Ageing of out-of-equilibrium nanoalloys by a kinetic mean-field approach.

This study describes the ageing of bimetallic nanoparticles using a kinetic mean-field method which provides the time evolution of the concentration for each site. We consider the cuboctahedron of 309 atoms in the Cu-Ag system, which is a prototype of systems with a strong tendency to phase separate. Starting from an initial homogenous configuration, we investigate the evolution towards the equilibrium configuration at different temperatures. Surprisingly, at low temperature, the kinetics exhibits a first transition towards an onion-like configuration followed by a second transition towards the equilibrium core-shell configuration. An analysis of the kinetics of the formation and then of the dissolution of the onion-like structure allows us to identify the main paths of the kinetic process.

Phase diagrams of nanoalloys: influence of size and morphology.

The size dependence of the phase diagram of nanoalloys with a tendency to phase separate is investigated. As the critical temperature may depend on both the size and the morphology of the nanoparticles, we consider nanowires with different cross-sections and also nanotubes with different circumferences. The variation of the critical temperature with the length of all these nanoparticles is systematically studied using Monte Carlo simulations based on an Ising model. A non-monotonic variation of the critical temperature is observed as a function of the length. The maximal value of the critical temperature is reached when the length and the circumference of the nanoparticles are similar. The phase diagrams obtained within two thermodynamic ensembles (the canonical ensemble and the pseudo grand canonical ensemble) are compared and discussed in terms of the behaviour of a single particle or an assembly of nanoparticles in mutual equilibrium with each other.

Penetration of daptomycin into bone and synovial fluid in joint replacement.

Daptomycin exhibits clinical activity in the treatment of infections with Gram-positive organisms, including infections due to methicillin-resistant Staphylococcus aureus. However, little is known about its penetration into bone and synovial fluid. The aim of our study was to assess the penetration of daptomycin into bone and synovial fluid after a single intravenous administration. This study was conducted in 16 patients who underwent knee or hip replacement and received a single intravenous dose of 8 mg of daptomycin per kg of body weight prior to surgery. Plasma daptomycin concentrations were measured 1 h after the end of daptomycin infusion and when bone fragments were removed. Daptomycin concentrations were also measured on bone fragments and synovial fluid collected at the same time during surgery. All samples were analyzed with a diode array-high-performance liquid chromatography (HPLC) method. After a single-dose intravenous infusion, bone daptomycin concentrations were above the MIC of daptomycin for Staphylococcus aureus in all subjects, and the median bone penetration percentage was 9.0% (interquartile range [IQR], 4.4 to 11.4). These results support the use of daptomycin in the treatment of Staphylococcus aureus bone and joint infections.

Hand and wrist Osteo-articular bone defect: induced membrane technique indications.

Bone defect in the hand and wrist is the result of 3 main causes: traumatic, infectious or tumoral. Whatever the cause and possibility of emergency management, the site (hand or wrist) and anatomical location (articular or diaphyseal) guide the choice of surgical technique and timing. Functional sequelae do not vary, and the ultimate objective is not so much to fill a defect but to give a useful and accepted finger, hand or wrist.

Extending cluster description to bimetallic nanowires: the ideal solid solution alloy case.

We present a comprehensive study of the equilibrium properties of two codeposited species for an alloy that forms an ideal solution, on a one-dimensional chain. By use of a cluster description we provide exact formulae of the coverages, the total density of clusters, the cluster size distribution, and the chemical composition of each cluster. These analytical results, that are proved to be in agreement with Monte Carlo simulations, strongly differ from the ones derived in the mean-field framework. Indeed, we show by depicting the codeposit at the macroscopic, mesoscopic, and atomic scales, that its features are to be related to the chemical heterogeneities at the edges of the clusters.

[Impact of AMARA VIEW™ interface on upper airway during nocturnal non invasive ventilation]. / Impact de l'interface AMARA VIEW™ sur les voies aériennes supérieures au cours de la ventilation non invasive nocturne.

