372 research outputs found

    Optical precursors in transparent media

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    We theoretically study the linear propagation of a stepwise pulse through a dilute dispersive medium when the frequency of the optical carrier coincides with the center of a natural or electromagnetically induced transparency window of the medium (slow-light systems). We obtain fully analytical expressions of the entirety of the step response and show that, for parameters representative of real experiments, Sommerfeld-Brillouin precursors, main field and second precursors "postcursors" can be distinctly observed, all with amplitudes comparable to that of the incident step. This behavior strongly contrasts with that of the systems generally considered up to now

    Law Enforcement as Discretion and Legal Process

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    This article investigates the analytical and synthesis aspects of a wide range of sources, considering law enforcement from a dual perspective: as legal discretion and as a kind of legal process. This research applied the classical methodology of qualitative analysis of systems and processes, in particular, a system-analytical approach to the study of research object

    Additive Laser Excitation of Giant Nonlinear Surface Acoustic Wave Pulses

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    The laser ultrasonics technique perfectly fits the needs for non-contact, non-invasive, non-destructive mechanical probing of samples of mm to nm sizes. This technique is however limited to the excitation of low-amplitude strains, below the threshold for optical damage of the sample. In the context of strain engineering of materials, alternative optical techniques enabling the excitation of high amplitude strains in a non-destructive optical regime are seeking. We introduce here a non-destructive method for laser-shock wave generation based on additive superposition of multiple laser-excited strain waves. This technique enables strain generation up to mechanical failure of a sample at pump laser fluences below optical ablation or melting thresholds. We demonstrate the ability to generate nonlinear surface acoustic waves (SAWs) in Nb:SrTiO3_3 substrates, at typically 1 kHz repetition rate, with associated strains in the percent range and pressures close to 100 kbars. This study paves the way for the investigation of a host of high-strength SAW-induced phenomena, including phase transitions in conventional and quantum materials, plasticity and a myriad of material failure modes, chemistry and other effects in bulk samples, thin layers, or two-dimensional materials

    Interpolated wave functions for nonadiabatic simulations with the fixed-node quantum Monte Carlo method

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    Simulating nonadiabatic effects with many-body wave function approaches is an open field with many challenges. Recent interest has been driven by new algorithmic developments and improved theoretical understanding of properties unique to electron-ion wave functions. Fixed-node diffusion Monte Caro is one technique that has shown promising results for simulating electron-ion systems. In particular, we focus on the CH molecule for which previous results suggested a relatively significant contribution to the energy from nonadiabatic effects. We propose a new wave function ansatz for diatomic systems which involves interpolating the determinant coefficients calculated from configuration interaction methods. We find this to be an improvement beyond previous wave function forms that have been considered. The calculated nonadiabatic contribution to the energy in the CH molecule is reduced compared to our previous results, but still remains the largest among the molecules under consideration.Comment: 7 pages, 3 figure

    Biochemical evidence for an alternate pathway in N-linked glycoprotein biosynthesis

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    Asparagine-linked glycosylation is a complex protein modification conserved among all three domains of life. Herein we report the in vitro analysis of N-linked glycosylation from the methanogenic archaeon Methanococcus voltae. Using a suite of synthetic and semisynthetic substrates, we show that AglK initiates N-linked glycosylation in M. voltae through the formation of α-linked dolichyl monophosphate N-acetylglucosamine, which contrasts with the polyprenyl diphosphate intermediates that feature in both eukaryotes and bacteria. Notably, AglK has high sequence homology to dolichyl phosphate β-glucosyltransferases, including Alg5 in eukaryotes, suggesting a common evolutionary origin. The combined action of the first two enzymes, AglK and AglC, afforded an α-linked dolichyl monophosphate glycan that serves as a competent substrate for the archaeal oligosaccharyl transferase AglB. These studies provide what is to our knowledge the first biochemical evidence revealing that, despite the apparent similarity of the overall pathways, there are actually two general strategies to achieve N-linked glycoproteins across the domains of life.National Institutes of Health (U.S.) (Grant GM039334

    Provision for Sanitary Epidemiological Welfare of the Population of the Jewish Autonomous Region during High Water and Post-Flooding Period

