Hofmeister Effects in Membrane Biology: The Role of Ionic Dispersion Potentials

The Hofmeister effects in membrane biology were studied. The influence of ionic dispersion potentials on the binding of peptides to memebranes was also demonstrated. It was shown that the large attractive ionic disperion potentials acting on anions at biological concentrations result in negative interfacial tension changes. It was shown why the ionic dispersion potential near an oil-water interface was similar to the chemical potential of different n-alkanes

Case report: Good prognosis in leiomyosarcoma of the kidney

The Casimir-Polder force is an important long-range interaction involved in adsorption and desorption of molecules in fluids. We explore Casimir-Polder interactions between methane molecules in water, and between a molecule in water near SiO2 and hexane surfaces. Inclusion of the finite molecular size in the expression for the Casimir-Polder energy leads to estimates of the dispersion contribution to the binding energies between molecules and between one molecule and a planar surface

Mechanical instability induces osteoclast differentiation independent of the presence of a fibrous tissue interface and osteocyte apoptosis in a rat model for aseptic loosening

Background and purpose - Insufficient initial fixation or early micromotion of an implant is associated with a thin layer of fibrous tissue at the peri-implant interface. It is unknown if bone loss is induced by the fibrous tissue interface acting as an active biological membrane, or as a membrane that will produce supraphysiologic fluid flow conditions during gait, which activates the mechanosensitive osteocytes to mediate osteoclast differentiation. We investigated whether mechanically induced osteolysis is dependent on the fibrous tissue interface as a biologically active scaffold, or if it merely acts as a conduit for fluid flow, affecting the mechanosensitive osteocytes in the peri-prosthetic bone. Methods - Using a rat model of mechanically instability-induced aseptic loosening, we assessed whether the induction of osteoclast differentiation was dependent on the presence of a peri-implant fibrous interface. We analyzed the amount of osteoclast differentiation, osteocyte apoptosis, pro-resorptive cytokine expression and bone loss using immunohistochemistry, mRNA expression and micro-CT. Results - Osteoclast differentiation and bone loss were induced by mechanical instability but were not affected by the presence of the fibrous tissue membrane or associated with osteocyte apoptosis. There was no increased mRNA expression of any of the cytokines in the fibrous tissue membrane compared with the peri-implant bone. Interpretation - Our data show that the fibrous tissue membrane in the interface plays a minor role in inducing bone loss. This indicates that the peri-implant bone adjacent to loose bone implants might play an important role for osteoclast differentiation

Comparative Assessment of Grit, Conscientiousness, and Self-Control in Applicants Interviewing for Residency Positions and Current Orthopaedic Surgery Residents.

OBJECTIVE: The purpose of this study was to quantify grit, conscientiousness, and self-control in orthopaedic residency applicants and current orthopaedic surgery residents. As part of a continual reassessment of the selection process, this study will help to improve this process by assessing the introduction of these non-cognitive assessments. This is the first study to both evaluate and compare the applicants\u27 scores to those of current residents. This introduction will allow selection of not only the current top performers but those who have the wherewithal (read grit) to sustain their efforts throughout their residency. DESIGN: A cross-sectional study composed of a confidential electronic survey consisting of a 17-item Grit scale, 10-item Self-control scale, and 9-item Conscientiousness scale was completed by medical school applicants and orthopaedic residents. SETTING: Department of Orthopaedic Surgery, Hospital for Special Surgery. PARTICIPANTS: Fifty-six (100%) medical student applicants (mean age = 27) were invited to participate in our study following a full day of interviews. Forty-five residents (mean age = 31) were asked and 32 (72%) completed the same surveys 4 months later. RESULTS: There was a significant difference in grit for medical students (M = 4.19, SD = 0.34) and residents (M =3.86, SD = 0.48); t(86) = 3.76, p = 0.000. All grit subscales were also significantly different for medical students versus residents. Medical students (conscientiousness M = 4.60, SD = 0.41; self-control M = 3.51, SD = 0.30) and residents (conscientiousness M = 4.42, SD = 0.53; self-control M = 3.31, SD = 0.73) scored similarly in the conscientiousness t(86) = 1.75, p = 0.084 and self-control scales t(86) = 1.74, p = 0.086. Academic performance indicators such as the USMLE scores and residency ranking were also compared among medical student applicants. CONCLUSIONS: The similar and above average levels of conscientiousness and self-control demonstrate the persevering nature of the individual who elects to pursue an orthopaedic residency program. Although the grit levels were different between medical school student and residents, they were above average for both groups, again demonstrating the type of individual willing to pursue an orthopaedic residency program. This study was the first to demonstrate varying degrees of grit for high-performing students versus residents in a competitive program, which seems to suggest that grit can vary over time. Future studies will investigate the validity of these non-cognitive variables in predicting achievement prospectively in a residency program