of pathway activity and preservation of innervation.

Not verified in the article. Epithelial pathway activity returns after withdrawal, and innervation persists during GLI suppression. The supplied experiments do not verify both conditions after withdrawal within the proposed young-versus-old Smoothened-blockade comparison.

Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling (Figure 5; supplementary Figures S4, S6, S9 and S10; Methods, Innervation)

The primary outcome is the taste nerve response to a standard substance, measured one previously measured renewal cycle after withdrawal of blockade.

Different experimental conditions. Recovery outcomes are papilla morphology, taste-bud profiles and pores at scheduled withdrawal intervals. These substitute structural measurements for a taste nerve response timed to a previously measured renewal cycle.

Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling (Figure 9; supplementary Figure S8; Methods, Quantification)

The progenitor reserve predictor is rejected if baseline reserve fails to improve prediction beyond the number of taste buds and nerve fibers in an independent sample.

Not verified in the article. Neither study validates the added predictive value of baseline reserve beyond bud and nerve-fiber counts in an independent sample. The aging study's held-out classification predicts age from transcriptomes, which is a different task.

The proposed practical application is to guide the choice between pathway reactivation and cell replenishment.

Not verified in the article. Neither supplied study tests reserve-guided selection between pathway reactivation and cell replenishment.

The prediction is restricted to damage caused by Hedgehog/Smoothened suppression.

Matches this study. The recovery experiment concerns injury induced by Hedgehog-pathway suppression through epithelial GLI repression, matching the specified damage category. It does not establish the proposed reserve predictor.

Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling (Results, Figure 9; Methods, Mouse strains and transgene induction)

The independent experimental unit is an animal or an organoid donor.

Matches this study. Animals provide the biological replicates for the principal recovery measurements, with papilla measurements summarized by tongue. Some separate cellular analyses use papilla counts and do not establish donor-level replication for the proposed reserve experiment.

Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling (Methods, Mouse strains and transgene induction; Quantification; Statistics; Figure 9)

Samples must be randomly assigned to experimental conditions.

Not verified in the article. Random assignment to experimental conditions is not documented. Random division of transcriptomic data into training and test sets does not satisfy this requirement.

The outcome must be assessed with blinding.

Not verified in the article. The supplied methods do not document blinded outcome assessment for the proposed recovery test.

The conclusion remains indeterminate if the intervention fails to engage its target or if the interval permits both explanations.

Not verified in the article. Although pathway suppression is checked experimentally, neither study specifies the proposed indeterminate-conclusion rule for failed target engagement or an interval compatible with both explanations.

The proposed experiment concerns alveolar regeneration after injury in young and old animals, with the central hypothesis addressing restoration of the aged alveolar barrier.

Different experimental conditions. The study examines alveolar regeneration after bleomycin injury, primarily in mice aged 6-10 weeks. It does not include the required young-versus-old comparison or establish restoration of the aged alveolar barrier.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (STAR Methods, Mouse Models and Bleomycin Administration)

The stated biological basis is a mouse model in which interleukin-1β (IL-1β) promoted the emergence of transitional descendants of alveolar type 2 epithelial cells (AT2), while prolonged exposure inhibited their maturation into alveolar type 1 epithelial cells (AT1).

Matches this study. Mouse lineage tracing, receptor deletion and organoid experiments establish that IL-1β promotes AT2-derived transitional progenitors, whereas sustained IL-1β prevents terminal AT1 maturation.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figures 2, 4 and 7A-H)

IL-1β signaling must be removed after transitional cells have appeared, using late receptor blockade.

Different experimental conditions. IL-1β was withdrawn from organoids after 14 days of exposure, followed by seven additional culture days. The receptor experiment used AT2-specific Il1r1 deletion before injury, rather than late receptor blockade after transitional-cell formation.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figure 7D-E; Figure 4A-E)

The central hypothesis is that removing IL-1β signaling allows the previously formed transitional descendants of AT2 to mature into AT1 and provide most of the restoration of the aged alveolar barrier.

Different experimental conditions. Separate experiments demonstrate transitional-cell descendants with AT1 identity and recovery of mature AT1 marker expression after organoid IL-1β withdrawal. They do not establish that the pre-existing cohort provides most functional barrier recovery in aged animals.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figure 3E-L and Figure 7D-E)

The alternative explanation is that the existing transitional cells remain unproductive and the tissue is replaced by a new wave of descendants from AT2 cells that have not yet been activated.

Not verified in the article. Pseudotime analysis suggests a senescent transitional subset with an alternative fate and a possible route bypassing the transitional state. Replacement by a newly activated AT2 wave after late IL-1β removal in aged tissue was not tested.

Regulation of epithelial transitional states in murine and human pulmonary fibrosis (Results, Figure 7B; Discussion, Figure 8)

Transitional cells must be labeled before IL-1β signal removal, and subsequent AT2 descendants must be labeled separately, in both young and old animals.

Different experimental conditions. Ndrg1 and Krt8 reporters trace transitional cells, and separate experiments trace AT2 descendants. The study does not temporally distinguish the earlier transitional cohort from subsequent AT2 descendants around signal withdrawal in both age groups.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figure 3 and Figure S4; STAR Methods, Primary 3D Lung organoid co-culture)

Late receptor blockade must be compared with a control at the same stage of injury.

Different experimental conditions. The study includes organoid exposure comparisons and genetically controlled receptor-deletion experiments. Neither is a late receptor-blockade versus control comparison at a matched injury stage in young and old animals.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figure 7D-E; Figure 4A-E)

After the blockade-versus-control comparison, differentiation of the previously labeled transitional-cell cohort must be selectively restricted in independent experimental groups to test its necessity for barrier restoration.

Different experimental conditions. AT2-specific Il1r1 or Hif1α deletion impairs generation of transitional progenitors and subsequent AT1 differentiation. This differs from selectively restricting differentiation of an already labeled transitional cohort after the blockade comparison.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figure 4 and Figure S6D-H)

The purity of the cell labels must be checked.

Matches this study. Reporter specificity was checked using airway, AT2, AT1 and transitional-cell markers, uninjured controls and flow cytometry. The authors also disclose possible residual-tamoxifen confounding for Il1r1 tracing; these checks do not validate the proposed dual-cohort labeling scheme.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figure 3F-I and Figure S4B-K; Limitations of Study)

The initial size of the alveolar defect must be checked.

Different experimental conditions. Early inflammation and permeability were compared four days after bleomycin in Krt8-deficient and control mice. These injury measurements do not establish equal initial alveolar defect size before the proposed late blockade and cohort manipulation.

Regulation of epithelial transitional states in murine and human pulmonary fibrosis (Results, Figure 2E-F)

The primary outcome is recovery of alveolar barrier function, assessed by alveolar tracer leakage after one week.

Different experimental conditions. Fluorescent albumin leakage into alveolar airspaces was measured after acute AT1 ablation or infectious injury. This is a relevant functional assay, but not the specified one-week outcome after late IL-1β receptor blockade in aged animals.

