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Approximately 25% of cancers are preceded by chronic inflammation that occurs at the site of tumor development. However, whether this multifactorial oncogenic process, which commonly occurs in the intestines, can be initiated by a specific immune cell population is unclear. Here, we show that an intestinal T cell subset, derived from interleukin-17 (IL-17)-producing helper T (TH17) cells, induces the spontaneous transformation of the intestinal epithelium. This subset produces inflammatory cytokines, and its tumorigenic potential is not dependent on IL-17 production but on the transcription factors KLF6 and T-BET and interferon-γ. The development of this cell type is inhibited by transforming growth factor-β1 (TGFβ1) produced by intestinal epithelial cells. TGFβ signaling acts on the pretumorigenic TH17 cell subset, preventing its progression to the tumorigenic stage by inhibiting KLF6-dependent T-BET expression. This study therefore identifies an intestinal T cell subset initiating cancer.

The optimal calorie and protein intakes at the acute phase of severe critical illness remain unknown. We hypothesised that early calorie and protein restriction improved outcomes in these patients, compared with standard calorie and protein targets.

In most countries, the use of precautionary allergen labeling (PAL) is not governed by regulation. PAL was initially identified as a judicious risk management measure to address instances of “unavoidable” cross-contact with priority food allergens during food processing. However, PAL has gradually been devalued in part due to overuse and inconsistent application by the food industry. Currently, most food products do not contain detectable allergen residue or contain only low concentrations of residue of the allergens declared using PAL; however, occasionally, high concentrations of allergen residue are reported, rendering it an ineffective risk communication tool for allergic consumers. In this context, several reasons exist that make the consumption of products bearing a PAL statement not advisable for people with food allergies. The main reason is that the risk is generally not correlated with the statement used by manufacturers. Because of the increased use of PAL on prepackaged food products, and to maximize food choices for allergic individuals, health care professionals increasingly advise some patients considered to be “not highly allergic” to consume products bearing a PAL statement. This article explains why the consumption of products with PAL is not advisable without having a full clinical evaluation and knowledge that an allergen risk assessment has been conducted. It also discusses the perspectives for a better use of PAL on the basis of the recent Food and Agricultural Organization/World Health Organization recommendations on food allergens.

The present study investigates the tensile behavior of the two bimetallic composite wires Cu-Al and Fe-Al. The purpose is to understand the deviation their tensile strengths show from the Rule of Mixtures’ prediction. To that end, an experimental-numerical approach was adopted. Following tensile testing of the above cold-drawn composite wires, the manufacturing process (wire drawing) was simulated via finite element analysis. The prominent role of processing-induced residual stresses on the yield strength of cold-drawn products is known. Therefore, a discussion based on the axial tensile residual stress profile was developed. It was concluded that the higher-magnitude-near-surface tensile residual stresses in the Fe-Al wire causes its tensile curve to show a negative deviation from the Rule of Mixtures (RoM). The Cu-Al wire, on the contrary, exhibits a slight positive deviation.

Coupling additive manufacturing with milling changes the interaction between the cutting tool and workpiece. The resulting effect on tool wear and surface integrity is poorly understood. Maraging steel printed via powder bed fusion was peripherally milled in the presence of un-melted metallic powder surrounding the printed part. Areal surface parameters, microhardness, and tool wear were analyzed. Results showed that milling within powder decreased surface roughness and introduced a weak orthogonal texture between the feed marks and printed layers. Milling without powder caused a more pronounced inclined texture. Milling within powder accelerated flank wear while milling without powder accelerated crater wear.

The “industry 4.0” transition requires a digital chain capable of self-adapting face to evolving and increasingly complex organizational, informational and technological contexts. For this need, this paper discusses the incentive to develop new kind of connectors, intelligent and pragmatic, as a unique and universal interface to support interoperability between different types of technological and software systems in various collaborative processes in the enterprise of the future.

We studied the kinetics and mechanism of the dehydration reaction of calcium sulfate dihydrate to hemihydrate under controlled temperature and water vapor partial pressure. From kinetic and reaction rate curves obtained using thermogravimetric analysis (TGA) under isothermal and isobaric conditions, we determined the overall behavior of this dehydration reaction and the effects of the system’s intensive variables on its kinetics. We observed that the reactions take place with an initial induction period that decreases with increasing temperature, followed by a sigmoidal mass loss controlled by both nucleation and growth processes. Characterization of our samples at different points of the reaction allowed us to observe and confirm a surface nucleation process followed by isotropic growth of the nuclei with inward development of the solid product. We then employed the Mampel kinetic model based on the observed experimental results considering the physical nature of the investigated transformation and the real geometry of the particles. From this model, we obtained sets of kinetic parameters for the nucleation and growth processes and their evolution with temperature. We then proposed physicochemical mechanisms for both processes, and they were considered to interpret the kinetic parameters obtained previously. The mechanistic analysis of the system allowed determination of the effects of both temperature and water vapor pressure on the kinetic behavior of the reaction, which corresponds to a novel approach for the dehydration reaction of calcium sulfate dihydrate. The universal kinetic approach used to treat this chemical system in this work can be applied for studying the dehydration of other ionic hydrates.

