27 research outputs found

    Assessment of the primary and intermediate school staffs’ knowledge, attitude and practice on care of children with Type 1 diabetes at school, Al-Jouf, Saudi Arabia

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    Background: Children with diabetes type 1 (T1DM) need close monitoring for their blood glucose, food intake, insulin therapy and physical activity during school hours in order to guard against the development of acute and long-term complications.Objectives: To evaluate the current situation of management of T1DM in primary and intermediate schools children through assessment of the working staffs’ attitude, knowledge and practice at Al-Jouf, Saudi Arabia.Materials and Methods: This descriptive cross-sectional study enrolled consented voluntarily participating working staffs from primary and intermediate schools in Al-Jouf region, Saudia Arabia. A questionnaire (included 23 questions) testing knowledge, attitudes and practice regarding T1DM and care of diabetic children was used.Results: 744 teachers were studied (62.1% females) where 58.1%of them were working in primary schools. Of all, 69% were class teachers, 20.4% administrators, 8.6% school counselors, and 2% physical education teachers. 75.4% of the participants had adequate general knowledge about diabetes. Only 43.78% of the respondents had specific knowledge about diabetes in the school and teachers with a family diabetic patient showed higher knowledge about diabetes vs. their counterparts. Only 16.0% of the participants reported that their schools have trained personnel in diabetes. Large proportion of study teachers’ (94%) was willing to join a training program for care of diabetic students. Of the total group of teachers, 665 support recruitment of a school nurse.Conclusion: Diabetes care training programs for school teachers and staffs, availability of school nurses and instigating collaboration between the diabetic center and the school is essential for safety of such diabetes student patients in the schools.Keywords: Type 1 Diabetes mellitus, School teachers, Training programs, Diabetes care, Knowledge about diabetes, School nurse, Diabetes care at the schoo

    Electrodeposition of Ni-Si Schottky barriers

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    Electrodeposition is being used to fabricate magnetic microstructures directly on patterned n-type Si wafers of various substrate resistivities. The Ni-Si Schottky barrier is characterized and found to be of high quality for relatively low Si resistivities (1-2 Omega(.)cm), with extremely low reverse leakage. It is shown that a direct correlation exists among the electrodeposition potential, the roughness, and the coercivity of the films. A conductive seed layer or a back contact is not compulsory for electrodeposition on Si with resistivities up to 15 Omega(.)cm. This shows that electrodeposition of magnetic materials on Si might be a viable fabrication technique for magnetoresistance and spintronics applications

    Shape-induced anisotropy in antidot arrays from self-assembled templates

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    Using self-assembly of polystyrene spheres, well-ordered templates have been prepared on glass and silicon substrates. Strong guiding of self-assembly is obtained on photolithographically structured silicon substrates. Magnetic antidot arrays with three-dimensional architecture have been prepared by electrodeposition in the pores of these templates. The shape anisotropy demonstrates a crucial impact on magnetization reversal processes

    Electrodeposition of Ni-Si Schottky barriers

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    Electrodeposition of Ni-Si Schottky barriers

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    Electrodeposition is being used to fabricate magnetic microstructures directly on patterned n-type Si wafers of various substrate resistivities. The Ni-Si Schottky barrier is characterized and found to be of high quality for relatively low Si resistivities (1-2 Omega(.)cm), with extremely low reverse leakage. It is shown that a direct correlation exists among the electrodeposition potential, the roughness, and the coercivity of the films. A conductive seed layer or a back contact is not compulsory for electrodeposition on Si with resistivities up to 15 Omega(.)cm. This shows that electrodeposition of magnetic materials on Si might be a viable fabrication technique for magnetoresistance and spintronics applications

    Genome-wide association study for systemic lupus erythematosus in an egyptian population