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    Put forward was operational protocol as regards Rospotrebnadzor institutions policies in the territory of the Jewish Autonomous Region for the prevention of epidemiological implications during the post-flooding period in reference to infectious diseases. Carried out were control measures over infection morbidity rate, drinking water quality, disinfection of water supply sources, as well as sewage systems. Actions undertaken made it possible to prevent cluster cases of infectious diseases both in the flooded areas and at the temporal accommodation sites; to provide control over acute intestinal and natural-focal disease incidence, keeping it to the level of long-term average annual indexes; and to supply the population with drinking water of high quality

    Нарушения в тромбоцитарном звене гемостаза больных острым гепатитом В

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    Обследовано 90 больных острым гепатитом В с различной тяжестью течения болезни. В сыворотке крови и эритроцитах больных изучали концентрацию диеновых конъюгатов и малонового диальдегида. Исследовали показатели тромбоцитарного звена гемостаза: количество тромбоцитов, степень и время агрегации тромбоцитов. Установлено уменьшение количества тромбоцитов, повышение степени и удлинение времени агрегации тромбоцитов в первые дни желтушного периода.90 patients with diff erent forms of acute hepatitis B were examined. Concentration of dienic conjugates and malonic dialdehyde were investigated in patients’ serum and erythrocytes. Indexes of hemostasis trombocytes chain were studied: trombocytes’ number, degree and time of trombocytes’ aggregation. Decreasing of trombocytes’ number, increasing of degree and prolongation of time of trombocytes’ aggregation were found

    Effects of estrogens and bladder inflammation on mitogen-activated protein kinases in lumbosacral dorsal root ganglia from adult female rats

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    BACKGROUND: Interstitial cystitis is a chronic condition associated with bladder inflammation and, like a number of other chronic pain states, symptoms associated with interstitial cystitis are more common in females and fluctuate during the menstrual cycle. The aim of this study was to determine if estrogens could directly modulate signalling pathways within bladder sensory neurons, such as extracellular signal-related kinase (ERK) and p38 mitogen-activated protein (MAP) kinases. These signalling pathways have been implicated in neuronal plasticity underlying development of inflammatory somatic pain but have not been as extensively investigated in visceral nociceptors. We have focused on lumbosacral dorsal root ganglion (DRG) neurons projecting to pelvic viscera (L1, L2, L6, S1) of adult female Sprague-Dawley rats and performed both in vitro and in vivo manipulations to compare the effects of short- and long-term changes in estrogen levels on MAPK expression and activation. We have also investigated if prolonged estrogen deprivation influences the effects of lower urinary tract inflammation on MAPK signalling. RESULTS: In studies of isolated DRG neurons in short-term (overnight) culture, we found that estradiol and estrogen receptor (ER) agonists rapidly stimulated ER-dependent p38 phosphorylation relative to total p38. Examination of DRGs following chronic estrogen deprivation in vivo (ovariectomy) showed a parallel increase in total and phosphorylated p38 (relative to beta-tubulin). We also observed an increase in ERK1 phosphorylation (relative to total ERK1), but no change in ERK1 expression (relative to beta-tubulin). We observed no change in ERK2 expression or phosphorylation. Although ovariectomy increased the level of phosphorylated ERK1 (vs. total ERK1), cyclophosphamide-induced lower urinary tract inflammation did not cause a net increase of either ERK1 or ERK2, or their phosphorylation. Inflammation did, however, cause an increase in p38 protein levels, relative to beta-tubulin. Prior ovariectomy did not alter the response to inflammation. CONCLUSIONS: These results provide new insights into the complex effects of estrogens on bladder nociceptor signalling. The diversity of estrogen actions in these ganglia raises the possibility of developing new ways to modulate their function in pelvic hyperactivity or pain states

    Фитохимические основы создания препаратов для литолиза оксалатных конкрементов

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    The aim of this work was to search for and study new phytopreparations based on natural plant materials (medicinal plants) that are necessary for effective litholysis of oxalate stones in patients with urolithiasis. New phytomedications were proposed and studied in which litholytic action is due to the presence of certain combinations of flavonoids and some other types of biologically active substances. In a study carried out to obtain total extracts of natural flavonoids from several medicinal plants obtained and studied litholytic properties of new pharmaceutical compositions together with previously known herbal remedies. The effectiveness of the new phytopreparations demonstrated by native oxalate calculi different composition isolated from patients with urolithiasis after surgical management.В статье рассматриваются особенности применения фитопрепаратов для профилактики и лечения мочекаменной болезни, в частности, оксалатного нефролитиаза
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