[Effects of occupational stress and related factors on depression symptoms in train drivers]

OBJECTIVE

To explore the influence of occupational stress and related factors on depression symptoms in train drives.

METHODS

In March 2012, by using cluster sampling method, a cross-sectional epidemiological study was conducted in 1 402 train drivers in China. Questionnaires was investigation was conducted by face to face interview. Sample with missing variables on demographic characteristics questionnaire with missed survey variables, and occupational stress related factors and with over 3 item missing in depression symptoms self-rating scale were exclued. Depression symptoms were measured by Center for Epidemiological Survey Depression Scale. The occupational stress related actors were measured by the revised effort-reward imbalance (ERI) model questionnaires and occupational stress measurement scale. Chi-square test was carried out to analyze the differences of the incidence of depressive symptoms among different general characteristics groups, and multivariate logistic regression analysis was conducted to analyze the influence of occupational stress and related factors on depression symptoms in train drivers.

RESULTS

The study showed that the average age of 1 402 subjects was (34.95±9.20) years, the length of service were (13.28±9.78) years, the score of depressive symptoms was (24.14±5.98) scores. 902 subjects (64.3%,902/1 402) were classified as people with depressive symptoms, the incidence of depressive symptoms in EMU or high-speed train drivers were the highest (68.0%,51/75); Incidence of depressive symptoms showed that were statistically significant differences in two groups of technical secondary school and college, and incidence of depressive symptoms in the junior college and above group (68.1%,352/517) was higher than that in the senior high school and below group (62.1%, 550/885) (χ(2)=5.02, P=0.025). The results of the multiple logistic regression analysis revealed that high levels of education (OR=1.63, 95%CI: 1.12-2.19), role conflict (OR=1.65, 95% CI: 1.21-2.24), role ambiguity (OR=1.99, 95% CI: 1.45-2.73), negative emotion(OR=2.87, 95%CI: 2.15-3.82), daily tension(OR=2.86, 95%CI: 2.11-3.86), poor colleagues and family support (OR=1.55, 95% CI: 1.11-2.16 and OR=1.75, 95% CI: 1.27-2.41) were risk factors of depressive symptoms, but positive emotion (OR=0.72, 95% CI: 0.53-0.96), self-esteem (OR=0.22, 95% CI: 0.16-0.30), and job itself satisfaction (OR=0.48, 95%CI: 0.35-0.65) were protective factors of depressive symptoms in train drivers.

CONCLUSION

Train drivers, in particular EMU or high-speed train drivers who were prone to depressive symptoms. To arrange reasonably job roles and tasks, increase support from superiors, colleagues, and family, bring up healthy and coordinated personality, keep a good mood, promote job satisfaction, reduce the daily tension have positive effects on reducing the occurrence of depressive symptoms for train drivers.

Microwave-assisted extraction and a new determination method for total steroid saponins from Dioscorea zingiberensis C.H. Wright

An efficient microwave-assisted extraction (MAE) technique was applied to isolate total steroid saponins from Dioscorea zingiberensis C.H. Wright (DZW). The optimal extracting conditions were established as 75% ethanol as solvent, ratio of solid/liquid 1:20 (g/ml), temperature 75 °C, irradiation power 600 W and three extraction cycles of 6 min each. Scanning electron microscopy (SEM) images of DZW processed by four different extractions provided visual evidence of the disruption effect on DZW. Diosgenin was quantified by HPLC and examined further by LC-ESI/MS after acid hydrolysis. Total steroid saponins were calculated using diosgenin from total steroid saponins. The MAE procedure was optimized, validated and compared with other conventional extraction processes. This report provides a convenient technology for the extraction and quantification of total saponins of DZW combining MAE with HPLC and LC-ESI/MS for the first time.

Unparalleled Lithium and Sodium Superionic Conduction in Solid Electrolytes with Large Monovalent Cage-like Anions

Solid electrolytes with sufficiently high conductivities and stabilities are the elusive answer to the inherent shortcomings of organic liquid electrolytes prevalent in today's rechargeable batteries. We recently revealed a novel fast-ion-conducting sodium salt, Na₂B₁₂H₁₂, which contains large, icosahedral, divalent B₁₂H₁₂^2- anions that enable impressive superionic conductivity, albeit only above its 529 K phase transition. Its lithium congener, Li₂B₁₂H₁₂, possesses an even more technologically prohibitive transition temperature above 600 K. Here we show that the chemically related LiCB₁₁H₁₂ and NaCB₁₁H₁₂ salts, which contain icosahedral, monovalent CB₁₁H₁₂^- anions, both exhibit much lower transition temperatures near 400 K and 380 K, respectively, and truly stellar ionic conductivities (> 0.1 S cm^-1) unmatched by any other known polycrystalline materials at these temperatures. With proper modifications, we are confident that room-temperature-stabilized superionic salts incorporating such large polyhedral anion building blocks are attainable, thus enhancing their future prospects as practical electrolyte materials in next-generation, all-solid-state batteries.

