394 research outputs found
Identification and Pluripotency of Mouse Spermatogonial Stem Cells
Spermatogonial stem cells (SSCs) are located on the basal membrane in seminiferous tubules of the testis and are responsible for sperm production during the male’s life. Although the morphology and kinetics of spermatogonia has been extensively characterized, there is still a lack of specific cellular, morphological and biochemical criteria for SSCs. However, Fluorescence-activated cell sorting (FACS), magnetic-activated cell sorting (MACS), matrix selection and morphology-based selection are some of the useful methods for the isolation of SSCs.
In the current study, we demonstrated that using cell sorting approaches are dispensable for the generation of mouse SSCs cultures. We identified a simple and highly reproducible protocol for the isolation of SSCs with morphology-based selection and successfully established two types of SSCs (Type I and Type II). Using co-culture systems with different mitomycin-C treated feeder layers in long-term culture, we established the optimal conditions for the cultivation and gene expansion of these two types of SSCs. We successfully expanded Type I SSCs on mouse embryonic fibroblasts (MEFs) and Type II SSCs on both SNL and primary testicular stroma cells (TSCs) feeders. Electron microscopic analysis revealed that Type I SSCs display a similar morphology with SSCs in-vivo high nucleus/cytoplasm ratio, while Type II SSCs have a different morphology small nucleus/cytoplasm ratio. Immunocytochemistry, FACS and Fluidigm real-time RT-PCR results showed that Type I SSCs clearly express germ cells markers while Type II SSCs only partially express the typical germ cell profile of SSCs. Following the transplantation of Type II SSCs to busulphan-treated NOD/ SCID mice, we observed a localization of GFP-labeled cells in the basal compartment of the seminiferous tubule. Furthermore, GFP labeled sperms were detected in epididymis. Among the most obvious molecular differences between Type I and Type II SSCs were their reprogramming capacity to mouse embryonic stem cells-(ES-) like cells that occurred only on the critical time window after initiation of Type I SSCs culture. Although testis-derived ES-like cells have been obtained in several studies, the time window for the shift to pluripotency was not clearly determined. In our experiments, we observed that the spontaneous appearance of germline-derived ES-like cells from both neonate and adult Type I cells occurred only during a special time window (41 until 125 days) after initiation of Type I cells from neonate and adult promoter-reporter Oct4-GFP transgenic mice. The generated ES-like cells expressed pluripotency markers, differentiated into all three germ lineages, formed complex teratoma after transplantation in SCID mice and produced chimeric mice. Although the exact mechanism of the development of ES-like cells from GSCs is still unclear, this new information could provide an ideal strategy for scheduling natural conversion mechanisms of ES-like cells from mouse testes. Therefore, the two different types of SSCs could provide an ideal cell system for studying both pluripotency and in-vitro differentiation of SSCs to sperm and also provide a new strategy for isolation of SSCs from neonatal and adult mice by morphology-based selection
Automatic Identification of Personal Automobiles Plates of Iran Using Genetic Algorithm
In this study, a new method for using LPR systems for Iranian plates number has been presented. Increasing the precision of the letter recognition process and reducing the amount of training are in fact the main advantages of the new hybrid model. The K-NN has been implemented as the first classification method, because it was simple, and it was resistant to the noisy data, and for large datasets it is also effective at zero cost. The confusion problem related to the similarity of letters in plate numbers has also been resolved by using the classification model of the multi-class genetic algorithm. The genetic algorithm improves K-NN performance in the recognition of similar letters. Vehicle license plate recognition (LPR) plays an important role in ITS and is mainly used in access control systems.The purpose of this research is to determine the Iranian plate automobiles that are specifically owned by the automobile. The confusion caused by the similarity between the letters of the alphabet and numeric characters is one of the problems of the Persian LPR systems at the diagnostic stage. In this regard, a method using the KNN-based advantages of genetic algorithm as a hybrid model is presented in this study to overcome the above problem. The genetic algorithm has been trained and tested only with the same letters, thus the cost of training for the genetic algorithm has significantly decreased. Comparison of the results obtained from the experiments carried out in this study with the results of a similar study shows that the combined KNN-genetic algorithm model significantly improved the detection rate of the letters for all tested cases from 94% to 97.03% . Keywords: Coding, plate recognition, genetics, Iran automobile, Genetic Algorithm DOI: 10.7176/CEIS/10-6-04 Publication date:July 31st 2019
Zooarchaeology of the Pre-Pottery and Pottery Neolithic site of Qasr-e Ahmad (Iran)
