This paper aims to establish a new method of calibration and positioning in quantitative analysis of multicomponents by single marker (QAMS), using Shuanghuanglian oral liquid as the research object. Establishing relative correction factors with reference chlorogenic acid to other 11 active components (neochlorogenic acid, cryptochlorogenic acid, cafferic acid, forsythoside A, scutellarin, isochlorogenic acid B, isochlorogenic acid A, isochlorogenic acid C, baicalin and phillyrin wogonoside) in Shuanghuanglian oral liquid by 3 correction methods (multipoint correction, slope correction and quantitative factor correction). At the same time chromatographic peak was positioned by linear regression method. Only one standard uas used to determine the content of 12 components in Shuanghuanglian oral liquid, in stead of needing too many reference substance in quality control. The results showed that within the linear ranges, no significant differences were found in the quantitative results of 12 active constituents in 3 batches of Shuanghuanglian oral liquid determined by 3 correction methods and external standard method (ESM) or standard curve method (SCM). And this method is simpler and quicker than literature methods. The results were accurate and reliable, and had good reproducibility. While the positioning chromatographic peaks by linear regression method was more accurate than relative retention time in literature. The slope and the quantitative factor correction controlling the quality of Chinese traditional medicine is feasible and accurate.

Objective To investigate the epidemiological and etiological characteristics of foodborne diseases in Shiyan City, and to provide targeted measures for the prevention and control of foodborne diseases. Methods The surveillance data of foodborne diseases reported by Taihe Hospital of Shiyan City from 2013 to 2018 was collected and analyzed. Results A total of 1 742 cases of foodborne diseases were analyzed. The incidence peaked twice during the year, May to August and October to November. The pre-school children (≤6 years old) were at the highest risk of contracting foodborne diseases, and were mainly those in kindergartens, as well as those not in school. Grain and grain products accounted for the highest proportion of the presumably exposed foods． The main location of eating contaminated foods was in households. A total of 1 217 samples were tested, and 92 were positive, of which 71 strains were detected with Salmonella, accounting for the highest proportion. Preschool children and the elderly (≥66 years old) had higher detection rates than others. The food of infants and young children was found to have the highest detection rate. Conclusion According to the epidemiology and etiological characteristics of foodborne diseases in Shiyan City, the publicity and education of food safety should be strengthened and the surveillance network system of foodborne diseases should be further improved.

Objective To realize the epidemiological and pathogenic characteristics of foodborne illness in Shiyan in 2019 and provide targeted measures for the prevention and control work of the foodborne illness． Methods The active surveillance data of foodborne illness in shiyan in 2019 were collected and analyzed. The Salmonella strains isolated from the patients with foodborne illness were tested with serotyping，PFGE molecular classification and drug sensitivity test respectively according to《National foodborne illness surveillance workbook 2019》. Result A total of 3 191 cases of foodborne illness were analyzed. The pre-school children were the highest-risk group of foodborne diseases. Grain and grain product was the main suspicious contaminated food．The main location of eating place was family. A total of 330 samples were tested. The positive detection rate of foodborne illness was 20.30%（73/330）.The main pathogen were Rotavirus and Salmonella,and the detection rates were 11.21%(37/330) and 4.85%(16/330) respectively. The pre-school children were the group with the highest detection rate, which was 57.27% (63/110). The dominant serotype of the 14 Salmonella strains isolated from patients were Salmonella typhimurium and Salmonella enteritis. 14 different genotypes were obtained through PFGE classification and clustering. 64.29% (9/14) of Salmonella strains were multidrug-resistant strains. The drug resistance rates of ampicillin and tetracycline were the highest, which were 71.43%（11/14）and 64.29%（10/14）respectively. Conclusions The publicity and education of food safety should be strengthened and the surveillance network system of food-borne disease should be further improved according to the epidemiological and pathogenic characteristics of foodborne illness in Shiyan in 2019, and the use of clinical antibiotics should be controlled reasonably as well.

