bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Properties of GaSb Nanofibers
Authors: Zhou Xiuli , Guo Wei , Perez-Bergquist Alejandro G , Wei Qiangmin , Chen Yanbin , Sun Kai , Wang Lumin 
Published: August 2010

AbstractAmorphous GaSb nanofibers were obtained by ion beam irradiation of bulk GaSb single-crystal wafers, resulting in fibers with diameters of ~20 nm. The Raman spectra and photoluminescence (PL) of the ion irradiation-induced nanofibers before and after annealing were studied. Results show that the Raman intensity of the GaSb LO phonon mode decreased after ion beam irradiation as a result of the formation of the amorphous nanofibers. A new mode is observed at ~155 cm-1 both from the unannealed and annealed GaSb nanofiber samples related to the A1g mode of Sb–Sb bond vibration. Room temperature PL measurements of the annealed nanofibers present a wide feature band at ~1.4–1.6 eV. The room temperature PL properties of the irradiated samples presents a large blue shift compared to bulk GaSb. Annealed nanofibers and annealed nanofibers with Au nanodots present two different PL peaks (400 and 540 nm), both of which may originate from Ga or O vacancies in GaO. The enhanced PL and new band characteristics in nanostructured GaSb suggest that the nanostructured fibers may have unique applications in optoelectronic devices.
Biocompatibility of Graphene Oxide
Authors: Wang Kan , Ruan Jing , Song Hua , Zhang Jiali , Wo Yan , Guo Shouwu , Cui Daxiang 
Published: August 2010

AbstractHerein, we report the effects of graphene oxides on human fibroblast cells and mice with the aim of investigating graphene oxides' biocompatibility. The graphene oxides were prepared by the modified Hummers method and characterized by high-resolution transmission electron microscope and atomic force microscopy. The human fibroblast cells were cultured with different doses of graphene oxides for day 1 to day 5. Thirty mice divided into three test groups (low, middle, high dose) and one control group were injected with 0.1, 0.25, and 0.4 mg graphene oxides, respectively, and were raised for 1 day, 7 days, and 30 days, respectively. Results showed that the water-soluble graphene oxides were successfully prepared; graphene oxides with dose less than 20 μg/mL did not exhibit toxicity to human fibroblast cells, and the dose of more than 50 μg/mL exhibits obvious cytotoxicity such as decreasing cell adhesion, inducing cell apoptosis, entering into lysosomes, mitochondrion, endoplasm, and cell nucleus. Graphene oxides under low dose (0.1 mg) and middle dose (0.25 mg) did not exhibit obvious toxicity to mice and under high dose (0.4 mg) exhibited chronic toxicity, such as 4/9 mice death and lung granuloma formation, mainly located in lung, liver, spleen, and kidney, almost could not be cleaned by kidney. In conclusion, graphene oxides exhibit dose-dependent toxicity to cells and animals, such as inducing cell apoptosis and lung granuloma formation, and cannot be cleaned by kidney. When graphene oxides are explored for in vivo applications in animal or human body, its biocompatibility must be considered.
Unifying divergence bounding and locality awareness in replicated systems with vector-field consistency
Authors: Veiga Luís , Negrão André , Santos Nuno , Ferreira Paulo 
Published: August 2010

Abstract
Data replication is a very relevant technique for improving performance, availability, and scalability. These are requirements of many applications such as multiplayer distributed games, cooperative software tools, etc. However, consistency of the replicated shared state is hard to ensure. Current consistency models and middleware systems lack the required adaptability and efficiency. Thus, developing such robust applications is still a daunting task.
We propose a new consistency model, named Vector-Field Consistency (VFC) that unifies (i) several forms of consistency enforcement and a multidimensional criteria (time, sequence, and value) to limit replica divergence with (ii) techniques based on locality-awareness (w.r.t. players position).
Based on the VFC model, we propose a generic meta-architecture that can be easily instantiated both to centralized and (dynamically) partitioned architectures: (i) a single central server in which the VFC algorithm runs or (ii) a set of servers in which each one is responsible for a slice of the data being shared. The first approach is clearly more adapted to ad hoc networks of resource-constrained devices, while the second, being more scalable, is well adapted to large-scale networks. We developed and evaluated two prototypes of VFC (for ad hoc and large-scale networks) with very good performance results.
Relativistic effects on the collisionless–collisional transition of the filamentation instability in fast ignition
Authors: FIORE M. , FIÚZA F. , MARTI M. , FONSECA R. A. , SILVA L. O. 
Published: August 2010

