[The cell nuclear damage probably induces chronic refractory diseases].

The cell nuclear damage is mainly caused by the radiation and various carcinogenic compounds, the essence of the damage is molecular adhesion fracture and chemical modification. After nuclear damage, the cells whose nuclei may be abnormal in morphology, structure and function, then become a kind of morbid cells or defective cells. The cell nuclear damage can affect gene expression and regulation, leading to dysfunctions or abnormalities of transcription and protein synthesis, which results in aging and induces various chronic refractory diseases, such as hypertension, atherosclerosis, diabetes, Alzheimer's disease, autoimmune diseases, and so on. The cell nuclear damage can also affect the state of cell differentiation and lead to restart of genes related to division and proliferation, thus inducing cancer. The cancer cells are derived from the cells with nuclear abnormalities, and the biological behavior or characteristics of cancer cells (shedding and metastasis, immune tolerance, uncontrolled, loss of contact inhibition, etc.) are derived from cells with nuclear abnormalities. This article reviewed the chronic refractory diseases caused by nuclear damage and their mechanisms, which provided a new idea for occupational health and toxicology research, as well as a new method and strategy for occupational disease prevention and treatment.

[Clinicopathological characteristics related to Miller/Payne grading system of breast carcinoma after neoadjuvant therapy and establishment of novel prediction models].

Objective: To investigate the correlation between clinicopathological features and Miller/Payne (MP) grading system of breast carcinoma after neoadjuvant treatment and to establish novel prediction models. Methods: A total of 1 053 cases of invasive breast carcinoma NOS that undertaken neoadjuvant treatment according to Guidelines of CSCO for Breast Cancer were selected at the Key Laboratory of Carcinogenesis and Translational Research, Peking University Cancer Hospital & Institute from September 2016 to September 2019, and the clinical, pathologic data, MP grading and immunohistochemical staining were evaluated. Statistical analysis was conducted using R software. Several novel computer models on prediction of MP grading were established and validated. Results: Among 1 053 patients who accepted neoadjuvant treatment, 316 patients (316/1 053, 30%) were evaluated as MP5 postoperatively, and 737 patients (737/1 053, 70%) did not meet MP5 level. MP5 had significant association with histological grade, ER and PR expression, HER2 status, Ki-67 index and molecular classification (P<0.05). Univariate/multivariate logistic regression analyses further showed that the above clinicopathological features were also independent influencing factors of MP5 grade; five-fold cross-validation was used to evaluate the performance of the models, and the sensitivity and specificity of different models were obtained. Conclusions: MP grading of invasive breast carcinoma NOS after neoadjuvant treatment is associated with high histological grade, negative ER and PR expression, HER2 positivity, high Ki-67 index and molecular classification, which are independent influence factors. GBM model recommended through comparison can provide some help for clinical diagnosis and treatment.

[Relationship between pesticide exposure and lipid metabolism in population].

Objective: To investigate the effect of pesticides and herbicides on lipid metabolism. Methods: In November 2020, Based on the data of the national health and Nutrition Survey (NHANES) (2011-2014) , select the population aged 20~65 who have demographic information, pesticide use and data of four lipid metabolism indicators [total cholesterol (TC) , triglyceride (TG) , high density lipoprotein cholesterol (HDLC) and low density lipoprotein cholesterol (LDLC) ] (n=3039) . The subjects were divided into insecticide group (320 people) and non insecticide group (2719) according to the use of insecticides, and herbicide group (156 people) and non herbicide group according to the use of herbicides. Results: Among the 3039 subjects, the males and female were 1509 (49.7%) and 1530 (50.3%) respectively. The males age was (39.7±12.0) years and the females age was (40.2±12.0) years The concentration of HDLC in the NHANES (55.4±15.0) mg/dl was lower than that of (58.2±14.2) mg/dL in the non herbicide group (P<0.05) (b=-0.044, P<0.05) . The results showed that the use of herbicides was related to the decrease of HDLC and the increase of LDLC and LDLC/HDLC in female population (b=-0.050, 0.062, 0.067, all P<0.05) . Conclusion: Herbicide exposure can cause the change of lipid metabolism, and the effect on female population is more obvious.

