Comparing the mechanical properties, microstructure, texture and in-vitro degradation behavior of TNTZ/nano-fluorapatite composite and TNTZ bioalloy.

The present study deals with (i) the fabrication of the composite surface layer of Ti-29Nb-13Ta-4.6Zr/nano-fluorapatite through friction stir processing, (ii) clarifying the correlation of microstructure and texture with in-vitro degradation behavior and bioactivity of fabricated nano-biocomposite, and (iii) comparing the mechanical and functional properties of nano composite whit those obtained for TNTZ bio-alloy. The results indicated that increasing the number of deformation passes effectively refines the microstructure, leading to the average grain sizes of less than 5 µm. The texture of the material was also evolved in the presence of the nano particles where the grains reorient along <111> direction in contrast to the <101>-oriented grains in the starting microstructure. In-vitro bioactivity of the processed samples was measured after being immersed in simulated body fluid solution for various duration up to 30 days. Enhanced corrosion resistance and bio-mineralization of nanocomposite surface layer was discussed relying on the occurrence of grain refinement, substructure development and evolution of texture components along <101> direction. Assessment of the mechanical properties of the fabricated composites and as-received material also indicated the positive effect of the applied processing route and the presence of nano particles.

A cross sectional survey to estimate prevalence and associated factors of asthma on Reunion Island, Indian Ocean.

BACKGROUND: Previous studies on asthma mortality and hospitalizations in Reunion Island indicate that this French territory is particularly affected by this pathology. Epidemiological studies conducted in schools also show higher prevalence rates in Reunion than in Mainland France. However, no estimates are provided on the prevalence of asthma among adults. In 2016, a cross-sectional survey was conducted to estimate the prevalence of asthma and to identify its associated factors in the adult population of Reunion Island. METHODS: A random sample of 2419 individuals, aged 18-44 years, was interviewed by telephone using a standardized, nationally validated questionnaire. Information was collected on the respiratory symptoms, description of asthma attacks and triggering factors for declared asthmatics, as well as data on the indoor and outdoor home environment. "Current asthma" was defined as an individual declaring, at the time of the survey, having already suffered from asthma at some point during his/her life, whose asthma was confirmed by a doctor, and who had experienced an asthma attack in the last 12 months or had been treated for asthma in the last 12 months. "Current suspected asthma" was defined as an individual presenting, in the 12 months preceding the study, groups of symptoms suggestive of asthma consistent with the literature. RESULTS: The estimated prevalence of asthma was 5.4% [4.3-6.5]. After adjustment, women, obesity, a family member with asthma, tenure in current residence and presence of indoor home heating were associated with asthma. The prevalence of symptoms suggestive of asthma was 12.0% [10.2-13.8]. After adjustment, marital status, passive smoking, use of insecticide sprays, presence of mold in the home and external sources of atmospheric nuisance were associated with the prevalence of suspected asthma. CONCLUSION: Preventive actions including asthma diagnosis, promotion of individual measures to reduce risk exposure as well as the development of study to improve knowledge on indoor air allergens are recommended.

Reversion of a Parent {130}⟨310⟩_{α

In bcc metastable ß titanium alloys, and particularly in superelastic alloys, a unique {332}⟨113⟩ twinning system occurs during plastic deformation. However, in situ synchrotron x-ray diffraction during a tensile test shows that the ß phase totally transforms into α^{''} martensite under stress in a Ti-27Nb (at. %) alloy. {332}⟨113⟩_{ß} twins are thus not formed directly in the ß phase but are the result of the reversion of {130}⟨310⟩_{α^{''}} parent twins occurring in martensite under stress. The formation of an interfacial twin boundary ω phase is also observed to accommodate strains induced during the phase reversion.

[Security of the medicinal therapy: Cartography of risks a priori within service of orthopaedic surgery]. / Sécurisation de la prise en charge médicamenteuse : cartographie des risques a priori au sein du service de chirurgie orthopédique.

INTRODUCTION: Security and quality of the Medicinal Therapy are one of the most important objectives of the April 6th, 2011 order. The objective is to realize this study of the risks incurred by patients related to management and security of medicinal therapy in order to establish a plan to reduce the risks of drug's dispensation. MATERIALS AND METHOD: The method of the Preliminary Risk Analysis (PRA) has been implemented by a multidisciplinary group in a hospital service of orthopaedic surgery. The study focused on the dispensation phase of medicinal circuit. RESULTS: This analysis revealed 148 scenarii, 35 were criticality unacceptable. Fifty-four initial risk control actions were proposed and their stress levels to put them in place were evaluated. DISCUSSION: The main measures of risk management are: training, information, communication, computerization, automation, dual control, updating the documentation system, drug reconciliation and respect for Best Practices Hospitallers (BPH). CONCLUSIONS: Risk management requires a significant human and financial investment as well as, material resources and multidisciplinary expertise in order to offer the best solutions.