Evidence for lung barrier regeneration by differentiation prior to binucleated and stem cell division (Results, Figure 3B-E; Materials and methods, Bronchoalveolar lavage and pulse oximetry)

AT1 morphology must be assessed as a mechanistic measure of regeneration.

Matches this study. Lineage-labeled descendants of transitional cells were examined for AT1 morphology and marker expression during regeneration. This matches the morphological component, although the aged late-blockade experiment is absent.

Inflammatory Signals Induce AT2 Cell-Derived Damage-Associated Transient Progenitors that Mediate Alveolar Regeneration (Results, Figure 3J-K)

The animal is the experimental unit.

Matches this study. The study explicitly defines biological replicates as different animals and reports animal-level barrier measurements. This matches the experimental-unit requirement as a component.

Evidence for lung barrier regeneration by differentiation prior to binucleated and stem cell division (Materials and methods, Statistical analysis; Figure 3C-E)

Barrier recovery when the earlier labeled cohort is disabled would reject the necessity of that cohort for restoration.

Not verified in the article. No supplied study tests whether barrier recovery persists when differentiation of the earlier labeled transitional cohort is disabled under the proposed late-blockade conditions.

A large fraction of labeled cells is insufficient to support the proposed functional contribution unless accompanied by improvement in barrier function.

Not verified in the article. The supplied studies do not apply the proposed joint criterion linking the earlier cohort's labeled-cell fraction to improvement in tracer-defined barrier function after late blockade in aged tissue.

Secondary inflammation caused by the experimental manipulation makes interpretation of the experiment ambiguous.

Not verified in the article. Although inflammation is measured in related experiments, none assesses secondary inflammation caused by selectively restricting the earlier transitional cohort as a confounder of the proposed necessity test.

The comparison with a related hypothesis describes release of both inflammatory and mechanical constraints on incomplete alveolar regeneration; the author states that the intervention is the same, while the divergent predictions concern the cellular origin of the functional benefit.

Different experimental conditions. Macrophage recruitment, fibroblast persistence and stiff substrates are linked experimentally to transitional-cell accumulation. The study does not reproduce the same intervention releasing inflammatory and mechanical constraints while distinguishing cellular sources of functional recovery.

Regulation of epithelial transitional states in murine and human pulmonary fibrosis (Results, Figure 5A-E; Discussion, Figure 8)

The cellular source of functional improvement after late removal of inflammation in aged tissue remains unresolved, and results of the proposed experiment have not yet been obtained.

Not verified in the article. The supplied literature provides no result for the complete proposed aged-tissue experiment. It leaves the stated cellular-source question unresolved within these materials, while the author's statement that the proposed results have not been obtained is contextual information.

The experiment uses donor corneas as recipient tissues and compares independent young and elderly donors to test whether aged tissue retains regenerative reserve.

Not verified in the article. Human donor corneas served as recipient substrates, but the study did not compare independent young and elderly recipient groups for regenerative reserve.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Methods: Corneal tissue sourcing; Organ culture of human corneas.)

The interventions are performed after limbal-cell depletion.

Matches this study. The ex vivo protocol removed epithelial cells, verified their complete removal, and reseeded limbal epithelial stem cells; its alkali-burn arm also treated damaged limbal tissue.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Methods: Organ culture of human corneas; Figure 6.)

The condition of the recipient corneal surface and basement membrane limits cell attachment and stable epithelial coverage, and age-related changes in this niche may reduce the benefit of an additional cell dose.

Not verified in the article. Substrate mechanics affected epithelial phenotype and recovery, but the proposed causal link from recipient aging to impaired attachment and reduced benefit of additional cells was not tested.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Results: Collagenase treatment restores limbus capacity to support LESCs after alkali burn; Figures 6-7.)

Surface restoration includes leveling the basement membrane to prepare the recipient substrate.

Different experimental conditions. The intervention softened tissue with collagenase and partially degraded basement-membrane components. It did not level the basement membrane, and the authors reported no evident limbal topographic alterations.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Figures 4 and 6; Discussion; Methods: Collagenase treatments.)

Surface restoration and cell dose are varied independently across four groups combining a damaged or restored surface with the initial or doubled cell dose.

Different experimental conditions. The study compared control, alkali-burned, and collagenase-treated burned tissue, using 5 × 10^5 cells per cornea. It did not cross two surface conditions with initial and doubled cell doses.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Figure 6; Methods: Organ culture of human corneas.)

The age and source of the transplanted donor cells are held constant across comparisons.

Not verified in the article. Cells from individual donors were cultured separately, and independent experiments used different donors. Holding transplanted-cell age and source constant across recipient-age and dose comparisons was not documented.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Methods: Isolation and culture of corneal limbal epithelial cells; Organ culture of human corneas.)

The degree of initial injury is matched across the four experimental groups and between young and elderly recipient corneas.

Not verified in the article. A defined alkali exposure standardized the injury procedure, but equivalent initial injury across the proposed four groups and young versus elderly recipient corneas was not demonstrated.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Methods: Organ culture of human corneas.)

Restoring the recipient niche is predicted to restore the cell-dose response predominantly in elderly recipient tissues.

Not verified in the article. None of the supplied studies tested whether niche restoration preferentially restores the transplanted-cell dose response in elderly recipient tissues.

Basement-membrane leveling is predicted to produce a greater improvement in stable epithelial coverage than doubling the cell number on a damaged substrate.

Not verified in the article. No supplied study directly compared basement-membrane leveling with doubling the cell number on damaged substrate for stable epithelial coverage.

The analysis must prospectively specify a test of the interaction between age and the investigated factor and estimate a confidence interval for the effect.

Not verified in the article. The statistical methods mention analysis of variance and a 95% confidence interval, but no prospectively specified recipient-age-by-intervention test or confidence interval for that effect.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Methods: Statistical analysis.)

The primary outcome is the fraction of the surface covered by stable corneal epithelium after a standardized adhesion challenge on day 14.

Different experimental conditions. Day-14 fluorescein uptake measured barrier disruption in wounded mice. This differs from the fraction of donor-corneal surface retaining epithelium after a standardized adhesion challenge.

Age-Related Differences in the Mouse Corneal Epithelial Transcriptome and Their Impact on Corneal Wound Healing (Methods: Evaluation of Corneal Barrier Function and Residual Haze 14 Days After Debridement; Figure 4C.)

The prediction is refuted if doubling the cell dose consistently outperforms substrate preparation or if preparation produces no change in cell attachment and epithelial coverage.

Not verified in the article. The supplied studies did not implement the specified falsification comparison between dose doubling and substrate preparation, including attachment and coverage outcomes.

The stated scientific rationale includes a consensus on treatment stages and the ocular-surface condition required for restoration, together with research on how corneal-substrate mechanics influence limbal epithelial stem-cell maintenance and differentiation.

