170 research outputs found

    Variation of Electrostatic Coupling and Investigation of Current Percolation Paths in Nanocrystalline Silicon Cross Transistors

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    Nanocrystalline silicon thin films are promising materials for the development of advanced Large Scale Integration compatible quantum-dot and single-electron charging devices. The films consist of nanometer-scale grains of crystalline silicon, separated by amorphous silicon or silicon dioxide grain boundaries up to a few nanometer thick. These films have been used to fabricate single-electron transistor and memory devices, where the grains form single-electron charging islands isolated by tunnel barriers formed by the grain boundaries. The grain boundary tunnel barrier isolating the grains is also of great importance, as this determines the extent of the electrostatic and tunnel coupling between different grains. These effects can lead to the nanocrystalline silicon thin film behaving as a system of coupled quantum dots.& more..

    Assessment of genotype x environment interaction and stability of sesame (Sesamum indicum L.) seed yield under rainfed and supplementary irrigation in central Sudan

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    ABSTRACT       Sesame knowledge of genotype x environment interaction (GEI) is advantageous in order to have a cultivar that gives consistently high yield in a broad range of environments and to increase the efficiency of breeding programs and selection of the best genotypes. Fifteen genotypes of sesame (Sesamum  indicum L.) were evaluated during 2011 and 2012 rainy seasons, at Wad Medani, Rahad (under supplementary irrigation) and Gedarif (under rainfed), to assess genotype x environment interaction and stability of seed yield. A randomized complete block design with four replicates was used in each location. The analysis of variance procedure revealed highly significant differences among the 15 sesame genotypes for seed yield over the eight environments. The mean squares of environment, genotype and genotype x environment interaction were highly significant for seed yield. Both statistical stability models, i. e. Eberhart and Russell (1966) as well as the Additive Main Effect and Multiplicative Interaction (AMMI) analysis, indicated that genotypes Elgezouli, Promo, Um Shagra and Kenana-2 were the most high yielding and stable genotypes and can be recommended for both rainfed and irrigated areas of central Sudan.                من ميزات دراسة التفاعل الوراثي- البيئي في محصول السمسم معرفة افضل الاصناف ذات الانتاجية العالية في مدي واسع من البيئات المختلفة مما يزيد من كفاءة برامج التربية المستعملة وانتخاب افضل الاصناف. تم تقويم 15 سلالة من السمسم في الموسمين الزراعيين 2011 و2012م في ثلاثة مواقع هي مدني، الرهد (ري تكميلي) والقضارف (ري مطري)، وذلك لتقويم التفاعل الوراثي والبيئي وثبات درجة انتاجية بذور السمسم. استخدم تصميم القطاعات العشوائية الكاملة بأربع مكررات. اظهرت نتائج تحليل التباين لعدد 15 سلالة من السمسم فروقات معنوية عالية جدا لمعظم الصفات التي درست في كل المواقع والمواسم مع معنوية للتفاعل الوراثي والبيئي لإنتاجية البذور. بناءاً علي نماذج التحليل Eberhart and Russel (1966)              وAdditive Main Effect and Multiplicative Interaction(AMMI) لتحديد ثبات الاداء معاً وجد ان انتاجية بذور الاصناف الجزولي، برومو، ام شجرة وكنانة-2 ثابتة وعالية في كل المواقع والمواسم. وبناءاً علي ذلك يوصي بزراعة هذه الاصناف في المناطق المطرية والمروية في وسط السودان.                   &nbsp

    Single donor ionization energies in a nanoscale CMOS channel

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    One consequence of the continued downwards scaling of transistors is the reliance on only a few discrete atoms to dope the channel, and random fluctuations of the number of these dopants is already a major issue in the microelectonics industry. While single-dopant signatures have been observed at low temperature, studying the impact of only one dopant up to room temperature requires extremely small lengths. Here, we show that a single arsenic dopant dramatically affects the off-state behavior of an advanced microelectronics field effect transistor (FET) at room temperature. Furthermore, the ionization energy of this dopant should be profoundly modified by the close proximity of materials with a different dielectric constant than the host semiconductor. We measure a strong enhancement, from 54meV to 108meV, of the ionization energy of an arsenic atom located near the buried oxide. This enhancement is responsible for the large current below threshold at room temperature and therefore explains the large variability in these ultra-scaled transistors. The results also suggest a path to incorporating quantum functionalities into silicon CMOS devices through manipulation of single donor orbitals

