Délégation Paris 6
governmentParis, France
Research output, citation impact, and the most-cited recent papers from Délégation Paris 6 (France). Aggregated across the NobleBlocks index of 300M+ scholarly works.
Top-cited papers from Délégation Paris 6
) is then derived that uniquely defines intermolecular interaction regions. An attractive feature of the IGM methodology is to provide a workflow that automatically generates data composed solely of intermolecular interactions for drawing the corresponding 3D isosurface representations.
Colloidal synthesis offers a route to nanoparticles (NPs) with controlled composition and structural features. This Perspective describes the use of polyvinylpyrrolidone (PVP) to obtain such nanostructures. PVP can serve as a surface stabilizer, growth modifier, nanoparticle dispersant, and reducing agent. As shown with examples, its role depends on the synthetic conditions. This dependence arises from the amphiphilic nature of PVP along with the molecular weight of the selected PVP. These characteristics can affect nanoparticle growth and morphology by providing solubility in diverse solvents, selective surface stabilization, and even access to kinetically controlled growth conditions. This Perspective includes discussions of the properties of PVP-capped NPs for surface enhanced Raman spectroscopy (SERS), assembly, catalysis, and more. The contribution of PVP to these properties as well as its removal is considered. Ultimately, the NPs accessed through the use of PVP in colloidal syntheses are opening new applications, and the concluding guidelines provided herein should enable new nanostructures to be accessed facilely.
The increasing amount of electronic word of mouth (eWOM) has significantly affected the way consumers make purchase decisions. Empirical studies have established an effect of eWOM on sales but disagree on which online platforms, products, and eWOM metrics moderate this effect. The authors conduct a meta-analysis of 1,532 effect sizes across 96 studies covering 40 platforms and 26 product categories. On average, eWOM is positively correlated with sales (.091), but its effectiveness differs across platform, product, and metric factors. For example, the effectiveness of eWOM on social media platforms is stronger when eWOM receivers can assess their own similarity to eWOM senders, whereas these homophily details do not influence the effectiveness of eWOM for e-commerce platforms. In addition, whereas eWOM has a stronger effect on sales for tangible goods new to the market, the product life cycle does not moderate the eWOM effectiveness for services. With respect to the eWOM metrics, eWOM volume has a stronger impact on sales than eWOM valence. In addition, negative eWOM does not always jeopardize sales, but high variability does.
The 1996 Five-Factor Score (FFS) for systemic necrotizing vasculitides (polyarteritis nodosa [PAN], microscopic polyangiitis [MPA], and Churg-Strauss syndrome [CSS]) is used to evaluate prognosis at diagnosis. In the current study we revisited the FFS, this time including Wegener granulomatosis (WG).We analyzed clinical, laboratory, and immunologic manifestations present at diagnosis of systemic necrotizing vasculitides for 1108 consecutive patients registered in the French Vasculitis Study Group database. All patients met the American College of Rheumatology and Chapel Hill nomenclature criteria. Univariable and multivariable analyses yielded the 2009 FFS for the 4 systemic necrotizing vasculitides.Overall mortality was 19.8% (219/1108); mortality for each of the SNV is listed in descending order: MPA (60/218, 27.5%), PAN (86/349, 24.6%), CSS (32/230, 13.9%), and WG (41/311, 13.2%) (p < 0.001). The following factors were significantly associated with higher 5-year mortality: age >65 years, cardiac symptoms, gastrointestinal involvement, and renal insufficiency (stabilized peak creatinine ≥150 μmol/L). All were disease-specific (p < 0.001); the presence of each was accorded +1 point. Ear, nose, and throat (ENT) symptoms, affecting patients with WG and CSS, were associated with a lower relative risk of death, and their absence was scored +1 point (p < 0.001). Only renal insufficiency was retained (not proteinuria or microscopic hematuria) as impinging on outcome. According to the 2009 FFS, 5-year mortality rates for scores of 0, 1, and ≥2 were 9%, 21% (p < 0.005), and 40% (p < 0.0001), respectively.The revised FFS for the 4 systemic necrotizing vasculitides now comprises 4 factors associated with poorer prognosis and 1 with better outcome. The retained items demonstrate that visceral involvement weighs heavily on outcome. The better WG prognosis for patients with ENT manifestations, even for patients with other visceral involvement, compared with the prognosis for those without ENT manifestations, probably reflects WG phenotype heterogeneity.
