196 research outputs found

    Process control of directional disperse system state changes mineral hydromix

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    Рассмотрены результаты исследования структурно‐механических особенностей минеральной гидросмеси с учетом термодинамического потенциала. Созданы предпосылки не только теоретического обоснования процесса, но и развития прикладных исследований в области создания технологий и средств переработки и обогащения полезных ископаемых экологически безопасными способами.Reviewed the results of a study of structural‐mechanical characteristics of mineral slurries with view of thermodynamic potential. Set the stage not only theoretical justification process, but also the development of applied research in the field of creation of technologies and means of processing and dressing mineral resources in environmentally friendly ways

    Antinociceptive effects of epidural magnesium sulphate alone and in combination with morphine in dogs

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    OBJECTIVE : To compare the antinociceptive effects of magnesium sulphate (MgSO4) when administered epidurally alone and in combination with morphine. STUDY DESIGN : Experimental, randomized, ‘blinded’, crossover study. ANIMALS : Six healthy adult Beagle dogs. METHODS : Evaluated treatments were MgSO4 (2.5 mg kg 1) alone (Mg), morphine (0.1 mg kg 1) alone (Mo), MgSO4 in combination with morphine (Mm), and sterile water (0.115 mL kg 1; Co) that were injected in the lumbosacral epidural space using an epidural catheter. Antinociception was measured using the von Frey mechanical threshold device applied to the carpal pads, both sides of the thorax and metatarsi. Measurements were obtained at time points: before treatment (baseline) and 0.5, 1, 2, 4, 6, 12, 18 and 24 hours after the epidural injection. Sedation, behaviour score and presence of motor deficits were assessed. Data were analyzed using a linear mixed model and Bonferroni adjustments, with significance set at p < 0.05. RESULTS : There were significant effects of treatment and time in all regions. Overall threshold values in grammes force [median (interquartile range)] when stimulation regions were combined were significantly higher in Mg [164 (135–200)], Mo 156 (129–195)] and Mm [158 (131–192)] compared to Co [145 (120–179)]. Thresholds were significantly higher compared to Co in Mg, Mo and Mm at the thorax and metatarsi, but only in Mg and Mo at the carpal pads. No motor deficits were observed at any time point. Thresholds (combined regions) were increased from baseline at one or more time points with all treatments, including control. CONCLUSION AND CLINICAL RELEVANCE : Epidural MgSO4 produced an antinociceptive effect characterised by an increase in the mechanical thresholds of similar magnitude to that produced by epidural morphine, compared with the control group, without causing any motor deficits. No potentiation of morphine antinociception was observed. The onset and offset times of antinociception could not be clearly established. To what extent these results can be extrapolated to clinical cases requires further investigation.Department of Companion Animal Clinical Studies of the University of Pretoria and the University of Pretoria Research Fund.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1467-29952016-05-31hb201

    Probing the solution structure of the E. coli multidrug transporter MdfA using DEER distance measurements with nitroxide and Gd(III) spin labels

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    Methodological and technological advances in EPR spectroscopy have enabled novel insight into the structural and dynamic aspects of integral membrane proteins. In addition to an extensive toolkit of EPR methods, multiple spin labels have been developed and utilized, among them Gd(III)-chelates which offer high sensitivity at high magnetic fields. Here, we applied a dual labeling approach, employing nitroxide and Gd(III) spin labels, in conjunction with Q-band and W-band double electron-electron resonance (DEER) measurements to characterize the solution structure of the detergent-solubilized multidrug transporter MdfA from E. coli. Our results identify highly flexible regions of MdfA, which may play an important role in its functional dynamics. Comparison of distance distribution of spin label pairs on the periplasm with those calculated using inward- and outward-facing crystal structures of MdfA, show that in detergent micelles, the protein adopts a predominantly outward-facing conformation, although more closed than the crystal structure. The cytoplasmic pairs suggest a small preference to the outward-facing crystal structure, with a somewhat more open conformation than the crystal structure. Parallel DEER measurements with the two types of labels led to similar distance distributions, demonstrating the feasibility of using W-band spectroscopy with a Gd(III) label for investigation of the structural dynamics of membrane proteins.This work was supported by the German-Israeli Foundation for Scientific Research and Development to E.B. (GIF, Grant Number I-1202-248.9/2012), the Clore Center of Biological Physics at the Weizmann Institute of Science to D.G. and E.B., by a grant from the United States - Israel Binational Science Foundation (BSF), Jerusalem, Israel to H.S.M. and E.B., and by a grant from the Minerva Foundation to D.G. E.H.Y is the recipient of a Professor Rahamimoff Travel Grant from the United States - Israel Binational Science Foundation. T.B. acknowledges financial support from the Minerva Foundation. The authors would like to thank Dr. Akiva Feintuch for his support with Gd(III) AWG-DEER measurements

