Skeletal muscle protein content and synthesis after voluntary running and subsequent unweighting

The effects of exercise training with or without subsequent unweighting on wet weight, protein content, and in vivo fractional protein synthesis were studied in soleus and plantaris muscles of juvenile female Sprague-Dawley rats under the following four conditions: normal weight bearing (N), voluntary-activity wheel running (WR) for up to 4 weeks, mechanical unweighting for 7 days via hindlimb suspension (HS), or wheel running followed by 7 days of hindlimb suspension (WR-HS). Fractional protein synthesis was determined by the 3H-phenylalanine flooding method. Increases (P < .05) in wet weight and protein content were detected in the soleus after just 1 week of running, with no increase in fractional protein synthesis. Two weeks of running were required for an increase in protein synthesis in this muscle. Significant increases in these parameters were first observed in the plantaris after 2 weeks of running. Maximal increases occurred by 3 weeks in both muscles. Reductions (P < .05) in soleus and plantaris parameters were observed in both HS and WR-HS groups compared with N and WR groups, respectively. However, protein content and fractional synthesis were maintained at significantly higher levels in WR-HS muscles compared with HS muscles. These results indicate that (1) wheel training represents a noninvasive method for inducing rapid hypertrophy of the skeletal muscles studied, in part by increasing fractional protein synthesis; (2) unweighting decreases protein content and synthesis to the same extent whether the muscles are trained; and (3) previously hypertrophied muscles display higher protein contents and fractional protein synthesis following unweighting compared with unweighted muscles of untrained animals.     

Changes in CD8 cell subpopulations induced by antiretroviral therapy in human immunodeficiency virus infected patients

Although CD4+ T cells are the main target of HIV infection, CD8+ cells also play important roles in the interaction between HIV and the host immune system. The aim of this study was to analyze the effect of anti-HIV therapy on the relative proportion of some important CD8+ cell subpopulations. Five HIV-infected patients were enrolled, and blood samples were collected several times, within 90 days from the initiation of therapy. CD4+ cell count and HIV viremia were investigated, as well as the expression of CD38, HLA-DR, CD28, CD57, CD30, CD95 molecules on CD8+ cells. A complex remodeling of CD8+ cell subpopulations took place between week 2 and week 7 of treatment. This remodeling mainly consisted of: i) decrease of CD8+CD38+ and CD8+DR+ cells; ii) increase of CD8+CD28+ cells; and iii) decreased expression of the CD95/Fas molecule on CD8+ cells. Overall, these findings suggest that effective anti-HIV therapy induces changes of CD8+ subpopulations showing the reversal of the state of chronic activation that is caused by viral replication.     

Modeling and design of arrayed waveguide gratings

The purpose of this paper is twofold. First, a simple but comprehensive and powerful arrayed-waveguide grating (AWG) field model is presented which, based on Fourier optics, borrows some principles of that developed by Takeouchi and coworkers [see, Opt. Express, vol. 6, p. 124, 2000] for the analysis of reflective-type AWGs for optical signal processing, but at the same time adds more features, such as the calculation of device losses and the refinement of the mathematical model to obtain a simple expression for the output field for any input-output waveguide configuration where the meaning of the different high-level parameters of the AWG becomes very clear to the reader. Second, we elaborate on the model developed to present an useful design procedure of the AWG based on two steps illustrated by design flowcharts     

Blockade of airway inflammation and hyperresponsiveness by HIV-TAT-dominant negative Ras

