106 research outputs found

    Characteristics of fluid inclusions in the Cenozoic volcanic-hosted Kushk-e-Bahram Manto-type Cu deposit of central Iran

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    The Kushk-e-Bahram Manto-type Cu deposit is located in central Iran, within Eocene to Oligo–Miocene volcanic strata which occur in the central part of the Uremia-Dokhtar Magmatic Arc (UDMA). Propylitization, silicification, argillization and carbonatization are the main types of alteration to have affected the pyroclastic and volcanic rocks. There are high amounts of oxide minerals, including malachite, azurite, hematite, magnetite and goethite. Three types of primary FIs have been determined in the Kushk-e-Bahram deposit, namely; I: two-phase liquid-rich FIs (L+V), II: mono-phase liquid FIs, III: two-phase vapour-rich FIs which have been identified based on petrographical studies. Based on FI studies of co-existing quartz and calcite, homogenization temperatures (Th) must have been between 67 and 228°C, with an average of 158°C. Moreover, salinity is between 14.0–30.3 wt% NaCl, equivalent to a 19.6% average. Fluid density values vary from 0.8 to 1.1 gr/cm3. Based on FI data and related diagrams, the depth of their trapping was estimated to be <200 m and ore formation occurred at pressures of <50 bars. Consequently, mineralogy, host rock and FIs characteristics in the Kushk-e-Bahram deposit are similar to the Manto-type Cu deposits in Mesozoic-Cenozoic volcanic belts of Iran and South America

    Mechanical Properties and Permeability of Sand Casting Moulds with Eggshells Binder

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    This research aimed to analyse whether or not eggshell could be a potential addition to sand mould composition as a binding material together with bentonite. Different amounts of eggshell material, i.e. 4%, 7%, 10% and 3%, were added to each sample. This study was a type of pre-experimental design called the one-shot case study. Among all sand moulds under study, sample 3 10% ES in dry conditions had the highest tensile, compressive and shear strengths of 0.09 Kg/cm2, 3.11 Kg/cm2 and 1.13 Kg/cm2, respectively. The results of the permeability test with heat treatment at 110˚C for 60 minutes showed that sample 3 10% ES had a permeability value of 178.3 ml/min

    Comparison of the Effects of Two Whitening Toothpastes on Microhardness of the Enamel and a Microhybride Composite Resin: An in Vitro Study

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    Introduction: Whitening toothpastes which have been accepted in populations may affect properties of enamel and restorative materials. The aim of this study was to compare the microhardness of human enamel and Z250 microhybrid composite resin after brushing with two whitening toothpastes.Materials and Methods: In this experimental study of enamel specimens, forty five freshly extracted human incisors were prepared and divided into three groups of control enamel (ClE), Crest enamel (CtE) and Aquafresh enamel (AfE). For composite resin specimens, forty five cylindrical-shaped specimens of light-cured Z250 composite were prepared and divided into three groups of control composite (ClC), Crest composite (CtC) and Aquafresh composite (AfC). The control groups were brushed without toothpaste. Crest and Aquafresh group specimens were brushed with Crest and Aquafresh whitening toothpastes, respectively. Vickers microhardness test wasperformed for all groups. Data were analyzed by One-way ANOVA and Tukey tests.Results: Microhardness values of ClE, CtE, AfE, ClC, CtC and AfC groups were 332.99 ± 26.59, 313.99 ± 20.56, 323.57 ± 27.96, 137.1 ± 3.16, 122.95 ± 3.27 and 130.36 ± 4.8, respectively. One-way ANOVA showed no significant differences among three enamel groups but there was significant difference among composite groups(p<0.01).Conclusion: Crest and Aquafresh whitening toothpastes did not affect enamel hardness but reduced the microhardness value of Z-250 composite resin. However, Crest whitening toothpaste decreased the microhardness more than Aquafresh

    A Phenomenological Study of Identification Process in Male patients of a Referral Center with Abnormal Sexual Orientations (Homosexual) and Their Challenges

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    Introduction: The purpose of this research was to explain the identification process in young homosexual men. Material &amp; Methods: The method of this study was phenomenological. The data was categorized and processed based on Strauss and Glaser's interpretive analysis approach. In this research, participants were selected with a purposeful sampling method. Finally, a semi-structured interview was conducted with 15 referred homosexual men with a mean age of 23.9.  Result: results were classified into two aspects of the identification process, and challenges/risks. The process of identity formation in young homosexual men included three steps: a. childhood exploration, b. adolescent confusion and identity crisis, and c. youth encounter and acceptance. Also based on the challenges and risks, the experience of negative emotions, such as feeling frustrated, anxiety, guilt, and depression were achieved in the emotional dimension. Conclusion: Iranian homosexual men pass difficult periods to seek identity. And finally, they may not achieve a complete identity, their challenges include: 1) a. becoming sensitive and feeling differently from others, b. realizing his orientation, c. suffering a great deal of religious conscience and selflessness, d. starting to change orientation without success, e. accepting identity desperately. 2) a. realizing they cannot reveal gay identity in family and society, b. having to put on a mask and play a role, c. facing individual and social challenges and due to these tensions, d. facing emotional and behavioural challenges, e. referring to counsellors for getting help and finding his real and correct identity

    Clinical Dental Care Epidemiology, Prevalence, Symptoms and Routes of Transmission of Coronavirus Disease 19: A Systematic Review of Literature and Meta-Analysis

