1,192 research outputs found

    NBS as a Powerful Catalyst for the Synthesis of β-Hydroxysulphides with Thiolysis of Epoxides under Mild Reaction Conditions

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    N-Bromosuccinimide (NBS) catalyses the ring opening of various epoxides with different thiols in CH3CN at room temperature under mild reaction conditions. The corresponding β-hydroxysulphides are obtained in short reaction times and in good to high yields with nearly complete regioselectivity. The catalyst was compared with previously reported catalysts and only one that we have found [B(C6F5)3] gave the same regioselectivity, but the reaction time was much longer (4 h versus 5 min) and the yield was considerably lower. Zn(ClO4)2.6H2O gave slightly lower selectivity but higher yields. The reaction time was about 12 times longer.Keywords: N-Bromosuccinimide, thiols, ring opening, epoxides, β-hydroxysulphide

    The effects of creosote on mortality rate and blood biochemical factors of stellate sturgeon (Acipenser stellatus)

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    The effects of creosote on stellate sturgeon (Acipenser stellatus) juveniles each weighing 3.6 ±1 grams was evaluated. Acute toxicity test was undertaken in static water quality at 22 degree C plus or minus 1 according to the OECD method at the Caspian Sea Ecology Institute in 2005. The effect was assessed based on the results of the acute toxicity test. For the test, the hematological and biochemical properties of one control and five experimental groups of the fish juveniles what were exposed to creosote were compared. The acute toxicity test lasting 96 h was performed in fully static water condition with aeration

    A comparative analysis of feeding habits of sturgeon fish in shallow coastal waters of Mazandaran and Golestan Provinces, south Caspian Sea

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    Feeding habits of different genera of 354 sturgeon specimens (Acipenser persicus, Acipenser nudiventris, Acipenser stellatus) were compared over the years 1999-2000 caught in the coastal waters less than 20 meters deep of Mazandaran and Golestan provinces, southern Caspian Sea. The caught specimens ranged 30-18cm in length. Overall, 16 families of food items were identified in the digestive system of the sturgeon specimens, of which 11 belonged to macro-benthos. The sturgeon fishes preyed on food items composed of Annelids 50.8%, Amphipoda 41.5%, small fish 4.8%, Decapoda 2% and Bivalvia 0.9%. Fish specimens shorter than 40 cm were mostly found feeding on shrimps, polychaets and gamarids. The 41-80cm length class mostly fed on shrimps, gamarids, polychaets, bivalves and smaller fish. Sturgeons longer than 80cm fed mostly on shrimps and smaller fish. Average fat coefficient for Acipenser stellatus was 0.43. A. persicus showed a fat coefficient 0.63 while that of the A. nudiventris was 0.97. Average stomach fullness was 8.3, for Acipenser stellatus, 100 for A. nudiventris and 165 for A. persicus. We found a similar diet between group one fish less than 40 cm long and group two with fish in the length class 41 to 80cm (r=0.7)

    Some hematological and biochemical changes in blood serum of Grass carp (Ctenopharyngodon idella) vaccinated with Aeromonas hydrophila following exposure to sublethal concentration of diazinon

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    .Diazinon is commonly used for pest control in the agricultural fields in north of Iran. This study was conducted to determine the chronic toxicity of organophosphorous pesticide (Diazinon) in vaccinated fish and its effects on some hematological parameters and biochemical blood plasma profiles of Grass Carp (Ctenopharyngodon idella).This experiment was carried out in three groups. The first group was vaccinated and exposed to diazinon (group A) while the second group was vaccinated and bathed with PBS bath (group B). The remaining fish were used as unvaccinated fish and were kept in clean water separately (group C). Diazinon was applied at concentrations of 2 mg/L for 12 hours since the experiments were initiated. The experimental groups(A and B) showed significantly lower values (p < 0.05) of erythrocyte count, haemoglobin content, haematocrit, leucocytes, Lymphocyte, myelocyte and monocyte, as well as in alkaline phosphatases, alanine aminotransferase, aspartate aminotransferase and, lactate dehydrogenase compared to the control group(C). Values of MCV, MCH and MCHC of experimental species (A and B) were compared to the control group(C). The results of examinations of the biochemical blood plasma profile indicate a marked neurotoxic effect of diazinon in fishes. Changes in values of both erythrocyte and leukocyte profile after exposure to diazinon-based preparation may be referred to disruption of haematopoiesis as well as to a decrease on non-specific immunity of the fis

    Age, sex ratio, spawning season, gonadosomatic index, and fecundity of Cobitis faridpaki (Actinopterygii, Cobitidae) from the Siahrud River in the southeastern Caspian Sea basin

