141 research outputs found

    CORRELATING THE MAGNITUDE AND SPATIAL GRADIENT OF ALTERNANS

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    Electrical restitution has been shown to inaccurately predict the occurrence of alternans of action potential duration. A new method using the spatial gradient of alternans (SGA) is proposed to predict alternans and cardiac electrical stability. A simulated 1-D strand of tissue was used to compare indexes computed from restitution methods and the SGA method to changes in the amplitude of alternans using different electro-physiological alterations. The SGA method correlated better with changes in the amplitude of alternans than restitution methods for a decrease in the transient outward current (Ito) and conduction velocity. Restitution methods correlated better with changes in the amplitude of alternans than the SGA method when the inward rectifier potassium current (Ik1) and the delayed rectifier potassium current (Ikr) were decreased. Restitution methods and the SGA method correlated well with changes in the amplitude of alternans when the L-type calcium channel current (ICaL) was altered and when Ikr, Ik1, and the sodium/calcium exchange current (INaCa) were increased. The SGA method includes the effect of conduction in tissue and reveals other features that provide advantages in predicting stability over currently used restitution methods

    Testing the Integrated Theory of Health Behaviour Change for Postpartum Weight Management

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    Aim.  This is a report of a correlational study to test the Integrated Theory of Health Behaviour Change within the context of postpartum weight self‐management including the impact of race/ethnicity and weight classification. Background.  Women experiencing childbirth face increasing challenges to manage their weight postpartum. Little is known about women’s weight self‐management during the complex physiological and psychosocial transition of the postpartum period. Methods.  Data were collected during the birth hospitalization and 4 months postbirth during 2005 and 2006. A quota sample of 250 postpartum women using two strata, race/ethnicity and prepregnant weight classification, were enrolled; 179 women completed the follow‐up survey. A survey questionnaire measured concepts from the Integrated Theory of Health Behaviour Change concepts, including knowledge and beliefs (self‐efficacy, outcome expectancy and goal congruence), self‐regulation skills and abilities, and social facilitation (social support and social influence) and the proximal outcome of weight retention. Factor analysis identified 5 factors consistent with the theoretical concepts that accounted for 47·1% of total survey variance. Results.  Model testing using path analysis explored the relationship among factors. The final model explained 25·7% of the variance in self regulation at 4 months, but did not explain weight retention. The contribution of select concepts to total variance was different for Caucasian and African American women, but not by weight classification. Conclusions.  Findings support use of theoretical concepts and relationships to understand postpartum weight self‐management. The different relationships among concepts in Caucasian and African American women should be considered in planning targeted postpartum weight self‐management interventions

    Pseudo-archaic English: The modern perception and interpretation of the linguistic past

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    This paper introduces a new project currently in its planning stages. It is dedicated to pseudoarchaic English, an area in linguistic studies which has so far hardly received any academic attention. After providing some historical examples a brief selection of some present-day occurrences as well as inspirational sources for these is given. Sample cases of pseudo-archaic English from various linguistic categories are presented in order to illustrate the wide range of its usage. Some remarks on modern perceptions of the linguistic past and their role in creating pseudo-archaic forms are provided and followed by suggestions on what still needs to be done in this field

    Veränderungen des Rb-Sr- und U-Pb-Systems im Granit von Soultz-sous-Forêts unter dem Einfluss hydrothermaler Fluide