The production of sustainable hydrogen with water electrolyzers is envisaged as one of the most promising ways to match the continuously growing demand for renewable electricity storage. While so far regarded as fast when compared to the oxygen evolution reaction (OER), the hydrogen evolution reaction (HER) regained interest in the last few years owing to its poor kinetics in alkaline electrolytes. Indeed, this slow kinetics not only may hinder the foreseen development of the anionic exchange membrane water electrolyzer (AEMWE), but also raises fundamental questions regarding the parameters governing the reaction. In this perspective, we first briefly review the fundamentals of the HER, emphasizing how studies performed on model electrodes allowed for achieving a good understanding of its mechanism under acidic conditions. Then, we discuss how the use of physical descriptors capturing the sole properties of the catalyst is not sufficient to describe the HER kinetics under alkaline conditions, thus forcing the catalysis community to adopt a more complex picture taking into account the electrolyte structure at the electrochemical interface. This work also outlines new techniques, such as spectroscopies, molecular simulations, or chemical approaches that could be employed to tackle these new fundamental challenges, and potentially guide the future design of practical and cheap catalysts while also being useful to a wider community dealing with electrochemical energy storage devices using aqueous electrolytes.
= 21,649) to study gender differences in COVID-19-related beliefs and behaviors. We show that women are more likely to perceive COVID-19 as a very serious health problem, to agree with restraining public policy measures, and to comply with them. Gender differences in attitudes and behavior are sizable in all countries. They are accounted for neither by sociodemographic and employment characteristics nor by psychological and behavioral factors. They are only partially mitigated for individuals who cohabit or have direct exposure to the virus. We show that our results are not due to differential social desirability bias. This evidence has important implications for public health policies and communication on COVID-19, which may need to be gender based, and it unveils a domain of gender differences: behavioral changes in response to a new risk.
Following their discovery in 1961, it was speculated that satellite cells were dormant myoblasts, held in reserve until required for skeletal muscle repair. Evidence for this accumulated over the years, until the link between satellite cells and the myoblasts that appear during muscle regeneration was finally established. Subsequently, it was demonstrated that, when grafted, satellite cells could also self-renew, conferring on them the coveted status of 'stem cell'. The emergence of other cell types with myogenic potential, however, questioned the precise role of satellite cells. Here, we review recent recombination-based studies that have furthered our understanding of satellite cell biology. The clear consensus is that skeletal muscle does not regenerate without satellite cells, confirming their pivotal and non-redundant role.
Covering: up to June 2020Ribosomally-synthesized and post-translationally modified peptides (RiPPs) are a large group of natural products. A community-driven review in 2013 described the emerging commonalities in the biosynthesis of RiPPs and the opportunities they offered for bioengineering and genome mining. Since then, the field has seen tremendous advances in understanding of the mechanisms by which nature assembles these compounds, in engineering their biosynthetic machinery for a wide range of applications, and in the discovery of entirely new RiPP families using bioinformatic tools developed specifically for this compound class. The First International Conference on RiPPs was held in 2019, and the meeting participants assembled the current review describing new developments since 2013. The review discusses the new classes of RiPPs that have been discovered, the advances in our understanding of the installation of both primary and secondary post-translational modifications, and the mechanisms by which the enzymes recognize the leader peptides in their substrates. In addition, genome mining tools used for RiPP discovery are discussed as well as various strategies for RiPP engineering. An outlook section presents directions for future research.
Objective Effective communication of simple, clear information to families of intensive care unit (ICU) patients is a vital component of quality care. The purpose of this study was to identify factors associated with poor comprehension by family members of the status of ICU patients. Design Prospective study. Setting University-affiliated medical intensive care unit. Patients and Methods A total of 102 patients admitted to an ICU for >2 days. Intervention The representatives of 76 patients who were visited by at least one person during their ICU stay were interviewed. Results Mean patient age was 54 ± 17 yrs and mean Simplified Acute Physiology Score II at admission was 40 ± 20. The representative was the spouse in 47 cases (62%). Among representatives, 25 (33%) were of foreign descent and 12 (16%) did not speak French. Mean duration of the first meeting with a physician was 10 ± 6 mins. In 34 cases (54%), the representative failed to comprehend the diagnosis, prognosis, or treatment of the patient. Factors associated with poor comprehension by representatives included patient-related, family-related, and physician- related factors. Patient-related factors included age <50 yrs (p = .03), unemployment (p = .01), referral from a hematology or oncology ward (p = .006), admission for acute respiratory failure (p = .005) or coma (p = .01), and a relatively favorable prognosis (p = .04). Family-related factors were foreign descent (p = .007), no knowledge of French (p = .03), representative not the spouse (p = .03), and no healthcare professional in the family (p = .01). Physician-related factors were first meeting with representative <10 mins (p = .03) and failure to give the representative an information brochure (p = .02). Moreover, after the first meeting, caregivers accurately predicted poor comprehension by representatives (p = .03). Conclusions Patient information is frequently not communicated effectively to family members by ICU physicians. Physicians should strive to identify patients and families who require special attention and to determine how their personal style of interrelating with family members may impair communication.
