This is a review of ten articles about the applications and results of otoacoustic emissions and contralateral suppression of otoacoustic emissions in different clinical populations like neuropathy, central auditory processing disorder and acoustic tumors. This article helps to understand the advantages of this simple test.

Background and Objectives: In this study, contribution of exhaust emission and CO distribution was estimated in enclosed residential complex parking.Materials and Methods: This was a descriptive- analytical study consisted of two stages. In the first stage, the emission contribution of vehicles was determined. In order to determine the contribution of exhaust gas emissions, through gas species, only four species CO, O2, CO2, and N2 were measured. Concentration of CO, O2, and CO2 was estimated using data obtained from the vehicle emissions monitoring system. The amount of N2 was estimated from sum ratio of all species, which equals to 1. Then, using computational methods, the amount of the emission contribution from vehicles. In the second phase, to measure the distribution of CO pollutant, gas sampling and collecting was performed using sampling bags made of inert materials with a volume of 10 l at six points. Sampling was conducted in accordance with the requirements of OSHA ID 210. The Obtained data were analyzed using SPSS Ver.16 software and Pearson statistical test (P>0.05 means there was no significant difference).Results: Maximum contribution was estimated for Pride with amount of 44.4 g/s and minimum contribution was estimated for Tiba with amount of 0.3 g/s. The minimum and maximum distribution value of CO concentration was achieved 3.6 and 69.48 ppm respectively. It was found that no significant relationship was observed between the values of exhaust emissions and CO distribution. However, the distribution of concentration was associated with locations and the number of openings, the number and type of vehicle, time of operation of the vehicle, the vehicle performance, and environmental factors.Conclusion: Measuring vehicles CO emission indicated that the concentration was beyond the permissible level recommended by the World Health Organization at some. Moreover, it was indicated that natural air conditioning is an effective alternative for improving the air quality in built environments and suitable quality in built environments is achievable through reasonable architectural design, without need to spend too much expense.

BACKGROUND: Sudden sensorineural hearing loss (SSNHL) is a perplexing condition for patients and there are many controversies about its etiology, audiologic characteristics, prognostic factors, and treatment. METHODS: In this prospective study, we performed some audiologic tests, including PTA, IA, ABR, and OAE (TEOAE) before beginning treatment of 53 patients with SSNHL. We assigned the patients randomly to two treatment groups: oral steroids + acyclovir vs. intravenous urographin. Twenty-eight patients underwent Magnetic Resonance Imaging (MRI) of the Brain. RESULTS: Of 53 patients (22 female and 31 male), 22 (41.5%) had negative or no signal to noise ratio and overall correlation in TEOAE. Twenty-six patients (49%) had positive overall correlations less than 50%, and 5 patients (4.4%) had overall correlations >50%. Fifteen patients (28. 3%) responded completely or well, 20 (37.7%) responded partially, and 18 (33.9%) had poor or no response to the treatment. The mean values for overall correlation in 3 subgroups of patients (no response, partial response, and complete response) were – 3. 5% (± 1/16%), +11% (± 1/99%), and +36.6% (± 3/07%), respectively (P = 0.01). Twenty out of 52 patients had no reproducible wave in ABR (38.5%), and waves I, III, and V were absent in 40 (77%), 31 (59.6%) and 21 (40%) patients, respectively. There were some limitations (false positive and false negative results) in ABR use in our cases, but it may be useful in detecting site of lesion in SSNHL. Overall, according to the results of OAE, ABR, and brain MRI of these patients, 3 were affected by acoustic neurinomas, at least 1 had auditory neuropathy, and the site of lesion was cochlear in 6, and cochlear + retrocochlear in 13 patients. CONCLUSIONS: ABR has limitations for use in SSNHL and seems not to obviate the need for brain MRI, but may help in determining the site of lesions such as ischemia or neuropathy. Overall correlation (and S/N ratio) in TEOAE is a valuable prognostic factor in SSNHL, hence we recommend performing TEOAE in every patient with SSNHL.      

Purpose Biogas residues, digestates, contain valuable nutrients and are therefore suitable as agricultural fertilizers. However, the application of fertilizers, including digestates, can enhance greenhouse gas (GHG) emissions. In this study different processes and post-treatments of digestates were analyzed with respect to triggered GHG emissions in soil. Methods In an incubation experiment, GHG emissions from two contrasting soils (chernozem and sandy soil) were compared after the application of digestate products sampled from the process chain of a food waste biogas plant: raw substrate, digestate (with and without bentonite addition), digestates after separation of liquid and solid phase and composted solid digestate. In addition, the solid digestate was sampled at another plant. Results The plant, where the solid digestate originated from, and the soil type influenced nitrous oxide (N2O) emissions significantly over the 38-day experiment. Composting lowered N2O emissions after soil application, whereas bentonite addition did not have a significant effect. High peaks of N2O emissions were observed during the first days after application of acidified, liquid fraction of digestate. N2O emissions were strongly correlated to initial ammonium (NH4+) content. Conclusion Fertilization with dewatered digestate (both fractions) increased N2O emission, especially when applied to soils high in nutrients and organic matter.

The vehicle emissions mainly depend on the amount of consumed fuel، type of fuel and traveled distance. One way to combat with greenhouse gases and air pollution associated with oil consumption is to use alternative energy sources. However، the lack of infrastructures such as refueling stations is one of the major barriers to the adoption of alternative-fuel vehicles. In this study، as an operational approach for transition period، we propose a model to extend the vehicle routing problem to green vehicles. This is a NP-Hard problem، and consequently it is very difficult to solve the real-world instances. Therefore، we propose a solving method based on benders decomposition that equipped with a set of valid inequalities. Implementation of proposed algorithm on randomly generated problems leads to acceptable results in a reasonable time.