[Comparative analysis of work-related musculoskeletal disorders catalogues].

Work-related musculoskeletal disorders (WMSDs) refer to musculoskeletal disorders caused by work or work as the main cause, which are characterized by high prevalence and heavy burden of disease as a global problem. The classification and catalog of occupational diseases is of great significance for guiding the prevention and control of occupational diseases and safeguarding the rights and interests of workers. The types of WMSDs included in the list of occupational diseases vary greatly from country to country, and the regulations on specific pathogenic factors are also inconsistent. By sorting out and analyzing the lists and characteristics of WMSDs at home and abroad, and using the International Statistical Classification of Diseases and Related Health Problems (ICD-10) in occupational health to standardize of WMSDs in various countries, which would lay the foundation for future multi-country WMSDs occupational health registration and disease burden research, and provide a reference for China to revise the WMSDs list.

[Expression of SQSTM1 in papillary thyroid carcinoma and its influence on invasion, migration and proliferation of papillary thyroid cancer cells].

Objective: To investigate the expression of SQSTM1 in thyroid papillary carcinoma and its influence on the invasion and migration of thyroid papillary carcinoma cells TPC-1. Methods: From April to June 2019, cancer tissues and adjacent tissues of 21 cases with thyroid papillary carcinoma in the First Affiliated Hospital of Zhengzhou University were collected, and the expression of SQSTM1 was detected by RT-qPCR. SQSTM1 knockdown cell line SQSTM1-KD-TPC-1 was constructed in TPC-1 cells by lentivirus transfection. RT-qPCR was used to detect SQSTM1 expression in TPC-1 cells and SQSTM1-KD-TPC-1 cells. The changes of invasion and migration before and after SQSTM1 knockdown in TPC-1 cells were detected by transwell test. The proliferation of TPC-1 and SQSTM1-KD-TPC-1 cells were detected by MTT and clone formation test. RT-qPCR was used to detect the gene expression of proliferation related proteins. Results: The expression of SQSTM1 in papillary thyroid carcinoma tissues was significantly higher than that in normal adjacent tissues, and 76.2%(16/21) of the petients showed high mRNA expression. Knock down SQSTM1 significantly inhibited the ability of tumor proliferation, invasion and migration, and the expression of proliferation-related proteins were significantly decreased (P<0.01), indicating that SQSTM1 was involved in the regulation of proliferation related pathway mechanism. Conclusion: SQSTM1 significantly promotes invasion, migration and proliferation in thyroid papillary cancer cells TPC-1 and may be a potential gene therapy target.

[The reference intervals of thyroid functional indicators in pregnant population in Xi'an].

To establish reference intervals for thyroid functional indicators in early (T1), mid-term (T2), and late stage (T3) pregnancy in a population of women in Northwestern China. A cross-sectional study was conducted on 620 pregnant women. Subjects were recruited through a questionnaire where apparently healthy women were selected. Serum thyroid stimulating hormone (TSH3), total triiodothyronine (TT3), total thyroid hormone (TT4), free triiodothyronine (FT3), and free thyroid hormone (FT4) were detected using the Beckman Unicel DXI 800 automatic chemiluminescence analyzer (the third-generation TSH detection reagent for TSH3),and the reference intervals of different gestation periods were established. The results showed that the reference intervals of TSH3 in T1, T2, and T3 were 0.05-4.59, 0.61-6.01, and 0.63-4.78 mIU/L, respectively; TT3 were 1.62-2.97 nmol/L, 1.59-2.95 nmol/L, and 1.45-2.70 nmol/L, respectively; TT4 were 95.49-185.00 nmol/L, 92.70-181.54 nmol/L, and 77.93-155.09 nmol/L, respectively; FT3 were 3.18-5.22 pmol/L, 2.78-4.67 pmol/L, and 2.51-4.18 pmol/L, respectively; and FT4 were 7.72-12.97 pmol/L, 6.90-1.09 pmol/L, and 5.63-9.85 pmol/L, respectively. All thyroid function indexes had statistically significant differences between the three stages of pregnancy (TSH:H=30.879,P<0.01;FT3:H =153.827,P<0.01;FT4:H =229.967,P<0.01;TT3:H =36.484,P<0.01;TT4:H =58.531,P<0.01). 20 independent samples were collected to verify the reference intervals of TSH, FT3, FT4, TT3 and TT4 for three trimesters of pregnancy, and all of them passed.

