Nutrition support affects the distribution and organ uptake of cachectin/tumor necrosis factor in rats

BACKGROUND: We have previously observed a potentiation of the metabolic response to cachectin/tumor necrosis factor (TNF) by total parenteral nutrition (TPN) but not in anorexic orally fed animals. We hypothesized that nutritional status might affect TNF clearance kinetics. METHODS: We compared the clearance of a bolus of labeled TNF in TPN-fed animals given sufficient nutrients to grow called weight-gaining rats (WGR) with those given 50% of the WGR called weight-losing rats (WLR) and with orally fed rats (OFR). Data were analyzed using a two-compartment open system model and by linear systems analysis. RESULTS: The data from both types of analysis indicator that although metabolic clearance was similar, WGR had a slower fractional TNF clearance rate (FCR) as well as a larger volume of distribution than WLR or OFR. Further analysis showed that an increased proportion of the total mass of TNF resided in a plasma-associated compartment in WGR compared with WLR and OFR. In addition, WGR had reduced uptake of labeled TNF by the kidney. CONCLUSION: The data suggest that nutrition support influences either the distribution of TNF or the FCR, resulting in a greater retention in the plasma-associated compartment with intact absolute removal rates. This study has important implications concerning the type of nutrition support provided to the critically ill patient because our data suggest that clinical states with increased circulating TNF levels may be adversely affected by currently available nutritional practices.     

Self-efficacy and mathematics achievement: A study of their relation.

In this study, I investigated the relation between self-efficacy and mathematics achievement when other factors, such as self-concept of math ability, prior task achievement, and prior self-efficacy were taken into account. I assessed self-efficacy over 4 trials in a repeated-measures design with 72 children, aged 9–10 years. I assessed task performance after the first and third self-efficacy assessment. Regression analysis indicated small or no predictive relation between self-efficacy and task performance, depending on task familiarity, when these other factors were included in the analysis. Results of the study lend one to doubt that there is a simple relation between self-efficacy and task performance in the field of mathematics learning. The complexity of self-efficacy, its sources, and consequences are also illustrated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antigen activation rescues recent thymic emigrants from programmed cell death in the BB rat

One of the diabetes susceptibility genes of the BB rat is a mutation at the lyp locus that decreases the thymic output of T cells and the life span of most recent thymic emigrants (RTE). Consequently, there is a 10-fold reduction in the number of CD4+ and CD8+ T cells in secondary lymphoid organs. Results presented in this work demonstrate that the BB rat lyp mutation is associated with an accelerated apoptotic death in vitro of mature CD4+ 8- and CD4- 8+ thymocytes and peripheral T cells. The stability of the pool of recirculating T cells (PRL) of BB rats over time results from a > 10-fold increase in the mitotic activity of T cells as assessed in vivo by bromodeoxyuridine incorporation. This increased mitotic activity is not observed when BB T cells develop in the context of a normal sized PRL. MHC haploidentical WF and BB rats differ at minor histocompatibility loci. Intravenous injection of (WF x BB)F1 T cells into euthymic BB rats led to the rejection of donor T cells within 3 wk by unprimed recipients and within 1 wk by primed recipients. This secondary immune response was unaffected by postpriming thymectomy. F1 T cells were not rejected, but rather expanded after their injection into thymectomized BB rats that had been primed as early as 48 h after thymectomy. These results strongly suggest that the BB rat PRL is devoid of long-lived naive T cells and that rescue of recent thymic emigrants from programmed cell death is initiated by Ags, exclusively.     

A Study of the Properties of a Room Temperature Martensitic Binary Nitinol Alloy Above and Below its Martensite to Austenite Transformation Temperature

Room temperature martensitic Nitinol alloys provide a challenge to end users of the material because they are martensitic and soft at room temperature. These are commonly referred to as Shape Memory alloys as they revert to their superelastic (pseudoelastic) form and austenitic structure at a temperature above ambient. For this study, a NiTi wire, Ti-55.3 wt.%Ni in composition (Alloy-B) and heat-treated to an Af ?? 60 °C was used. Tensile testing was performed to fully characterize the performance of the material at a series of temperatures above and below its transformation temperature. This article will summarize the properties of the material along with the effects of multiple strains on key material performance characteristics.     

