Analysis of verification results of protective effects of hearing protectors in different industries / 中华劳动卫生职业病杂志

Objective: To get insight into the current practice of noise reduction effect of workers as they wore hearing protectors in different domestic enterprises and the possible affected factors. Methods: From October 2020 to April 2021, using a random sampling method, 1197 workers exposed to noise in petrochemical factories, textile factories, and parts manufacturing factories were selected as the study subjects. The noise reduction effect of hearing protectors worn by workers in daily use was tested using a hearing protector suitability testing system. The personal sound attenuation level (PAR) was compared among workers in three enterprises, Targeted intervention and repetitive testing were conducted for workers who did not meet the noise reduction effect required by the enterprise, and the changes in PAR of workers before and after the intervention were compared. The comparison of baseline PARs between two or more groups was performed using the Mann Whitney test, the comparison of baseline PARs with post intervention PARs was performed using the Wilcoxon signed rank sum test, and the comparison of qualitative data between two or more groups was performed using the Chi square test. Results: The median baseline PAR for all workers was 15 dB. Men, age<30 years old, education level at or above college level, working experience of 5 to 15 years, and those who used hearing protectors for 5 to 15 years had higher PARs, with statistically significant differences (P<0.05). The median difference in baseline PAR among workers from three enterprises was statistically significant (H=175.06, P<0.01). The median PAR of subjects who did not pass the baseline increased from 3 dB to 21 dB after intervention (Z=-27.92, P<0.01) . Conclusion: Some workers wearing hearing protectors do not meet the required PAR, and low PARs may be related to incorrect wearing methods and incorrect selection of hearing protectors. As a tool for testing, training, and assisting in selection, the hearing protector suitability testing system is of great significance for worker hearing protection.

Heart sound classification based on sub-band envelope and convolution neural network / 生物医学工程学杂志

Automatic classification of heart sounds plays an important role in the early diagnosis of congenital heart disease. A kind of heart sound classification algorithms based on sub-band envelope feature and convolution neural network was proposed in this paper, which did not need to segment the heart sounds according to cardiac cycle accurately. Firstly, the heart sound signal was divided into some frames. Then, the frame level heart sound signal was filtered with Gammatone filter bank to obtain the sub-band signals. Next, the sub-band envelope was extracted by Hilbert transform. After that, the sub-band envelope was stacked into a feature map. Finally, type Ⅰ and type Ⅱ convolution neural network were selected as classifier. The result shown that the sub-band envelope feature was better in type Ⅰ than type Ⅱ. The algorithm is tested with 1 000 heart sound samples. The test results show that the overall performance of the algorithm proposed in this paper is significantly improved compared with other similar algorithms, which provides a new method for automatic classification of congenital heart disease, and speeds up the process of automatic classification of heart sounds applied to the actual screening.

Investigation on skills of using dust mask in dust-exposed workers of civil metal ship manufacturing enterprises / 中国职业医学

OBJECTIVE: To analyze the skills of using dust mask in the dust-exposed workers in civil metal ship manufacturing enterprises. METHODS: A total of 123 dust-exposed workers in a civil metal ship manufacturing enterprise were selected as the research subjects using convenience sampling method. Dust Mask Using Situation and Maintenance Questionnaire was used to investigate the use of dust masks, and the tightness of using dust mask was measured by the tightness tester. RESULTS: The median, and the 0 th-100 th percentiles[M(P_0-P_(100))] of the dust mask use time in the workers was 3.0(1.0-3.0) months, and the M(P_0-P_(100)) of filter element use time was 1.0(0.5-2.0) workdays. The subjects did not disinfect the masks after use. Only 36.6%(45/123) of workers regularly cleaned dust masks during use. There was 62.6%(77/123) of workers who failed to correctly perform negative pressure air tightness check by themselves. A total of 112 workers carried out tightness test, and the pass rate of those who passed the tightness test for the first time was 62.5%(70/112). The median, and the 25 th and 75 th percentiles [M(P_(25), P_(75))] of fit factor(FF) in the 70 qualified workers was 835.0(503.0, 1 635.0). After retests, the overall tightness test pass rate was 66.1%(74/112), and the M(P_(25), P_(75)) of FF in the 74 qualified workers was 786.0(477.7, 1 532.2). The reasons for failure of tightness test were the mismatch of the mask and face size, wrong wearing methods and long beard. CONCLUSION: Some of the dust-exposed workers in the civil metal ship manufacturing enterprises did not use the dust mask correctly. The dust mask configuration and the use and maintenance training should be strengthened, and the tightness test should be carried out regularly to improve workers′ skills in using dust masks.

