Hydrodynamic Analysis and Responsivity improvement of a metal/semiconductor/metal plasmonic detector

Characteristics improvement of photon/plasmon detectors have been the subject of several investigations in the area of plasmonic integrated circuits. Among different suggestions, Silicon-based Metal-Semiconductor-Metal (MSM) waveguides are one of the most popular structures for implementation of high-quality photon/plasmon detectors in infrared wavelengths. In this paper, an integrated Silicon Germanium (SiGe) core MSM plasmon detector is proposed to detect lambda=1550 nm with internal photoemission mechanism. Performance characteristics of the new device are simulated with a simplified hydrodynamic model. In a specific bias point (V=3 V and the incident optical power of 0.31 mW), the output current is 404.3 uA (276 uA detection current and 128.3 uA dark current), responsivity is 0.89 A/W and the 3-dB electrical bandwidth is 120 GHz. Simulation results for the proposed Plasmon detector, in comparison with the empirical results of a reported Si-based MSM device, demonstrate considerable responsivity enhancement.Comment: 12 pages; 12 figure

Application of Chitosan and Activated Carbon Nano-composite in Removal of Nitrite, Phosphate, and Ammonia From Aquaculture Wastewater

Developing an adsorbent with natural components is one of the effective methods to reduce the amount of wastewater pollutants. Wastewater reuse can improve the quality of water prior to entering the natural environment. The aim of this study was to evaluate the efficiency of chitosan nano-composite and activated carbon adsorbent in the removal of nitrite, phosphate, and ammonia pollutants from fish farms of Aq-Qala. To prepare the adsorbents, the shrimp shells were converted to nano-chitosan. The date palm kernel was prepared and activated with oxalic acid in pyrolysis furnace by injecting nitrogen gas into activated carbon, then, the nano-composite was prepared from nanochitosan and activated carbon. A field-laboratory study was conducted during the winter of 2018, and then, batches of synthesized nano-composite were investigated and the effects of pH, initial effluent concentration, and adsorption time were investigated. The experiments were performed in the pH range of 5-8, effluent concentration of 25-100 mg/L, and contact time of 15-90 minutes. The results showed that at optimum conditions (pH of 7, effluent concentration of 50 mg/L, and contact time of 60 minutes), the highest removal percentage and adsorption capacity for nitrite, phosphate, and ammonia contaminants were 99.98%, 99.77%, and 65.65%, and 6.65, 6.14, and 7.32 mg/g , respectively. Due to the high removal percentage (99.98%) of the chitosan and activated carbon nano-composite, the adsorbent was highly capable of removing pollutants (nitrite, phosphate, and ammonia)

Causal Model of the Association between Academic Burnout and Achievement Goals: The Intermediating Role of Self-Efficacy and Procrastination

Background & Objective: There has been growing recognition that medical students, interns, residents, and practicing physicians across many specialties are prone to burnout, with recent studies linking high rates of burnout to adverse mental health issues. The aim of this study was to examine factors affecting academic burnout among medical students and investigate the association between achievement goals and its dimensions, academic self-efficacy, and academic procrastination in the form of a causal model. Methods: For this purpose, 174 students (98 in the clinical stage and 76 in the preclinical stage) of Shiraz University of Medical Sciences (Iran) were selected based on Cochran’s Formula and through simple random sampling. The data collection tools consisted of the Maslach Burnout Inventory-Student Survey (MBI-SS), Achievement Goal Questionnaire (Elliot and McGregor), Academic Self-Efficacy Scale (Midgley et al.), and Academic Procrastination Scale (Savari). To analyze the data, path analysis and the Pearson correlation coefficient were used. Results: The resulting path models indicated that academic burnout had significant negative relationships with mastery achievement goal, performance-approach, and academic self-efficacy, but it had significantly positive relationships with academic procrastination and performanceavoidance. It was also found that achievement goals had impact on academic burnout through academic procrastination and self-efficacy. The explained variance of academic burnout was 0.61. Conclusion: It was found that achievement goals and academic self-efficacy had significant effects on academic procrastination and burnout. Thus, it is suggested that those involved in education provide the students with situations in which they can achieve a higher sense of empowerment in learning, so that they become more engaged in their academic work and be less likely to experience burnout. Key Words: Academic burnout, Achievement goals, Academic self-efficacy, Academic procrastinatio