Objective To compare the detection effects of Legionella pneumophila in water samples from public places by the Legiolert enzyme-substrate method and the conventional cultivation. Methods The Legiolert enzyme-substrate method and the conventional cultivation method were used to detect Legionella pneumophila in cooling water and shower water samples collected in public places. Isolated strains were verified and serotyped. Results A total of 68 samples were collected and tested. The positive rate of the conventional cultivation and the Legiolert enzyme-substrate method were 5.88%（4/68）and 35.29%（24/68）, respectively, with a significant difference （χ²=16.41，P<0.01）. The coincidence rate of the two methods was 64.71% (44/68), and the difference of the detection effects of the two methods was statistically significant (χ²=16.41，P=0.000). A total of 25 strains of Legionella pneumophila were isolated，and the serum types were mainly LP1（14/25）. Conclusion The Legiolert enzyme-substrate method represente a higher detection rate of Legionella pneumophila in water samples from public places than the conventional cultivation.

Objective To investigate the influence of individual factors and labor organization factors on work-related musculoskeletal disorders (WMSDs) in automobile manufacturing workers, and to provide a scientific basis for the prevention and treatment of WMSDs in automobile manufacturing workers. Methods In April 2020, 5564 workers in an automobile factory were selected by cluster sampling method. The prevalence of WMSDs was investigated by using the Musculoskeletal Disorders Questionnaire, and the influence of individual factors and labor organization factors on WMSDs was investigated by using generalized estimation equation. Results The prevalence rate of WMSDs was 79.00% (4396/5564), and the prevalence rate of multisite WMSDs was 67.95% (3781/5564). The analysis of generalized estimation equation showed that doing the same job every day (OR= 1.478, P < 0.05), age ≥40 years (OR=1.416, P< 0.05), personnel shortage (OR= 1.356, P < 0.05), and work length of 6～10 years and 11～15 years (OR= 1.349, P< 0.05) were the main risk factors for WMSDs in automobile manufacturing workers. Shift work and working time > 40 hours per week increased the risk of WMSDs (P< 0.05). Male and adequate rest time were protective factors for WMSDs. The job correlation matrix showed that WMSDs in most parts had a positive correlation. Conclusions The prevalence of multisite WMSDs of workers in automobile manufacturing industry is high, and unreasonable labor organization is the main risk factor of WMSDs. Appropriate work breaks can effectively reduce the risk of WMSDs, and effective intervention measures should be carried out to prevent the occurrence of WMSDs in workers in automobile manufacturing industry. The generalized estimation equation can better analyze the influencing factors of WMSDs.

Objective To evaluate the risk of hearing loss of assembly workers in an automobile manufacturing factory. Methods An 8-hour equivalent sound level monitoring was carried out for assembly posts in an automobile factory. The risk of noise-induced hearing loss of assembly workers was measured using the method specified in ISO 1999:2013(E). The risk of noise-induced hearing loss was assessed in a graded manner according to the Guidelines for the Management of Occupational Disease Hazards from Noise. The results were statistically analyzed using Pearson correlation analysis. Results The average 8-hour equivalent sound level of the assembly work post in this automobile manufacturing factory was 89.5 dB (A). At 4000 Hz, the hearing loss N₅₀ (dB) of assembly workers reached the maximum. The longer the exposure time, the higher the risk of high-frequency standard hearing threshold shift. The risk of high-frequency standard hearing threshold shift was at a relatively high level at 30 years of work, while the risk of noise deafness reached a higher level after 40 years of work. Conclusion The 8-hour equivalent sound level (L_EX,8h) of assembly workers in the automobile factory exceeds the occupational exposure limit. With the increase of exposure years, the risk of high-frequency standard hearing threshold shift and noise deafness increases.

As imaging technology develops rapidly, dynamic and static guided technology is widely used in many medical fields now. In order to improve the success rate, reduce surgical complications and improve future prognosis, domestic and foreign experts have introduced digital navigation technology into apical surgery. With the help of digital navigation technology, apical lesions can be easily located and the scope of osteotomy can be limited, which can make the surgery be completed accurately, especially in complex clinical cases. This study overviews the clinical use and research progress of dynamic and static guided technology in apical surgery, summarizes the advantages and disadvantages of this technique as well as looks forward to its future.
Technology ; Endodontics ; Diagnostic Imaging