Research progress on verification methods on measuring noise attenuation value of hearing protective devices / 中国职业医学

At present, the methods for verifying the attenuation of hearing protective devices(HPDs) mainly include real-ear attenuation at threshold(REAT), microphone in real ear(MIRE), and acoustical test fixture(ATF). Among them, the REAT is the gold standard, but its testing requirements are strict and there is a physiological noise masking effect. The test results of MIRE need to be modified by transfer function of the open ear, which has the advantage of convenient operation without being affected by subjective feelings. The ATF method is mainly used to verify the shape and quality of customized HPDs since its artificial ear design cannot truly reflect the real-ear test situation. The HPD fit testing has been well developed and widely applied abroad, which has been proved to be able to accurately verify and effectively improve the attenuation of workers wearing HPDs. However, relevant research and applications have only been carried out in China in recent years. At present, the main problems in the verification of the protective effect of HPDs in China are as follows: firstly, the measurement is only limited in attenuation and fail to comprehensively consider the applicability and comfort of the HPDs; secondly, a-weighted sound pressure level is mostly used in noise monitoring in China, while the choice of HPDs is based on C-weighted-sound pressure level. The transition between these two has not been established. Future research should be devoted to solve the above problems and help the use of HPDs in preventing the hearing loss of noise-exposed workers.

Segmentation of heart sound signals based on duration hidden Markov model / 生物医学工程学杂志

Heart sound segmentation is a key step before heart sound classification. It refers to the processing of the acquired heart sound signal that separates the cardiac cycle into systolic and diastolic, etc. To solve the accuracy limitation of heart sound segmentation without relying on electrocardiogram, an algorithm based on the duration hidden Markov model (DHMM) was proposed. Firstly, the heart sound samples were positionally labeled. Then autocorrelation estimation method was used to estimate cardiac cycle duration, and Gaussian mixture distribution was used to model the duration of sample-state. Next, the hidden Markov model (HMM) was optimized in the training set and the DHMM was established. Finally, the Viterbi algorithm was used to track back the state of heart sounds to obtain S

Classification of heart sound signals in congenital heart disease based on convolutional neural network / 生物医学工程学杂志

Cardiac auscultation is the basic way for primary diagnosis and screening of congenital heart disease(CHD). A new classification algorithm of CHD based on convolution neural network was proposed for analysis and classification of CHD heart sounds in this work. The algorithm was based on the clinically collected diagnosed CHD heart sound signal. Firstly the heart sound signal preprocessing algorithm was used to extract and organize the Mel Cepstral Coefficient (MFSC) of the heart sound signal in the one-dimensional time domain and turn it into a two-dimensional feature sample. Secondly, 1 000 feature samples were used to train and optimize the convolutional neural network, and the training results with the accuracy of 0.896 and the loss value of 0.25 were obtained by using the Adam optimizer. Finally, 200 samples were tested with convolution neural network, and the results showed that the accuracy was up to 0.895, the sensitivity was 0.910, and the specificity was 0.880. Compared with other algorithms, the proposed algorithm has improved accuracy and specificity. It proves that the proposed method effectively improves the robustness and accuracy of heart sound classification and is expected to be applied to machine-assisted auscultation.

Case-control study on polymer polylactic acid absorbable medical film for preventing acromion adhesion after arthroscopic rotator cuff repair / 中国骨伤

<p><b>OBJECTIVE</b>To study effect of shoulder joint function after rotator cuff repair of polylactic acid absorbable membrane.</p><p><b>METHODS</b>From September 2015 to December 2016, 50 patients diagnosed with rotator cuff tear were selected and divided into treatment group and control group. There were 25 patients in control group, including 12 males and 13 females, with an average age of (48.7±3.5) years old, who received simple arthroscopic rotator cuff repair. There were 25 patients in treatment group, including 11 males and 14 females, with an average age of(49.2±4.1) years old, who performed arthroscopic rotator cuff repair with implanting polylactic acid absorbable membraneon shoulder of rotator cuff. Preoperative and postoperative VAS score, ASES score and UCLA score were recorded and compared between two groups.</p><p><b>RESULTS</b>At 6 months after operation, preoperative VAS score in control group was 5.48±1.12, and decreased as 1.28±0.84 after operation; ASES score before operation was 52.24±4.64, and improved to 86.92±3.20 after operation;preoperative UCLA score improved from 14.36±1.89 before operation to 30.72±1.28 after operation. In treatment group, VAS score decreased from 5.36±1.32 before operation to 1.40±0.71 after operation;preoperative ASES score was 51.04±4.09, and improved to 88.96±2.79 after operation; UCLA score improved from 15.12±1.81 before operation to 32.12±1.33 after operation. There was no significant difference in VAS score between two groups, and ASES score, UCLA score in treatment group was obviously better than control group.</p><p><b>CONCLUSIONS</b>Application of polylactic acid absorbable medical membrane could obviously improve shoulder function, and effectively prevent acromion adhesion after arthroscopic rotator cuff repair.</p>

