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Although not the sole feature responsible, the packing of amino acid side chains in the interior of proteins is known to contribute to protein conformational specificity. While a number of amphipathic peptide sequences with optimized hydrophobic domains has been designed to fold into a desired aggregation state, the contribution of the amino acids located on the hydrophilic side of such peptides to the final packing has not been investigated thoroughly. A set of self-aggregating 18-mer peptides designed previously to adopt a high level of α-helical conformation in benign buffer is used here to evaluate the effect of the nature of the amino acids located on the hydrophilic face on the packing of a four α-helical bundle. These peptides differ from one another by only one to four amino acid mutations on the hydrophilic face of the helix and share the same hydrophobic core. The secondary and tertiary structures in the presence or absence of denaturants were determined by circular dichroism in the far- and near-UV regions, fluorescence and nuclear magnetic resonance spectroscopy. Significant differences in folding ability, as well as chemical and thermal stabilities, were found between the peptides studied. In particular, surface salt bridges may form which would increase both the stability and extent of the tertiary structure of the peptides. The structural behavior of the peptides may be related to their ability to catalyze the decarboxylation of oxaloacetate, with peptides that have a well-defined tertiary structure acting as true catalysts. [ABSTRACT FROM AUTHOR]

Résumé Peu d’études décrivent l’incidence et l’évolution des dermo-hypodermites néonatales à streptocoque du groupe B (SGB). Objectifs Décrire l’incidence, les caractéristiques cliniques et évolutives de la dermo-hypodermite dans le cadre d’une infection à SGB chez le nourrisson de moins de 3 mois. Patients et méthodes Les nourrissons âgés de moins de 3 mois hospitalisés à l’hôpital Robert-Debré (Paris) et au centre hospitalier d’Orsay entre janvier 2002 et août 2013 pour une dermo-hypodermite à SGB ont été inclus dans une étude rétrospective. Résultats Cinq nourrissons ont été inclus. Toutes les infections étaient néonatales tardives. Le taux d’incidence parmi les infections néonatales tardives à SGB était de 7 %. Quatre patients étaient de sexe masculin et présentaient un facteur de risque d’infection maternofœtale (prématurité–hypotrophie). Quatre enfants avaient des signes cliniques spécifiques de dermo-hypodermite à l’admission associés à un tableau de choc septique. Un enfant avait une méningite et une parotidite associées. Tous avaient une hémoculture positive à SGB. Un SGB de sérotype III avait été identifié dans quatre cas. La durée de l’antibiothérapie par voie intraveineuse avait été de 7 à 23 jours et la durée totale de traitement de 14 à 44 jours. L’évolution avait été favorable dans tous les cas. Conclusion La dermo-hypodermite du nourrisson de moins de 3 mois est rare mais peut être un signe précoce d’infection invasive à SGB. Une prise en charge rapide par une antibiothérapie probabiliste, puis adaptée secondairement est indispensable. Summary Background Very few studies describe group B streptococcal dermo-hypodermitis in newborns. Objectives To describe the incidence, clinical characteristics, and course of group B streptococcal dermo-hypodermitis in infants less than 3 months old. Patients and methods Infants under 3 months of age, hospitalized for group B streptococcal dermo-hypodermitis at Robert Debré University Hospital, Paris, France, and at Orsay Hospital, Orsay, France, between January 2002 and August 2013, were included in a retrospective study. Results Five infants were included in this study. All the infections occurred late. Dermo-hypodermitis accounted for 7% of the overall late-onset group B streptococcal infections during the same period. Four patients were male and had a risk factor of maternal-fetal infection (prematurity/hypotrophy). Four patients had specific clinical signs of dermo-hypodermitis with septic shock features on admission. One patient had meningitis and associated parotitis. Group B Streptococcus was isolated from blood culture of all patients. Serotype III Streptococcus was identified in four cases. The duration of intravenous antibiotic therapy varied from 7 to 23 days and the total duration of antibiotic therapy was between 14 and 44 days. The progression was favorable for all the infants, with no recurrence. Conclusion Dermo-hypodermitis in infants under 3 months of age is rare but could be an early indicator of group B streptococcal bacteremia and/or sepsis. Early diagnosis of this severe complication and appropriate antibiotic therapy are critical. [ABSTRACT FROM AUTHOR]

Aim To evaluate (i) the diagnostic usefulness of a delayed test in initially negative patients; and (ii) the reliability of the rapid urease test, histology or a combination of the two to diagnose Helicobacter pylori during emergency endoscopy in a large clinical practice series. Patients and methods Records of patients with ulcer bleeding from 1995 to 2000 were reviewed. Patients with initially negative tests were retested 4–8 weeks after the bleeding episode. Sensitivity of urease, histology or a combination of the two to detect H. pylori at initial endoscopy and the efficacy of delayed Urea Breath Test in detecting missed infection was determined. Results The study included 429 patients. A delayed second test detected H. pylori infection in 57 out of 72 (79%) of initially negative patients. The sensitivity for detecting H. pylori was 76%, 78% and 86% for urease, histology and their combination, respectively. The prevalence of H. pylori was 95% in duodenal and 88% in gastric ulcer. In addition, only one test was performed in 17 of the 32 patients who were considered negative. Conclusion Not even the combination of a negative urease and histology in the initial endoscopy is able to rule out infection in bleeding ulcer patients. A delayed test should be performed to rule out Helicobacter pylori infection completely. [ABSTRACT FROM AUTHOR]

