Simulation Study on the Open-Circuit Voltage of Amorphous Silicon p-i-n Solar Cells Using AMPS-1D

AMPS-1D (Analysis of Microelectronic and Photonic Structure) simulation program was used to simulate Amorphous Silicon p-i-n Solar Cell. The simulated result of illuminated current density-voltage characteristics was in a good agreement with experimental values. The dependence of the open-circuit voltage on the characteristics of the a-Si:H intrinsic layer was investigated. The simulation result shows that the open-circuit voltage does not depend on the thickness of the intrinsic layer. The open-circuit voltage decreases when the front contact barrier height is small or the energy gap of the intrinsic layer is small. The open-circuit voltage increases when the distribution of the tail states is sharp or the capture cross sections of these states are small. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3432

Functional and genetic studies in Type 2 diabetes and obesity

Type 2 diabetes (T2D) and obesity are highly prevalent disorders reflecting a complex interplay of genetics, epigenetics, and environment. They constitute serious health problems and lead to significant morbidity and mortality. The overall aim of this thesis was to shed some light on the molecular mechanisms underlying pathogenesis of T2D and obesity by studies in rat and man. In Paper I, adenylyl cyclase 3 (Ac3) mRNA expression levels in pancreatic islets and striatum/hypothalamus regions of brain of diabetic Goto-Kakizaki (GK) rats were higher compared with control Wistar rats, while its expression was intermediate in islets and brain regions of insulin-treated GK rats. This study proposes that increased Ac3 mRNA expression in these tissues is partially a primary and inherited defect and not solely secondary to hyperglycaemia, and that AC3 may participate in the regulation of glucose homeostasis via insulin secretion and CNS. In Paper II, protein kinase Cα (PKCα) and PKCζ mRNA expressions in pancreatic islets were decreased in GK compared with Wistar rats, with intermediate expressions in the insulin-treated GK group. PKCα and phosphorylated PKCα (p-PKCα) protein expressions in islets were diminished in GK compared with insulin-treated GK and Wistar rats. Islet PKCζ protein expression was reduced in both GK and insulin-treated GK compared with Wistar rats, but p-PKCζ was reduced only in GK compared with insulin-treated GK and Wistar rats. PKCε was lower in islets of GK compared with insulin-treated GK and Wistar rats, at both the mRNA and protein levels. PKCδ and p-PKCδ protein expressions in islets were decreased in GK compared with insulin-treated GK and Wistar rats. In liver, PKCδ and PKCζ mRNA expressions were decreased in both GK and insulin-treated GK compared with Wistar rats. Hepatic PKCζ protein expression was diminished in GK rats with and without insulin treatment compared with Wistar rats. Although PKCδ showed no difference at the protein level, p-PKCδ/PKCδ was reduced in liver of GK compared with Wistar rats. PKCε mRNA expression in liver was down-regulated in insulin-treated GK compared with non-treated GK and Wistar rats. Therefore, this study suggests defects in PKCα and PKCε expressions in pancreatic islets of GK rats secondary to hyperglycaemia. In liver, PKCε mRNA expression in liver could be under control of insulin. In Paper III, mRNA expressions, enzyme activities, and protein levels of succinyl-CoA:3-ketoacid-CoA transferase (SCOT) and ATP citrate lyase (ATPCL) were decreased in pancreatic islets of GK compared with Wistar rats. Two cell lines with the severest knockdown of SCOT enzyme activity and protein, SCOT 1676 and SCOT 1184, showed the severest reduction in secretagogue-stimulated insulin secretion. This study confirms that the mitochondrial pathways involving SCOT, instead of or synergizing with the pathway involving ATPCL, are important potentiators of glucose-stimulated insulin secretion (GSIS). In Paper IV, we studied the association of adrenergic receptor alpha 2A (ADRA2A) genetic polymorphisms with obesity and/or T2D in a Swedish cohort. The single nucleotide polymorphism (SNP) rs553668 was associated with T2D in men, but this association disappeared after adjusting for age and body mass index (BMI). Associations were also detected when comparing obese subjects with normal glucose tolerance (NGT) and lean NGT subjects, and in obese but not lean T2D patients. In women, multiple logistic regression regarding SNP rs521674 demonstrated an association with T2D when including age as a covariant. However, correcting for BMI removed this association. When age was included in the model, the increased risk of rs521674 was seen in obese, but not in lean, T2D women. This study provides evidence that ADRA2A genetic polymorphisms are mainly associated with obesity and may also relate to T2D in a Swedish population. In conclusion, this thesis has revealed molecular pathogenetic defects related to T2D and obesity, and may thus create a basis for more precise and improved therapeutic approache

