Journal of Advances in Medical and Biomedical Research
Year:2009 | Volume:17 | Issue:68|Papers Count:13

Background and Objective: Lead is one of the heavy metals which releases into water and soil resources through industrial wastes and poses serious harmful effects on human health. This study was conducted to determine the biosorption capacity of lead by active biomass of lead resistant fungi.Materials and methods: In this study the lead – resistant fungi were isolated from effluent of Zanjan Lead and Zinc factory and lead biosorption capacities of isolated fungi were studied by biosorption experiments. A collection of fungi colony was isolated in SDA media and then every colony was cultured in separate media. The fungi colonies were identified via morphological characteristics and Lacto phenol Caten Blue. The MIC of fungi was determined and their lead biosorption capacities were measured by culturing the fungi in SDB media that were polluted with 50-200 mg/L of lead.Results: The isolated fungi were one Spp. of Rhizopus, two Spp. of Penicillium and one Spp. of Aspergillus. The MIC of Rhizopus was 2500 and for others was 3000 mg/L. The maximum lead biosorption capacities were 51.5, 19.2, 25.6 and 12.5 (mg per g of dry weight of fungi biomass) for Rhizopus, two Spp. of Penicillium and Aspergillus respectively.Conclusion: The maximum lead biosorption capacity of Penicillium and one Spp. of Aspergillus was higher than 70%, thus biosorption of lead is an efficient method for treatment of lead polluted effluents.

Background and Objective: Arsenic (As) is a highly toxic metalloid found in ground and surface waters. Arsenic contamination in drinking water leads to harmful effects on human health. In this study, the efficacy of Reverse Osmosis (RO) membrane technology was evaluated for arsenic removal from drinking water.Materials and Methods: This experimental study was carried out on RO membrane spiral - wound module (model: 2521 TE, CSM Co. Korea) in pilot scale. After preparation of sodium arsenate solution in the laboratory, performance of RO membrane system in arsenic (As) removal was investigated. Experiments were conducted with five different pressures (100, 130, 160, 190, 210 Psi), pH (4, 5.5, 7, 8.5, 10), temperature (20, 25, 30, 35, 40oC) and an initial As concentration of 0.2 mg/L. The influence of different feed concentrations (0.2, 0.5, 1, 1.5, 2 mg/L) on As removal efficiency was also examined. In each step, flux was measured and after 30 minutes samples were taken. Arsenic amount in feed and permeate were measured by silver diethyldithiocarbamate (AgDDTC) method.Results: The results of this study demonstrated that greater than 90% of As can be eliminated from drinking water. Also the results showed that the pressure of 190 psi, As concentration of 0.2-0.5mg/L, temperature of 25-30oC and pH=6-8 were the optimal conditions.Conclusion: Arsenic removal efficiency in optimal conditions of system performance was up to 99%.

Background and Objective: Exposure to propylene glycol can lead to many health risks on blood, skin and kidney. Biodegradation of synthetic wastewater containing propylene glycol was studied in a continuous conventional activated sludge bench scale reactor. Optimum conditions of microorganisms' growth for biodegradation of propylene glycol were determined by Taguchi method.Materials and Methods: Primary microorganisms for start up of the bioreactor were obtained from sludge return line of a municipal wastewater treatment plant and adapted to different concentrations of propylene glycol in a conventional activated sludge reactor. Optimum growth conditions of microorganisms and also operational conditions of the system including pH, influent COD, source of nitrogen and salinity were determined in three levels by Taguchi method.Results: COD removal efficiency in conventional activated sludge reactor for influent concentrations of 400, 700, 900, 1100 and 1300 mg/L were 98%, 95%, 95%, 90% and 85% respectively. Optimization of the process by Taguchi method showed that source of nitrogen urea, pH=8, salinity of 8% and influent COD of 1300 mg/L with importance priority of 41%, 25%, 17.11% and 16.142% were as optimum growth conditions of microorganisms and also operational conditions of the system for propylene glycol biodegradation respectively.Conclusion: According to the results obtained from this work, it can be concluded that optimum conditions of biological processes and improvement the efficiency of bioreactors can simply be done by the use of such experimental designs.