Los miembros del complejo Trichophyton mentagrophytesrepresentan el segundo grupo en frecuencia de aislamiento de dermatofitos, luego de Trichophyton rubrum. El citado complejo comprende 3grupos principales: 1)Trichophyton benhamiaey especies relacionadas; 2)Trichophyton simiiy 2especies relacionadas, Trichophyton quinckeanumy Trichophyton schoenleinii, y 3)T. mentagrophytes, Trichophyton interdigitaley especies relacionadas. Todos estos organismos son difíciles de identificar a través de la morfofisiología. Se presenta en este informe un estudio descriptivo de 17 cepas clínicas aisladas e identificadas en el Laboratorio de Micología de la Universidad de Valparaíso como pertenecientes al complejo T. mentagrophytes, junto con la caracterización de 3cepas de referencia (T. mentagrophytesCBS 318.56, T. interdigitaleCBS 428.63, Trichophyton erinaceiCBS 511.73), con el objetivo de clasificarlas a nivel de especie. Se realizaron pruebas morfofisiológicas y moleculares por análisis de curvas de meltingde alta resolución (high resolution melting analysis) y secuenciación de regiones ITS. Fenotípicamente, se identificaron 3especies incluidas en el complejo. Los análisis moleculares reclasificaron todas las cepas como pertenecientes a T. interdigitale. En conclusión, no se lograron establecer patrones morfofisiológicos confiables para poder diferenciar entre las especies del complejo.

ObjectiveCarotid atherosclerotic plaques are a source of emboli for stroke. ‘Unstable’ carotid atherosclerotic plaques may have intraplaque haemorrhages, neovessels, prevalent macrophages, excessive calcium deposits, a large lipid core and a thin fibrous cap. Regular physical activity (PA) may lower the risk of plaques becoming unstable. We evaluated the association of both PA and sedentary behaviour (SB) with carotid plaque histopathology.Methods90 asymptomatic patients who were undergoing carotid endarterectomy for carotid artery narrowing identified on ultrasound reported their PA and SB by questionnaires. We calculated PA intensity in MET (metabolic equivalent of task)-min/week. For analysis, the population was divided into tertiles according to PA (T1PA: the less PA patients; T2PA: the intermediate PA patients; T3PA: the most physically active patients) (T1PA900 and <900 MET-min/week, respectively). All the other features that associate with plaque instability (eg, neovessels, macrophages, etc) did not differ by level of PA or SB.ConclusionIn this cross-sectional study of asymptomatic patients who underwent endarterectomy (i) higher reported PA, (ii) intensity of PA and (iii) lower reported SB were associated with lower prevalence of intraplaque haemorrhage. This could be a mechanism whereby PA protects against cerebrovascular disease (stroke) and death.

We report a theoretical study that elaborates the influence of the polarization state of both the pump and the probe pulse in ultrafast coherent vibrational ladder climbing experiments in the mid-infrared. Whereas a subensemble in a randomly oriented sample of molecules is excited by the pump pulse in this multiphoton process, further inhomogeneities such as the spatial profile of the laser beams, the longitudinal attenuation in the sample, and the probe beam polarization have to be taken into account. Analytical expressions for a density function describing the number of molecules that are exposed to an effective pump intensity are introduced, and the variation of the population distribution and the actual transient absorption signal in dependence on the polarization-state combinations for pump and probe pulse are discussed in detail. In simulations on the model system carboxy-hemoglobin, it is demonstrated that the polarization states play important roles both for exciting a certain population distribution and for actually observing it. In particular, it will be discussed under which conditions experimental data indicates a population inversion.

ABSTRACTSupplementation with probiotics has emerged as a promising therapeutic tool to manage metabolic diseases. We investigated the effects of a mix of Bifidobacterium animalissubsp. lactisLA804 and Lactobacillus gasseriLA806 on high-fat (HF) diet -induced metabolic disease in mice. Supplementation with the probiotic mix in HF diet-fed mice (HF-Pr2) reduced weight and fat mass gains, decreased hepatic lipid accumulation, and lowered plasma triglyceride peak during an oral lipid tolerance test. At the molecular level, the probiotic mix protected against HF-induced rise in mRNA levels of genes related to lipid uptake, metabolism, and storage in the liver and white adipose tissues, and strongly decreased mRNA levels of genes related to inflammation in the white adipose tissue and to oxidative stress in the liver. Regarding intestinal homeostasis, the probiotic mix did not prevent HF-induced gut permeability but slightly modified microbiota composition without correcting the dysbiosis induced by the HF diet. Probiotic supplementation also modified the cecal bile acid (BA) profile, leading to an increase in the Farnesoid-X-Receptor (FXR) antagonist/agonist ratio between BA species. In agreement, HF-Pr2 mice exhibited a strong inhibition of FXR signaling pathway in the ileum, which was associated with lipid metabolism protection. This is consistent with recent reports proposing that inhibition of intestinal FXR activity could be a potent mechanism to overcome metabolic disorders. Altogether, our results demonstrate that the probiotic mix evaluated, when administered preventively to HF diet-fed mice could limit obesity and associated lipid metabolism disorders, likely through the inhibition of FXR signaling in the intestinal tract.