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    In der vorliegenden Arbeit wurden Untersuchungen mit der Rb-Sr- und U-Pb-Methode an Bohrkernproben des Granits von Soultz-sous-Forêts/Frankreich durchgeführt. Die Proben stammen aus 1500 – 2200 m Tiefe und waren dort multiepisodischen Hydrothermalereignis-sen bei erhöhten Temperaturbedingungen (100 – 150°C) ausgesetzt. Das untersuchte Hartge-stein eignet sich als natürliches Archiv der komplexen Geschichte der Fluid-Gesteins-Wech-selwirkungen, die sich im Untergrund des heutigen Rheingrabens in den letzten 330 Ma abge-spielt haben. Es wurden Gesamtgesteinsproben und Hauptminerale wie Plagioklas, Kalifeld-spat, Biotit, daneben aber auch Apatit sowie das sekundäre Alterationsprodukt Chlorit unter-sucht. Ziel der Untersuchungen war es, mit Hilfe der Gesteins- und Mineral-Analysen im Detail zu rekonstruieren, in welchen Mengen und wann es zur Mobilisierung von Uran und Blei sowie Rubidium und Strontium unter dem Einfluss von Hydrothermalaktivitäten der letzten 330 Ma gekommen ist. Die Studie des isotopengeochemischen Verhaltens der untersuchten Elemente im Granit kann helfen zu bewerten, unter welchen Bedingungen die Granitmatrix über lange Zeiträume ein guter Speicher für die Stoffgruppen der Alkali- und Erdalkalielemente sowie Aktiniden und Schwermetalle gewesen ist

    Electron Microprobe Analysis and Proton Induced X-Ray Spectrometry Applied to Trace Element Analysis in Sulfides: Problems and Prospects

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    The complementary techniques of EPMA and micro-PIXE are reviewed in the context of spatially resolved trace element analysis of sulfide minerals. Attention is focussed on methods of standardization and of fitting EDX spectra. Sphalerites and chalcopyrites from various sources are used as specimens. For Ag in chalcopyrites, the two techniques agree well. Sphalerites pose problems such as Zn-Fe replacement and the presence of minor elements, both of which influence matrix corrections ; these are addressed in detail. The necessity for absorbers in the micro-PIXE work prevents detection of minor elements lighter than Zn ; these are determined by EPMA and the results used in the micro-PIXE fitting and matrix corrections. For Cd, Ag, Ga, Ge there is acceptable agreement between the two techniques given uncertainties and constraints on samples, but EPMA results for Hg are notably lower than micro-PIXE results. The improvement in detection limits afforded by micro-PIXE over EPMA in these sulfide minerals ranges from ~ 3 for Ga, Ge, Hg to 10-30 for Se, Ag, Cd, In ; possible further gains are discussed for both techniques

    Autonomic Nervous System Function Following Prenatal Opiate Exposure

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    In utero exposure to opiates may affect autonomic functioning of the fetus and newborn. We investigated heart rate variability (HRV) as a measure of autonomic stability in prenatal opiate-exposed neonates (n = 14) and in control term infants (n = 10). Electrocardiographic data during both non-nutritive and nutritive sucking were evaluated for RR intervals, heart rate (HR), standard deviation of the consecutive RR intervals (SDRR), standard deviation of the differences of consecutive RR intervals (SDDRR), and the power spectral densities in low and high frequency bands. In controls, mean HR increased significantly, 143-161 per min (p = 0.002), with a trend toward a decrease in RR intervals from non-nutritive to nutritive sucking; these measures did not change significantly among exposed infants. Compared to controls, exposed infants demonstrated significantly greater HRV or greater mean SDRR and SDDRR during non-nutritive period (p \u3c 0.01), greater mean SDDRR during nutritive sucking (p = 0.02), and higher powers in the low and high frequency bands during nutritive feedings. Our findings suggest that prenatal opiate exposure may be associated with changes in autonomic nervous system (ANS) functioning involving both sympathetic and parasympathetic branches. Future studies are needed to examine the effects of prenatal opiate exposure on ANS function

    Epstein-Barr virus and malaria upregulate AID and APOBEC3 enzymes, but only AID seems to play a major mutagenic role in Burkitt lymphoma