INTRODUCTION: Nasal masks can result in mouth leaks with implications on sleep quality. To reduce these leaks, oronasal masks are proposed. It has been shown that an oronasal mask can induce obstructive events in the upper airways (UA). Because of its fit around the nose, the Amara View™ facial mask may have less consequence on UA obstruction. METHODS: This retrospective study assessed the impact of the Amara View™ mask on UA. The study was conducted on patients with chronic respiratory failure treated by home NIV with standard facial mask. Replacement of the standard facial mask by an Amara View™ mask was performed when the residual apnea hypopnea index recorded from the ventilator software exceeded 5/h. All patients underwent nocturnal respiratory polygraphy when on NIV with a standard facial mask and with an Amara View™ mask. Respiratory polygraphic traces were interpreted following the analysis methods published by the SomnoNIV Group. RESULTS: Seven patients were studied. Although nocturnal oxygen saturation was similar between both masks, the index of UA obstruction without ventilatory blunting was significantly lower during NIV with the Amara View™ mask compared to the standard facial mask (P=0.01). CONCLUSIONS: Nocturnal NIV using an Amara View™ facial interface may avoid UA obstruction without ventilatory command blunting.

Analysis of Au-Pd driving forces via the effective site energy model: LRO, antisites and enthalpy of permutation.

Recently we have developed a new energetic model based on the determination of the energies on each site of random solid solutions after relaxation as a function of both the local composition and the nominal concentration. It allows to determine the main thermodynamics driving forces of disordered alloys. Here, we extend the effective site energy model to ordered alloys and illustrate the results for the Au c Pd1-c system. As a first step, we show the ability of this energetic model to reproduce the hierarchy of ordered phases. Then, we derive general mean-field analytic formulae for ordered systems and get the phase diagram. We determine the relative role of the cohesive effect, the chemical effect and the size effect and find that the chemical effect differs significantly between the disordered state and the ordered state. Finally, we link the energy formation of antisite to the permutation enthalpy and give the driving forces for the formation of antisite.

Impact of two-level filtering on emergency medical communication center triage during the COVID-19 pandemic: an uncontrolled before-after study.

BACKGROUND: Rapid access to emergency medical communication centers (EMCCs) is pivotal to address potentially life-threatening conditions. Maintaining public access to EMCCs without delay is crucial in case of disease outbreak despite the significant increased activity and the difficulties to mobilize extra staff resources. The aim of our study was to assess the impact of two-level filtering on EMCC performance during the COVID-19 outbreak. METHODS: A before-after monocentric prospective study was conducted at the EMCC at the Nantes University Hospital. Using telephone activity data, we compared EMCC performance during 2 periods. In period one (February 27th to March 11th 2020), call takers managed calls as usual, gathering basic information from the caller and giving first aid instructions to a bystander on scene if needed. During period two (March 12th to March 25th 2020), calls were answered by a first-line call taker to identify potentially serious conditions that required immediate dispatch. When a serious condition was excluded, the call was immediately transferred to a second-line call taker who managed the call as usual so the first-line call taker could be rapidly available for other incoming calls. The primary outcome was the quality of service at 20 s (QS20), corresponding to the rate of calls answered within 20 s. We described activity and outcome measures by hourly range. We compared EMCC performance during periods one and two using an interrupted time series analysis. RESULTS: We analyzed 45,451 incoming calls during the two study periods: 21,435 during period 1 and 24,016 during period 2. Between the two study periods, we observed a significant increase in the number of incoming calls per hour, the number of connected call takers and average call duration. A linear regression model, adjusted for these confounding variables, showed a significant increase in the QS20 slope (from - 0.4 to 1.4%, p = 0.01), highlighting the significant impact of two-level filtering on the quality of service. CONCLUSIONS: We found that rapid access to our EMCC was maintained during the COVID-19 pandemic via two-level filtering. This system helped reduce the time gap between call placement and first-line call-taker evaluation of a potentially life-threatening situation. We suggest implementing this system when an EMCC faces significantly increased activity with limited staff resources.

Assessment of topographic brachial plexus nerves variations at the axilla using ultrasonography.

BACKGROUND: The aim of this study was to describe topographic variations in the arrangement of the four main brachial plexus nerves at the junction of the axilla and the upper part of the arm. METHODS: In 153 patients undergoing upper arm surgery using axillary block, we studied nerve arrangements with a three-step approach, combining: (A) cross-sectional ultrasound imaging using a 12 MHz linear ultrasound probe; (B) distal shift of the ultrasound scanhead from the axilla to the elbow joint following the paths of individual nerves; and (C) identifying the distal motor response to electrical nerve stimulation of each nerve. These results were then converted into a 12-section pie chart with the axillary artery (AA) as the axis. RESULTS: The order of the nerves around the AA was median, ulnar, radial, and musculocutaneous in all cases. The most frequent arrangement was observed in 65% of the patients. Five less frequent variations were observed in 4-20% of the patients, with four other variations seen in <2% of the patients. In 78% of the cases, the four nerves were seen separately using static ultrasound imaging. The musculocutaneous nerve was close to the artery in 18% of the patients. CONCLUSIONS: Topographic variations of the four main nerves at the axilla were found to be numerous, the most frequent arrangement being seen in less than two-thirds of the patients. Four separate nerves were seen on static ultrasound imaging at this sectional level of the axilla in only 78% of the cases.