We employ a rigorous thermodynamic modeling approach to investigate the water adsorption phenomena on two calcium sulfate compounds, AIII-CaSO4and CaSO4·0.5H2O. In part 1 of this work (Ind. Eng. Chem. Res., 2019, DOI: 10.1021/acs.iecr.9b00856), we prepared these two products by the dehydration of synthetic CaSO4·2H2O and obtained quantitative adsorption data as a function of the temperature and water vapor partial pressure. In this part, we develop macroscopic solution models (ideal and nonideal) to model monolayer adsorption on AIII-CaSO4. This allowed the calculation of the energies of adsorption for this phenomenon, evidencing a physisorption mechanism. For the CaSO4·0.5H2O, we interpreted the water adsorption using a multilayer adsorption model (BET model). For both materials, we showed that nitrogen adsorption data was not sufficient to represent their entire surface areas and porosity profiles compared to their water vapor sorption capacity.

The calcium sulfate–water vapor system is of great scientific and technological importance due to its applications in several fields such as the construction materials industry, geology, and planetary sciences. While much effort has been concentrated during the past decades on characterizing the crystallographic structure of the different calcium sulfate polymorphs, some questions concerning their thermodynamic aspects as phase equilibria and their capability to increase their overall water content continuously beyond structural water content seem to have been left aside. Nevertheless, the comprehension of these aspects is of the utmost importance if we want to understand this chemical system fully. The present two-part work investigates these phenomena experimentally and by a thermodynamic modeling approach. In this first part, we develop a rigorous experimental protocol by thermogravimetric analysis under controlled temperature and water vapor partial pressure. We use this protocol to obtain thermodynamic equilibrium values for the overall water content of calcium sulfate hydrates. To ensure that the equilibrium was reached, we verified that these values could be obtained by distinct thermodynamic paths. With the equilibrium data, we were able to propose an updated equilibrium curve between soluble anhydrite AIII-CaSO4and CaSO4·0.5H2O and estimate the thermodynamic parameters ΔrH° = (35.5 ± 1.0) kJ·mol–1and ΔrS° = (80.0 ± 2.8) J·mol–1·K–1. After that, we were able to quantify the extent of water adsorption as a function of (T, PH2O), and we observed that it could represent a significant part of the overall water content of calcium sulfates.

Los ambientes internos son un hábitat protector importante, donde el hombre reside o trabaja la mayor parte de su tiempo. Muchos de estos ambientes carecen de buena ventilación, lo que influye en la composición de sus comunidades microbianas y, en especial, de la fúngica. El objetivo de este estudio es comunicar la presencia de Aspergillusde la sección Candidi en ambientes internos de la Escuela de Medicina de la Universidad de Valparaíso, Chile, y destacar su rol ecológico y su importancia en micología médica. Se efectuó la clasificación morfofisiológica y molecular de dichos aislamientos. Se realizó un muestreo no volumétrico ambiental en agar papa glucosado (PDA) mediante la exposición de 2 placas en 10 diferentes ambientes internos para seleccionar las especies de Aspergillus. Se efectuaron subcultivos en agar Czapek con extracto de levadura (CYA), agar extracto de malta (MEA) y agar creatina sacarosa (CREA) solo para las especies de esporas blancas, para su identificación morfofisiológica y posteriormente molecular. De 20 muestras analizadas, en solo una se aisló un miembro de Aspergillusperteneciente a la sección Candidi. Sobre la base de sus características morfológicas y moleculares, se clasificó a este aislamiento como AspergillustriticiMehrotra & Basu. Se describe su ecología y se discute su importancia médica.

Improved plant varieties are important in our attempts to face the challenges of a growing human population and limited planet resources. Plant breeding relies on meiotic crossovers to combine favourable alleles into elite varieties1. However, meiotic crossovers are relatively rare, typically one to three per chromosome2, limiting the efficiency of the breeding process and related activities such as genetic mapping. Several genes that limit meiotic recombination were identified in the model species Arabidopsis thaliana2. Mutation of these genes in Arabidopsisinduces a large increase in crossover frequency. However, it remained to be demonstrated whether crossovers could also be increased in crop species hybrids. We explored the effects of mutating the orthologues of FANCM3, RECQ44or FIGL15on recombination in three distant crop species, rice (Oryza sativa), pea (Pisum sativum) and tomato (Solanum lycopersicum). We found that the single recq4mutation increases crossovers about three-fold in these crops, suggesting that manipulating RECQ4may be a universal tool for increasing recombination in plants. Enhanced recombination could be used with other state-of-the-art technologies such as genomic selection, genome editing or speed breeding6to enhance the pace and efficiency of plant improvement.

The aim of this study was to evaluate episiotomy technique, in particular suture angles, and any correlation between suture angle and severe perineal tears.

