6,163 research outputs found

    Protective effect of nitric oxide against arsenic-induced oxidative damage in tall fescue leaves

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    Nitric oxide (NO) is a key molecule involved in many physiology processes. The effects of NO on alleviating arsenic-induced oxidative damage in tall fescue leaves were investigated. Arsenic (25 M) treatment induced significantly accumulation of reactive oxygen species (ROS) and led to serious lipid peroxidation in tall fescue leaves and the application of 100 M SNP before arsenic stress resulted in alleviated arsenic-induced electrolyte leakage and malondiadehyde (MDA) content in tall fescue leaves, the levels of hydrogen peroxide (H2O2) and superoxide radical (O2̅ ) were reduced as well. Moreover, the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) increased in tall fescue leaves in presence of SNP under arsenic stress. This pattern was reversed by application of NO scavenger, 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethy-limidazoline-1-oxyl-3-oxide (PTIO) before arsenic treatment. Pronounced increases in endogenous NO production was found in plants after exposure to arsenic stress. The results suggested that arsenic stress elevated endogenous NO level and that NO might act as a signaling molecule to enhance antioxidant enzyme activities, further protecting against injuries caused by arsenic toxicity

    Acclimation of morphology and physiology in turf grass to low light environment: A review

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    This short review elucidated the significance of the research on acclimation of the morphology and physiology in turf grass to low light environment, the mechanism of physiological response and the photosynthetic regulation and control of turf grass to suit low light environment. We also discussed current research problems and provided insight into future relevant research.Key words: Low light, morphological change, physiological acclimation, regulation mechanism, turf grass

    Nucleosynthesis in Advective Accretion Disks Around Galactic and Extra-Galactic Black Holes

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    We compute the nucleosynthesis of materials inside advective disks around black holes. We show that composition of incoming matter can change significantly depending on the accretion rate and accretion disks. These works are improvements on the earlier works in thick accretion disks of Chakrabarti, Jin & Arnett (1987) in presence of advection in the flow.Comment: Latex pages including figures. Kluwer Style files included. Appearing in `Observational Evidence for Black Holes in the Universe', ed. Sandip K. Chakrabarti, Kluwer Academic Publishers (DORDRECHT: Holland

    The Dropping of In-Medium Hadron Mass in Holographic QCD

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    We study the baryon density dependence of the vector meson spectrum using the D4/D6 system together with the compact D4 baryon vertex. We find that the vector meson mass decreases almost linearly in density at low density for small quark mass, but saturates to a finite non-zero value for large density. We also compute the density dependence of the η\eta\prime mass and the η\eta\prime velocity. We find that in medium, our model is consistent with the GMOR relation up to a few times the normal nuclear density. We compare our hQCD predictions with predictions made based on hidden local gauge theory that is constructed to model QCD.Comment: 20 pages, 7 figure

    Myocarditis related to Campylobacter jejuni infection: A case report

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    BACKGROUND: Myocarditis can develop as a complication of various infections and is most commonly linked to enterovirus infections. Myocarditis is rarely associated with bacterial infections; salmonellosis and shigellosis have been the most frequently reported bacterial cause. We report a case of myocarditis related to Campylobacter jejuni enteritis. CASE PRESENTATION: A 30-year-old previously healthy man presented with a history of prolonged chest pain radiating to the jaw and the left arm. Five days prior to the onset of chest pain, he developed bloody diarrhea, fever and chills. Creatine kinase (CK) and CK-MB were elevated to 289 U/L and 28.7 μg/L. Troponin I was 30.2 μg/L. The electrocardiogram (ECG) showed T wave inversion in the lateral and inferior leads. The chest pain resolved within 24 hours of admission. The patient had a completely normal ECG stress test. The patient was initiated on ciprofloxacin 500 mg po bid when Campylobacter jejuni was isolated from the stool. Diarrhea resolved within 48 hours of initiation of ciprofloxacin. The diagnosis of Campylobacter enteritis and related myocarditis was made based on the clinical and laboratory results and the patient was discharged from the hospital in stable condition. CONCLUSION: Myocarditis can be a rare but severe complication of infectious disease and should be considered as a diagnosis in patients presenting with chest pain and elevated cardiac enzymes in the absence of underlying coronary disease. It can lead to cardiomyopathy and congestive heart failure. There are only a few reported cases of myocarditis associated with Campylobacter infection

    Longitudinal impact of process-oriented guided inquiry learning on the attitudes, self-efficacy and experiences of pre-medical chemistry students

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    A follow-up study was conducted with foundation-year chemistry students who were taught in an inquiry- and role-based, small-group active learning environment in order to evaluate their attitudes, experiences and self-efficacy during pre-medical chemistry courses. The study adopted a mixedmethods research design that involved both experimental and comparison groups. Using the CAEQ (Chemistry Attitudes and Experiences Questionnaire) and the ASCI v2 (Attitude toward the Study of Chemistry Inventory), the findings of this study indicated that inquiry-based chemistry learning experience improves the students’ intellectual accessibility and emotional satisfaction as well as develops their self-efficacy levels while pursuing intensive pre-medical courses in chemistry. The results of the qualitative data analyses using a course experience questionnaire indicated that the process-oriented guided inquiry learning (POGIL) experience helped the students succeed in rigorous pre-medical chemistry courses and gained some process skills required in the medical programme as listed by the AAMC (American Association of Medical Colleges)

    Digenean parasites of Chinese marine fishes: a list of species, hosts and geographical distribution

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    In the literature, 630 species of Digenea (Trematoda) have been reported from Chinese marine fishes. These belong to 209 genera and 35 families. The names of these species, along with their hosts, geographical distribution and records, are listed in this paper

    Recent advances on information transmission and storage assisted by noise

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    The interplay between nonlinear dynamic systems and noise has proved to be of great relevance in several application areas. In this presentation, we focus on the areas of information transmission and storage. We review some recent results on information transmission through nonlinear channels assisted by noise. We also present recent proposals of memory devices in which noise plays an essential role. Finally, we discuss new results on the influence of noise in memristors.Comment: To be published in "Theory and Applications of Nonlinear Dynamics: Model and Design of Complex Systems", Proceedings of ICAND 2012 (Springer, 2014

    Bilayer manganites: polarons in the midst of a metallic breakdown

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    The exact nature of the low temperature electronic phase of the manganite materials family, and hence the origin of their colossal magnetoresistant (CMR) effect, is still under heavy debate. By combining new photoemission and tunneling data, we show that in La{2-2x}Sr{1+2x}Mn2O7 the polaronic degrees of freedom win out across the CMR region of the phase diagram. This means that the generic ground state is that of a system in which strong electron-lattice interactions result in vanishing coherent quasi-particle spectral weight at the Fermi level for all locations in k-space. The incoherence of the charge carriers offers a unifying explanation for the anomalous charge-carrier dynamics seen in transport, optics and electron spectroscopic data. The stacking number N is the key factor for true metallic behavior, as an intergrowth-driven breakdown of the polaronic domination to give a metal possessing a traditional Fermi surface is seen in the bilayer system.Comment: 7 pages, 2 figures, includes supplementary informatio
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