N-甲基羟胺盐酸盐的热分解机理的理论研究

为深入研究N-甲基羟胺盐酸盐(NMHH)热分解的反应特征,应用密度泛函理论,在w B97xd/6-311++g(2df,2pd)水平下,对NMHH的初步分解产物N-甲基羟胺(NMHA)及质子化的NMHA热分解反应中涉及的反应物、过渡态、中间体、产物的几何结构和能量情况进行了优化计算,提出了可能的热分解路径。结果表明,NMHA与质子化NMHA均存在两种热分解路径。NMHA在两条路径下分解需越过的能垒为250.75 k J/mol与428.64 k J/mol,而质子化NMHA在对应分解路径下需要越过的能垒分别为217.19 k J/mol与286.77k J/mol。在对应路径下质子化NMHA分解需越过的能垒明显低于NMHA的直接分解,并且随着反应的持续进行,质子化的NMHA的形成和分解将越来越容易发生。这表明NMHH的分解具有自催化特征,与试验结果吻合。     

寒冷地区不同煤样冻黏强度试验研究

寒冷地区煤炭运输设备上煤的冻黏严重影响煤炭运输的安全与效率,为分析各地不同煤样的冻黏强度特性及原因,选取各地5个存在冻黏现象煤矿的煤样,测试其在Q235和UHMWPE材料上的冻黏强度,并检测5种煤样的外在水质量分数、粒度和孔容分布,结果表明:在亲水性Q235材料上,内蒙古锡林浩特煤样冻黏强度最高(2.58 MPa),其次是辽宁铁法煤样(2.02 MPa)和黑龙江双鸭山煤样(1.36 MPa),北京大安山(0.773 MPa)和木城涧煤样(0.689 MPa)较低;不同煤样在疏水性UHMWPE材料上的冻黏强度分布在0.159~0.230 MPa。各煤样因煤质、采掘破碎工况、煤化程度等因素导致其粒度和孔容分布不同,使各自外在水质量分数不同,进而导致煤样在亲水性Q235材料上冻黏强度差别明显,外在水质量分数高的煤样冻黏强度相对较高;在UHMWPE材料上,各煤样的冻黏强度因材料的疏水性而对外在水质量分数差异不敏感,因而普遍很低且差别很小,可见采用UHMWPE基体材料对各地煤在运输设备上的冻黏具有一定防治作用。     

东营市地下水碘化物的空间分布特征及影响分析

为研究东营市地下水碘化物的空间分布特征以及对环境和饮用水安全的影响,对域内的山前平原区和黄泛平原区分别布设了48个和47个调查点位。结果表明:东营市地下水碘化物质量浓度均值达到(0.247±0.263) mg/L,其环境质量呈现由南向北逐步恶化的变化趋势,超过90%的国土面积处于地下水环境质量标准Ⅳ类。山前平原区南部是东营市唯一具备可饮用地下水的区域,域内以适碘地区为主,缺碘地区和高碘地区分别位于区域东南部和第二次海侵古海岸线附近。总体上,可饮用地下水处于中等缺碘水平,海(咸)水入侵已成为影响可饮用地下水适碘地区范围的关键因素,需引起高度关注。地下水所处的环境地质概况、海(咸)水入侵和大气降水是影响碘化物空间分布的重要因素。     

Antecedents and consequences of satisfaction with work–family balance: A moderating role of perceived insider status

This study developed a moderated mediation model to investigate how family‐supportive paid leave and supervision affect employees' satisfaction with work–family balance and in turn their affective organizational commitment and supervisor‐directed organizational citizenship behavior depending on their perceived insider status in the organization. Our analysis of data collected from 118 employee–supervisor dyads in Korean organizations revealed that satisfaction with work–family balance mediated the linkages from family‐supportive supervision to affective organizational commitment and supervisor‐directed organizational citizenship behavior, and the linkage from family‐supportive paid leave to affective organizational commitment. Results further showed that the entire mediational process for family‐supportive supervision was more pronounced for those who perceived themselves to be an insider of their organizations, while the same pattern was not found for the meditational process related to family‐supportive paid leave. Our findings provide theoretical implications for work–family balance research and offer practical suggestions to make employees satisfied with work–family balance.     

