119 research outputs found

    Synthesis and characterization of (Pani/n-si)solar cell

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    AbstractPolyaniline(PAni) doped with formic acid was synthesis by chemical polymerization method using ammonium persulphate as oxidizing agent. Polyaniline /n-silicon hetrojunction have been fabricated by spin coating of polyaniline onto n-type silicon substrates. I-V characteristic of these junction diode show rectifying behavior with rectifying ratio of about 100. The I-V characteristics of PAni/n-Si junction were measured at room temperature (303K) and after annulling at 363K. They are found to exhibit quality factors of 1.83 and 1.32, saturation current of 5x10-6A and 5x10-4A, and barrier heights of 0.73eV and 0.61eV respectively. The photovoltaic properties of this hybrid solar cell were studied in the dark and under illumination investigated hybrid and was found to deliver short circuit current density Jsc =45ΌA/cm2, open circuit voltage Voc = 400mV, and solar cell efficiency η =0.3% under AM 1.5 simulated solar light with the intensity of 100mW/cm2

    Multibiometric Identification System based on SVD and Wavelet Decomposition

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    Biometric systems refer to the systems used for human recognition based on their characteristics. These systems are widely used in security institutions and access control. In this work three biometric sources were used for identification purposes. Singular value decomposition (SVD) was employed as a tool for feature extraction and artificial neural network (ANN) was used as pattern recognition for the model. High accuracy was obtained from this work with 95% recognition rate

    A preliminary study on whether HbA1c levels can predict visual dependence for spatial orientation in asymptomatic Type 2 diabetic patients

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    Introduction: Diabetes-induced vestibular dysfunction has been commonly reported, and asymptomatic patients with type 2 diabetes display higher degrees of perceptual visual dependence for spatial orientation than healthy controls. This study aims to assess whether HbA1c can predict such visual dependence in the diabetic patients. Methods and Materials: Diabetic patients were divided into 2 groups: 22 subjects with “good” (HbA1c < 7%) and 25 with “poor” (HbA1c ≄ 7%) glycemic control. Otolithic vestibular function was tested using the computerized rod-and-frame test (CRFT) and results for the two diabetic groups were compared to 29 healthy controls. Results: When the frame was tilted, the diabetic group with “good” glycemic control had largest positioning errors, with a significant difference only in comparison to the control group. The “good” glycemic group exhibited larger degree of asymmetry under titled frame condition. Although HbA1c was not associated with vestibular asymmetry in any diabetic group, it was significantly associated with visual dependence in the “good” glycemic group. During frame tilts, 10 diabetic patients had positioning errors above the reference range of 3.3°, 8 of which belonged to the “good” glycemic diabetic group. Conclusions: Diabetes disease processes may affect vestibular symmetry during visuo-vestibular conflicts, even in asymptomatic diabetics within the recommended glycemic range. The weak correlations between HbA1c and CRFT parameters may indicate that HbA1c cannot fully predict visual dependence or asymmetry on the CRFT in patients with diabetes, and different glycemic disorders may affect vestibular dependent spatial orientation in diabetic patients

    $p+^{4,6,8}He elastic scattering at intermediate energies

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    Using a relativistic nuclear optical potential consisting of a Lorentz scalar, VsV_{s}, and the time-like component of a four-vector potential, V0V_{0}, we calculate elastic scattering differential cross sections and polarizations for p+4p+^{4}He at intermediate energies for which experimental data are available. We also calculate the differential cross sections and analyzing powers for p+6,8p+^{6,8}He at intermediate energies and compare with the few available experimental data.Comment: 09 pages, 04 figure

    Study on isolation improvement between closely packed patch antenna arrays based on fractal metamaterial electromagnetic bandgap structures

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    A decoupling metamaterial (MTM) configuration based on fractal electromagnetic bandgap (EMBG) structure is shown to significantly enhance isolation between transmitting and receiving antenna elements in a closely packed patch antenna array. The MTM-EMBG structure is cross-shaped assembly with fractal slots etched in each arm of the cross. The fractals are composed of four interconnected ‘Y-shaped’ slots that are separated with an inverted ‘T-shaped’ slot. MTM-EMBG structure is placed between the individual patch antennas in a 2×2 antenna array. Measured results show the average inter-element isolation improvement in the complete band of interest is 17 dB, 37 dB and 17 dB between radiation elements #1 & #2, #1 & #3, and #1 & #4, respectively. With the proposed method there is no need for metallic via-holes. The proposed array covers the frequency range of 8- 9.25 GHz for X-band applications, which corresponds to a fractional bandwidth of 14.5%. With the proposed method the edge-to-edge gap between the antenna can be reduced to 0.5λ0 with no degradation in the antenna’s radiation patterns. The gain of the antenna array varies between 4 dBi and 7 dBi. The proposed method is applicable for implementation of closely packed patch antenna arrays, e.g. multiple-input-multiple-output (MIMO) systems, and synthetic aperture radars (SAR)

