Nickel adsorption by magnetic alginate microcapsules containing an extractant

The adsorption of heavy metals on biomaterials was investigated by studying the potential of alginate microcapsules containing an extractant (Cyanex 272) and magnetic nanoparticles (gamma-Fe2O3) for the adsorption of nickel (II) from aqueous solutions. A two-stage kinetics behaviour was observed with 70% of the maximum sorption capacity achieved within 8 h. An increase in nickel removal with increase in pH occurred, the maximum uptake capacity being around 0.42 mmol g-1 at pH 8. The adsorption isotherm (pH about 5.3) was obtained in a wide range of initial nickel concentrations; the experimental data were fitted by a Langmuir model and the qmax value was estimated to be 0.52 mmol g-1. Moreover, including magnetic particles in the microcapsules allowed easy isolation of the beads from the aqueous solutions after the sorption process. Magnetic microcapsules are then suitable for the development of efficient biosorbents for removal and recovery of heavy metals from wastewater using magnetic separation.     

Influence of Suspension Plasma Spraying Process Parameters on TiO2 Coatings Microstructure

The study aimed at optimizing the suspension plasma spraying of TiO₂ coatings obtained using different suspensions of fine rutile particles in water solution onto aluminum substrates. The experiments of spraying were designed using a 2³ full factorial plan. The plan enabled to find the effects of three principal parameters, i.e. electric power input to plasma, spray distance, and suspension feed rate onto microstructure of coatings, content of anatase phase and size of anatase crystals in the coatings. The microstructure of deposits was observed with scanning electron microscope (SEM) and optical microscope and their composition was characterized using energy dispersive spectrometry (EDS). The observations were made on the coatings surface and their cross-sections. The latter made it possible to determine the coatings thicknesses to be in the range from 8 to 33 μm.

Comparison of the effects of a 24-hour nicotine patch and a 16-hour nicotine patch on smoking urges and sleep.

This randomized, open-label, crossover study was conducted to compare the effects of a 24-hr nicotine patch and a 16-hr nicotine patch on morning smoking urges and sleep quality of dependent smokers during a short period of cigarette abstinence. A total of 20 smokers (9 women and 11 men) smoking at least 20 cigarettes/day completed the two smoke-free study periods. For each period, cigarette abstinence started on the first evening and a nicotine patch was applied the next morning (for 16 or 24 hr), after baseline measures; a second patch was applied the next morning, 1 hr before the end of the experimental period. Smoking urges, mood and behavior self-reports, psychomotor performance, and polysomnographic recordings were compared between the two types of nicotine patch according to changes from baseline. Both patches decreased morning smoking urges, although results were significantly superior for the 24-hr patch. Furthermore, the 24-hr patch was more effective than the 16-hr patch in reducing the positive reinforcing dimension of smoking urges. Regarding polysomnographic recordings, the proportion of slow wave sleep was significantly increased from baseline with the 24-hr patch compared with the 16-hr patch. As for psychomotor performance measured through the critical flicker fusion test, significant improvement in morning alertness was observed in the 24-hr patch group. In conclusion, the 24-hr nicotine patch formulation is more effective than the 16-hr formulation in alleviating morning smoking urges and more specifically the positive reinforcing factor. The present findings do not support the idea that nicotine delivery during bedtime might disturb sleep, but rather it improves restorative sleep and postwaking arousal.     

Isolation and characterization of anti-FcgammaRIII (CD16) llama single-domain antibodies that activate natural killer cells

FcgammaRIII (CD16) plays an important role in the anti-tumor effects of therapeutic antibodies. Bi-specific antibodies (bsAbs) targeting FcgammaRIII represent a powerful alternative to the recruitment of the receptor via the Fc fragment, but are not efficiently produced. Single-domain antibodies (sdAbs) endowed with many valuable structural features might help to bypass this problem. In the present work, we have isolated anti-FcgammaRIII sdAbs (C21 and C28) from a phage library generated from a llama immunized with FcgammaRIIIB extra-cellular domains. These sdAbs bind FcgammaRIIIA+ NK cells and FcgammaRIIIB+ polymorphonuclear cells, but not FcgammaRI+ or FcgammaRII+ cells, as detected by indirect immunofluorescence. Competition experiments showed that C21 and C28 sdAbs bind different FcgammaRIII epitopes, with C21 recognizing a linear and C28 a conformational epitope of the receptor. Surface plasmon resonance experiments showed that C21 and C28 sdAbs bind FcgammaRIII with a K(D) in the 10 and 80 nM range, respectively. Importantly, the engagement by both molecules of FcgammaRIIIA expressed by transfected Jurkat T cells or by NK cells derived from peripheral blood induced a strong IL-2 and IFN-gamma production, respectively. These anti-FcgammaRIII sdAbs represent versatile tools for generating bsAbs under various formats, able to recruit FcgammaRIII killer cells to target and destroy tumor cells.     

