Objective: Thyroid hormone is necessary for normal development of the auditory system. The aim of this study was to investigate the rate of hearing impairment in congenitally hypothyroid (CH) patients, and its relation with factors such as CH severity and age at starting treatment, during CH screening program in Isfahan.Methods: Hearing acuity was assessed in two groups of children with (94 patients aged 4 months- 3 years) and without CH (450), between 2000-2006. OTOACOSTIC EMISSION (OAE) was performed by a two step method.After two tests without OAE signals bilaterally, they were referred for auditory brainstem response (ABR) test. Subjects with both OAE and ABR abnormal test results were considered to have hearing problem.Obtained data was compared in case and control group and also CH patients with and without hearing impairment.Findings: Three (3.2%) of patients and 1 of control group (0.2%) were diagnosed with sensorineural hearing loss. The rate of hearing loss was not different significantly in two studied groups (P>0.05). There was no difference between age of starting treatment and first T4 and TSH level in CH patients with and without hearing loss (P>0.05). CH neonates with hearing impairment had thyroid dyshormonogenesis according to the follow up results.Conclusion: The rate of hearing loss was low among our studied CH patients. It may be due to proper management of CH patients. In view of the fact that all CH neonates were dyshormonogentic and considering the relation between certain gene mutations and hearing impairment in CH patients, further studies with larger sample size, with regard to different etiologies of CH should be investigated to indicate the possible gene mutations related to hearing loss in CH.

Background: Excessive noise is known as the most physical harmful factor in the industrial societies. There are several hearing protection methods against noise. Compliance with noise is attributed as one of the protection mechanisms of auditory system.Objective: This aim of this study was to determine the effect of different exposures time to compliance noise on rabbit’s hearing protection by Distortion Product OTOAcoustic EMISSIONs (DPOAEs).Methods: This experimental study was carried out on 25 male three-months-old New Zealand white rabbits in five groups including group 1 as trauma group exposed to 105 dB SPL at 500-3000 Hz for 8 hours per day in ten days; groups 2, 3, and 4 as compliance noise groups with daily exposure to 80 dB SPL compliance noise at 500 to 3000 Hz for 1, 2 or 4 hours before exposure to 105 dB trauma noise in ten days and group 5 as control group. All rabbits were anesthetized for DPOAE measurement before any exposure and post-DPOAE measurement (16-20 hours following final exposure). Data were analyzed by ANOVA, TUKEY and DUNNET tests.Findings: Mean DPOAE response differences of right ear in groups 2, 3 and 4 (compliance groups) were much lower than group 1 (noise trauma group). No significant differences were observed between mean DPOAE response amplitudes at low and middle frequencies in right ear of groups 3 or 4 and control group. Differences between mean DPOAE response levels in trauma group compared to control group were statistically significant (P<0.05).Conclusion: Lack of significant differences between mean DPOAE responses of compliance and control groups suggests protective effect of compliance noise on hearing health before exposure to noise trauma.

Background and Objectives: The prevalence of hearing loss in infants with a risk factor is higher than ininfants without a risk factor. The aim of this work is determine the prevalence of hearing loss and identifythe most significant risk factors for hearing impairment in neonates hospitalized at neonates unit. Subjects and Methods: A total of 450 infants admitted to the neonatal unit of Abuzar hospital in Ahvazwere evaluated for hearing in October 2020 to April 2020. The hearing screening tests performedwere Transient Evoked OTOacoustic EMISSIONs (TEOAES) and the automated auditory brain stem response(AABR). Risk factors include birth weight less than 1500g, prematurity, family history of hearingloss, consanguineous marriage, hyperbilirubinemia, mechanical ventilation for more than 5 days, asphyxia, autOTOxic drugs, sepsis, hypoglycemia and Apgar less than 5 were in one minute after birth. Results: twenty neonates (4. 4%) had different type of hearing loss. MechanicalVentilation more than 5 days, sepsis, asphyxia, hyperbilirubinemia and Apgar<5 were considered riskfactors of hearing loss. Conclusion: The prevalence of hearing loss in neonate with risk factor is significant that raises the needfor hearing screening using TEOAE and AABR simultaneously. It is recommended that children withhearing loss risk factors be evaluated for hearing periodically.