    Impact of body composition analysis on male sexual function: A metabolic age study

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    Introduction: Metabolic Age (MetAge) and body composition analysis may reflect an individual’s metabolic status, which is believed to influence male sexual and gonadal functions. Although erectile dysfunction (ED) and hypogonadism are increasingly prevalent with age, they are also detected among younger men. This study aims to assess the impact of MetAge and body composition on male sexual and gonadal status overall, and particularly in men younger than 40 years of age. Methods: This was a cross-sectional study of 90 male healthcare workers, between the ages of 18-55, randomly selected based on their corporation numbers. In addition to Bioelectric Impedance Analysis, subjects were requested to fill the International Index of Erectile Function questionnaire (IIEF-5) and to provide an early morning serum testosterone (T) sample. Results: The mean participants’ age was 39.4 ± 9.4 years, MetAge was 45.54 ± 10.35 years, serum T level was 13.68 ± 4.49 nmol/L and BMI was 28.8 ± 4.7 kg/m2. Significant negative correlations were obtained between serum T, MetAge, body weight and fat composition. Significant negative correlations between the IIEF-5 score, MetAge, and fat composition, were only reported in subjects <40 years of age. Significantly lower T levels (p=0.002), significantly older MetAge (p=0.034), and higher BMI (p=0.044) and degree of obesity (p=0.042) were observed in participants <40 years with erectile dysfunction (ED) compared to their counterparts without ED. Discussion: MetAge and body composition parameters significantly impact the androgenic state. ED in men <40 years is associated with lower T levels, older MetAge and higher BMI and degree of obesity

    Endocrine contribution to the sexual dysfunction in patients with advanced chronic kidney disease and the role of hyperprolactinemia.

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    In this study, we investigated the prevalence of sexual dysfunction among males with advanced chronic kidney disease and the effect of treating hyperprolactinemia among these patients. In this prospective study, patients were assessed with history, physical examination, hormonal assessment, and two questionnaires, IIEF and AIPE. Patients with hyperprolactinemia received treatment with cabergoline 0.5 mg once per week for 6 months and were re-evaluated. A total of 102 patients were included in this study, 75 (73.53%) were on hemodialysis, 13 (12.75%) on peritoneal dialysis and 14 (13.73%) on medical treatment alone. Ninety (88.24%) patients had premature ejaculation, 85 (83.33%) had anything from mild-to-moderate-to-severe erectile dysfunction. The incidence of hypogonadism and hyperprolactinemia was 34.4%. Patients treated with cabergoline (n = 26) showed a significant increase in LH levels (p = .003) and a significant decrease in prolactin levels (p = .003). Testosterone levels and the incidence of erectile dysfunction or premature ejaculation did not improve significantly. There is a high incidence of sexual dysfunction among patients. Treatment of hyperprolactinemia is effective in correcting prolactin levels, but does not improve erectile dysfunction or premature ejaculation. Therefore, treating hyperprolactinemia is not an overall effective treatment for erectile dysfunction in these patients

    The effect of sperm DNA fragmentation on intracytoplasmic sperm injection outcome

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    Our study objective was to assess the effect of various sperm DNA fragmentation levels on clinical intracytoplasmic sperm injection outcome. This retrospective study included 392 patients who underwent ICSI and performed sperm DNA fragmentation testing before the procedure. Based on sperm DNA fragmentation cut-off values, the patients were differentiated into 3 groups as 30%. According to the female status, patients were differentiated into favourable group (n = 259) with female age <35 years and anti-Mullerian hormone level ≥7.1 pmol/L; and unfavourable group (n = 133) with female age ≥35 years and anti-Mullerian hormone level ≤7.1 pmol/L. The patient's medical records were reviewed, and patient's demographic, laboratory data including semen analysis, sperm DNA fragmentation determined by means of sperm chromatin dispersion, hormonal profile and data regarding intracytoplasmic sperm injection cycle were collected. This cohort reported that the clinical reproductive outcomes of intracytoplasmic sperm injection showed no statistical significance with increase sperm DNA fragmentation levels. In sperm DNA fragmentation above 30%, favourable females had significantly higher clinical pregnancy rate and live birth rate than unfavourable females, while fertilisation rate and miscarriage rate showed no significance between the subgroups. High sperm DNA fragmentation is linked to poor semen parameters
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