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    Cobitis faridpaki Cobitis faridpaki (Mousavi-Sabet, Vasil'eva, Vatandoust and Vasil'ev, 2011) is found in streams of the Siahrud River in the southeastern Caspian Sea basin, and this is the first report on reproductive parameters of the newly described endemic loach. Reproductive conditions are key parameters of fish populations, and their assessment is very important for endemic fishes. To study reproduction biology of this fish, sampling was done at monthly intervals throughout the year and 258 individuals of Cobitis faridpaki, were caught from Siahrud River in the southeastern Caspian Sea basin, in the north of Iran. Age, sex ratio, fecundity, oocytes diameter and gonadosomatic index were estimated. A regression analysis was used to find relationships between fecundity and fish size (length and weight), gonad weight and age. Sex ratio differed significantly from unity and was biased to females. The mature females and males were longer than 40 and 30 mm in total length, and +2 and +1 in age, respectively. The average egg diameter was 0.578 mm. Spawning took place from beginning of May to late July when water temperature was between 19.4 to 25.1 °C. Average GSI value at the beginning of the reproduction period was 9.12% and ranged between 2% to 20% in ripe mature females. The averages of absolute and relative fecundity were calculated as 1366 and 508, respectively. The absolute fecundity was significantly related to body weight and gonad weight. Based on the pattern of gonadosomatic index, it was concluded that this fish has a prolonged active reproduction period, which is a type of adaptation of short-lived small fishes to environmental conditions

    Exciton Spin Hall Effect In Arc-Shaped Strained WSe<sub>2</sub>

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    Generating a pure spin current using electrons, which have degrees of freedom beyond spin, such as electric charge and valley index, presents challenges. In response, we propose a novel mechanism based on intervalley exciton dynamics in {\em arc-shaped} strained transition metal dichalcogenides (TMDs) to achieve the {\em exciton spin Hall effect} in an electrically insulating regime, without the need for an external electric field. The interplay between strain gradients and strain-induced pseudomagnetic fields results in a net Lorentz force on long-lived intervalley excitons in WSe2_2, carrying non-zero spin angular momentum. This process generates an exciton-mediated pure spin Hall current, resulting in opposite-sign spin accumulations and local magnetization on the two sides of the single-layer arc-shaped TMD. We demonstrate that the magnetic field induced by spin accumulation, at approximately mT\sim {\rm mT}, can be detected using techniques such as superconducting quantum interference magnetometry or spatially-resolved magneto-optical Faraday and Kerr rotations

    Device-induced perforation of right atrium following interventional closure of Atrial Septal Defect (ASD)

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    This is a case presentation of a 26-year-old woman with a moderate-sized atrial septal secundum defect (17mm) who underwent catheterism, during which an Amplatzer Septal Occluder number 26 was inserted successfully. On the second postoperative day, she deteriorated and a clinical examination showed a typical tamponade. After a percutaneous aspiration of the pericardial cavity and transient improvement in vital signs, a pig-tail catheter was inserted percutaneously emergently, and the patient was transferred to the operating room in a preshock state. During the operation, an active bleeding point in the superoanterior aspect of the right atrium near the aortic root was detected, which was repaired by direct suture and pericardial patch reinforcement. The Amplatzer device was removed and the atrial septal defect was repaired with a pericardial patch. A lethal complication of the interventional closure of atrial septal defect, properly treated by an emergent intervention and operation, is presented and discussed herein

    On characterisations of the input to state stability properties for conformable fractional order bilinear systems

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    This paper proposes for the first time the theoretical requirements that a fractional-order bilinear system with conformable derivative has to fulfil in order to satisfy different input-to-state stability (ISS) properties. Variants of ISS, namely ISS itself, integral ISS, exponential integral ISS, small-gain ISS, and strong integral ISS for the general class of conformable fractional-order bilinear systems are investigated providing a set of necessary and sufficient conditions for their existence and then compared. Finally, the correctness of the obtained theoretical results is verified by numerical&nbsp;example

    Interaction between domperidone and ketoconazole : toward prediction of consequent QTc prolongation Using purely "In vitro" information

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    We aimed to investigate the application of combined mechanistic pharmacokinetic (PK) and pharmacodynamic (PD) modeling and simulation in predicting the domperidone (DOM) triggered pseudo-electrocardiogram modification in the presence of a CYP3A inhibitor, ketoconazole (KETO), using in vitro–in vivo extrapolation. In vitro metabolic and inhibitory data were incorporated into physiologically based pharmacokinetic (PBPK) models within Simcyp to simulate time course of plasma DOM and KETO concentrations when administered alone or in combination with KETO (DOM+KETO). Simulated DOM concentrations in plasma were used to predict changes in gender-specific QTcF (Fridericia correction) intervals within the Cardiac Safety Simulator platform taking into consideration DOM, KETO, and DOM+KETO triggered inhibition of multiple ionic currents in population. Combination of in vitro–in vivo extrapolation, PBPK, and systems pharmacology of electric currents in the heart was able to predict the direction and magnitude of PK and PD changes under coadministration of the two drugs although some disparities were detected
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