282 research outputs found
Pb and Cd accumulation in Avicennia marina from Qeshm Island, Persian Gulf
The accumulation of heavy metals Pb and Cd in the mangrove, Avicennia marina, was studied on the southern coast of Iran, particularly on and near Qeshm Island in the Persian Gulf. The samples were collected from 7 stations which they were analyzed by flame Atomic absorption spectrophotometer after chemical digestion. Maximum Pb and Cd in leaves are (34.50, 3.52 ppm) and minimum of them are in stems (2.00, 0.05 ppm) and the accumulation of metals in leaves is more than stems. The different between monitored stations and accumulation of metals in tissues (P≥0.01) was not significant and there was no significant relationship between the leaves and stems of metals concentration (P≥0.05) but it was significant relationship between concentration of Pb and Cd in leaf tissue and stem tissue alone (P<0.05). After entering these metals to food chain, are accumulated in human body and this matter may cause some disease by receiving metals more than provisional tolerable weekly intake (PTWI) of lead and cadmium, in adults which in 0.025 and 0.007 mg/kg body weight with standards ENHIS
Application of Queuing Analytic Theory to Decrease Waiting Times in Emergency Department: Does it Make Sense?
Background: Patients who receive care in an emergency department (ED), are usually unattended while waiting in queues.
Objectives: This study was done to determine, whether the application of queuing theory analysis might shorten the waiting times of patients admitted to emergency wards.
Patients and Methods: This was an operational study to use queuing theory analysis in the ED. In the first phase, a field study was conducted to delineate the performance of the ED and enter the data obtained into simulator software. In the second phase, "ARENA" software was used for modeling, analysis, creating a simulation and improving the movement of patients in the ED. Validity of the model was confirmed through comparison of the results with the real data using the same instrument. The third phase of the study concerned modeling in order to assess the effect of various operational strategies, on the queue waiting time of patients who were receiving care in the ED.
Results: In the first phase, it was shown that 47.7% of the 3000 patient records were cases referred for trauma treatment, and the remaining 52.3% were referred for non-trauma services. A total of 56% of the cases were male and 44% female. Maximum input was 4.5 patients per hour and the minimum input was 0.5 per hour. The average length of stay for patients in the trauma section was three hours, while for the non-trauma section it was four hours. In the second phase, modeling was tested with common scenarios. In the third phase, the scenario with the addition of one or more senior emergency resident(s) on each shift resulted in a decreased length of stay from 4 to 3.75 hours. Moreover, the addition of one bed to the Intensive Care Unit (ICU) and/or Critical Care Unit (CCU) in the study hospital, reduced the occupancy rate of the nursing service from 76% to 67%. By adding another clerk to take electrocardiograms (ECG) in the ED, the average time from a request to performing the procedure is reduced from 26 to 18 minutes. Furthermore, the addition of 50% more staff to the laboratory and specialist consultations led to a 90 minute reduction in the length of stay. It was also shown that earlier consultations had no effect on the length of stay.
Conclusions: Application of queuing theory analysis can improve movement and reduce the waiting times of patients in bottlenecks within the ED throughput
Numerical analysis of thermal stresses around fasteners in composite metal foils
The process of composite metal foil manufacturing (CMFM) has reduced a number of limitations associated with commercial additive manufacturing (AM) methods. The existing metal AM machines are restricted by their build envelope and there is a growing market for the manufacture of large parts using AM. These parts are subsequently manufactured in fragments and are fastened together. This paper analyses the thermal stresses around cylindrical fasteners for three layered metal composite parts consisting of aluminium foil, brazing paste and copper foil layers. The investigation aims to examine the mechanical integrity of the metallurgically bonded aluminium/copper foils of 100 micron thickness manufactured in a disc shape. A cylindrical fastener set at an elevated temperature of 100 °C is fitted in the middle of the disc which results in a steady-state thermal distribution. Radial and shear stresses are computed using finite element method which shows that non-zero shear stresses developed by the copper layer inhibit the axial slippage of the fastener and thereby establishing the suitability of rivet joints for CMFM parts
Optimization of Partially Textured Parallel Thrust Bearings with Square-Shaped Micro-Dimples
Demographic characteristics and the first program of colorectal cancer (CRC) screening in north of Iran (2016)
Background: Colorectal cancer (CRC) is one of the most common types of gastrointestinal cancers. This study aimed to determine the demographic characteristics and their relationships with the results of the first screening program for CRC in people over 50 years old in northern Iran. Methods: This cross-sectional study was conducted in 2016 on 924 eligible people over 50 years old. Initial screening was done by IFOBT and then colonoscopy was performed if the results were positive. The demographic characteristics of individuals including age, sex, place of residence, marital status, body mass index (BMI) and education level were investigated with the results of the colonoscopy and the test results. Results: The mean age of participants was 59.38 years, and the participation of women (57.0) and rural residents (54.2) were higher in the screening program. According to the demographic variables, age was considered as a strong independent predictor variable, so that the prevalence of positive test results was more than 2 times higher in subjects older than 70 compared with subjects aged �60 (OR =2.05; 95 CI, 1.18-3.55, P=0.010). Also, the chance of positive test result in the age group �55 years old was 23, with an increase of 64 in the age group above 75 years (P<0.001). Among the positive test subjects, 118 cases underwent colonoscopy. Conclusions: The prevalence of IFOBT positivity was increased with age. Therefore, given the aging population of the country, it is recommended to emphasize on the screening of older people in the general population. ©Journal of Gastrointestinal Oncology