Objective To monitor the indoor radon concentration of urban residents in Shiyan, China, and to analyze the related influencing factors. Methods From April to July, 2019, RSKS standard detectors were used to measure the indoor radon concentration of 125 households in Shiyan, and the results were analyzed. Results The indoor radon concentration of residents in Shiyan showed a skewed distribution, ranging from 13.8 to 145 Bq/m³, and M (P₂₅,P₇₅) was 38.3 (29.0,62.0) Bq/m³. The estimated annual effective dose of radon and radon daughters from inhalation was 0.52-5.50 mSv, and M (P₂₅,P₇₅) was 1.45 (1.10, 2.36) mSv, which was consistent with literature. Building structure (H = 14.10, P < 0.001), floor (H = 24.41, P < 0.001), and geographical region (H = 8.963, P < 0.05) were influencing factors of indoor radon concentration, and the differences were significant. Conclusion The indoor radon concentration of urban residents in Shiyan is lower than the national standard limit. However, in daily life, it is still necessary to take appropriate measures to reduce the concentration of indoor radon as much as possible.

Objective To study the characteristics of noise hazards in automobile sand casting industry and understand the impact of noise on the health of automobile foundry workers, and to provide scientific data support for the control of noise hazards. Methods An automobile sand casting enterprise was selected as the research object. The post noise intensity test results from 2010 to 2019, the noise spectrum test results of each post in 2019, and the prevalence of occupational noise deafness in the 10 years from 2010 to 2019 were analyzed and sorted out. Using chi-square test and t-test the noise hazard characteristics and noise intensity changes were statistically analyzed. Results 1. The noise LEX.8h exceeding standard rate of foundry enterprises in the 10 years from 2010 to 2019 was not statistically significant（χ²=6.76, P=0.66), and the mean value of noise LEX.8h fluctuated horizontally in the 10 years, which was basically stable between 80 - 90 dB (A). 2. The mean value of noise intensity of sand falling, sand preparation, cleaning and shot blasting in the first five years was significantly different compared to that in the last five years. There was no statistically significant difference in other posts. 3. Among all posts in the foundry sand casting industry, the noise spectrum of core-making and cleaning posts was mainly medium and high frequency, while the noise spectrum of other posts was mainly medium and low frequency. 4, Cases of occupational noise deafness were mainly concentrated in cleaning and polishing workers, melting chemical workers, inspectors and other types of workers. Conclusions The noise hazards in the automobile foundry sand casting industry are mainly concentrated on the posts of molding, and sand falling, and the noise intensity and the over standard rate remain high in the past 10 years. The noise of each post is mainly medium and low frequency, and the noise of a few individual posts is mainly medium and high frequency. In recent years, due to the automatic renewal of equipment, the noise intensity of some posts such as sand dropping, sand mixing, cleaning and shot blasting has decreased, but the overall noise exceeding standard rate has basically not changed, and the noise hazard is still serious. The noise hazard of foundry sand casting enterprises is difficult to be controlled, and the risk of hearing loss of foundry workers is still high.

OBJECTIVETo investigate the anatomical bases for electrical coupling of mesenchymal stem cells (MSCs)-derived myocardial cells with host cardiac myocytes.

METHODSMSCs isolated from adult inbred Wistar rats were cultured and expanded in vitro and labeled with gree fluorescence protein (GFP). The model of acute myocardial infarction (AMI) was established in rats of the same species by occlusion of the left anterior descending arteries (LAD). One week after operation, 1.0x10(7) MSCs were injected into the infarcted area and 4 week after transplantation, the cardiac function of the recipient rats was evaluated. The heart tissues were taken after hemodynamic measurement for histological examination and morphometric measurement using image analysis system, and the expression of connexin-43 in the MSCs was detected by immunofluorescent cytochemistry.

RESULTSFour weeks after transplantation, the transplanted MSCs in the infarcted area showed significantly higher expression rate of connexin-43, and the cell transplantation resulted in decreased infarct size and thickening of the left ventricle wall.

CONCLUSIONIn a rat AMI model, MSCs differentiate into myocardial cells which can be integrated into host myocardial cells through formation of gap junction, resulting in effective improvement of the cardiac function.

Animals ; Cell Differentiation ; physiology ; Cell Proliferation ; Connexin 43 ; analysis ; Gap Junctions ; physiology ; Green Fluorescent Proteins ; genetics ; metabolism ; Immunohistochemistry ; Male ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stromal Cells ; cytology ; metabolism ; physiology ; Microscopy, Fluorescence ; Myocardial Infarction ; pathology ; physiopathology ; surgery ; Random Allocation ; Rats ; Rats, Wistar