How Good Are the Performances of Graphene and Boron Nitride Against the Wear of Copper?

We investigate the copper-wear-protective effects of graphene and boron nitride in single asperity sliding contact with a stiff diamond-coated atomic force microscopy (AFM)-tip. We find that both graphene and boron nitride retard the onset of wear of copper. The retardment of wear is larger with boron nitride than with graphene, which we explain based on their respective out-of-plane stiffnesses. The wear protective effect of boron nitride comes, however, at a price. The out-of-plane stiffness of two-dimensional materials also determines their friction coefficient in a wear-less friction regime. In this regime, a higher out-of-plane stiffness results in larger friction forces.     

Orthotopic liver transplantation in a patient with combined hemophilia A and B

A 38-year-old man with severe factor IX and mild factor VIII deficiencies complicated by cirrhosis secondary to chronic non-A non-B hepatitis underwent orthotopic liver transplantation as treatment for both the cirrhosis and his congenital coagulopathy. Intraoperative hemostasis was obtained with factor VII-depleted prothrombin complex concentrate and fresh frozen plasma. Factor VIII and factor IX levels were assayed frequently in the perioperative period, and both returned to normal within 24 hr and remained normal postoperatively. Liver transplantation can be considered as definitive therapy for hemophilia A and/or B with transfusion-related liver disease.     

电子线路板粉末浸出液重金属含量分析及其饲养斑马鱼前后鱼体内镍铬水平的变化

目的通过分析电子线路板粉末中主要重金属成分的含量及其浸出液中重金属含量,分析其中可溶性重金属盐类所占的比重,同时通过动物实验初步探讨该废弃物溶出液饲养斑马鱼后镍镉在斑马鱼体内变化的情况。方法通过原子吸收分光光度法分析并对比电子线路板粉末和浸出液中铜、铅、锌、镉、镍、铬、铁、锰的含量,初步分析该粉末中重金属的溶出情况及对水体可能的影响。通过对不同剂量浸出液饲养的斑马鱼体内镍铬含量的分析,探讨其在斑马鱼体内变化的情况。结果电子线路板粉末中含量最高的前3位金属分别是铜、铅和铁,分别达64.1、55.6和25.8 mg/kg;金属铬未被检出。浸出液中含量最高的前3位金属分别是铜、锰和镉,其含量分别达1.440、0.322和0.088 mg/L。在实验室饲养斑马鱼中,虽然对照组、低剂量组和中剂量组检测结果有一些不同,但其差异无统计学意义。结论电子线路板拆解废弃物中铜、锰、镉溶出量较高,应在现场监测中重点关注。用一定浓度的浸出液饲养斑马鱼体,其体内的镍铬水平基本无变化。     

基于中国居民疾病发病和死亡情况的环境重金属污染健康风险评估标准探讨

重金属污染日趋严峻,严重影响了人们的生活质量,而健康风险评估可有效地应用于环境管理决策.基于健康风险评估标准制定的原则,通过结合中国居民慢性病的患病率和死亡率现状,参照不同国家的健康风险评估标准,对适合中国人群的环境重金属污染健康风险评估标准进行探讨.     

Investigation of inflammation inducing substances in PM2.5 particles by an elimination method using thermal decomposition

The substances associated with PM2.5‐induced inflammatory response were investigated using an elimination method. PM2.5 were heated at temperatures of 120, 250, and 360°C. The results demonstrated microbial substances such as LPS and b‐glucan, and chemicals including BaP, 1,2‐NQ, and 9,10‐PQ were reduced drastically in PM2.5 heated at 120°C. On the other hand, DBA, 7,12‐BAQ, and BaP‐1,6‐Q were not noticeably reduced. Most of these substances had disappeared in PM2.5 heated at 250°C and 360°C. Metals (eg, Fe, Cu, Cr, Ni) in PM2.5 exhibited a slight thermo‐dependent increase. RAW264.7 macrophages with or without NAC were exposed to unheated PM2.5, oxidative stress‐related and unrelated inflammatory responses were induced. PM2.5‐induced lung inflammation in mice is caused mainly by thermo‐sensitive substances (LPS, b‐glucan, BaP, 1,2‐NQ, 9,10‐PQ, etc.). Also, a slight involvement of thermo‐resistant substances (DBA, 7,12‐BAQ, BaP‐1,6‐Q, etc.) and transition metals was observed. The thermal decomposition method could assist to evaluate the PM2.5‐induded lung inflammation.     