The endocrine-derived hormone fibroblast growth factor (FGF) 19 has recently emerged as a potential target for treating metabolic disease. Given that skeletal muscle is a key metabolic organ, we explored the role of FGF19 in that tissue. Here we report a novel function of FGF19 in regulating skeletal muscle mass through enlargement of muscle fiber size, and in protecting muscle from atrophy. Treatment with FGF19 causes skeletal muscle hypertrophy in mice, while physiological and pharmacological doses of FGF19 substantially increase the size of human myotubes in vitro. These effects were not elicited by FGF21, a closely related endocrine FGF member. Both in vitro and in vivo, FGF19 stimulates the phosphorylation of the extracellular-signal-regulated protein kinase 1/2 (ERK1/2) and the ribosomal protein S6 kinase (S6K1), an mTOR-dependent master regulator of muscle cell growth. Moreover, mice with a skeletal-muscle-specific genetic deficiency of β-Klotho (KLB), an obligate co-receptor for FGF15/19 (refs. 2,3), were unresponsive to the hypertrophic effect of FGF19. Finally, in mice, FGF19 ameliorates skeletal muscle atrophy induced by glucocorticoid treatment or obesity, as well as sarcopenia. Taken together, these findings provide evidence that the enterokine FGF19 is a novel factor in the regulation of skeletal muscle mass, and that it has therapeutic potential for the treatment of muscle wasting.

The effect of stresses on the magnetic behaviour of polycrystalline ferrites has been investigated by the use of experiments and a multiscale model. This model is based upon 3 scales: the magnetic domain, the single crystal and the polycrystal. At the scale of the magnetic domain, a minimisation of the potential energy (composed of field energy, anisotropy energy and magneto-elastic energy) gives the orientation of magnetisation under the effect of magnetic field, stresses, and crystal orientation. At the scale of the single crystal, the volume fractions of domains of different orientations are computed from their respective energies through a balance equation that introduces two adjusting parameters. The isotropic polycrystalline behaviour is deduced from the averaging of the behaviour of a sufficient number of grains (of different crystallographic orientations). The adjusting parameters are identified from the magnetisation response of a ring subjected to two different levels of axial compressive stresses. The model is then used to predict the behaviour of the same ring subjected to different levels of radial compressive loading. The predictions are in good agreement with the experimental results.

La esporotricosis es una infección causada por especies pertenecientes al complejo Sporothrix schenckii. Dependiendo de la especie, estos organismos pueden tener virulencia y formas clínicas diferentes.

L’objectif de cette étude était d’évaluer un programme de formation des internes de gynécologie obstétrique sur un simulateur d’accouchement.

N6-carboxymethyl-NAD (N6-CM-NAD) can be used to immobilize NAD onto a substrate containing terminal primary amines. We previously immobilized N6-CM-NAD onto sepharose beads and showed that Thermotoga maritimaglycerol dehydrogenase could use the immobilized cofactor with cofactor recycling. We now show that Saccharomyces cerevisiaealcohol dehydrogenase, rabbit muscle L-lactate dehydrogenase (type XI), bovine liver L-glutamic dehydrogenase (type III), Leuconostoc mesenteroidesglucose-6-phosphate dehydro-genase, and Thermotoga maritimamannitol dehydrogenase are active with soluble N6-CM-NAD. The products of all enzymes but 6-phospho-D-glucono-1,5-lactone were formed when sepharose-immobilized N6-CM-NAD was recycled by T. maritimaglycerol dehydrogenase, indicating that N6-immobilized NAD is suitable for use by a variety of different dehydrogenases. Observations of the enzyme active sites suggest that steric hindrance plays a greater role in limiting or allowing activity with the modified cofactor than do polarity and charge of the residues surrounding the N6-amine group on NAD.

Studies suggest that individuals of low education and/or income, new Canadians (immigrated <10 years ago), and individuals of Aboriginal identity may have fewer food allergies than the general population. However, given the difficulty in recruiting such populations (hereafter referred to as vulnerable populations), by using conventional survey methodologies, the prevalence of food allergy among these populations in Canada has not been estimated.

The objective of this article is to determine the incidences of immigration and globalization on the French educational values and reforms. To explore these two dimensions, it is necessary to give a historical perspective through the reforms since 1958 to the present and to specify the French educational values through a content analysis of the Extracurricular Educational Activities Act (1984), the Convention on the Rights of the Child (1989), and the two secularism charters (1883 and 2013). The study finds that the education reforms reveal a continuous back-and-forth movement between principles of openness and closeness to new audiences with immigrants and to liberal school policy with PISA and PIRLS results in the context of globalization. The article concludes with major implications: France, with the diversity of religions, reaffirmed the secularism principle in 2013 and got an attitude of closeness. France, with its long history of public service, also has an attitude of openness with liberal reforms issued from international evaluations.

