Objective:In order to understand the current situation of air toxic substances without occupational exposure limits (OELs) in the workplace in the Germany GESTIS Substance Database, and to provide an effective reference for formulating OELs of corresponding toxic substances and improving health standards.Methods:From March 2022 to May 2023, based on the standard of GBZ 2.1-2019 Occupational Exposure Limits for Hazardous Agents in the Workplace-Part 1: Chemical Hazardous Agents, air toxic substances without OELs in the standard of GBZ/T 300.1-2017 Determination of Toxic Substances in Workplace Air-Part 1: General Principles were screened out, then corresponding OELs in other countrie/regions were queried through the Germany GESTIS Substance Database.Results:Among the 333 kinds (classes) of air toxic substances in 160 parts of GBZ/T 300.1-2017 standard, 48 kinds (classes) of air toxic substances were screened out and had not yet been formulated OELs in GBZ 2.1-2019 standard. By querying the Germany GESTIS Substance Database, it was found that among the 48 kinds (classes) of air toxic substances, 35 kinds (classes) of air toxic substances had both 8-hour occupational exposure limit and short-term occupational exposure limit, 4 kinds (classes) of air toxic substances had 8-hour occupational exposure limit but no short-term occupational exposure limit, 9 kinds (classes) of air toxic substances hadn't been retrieved any OELs. In addition, standard test methods of 7 kinds of air toxic substances hadn't been published in the present, including trimethylchlorosilane, trimethylbenzenes, cumene, chloroethane, chloropropane, dibromoethane and acetophenone.Conclusion:In the process of formulating or revising the standards of GBZ 2.1-2019 and GBZ/T 300, the latest published OELs in the Germany GESTIS Substance Database could be used as a reference basis.

Objective:In order to understand the current situation of air toxic substances without occupational exposure limits (OELs) in the workplace in the Germany GESTIS Substance Database, and to provide an effective reference for formulating OELs of corresponding toxic substances and improving health standards.Methods:From March 2022 to May 2023, based on the standard of GBZ 2.1-2019 Occupational Exposure Limits for Hazardous Agents in the Workplace-Part 1: Chemical Hazardous Agents, air toxic substances without OELs in the standard of GBZ/T 300.1-2017 Determination of Toxic Substances in Workplace Air-Part 1: General Principles were screened out, then corresponding OELs in other countrie/regions were queried through the Germany GESTIS Substance Database.Results:Among the 333 kinds (classes) of air toxic substances in 160 parts of GBZ/T 300.1-2017 standard, 48 kinds (classes) of air toxic substances were screened out and had not yet been formulated OELs in GBZ 2.1-2019 standard. By querying the Germany GESTIS Substance Database, it was found that among the 48 kinds (classes) of air toxic substances, 35 kinds (classes) of air toxic substances had both 8-hour occupational exposure limit and short-term occupational exposure limit, 4 kinds (classes) of air toxic substances had 8-hour occupational exposure limit but no short-term occupational exposure limit, 9 kinds (classes) of air toxic substances hadn't been retrieved any OELs. In addition, standard test methods of 7 kinds of air toxic substances hadn't been published in the present, including trimethylchlorosilane, trimethylbenzenes, cumene, chloroethane, chloropropane, dibromoethane and acetophenone.Conclusion:In the process of formulating or revising the standards of GBZ 2.1-2019 and GBZ/T 300, the latest published OELs in the Germany GESTIS Substance Database could be used as a reference basis.

The utilization of optimal orthodontic force is crucial to prevent undesirable side effects and ensure efficient tooth movement during orthodontic treatment.However,the sensitivity of existing detection techniques is not sufficient,and the criteria for evaluating optimal force have not been yet established.Here,by employing 3D finite element analysis methodology,we found that the apical distal region(A-D region)of mesial roots is particularly sensitive to orthodontic force in rats.Tartrate-resistant acidic phosphatase(TRAP)-positive osteoclasts began accumulating in the A-D region under the force of 40 grams(g),leading to alveolar bone resorption and tooth movement.When the force reached 80 g,TRAP-positive osteoclasts started appearing on the root surface in the A-D region.Additionally,micro-computed tomography revealed a significant root resorption at 80 g.Notably,the A-D region was identified as a major contributor to whole root resorption.It was determined that 40 g is the minimum effective force for tooth movement with minimal side effects according to the analysis of tooth movement,inclination,and hyalinization.These findings suggest that the A-D region with its changes on the root surface is an important consideration and sensitive indicator when evaluating orthodontic forces for a rat model.Collectively,our investigations into this region would aid in offering valuable implications for preventing and minimizing root resorption during patients'orthodontic treatment.

