Relationship between acute stress and sleep disorder in grass-root military personnel:Mediating effect of social support

Background: To explore the relationship between acute stress, social support and sleep disorder in grass-root military personnel, and construct the relational model through structural equation modeling. Methods: A total of 2,411 grass-root military personnel were randomly selected by cluster sampling, and administered the Chinese Military Personnel Sleep Disorder Scale, Military Acute Stress Scale and Social Support Rating Scale.Results: The total score of acute stress scale was positively correlated with the total score and factor scores of sleep disorder scale(r=0.209~0.465, P【0.01); The total score of social support scale was positively correlated with the total score of acute stress scale and the total score and factor scores of sleep disorder scale(r=0.356~0.537, P【0.01). The analysis of mediating effects showed that lack of social support partially mediated between acute stress and the factors of sleep disorder. The analysis of structural equation model showed that acute stress not only had a direct effect on sleep disorder(the path coefficient was 0.29, P=0.000), but also on lack of social support(the path coefficient was 0.39, P=0.000); lack of social support had a direct effect on sleep disorder(the path coefficient was 0.48, P=0.000).Conclusions: Acute stress and lack of social support are two significant factors of sleep disorder in grass-root military personnel. Well-established social support could alleviate sleep disorder induced by acute stress. Lack of social support was a partial mediator between acute stress and sleep disorder.

Scene-trait coping style of military rescuers in Wenchuan earthquake

Objective This study aimed to explore the scene-trait coping style of military rescuers in Wenchuan earthquake in an effort to provide scientific evidences for mental intervention program for Chinese military personnel.Methods By cluster sampling,a total of 151 military rescuers and 331 control servicemen were administered the military personnel scene-trait coping style scale(MPSTCSS).Results All active coping factor scores,and passive coping factor scores of affection,health and economy in the rescuer group were significantly higher than those in control group(P<0.05).The 21-above age subgroup,the3-year plus service subgroup,and the officer subgroup had significantly higher active coping factor scores on military tasks,military experience and personal development than those of the 21-below age subgroup,3-year minus service subgroup and the soldier subgroup,respectively(P<0.05 or P<0.01).Conclusion The earthquake relief servicemen can cope with stressful situations better than control group by taking active coping style.The officers,servicemen older than 21 years,and servicemen with more service duration than3 years could usually take active coping style.

Microstructure and microhardness of a novel TiZrAlV alloy by laser gas nitriding at different laser powers

The Ti-20Zr-6.5Al-4V(T20Z,wt%)alloy surface was treated by the process of laser surface nitriding.The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120 to 240 W.All laser-treated T20Z samples show two regions with distinctly different microstructural features,as compared with the untreated substrate:dense TiN dendrites and(α+β)-Ti(remelting zone,RMZ),nanoscaleαlaths doped with part of p phase(heat-affected zone,HAZ).The formation of TiN dendrites can be analyzed by a series of complex reactions during the process of melting and solidification.The increase in laser power results in the increase in content of TiN dendrite which is mainly due to the increase in energy input.In HAZ,the self-quenching effect leads to the formation of nanoscale a laths and the residue ofβphase.Microhardness profile of different regions was measured from the surface to the interior,and the highest microhardness was obtained(~HV 916.8)in the RMZ,as the laser power was set to 240 W.In the present study,we explained various microstructural characteristics induced by laser surface nitriding treatment.