Magnetic properties of small Pt-capped Fe, Co and Ni clusters: A density functional theory study

Theoretical studies on M$_{13}$ (M = Fe, Co, Ni) and M$_{13}$Pt$_n$ (for $n$ = 3, 4, 5, 20) clusters including the spin-orbit coupling are done using density functional theory. The magnetic anisotropy energy (MAE) along with the spin and orbital moments are calculated for M$_{13}$ icosahedral clusters. The angle-dependent energy differences are modelled using an extended classical Heisenberg model with local anisotropies. From our studies, the MAE for Jahn-Teller distorted Fe$_{13}$, Mackay distorted Fe$_{13}$ and nearly undistorted Co$_{13}$ clusters are found to be 322, 60 and 5 $\mu$eV/atom, respectively, and are large relative to the corresponding bulk values, (which are 1.4 and 1.3 $\mu$eV/atom for bcc Fe and fcc Co, respectively.) However, for Ni$_{13}$ (which practically does not show relaxation tendencies), the calculated value of MAE is found to be 0.64 $\mu$eV/atom, which is approximately four times smaller compared to the bulk fcc Ni (2.7 $\mu$eV/atom). In addition, MAE of the capped cluster (Fe$_{13}$Pt$_4$) is enhanced compared to the uncapped Jahn-Teller distorted Fe$_{13}$ cluster

Quantitative Genomics of Aggressive Behavior in Drosophila melanogaster

Aggressive behavior is important for animal survival and reproduction, and excessive aggression is an enormous social and economic burden for human society. Although the role of biogenic amines in modulating aggressive behavior is well characterized, other genetic mechanisms affecting this complex behavior remain elusive. Here, we developed an assay to rapidly quantify aggressive behavior in Drosophila melanogaster, and generated replicate selection lines with divergent levels of aggression. The realized heritability of aggressive behavior was approximately 0.10, and the phenotypic response to selection specifically affected aggression. We used whole-genome expression analysis to identify 1,539 probe sets with different expression levels between the selection lines when pooled across replicates, at a false discovery rate of 0.001. We quantified the aggressive behavior of 19 mutations in candidate genes that were generated in a common co-isogenic background, and identified 15 novel genes affecting aggressive behavior. Expression profiling of genetically divergent lines is an effective strategy for identifying genes affecting complex traits

Minimal-invasive anterior approach to the hip provides a better surgery-related and early postoperative functional outcome than conventional lateral approach after hip hemiarthroplasty following femoral neck fractures

Introduction Femoral neck fractures (FNF) are one of the most frequent fractures among elderly patients and commonly require surgical treatment. Bipolar hip hemiarthroplasty (BHHA) is mostly performed in these cases. Material and methods In the present retrospective study geriatric patients with FNF (n=100) treated either by anterior minimal-invasive surgery (AMIS; n=50) or lateral conventional surgery (LCS; n=50) were characterized (age at the time of surgery, sex, health status/ASA score, walking distance and need for walking aids before the injury) and intraoperative parameters (duration of surgery, blood loss, complications), as well as postoperative functional performance early (duration of in-patient stay, radiological leg length discrepancy, ability to full weight-bearing, mobilization with walking aids) and 12 months (radiological signs of sintering, clinical parameters, complication rate) after surgery were analyzed. Results Patients in the AMIS group demonstrated a reduced blood loss intraoperatively, while the duration of surgery and complication rates did not difer between the two groups. Further, more patients in the AMIS group achieved full weightbearing of the injured leg and were able to walk with a rollator or less support during their in-patient stay. Of interest, patients in the AMIS group achieved this level of mobility earlier than those of the LCS group, although their walking distance before the acute injury was reduced. Moreover, patients of the AMIS group showed equal leg lengths postoperatively more often than patients of the LCS group. No signifcant diferences in functional and surgery-related performance could be observed between AMIS and LCS group at 12 months postoperatively. Conclusions In conclusion, geriatric patients treated by AMIS experience less surgery-related strain and recover faster in the early postoperative phase compared to LCS after displaced FNF. Hence, AMIS should be recommended for BHHA in these vulnerable patients

The accuracy of respiratory rate assessment by doctors in a London teaching hospital: a cross-sectional study

Respiratory rate (RR) is one of the most sensitive markers of a patient condition and a core aspect of multiple clinical assessment tools. Doctors use a number of methods to assess RR, including formal measurement, and 'spot' assessments, although this is not recommended. This study aimed to assess the accuracy of the methods of RR measurement being used by doctors. A cross-sectional study assessing the accuracy (range, bias, and imprecision) of doctors' 'spot' and 'formal' respiratory rate assessments, using videos of mock patients. 54 doctors in a London teaching hospital participated. Both methods showed high levels of inaccuracy, though formal methods were more accurate than 'spot' assessments. 52 and 19 % of doctors did not identify the respiratory rates shown as abnormal, using 'spot' and formal assessment methods respectively. We observed a trend towards decreasing accuracy of 'spot' assessments with increasing clinical experience (p = 0.0490). Current methods of RR assessment by doctors are inaccurate. This may be significantly delaying appropriate clinical care, or even misguiding treatment