The zooarchaeological study of the Neolithic site of Qasr-e Ahmad in Fars Province (southern Zagros, Iran) provides valuable evidence for a better understanding of the process of caprine domestication and dispersal in Southwest Asia.Goat was the most commonly exploited animal in Qasr-e Ahmad during both phases of prehistoric settlement (Pre-Pottery Neolithic and Pottery Neolithic). Sheep were also present but represent a limited contribution to the subsistence economy at the site. Limited osteometric data from sheep suggest that they were already domesticated at the site, which is earlier than hitherto suggested for the region. Kill-off and osteometric data indicate that the majority of goats and sheep were managed using strategies known at other later sites in the region. Cattle and pig were not domesticated and were not regularly exploited. The location of the site next to the Qara Aqhaj permanent river, the presence of architectural remains in the PPN phases of the site, as well as the abundance of lithic tools indicate pastoral and agricultural components in the Qasr-e Ahmad human communities
Studying Brand Equity in Terms of Beliefs Shaping Consumers’ Attitudes on Advertising through Mobile Phones
Any innovation creates new opportunities and in recent years, advertising has experienced radical changes due to technological progresses. Mobile phone is a type of such technological changes which has converted into an important advertising channel. Regarding such importance, present study is conducted to promote three aims. The first aim of this research is to identify beliefs which shape audiences’ attitudes on mobile advertising. The second aim is that this research evaluates the impact of those identified beliefs which shape an attitude on mobile advertising on a general attitude on advertising. The ultimate aim is to study the impact of the attitude on advertising on brand equity. Present study is a survey which uses questionnaire to collect data. To achieve the aims of this research, 384 users of Irancel’s products and services who were exposed by mobile advertising as the sample. To analyze data and to test research hypotheses and model, structural equation modeling (SEM) and confirmatory factor analysis (CFA) were used. Research findings show the significant impact of such beliefs as “being informative”, “good for economy”, “hedonism”, “annoyance factor”, “validity”, “personalization” and “permission” in mobile advertising on “attitude on advertising” and the significant impact of “attitude on mobile advertising” in “brand equity”. Keywords: Advertising, Mobile Advertising, Attitudes on Mobile Advertising, Brand Equit
Active Damping of Torsional Vibrations due to the Sub-harmonic Instability on a Synchronous Generator
Presenting an Integrated Model of Demetel Method and Fuzzy Hierarchical Analysis Process to Identify and Prioritize the Factors Affecting the Quality of Financial information in the Public Sector Based on the Grounded Theory Approach
The main purpose of this study was to present an integrated model of Dimtel method and fuzzy hierarchical analysis process in order to identify and prioritize the factors affecting the quality of financial information in the Iranian public sector using the grounded theory approach. The present study was of applied and exploratory type. To determine the sample size, the snowball method was utilized, based on which the statistical sample size of 70 people was considered. To achieve the research objectives, the questions to be designed for the interviews and finally the 5 structural factors of environment, process, output, outcome, and sub-component related to each factor were identified as effective factors in financial information quality based on the grounded theory approach. Then, the combined model, fuzzy hierarchical analysis, and fuzzy Dimtel were applied to prioritize, determine the impact intensity and effectiveness, and draw a causal diagram between the components. The results showed that among the main factors of the research, the structural factor gained the highest rank and the factor of process was the least important factor in the quality of financial information in the public sector. IntroductionThe expansion of the duties, activities and programs of the governments has caused the use of a coherent and integrated government accounting and financial reporting information system to carry out public sector financial affairs and make logical and useful decisions to achieve organizational goals and fulfill the responsibility of accountability. Therefore, in recent years, there have been many developments in the accounting and financial reporting system of the public sector in developed and sometimes developing countries.In this regard, in recent years, in Iran, due to the growing economic, social, and cultural environment and the communication of the general strategies of the twenty-year vision document and the fourth and fifth programs of the country's economic, social, and cultural development, and following that, changing the budgeting system from a program The need to calculate the cost of government services and activities, the need to make fundamental changes in the accounting and financial reporting system of the public sector is clearly felt; Therefore, measures have recently been taken in the field of reforming the country's financial system, the turning point of which is the formulation of accounting standards for the public sector and the theoretical concepts of public sector financial reporting, which became effective at the beginning of 2014 (Kazazi, 2005).In fact, providing high-quality information about public sector activities by using the optimal public sector accounting system increases the usefulness of the information provided