1,826 research outputs found

    Inosine ameliorates the effects of hemin induced oxidative stress in broilers

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    Previous studies have shown that chronic treatment of broilers with hemin decreases plasma concentrations of uric acid and increases leukocyte oxidative activity (LOA) whereas the inclusion of inosine produces an inverse effect. The objective of these studies was to determine whether or not inosine could serve as a potential therapy for oxidative stress. Oxidative stress was induced in broilers by the administration of hemin. Dietary inclusion of inosine was then begun either before the onset of oxidative stress induced by hemin, or as a post treatment once oxidative stress was established. Four-week-old broilers were individually banded and divided into four treatment groups (Control, Hemin, Inosine, Hemin/Inosine). Throughout the study control birds (n=10) were injected daily intraperitoneal with a buffer solution, while hemin birds (n=10) were injected daily intraperitoneal with a 20mg/kg body weight hemin buffer solution. Leukocyte oxidative activity (LOA) and plasma uric acid (PUA) were measured on day eight. Results showed that hemin birds had higher levels of LOA (P=0.03) and lower PUA (P=0.11). On day 10, control and hemin birds were subdivided into inosine birds (n=5) and hemin/inosine birds (n=5). These birds were given 0.6M/kg of feed/day of dry inosine. Plasma concentrations of uric acid and LOA were then measured on day 15. Results showed that inosine raised concentrations of PUA (P=0.0001) and lowered LOA (P=0.004) induced by hemin. In a separate study, stereological analyses of inosine vs. control birds revealed no anatomical differences in kidney morphology between treatments (P=0.05). The results of these studies support the view that uric acid reduces oxidative stress by functioning as an antioxidant. Uric acid treatment has the potential to decrease the amount of damage generated by free radicals during times of oxidative stress associated with disease states

    De-centering the Monolingual: A Psychophysiological Study of Heritage Speaker Language Processing

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    Models of grammar, processing and acquisition are primarily built on evidence from monolinguals and adult learners of a second language. Heritage speakers, who are bilinguals of a societal minority language, acquire and use their heritage language in informal settings; but who live, work, and are educated in the societal majority language. The differences between heritage speakers and both monolinguals and adult second language learners are extensive: heritage speakers are not educated in the heritage language, their input is typically not from a prestige variety of the heritage language, and they are dominant in the majority language, using it more frequently (Valdés, 1989). Previous research of heritage speaker characterized their grammars as simple, decayed/attrited, and incomplete (Benmamoun, Montrul, & Polinsky, 2010; Scontras, Fuchs, & Polinsky, 2015), and are compared to intermediate second language learner grammars (Montrul, 2005). The present study: 1) explores the language use and exposure of heritage speakers, 2) examines their performance on metalinguistic tasks, and 3) measures language processing using implicit measures (event-related potentials and pupillometry). Heritage speakers are compared to adult late second language learners living and working in a second language dominant society from the same community. The study focuses on fluent Spanish and English Latinx bilinguals living in the anglophone US. Spanish heritage speakers are appropriately compared to their time-apparent parents (English speaking Latinx immigrants who moved to the anglophone US in adulthood). Online language processing of subject- and object-relative clauses are examined as the subject-object relative clause processing asymmetry has been well-established in both Spanish and English, is early acquired, and is not confounded by prescriptive rules or literacy

    Experiments on Steady-State Nonisothermal Moisture Movement in Wood

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    The study was conducted to measure experimentally the steady-state uniaxial (tangential direction) moisture content and temperature profiles in moisture-sealed wood samples whose opposite faces were subjected to constant but different temperatures, and to compare these profiles with those predicted by several theoretical models. The experimental variables considered were wood species, initial moisture content, and temperature range.Opposite faces of the moisture-sealed assembly were exposed continuously for approximately five weeks to different but constant temperatures until the original uniform moisture content redistributed itself. At the steady state, a moisture content gradient opposite to the temperature gradient was established. The temperature gradient was constant in all cases, with the moisture content profile increasing almost exponentially with decreasing temperature. The absolute value of the ratio of the moisture content gradient to the temperature gradient (dM/dT)s was found to increase with wood moisture content and was observed to be higher at the higher temperature range. There was only a small difference in the -(dM/dT)s between the two species studied.The ratio -(dM/dT)s was analyzed in terms of five different theoretical models, two of which are based on nonequilibrium thermodynamics (NET) and three on classical thermodynamics. The two NET models (basic NET and Nelson models) provided the best agreement with the experimental values. The Siau model gave the next best prediction, followed by the Stanish model, and lastly by the Skaar-Siau model

    On narrowing coated conductor film: emergence of granularity-induced field hysteresis of transport critical current

