Conservatoire national des arts et métiers

About: Conservatoire national des arts et métiers is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Orthogonal frequency-division multiplexing. The organization has 3573 authors who have published 7127 publications receiving 141430 citations. The organization is also known as: CNAM & Conservatoire des arts et métiers.

Comparison of β-Cyclodextrin Effect on Polyphenol Oxidation Catalyzed by Purified Polyphenol Oxidase from Different Sources

Abstract: The effects of β-cyclodextrin (β-CD) on polyphenol oxidation catalyzed by apple polyphenol oxidase (PPO), endive PPO, or mushroom tyrosinase have been compared. β-CD forms a complex with phenolic substrates of PPO by inclusion. Assuming a 1:1 β-CD/phenol stoichiometry, and assuming that PPO is inactive on the complex β-CD/phenol, KD values were similar when determined kinetically by inhibition of apple PPO or endive PPO. However, the experimental velocities found during inhibition of mushroom tyrosinase by β-CD were higher than the values predicted by this model. In this latter case, it was assumed that mushroom tyrosinase is able to act on the complex β-CD/phenol. A new model based on this assumption allows experimental and calculated velocities to be fit in presence of β-CD. Keywords: Enzymatic browning; polyphenol oxidase; apple; endive; mushroom; inhibition; cyclodextrin

Oxidative stress may contribute to the intestinal dysfunction of weanling rats fed a low protein diet.

Abstract: Intestinal function is impaired in malnutrition. Because oxidative stress is a component of gastrointestinal injury, and malnutrition may reduce antioxidant defenses, we investigated the involvement of oxidative stress in the intestinal dysfunction due to malnutrition. Weanling rats were fed either a normal protein (22% casein) or a low protein (6% casein) diet for 4 wk. In intestinal homogenates, we assessed free radical damage and enzymatic antioxidant defenses. In jejunal fragments mounted in Ussing chambers, we measured ionic transport by short-circuit current (Isc) and protein permeability by transepithelial fluxes of beta-lactoglobulin. Catalase activity and the thiobarbituric acid-reacting substances concentration were greater in intestinal mucosa of the low protein group, whereas the glutathione concentration and the activities of superoxide dismutase and Se-dependent glutathione peroxidase were the same as in the normal protein group intestinal mucosa. Both basal Isc and the delta Isc induced by glucose and forskolin, as well as beta-lactoglobulin fluxes, were higher in the low protein group. Exogenous H2O2 stress increased Isc significantly more in the low protein than the normal protein group but did not alter protein permeability. These results show that malnutrition induces both intestinal free radical damage and altered epithelial transport, suggesting that oxidative stress may contribute to the intestinal dysfunction associated with malnutrition.

Comparison of liver biopsy and noninvasive techniques for liver fibrosis assessment in patients infected with HCV‐genotype 4 in Egypt

Abstract: In Egypt, as elsewhere, liver biopsy (LB) remains the gold standard to assess liver fibrosis in chronic hepatitis C (CHC) and is required to decide whether a treatment should be proposed. Many of its disadvantages have led to develop noninvasive methods to replace LB. These new methods should be evaluated in Egypt, where circulating virus genotype 4 (G4), increased body mass index and co-infection with schistosomiasis may interfere with liver fibrosis assessment. Egyptian CHC-infected patients with G4 underwent a LB, an elastometry measurement (Fibroscan(©)), and serum markers (APRI, Fib4 and Fibrotest(©)). Patients had to have a LB ≥15 mm length or ≥10 portal tracts with two pathologists blinded readings to be included in the analysis. Patients with hepatitis B virus co-infection were excluded. Three hundred and twelve patients are reported. The performance of each technique for distinguishing F0F1 vs F2F3F4 was compared. The area under receiver operating characteristic curves was 0.70, 0.76, 0.71 and 0.75 for APRI, Fib-4, Fibrotest© and Fibroscan©, respectively (no influence of schistosomiasis was noticed). An algorithm using the Fib4 for identifying patients with F2 stage or more reduced by nearly 90% the number of liver biopsies. Our results demonstrated that noninvasive techniques were feasible in Egypt, for CHC G4-infected patients. Because of its validity and its easiness to perform, we believe that Fib4 may be used to assess the F2 threshold, which decides whether treatment should be proposed or delayed.

Waveguide effects on quasispherical microwave cavity resonators

Abstract: The perturbing effect of a waveguide on the boundary of a quasispherical cavity resonator is investigated both theoretically and experimentally. Expressions for the frequency perturbation to the triply degenerate TM1mn and TE1mn modes are derived using cavity perturbation theory. The fields in and around the waveguide are calculated in the static limit using finite-element software. Experiments performed using quasispherical and cylindrical cavity resonators confirm the accuracy and generality of the approach. The impact of this study on attempts to re-determine the Boltzmann constant (kB) by an acoustic resonance technique is briefly considered.

Risk of Death Related to Psychotropic Drug Use in Older People During the European 2003 Heatwave: A Population-Based Case-Control Study

Abstract: Objective The authors investigated the association between death of older people and use of psychotropic drugs before and during the Western European August 2003 heatwave. Method A retrospective population-based case–control study was conducted using the French social security insurance national database. Exposure to psychotropic drugs in cases aged 70–100 years who died before (N = 2,093) and during (N = 9,531) the August 2003 heatwave was compared with those of survivors matched for age, gender, and presence of chronic illness, by using conditional logistic regressions. Results The association between death and psychotropic drug use was modified by level of external temperature (Wald χ 2 = 13.1, degree of freedom=1, p Conclusion Our findings suggest that a causal relationship may exist between psychotropic drug use during a heatwave and increased risk of death in older people. The risk/benefit ratio of antidepressant and antipsychotic drugs should be carefully assessed in older people during a heatwave.