ABSTRACT
Objective @#To investigate the status of occupational stress and analyze its influencing factors among frontline employees working in a chemical fiber manufacturing enterprise, so as to provide insights into the development of occupational stress interventions. @*Methods @#The frontline employees working in a chemical fiber manufacturing enterprise were selected as the study subjects using a cluster sampling method in October 2018. The status of occupational stress was investigated using the Chinese version of the effort-reward imbalance ( ERI ) questionnaire. The influencing factors for occupational stress were identified using a multivariable logistic regression model. @*Results @#A total of 1 780 questionnaires were sent out, and 1 115 valid ones ( 62.64% ) were recovered. Among the 1 115 respondents, there were 427 men ( 38.30% ) and 688 women ( 61.70% ), and 71.22% were at ages of 21 to 39 years. There were 561 respondents with < 1 year of service ( 50.31% ), and the longest length of service was 11 years. In addition, there were 1 069 respondents ( 95.87% ) exposed to high noise, and 346 respondents ( 31.03% ) were diagnosed at a high occupational-stress state and 769 ( 68.97% ) at a low state. Multivariable logistic regression analysis identified 5 years or longer of service ( OR=1.540, 95%CI: 1.057-2.245 ) and exposure to high noise ( OR=1.917, 95%CI: 1.004-3.659 ) as risk factors for occupational stress among frontline employees in the chemical fiber manufacturing enterprise. @*Conclusions @#There are 31.03% of frontline employees at a high occupational-stress state in the chemical fiber manufacturing enterprise, and a high occupational-stress state is associated with exposure to high noise and 5 years or longer of service.
ABSTRACT
This study employed a Bac-to-Bac/Bombyx mori bioreactor to mass-produce immunogenic urease subunit B (UreB) from Helicobacter pylori. The signal peptide bombyxin from B. mori was used to promote secretory expression to improve expression levels and was designed and integrated into the UreB gene to generate the Bacmid/BmNPV/(signal peptide)-UreB baculovirus expression system. To determine whether the bombyxin signal peptide resulted in secretory expression of recombinant UreB (rUreB) and to determine the secretory efficiency, we tested the secretory expression level of rUreB in Bm5 cells using ELISA. To further investigate whether secretory expression affected cell viability, cells were evaluated using 0.4% trypan blue staining, and Bacmid/BmNPV/UreB without the signal peptide served as a control. The above recombinant bacmid constructs were injected to silkworm larvae, and the secretory expression level of rUreB was detected using SDS-PAGE and semi-quantitative western blot analysis. The results indicated that the bombyxin signal peptide directed the secretory expression of rUreB and that this expression improved the viability of Bm5 cells. Moreover, the results showed that the expression level of rUreB was 1.5 times higher with the Bacmid/BmNPV constructs containing the bombyxin signal sequence than those without the signal sequence. These results demonstrate that secretory expression can enhance rUreB expression levels and is likely to aid in the large-scale expression and yield of rUreB in silkworm larvae.
ABSTRACT
Researches have shown that melatonin is neuroprotectant in ischemia/reperfusion-mediated injury.Although melatonin is known as an effective antioxidant,the mechanism of the protection cannot be explained merely by antioxidation.This study was devoted to explore other existing mechanisms by investigating whether melatonin protects ischemia/reperfusion-injured neurons through elevating autophagy,since autophagy has been frequently suggested to play a crucial role in neuron survival.To find it out,an ischemia/reperfusion model in N2a cells was established for examinations.The results showed that autophagy was significantly enhanced in N2a cells treated with melatonin at reper-fusion onset following ischemia and greatly promoted cell survival,while autophagy blockage by 3-MA led to the shortened N2a cell survival as assessed by MTT,transmission electron microscopy,and laser confocal scanning microscopy.Besides,the protein levels of LC311 and Beclinl were remarkably increased in ischemia/reperfusion-injured N2a in the presence of melatonin,whereas the expression of p-PKB,key kinase in PI3K/PKB signaling pathway,showed a decrease when compared with untreated subjects as accessed by immunoblotting.Taken together these data suggest that autophagy is possibly one of the mechanisms underlying neuroprotection of melatonin.