Jundishapur Journal of Health Sciences
Volume:13 Issue: 1, Jan 2021

Context: 

This study was done to review the electron contamination sources and measurement based on dosimetry and simulation techniques for radiotherapy and also to investigate factors affecting electron contamination reduction.

 We systematically searched five major indexing databases, including PubMed, Scopus, Embase, ISI web of science, and Cochrane central, using keywords of electron contamination, electron contamination AND measurement, electron contamination AND simulation, and electron contamination AND reduction until Dec 2020.

 Overall, 35 studies were reviewed, including articles reporting the theory of electron contamination, papers on dosimetry methods to measure electron contamination, studies about simulation methods to assess electron contamination, and articles about reducing electron contamination. The results indicated an increase in electron contamination using a flattering filter, an increase in field size, the presence of prosthesis in the patient's body, and a rise in photon energy.

 It can be concluded that the excessive delivered doses by electron contamination can cause skin complications, such as erythema, desquamation, and telangiectasia inside or outside the photon field. The amount of electron contamination depends on factors, such as radiation field size, beam energy, and materials placed in the photon path. Electron contamination can be decreased by increasing the source distance to the point of measurement by the dosimeter, applying a lead foil, magnetic deflector, or replacing a portion of air column between patient and radiotherapy system head by helium gas, and also limiting the treatment field.
 

 The aim of the present study was to assess clinical characteristics, management, and in-hospital outcomes of COVID-19 among oil refinery workers in a single referral center.

 This cross-sectional study was conducted in a non-COVID single referral center from March to August 2020. At the Naft Grand Hospital, a COVID-19 specimen collection and molecular detection unit was established, and staff were trained how to collect suitable samples (sufficiently deep swabs), store, pack, and transport them. The diagnosis of COVID-19 infection (SARS-CoV-2) was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR).

 Overall, 500 patients with confirmed COVID-19 infection were included, among whom the most common comorbidities were hypertension (52.2%) and diabetes (45.6%). Moreover, 298 patients (59.6%) had one to three comorbidities; 148 patients (29.6%) had four to six comorbidities, and two patients (0.4%) suffered from seven and more comorbidities. Out of these, 23 patients (4.6%) had cancer, and 206 (41.2%) suffered from other diseases. Most of the patients (390, 78.8%) received Kaletra, and 387 (78.02%) were treated with Azithromycin. Overall, PCR results were positive in 377 (75.4%) patients; computed tomography scan (CT-scan) was positive in 413 (82.6%), and CRP test rendered positive results in 335 patients (67%).

 Most referred cases were survivors with mild to moderate symptoms, and a few of them were unfortunately non-survivors. This could be due to the appropriate responses to treatment and institutional isolation of people with mild COVID-19 symptoms. Thus, good and evidence-based clinical care combined with intense public health interventions will save the lives of thousands, if not millions, worldwide.

During power plant operations, significant amounts of (PCBs)-contaminated soil are generated. PCBs enter the environment in various forms, causing toxicity in humans and other living organisms. Various technologies are used to remove PCBs from contaminated soils and sediments.

Bioremediation is an environmentally friendly method to improve areas infected with PCBs. In this study, to decontaminate PCB-contaminated soil, the effect of biological sludge in contaminated soil on the removal of PCBs was investigated in a vermicomposting process at different mix ratios.

Mixtures of PCB-contaminated soil and biological sludge were prepared in sample containers at different mix ratios, and then, earthworms were added. Over 80 days, besides the reduction of PCBs, pH, volatile solid content, and fixed solid content changes were also examined.

The highest reduction in PCBs (47.4%) was reported in pilot D at a contaminated soil-to-biological sludge volume ratio of 1:4. Moreover, in the same pilot, the pH level decreased from 7.9 to 7.2, indicating a further decline compared to other pilots, attributed to the further reduction of volatile solids. The highest reduction in volatile solids occurred in pilot D, decreasing from 74.8% at the beginning of the experiment to 42.9% at the end. The largest amount of mineralization also occurred in the same pilot.

In this study, it was found that Eisenia fetida worms, along with microorganisms in the biological sludge, could function properly at all volume ratios of contaminated soil to biological sludge and could purify contaminants in a vermicomposting process.

 Loading of petroleum products consists of several parts, of which the arm platform section is known to be the source of most accidents.

 Therefore, this study was done to evaluate the risk of arm loading platforms using the bow-tie analysis (BTA) technique to identify the causes and the probability of occurrence of hazardous events.

 In this study, we first identified the risks of the loading arm using the expert’s judgment. The risk of overflow is considered as the top event. Then, the basic events were identified by the fault tree analysis (FTA), and the possible consequences of the top event were predicted using the event tree. Next, using the computational equations, the probability of spillover and its consequences were calculated. The path of the risk event from the causal phase to the consequent phase was also illustrated by sketching the structure of the BTA.

 A total of 14 basic events and 8 intermediate events were involved in the occurrence of the top event, and 5 consequences were identified for the risk of spillover. The probability of the top event occurring was calculated to be 3.12 × 10-7.

 According to the results of this study, tank overflow is one of the most important hazards in the loading arm section.

Heavy metals are dangerous environmental pollutants that cause health hazards to humans, plants, and other living organisms by entering the food chain.

This research was carried out around Mohammadabad Qazvin landfill with the aim of measuring the concentration of lead and nickel metals in three plant species, including Artemisia sieberi, Salsola orientalis, and Halimocnemis pilifera, as well as the soil of the region.

In order to study three plots of 50 × 50 meters with distances of 500 meters from each other in the direction of the prevailing wind in the area, sampling of soil, roots, and aerial organs of plant species was performed. After preparing the samples, the concentrations of lead and nickel metals were measured using an atomic absorption spectrometer.

The results showed that the soil of the three plots did not differ significantly in terms of the concentrations of lead and nickel. Also, there was no significant difference between the aerial organs and roots of the studied species in terms of the concentration of these elements. This difference was statistically significant only in H. pilifera in terms of nickel concentration at the level of 5%.

Considering the factors of accumulation and transportation of lead and nickel metals in the studied plants, it can be suggested that H. pilifera and A. sieberi species are suitable for remediation of lead metal from contaminated soils, while none of these species are suitable for nickel phytoremediation.

The noise pollution is among the major challenges of installing the equipment and development of industries. Controlling produced noise in small power plants is a necessity for its development. The present study was conducted to predict the reduction of exhaust noise pollution in a 25 MW gas power plant using the synthesized aluminum foam in a gas power plant under the construction. The noise pollution was measured in a similar gas power plant to predict noise sources in the Tarasht gas power plant. One centimeter thick aluminum foam was synthesized with an average size of about 300 - 500 µm and a porosity of 90%. The impedance tube was used to determine the sound absorption coefficient of aluminum foam. Then, the sound pressure level was predicted by ANSYS software before and after applying aluminum foam in a simulated environment on the exhaust duct wall. Results showed that with the 10 cm of thick insulation layer includes punctuating stainless steel plates, refractory fabric, and closed-cell aluminum foam at high frequency, at least an 8 dB reduction in the noise pollution was obtained the exhaust duct wall compared to the duct wall without the aluminum foam. Aluminum foam can be used as a suitable sound insulator in the power plant industry. Furthermore, it has various advantages over other insulators, such as the resistance to moisture, heat, and vibration attenuation due to noise, proper high rigidity at a low weight, and most importantly, less environmental pollution.