Not verified in the article. Gouveia and colleagues directly support the substrate-mechanics rationale. The cited Deng consensus text is absent from the supplied literature, so the complete two-part rationale cannot be verified here.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation (Introduction; Results; Figures 3-7.)

The experiment compares young and old mice and examines meningeal lymphatic drainage to the deep cervical lymph nodes.

Matches this study. Young and old mice were compared for meningeal lymphatic structure and cerebrospinal fluid tracer drainage to deep cervical lymph nodes.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Meningeal lymphatics in aging; Extended Data Figures 6a-f and 7a-g.)

After restoration of meningeal lymphatic drainage in old mice, improved clearance of large soluble cargo is hypothesized to depend more strongly on patency of the route to the deep cervical lymph nodes than clearance of small soluble cargo.

Not verified in the article. VEGF-C-associated drainage enhancement depended on an unligated route in old mice, but stronger dependence for large than small soluble cargo was not tested.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Figure 2m-t; Extended Data Figure 4.)

The competing explanation is that the transport changes are entirely attributable to changes in brain perfusion.

Not verified in the article. The study measured cerebrospinal fluid tracer influx and vascular hemodynamics, but did not test whether perfusion entirely explained a paired size-dependent transport response. Blood flow and oxygenation were unchanged after VEGF-C treatment.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Meningeal lymphatics in aging; Extended Data Figure 6n-r.)

The motivating observations are that intervention on the meningeal lymphatic network in old mice improved macromolecule outflow while perfusion and behavior also changed; these observations leave route selectivity and a general change in fluid transport unresolved.

Matches this study. The motivating drainage, brain tracer influx and behavioral effects were reported in aged mice, without resolving cargo-size selectivity. The reported perfusion improvement concerned cerebrospinal fluid influx, rather than increased blood perfusion.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Figure 2e-t; Extended Data Figures 6n-r and 7a-u.)

Young and old mice receive local enhancement of vascular endothelial growth factor C (VEGF-C) signaling or a control intervention.

Matches this study. Young and old mice received locally applied VEGF-C-containing hydrogel or vehicle, with drainage assessed in both age groups.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Extended Data Figure 7a-g; Methods, Transcranial recombinant VEGF-C delivery.)

Reversible restriction of the transport route to the lymph nodes or a sham procedure is an independent experimental factor, combined with VEGF-C signaling enhancement or its control in each age group.

Different experimental conditions. Old mice received crossed VEGF-C/control and ligation/sham interventions, but ligation used non-absorbable sutures without demonstrated reversal. The same factorial experiment was not performed in both age groups.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Figure 2m-t; Methods, Lymphatic vessel ligation.)

Two inert tracers with different hydrodynamic sizes and matched chemistry are introduced simultaneously into the same animal.

Different experimental conditions. Ovalbumin, amyloid-beta and low-density lipoprotein were injected separately in ablation experiments. These chemically different cargos do not constitute simultaneous, inert, chemistry-matched size probes in the same animal.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Extended Data Figure 4; Methods, Brain parenchymal injections.)

Cerebrospinal fluid pressure, brain perfusion, and leakage are measured.

Not verified in the article. Pressure, blood-brain barrier integrity and perfusion-related measurements appear in separate experiments. Their joint assessment under the proposed age-by-treatment-by-reversible-restriction conditions is unverified.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Extended Data Figures 1i-j, 2a-b and 6n-r; Methods, Intracranial pressure measurement.)

The primary test evaluates the interaction between the intervention and route patency using the ratio of restored delivery of the large and small tracers to the lymph nodes.

Different experimental conditions. The crossed treatment-and-ligation experiment quantified ovalbumin signal in lymph nodes. It did not use the restored-delivery ratio of large and small tracers as the interaction endpoint.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Figure 2s-t.)

Tracer delivery is assessed over a fixed observation window defined by a pilot experiment.

Not verified in the article. Tracer drainage was assessed at a specified two-hour endpoint, but selection of the proposed observation window by a pilot experiment was not documented.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Extended Data Figure 7a; Methods, Statistical analysis and reproducibility.)

The animal is the experimental unit.

Matches this study. Drainage and behavioral comparisons used mice as independent units, with measurements from multiple tissue sections averaged within samples. This match concerns those experiments, not pooled endothelial-cell sequencing.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Figure 2m-t; Methods, Immunohistochemistry, imaging and quantifications.)

The clearance route must be confirmed so that the within-animal comparison of the two cargo sizes addresses route function rather than merely lymphatic vessel number or size.

Different experimental conditions. Ligation and node tracer measurements tested functional route dependence beyond vessel morphology. However, route confirmation was not combined with the proposed within-animal comparison of two cargo sizes.

Functional aspects of meningeal lymphatics in aging and Alzheimer's disease (Figure 2m-t; Extended Data Figure 3a-d.)

Equal changes in both tracers that are determined by perfusion would reject the hypothesis of size selectivity.

Not verified in the article. No supplied study applied the specified rejection criterion of equal paired-tracer changes explained by perfusion after lymphatic restoration.

If restriction of the route itself changes cerebrospinal fluid pressure, the experiment cannot distinguish the proposed explanations.

Different experimental conditions. A related study checked pressure after lymphatic ligation and found no significant elevation during its observation window. It used young mice and hypotensive drugs, rather than the proposed ageing, VEGF-C and reversible-restriction design.

Blood pressure lowering enhances cerebrospinal fluid efflux to the systemic circulation primarily via the lymphatic vasculature (Figure 6; Additional file 5, Figure S5; Methods, Animals and housing.)

The inference concerns drainage and does not establish restoration of memory.

Not verified in the article. This is a boundary on the proposed inference. Published behavioral findings do not establish memory restoration from the proposed two-tracer drainage experiment.

The proposed comparison with aged skin is that growth of lymphatic capillaries alone would not restore aged skin without functioning collecting lymphatic vessels, emphasizing the dependence of restoration on a functional downstream route.

Not verified in the article. The supplied articles discuss peripheral lymphatic ageing and collecting-vessel function, but provide no direct test that aged-skin restoration by capillary growth requires functioning collectors.

The proposed experiment has not yet produced results.

Not verified in the article. The hypothesis record identifies the experiment as unperformed; the supplied literature contains no results from that complete experiment and cannot independently verify its current execution status.

The proposed rehabilitation study concerns aged tendons in people whose capacity to generate force slowly has already recovered.

Different experimental conditions. Habets and colleagues enrolled recreational athletes aged 18-65 with symptomatic chronic Achilles tendinopathy, rather than an aged-tendon cohort selected after recovery of slow-force capacity.

No Difference in Clinical Effects When Comparing Alfredson Eccentric and Silbernagel Combined Concentric-Eccentric Loading in Achilles Tendinopathy: A Randomized Controlled Trial (Methods: Participants; Results: Table 1)

Recovered maximal tendon strength may conceal a persistent inability to tolerate a rapid rise in force.

Not verified in the article. The supplied studies do not demonstrate persistent rapid-loading intolerance after maximal strength has recovered in older tendons.