Demographic characteristics and the first program of colorectal cancer (CRC) screening in north of Iran (2016)
Background: Colorectal cancer (CRC) is one of the most common types of gastrointestinal cancers. This study aimed to determine the demographic characteristics and their relationships with the results of the first screening program for CRC in people over 50 years old in northern Iran. Methods: This cross-sectional study was conducted in 2016 on 924 eligible people over 50 years old. Initial screening was done by IFOBT and then colonoscopy was performed if the results were positive. The demographic characteristics of individuals including age, sex, place of residence, marital status, body mass index (BMI) and education level were investigated with the results of the colonoscopy and the test results. Results: The mean age of participants was 59.38 years, and the participation of women (57.0) and rural residents (54.2) were higher in the screening program. According to the demographic variables, age was considered as a strong independent predictor variable, so that the prevalence of positive test results was more than 2 times higher in subjects older than 70 compared with subjects aged �60 (OR =2.05; 95 CI, 1.18-3.55, P=0.010). Also, the chance of positive test result in the age group �55 years old was 23, with an increase of 64 in the age group above 75 years (P<0.001). Among the positive test subjects, 118 cases underwent colonoscopy. Conclusions: The prevalence of IFOBT positivity was increased with age. Therefore, given the aging population of the country, it is recommended to emphasize on the screening of older people in the general population. ©Journal of Gastrointestinal Oncology
Laboratory Evaluation of Color Change and Surface Roughness of White Spot Lesions Treated with Resin Infiltration and Fluoride Therapy
Background and Objective: Two non-invasive treatment methods for treating white spot lesions (WSLs) include resin infiltration and fluoride therapy. Contradictions have been raised regarding the color change and surface roughness of the lesions based on these methods. Therefore, this study was conducted to investigate the color change and surface roughness of white spot lesions after treatment with resin infiltration and fluoride therapy.
Methods: In this laboratory study, 40 buccal and lingual sections were prepared from 20 extracted healthy premolar teeth. 10 samples were considered as the control group, and in the other 30 samples, decayed lesions were created artificially. White spot lesions were randomly prepared in three groups without treatment, 0.05% sodium fluoride solution and resin infiltration (n=10). Then, the rate of color change and surface roughness of the samples after being placed in black tea and also after brushing were measured and compared using spectrophotometer and profilometer.
Findings: The surface roughness of samples in resin infiltration, intact enamel and fluoride groups were 163.46±64.67, 259.6±43.12 and 293.92±41.36 micrometers, respectively (p<0.001). Before placing in tea and after brushing, no significant difference was observed in the color of the samples, but after staining, the color change in WSL (9.14±5.85), fluoride (17.40±4.13) and resin infiltration (12.13±4.88) groups was significant (p=0.004); the fluoride group showed significantly more color change compared to the WSL group (p=0.003), but the difference between the other groups was not significant.
Conclusion: The results of this study show that if the resin infiltration method is used in the treatment of white spot lesions, less surface roughness and color change is observed compared to fluoride therapy
Customized clinical practice guidelines for management of adult cataract in Iran
Purpose: To customize clinical practice guidelines (CPGs) for cataract management in the Iranian population. Methods: First, four CPGs (American Academy of Ophthalmology 2006 and 2011, Royal College of Ophthalmologists 2010, and Canadian Ophthalmological Society 2008) were selected from a number of available CPGs in the literature for cataract management. All recommendations of these guidelines, together with their references, were studied. Each recommendation was summarized in 4 tables. The first table showed the recommendation itself in clinical question components format along with its level of evidence. The second table contained structured abstracts of supporting articles related to the clinical question with their levels of evidence. The third table included the customized recommendation of the internal group respecting its clinical advantage, cost, and complications. In the fourth table, the internal group their recommendations from 1 to 9 based on the customizing capability of the recommendation (applicability, acceptability, external validity). Finally, customized recommendations were sent one month prior to a consensus session to faculty members of all universities across the country asking for their comments on recommendations. Results: The agreed recommendations were accepted as conclusive while those with no agreement were discussed at the consensus session. Finally, all customized recommendations were codified as 80 recommendations along with their sources and levels of evidence for the Iranian population. Conclusion: Customization of CPGs for management of adult cataract for the Iranian population seems to be useful for standardization of referral, diagnosis and treatment of patients. © 2015 Journal of Ophthalmic and Vision Research | Published by Wolters Kluwer - Medknow
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