ABSTRACT
Background: It has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. Over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. The purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-sized WO3 against low energy x-rays. Materials and Methods: The radiation shields were constructed using nano and micro WO3 particles incorporated into an EPVC polymer matrix. The attenuation coefficients of the designed shields were evaluated for low energy x-rays [diagnostic radiology energy range]. Results: The results indicate that nano-structured WO3/PVC shields have higher photon attenuation properties compared to those of the micro-sized samples. Conclusion: Our experiment clearly shows that the smaller size of nano-structured WO3 particles can guarantee a better radiation shielding property. However, it is too early to draw any conclusion on the possible mechanisms of enhanced attenuation of nano-sized WO3 particles
ABSTRACT
In Iran, architectures are often unaware of the risk of radon inhalation and how to reduce radon levels. Furthermore, radon considerations are not implemented in construction methods, construction materials and building utilization by regulatory authorities. In this study after reviewing the meteorological changes of Ramsar over the past 50 years [1955-2005], a novel design for constructing dwellings in radon prone areas is introduced. Out of building interventions such as planting wind-tunnel-making trees will be discussed in another paper. Ramsar soil samples with 4 levels of specific activities [extremely hot, severely hot, very hot, and hot] were placed in a model house. Radon level monitoring was performed by using a PRASSI portable radon gas survey meter. For extremely hot soil samples, the radon levels inside the model house when windows were closed for 24 hours were 1615 +/- 516 Bq/m3. When windows which were in the wind direction or opposite the wind direction were opened for 24 h, the radon level decreased to 89 +/- 286 and 139 +/- 314 Bq/m3, respectively. Interestingly, when crossed windows were opened for the same duration, Radon level was 144 +/- 92 Bq/m3. In cold seasons, when windows are usually closed, Chimney effect reduced the radon level to 323 +/- 641. For severely hot, very hot and hot soil samples, natural ventilation-based interventions effectively reduced the radon level. Results obtained in this study clearly show that natural ventilation-based simple cost-effective interventions can significantly reduce the radon concentration in radon prone areas of Ramsar
Subject(s)
Ventilation , Environmental Monitoring , Soil , MeteorologyABSTRACT
Metabolic syndrome is a physiologic syndrome, characterized by increasing coronary heart disease risk factors like hypertension, diabetes, dyslipidemias and obesity. The aim of this study was to determine some metabolic syndrome factors and percent age of body fat and its relationship with maximal oxygen consumption among patients with Coronary Artery Disease hospitalized in the Coronary Care Unit. This was descriptive correlative study that 90 coronary patients 40-80 years old participated by available sampling. We used Non-Exercise Test formulas for maximal oxygen consumption Predicting. Fasting blood sample used for TG, FBS, HDL-C. Percent body fat was estimated by measuring 4 skin fold thicknesses and blood pressure was measured. The means of the factors of Metabolic syndrome and percent body fat were higher among females, compared to males. Decrease in HDL and increased blood pressure were the most prevalent among risk factors. There was a significant negative relationship between maximal oxygen consumption and body fat, FBS, SBP. According to our findings, the prevalence of risk factors of metabolic syndrome and percentage of body fat were high. With increase of body fat, FBS and SBP, all results of unhealthy lifestyles, maximal oxygen consumption is decreased
Subject(s)
Humans , Male , Female , Metabolic Syndrome , Oxygen Consumption , Risk Factors , Adipose TissueABSTRACT
Background: sleep is one of the basic requirements of human and any disruption in the normal flow of sleep, in addition to causing psychological problems, can also reduce a person's performance
Objective: This study was aimed to determine the relationship between the sleep quality and body mass index in chemical warfare victims with bronchiolitis obliterans
Methods: This was a cross-sectional study conducted at the respiratory clinic of Baqiyatallah Hospital in winter of 2007. A total of 93 victims of chemical warfare with bronchiolitis obliterans referred to the respiratory clinic were selected by nonprobability and convenience sampling method. Body mass index, as a variable impact on quality of sleep, was evaluated for its relationship with sleep quality. Sleep quality was measured with Pittsburgh Sleep Quality Index [PSQI]. Data were analyzed by descriptive and analytic statistics including Spearman's rank correlation, chi-square test, and the independent-samples t-test
Findings: Over 95% of subjects had undesirable sleep quality and the rest [4.4%] with desirable sleep quality. The mean BMI was 26.68 +/- 3.88. Of total population, 65.6% were overweight or obese. There was no significant correlation between sleep quality and BMI [P>0.05]. A significant correlation between the psychological disorders and undesirable sleep quality was found [P<0.05]
Conclusion: According to the data obtained, future studies regarding the psychological disorders and treatment protocols to improve the quality of sleep in chemical warfare victims are recommended
ABSTRACT