The study examines the capacity of aged tissue to adapt to repeated loading, with progressive training of force-development speed expected to preferentially improve function during rapid movement.

Different experimental conditions. Tsai and colleagues demonstrated Achilles tendon adaptation to repeated loading in healthy young men. They varied session frequency and loading volume while keeping loading rate constant, so preferential improvement of rapid function through speed training in aged tissue was not tested.

Effect of the temporal coordination and volume of cyclic mechanical loading on human Achilles tendon adaptation in men (Materials and methods: Participants and experimental design; Intervention protocols; Results: Figure 3)

A late rehabilitation phase of rapid, controlled force development is added to improve the aged tendon's ability to tolerate sudden loading.

Different experimental conditions. The Silbernagel program increased exercise speed and introduced plyometrics in its final phase. This was part of a complete program for symptomatic Achilles tendinopathy, not an isolated addition after slow-force recovery in older people.

No Difference in Clinical Effects When Comparing Alfredson Eccentric and Silbernagel Combined Concentric-Eccentric Loading in Achilles Tendinopathy: A Randomized Controlled Trial (Methods: Interventions)

All participants complete a common initial program before assignment to the comparison groups.

Different experimental conditions. Participants were randomized after baseline assessment and then began their assigned programs. They did not complete a common initial rehabilitation program before allocation.

No Difference in Clinical Effects When Comparing Alfredson Eccentric and Silbernagel Combined Concentric-Eccentric Loading in Achilles Tendinopathy: A Randomized Controlled Trial (Methods: Recruitment and Randomization; Interventions)

Participants are assigned to either slow loading or progressive speed training, and the outcomes of these groups are compared.

Different experimental conditions. The comparison was isolated eccentric loading versus combined concentric-eccentric loading progressing to plyometrics. The programs also differed in exercise content and frequency, preventing isolation of slow loading versus progressive speed training.

No Difference in Clinical Effects When Comparing Alfredson Eccentric and Silbernagel Combined Concentric-Eccentric Loading in Achilles Tendinopathy: A Randomized Controlled Trial (Methods: Interventions)

Peak force and total work are matched between the slow-loading and progressive-speed-training groups.

Not verified in the article. No supplied study verifies matching both peak force and total work between the proposed slow-loading and progressive-speed-training groups.

Progressive speed training is predicted to improve the force safely reached during the first 200 ms of a standard task compared with slow loading.

Not verified in the article. No supplied study reports the predicted between-group improvement in force safely reached during the first 200 ms of a standardized task under the proposed rehabilitation conditions.

Progressive speed training is predicted to improve tolerance of stair descent compared with slow loading.

Not verified in the article. The supplied reports do not establish improved stair-descent tolerance from progressive speed training versus slow loading. General symptom and function scores do not verify this specific outcome.

Gains confined to the training exercise that do not transfer to the standardized task would refute the prediction.

Not verified in the article. No supplied study applies the proposed falsification criterion of training-exercise gains failing to transfer to the standardized rapid-force task.

Worsening symptoms would refute the prediction.

Not verified in the article. The clinical trials monitored pain and adverse events, but none tested symptom worsening as a refutation of this specific late-phase speed-training prediction in older people with recovered slow-force capacity.

The stated scientific basis includes a clinical trial of progressive tendon-loading exercise therapy for patellar tendinopathy, whose primary outcome reflected symptoms and function.

Matches this study. Breda and colleagues conducted the stated randomized trial of progressive tendon-loading exercise therapy for patellar tendinopathy. Its primary outcome measured pain, function and ability to participate in sports.

Effectiveness of progressive tendon-loading exercise therapy in patients with patellar tendinopathy: a randomised clinical trial (Methods: Outcomes; Results: Primary outcome; Figure 4; Table 2)

The stated scientific basis also includes research in humans on how cyclic strain characteristics affect Achilles tendon adaptation.

Matches this study. Human Achilles tendon adaptation to cyclic loading characteristics was directly studied by varying loading frequency and volume. The article also identifies the cited Bohm study on strain rate and duration, although that study's own supplied page contains only an access notice.

Effect of the temporal coordination and volume of cyclic mechanical loading on human Achilles tendon adaptation in men (Materials and methods: Intervention protocols; Results: Figures 3-4; References: 26)

Aging of the muscle-tendon unit may selectively reduce tolerance to loading in a lengthened position, producing an age-related torque deficit at extreme angles.

Not verified in the article. The supplied studies do not directly test whether aging selectively reduces load tolerance at longer muscle-tendon lengths and causes an extreme-angle torque deficit.

Aged tissue is hypothesized to adapt to repeated loading in a lengthened position, restoring load tolerance and the working range.

Different experimental conditions. Eriksen and colleagues demonstrated load-dependent tendon adaptation in adults aged 62-70 years, but compared heavy and moderate loading over 12 months. They excluded recent patellar tendinopathy and did not test restoration of a lengthened working range.

Load magnitude affects patellar tendon mechanical properties but not collagen or collagen cross-linking after long-term strength training in older adults. (Methods: Participants and Interventions; Results: Patellar tendon mechanical properties; Figure 4.)

With comparable work, progressive training in the lengthened range should preferentially reduce the age-related torque deficit at extreme angles.

Different experimental conditions. Guex and colleagues observed angle-specific torque gains after three weeks in healthy young adults, but no significant group-by-time interaction at any tested angle. Age-related deficits were not assessed, and the authors acknowledged potentially greater training loads in the long-length group.

Hamstring Architectural and Functional Adaptations Following Long vs. Short Muscle Length Eccentric Training. (Methods: Subjects and Eccentric resistance training; Results: Functional adaptations; Figure 3; Discussion.)

Training at a longer muscle-tendon unit length should be introduced gradually with equal muscular effort, with improvement in function expected at those angles.

Different experimental conditions. Both groups performed maximal eccentric contractions with progressively more sets, but hip position was fixed at 0° or 80° from the outset. Gradual introduction of longer lengths and verified equality of muscular effort were not established.

Hamstring Architectural and Functional Adaptations Following Long vs. Short Muscle Length Eccentric Training. (Methods: Eccentric resistance training; Figure 1; Discussion.)

The proposed experiment concerns older individuals with stable tendinopathy.

Different experimental conditions. The clinical trial enrolled men aged 20-55 years with Achilles tendinopathy lasting more than three months. It did not specifically recruit an older stable-tendinopathy population; chronic duration alone does not verify clinical stability.

Evidence-Based High-Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross-Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial. (Materials and Methods: Design and eligibility criteria; Table 1.)

The experiment should compare training through standard and extended ranges of motion, using equal total work and safe progression.

Different experimental conditions. Colard and colleagues progressively adjusted training loads but compared two separate 30° ankle ranges at short and long muscle lengths. They did not compare a standard range with its extension or establish equal total mechanical work.

