524 research outputs found

    Thin-Film LSCs Based on PMMA Nanohybrid Coatings: Device Optimization and Outdoor Performance

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    This study concerns the design optimization of thin-film luminescent solar concentrators (TLSCs) based on polymethylmethacrylate (PMMA)/silica nanohybrid films doped with coumarin dyestuffs specialized in coloring plastics. Two designs of TLSCs had been prepared and characterized. The first consists of a transparent nanohybrid layer coated on a fluorescent PMMA substrate. The second design is the ordinary configuration in which fluorescent nanohybrid layer is coated on a transparent PMMA substrate. The investigation of the spectral properties and efficiency parameters recommended the best solar energy conversion efficiency for the second design. The outdoor performance of optimized TLSC was also evaluated under clear sky conditions of Riyadh city, and the hourly values of the optical efficiency, ηopt, were calculated for one year. The best performance was achieved in summer since the short circuit current for PV cell was doubled after being attached to TLSC and the value of ηopt reached 40% which is higher than other values recorded before due to the abundant solar energy potential in the Arabian Peninsula

    Viral respiratory infections at the Hajj: comparison between UK and Saudi pilgrims

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    ABSTRACTA high incidence of respiratory infection, including influenza, has been reported at the Hajj in Mecca, Saudi Arabia. Reported rates of influenza have been higher among UK than among domestic pilgrims, but this could be explained by methodological differences among studies. Accordingly, the present study compared the frequencies of respiratory viruses among UK and Saudi pilgrims using the same study design. Pilgrims with upper respiratory tract symptoms were recruited from Mecca and the neighbouring valley Mina during the Hajj 2006. Nasal swabs were used for point-of-care influenza testing and real-time RT-PCR (rtRT-PCR) tests for influenza virus, rhinovirus, parainfluenza virus, adenovirus, human metapneumovirus and respiratory syncytial virus. Of 260 pilgrims investigated, 150 were from the UK and 110 were Saudi; of these, 38 (25%) UK pilgrims and 14 (13%) Saudi pilgrims had respiratory infections detectable by rtRT-PCR (p 0.01). In the UK group, there were 19 (13%) cases of rhinovirus infection, 15 (10%) cases of influenza virus infection, two (1%) cases of dual infections with influenza virus and rhinovirus, one (3%) case of parainfluenza virus infection, and one (1%) case of respiratory syncytial virus infection. Fifty-six (37%) UK pilgrims had been vaccinated against influenza virus, with the rates of influenza in the vaccinated and unvaccinated group being 7% and 14%, respectively (p 0.19). In the Saudi group, there were three (3%) cases of rhinovirus infection and 11 (10%) cases of influenza. Only four (4%) Saudi pilgrims had been vaccinated against influenza virus, and none of these was infected with influenza virus. Overall, a significantly higher proportion of the UK pilgrims had detectable respiratory infections (25% vs. 13%, p 0.01). Influenza rates were similar in both groups, but the reported rates of influenza vaccination differed

    Influenza and respiratory syncytial virus infections in British Hajj pilgrims

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    Viral respiratory infections including influenza and respiratory syncytial virus (RSV) have been reported during the Hajj among international pilgrims. To help establish the burden of these infections at the Hajj, we set up a study to confirm these diagnoses in symptomatic British pilgrims who attended the 2005 Hajj. UK pilgrims with symptoms of upper respiratory tract infection (URTI) were invited to participate; after taking medical history, nasal swabs were collected for point-of-care testing (PoCT) of influenza and for subsequent PCR analysis for influenza and RSV. Of the 205 patients recruited, 37 (18%) were positive for either influenza or RSV. Influenza A (H3) accounted for 54% (20/37) of the virus-positive samples, followed by RSV 24% (9/37), influenza B 19% (7/37), and influenza A (H1) 3% (1/37). Of the influenza-positive cases, 29% (8/28) had recently had a flu immunisation. Influenza was more common in those who gave a history of contact with a pilgrim with a respiratory illness than those who did not (17 versus 9%). The overall rate of RSV was 4% (9/202). This study confirms that influenza and RSV cause acute respiratory infections in British Hajj pilgrims. Continuing surveillance and a programme of interventions to contain the spread of infection are needed at the Hajj, particularly when the world is preparing for an influenza pandemic

    Molecular detection of Leishmania species in Sand Flies by PCR-RFLP technique in refugee camps

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    ABSTRACT Leishmaniasis is one of the most important health dilemmas facing the World Health Organization (WHO), due to it being widespread and the great diversity of sand flies that transmit it. This study aimed to detect the presence of Leishmania parasites in the sand flies spread in Refugee camps by PCR- RLFP technique. A total of 437 sandflies were collected and classified into two species Phlebotomus papatasi and Phlebotomus sergenti. DNA was extracted from the female fly species, then the PCR reaction was amplified by two primers (LITSR, L5.8S) that transcribed a partial internal transcribed spacer (ITS)-1 gene for Leishmania parasite with a length of 320 bp. PCR showed the presence of Leishmania DNA in females of both P. papatasi (10%) and P. sergenti (20%). To determine Leishmania species transmitted by the two previous fly species, the RFLP-PCR technique was performed by the HaeIII enzyme for Leishmania DNA extracted from them. RFLP-PCR showed that P. papatasi females transmitted Leishmania major and P. sergenti females transmitted Leishmania tropica in Refugee camps. It could be concluded that leishmaniasis is widely distributed in Refugee camps due to the presence of its vector