Treatment of acromion base fractures with double plates internal fixation / 中国骨伤

<p><b>OBJECTIVE</b>To study clinical effects of double plates fixation for the treatment of acromion base fracutres.</p><p><b>METHODS</b>From January 2010 to May 2012, 7 patients with acromion base fractures were treated with double plates ORIF surgical treatment. There were 5 males and 2 females, with an average age of 36.3 years old (ranged, 24 to 62 years old). All fractures were acuted and closed injuries. The duration from injury to surgery was 4.6 days (ranged, 2 to 10 days). Hardegger functional criterion, Visual Analogue Scale (VAS) and complications of the patients were documented analysis.</p><p><b>RESULTS</b>All the patients were followed up,and the duration ranged from 4 to 13 months (averaged 8.9 months). The healing duration of fractures ranged from 8 to 14 weeks without any infection, shoulder instability, subacromial impingement syndrome, nonunion and failure of internal fixation. At the latest follow-up, the VAS ranged from 0 to 5. According to Hardegger criterion, 2 patients got an excellent result, 4 good and 1 poor.</p><p><b>CONCLUSION</b>Double plates ORIF plays a positive role in the treatment of acromion base fractures, which reduces complications and maximally restore the function of shoulder.</p>

Raman spectroscopic analysis of Paeoniae Radix Alba decoction based on Raman technology / 中国中药杂志

<p><b>OBJECTIVE</b>To test and analyze chemical composition of Paeoniae Radix Alba decoction at molecular level.</p><p><b>METHOD</b>Raman spectra of decoctions prepared from seven batches of Paeoniae Radix Alba pieces, five batches of Paeoniae Radix Alba medicinal material and five batches of Paeoniae Radix Rubra pieces were measured respectively, and the characteristic Raman bands were tentatively assigned. Raman spectra of decoctions were compared and analysed between Paeoniae Radix Alba pieces and Paeoniae Radix Alba medicinal material, Paeoniae Radix Alba pieces and Paeoniae Radix Rubra pieces.</p><p><b>RESULT</b>Nine Raman bands (637, 783, 847, 981, 1 091, 1 128, 1 336, 1 458 and 1 636 cm(-1)) were observed in the Paeoniae Radix Alba pieces decoction. Compared with the decoction of Paeoniae Radix Alba pieces, the Raman bands of 783, 981, 1 128, 1 336 and 1 458 cm(-1) were also exists in Paeoniae Radix Alba medicinal material decoction, meanwhile, the Raman bands of 633 cm(-1) and 1 633 cm(-1) occurs slight frequency shift, however, the bands of 716, 737, 835, 916, 1 072, 1 271 and 1 600 cm(-1) were disappear. In addition, the Raman spectra are quite different between the decoctions of Paeoniae Radix Alba pieces and Paeoniae Radix Rubra pieces.</p><p><b>CONCLUSION</b>The results showed that Raman spectroscopy might provide a novel method for the fast component detection of the Radix Paeoniae Alba decoction or other traditional Chinese medicine.</p>