Eccentric training at long muscle lengths induces greater corticospinal and spinal reflex plasticity than eccentric training at short muscle lengths. (Methods 2.4.1-2.4.2; Table 1.)

Effort across angles and accompanying loads should be monitored.

Not verified in the article. Training diaries recorded loads, progression and other exercise activities, but strength testing used a fixed neutral ankle position. The combined requirement to monitor effort across angles and accompanying loads was only partly covered.

Evidence-Based High-Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross-Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial. (Materials and Methods: Intervention; Primary Outcomes: Mechanical and Material Properties.)

A younger comparison group should have the same clinical condition and comparable exposure.

Not verified in the article. No supplied study included the required older-versus-younger comparison with the same tendinopathy and comparable intervention exposure.

The age-by-intervention interaction should be specified in advance.

Not verified in the article. The supplied analyses test training-group and time effects, but do not establish a prespecified age-by-intervention interaction.

The analysis should account for baseline injury severity.

Not verified in the article. Baseline clinical severity was recorded and compared between groups, but the reported analysis did not adjust treatment effects for baseline injury severity. Baseline comparability testing does not fulfill that adjustment requirement.

Evidence-Based High-Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross-Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial. (Materials and Methods: Statistical Analysis; Table 1.)

The primary outcome should be tolerable torque in a predefined extreme functional range after 16 weeks.

Different experimental conditions. The clinical trial measured maximal isometric plantar-flexor strength at a neutral ankle position after 12 weeks, alongside tendon and clinical outcomes. It did not measure tolerable torque in a predefined extreme functional range after 16 weeks.

Evidence-Based High-Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross-Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial. (Materials and Methods: Primary Outcomes and Mechanical and Material Properties; Figure 4.)

Equal changes in torque would refute the prediction; the submitted text does not specify which comparison defines equality.

Not verified in the article. The absence of significant group-by-time interactions in young adults neither establishes equivalent torque changes nor implements the proposed refutation criterion. The submitted hypothesis itself leaves the comparison defining equality unspecified.

Hamstring Architectural and Functional Adaptations Following Long vs. Short Muscle Length Eccentric Training. (Results: Functional adaptations; Figure 3.)

Improvement at new angles accompanied by a sustained loss of overall function would also refute the prediction.

Not verified in the article. Countermovement-jump height decreased while clinical scores improved, but the study did not demonstrate gains at new angles accompanied by sustained overall functional loss. This does not implement the proposed refutation test.

Evidence-Based High-Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross-Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial. (Results: Jump Performance and VISA-A Score; Discussion.)

The stated scientific basis includes a clinical trial of loading programs whose primary outcome reflected symptoms and function.

Matches this study. The article identifies Breda and colleagues' randomized loading trial and describes its symptom-and-function outcome using the patellar tendinopathy assessment score. Its own trial also includes clinical primary outcomes. Breda's full methods are not supplied, so this supports the stated background only.

Evidence-Based High-Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross-Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial. (Introduction, discussion of progressive tendon-loading exercise; Reference 38; Primary Outcomes: Clinical Outcomes.)

The stated scientific basis also includes a meta-analysis of training studies in healthy adults; this evidence does not establish the optimal load for older patients with an injury.

Matches this study. The reference explicitly identifies Bohm and colleagues' systematic review and meta-analysis of exercise interventions in healthy adults. This verifies the stated background population, while providing no direct determination of optimal loading for older injured patients; the meta-analysis itself is not supplied in full.

Load magnitude affects patellar tendon mechanical properties but not collagen or collagen cross-linking after long-term strength training in older adults. (Background; Reference 12.)

The experiment tests preservation of the regenerative reserve of aged muscle progenitor cells using transplantation into muscle microtissues.

Different experimental conditions. Cosgrove and colleagues tested regenerative reserve and transplantation of aged mouse muscle stem cells into recipient mouse muscles. Muscle microtissues were not the recipient system.

Rejuvenation of the aged muscle stem cell population restores strength to injured aged muscles (Results: Expanded aged MuSC population has enhanced long-term function; Figures 5 and 6; Online Methods: MuSC transplantation.)

Early exit from quiescence during graft preparation may prematurely exhaust aged muscle progenitor cells and reduce their regenerative reserve for a second injury.

Different experimental conditions. Chakkalakal and colleagues linked loss of quiescence in aged muscle to stem-cell depletion and impaired regeneration through niche-derived FGF2 signaling. They tested chronic changes in the native niche, rather than early activation during graft preparation followed by a second injury.

The aged niche disrupts muscle stem cell quiescence (Results: Aged satellite cells cycle more frequently during homeostasis; Longer-term changes in FGF signalling levels mediate satellite cell number and function; Figures 1, 4 and 5.)

After expansion and before transplantation, aged muscle progenitor cultures undergo a brief, reversible return to quiescence, described as low mitotic activity, which is expected to preserve their reserve and improve the repeated regenerative response.

Different experimental conditions. Oncostatin M induced reversible cell-cycle exit and preserved transplantation capacity in cells from 8-12-week-old mice. Reversibility was tested by switching culture conditions, but transplantation experiments did not establish the proposed brief post-expansion quiescence step in aged cells.

Induction of muscle stem cell quiescence by the secreted niche factor Oncostatin M (Results: Regulation of muscle stem cell quiescence by OSM; OSM treatment maintains stemness in vitro; Figures 1e, 2e and 3; Methods: Mice.)

Cultures with the brief reversible quiescence period are compared with cultures without this period on the same elastic substrate.

Different experimental conditions. The Oncostatin M experiments used uncoated plastic throughout, including long-term cultures. This differs from comparing the specified brief quiescence period against its omission on the same elastic substrate.

Induction of muscle stem cell quiescence by the secreted niche factor Oncostatin M (Methods: Stem cell purification and culture; Figures 1-3.)

Pretransplantation viability is equal between conditions, and equal numbers of live labeled cells are introduced into muscle microtissues from the same donor.

Different experimental conditions. Equal counted cell transplants and donor-cell reporters were used in mouse muscle. Equal pretransplantation viability between conditions was not established, and transplantation into same-donor muscle microtissues was absent.

Induction of muscle stem cell quiescence by the secreted niche factor Oncostatin M (Results: A secretomic screen for muscle stem cell regulators; OSM treatment maintains stemness in vitro; Figures 1e and 3; Methods: Muscle stem cell transplantation and muscle injury.)

The experimental injury sequence includes a first and a second injury so that regenerative reserve can be assessed during a repeated regenerative response.

Different experimental conditions. Two rounds of cardiotoxin injury were performed after Oncostatin M receptor deletion in young adult mice. This establishes a repeated-injury component, but in a different age group and intervention, without aged-cell transplantation into microtissues.

Induction of muscle stem cell quiescence by the secreted niche factor Oncostatin M (Results: Functions of OSM signaling in vivo; Figure 4c-e; Methods: Mice.)

The brief quiescence condition is predicted to increase donor-cell contribution to new muscle fibers after the second injury relative to the condition without this quiescence period.