Objective:To analyze the characteristics of patients with chronic rhinosinusitis (CRS) in the South China region based on pathological tissue biomarkers for regional comparison.Methods:The study population consisted of CRS in-patients in the First Affiliated Hospital of Sun Yat-sen University from October 2019 to June 2022. Among all the 181 cases, 123 of them were male and 58 were female, with an average age of 40. Retrospectively collected clinical data included demographic information, preoperative symptom scores, preoperative endoscopic images, preoperative paranasal sinus computed tomography scanning images, and inflammatory serological features. In addition, 52 variables of pathological tissue biomarkers including cytokines, chemokines and remodeling factors were collected for analysis. Cluster analysis was performed on the integrated data of training set through centroid-based clustering algorithm, and the inflammatory characteristics, post-operation control status, and airway diseases comorbidity of each endotype were analyzed. R project (version 4.2.2) was used in statistical analysis.Results:Cluster analysis divided 181 patients with CRS into 4 endotypes. Cluster 1 ( n=101, 55.80%) showed a locally low inflammatory status. Cluster 2 ( n=23, 12.71%) showed a mixed type of inflammation with predominantly neutrophilic inflammation and tissue remodeling. Cluster 3 ( n=11, 6.08%) was characterized by type Ⅱ inflammation without tissue remodeling. Cluster 4 ( n=46, 25.41%) was mainly characterized by type Ⅱ inflammation with tissue remodeling, showing higher comorbidity rate of asthma and allergic rhinitis. This cluster presented more severe symptoms, significant olfactory dysfunction, extensive overall inflammation based on objective examination results, a notable increase in total eosinophil count and proportion in peripheral blood, and the highest uncontrolled rate observed one year post-surgery. In comparison to other regions, the endotype classification of CRS in Southern China was characterized by a predominant pattern of locally low inflammatory status, a moderate level of type Ⅱ inflammation with tissue remodeling, and a lesser presence of neutrophilic inflammation. Conclusion:CRS distribution in Southern China is mainly characterized by low inflammatory endotype and type Ⅱ inflammation with tissue remodeling. The latter shows more severe clinical manifestations and higher uncontrol rate after surgery.

BackgroundPatients with schizophrenia are at high risk of suffering from metabolic syndrome. Most previous studies on the influencing factors of metabolic syndrome focused on the inpatients and limited ones on patients dwelling in community. ObjectiveTo explore the influencing factors at different risk levels of metabolic syndrome in community-dwelling patients with schizophrenia in Guangzhou， so as to provide references for future interventions on metabolic syndrome in this patient population. MethodsIn November 2021， 3 339 patients with schizophrenia who were registered in and administered by Guangzhou Mental Health Information System were included. All these patients had finished the physical examination in 2020， and whether they had metabolic syndrome was assessed basing on Guideline for the prevention and treatment of type 2 diabetes mellitus in China （2020 edition）. Patients were divided into high-risk group （n=423）， critical group （n=1 524） and metabolic syndrome group （n=1 392） according to the Chinese expert consensus on the management of metabolic syndrome in patients with schizophrenia. Multiple logistic regression analysis were performed on the risk factors of metabolic syndrome in community-dwelling patients with schizophrenia. ResultsThe prevalence rate of metabolic syndrome in community-dwelling patients with schizophrenia was 41.69%. Univariate analysis showed that the results in gender （χ²=44.610）， age （χ²=55.992）， marriage status （χ²=30.755）， illness course （χ²=25.913） and body mass index （χ²=829.265） were significantly different among the three groups （P<0.01）. Kruskal-Wallis H test showed that the levels of waist circumference （H=920.331）， systolic blood pressure （H=436.673）， diastolic blood pressure （H=393.337）， fasting blood glucose （H=807.304）， triglyceride （H=1 134.125） and high-density lipoprotein cholesterol （H=593.615） among the three groups were significantly different （P<0.01）. Logistic regression analysis showed that age ≥50 （OR=1.761， 95% CI： 1.087~2.853）， overweight （OR=2.418， 95% CI： 1.862~3.140） and obesity （OR=57.903， 95% CI： 14.340~233.802） were risk factors contributing to high-risk patients becoming critical population （P<0.05 or 0.01）. Female gender （OR=1.295， 95% CI： 1.034~1.622）， aged 40~49 （OR=2.597， 95% CI： 1.582~4.263）， age ≥50 （OR=4.392， 95% CI： 2.609~7.395）， overweight （OR=7.844， 95% CI： 6.018~10.223） and obesity （OR=426.785， 95% CI： 105.724~1 722.839） were risk factors for high-risk patients developing into metabolic syndrome population （P<0.05 or 0.01）. ConclusionThe prevalence rate of metabolic syndrome is higher in community-dwelling patients with schizophrenia. Female gender， older age， overweight and obesity would increase the risk of metabolic syndrome in schizophrenic patients. ［Funded by Health Science and Technology Project in Guangzhou （number， 20221A010028）］

