Experimental and PFC2D numerical study of progressive shear behaviour of single rough rock fractures

This thesis investigates the progressive shear behaviour and asperity degradation of single rough rock fractures using 2D numerical simulations and laboratory experiments.The particle flow code (PFC) was chosen for simulation purposes in this work. The fracture and intact sample are modelled as an assembly of circular disks in PFC2D. By performing biaxial test simulations in PFC2D, correlations were obtained between micro and macro properties of the intact sample. These results were used later for guidance to establish the micro properties of models corresponding to mortar samples, based on the macro response obtained from the lab experiments. To define a set of micro properties corresponding to fracture particles and investigate their effects on shear behaviour of both planar and rough fractures, a sensitivity analysis of fracture model micro properties including particle size, particle friction coefficient, and contact bond strength were carried out.Several synthetic profiles with triangular and sinusoidal geometries were simulated to study their shear behaviour. A prior knowledge of the shearing response of such simple geometries allowed calibration of the model to be made. The results confirmed the observation of different failure modes, i.e. sliding, asperity cut-off, and degradation, as a result of increasing the normal stress. The simulation results were compared with lab experiments that were carried out on synthetic samples with constant height elevations along their thickness. This was the closest geometry that could be used to calibrate 2D models, and a good agreement was found between the results of the two approaches.The lab shear tests were conducted using a fracture shear cell (FSC). This was a special set up made from modifications on an existing triaxial stress cell. The FSC was capable of applying large shear and normal loads to the sample where the normal load was applied in a constant rate using a pressure cylinder.Both lab experiments and simulations were performed on pseudo-real as well as rock-like fracture specimens. The directionality in shear strength when the sample was sheared in opposite directions along a horizontal plane was also studied. The 1D Riemannian dispersion parameter (DR1) was determined for different profiles’ geometries as a measure of roughness. This parameter showed a good correlation with the profile’s shear strength. The spline fits to the peak shear strength data for triangular profile geometry as well as the number of rock fracture profiles obtained from literature were developed and presented. A detailed discussion on the simulations and lab experiments will be given and the results presented and interpreted

The Pattern for Formulation of Cinema Problems of Iran from the Perspective of the Supreme Leader, from current situation to the favorable situation

Cinema, despite its sublime artistic dignity and influence, has not been able to meet the needs of the Islamic Revolution of Iran even after more than three decades after the revolution. Lack of policy-making is one of the reasons for the status quo of cinema. Proper policy-making in an area is the result of properly distinguishing problems which arise from the gap between the current situation and the desired situation. The present study seeks to plot the current and the desired situation of cinema and to design a pattern for the formulation of cinema problems by analyzing the statements of the Supreme Leader of the revolution, as the chief policy maker of the country, considering the existing gap in the two situations. The most important findings of this research, obtained by Thematic Analysis, indicate that intentionally wrong entering of the cinema to the country from day one, the opposition’s performance at the cultural front, and the lack of work, by artists and authorities of the own front, has caused numerous problems at three levels of the cinema, the theme, the form, and experts. However, the main concern, in the supreme leader's opinion regarding creating the Islamic cinema, is the quantitative and qualitative enhancement of the believer and revolutionary artists and the provision of the  opportunity for them to emerge while other problems in that regard must be understood and prioritized in relation to the said concern.

Immune Response to SARS-CoV-2 Vaccine among Heart Transplant Recipients: A Systematic Review

BACKGROUND: Heart transplant (HTX) recipients are at a significantly higher risk of adverse clinical outcomes, due to chronic immunosuppression and co-existence of other chronic conditions, when contracting the SARS-CoV-2 infection. Although vaccination against SARS-CoV-2 is currently the most promising measure for the prevention of severe Coronavirus Disease 2019 (COVID-19) among solid organ transplant recipients, the extent of immune response and its protective efficacy among patients receiving HTX has not been sufficiently studied. METHODS: We performed a systematic review of the literature by inquiring PubMed/Medline to identify original studies among HTX recipients, who had received at least one dose of the SARS-CoV-2 vaccine. Data on the measured humoral or cellular immune response was collected from all the eligible studies. Factors associated with a poor immune response were further investigated within these studies. RESULTS: A total of 12 studies comprising 563 HTX recipients were included. The average age of the study participants was 60.8 years. Sixty four percent of the study population were male. Ninety percent of the patients had received an mRNA vaccine (Pfizer/ BNT162b2 or Moderna/mRNA-1273). A positive immune response to SARS-CoV-2 vaccine was variably reported in 0% to 100% of the patients. Older age (\u3e 65 years), vaccine dose (first, second, or third), time since HTX to the first dose of the vaccine, the time interval between the latest dose of the vaccine and measurement of the immune response, and the type of immunosuppressive regimen were all indicated as potential determinants of a robust immune response to the SARS-CoV-2 vaccination. CONCLUSION: HTX recipients demonstrate a weaker immune response to the vaccination against SARS-CoV-2 compared to the general population. Older age, anti-metabolite agents such as mycophenolate mofetil, and vaccination during the first year following the HTX have been indicated as potential determinants of a poor immune response

Is Shunt Location a Risk Factor for the Development of De Novo Post-shunt Seizures?