[Radial artery thrombosis in optical coherence tomography guided transradial coronary angiography and percutaneous coronary intervention in acute coronary syndrome patients and its risk factors analysis].

Objective: To observe the radial artery thrombosis (RAT) during transradial coronary angiography (CAG) and/or percutaneous coronary intervention (PCI) by optical coherence tomography (OCT), and to investigate the risk factors of RAT during the CAG and/or PCI. Methods: In this retrospective study, we consecutively reviewed the radial artery OCT examination results of the patients who underwent OCT guided transradial CAG and/or PCI for acute coronary syndrome in heart center of Beijing Luhe hospital, Capital Medical University from October 2017 to July 2018. The incidence of RAT was observed. The patients were divided into the RAT group and non-RAT group, clinical data were collected and compared. Moreover, the types and distributions of thrombus in radial artery as well as the acute radial artery injuries under OCT were observed. Univariate analysis followed by multivariate analysis were performed to identify potential risk factors. The radial artery patency and ischemic symptoms of the involved limb were followed up at the 24-hour and the 1-month after procedure. Results: A total of 107 patients were included, the age was (58.1±12.5), and 78.5% were male (n=84). The incidence of RAT was 26.2% (n=28, 95%CI 17.9%-34.5%), and the main type of thrombus was white thrombus (n=15, 53.6%). The commonest position of RAT was the proximal portion of radial artery (n=17, 60.7%). The median thrombus volume was 0.05(0.03, 0.38) mm3, and the median thrombus score was 6.5 (3.3, 13.8). In univariate analysis, the frequency of acute radial artery injury and use of bivalirudin were significantly higher and the procedure time was significantly longer in RAT group than those in non-RAT group (all P<0.05). Multivariate regression analysis showed that the radial artery acute injury (OR=5.82, 95%CI: 2.09-16.20, P=0.001) and the procedure time (OR=1.04, 95%CI: 1.01-1.06, P=0.006) were independent risk factors of RAT. Rate of radial artery occlusion at 24 hours follow-up was similar between RAT and non-RAT group (7.14%(2/28), vs. 10.13%(8/79), P=1.000). None of the patients complicated severe ischemic symptom of the operative limb. Conclusions: RAT is a high frequency access complication during transradial coronary intervention. This phenomenon can be accurately observed by OCT. Acute radial artery injury and prolonged procedure time are risk factors of RAT during transradial coronary intervention.

[Screening of candidate genes related to low-dose ionizing radiation based on transcriptome-proteome correlation research techniques].