Se informa para Chile el aislamiento de S. pallida complexdesde muestras médicas y del suelo del hogar de una paciente. Los hongos del complejo Sporothrix schenckiipueden causar distintas infecciones.En Chile, los aislamientos médicos y ambientales de este complejo son poco frecuentes. El objetivo de este trabajo fue identificar un agente atípico en un caso de onicomicosis y detectar su presencia en el suelo del jardín del hogar de la paciente. Para esto, las muestras clínicas se obtuvieron por raspado subungueal del primer dedo del pie derecho, y las muestras de suelo, de diferentes sectores del jardín. La identificación de las especies se realizó por morfofisiología y para la confirmación molecular se envió una de las cepas aisladas de la uña de la paciente al CBS (14.062). Se identificó S. pallida complextanto de las muestras de uña como de aquellas provenientes del suelo del jardín.

ABSTRACTRhinoviruses are the most frequent cause of human respiratory infections, and quantitative rhinovirus diagnostic tools are needed for clinical investigations. Although results obtained by real-time reverse-transcription PCR (RT-PCR) assays are frequently converted to viral RNA loads, this presents several limitations regarding accurate virus RNA quantification, particularly given the need to reliably quantify all known rhinovirus genotypes with a single assay. Using an internal extraction control and serial dilutions of an in vitro-transcribed rhinovirus RNA reference standard, we validated a quantitative one-step real-time PCR assay. We then used chimeric rhinovirus genomes with 5'-untranslated regions (5'UTRs) originating from the three rhinovirus species and from one enterovirus to estimate the impact of the 5'UTR diversity. Respiratory specimens from infected patients were then also analyzed. The assay quantification ability ranged from 4.10 to 9.10 log RNA copies/ml, with an estimated error margin of ±10%. This variation was mainly linked to target variability and interassay variability. Taken together, our results indicate that our assay can reliably estimate rhinovirus RNA load, provided that the appropriate error margin is used. In contrast, due to the lack of a universal rhinovirus RNA standard and the variability related to sample collection procedures, accurate absolute rhinovirus RNA quantification in respiratory specimens is currently hardly feasible.

The Club of Rome’s report The Limits to Growth , published in 1972, asserted the necessity to stop economic and demographic growth in order to avoid the collapse of the world system. It summarised several heterogeneous approaches of the future, somewhere between an ecologically alarmist approach and a typically managerial approach of technological forecasting. The report caused a storm in political and academic circles, but it also led to the development of several modelling methods that in turn framed the issue in a new way, swapping a ‘for or against growth’ type of approach for a ‘what type of growth may be desirable’ approach or a ‘how to rethink growth to keep it going’ approach. Among those, the cost-benefit approach of pollution would turn out to be a significant tool to understand climate change.

This paper is aimed at investigating the influence of temperature on mechanical properties and behavior of carbon fiber fabric reinforced polyphenylenesulfide (PPS) laminates subjected to different loadings: tensile, open hole tensile, in‐plane shear, compressive, flexural, interlaminar shear, single‐bolt double lap joint, and single‐bolt single lap joint tests. The resulting experimental database is of the utmost importance for generating design allowables for structures integrating such thermoplastic‐based composites. Depending on the test and the laminate's staking sequence, a temperature increase higher than the glass transition temperature (Tg= 98°C of fiber fabric reinforced PPS laminates softens the matrix behavior and significantly degrades the quality of the adhesion at the fiber/matrix interface, resulting in reduced mechanical properties (in‐plane shear, compressive, flexural and interlaminar shear). However, it does not seem to be detrimental for the tensile and the double lap joint's properties in quasi‐isotropic laminates. In angle‐ply laminates, the ductile behavior of the PPS matrix is exacerbated at high temperature resulting in larger plastic deformations and a lesser hole sensitivity of this material. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 80–95, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20239

Nanodiamond (ND) seeding is a well-established route toward the CVD (chemical vapor deposition) synthesis of diamond ultrathin films. This method is based on the deposition onto a substrate of diamond nanoparticles which act as pre-existing sp3seeds. Here, we report on a straightforward method to disperse diamond nanoparticles on a substrate by taking advantage of the electrostatic interactions between the nanodiamonds and the substrate surface coated with a cationic polymer. This layer-by-layer deposition technique leads to reproducible and homogeneous large-scale nanoparticle deposits independent of the substrate’s nature and shape. No specific functionalization of the nanoparticles is required, and low concentrated solutions can be used. The density of NDs on the substrate can be controlled, as shown by in situ ATR-FTIR (attenuated total reflection Fourier transform infrared) analysis and QCM (quartz crystal microbalance) measurements. Highly dense and compact ND deposits can be obtained, allowing CVD growth of nanocrystalline diamond ultrathin films (70 nm) on various substrates. The synthesis of 3D structured and patterned diamond thin films has also been demonstrated with this method.

The asymmetric reductionof benzylic and heteroaryl ketones to the corresponding (R)‐alcohols using I86A Thermoanaerobacter ethanolicusalcohol dehydrogenase (I86A TeSADH) is described. This single amino acid mutation not only makes the active site of I86A TeSADH able to accommodate more sterically demanding substituents than those accommodated by wild‐type TeSADH, but it also reverses the substrate stereospecificity of TeSADH.

Limited data exist on the economic burden of food allergy (FA).

