OBJECTIVETo study neck and shoulder work-related muscle fatigue of female sewing machine operators.

METHODS18 health female sewing machine operators without musculoskeletal disorders work in Beijing garment industry factory as volunteers in participate of this study. The maximal voluntary contraction (MVC) and 20% MVC of bilateral upper trapezium and cervical erectors spinae was tested before sewing operations, then the whole 20 time windows (1 time window = 10 min) sewing machine operations was monitored and the surface electromyography (sEMG) signals simultaneously was recorded after monitoring the 20%MVC was tested. Use amplitude analysis method to reduction recorded EMG signals.

RESULTSDuring work, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezium (LUT) and right upper trapezium (RUT) respectively was 6.78 ± 1.05, 6.94 ± 1.12, 5.68 ± 2.56 and 6.47 ± 3.22, work load of right is higher than the left; static load analysis indicated the value of RMS(20%MVC) before work was higher than that value after work, the increase of right CES and UT RMS(20%MVC) was more; the largest 20%MVE of bilateral CES occurred at 20th time window, and that of bilateral UT happened at 16th.

CONCLUSIONSThe work load of female sewing machine operators is sustained "static" load, and work load of right neck-shoulder is higher than left, right neck-shoulder muscle is more fatigable and much serious once fatigued.

Adult ; Electromyography ; Female ; Humans ; Muscle Fatigue ; physiology ; Posture ; Shoulder ; physiology ; Textile Industry ; Work ; Young Adult

OBJECTIVETo study the metabolic difference of body influenced by active stress and passive stress under special events.

METHODSTo detect serum multiple biochemistry index of 57 earthquake rescue medical team and 13 victims of a natural calamity in Wenchuan earthquake by using Hitachi 7600 automatic analyzer.

RESULTSStress affected biochemistry index deeply. To compared with rescue medical team, the serum ADA, ALP and TG of victims increased obviously and TP, ALB, MAO, Cr, UA, K, Na, Cl, Ca, ApoA1 and HDL decreased obviously.

CONCLUSIONMany biochemistry index have been changed under stress and it relate with stress extent. The human body function status was better in active stress than in passive stress.

Blood Chemical Analysis ; China ; Disasters ; Earthquakes ; Humans ; Metabolism ; physiology ; Rescue Work ; Stress, Physiological ; physiology

PURPOSE: The present study was carried out to determine day-to-day differences in cortisol levels and the molar cortisol-to-dehydroepiandrosterone (DHEA) ratio (molar C/D ratio) in working subjects. MATERIALS AND METHODS: The cortisol and DHEA levels were measured from saliva samples collected 30 minutes after awakening for 7 consecutive days in full-time working subjects that worked Monday through Saturday. To determine the day-to-day differences within subjects, the collected data was analyzed using variance (ANOVA) for a randomized complete block design (RCBD). RESULTS: The cortisol levels from samples collected 30 minutes after awakening on workdays were similar to each other, but were significantly different from the cortisol levels on Sunday. The DHEA levels were not significantly different between the days of week. The DHEA levels on Monday and Tuesday were relatively lower than the levels on the other weekdays. The DHEA levels on Thursday and Friday were relatively higher than the other days. The molar C/D ratios on Sunday were significantly lower than those on workdays. The molar C/D ratios on Monday and Tuesday were significantly higher than those on Wednesday or other workdays. CONCLUSION: The cortisol levels and the molar C/D ratios demonstrate differences in adrenocortical activities between workdays and non-workdays, but the molar C/D ratio additionally represents differences in adrenocortical status between the first two workdays and other workdays. Thus, it is possible that the day-to-day differences in the cortisol levels and the molar C/D ratio represent the adrenal response to upcoming work-related stress.
Adult ; Analysis of Variance ; Dehydroepiandrosterone/*metabolism ; Female ; Humans ; Hydrocortisone/*metabolism ; Male ; Middle Aged ; Saliva/chemistry ; Work/*physiology

In order to improve synchrony between a ventilator and its patient, a new method for triggering a ventilator based on diaphragmatic electromyogram (EMG) is introduced. The methods to extract and process diaphragmatic EMG signals are studied. It has been shown that the characteristic parameters of a respiration activity, such as inspiratory beginning point, expiratory beginning point and respiration period, can be detected from diaphragmatic EMG envelop instead of traditional flux curve. A new parameter, designated as diaphragmatic "Intensity of EMG" for short "IEMG", is defined. Repeat respiration tests have disclosed that there is relatively high correlation between the diaphragmatic IEMG curve and its corresponding cubage curve. These results primarily demonstrate that the new synchronization method may be feasible.
Diaphragm ; physiology ; Electromyography ; Humans ; Positive-Pressure Respiration ; methods ; Respiration ; Respiration, Artificial ; methods ; Respiratory Insufficiency ; therapy ; Respiratory Muscles ; physiology ; Work of Breathing ; physiology

OBJECTIVETo determine the anthropometric parameters and the isometric muscle strength in a working population sample in China, and to investigate the relationship between muscle strength and individual attributes, such as age, gender, height and weight.