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    Objective: To evaluate the epidemiological evidence, symptoms, and transmission routes of Coronavirus Disease 19 for clinical dental care. Material and Methods: PubMed, Embase, ISI, Scopus, Medicine have been used to search for articles until October 2020. Therefore, EndNote X9 was used to manage electronic resources. A 95% confidence interval (CI) effect size, random effect model, and the REML method were evaluated. Forty-one articles were found. In the first step of selecting studies, 40 studies were selected to review the abstracts. Finally, six studies were selected. Results: The effect size of symptoms of COVID-19 was fever: 92% (ES = 0.92, 95% CI 0.79-1.06), cough: 73% (ES = 0.73, 95% CI 0.59-0.88), headache: 8% (ES = 0.8, 95% CI 0.06-0.22), myalgia 13% (ES = 0.13, 95% CI 0.01-0.27) and nasal congestion 22% (ES = 0.22, 95% CI 0.06-0.39). The following recommendations are appropriate during COVID-19 for dental emergency management: personal protective equipment and hand cleanliness practices, personal protective equipment (PPE), preprocedural mouth rinse, single-use (disposable), cone-beam computed tomography (CBCT) and periapical (PA) radiography, Rubber dam, sodium hypochlorite for root canal irrigation, disinfect inanimate surfaces, ultrasonic scaling instruments and airborne infection isolation. Conclusion: Fever should be used as the first sign in the diagnosis; dentists should measure the fever of all patients at the time of arrival and before any procedure and then ask about other symptoms

    Elimination of carbon monoxide using non-thermal plasma

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    Background and aims: Non-thermal plasma is considered as a successful new technology with high efficiency in the air pollution control. Various types of atmospheric pollutants adversely influence on the human health and the environment regionally and globally. Carbon monoxide has been introduced as a critical pollutant which can cause the environmental and health effects. The growing concerns about effects of air pollution on human health, and also more stringent strategies of choosing the air quality standards, have motivated the development of air pollution control techniques, particularly the non-thermal plasmas techniques. Therefore, the aim of this study is the removal of the carbon monoxide (CO) contaminants in the dry air and argon atmospheres in order to determine of the effective parameters. Methods: The current study has determined the effects of temperature, the CO concentration, the voltage and the residence time on the CO elimination efficiency by ASTM D 5835 method in the system of negative plasma reactor (diluted by dry air) and the system of positive plasma reactor (diluted by argon gas), simultaneously. Results: The results indicated that the temperature and the residence time did not have a significant effect on the CO removal in the both dry air and argon gas systems. However, the most important variable in the both systems was the voltage in the vicinity of 8 kilovolts with the p<0.05 and the mean effect of 37 and 13.2 in the dry air and argon gas systems, respectively. Conclusion: The results of CO elimination in the dry air and argon atmosphere indicate that the dry air system, due to present of the oxygen active ions, has better performance compared to the argon gas system

    Using an intersectionality approach to transform health services for overlooked healthcare users and workers after Covid-19

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    Globally, government responses to the covid-19 pandemic reinforced prevailing patterns of privilege and prejudice and further entrenched the inequitable distribution of health and disease in different populations.1-3 These patterns reflect how the legacies of historical discrimination combine with existing power structures to shape, condone, and continue social disadvantage and the unequal distribution of resources. Analysis of these inequalities within health systems from the perspective of intersectionality can help us understand their drivers and find solutions to reduce them. Tackling these inequalities can also help transform health services for improved pandemic preparedness.

    Using an intersectionality approach to transform health services for overlooked healthcare users and workers after covid-19

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    Intersectional analysis and action are needed to prepare for future pandemics and ensure more inclusive health services, say Mamothena Mothupi and colleagues

    Effect of milrinone on short-term outcome of patients with myocardial dysfunction undergoing coronary artery bypass graft: A randomized controlled trial

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    Background: Myocardial dysfunction needing inotropic support is a typical complication after on-pump cardiac surgery. In this study, we evaluate the effect of milrinone on patients with ventricular dysfunction undergoing coronary artery bypass graft (CABG). Methods: Seventy patients with impaired left ventricular function [left ventricular ejection fraction (LVEF) < 35%] undergoing on-pump CABG were enrolled. Patients were randomized to receive either an intraoperative bolus of milrinone (50 &#956;g/kg) or saline as placebo followed by a 24-hour infusion of each agent (0.5 &#956;g/kg/min). Hemodynamic parameters and transthoracic echocardiographic measurement of systolic and diastolic functions were the variables evaluated. Results: Serum levels of creatine phosphokinase (CPK), the MB isoenzyme of creatine kinase (CK-MB), occurrence of myocardial ischemia or infarction, and mean duration of using inotropic agents were significantly lower in the milrinone group (p < 0.05). There were no significant differences between the two groups regarding the development of ventricular arrhythmia, duration of cardiopulmonary bypass, intra-aortic balloon pump and inotropic support requirement, duration of mechanical ventilation, duration of intensive care unit stay and mortality rate. Although mean pre-operative LVEF was significantly lower in the milrinone group, there was no significant difference between post-operative LVEFs. Conclusions: We suggest that perioperative administration of milrinone in patients undergoing on-pump CABG, especially those with low LVEF, is beneficial. (Cardiol J 2010; 17, 1: 73-78
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