Wettability influence on the onset temperature of pool boiling: Experimental evidence onto ultra-smooth surfaces.

In this article we study systematically the effect of wettability on the onset of boiling on the same nanometrically smooth surface. By grafting different monolayers of molecules, we were able to explore the wettability from the equilibrium static contact angle, θ0=0° to θ0=110°, without changing the surface topography. The superheat temperature at the onset of pool boiling was measured and eventually a non-classical trend of TONB as a function of wettability was observed. The nucleation site densities for the different grafting cases were also measured by image analysis. Moreover, we propose a novel theoretical interpretation to this phenomenon linking nucleation and the molecular diffusion coefficient. MD simulation results support this approach.

Arginine: Its pKa value revisited.

Using complementary approaches of potentiometry and NMR spectroscopy, we have determined that the equilibrium acid dissociation constant (pKa value) of the arginine guanidinium group is 13.8 ± 0.1. This is substantially higher than that of ∼ 12 often used in structure-based electrostatics calculations and cited in biochemistry textbooks. The revised intrinsic pKa value helps explains why arginine side chains in proteins are always predominantly charged, even at pH values as great as 10. The high pKa value also reinforces the observation that arginine side chains are invariably protonated under physiological conditions of near neutral pH. This occurs even when the guanidinium moiety is buried in a hydrophobic micro-environment, such as that inside a protein or a lipid membrane, thought to be incompatible with the presence of a charged group.

[Delayed haemolytic transfusion reaction: About 3 patients with sickle cell disease]. / L'hémolyse post-transfusionnelle retardée : à propos de 3 patients drépanocytaires.

INTRODUCTION: The use of a red blood cell transfusion in a patient with major sickle cell disease is sometimes necessary. The occurrence of delayed haemolytic transfusion reaction is a rare but potentially serious complication. This event can occur at any age. It is probably under diagnosed due to the difficulty in diagnosis with few specific signs. CASE REPORTS: We describe in this article the clinical, biological, and hazards of therapeutic management of three cases of delayed haemolytic transfusion reaction in sickle cell disease patients. The high performance chromatography, which evaluates the percentage of HbA1, is the biological investigation used to establish the diagnosis of this event. The pathophysiology of this event remains still poorly understood. Several treatments have been used during this event. However, the therapeutic management remains controversial. CONCLUSION: Transfusion in any patient likely to suffer from delayed haemolytic transfusion reaction is not recommended because of the risk of worsening this reaction. Prevention of recurrence is essential.

In-plane mechanics of soft architectured fibre-reinforced silicone rubber membranes.

Silicone rubber membranes reinforced with architectured fibre networks were processed with a dedicated apparatus, allowing a control of the fibre content and orientation. The membranes were subjected to tensile loadings combined with continuous and discrete kinematical field measurements (DIC and particle tracking). These tests show that the mechanical behaviour of the membranes is hyperelastic at the first order. They highlight the influence of the fibre content and orientation on both the membrane in-plane deformation and stress levels. They also prove that for the considered fibrous architectures and mechanical loadings, the motion and deformation of fibres is an affine function of the macroscale transformation. These trends are fairly well described by the micromechanical model proposed recently in Bailly et al. (JMBBM, 2012). This result proves that these materials are very good candidates for new biomimetic membranes, e.g. to improve aortic analogues used for in vitro experiments, or existing textiles used for vascular (endo)prostheses.

RIP3 is downregulated in human myeloid leukemia cells and modulates apoptosis and caspase-mediated p65/RelA cleavage.

The receptor-interacting protein kinase 3 (RIP3) associates with RIP1 in a necrosome complex that can induce necroptosis, apoptosis, or cell proliferation. We analyzed the expression of RIP1 and RIP3 in CD34+ leukemia cells from a cohort of patients with acute myeloid leukemia (AML) and CD34+ cells from healthy donors. RIP3 expression was significantly reduced in most AML samples, whereas the expression of RIP1 did not differ significantly. When re-expressed in the mouse DA1-3b leukemia cell line, RIP3 induced apoptosis and necroptosis in the presence of caspase inhibitors. Transfection of RIP3 in the WEHI-3b leukemia cell line or in the mouse embryonic fibroblasts also resulted in increased cell death. Surprisingly, re-expression of a RIP3 mutant with an inactive kinase domain (RIP3-kinase dead (RIP3-KD)) induced significantly more and earlier apoptosis than wild-type RIP3 (RIP3-WT), indicating that the RIP3 kinase domain is an essential regulator of apoptosis/necroptosis in leukemia cells. The induced in vivo expression of RIP3-KD but not RIP3-WT prolonged the survival of mice injected with leukemia cells. The expression of RIP3-KD induced p65/RelA nuclear factor-κB (NF-κB) subunit caspase-dependent cleavage, and a non-cleavable p65/RelA D361E mutant rescued these cells from apoptosis. p65/RelA cleavage appears to be at least partially mediated by caspase-6. These data indicate that RIP3 silencing in leukemia cells results in suppression of the complex regulation of the apoptosis/necroptosis switch and NF-κB activity.