AbstractRelativistic collisional effects on the filamentation instability are analytically and numerically investigated by comparing collisionless and collisional scenarios for a fast ignition (FI) configuration. The theoretical kinetic model, including warm species and space charge effects, predicts the preferential formation of larger filaments and the inhibition/enhancement of the instability when collisions are accounted for. These collisional effects are qualitatively and quantitatively confirmed by 1D and 2D particle-in-cell (PIC) simulations, also providing a physical picture for the inhibition/enhancement regime due to collisions, based on the electron beam slowdown. By plugging typical FI parameters in the dispersion relation, the theoretical model predicts significant growth rates of the instability deep inside the FI target, thus showing the potential role of the filamentation instability as a mechanism for energy deposition into the pellet core.
Spatial variability models of CO2 emissions from soils colonized by grass (Deschampsia antarctica) and moss (Sanionia uncinata) in Admiralty Bay, King George Island
Authors: Mendonça Eduardo de Sá , La Scala Newton , Panosso Alan Rodrigo , Simas Felipe N.B. , Schaefer Carlos E.G.R. 
Published: August 2010

AbstractSoil CO2 emission is an important part of the terrestrial carbon cycling and is influenced by several factors, such as type and distribution of vegetation. In this work we evaluated the spatial variability of soil CO2 emission in terrestrial ecosystems of maritime Antarctica, under two contrasting vegetation covers: 1) grass areas of Deschampsia antarctica Desv., and 2) moss carpets of Sanionia uncinata (Hedw.) Loeske. Highest mean emission was obtained for the Deschampsia (4.13 μmol m-2 s-1) developed on organic-rich soil with a strong penguin influence. The overall results indicate that soil temperature is not directly related to the spatial pattern of soil CO2 emission at the sites studied. Emission adjusted models were Gaussian and exponential with ranges varying from 1.3 to 2.8 m, depending on the studied site and vegetation cover.
How nurture can shape preferences: an experimental study on risk preferences of Vietnamese fishers
Authors: NGUYEN QUANG 
Published: August 2010

ABSTRACTWe combined field experiment and household survey data to investigate whether working in a risky occupation such as fishing makes fishers less risk averse than people in other occupations. The unique characteristic of Vietnam's fisheries enables us to solve the endogeneity problem of occupational choice usually found in this kind of study. We used prospect theory as the main analytical framework and developed a practical procedure to simultaneously estimate the parameters of the utility function under prospect theory. The key finding is that working in a fishery makes economic agents less risk averse than others.
Neurotoxic Effects of Three Fractions Isolated from Tityus serrulatus Scorpion Venom
Authors: Nencioni Ana Leonor A. , Carvalho Fátima F. , Lebrun Ivo , Dorce Valquiria A. Coronado , Sandoval Maria Regina L. 
Published: August 2010

Abstract:Scorpion venoms contain low molecular weight basic polypeptides, neurotoxins, that are the principal toxic agents. These toxins act on ion channels, promoting a derangement that may result in an abnormal release of neurotransmitters. In the present study we investigated some of the effects of the F, H and J fractions isolated from Tityus serrulatus scorpion venom on the central nervous system of rodents. The venom was partially purified by gel filtration chromatography. The neurotoxic effect of these fractions was studied on convulsive activity after intravenous injection, and on electrographic activity and neuronal integrity of rat hippocampus when injected directly into this brain area. The results showed that intravenous injection of the F and H fractions induced convulsions, and intrahippocampal injection caused electrographic seizures in rats and neuronal damage in specific hippocampal areas. Fraction J injected intravenously reduced the general activity of mice in the open field but induced no changes when injected into the brain. These results suggest that scorpion toxins are able to act directly on the central nervous system promoting behavioural, electrographic and histological modifications.
Protective Effect of Ebselen on Aflatoxin B1‐Induced Cytotoxicity in Primary Rat Hepatocytes
Authors: Yang Cheng‐Feng , Liu Jin , Shen Han‐Ming , Ong Choon‐Nam 
Published: August 2010