Structure and polymorphism of novel X-chromosome short tandem repeat loci in a Chinese Han population

Recently, 5 novel X-chromosome short tandem repeat (X-STR) loci with high degrees of polymorphism were examined. In this study, we investigated the genetic distribution of these loci in a Chinese Han population. The 5 X-STR loci were successfully examined by polyacrylamide gel electrophoresis in a total of 200 unrelated Shaanxi Han individuals (100 males and 100 females). Hardy-Weinberg equilibrium tests revealed no significant deviation from expected values (P > 0.05) for all 5 X-STR loci in the Shaanxi Han population.The loci were named DXS-p11.3, DXS-q12, DXS-q13.3, DXS-q22.1, and DXS-q25 and were found to contain 6, 8, 7, 7, and 5 alleles, respectively. In addition, 17, 21, 18, 19, and 11 genotypes, respectively, were detected in the female samples. The heterozygosities of the 5 X-STR loci were 0.75, 0.74, 0.74, 0.72, and 0.56, respectively. The polymorphic information contents of the 5 X-STR loci were 0.70, 0.69, 0.69, 0.68, and 0.51, respectively. The individual discrimination values of the 5 X-STR loci were 0.88, 0.86, 0.88, 0.87, and 0.74, respectively. Five new X-chromosome STR loci with high degrees of polymorphism were observed in our lab. The results of this study are important for forensic individual identification, paternity identification, and population genetics research.

Precision Measurement of the Helium Flux in Primary Cosmic Rays of Rigidities 1.9 GV to 3 TV with the Alpha Magnetic Spectrometer on the International Space Station

Knowledge of the precise rigidity dependence of the helium flux is important in understanding the origin, acceleration, and propagation of cosmic rays. A precise measurement of the helium flux in primary cosmic rays with rigidity (momentum/charge) from 1.9 GV to 3 TV based on 50 million events is presented and compared to the proton flux. The detailed variation with rigidity of the helium flux spectral index is presented for the first time. The spectral index progressively hardens at rigidities larger than 100 GV. The rigidity dependence of the helium flux spectral index is similar to that of the proton spectral index though the magnitudes are different. Remarkably, the spectral index of the proton to helium flux ratio increases with rigidity up to 45 GV and then becomes constant; the flux ratio above 45 GV is well described by a single power law.

Buckled Tin Oxide Nanobelt Webs as Highly Stretchable and Transparent Photosensors

Stretchable and transparent inorganic semiconductors play a key role for the next generation of wearable optoelectronics. Achieving stretchability in intrinsically rigid inorganic materials is far more challenging than in polymers and metals. Here, we present a low-cost and scalable strategy to engineer inorganic semiconductors into a buckling open-mesh configuration, by which extraordinary stretchability (≈160%) as well as high optical transparency (>86% at 550 nm) can be realized simultaneously in SnO2 nanofiber webs. Moreover, the mechanical stretchability of SnO2 nanowebs can be further improved along with the optical transparency by precisely controlling the nanofiber density. The as-prepared freestanding nanowebs can be laminated onto curved surfaces by conformal contact. It is demonstrated that the fully exposed SnO2 nanowebs can be used as wearable UV photodetectors, showing reliable optoelectronic performance and remarkable tolerance to repeated complex deformations with body movements.

Fast lithium-ionic conduction in a new complex hydride-sulphide crystalline phase

A new crystalline phase derived from a 90LiBH4:10P2S5 mixture displays high lithium-ionic conductivity of log(σ/S cm(-1)) = -3.0 at 300 K. It is stable up to 473 K and has both a wide potential window of 0-5 V and favorable mechanical properties for battery assembly. Its incorporation into a bulk-type all-solid-state TiS2/InLi battery enabled repeated battery operation at 300 K.