Background and Objective: Hyperbilirubinemia is a common neonatal abnormality. Severe hyperbilirubinemia is a risk factor for auditory system injury. Auditory brainstem responses (ABR) are important in early diagnosis of hearing impairments in healthy term infants with elevated bilirubin levels requiring exchange transfusion.Materials and Methods: During a two- year- period (2007 - 2009), in a prospective descriptive analytical study, in Tehran Milad Hospital, 64 (32 female, 32 male), healthy term (> 37 weeks) infants, who required treatment or were treated with phOTOtherapy or received exchange transfusion for elevated bilirubin levels or jaundice, were studied. After obtaining a written consent from their parents, the infants were tested with auditory brain responses and results were analyzed using SPSS 16 software.Results: No significant correlation was found between ABR and age, weight, bilirubin level or ABO blood group. Nineteen out of 64 infants received exchange transfusion. Three out of 19 infants (16%) exhibited abnormal ABR and 16 infants (84%) had normal ABR. There was no significant correlation between exchange transfusions and ABR (P>0.05).Conclusion: The results pointed out that 14% of the infants with elevated bilirubin who required exchange transfusion had abnormal ABR. This indicates that elevated bilirubin levels even without inducing kernicterus should be considered as risk factors for hearing impairments. Further studies are needed on how long these tests may remain abnormal.

In recent decades, a number of efforts have been done at the national and international level to control and regulate the EMISSION of greenhouse gases. Compliance with limits imposed by regulations on emitting gases requires adaptation in existing facilities, making new investments and incurring other costs which are unbearable to many companies especially old ones. As the total reduction of EMISSIONs are intended for the sake of environment, certain mechanisms should be designed to allow pollutants to buy the credit of other companies instead of reducing their own EMISSIONs. The sale and purchase of credit obtained as a result of reduction in EMISSIONs is called "EMISSION trading". In this paper, we first provide a brief history and concept of EMISSIONs trading. Then, EMISSION trading at the international level will be discussed based on KyOTO PrOTOcol and regional EMISSION trading with reference to the European Union EMISSION trading program. Finally the legal framework of EMISSION trading and its basic elements will be discussed.

Positron EMISSION tomography (PET) is an intrinsically quantitative tool that provides a unique and unparalleled approach for clinicians and researchers to interrogate the heart noninvasively. The ability to label substances of physiological interest with positron-emitting radioisOTOpes has permitted insight into normal blood flow and metabolism and the alterations that occur with disease states. Positron EMISSION tomography (PET) of the heart has evolved as a unique, noninvasive approach for the assessment of myocardial perfusion, metabolism, and function. Because of the intrinsic quantitative nature of PET measurements as well as the diverse compounds that can be labeled with positron-emitting radioisOTOpes, studies with PET have provided rich insight into the physiology of the heart under diverse conditions.      

Bachgrounds and Objectives: Oil, gas and petrochemical are known as important sources of air pollutants and EMISSION of green house gases. About 99 percent of sulfur dioxide in the air is produced from human resources. Although several samples have been taken from industries and refineries’ output by environmental experts and private companies, but accurate assessment is not available based on pollutant EMISSIONs on product levels (EMISSION coefficients) and on the total amount of the annual EMISSION which, can be used as basic modeling of air pollution and planning.Materials and Methods: This study was cross sectional and the output of the chimney measured with Testo 350 XL system. Performance standard was determined based on ASTM D6522 EPACTMO30- 41. The amounts of sulfur dioxide were measured from Tehran oil refinery’s outlet from the beginning of the march 2007 till the year 2008 for 20 months. Sampling was carried out on averaged range (9 am to 14 pm)Results: The results showed that Northern Distillation unit produced pollutants’ concentration more than 3 times in the southern Distillation unit. An EMISSION of pollutants from Northern unit was, 2.8 times higher than the Southern unit. The northern EMISSION factor was 5.6 times higher than the value obtained from southern unit. The Concentration, EMISSIONs and coefficient of sulfur dioxide in North catalyst convert unit were more than 2 times in comparison with the same South unit. These three factors in northern concentration breakers unit were 3, 2.6 and 2.6 times higher than the Southern concentration breakers unit‚ respectively. Discussion: EMISSION rate in all northern units is 2 to 3 times more than similar southern units. The production volumes in northern units are higher than the southern units and the southern units designed properly to remove more pollutants .The use of new technologies in production processes and application of the latest scientific resources can play a major role on pollutants’ reduction.

