Applying Similitude Modeling Methods to Tribological Applications

Tribology is a field encompassing topics such as friction, wear, and lubrication. Because tribological principles often act on small scales, gathering accurate data can be difficult. The objective of this research was to scale up tests to measure wear on a macroscopic scale. Similitude is a method often used in scaling fluid dynamics problems where testing parameters are calculated from dimensionless values. By applying the Buckingham Pi Theorem to a simple wear test, seven dimensionless terms were determined. Intermolecular surface forces impact wear but do not adjust with the system size, so they were modeled by magnetic forces. Iron oxide powder was mixed with paraffin wax to create magnetic wax samples, and magnets of varying strengths were placed under a macroscopically textured counterface. Wear tests were conducted using a tribometer, holding constant the distance, velocity, plate roughness, materials, contact area, and applied load, while the magnetic force was varied between tests. The total wear amount was measured, and the results were then analyzed to determine a dimensionless relationship between surface forces and wear. Future research should include measuring how changing other parameters impact wear, which could allow for the implementation of similitude modeling in various tribology applications

Distinct Wnt-driven primitive streak-like populations reflect in vivo lineage precursors

During gastrulation, epiblast cells are pluripotent and their fate is thought to be constrained principally by their position. Cell fate is progressively restricted by localised signalling cues from areas including the primitive streak. However, it is unknown whether this restriction accompanies, at the individual cell level, a reduction in potency. Investigation of these early transition events in vitro is possible via the use of epiblast stem cells (EpiSCs), self-renewing pluripotent cell lines equivalent to the postimplantation epiblast. Strikingly, mouse EpiSCs express gastrulation stage regional markers in self-renewing conditions. Here, we examined the differentiation potential of cells expressing such lineage markers. We show that undifferentiated EpiSC cultures contain a major subfraction of cells with reversible early primitive streak characteristics, which is mutually exclusive to a neural-like fraction. Using in vitro differentiation assays and embryo grafting we demonstrate that primitive streak-like EpiSCs are biased towards mesoderm and endoderm fates while retaining pluripotency. The acquisition of primitive streak characteristics by self-renewing EpiSCs is mediated by endogenous Wnt signalling. Elevation of Wnt activity promotes restriction towards primitive streak-associated lineages with mesendodermal and neuromesodermal characteristics. Collectively, our data suggest that EpiSC pluripotency encompasses a range of reversible lineage-biased states reflecting the birth of pioneer lineage precursors from a pool of uncommitted EpiSCs similar to the earliest cell fate restriction events taking place in the gastrula stage epiblast

Corrigendum to “Adult attachment and prolonged grief:A systematic review and meta-analysis” [Personality and Individual Differences 214 (2023) 112315] (Personality and Individual Differences (2023) 214, (S0191886923002386), (10.1016/j.paid.2023.112315))

Correction to Eisma et al. (2023) In the article “Adult attachment and prolonged grief: A systematic review and meta-analysis” by Maarten C. Eisma, Kathrin Bernemann, Lena Aehlig, Antje Janshen, and Bettina K. Doering (Personality and Individual Differences, 2023, Vol. 214: 112315. https://doi.org/10.1016/j.paid.2023.112315), an error occurred in the meta-analysis of the concurrent associations between attachment avoidance and prolonged grief symptoms. The error has not affected the general conclusions from the systematic review and meta-analysis. Nevertheless, the authors regret the error has occurred and hereby wish to correct it. The correlation coefficient between attachment avoidance and prolonged grief symptoms for the study by Delespaux (2013) was entered as r = 0.19 in the calculation of the meta-analysis. The correct coefficient is r = −0.21. The correction of this error resulted in changes in Section 3.3.4 of the results section, Figs. 3, 4 and Table 4. Meta-analysis of concurrent associations between attachment avoidance and prolonged grief symptoms The random effects model demonstrated a pooled correlation coefficient of small size between attachment avoidance and prolonged grief symptoms (r = 0.13; k = 15; 95 % CI: 0.01–0.24, Fig. 3). The LFK index was −1.00, with the Doi plot indicating no asymmetry (i.e., publication bias). Heterogeneity among studies was significant (Q = 206.88, p ≤ .001) with a very high I2 (93%). The subgroup analysis comparing studies that measured attachment avoidance in general (r = 0.23; k = 10; 95 % CI: 0.19–0.27; I2 = 30 %) and studies that measured attachment avoidance in relation to the deceased (r = −0.07; k = 5; 95 % CI: −0.31−0.19; I2 = 94 %) yielded a significant difference between the groups, Q(1) = 122.76, p ≤ .001 (Fig. 4). The sensitivity analysis identified three outliers as outside of the 95 % CI of the pooled correlation coefficient (Delespaux et al., 2013; Meert et al., 2010; Smigelsky et al., 2020). Table 4 presents the results of the MetaXL sensitivity analysis by showing the pooled correlation coefficient when each respective study is excluded. Removal of the three outliers increased the pooled correlation coefficient (r = 0.20; k = 12; 95 % CI: 0.15–0.24) and reduced heterogeneity (Q = 16.65, p = .119; I2 = 34 %). After removal of the outliers, the difference in the subgroup analysis comparing attachment assessments (attachment avoidance in general: r = 0.22; k = 9; 95 % CI: 0.18–0.25; I2 = 0 %; attachment avoidance in relation to the deceased: r = 0.11; k = 3; 95 % CI: −0.07-0.30; I2 = 72 %) was no longer significant (Q = 3.37, p = .066).[Figure</p