    The ligational behavior of a phenolic quinolyl hydrazone towards copper(II)- ions

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    <p>Abstract</p> <p>Background</p> <p>The heterocyclic hydrazones constitute an important class of biologically active drug molecules. The hydrazones have also been used as herbicides, insecticides, nematocides, redenticides, and plant growth regulators as well as plasticizers and stabilizers for polymers. The importance of the phenolic quinolyl hydrazones arises from incorporating the quinoline ring with the phenolic compound; 2,4-dihydroxy benzaldehyde. Quinoline ring has therapeutic and biological activities whereas, phenols have antiseptic and disinfectants activities and are used in the preparation of dyes, bakelite and drugs. The present study is planned to check the effect of the counter anions on the type and geometry of the isolated copper(II)- complexes as well as the ligational behavior of the phenolic hydrazone; 4-[(2-(4,8-dimethylquinolin-2-yl)hydrazono)methyl] benzene-1,3-diol; (H<sub>2</sub>L).</p> <p>Results</p> <p>A phenolic quinolyl hydrazone (H<sub>2</sub>L) was allowed to react with various copper(II)- salts (Cl‾, Br‾, NO<sub>3</sub>‾, ClO<sub>4</sub>‾, AcO‾, SO<sub>4</sub><sup>2-</sup>). The reactions afforded dimeric complexes (ClO<sub>4</sub>‾, AcO‾ ), a binuclear complex (NO<sub>3</sub>‾ ) and mononuclear complexes (the others; Cl‾, Br‾, SO<sub>4</sub><sup>2-</sup>). The isolated copper(II)- complexes have octahedral, square pyramid and square planar geometries. Also, they reflect the strong coordinating ability of NO<sub>3</sub>‾, Cl‾, Br‾, AcO‾ and SO<sub>4</sub><sup>2- </sup>anions. Depending on the type of the anion, the ligand showed three different modes of bonding <it>viz</it>. (NN)<sup>0 </sup>for the mononuclear complexes (<b>3, 4, 6</b>), (NO)<sup>- </sup>with O- bridging for the dimeric complexes (<b>1, 5</b>) and a mixed mode [(NN)<sup>0 </sup>+ (NO)<sup>- </sup>with O- bridging] for the binuclear nitrato- complex (<b>2</b>).</p> <p>Conclusion</p> <p>The ligational behavior of the phenolic hydrazone (H<sub>2</sub>L) is highly affected by the type of the anion. The isolated copper(II)- complexes reflect the strong coordinating power of the SO<sub>4</sub><sup>2-</sup>, AcO‾, Br‾, Cl‾ and NO<sub>3</sub>‾ anions. Also, they reflect the structural diversity (octahedral, square pyramid and square planar) depending on the type of the counter anion.</p

    Pharmacological screening of Viola Odorata L. for memory-enhancing effect via modulation of oxidative stress and inflammatory biomarkers

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    Purpose: Alzheimer disease (AD) is a progressive neurodegenerative disorder that is caused by neuroinflammation and oxidative stress. The present study aimed to characterize and then investigate the memory-enhancing potential of Viola odorata methanolic extract in lipopolysaccharide (LPS)–treated mice. Methods: V. odorata characterization was done by using the GCMS technique. Neuroinflammation was induced by the intracerebroventricular administration of LPS at a dose of 12 μg. Animals were divided randomly into six groups (n 10). Group I was normal control, which was given vehicle. Group II was disease control, which received LPS (12 μg) via the intracerebroventricular route. Group III was standard, which was administered with donepezil (3 μg) orally for 21 days. Groups IV–VI were the treatment groups, which were administered with the extract at 100, 200, and 400 mg/kg dose levels orally respectively for 21 days. Groups III–VI received LPS (12 μg) on the first day along with their treatments. During the treatment, the animals were assessed for memory retention by employing different behavioral paradigms namely elevated plus maze, passive avoidance, foot shock and open field. Various mediators [endogenous antioxidants, neurotransmitters, and acetylcholinesterase (AChE)] involved in the pathogenesis of AD were quantified by using the UV spectrophotometric method. Results: Extract-treated groups showed a remarkable improvement in cognitive impairment in all behavioral paradigms. Oxidative stress biomarkers, that is, superoxide dismutase, catalase, and glutathione were raised dose-dependently in the treatment groups with a dose-dependent decrease in the malonaldehyde and AChE levels in the brains of the treated animals. The treatment groups showed decreased levels of inflammatory biomarkers, that is, tumor necrosis factor–alpha, nuclear factor kappa light-chain enhancer of activated β-cells, and cyclo-oxygenase, which supports the therapeutic effectiveness of the treatment. Conclusion: Based on behavioral, oxidative stress biomarker, and neuroinflammatory data, it is concluded that V. odorata possesses memory-enhancing activity and may prove a beneficial role in the management of AD.peer-reviewe