Different experimental conditions. Oncostatin M-treated cells formed donor-derived fibers and retained regenerative activity after transplantation and cardiotoxin challenge. These experiments did not compare donor-derived new fibers after a second injury between the specified aged-cell quiescence and control conditions.

Induction of muscle stem cell quiescence by the secreted niche factor Oncostatin M (Results: A secretomic screen for muscle stem cell regulators; OSM treatment maintains stemness in vitro; Figures 1e and 3b; Supplementary Figure 2a described in Results.)

Tissue contraction force is a main outcome and is predicted to increase with the brief quiescence condition.

Different experimental conditions. Contractile force improved after transplantation of aged cells expanded with p38α/β inhibition on soft hydrogel. The intervention promoted expansion rather than a subsequent brief quiescence period, and force was measured in injured mouse muscle rather than microtissues.

Rejuvenation of the aged muscle stem cell population restores strength to injured aged muscles (Results: Rejuvenated aged MuSC population restores strength to aged muscles; Figure 6f-h; Online Methods: In vivo force measurements.)

An effect explained solely by higher initial survival would refute the prediction.

Not verified in the article. No supplied study establishes whether the benefit of the specified aged-cell quiescence treatment persists after accounting for initial survival. Equal cell counts and viability observations in other comparisons do not verify this decisive control.

An effect that disappears by the second injury would refute the prediction.

Not verified in the article. No supplied study tests whether the benefit of the specified brief quiescence treatment in aged-cell microtissue grafts disappears by the second injury. Serial transplantation and repeated injury under other interventions do not establish this criterion.

The stated scientific rationale is experimental evidence that substrate elasticity regulates skeletal muscle stem-cell self-renewal in culture.

Matches this study. Cosgrove and colleagues experimentally demonstrated that soft-substrate mechanics, together with p38α/β inhibition, regulate aged muscle stem-cell maintenance and regenerative function. They also cite Gilbert's elasticity study, although Gilbert's original full article is not supplied.

Rejuvenation of the aged muscle stem cell population restores strength to injured aged muscles (Results: p38α/β inhibition and hydrogel synergistically affect aged MuSC fates; Regenerative potential of aged MuSC populations is restored; Figures 3g-j and 4a-c; reference 30.)

The proposed experiment compares young and old animals with cochlear injury caused by noise exposure.

Different experimental conditions. Young and middle-aged mice were compared, and aging animals were followed to 95 weeks, but this was an aging study without experimental noise injury. The noise-treatment study used young mice without an old comparison group.

Cochlear Neurotrophin-3 overexpression at mid-life prevents age-related inner hair cell synaptopathy and slows age-related hearing loss (Results, Figures 1 and 3; Experimental procedures 4.1-4.2.)

In the old cochlea, neurotrophin 3 (NT-3) administered after injury may restore the number of auditory synaptic contacts before the accuracy of signal transmission recovers.

Not verified in the article. Post-injury NT-3 increased synaptic counts alongside recovery of auditory brainstem response wave 1 in young mice. Earlier recovery of contacts than coding accuracy in the old cochlea was not tested.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Results, Synaptic regeneration and functional recovery of suprathreshold responses; Figures 3, 5 and 6.)

Full signal transmission in noise is hypothesized to require restoration of the responses of auditory fibers with different dynamic ranges, because accurate coding depends on the composition of functional inputs.

Not verified in the article. Population responses to amplitude-modulated tones improved after NT-3 gene delivery, and the discussion invokes fibers with low spontaneous rates. Necessity of restoring the composition of dynamic-range responses for coding in masking noise was not tested.

AAV-mediated NT-3 overexpression protects cochleae against noise-induced synaptopathy (Results, Figures 3-4; Discussion, interpretation of amplitude-modulated responses and low-spontaneous-rate fibers.)

The alternative explanation is that the total number of morphological synaptic contacts is a sufficient predictor of sound coding in noise.

Not verified in the article. Synaptic counts correlated with auditory brainstem response wave 1 amplitudes, but this does not test whether counts alone sufficiently predict coding accuracy in masking noise independently of fiber-response composition.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Figure 6; Methods, Statistical analysis.)

Animals must receive the same sound dose before treatment allocation.

Different experimental conditions. Noise-exposed groups received the same 8-16 kHz exposure at 98 dB for 2 hours, but random assignment preceded exposure. The proposed sequence requires exposure before treatment allocation.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Methods, Animals and experimental design; Noise exposure.)

After injury, young and old animals must be randomized to NT-3 or vehicle, providing an NT-3 group and a vehicle group in each age category.

Different experimental conditions. Young male mice received NT-3 or poloxamer vehicle 24 hours after injury, but allocation occurred before injury and there were no corresponding old-animal treatment groups.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Methods, Animals and experimental design; Round-window administration of NT-3.)

A control cohort must establish the initial loss following injury.

Matches this study. Control and NT-3-overexpressing cohorts were examined 2 hours after noise to establish initial synaptic loss and compared with 14-day cohorts. This control was performed in a different transgenic experiment, not the complete proposed age-stratified treatment test.

Neurotrophin-3 regulates ribbon synapse density in the cochlea and induces synapse regeneration after acoustic trauma (Results, Figure 7 and Table 2; Materials and methods, Immunostaining, hair cell and synaptic counts.)

The experiment must verify the dose and hair-cell preservation; the original proposal does not specify which dose this verification concerns.

Matches this study. Sound levels were verified before each exposure, NT-3 formulations and injected volume were specified, and hair-cell survival was counted. This matches dose checking for acoustic exposure; actual intracochlear NT-3 exposure remained uncertain.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Methods, Noise exposure, NT-3 Formulation, Synapse and hair cell counts; Figure 1F-G.)

The primary outcome is the accuracy of coding a specified signal in masking noise, measured in individual auditory fibers after 4 weeks, with the animal as the unit of analysis.

Different experimental conditions. Functional measurements used compound auditory-nerve responses to clicks, tone bursts and amplitude-modulated tones 2 weeks after injury. They did not measure single-fiber coding of a specified signal in masking noise at 4 weeks with animal-level analysis.

AAV-mediated NT-3 overexpression protects cochleae against noise-induced synaptopathy (Results, Figures 3-4; Materials and methods, Subjects and general procedures; Physiological tests.)

The density of pairs of synaptic markers and the hearing threshold must be assessed as independent comparisons.

Matches this study. Hearing thresholds were assessed separately from the number of juxtaposed presynaptic and postsynaptic marker pairs per inner hair cell. These measurements match the proposed comparison measures, although the specified primary coding outcome was absent.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Figures 1-4; Methods, Cochlear function testing; Synapse and hair cell counts.)

The decisive comparison concerns already formed contacts: if coding accuracy in noise differs according to the composition of fiber responses at the same contact count, simple contact counting is insufficient.

Not verified in the article. None of the supplied studies compares coding accuracy in masking noise across different fiber-response compositions while holding the number of already formed contacts equal.