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    Systemic lupus erythematosus (SLE) susceptibility has a strong genetic component. Genome-wide association studies (GWAS) across trans-ancestral populations show both common and distinct genetic variants of susceptibility across European and Asian ancestries, while many other ethnic populations remain underexplored. We conducted the first SLE GWAS on Egyptians–an admixed North African/Middle Eastern population–using 537 patients and 883 controls. To identify novel susceptibility loci and replicate previously known loci, we performed imputation-based association analysis with 6,382,276 SNPs while accounting for individual admixture. We validated the association analysis using adaptive permutation tests (n = 109). We identified a novel genome-wide significant locus near IRS1/miR-5702 (Pcorrected = 1.98 × 10−8) and eight novel suggestive loci (Pcorrected 0.8) with lead SNPs from four suggestive loci (ARMC9, DIAPH3, IFLDT1, and ENTPD3) were associated with differential gene expression (3.5 × 10−95 < p < 1.0 × 10−2) across diverse tissues. These loci are involved in cellular proliferation and invasion—pathways prominent in lupus and nephritis. Our study highlights the utility of GWAS in an admixed Egyptian population for delineating new genetic associations and for understanding SLE pathogenesis

    A Full-Bridge Submodule-Based Modular Unipolar/Bipolar High-Voltage Pulse Generator with Sequential Charging of Capacitors

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    Repetitive high pulsed electric field (PEF) is an effective method to kill microorganisms and bacteria in water treatment applications. The PEF can be generated by applying high-power electromagnetic pulse across the sample to be treated. There are two main types of high-voltage pulse generators, namely, unipolar and bipolar. In this paper, a full-bridge submodule-based modular high-voltage pulse generator, having the ability to generate unipolar and bipolar high-voltage pulses with different shapes from a relatively low-voltage input dc supply, is proposed. In the proposed configuration, relatively low-voltage insulated gate bipolar transistors (IGBTs) are required to generate the high-voltage bipolar pulses. A thyristor rated at the level of the pulsed output voltage is required in the proposed configuration to bypass the load during the charging process of capacitors. In the proposed approach, a thyristor is used instead of the self-commutated high-voltage switch (e.g., series-connected IGBTs), as thyristors are available with high-voltage ratings and possess inherent reverse voltage blocking capability. A detailed illustration of the proposed configuration and its operational concept are introduced in this paper. Simulation and experimental results are presented to validate the proposed approach.Qatar National Research FundScopu

    Self-balanced non-isolated hybrid modular DC-DC converter for medium-voltage DC grids

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    Here, a new bi-directional hybrid modular non-isolated DC-DC converter is proposed where it consists of a boost converter (BC) fed from the high-voltage (HV) side. At the BC output stage, a certain number of half bridge submodules (HBSMs) is connected across the BC switch. During the turn-on period of BC switch, the HB-SMs are connected sequentially to the low-voltage (LV) side, which results in charging/discharging their capacitors from/into the LV side. While, during the turn-off period, the LV side is bypassed and the HB-SMs capacitors are connected in series across the BC output stage, which results in discharging/charging them into/from the HV side. The power flow is controlled in both directions by controlling the duty cycle. The proposed configuration provides self-balancing operation thanks to the sequential connection of HB-SMs capacitors, and it also provides the ability to operate with high conversion ratios. Illustration and analysis of the proposed converter and its closedloop controller are presented. A full design of the values and ratings of the involved components are presented. Simulation study for a 2.5 MW (25 kV/10 kV) DC-DC converter is presented. Finally, experimental results for a downscaled prototype are presented for validation

    Modular Multilevel Converter with Self-Energy Equalization for Medium Voltage AC Drive Applications

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    The modular multilevel converter (MMC) is a promising candidate for high-/medium-voltage high-power applications such as medium voltage ac drives due to its modularity, reliability, and scalability. The main challenge of a conventional MMC is low-frequency operation. Capacitor voltage ripple is inversely proportional to the operating frequency. Hence, operating at low frequency necessitates employing large submodule capacitances to limit voltage ripple or the utilization of energy equalization modules (EEMs). The first option negatively affects converter lifetime, and the second option requires a large number of semiconductor devices and isolating transformers. In this article, a modified MMC topology with self-energy equalization is proposed to ensure converter operation with balanced capacitor voltages with low ripple during zero-/low-frequency conditions. Operating with balanced capacitor voltages with low ripple is achieved by maintaining the same energy level in the involved upper and lower arms. A low device count alternative to the EEMs approach is proposed in this work. Detailed illustration of the operational concept and design of the associated passive components is presented. The performance of the proposed medium voltage ac drive is elucidated through simulation and experimental results.Scopu
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