Platinized Graphene/ceramics Nano-sandwiched Architectures and Electrodes with Outstanding Performance for PEM Fuel Cells

For the first time a novel oxygen reduction catalyst with a 3D platinized graphene/nano-ceramic sandwiched architecture is successfully prepared by an unusual method. Herein the specific gravity of graphene nanosheets (GNS) is tailored by platinizing graphene in advance to shorten the difference in the specific gravity between carbon and SiC materials, and then nano-SiC is well intercalated into GNS interlayers. This nano-architecture with highly dispersed Pt nanoparticles exhibits a very high oxygen reduction reaction (ORR) activity and polymer electrolyte membrane (PEM) fuel cell performance. The mass activity of half cells is 1.6 times of that of the GNS supported Pt, and 2.4 times that of the commercial Pt/C catalyst, respectively. Moreover, after an accelerated stress test our catalyst shows a predominantly electrochemical stability compared with benchmarks. Further fuel cell tests show a maximum power density as high as 747 mW/cm(2) at low Pt loading, which is more than 2 times higher than that of fuel cells with the pristine graphene electrode.

Brominated flame retardants in food and environmental samples from a production area in China: concentrations and human exposure assessment

Human exposure to brominated flame retardants (BFRs: decabromodiphenyl ether (BDE209), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), pentabromotoluene (PBT), 1,2,3,4,5-pentabromobenzene (PBBz), and 2,3,5,6-tetrabromo-p-xylene (TBX)) in a brominated flame retardant production area (Weifang, Shandong Province, China) was estimated. Thirty food samples, 14 air samples, and 13 indoor dust samples were analyzed. BDE209 and DBDPE were the dominant BFRs in all samples. Higher alternative brominated flame retardant (including DBDPE, HBB, PBEB, PBT, PBBz, and TBX) concentrations were found in vegetables than in fish and meat; thus, plant-original foods might be important alternative BFR sources in the study area. The BDE209 and alternative BFR concentrations in air were 1.5×10(4) to 2.2×10(5) and 620 to 3.6×10(4) pg/m3, respectively. Mean total BFR exposures through the diet, inhalation, and indoor dust ingestion were 570, 3000, and 69 ng/d, respectively (16, 82, and 2% of total intake, respectively). Inhalation was the dominant BFR source except for DBDPE, for which diet dominated. BDE209 contributed 85% of the total BFR intake in the study area.

Effects of harmine, an acetylcholinesterase inhibitor, on spatial learning and memory of APP/PS1 transgenic mice and scopolamine-induced memory impairment mice

Harmine, a β-carboline alkaloid present in Peganum harmala with a wide spectrum of pharmacological activities, has been shown to exert strong inhibition against acetylcholinesterase in vitro. However, whether it can rescue the impaired cognition has not been elucidated yet. In current study, we examined its effects on scopolamine-induced memory impairment mice and APP/PS1 transgenic mice, one of the models for Alzheimer's disease, using Morris Water Maze test. In addition, whether harmine could penetrate blood brain barrier, interact with and inhibit acetylcholinesterase, and activate downstream signaling network was also investigated. Our results showed that harmine (20mg/kg) administered by oral gavage for 2 weeks could effectively enhance the spatial cognition of C57BL/6 mice impaired by intraperitoneal injection of scopolamine (1mg/kg). Meanwhile, long-term consumption of harmine (20mg/kg) for 10 weeks also slightly benefited the impaired memory of APP/PS1 mice. Furthermore, harmine could pass through blood brain barrier, penetrate into the brain parenchyma shortly after oral administration, and modulate the expression of Egr-1, c-Jun and c-Fos. Molecular docking assay disclosed that harmine molecule could directly dock into the catalytic active site of acetylcholinesterase, which was partially confirmed by its in vivo inhibitory activity on acetylcholinesterase. Taken together, all these results suggested that harmine could ameliorate impaired memory by enhancement of cholinergic neurotransmission via inhibiting the activity of acetylcholinesterase, which may contribute to its clinical use in the therapy of neurological diseases characterized with acetylcholinesterase deficiency.