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RésuméLes sports de rue demeurent trop souvent assimilés à des pratiques marginales et déviantes. Des enquêtes qualitatives et quantitatives, menées par nos soins auprès de skateurs et de basketteurs, insistent sur la diversité et l’ambiguïté des pratiques et des représentations développées dans ces activités auto-organisées dans la ville. À ce niveau, des ambivalences sont décelables par l’exploration des modes d’appropriation des lieux, des formes de sociabilité, des modalités de transmission et des rapports a la consommation. Celles-ci ne sont en fait que le reflet des sociétés sur-modernes, marquées par les rapports complexes entre lieux et non-lieux, entre groupe et individu, entre réel et virtuel, entre rébellion et consommation.

A total of 1873 strains from human origin and 4283 strains from non-human origin of Salmonella enterica serotypes Typhimurium, Enteritidis, Heidelberg, Hadar and Virchow, collected over three years 1993, 1997 and 2000, were examined in order to determine the rate of antimicrobial resistance to 12 antimicrobial drugs. The objective of the study was to describe and to compare the evolution of the main resistance types in human and non-human isolates, focusing on the poultry sector. The evolution and the rates of antimicrobial resistances for the five serotypes, with the exception of Virchow, were almost comparable in strains isolated from human and non-human sources over the period studied. The most striking result concerning single resistance was the spectacular increase of the resistance frequency to nalidixic acid for the strains belonging to serotypes Hadar and Virchow, especially in the poultry food sector (14% in 1993 vs. 72% in 2000 for Salmonella Virchow, 4% in 1993 vs. 70% in 2000 for Salmonella Hadar) and also in human isolates (24% in 1997 vs. 48% in 2000 for S. Virchow, 31% in 1997 vs. 78% in 2000 for S. Hadar). In addition to the classical resistance to ampicillin, streptomycin, sulphonamide, chloramphenicol and tetracycline (ASSuCT resistance type), which stabilized between 1997 and 2000, the emergence of a new resistance type was observed.

To bring evidence for or against the hypothesis of catalytic hydrogenation by intact trinuclear arene ruthenium clusters containing an oxo cap, cationic Ru3O clusters with three different arene ligands (intrinsically chiral tetrahedra) have been synthesized as racemic mixtures. By introduction of a chiral auxiliary substituent at one of the three different arene ligands, the separation of the two diastereomers was possible. The chiral Ru3O framework was evidenced by X-ray crystallography, by circular dichroism in the UV and IR regions, and by chiral shift reagents in the NMR spectra. The catalytic hydrogenation of the prochiral substrate methyl 2-acetamidoacrylate using a chiral Ru3O cluster showed no asymmetric induction, suggesting that the catalytically active species is not the intact Ru3O cluster.

Presents information on increasing violence by arsonists. Impact of school violence on the lawful aspects and the security of people; Answers brought by guarantors of calmness and social scheduling; Influence of different demonstrations of violence on school years.

The question is addressed of whether the triruthenium cluster cation [Ru3(μ2-H)3(η⁶-C6H6)(η⁶-C6Me6)2(μ3-O)]⁺, 1, is a supramolecular, outer-sphere benzene hydrogenation catalyst or is 1 a precatalyst to well-known Ru(0)n catalysis of benzene hydrogenation. This question of “is it homogeneous or heterogeneous catalysis?” is especially important in the present case since if 1 is a supramolecular, homogeneous catalyst as postulated in the literature&sbd;that is, if 1 can in fact accomplish catalysis of reactions as difficult as benzene reduction with no inner-sphere, d-orbital-mediated ligand dissociation, oxidative addition, migratory insertion, or reductive elimination&sbd;then that finding holds promise of rewriting the rules of organometallic-based catalysis. The identity of the true catalyst derived from 1 is, therefore, addressed by a collaborative effort between research groups at the Université de Neuchâtel and Colorado State University. The methodology employed is that worked out previously for addressing the historically vexing question of “is it homogeneous or heterogeneous catalysis?” (Lin, Y.; Finke, R. G. Inorg. Chem. 1994, 33, 4891). A combination of the following classes of experiments have been employed:  (i) Ru metal product studies; (ii) kinetic studies; (iii) Hg(0) and quantitative poisoning experiments, (iv) NMR studies of H/D exchange rates; (v) other data, plus (vi) the principle that the correct mechanism will explain all of the data. The results provide a compelling case that 1 is not the true benzene hydrogenation catalyst as previously believed; instead, all our evidence is consistent with, and supportive of, trace Ru(0) derived from 1 under the reaction conditions as the true, active catalyst. Nine additional conclusions are also presented as part of the summary and take-home messages, as well as a citation of “Halpern's rules” for catalysis.