Ischemic brain strokes consist two Third of all strokes and their complications bear a lot of cost and disability for the patient and society. In this study we seek for the effect of Erythropoietin on ischemic brain strokes' outcome according to NIHSS [National Institutes of Health Stroke Scale] changes. This study is a RCT. All patients with focal neurologic deficit with primary suspicion of brain stroke underwent neuroimaging evaluations. After confirmation of new ischemic brain stroke, the patients with inclusion criteria randomized into two groups of cases and controls. NIHSS was defined for each patient and all patients received a routine treatment protocol. Erythropoietin 16000 IU as a bolus intravenous dose was given to case patients as soon as neuroimaging study confirmed new ischemic stroke and continued as 8000 IU each 12hr up to total dose of 56000 IU during 3 days. Patients were re-evaluated at days 14 and 28 and NIHSS was assessed by another neurologist blinded to patient's group. Finally NIHSS changes of both groups were compared with each other. Evaluations revealed that in days 14 and 28 during follow up, Erythropoietin was effective in NIHSS [P-value: 0.0001]. This effect is of value in LOC Commands [P:0.024], facial palsy [P:0.003], motor arm [P:0.0001], motor leg [P:0.0001], sensory [P:0.009] and best language [P:0.023]. Administration of High dose erythropoietin in first 24 hours can be effective on the reduction of ischemic stroke complication. However, a larger scale clinical trial is warranted
Subject(s)
Humans , Brain Ischemia , Stroke/complicationsABSTRACT
Introduction: Bronchiolitis has the major effect on patient's daily living. This study applied in order to the assessment of the quality of life in chemical warfare victims with bronchilitis obliterans
Methods: In this descriptive cross-sectional study, were selected 93 chemical warfare victims with bronchiolitis obliterans referred to respiratory clinic of Baqyatallah hospital by convenience sampling method for research. Quality of life was measured with St George's Respiratory Questionnaire
Results: Mean of scores of symptoms, activity and impact domains and global scores was 85.56, 77.38, 68.5 and 74.25 ordinary. Quality of life was significantly correlated with percent of chemical injury and reverse correlation with FEV1. Persons with diploma and up education and employees have better quality of life
Conclusion: This findings show severs decrease of quality of life in these individuals. Lower quality of life related to decrease of FEV1 and affected to eye, skin and psychology disorders show global attention to promotion of the quality of life in chemical warfare victim with bronchiolitis obliterans
ABSTRACT
The dose rate distribution delivered by a low dose rate [137]Cs pellet source, a spherical source used within the source trains of the Selectron gynecological brachytherapy system, was investigated using the MCNP4C Monte Carlo code. The calculations were performed in both water and Plexiglas and the absolute dose rate distribution for a single pellet source and the AAPM TG-43 parameters were computed. A spherical phantom with dimensions large enough [60 cm] was used to provide full scattering conditions. In order to score dose at different distances from the source centre, this sphere was divided into a set of 600 concentric spherical shells of 0.05 cm thickness. The calculations were performed up to a distance of 10 cm from the source centre. To calculate the effect of the applicator and dummy pellets on dose rate constant and radial dose function, a single pellet source was simulated inside the vaginal applicator, and spherical tally cells with radius of 0.05 cm were used in the simulations. The F6 tally was used to score the absolute dose rate at a given point in the phantom. The dose rate constant for a single active pellet was found to be 1.102 +/- 0.007 cGyh[-1]U[-1], and the dose rate constant for an active pellet inside the applicator was 1.095 +/- 0.009 cGyh[-1]U[-1]. The tabulated data and 5th order polynomial fit coefficients for the radial dose function along with the dose rate constant are provided for both cases. The effect of applicator and dummy pellets on anisotropy function of the source was also investigated. The error resulting from ignoring the applicator was reduced using the data of a single pellet. The results indicate that F[r, theta] decreases towards the applicator
ABSTRACT
The introduction of magnetic resonance [MR] technology as a clinical imaging method has substantially increased the patient exposure to static, gradient and radio frequency of electromagnetic fields. The aim of this study was to assess the release of mercury from human dental amalgam restorations after exposure to electromagnetic fields produced by conventional MR imaging. The pre- and post-interventional study design was used for this investigation. The study participants were composed of individuals who were scheduled for brain MRI and those who had at least 4 teeth with amalgam restorations. These restorations had to be at least one week or older. Thirty individuals, who met the inclusion criteria, were referred to magnetic resonance imaging [MRI] department. A questionnaire was used for each patient to collect basic information on past exposures to electromagnetic fields, occupation and life style. Biological specimens [5cc stimulated saliva] were collected just before and after MRI procedures. The magnetic flux density was 0.23 T, and the patient's duration of exposure to magnetic field was 30 minutes. The collected saliva samples were analyzed by laboratory for mercury level by using cold-vapor atomic absorption technique. The SPSS software and paired t-test were used for statistical analysis of mercury levels. The mean concentrations of mercury in saliva before and after MRI were 0.86 +/- 0.3 mg /dl and 1.13 +/- 0.5 mg /dl respectively. Data analysis using paired t-test showed a statistically significant difference between the mean concentrations of saliva mercury before and after MRI procedures. This study showed significant relationship between increased mercury levels in saliva of patients exposed to magnetic resonance imaging