Primary hypomagnesemia with secondary hypocalcemia(HSH) is a rare cause of hypoparathyroidism. This article presents a case of a 26-year-old male with recurrent generalized weakness and tetany, and a literature review of diagnosis and treatment of primary HSH. The biochemical tests revealed the patient had severe hypomagnesemia, mild hypocalcemia, hypokalemia, and hypoparathyroidism. Transient receptor potential melastatin-6(TRPM6) gene mutation were detected by gene test, which confirmed the diagnosis of primary HSH. The patient had been treated with long term oral magnesium supplementation, who remained asymptomatic during the follow-up. Primary HSH is a rare autosomal-recessive disorder caused by mutations in the TRPM6 gene which encoding a magnesium permeable channel expressed in the intestine and the kidney. The primary defect is impaired intestinal absorption of magnesium with secondary renal excretion, leading to a series of clinical symptoms. The treatment is mainly through lifelong magnesium supplementation.

The intestinal microbiota refers to the microbial group that exists in the intestine, and its composition disorder may affect human health. Many studies have found that intestinal microbiota and their metabolites may be closely related to the pathologies of Alzheimer′s disease (AD) through the gut-brain axis. This article will review the roles and possible mechanisms of lipopolysaccharide, functional bacterial amyloid proteins and bile acids, which are common metabolites of intestinal microbiota, in the pathogenesis of AD, and provide valuable information for exploring the pathogenesis of AD.

Objective:The aim of the study is to investigate the inter-observer and intra-observer precision in manually segmentation of organs-at-risk(OARs) for cervical cancer on the basis of MR image, and to preliminarily explore sequence selection designed for radiotherapy planning.Methods:Thirty cervical cancer patients scanned by MR-sim from 2016 to 2018 in the department of radiotherapy of Sun Yat-sen university cancer center were retrospectively analyzed. T1WI, T1dixonc and T2WI sequence from MR-simulator were selected and imported into Monaco planning system. Manual segmentation of 5 organs-at-risk (bladder, rectum, anal canal, and left/ right femoral head) was done by 2 independent experienced physicians on three sequences acquired from these patients. A month later, the second segmentation of the OARs in the T1WI sequence was done by one of the two physicians. Dice similarity coefficient (DSC), Hausdorff distance (HD) and position difference(Δ x, Δ y, Δ z) of each OAR were used to analyze the robustness of inter-observer and intra-observer segmentation OARs. Results:The HD values of five OARs segmentation by the two physicians in T1WI, T1dixonc and T2WI sequences and the same physician in T1WI at different time were all less than 2 mm; the position differences were less than 5 mm. The DSC values, HD values and difference position values of the two physician and the same physician at different time was positively correlated with the volume of OARs ( R=0.178-0.582, P<0.05). Due to the small volume of the anal canal (7.385±1.555) cm 3, the DSC values were less than 0.7 and the performance was slightly worse. The average DSC values of other OARs were all greater than 0.82. Comparing the DSC, HD and position differences of OARs in the three sequences, DSC values of rectum, left / right femoral head and bladder, HD values of left/right femoral head and rectum, and Δ z axis difference of anal canal and right femoral head of T1WI sequence were better than T1dixonc ( t=-3.116-3.604, P<0.05); DSC value of rectum and HD value of anal canal in T1WI sequence were better than T2WI sequence( t= 2.934, 3.677, P<0.05 ); T1dixonc sequence rectal DSC, right femoral head Δ z axis difference were slightly better than T2WI( t=6.806, 2.130, P<0.05 ). T2WI sequence bone tissue (left/right femoral head) stability was better than T1WI, T1dixonc, and the difference was statistically significant ( t=-6.580-6.542, P<0.05). Conclusions:From three index of DSC, HD and position difference, the robustness of inter-observer and intra-observer segmentation of bladder, rectum and femoral head are fine based on MR sequence, followed by anal canal. In addition, the robustness of OARs segmentation by T1WI sequence is better than that of T1dixonc and T2WI sequence.