Home and leisure injuries among the French electricity and gas company active employees: circumstances and short-term consequences

OBJECTIVE: To characterize home and leisure injuries and their immediate consequences among adults aged 20-60 years and to look for homogeneous profiles of injury circumstances to assess the possibility of setting up prevention programs. DESIGN: Cross-sectional survey by questionnaire completed on the occasion of a medical visit after a first episode of absence for home or leisure injury between 1 January and 31 December 1997 among Electricité de France Gaz de France (EDF GDF) workforce of three geographical areas (47,681 employees). Incidence and relative risks according to sex, age and work grade and a multidimensional classification of injury circumstances. RESULTS: Eight hundred and fifty four injuries were studied. Risk was estimated at 18.4 injury victims per 1000 employees, of which 13.4 per 1000 employees were home injury victims and 3.7 leisure injury victims. The risk of all injuries was higher among men than women (RR=1.3) and decreased as work grade rose: for men, it was five times higher among operating employees than managers. Multidimensional analysis of injury circumstances ended by distributing into four main classes which may be useful for prevention: gardening and do-it-yourself injuries outdoors (19.9%), coming and going on the streets (6.9%), falling while coming and going in the home on the stairs (13.4%), and do-it-yourself inside the home (13.0%). Injuries induced essentially four types of lesions: sprains (34%), fractures (31.8%), contusions (24.5%) and wounds. The mean sick-leave lasted 32.1 days but half the subjects returned to work in less than 17 days. Hospitalization was necessary in 19.2% of cases. CONCLUSIONS: This study completed by an analysis of the behavioural factors of injuries led us to propose programs aimed at changing the risk behaviours related to do-it-yourself, stairs falls and gardening.     

GENOTOXIC ACTIVITY OF THIOPHENES ON LIVER HUMAN CELL LINE (HepG2)

Thiophenes, a class of polycyclic aromatic compound (PAC), which contain a sulfur in one of the rings, are components of petroleum. The Erika oil spill (December 1999) impacted 400 km of Atlantic French coast. The Erika fuel is an heavy fuel containing 3–4% sulfur and sulfur compounds such as thiophenes. It has been reported that water and sediments were contaminated by dibenzothiophene (DBT). Analysis of DNA adducts in fish liver and mussel digestive gland, living in sites impacted by Erika oil spill, has revealed DNA adduct pattern different from a classical PAH contamination. Few studies report biological activities of thiophenes in the environment (1 Kropp, K. G. and Fedorak, P. M. 1998. A Review of the Occurrence, Toxicity, and Biodegradation of Condensed Thiophenes Found in Petroleum. Canadian Journal of Microbiology, 44: 605–622. [Crossref], [Web of Science ®] , [Google Scholar]). In this study, we have analyzed the cytotoxicity and the genotoxicity of six thiophenes [benzo(b)]thiophene (BT), dibenzothiophene (DBT), benzo(b)naphtha(2,1-d)thiophene (BNT), 6-methylbenzo(b)naphtha(2,1-d)thiophene (6-CH₃BNT), dinaptho(2,1-b;1′,2′-d)thiophene (DNT), and diphenanthro(9,10-b;9′,10′-d)thiophene (DPT) in liver human cell line (HepG2). Whatever the doses, BT, DPT, and DNT do not form DNA adducts in HepG2 cell line. On the contrary, DBT, BNT, and 6-CH₃ BNT induced DNA adduct formation. Two individual adducts are formed with DBT and one with BNT. The 6-CH₃BNT which is the alkylated homologue of BNT also forms two adducts which are persistent after 48 h of treatment. Our results show that some thiophenes are genotoxic for HepG2 cells.     

