Effect of Workplace Noise on Hearing Ability in Tile and Ceramic Industry Workers in Iran: A 2-Year Follow-Up Study

Introduction. Noise as a common physical hazard may lead to noise-induced hearing loss, an irreversible but preventable disorder. Annual audiometric evaluations help detect changes in hearing status before clinically significant hearing loss develops. This study was designed to track hearing threshold changes during 2-year follow-up among tile and ceramic workers. Methods. This follow-up study was conducted on 555 workers (totally 1110 ears). Subjects were divided into four groups according to the level of noise exposure. Hearing threshold in conventional audiometric frequencies was measured and standard threshold shift was calculated for each ear. Results. Hearing threshold was increased during 2 years of follow-up. Increased hearing threshold was most frequently observed at 4000, 6000, and 3000 Hz. Standard threshold shift was observed in 13 (2.34%), 49 (8.83%), 22 (3.96%), and 63 (11.35%) subjects in the first and second years of follow-up in the right and left ears, respectively. Conclusions. This study has documented a high incidence of noise-induced hearing loss in tile and ceramic workers that would put stress on the importance of using hearing protection devices

Shift Work Effects and Pregnancy Outcome: A Historical Cohort Study

Objective: Employed mothers face considerable amount of hazards. Especially shift work can impact pregnant women by affecting some hormones. This study was conducted to assess the adverse effects of shift work on pregnancy outcomes. Materials and methods: This historical cohort study was conducted in 2017 in order to assess the effect of shift work on pregnancy outcomes. The subjects were consecutively selected from pregnant women, which referred to Al Zahra and Shahid Beheshti hospitals, Isfahan, Iran for their pregnancy care. The effect of shift work on pregnancy and labor complications (low birth weight, small for gestational age, pre-eclampsia and eclampsia, intra-uterine growth retardation, spontaneous abortion, preterm delivery, excessive bleeding during labor, and type of labor) was assessed. The effect was adjusted for occupation and number of children as well. Data were analyzed by SPSS (ver. 17) usingT-test, chi-Square test and logistic regression analysis. Results: Totally, 429 pregnant women entered the study. There was not a statistically significant difference between morning and shift workers regarding age. It was found that shift work probably increases the incidence of small for gestational age, pre-eclampsia and eclampsia, intra-uterine growth retardation, spontaneous abortion, and preterm delivery, but after adjustment for job and number of children the effect was observed only on preterm delivery. Conclusion: Working in a rapid cycling schedule of shift work may cause an increase in the incidence of preterm delivery in pregnant mothers

Efficacy of Low-Level Laser Therapy in the Management of Tinnitus due to Noise-Induced Hearing Loss: A Double-Blind Randomized Clinical Trial

Background. Several remedial modalities for the treatment of tinnitus have been proposed, but an effective standard treatment is still to be confirmed. In the present study, we aimed to evaluate the effect of low-level laser therapy on tinnitus accompanied by noise-induced hearing loss. Methods. This was a double-blind randomized clinical trial on subjects suffering from tinnitus accompanied by noise-induced hearing loss. The study intervention was 20 sessions of low-level laser therapy every other day, 20 minutes each session. Tinnitus was assessed by three methods (visual analog scale, tinnitus handicap inventory, and tinnitus loudness) at baseline, immediately and 3 months after the intervention. Results. All subjects were male workers with age range of 30–51 years. The mean tinnitus duration was 1.85±0.78 years. All three measurement methods have shown improved values after laser therapy compared with the placebo both immediately and 3 months after treatment. Laser therapy revealed a U-shaped efficacy throughout the course of follow-up. Nonresponse rate of the intervention was 57% and 70% in the two assessment time points, respectively. Conclusion. This study found low-level laser therapy to be effective in alleviating tinnitus in patients with noise-induced hearing loss, although this effect has faded after 3 months of follow-up. This trial is registered with the Australian New Zealand clinical trials registry with identifier ACTRN12612000455864)

Hearing Thresholds Changes after MRI 1.5T of Head and Neck

INTRODUCTION: Exposure to high intensity noise produced by MRI is a cause for concern. This study was conducted to determine the temporary and permanent effects of exposure to noise created by performing MRI on the hearing threshold of the subjects using conventional and extended high frequency audiometry. METHODS: This semiexperimental study was performed on 35 patients referred to Shahid Rahnemoun Hospital for head and neck MRI due to different clinical conditions. The hearing threshold of patients was measured before, immediately after, and 24 hours after performing 1.5 Tesla MRI using conventional and extended high frequency audiometry. SPSS version 18 was used to compare the mean hearing thresholds before and after MRI using paired T test and repeated measures analysis. RESULTS: Comparison of auditory thresholds in conventional and extended high frequencies before and immediately after MRI showed a significant shift at 4 KHz (P = 0.008 and P = 0.08 for right and left ears), 6 KHz (P = 0.03 and P = 0.01 for right and left ears), and 14 KHz (P =0.03 and P = 0.31 for right and left ears). However, there was no significant difference between audiometric thresholds before and 24 hours after MRI. CONCLUSION: Noise due to 1.5 Tesla MRI can only cause transient threshold shift

Increasing Accuracy of Speech Recognition Applications on Windows platform using .net framework