Relationship between blood cadmium,lead, and serum thyroid measures in US adults – the National Health and Nutrition Examination Survey (NHANES) 2007–2010

Experimental studies have shown that both cadmium (Cd) and lead have potent endocrine disrupting activity. However, studies on whether these heavy metals disrupt thyroid system in humans, especially in general populations with low levels of exposure, are sparse. The study analyzed 6,231 participants aged 20 and older with measurements from 2007–2010 of the National Health and Nutrition Examination Survey (NHANES) to investigate whether whole blood Cd and lead level are associated with serum thyroid hormones measures. Our study suggests that thyroid function may be disrupted by both Cd and lead exposures in the general population and the specific roles of Cd and lead exposure on thyroid axis may differ by sex. However, the mechanisms by which these heavy metals may disrupt thyroid system function in general population needs to be further investigated.     

不同产地厚朴中重金属及有害元素检测

目的:检测不同产地厚朴中重金属及有害元素含量。方法:采用原子荧光光度法和原子吸收分光光度法对全国8省11个不同产地厚朴中铅、镉、砷、汞、铜进行测定。结果:不同产地厚朴中所含重金属及有害元素的量有一定差异,11个样品中除有4个样品的铅含量较高外,其余均符合"药用植物及制剂外经贸绿色行业标准"要求。结论:所建立的方法可行,其含量测定结果可为厚朴药材的规范化种植和质量评价提供参考。     

紫外分光光度法测定蜈蚣甘草散中重金属的含量

目的：测定蜈蚣甘草散中重金属的含量。方法：蜈蚣甘草散灰化后用硫化钠显色,用紫外分光光度法测定蜈蚣甘草散中重金属的含量。灰化温度550℃,时间2h;测定条件：pH3．0-3．5,波长202nm。结果：线性范围0-50μg,平均加样回收率为99．52％,RSD1．82％。结论：本方法可靠,稳定性、重现性好,可作为蜈蚣甘草散中重金属限量控制的方法。     

An Enhanced Understanding of the Powder Bed Fusion–Laser Beam Processing of Mg-Y3.9wt%-Nd3wt%-Zr0.5wt% (WE43) Alloy through Thermodynamic Modeling and Experimental Characterization

Powder Bed Fusion–Laser Beam (PBF–LB) processing of magnesium (Mg) alloys is gaining increasing attention due to the possibility of producing complex biodegradable implants for improved healing of large bone defects. However, the understanding of the correlation between the PBF–LB process parameters and the microstructure formed in Mg alloys remains limited. Thus, the purpose of this study was to enhance the understanding of the effect of the PBF–LB process parameters on the microstructure of Mg alloys by investigating the applicability of computational thermodynamic modelling and verifying the results experimentally. Thus, PBF–LB process parameters were optimized for a Mg WE43 alloy (Mg-Y_3.9wt%-Nd_3wt%-Zr_0.5wt%) on a commercially available machine. Two sets of process parameters successfully produced sample densities >99.4%. Thermodynamic computations based on the Calphad method were employed to predict the phases present in the processed material. Phases experimentally established for both processing parameters included α-Mg, Y₂O₃, Mg₃Nd, Mg₂₄Y₅ and hcp-Zr. Phases α-Mg, Mg₂₄Y₅ and hcp-Zr were also predicted by the calculations. In conclusion, the extent of the applicability of thermodynamic modeling was shown, and the understanding of the correlation between the PBF–LB process parameters and the formed microstructure was enhanced, thus increasing the viability of the PBF–LB process for Mg alloys.