Objective:To investigate epidemiological characteristics and influencing factors on dust-exposed working years of pneumoconiosis cases in Yantai.Methods:In January 2020, By Cluster sampling way, Using descriptive statistics to analyze dust-exposed working years of the reported 3307 new cases of pneumoconiosis from 2009 to 2019 in Yantai. Analyzing the variation trends by the chi-square trend test. Analyzing single fator by chi-square test. Using multiple classification Logistic Regression analysis to analyze multiple influencing factors.Results:The dust-exposed working age of pneumoconiosis cases decreased by years ( P<0.05) . The starting age of dust exposure of cases increased year by year, while positively correlated with the dust-exposed working age ( r=-0.217, P<0.05) . The years of dust exposure, starting age of dust exposure, industry, type of economy and scale of enterprise were main influence factors on the dust-exposed working age of pneumoconiosis cases. Conclusion:We should strengthen the management on prevention and control condition of pneumoconiosis in metal smelting and processing industry and privately-owned, small and micro enterprises, and pay attention to workers starting exposed to dust in the age of ≥28 years old.

Objective:To investigate epidemiological characteristics and influencing factors on dust-exposed working years of pneumoconiosis cases in Yantai.Methods:In January 2020, By Cluster sampling way, Using descriptive statistics to analyze dust-exposed working years of the reported 3307 new cases of pneumoconiosis from 2009 to 2019 in Yantai. Analyzing the variation trends by the chi-square trend test. Analyzing single fator by chi-square test. Using multiple classification Logistic Regression analysis to analyze multiple influencing factors.Results:The dust-exposed working age of pneumoconiosis cases decreased by years ( P<0.05) . The starting age of dust exposure of cases increased year by year, while positively correlated with the dust-exposed working age ( r=-0.217, P<0.05) . The years of dust exposure, starting age of dust exposure, industry, type of economy and scale of enterprise were main influence factors on the dust-exposed working age of pneumoconiosis cases. Conclusion:We should strengthen the management on prevention and control condition of pneumoconiosis in metal smelting and processing industry and privately-owned, small and micro enterprises, and pay attention to workers starting exposed to dust in the age of ≥28 years old.

Objective: To understand influencing factors on workers' personal protective equipment (PPE) usage, and provide a basis for standardizing the PPE use in the city. Methods: The basic information of workers exposed to occupational hazards in a municipal area was imported into SPSS 18.0 and numbered sequentially in May 2018. A simple random sampling method was used to select 1 678 workers as the research object, and then a questionnaire survey was conducted from June to July 2018. In the valid questionnaires collected, workers who self-rated as "full-time correct use of PPE" and were approved by occupational health managers of employing units were included in the "correct use group" and others in the "incorrect use group". χ² test was used to analyze the PPE use of different factors, and binary unconditional logistic regression analysis was used to analyze the influencing factors. Results: 1547 valid questionnaires were collected in this study, including 803 workers correctly used PPE at full time (51.9%) , and other workers never used or occasionally used PPE. There were statistical difference of PPE usage rate among workers of different sex, industry and wage type (P<0.05) . Occupational health supervisors setting example in PPE usage (β=0.368) , workmates using PPE correctly and reminding PPE usage (β=0.891) , posting warning specifications of occupational hazards (β=0.361) , setting up "safe man" at the entrance of workshop (β=0.585) , WeChat and other new media on occupational health knowledge propaganda (β=0.536) , punishing incorrect usage of PPE (β=0.252) 、sex (β=-0.512) and wage type (β=-0.203) are influencing factors affecting the usage of PPE. Conclusion PPE usage rate of the occupational population in the city is still fairly low, and the PPE usage is influenced by a variety of factors. Comprehensive measures should be taken by employers to ensure using PPE to protect workers' occupational health.

Objective To evaluate the CT features of radiation-induced jaw osteosarcoma(RIJOS) developed after therapeutic irradiation for a variety of nonosseous lesions.Methods The demographic and CT findings of thirteen patients with RIJOS were reviewed retrospectively.Observation items included location,bone destruction,mineralized tumor matrix,periosteal reaction,soft tissue extension and calcification.Of the thirteen patients,twelve were male and one was female.The mean age was 48 years (range:29-68 years).Five patients had tumors in the maxilla and eight in the mandible.All the patients underwent tumor resection.Results The latent period before development of RIJOS ranged from 3.5 to 14 years (mean,11 years).In all thirteen patients,eight tumors were osteoblastic,with one osteolytic and four mixed lesions.Osteoid tumor matrix mineralization was present in twelve patients.Periosteal reaction was identified in 11 cases.Soft-tissue extension was present in all patients beyond the area of bone destruction.Conclusions The characteristic CT imaging of RIJOS showed the bone destruction associated with a large number of mineralized tumor matrix and significant soft tissue extension in the original radiation field after radiotherapy.CT findings could play an important role in identifying the tumor and pre-operative assessment.