The reaction of 2,3,4,7-tetrahydro-1H-inden-2-ol with ruthenium chloride hydrate in refluxing ethanol yields the chloro-bridged dinuclear complex [RuCl2(indanol)]2 (1). The mononuclear complex [Ru(indanol)(H2O)3]2+ (2), formed in situ from 1 in aqueous solution, reacts with the dinuclear complex [H3Ru2(C6Me6)2]+ to give a trinuclear arene-ruthenium cluster as a mixture of two isomers, the cations [H3Ru3(endo-indanol)(C6Me6)2(O)]+ (3a) and [H3Ru3(exo-indanol)(C6Me6)2(O)]+ (3b), in a 1:1 ratio. The hydroxy function of the indanol ligand is oriented towards the μ3-oxo cap of 3a, whereas the OH group is bent away from the metal skeleton of 3b. These two isomers, which can easily be separated by silica-gel chromatography, were isolated and characterised as their tetrafluoroborate salts. The single-crystal X-ray structure analysis of [3a][BF4] shows a strong intramolecular hydrogen bond between the μ3-oxo ligand and the hydroxyl function, which even persists in acetone solution, as demonstrated by NMR spectroscopy. On the other hand, the hydroxy function of 3b was found to be free in the solid state as well as in solution, as shown by an X-ray crystal structure analysis and by NMR spectroscopy. The catalytic activities of the water-soluble trinuclear cations 3a and 3b for the hydrogenation of benzene to give cyclohexane under biphasic conditions are considerably different, the exo isomer 3b being more active than the endo isomer 3a. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Afin de contrôler la température des ergols cryogéniques dans les réservoirs des lanceurs spatiaux, il est nécessaire de maîtriser des phénomènes thermodynamiques complexes. Pour les lanceurs du futur, l'apparition de phases à microgravité augmente cette complexité et exige des approches numériques plus complètes. Une phase caractéristique qui interviendra en microgravité dans les futurs lanceurs spatiaux est analysée ici : la dépressurisation des réservoirs cryogéniques. De par les difficultés pour réaliser des essais à grande échelle incluant une phase de microgravité avec un liquide cryogénique, on valide nos méthodes numériques par des essais au sol. Ces essais ont été réalisés sur le site de la Division des Techniques Avancées d'Air Liquide dans le cadre du programme franco-allemand COMPERE.

The structure of the phases obtained upon dehydration and decomposition of Friedel's salt [Ca2Al(OH)6]Cl·2H2O, also known as hydrocalumite, was investigated by several experimental techniques, in particular, high-temperature in situ XRD measurements, which allowed the detection of a metastable intermediate phase. Thermogravimetric analyses show that Friedel's salt, like most of the layered double hydroxides, undergoes a three-step decomposition on heating (dehydration, dehydroxylation, and anion expulsion) over the following temperature ranges: 25−280, 280−400, and >400 °C. Sharp phase transitions are observed as a result of the ordered distribution of Ca and Al atoms in the hydroxide layer and the well-ordered interlayer structure. Upon cooling to room temperature and exposure to the atmosphere, the dehydrated phase obtained by calcination between 80 and 280 °C was found to recover the basal spacing characteristic of hydrated galleries (7.81 Å) within a few minutes. The structural determination of this thermally metastable phase based on X-ray powder diffraction data recorded at 116 °C reveals a quasi-pillared layer structure with chloride anions situated midway in the interlamellar space at only 2.904(3) Å from Ca atoms of adjacent hydroxide layers. Friedel's salt becomes amorphous at ca. 400 °C, and above 750 °C, it crystallizes into a mixture of CaO and mayenite Ca12Al14O33. Exposure of the amorphous residue obtained at 400 °C to aqueous solutions of KCl led to reconstruction−intercalation phenomena.

Hydrocalumite, Ca2Al(OH)6(anion)·nH2O, belongs to the layered double-hydroxide family, with the particularity for both intralayered cations and interlayered anions and water molecules to be well-ordered. The monomer vinyl benzene sulfonate (VBS) and the syndiotactic polymer poly(styrene sulfonate) (PSS) were readily incorporated into its lamellar structure via a coprecipitation method. In situ thermal polymerization of the monomer VBS is simultaneously supported by the disappearance of the vinyl bond and the formation of −CH, −CH2 bonds. These facts are evidenced by the experiments performed by ¹³C solid-state NMR and FTIR spectroscopies. CaAl−VBS intercalate crystallizes in the C2/c space group, inducing a bilayer arrangement of VBS anions in the interlamellar space. Besides, distances between anionic sites allow an in situ zigzag polymerization of syndiotactic type along the a axis. Additionally, the contraction of the lamellar structure is found to be reversible up to 200 °C; the adjacent monomers then start to attach to each other via polymerization. The thermal stability is found to be highly dependent on the synthesis pathway. The decomposition is delayed up to 450 °C for the sample prepared via in situ polymerization while as-prepared PSS intercalate decomposes at lower temperature. Under a nitrogen atmosphere, CaS is formed at 700 °C.