Evolution of interleukin-15 for higher E. coli expression and solubility

Directed evolution was used to generate IL-15 mutants with increased solubility and cytoplasmic over-expression in Escherichia coli. A protein solubility selection method was used in which the IL-15 gene was expressed as an N-terminal fusion to chloramphenicol acetyltransferase (CAT) as reporter protein. Clones that grew in the presence of high concentrations of chloramphenicol were then screened by ELISA to assay the binding activity of the IL-15-CAT fusion to the IL-15Rα Sushi domain. Two variants of IL-15, M38 and M253, containing five mutations and one mutation respectively, were selected with a dramatic improvement in solubility; the soluble concentration in cell culture was 12- to 18-fold higher, respectively, than for WT IL-15. Characterization of their binding to IL-15Rα and their ability to stimulate the T-cell growth response showed that M38 binds as strongly as native IL-15 to IL-15Rα and acts as an effective agonist of IL-15.     

Re-designed N-terminus enhances expression, solubility and crystallizability of mitochondrial protein

Mitochondrial aminoacyl-tRNA synthetases are key enzymes in translation. They are encoded by the nuclear genome, synthesized as precursors in the cytosol and imported. Most are matured by cleavage of their N-terminal targeting sequence. The poor expression of mature proteins in prokaryotic systems, along with their low solubility and stability after purification are major obstacles for biophysical and crystallographic studies. The purpose of the present work was to analyze the influence of additives on a slightly soluble aspartyl-tRNA synthetase and of the N-terminal sequence of the protein on its expression and solubility. On the one hand, the solubility of the enzyme was augmented to some extent in the presence of a chemical analog of the intermediary product aspartyl-adenylate, 5'-O-[N-(L aspartyl) sulfamoyl] adenosine. On the other hand, expression was enhanced by extending the N-terminus by seven natural amino acids from the predicted targeting sequence. The re-designed enzyme was active, monodisperse, more soluble and yielded crystals that are suitable for structure determination. This result underlines the importance of the N-terminal residue sequence for solubility. It suggests that additional criteria should be taken into account for the prediction of cleavage sites in mitochondrial targeting sequences.     

Exfoliated polymer nanocomposites by in situ coprecipitation of layered double hydroxides in a polymer matrix

Polyvinylalcohol (PVA) nanocomposites were prepared by a “one step” method based on the coprecipitation of layered double hydroxide (LDH) platelets in the polymer aqueous solution. The PVA/LDH nanocomposites displayed an exfoliated morphology and the concentration of LDH in the nanocomposite was evaluated by IR analysis. Moreover, it was shown that the PVA/LDH nanocomposites had an improved photostability over PVA, which makes this material a good candidate for coating applications. Further optimization will be considered to tune the polymer/LDH properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mapping of a serine-rich domain essential for the transcriptional, antiapoptotic, and transforming activities of the v-Rel oncoprotein

Patients with adult GH deficiency are often dyslipidemic and may have an increased risk of cardiovascular disease. The secretion and clearance of very low density lipoprotein apolipoprotein B 100 (VLDL apoB) are important determinants of plasma lipid concentrations. This study examined the effect of GH replacement therapy on VLDL apoB metabolism using a stable isotope turnover technique. VLDL apoB kinetics were determined in 14 adult patients with GH deficiency before and after 3 months GH or placebo treatment in a randomized double blind, placebo-controlled study using a primed constant [1-(13)C]leucine infusion. VLDL apoB enrichment was determined by gas chromatography-mass spectrometry. GH replacement therapy increased plasma insulin-like growth factor I concentrations 2.9 +/- 0.5-fold (P < 0.001), fasting insulin concentrations 1.8 +/- 0.6-fold (P < 0.04), and hemoglobin A1C from 5.0 +/- 0.2% to 5.3 +/- 0.2% (mean +/- SEM; P < 0.001). It decreased fat mass by 3.4 +/- 1.3 kg (P < 0.05) and increased lean body mass by 3.5 +/- 0.8 kg (P < 0.01). The total cholesterol concentration (P < 0.02), the low density lipoprotein cholesterol concentration (P < 0.02), and the VLDL cholesterol/VLDL apoB ratio (P < 0.005) decreased. GH therapy did not significantly change the VLDL apoB pool size, but increased the VLDL apoB secretion rate from 9.2 +/- 2.0 to 25.9 +/- 10.3 mg/kg x day (P < 0.01) and the MCR from 11.5 +/- 2.7 to 20.3 +/- 3.2 mL/min (P < 0.03). No significant changes were observed in the placebo group. This study suggests that GH replacement therapy improves lipid profile by increasing the removal of VLDL apoB. Although GH therapy stimulates VLDL apoB secretion, this is offset by the increase in the VLDL apoB clearance rate, which we postulate is due to its effects in up-regulating low density lipoprotein receptors and modifying VLDL composition.