Objective: To identify the related genes of low-dose ionizing radiation on basis of association analysis of transcriptome and proteome data, and provide new clues for the molecular mechanism of low-dose radiation (LDR) effect. Methods: In March 2018, healthy human peripheral blood was used as materials for transcriptome sequencing and proteome analysis after exposure to radiation at 150 mGy (treatment group) and no radiation (control group) , with three samples in each group. The total RNA and protein were extracted and then correlation analysis of transcriptomic and proteomic were performed to determine LDR effect-related genes, and after that, the biological process and molecular function were analyzed. Results: A total of 486 genes and 266 proteins were identified differentially expressed between treatment group and control group, respectively. Twelve genes and related proteins were found correlated (P<0.05) . The overall correlation between quantitative protein and gene was low (rs=0.0034) , the differential gene with the same change trend was positively correlated with protein expression (rs=0.6786) , and the differential gene with the opposite change trend was negatively correlated with protein expression (rs=-0.1000) . Seven differentially expressed genes (DEGs) showed the same trend as proteins, among which FBXO7 and SNCA were up-regulated as well as ORM1, ORM2, HIST1H4J, HBZ and LYZ were down-regulated. Five DEGs showed the opposite trend as proteins, including SLC4A1, BCAM, C4B_2, KEL, TGM2 up-regulated in transcription level and down-regulated in protein expression level. These DEGs were involved in various biological processes such as immune system regulation, signal transduction, enzyme activity regulation, transmembrane transport, defense, transcription and DNA repair, which indicated their important roles in response to LDR in human peripheral blood. Conclusion: Twelve candidate genes related to LDR effect and their corresponding expressed proteins are screened by the correlation research of transcriptome and proteome data, which provides new clues for the further study of the mechanism of LDR effect.

[Pisussion on noise exposure level measurement and risk assessment of typical posts in coal-fired power plants].

Objective: To study the group noise exposure level of typical coal-fired power plants and explore the establishment of risk assessment methods for noise exposed posts. Methods: In April 2020, 295 typical workers in 11 coal-fired power plants were selected as the study subjects. The noise exposure dose of typical posts and the proportion of exposure groups under different exposure doses were analyzed, and the risk assessment based on the dose-response relationship was conducted. Results: The exposure level of typical noise posts in coal-fired power plants was (84.24±4.10) dB (A) , and the over-standard rate was 44.07% (130/295) . The highest noise over-standard rate in main posts were desulfurization inspectors (51.52%) , followed by steam turbine inspectors (47.92%) and belt inspectors (46.32%) . Taking 30 years as an example, the incidence rate of occupational noise deafness of noise-exposed posts in coal-fired power plants was 12.30%. The position with the highest incidence rate was belt inspector (13.21%) , followed by steam turbine inspector (12.97%) , desulfurization inspectors (12.42%) , boiler inspectors (11.59%) and chemical water inspectors (6.89%) . Conclusion: The risk of noise exposure in coal-fired power plants is relatively high. Comprehensive control measures are recommended to effectively reduce the risk of noise deafness.

[A non-targeted metabolomics study on urine of occupational exposure people with titanium dioxide nanoparticles].

Objective: To investigate the effects of titanium dioxide nanoparticles (TiO(2) NPs) on urine metabolites in occupationally exposure people based on metabolomics technology, and to explore the mechanism of early health effects of TiO(2) NPs on occupational exposure. Methods: In October 2019, the TiO(2) NPs occupational exposure population was selected as the research object, of which 64 people were in the exposure group who had been engaged in TiO(2) NPs exposure positions for more than 1 year; the control group was 62 people, who were logistics administrative staff of the same company. The urine of the research subjects before class was collected, using the ultra-high performance liquid chromatography time-of-flight mass spectrometer to collect the metabolism data of the urine, Progenesis QI software for data preprocessing and metabolite identification, SIMCA-P software for the principal component analysis of the data and potential biomarkers screening, MetaboAnalyst 4.0 software for metabolic pathway enrichment analysis. Results: The urine metabolism profile of workers in the exposure group was different from the control group, and 44 potential biomarkers were screened and identified. These potential biomarkers were significantly enriched in three pathways (P<0.05) , namely D-arginine and D-ornithine metabolism pathway, nitrogen metabolism pathway and D-glutamine and D-glutamate metabolism pathways. Conclusion: The occupational exposure of TiO(2) NPs can affect the concentration of metabolites in people urine and metabolic pathways, which provides a direction for the study of occupational hazard mechanisms of TiO(2) NPs and the monitoring of health risks.