The additional hypothesis is rejected if contact count predicts coding with the specified accuracy independently of response composition.

Not verified in the article. The supplied studies do not test the rejection criterion that contact count predicts coding with the specified accuracy independently of response composition.

A wide interval associated with a small number of animals does not constitute refutation of the hypothesis.

Not verified in the article. The supplied studies do not apply the proposed rule distinguishing an inconclusive wide interval from refutation of this hypothesis. Their significance tests do not establish that rule.

The stated experimental background is that local NT-3 after noise injury in animal models increased synaptic contact counts and improved the first wave of the auditory response, while restoration of the composition of functional inputs needed for coding in noise remains unresolved.

Matches this study. Local NT-3 delivered after noise injury increased synaptic counts and improved auditory brainstem response wave 1. The study leaves restoration of functional-input composition for coding in noise unresolved.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Results, Figures 3 and 5-6; Discussion, Application to Human Hearing Impairment.)

The related hypothesis used for comparison proposes that NT-3 restores an auditory synapse while the neuronal process remains near the hair cell and predicts contact formation from the distance to that process.

Not verified in the article. The discussion considers peripheral-terminal regeneration and surviving hair-cell targets, but the study does not measure process-to-hair-cell distance as a predictor of NT-3-induced contact formation.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Discussion, Regeneration vs. Repair of Hair Cells and Synapses.)

The cited primary study concerns delivery of neurotrophin 3 through the round window to regenerate cochlear synapses after acoustic overexposure.

Matches this study. The bibliographic title matches the supplied primary article, which tests round-window NT-3 delivery after acoustic overexposure and reports synaptic regeneration with auditory-response recovery.

Round-window delivery of neurotrophin 3 regenerates cochlear synapses after acoustic overexposure (Article title; Methods, Round-window administration of NT-3; Figures 3 and 5.)

The proposed experiment has not yet produced results.

Not verified in the article. The proposal states that its experiment has not produced results. The supplied literature contains no results from that complete experiment; this contextual statement is not itself an empirical novelty finding.

The hypothesis concerns the size-dependent functional benefit of reassembled islets during aging and requires separate testing in older adult islets.

Different experimental conditions. Size-dependent function was tested in pseudo-islets from 9-12-week-old male Lewis rats, rather than in an aging model with a separate older-adult islet experiment.

Size effect of engineered islets prepared using microfabricated wells on islet cell function and arrangement (Methods 2.1; Results 3.1-3.4)

The stated background is that assembling endocrine cells derived from human stem cells into clusters improved functional maturation and glucose responsiveness.

Not verified in the article. The supplied articles do not directly test improved maturation and glucose responsiveness through clustering human stem-cell-derived endocrine cells. References to stem-cell studies provide background only.

Increasing contacts between beta cells may improve function until an oxygen gradient produces oxygen deficiency at the aggregate center, limiting the benefit of further increases in reassembled islet size.

Not verified in the article. Larger reassembled rat islets had more central hypoxia, and small aggregates had better glucose-stimulated secretion at day 7. The complete causal sequence from increased beta-cell contacts to an oxygen-limited functional benefit was not tested.

Size effect of engineered islets prepared using microfabricated wells on islet cell function and arrangement (Results 3.2-3.4; Figures 3-5; Discussion)

Cells from the same donor must be distributed into clusters of two sizes.

Not verified in the article. Dispersed rat islet cells were reassembled into three size classes, but the methods do not establish that each individual donor supplied the compared size conditions.

Size effect of engineered islets prepared using microfabricated wells on islet cell function and arrangement (Methods 2.1-2.3; Figure 2)

The two cluster-size conditions must have equal total cell mass and matched cell-type composition.

Not verified in the article. Equal cell numbers were seeded, and alpha- and beta-cell proportions showed no significant differences at day 7. Equal total cell mass and experimentally matched complete cell-type composition were not established.

Size effect of engineered islets prepared using microfabricated wells on islet cell function and arrangement (Methods 2.3 and 2.7; Results 3.3; Figure 4G)

Normal and enhanced oxygen delivery must be compared at both cluster sizes, with oxygen supply improved independently of the increase in beta-cell contacts.

Different experimental conditions. Oxygen concentration was varied independently across naturally sized intact human islets. This substitutes intact islets for donor-matched reassembled clusters in the specified two-size oxygen-delivery experiment.

Oxygen environment and islet size are the primary limiting factors of isolated pancreatic islet survival (Methods, Human islet culture under different oxygen concentrations; Figures 2C-D and 3D-E)

Intratissue oxygen must be measured to verify the effect of the oxygen-delivery intervention.

Different experimental conditions. Oxygen was measured in culture medium, while oxygen inside islets was simulated. These measurements do not verify intratissue oxygen equalization after the proposed intervention.

Oxygen environment and islet size are the primary limiting factors of isolated pancreatic islet survival (Methods, Absolute oxygen tension in media under various oxygen settings; Computational simulation; Figures 1D and 2C)

The experiment must be repeated with young and older donors.

Not verified in the article. No supplied study reports the specified reassembly and oxygen-delivery experiment repeated in young and older donor groups.

The primary outcome is glucose-stimulated insulin release normalized to the initial viable beta-cell mass.

Different experimental conditions. Glucose-stimulated insulin secretion was normalized to DNA content or WST-8 metabolic activity, rather than to initial viable beta-cell mass.

Size effect of engineered islets prepared using microfabricated wells on islet cell function and arrangement (Methods 2.8; Results 3.4; Figure 5)

The primary outcome must be assessed after an identical maturation period across experimental conditions.

Matches this study. The size groups were compared at common culture durations, separately at days 7 and 14. This matches the timing requirement alone; the specified oxygen-delivery and age conditions were absent.

Size effect of engineered islets prepared using microfabricated wells on islet cell function and arrangement (Results 3.4; Figure 5A-D)

Enhanced oxygen delivery is predicted to shift the dependence of the primary outcome on cluster size and thereby shift the optimal reassembled islet size.

Different experimental conditions. Oxygenation altered size-related viability and predicted survival of intact human islets. A shift in optimal reassembled-islet size defined by secretion per initial viable beta-cell mass was not assessed.

Oxygen environment and islet size are the primary limiting factors of isolated pancreatic islet survival (Results, Islet viability as a function of islet diameter and medium oxygen tension; Figure 3D-E)

If confirmed oxygen equalization leaves the size dependence unchanged, oxygen limitation does not explain the shape of the recovery curve.

Not verified in the article. No supplied study tests whether the functional size dependence persists after experimentally confirmed intratissue oxygen equalization.

The islet donor must be the independent experimental unit.

Different experimental conditions. The survival analysis used individual islets, with donor identity included for donor-specific predictions. It does not establish donors as independent experimental units for the proposed paired functional comparison.

Oxygen environment and islet size are the primary limiting factors of isolated pancreatic islet survival (Methods, Islet viability assay and Data analysis; Figure 3D-E)

Samples must be randomly assigned to experimental conditions.

