2,357 research outputs found

    Optička svojstva tankih slojeva bismut sulfida Bi2S3

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    Thin films of bismuth sulfide (Bi2S3) were grown by two deposition techniques, by thermal evaporation and by chemical deposition. The thermally deposited reactions consisted in depositing the individual elements, namely bismuth and sulfur, sequentially from a tungsten boat source and allowing the layers to interdiffuse to form the compound during the heat-treatment. The chemical deposition was based on the reaction between the triethanolamine compex of Bi3+ ions and thiourea in basic media. Scanning electron microscope and X-ray diffraction analysis were made on as-deposited and on annealed films to determine their structure. The different electronic transitions and the optical constants are determined from the transmision and reflection data of these thin films for normal incidence. The optical gaps of Bi2S3 films show a remarkable dependence on the preparation method.Tanki su slojevi bismut sulfida (Bi2S3) načinjeni dvjema metodama, vakuumskim naparavanjem i kemijskim taloženjem. Ti su se slojevi istraživali sustavno-pretražnom elektronskom mikroskopijom i difrakcijom rentgenskog zračenja, prije i nakon termičkog opuštanja. Našao se je niz elektronskih prijelaza i odredile se optičke konstante na osnovi transmisijskih i refleksijskih podataka za okomitu upadnu svjetlost. Optički procijepi Bi2S3 pokazuju priličnu ovisnost o metodi pripremanja

    Interaction of CO molecules with (Cu , Ag and Au) deposited on regular and defective MgO and BaO(001) surfaces: Density functional calculations

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    The adsorption properties and characteristics of CO on Cu, Ag and Au atoms deposited on various sites of the alkaline earth oxide MgO and BaO. The three members of morphological irregularities, terrace, edge, and oxygen terminated corner of MgO and BaO (001) surface have been studied by means of density functional calculations and embedded cluster model. The examined clusters were embedded in the simulated Coulomb fields that closely approximate the Madelung fields of the host surfaces. The  adsorption  properties  of  CO  have  been  analyzed  with reference  to  the  nature  of  the  oxide  support,  pairwise  and  non-pairwise  ..........Please read the full paper

    Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer

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    Cancer was recently annexed to diabetic complications. Furthermore, recent studies suggest that cancer can increase the risk of diabetes. Consequently, diabetes and cancer share many risk factors, but the cellular and molecular pathways correlating diabetes and colon and rectal cancer (CRC) remain far from understood. In this study, we assess the effect of hyperglycemia on cancer cell aggressiveness in human colon epithelial adenocarcinoma cells in vitro and in an experimental animal model of CRC. Our results show that Nox (NADPH oxidase enzyme) 4-induced reactive oxygen species (ROS) production is deregulated in both diabetes and CRC. This is paralleled by inactivation of the AMPK and activation of the mammalian target of rapamycin (mTOR) C1 signaling pathways, resulting in 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) accumulation, induction of DNA damage, and exacerbation of cancer cell aggressiveness, thus contributing to the genomic instability and predisposition to increased tumorigenesis in the diabetic milieu. Pharmacologic activation of AMPK, inhibition of mTORC1, or blockade of Nox4 reduce ROS production, restore the homeostatic signaling of 8-oxoguanine DNA glycosylase/8-oxodG, and lessen the progression of CRC malignancy in a diabetic milieu. Taken together, our results identify the AMPK/mTORC1/Nox4 signaling axis as a molecular switch correlating diabetes and CRC. Modulating this pathway may be a strategic target of therapeutic potential aimed at reversing or slowing the progression of CRC in patients with or without diabetes.-Mroueh, F. M., Noureldein, M., Zeidan, Y. H., Boutary, S., Irani, S. A. M., Eid, S., Haddad, M., Barakat, R., Harb, F., Costantine, J., Kanj, R., Sauleau, E.-A., Ouhtit, A., Azar, S. T., Eid, A. H., Eid, A. A. Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer.Scopu

    A Cross-Cultural Systematic Review of Vitamin D Deficiency in Women

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    Vitamin D deficiency has been reported in several cultures and regions, including the Middle East, North Europe, and Australia. In this review, we summarize and discuss existing studies on factors underlying vitamin D deficiency across different regions. In particular, we explain key roles played by lifestyle, including sun exposure, season change, diet, and clothing (concealing vs. non-concealing) as factors leading to vitamin D deficiency. We further discuss gender differences in vitamin D levels and, the impact of vitamin D supplements on cognition. The introductory section of this paper focuses on introducing vitamin D deficiency and highlighting the prevalence of vitamin D deficiency in Eastern countries. Here, we also provide a comparative literature analysis not only based on Eastern and Western countries but also compare the prevalence of vitamin D deficiency between males and females. Our review provides key information on potential life changes that help increase vitamin D and protect against the development of several disorders

    Mesoscopic open-eye core–shell spheroid carved anode/cathode electrodes for fully reversible and dynamic lithium-ion battery models