The present study aims to estimate biogas potential of two Russian landfills situated in the republic of Tatarstan and in Moscow Region. Due to environmental, economic, social and energetic consideration of biogas for human being, utilization of such a by-product would be of high concern. To date, there are seven biogas utilization projects which have been developed and implemented at municipal solid waste landfills of Russia. The purpose of the research was to determine the biogas potential at the closed landfills. During the studies held in 2008; sampling, transportation, storage of biogas and landfill soil samples, laboratory investigations; physicochemical and analytical methods for measuring of proteins, carbohydrates and fats in the organic part of the soil and the analysis of empirical data by the methods of computer modeling and mathematical statistics were carried out. The obtained results of the research; concentrations of biogas components: methane, carbon dioxide, carbon oxide, nitrogen, hydrogen and oxygen, gas flows, composition of the organic part of the fields and analysis of gas distribution on the surface of the landfills; has shown scientific and practical importance. Results could be used for the assessment of biogas potential at the landfills for further biogas utilization projects implementation with electrical or thermal energy production.

Background: Global greenhouse gas EMISSIONs increasing are due to use of various energy sources. This causes adverse consequences for the environment including global warming, and has environmental effects on various areas, This paper aimed at assessment of greenhouse gasses EMISSIONs (CH4, CO2) result in one of the sugar production unit's practices in Sugarcane Development Company, south Iran, including sugarcane farms and sugarcane production plant.Methods: EMISSION factor method and process understanding has been used to estimate of CH4 and CO2 EMISSION from existing EMISSION sources and obtained data has been modified based on the opinions of experts and production staff.Results: Results showed lime kilns, diesel generators, steam boilers and electrical equipment were the main source of greenhouse gases, and the total EMISSIONs of carbon dioxide and methane were, 279695.528 and 3134.07 tons per year, respectively.Conclusion: Boilers of sugar plant and burning of sugarcane farms were the most contribution to CO2 and CH4 EMISSIONs, respectively. Moreover lime kiln and diesel generators showed the least carbon dioxide and methane EMISSION respectively.

Introduction: High power laser interaction with metal targets produces a high temperature plasma (hundreds ev to several kev) which is a good source of x-ray radiation.The produced x-ray is suitable for different applications including lithography, medical science, biology, (Inertial Confinement Fusion) ICF and space sciences. In practical uses, enhancement of x-ray yield or higher conversion of laser energy into x-ray yield is efficient.For such reasons, there is a great deal of interest in producing x-ray from plasmas and also in methods that could enhance the x-ray yield.Aim: Simulation of x-ray radiation from laser plasma and inspecting the effect of using laser prepulse on the x-ray yield.Materials and Methods: This investigation is made using atomic physics simulations.Firstly, plasma formation from high power laser interaction with metal target is simulated.Secondly, after the plasma parameters especially electron density and temperature are found, x-ray radiation is simulated using the corresponding equations of different mechanisms.Finally, the effect of laser prepulse is studied by correcting computer codes.Results: It was seen that deeper layers of the target are affected at greater times by the laser interaction and their temperature and density increase. For a laser pulse of 50 ps and 1015 W/cm2 the temperature and density across the target are about several hundred ev and 1023 cm-3, respectively. X-ray production is higher from the layers with higher electron density and especially electron temperature. In addition, the produced x-ray pulse duration (FWHM) approximately the same as the laser pulse i.e.50 ps. It was seen that by using prepulse, there is an optimum delay time (time separation between main pulse and prepulse) at which maximum x-ray yield is produced. The optimum delay time was about 400 ps and 1700 ps when the ratio of the prepulse to the main pulse intensities was 0.01 and 0.001, respectively.Also, calculations showed that decreasing the prepulse intensity increases the x-ray yield enhancement.Conclusion: The x-ray pulse duration emitted from laser plasma is about the same as the laser pulse. It was shown that using a prepulse with proper intensity and delay time can enhance the x-ray yield considerably. There is an optimum delay time at which maximum xray yield can be produced. The optimum delay time depends on the prepulse intensity.