The National Disease Control and Prevention Bureau and the National Health Commission jointly issued an announcement on Notice on Carrying out Pilot Work of Occupational Health Classification Supervision and Law Enforcement, which presented a method of comprehensive risk assessment method of occupational disease hazards of employers. This method embraces relevant factors at full scale and is simple in operation, but its applicability and accuracy of assessment results need further practical study. Based on the steps of occupational health risk assessment and proven occupational health risk assessment methods available at home and abroad, this paper proposed improvements and discussed the comprehensive risk assessment method of occupational disease hazards of employers, so as to provide a technical basis to implement the occupational disease hazard classification management of employers for relevant government supervision departments.

Objective: To quantitatively compare five occupational health risk assessment models in assessing silica dust hazard risk in small open pits, so as to provide the reference for the research of occupational health risk assessment methodology Methods : Seven small open pits were selected as the evaluation sites. The models from Singapore, the United Kingdom's Control of Substances Hazardous to Health Essentials ( COSHH Essentials ), Australia, Romania, and the International Council on Mining and Metals ( ICMM ) were applied to assessing the occupational health risk of the workers exposed to silica dust. The risk ratios ( RRs ) were calculated, and the parallelism, accuracy and correlation of the evaluation results of the five models were compared. Results : The RRs of the Singaporean model, COSHH model, Romanian model, Australian model and ICMM model were 0.8, 1.0, 0.4, 0.6 and 0.8, respectively. The Singaporean model and the Australian model were able to distinguish transport drivers from sprinkler drivers in the health risk exposed to silica dust, which was consistent with the actual risk of the two posts. Except for COSHH model, the RRs of the other four models were positively correlated ( P<0.05 ); the RRs were all positively correlated with concentration ratios ( CRs ) ( P<0.05 ), and the correlation coefficient between RRs and CRs of the Singaporean model was the largest (0.801). Conclusion Among the five models, the Singaporean model can more accurately evaluate the hazard risk of silica dust in posts of open pits, and has a good correlation with the other models.

Objective:To investigate the changes of plasma prothrombin fragment 1+ 2 (F 1+2), tissue factor positive microparticle (TF+ MP) and thrombin antithrombin complex (TAT) level before and after the treatment of low molecular weight heparin combined with reteplase in patients with malignant tumor and lower extremity venous thrombosis. Methods:From July 2016 to October 2019, 64 patients with malignant tumors and lower extremity venous thrombosis in the Third Hospital of Changsha were selected, they were divided into observation group ( n=32) and control group ( n=32) by simple randomization. The control group was treated with low molecular heparin, and the observation group was treated with low molecular heparin combined with reteplase. The efficacy, clinical symptom improvement time, incidence of adverse reactions, difference in lower limb circumference, blood flow velocity, activated partial thromboplastin time (APTT), prothrombin time (PT), plasma F 1+2, TF+ MP, TAT level before and after treatment were compared between the two groups; the correlations of plasma F 1+2, TF+ MP, and TAT level with clinical symptom improvement time, peripheral diameter difference of lower extremity, blood flow velocity, APTT, and PT were analyzed. Results:The total effective rate of the observation group (87.50%) was higher than that of the control group (65.63%) ( P<0.05); The improvement time of clinical symptoms in the observation group was shorter than that in the control group ( P<0.05); After treatment, the peripheral limb diameter difference of the observation group was lower than that of the control group, and the blood flow velocity was higher than that of the control group ( P<0.05); The APTT and PT in the observation group were higher than those in the control group after treatment ( P<0.05); The plasma F 1+2, TF+ MP, and TAT level in the observation group were lower than those in the control group after treatment ( P<0.05); The levels of plasma F 1+2, TF+ MP, and TAT were positively correlated with symptom improvement time and lower limb circumference difference, and negatively correlated with blood flow velocity, APTT, and PT ( P<0.05); There was no significant difference in the incidence of adverse reactions (18.75%) between the observation group and the control group (12.50%) during the treatment period ( P>0.05). Conclusions:Plasma F 1+2, TF+ MP, and TAT expression in patients with malignant tumors and venous thrombosis of the lower extremity can be used as biological indicators to evaluate the patient's condition and treatment effect. Low molecular weight heparin combined with reteplase can significantly reduce the plasma F 1+2, TF+ MP and TAT level, promote the improvement of symptoms, effectively reduce the peripheral diameter difference of lower extremity, improve blood flow velocity and coagulation function, and has a significant effect.