METHODSThe study population consisted of 146 male and 47 female people including workers, administrators and college students. Four types of muscle strength, i.e., handgrip, arm lift, shoulder lift, and torso pull, were measured.

RESULTSLeft handgrip, right handgrip, arm lift, shoulder lift and torso pull of male workers were (42.07 +/- 7.20), (43.92 +/- 7.14), (26.79 +/- 4.64), (33.79 +/- 6.88), (88.56 +/- 17.98) kg, respectively while those of female workers were (21.29 +/- 5.09), (23.26 +/- 5.47), (13.29 +/- 3.37), (18.52 +/- 4.01), (41.06 +/- 12.04) kg, respectively. The female's strength was about 50% lower than the male's. The strength in the 40 approximately years old group was higher than that in other age groups. There were significant positive correlation between the gender and the isometric strength as well as between the body weight and the isometric strength. If the body weight served as the corrected parameter, there was no significant difference in the handgrip among the groups (P < 0.05), but the torso pull of male workers > college students > administrators. All relative muscle strengths except the torso pull were similar for all age groups.

CONCLUSIONThe body weight as the independent variable can be used for establishing the predictive equation of the muscle strength. Calculation of the relative muscle strength can relieve the interference of the body weight for the muscle strength.

Adolescent ; Adult ; Anthropometry ; Female ; Hand Strength ; physiology ; Humans ; Male ; Middle Aged ; Muscle Contraction ; physiology ; Muscle Strength ; physiology ; Muscle Strength Dynamometer ; Pilot Projects ; Transactional Analysis ; Work Capacity Evaluation

OBJECTIVETo investigate the effect of non-invasive positive pressure ventilation (NIPPV) on the work of breathing (WOB) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD).

METHODSEleven patients with acute exacerbation of COPD received pressure support ventilation (PSV) at different levels during NIPPV. The changes of inspiratory muscle effort and breathing pattern of the patients were observed.

RESULTSThe average minute ventilation (VE, P<0.01) and tidal volume (VT, P<0.05) of the patients were significantly higher during routine PSV and high pressure support (H-PS) than those during spontaneous breathing (SB), and the breathing pattern of the patients did not undergo significant changes during high positive end expiratory pressure (H-PEEP). The WOB of the inspiratory muscles was reduced significantly during PSV as compared with that measured in SB (P<0.01), while the WOB of exspiratory muscle increased significantly (P<0.01).

CONCLUSIONNIPPV can relieve the load of the inspiratory muscles in patients with acute exacerbation of COPD, and the WOB of the inspiratory muscles can be reduced by PSV, H-PEEP and H-PS (by 75%, 71% and 76%, respectively), but higher PSV during NIPPV can cause higher WOB of the exspiratory muscles.

Aged ; Exhalation ; physiology ; Humans ; Inhalation ; physiology ; Male ; Middle Aged ; Pressure ; Pulmonary Disease, Chronic Obstructive ; pathology ; physiopathology ; therapy ; Pulmonary Ventilation ; Work of Breathing ; physiology

PURPOSE: The aim of this study was to identify influencing factors for sleep quality among shift-working nurses based on a three-factor scoring model that included sleep efficacy, sleep quality and daily dysfunction. METHODS: A cross-sectional survey of 513 nurses in a hospital in Shanghai, China, was conducted using a self-reported questionnaire. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI). Data were analyzed based on the three-factor PSQI model: Factor 1, sleep efficacy; Factor 2, sleep quality; Factor 3, daily disturbances. RESULTS: After adjusting for age, marital status, and having children, multivariate logistic regression analysis showed that participants who had previous shift work experience which was at least 6 months ago, or were currently performing shift work were significantly more likely to have poor sleep quality (PSQI > 5) than those who had never done shift work (adjusted odds ratios of 3.943 and 3.975, respectively, both p < .001). Mean scores of the three individual factors increased significantly among nurses currently performing shift work compared with those who had never done shift work (Factor 1, β = 0.61, p < .001; Factor 2, β = 1.86, p < .001; Factor 3, β = 0.45, p = .002). Mean scores of Factor 2 and Factor 3 increased significantly among nurses with previous shift work experience compared with those who had never done shift work (Factor 2, β = 1.15, p = .003; Factor 3, β = 0.52, p = .005). CONCLUSIONS: Performing current shift work and performing shift work previously were significantly associated with poor sleep quality. An appropriate arrangement and intervention strategies are needed in Chinese hospitals in order to improve sleep quality among shift-working nurses.
Adult ; China/epidemiology ; Cross-Sectional Studies ; Female ; Humans ; Male ; Nurses/*statistics & numerical data ; Risk Factors ; Sleep/*physiology ; Sleep Deprivation/*epidemiology ; Work Schedule Tolerance/*physiology