Comparison of the Microwave-Heated Ziehl-Neelsen Stain and Conventional Ziehl-Neelsen Method in the Detection of Acid-Fast Bacilli in Lymph Node Biopsies

BACKGROUND: Tuberculosis is a chronic inflammatory disease with lymphadenopathy being the most common extra-pulmonary manifestation. The conventional Ziehl–Neelsen method plays an essential role in the diagnosis of tuberculosis; however, it has a low sensitivity in detecting acid-fast bacilli. AIM: The present study emphasises the role of the microwave-heated method (modified Ziehl–Neelsen) over conventional Ziehl-Neelsen stain and to set at the best condition for irradiation. MATERIAL AND METHODS: The study included 90 patients with clinically suspected tuberculous lymphadenopathy who were referred to the Department of Pathology at Omdurman Military Hospital, Sudan. Demographic data such as age, sex, and site of swelling were documented for each patient. Specimens were stained with conventional Ziehl-Neelsen, fluoresce and the modified methods. RESULTS: Patient’s age ranged from 20 to 70 year. Of the total 90 cases with clinically suspected tuberculous lymphadenopathy, 18 cases were positive for AFB in conventional Ziehl-Neelsen method giving a sensitivity of 13.3%, while in microwave-heated method 82 cases of TB were detected positive for AFB yielded sensitivity and specificity of 97.6% and 85.7%, respectively, and positive and negative predictive values of 98.8% and 75.0% respectively compared to fluorescence methods. CONCLUSION: In the present study, the microwave-heated Ziehl-Neelsen method, was found to have sensitivity and specificity of 97.6% and 85.7%, respectively which matches the fluorescence technique. It has specificity in detecting lymph node tuberculosis that makes it superior over all other modified methods. However, the availability and cost-effectiveness might limit the use of fluorescence in routine practice. Furthermore, the study set the best staining temperature is provided at power 1 level (60 w) for 1.5 minutes

Perceptions and Attitudes of Jordanian Medical Students on Using 3D Interactive Anatomy Dissection in Teaching and Learning Anatomy

Background and Aims: This study evaluates the use of virtual anatomy dissection (Anatomage Table) in teaching anatomy for Jordanian medical students. The study also highlights any gender differences in students’ perception on this method of teaching anatomy. Methods: This is a cross-sectional questionnaire-based study that was carried out on medical students enrolled in Al-Balqa Applied University, a Jordanian public university. A group of expert anatomists designed a questionnaire that investigates the students’ perceptions and attitudes toward using virtual anatomy dissection. The questionnaire also investigated student’s opinions and expectations on the impact of using this method on the academic achievement of students. Results: The findings of the study showed that most students agreed that Anatomage Table helped them better understand (64.3%) and memorize (64%) anatomy lectures. In addition, most students were interested in using this learning method in lab groups (72.3%). However, the didactic approach that combined anatomical models and the Anatomage Table was preferred over the unilateral approach that included only the Anatomage Table (80.5% vs 30.2%, p<0.001, r=0.9). Of note, there was a statistically significant difference between males and females in their preference for Anatomage Table (p<0.001), and in their perceptions on the impact of Anatomage Table on understanding of lectures (p<0.001) and memorization of anatomical structures (p=0.004). Conclusion: The Anatomage Table is a powerful teaching and learning method in undergraduate medical education. Its application to Al-Balqa Applied University has proven to be effective so far. It can be used to overcome the problems facing anatomical education in the college of medicine in Al-Balqa Applied University and perhaps other universities in Jordan, but this needs better cooperation between universities and stakeholders to provide adequate funding for this method.Qatar University funded Open Access publication

Teaching Musculoskeletal Module using dissection videos: feedback from medical students.