We have reported previously that HIV-TAT-dominant negative (dn) Ras inhibits eosinophil adhesion to ICAM-1 after activation by IL-5 and eotaxin. In this study, we evaluated the role of Ras in Ag-induced airway inflammation and hyperresponsiveness by i.p. administration into mice of dnRas, which was fused to an HIV-TAT protein transduction domain (TAT-dnRas). Uptake of TAT-dnRas (t(1/2) = 12 h) was demonstrated in leukocytes after i.p. administration. OVA-sensitization significantly increased eosinophil and lymphocyte numbers in bronchoalveolar lavage fluid 24 h after final challenge. Treatment of animals with 3-10 mg/kg TAT-dnRas blocked the migration of eosinophils from 464 +/- 91 x 10(3)/ml to 288 +/- 79 x 10(3)/ml with 3 mg/kg of TAT-dnRas (p < 0.05), and further decreased to 116 +/- 63 x 10(3)/ml after 10 mg/kg TAT-dnRas (p < 0.01). Histological examination demonstrated that inflammatory cell infiltration (largely eosinophils and mononuclear cells) and mucin production around the airways caused by OVA were blocked by TAT-dnRas. OVA challenge also caused airway hyperresponsiveness to methacholine, which was dose dependently blocked by treatment with TAT-dnRas. TAT-dnRas also blocked Ag-induced IL-4 and IL-5, but not IFN-gamma, production in lung tissue. Intranasal administration of IL-5 caused eosinophil migration into the airway lumen, which was attenuated by pretreatment with TAT-dnRas. By contrast, TAT-green fluorescent protein or dnRas lacking the TAT protein transduction domain did not block airway inflammation, cytokine production, or airway hyperresponsiveness. We conclude that Ras mediates Th2 cytokine production, airway inflammation, and airway hyperresponsiveness in immune-sensitized mice.     

Interaction Between an Anionic and an Amphoteric Surfactant. Part I: Monomer–Micelle Equilibrium

A mixture of anionic and amphoteric surfactants is composed of three components at intermediate pH levels: anionic, cationic (protonated amphoteric), and zwitterionic (unprotonated amphoteric). Knowledge of the composition of each surfactant in both monomer and micellar forms (monomer–micelle equilibrium) is important in applications using this mixture. Hydrogen ion titration of the mixed surfactant solution as a function of surfactant composition is combined with the pseudophase separation model and regular solution theory for the three-surfactant mixture to calculate the concentration of each surfactant in monomer and in micelle forms at different pH levels. The specific systems studied here contain sodium dodecyl sulfate (SDS) and dimethyldodecylamine oxide (DDAO), which are used in a wide range of consumer products. The degree of protonation of monomeric DDAO is not affected by the presence of SDS, indicating an insignificant formation of ion pairs between these monomers. However, the presence of SDS in micelles shifts the micellar pK _a of DDAO protonation significantly and the method used here allows the quantification of partial fugacities of each individual surfactant in micelle form. The composition in the monomer phase at each pH will aid in understanding and predicting solution compositions corresponding to anionic/amphoteric surfactant precipitation boundaries, which is the focus of the subsequent paper in this series.

On the quantification of operational supply chain resilience

Operational disruptions impact a supply chain’s ability to match supply and demand. To remain competitive, supply chains need to be resilient and thus capable of rapidly and effectively recovering from operational disruptions. Supply chain resilience is inherently multidimensional, as it spans across multiple tiers, and thus is difficult to quantify. Extant research has measured the transient response through a single-dimension or single-organisation as a proxy for operational resilience. Whilst this greatly simplifies the analysis, it is also potentially misleading, as an erroneous selection of metric(s) may lead to an inaccurate evaluation of the transient response. This research extends the understanding of operational resilience via quantitative evaluation of multiple transient response measures across multiple tiers; the objective being to construct a multidimensional, multi-echelon operational supply chain resilience metric. The study utilises disruptions as experimental inputs for a serial supply chain simulation model; results are obtained for individual measurements of the transient response across multiple supply chain tiers. Analysis indicates that individual dimensions of resilience can adequately explain the transient response at the single-firm level, whilst aggregation of multiple resilience dimensions across multiple tiers has greater capacity to holistically capture the performance response to supply chain disruptions.     

