Overarching Preventive Sympathetic Tripping Approach in Active Distribution Networks Without Telecommunication Platforms and Additional Protective Devices

Nowadays, distributed generation (DG) has made it possible to generate electricity close to the consumption site, resulting in improved efficiency, less environmental pollution, and higher economic profit. These advantages have led to increased penetration of DGs in the distribution system. Protective devices in a distribution system are set by considering the main substation as the only source for feeding short circuit current. However, with the increased influence of DGs as the second main source of short circuit current in distribution systems the short circuit level changes, which leads to false tripping of protective devices, including overcurrent relays. A sympathetic trip, occurring due to a fault in the adjacent feeder, is one of the most serious challenges. This paper analyzes the sympathetic trip in the presence of synchronous based DGs. The equations related to the participation of DGs and upstream network in feeding the short circuit current are obtained. The effect of different parameters on the probability of occurrence of a sympathetic trip is also investigated. Moreover, a novel fast solution is presented for overcoming the sympathetic trip of synchronous based DGs. The proposed method is introduced using the positive-sequence currents of the DGs and main substation. The sympathetic trip is predicted by adopting this prediction index and its occurrence is avoided. The proposed methodology is independent of telecommunication platforms and additional protective devices and can be applied to various short circuits. The method is tested on a network by simulating in DIgSILENT PowerFactory software. Simulation results show the effectiveness of the proposed methodology in predicting and preventing sympathetic trips

An Experimental Investigation of Ultraweak Photon Emission from Adult Murine Neural Stem Cells

Neurons like other living cells may have ultraweak photon emission (UPE) during neuronal activity. This study is aimed to evaluate UPE from neural stem cells (NSC) during their serial passaging and differentiation. We also investigate whether the addition of silver nanoparticles (AgNPs) or enhancement of UPE (by AgNPs or mirror) affect the differentiation of NSC. In our method, neural stem and progenitor cells of subventricular zone (SVZ) are isolated and expanded using the neurosphere assay. The obtained dissociated cells allocated and cultivated into three groups: groups: I: cell (control), II: cell + mirror, and III: cell + AgNPs. After seven days, the primary neurospheres were counted and their mean number was obtained. Serial passages continuous up to sixth passages in the control group. Differentiation capacity of the resulting neurospheres were evaluated in vitro by immunocytochemistry techniques. Measurement of UPE was carried out by photomultiplier tube (PMT) in the following steps: at the end of primary culture, six serial cell passages of the control group, before and after of the differentiation for 5 minutes. The results show that neither mirror nor AgNPs affect on the neurosphere number. The UPE of the NSC in the sixth subculturing passage was significantly higher than in the primary passage (P < 0.05). AgNPs significantly increased the UPE of the NSC compared to the control group before and after the differentiation (P < 0.05). Also, the treatment with AgNPs increased 44% neuronal differentiation of the harvested NSCs. UPE of NSC after the differentiation was significantly lower than that before the differentiation in each groups, which is in appropriate to the cell numbers (P < 0.0001). The mirror did not significantly increase UPE, neither before nor after the differentiation of NSC. As a conclusion, NSC have UPE-properties and the intensity is increased by serial passaging that are significant in the sixth passage. The AgNPs increases the UPE intensity of NSC that pushes more differentiation of NSC to the neurons. The mirror was not effective in enhancement of UPE. As a result, UPE measurement may be suitable for assessing and studying the effects of nanoparticles in living cells and neurons.This work was supported by grant No. 94-01-01-10157 from Shiraz University of Medical Sciences, Shiraz, Iran. This article was a part of the thesis written by Esmaeil Fereydoni, MSc. student of Anatomy

Risk stratification of diabetic patients with unusual cardiac symptoms using a myocardial perfusion scan

