Surface Analysis of Chesapeake Bay Water Quality Response to Different Nutrient and Sediment Loads

Based on a set of Chesapeake Bay Estuarine Model (CBEM) scenarios, a three-dimensional response surface of a water quality index, such as chlorophyll concentration, versus a pair of loading constituents, e.g., nitrogen and phosphorus, is constructed. The responses of water quality, such as dissolved oxygen, chlorophyll, and water clarity, to nitrogen, phosphorus, and sediment loads are analyzed. From the response surface, a water quality response is estimated under loading conditions beyond that of a limited set of scenarios. Response surfaces may be used to determine the possible universe of nutrient and sediment load reductions needed to obtain a particular water quality standard and to examine the tradeoffs among nutrient and sediment load reductions that achieve the same water quality objective.     

Effects of age on cerebrospinal fluid oxytocin levels in free-ranging adult female and infant rhesus macaques.

There is growing interest in examining oxytocin and social functioning in human and non-human primates. Studies of human oxytocin biology are typically restricted to peripheral assessments because opportunities to collect cerebrospinal fluid (CSF) are rare. Several studies have examined CSF oxytocin levels in captive adult primates, but none to our knowledge have been conducted under free-ranging conditions and inclusive of infants. The main goal of this study was to establish feasibility of quantifying CSF oxytocin levels in free-ranging adult female and infant rhesus monkeys living on Cayo Santiago, PR. CSF oxytocin levels were examined in relation to individuals' demographic and reproductive characteristics as well as plasma cortisol levels. CSF oxytocin concentrations ranged from 36.02 to 134.41 pg/ml in adult females (ages 7–26 years; N = 31) and 35.94 to 77.3 pg/ml in infants (ages 38–134 days; N = 17). CSF oxytocin levels were positively correlated with adult female age and negatively correlated with infant age. The former correlation was driven by reproductive status. CSF oxytocin levels were unrelated to dominance rank or plasma cortisol levels. In contrast to a previous study of plasma oxytocin concentrations in this population, CSF oxytocin levels did not differ significantly between lactating and non-lactating females. These findings: 1) provide feasibility data for examining CSF oxytocin levels in free-ranging non-human primates and 2) indicate that CSF oxytocin levels may be a biomarker of age-related central nervous system changes across lifespan development. Research is now required to examine CSF oxytocin levels in the context of social functioning in free-ranging rhesus monkeys. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formation and breakdown of a protective layer of chromium sesquioxide on L-605 alloy at 1100° C

The formation and breakdown of a protective layer of Cr₂O₃ on L-605 during oxidation at 1100° C was investigated. The effects of surface deformation, pressure, and water vapor on the breakdown time were evaluated. It was found that increasing surface deformation, increased the time to breakdown. Decreasing pressure below 1 atm to 0.13 N/m² increased time of breakdown as did decreasing water content from 25,000 to 2.5 ppm. By metallographic and microprobe examinations of samples during breakdown a model was deduced. Surface deformation promotes Cr₂O₃ formation, while increasing pressure and moisture increases the volatility of Cr₂O₃. Thus, the Cr₂O₃ grows for a time determined by these three factors. At the end of this time the growth stresses cause the oxide to crack, exposing a chromium-depleted metal surface to the oxidizing gas. The resultant rapid oxidation of this surface lifts the remaining Cr₂O₃, exposing more depleted metal. When the depletion zone is consumed and a very thick oxide has formed, the rate of oxidation slows and no further disruption is noted.     

Modelling and optimization of a flexible poly(vinyl chloride) compound formulation for mine cables

Developments by Labuschagné et al. (Patent, WO 2006/123284 A2, 2006) in the manufacture of Layered Double Hydroxides (LDHs) have led to a patent describing a new effluent free synthesis method. A promising application for the LDH is as an additive for a flexible poly(vinyl chloride) (PVC) compound used for the insulation for cables used in South African underground mines. Consequently, a new formulation is required. Unfortunately formulating a PVC compound is a complex problem. The purpose of the investigation is to develop a method that can be used to find an optimum PVC formulation where the material requirements are met while also allowing for the quantitative analysis of the effect of the ingredients on the material properties. This is achieved by modeling the thermal stability, fire retardancy, and basic mechanical properties of the compound as a function of the relative proportions of the ingredients using 2nd order Scheffé polynomials. The empirical models are determined using statistical experimental design. Each model is interpreted using statistical analysis of the model terms which allows for the quantification of the effects and interactions of all the ingredients on the various response variables. The models are also used as constraints in the optimization of the PVC formulation for minimum cost. Parametric analyses are done to demonstrate how the optimization can be used to analyze the entire system taking into account the cost performance of the ingredients. Finally, it is demonstrated how the above approach requires significantly less time and labor to find an optimum formulation than the traditional approach. J. VINYL ADDIT. TECHNOL., 25:E44–E58, 2019. © 2017 Society of Plastics Engineers     

A variant human IgG1-Fc mediates improved ADCC

Ribosome display was applied to the Fc region of human immunoglobulin G (IgG1) to select for improved binding to human FcγRIIIa, the receptor expressed on human natural killer cells that mediates antibody-dependent cellular cytotoxicity (ADCC). A library of human Fcγ1 variants was generated using error-prone polymerase chain reaction, and subjected to multiple rounds of ribosome display selection against progressively decreasing concentrations of soluble human FcγRIIIa, to enrich for improved binders. Radioimmunoassay and alphascreen analyses of the aglycosylated IgG-Fc output revealed variants with improved binding to FcγRIIIa relative to wild-type IgG-Fc. Subsequent expression in human (HEK-EBNA) cells generated glycosylated IgGs with modified activity in ADCC assays. One particular variant, 125_B01 triggered enhanced ADCC (EC(50) up to four-fold reduced with increased maximal lysis) relative to wild-type antibody, having more equal levels of ADCC for each allotype (V158/F158) of FcγRIIIa. Deconvolution of individual replacements within the variant showed that improved function arose from the Phe243Leu replacement within the CH2 domain, rather than the CH3 domain replacements Thr393Ala or His433Pro. Surprisingly, the oligosaccharide profiles of 125_B01 indicated more oligosaccharide chains lacking fucose, or with bisecting N-acetylglucosamine relative to wild-type IgG1, which correlates with improved function and the replacement Phe243Leu that is a carbohydrate contact residue within the C(H)2 domain.