Adult attachment and prolonged grief:A systematic review and meta-analysis

Diagnoses characterized by severe, persistent and disabling grief have recently been added to the ICD-11 and DSM-5-TR as prolonged grief disorder. Adult attachment is widely assumed critical in the development, persistence, and treatment of prolonged grief, yet a meta-analysis on this topic is lacking. We conducted a systematic review (PROSPERO: CRD42021220511) searching PsycInfo, Web of Science, and PubMed (final search: August 2022) to identify and summarize quantitative research examining relationships between adult attachment (i.e., attachment anxiety, attachment avoidance, secure attachment, disorganized attachment) and prolonged grief symptoms. Thirty-one studies including 8347 bereaved adults were included. Attachment anxiety (r = 0.28, 95 % CI:0.23–0.32, k = 15) and attachment avoidance (r = 0.15, 95 % CI:0.05–0.26, k = 15) related positively to prolonged grief symptoms concurrently. We found no evidence of publication bias but did detect heterogeneity in effect sizes. Ten longitudinal analyses showed no evidence that insecure attachment styles increase prolonged grief symptoms. Attachment anxiety predicted better therapy outcomes. Insecure attachment styles are concurrently positively related to prolonged grief symptoms but do not increase grief severity. The role of adult attachment in contemporary grief theories may need reconsideration. Intensive longitudinal research should aim to clarify how dynamic changes in attachment to the deceased and others relate to changes in prolonged grief symptoms.</p

Humanbiobanken

Wie aus „sensiblen Daten“ „Big Data“ wird - Biobanken im Humanbereich sind Sammlungen von Proben menschlicher Körpersubstanzen (etwa Gewebe, Blut, genetisches Material), die mit sensiblen personenbezogenen Daten und insbesondere gesundheitsbezogenen Informationen über die Spender digital verknüpft sind. Sie stellen eine bedeutende Ressource für die biomedizinische Forschung dar, um Ursachen und Mechanismen zahlreicher Erkrankungen besser zu verstehen und deren Diagnose und Behandlung weiterzuentwickeln. Bei der Errichtung und Handhabung von Humanbiobanken sind das Interesse an medizinischer Forschung und die Forschungsfreiheit einerseits mit den Rechten und Interessen der Probenspender und Patienten andererseits in Einklang zu bringen. Daher werfen Biobanken ethische und rechtliche Fragen auf, die vom Schutz individueller Persönlichkeitsrechte bis hin zur globalen Regulierung von Forschungsinfrastrukturen reichen. Der Sachstandsbericht führt in dieses Gebiet ein und informiert über die biomedizinischen Grundlagen der Handhabung von Humanbiobanken, ihre rechtlichen Regelungen und die mit ihnen verbundenen ethischen Debatten.How “sensitive data” becomes “big data” - Human biobanks are collections of samples of human bodily substances (such as tissue, blood and genetic material) which are digitally linked to individual donor data and especially health-related information. Human biobanks constitute an essential resource for biomedical research on causes and mechanisms of numerous diseases and their diagnosis and treatment. In the building and management of human biobanks, the objectives of medical research and freedom of research are to be brought into accordance with the rights and interests of donors and patients. As a consequence, biobanks raise ethical and legal questions ranging from the protection of individual personal rights to the global regulation of research infrastructures. This expert report is an introduction to this field and informs about the biomedical basic principles of managing human biobanks, their legal regulations and the associated ethical debates

Comparison of circulating tumor cells and AR-V7 as clinical biomarker in metastatic castration-resistant prostate cancer patients

Abstract Biomarker in metastatic castration resistant prostate cancer (mCRPC) treatment are rare. We aimed to compare the clinical value of circulating tumor cells (CTCs) and androgen receptor splice variant 7 (AR-V7) as biomarker in mCRPC patients undergoing androgen receptor-targeted agent (ARTA) treatment. Overall cohort (65 patients) was stratified regarding either CTC or AR-V7 status followed by further sub-stratification of the respective other marker. Subsequently, prostate specific antigen (PSA) response, progression free survival (PFS) and overall survival (OS)) of subgroups was compared. CTCs and AR-V7 were detected in 54 (83%) and 33 (61%) patients, respectively. All AR-V7 + were CTC +. We detected PSA response in all subgroups. For PFS and OS, biomarker stratification revealed differences between all subgroups. Interestingly, no significant differences of AR-V7 transcript copy numbers were detected between responding and non-responding patients. Additionally, multivariable analysis revealed no independent prognostic value of AR-V7 positivity. Both biomarkers show clinical value in prognosticating clinical outcome. Nonetheless, AR-V7 stratification underestimates the heterogenous subgroup of CTC − and CTC + patient, the latter requiring more intense clinical surveillance. Additionally, AR-V7 level does not correlate with clinical response. Thus, the value of AR-V7 as a clinical biomarker must be considered skeptically