Background: Autonomic nervous system dysfunction in diabetic patients can result in an atypical presentation of cardiovascular disease that can be missed. We aimed to use single-photon emission computed tomography (SPECT) to assess cardiovascular disease (CAD) in diabetic patients with atypical pain to determine whether the pain above reflects the CAD. Methods: Diabetic patients with atypical cardiac symptoms were referred to the SPECT department. Demographic data such as age, gender, diabetes status, and other underlying diseases were gathered. A myocardial perfusion scan was then performed. The results were recorded to evaluate the risk of myocardial ischemia and the degree of coronary artery involvement in a non-invasive manner. Results: The study included 222 (177 female) subjects with mean ages of 63.01±11.62 and 59.41±9.19 in positive and negative SPECT, respectively. The most common symptoms were atypical chest pain (51.8%), followed by shortness of breath (50.5%), nausea, and syncope (0.9%). Cardiac parameters, such as the summed stress score (SSS), summed rest score (SRS), total perfusion deficit in stress (TPD-s), total perfusion deficit in rest (TPD-r), were significantly higher in the group with coronary artery involvement (P<0.001). However, ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volumes (ESV) parameters were not (P=.0.328, 0.351, and 0.443, respectively).Conclusions: The mere presence of diabetes does not necessitate any additional diagnostic tests beyond those required for the general population, and it is possible to follow a diagnostic course similar to that of the general population

Strategies in Development of Iranian Medical Sciences Universities for Dynamic Presence in the International Arena

Background & Objective: In compatibility with the progress of universities and expansion of knowledge and science around the world, Iran has also had significant academic progress in recent years. However, the vision of Iran for the following decades is very ambitious. Much has to be achieved to reach the highest position in the region in development, economy, science, and technology. This qualitative study was designed to explore the strengths and weaknesses of universities. Methods: This qualitative study had three phases. In the first phase, we explored the topic in brain storming sessions. Then, the themes raised in phase one were discussed deeply in unstructured interviews with selective experts around the country. In the last phase, we asked 30 selective academic staff from different medical sciences universities to categorize the issues based on their importance and their solutions using Delphi method. Results: Our findings showed that improvement of international affairs were frequently stressed by our respondents. In this domain, the English skills of academic staff and students, big revision in rules and regulations, and encouraging the establishment of close scientific communication with academic organizations around the world were highlighted. In addition, most respondents believed that problems were understandable, but our main conflicts were in finding applicable solutions and implementing decisions. Conclusion: Our results showed that for a better presentation of Iranian universities in the international environment a new approach to long term reform programs is necessary. In this plan, special attention must be paid to the educational and research infrastructures. Keywords University ranking University of Medical Sciences Development strategies International arena Critical thinking Skills Medical student

The Role of Social Media, Transparency and Social Responsibility in Promoting Business Performance of Travel and Tourism Services Companies

Nowadays, social media has revolutionized business. Not only in the virtual world these media have attracted many customers and have given new impetus to industries and products, but also they are a place for corporate relationships and marketing activities. On the other hand, corporate social responsibility has evolved in recent years, along with social, political, and business development and has been considered by companies. The internal function of social responsibility can improve the company's position and, ultimately, increase profitability and lead to long-term survival. Therefore, the purpose of this research is to study the impact of social media, transparency and social responsibility on performance by explaining the intermediary role of brand sustainability. The statistical population of this study is managers of travel and tourism services companies in Tehran. To obtain sample size, simple random sampling method and Cochran formula have been used. In this research, library and field methods are used to collect information. In terms of the purpose this is an applied research and in terms of data collection method, this is of descriptive and correlational research type. Confirmatory factor analysis and structural equation modeling were used to analyze the data. The results of the research show that social media, transparency and social responsibility through brand sustainability have a significant effect on business performance. Also, the results showed that the intermediary effect of the sustainable brand was significant

Stereological study of the effect of ginger's alcoholic extract on the testis in busulphan-induced infertility in rats