    Evaluation of analogues of furan-amidines as inhibitors of NQO2

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    Inhibitors of the enzyme NQO2 (NRH: quinone oxidoreductase 2) are of potential use in cancer chemotherapy and malaria. We have previously reported that non-symmetrical furan amidines are potent inhibitors of NQO2 and here novel analogues are evaluated. The furan ring has been changed to other heterocycles (imidazole, N-methylimidazole, oxazole, thiophene) and the amidine group has been replaced with imidate, reversed amidine, N-arylamide and amidoxime to probe NQO2 activity, improve solubility and decrease basicity of the lead furan amidine. All compounds were fully characterised spectroscopically and the structure of the unexpected product N-hydroxy-4-(5-methyl-4-phenylfuran-2-yl)benzamidine was established by X-ray crystallography. The analogues were evaluated for inhibition of NQO2, which showed lower activity than the lead furan amidine. The observed structure-activity relationship for the furan-amidine series with NQO2 was rationalized by preliminary molecular docking and binding mode analysis. In addition, the oxazole-amidine analogue inhibited the growth of Plasmodium falciparum with an IC50 value of 0.3 ÎŒM

    Bilosomes as a promising nanoplatform for oral delivery of an alkaloid nutraceutical:improved pharmacokinetic profile and snowballed hypoglycemic effect in diabetic rats

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    Diabetes mellitus is a life-threatening metabolic disease. At the moment, there is no effective treatment available to combat it. In this study, we aimed to develop berberine-loaded bilosomes (BER-BLS) to boost the oral bioavailability and therapeutic efficacy of berberine, a natural antidiabetic medication. The BER-BLS was fabricated using a thin-film hydration strategy and optimized using a central composite design (face-centered). The average vesicle size, entrapment efficiency, and surface charge of the optimized BER-BLS preparation were 196.5 nm, 89.7%, (−) 36.4 mV, respectively. In addition, it exhibited higher stability and better-sustained release of berberine than the berberine solution (BER-SOL). BER-BLS and BER-SOL were administered to streptozocin-induced diabetic rats. The optimized BER-BLS formulation had a significant hypoglycemic impact, with a maximum blood glucose decrease of 41%, whereas BER-SOL only reduced blood glucose by 19%. Furthermore, the pharmacological effect of oral BER-BLS and BER-SOL corresponded to 99.3% and 31.7%, respectively, when compared to subcutaneous insulin (1 IU). A pharmacokinetic analysis found a 6.4-fold rise in the relative bioavailability of berberine in BER-BLS when compared to BER-SOL at a dosage of 100 mg/kg body weight. Histopathological investigation revealed that BER-BLS is suitable for oral administration. Our data demonstrate that BLS is a potential nanocarrier for berberine administration, enhancing its oral bioavailability and antidiabetic activity

    Prevalence of bacteriologically-confirmed pulmonary tuberculosis in urban Blantyre, Malawi 2019-20: substantial decline compared to 2013-14 national survey

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    Recent evidence shows rapidly changing tuberculosis (TB) epidemiology in Southern and Eastern Africa, with need for subdistrict prevalence estimates to guide targeted interventions. We conducted a pulmonary TB prevalence survey to estimate current TB burden in Blantyre city, Malawi. From May 2019 to March 2020, 115 households in middle/high-density residential Blantyre, were randomly-selected from each of 72 clusters. Consenting eligible participants (household residents ≄ 18 years) were interviewed, including for cough (any duration), and offered HIV testing and chest X-ray; participants with cough and/or abnormal X-ray provided two sputum samples for microscopy, Xpert MTB/Rif and mycobacterial culture. TB disease prevalence and risk factors for prevalent TB were calculated using complete-case analysis, multiple imputation, and inverse probability weighting. Of 20,899 eligible adults, 15,897 (76%) were interviewed, 13,490/15,897 (85%) had X-ray, and 1,120/1,394 (80%) sputum-eligible participants produced at least one specimen, giving 15,318 complete cases (5,895, 38% men). 29/15,318 had bacteriologically-confirmed TB (189 per 100,000 complete-case (cc) / 150 per 100,000 with inverse weighting (iw)). Men had higher burden (cc: 305 [95% CI:144–645] per 100,000) than women (cc: 117 [95% CI:65–211] per 100,000): cc adjusted odds ratio (aOR) 2.70 (1.26–5.78). Other significant risk factors for prevalent TB on complete-case analysis were working age (25–49 years) and previous TB treatment, but not HIV status. Multivariable analysis of imputed data was limited by small numbers, but previous TB and age group 25–49 years remained significantly associated with higher TB prevalence. Pulmonary TB prevalence for Blantyre was considerably lower than the 1,014 per 100,000 for urban Malawi in the 2013–14 national survey, at 150–189 per 100,000 adults, but some groups, notably men, remain disproportionately affected. TB case-finding is still needed for TB elimination in Blantyre, and similar urban centres, but should focus on reaching the highest risk groups, such as older men
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