Bridging the gap between adult and paediatric outcomes in HIV-1 vertically infected children: a single-centre comparison with adult data.

UNLABELLED: Prognosis of HIV-1 infection dramatically improved during the last decade. Meanwhile, treatment-induced virological success has always been different in adult and children patients. AIM: To compare 10 years of follow up in HIV-1 vertically infected children and adult patients. METHODS: Monocentric retrospective longitudinal analysis of vertically HIV-1-infected children and adult patients followed in the Nice University Hospital between 1999 and 2008. Immunological, virological and antiretroviral treatment data were recorded. RESULTS: Forty children and 1752 adult patients were included. Between 1996 and 2008, the percentage of children receiving HAART increased from 3.2% to 91%. Mean CD4% in the paediatric group remained stable between 29 +/- 8.1% in 1998 and 30 +/- 9.4% in 2008. Mean adult CD4-cell count significantly increased from 410 in 1998 to 556 cells/mL in 2008. Logistic regression analysis showed that the children-to-adult difference for indetectability (HIV PCR-RNA below 400 copies/mL) was significant (p < 0.0001) with an odds ratio of 0.61 (CI(95th): 0.52-0.72). Year-to-patient interaction was also significant with a decreasing divergence over time (p: 0.038). CONCLUSION: Nowadays as in adult patients, the control of HIV-1 replication is achieved in nearly eight of 10 children and the percentage of patients with severe immunodeficiency dramatically decreased compared with the mid 1990s.

[Who are the recipients of labile blood products? A multicenter nation-wide study--a "donation day." Blood banks, health facilities]. / Qui sont les receveurs de produits sanguins labiles (PSL)? Une étude nationale multicentrique - un jour donné. Etablissement de transfusion sanguine (ETS) - établissements de santé (ES).

During the years 1994-2001, a progressive decrease of the number of blood units transfused has been reported in France. In contrast, since 2002, there is an increasing number of blood units issuing (+7.6% between 2001 and 2006) and this must be investigated. On behalf of the French Society of Blood Transfusion, the "Recipients" working group promoted a nation wide survey with the support of the regional blood transfusion centres. This survey was aimed at describing the profiles of the transfused patients: socio-demographical patterns, and reasons of the blood transfusion (main and associated diagnoses). A cross-sectional survey was designed. All the patients who received a blood unit during a specific day were considered as the population of the study. They were identified by the regional transfusion centres by means of the "individual issuing form". Survey forms were fully filled for 90% of the patients. It has been considered as a good answer rate. Seven thousand four hundred and twenty-two blood units, delivered to 3450 patients were analyzed. Three groups of pathologies were found as a reason of transfusion: haematology-oncology (52.70% of the prescriptions) with 892 patients (27.8%) for haematological malignancies; surgical procedures (23.99%); intensive care and medicine procedures (21.92%). More than 50% of the recipients are 70 years old and more. This result is explained by the age distribution of inpatients. In a context of lack of donors and consequently difficulties to provide patients with optimal number of blood units, this study is helpful. Variability of blood unit issuings must be detected, analyzed and monitored in real time by the actors of the transfusion process, using computerized dashboards: the blood units provider (in order to adjust the strategy of blood units provision) and the health care establishment as well as care blood components prescribers (reasons of blood transfusion and evaluation of practices).

[Intravenous thrombolysis with rt-PA in stroke: experience of the Nice stroke unit]. / Thrombolyse intraveineuse par rt-PA des accidents vasculaires cérébraux ischémiques : l'expérience de l'unité neurovasculaire de Nice.

INTRODUCTION: Intravenous thrombolysis with rt-Pa in stroke has been approved in France since 2002. We report an evaluation of our practice. We have tried to identify predictive factors of dependence and death, and to compare our results with the data of the literature. PATIENTS AND METHOD: All patients treated with intravenous rt-PA within the first 270min after the stroke onset were included. Univariate, then multivariate analyses were performed to determine the variables influencing the functional outcome at 3 months follow-up, according to a dichotomy established from the modified Rankin scale. RESULTS: One hundred and forty-two patients were included in this study (mean initial National Institute of Health Stroke Scale [NIHSS]: 15). Fifty percent had a Rankin score higher than 2 at 3 months follow-up. NIHSS above 12, glycemia of at least 120mg/l, and systolic blood pressure above 160mmHg at admission were identified as independent predictive factors of poor functional outcome. Less than 4 points decrease of NIHSS proved to be a simple and early predictor of poor functional outcome at 3 months follow-up. CONCLUSIONS: In terms of safety and efficacy the data issuing from the daily activity of our stroke unit are comparable with those of clinical trials.

