708 research outputs found

    Microstrip transmission line theory, characteristics, and components

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    Microwave-Assisted Synthesis of Some 1H-1,2,4-Triazol-3-one Derivatives

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    4-Amino-5-(methyl/ethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one were synthesized from the reaction of (methyl/ethyl)-ester ethoxycarbonyl hydrazone with hydrazine hydrate and then, converted to corresponding Schiff bases using 9H-fluorene- 3-carbaldehyde. Ester, hydrazide and oxadiazole derivatives were synthesized starting from Schiff bases in three steps. All reactions occurred under conventional conditions and microwave irradiation. The obtained results were compared.KEYWORDS Triazole, oxadiazole, hydrazine hydrate, microwave irradiation

    PHYTOCHEMICAL STUDY AND THE ANTIPROLIFERATIVE ACTIVITY OF INULA VULGARIS SPECIES GROWN IN LEBANON

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    Objective: Cancer represents the second leading cause of death after stroke and heart diseases. Plant extracts have long been used in traditional medicine for the prevention and treatment of many illnesses, including some types of cancer. The aim of this study was to evaluate the antiproliferative effects of ethyl acetate fractions of two Lebanese herbs: Inula viscosa (I. vis) and Inula vulgaris (I. vul).Methods: Plants were extracted with ethanol followed by ethyl acetate, then dried and tested on three cell lines including CaCO2, HepG2, and MCF7, to check for their viability and antiproliferative activity, using trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Proton (1H) and carbon (13C) nuclear magnetic resonance spectrometry (NMR) were used to identify the compounds that have been isolated from both Inula species.Results: The current findings were consistent for both trypan blue and MTT assays. The results showed that the most potent effect for I. vul was HepG2 (IC50 20 µg/ml, 27 µg/ml), and for I. vis on MCF7 (9 µg/ml, 15 µg/ml) and CaCO2 (12 µg/ml, 22 µg/ml) in the two mentioned assays respectively. However, insignificant differences were observed among the studied plants for each of the evaluated cells indicating comparable potencies. Quercetin, quercetin glycoside, and epicatechin derivatives were isolated by fractionation on column chromatography and identified using NMR spectroscopy.Conclusion: The antiproliferative activities of the two plants could be related to their content that is significant for high levels of secondary metabolites. The identification of those compounds is necessary to establish a relationship between their chemical structures and their activities

    Mucoid Cyst of The Penile Skin: A Rare Entity

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    A 9-year old male patient was admitted to our clinic for circumcision. Physical examination revealed a mass in the prepuce. After excision of the mass, histopathological examination was consistent with a mucoid cyst of the penile skin, which has been rarely reported. Pathologists and clinicians dealing with genitourinary system pathology should be familiar with this rarely encountered entity.Key Words: Mucoid cyst, penile ski

    Characterization of a ballistic supermirror neutron guide

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    We describe the beam characteristics of the first ballistic supermirror neutron guide H113 that feeds the neutron user facility for particle physics PF1B of the Institute Laue-Langevin, Grenoble (ILL). At present, the neutron capture flux density of H113 at its 20x6cm2 exit window is 1.35x10^10/cm^2/s, and will soon be raised to above 2x10^10/cm^2/s. Beam divergence is no larger than beam divergence from a conventional Ni coated guide. A model is developed that permits rapid calculation of beam profiles and absolute event rates from such a beam. We propose a procedure that permits inter-comparability of the main features of beams emitted from ballistic or conventional neutron guides.Comment: 15 pages, 11 figures, to be submitted to Nuclear Instruments and Methods

    Molecular engineering of organic semiconductors enables noble metal-comparable SERS enhancement and sensitivity