Yoga is found hazardous to the meniscus for Chinese women / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>Yoga is becoming more and more popular in the female society while the concomitant sports injury is seldom mentioned. Many clinicians have noted that yoga may result in knee problems, which though requires more researches to corroborate. This investigation was conducted to ascertain the relationship between yoga and meniscus injury as well as the extent of impairment according to variant yoga practice periods.</p><p><b>METHODS</b>Totally 819 women aged 20-49 years who practiced yoga or other popular sports including badminton, jogging, climbing hills, etc for at least one hour per day were selected to participate in this research. These subjects were required to complete a questionnaire and receive relevant physical examination. Magnetic resonance (MR) scan of the knee was recommended for the suspicious subjects for ultimate diagnosis. The subject with abnormal meniscus MR signals was defined as a case and matched with two controls in terms of age and body mass index (BMI). Altogether there were 273 cases and 546 controls. The nested case-control model was adopted to assess the risk of meniscus injury between variant exposures in practicing yoga and several other popular sports. Moreover, the 181 yoga subjects were subdivided into three groups according to different exercise durations, followed by further analysis with the variables of age, BMI and Lysholm score.</p><p><b>RESULTS</b>Yoga was found associated with a higher risk (P equal to 0.008, OR equal to 1.621) of meniscus injury compared with badminton, jogging and climbing hills. The three yoga subgroups showed statistical difference between each other in terms of Lysholm score (P equal to 0.027) and BMI (P equal to 0.003). The subjects with longer-term yoga practice had lighter weight but lower Lysholm scores.</p><p><b>CONCLUSIONS</b>Yoga perhaps exerts destructive impact on the meniscus for Chinese women, yet it needs further verifications. Furthermore, the female yoga players with longer exercise duration are more susceptible to meniscus injury though they can become leaner.</p>

Clinical analysis of preoperative deep venous thrombosis (DVT) complicated lower extremity close fractures / 中国骨伤

<p><b>OBJECTIVE</b>To study the instance of deep venous thrombosis(DVT) complicated by preoperative lower extremity close fracture.</p><p><b>METHODS</b>Retrospectively analyzed the clinical data of 54 patients with DVT (through color Doppler to final diagnosis) complicated by preoperative lower extremity close fracture from March 2008 to February 2009, and explored the concomitant reason of DVT. There were 23 males and 31 females with age for 23-95 years old.</p><p><b>RESULTS</b>DVT including thrombus of ilio-venae external, thrombus of femoral vein, thrombus of popliteal vein, thrombus of posterior tibial veins and thrombus of soleus venae. The instance of DVT complicated by preoperative lower extremity close fracture: (1) The age of 23 cases (42.59%) more than 70 years. (2) 11 cases (20.37%) combined with syndrome, 2 cases had hypertension, 3 cases had hypertension and diabetes, 2 cases hypertension and cerbral infarction, 4 cases had hypertension, diabetes and coronary heart disease. (3) 10 cases (18.51%) were multi-fractures. (4) 28 cases (51.85%) occurred DVT at 7-14 days after lower extremity close fracture.</p><p><b>CONCLUSION</b>Advanced age, complicating hypertension, diabetes, coronary heart disease, cerbral infarction, multi-fractures may be lead to DVT. Multitudinous DVT occurred at 7-14 days after fracture, as early as possible operation has important significance on prevention DVT to decrease risk of pulmonary embolism.</p>

p38/ERK signal pathways regulating the expression of type I collagen and activity of MMP-2 in TGF-beta1-stimulated HLF-02 cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the role of TGF-beta(1)/MAPK signaling pathways in the expression of type I collagen and activity of MMP-2, 9 in human lung fibroblasts.</p><p><b>METHODS</b>Human lung fibroblasts cell line (HLF-02) was cultured and and then stimulated with 10 ng/ml TGF-beta(1) for different time; SB203580 or PD98059 was added into culture medium to block p38 or ERK kinase pathway before incubated with TGF-beta(1); the expression of type I collagen was detected by Western blotting and RT-PCR; zymogram analysis was used to analyze the activity of MMP-2 and MMP-9.</p><p><b>RESULTS</b>(1) In the process of stimulation by TGF-beta(1), the type I collagen mRNA level of 24 h, 48 h and 72 h group was: 1.33 +/- 0.07, 2.46 +/- 0.09 and 2.39 +/- 0.08 respectively; and the type I collagen protein level of 24 h, 48 h and 72 h group was: 114.89 +/- 8.95, 208.16 +/- 6.75 and 211.46 +/- 8.05 respectively; and the activity of MMP-2 of 24 h, 48 h and 72 h group was: 190.33 +/- 5.86, 214.33 +/- 8.39 and 212.67 +/- 11.59 respectively. (2) SB203580 significantly inhibited the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 51%, 24% and 20%); (3) PD98059 also significantly attenuated the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 42%, 13% and 16%).</p><p><b>CONCLUSION</b>TGF-beta(1) is capable of inducing the expression of type I collagen mRNA and protein and up-regulating MMP-2 activity in HLF-02 cells. p38 and ERK kinase signaling pathways play important role in regulation and control for this process.</p>