[Anatomy of the female pelvis on MRI: value of intravaginal contrast]. / Anatomie pelvienne en IRM: apport du contraste vaginal.

PURPOSE: Prospective monocentric study to determine the feasibility, tolerability and diagnostic value of intravaginal contrast to assess female pelvic anatomy on MRI. MATERIALS AND METHODS: Forty-nine consecutive women referred for MRI evaluation of the pelvis, irrespective of the indication, were included in this study. The MR imaging protocol consisted of axial and sagittal T2W images before and after intravaginal instillation of sterile US gel. Eight anatomical regions were analyzed and their visibility graded from 1 to 4 (1=excellent; 4=non-visualized) by 3 radiologists without and with intravaginal gel. The value of intravaginal gel was determined by calculating the difference in the visibility index for each anatomical region by the Wilcoxon and khi2 tests. Inter-observer agreement was also determined using the kappa test. RESULTS: Two women declined vaginal opacification resulting in an acceptance rate of 96%. The gel instillation procedure had a duration of less than 3 minutes on average and was well tolerated by all patients. Intravaginal gel allowed significantly improved visualization of all anatomical regions (p<0.001); improvement between 0.5 and 2.5 points on average per anatomical region. Inter-observer agreement significantly improved after gel instillation increasing from 72% to 92%. CONCLUSION: Intravaginal instillation of US gel is simple, noninvasive, well-accepted and well-tolerated by patients. It increases visibility of pelvic anatomical structures with improved inter-observer agreement.

[Phenotypical aspects and clinical course of multiple sclerosis in 76 patients with a North African ethnic background followed at the Nice University Hospital]. / Caractéristiques phénotypiques et évolutives de la SEP chez des patients originaires du Maghreb et suivis au CHRU de Nice (à propos d'une cohorte de 76 patients).

AIMS: In the European multiple sclerosis (MS) database registered in Nice, about 8p.cent of the patients have a North African ethnic background. PATIENTS AND METHODS: We performed a descriptive retrospective study of a cohort of 76 MS patients with a North African ethnic background followed in the Neurology Department of Nice University Hospital. This group was compared with a regional MS cohort (n=968) from our EDMUS database. Statistical analysis enabled classification of patients into three subgroups which had been submitted to different environmental factors according to where they were born and their age at immigration. There were prognostic aspects specific to each group. RESULTS: Regarding the entire cohort, poor prognostic factors included male gender, onset with sequellae, and substantial brain lesions on initial T2-weighted MRI. For the subgroups, prognostic aspects specific to each group were: 1) patients of North African origin born in France had an early age of onset, delayed diagnosis, remission between two long initial expressions of MS, and rapidly developed cerebellar problems with a secondary progressive course: 2) patients having migrated after age 15 had a late age of onset, delayed diagnosis, remission between two short initial expressions of MS, an onset characterized by one symptom, which was often a motor symptom involving the spinal cord or brain stem, but late-developing cerebellar problems and secondary progressive course are frequent; 3) patients having migrated before age 15 had an onset characterized by one symptom, often a visual problem, with sequellae and rapid development of cerebellar problems. CONCLUSION: The present study was consistent with the more unfavorable course of MS in patients of North African ethnic background previously reported in the literature. One should distinguish the subgroups to improve management of MS. Early administration of treatment should be considered for these patients, including earlier and more frequent use of immunosuppressive agents.

[CARIMS (Cancer Risk In Multiple Sclerosis) project: impact of long-term treatment]. / Cancer et sclérose en plaques. Impact des traitements de fonds et présentation du projet CARIMS (Cancer Risk In Multiple Sclerosis).

Controversial results have been published on potential link between cancer and multiple sclerosis. Multiple sclerosis has been linked to reduced rates of cancer prior to the era of immunomodulating or immunosuppressive treatments and until today, only 9 studies can be found in the literature. New strategies and early use of IM or IS drugs in MS justify to study and follow patients to detect a potential increase of cancer's incidence in treated patients. It is important to follow and collect prospectively in MS centers, patients with history of cancer, to document histologies, and potential relations with repeated IM or IS treatments. A prospective study is in progress in French MS centers on behalf the Club Francophone de la SEP (CARIMS Project).