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    We report on the key influence of mesoscopic super-open-eye core–shell spheroids of TiO2- and LiFePO4-wrapped nanocarbon carved anode/cathode electrodes with uniform interior accommodation/storage pockets for the creation of fully reversible and dynamic Li-ion power battery (LIB) models. The mesoscopic core–shell anode/cathode electrodes provide potential half- and full-cell LIB-CR2032 configuration designs, and large-scale pouch models. In these variable mesoscopic LIB models, the broad-free-access and large-open-eye like gate-in-transport surfaces featured electrodes are key factors of built-in LIBs with excellent charge/discharge capacity, energy density performances, and outstanding cycling stability. Mesoscopic open-eye spheroid full-LIB-CR2032 configuration models retain 77.8% of the 1st cycle discharge specific capacity of 168.68 mA h g−1 after multiple cycling (i.e., 1st to 2000th cycles), efficient coulombic performance of approximately 99.6% at 0.1C, and high specific energy density battery of approximately 165.66 W h kg−1 at 0.1C. Furthermore, we have built a dynamic, super-open-mesoeye pouch LIB model using dense packing sets that are technically significant to meet the tradeoff requirements and long-term driving range of electric vehicles (EVs). The full-pouch package LIB models retain a powerful gate-in-transport system for heavy loaded electron/Li+ ion storage, diffusion, and truck movement through open-ended out/in and then up/downward eye circular/curvy folds, thereby leading to substantial durability, and remarkable electrochemical performances even after long-life charge/discharge cycling

    Evolution of low-mass metal-free stars including effects of diffusion and external pollution

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    We investigate the evolution of low-mass metal-free Population III stars. Emphasis is laid upon the question of internal and external sources for CNO-elements, which - if present in sufficient amounts in the hydrogen-burning regions - lead to a strong modification of the stars' evolutionary behavior. For the production of carbon due to nuclear processes inside the stars, we use an extended nuclear network, demonstrating that hot pp-chains do not suffice to produce enough carbon or are less effective than the triple3-alpha-process. As an external source of CNO-elements we test the efficiency of pollution by a nearby massive star combined with particle diffusion. For all cases investigated, the additional metals fail to reach nuclear burning regions before deep convection on the Red Giant Branch obliterates the previous evolution. The surface abundance history of the polluted Pop III stars is presented. The possibilities to discriminate between a Pop II and a polluted Pop III field star are also discussed.Comment: Accepted for publication in Ap

    Intra-articular dexmedetomidine with bupivacaine versus bupivacaine alone for postoperative analgesia after knee arthroscopy

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    Background: Optimal relief of pain after knee arthroscopy is essential for early rehabilitation and mobilisation and to minimise postoperative morbidity. This study’s aim was to assess dexmedetomidine as an additive to intra-articular (IA) bupivacaine in terms of analgesic duration and postoperative rescue analgesic consumption following arthroscopic knee surgery.Methods: A total of 70 patients, ASA physical status I and II, undergoing knee arthroscopy under general anaesthesia were enrolled in this double-blinded randomised controlled study, after Pan African Clinical Trial Registry (PACTR201507001048242) approval was obtained. Patients were randomly assigned into two groups; the bupivacaine group (B) received IA 19 ml bupivacaine 0.5% + 1 ml normal saline, bupivacaine dexmedetomidine group (BD) received IA injection of 19 ml bupivacaine 0.5% + dexmedetomidine 100 μg (1 ml). Postoperative visual analogue pain score (VAS), duration of analgesia and postoperative analgesic requirement were assessed.Results: VAS scores at rest and on mobilisation were significantly lower in the BD group at 4 h, 6 h and 8 h postoperatively in comparison with group B (p < 0.05). VAS scores were comparable between studied groups during the first 2 h, and at 12 h and 24 h postoperatively. Duration of analgesia was significantly longer in group BD (458.9 ± 93.5 min) than in the B group (229.1 ± 83.7 min) (p < 0.05). Postoperative analgesic consumption was lowered in the BD group compared with the B group (p < 0.05).Conclusions: Adding dexmedetomidine to IA bupivacaine after knee arthroscopy prolongs analgesic duration and decreases postoperative analgesic requirement.Keywords: arthroscopy, dexmedetomidine, intra-articular, postoperative pai

    Pastoralists do plan! Community-led land use planning in the pastoral areas of Ethiopia

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    This paper consolidates a set of case studies which document how pastoralists plan land and resource use in pastoral and agro-pastoral areas of Ethiopia. These case studies are drawn from the regional states of Afar, Somali, Southern Nations, Nationalities, and Peoples (SNNP), Oromia, and Gambella. They describe not only why, how, and when pastoralists plan, but also the management and governance structures that control planning processes and the later implementation of the plans. By doing this, the paper provides guidance on how best such planning processes can be supported, and how they can be integrated with and/or built on by other planning processes such as those led by government
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