Study of chest injuries to 3-year-old child occupants seated in impact shield and 5-point harness CRSs

Objective: The objective of this study was to investigate whether the 5-point harness or the impact shield child restraint system (CRS) or both have the potential to cause chest injuries to children. This is determined by examining whether the loading to the chest reaches the internal organ injury threshold for children.

Method: The chest injury risk to a child occupant in a CRS was investigated using Q3 dummy tests, finite element (FE) simulations (Q3 dummy and human models), and animal tests. The investigation was done for 2 types of CRSs (i.e., the impact shield CRS and 5-point harness CRS) based on the UN R44 dynamic test specifications.

Results: The tests using a Q3 dummy indicated that although the chest deflection of the dummy in the impact shield CRS was large, it was less than the injury threshold (40 mm). Computational biomechanics simulations (using finite element FE analysis) showed that the Q3 dummy's chest is loaded by the shield and deforms substantially under this load. To clarify whether chest injuries due to chest compression can occur with an impact shield or with the 5-point harness CRS, 7 experiments were performed using Tibetan miniature pigs with weights ranging from 9.7 to 13 kg. Severe chest and abdominal injuries (lung contusion, coronary artery laceration, liver laceration) were found in the tests using the impact shield CRS. No chest injuries were present when using the 5-point harness CRS.

Conclusion: When using the impact shield CRS, the chest deformed substantially in dummy tests and FE simulations, and chest and abdominal injuries were observed in pig tests. It is possible that these chest injuries could also occur to child occupants sitting in the impact shield CRS.     

Comparison of physical technologies for biomass control in biofilters treating gaseous toluene

Excessive accumulation of biomass within gas-phase biofilters often results in the deterioration of removal performance. Compared with chemical and biological technologies, physical technologies are more effective in removing biomass and inducing less inhibition of the biofilter performance. This study applied different physical technologies, namely, air sparging, mechanical mixing, and washing with water at various temperatures, to remove excess biomass in biofilters treating toluene. Filter pressure drop, removed dry biomass, biofilter performance, and microbial metabolic characteristics were analyzed to evaluate the effectiveness of the methods. Results showed that air sparging was inefficient for biomass removal (1 kg dry biomass/m³ filter), whereas mechanical mixing significantly inhibited removal efficiencies (<30%). Washing of the packing with fluids was feasible, and hot fluids can remove a large amount of biomass. However, hot fluids reduce microbial activity and inhibit removal performance. Washing of the packing with either 20°C or 50°C water showed efficiency as >3 kg dry biomass/m³ filter can be removed at both temperatures with removal efficiencies at approximately 40% after treatment. Finally, different technologies were compared and summarized to propose an optimized strategy of biomass control for industrial biofilters.

Implications: This study is to apply different physical technologies, namely, air sparging, mechanical mixing, and washing with water of different temperatures, to remove the excess biomass in biofilters treating toluene. The filter pressure drop, removed dry biomass, biofilter performance, and microbial metabolic characteristics were all analyzed to evaluate the effectiveness of the methods. The results of this study provide useful information regarding biomass control of industrial biofilters.     

Conservation prioritization with machine learning predictions for the black-necked crane Grus nigricollis,a flagship species on the Tibetan Plateau for 2070

Regional Environmental Change - Ongoing global climate change greatly alters the distribution of species, and such impacts are even amplified on the Tibetan Plateau. The black-necked crane (Grus...     

The effect of plasma components on hemoglobin release test in red blood cells (RBC)

Electrophoresis release test (ERT) was established by our lab to observe the re-released hemoglobin (Hb) from red blood cells (RBCs) and whole blood. In this study, ERT was performed to study the effects of different plasma components including plasma, serum, albumin, globulin, fibrinogen, glucose, amino acid, vitamin, insulin, hormone, and inorganic ions on re-released Hb from RBC and whole blood samples during ERT. The results showed that plasma, serum, albumin, globulin, compound amino acid, essential amino acid, vitamin C, insulin, hormone, NaCl, KCl, CaCl₂, and NaHCO₃^? decreased re-released RBC Hb; while glucose, vitamin B1, vitamin B2, and vitamin B12 elevated re-released RBC Hb. The differing effects of various plasma components on re-released Hb of RBC may play a significant role in blood conservation.     