Not verified in the article. Random assignment to the proposed experimental conditions is not documented. Random selection of microscopy fields in the rat study does not establish randomized treatment allocation.

The outcome must be assessed blinded to experimental condition.

Not verified in the article. The supplied methods do not document outcome assessment blinded to experimental condition.

The conclusion must remain indeterminate if the intervention fails to engage its target or if the interval permits both explanations.

Not verified in the article. No supplied study applies the specified indeterminate-conclusion rule based on failed oxygen target engagement or an interval compatible with both mechanistic explanations.

The experiment is intended to determine whether oxygen transport or the geometry of intercellular contacts should be optimized during islet assembly, with the prediction restricted to the model studied.

Not verified in the article. The device study relates oxygen supply to encapsulated-islet packing density and device design. It does not experimentally distinguish oxygen transport from beta-cell contact geometry during reassembly.

Long-term viability and function of transplanted islets macroencapsulated at high density are achieved by enhanced oxygen supply (Results, Minimum required gas chamber pO2; Discussion; Figure 3)

In the aged periodontal ligament, fiber orientation may be more important for mechanical recovery than the amount of new cementum, because a tooth can acquire a mineralized root covering after injury while still poorly damping chewing loads.

Not verified in the article. The supplied studies do not test whether fiber orientation outweighs cementum quantity as a determinant of mechanical recovery in aged periodontal ligament.

If periodontal ligament fiber orientation limits function, a guiding scaffold is expected to improve fiber orientation and elastic recoil at the same amount of new cementum.

Not verified in the article. Aligned scaffolds improved ligament orientation and periostin expression, but improved elastic recoil at equal cementum quantity was not tested.

Gelatin-assisted conglutination of aligned polycaprolactone nanofilms into a multilayered fibre-guiding scaffold for periodontal ligament regeneration (Results 3.6.1-3.6.2; Figures 7-9)

The stated preclinical background is that microstructured scaffolds guiding the formation of bone and periodontal-like tissue have been tested.

Matches this study. Microstructured zonal scaffolds with aligned ligament compartments and mineral-coated bone compartments were implanted into rat periodontal defects and supported bone and periodontal ligament regeneration.

Tissue-specific melt electrowritten polymeric scaffolds for coordinated regeneration of soft and hard periodontal tissues (Methods 2.11-2.13; Results and discussion 3.5; Figures 8-10)

The experiment must use paired periodontal defects in young and old animals.

Different experimental conditions. The study created bilateral defects in 8-week-old rats. It lacked an old-animal group and did not establish a within-animal paired comparison of the two scaffold orientations.

Gelatin-assisted conglutination of aligned polycaprolactone nanofilms into a multilayered fibre-guiding scaffold for periodontal ligament regeneration (Methods 2.6.1)

The experiment must compare an oriented scaffold with a scaffold with random orientation.

Matches this study. The in vivo experiment directly compared three-dimensional aligned and random scaffolds, alongside an empty-defect control.

Gelatin-assisted conglutination of aligned polycaprolactone nanofilms into a multilayered fibre-guiding scaffold for periodontal ligament regeneration (Methods 2.1.2 and 2.6.1; Results 3.6.1; Figure 7)

The compared scaffolds must have the same chemistry, stiffness and number of cells.

Not verified in the article. Both scaffold types used polycaprolactone and gelatin, and equal seeding densities were specified for in vitro assays. Equal scaffold stiffness and equal implanted cell numbers were not established.

Gelatin-assisted conglutination of aligned polycaprolactone nanofilms into a multilayered fibre-guiding scaffold for periodontal ligament regeneration (Methods 2.1.1-2.1.3, 2.3-2.4 and 2.6.1)

Periodontal ligament fiber angle must be measured to assess fiber orientation.

Matches this study. Regenerated ligament angulation relative to the root surface was quantified histologically using nuclear and cell arrangement as the orientation readout.

Gelatin-assisted conglutination of aligned polycaprolactone nanofilms into a multilayered fibre-guiding scaffold for periodontal ligament regeneration (Results 3.6.1; Figure 7; Table 1)

Cementum volume must be measured.

Different experimental conditions. Micro-computed tomography quantified alveolar bone volume, bone fill and tissue mineral density. These measurements concern bone rather than cementum volume.

Tissue-specific melt electrowritten polymeric scaffolds for coordinated regeneration of soft and hard periodontal tissues (Methods 2.12; Results and discussion 3.5; Figure 9)

Areas of contact between bone and the tooth root must be measured.

Not verified in the article. Histological descriptions of ligament space and tissue interfaces do not establish quantified areas of direct bone-root contact.

Baseline chewing load must be measured.

Not verified in the article. None of the supplied full articles reports measurement of baseline chewing load for the experimental animals.

The primary outcome is the fraction of reversible tooth displacement after a standard loading cycle at a fixed maturation stage, and this fraction is predicted to increase with the oriented scaffold.

Different experimental conditions. Function at 4 weeks was assessed indirectly through periostin and decorin staining. The study explicitly deferred direct biomechanical assessment and did not measure reversible tooth displacement after a loading cycle.

Spatial Platform for Periodontal Ligament Angulation and Regeneration: In Vivo Pilot Study (Methods 2.5; Results 3.3; Discussion 4; Figure 5)

Improved fiber orientation without increased elastic recoil, at matched mineral volume and in the absence of ankylosis, would show that directed assembly did not remove the functional limitation.

Not verified in the article. No supplied experiment combines improved orientation, measured recoil, matched mineral volume and exclusion of ankylosis to test the proposed falsification criterion.

The independent experimental unit must be the animal or the periodontal ligament donor.

Different experimental conditions. The angular analysis defines its sample count as sites, with bilateral defects and four rats per group per time point. Animal-level independence or adjustment for within-animal clustering is not established.

Gelatin-assisted conglutination of aligned polycaprolactone nanofilms into a multilayered fibre-guiding scaffold for periodontal ligament regeneration (Methods 2.6.1 and 2.7; Table 1)

Samples must be randomly assigned to experimental conditions.

Not verified in the article. Random allocation to experimental conditions is not documented. Random scaffold orientation and random selection of microscopy fields or scaffold features do not establish treatment randomization.

The outcome must be assessed blind to the experimental condition.

Not verified in the article. Blinding of outcome assessment to experimental condition is not documented in the supplied full articles.

The conclusion must remain indeterminate if the intervention did not reach its target or if the interval permits both explanations.

Not verified in the article. The studies do not specify an indeterminate conclusion when orientation guidance fails or when an interval remains compatible with both mechanistic explanations.

The experiment is intended to determine whether making scaffold geometry more complex is worthwhile; it does not predict how long a patient's tooth will be retained.

Not verified in the article. The articles evaluate scaffold-guided regeneration, but do not implement the specified mechanical decision test for whether added geometric complexity is worthwhile. They provide no patient tooth-retention prediction.