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For a sample of 38 galactic globular clusters (GCs), we confront the observed distributions of blue straggler (BS) proper motions and masses (derived from isochrone fitting) from the BS catalogue of Simunovic & Puzia with theoretical predictions for each of the two main competing BS formation mechanisms. These are mass transfer from an evolved donor on to a main-sequence (MS) star in a close binary system, and direct collisions involving MS stars during binary encounters. We use the FEWBODY code to perform simulations of single–binary and binary–binary interactions. This provides collisional velocity and mass distributions for comparison to the observed distributions. Most clusters are consistent with BSs derived from a dynamically relaxed population, supportive of the binary mass-transfer scenario. In a few clusters, including all the post-core collapse clusters in our sample, the collisional velocities provide the best fit. [ABSTRACT FROM AUTHOR]

Studies of limb bone loading in terrestrial mammals have typically found anteroposterior bending to be the primary loading regime, with torsion contributing minimally. However, previous studies have focused on large, cursorial eutherian species in which the limbs are held essentially upright. Recent in vivo strain data from the Virginia opossum (Dideiphis virginiana), a marsupial that uses a crouched rather than an upright limb posture, have indicated that its femur experiences appreciable torsion during locomotion as well as strong mediolateral bending. The elevated femoral torsion and strong mediolateral bending observed in D. virginiana might result from external forces such as a medial inclination of the ground reaction force (GRF), internal forces deriving from a crouched limb posture, or a combination of these factors. To evaluate the mechanism underlying the loading regime of opossum femora, we filmed D. virginiana running over a force platform, allowing us to measure the magnitude of the GRF and its three-dimensional orientation relative to the limb, facilitating estimates of limb bone stresses. This three-dimensional analysis also allows evaluations of muscular forces, particularly those of hip adductor muscles, in the appropriate anatomical plane to a greater degree than previous two-dimensional analyses. At peak GRF and stress magnitudes, the GRF is oriented nearly vertically, inducing a strong abductor moment at the hip that is countered by adductor muscles on the medial aspect of the femur that place this surface in compression and induce mediolateral bending, corroborating and explaining loading patterns that were identified in strain analyses. The crouched orientation of the femur during stance in opossums also contributes to levels of femoral torsion as high as those seen in many reptilian taxa. Femoral safety factors were as high as those of non-avian reptiles and greater than those of upright, cursorial mammals, primarily because the load magnitudes experienced by opossums are lower than those of most mammals. Thus, the evolutionary transition from crouched to upright posture in mammalian ancestors may have been accompanied by an increase in limb bone load magnitudes. [ABSTRACT FROM AUTHOR]

Localized delivery of small interfering RNA (siRNA) is a promising approach for spatial control of cell responses at biomaterial interfaces. Layer-by-layer (LbL) assembly of siRNA with cationic polyelectrolytes has been used in film and nanoparticle vectors for transfection. Herein, we combine the ability of particles to efficiently deliver siRNA with the ability of film polyelectrolyte multilayers to act locally. LbL particles were prepared with alternating layers of poly(l-arginine) and siRNA and capped with hyaluronic acid. Negatively charged LbL particles were subsequently assembled on the poly(l-lysine)-functionalized substrate to form a LbL particle-decorated surface. Cells grown in contact with the particle-decorated surface were able to survive, internalize particles, and undergo gene silencing. This work shows that particle-decorated surfaces can be engineered by using electrostatic interactions and used to deliver therapeutic payloads for cell-instructive biointerfaces.

As the overall U.S. population grows older and increasingly diverse, greater focus is needed on the various Home and Community-Based Services (HCBS), such as home health care, case management, meal delivery and preparation, and personal care, required to address the unique social and medical complexities of diverse older adults. Presently, however, there has been limited research on needs and broader dynamics associated with HCBS facilitation in this population. To address this gap, we sought to contextualize practices and barriers to care coordination for diverse homebound older adults, conducting semi-structured interviews with 41 providers of HCBS, including older adult care coordinators, in-home care workers, and physicians in greater Chicago, Illinois. Common care coordination practices included fluid processes related to engendering racial concordance in care, facilitating linguistic adaptations, and navigating relationships with clients' families. However, in certain circumstances, these practices are hindered. For example, broad client-level challenges included racialized dynamics of distrust and limited health literacy, and organizations cited ongoing obstacles recruiting and retaining diverse staff and finding HCBS providers to service low-income, minority communities often burdened by high crime rates. Continued efforts need to be made to better understand the HCBS needs of diverse homebound older adults and the associated challenges of providing culturally humble programming to this population., (Copyright © 2022 Elsevier Inc. All rights reserved.)

In a study of multicase RA families, significantly raised frequencies of the HLA antigens DR4, DR1, Bw62, Cw3, A2, A31 and significantly lower frequencies of DR2, DR3, and B8 were found in probands compared to normal controls. When haplotype frequencies were compared between probands and controls, two haplotypes A2-B44-DR4 and A2-Bw62-DR4 were at higher frequency in probands. These differences no longer reached significance when only DR4-containing haplotypes were compared between probands and controls. A significantly lower haplotype frequency of A1-B8-DR3 was observed in probands compared to controls. This difference did not remain significant when only non-DR4 haplotypes were compared. Using an affected sibling pair ratio method, significant linkage between HLA and RA was found (P less than 0.01). Significant linkage was also observed between HLA and seropositivity. Analysis of Hardy-Weinberg equilibrium for the DR locus did not support the suggestion that DR4-associated RA susceptibility was inherited as a dominant trait. In addition it did not support the notion of an additive effect of DR4 and DR1 in RA susceptibility as these antigens were not found together more frequently than predicted by their individual gene frequencies.