Background: In traditional medicine zingiber officinale used to regulate female menstural cycle and treat male infertility. Recent studies have suggested the possible role of ginger extract in improving the testicular damage of busulfan. Objective: The aim of this study was to evaluate the effects of zingiber officinale on the sperm parameters, testosterone level and the volume of the testes and seminiferous tubules by stereological methods. Materials and Methods: Fifty rats were divided into four groups. All the rats were given a single intraperitoneally injection of 5mg/kg busulfan solution. The first group was kept as busulfan control, while the other groups were orally administrated ginger extract in graded doses of 50, 100 and 150mg/kg b.wt, for 48 consecutive days. At the end, all animals were anesthetized and their testes and vas deference were removed, fixed, embedded, and stained. The volume of testes and seminiferous tubules were estimated by cavalieri methods. Results: The result showed, that zingiber officinale increased the volumes of seminiferous tubule in 100mg/kg treated group compared to control group. Sperm count (706×105 and 682×105) and the level of testosterone (50.90 ng/mL and 54.10 ng/mL) enhanced in 100 mg/kg and 150 mg/kg treated groups compared to control group (p=0.00). Conclusion: It seems that zingiber officinale stimulate male reproductive system in induce busulfan infertility

Stereological study of the effect of ginger's alcoholic extract on the testis in busulfan-induced infertility in rats

Background: In traditional medicine zingiber officinale used to regulate female menstural cycle and treat male infertility. Recent studies have suggested the possible role of ginger extract in improving the testicular damage of busulfan. Objective: The aim of this study was to evaluate the effects of zingiber officinale on the sperm parameters, testosterone level and the volume of the testes and seminiferous tubules by stereological methods. Materials and Methods: Fifty rats were divided into four groups. All the rats were given a single intraperitoneally injection of 5mg/kg busulfan solution. The first group was kept as busulfan control, while the other groups were orally administrated ginger extract in graded doses of 50, 100 and 150mg/kg b.wt, for 48 consecutive days. At the end, all animals were anesthetized and their testes and vas deference were removed, fixed, embedded, and stained. The volume of testes and seminiferous tubules were estimated by cavalieri methods. Results: The result showed, that zingiber officinale increased the volumes of seminiferous tubule in 100mg/kg treated group compared to control group. Sperm count (706×105 and 682×105) and the level of testosterone (50.90 ng/mL and 54.10 ng/mL) enhanced in 100 mg/kg and 150 mg/kg treated groups compared to control group (p=0.00). Conclusion: It seems that zingiber officinale stimulate male reproductive system in induce busulfan infertilit

Abroad Travelers Knowledge, Attitudes and Practice regard AIDS, Hepatitis B and Influenza

Introduction:&nbsp; Constantly number of travelers are growing and they are&nbsp; exposed to superimpose disease risks it&rsquo;s morbidity caused by endemic disease of their destination. International travel are the major cause of infectious disease outbreak. Asia-Oceaninca have growing number of tourist. Deficiency of information on Travelers knowledge, attitudes and practice regarding infectious disease is concerned. This survey was conducted in order to assess travelers knowledge, attitudes and practice regard AIDS, hepatitis B and Influenza. Methods: this study is a descriptive cross-sectional which was conducted among travelers in Imam Khomeini airport. Simple random sampling was used. Data were collected through standard questionnaire. Collected data was analyzed by SPSS-16 and statistics test such as Anova, T test, cross tab, correlation, regression. Results: the mean age of participants was 34.66&plusmn; 10.31. Education level of 47.3 percent of travelers was college and a bachelor's degree. highest rate of travelers knowledge were regarding AIDS 81.5% and Influenza 80%, in while knowledge regard hepatitis B was lower(48.5%). Highest rate of travelers practice was&nbsp; related to AIDS. Conclusion: attention to this survey results of intermediate knowledge and practice, fine attitudes and concern to international travel cause transmitting of diseases and their epidemy , it&rsquo;s recommended&nbsp; in order to educate travelers to abroad via curriculum, poster, pamphlet , radio, TV , an urgent measure should be taken