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    Critical current density Jc in polycrystalline or granular superconducting material is known to be hysteretic with applied field H due to the focusing of field within the boundary between adjacent grains. This is of concern in the so-called coated conductors wherein superconducting film is grown on a granular, but textured surface of a metal substrate. While previous work has mainly been on Jc determined using induced or magnetization currents, the present work utilizes transport current via an applied potential in strip geometry. It is observed that the effect is not as pronounced using transport current, probably due to a large difference in criterion voltage between the two types of measurements. However, when the films are narrowed by patterning into 200-, 100-, or 80-micron, the hysteresis is clearly seen, because of the forcing of percolation across higher-angle grain boundaries. This effect is compared for films grown on ion-beam-assisted-deposited (IBAD) YSZ substrate and those grown on rolling-assisted-biaxially-textures substrates (RABiTS) which have grains that are about ten times larger. The hysteresis is more pronounced for the latter, which is more likely to have a weak grain boundary spanning the width of the microbridge. This is also of concern to applications in which coated conductors will be striated in order to reduce of AC losses.Comment: text-only: 10 pages, plus 5 figures on 5 page

    Matrix Metalloproteinase-9 in Pneumococcal Meningitis: Activation via an Oxidative Pathway

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    In experimental bacterial meningitis, matrix metalloproteinases (MMPs) and reactive oxygen species (ROS) contribute to brain damage. MMP-9 increases in cerebrospinal fluid (CSF) during bacterial meningitis and is associated with the brain damage that is a consequence of the disease. This study assesses the origin of MMP-9 in bacterial meningitis and how ROS modulate its activity. Rat brain-slice cultures and rat polymorphonuclear cells (PMNs) that had been challenged with capsule-deficient heat-inactivated Streptococcus pneumoniae R6 (hiR6) released MMP-9. Coincubation with either catalase, with the myeloperoxidase inhibitor azide, or with the hypochlorous acid scavenger methionine almost completely prevented activation, but not the release, of MMP-9, in supernatants of human PMNs stimulated with hiR6. Thus, in bacterial meningitis, both brain-resident cells and invading PMNs may act as sources of MMP-9, and stimulated PMNs may activate MMP-9 via an ROS-dependent pathway. MMP-9 activation by ROS may represent a target for therapeutic intervention in bacterial meningiti

    Low Frequency Quantum Transport in a Three-probe Mesoscopic Conductor

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    The low frequency quantum transport properties of a three-probe mesoscopic conductor are studied using B\"uttiker's AC transport formalism. The static transmission coefficients and emittance matrix of the system were computed by explicitly evaluating the various partial density of states (PDOS). We have investigated the finite size effect of the scattering volume on the global PDOS. By increasing the scattering volume we observed a gradual improvement in the agreement of the total DOS as computed externally or locally. Our numerical data permits a particular fitting form of the finite size effect.Comment: 13 pages, LaTeX, submitted to Phys. Rev.

    An improved continuous compositional-spread technique based on pulsed-laser deposition and applicable to large substrate areas

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    A new method for continuous compositional-spread (CCS) thin-film fabrication based on pulsed-laser deposition (PLD) is introduced. This approach is based on a translation of the substrate heater and the synchronized firing of the excimer laser, with the deposition occurring through a slit-shaped aperture. Alloying is achieved during film growth (possible at elevated temperature) by the repeated sequential deposition of sub-monolayer amounts. Our approach overcomes serious shortcomings in previous in-situ implementations of CCS based on sputtering or PLD, in particular the variations of thickness across the compositional spread and the differing deposition energetics as function of position. While moving-shutter techniques are appropriate for PLD-approaches yielding complete spreads on small substrates (i.e. small as compared to distances over which the deposition parameters in PLD vary, typically about 1 cm), our method can be used to fabricate samples that are large enough for individual compositions to be analyzed by conventional techniques, including temperature-dependent measurements of resistivity and dielectric and magnetic and properties (i.e. SQUID magnetometry). Initial results are shown for spreads of (Sr,Ca)RuO3_3.Comment: 6 pages, 8 figures, accepted for publication in Rev. Sci. Instru

    Charge injection instability in perfect insulators

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    We show that in a macroscopic perfect insulator, charge injection at a field-enhancing defect is associated with an instability of the insulating state or with bistability of the insulating and the charged state. The effect of a nonlinear carrier mobility is emphasized. The formation of the charged state is governed by two different processes with clearly separated time scales. First, due to a fast growth of a charge-injection mode, a localized charge cloud forms near the injecting defect (or contact). Charge injection stops when the field enhancement is screened below criticality. Secondly, the charge slowly redistributes in the bulk. The linear instability mechanism and the final charged steady state are discussed for a simple model and for cylindrical and spherical geometries. The theory explains an experimentally observed increase of the critical electric field with decreasing size of the injecting contact. Numerical results are presented for dc and ac biased insulators.Comment: Revtex, 7pages, 4 ps figure

    Antibiotic Resistance

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    Our poster discusses an overview of antibiotic resistance. It goes into detail about what it is, how it came to be, and what medical professionals can do in their attempt to prevent it, as well as the general public. It also discusses the impact the impact antibiotic resistance has had on pharmacy, as well as the science behind it. A few organizations working towards this problem, and who keep a close eye on this issue are mentioned as well. We also discuss the determinants of health, which is essentially what is being done about it politically, individually, and the health services provided. Our goal is to stress the importance of properly taking antibiotics, and the potential to prevent this problem from happening. We hope you take some insight behind this issue after reading, and sparks an interest in this topic.https://digitalcommons.cedarville.edu/public_health_posters/1020/thumbnail.jp
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