Phenotypic and geographic variation among populations of the Platyceps rhodorachis-ventromaculatus species complex (Ophidia: Colubridae) in Iran

Geographical diversity appears in the phenotype of different populations of a given species and specific geographical factors are directly or indirectly involved in this variation. Due to their wide distribution range, snakes of the genus Platyceps Blyth, 1860 are wonderful case studies for morphological evaluation. In this study, 49 specimens of the Platyceps rhodorachis-ventromaculatus species complex in four different geographic areas from Iran were examined using morphological characters. The results of statistical analysis did not show any sexual dimorphism except in the character of Gular scales (P value = 0.038), but did show significant variation in the number of scales and in other morphological characters among populations in this group. Generally, four morphological clusters were distinguished with Sistan and Baluchistan population being the most distinct from the others. Additionally, there was a visible slope of changes in some morphological characters associated with latitude, so that body size of the specimens increases with increasing latitude

Attenuation of oxidative and nitrosative stress in cortical area associates with antidepressant-like effects of tropisetron in male mice following social isolation stress.

Tropisetron, a 5-HT3 receptor antagonist widely used as an antiemetic, has been reported to have positive effects on mood disorders. Adolescence is a critical period during the development of brain, where exposure to chronic stress during this time is highly associated with the development of depression. In this study, we showed that 4 weeks of juvenile social isolation stress (SIS) provoked depressive-like behaviors in male mice, which was associated with disruption of mitochondrial function and nitric oxide overproduction in the cortical areas. In this study, tropisetron (5 mg/kg) reversed the negative behavioral effects of SIS in male mice. We found that the effects of tropisetron were mediated through mitigating the negative activity of inducible nitric oxide synthase (iNOS) on mitochondrial activity. Administration of aminoguanidine (specific iNOS inhibitor, 20 mg/kg) augmented the protective effects of tropisetron (1 mg/kg) on SIS. Furthermore, l-arginine (nitric oxide precursor, 100 mg/kg) abolished the positive effects of tropisetron. These results have increased our knowledge on the pivotal role of mitochondrial function in the pathophysiology of depression, and highlighted the role of 5-HT3 receptors in psychosocial stress response during adolescence. Finally, we observed that tropisetron alleviated the mitochondrial dysfunction through decreased nitrergic system activity in the cerebral corte

Significance of left ventricular apical-basal muscle bundle identified by cardiovascular magnetic resonance imaging in patients with hypertrophic cardiomyopathy

Aims Cardiovascular magnetic resonance (CMR) has improved diagnostic and management strategies in hypertrophic cardiomyopathy (HCM) by expanding our appreciation for the diverse phenotypic expression. We sought to characterize the prevalence and clinical significance of a recently identified accessory left ventricular (LV) muscle bundle extending from the apex to the basal septum or anterior wall (i.e. apical-basal). Methods and results CMR was performed in 230 genotyped HCM patients (48 ± 15 years, 69% male), 30 genotype-positive/phenotype-negative (G+/P−) family members (32 ± 15 years, 30% male), and 126 controls. Left ventricular apical-basal muscle bundle was identified in 145 of 230 (63%) HCM patients, 18 of 30 (60%) G+/P− family members, and 12 of 126 (10%) controls (G+/P− vs. controls; P < 0.01). In HCM patients, the prevalence of an apical-basal muscle bundle was similar among those with disease-causing sarcomere mutations compared with patients without mutation (64 vs. 62%; P = 0.88). The presence of an LV apical-basal muscle bundle was not associated with LV outflow tract obstruction (P = 0.61). In follow-up, 33 patients underwent surgical myectomy of whom 22 (67%) were identified to have an accessory LV apical-basal muscle bundle, which was resected in all patients. Conclusion Apical-basal muscle bundles are a unique myocardial structure commonly present in HCM patients as well as in G+/P− family members and may represent an additional morphologic marker for HCM diagnosis in genotype-positive statu