Background: While ventriculo-extracranial shunting procedures have been the standard treatment option for hydrocephalus for a long time, their long-term morbidity, including the development of post-shunt de Novo seizures, should be taken into account. This study aimed to investigate the rate and risk factors of the occurrence of de Novo post-shunt seizures in patients with hydrocephalus. Methods: In this retrospective longitudinal study, all patients with hydrocephalus who had ventriculo-peritoneal shunt insertion from 2014 to 2017 at Namazi Hospital, (Shiraz, Iran) were studied. Phone calls were made to all patients to obtain their postoperative seizure outcome and other data (e.g., sex, age at surgery, shunt insertion location, history of seizures before surgery, history of seizures after surgery, any other type of brain surgery, and the etiology of their hydrocephalus). The Pearson Chi Square was used for the analysis of binary variable (e.g., sex) differences, and the t test for the analysis of differences in the means of numerical variables (e.g., age). Bonferroni correction tests were also utilized. P values less than 0.05 were considered significant. Results: A total of 114 patients were included in the study. Overall, 68 (60%) patients had a frontal location of shunt insertion and 46 (40%) had a parietal site. Twenty-four (21%) patients reported experiencing de Novo post-shunt seizures, 15 of which had a frontal location and nine a parietal location for shunt insertion (P=0.824). Conclusion: De Novo post-shunt seizures are common occurrences. However, shunt location is not a significant risk factor for the development of de Novo post-shunt seizures

Investigation of the effect of education on nutritional knowledge, attitude and performance of primary school students in Ilam - 2015

Background and objective: Nutritional habits are formed in childhood and will remain until the end of life. Proper nutrition in childhood leads to the promotion of growth and development of child and reduces the risk of chronic diseases during adulthood. This study aimed to assess the effect of education about nutrition on nutritional knowledge, attitude and performance of students in primary schools. Methods: This is a quasi-experimental study which is conducted in 2015. 180 students from primary school in Ilam city were selected randomly and assigned into case (90 people) and control (90 people) groups. Before initiation of educations, a pretest was held in both groups. Then for the case group, a nutritional education was performed during 5 sessions of 45 minutes. After 2 weeks of finishing the educational sessions, posttest was performed by giving a questionnaire of knowledge, attitude and performance to case and control groups. Eventually, two groups were compared with each other in terms of nutritional knowledge, attitude and performance. In order to analyze the collected data, SPSS 21 software was used. The significance level of tests was 5% and descriptive statistics including tables and numeric indices and also inferential tests including paired t-Test, independent t-Test and Chi-square were used. Results: Findings of this study showed that in the case group, there was a statistically significant difference between the mean score of knowledge, attitude and performance of students before and after education (P 0.05). There was also a significant difference between case and control groups after education (P< 0.05). Conclusion: Nutritional education may lead to the improvement of nutritional knowledge, attitude and performance of primary school students. Considering the importance and role of students and also low cost of preventive measures in comparison with therapeutic measures, it looks necessary to expand this type of educational program

Evaluation of serum adenosine deaminase and its isoenzymes in patients with ovarian cancer

Ovarian cancer is the most lethal gynecological cancer worldwide. There are great relationships between the activities of adenosine deaminase (ADA), one of the enzymes in purine nucleotide pathway and carcinogenic process. In the present study the activities of the total ADA, ADA1 and ADA2 were measured in the sera of the patients with ovarian cancer. In this study, activities of tADA, ADA1 and ADA2 were assessed in sera of 30 patients with ovarian cancer and 30 normal control individuals, using a modified Ellis method in which only ADA2 activity was measured in the present of a specific inhibitor, erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA). Our results showed that the tADA, ADA1, and ADA2 serum activities of patients were found to be significantly increased (P < 0.05) than those of healthy control group. Although, ADA and its isoenzymes were not the specific markers for diagnosis of ovarian cancer, measurement of their activities may be used as a diagnostic means in ovarian cancer as well as the other analytical procedures

Effects of Dietary Nitrates on Systemic and Cerebrovascular Hemodynamics

Cerebral blood flow dysregulation is often associated with hypertension. We hypothesized that a beetroot juice (BRJ) treatment could decrease blood pressure and cerebrovascular resistance (CVR). We subjected 12 healthy females to control and BRJ treatments. Cerebrovascular resistance index (CVRI), systolic blood pressure (SBP), total vascular resistance (TVR), and the heart rate-systolic pressure product (RPP) measured at rest and at two exercise workloads were lower after the BRJ treatment. CVRI, SBP, and RPP were lower without a lower TVR at the highest exercise level. These findings suggest improved systemic and cerebral hemodynamics that could translate into a dietary treatment for hypertension