Background and Objective: Polychlorinated biphenyls (PCBs) are toxic, persistent, bio - accumulate and pose a risk of causing adverse effects on human health and to the environment. PCB compounds exert varios impacts on human depending upon age, route of entry, intensity and frequency of exposure. This study was conducted to determine the effect of UV-C, hydrogen peroxide and solvent on the photodegradation of PCBs.Materials and Methods: The photochemical reactor was of annular geometry (500 ml volume) with a cylindrical low-pressure mercury lamp emitting at 254 nm. The power emitted by the lamp was 6 W. The whole lamp was immersed into a reactor with temperature of 32±2 C. The PCBs were analyzed by GC/ECD equipment.Results: The degradation of total PCBs in terms of one, two and three lamps was 77.5%, 82.9% and 85.2% respectively. The degradation of total PCBs in terms of not using of H2O2  and using 10% and 20% of H2O2 were 74.5%, 79% and 94.5% respectively.Conclusion: The results of this experiments showed that UVC - photolysis of H2O2 leads to a degradation efficiency of PCBs only in the presence of ethanol.

Background and Objective: Working in sitting posture, specially using a poorly designed chair is one of the critical risk factors in developing low back pain. Low back pain is one of the most common musculoskeletal disorders (MSDs) and has been reported to occur in 50-90% of all adults with recurrent rate of up to 90%. The objective of this study was to design and develop ergonomic chair for Iranian office workers.Materials and Methods: In this study, chair-related anthropometric dimensions of 303 Iranian office workers were measured in both genders. ANSI-HFES 100/1988 standard protocol was used for chair design. Finally, using a usability test, the designed ergonomic chair was assessed by 60 men and women office workers.Results: Using anthropometrics measurements and ergonomic criteria for chair design and also considering technical limitations, an ergonomic chair was made. Then this ergonomic chair was compared with old made chair designs. Office workers' assessments between old chair design and new one showed a significant difference.Conclusion: In this study, design and development of construction of an ergonomic chair was successfully made which could be applicable to Iranian office workers in order to provide their comfort and well being.

Background and Objectives: Contamination of storage wheat to zearalenone producer molds represents a significant hazard to consumer health and has thus received increasing attention from food safety authorities and legislators. Various species of Fusarium genus are producer of different mycotoxins including zearalenone at certain conditions. These mycotoxins can enter into the human food and animal feed chain and cause premature or early thelarche, gynecomastia, primary and secondary mycotoxicosis in humans and animals.Materials and Methods: In this survey, contamination of 162 randomly collected wheat samples to zearalenone producer Fusarium was investigated using direct microscopic examination and culturing samples in specific media.Results: From studied 162 collected wheat samples, 160 (99%) samples had fungal contamination. Aspergillus niger, Penicillium Sp, other species of Asergillus (A. fumigatus, A. flavous, A. niveus, A. cchraceus,…) Fusarium Sp, Alternaria Sp, Cladesporium Sp, Gliocladium Sp. and Trichotecium Sp. were the most frequently detected microorganisms respectively.Conclusion: The presence of moulds such as Aspergillus Sp, Penicillium Sp, Fusarium Sp, Alternaria Sp, Cladesporium Sp, Gliocladium Sp, and Trichotecium Sp. in consumer wheat samples can lead to the presence of harmful mycotoxins and then could result in serious toxicity and illness in humans. As the fungal contamination has a strong influence on the ultimate quality of wheat, wheat end products and food safety, more attention to the quality and safety of wheat and wheat stored places are necessary.

Background and Objective: There are many chemical, physical and biological hazards which are threatening the dentists' health. In this study we assessed the effect of noise on Zanjan dentists hearing loss as one of the dentistry physical hazards.Materials and Methods: This cross sectional study was performed on all zanjan dentists in 2006-7. All dentists were examined by audiometer (CA76 and AC40). The exclusion criteria were hearing accidents and diseases. The data were statistically analyzed by T test (a=0.05).Results: Noise induced hearing loss was observed in most cases. Left ear was more susceptible than right ear. The men had more hearing loss than the women. (P value on Freq 8000HZ=0.001). Deutists with seniority of 10 years and over had more hearing loss than who have seniority of less than 10 years (P value on Freq 8000HZ= 0.004). The dentists in the age of 40 years old and over had more hearing loss than the ages below 40 year (P value on freq 8000HZ in the left ear=0.007, in the right ear=0.019). Left ear had more hearing loss than right ear. Noise induced hearing loss in extra–speech frequencies was more than speech frequencies. The noise frequency of dental equipments was between 70 to 105 db.Conclusion: Noise induced hearing loss which has threatened the dentists' health is an incurable problem that must be prevented. Regular audiometric exam, use of hearing protection devices and also the occupational health regulations must be implemented for dentists in order to reduce the risk of noise induced hearing loss.