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    Endemic Burkitt lymphoma (eBL) is characterized by an oncogenic IGH/c-MYC translocation and Epstein-Barr virus (EBV) positivity, and is epidemiologically linked to Plasmodium falciparum malaria. Both EBV and malaria are thought to contribute to eBL by inducing the expression of activation-induced cytidine deaminase (AID), an enzyme involved in the IGH/c-MYC translocation. AID/apolipoprotein B mRNA editing catalytic polypeptide-like (AID/APOBEC) family enzymes have recently emerged as potent mutagenic sources in a variety of cancers, but apart from AID, their involvement in eBL and their regulation by EBV and P. falciparum is unknown. Here, we show that upon inoculation with EBV, human B cells strongly upregulate the expression of enzymatically active APOBEC3B and APOBEC3G. In addition, we found significantly increased levels of APOBEC3A in B cells of malaria patients, which correlated with parasite load. Interestingly, despite the fact that APOBEC3A, APOBEC3B, and APOBEC3G caused c-MYC mutations when overexpressed in HEK293T cells, a mutational enrichment in eBL tumors was only detected in AID motifs. This suggests that even though the EBV- and P. falciparum-directed immune response triggers the expression and activity of several AID/APOBEC members, only the upregulation of AID has oncogenic consequences, while the induction of the APOBEC3 subfamily may primarily have immunoprotective functions

    CD4 + T cells are found within endemic Burkitt lymphoma and modulate Burkitt lymphoma precursor cell viability and expression of pathogenically relevant Epstein-Barr virus genes.

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    Endemic Burkitt lymphoma (eBL) is an aggressive B cell cancer characterized by an IgH/c-myc translocation and the harboring of Epstein-Barr virus (EBV). Evidence accumulates that CD4 + T cells might contribute to eBL pathogenesis. Here, we investigate the presence of CD4 + T cells in primary eBL tissue and their potential dichotomous impact on an EBV-infected pre-eBL cell model using ex vivo material and in vitro co-cultures. In addition, we establish a novel method to study the effect of IgH/c-myc translocation in primary B cells by employing a CRISPR/Cas9 knock-in approach to introduce and tag de novo translocation. We unprecedently document that CD4 + T cells are present in primary eBL tumor tissue. Furthermore, we demonstrate that CD4 + T cells on the one hand suppress eBL development by killing pre-eBL cells lacking IgH/c-myc translocation in vitro and on the other hand indirectly promote eBL development by inducing crucial EBV Latency III to Latency I switching in pre-eBL cells. Finally, we show that while the mere presence of an IgH/c-myc translocation does not suffice to escape CD4 + T-cell-mediated killing in vitro, the CD4 + T-cell-mediated suppression of EBV's Latency III program in vivo may allow cells harboring an IgH/c-myc translocation and additional mutations to evade immune control and proliferate by means of deregulated c-myc activity, resulting in neoplasia. Thus, our study highlights the dichotomous effects of CD4 + T cells and the mechanisms involved in eBL pathogenesis, suggests mechanisms of their impact on eBL progression, and provides a novel in vitro model for further investigation of IgH/c-myc translocation

    Decomposition of skin conductance data by means of nonnegative deconvolution

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    Skin conductance (SC) data are usually characterized by a sequence of overlapping phasic skin conductance responses (SCRs) overlying a tonic component. The variability of SCR shapes hereby complicates the proper decomposition of SC data. A method is proposed for full decomposition of SC data into tonic and phasic components. A two-compartment diffusion model was found to adequately describe a standard SCR shape based on the process of sweat diffusion. Nonnegative deconvolution is used to decompose SC data into discrete compact responses and at the same time assess deviations from the standard SCR shape, which could be ascribed to the additional process of pore opening. Based on the result of single non-overlapped SCRs, response parameters can be estimated precisely as shown in a paradigm with varying inter-stimulus intervals

    Observations on the changing language of accounting

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    The meaning of words can change over time. In addition, new words may enter a language, sometimes replacing other words. This article extends prior literature on language change in accounting by drawing to a larger extent on theories from linguistics, and by placing greater emphasis on mechanisms of and motivations for change. Particular emphasis is placed on the need to verbalize new concepts, and sociocultural change. The latter is illustrated with examples from the development of accounting as an occupational interest group, and the adoption of Anglo-American accounting terminology and culture. The article concludes that language change in accounting, including transmission between languages and cultures, can inform accounting historians about the transfer of technical developments, as well as about socio-economic, political or ideological processes, power relationships, and the importance of terminology in jurisdictional disputes
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