Search

An assessment of workers at the mechanized mining face of coal mines was conducted in China. The survey on the current status of subject exposure to noise of coal miners was administered by occupational health investigation and detailed record of work days. The noise dosimeter measurements of 211 workers were obtained, including coal cutting, supporting, transportation, crushing, and auxiliary (such as air pressure, pump, and maintenance). A total of 56.4% of the LEX,8h exceeded 85 dB(A), and the average 8-hour equivalent sound level of the workers at the mechanized mining face of these coal mines was 91.2 dB(A). Within the noise frequency from 500 to 6000 Hz, there was a "V" shift in the displacement value of hearing threshold. At the noise frequency of 4000 Hz, the hearing loss N50 (dB) of workers reached the maximum. The longer the exposure time, the higher risk both in high-frequency hearing loss and noise-induced deafness. The risk of high-frequency hearing loss reached the high-risk level at 25 years of work, while the risk of noise deafness reached the high-risk level after 30 years of work. In addition, the Pearson correlation coefficient between the noise exposure time and the risk of noise-induced hearing loss was high and positively correlated. The results show that the production noise hazards at the mechanized mining face of coal mine are relatively large. High levels of hazardous noise exposure are typical in coal mines. The noise exposure data can help to develop more feasible noise controls for the employer. [ABSTRACT FROM AUTHOR]

Objective: To explore the balance of peripheral blood T helper 17 cells/regulatory T cell (Th17/Treg) ratio and the polarization ratio of M1 and M2 macrophages in lower extremity arteriosclerosis obliterans (ASO). Methods: A rat model of lower extremity ASO was established, and blood samples from patients with lower extremity ASO before and after surgery were obtained. ELISA was used to detect interleukin 6 (IL-6), IL-10, and IL-17. Real-time RCR and Western blot analyses were used to detect Foxp3, IL-6, IL-10, and IL-17 expression. Moreover, flow cytometry was applied to detect the Th17/Treg ratio and M1/M2 ratio. Results: Compared with the control group, the iliac artery wall of ASO rats showed significant hyperplasia, and the concentrations of cholesterol and triglyceride were significantly increased (P<0.01), indicating the successful establishment of ASO. Moreover, the levels of IL-6 and IL-17 in ASO rats were pronouncedly increased (P<0.05), while the IL-10 level was significantly decreased (P<0.05). In addition to increased IL-6 and IL-17 levels, the mRNA and protein levels of Foxp3 and IL-10 in ASO rats were significantly decreased compared with the control group. The Th17/Treg and M1/M2 ratios in the ASO group were markedly increased (P<0.05). These alternations were also observed in ASO patients. After endovascular surgery (such as percutaneous transluminal angioplasty and arterial stenting), all these changes were significantly improved (P<0.05). Conclusions: The Th17/Treg and M1/M2 ratios were significantly increased in ASO, and surgery can effectively improve the balance of Th17/Treg, and reduce the ratio of M1/M2, and the expression of inflammatory factors. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos de Neuro-Psiquiatria is the property of Thieme Medical Publishing Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The quantitative characterization of mineral composition and pore structures in tight sandstones is the core content of sweet spot prediction in unconventional oil and gas reservoirs. In this study, taking the Lower Permian tight sandstone reservoirs in the northern Ordos Basin, China as an example, the pore structures, and the complexity of the pore structures and minerals of the tight sandstone were systematically studied using constant-rate mercury intrusion and digital core technology based on 3D CT scanning experiments. The results show that the pore diameter of the tight sandstone is mainly distributed between 50 and 350 μm, and the capilary radius is mainly between 1.5 and 6.5 μm. Through filtering and denoising, 3D CT scanning technology can distinguish the internal pores and matrix components of tight sandstone reservoirs well. According to the statistical results, the development degree of pores in the rock is related to the coordination number of pores. The coordination numbers of reservoirs with more developed pores are mainly distributed between 2 and 4, with an average value of 3.6. The overall spatial distribution of the mineral structure of tight sandstone has good fractal characteristics. Minerals with larger sizes have more complex structures and have a greater impact on the accommodated space inside the rock. The study also found that there is a good correlation between the fractal dimension Dd of the tight sandstone based on CT scanning and the petrophysical parameters. As the Dd value increased from 1.15 to 1.55, the rock porosity decreased from 14% to 5.5%. Therefore, the larger the size of the mineral particles in the tight sandstone, the larger the storage space. [ABSTRACT FROM AUTHOR]

Stall in centrifugal pumps is a complicated flow phenomenon, which is detrimental to the pumps' safety and stable operation. Using a high-frequency particle image velocimetry (PIV) system (f=10k Hz) and a bench-scale refractive index matching experimental setup, two measurement methods are introduced to observe the dynamic stall inception and evolution. In the first method, the flow rate was continuously reduced at an interval of 0.005Qd, and the experiment was carried out under stable flow rate condition. It shows the flow adjacent to the blade suction side gradually evolved from the flow separation into a broken vortex. The stall vortex moved toward the impeller's inlet and continuously grew, and resulted in significant changes in the main flow direction at the channel inlet. The formation and development of the other vortex structures in channel were closely related to the stall vortex at the inlet. The second method is the dynamic flow rate measurement, and the results show that the stall is not caused by the increase in the relative inflow angle. It was obtained that the velocity value in the stall channel near the suction side rapidly decreased; however in the nonstall channel, the velocity value increased at the channel inlet. By analyzing the velocity distribution in both flow channels before and after the stall, the mechanism of alternating stall is well explained. Meanwhile, it was obtained that the stall was more likely to originate from the flow separation near the blade suction side for low specific speed impeller. [ABSTRACT FROM AUTHOR]

