Medical student self-efficacy, knowledge and communication in adolescent medicine

Objectives To evaluate student self-efficacy, knowledge and communication with teen issues and learning activities. Methods Data were collected during the 8-week pediatric rotation for third–year medical students at a local children’s hospital. Students completed a self-efficacy instrument at the beginning and end of the rotation; knowledge and communication skills were evaluated during standardized patient cases as part of the objective structured clinical examination. Self-efficacy, knowledge and communication frequencies were described with descriptive statistics; differences between groups were also evaluated utilizing two-sample t-tests. Results Self-efficacy levels of both groups increased by the end of the pediatric rotation, but students in the two-lecture group displayed significantly higher self-efficacy in confidentiality with adolescents (t(35)=-2.543, p=0.02); interviewing adolescents, assessing risk, sexually transmitted infection risk and prevention counseling, contraception counseling were higher with marginal significance. No significant differences were found between groups for communication; assessing sexually transmitted infection risk was marginally significant for knowledge application during the clinical exam. Conclusions Medical student self-efficacy appears to change over time with effects from different learning methods; this higher self-efficacy may increase future comfort and willingness to work with this high-risk, high-needs group throughout a medical career

Subsequent cultivation of chondrocytes and mesenchymal stem cells on the devitalised tissue

The regeneration of cartilage lesions still represents a major challenge. Cartilage has a tissue-specific architecture, complicating recreation by synthetic biomaterials. A novel approach for reconstruction is the use of devitalised cartilage. Treatment with high hydrostatic pressure (HHP) achieves devitalisation while biomechanical properties are remained. Therefore, in the present study, cartilage was devitalised using HHP treatment and the potential for revitalisation with chondrocytes and mesenchymal stem cells (MSCs) was investigated. The devitalisation of cartilage was performed by application of 480 MPa over 10 minutes. Effective cellular inactivation was demonstrated by the trypan blue exclusion test and DNA quantification. Histology and electron microscopy examinations showed undamaged cartilage structure after HHP treatment. For revitalisation chondrocytes and MSCs were cultured on devitalised cartilage without supplementation of chondrogenic growth factors. Both chondrocytes and MSCs significantly increased expression of cartilage- specific genes. ECM stainings showed neocartilage-like structure with positive AZAN staining as well as collagen type II and aggrecan deposition after three weeks of cultivation. Our results showed that HHP treatment caused devitalisation of cartilage tissue. ECM proteins were not influenced, thus, providing a scaffold for chondrogenic differentiation of MSCs and chondrocytes. Therefore, using HHP-treated tissue might be a promising approach for cartilage repair

Theoretical study of peculiarities of unstable longitudinal shear crack growth in sub-Rayleigh and supershear regimes

In the paper we present the results of the theoretical study of some fundamental aspects of mode II crack propagation in conventional sub-Rayleigh regime and transition to intersonic regime. It is shown that development of a sub-Rayleigh shear crack is determined in many respects by elastic vortex traveling ahead of the crack tip at a shear wave velocity. Formation of such a vortex helps to better understand the well-known phenomenon of acceleration of a shear crack towards the longitudinal wave velocity. Simulation results have shown that due to self-similarity of shear crack propagation the conditions of sub-Rayleigh to intersonic transition depend on dimensionless material and crack parameters. Two key dimensionless parameters are proposed