Inhibition of Drp1 by Mdivi-1 attenuates cerebral ischemic injury via inhibition of the mitochondria-dependent apoptotic pathway after cardiac arrest

Mitochondrial fission is predominantly controlled by the activity of dynamin-related protein1 (Drp1), which has been reported to be involved in mitochondria apoptosis pathways. However, the role of Drp1 in a rat model of cardiac arrest remains unknown. In this study, we found that activation of Drp1 in the mitochondria was increased after cardiac arrest and inhibition of Drp1 by 1.2 mg/kg of mitochondrial division inhibitor-1 (Mdivi-1) administration after the restoration of spontaneous circulation (ROSC) significantly protected against cerebral ischemic injury, shown by the increased 72-h survival rate and improved neurological function. Moreover, the increase of the vital neuron and the reduction of cytochrome c (CytC) release, apoptosis-inducing factor (AIF) translocation and caspase-3 activation in the brain indicate that this protection might result from the suppression of neuron apoptosis. Altogether, these results indicated that Drp1 is activated after cardiac arrest and the inhibition of Drp1 is protective against cerebral ischemic injury in a rat of cardiac arrest model via inhibition of the mitochondrial apoptosis pathway.

The physical mechanism of magnetic field controlled magnetocaloric effect and magnetoresistance in bulk PrGa compound

The PrGa compound shows excellent performance on the magnetocaloric effect (MCE) and magnetoresistance (MR). The physical mechanism of MCE and MR in PrGa compound was investigated and elaborated in detail on the basis of magnetic measurement, heat capacity measurement and neutron powder diffraction (NPD) experiment. New types of magnetic structure and magnetic transition are found. The results of the NPD along with the saturation magnetic moment (MS) and magnetic entropy (SM) indicate that the magnetic moments are randomly distributed within the equivalent conical surface in the ferromagnetic (FM) temperature range. PrGa compound undergoes an FM to FM transition and an FM to paramagnetic (PM) transition as temperature increases. The magnetizing process was discussed in detail and the physical mechanism of the magnetic field controlled magnetocaloric effect (MCE) and the magnetoresistance (MR) was studied. The formation of the plateau on MCE curve was explained and MR was calculated in detail on the basis of the magnetic structure and the analysis of the magnetizing process. The experimental results are in excellent agreement with the calculations. Finally, the expression of MR = β(T)X(2) and its application conditions were discussed, where X is M(H)/Meff, and Meff is the paramagnetic effective moment.

Significance of Onodera's prognostic nutritional index in patients with colorectal cancer: a large cohort study in a single Chinese institution

The preoperative nutritional and immunological statuses have an important impact in predicting the survival outcome of patients with various types of malignant tumors. Our study aimed to explore the clinical significance and predictive prognostic potential of Onodera’s prognostic nutritional index (PNI) in patients with colorectal carcinoma. This retrospective study included a total of 1321 patients who were diagnosed with colorectal cancer and who had been surgically treated between January 1994 and December 2007. The PNI level was determined according the following formula: 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count (per mm³). The impact of PNI on clinicopathological features and overall survival (OS) was determined. The optimal cutoff value of PNI was set at 45. Patients in the low-PNI group had a greater potential to have aggressive histological features, advanced tumors (T), nodal involvement (N), metastasis (M), and TNM stage than those in the high-PNI group. The low-PNI group had a worse OS than the high-PNI group (5-year survival rate 56.1 vs 64.8 %, respectively; P < 0.05). Furthermore, the PNI value was an independent prognostic factor for colorectal cancer in this study. The OS was significantly lower in the low-PNI group than in the high-PNI group in patients with TNM stage II and III diseases. Preoperative PNI is a simple and useful marker to predict clinicopathological features and long-term survival outcome in patients with colorectal carcinoma. PNI analysis should be included in the routine assessment of patients with locally advanced colorectal cancer.

Repairing rabbit radial defects by combining bone marrow stroma stem cells with bone scaffold material comprising a core-cladding structure

We prepared a bone scaffold material comprising a PLGA/β-TCP core and a Type I collagen cladding, and recombined it with bone marrow stroma stem cells (BMSCs) to evaluate its potential for use in bone tissue engineering by in vivo and in vitro experiments. PLGA/β-TCP without a cladding was used for comparison. The adherence rate of the BMSCs to the scaffold was determined by cell counting. Cell proliferation rate was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The osteogenic capability was evaluated by alkaline phosphatase activity. The scaffold materials were recombined with the BMSCs and implanted into a large segmental rabbit radial defect model to evaluate defect repair. Osteogenesis was assessed in the scaffold materials by histological and double immunofluorescence labeling, etc. The adherence number, proliferation number, and alkaline phosphatase expression of the cells on the bone scaffold material with core-cladding structure were significantly higher than the corresponding values in the PLGA/β-TCP composite scaffold material (P < 0.05). An in vivo test indicated that the bone scaffold material with core-cladding structure completely degraded at the bone defect site and bone formation was completed. The rabbit large sentimental radial defect was successfully repaired. The degradation and osteogenesis rates matched well. The bone scaffold with core-cladding structure exhibited better osteogenic activity and capacity to repair a large segmental bone defect compared to the PLGA/β-TCP composite scaffold. The bone scaffold with core-cladding structure has excellent physical properties and biocompatibility. It is an ideal scaffold material for bone tissue engineering.

