Experimental investigation of the gain flatness characteristics for1.55 μm erbium-doped fluoride fiber amplifiers

The flat gain over a broad spectral width offered by fluoride-based Erbium-Doped Fiber Amplifiers (EDFA) appears very attractive for wavelength-multiplex systems operating near 1550 nm. The relevant parameters (input pump and signal powers, fiber length) that determine the gain flatness characteristics of fluoride-based EDFA have been experimentally investigated. It is found that hat gain operation requires an optimal, though not critical, population inversion within the doped fiber, which is somewhat lower than the maximum population inversion achievable with 1.48 μm-pumping. Implications on the design and operating conditions of fluoride-based EDFA are discussed     

Impact of pump OSNR on noise figure for fiber-optical parametric amplifiers

Electrical measurements of the noise figure of a fiber-optical parametric amplifier are presented and compared with optical measurements. The transfer of pump noise by four-wave mixing was clearly demonstrated. A numerical model was developed to simulate the transfer of pump noise and validated by these measurements. Using this model, we determine, for practical systems, a minimum required pump optical signal-to-noise ratio of 65 dB.     

The possibility of intercalating alkali metals in a glass of the system V2O5 - P2O5

A semi-conducting phosphovanadate glass was tested as a possible material for positive electrode in solid state batteries.O.c. voltage with alkali metal (3.6 V/Li and 3.4 V/Na) is higher than for crystallized vanadium oxides and chemical intercalation of sodium or lithium is obtained using halogenated salts dissolved in organic solvents.     

Protein Engineering Strategies for Improved Pharmacokinetics

Protein therapeutics have gained momentum in recent years and become a pillar in treating many diseases and the only choice in several ailments. Protein therapeutics are highly specific, tunable, and less toxic than conventional small drug molecules. However, reaping the full benefits of therapeutic proteins in the clinics is often hindered by issues of immunogenicity and short half-life due essentially to fast renal clearance and enzymatic degradation. Advances in polymer chemistry and protein engineering allowed overcoming some of these limitations. Strategies to prolong the half-life of proteins rely on increasing their size and stability and/or fusing them to endogenous proteins (albumin, Fc fragment of antibody) to hijack physiological pathways involved in protein recycling. On the downside, these modifications might alter therapeutic proteins structure and function. Therefore, a compromise between half-life and activity is sought. This review covers half-life extension strategies using natural and synthetic polymers as well as fusion to other proteins and sheds light on genetic engineering strategies and chemical and enzymatic reactions to achieve this goal. Promising strategies and successful applications in the clinics are highlighted.     

Reasoning Mechanism for Construction Nonconformance Root-Cause Analysis

This paper describes how problem patterns can be identified and analyzed for diagnosing and/or predicting nonconformance of constructed facilities. This will enable appropriate actions to be taken for eradicating the causes of nonconformance and preventing their recurrence and/or their occurrence. A structure has been defined for representing construction projects information and organizing knowledge extracted from past experience to facilitate the analyses. Pattern analyses have been directed at deriving root cause classes of problems including (1) design, which relates to the assigned specifications, methods, and/or procedures; (2) execution, which involves errors or the inability to execute tasks; and (3) external, which includes unforeseen events or accidents. Highway pavement construction has been selected as an application and illustrative domain. Expert knowledge related to low density and roughness of constructed pavements has been assembled and organized to support the analyses. The approach provides a generic mechanism to carry out integrated root cause analyses with design/planning, construction, and quality management information. Its application has been demonstrated and validated using case studies from different construction domains.     

Physicochemical characteristics and bronchial epithelial cell cytotoxicity of Folpan 80 WG® and Myco 500®, two commercial forms of folpet

Background

Pesticides, in particular folpet, have been found in rural and urban air in France in the past few years. Folpet is a contact fungicide and has been widely used for the past 50 years in vineyards in France. Slightly water-soluble and mostly present as particles in the environment, it has been measured at average concentration of 40.1 μg/m³ during its spraying, 0.16–1.2 μg/m³ in rural air and around 0.01 μg/m³ in urban air, potentially exposing both the workers and the general population. However, no study on its penetration by inhalation and on its respiratory toxicity has been published. The objective of this study was to determine the physicochemical characteristics of folpet particles (morphology, granulometry, stability) in its commercial forms under their typical application conditions. Moreover, the cytotoxic effect of these particles and the generation of reactive oxygen species were assessed in vitro on respiratory cells.

Results

Granulometry of two commercial forms of folpet (Folpan 80WG^® and Myco 500^®) under their typical application conditions showed that the majority of the particles (>75%) had a size under 5 μm, and therefore could be inhaled by humans. These particles were relatively stable over time: more than 75% of folpet remained in the particle suspension after 30 days under the typical application conditions. The inhibitory concentration (IC₅₀) on human bronchial epithelial cells (16HBE14o-) was found to be between 2.89 and 5.11 μg/cm² for folpet commercial products after 24 h of exposure. Folpet degradation products and vehicles of Folpan 80 WG^® did not show any cytotoxicity at tested concentrations. At non-cytotoxic and subtoxic concentrations, Folpan 80 WG^® was found to increase DCFH-DA fluorescence.