Abstract:Recent studies have shown that aflatoxin B1 enhances reactive oxygen species formation and causes oxidative damage, which may ultimately contribute to the cytotoxicity and carcinogenic effect of aflatoxin B1. Ebselen, 2‐phenyl‐1,2‐benzoisoseleazol‐3(H)‐one, a synthetic seleno‐organic compound has been shown to possess glutathione peroxidase‐like activity and free radical scavenging ability. Thus present study was designed to investigate the protective effect of ebselen on aflatoxin B1‐induced cytotoxicity in primary rat hepatocytes. Aflatoxin B1‐induced cytotoxicity and lipid peroxidation were determined by lactate dehydrogenase leakage and malondialdehyde generation, respectively. Intracellular reactive oxygen species level was measured using the fluorescent probe 2′,7′‐dichlorofluorescin diacetate, and the intracellular reduced glutathione concentration was determined with a fluorometric method. Ebselen was found to display a dose‐dependent protective effect on lactate dehydrogenase leakage and malondialdehyde generation caused by aflatoxin B1 exposure. The results also demonstrate that ebselen efficiently inhibits the intracellular reactive oxygen species formation in aflatoxin B1‐treated hepatocytes in a dose and time‐dependent manner. It was also noted that ebselen was able to increase the intracellular reduced glutathione concentration, both in the control and in aflatoxin B1‐treated hepatocytes. The protection of ebselen against aflatoxin B1 cytotoxicity, however, was not affected by lowering the concentration of intracellular reduced glutathione. The overall data indicate that ebselen possesses a potent protective effect against aflatoxin B1‐induced cytotoxicity, and the main mechanism involved in the protection may be its strong capability in inhibiting intracellular reactive oxygen species formation and preventing oxidative damage.
Sensitivity to Nitrogen Mustard Relates to the Ability of Processing DNA Damage in Chinese Hamster Ovary Cells
Authors: Møller Peter , Wassermann Karsten , Damgaard Jesper , Nexø Bjørn A. , Wallin Håkan 
Published: August 2010

Abstract:The hallmark of the excision repair pathways is the removal of DNA adducts by excision of the damaged nucleotides. In the course of repair, transient DNA strand breaks occur, which can be measured by the Comet assay. We have investigated the processing of DNA damage, mediated by nitrogen mustard, in wild‐type AA8 Chinese hamster ovary cells, and in UV5, UV20 and UV41 DNA repair deficient cell lines. Whereas DNA repair could not be detected by unscheduled DNA synthesis at nitrogen mustard doses below 10 μM, processing of nitrogen mustard‐mediated DNA damage was observed by the Comet assay at a 100‐times lower concentration. Wild‐type Chinese hamster ovary AA8 cells were able to process nitrogen mustard‐mediated DNA damage within 4–24 hr depending on the dose of nitrogen mustard (0.1–10 μM). None of the repair‐deficient cell lines was able to completely process the DNA damage induced by 10 μM nitrogen mustard. At nitrogen mustard doses that conferred 10% colony forming ability, the repair‐deficient cells had an altered processing of nitrogen mustard‐mediated DNA damage: In the AA8, UV20, and UV41 cells, the amplitude of strand breaks peaked early (within 4 hr), the level of strand breaks in the nitrogen mustard exposed UV20 and UV41 cells did not return to the baseline of the unexposed reference culture, and the peak in strand breaks in the UV5 cell line occurred after 4 hr. Our results indicate that the single cell gel electrophoresis (Comet) assay is suitable for assessing repair capability of DNA alkylations.
Bioavailability and Pharmacokinetics of Isradipine after Oral and Intravenous Administration: Half‐Life Shorter than Expected?
Authors: Christensen Hanne Rolighed , Antonsen K. , Simonsen K. , Lindekær A. , Bonde J. , Angelo Helle Riis , Kampmann Jens P. 
Published: August 2010

Abstract:Isradipine is a calcium channel‐blocking agent of the dihydropyridine type, used in the treatment of hypertension. A terminal half‐life of 8–9 hr has been reported, in several pharmacokinetic studies after oral administration of isradipine. In a yet unpublished study a much shorter half‐life was observed, and the present trial was therefore conducted in order to estimate the half‐life after intravenous administration of isradipine. The bioavailability was estimated as well. In a randomised cross‐over design ten healthy young volunteers were given either isradipine orally or an intravenous infusion. The two study periods were separated by at least 3 days. Blood samples for measurement of isradipine concentration were collected for 10–12 hr after administration and half‐life and bioavailability were estimated. Mean terminal half‐life after intravenous administration was calculated to be 2.8 hr, and the bioavailability to be 0.28. None of the 10 subjects suffered from side effects. In the present intravenous study the half‐life of isradipine seems to be of much shorter than demonstrated in previous oral studies.
Influence of Ageing on Vasomotor Responses of Human Epicardial Coronary Arteries
Authors: Opgaard Ole Saetrum , Ytterberg Hoa T. , Saxena Pramod R. , Edvinsson Lars 
Published: August 2010