Objective To observe the nuclear translocation of transcription factor NF-κB and IRF-3 in TLR4 silenced EVC304 cells infected by HTNV and to provide new information for anti-HTNV innate immunity and its signal transduction. Methods TLR4~- cells and TLR4~+ cells were infected by HTNV 76-118, respectively. The cells stimulated by LPS were selected as positive control groups, and the cells without stimulation were selected as negative control groups. After 6 hours, indirect immunofluorescence assay(IFA) was used to detect the nuclear translocation of NF-κB and IRF-3. Results The transcription factor NF-κB and IRF-3 transfered into nuclear 6 hours after stimulated by HTNV 76-118. Conclusion TLR4 may mediate the nuclear translocation of transcription factor NF-κB and IRF-3 in HTNV infected human umbilical vein endothelial cells.

Objective To observe the morphological characteristics of HCV particles and intracel-lular ultrastructure changes in Huh7. 5 cells which was infected with chimeric HCV via transmission electron microscopy. Methods Plasmid J6/JFH encoding the full length HCV chimeric genome was transcribed to HCV RNA in vitro and the RNA was transfected into Huh7.5 cells by electroporation. Quantitative real-time PCR(qRT-PCR) was used to assay HCV copies of the supernatant of transfected cells. Indirect immunofluo-rescence was used to detect the expression of HCV proteins. The cell culture superoatant were used to infect narve Huh7.5 cells, transmission electron microscopy was used to observe morphological characteristics of vi-rus particles and intracellular ultrastructure changes in infected Huh7. 5 cells. Results qRT-PCR showed high level virus copies in supernatant of transfected cells collected in different times, indirect immuno-fluo-rescencc proved high expression of HCV NS5A proteins in the transfected cells. Large numbers of enveloped or unenveloped virus-like particles (VLPs) were observed in infected Huh7. 5 cells via transmission electronmicroscopy. We also found hyperplasia of some membrane-enclosed organelles in the cytoplasm. Several fea-tures characterizing flavivirus infected cells and a cytoplasmic inclusion of unknown origin were observed. Conclusion The chimeric HCV from in vitro cell culture system is proved to be intact virus particles which can efficiently infect Huh7.5 cells.

Objective To document MRI findings of soft tissue damages involwing the temporomandibular joint (TMJ) after dislocated condylar fracture. Methods Seventy-seven subjects (103 TMJs), who suffered from the dislocated condylar fractures, underwent both sagittal and coronal MR imaging including proton density-weighted image ( PDWI ) and TzWI.Results On MR images, the TMJ structural changes after dislocated condylar fractures included : ( 1 ) displacement of the dislocated fragment in the anterior-inferior direction ( 102 TMJs, 99.0% ) and in the anterior direction ( 1 TMJ, 1.0% ) ; (2)disc displacement (100 TMJs, 97.1% ) in the anterior-inferior direction (99 TMJs) and in the anterior direction (1 TMJ) along with the dislocated condylar fragments on sagittal MR images; (3) joint effusion (103 TMJs, 100%);(4) abnormal signal intensity in the retrodiskal tissues of the TMJ ( 91 TMJs ,88.3% ) ; (5) abnormal changes of inferior posterior attachments of disc ( 89 TMJs, 86.4% ) ; ( 6 )abnormal changes of joint capsule ( 89 TMJs, 86.4% ) ; ( 7 ) abnormal changes of superior posterior attachments of disc ( 37 TMJs, 35.9% ) ; ( 8 ) disc deformation ( 8 TMJs, 7.8% ) ; ( 9 ) disc avulsion (8 TMJs, 7.8% ) and ( 10 ) glenoid fossa fractures (4 TMJs, 3.9% ). Conclusion On sagittal MR images, the TMJ soft tissue changes after dislocated condylar fracture were mainly presented as the disc displacement in the same direction (anterior-inferior direction) as the dislocation of the fractured fragments,usually in association with joint effusion.

Objective To develop a reverse genetics system for Hantaan virus (HTNV) 84FLi strain by using RNA polymerase [ (pol Ⅰ)-mediated transcription. Methods Complementary DNA (cDNA) containing the coding sequence for chloramphenicol acetyhransferase (CAT) was inserted into the 5'-and 3'-terminal untranslated regions of HTNV 84FLi L segment. These chimeric cDNAs (pol Ⅰ expression cassette) were cloned into plasmids and between the human pol Ⅰ promoter and terminator to generate sense and anti-sense RNA pol Ⅰ transcription reporter plasmids. The reporter plasmids were transfeeted into 293T cells or the 1:1 combination of 293T and HTNV infected Vero cells. These cells were cotransfected with expression plasmids encoding Ⅰ. (RNA dependent RNA polymerase) and N (nucleoprotein) viral proteins, Cells were harvested 48 h post-transfection and the CAT activity was detected. The 293T cells were infected with the supernatant to explore the passage ability of CAT activity. ResultsThe reporter plasmids pLvRNA-CAT and pLcRNA-CAT were constructed successfully. CAT activity was detected in transfected cells and could also be serially passaged in the rescued virus minigenomes. Conclusion The RNA polymerase ]-driven reverse genetics system successfully rescues HTNV 84FLi minigenomes.