[Metabolomics study of urine with Benzene, Toluene and Xylene combined exposure based on ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry].

Objective: To study the effects of combined occupational exposure of benzene, toluene, and xylene on human metabolism at an overall level, and to screen biomarkers related to the combined occupational exposure of benzene, toluene, and xylene, and to explore the mechanism of early health effects preliminarily caused by combined occupational exposure of benzene, toluene, and xylene by identification of biomarkers and retrieval of metabolic pathways. Methods: A shoe-making company was selected as the research site. Twenty subjects for the exposed group and the control group were selected separately, and urine of the subjects was collected. The metabolic profiles of the samples were collected by liquid chromatography time-of-flight mass spectrometry, and professional metabolomics and multivariate statistical analysis software were used to establish PCA and OPLS-DA analysis models to screen potential biomarkers and identify biomarkers. Finally, based on the dynamic changes and trends of potential biomarkers between groups, the mechanism of body damage caused by benzene, toluene, and xylene was initially explored. Results: Urine metabolomics analysis showed that the metabolic profile of urine samples of the benzene, toluene, and xylene combined exposure group was different from that of the control group. 27 potential biomarkers that were closely related to the combined exposure of benzene, toluene, and xylene were screened and identified. These potential biomarkers were enriched in 16 metabolic pathways, of which 3 pathways were significantly enriched (P<0.05) , respectively, lysine metabolism, amino sugar metabolism, and nucleotide sugar metabolism. Conclusion: The metabonomics method can well reflect the changes in the metabolome of urine samples in the occupational population after the combined exposure of benzene, toluene, and xylene, which will help us better evaluate the risk of combined exposure of benzene, toluene, and xylene and prevent and control their health risks.

Effects of steam explosion pretreatment and Lactobacillus buchneri inoculation on fungal community of unensiled and ensiled total mixed ration containing wheat straw during air exposure.

AIM: To compare the effects of steam explosion and Lactobacillus buchneri inoculation on fungal community in ensiled total mixed ration (TMR) during aerobic exposure. METHODS AND RESULTS: The TMRs were prepared using wheat straw with or without steam explosion, sweet potato residue, lucerne hay, maize meal and soybean meal, and ensiled with or without L. buchneri inoculation. Fungal communities were detected by high-throughput sequencing. All ensiled TMRs were well ensiled and steam explosion has a major effect on improving aerobic stability. The fungal species, such as Xeromyces bisporus and Cryptococcus victoriae, that dominated in the TMR decreased after ensiling, with a concomitant increase in Candida humilis, Pichia kudriavzevii, Aspergillus flavus and Phanerochaete chrysosporium. Most mould species decreased, with C. humilis and P. kudriavzevii dominating during aerobic exposure. CONCLUSION: Steam explosion could improve the aerobic stability in ensiled TMR by inhibition of C. humilis. SIGNIFICANCE AND IMPACT OF THE STUDY: High-throughput sequencing used in this study provides insight into the fungal community in ensiled TMR during aerobic exposure, which could contribute towards elucidating the mechanism by which aerobic deterioration develops.

[Effects of ultrasonic bone curettes combined with high-speed drills in posterior laminectomy and decompression procedure for severe thoracic spinal stenosis].