Abstract:Vasomotor responses to various agonists were studied on isolated circular segments of human epicardial coronary arteries from three different age groups; 23–38 years, 40–58 years and 63–86 years. Noradrenaline had no or only weak contractile effect on coronary arteries from younger patients but induced contraction of all artery segments from older patients. The Emax value was significantly (P<0.0001) higher in arteries from the oldest group compared to each of the two younger age groups, whereas the potency was similar in all three groups. Linear regression analysis of noradrenaline‐induced contraction in individual patients revealed a significantly positive age‐correlation (correlation coefficient 0.67, P<0.0001). Contraction induced by endothelin‐1 and relaxation induced by substance P, calcitonin gene‐related peptide and vasoactive intestinal peptide on arteries precontracted with U46619 showed no significant differences in maximum responses and potencies between the three age groups, and no significant linear age‐correlation. These data demonstrate a large variability in contractile responses to noradrenaline with contractions seen mostly in coronary arteries from older patients. It thus seems that sympathetic activation could contribute to coronary ischaemia in some patients.
Effects of Various Aluminium Compounds Given Orally to Mice on Al Tissue Distribution and Tissue Concentrations of Essential Elements
Authors: Długaszek Maria , Fiejka Maria A. , Graczyk Alfreda , Aleksandrowicz Janina Cz. , Słowikowska Maria 
Published: August 2010

Abstract:To evaluate the risk of gastrointestinal long‐term aluminium (Al) exposure, aluminium distribution and the levels of the following essential elements: Ca, Mg, Zn, Cu, and Fe in tissue were studied. Aluminium was administered in drinking water as aluminium chloride, dihydroxyaluminium sodium carbonate or aluminium hydroxide. Mice (strain Pzh:SFIS) were exposed to a total dose of 700 mg Al in long‐term treatment (for each Al compound n=15). Concentrations of Al, Ca, Mg, Zn, Cu, and Fe in stomach, kidneys, bone and liver were analyzed by atomic absorption spectrometry. After AlCl3 treatment, aluminium was found to accumulate in all tested tissues. A significant decrease in Fe concentration in liver and Zn in kidneys was observed in comparison to concentrations of these elements in the control group. In the Al(OH)3‐treated group, accumulation of aluminium was observed in bone only and decline of Fe concentration in stomach and Cu in liver and kidney. In the NaAl(OH)2CO3‐treated group the increase in Al concentration was significant in bone; there was no change in concentration of essential elements in the examined tissues. The observed aluminium accumulation was not accompanied by changes in Ca and Mg concentration except for bone. This study showed that oral administration as a route of Al exposure can result in diverging accumulation of aluminium in tissues, the concentration depending on the chemical form.
Involvement of CYP3A4 in the Metabolism of Bromperidol in vitro
Authors: Sato Satoshi , Someya Toshiyuki , Shioiri Toshiki , Koitabashi Tomomi , Inoue Yoshimasa 
Published: August 2010

Abstract:In this study, human cytochrome P450 isoenzymes (CYP1A2, CYP2C19, CYP2D6, and CYP3A4) expressed in a cell line were used to elucidate their roles in the metabolism of bromperidol. We found that CYP3A4 catalyzes the N‐dealkylation of bromperidol and its metabolite, reduced bromperidol. CYP3A4 also catalyzes the dehydration of bromperidol to bromperidol 1,2,3,6‐tetrahydropyridine, metabolizes bromperidol to bromperidol pyridinium, and catalyzes the oxidation of reduced bromperidol back to bromperidol. CYP1A2, CYP2C19, and CYP2D6 do not catalyze these reactions.
Lesioning of Locus coeruleus Projections by DSP‐4 Neurotoxin Treatment: Effect on Amphetamine‐Induced Hyperlocomotion and Dopamine D2 Receptor Binding in Rats
Authors: Harro Jaanus , Meriküla Alar , Lepiku Martin , Modiri Ali‐Reza , Rinken Ago , Oreland Lars 
Published: August 2010