    A New Chaotic Map with Dynamic Analysis and Encryption Application in Internet of Health Things

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    © 2013 IEEE. In this paper, we report an effective cryptosystem aimed at securing the transmission of medical images in an Internet of Healthcare Things (IoHT) environment. This contribution investigates the dynamics of a 2-D trigonometric map designed using some well-known maps: Logistic-sine-cosine maps. Stability analysis reveals that the map has an infinite number of solutions. Lyapunov exponent, bifurcation diagram, and phase portrait are used to demonstrate the complex dynamic of the map. The sequences of the map are utilized to construct a robust cryptosystem. First, three sets of key streams are generated from the newly designed trigonometric map and are used jointly with the image components (R, G, B) for hamming distance calculation. The output distance-vector, corresponding to each component, is then Bit-XORed with each of the key streams. The output is saved for further processing. The decomposed components are again Bit-XORed with key streams to produce an output, which is then fed into the conditional shift algorithm. The Mandelbrot Set is used as the input to the conditional shift algorithm so that the algorithm efficiently applies confusion operation (complete shuffling of pixels). The resultant shuffled vectors are then Bit-XORed (Diffusion) with the saved outputs from the early stage, and eventually, the image vectors are combined to produce the encrypted image. Performance analyses of the proposed cryptosystem indicate high security and can be effectively incorporated in an IoHT framework for secure medical image transmission

    Breast Cancer Diagnosis and Survival Prediction Using JNN

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    Abstract: Breast cancer is reported to be the most common cancer type among women worldwide and it is the second highest women fatality rate amongst all cancer types. Notwithstanding all the progresses made in prevention and early intervention, early prognosis and survival prediction rates are still not sufficient. In this paper, we propose an ANN model which outperforms all the previous supervised learning methods by reaching 99.57 in terms of accuracy in Wisconsin Breast Cancer dataset. Experimental results on Haberman’s Breast Cancer Survival dataset show the superiority of proposed method by reaching 88.24 % in terms of accuracy. The results are the best reported ones obtained from Artificial Neural Network using JNN environment without any preprocessing of the dataset

    The ligational behavior of an isatinic quinolyl hydrazone towards copper(II)- ions

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    <p>Abstract</p> <p>Background</p> <p>The importance of the isatinic quinolyl hydrazones arises from incorporating the quinoline ring with the indole ring. Quinoline ring has therapeutic and biological activities whereas, the indole ring occurs in Jasmine flowers and Orange blossoms. As a ligand, the isatin moiety is potentially ambidentate and can coordinate the metal ions either through its lactam or lactim forms. In a previous study, the ligational behavior of a phenolic quinolyl hydrazone towards copper(II)- ions has been studied. As continuation of our interest, the present study is planned to check the ligational behavior of an isatinic quinolyl hydrazone.</p> <p>Results</p> <p>New homo- and heteroleptic copper(II)- complexes were obtained from the reaction of an isatinic quinolyl hydrazone (HL) with several copper(II)- salts <it>viz. </it>Clˉ, Brˉ, NO<sub>3</sub>ˉ, ClO<sub>4</sub><sup>-</sup>, SO<sub>4</sub><sup>2- </sup>and AcO<sup>-</sup>. The obtained complexes have O<sub>h</sub>, T<sub>d </sub>and D<sub>4h</sub>- symmetry and fulfill the strong coordinating ability of Clˉ, Brˉ, NO<sub>3</sub>ˉ and SO<sub>4</sub><sup>2- </sup>anions. Depending on the type of the anion, the ligand coordinates the copper(II)- ions either through its lactam (NO<sub>3</sub>ˉ and ClO<sub>4</sub><sup>-</sup>) or lactim (the others) forms.</p> <p>Conclusion</p> <p>The effect of anion for the same metal ion is obvious from either the geometry of the isolated complexes (O<sub>h</sub>, T<sub>d </sub>and D<sub>4h</sub>) or the various modes of bonding. Also, the obtained complexes fulfill the strong coordinating ability of Clˉ, Brˉ, NO<sub>3</sub>ˉ and SO<sub>4</sub><sup>2- </sup>anions in consistency with the donor ability of the anions. In case of copper(II)- acetate, a unique homoleptic complex (<b>5</b>) was obtained in which the AcO<sup>- </sup>anion acts as a base enough to quantitatively deprotonate the hydrazone. The isatinic hydrazone uses its lactim form in most complexes.</p

    State sampling dependence of the Hopfield network inference

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    The fully connected Hopfield network is inferred based on observed magnetizations and pairwise correlations. We present the system in the glassy phase with low temperature and high memory load. We find that the inference error is very sensitive to the form of state sampling. When a single state is sampled to compute magnetizations and correlations, the inference error is almost indistinguishable irrespective of the sampled state. However, the error can be greatly reduced if the data is collected with state transitions. Our result holds for different disorder samples and accounts for the previously observed large fluctuations of inference error at low temperatures.Comment: 4 pages, 1 figure, further discussions added and relevant references adde
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