1,977 research outputs found

    Myelin basic protein peptide 45–89 induces the release of nitric oxide from microglial cells.

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    Continuous (24 h) exposure of mixed oligodendrocyte/microglial cells to peptides 45–89 derived from citrullinated C8 isoforms of myelin basic protein (MBP) induces cell death. In contrast, MBP-C8 at the same molecular concentration is not toxic to oligodendrocyte/microglial cells as detected by the MTT test and trypan blue exclusion method. The loss of oligodendrocyte/microglial cells resulted in the release of cytochrome c from mitochondria, suggesting MBP 45–89-induced apoptosis. On the other hand, peptides 45–89 stimulated the secretion of nitric oxide from microglial cells only via induction of iNOS. The addition of peptide 45–89 to the microglial cells led to a decrease of the level of the inhibitory protein IkB, indicating that activation of the transcription factor NF-kB is involved in these processes. We propose that the immunodominant peptide 45–89 induces damage of oligodendrocytes by activation of microglial cells and subsequent generation of nitric oxide, and that this may be the first step in the initiation of autoimmunity

    Evaluating Retention Strategies for At-Risk Undergraduate Nursing Students

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    As there continues to be a nursing shortage and a lack of diversity in the nursing profession, it is important to retain at-risk students who have been admitted to nursing programs. The purpose of this program evaluation was to compare at-risk students who had not received retention services to at-risk students who had received retention services at a Midwestern college. A formative evaluation was conducted using information from three sources: the college, the students, and the community. Guided by a constructivist theory defined by Ponticell, this study examined the effectiveness of the retention program in terms of its impact on course completion rates, semester, and cumulative GPAs, and number of students on probation and dismissed from the college. Using a retrospective quasi-experimental design, data from 72 students in 2 groups were compared using chi-square, t tests, and one-way repeated-measures ANOVA. Although the results were not significant, students who received retention services were less frequently on probation and dismissed, had higher course completion rates, and had higher GPAs. In addition, 54 graduating students were surveyed, and their perceptions of the retention services were positive, with an overall mean score of 4.02 out of 5.0. Themes identified through a community key informant interview included student/personal responsibility, family responsibility, and community responsibility. The program evaluation was summarized in an evaluation report that included the results and recommendations for continuation or the addition of retention services. This study may impact social change as the retention services are reviewed and adjusted in order to produce an increased number of qualified, diverse registered nurses

    Sensitive imaging of electromagnetic fields with paramagnetic polar molecules

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    We propose a method for sensitive parallel detection of low-frequency electromagnetic fields based on the fine structure interactions in paramagnetic polar molecules. Compared to the recently implemented scheme employing ultracold 87^{87}Rb atoms [B{\"o}hi \textit{et al.}, Appl. Phys. Lett. \textbf{97}, 051101 (2010)], the technique based on molecules offers a 100-fold higher sensitivity, the possibility to measure both the electric and magnetic field components, and a probe of a wide range of frequencies from the dc limit to the THz regime

    A novel concept for the manufacture of individual sapphire-metallic hip joint endoprostheses.

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    At the present time, artificial joints made with metallic, ceramic, metal-polymeric or ceramicpolymeric friction pairs substituting for the natural biomechanic articulations "head of the hip joint-acetabulum" are widely used for endoprosthetic operations on hip joints. Experience gained in the course of more than 2000 operations has shown that along with the advantageous properties of modern endoprosthetic constructions made of metal, ceramics and polymers, they have certain drawbacks. Among them are insufficient biological inertness and susceptibility to excessive wear of the friction pair components. In addition, as a result of wear of the hinge friction pair, toxic and oncologically dangerous products of degradation accumulate in the different organs and tissues. This in turn results in severe complications and demands correspondingly complicated corrective intervention, often leading to worse disability than that which the original operation was designed to cure. The aim of the study reported here was the development and clinical validation of a highly effective and long-lived hip joint endoprosthesis with a sapphire head whose wear capacity is superior to all others. The endoprosthesis consists of a metallic pedicle, a dismountable articulation (metallic necklayer of supramolecular polyethylene-sapphire head) and an acetabular cup. The endoprostheses with the sapphire head proved themselves positively in clinical trials and are considered to be highly promising for future applications

    Intrinsic electrophysiological properties of entorhinal cortex stellate cells and their contribution to grid cell firing fields