Objective: To evaluate the safety and efficacy of the combined use of ultrasonic bone curette with the high-speed drill in posterior laminectomy and decompression procedure for severe thoracic spinal stenosis, and propose the optimal cutting position for ultrasonic bone curette during the laminectomy. Methods: By observing and measuring the parameters of thoracic pedicle, lamina, inner wall of the vertebral canal and their relation with the surrounding structures on cadavers, we provided a morphological marker for laminectomy by an ultrasonic bone curette. Data of 19 patients with severe thoracic spinal stenosis treated by posterior laminectomy and decompression were collected from June 2017 to June 2018 in Shanghai Changzheng Hospital. There were 11 males and 8 females, aged (50±6) years. The patients received laminectomy with the combined use of ultrasonic bone curette and the high-speed drill (Group A, n=10) or the use of ultrasonic bone curette alone (Group B, n=9). Operational time of decompressive laminectomy, blood loss, as well as perioperative complications such as durotomy, cerebrospinal fluid leak, injury of the nerve root and spinal cord were recorded in these two groups. The improvement of symptoms and the decompression width of the spinal canal were evaluated after operation. Two independent samples t-test was used for the comparison of two sets of continuous normal distribution data. Results: We had done the measurement in 6 cadavers. The mean distance between the boundary of cancellous-cortical bone of lamina and the inner wall of spinal canal was (0.9±0.4) mm, and the distance between the boundary of cancellous-cortical bone of pedicle and the inner wall of the spinal canal was (1.2±0.6) mm. For the surgeries in groups A, the mean laminectomy time for each segment was (4.4±0.5) min, the mean width of posterior laminectomy was (21.8±0.5) mm; and for the surgeries in group B, the mean laminectomy time for each segment was (5.0±0.5) min, the mean width of posterior laminectomy was (19.9±1.0) mm; there were significant differences in laminectomy time for each segment and the width of posterior laminectomy between the two groups (t=-2.391, 3.491, both P<0.05). There was one case of dura injury and one case of thoracic nerve root injury during the operation in group B. Conclusions: It is safer and more reliable for the combined use of ultrasonic bone curette with the high-speed drill in posterior laminectomy and decompression procedure for the severe thoracic spinal stenosis. The interface between the cortical bone and the medial edge of cancellous bone of the pedicle could be identified as the cutting mark for ultrasonic bone curette in this procedure.

[Investigation and analysis of occupational hazards and control measures in waste incineration power generation enterprises].

Objective: To investigate occupational hazards in waste incineration power generation enterprises. Methods: From May 2016 to September 2018, four garbage incineration power generation enterprises in different regions and scales were selected as the survey objects. Investigated and analyzed the types of occupational hazards, workplace distribution and occupational disease prevention facilities and the concentration (intensity) of major types of work and workplace occupational hazards were also improved Line detection and analysis. Results: Silica dust could be seen in slag tank, slag sorting and crusher operation position. The concentration of silica dust in each workplace fluctuates within 0.3-1.1 mg/m(3). Both the concentration of silica dust in the workplace and the time weighted average allowable concentration (C-TWA) of dust exposure of dust exposed workers were detected, but none of them exceeds the requirements of the national occupational exposure limit. Carbon monoxide, ammonia, nitrogen dioxide, hydrogen sulfide, non methane total hydrocarbon, formaldehyde, hydrogen fluoride, hydrogen cyanide, hydrochloric acid, sodium hydroxide and ozone were detected, but all meet the requirements of national occupational exposure limit. The 8-hour equivalent a sound level (L(ex·8h)) over 85 dB (A) mainly includes boiler, steam turbine, electrical inspector and auxiliary value of water treatment. Conclusion: The occupational hazards of waste incineration power generation enterprises are serious. Occupational health management and occupational health monitoring to reduce their occupational hazards to workers.

[The influencing effects of effort reward imbalance on sleep disorders among metro staff in Guangzhou].