This paper introduces the InVEST model and the design of an evaluation method of the river non-point source pollution load. Through analyzing the current river pollution problems, the key points of load evaluation are determined, and the specific steps of pollution load evaluation are designed. The evaluation method of total river pollutant load is designed by InVEST model. The optimization of river pollution load evaluation method is performed by linear analysis, and the evaluation of river non-point source pollution load is completed. To validate effectiveness of the proposed method, the waters near Hainan Island are divided into five regions to estimate the total chlorine and total phosphorus non-point source pollution loads. The results showed that the total chlorine pollution load was 446200 tons/year and the total phosphorus pollution load was 57700 tons/year. The chlorine pollution of cultivated land was the most serious, and the phosphorus pollution of construction land and cultivated land was the largest. The mass concentration of total phosphorus in Haikou, Dongfang and Lingao areas is between 0.05 and 0.075 mg/L, and the risk of eutrophication is serious, which needs to be controlled. The relative error of runoff simulation in this paper is less than 0.5%, and the simulation effect is better. [ABSTRACT FROM AUTHOR]

Lung cancer is the malignant tumor with the highest incidence in China. Early detection and identification of symptomatic lung cancer patients and timely screen out asymptomatic patients from high-risk groups require multiple cooperation. At present, although combined imaging, serology, genomics, proteomics and other methods have been combined to screen for suspected lung cancer, there are still problems such as missed diagnosis and misdiagnosis. Meanwhile, the spread of the corona virus disease 2019 (COVID-19) epidemic has brought new challenges to early lung cancer screening. Under the normalization of epidemic prevention and control, the work of early lung cancer screening should be changed accordingly: improve the population's awareness of cancer prevention and control, strengthen the management of medical procedures, improve the efficiency of tumor detection, optimize detection technology, and utilize internet and big data platforms rationally. We should establish an ideal model, combining multiple screening methods, which is streamlined and efficient for early lung cancer screening under normal epidemic prevention and control. [ABSTRACT FROM AUTHOR]

Solid rocket motor stabilizes combustion by adding aluminum powder, and to increase the force of the thrust. The combustion product of the engine is accelerated by the nozzle to form a high temperature and pressure two phase plume. A strong infrared radiation signal is produced. This paper is aimed at a model solid engine. Euler Lagrange method is used to describe the interaction between gas and solid particles, the detailed chemical reaction mechanism is used to calculate the afterburning effect in the plume. The radiative parameters of gases by line by line integration and particles are solved by the Mie theory. The particle scattering approximation method and light of sight method are used to calculate the radiation transmission, and the flow and radiation characteristics of the two phase plume of the solid engine are calculated and analyzed. [ABSTRACT FROM AUTHOR]

CO 2 volume mixing ratio (VMR) is the key parameter for simulating the infrared radiation of atmospheric background. However, it cannot be treated as the constant in the near space. In this paper, CO 2 VMR in the mesosphere and lower thermosphere (MLT), which has the least investigations in the near space, have been investigated using the CO 2 VMR data set between 65 km and 110 km from 2002 to 2016 of the Sounding of the Atmosphere using Broadband Emission Radiometry. An empirical model of CO 2 VMR is suggested based on multiple linear regression fitting. The fitting results are compared with the original data series to validate the model. The fitting coefficients, CO 2 VMR trends, are analyzed to confirm the model and reveal the key features of CO 2 VMR in the MLT region. [ABSTRACT FROM AUTHOR]

Background and objective Occurrence at a younger age has been demonstrated to be associated with a distinct biology in non-small cell lung cancer. However, genomics and clinical characteristics among younger patients with lung adenocarcinoma remain to be determined. Here we studied the potentially targetable genetic alterations by next-generation sequencing (NGS) assay in young Chinese patients with lung adenocarcinoma. Methods Eighty-nine surgically resected lung adenocarcinoma tissue samples from patients aged less than 45 years were collected with informed consent from all patients. Targeted NGS assays were used to identify actionable genetic alterations in the cancer tissues. Additionally, the genomic and clinical pathologic characteristics of 95 patients with lung adenocarcinoma who received NGS testing over the same period were analyzed retrospectively. Results The frequencies of targetable genetic alterations in 184 patients with lung adenocarcinoma were analyzed by defined age categories, which unveiled a distinctive molecular profile in the younger group, aged less than 45 years. Notably, higher frequency of anaplastic lymphoma kinase (ALK) and human epidermal growth factor receptor 2 (HER2) genetic alterations were associated with young age. However, a reverse trend was observed for kirsten rat sarcoma viral oncogene (K^AS), serine/threonine kinase 11 (STK11) and epidermal growth factor receptor (EGFR) exon 20 mutations, which were more frequently identified in the older group, aged more than 45 years. Furthermore, concurrent EGFR/tumor protein p53 (TP53) mutations were much more prevalent in the younger patients (81.6% vs 44.9%), which might have a poor response to treatment with EGFR-tyrosine kinase inhibitor (EGFR-TKI). Conclusion NGS assay revealed a distinctive genetic profile in younger patients with adenocarcinoma. High frequency of concurrent EGFR/TP53 mutations was found in the younger patients, which especially warranted personalized treatment in this population. [ABSTRACT FROM AUTHOR]