Pantoprazole impairs fracture healing in aged mice

Proton pump inhibitors (PPIs) belong to the most common medication in geriatric medicine. They are known to reduce osteoclast activity and to delay fracture healing in young adult mice. Because differentiation and proliferation in fracture healing as well as pharmacologic actions of drugs markedly differ in the elderly compared to the young, we herein studied the effect of the PPI pantoprazole on bone healing in aged mice using a murine fracture model. Bone healing was analyzed by biomechanical, histomorphometric, radiological and protein biochemical analyses. The biomechanical analysis revealed a significantly reduced bending stiffness in pantoprazole-treated animals when compared to controls. This was associated with a decreased amount of bone tissue within the callus, a reduced trabecular thickness and a higher amount of fibrous tissue. Furthermore, the number of osteoclasts in pantoprazole-treated animals was significantly increased at 2 weeks and decreased at 5 weeks after fracture, indicating an acceleration of bone turnover. Western blot analysis showed a lower expression of the bone morphogenetic protein-4 (BMP-4), whereas the expression of the pro-angiogenic parameters was higher when compared to controls. Thus, pantoprazole impairs fracture healing in aged mice by affecting angiogenic and osteogenic growth factor expression, osteoclast activity and bone formation

Profiling microRNA expression in murine bone healing and non-union formation: Role of miR-140 during the early stage of bone healing

Although cellular and molecular mechanisms during the course of bone healing have been thoroughly investigated, the regulation of gene expression by microRNA during bone regen eration is still poorly understood. We hypothesized that nonunion formation is associated with different microRNA expression patterns and that target proteins of these microRNAs are differently expressed in callus tissue of nonunions compared to physiologically healing bones. In a well-established femoral osteotomy model in CD-1 mice osteotomies were induced which result either in healing or in nonunion formation. MicroRNA and target protein expression was evaluated by microarray, quantitative real-time polymerase chain reaction (qrt-PCR) and Western blot. Microarray analyses demonstrated 44 microRNAs to be rele vant for nonunion formation compared to physiological bone healing. In nonunions qrt-PCR could validate a higher expression of microRNA-140-3p and microRNA-140-5p. This was associated with a reduced expression of Dnpep and stromal cell-derived factor (SDF)-1α, which are both known to be target proteins of microRNA-140 and also to be involved in the process of bone healing. These data suggest that an increased expression of microRNA 140-3p and microRNA-140-5p markedly contributes to the development of nonunions, most probably by affecting bone morphogenetic protein (BMP)-2 function during the early stage of healing due to a reduced SDF-1α expression

Diclofenac, a NSAID, delays fracture healing in aged mice

Nonsteroidal anti-inflammatory drugs (NSAIDs), such as diclofenac, belong to the most prescribed analgesic medication after traumatic injuries. However, there is accumulating evidence that NSAIDs impair fracture healing. Because bone regeneration in aged patients is subject to significant changes in cell differentiation and proliferation as well as a markedly altered pharmacological action of drugs, we herein analyzed the effects of diclofenac on bone healing in aged mice using a stable closed femoral facture model. Thirty-three mice (male n = 14, female n = 19) received a daily intraperitoneal injection of diclofenac (5 mg/kg body weight). Vehicletreated mice (n = 29; male n = 13, female n = 16) served as controls. Fractured mice femora were analyzed by means of X-ray, biomechanics, micro computed tomography (μCT), histology and Western blotting. Biomechanical analyses revealed a significantly reduced bending stiffness in diclofenac-treated animals at 5 weeks after fracture when compared to vehicle-treated controls. Moreover, the callus tissue in diclofenac-treated aged animals exhibited a significantly reduced amount of bone tissue and higher amounts of fibrous tissue. Further histological analyses demonstrated less lamellar bone after diclofenac treatment, indicating a delay in callus remodeling. This was associated with a decreased number of osteoclasts and an increased expression of osteoprotegerin (OPG) during the early phase of fracture healing. These findings indicate that diclofenac delays fracture healing in aged mice by affecting osteogenic growth factor expression and bone formation as well as osteoclast activity and callus remodeling

Mate discrimination among subspecies through a conserved olfactory pathway.

Communication mechanisms underlying the sexual isolation of species are poorly understood. Using four subspecies of Drosophila mojavensis as a model, we identify two behaviorally active, male-specific pheromones. One functions as a conserved male antiaphrodisiac in all subspecies and acts via gustation. The second induces female receptivity via olfaction exclusively in the two subspecies that produce it. Genetic analysis of the cognate receptor for the olfactory pheromone indicates an important role for this sensory pathway in promoting sexual isolation of subspecies, in combination with auditory signals. Unexpectedly, the peripheral sensory pathway detecting this pheromone is conserved molecularly, physiologically, and anatomically across subspecies. These observations imply that subspecies-specific behaviors arise from differential interpretation of the same peripheral cue, reminiscent of sexually conserved detection but dimorphic interpretation of male pheromones in Drosophila melanogaster. Our results reveal that, during incipient speciation, pheromone production, detection, and interpretation do not necessarily evolve in a coordinated manner