Objective: To detect the prevalence of sleep disorders among metro staff and to analyze influencing effects of effort reward imbalance (ERI) on it. Methods: In January 2015, subway driver, dispatcher and station operator from Guangzhou subway were selected as the research object in the whole group sampling method. A total of 1200 questionnaires were distributed and 1124 were valid questionnaires, and the effective questionnaire recovery rate was 93.7%. Based on the effort reward imbalance questionnaire and the self-administered sleep questionnaire, the data of the general demographic characteristics, life satisfaction, occupational stress and sleep status of the respondents were collected. Epi.data3.1 and spss19.0 were used for analyzing. Results: A total of 1124 subway employees were surveyed, with an average age of (28±5) years; the working age was (4.5±3.6) years. ERI occupied 24.7% (278/1124) of the study population and sleep disorders as 42.2% (474/1124) . Single factor analysis showed that marital status, educational level, work position, life satisfaction and ERI could significantly influence sleep disorders of metro staff (P<0.05) . Logistic regression showed that higher effort (adjusted OR=2.56, 95%CI: 1.79-3.68) , lower reward (adjusted OR=1.90, 95%CI: 1.34-2.68) and ERI (adjusted OR=2.33, 95%CI: 1.69-3.22) could increase the risk of sleep disorders after the confounding factors were controlled. ERI (adjusted OR=2.89, 95% CI: 1.80-4.64) , and over commitment (adjusted OR=4.64, 95%CI: 2.81-7.68) could influence the risk of sleep disorders independently when over commitment was evaluated as a moderating variable. Conclusion: Occupational stress as ERI could influence the risk of sleep disorders among metro staff. The situation should not be neglected for occupational health of metro staff.

Sensitivity of resonance properties of all-dielectric multilayers driven by statistical fluctuations.

In photonics and emerging fields of quantum and topological materials, increasing demands are placed upon the state and control of electromagnetic fields. Dielectric multilayer materials may be designed and optimized to possess extremely sharp spectral and angular photonic resonances allowing for the creation of fields orders of magnitude larger than the exciting field. With enhancements of 104 and higher, the extreme nature of these resonances places high constraints on the statistical properties of the physical and optical characteristics of the materials. To what extent the spectral and angular shifts occur as a result of fluctuations in the refractive indices and morphologies of the involved low-loss subdomains have not been considered previously. Here, we present how parameter variations such as those caused by fluctuations in deposition rate, yielding bias, random and compensated errors, may affect the resonance properties of low-loss all-dielectric stacks.

EDACO, a derivative of myricetin, inhibits the differentiation of Gaoyou duck embryonic osteoclasts in vitro.

1. This study determined the effects of (E)-3-(2-(4-(3-(2,4-dimethoxyphenyl)acryloyl)phenoxy)ethoxy)-5,7-dimethoxy-2-(3,4,5-trimethoxyphenyl)-4H-chromen-4-one (EDACO) on the differentiation of Gaoyou duck embryonic osteoclasts cultured in vitro. 2. Bone marrow mononuclear cells (BM-MNC) were collected from 23-d-old Gaoyou duck embryos and induced by macrophage colony-stimulating factor and receptor activator of nuclear factor κB ligand in the presence of EDACO at different concentrations (i.e. 10, 20, 40, 80 and 160 µM). Tartrate-resistant acid phosphatase (TRAP) staining and resorption ability determination were conducted. 3. Results suggested that EDACO suppressed the shaping of positive multinucleated cells and the number of TRAP-positive cells in the 20, 40, 80 and 160 µM EDACO groups was significantly decreased (P < 0.05 or P < 0.01). Besides, the absorption activity of differentiated duck embryonic osteoclasts was significantly inhibited (P < 0.05) in both 80 and 160 µM EDACO groups. 4. Overall, EDACO can inhibit the differentiation of BM-MNC into mature osteoclasts in duck embryos.1.

[Determination of Cortisol in Saliva by Liquid Chromatography Tandem Mass Spectrometry].