Mixed-metal MOFs are metal-organic frameworks that contain at least 2 different metal ions as nodes of their frameworks. They are prepared relatively easily by either a one-pot synthesis with a synthesis mixture containing the different metals, or by a post-synthetic ion-exchange method by soaking a monometallic MOF in a concentrated solution of a different (but compatible) metal-ion. More difficult is the accurate characterization of these materials. Is the formed product a mixture of monometallic MOFs or indeed a MOF with different metallic nodes? Are the metals randomly distributed or do they form domains? What is the oxidation state of the metals? How do the metals mutually influence each other, and impact the material's performance? Advanced characterization techniques are required e.g. X-ray absorption spectroscopy, magnetic resonance and electron microscopy. Computational tools at multiple scales are also often applied. In almost every case, a judicious choice of several techniques is required to unambiguously characterize the mixed-metal MOF. Although still in their infancy, several applications are emerging for mixed-metal MOFs, that improve on conventional monometallic MOFs. In the field of gas sorption and storage, especially the stability and affinity towards the target gases can be largely improved by introducing a second metal ion. In the case of flexible MOFs, the breathing behavior, and in particular the pressure at which the MOF opens, can be tailored. In heterogeneous catalysis, new cascade and tandem reactions become possible, with particular focus on reactions where the two metals in close proximity truly form a mixed-metal transition state. The bimetallic MOF should have a clear benefit over a mixture of the respective monometallic MOFs, and bimetallic enzymes can be a huge source of inspiration in this field. Another very promising application lies in the fields of luminescence and sensing. By tuning the lanthanide metals in mixed-metal lanthanide MOFs and by using the organic linkers as antennae, novel smart materials can be developed, acting as sensors and as thermochromic thermometers. Of course there are also still open challenges, as also mixed-metal MOFs do not escape the typical drawbacks of MOFs, such as low stability in moisture and possible metal leaching in liquids. The ease of synthesis of mixed-metal MOFs is a large bonus. In this critical review, we discuss in detail the synthesis, characterization, computational work and applications of mixed-metal MOFs.
OBJECTIVE: Anxiety and depression may have a major impact on a person's ability to make decisions. Characterization of symptoms that reflect anxiety and depression in family members visiting intensive care patients should be of major relevance to the ethics of involving family members in decision-making, particularly about end-of-life issues. DESIGN: Prospective multicenter study. SETTING: Forty-three French intensive care units (37 adult and six pediatric); each unit included 15 patients admitted for longer than 2 days. PATIENTS: Six hundred thirty-seven patients and 920 family members. INTERVENTIONS: Intensive care unit characteristics and data on the patient and family members were collected. Family members completed the Hospital Anxiety and Depression Scale to allow evaluation of the prevalence and potential factors associated with symptoms of anxiety and depression. MEASUREMENTS AND MAIN RESULTS: Of 920 Hospital Anxiety and Depression Scale questionnaires that were completed by family members, all items were completed in 836 questionnaires, which formed the basis for this study. The prevalence of symptoms of anxiety and depression in family members was 69.1% and 35.4%, respectively. Symptoms of anxiety or depression were present in 72.7% of family members and 84% of spouses. Factors associated with symptoms of anxiety in a multivariate model included patient-related factors (absence of chronic disease), family-related factors (spouse, female gender, desire for professional psychological help, help being received by general practitioner), and caregiver-related factors (absence of regular physician and nurse meetings, absence of a room used only for meetings with family members). The multivariate model also identified three groups of factors associated with symptoms of depression: patient-related (age), family-related (spouse, female gender, not of French descent), and caregiver-related (no waiting room, perceived contradictions in the information provided by caregivers). CONCLUSIONS: More than two-thirds of family members visiting patients in the intensive care unit suffer from symptoms of anxiety or depression. Involvement of anxious or depressed family members in end-of-life decisions should be carefully discussed.