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    Nanostructured molecular semiconductor films are promising Surface-Enhanced Raman Spectroscopy (SERS) platforms for both fundamental and technological research. Here, we report that a nanostructured film of the small molecule DFP-4T, consisting of a fully π-conjugated diperfluorophenyl-substituted quaterthiophene structure, demonstrates a very large Raman enhancement factor (>105) and a low limit of detection (10-9 M) for the methylene blue probe molecule. This data is comparable to those reported for the best inorganic semiconductor- and even intrinsic plasmonic metal-based SERS platforms. Photoluminescence spectroscopy and computational analysis suggest that both charge-transfer energy and effective molecular interactions, leading to a small but non-zero oscillator strength in the charge-transfer state between the organic semiconductor film and the analyte molecule, are required to achieve large SERS enhancement factors and high molecular sensitivities in these systems. Our results provide not only a considerable experimental advancement in organic SERS figure-of-merits but also a guidance for the molecular design of more sensitive SERS systems

    Size-controlled conformal nanofabrication of biotemplated three-dimensional TiO2 and ZnO nanonetworks

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    Cataloged from PDF version of article.A solvent-free fabrication of TiO2 and ZnO nanonetworks is demonstrated by using supramolecular nanotemplates with high coating conformity, uniformity, and atomic scale size control. Deposition of TiO2 and ZnO on three-dimensional nanofibrous network template is accomplished. Ultrafine control over nanotube diameter allows robust and systematic evaluation of the electrochemical properties of TiO2 and ZnO nanonetworks in terms of size-function relationship. We observe hypsochromic shift in UV absorbance maxima correlated with decrease in wall thickness of the nanotubes. Photocatalytic activities of anatase TiO2 and hexagonal wurtzite ZnO nanonetworks are found to be dependent on both the wall thickness and total surface area per unit of mass. Wall thickness has effect on photoexcitation properties of both TiO2 and ZnO due to band gap energies and total surface area per unit of mass. The present work is a successful example that concentrates on nanofabrication of intact three-dimensional semiconductor nanonetworks with controlled band gap energies

    How K-12 students search for learning? Analysis of an educational search engine log

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    In this study, we analyze an educational search engine log for shedding light on K-12 students' search behavior in a learning environment. We specially focus on query, session, user and click characteristics and compare the trends to the findings in the literature for general web search engines. Our analysis helps understanding how students search with the purpose of learning in an educational vertical, and reveals new directions to improve the search performance in the education domain. Copyright 2014 ACM

    The challenge to verify ceramide's role of apoptosis induction in human cardiomyocytes - a pilot study

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    <p>Abstract</p> <p>Background</p> <p>Cardioplegia and reperfusion of the myocardium may be associated with cardiomyocyte apoptosis and subsequent myocardial injury. In order to establish a pharmacological strategy for the prevention of these events, this study aimed to verify the reliability of our human cardiac model and to evaluate the pro-apoptotic properties of the sphingolipid second messenger ceramide and the anti-apoptotic properties of the acid sphingomyelinase inhibitor amitryptiline during simulated cardioplegia and reperfusion ex vivo.</p> <p>Methods</p> <p>Cardiac biopsies were retrieved from the right auricle of patients undergoing elective CABG before induction of cardiopulmonary bypass. Biopsies were exposed to <it>ex vivo </it>conditions of varying periods of cp/rep (30/10, 60/20, 120/40 min). Groups: I (untreated control, n = 10), II (treated control cp/rep, n = 10), III (cp/rep + ceramide, n = 10), IV (cp/rep + amitryptiline, n = 10) and V (cp/rep + ceramide + amitryptiline, n = 10). For detection of apoptosis anti-activated-caspase-3 and PARP-1 cleavage immunostaining were employed.</p> <p>Results</p> <p>In group I the percentage of apoptotic cardiomyocytes was significantly (p < 0.05) low if compared to group II revealing a time-dependent increase. In group III ceramid increased and in group IV amitryptiline inhibited apoptosis significantly (p < 0.05). In contrast in group V, under the influence of ceramide and amitryptiline the induction of apoptosis was partially suppressed.</p> <p>Conclusion</p> <p>Ceramid induces and amitryptiline suppresses apoptosis significantly in our ex vivo setting. This finding warrants further studies aiming to evaluate potential beneficial effects of selective inhibition of apoptosis inducing mediators on the suppression of ischemia/reperfusion injury in clinical settings.</p
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