in financial reports for users and makes it possible to achieve the goals of financial reporting, including accountability and decision-making (Kordestani and Nasiri, 2018). Obviously, the implementation of a high-quality financial reporting system in the public sector will be accompanied by serious obstacles and challenges in the early years; Therefore, it is essential to identify obstacles, challenges and factors affecting the quality of financial reporting in the public sector.Therefore, in this research, an attempt was made to provide a more comprehensive criterion by using more observable criteria of the quality of public sector financial reporting, which also have theoretical support, and to answer the following question:What are the factors affecting the quality of financial reporting in the public sector? Methods & MaterialThe present research method is of mixed type. The mixed research approach is a type of research method in which the researcher combines the elements of quantitative and qualitative approaches in order to reveal the existing obstacles and deeply understand the phenomena. In order for the combination of two approaches (quantitative and qualitative) to take place in the most effective way, the researcher must combine different data in such a way that not only they do not overlap, but in the results, the strengths are strengthened and the weaknesses are eliminated (Mohammadi et al., 2019).In the qualitative part of the research, first the indicators are identified through interviews and using the method of grounded theory. In this section, the aim is to identify the components related to the quality of financial information of the public sector and extract the relevant categories.In the quantitative part of the research, the relationships between the categories and indicators obtained from the qualitative part are analyzed by the combined method of fuzzy hierarchical analysis and Fuzzy Dimetal technique 4. In this way, the fuzzy hierarchical analysis process approach was used to prioritize the quality components of public sector financial information, and finally, by using the fuzzy Dimetal model, the cause-effect diagram between the components was presented. FindingIn the grounded theory method, after collecting the interview and textual data, analysis and coding have been done in three stages of open, central and selective coding; Therefore, in this research, based on the grounded theory method and after performing the steps of open, central and selective coding, the factors extracted from library sources, literature review and collective opinion of experts were categorized into 5 structural factors, environment, processes, output and consequences.The results of the combination of two methods, fuzzy hierarchy and fuzzy Dimethal, are presented in Table 7. According to the results of Table 7, the order and prioritization of the mentioned factors are as follows. In the structural factor, the infrastructure component in the public sector has the highest weight in the hierarchical analysis, and it also has the highest rank in the fuzzy Dimetal method and is in maximum interaction with other components; Therefore, due to its greater effectiveness, it is considered a disabled criterion. In the environmental factor, the component of technological changes has the highest weight in the hierarchical analysis, and it has the highest rank in the Fuzzy Dimetal method and is in the maximum interaction with other components; Therefore, due to its greater effectiveness, it is considered a disabled criterion. In the factor of processes, the component of not fully implementing operational budgeting has the highest weight in the hierarchical analysis, and in the Fuzzy Dimtel method, it interacts with other components in a low way and ranks twelfth; But due to its greater impact on other components, it is considered causal. In the output factor, the quick response component has the highest weight in the hierarchical analysis and the highest rank in the fuzzy Dimetal method, which shows that this component has the most interaction with other components and is considered a causal criterion due to its high impact on other components. In the effect factor, the component of selecting capable managers is in the first rank of the hierarchical analysis, and it has the highest rank compared to other components in the Fuzzy Dimtel method, and it is more effective than other components; Therefore, it is considered a disabled criterion. Results & ConclusionIn order to achieve the goals of the research, first the research literature has been reviewed and the questions for the interview have been designed. Then, using the grounded theory method, 5 structural, environmental, processes, output and consequence categories and their sub-components were identified as factors affecting the quality of public sector financial information. Further, considering the importance of the issue and determining the importance of each of the factors affecting the quality of financial information of the public sector, this research prioritized the mentioned factors with the approach of fuzzy hierarchical analysis. The final result of prioritization showed that the process factor is the least important factor in the quality of financial information in the public sector, and structural factors have been determined as the most important factor in the quality of financial information. This result shows that the structures of the public sector are currently not desirable in Iran and have problems and ambiguities.The