    Positive and Negative Regulation of Prostate Stem Cell Antigen Expression by Yin Yang 1 in Prostate Epithelial Cell Lines

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    Prostate cancer is influenced by epigenetic modification of genes involved in cancer development and progression. Increased expression of Prostate Stem Cell Antigen (PSCA) is correlated with development of malignant human prostate cancer, while studies in mouse models suggest that decreased PSCA levels promote prostate cancer metastasis. These studies suggest that PSCA has context-dependent functions, and could be differentially regulated during tumor progression. In the present study, we identified the multi-functional transcription factor Yin Yang 1 (YY1) as a modulator of PSCA expression in prostate epithelial cell lines. Increased YY1 levels are observed in prostatic intraepithelial neoplasia (PIN) and advanced disease. We show that androgen-mediated up-regulation of PSCA in prostate epithelial cell lines is dependent on YY1. We identified two direct YY1 binding sites within the PSCA promoter, and showed that the upstream site inhibited, while the downstream site, proximal to the androgen-responsive element, stimulated PSCA promoter activity. Thus, changes in PSCA expression levels in prostate cancer may at least partly be affected by cellular levels of YY1. Our results also suggest multiple roles for YY1 in prostate cancer which may contribute to disease progression by modulation of genes such as PSCA

    Causes and mechanisms of synchronous succession trajectories in primeval Central European mixed Fagus sylvatica forests

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    1. Natural succession trajectories of Central European forest ecosystems are poorly understood due to the absence of long‐term observations and the pervasive effects of past human impacts on today's vegetation communities. This knowledge gap is significant given that currently forest ecosystems are expanding in Europe as a consequence of global change. 2. Annually laminated sediments were extracted from two small lowland lakes (Moossee 521 m a.s.l.; Burgäschisee 465 m a.s.l.) on the Swiss Plateau. We combine high‐resolution palaeoecological and quantitative analyses to assess changes in vegetation during the Neolithic. We test for regionally synchronous land‐use phases and plant successional patterns that may originate from complex interactions between human and climatic impacts. 3. Mixed Fagus sylvatica forests dominated the Swiss Plateau vegetation over millennia. During the period 6,500-4,200 cal year bp, pronounced forest disruptions accompanied by increased fire and agricultural activities occurred at c. 6,400-6,000 cal year bp, 5,750-5,550 cal year bp, around 5,400 cal year bp and at 5,100-4,600 cal year bp. Biodiversity increased during these land‐use phases, likely in response to the creation of new open habitats. After decades to centuries of land‐use, arboreal vegetation re‐expanded. In a first succession stage, heliophilous Corylus avellana shrubs were replaced by pioneer Betula trees. These open arboreal communities were out‐competed within 150-200 years by late‐successional  F. sylvatica and Abies alba forests. Most strikingly, cross‐correlations show that these successions occurred synchronously (±11 years) and repeatedly over large areas (&gt;1,000 km2) and millennia. 4. Synthesis. First notable human impact shaped the primeval mixed Fagus sylvatica forests in Central Europe from c. 6,800-6,500 cal year bp on. Agrarian societies were susceptible to climate changes and we hypothesize that climate‐induced, simultaneous agricultural expansion and contraction phases resulted in synchronous regional forest successions. Currently, forests are expanding in Central Europe as a result of land abandonment in marginal areas. Our results imply that mixed Fagus sylvatica forests with Abies alba and Quercus may re‐expand rapidly in these areas, if climate conditions will remain within the range of the mid‐Holocene climatic variability (with summers c. +1-2°C warmer than today)
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