大连地区唐氏筛查孕中期妇女羊水中甲状腺激素水平与PBDEs内暴露关系初探

多溴联苯醚(polybrominated diphenyl ethers,PBDEs)是一类常用的溴代阻燃剂,由于使用广泛,已成为普遍存在的环境污染物。研究表明,PBDEs具有内分泌干扰作用,影响甲状腺功能,对胚胎发育、婴幼儿及儿童的健康存在潜在的危害。本研究采集了100例具羊水穿刺指征的孕妇的孕中期羊水样本,采用罗氏全自动电化学发光免疫分析仪测定羊水中促甲状腺激素(TSH)、三碘甲状腺原氨酸(TT3)、游离三碘甲状腺原氨酸(FT3)、甲状腺素(TT4)、游离甲状腺素(FT4)、抗甲状腺过氧化酶抗体(TPOA)和抗甲状腺球蛋白抗体(TGA)的含量,用气相色谱-负化学源-质谱法测定羊水样品中16种PBDEs同系物含量。结果显示,羊水中TSH、TT3、FT3、TT4、FT4中位数分别为0.342μIU·m L-1、0.949 nmol·L-1、1.52 pmol·L-1、11.02 nmol·L-1和3.91pmol·L-1,95%参考区间值分别为0.174~0.872μIU·m L-1、0.835~1.01 nmol·L-1、1.26~2.72 pmol·L-1、9.42~20.68 nmol·L-1和2.16~6.35 pmol·L-1。具有唐氏筛查高风险和甲状腺激素水平低下的羊水样品中共检出6种BDEs(BDE-47、BDE-71、BDE-138、BDE-183、BDE-190、BDE-209),其中BDE-71、183和190在被检羊水样品中均被检出,并且,TSH水平低下的羊水中BDE-190和209负荷水平显著高于正常组。这些结果提示,大连地区孕中期妇女羊水存在PBEDs内暴露,并且PBDEs内暴露可能与羊水的甲状腺激素水平低下、尤其TSH水平升高有关,提示PBDEs暴露可能与胎儿中枢神经系统损伤产生的下丘脑-垂体-甲状腺(HPT)轴功能失调有关。因此,羊水PBDEs内暴露对新生儿出生结局的影响值得进一步关注。     

Pickling of chanterelle <Emphasis Type="Italic">Cantharellus cibarius</Emphasis> mushrooms highly reduce cadmium contamination

Mushrooms are considered as potential bio-remediation agents in soil polluted with heavy metals, while many species which efficiently accumulate them in flesh are edible. Question is if there is any possible culinary use of edible mushrooms with high heavy metal contents? This study aimed to investigate and discuss a fate of cadmium (Cd) in common household-treated fruitbodies of common chanterelle Cantharellus cibarius. The samples of Cantharellus cibarius Fr. were collected from five spatially distanced sites in Poland in 2011–2012. We examined from 267 to 358 fruiting bodies per collection, and in total 1565 fruiting bodies were used. Cadmium in fungal materials from all treatments and processes (mushrooms dried, deep frozen, blanched and pickled) was determined using validated methods by inductively coupled plasma mass spectrometry with dynamic reaction cell. Blanching of fresh chanterelles caused decrease of Cd by around 11 ± 7 to 36 ± 7%, while blanching of deep-frozen mushrooms by around 40 ± 6%. A rate of Cd decrease in chanterelles was similar when the fruiting bodies were blanched for 5 or 15 min and when used was potable or deionized water. Pickling of blanched chanterelles with a diluted vinegar marinade had a pronounced effect on further removal of Cd. Blanched chanterelles when pickled lost an extra 37–71% of Cd. Total leaching rate of Cd from fresh or deep-frozen fruitbodies of chanterelle when blanched and further pickled was between 77 ± 7 and 91 ± 4%. Blanching and pickling highly decreased content of Cd in C. cibarius.