Objective To observe the protective effects of Toll-like receptor(TLR)-4 siRNA against acute liver injury in mice induced by lipopolysaccharide(LPS)and D-galactosamine(D-GalN).Methods One hundred and fifty C57BL/6 male mice were divided into 5 groups: phosphate buffered solution(PBS)pretreatment group,negative control plasmid pretreatment group,TS4 pretreatment group,TS6 pretreatment group and TS7 pretreatment group.Acute liver injury was induced in mice by intraperitoneal coinjection of LPS(10 ng/g)and D-GalN(1 mg/g).In vivo delivery of siRNA was performed via the tail vein by hydrodynamic injections(50 μg siRNA dissolved in 1 mL PBS)24 h and 48 h before coinjection of LPS and D-GalN. Expression of TLR-4 in liver tissues was measured by immunohistochemistry.The changes of TLR-4,tumor necrosis factor(TNF)-α and macrophage nflammatory protein(MIP)-2 mRNA levels in liver tissues were determined by reverse transcriptasepolymerase chain reaction(RT-PCR)analysis.MIP-2 and TNF-α concentrations in the sera of mice were determined by enzyme-linked immunosorbent assay(ELISA). Levels of alanine transaminase (ALT) and aspartate transaminase(AST) in serum were measured by standard autoanalyzer techniques. Liver pathological changes were observed by haematoxylin-eosin staining, while cell apoptosis levels in liver were determined by terminal deoxynucleotidyl-mediated-dUTP nick end labeling (TUNEL)assay. The difference of survival rates in 5 groups was analyzed by Fisher's exact probability test.ResultsPretreatment with TLR-4 siRNA down-regulated the TLR-4 mRNA and protein expressions,and significantly decreased the mortality and liver injury caused by coinjection of LPS and D-GalN in C57BL/6 mice.TLR-4 siRNA significantly down-regulated the TNF-α and MIP-2 mRNA expression and cytokine levels as determined by RT-PCR and ELISA,respectively. TLR-4 siRNA abrogated hepatocyte necrosis and inflammatory infiltration and also remarkably reduced serum concentrations of transaminases. The percentage of TUNEL-positive hepatocytes was significantly reduced in TLR-4 siRNA pretreatment group(TS4 pretreatment group: 0.065±0.015 vs PBS pretreatment group; 0.346±0.062,P＜0.05).ConclusionIt suggest that inhibition of TLR-4 expression by TLR-4 siRNA may provide potential application value for preventing liver injury.

Objective To analyze of CD4+ CD25high regulatory T cells(Treg)in peripheral blood of chronic HBV patients and its correlation with multiple clinical indicators.Methods Thirty-five hepatitis B virus(HBV)infected patients in this study were divided into four different clinical types:HBsAb+group(n=5),inactive hepatitis group(n=8),chronic hepatitis group(n=12),and immune tolerance group(n=10).The number of CD4+CD25high Treg and related T cells subgroup in CD3/CD4/CD8 was thoroughly examined by flow cytometry in peripheral blood of HBV infected patients and the healthy contrast group(n=12).Serum HBV markers were determined by commercial ELISA kits.Serum HBV DNA was quantified by commercial real-time PCR kit.Statistical differences were studied to investigate the correlations between CD4+CD25high Treg and different clinical types of HBV infection and clinical indicators.Results The absolute counts of CD25high Treg and its frequency in CD4+ T cells were similar between HBV infected patients [(12.35±6.48)/μ,(1.82±0.87)%]and health controls[(8.91±3.11)/μl,(1.35±0.39)%],P＞0.05.The frequency of CD25high Treg in CD4+ T cells from the immune tolerance group was significantly higher than that of the HBsAb+ group,chronic hepatitis group,and the healthy contrast group(P＜0.05).The absolute counts of CD25high Treg from the immune tolerance group were significantly higher than the healthy control group(P＜0.05),and the frequency of CD25high Treg in CD4+ T cells is negatively correlated to the ALT level(r=-0.418,P=0.038),positively correlated to CD4/CD8 ratio(r=0.344,P=0.021),no correlation to the HBV DNA level(r=0.118,P＞0.05).The absolute counts of CD25high Treg were positively correlated to CD4/CD8 ratio(r=0.360,P=0.015),no correlation to ALT level and HBV DNA level(r=-0.211,r=0.060,P＞0.05).Conclusion CD4+ CD25high Treg may play a role in immunopathogenesis of chronic HBV infection.