Cleanliness scores as indicator of Klebsiella exposure in dairy cows

This study was designed to explore the relationship between cow and udder cleanliness scores and the risk of isolation of Klebsiella spp. from lower hind legs and teat ends, respectively. The distribution of Klebsiella species was compared among isolates from teat ends, legs, and cases of clinical mastitis obtained from 2 dairy farms in New York State, with 850 and 1,000 cows, respectively. Farms were visited twice approximately 4 wk apart in August and September 2007 to obtain cleanliness scores and swabs from legs and teats. Isolates of Klebsiella clinical mastitis from each farm were collected from July through October 2007. Two studies were conducted. In the first study, whole-cow cleanliness of a purposive sample of 200 lactating cows was scored using a 4-point scale, and swabs were taken from their lower hind legs. In the second study, udder cleanliness of a separate convenience sample of 199 lactating cows was scored in the milking parlor, and swabs were taken from their teat ends before and after premilking udder preparation. Prevalence of Klebsiella spp. on legs and teat ends before udder preparation was 59 and 60%, respectively. Logistic regression was used to explore the association between isolation of Klebsiella spp. and cleanliness scores. Cow cleanliness scores and udder cleanliness scores were not associated with detection of Klebsiella on legs and on teats before udder preparation, respectively. After udder preparation, 43% of previously Klebsiella positive teat end samples remained positive, with significant differences between farms and months. Teats from dirty udders were significantly more likely to test positive for Klebsiella after udder preparation than teats from clean udders. The proportion of Klebsiella pneumoniae and Klebsiella oxytoca isolates was similar for isolates from teat end swabs and clinical mastitis cases, supporting the notion that the presence of Klebsiella on teat ends may lead to opportunistic intramammary infections. Udder cleanliness scores could be used as a management tool to monitor the risk of exposure to Klebsiella spp. on teat ends.     

Very low surface recombination velocity of crystalline silicon passivated by phosphorus‐doped a‐SicxNy:H(n) alloys

Hydrogenated and phosphorus‐doped amorphous silicon carbonitride films (a‐SiC_xN_y:H(n)) were deposited by plasma‐enhanced chemical vapor deposition (PECVD) on crystalline silicon surface in order to explore surface passivation properties. Very silicon‐rich films yielded effective surface recombination velocities at 1 sun‐illumination as low as 3 cm s⁻¹ and 2 cm s⁻¹ on 1 Ω cm p‐ and n‐type crystalline silicon substrates, respectively. In order to use them as anti‐reflection coating, we increased alternatively either the carbon or nitrogen content of these films. Also, a combination of passivation and antireflective films was analyzed. Finally, we explored the passivation stability under high‐temperature steps. Copyright © 2007 John Wiley & Sons, Ltd.     

Contracts for recovery of investments in transmission assets

The need for investment in the improvement and expansion of the electric transmission grid has not been properly met in the new competitive environment. Investment in transmission assets poses demanding challenges: multiplicity of players, market imperfections, among others. The integration of financial instruments poses also an additional level of complication, because investors wish to ensure steady long-term returns and to withstand short-term market volatility. The integration of financial instruments poses also an additional level of complication, because investors wish to ensure steady long-term returns and to withstand short-term market volatility. This study presents a specific contract model based on financial transmission rights (FTR) for valuation of transmission assets, where the stochastic properties of all the variables related to the market structure in which the investment happens are taken into account. The model is applied to the IEEE 24-bus reliability test system showing the approach capabilities as a decision-aid tool for transmission investors.     

Dynamics of the disparity vergence step response: a model-basedanalysis

A new method to analyze the dynamics of vergence eye movements was developed based on a reconstruction of the presumed motor command signal. A model was used to construct equivalent motor command signals and transform an associated vergence transient response into an equivalent set of motor commands. This model represented only the motor components of the vergence system and consisted of signal generators representing the neural burst and tonic cells and a plant representing the ocular musculature and dynamics of the orbit. Through highly accurate simulations, dynamic vergence responses could be reduced to a set of five model parameters, each relating to a specific feature of the internal motor command. This dynamic analysis tool was applied to the analysis of inter-movement variability in vergence step responses. Model parameters obtained from a large number of response simulations showed that the width of the command pulse was tightly controlled while its amplitude, rising slope, and falling slope were less tightly regulated. Variation in the latter three parameters accounted for the most of the movement-to-movement variability seen in vergence step responses. Unlike version movements, pulse width did not increase with increased stimulus amplitude, although the other command signal parameters were substantially influenced by stimulus amplitude.