combination of the results of the combination of fuzzy hierarchical analysis and fuzzy Dimetal showed that among the structural factors, the infrastructure component in the public sector has the highest weight and rank in the hierarchical analysis and fuzzy Dimetal method. This result indicates that from the point of view of the respondents, infrastructure is necessary and important to achieve high-quality financial reporting in the public sector. In the environmental factor, the component of technology changes has the highest weight and rank in hierarchical analysis and fuzzy Dimetal method. The significant development of information technology and its benefits make a lot of information available through the public database, especially the Internet, and as a result, decision makers can increasingly use more timely and relevant information to make decisions. This interpretation is in line with the result that from the point of view of the respondents, the component of technological changes has the highest rank among the environmental factors. In the factor of processes, the complete non-implementation of operational budgeting has the highest weight in the hierarchical analysis and in the Fuzzy Dimtel method, it has a low interaction, which shows that this component has a strong interaction with other components and is considered a causal criterion due to its high impact on other components.In the output factor, the component of quick response from the point of view of the respondents is in the first rank of hierarchical analysis and fuzzy Dimetal method. Based on the strategies proposed by the respondents to improve the quality of financial reporting, it is expected that this strategy (accountability) will bring the highest result for the quality of financial reporting of the public sector. Obviously, from the point of view of the respondents, the existence of high-quality financial information in democratic systems plays a major role in fulfilling the government's duty as public accountability; Because it is used as a tool to evaluate accountability and make economic, social and political decisions by people
Undifferentiated and Differentiated Spermatogonial Stem Cells
Spermatogenesis is initiated and sustained by a rare population of singular spermatogonial stem cells (SSCs). These SSCs are connected to the basement membrane of the seminiferous tubules and possess distinctive morphological characteristics. They serve as a vital foundation for a robust stem cell system within the testis, crucial for spermatogenesis and reproductive processes. The isolation and cultivation of human SSCs would significantly enhance our understanding of germ and stem cell biology in humans. Although a challenging endeavor, the recent advancements in enriching and propagating spermatogonia carrying the male genome offer a significant stride toward future transplantation and the restoration of fertility in clinical settings
A Look at the Life and Career of Dr. Karim Vessal, The Professor of Shiraz Medical School and a Pioneer in Medical Journalism
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The liver-derived exosomes stimulate insulin gene expression in pancreatic beta cells under condition of insulin resistance
Introduction: An insufficient functional beta cell mass is a core pathological hallmark of type 2 diabetes (T2D). Despite the availability of several effective pharmaceuticals for diabetes management, there is an urgent need for novel medications to protect pancreatic beta cells under diabetic conditions. Integrative organ cross-communication controls the energy balance and glucose homeostasis. The liver and pancreatic islets have dynamic cross-communications where the liver can trigger a compensatory beta cell mass expansion and enhanced hormonal secretion in insulin-resistant conditions. However, the indispensable element(s) that foster beta cell proliferation and insulin secretion have yet to be completely identified. Exosomes are important extracellular vehicles (EVs) released by most cell types that transfer biological signal(s), including metabolic messengers such as miRNA and peptides, between cells and organs. Methods: We investigated whether beta cells can take up liver-derived exosomes and examined their impact on beta cell functional genes and insulin expression. Exosomes isolated from human liver HepG2 cells were characterized using various methods, including Transmission Electron Microscopy (TEM), dynamic light scattering (DLS), and Western blot analysis of exosomal markers. Exosome labeling and cell uptake were assessed using CM-Dil dye. The effect of liver cell-derived exosomes on Min6 beta cells was determined through gene expression analyses of beta cell markers and insulin using qPCR, as well as Akt signaling using Western blotting. Results: Treatment of Min6 beta cells with exosomes isolated from human liver HepG2 cells treated with insulin receptor antagonist S961 significantly increased the expression of beta cell markers Pdx1, NeuroD1, and Ins1 compared to the exosomes isolated from untreated cells. In line with this, the activity of AKT kinase, an integral component of the insulin receptor pathway, is elevated in pancreatic beta cells, as represented by an increase in AKT’s downstream substrate, FoxO1 phosphorylation. Discussions: This study suggests that liver-derived exosomes may carry a specific molecular cargo that can affect insulin expression in pancreatic beta cells, ultimately affecting glucose homeostasis
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