Self-perceptions as mechanisms of achievement inequality: evidence across 70 countries.

Children from lower socioeconomic status (SES) backgrounds tend to have more negative self-perceptions. More negative self-perceptions are often related to lower academic achievement. Linking these findings, we asked: Do children's self-perceptions help explain socioeconomic disparities in academic achievement around the world? We addressed this question using data from the 2018 Programme for International Student Assessment (PISA) survey, including n = 520,729 records of 15-year-old students from 70 countries. We studied five self-perceptions (self-perceived competency, self-efficacy, growth mindset, sense of belonging, and fear of failure) and assessed academic achievement in terms of reading achievement. As predicted, across countries, children's self-perceptions jointly and separately partially mediated the association between socioeconomic status and reading achievement, explaining additional 11% (ΔR2 = 0.105) of the variance in reading achievement. The positive mediation effect of self-perceived competency was more pronounced in countries with higher social mobility, indicating the importance of environments that "afford" the use of beneficial self-perceptions. While the results tentatively suggest self-perceptions, in general, to be an important lever to address inequality, interventions targeting self-perceived competency might be particularly effective in counteracting educational inequalities in countries with higher social mobility.

Assessing Emotion Regulation Strategies in Chile: A Spanish Language Adaptation of the German SSKJ 3-8 Scales.

The aim of the present study is the psychometric review of a Spanish language version of the German Stress and Coping Questionnaire for Children and Adolescents (SSKJ 3-8). The SSKJ 3-8 assesses emotion regulation strategies by asking children to indicate how often they use five different emotion regulation strategies in response to a social and an academic stress situation. The Spanish language adaptation of the inventory was developed for a cross-cultural study with Chilean and German fourth-graders. The sample includes 76 German and 169 Chilean fourth graders. The SSKJ 3-8 was first translated into Spanish by a bilingual translator, then back-translated by a German native speaker, and finally adapted for the cultural context in Chile. To analyze the psychometric comparability, the measurement invariance was examined within the framework of the Item Response Theory (IRT) with the R package pairwise. The results show that the new developed Spanish language adaptation of the SSKJ 3-8 is comparable to the German version in terms of psychometric measurement characteristics. Only few items show deviations with regard to strong measurement invariance. We conclude that the Spanish language adaptation of the SSKJ 3-8 is a reliable instrument to assess emotion regulation strategies in Chile.

Nerve regeneration techniques respecting the special characteristics of the inferior alveolar nerve.

PURPOSE: The aim of this study was to examine the in situ regeneration of the inferior alveolar nerve (IAN) in its bony channel, using autologous tissue in combination with a recombinant human nerve growth factor (rhNGF). MATERIALS AND METHODS: A total of 20 New Zealand rabbits were randomly divided into five groups. Following dissection of the IAN, the animals underwent reconstruction either with muscle tissue (groups 1 and 2) or with fat tissue (groups 3 and 4). In group 5 (control), the dissected nerve was resected and reconstructed by placement of the reversed autologous segment. After 2 and 4 weeks, 1 mL rhNGF was locally injected in groups 1 and 3. Nerve function was monitored by measuring the jaw-opening reflex using electromyography for a period of 24 weeks. RESULTS: Regeneration of the nerve was achieved in all groups, but preoperative threshold values were not achieved. Comparing the experimental groups to the control, there was a significant difference in favor of the autologous nerve reconstruction. Differences between the experimental groups remained statistically not significant. CONCLUSION: Regeneration of the IAN with autologous tissue is possible, but without achieving preoperative thresholds. Additional injection of a growth factor seems to improve the speed of regeneration for fat and muscle grafts.

Tissue engineering human small-caliber autologous vessels using a xenogenous decellularized connective tissue matrix approach: preclinical comparative biomechanical studies.

Suggesting that bioartificial vascular scaffolds cannot but tissue-engineered vessels can withstand biomechanical stress, we developed in vitro methods for preclinical biological material testings. The aim of the study was to evaluate the influence of revitalization of xenogenous scaffolds on biomechanical stability of tissue-engineered vessels. For measurement of radial distensibility, a salt-solution inflation method was used. The longitudinal tensile strength test (DIN 50145) was applied on bone-shaped specimen: tensile/tear strength (SigmaB/R), elongation at maximum yield stress/rupture (DeltaB/R), and modulus of elasticity were determined of native (NAs; n = 6), decellularized (DAs; n = 6), and decellularized carotid arteries reseeded with human vascular smooth muscle cells and human vascular endothelial cells (RAs; n = 7). Radial distensibility of DAs was significantly lower (113%) than for NAs (135%) (P < 0.001) or RAs (127%) (P = 0.018). At levels of 120 mm Hg and more, decellularized matrices burst (120, 160 [n = 2] and 200 mm Hg). Although RAs withstood levels up to 300 mm Hg, ANOVA revealed a significant difference from NA (P = 0.018). Compared with native vessels (NAs), SigmaB/R values were lower in DAs (44%; 57%) (P = 0.014 and P = 0.002, respectively) and were significantly higher in RAs (71%; 83%) (both P < 0.001). Similarly, DeltaB/R values were much higher in DAs compared with NAs (94%; 88%) (P < 0.001) and RAs (87%; 103%) (P < 0.001), but equivalent in NAs and RAs. Modulus of elasticity (2.6/1.1/3.7 to 16.6 N/mm(2)) of NAs, DAs, RAs was comparable (P = 0.088). Using newly developed in vitro methods for small-caliber vascular graft testing, this study proved that revitalization of decellularized connective tissue scaffolds led to vascular graft stability able to withstand biomechanical stress mimicking the human circulation. This tissue engineering approach provides a sufficiently stable autologized graft.

Preclinical assessment of a tissue-engineered vasomotive human small-calibered vessel based on a decellularized xenogenic matrix: histological and functional characterization.

OBJECTIVES: Tissue-engineered arterial vessels (TEAV) offer substantial advantages in small-calibered human-bypass-grafting and vascularized scaffold applications. However, histological composition of TEAV must allow for functional properties, such as vasomotoricity. Aim of this study was to characterize human TEAVs regarding morphology and vasomotoricity. METHODS: Three groups containing segments of porcine carotid artery < 5 mm in diameter (native [NA, n = 6], decellularized [DA, n = 6], and decellularized/reseeded in a bioreactor [RA, n = 7] with human vascular endothelial [hvECs] and smooth muscle cells [hvSMCs]) were examined. Light and scanning electron microscopy were applied, and hvSMCs- and hvECs-associated Vasomotoricity Test conducted in Krebs-solution was used for characterization of revitalized TEAVs. RESULTS: Morphologic examination showed cell-free extracellular matrix in DAs. Light microscopy demonstrated intact extracellular matrix components in circle-layered formation in cross sections of DAs. RAs showed small cells migrating along the remaining medial fiber structures and flat cell layers at the luminal site, identified as hvECs and hvSMCs with lower CD-31 and α-actin signaling than controls. Scanning electron microscopy showed intact flat cell layers on luminal surfaces of RAs and dense hvSMCs at their media site. DAs showed decreasing strain after stimulation. RAs retrieved vasomotoricity compared to DAs, but showed reduced contraction and incomplete relaxation compared to NAs. CONCLUSIONS: This study shows that revitalization of DA with human vascular cells resembles NA-like morphology and can ensure vasomotoricity of TEAVs.