Background and Objective: According to previous studies shift work could desynchronize the natural circadian rhythm of the body. Although some of the internal physiologic processes become active for adaptation of the body with this desynchronization. One of these physiologic processes is endocrine system and melatonin release. This hormone is one of the most important variants which represent the circadian rhythm in human. Since the pattern of secretion of this hormone in first ours of morning and during the day in Iranian workers in particular in shift workers is unknown, therefore we aimed to determine the 24 hours profile of melatonin in shift work and  permanent day shift nurses.Materials and Methods: This experimental study was carried out on forty four female nurses of the Shiraz university hospital, during 2006-2008. Thirty four people in study group had a cyclic shift work and 10 persons in control group had permanent day shift work. The serum samples with 3 hours intervals during 24 hours were taken from each person. The plasma concentration of melatonin was measured by ELISA. Our study was carried out under realistic conditions. The data were analyzed using one – way ANOVA.Results: The age range was between 22 to 50 years with a mean work history of 5.5 years. The highest and the lowest melatonin levels was found in shift work nurses at 04:00 pm (14.91 pg/mL), and 04:00 am (131.49 pg/mL). These values for permanent day work nurses in the same times was 1.02 pg/mL and 177.40 pg/mL respectively. There was a significant difference between circadian melatonin profile at different time points (P=0.000).Conclusion: The results of this study revealed that night work induces a consistent change in melatonin circadian profile with a progressive reduction at early morning (04:00 am) and awaking time (07:00 am). These changes will also disturb sleep cycle and level of consciousness during the night and activities during the day.

Background and Objective: Microbial food safety and food borne pathogens with antibiotic resistance or multidrug resistance is an increasing public health concern worldwide. Campylobacter is one of the most common causes of acute bacterial gastroenteritis in human, especially in children. The objects of our study were to determine the frequency and antibiotic resistance pattern of thermopilic Campylobacter spp. (jejuni and coli) in raw poultry and beef isolates.Materials and Methods: The samples of raw chicken and beef (packaged and non - packaged) were purchased from the different parts of Tehran and then transferred to laboratory. Specimens were enriched in Preston Broth and cultured on Campylobacter selective agar medium for 48h. After that, suspected colonies isolated and confirmed by standard tests. Antimicrobial sensitivity was carried out using disk diffusion method.Results: Out of 379 samples, Campylobacter spp was identified in 109(28.8%) cases comprising of C.jejuni (76.1%) and C.coli (23.9%). The rate of isolation from chicken (49.7%) was more than that of beef (7.9%). There was a significant correlation between the rate of contamination by Campylobacter and type of meat (P<0.05). 41.8% of packaged and 54.1% of non-packaged (P value=0.197) chicken samples and 4.5% of packaged and 9.8% of non -packaged beef samples (P value=0.105) were contaminated with Campylobacter. Among the variety of tested antibiotics, the highest resistance was found for Nalidixic acid (71%) and Ciprofloxacin (46.7%). None of the strains were observed to be resistant to Gentamicin.Conclusion: The high prevalence of Campylobacter jejuni contamination in chicken meat represents the absence of hygiene rules in slaughtering the poultries and transferring process. Isolated strains from meat show increasing susceptibility against Fluroquinolone. The reason of susceptibility increment in isolated Campylobacter strains could be misusage of consumption of antibiotics such as Enrofloxcin in chicken farms. Sensitivity to Gentamicin makes this drug a suitable alternative for treatment of Campylobacter infection.

Background and Objective: In recent decades studies have shown that the main cause of accidents is unsafe acts. Installation of safety signs is a complementary corrective action for unsafe act control. Therefore, the objective of the present study was to investgate the effects of safety signs on the modification of unsafe behaviours.Materials and Methods: This interventional study was carried out in one of the turbine manufacturing industries in Iran, based on safety behaviour sampling technique. The unsafe acts was first determined and recorded, then 71 standard safety signs was installed based on (ANSI -Z535.2 & 3-2007) and 3 and 6 months after that the behaviours were evaluated. The behaviours before and after using the safety signs were compared.Results: The frequency of unsafe behaviors was 41.7% before the intervention. The most frequent unsafe behaviours were not or incorrect use of personal protective equipments, taking improper postures and unsafe work at height. There and 6 months after the intervention, unsafe behaviours reduced to 27.3% and 31.3% respectively (p<0.005).Conclusion: The findings showed that safety signs have a statistically significant effect on the reduction of unsafe behaviours. However, this effectiveness will be reducing over the time.