Objective: To establish a liquid chromatography tandem mass spectrometry method to determine the cortisol in saliva. Methods: Take 0.5 ml saliva sample into a 2 ml centrifuge tube, add excess sodium chloride and 1ml acetonitrile to it, then vortex for 3 min, centrifuge for 10 min at 15 000 r/min, and take 800 µl of the upper layer to another centrifuge tube. Finally, the sample was concentrated by a vacuum concentrator and brought to 200 µl with the initial mobile phase. Then, the sample was analyzed by liquid chromatography tandem mass spectrometry. The target compound was quantified by external standard curve method. Results: The linear range of the method was 0.02-5.00 ng/ml, r=0.999 9, the method limit of the detection was 0.002 ng/ml, the method limit of quantitative was 0.02 ng/ml, and the spiked recoveries were 89.60%-98.60%. The intra-assay precision was 1.90%-3.30%, and the inter-assay precision was 4.20%-9.00%; samples could be stored at -20 °C for at least 14 days. The determination of cortisol could not be interfered by other endogenous substances in the sample. Conclusion: The method is simple in pretreatment, high sensitivity, good reproducibility and good recovery, and it is suitable for the quantitative analysis of cortisol in saliva for normal and occupationally stressed populations.

[Study on the effect of activated carbon on formaldehyde in clean workshop].

Objective: To study the effect of activated carbon on the purification of formaldehyde in the clean workshop return air purification device and its influencing factors. Methods: From May to June 2018, choosed 4 different commercial activated carbons (bamboo charcoal, 1-3 mm, 3-5 mm; coconut shell charcoal, 6-12 mesh, 8-16 mesh) to make 5 types of activated carbon purification net. In the simulated clean plant laboratory, the detection of occupational disease hazards was used to test the purification effect of different types of activated carbon purification nets on formaldehyde. Results: The purification effect of different types of activated carbon increased with the prolongation of purification time, and the difference was statistically significant (P<0.05) . Compared with other types of activated carbon, coconut shell charcoal (8-16 mesh, double layer) had the best purification effect, 15 min and 30 min purification efficiency was 58.72% and 85.20% respectively, and the difference was statistically significant (P<0.05) . The purification effect of double-layer coconut shell charcoal was better than single layer (P<0.05) . The purification effect of double-layer coconut shell charcoal (8-16 mesh) was better than double-layer coconut shell charcoal (6-12 mesh) , the difference was statistically significant (P<0.05) . Coconut shell charcoal (8-16 mesh, double layer) had better purification effect than bamboo charcoal (P<0.05) . Conclusion: Different specific surface area, particle size, and thickness of activated carbon have a certain effect on the purification effect of formaldehyde, and its selection has a certain significance in improving the occupational health protection level in the clean plant, solving the safe use of return air and reducing energy consumption.

[Determination of seven urinary metabolites of benzene, toluene and xylene by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry].

Objective: To develop a method using ultra-high performance liquid chromatography-triple quadrupole mass spectrometry to determine the urinary metabolites of benzene, toluene and xylene. The selected metabolites are S-phenylmercapturic acid (S-PMA) , trans, trans-muconic acid (t, t-MA) , 8-hydroxy-2 deoxyguanosine (8-OHdG) , hippuric acid (HA) , 2-methylhippuric acid (2-MHA) , 3-methylhippuric acid (3-MHA) and 4-methylhippuric acid (4-MHA) . Methods: The urine sample was pretreated using methanol to precipitate the proteins. HSS T3 chromatographic column was used to separate the metabolites. The mass spectrometric acquisition was carried out using multiple reaction monitoring (MRM) after ionization with ESI source. External standard method was used for quantification. Results: All the standard curves showed good linear relation, and r of the seven metabolites was all above 0.999. The detection limits and quantitative limits of the seven metabolites were 0.01-500 ng/ml and 0.02-1 000 ng/ml (based on the actual dilution ratio) , respectively. The average spiked recoveries of four loadings ranged from 85.8% to 109.9%. The intra-day and inter-day precisions were 0.2%-4.5% and 0.6%-9.5%, respectively. The samples can be kept for at least 14 days at both 4 ℃ and -20 ℃. Conclusion: This method is simple, rapid and highly sensitive with low cost, and its accuracy, precision and stability can meet the daily test requirements. It can be applied for the determination of urinary S-PMA, t, t-MA, 8-OHdG, HA, 2-MHA, 3-MHA and 4-MHA for the occupational population exposed to benzene, toluene and xylene.