Abstract:DSP‐4 is a neurotoxin highly selective for the noradrenergic nerve terminals of the locus coeruleus projections. Data on the effect of DSP‐4 treatment on amphetamine‐induced hyperlocomotion are contradictory. In this study, DSP‐4 (50 mg/kg) caused reduction of noradrenaline levels by 70% in the cerebral cortex and by 79% in the cerebellum. This treatment resulted in upregulation of dopamine D2 receptors in the striatum as evidenced by [3H]‐raclopride binding. In an open field test, DSP‐4 reduced locomotor activity. D‐Amphetamine (1.5 mg/kg) caused a similar increase in locomotor activity in control and DSP‐4‐pretreated animals not familiar to the apparatus. However, when the rats were habituated to the test apparatus, the effect of amphetamine on horizontal activity was significantly larger in the DSP‐4‐pretreated animals. These data suggest that supersensitivity of D2 receptors develops after locus coeruleus denervation, but that the enhanced efficacy of amphetamine in DSP‐4‐treated rats is masked by neophobia.
Myrica nagi Attenuates Cumene Hydroperoxide‐Induced Cutaneous Oxidative Stress and Toxicity in Swiss Albino Mice
Authors: Alam Aftab , Iqbal Mohammad , Saleem Mohammad , Ahmed Salah‐uddin , Sultana Sarwat 
Published: August 2010

Abstract:In recent years, considerable efforts have been made to identify new chemopreventive agents which could be useful for man. Myrica nagi, a subtropical shrub, has been shown to possess significant activity against hepatotoxicity and other pharmacological and physiological disorders. We have shown a chemopreventive effect of Myrica nagi on cumene hydroperoxide‐induced cutaneous oxidative stress and toxicity in mice. Cumene hydroperoxide treatment at a dose level of 30 mg/animal/0.2 ml acetone enhances susceptibility of cutaneous microsomal membrane for iron‐ascorbate‐induced lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes such as catalase, glutathione peroxidase, glutathione reductase, glucose‐6‐phosphate dehydrogenase and depletion in the level of cutaneous glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes such as glutathione S‐transferase and quinone reductase has been observed. Application of Myrica nagi at doses of 2.0 mg and 4.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide (30 mg/animal/0.2 ml acetone) treatment resulted in significant inhibition of cumene hydroperoxide‐induced cutaneous oxidative stress and toxicity in a dose‐dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation induced by iron ascorbate and xanthine oxidase activities were significantly reduced (P<0.05). In addition the depleted level of glutathione, the inhibited activities of antioxidants, and phase II metabolizing enzymes were recovered to a significant level (P<0.05). The protective effect of Myrica nagi was dose‐dependent. In summary our data suggest that Myrica nagi is an effective chemopreventive agent in skin and capable of ameliorating cumene hydroperoxide‐induced cutaneous oxidative stress and toxicity.
Role of Cholecystokinin Receptors in Induction of Antinociception in Hot‐Plate Test
Authors: Rezayat Mehdi , Rahnavard Azita , Zarrindast Mohammad‐Reza 
Published: August 2010

Abstract:In the present study, the antinociceptive effect of cholecystokinin receptor agonists in the hot‐plate test in mice has been evaluated. Subcutaneous administration of cholecystokinin octapeptide (cholecystokinin‐8; 0.001, 0.005, 0.01, 0.05, and 0.1 mg/kg), unsulfated cholecystokinin octapeptide (cholecystokinin‐8U; 0.1 mg/kg) or caerulein (0.25 mg/kg) produced antinociception. Administration of the cholecystokinin tetrapeptide (cholecystokinin‐4; 0.25, 0.5 and 1.0 mg/kg) had no effect in the hot‐plate test. Subcutaneous injection of the selective cholecystokinin receptor antagonists, MK‐329 (0.125, 0.25 and 0.5 mg/kg) or L‐365,260 (0.125, 0.25 and 0.5 mg/kg), produced no antinociceptive response. When the animals were pretreated with the cholecystokinin receptor antagonists or naloxone (0.5 and 1 mg/kg), a significant decrease in the antinociceptive response induced by cholecystokinin‐8 and caerulein was obtained. The results indicate that single administration of cholecystokinin receptor agonists could produce an antinociceptive effect which is probably mediated via cholecystokinin receptors. With respect to the results obtained from morphine and naloxone administration, it is concluded that there may be an interaction between cholecystokinin and opiate mechanisms.