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    The medial entorhinal cortex (MEC) is an increasingly important focus for investigation of mechanisms for spatial representation. Grid cells found in layer II of the MEC are likely to be stellate cells, which form a major projection to the dentate gyrus. Entorhinal stellate cells are distinguished by distinct intrinsic electrophysiological properties, but how these properties contribute to representation of space is not yet clear. Here, we review the ionic conductances, synaptic, and excitable properties of stellate cells, and examine their implications for models of grid firing fields. We discuss why existing data are inconsistent with models of grid fields that require stellate cells to generate periodic oscillations. An alternative possibility is that the intrinsic electrophysiological properties of stellate cells are tuned specifically to control integration of synaptic input. We highlight recent evidence that the dorsal-ventral organization of synaptic integration by stellate cells, through differences in currents mediated by HCN and leak potassium channels, influences the corresponding organization of grid fields. Because accurate cellular data will be important for distinguishing mechanisms for generation of grid fields, we introduce new data comparing properties measured with whole-cell and perforated patch-clamp recordings. We find that clustered patterns of action potential firing and the action potential after-hyperpolarization (AHP) are particularly sensitive to recording condition. Nevertheless, with both methods, these properties, resting membrane properties and resonance follow a dorsal-ventral organization. Further investigation of the molecular basis for synaptic integration by stellate cells will be important for understanding mechanisms for generation of grid fields

    Core subjects at the end of primary school : identifying and explaining relative strengths of children with specific language impairment (SLI)

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    Background In general, children with specific language impairment (SLI) tend to fall behind their typically developing (TD) peers in educational attainment. Less is known about how children with SLI fare in particular areas of the curriculum and what predicts their levels of performance. Aims To compare the distributions of performance of children with SLI in three core school subjects (English, Mathematics and Science); to test the possibility that performance would vary across the core subjects; and to examine the extent to which language impairment predicts performance. Methods & Procedures This study was conducted in England and reports historical data on educational attainments. Teacher assessment and test scores of 176 eleven-year-old children with SLI were examined in the three core subjects and compared with known national norms. Possible predictors of performance were measured, including language ability at ages 7 and 11, educational placement type, and performance IQ. Outcomes & Results Children with SLI, compared with national norms, were found to be at a disadvantage in core school subjects. Nevertheless, some children attained the levels expected of TD peers. Performance was poorest in English; relative strengths were indicated in Science and, to a lesser extent, in Mathematics. Language skills were significant predictors of performance in all three core subjects. PIQ was the strongest predictor for Mathematics. For Science, both early language skills at 7 years and PIQ made significant contributions. Conclusions & Implications Language impacts on the school performance of children with SLI, but differentially across subjects. English for these children is the most challenging of the core subjects, reflecting the high levels of language demand it incurs. Science is an area of relative strength and mathematics appears to be intermediate, arguably because some tasks in these subjects can be performed with less reliance on verbal processing. Many children with SLI do have the potential to reach or exceed educational targets that are set at national levels for TD children

    Stochastic Risk Processes Applied to Insurance Capital Recovery Methods

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    Over recent decades, insurance and financial industries have been affected by the volatility of economic cycles. A severe financial crisis struck the market in the year 2000 and subsequently between 2007 and 2012. During these economic downturns, financial businesses (including insurance companies) experienced technical bankruptcy due to insufficient capital holdings. Therefore, the private sector and, in some cases, national governments were called upon to provide a means of recovery, in terms of capital, since their bankruptcy would cause a serious threat to the economy and community as a whole. In response to this adverse environment, governments and regulators have since drawn up stringent rules and regulations, within the insurance industry, to provide a more prudent risk assessment and, in turn, minimise the possibility of future bankruptcy. These regulations are usually known as `directives' and have been implemented across the EU, USA, Australia and China, among others. One of the most efficiently employed capital recovery methods, used in practice, is the provision of capital injections. This injection of capital is usually sourced from a companies shareholders (as long as it is profitable for them to do so) or, in some extreme cases, by the national government. Throughout the majority of this thesis, we employ the classical continuous-time risk model to analyse the financial impact of capital injections under the regulatory constraints of Solvency II and, further, by capturing the realistic procedure of financial and administrative processing linked to raising such funds, consider the risk exposure during the delay between requesting and receiving a capital injection. In the final chapter, we move to a discrete-time setting and discuss alternative capital recovery methods for a different line of business. In this case, where we consider pharmaceutical and petroleum businesses, the classic insurance risk model of the previous chapters is unsuitable and the so-called dual risk model is analysed. Moreover, it is believed that the fall into deficit (bankruptcy) can be recovered within a given time period from normal trading strategies. That is, capital injections are not required and the company can recover from deficit without financial assistance
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