A Study of the Effect of Diameter on the Fatigue Properties of NiTi Wire

It is a generally held belief that controlled strain fatigue life is independent of wire diameter. This has led to the widespread use of general S-N or ε-N curves for engineering metals. Independence of wire diameter on fatigue life may not hold true for Nitinol. If so, care must be used when applying generic Nitinol S-N or ε-N curves to product design. To provide a more comprehensive understanding of this issue, a comparison study was conducted on the fatigue properties of various diameters of NiTi (Ti-55.8/55.9wt.%Ni) wire drawn from the same starting material. ε-N curves were generated for various diameters. The wire diameter reduction from 0.030′′ to 0.010′′ increased the 0.8% strain 80k cycle survival rate from 35 to 96%. For the scope of this study, all factors that may have an effect on fatigue life except for wire diameter were held constant.     

Corrosion Behavior of Ti-55Ni-1.2Co High Stiffness Shape Memory Alloys

The corrosion behavior of high stiffness nominal Ti-55Ni-1.2Co (wt.%) shape memory alloys (SMAs) was systematically investigated in the present study including straight wires, wire-formed stents, and laser-cut stents. It was found that the corrosion behavior of Ti-55Ni-1.2Co alloys is comparable with those of binary NiTiNol counterparts, which is attributed to the small alloying amount of cobalt. Additionally, the corrosion resistance of high stiffness Ti-55Ni-1.2Co SMAs is independent of the stent-forming method. To explore the galvanic corrosion susceptibility between Ti-55Ni-1.2Co and binary NiTiNol alloys, a NiTiNol sleeve was laser welded to the Ti-55Ni-1.2Co stent. Interestingly, there is no galvanic corrosion observed in this NiTiCo-NiTiNol component, even after immersion of the component in phosphate-buffered saline solution at 37 °C for three months. This study will shed some light on the industrial applications of high stiffness Ti-55Ni-1.2Co shape memory alloys.     

The contribution of special education to our understanding of values, schooling and the curriculum

This article presents an analysis of how special education contributes to our contemporary understanding of educational values, schooling and the curriculum. We argue that special education is not simply and only a separate part of education, it is inherently connected to all aspects of education. This connective position is contrasted with the recurrent view that the full range of educational needs can be separated out neatly into the majority with 'normal' needs and the minority with 'special needs'. There are indications that the New Labour government is engaging in this oversimplified distinction in its educational policy. The article focuses on two key changes in the education service over the past decade from a special educational needs perspective: the introduction of the National curriculum and the policy move towards greater school specialisation. It argues for a multi-dimensional concept of educational needs as the basis for connecting special and mainstream education. The contribution of special education to our wider understanding of education is presented in terms of three key areas: the nature of values in education, the impact of market choice and the stress on achievement as a leading value.     

Differentiation: from the perspective of resolving tensions between basic social values and assumptions about individual differences

Differentiation has become a topical matter in the wake of the implementation of the National Curriculum. This paper explores different conceptions and evaluations about differentiation. One of its main aims is to show that the issue of differentiation arises out of the tension between the basic values of equality and belongingness on one hand and individuality on the other. This is reflected in the processes of teaching and learning, in the design of the curriculum and the organisation of schooling, and in the Intended outcomes of learning. Another aim is to show the links between these value considerations and particular assumptions about the nature and sources of individual differences. The case for a genuine interactionist model is presented which recognises the interplay between internal child and external environmental factors. This model is associated with the position that there is a plurality of values which need to be balanced and reconciled.     

Identification variability as a measure of loudness: An application to gender differences.

It is well known that discrimination response variability increases with stimulus intensity, closely related to Weber's Law. It is also an axiom that sensation magnitude increases with stimulus intensity. Following earlier researchers such as Thurstone, Garner, and Durlach and Braida, we explored a new method of exploiting these relationships to estimate the power function exponent relating sound pressure level to loudness, using the accuracy with which listeners could identify the intensity of pure tones. The log standard deviation of the normally distributed identification errors increases linearly with stimulus range in decibels, and the slope, a, of the regression is proportional to the loudness exponent, n. Interestingly, in a demonstration experiment, the loudness exponent estimated in this way is greater for females than for males. (PsycINFO Database Record (c) 2010 APA, all rights reserved)