Conclusion

These results show that the particles of commercial forms of folpet are relatively stable over time. Particles could be easily inhaled by humans, could reach the conducting airways and are cytotoxic to respiratory cells in vitro. Folpet particles may mediate its toxicity directly or indirectly through ROS-mediated alterations. These data constitute the first step towards the risk assessment of folpet particles by inhalation for human health. This work confirms the need for further studies on the effect of environmental pesticides on the respiratory system.     

Impact psychologique de l'horaire de travail et de la participation aux taches familiales chez des couples à double carrière.

The present research examined the joint impact of characteristics of the work schedule and the participation in household work on psychological distress and parental role strain as well as stress crossover. A total of 93 dual-earner couples with at least one child living at home participated. Multiple regression analyses revealed that predictive variables of the psychological distress or the parental role strain differed for men and women and that the parental role strain was related to the psychological distress for both men and women. Results partially support the hypothesis of stress crossover since no characteristics of work schedule of the husband's and wife's were related to parental role strain of the spouses, but women's participation in the children's care was associated with men's higher parental role strain. These results underline the importance of studying strains associated with specific social roles of women and men with respect to effects of both work schedule and family strains related to psychological distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Study of a 231 French Patient Cohort Significantly Extends the Mutational Spectrum of the Two Major Usher Genes MYO7A and USH2A

Usher syndrome is an autosomal recessive disorder characterized by congenital hearing loss combined with retinitis pigmentosa, and in some cases, vestibular areflexia. Three clinical subtypes are distinguished, and MYO7A and USH2A represent the two major causal genes involved in Usher type I, the most severe form, and type II, the most frequent form, respectively. Massively parallel sequencing was performed on a cohort of patients in the context of a molecular diagnosis to confirm clinical suspicion of Usher syndrome. We report here 231 pathogenic MYO7A and USH2A genotypes identified in 73 Usher type I and 158 Usher type II patients. Furthermore, we present the ACMG classification of the variants, which comprise all types. Among them, 68 have not been previously reported in the literature, including 12 missense and 16 splice variants. We also report a new deep intronic variant in USH2A. Despite the important number of molecular studies published on these two genes, we show that during the course of routine genetic diagnosis, undescribed variants continue to be identified at a high rate. This is particularly pertinent in the current era, where therapeutic strategies based on DNA or RNA technologies are being developed.     

Laser damage resistance of hafnia thin films deposited by electron beam deposition, reactive low voltage ion plating, and dual ion beam sputtering

A comparative study is made of the laser damage resistance of hafnia coatings deposited on fused silica substrates with different technologies: electron beam deposition (from Hf or HfO(2) starting material), reactive low voltage ion plating, and dual ion beam sputtering. The laser damage thresholds of these coatings are determined at 1064 and 355 nm using a nanosecond pulsed YAG laser and a one-on-one test procedure. The results are associated with a complete characterization of the samples: refractive index n measured by spectrophotometry, extinction coefficient k measured by photothermal deflection, and roughness measured by atomic force microscopy.     

Sensory and physicochemical evolution of tropical cooked peeled shrimp inoculated by Brochothrix thermosphacta and Lactococcus piscium CNCM I-4031 during storage at 8°C

This study investigated the sensory quality and physicochemical evolution (pH, glucose, l-lactic acid, biogenic amine, free amino-acids and volatile compounds) during storage at 8 °C of cooked peeled shrimp inoculated with the specific spoilage bacteria Brochothrix thermosphacta alone or mixed with the protective strain Lactococcus piscium CNCM I-4031. Growth of both bacteria was monitored at regular intervals during storage by microbial counts and the thermal temperature gradient gel electrophoresis (TTGE) technique. Bacterial counts showed that L. piscium and B. thermosphacta inoculated at 7 log CFU/g and 3 log CFU/g were well adapted to shrimp, reaching a maximum level of 9 log CFU/g after 4 days and 10 days respectively. In mixed culture, the growth of B. thermosphacta was reduced by 3.2 ± 0.1 log CFU/g. The TTGE technique allowed monitoring the colonisation of the strains on the shrimp matrix and confirming the dominance of L. piscium in mixed culture throughout the experiment. Sensory analysis confirmed that B. thermosphacta spoiled the product after 11 days, when its cell number attained 8 log CFU/g with the emission of strong butter/caramel off-odours. This sensory profile could be linked to the production of 2,3 butanedione, cyclopentanol, 3-methylbutanol, 3-methylbutanal, 2-methylbutanal, 4-methyl-3-chloro-3-pentanol and ethanol, which were produced in more significant quantities in the B. thermosphacta batch than in the batches in which the protective strain was present. On the contrary, TVBN and TMA were not suitable as quality indicators for B. thermosphacta spoilage activity. In the products where the protective L. piscium strain was present, no adverse effect on sensory quality was noted by the sensory panels. Moreover, biogenic amine assessment did not show any histamine or tyramine production by this strain, underlining its safety profile. Both strains produced lactic acid (1850 mg/kg in L. piscium and B. thermosphacta batch on days 3 and 10 respectively; 3830 mg/kg on day 7 in mixed culture) and the pH decrease from 6.6 ± 0.0 to 5.9 ± 0.1 was similar in all batches. Lactic acid production or competition for free amino-acid was not involved in the inhibition mechanism; however rapid glucose consumption by L. piscium could partially explain the growth limitation of the spoilage micro-organism. This study demonstrated the spoilage characteristic of B. thermosphacta and the usefulness of L. piscium as a bioprotective culture for tropical cooked peeled shrimp without any adverse effect on the sensory quality of the product.