We made a retrospective evaluation of clinical and radiologic features, treatment, and outcome of Erdheim-Chester disease, a rare non-Langerhans cell histiocytosis. We had 7 patients coming from 3 French teaching hospitals and reviewed 52 cases from the literature. These cases were considered to have Erdheim-Chester disease when they had either typical bone radiographs (symmetrical long bones osteosclerosis) and/or histologic criteria disclosing histiocytic infiltration without features for Langerhans cell histiocytosis (no S-100 protein, no intracytoplasmic Birbeck granules). Ages at diagnosis ranged from 7 to 84 years (mean +/- SD = 53 +/- 14 yr) with a male/female ratio of 33/26. Bone pain was the most frequent clinical sign (28/59), mostly located in the lower limbs. Exophthalmos and diabetes insipidus were found in respectively 16/59 and 17/59 patients. General symptoms (fever, weight loss) and "xanthomas" (mainly located on the eyelids) were present in 11/59 patients. Retroperitoneal involvement was found in 17/59 patients. Skeletal X-ray showed typical osteosclerosis of the diaphysis of the long bones in 45/59 patients. Bone radiographs showed osteolytic lesions of the flat bones (skull, ribs) in 8 patients. Histologic diagnosis was performed after a bone biopsy (28 patients), a retroorbital biopsy (9 patients), and/or a biopsy of the retroperitoneal infiltration or the kidney (11 patients). Six of our 7 patients but only 5 of 52 patients from the literature had the complete histologic criteria, disclosing no Birbeck granules or S-100 immunostaining. In other cases, histologic results usually described a xanthogranulomatous infiltration by foamy histiocytes nested in fibrosis. Treatment was corticotherapy (20/59), chemotherapy (8/59), radiotherapy (6/59), surgery (3/59) and immunotherapy (1 patient). Twenty-two patients died after a mean follow-up of 32 +/- 30 mo (range, 3-120 mo). In conclusion, Erdheim-Chester disease may be confused with Langerhans cell histiocytosis as it sometimes shares the same clinical (exophthalmos, diabetes insipidus) or radiologic (osteolytic lesions) findings. However, it also appears to have distinctive features. Patients are older and have a worse prognosis than those with Langerhans cell histiocytosis, and the diagnosis relies on the association of specific radiologic and histologic findings.
A selection of dynamic chemistries is highlighted, with a focus on the reaction mechanisms of molecular network rearrangements, and on how mechanistic profiles can be related to the mechanical and physicochemical properties of polymer materials.
Among all the software packages available for discriminant analyses based on projection to latent structures (PLS-DA) or orthogonal projection to latent structures (OPLS-DA), SIMCA (Umetrics, Umeå Sweden) is the more widely used in the metabolomics field. SIMCA proposes many parameters or tests to assess the quality of the computed model (the number of significant components, R2, Q2, pCV-ANOVA, and the permutation test). Significance thresholds for these parameters are strongly application-dependent. Concerning the Q2 parameter, a significance threshold of 0.5 is generally admitted. However, during the last few years, many PLS-DA/OPLS-DA models built using SIMCA have been published with Q2 values lower than 0.5. The purpose of this opinion note is to point out that, in some circumstances frequently encountered in metabolomics, the values of these parameters strongly depend on the individuals that constitute the validation subsets. As a result of the way in which the software selects members of the calibration and validation subsets, a simple permutation of dataset rows can, in several cases, lead to contradictory conclusions about the significance of the models when a K-fold cross-validation is used. We believe that, when Q2 values lower than 0.5 are obtained, SIMCA users should at least verify that the quality parameters are stable towards permutation of the rows in their dataset.