[Life-threatening postpartum hemorrhage and recombinant activated factor rFVIIa NovoSeven use]. / Hémorragie de la délivrance "menaçant la vie" et utilisation du facteur VII recombinant activé rFVIIa NovoSeven.

Postpartum haemorrhage remains a dangerous obstetrical complication, which is the main cause of maternal mortality in developing countries. The diagnosis must be immediate and its management is both medically and surgically in life-threatening haemorrhage. We present a case of a thirty-three-year-old woman who asked a pregnancy interruption for premature rupture of membranes at 21(th) gestational week for her second pregnancy; she underwent a caesarean section at term for her first pregnancy. She delivered vaginally and developed a postpartum haemorrhage with hemorrhagic shock which was resistant to medical, surgical and radiological management. We decided to use recombinant activated factor VII (rFVIIa, NovoSeven) as a final attempt to rescue the patient. During surgery, two intravenous bolus injections (60, 120 mug/kg) were successfully given with a control of bleeding and haemoglobin. The patient developed later a splenic thrombosis that can be related to either rFVIIa or to the hypovolemic shock or to the sepsis. Recombinant activated factor VII is an interesting and promising haemostatic agent in the management of life-threatening postpartum haemorrhage unresponsive to conventional treatment.

[Effectiveness of adjuvant corticosteroid therapy for chronic subdural hematoma: a retrospective study of 198 cases]. / Efficacité de la corticothérapie dans le traitement adjuvant des hématomes sous-duraux chroniques. Etude rétrospective sur 198 cas.

BACKGROUND AND PURPOSE: Adjuvant treatments can be proposed in addition to surgery for patients with chronic subdural hematoma (CSDH) in order to improve the postoperative outcome. According to the survey published in 2001 by the Neurosurgery French Society, 38% of French neurosurgeons use adjuvant corticosteroid therapy after surgery. Does this adjuvant corticosteroid therapy have an effect on the postoperative outcome of CSDH? METHODS: A retrospective trial was performed on patients who were surgically treated for CSDH between January 1998 and July 2002 in the Nice Department of Neurosurgery. Corticosteroid therapy was initiated just after surgery and maintained for one month. Part of the patients were not given corticosteroids enabling a comparison of two groups: "corticosteroid therapy" versus "no corticosteroid therapy". RESULTS: One hundred and ninety-eight patients were included in the trial, 142 patients in the "corticosteroid therapy" group and 56 patients in the "no corticosteroid therapy" group. The difference in survival between the two groups was significant in favor of the group give corticosteroids. A multivariate analysis was carried out which confirmed the beneficial effect of the corticosteroid therapy on survival of the operated patients. Their risk of death was threefold less than those not given this treatment (p=0.006). CONCLUSIONS: This study highlighted a protective effect of postoperative corticosteroid therapy on patient survival. This effect persisted at multivariate analysis. However, due to skews inherent in retrospective studies, a multicentric prospective randomized trial is being prepared in our institution to confirm these results.

[Prevalence of pressure sores in a university hospital in 2003]. / L'escarre à l'hôpital en 2003: enquête de prévalence un jour donné.

BACKGROUND: To determine the prevalence of pressure sores in a university hospital and to assess the risk of developing a pressure sore. METHODS: A one-day survey was performed in all hospitalized patients, day hospital excepted. The Garches scale was used to assess the severity of pressure sores and the Braden scale was used to measure the patient's risk for the development of pressure ulcers. RESULTS: One thousand six hundred and eleven patients were included, mean age was 62+/-23 years and 53.3% were over 65 years old. In hospitalized patients, 64% were in acute care, 29% in intermediate medicine and long-term care and 7% in intensive care units. We have found 675 pressure sores in 268 patients, mean age of 76 years; 263 decubitus ulcers were acquired during hospitalization. The most frequent sites were heels (46%) and sacrum (26%). Stage 1 pressure ulcers showed 33% of the total. The total prevalence was 16.6%, 95% CI (14.9-18.6), the hospital acquired pressure sores prevalence was 7.5%, all stages included. A Braden score less than or equal to 15 was found in 29.1% of hospitalized patients. Standard mattresses were used in 37% of patients with pressure sores. Multivariate analysis showed that age and a Braden score less than or equal to 15 were significantly associated with pressure sores. CONCLUSION: Pressure sores are still an important problem in hospital; occurrence must be considered as an iatrogenic event and management requires a multidisciplinary approach.