Blood Platelets/*drug effects ; Blood Platelets/enzymology ; Cholinesterase Inhibitors/*adverse effects ; Models, Animal ; Movement/*physiology ; Platelet Aggregation/*drug effects ; Pyridostigmine Bromide/*adverse effects ; Work/*physiology

OBJECTIVE: The purpose of this study is to evaluate the airway dynamics of the upper airway as depicted on cine MRI in children with tracheotomy tubes during two states of airflow through the upper airway. MATERIALS AND METHODS: Sagittal fast gradient echo cine MR images of the supra-glottic airway were obtained with a 1.5T MRI scanner on seven children with tracheotomy tubes. Two sets of images were obtained with either the tubes capped or uncapped. The findings of the cine MRI were retrospectively reviewed. Volume segmentation of the cine images to compare the airway volume change over time (mean volume, standard deviation, normalized range, and coefficient of variance) was performed for the capped and uncapped tubes in both the nasopharynx and hypopharynx (Signed Rank Test). RESULTS: Graphical representation of the airway volume over time demonstrates a qualitative increased fluctuation in patients with the tracheotomy tube capped as compared to uncapped in both the nasopharyngeal and hypopharyngeal regions of interest. In the nasopharynx, the mean airway volume (capped 2.72 mL, uncapped 2.09 mL, p = 0.0313), the airway volume standard deviation (capped 0.42 mL, uncapped 0.20 mL, p = 0.0156), and the airway volume range (capped 2.10 mL, uncapped 1.09 mL, p = 0.0156) were significantly larger in the capped group of patients. In the hypopharynx, the airway volume standard deviation (capped 1.54 mL, uncapped 0.67 mL, p = 0.0156), and the airway volume range (capped 6.44 mL, uncapped 2.93 mL, p = 0.0156) were significantly larger in the capped tubes. The coefficient of variance (capped 0.37, uncapped 0.26, p = 0.0469) and the normalized range (capped 1.52, uncapped 1.09, p = 0.0313) were significantly larger in the capped tubes. CONCLUSION: There is a statistically significant change in airway dynamics in children with tracheotomy tubes when breathing via the airway as compared to breathing via the tracheotomy tube.
Adolescent ; Child ; Child, Preschool ; Female ; Humans ; Hypopharynx/anatomy & histology/*physiology ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging, Cine/*methods ; Male ; Nasopharynx/anatomy & histology/*physiology ; Retrospective Studies ; Time Factors ; Tracheostomy/*instrumentation ; Work of Breathing/*physiology

OBJECTIVEIn this study, we aimed at exploring the association between work-related musculoskeletal disorders (WMSDs) and work organization based on a case-control study.

METHODSA total of 1938 workers who claimed to suffer from WMSDs were selected from Beijing, Henan, Hubei, and the Guangdong province. The control group consisted of 2009 workers employed in similar industries without severe disease or musculoskeletal discomforts. We used a modified version of the questionnaire developed by the NMQ and the DMQ to investigate individual and work-related factors.

RESULTSA total of 13 variables (P<0.1) were selected by the chi-square test and finally, 7 variables entered into the equation, with 6 variables reaching statistical significance (P<0.05). The odds ratios (OR) of 'work changing with season' and 'sufficient rest time' did not reach 1 (0.749 and 0.441, respectively). In addition, 'sufficient rest time' seemed to be the stronger protective factor according to its higher standardized coefficient. And 'repetitive work every minute', 'constantly repetitive work' (every day), 'shortage of site personnel', and 'often switching shifts with others' seemed to be the risk factors.

CONCLUSIONWork organization may have comprehensive effects on the occurrence of WMSDs. This pattern of associations suggests that further investigation into the mechanism of how work organization affects the prevalence of WMSDs is required.

Adult ; Case-Control Studies ; Chi-Square Distribution ; China ; epidemiology ; Cross-Sectional Studies ; Cumulative Trauma Disorders ; epidemiology ; etiology ; Demography ; Ergonomics ; standards ; Female ; Humans ; Logistic Models ; Male ; Musculoskeletal Diseases ; epidemiology ; etiology ; Occupational Diseases ; epidemiology ; etiology ; Personnel Staffing and Scheduling ; organization & administration ; Prevalence ; Risk Factors ; Seasons ; Surveys and Questionnaires ; Work Schedule Tolerance ; physiology ; Workplace ; organization & administration ; Young Adult