Over the last two decades many medical schools have been exploring alternatives to hands-on cadaver dissection in teaching anatomy. This study aimed at reporting medical students' feedback on using dissection videos in teaching anatomy of the musculoskeletal system. Dissection videos were used to teach the anatomy of the musculoskeletal system for third year medical students. At the end of the module, feedbacks from medical students were reported using a questionnaire designed for this purpose. Statistically valid responses were considered for 284 students. Around 60% of the students enjoyed learning anatomy by watching dissection videos but the majority - mostly non-Jordanian - thought that the duration of the videos should be shorter. 83% (236/284)of the students enjoyed the presence of an instructor to guide them through the video and 85% (241/284) wanted to discuss the content with the instructor after watching. Most of the students liked to have access to the videos at any time in an open lab policy. Only 23% (66/284) of the students - mostly Jordanian - were willing to completely replace cadaveric prosections with dissection videos. Most of the students found that dissection videos helped them to understand anatomy lectures in a better way and in memorizing anatomical details. A significantly higher percentage of Jordanian students preferred watching dissection videos at home and preferred dissection videos to replace traditional anatomy lab sessions. In the light of our present findings, using dissection videos as a teaching method of anatomy was well received by students. However, it seemed that the students wanted dissection videos to be integrated with using cadaveric prosections rather than replacing them.The study was funded by Deanship of research, Jordan University of science and Technology (JUST). Dr Ayman G. Mustafa is currently at leave from JUST

Reservoir monitoring using streaming potential; is the thermoelectric correction necessary?

Wellbore streaming current and their applicability in the location of subsurface sand bodies were discovered in 1931 and the usefulness of this measurement has persisted to the present day. Through the endeavor of many researchers, knowledge and understanding of streaming potential (SP) have slowly evolved from the original mere recognition of its existence to its present-day quantitative use in many applications such as Enhanced Oil Recovery (EOR), water flooding, intelligent wells, etc. The spontaneous potential acts to maintain overall electroneutrality when a separation of electrical charge occurs in response to gradients in pressure (Electrokinetic), chemical composition (Electrochemical), or temperature (Thermoelectric). In spite of it being discovered 70 years ago, unfortunately little work has been done to find measurable value especially for thermoelectric coupling coefficient. Many researchers attempt to generate a universal model for SP. They attributes the limitations (if any) of their model to the scarce availability of accurate estimation for coupling coefficient. This study measures the value of thermoelectric coupling coefficient for five rock samples saturated with 0.01M (NaCl) saline brine. The study takes account of temperature dependant electrode effect. The result shows value of 0.2 mV/K, which is in a good match with most of the published data. It was also found that there is no strong correlation between the thermoelectric coupling coefficient and porosity. The measured thermoelectric values are considered insignificantly small compared to the electrokinetic effect in the system

Expression of Protein Kinase C Isoforms in Pancreatic Islets and Liver of Male Goto-Kakizaki Rats, a Model of Type 2 Diabetes

<div><p>Protein kinase C (PKC) is a family of protein kinases controlling protein phosphorylation and playing important roles in the regulation of metabolism. We have investigated expression levels of PKC isoforms in pancreatic islets and liver of diabetic Goto-Kakizaki (GK) rats with and without insulin treatment to evaluate their association with glucose homeostasis. mRNA and protein expression levels of PKC isoforms were assessed in pancreatic islets and liver of Wistar rats and GK rats with or without insulin treatment. PKCα and PKCζ mRNA expressions were down-regulated in islets of GK compared with Wistar rats. PKCα and phosphorylated PKCα (p-PKCα) protein expressions were decreased in islets of GK compared with insulin-treated GK and Wistar rats. PKCζ protein expression in islets was reduced in GK and insulin-treated GK compared with Wistar rats, but p-PKCζ was decreased only in GK rats. Islet PKCε mRNA and protein expressions were lower in GK compared with insulin-treated GK and Wistar rats. In liver, PKCδ and PKCζ mRNA expressions were decreased in both GK and insulin-treated GK compared with Wistar rats. Hepatic PKCζ protein expression was diminished in both GK rats with and without insulin treatment compared with Wistar rats. Hepatic PKCε mRNA expression was down-regulated in insulin-treated GK compared with GK and Wistar rats. PKCα, PKCε, and p-PKCζ expressions were secondary to hyperglycaemia in GK rat islets. Hepatic PKCδ and PKCζ mRNA expressions were primarily linked to hyperglycaemia. Additionally, hepatic PKCε mRNA expression could be under control of insulin.</p></div

Characteristics of diabetic GK and control Wistar rats.

<p>Before and after the 14-day treatment period, the body weights (A) and plasma glucose levels (B) were assessed in Wistar, insulin-treated GK, and non-treated GK rats. After the 14-day treatment period, the serum insulin levels (C) were assessed in the three groups of rats. Data are means ± SE (n = 10). *p < 0.05, **p < 0.01, ***p < 0.001 vs. Wistar rats; ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 vs. GK rats. ^§§p < 0.01, ^§§§p < 0.001.</p