Objective:A method to determine acrylic acid in workplace air was developed by silanization-gas chromatography.Methods:In March 2020, chloroacetic acid in air were absorbed by silica gel tube, the samples were dried, then were desorbed and silanized by acetonitrile: N, O-bis (trimethylsilane) trifluoroacetamide (2∶1, V/V) at room temperature, allowed quantitative analysis of chloroacetic acid as its silanization product by gas chromatography.Results:Calibration curve of the method was linear within the range 0-162.8 μg/ml and showed good linearity with linear equation: y=0.011 8 x, r=0.999 7. The determination limit of the method was 0.8 μg/ml, and the minimum detection concentration was 0.05 mg/m 3 (collect 15 L air) . The relative standard deviation ( RSD) was 0.5%-1.3% ( n=5) . Recoveries were between 98.6%-101.2%. Conclusion:The results prove silanization-gas chromatography is an accurate, simple and high sensitive method for determining chloroacetic acid in workplace air.

Objective:A method to determine acrylic acid in workplace air was developed by silanization-gas chromatography.Methods:In March 2020, chloroacetic acid in air were absorbed by silica gel tube, the samples were dried, then were desorbed and silanized by acetonitrile: N, O-bis (trimethylsilane) trifluoroacetamide (2∶1, V/V) at room temperature, allowed quantitative analysis of chloroacetic acid as its silanization product by gas chromatography.Results:Calibration curve of the method was linear within the range 0-162.8 μg/ml and showed good linearity with linear equation: y=0.011 8 x, r=0.999 7. The determination limit of the method was 0.8 μg/ml, and the minimum detection concentration was 0.05 mg/m 3 (collect 15 L air) . The relative standard deviation ( RSD) was 0.5%-1.3% ( n=5) . Recoveries were between 98.6%-101.2%. Conclusion:The results prove silanization-gas chromatography is an accurate, simple and high sensitive method for determining chloroacetic acid in workplace air.

Objective To explore the possibility of the inner vertical outer spiral complex tubular urethra scaffold vascularization in repairing long segment of urethral defect.Methods From August 2014 to October 2015,27 clean male New Zealand white rabbits were divided into 3 groups,S1 group was transfected recombinant vascular endothelial growth factor(VEGF) gene lentiviral vector group.S2 group was vascular pedicle transfer tube group.C group was simple stent group.A 3.0 cm inner vertical outer spiral complex scaffold was constructed by using the small intestine acellular matrix (SIS) and polylactic acid copolymer (PLGA) modified by type Ⅰ collagen surface,and adipose-derived mesenchymal stem cells (ADSC) and smooth muscle cells after transformation from New Zealand white rabbits.In S1 group,the seed cells were transfected by recombinant vascular endothelial growth factor (VEGF) gene lentivirus,which express VEGF protein.The complex scaffold was used to repair 3.0 cm rabbit urethral defect In S2 group,the untransfected cells were seeded into the scaffold and embedded in the skin near the groin artery 3 weeks for repairing urethral defect with vascular pedicle transfer tube.In group C,the unseeded scaffold was used to repair the urethral defect alone.Postoperative observation and urethrography were followed 4,8 and 24 weeks after implantation.The HE staining,fluorescence tracing,immunohistochemical and scanning electron microscopy were evaluated at the same phase.Results In S1 group,there were one urinary fistula and one urethral stricture-related death,respectively.The urethra was smooth and patent,histological examination showed active hyperplasia of urethral capillary.In S2 group,there were one urinary fistula and two urethral stricture-related deaths,respectively.The urethral was rough,local thinning or dilated.Fat accumulation and mucosal contraction were found in the urethral submucosal,respctively.In C group,there were one urinary fistula,three hypospadias,and three urethral stricture-related deaths.The thickness of the urethra was uneven and stricture bending.The urethral mucosa was poorly repaired and the scar was narrow.HE and CD31 staining showed that S1 and S2 groups were active in the proliferation of urethral capillaries,and the angiogenesis was abundant.VEGF staining showed that the cytoplasm of endothelial cell layer,smooth muscle layer of vascular wall and the urothelial epithelial cell layer were fully expressed at 24 weeks,especially in epithelial cell layer.CKpan staining showed that the epithelium of S1 and S2 group developed to stratified epithelium,and the morphology of urethra was similar to normal urethra at 24 weeks.The urethral epithelial in C group of grew poor as single-level,irregular arrangement,24 weeks is still a lack of effective stratified epithelium.HE and oα-SMA staining showed that the smooth muscle and actin gradually increased in group S1 and S2,α-SMA staining in group C was scarce and increased at 24 weeks.PLGA was encapsulated by the surrounding tissue and the structure of electrospinning was clear after 4 weeks,absorbed and degraded after 8 weeks and absorbed after 24 weeks.Conclusions The inner vertical outer spiral comnplex tubular urethra scaffold maybe a reasonable method in repairing long segment urethral defects,and the methods of tubular urethra scaffold vascularization by transfected VEGF gene recombinant lentiviral vector and vascular flap deserve more research.