After about three decades of development, the polyol process is now widely recognized and practised as a unique soft chemical method for the preparation of a large variety of nanoparticles which can be used in important technological fields. It offers many advantages: low cost, ease of use and, very importantly, already proven scalability for industrial applications. Among the different classes of inorganic nanoparticles which can be prepared in liquid polyols, metals were the first reported. This review aims to give a comprehensive account of the strategies used to prepare monometallic nanoparticles and multimetallic materials with tailored size and shape. As regards monometallic materials, while the preparation of noble as well as ferromagnetic metals is now clearly established, the scope of the polyol process has been extended to the preparation of more electropositive metals, such as post-transition metals and semi-metals. The potential of this method is also clearly displayed for the preparation of alloys, intermetallics and core-shell nanostructures with a very large diversity of compositions and architectures.
This paper aims to identify robust descriptors to rationalize the anionic redox mechanism in layered Li-rich TM-oxides using conceptual tools, such as atomic charges, orbital interactions and crystal orbital overlap populations (COOP), based on first-principles DFT calculations.
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From January 1996 to January 1997, 321 patients with an average age of 46 +/- 16 years and chronically infected with hepatitis C virus (HCV) were prospectively enrolled in a study designed to determine the prevalence of extrahepatic manifestations associated with HCV infection in a large cohort of HCV patients, to identify associations between clinical and biologic manifestations, and to compare the results obtained in human immunodeficiency virus (HIV)-positive versus HIV-negative subsets. In a cross-sectional study, clinical extrahepatic manifestations, viral coinfections with HIV and/or hepatitis B virus, connective tissue diseases, and a wide panel of autoantibodies were assessed. Thirty-eight percent (122/321) of patients presented at least 1 clinical extrahepatic manifestation including arthralgia (60/321, 19%), skin manifestations (55/321, 17%), xerostomia (40/321, 12%), xerophthalmia (32/321, 10%), and sensory neuropathy (28/321, 9%). Main biologic abnormalities were mixed cryoglobulins (110/196, 56%), thrombocytopenia (50/291, 17%), and the presence of the following autoantibodies: antinuclear (123/302, 41%), rheumatoid factor (107/280, 38%), anticardiolipin (79/298, 27%), antithyroglobulin (36/287, 13%) and antismooth muscle cell (27/288, 9%). At least 1 autoantibody was present in 210/302 (70%) of sera. By multivariate logistic regression analysis, 4 parameters were significantly associated with cryoglobulin positivity: systemic vasculitis (p = 0.01, odds ratio OR[ = 17.3), HIV positivity (p = 0.0006, OR = 10.2), rheumatoid factor positivity (p = 0.01, OR = 2.8), and sicca syndrome (p = 0.03, OR = 0.27). A definite connective tissue disease was noted in 44 patients (14%), mainly symptomatic mixed cryoglobulinemia and systemic vasculitis, HIV coinfection (23%) was associated with 3 parameters: anticardiolipin (p = 0.003, OR = 4.18), thrombocytopenia (p = 0.01, OR = 3.56), and arthralgia or myalgia (p = 0.017, OR = 0.23). HIV-positive patients presented more severe histologic lesions (p = 0.0004). Extrahepatic clinical manifestations in HCV patients involve primarily the skin and joints. The most frequent immunologic abnormalities include mixed cryoglobulins, rheumatoid factor, antinuclear, anticardiolipin, and antithyroglobulin antibodies. Cryoglobulin positivity is associated with systemic vasculitis and rheumatoid factor and HIV positivity. HIV coinfection is associated with arthralgia or myalgia, anticardiolipin antibodies, and thrombocytopenia.
Cell refractive index is a key biophysical parameter, which has been extensively studied. It is correlated with other cell biophysical properties including mechanical, electrical and optical properties, and not only represents the intracellular mass and concentration of a cell, but also provides important insight for various biological models. Measurement techniques developed earlier only measure the effective refractive index of a cell or a cell suspension, providing only limited information on cell refractive index and hence hindering its in-depth analysis and correlation. Recently, the emergence of microfluidic, photonic and imaging technologies has enabled the manipulation of a single cell and the 3D refractive index of a single cell down to sub-micron resolution, providing powerful tools to study cells based on refractive index. In this review, we provide an overview of cell refractive index models and measurement techniques including microfluidic chip-based techniques for the last 50 years, present the applications and significance of cell refractive index in cell biology, hematology, and pathology, and discuss future research trends in the field, including 3D imaging methods, integration with microfluidics and potential applications in new and breakthrough research areas.
Polypyridyl transition metal complexes represent one of the more thoroughly studied classes of molecular catalysts towards CO<sub>2</sub> reduction to date.