Objective: To investigate the characteristics of hearing loss in occupational noise-exposed workers in automotive manufacturing industry. Methods: According to Technical Specifications for Occupational Health Surveillance (GBZ188-2014) , 530 noise-exposed workers were examined for health and pure tone audiometry during January to June, 2017, and the data were collected for analysis. Poisson regression analysis was used to analysis the relationship between work age and hearing loss. Results: After correction of age and gender, pure-tone threshold of 500, 1 000, 2 000, 3 000, 4 000, 6 000 of the noise-exposed workers in the <3 year-exposure group were 20.15±3.60, 18.80±3.43, 18.54±3.38, 19.10±4.03, 20.32±6.79, 23.48±8.92 dB (A) ; the values in the 3-10 year-exposure group were 20.96±5.38, 19.25±4.76, 19.22±5.29, 20.17±7.50, 21.36±8.88, 25.39±11.60 dB (A) ; the values in the >10 year-exposure group were 20.18±3.67, 18.34±3.60, 18.36±4.25, 18.49±4.41, 20.32±9.24, 22.50±9.57 dB (A) . Poisson regression analysis showed that the relative risk (RR) of hearing loss of the noise-exposed workers compared with the noise-free workers was 4.38 (P<0.05) . Conclusion The noise-exposed workers in automotive manufacturing industry revealed hearing loss, which was associated with their actual working age of noise exposure.

Objective To evaluate the detection performance of the cobas8000 c702 fully automatic biochemical analyzer for de‐tecting the second generation Roche urine trace albumin (ALBU2) .Methods (1) The precise evaluation :with the allowable error stipulated by CLIA 88 as the basis ,the requirements were the repeat precision <1/4TEa ,and intermediate precision <1/3TEa;(2) the linear range and the evaluation of the reportable range :the EP6‐A scheme was adopted ,and extend to calculate the average re‐covery rate of dilution ,the clinical reportable range was evaluated by the average dilution recovery of 90% -110% ;(3) the carry o‐ver pollution assessment :the carry over pollution of serum albumin on urine trace albumin detection was evaluated by the judgment standard of carry over pollution rate of 0 .5% ;(4)the methodological comparative analysis :with SIEMENS BN Ⅱas the reference system ,the Roche Cobas 8000 C702 and the BN2 results were performed the correlation contrastive analysis .Results The repeat precision :low concentration CV=1 .98% .high concentration CV=1 .64% ;intermediate precision :low concentration CV=4 .35% , high concentration CV=1 .20% ;the linear range verification :the measurement range 5 .6-413 .55 mg/L ;clinical reportable range :in the maximum diluted multiples of 30 times ,the clinical reportable range was 5 .6-12 406 .5 mg/L ;the carry over pollution rate :serum albumin (42 .6 g/L) on urine trace albumin(6 .9 mg/L) ,the carry over pollution rate was 0 .28% ;the indoor comparison :in the concentration within 200 mg/L ,the regression line was Y=0 .896 X+5 .049 ,the correlation coefficient r2 =0 .994 4 ,the system shift was passed at the medical decision level .When the specimen concentration within 201-413 .55 mg/L ,the regression line was Y=0 .848X-10 .44 ,the correlation coefficient r2 =0 .917 ,the system shift was not passed at the medical decision level .Conclusion The detection of the Roche ALBU2 in the Cobas 8000 C702 platform can meet the clinical needs ,the comparison among different instruments has difference in different concentration ranges ,therefore the independent reference ranges should be established ac‐cording to the each instrument system .