[Relationship between occupational stressors and serum levels of thyroid hormones in policemen]

OBJECTIVE

To explore the relationship of occupational stressors with the serum levels of triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH).

METHODS

Using convenience sampling and cluster sampling methods, 225 policemen from a local police station in China were enrolled as subjects. Questionnaires were used to investigate demographic features and occupational stressors in those subjects. The serum levels of T3, T4, and TSH were measured by radioimmunoassay. The SPSS 13.0 software was used to perform t test or analysis of variance, partial correlation analysis, and multivariate non-conditional logistic regression analysis.

RESULTS

Reward was positively correlated with the level of T3(P<0.05). Daily tension was positively correlated with the level of T4(P<0.05). Psychological demand, effort, and daily tension were negatively correlated with the level of TSH (all P<0.05). The quality of sleep was positively correlated with the level of TSH (P<0.05). The logistic regression analysis revealed that the risk of increase in T3 level in the group with a high score for daily tension was 3.19-fold higher than that in the group with a low score, while the risk of increase in T3 level in the group with a high score for negative emotion was 1.32-fold higher than that in the group with a low score. The risk of increase in TSH level in the group with a high score for negative emotion was 0.43-fold that in the group with a low score.

CONCLUSION

The occupational stressors are correlated with the serum levels of thyroid hormones. Occupational stress can result in an increase in T3 level and a decrease in TSH level. However, occupational stress has no effect on T4 level.

[The effect of occupational stress on depression symptoms among 244 policemen in a city]

OBJECTIVE

To explore the influence of occupational stress related factors on depression symptoms among 244 policemen in a city in China.

METHODS

In May 2011, 287 policemen from a city public security bureau were recruited to this survey by cluster sampling method. We deleted questionnaires which include missing variables on demographic characteristics and factors associated with occupational stress questionnaires which include over 3 missing items. 244 policemen were included in this study. Depression symptoms and occupational stressors were measured using Chinese version of depression self-reported questionnaire, job content questionnaire, Chinese version of effort-reward imbalances questionnaire, job hazard scale and occupational stress inventory. Depression symptom scores and the relationship between the variables and occupational stress were analyzed by Spearman correlation analysis and multiple regression analysis.

RESULTS

The Median (P25-P75) of depression symptom scores of all respondents was 16.50 (11.00-25.00). 144 were policemen with no depression symptoms and 100 were with depression symptoms. The median (P25-P75) of depression symptoms scores among policemen with length of serves <10, 10-19, 20-29 and ≥30 was 17.00 (8.00-26.00), 16.00 (11.00-24.50), 19.00 (12.00-27.00), and 12.00 (6.25-15.00), respectively. The difference of scores was significant among length of serves groups (χ2=9.52, P=0.023). The scores of psychological demands, sleep disorder, daily life stress and negative affectivity among policemen with depression symptoms were 17.00 (8.00-26.00), 16.00 (11.00-24.50), 19.00 (12.00-27.00), and 12.00 (6.25-15.00), respectively, which were higher than those with no depression symptoms (24.00 (22.00-25.00), 8.00 (5.00-13.00), 8.00 (6.00-10.00), 1.00 (0-2.75)), and the differences were significant (Z=3.82, 5.39, 5.15, 6.41, P<0.001). Spearman correlation analysis revealed that depression symptoms score was positively related to sleep disorder, commitment effort, psychological demands, daily life stress, negative affectivity and job hazards scores. Correlations coefficient were 0.44, 0.28, 0.28, 0.33, 0.38, 0.44, and 0.38, respectively (P<0.001). Multiple linear regression analysis indicated that self-esteem, daily life stress and negative affectivity had bigger contribution on the depression symptoms scores. The standard regression coefficient was -0.46, 0.19 and 0.13, respectively (P<0.001, P=0.001, P=0.030).

CONCLUSION

Sleep disorder, commitment effort, psychological demands, daily life stress, negative affectivity and job hazards scores were the inducement of depression symptoms for policemen. To reduce the daily life stress, negative affectivity and improve the quality of sleep, add to self-esteem, reward and social support have positive effects on reducing the occurrence of depressive symptoms for police.