Investigating the role of temperature on thermal stress and fracture propagation in geothermal systems

Available geothermal energy extractable by conventional techniques is in dry and comparatively impermeable rocks. Enhanced Geothermal System (EGS) technologies enhance geothermal resources in the hot dry rock (HDR) through fracture operations, usually through hydro-shearing. Large scale deployment of geothermal power production requires the demonstration of successful EGS projects extracting heat from reservoirs constituting a variety of geological conditions. In this part, numerical models are very important to show how geothermal power plant operations can be less risky and safer. Owing the fact that, some major challenges in these operations are interaction between shear and tensile fractures with natural faults. These interactions can be seen in two different cases, either these faults are badly oriented or these faults are fill in pore fluids or gases which are mainly high pressure. Fluids and gases are important on account for because of the fact that these pore fluids can over whelmed the injection pressure and cause well blow out. Furthermore, to prevent these operational hazards, we use field data and analysis in combination with experimental tests and numerical/analytical models with finite element method software such as COMSOL Multiphysics. Further work will be required for improving enhanced geothermal production by optimizing hydro-shearing practices

The role of hemodialysis machines dedication in reducing Hepatitis C transmission in the dialysis setting in Iran: A multicenter prospective interventional study

BACKGROUND: Hepatitis C virus (HCV) infection is a significant problem among patients undergoing maintenance hemodialysis (HD). We conducted a prospective multi-center study to evaluate the effect of dialysis machine separation on the spread of HCV infection. METHODS: Twelve randomly selected dialysis centers in Tehran, Iran were randomly divided into two groups; those using dedicated machines (D) for HCV infected individuals and those using non-dedicated HD machines (ND). 593 HD cases including 51 HCV positive (RT-PCR) cases and 542 HCV negative patients were enrolled in this study. The prevalence of HCV infection in the D group was 10.1% (range: 4.6%– 13.2%) and it was 7.1% (range: 4.2%–16.8%) in the ND group. During the study conduction 5 new HCV positive cases and 169 new HCV negative cases were added. In the D group, PCR positive patients were dialyzed on dedicated machines. In the ND group all patients shared the same machines. RESULTS: In the first follow-up period, the incidence of HCV infection was 1.6% and 4.7% in the D and ND group respectively (p = 0.05). In the second follow-up period, the incidence of HCV infection was 1.3% in the D group and 5.7% in the ND group (p < 0.05). CONCLUSIONS: In this study the incidence of HCV in HD patients decreased by the use of dedicated HD machines for HCV infected patients. Additional studies may help to clarify the role of machine dedication in conjunction with application of universal precautions in reducing HCV transmission

Dental caries in primary and permanent teeth in children's worldwide, 1995 to 2019: a systematic review and meta-analysis

Background: Early childhood caries (ECC) is a type of dental caries in the teeth of infants and children that is represented as one of the most prevalent dental problems in this period. Various studies have reported different types of prevalence of dental caries in primary and permanent teeth in children worldwide. However, there has been no comprehensive study to summarize the results of these studies in general, so this study aimed to determine the prevalence of dental caries in primary and permanent teeth in children in different continents of the world during a systematic review and meta-analysis. Methods: In this review study, articles were extracted by searching in the national and international databases of SID, MagIran, IranMedex, IranDoc, Cochrane, Embase, ScienceDirect, Scopus, PubMed, and Web of Science (ISI) between 1995 and December 2019. Random effects model was used for analysis and heterogeneity of studies was evaluated by using the I2 index. Data were analyzed by using the Comprehensive Meta-Analysis (Version 2) software. Findings: In this study, a total of 164 articles (81 articles on the prevalence of dental caries in primary teeth and 83 articles on the prevalence of dental caries in permanent teeth) were entered the meta-analysis. The prevalence of dental caries in primary teeth in children in the world with a sample size of 80,405 was 46.2% (95% CI: 41.6–50.8%), and the prevalence of dental caries in permanent teeth in children in the world with a sample size of 1,454,871 was 53.8% (95% CI: 50–57.5%). Regarding the heterogeneity on the basis of meta-regression analysis, there was a significant difference in the prevalence of dental caries in primary and permanent teeth in children in different continents of the world. With increasing the sample size and the year of study, dental caries in primary teeth increased and in permanent teeth decreased. Conclusion: The results of this study showed that the prevalence of primary and permanent dental caries in children in the world was found to be high. Therefore, appropriate strategies should be implemented to improve the aforementioned situation and to troubleshoot and monitor at all levels by providing feedback to hospitals

Conceptual approach to body fluids and edema, education determines clinical outcomes in nephrotic syndrome management

The objective of our paper is to reemphasize the importance of critical thinking in clinical practice and education in the field of internal medicine using the example of edema. We provide an in-depth and interactive investigation of physiological concepts as a foundation for the understanding of body fluid dynamics. Four fundamental concepts described are the hydrostatic and oncotic pressure gradients, capillary permeability, and lymphatic drainage. Furthermore, we visit the causes of edema in nephrotic syndrome. Traditional teaching considers hypoalbuminemia as a primary cause of edema formation in nephrotic syndrome. It has been proven that other etiologies causing edema include salt and water retention by the kidneys and a possible increase in capillary permeability are more important causes in the development of edema in nephrotic syndrome. © 2021, Iranian Society of Nephrology. All rights reserved

Early detection of patients at risk of acute renal failure after natural disasters

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Epidemiologic aspects of the Bam earthquake in Iran: the nephrologic perspective

Background: Acute renal failure is a serious, preventable, and potentially reversible midterm complication after mass disasters. In 2003, an earthquake struck Bam, Iran. This article studies the epidemiologic aspects of the earthquake from a nephrologic perspective. Methods: A questionnaire was sent to the reference hospitals. The resulting database of 2,086 traumatized patients hospitalized in the first 10 days was analyzed. Results: Mean age was 29.0 +/- 15.6 years. Compared with the resident population, the percentage of patients was lower among children and teenagers younger than 15 years and higher among young and middle-aged adults (P<0.001). There was no significant difference between mean ages of patients with acute renal failure and other patients. Time under the rubble was longer for patients with acute renal failure (6.2 +/- 4.1 versus 2.1 +/- 3.9 hours; P<0.001). These patients were hospitalized later (3.1 +/- 2.8 versus 1.5 +/- 1.7 days after the disaster; P<0.001) and longer (16.7 +/- 12.8 versus 12.5 +/- 11.3 days; P<0.001). Sepsis (11.6% versus 0.5%), disseminated intravascular coagulation (7.3% versus 0.3%), adult respiratory distress syndrome (9.1% versus 1.4%), fasciotomy (38.9% versus 1.9%), amputation (6.1% versus 0.5%), and death (12.7% versus 1.9%) were markedly more frequent among patients with acute renal failure (P<0.001 for all). Conclusion: Hospitalized patients were mostly young and middle-aged adults. Patients with acute renal failure were entrapped longer and hospitalized later and for longer periods. Medical complications, surgical procedures, and mortality were greater in the latter group. Early extrication and quick hospitalization with appropriate multidisciplinary care are cornerstones to prevent acute renal failure and Its subsequent mortality In earthquake conditions