The reaction of enantiopure (R)-(2-cyclohexa-1,4-dienyl)propan-1-ol with ruthenium chloride hydrate yields, without racemisation of the chiral ligand, the chloro-bridged dinuclear complex (S,S)-[RuCl2{C6H5[CH(CH3)CH2OH]}]2 (1). The dimer 1 reacts with triphenylphosphane to give the mononuclear complex (S)-[RuCl2{C6H5[CH(CH3)CH2OH]}(PPh3)] (2). A single-crystal X-ray structure analysis of 2 reveals the absolute configuration of the asymmetric carbon atom to have remained, the change from (R) to (S) being due to the priority change caused by coordination; in the solid state, onedimensional hydrogen-bonded chains are formed between the hydroxy functions and chloro ligands of neighbouring molecules. The mononuclear cationic complex (S)-[Ru{C6H5[CH(CH3)CH2OH]}(H2O)3]²⁺, formed in situ from 1 in aqueous solution, reacts with the dinuclear complex [H3Ru2(C6Me6)2]⁺ to give a chiral trinuclear arene-ruthenium cluster, the cation (S)-[H3Ru3{C6H5[CH(CH3)CH2OH]} (C6Me6)2(O)]⁺ (3). This enantiopure cation has been isolated and characterised as its tetrafluoroborate salt. The single-crystal X-ray structure analysis of (S)-[3][BF4] shows a strong intramolecular hydrogen bond between the μ3-oxo cap and the hydroxy function, which also persists in acetone solvent, as demonstrated by NMR spectroscopy. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Abstract: Fumarate reductase was used as a model oxidoreductase to demonstrate continuous electrical cofactor reduction-oxidation during the bioelectrochemical synthesis and detection of chemicals. The enzyme preparation was immobilized onto a graphite felt electrode that was modified with carboxymethylcellulose (CMC). Nicotinamide adenine dinucleotide (NAD), neutral red, and fumarate reductase (which contained menaquinone) were covalently linked by peptide bonds to the CMC. The electron mediator neutral red allowed NAD and menaquinone to be recycled electrically during enzymatic chemical synthesis. Succinate detection by the bioelectrocatalyst was linear from 5 μM to 10 mM succinate. Fumarate synthesis using this bioelectrode was dependent on succinate utilization and resulted in proportional production of electricity and fumarate. Succinate synthesis using this bioelectrocatalyst was dependent on current and fumarate concentration. This bioelectrocatalyst system may enhance the utility of menaquinone- and/or pyridine nucleotide-linked oxidoreductases in diverse enzymatic fuel cells and sensors. It may also enhance the utility of oxidoreductase-based chemical synthesis systems because it eliminates the problem of cofactor recycling.

The Thermotoga neapolitana xylose isomerase (TNXI) is extremely thermostable and optimally active at 95°C. Its derivative, TNXI Val185Thr (V185T), is the most active type II xylose isomerase reported, with a catalytic efficiency of 25.1 s–1 mM–1 toward glucose at 80°C (pH 7.0). To further optimize TNXI’s potential industrial utility, two rounds of random mutagenesis and low temperature/low pH activity screening were performed using the TNXI V185T‐encoding gene as the template. Two highly active mutants were obtained, 3A2 (V185T/L282P) and 1F1 (V185T/L282P/F186S). 1F1 was more active than 3A2, which in turn was more active than TNXI V185T at all temperatures and pH values tested. 3A2 and 1F1’s high activities at low temperatures were due to significantly lower activation energies (57 and 44 kJ/mol, respectively) than that of TNXI and V185T (87 kJ/mol). Mutation L282P introduced a kink in helix α7 of 3A2’s (α/β)8 barrel. Surprisingly, this mutation kinetically destabilized 3A2 only at pH 5.5. 1F1 displayed kinetic stability slightly above that of TNXI V185T. In 1F1, mutation F186S creates a cavity that disrupts a four‐residue network of aromatic interactions. How the conformation of the neighboring residues is affected by this cavity and how these conformational changes increase 1F1’s stability still remain unclear.

The adenylate kinase (AK) gene from Thermotoga neapolitana, a hyperthermophilic bacterium, was cloned and overexpressed in Escherichia coli, and the recombinant enzyme was biochemically characterized. The T. neapolitana AK (TNAK) sequence indicates that this enzyme belongs to the long bacterial AKs. TNAK contains the four cysteine residues that bind Zn2+ in all Gram-positive AKs and in a few other Zn2+-containing bacterial AKs. Atomic emission spectroscopy and titration data indicate a content of 1 mol of Zn2+/mol of recombinant TNAK. The EDTA-treated enzyme has a melting temperature (Tm=93.5 °C) 6.2 °C below that of the holoenzyme (99.7 °C), identifying Zn2+ as a stabilizing feature in TNAK. TNAK is a monomeric enzyme with a molecular mass of approx. 25 kDa. TNAK displays Vmax and Km values at 30 °C identical with those of the E. coli AK at 30 °C, and displays very high activity at 80 °C, with a specific activity above 8000 units/mg. The unusually high activity of TNAK at 30 °C makes it an interesting model to test the role of enzyme flexibility in activity.

We study irreducible time-homogenous Markov chains with finite state space in discrete time. We obtain results on the sensitivity of the stationary distribution and other statistical quantities with respect to perturbations of the transition matrix. We define a new closeness relation between transition matrices, and use graph-theoretic techniques, in contrast with the matrix analysis techniques previously used.