The solid-state synthesis and stabilization of Co doped ( Mg 1−x Co x Ti 2 O 5 ), Zn doped ( Mg 1−x Zn x Ti 2 O 5 ) and Co- and Zn-codoped karrooite solid solutions ( Mg 0.8−x Zn 0.2 Co x Ti 2 O 5 and (Mg 0.5 Zn 0.5 ) 1−x Co x Ti 2 O 5 ) were investigated. In addition, the optical spectra, color properties and technological performance of (Co,Zn)-karrooite compositions as new green ceramic pigments were also analyzed. XRD characterization revealed for the first time the high solid solubility of Zn 2+ in MgTi 2 O 5 karrooite at 1200 ºC (between 60 and 80 mol% per Mg or karrooite formula unit). In contrast, the reactivity and stabilization of karrooite phase decreased in the case of Co 2+ doping. Interestingly, codoping with Zn 2+ ions at high molar ratios (Zn:Mg ratio equal to 1:1) enhanced the reactivity and enabled the stabilization of (Co,Zn)-MgTi 2 O 5 karrooite solid solutions, even with high Co 2+ loadings (20 mol% per karrooite formula unit). The (Co,Zn)-MgTi 2 O 5 pigments exhibited yellowish-green colors associated to Co 2+ ions allocated in octahedral M1 and M2 sites of karrooite lattice, and becoming more intense and less yellow the higher the Co content. However, Zn 2+ codoping produced less saturated green colors with similar green but lower yellowish hues. The obtained pigments were not stable enough within the tested ceramic glazes, giving rise to turquoise colorations due to cobalt leaching and incorporation into tetrahedral sites of the glassy phase. The stability of Co-karrooite green pigments was higher in a Ca- and Zn-enriched ceramic glaze (B) fired at a higher temperature (1050 °C). [ABSTRACT FROM AUTHOR]

Solid solutions of Ni in MgTiO 3 ilmenite (geikielite) were investigated as potential yellowish ceramic pigments or dyes. Ni-geikielite samples (Mg 1− x Ni x TiO 3 , x = 0–0.4) were prepared by solid-state and citrate-gel routes and fired pigments were characterized by XRD, SEM/EDX, UV–vis–NIR and color measurement techniques. The increase of Ni-doping enhanced ilmenite stabilization in ceramic samples, obtaining almost single phase of Ni-geikielite for x = 0.4 at 1200 and 1400 °C. Fired pigments exhibited intense yellow colors at both temperatures, associated to Ni 2+ ions in distorted octahedral A sites of ATiO 3 ilmenite, and an increase of the orange hue with firing temperature arising from an enhanced (Mg,Ni)O 6 polyhedral distortion. Noteworthy, citrate-gel samples exhibited a much higher reactivity, yielding well-crystallized Ni-geikielite at lower temperatures (800 °C/3 h), and leading to higher chroma yellow-orange colors even at lower Ni loadings. These pigments were partially stable in commercial low-temperature ceramic glazes, giving rise to weaker yellowish colors irrespective of the preparation route. [ABSTRACT FROM AUTHOR]

In the following years power levels of 20 kW to 50 kW will be demanded by the telecommunication satellites. It is not possible to keep 0.5 kW modules with up to 100 modules in parallel and, therefore, higher power modules must be used. A higher bus voltage seems also necessary and any voltage below 150 V and above 100 V could meet the needs. In addition, new optimized topologies that process only a part of the total power delivery can be employed to improve the efficiency. In this article, design guidelines and experimental results of a high efficiency battery discharge regulator (BDR) module based on parallel power processing are given. [ABSTRACT FROM AUTHOR]

Abstract: Calmodulin is known to bind to various amphipathic helical peptide sequences, and the calmodulin–peptide binding surface has been shown to be remarkably tolerant sterically. d‐Amino acid peptides, therefore, represent potential non‐hydrolysable intracellular antagonists of calmodulin. In the present study, synthetic combinatorial libraries have been used to develop novel d‐amino acid hexapeptide antagonists to calmodulin‐regulated phosphodiesterase activity. Five hexapeptides were identified from a library containing over 52 million sequences. These peptides inhibited cell proliferation both in cell culture using normal rat kidney cells and by injection via the femoral vein following partial hepatectomy of rat liver cells. These hexapeptides showed no toxic effect on the cells. Despite their short length, the identified hexapeptides appear to adopt a partial helical conformation similar to other known calmodulin‐binding peptides, as shown by CD spectroscopy in the presence of calmodulin and NMR spectroscopy in DMSO. The present peptides are the shortest peptide calmodulin antagonists reported to date showing potential in vivo activity. [ABSTRACT FROM AUTHOR]