Objective To investigate the feasibility of measuring femoral neck torsion angle and anteversion angle by laser projection method .Methods The femoral neck torsion angle and anteversion were observed and described .An angle measuring device was designed and produced .With the device , the femoral torsion angle and anteversion angle were measured by laser projection method two times .Statistical analysis was performed on the measured value , and sides difference .Results The differences between femoral neck torsion angle and anteversion angle were observed .There was no significant difference ( P >0.05, power =100%) between the two measurements by laser projection method . Measurements of the femoral anteversion were 13.58 °±6.55 °on the left side , and 12.15 °±5.83 °on the right side . Measurements of the femoral neck torsion angle were 18.50 °±7.38 °on the left and 19.08 °±8.59 °on the right .There was no significant difference between left and right side ( P >0.05 ) .Conclusion The laser projection method is the effective method in measuring femoral neck torsion angle and anteversion angle , and has excellent repeatability .

Objective To establish the expression profiles of microRNA (miRNA) in SMMC-7721 and CCC-HEL-1 cell lines in order to provide new clues to study the mechanism of miRNA function in hepatocellular carcinoma (HCC) and its treatment. Methods SMMC-7721 and CCC-HEL-1 cell lines were cultured in vitro. Total RNAs were extracted by TRIzol, followed by RNA quantification and quality control. The RNAs were used to detect the expression of miRNA in these two cell lines by miRNA array. The miRNA of interest was then verified by real-time PCR. Results In total,238 differentially expressed miRNAs were found, including 154 overexpressed and 84 underexpressed miRNAs. 64 miRNAs were upregulated more than 4 times and26 miRNAs were upregulated more than 10 times. 22 miRNAs were downregulated more than 4 times 10 miRNAs weredownregulated more than 5times, and 1 miRNA was downregulated more than 10 times. Real-time PCR validation suggested that has-miR-205 and has-let-7f in liver cancer increased by 2. 7 and 2. 3 times, respectively.Conclusion There are differences in the expression of miRNA between the SMMC-7721 and CCC-HEL-1 cell lines and the profiles of miRNA expression were established for both cell lines. It was found that has-miR-205 and has-let-7f were upregulated in liver cancer.

Objective To study the effects of histone deacertylase inhibitor (TSA) on promoter methylation and expression of E-cadherin gene in a hepatocellular carcinoma cell line SMMC7721. Methods Hepatocellular carcinoma cell line SMMC-7721 was treated with TSA (300 nm/L), MTT method was used to investigate the growth inhibition ratio, TUNNL was conducted to measure the apoptosis ratio, methylation-specific PCR (MSP) was employed to detect changes in the CpG island methylation of E-cad promoter region, Western blot technique was used to detect the expression of E-cad gene and DNMT3b before and after TSA treatment, respectively. Results TSA decreases the SMMC-7721 cell viability and induces apoptosis, the growth inhibition ratio was 21.85% compared with control group. The apoptosis ratio of control group was (4.69±0.56)% ,the apoptosis ratio of TSA treatment group was (14.94±0.91)%. The apoptosis ratio of TSA treatment group was significantly higher than that of control group(P = 0.000). Before treated with TSA, the CpG island of E-cad promoter region was methylated, and the expression of E-cad was negative. TSA treatment induces demethylation of the CpG island in E-cad promoter region, causes the re-expression of E-cad. TSA reduces the expression of DNMT3b. Conclusions TSA decreases the SMMC-7721 cell viability and induces apoptosis, reverses the methylation status of E-cad promoter region, and resumes E-cad gene expression. TSA may induce demethylation through down-regulating the expression of DNMT3b.

Objective To assess clinical applications of using diffusion-weighted imaging(DWI) in encephalic infection diseases.Methods 10 patients with encephalic infection diseases were investigated from September 2004 to June 2007.All patients underwent routine MRI and single-shoot DWI in which the thickness and space of routine MRI agreed with DWI.The ADC values at infection focus and opposite normal region were measured.Results Among the 10 cases,seven of them showed decreased ADC value when DWI presented hyper-intensity;whereas the other three,whose chronic infection were long-term,had increased ADC value while DWI presented iso-/hypo-intensity.Conclusion MRI diffusion-weighted imaging plays an important role in the diagnosis of encephalic infection diseases.