The intention behind developing speech recognition applications is to automate tasks. That is by accurately recognizing the user's input and taking action accordingly. There are many algorithms and techniques that one can apply in developing an ASR system, however the development resources play main factor in choosing these techniques. This paper focuses on .net framework as the main development resource and compares the possible approaches on designing ASR systems using this development resource. From this comparison the most effective and accurate one will be selected. Finally, we propose a method in designing an ASR system using .net framework that results in highest accuracy

Mechanics of Ice and Snow as a Granular Material

In this thesis, the mechanical properties of ice and dry snow as a class of granular materials are investigated through a series of experiments, analyses, and simulations. The primary focus is on understanding the intricate details of ice sintering, capillary bridge formation, and the behavior of snow under varying conditions. The investigation into ice sintering reveals a formulation of the sintering force, considering temperature, pressing force, contact duration, and particle size during the primary sintering stage. The results indicate a nearly linear increase in sintering force with external pressing force, while dependency on contact duration and particle size follows a nonlinear power-law relationship. The temperature dependence of the sintering force is nonlinear, aligning with the Arrhenius equation. The ultimate tensile strength of ice and the axial stress concentration factor are identified as crucial factors in determining the sintering force. Additionally, observations near the melting point reveal the formation of a liquid bridge between contacted ice particles. Moving on to capillary bridge formation, the experiments demonstrate the presence of a liquid bridge between an ice particle and a smooth (or rough) aluminum surface at controlled temperature conditions. The separation distance is found to be proportional to the cube root of the bridge volume, which decreases with decreasing temperature. Notably, for a rough surface, capillary bridge formation diminishes under the considered experimental conditions. The significance of snow in various contexts prompts an exploration of its mechanical properties. Utilizing micro-computed tomography imaging and quasi-static mechanical loading, a methodology for mapping the density-dependent material properties of manufactured snow is established. The study investigates structural parameter variations during loading, revealing insights into the three-dimensional structure, relative density, and mechanical behavior of snow. Results from Burger’s model show an increasing trend in modulus and viscosity terms with density. Digital volume correlation aids in calculating full-field strain distribution, highlighting particle characteristics and changes in specific surface areas during loading. Expanding the scope to natural snow, cutting-edge techniques like micro-tomography are integrated with traditional loading methods. Employing CT imaging and uniaxial compression tests, along with digital volume correlation, density-dependent material properties are analyzed. The study incorporates two snow samples, revealing density-dependent trends in modulus and viscosity terms. The results provide valuable insights into the non-homogeneous behavior of natural snow and contribute to fields such as glacier dynamics and avalanche prediction. Finally, the discrete element method with a variable bond model is used to simulate the behavior of granular materials, specifically focusing on snow. The model incorporates temperature dependent cohesion and effectively captures the angle of repose and stress-strain behavior of snow. In summary, this thesis presents an investigation into the mechanical properties of ice, capillary bridge formation, manufactured snow, natural snow, and granular materials, providing insights and contributing to the understanding of ice and snow in various environmental and engineering contexts

On the Failure Initiation in the Proximal Human Femur Under Simulated Sideways Fall

The limitations of areal bone mineral densitymeasurements for identifying at-risk individuals have led tothe development of alternative screening methods for hipfracture risk including the use of geometrical measurementsfrom the proximal femur and subject specific finite elementanalysis (FEA) for predicting femoral strength, based onquantitative CT data (qCT). However, these methods needmore development to gain widespread clinical applications.This study had three aims: To investigate whether proximalfemur geometrical parameters correlate with obtained femurpeak force during the impact testing; to examine whether ornot failure of the proximal femur initiates in the cancellous(trabecular) bone; and finally, to examine whether or notsurface fracture initiates in the places where holes perforatethe cortex of the proximal femur. We found that corticalthickness around the trochanteric-fossa is significantly correlatedto the peak force obtained from simulated sidewaysfalling (R2 = 0.69) more so than femoral neck corticalthickness (R2 = 0.15). Dynamic macro level FE simulationspredicted that fracture generally initiates in the cancellousbone compartments. Moreover, our micro level FEA resultsindicated that surface holes may be involved in primaryfailure events

Capillary Bridge in Contact with Ice Particles Can Be Related to the Thin Liquid Film on Ice

We experimentally demonstrate the presence of a capillary bridge in the contact between an ice particle and a smooth aluminum surface at a relative humidity of approximately 50% and temperatures below the melting point. We conduct the experiments in a freezer with a controlled temperature and consider the mechanical instability of the bridge upon separation of the ice particle from the aluminum surface at a constant speed. We observe that a liquid bridge forms, and this formation becomes more pronounced as the temperature approaches the melting point. We also show that the separation distance is proportional to the cube root of the volume of the bridge. We hypothesize that the volume of the liquid bridge can be used to provide a rough estimate of the thickness of the liquid layer on the ice particle since in the absence of other driving mechanisms, some of the liquid on the surface must have been pulled to the bridge area. We show that the estimated value lies within the range previously reported in the literature. With these assumptions, the estimated thickness of the liquid layer decreases from nearly 56 nm at T = −1.7°C to 0.2 nm at T = −12.7°C. The dependence can be approximated with a power law, proportional to (TM − T)−β, where β &lt; 2.6 and TM is the melting temperature. We further observe that for a rough surface, the capillary bridge formation in the considered experimental conditions vanishes.Validerad;2023;Nivå 2;2023-11-15 (sofila);Full text license: CC BY</p