[Sociocultural and medical management of hypertension in sub-Saharan Africa]. / Prise en charge socioculturelle et médicale de l'hypertension artérielle en Afrique subsaharienne.

Hypertension has now become very prevalent in sub-Saharan Africa, in part due to the region's epidemiologic transition. Its long asymptomatic onset explains its late recognition and thus the high frequency of complications. Sociocultural conditions play an important role in the genesis of the disease in this region and in the difficulties encountered in its management. The breakdown of traditional ways of life, growing urbanization, and the switch to a western lifestyle and diet all have well-known deleterious effects on the cardiovascular system. High salt consumption, sedentarity, overweight and alcohol intake all promote these developments. The insufficient availability of medical care, poverty, and poor understanding of chronic diseases complicate the medical management of hypertension. In these regions, it is now a public health challenge that requires the training of healthcare workers and the involvement of the society as a whole, including political decisions, health education for school-children, and actions by social organizations and local officials and leaders. This communication must always respect traditional customs. Both curative measures and preventive actions are essential. Priority must be given to combatting excessive salt consumption, for the results of its reduction are known to be rapid and positive. Preventing or reducing overweight and obesity, sedentarity, and alcohol and tobacco consumption are effective steps against hypertension, but also atheromatous cardiovascular diseases and diabetes. Drug therapy must meet the three essential criteria: it must be effective, available, and inexpensive. Hypertension is not inevitable, but reflects changes in society. It appears to be transmitted in part by modern lifestyles, which can be modified.

[An a priori risk analysis study. Securisation of transfusion of blood product in a hospital: from the reception in the medical unit to its administration]. / Cartographie des risques a priori. Sécurisation de la transfusion d'un produit sanguin labile, dans un établissement de santé : de sa réception à son administration.

Following an ABO accident after transfusion of red blood cells, an a priori risk analysis study is being performed in a hospital. The scope of this analysis covers from the reception of the blood product in the medical unit to its administration. The risk analysis enables to identify the potentially dangerous situations and the evaluation of the risks in order to propose corrective measures (precautionary or protective) and bring the system back to an acceptable risk level. The innovative concept of an a priori risk analysis in the medical field allows the extension of the analysis of this transfusion risk to other hospitals. In addition, it allows the extension of the use of this approach to other medical fields.

Structural, energetic, and dynamic responses of the native state ensemble of staphylococcal nuclease to cavity-creating mutations.

The effects of cavity-creating mutations on the structural flexibility, local and global stability, and dynamics of the folded state of staphylococcal nuclease (SNase) were examined with NMR spectroscopy, MD simulations, H/D exchange, and pressure perturbation. Effects on global thermodynamic stability correlated well with the number of heavy atoms in the vicinity of the mutated residue. Variants with substitutions in the C-terminal domain and the interface between α and ß subdomains showed large amide chemical shift variations relative to the parent protein, moderate, widespread, and compensatory perturbations of the H/D protection factors and increased local dynamics on a nanosecond time scale. The pressure sensitivity of the folded states of these variants was similar to that of the parent protein. Such observations point to the capacity of the folded proteins to adjust to packing defects in these regions. In contrast, cavity creation in the ß-barrel subdomain led to minimal perturbation of the structure of the folded state, However, significant pressure dependence of the native state amide resonances, along with strong effects on native state H/D exchange are consistent with increased probability of population of excited state(s) for these variants. Such contrasted responses to the creation of cavities could not be anticipated from global thermodynamic stability or crystal structures; they depend on the local structural and energetic context of the substitutions.

Cavities determine the pressure unfolding of proteins.

It has been known for nearly 100 years that pressure unfolds proteins, yet the physical basis of this effect is not understood. Unfolding by pressure implies that the molar volume of the unfolded state of a protein is smaller than that of the folded state. This decrease in volume has been proposed to arise from differences between the density of bulk water and water associated with the protein, from pressure-dependent changes in the structure of bulk water, from the loss of internal cavities in the folded states of proteins, or from some combination of these three factors. Here, using 10 cavity-containing variants of staphylococcal nuclease, we demonstrate that pressure unfolds proteins primarily as a result of cavities that are present in the folded state and absent in the unfolded one. High-pressure NMR spectroscopy and simulations constrained by the NMR data were used to describe structural and energetic details of the folding landscape of staphylococcal nuclease that are usually inaccessible with existing experimental approaches using harsher denaturants. Besides solving a 100-year-old conundrum concerning the detailed structural origins of pressure unfolding of proteins, these studies illustrate the promise of pressure perturbation as a unique tool for examining the roles of packing, conformational fluctuations, and water penetration as determinants of solution properties of proteins, and for detecting folding intermediates and other structural details of protein-folding landscapes that are invisible to standard experimental approaches.