Occupational exposure to commercial decabromodiphenyl ether in workers manufacturing or handling flame-retarded rubber

Commercial decabromodiphenyl ether (DecaBDE) is commonly used as a flame retardant in different electrical and textile applications. It is also used in the production of flame-retarded rubber compound. DecaBDE is the major technical polybrominated diphenyl ether (PBDE) in use today and consists mainly of decabromodiphenyl ether (BDE-209). PBDEs, including BDE-209, are well-known environmental pollutants, ubiquitous both in aquatic and terrestrial environments. The aim of the present study was to assess the exposure to PBDEs in workers manufacturing or handling rubber which was flame retarded with DecaBDE. A referent group, abattoir workers (slaughterhouse workers), with no occupational exposure to PBDEs, was also investigated. Moreover, the methodology for analysis of PBDEs in serum was refined, with special emphasis on congeners with a high number of bromine substituents, i.e., octa- to decaBDEs. The highest BDE-209 concentration observed among the rubber workers was 280 pmol/g lipid weight (I.w.) (270 ng/g I.w.). The median concentration of BDE-209 among rubber workers was 37 pmol/g I.w. (35 ng/g I.w.). Among referents, the median was 2.5 (range 0.92-9.7) pmol/g I.w. (median 2.4 ng/g I.w.). In rubber workers the BDE-209 concentrations were up to 32% (median 4%) of the 2,2',4,4',5,5'-chlorobiphenyl (CB-153) concentrations, on a molar basis, whereas the referents had BDE-209 concentrations which were similar to that of 2,2',4,4'-bromodiphenyl ether (BDE-47), below 1.4% (median 0.3%) of the CB-153 concentration. Concentrations of all nonabromodiphenyl ethers (nonaBDEs) and several octabrmodiphenyl ethers (octaBDEs) congeners, including BDE-203, were also elevated among the rubber workers, with 2.5- to 11-fold higher median concentrations, compared to the referents. The results confirm a significant uptake of BDE-209 in the workers exposed to DecaBDE and indicate a potential for in vivo formation of lower BDEs in these persons.     

Social connectedness and mothering: Effects of maternal employment and maternal absence.

We conducted two separate studies to test N. Chodorow's (1978) theory concerning the relationship between mothering and social connectedness, that is, a sense of self in relation to others. In two correlational studies, we examined the effects of maternal employment and maternal absence (because of death or divorce) on young adults' social connectedness, as measured by the Interpersonal Orientation (IO) Scale (W. C. Swap and J. Z. Rubin; see record 1983-22471-001). Although differences in maternal employment were not related to IO, maternal absence was related to IO. Daughters whose mothers had been absent since the daughters' early childhood rated themselves lowest on IO; this was especially true of daughters who did not report having a mother substitute. This finding provides support for Chodorow's theory because it documents a predicted sex difference, a predicted effect of "mothering" versus "fathering," and a predicted difference between early (i.e., preoedipal) and later absence. Future empirical work on moderators of child-rearing experience is warranted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cellular Mechanisms of the Anti-Arrhythmic Effect of Cardiac PDE2 Overexpression

Background: Phosphodiesterases (PDE) critically regulate myocardial cAMP and cGMP levels. PDE2 is stimulated by cGMP to hydrolyze cAMP, mediating a negative crosstalk between both pathways. PDE2 upregulation in heart failure contributes to desensitization to β-adrenergic overstimulation. After isoprenaline (ISO) injections, PDE2 overexpressing mice (PDE2 OE) were protected against ventricular arrhythmia. Here, we investigate the mechanisms underlying the effects of PDE2 OE on susceptibility to arrhythmias. Methods: Cellular arrhythmia, ion currents, and Ca²⁺-sparks were assessed in ventricular cardiomyocytes from PDE2 OE and WT littermates. Results: Under basal conditions, action potential (AP) morphology were similar in PDE2 OE and WT. ISO stimulation significantly increased the incidence of afterdepolarizations and spontaneous APs in WT, which was markedly reduced in PDE2 OE. The ISO-induced increase in I_CaL seen in WT was prevented in PDE2 OE. Moreover, the ISO-induced, Epac- and CaMKII-dependent increase in I_NaL and Ca²⁺-spark frequency was blunted in PDE2 OE, while the effect of direct Epac activation was similar in both groups. Finally, PDE2 inhibition facilitated arrhythmic events in ex vivo perfused WT hearts after reperfusion injury. Conclusion: Higher PDE2 abundance protects against ISO-induced cardiac arrhythmia by preventing the Epac- and CaMKII-mediated increases of cellular triggers. Thus, activating myocardial PDE2 may represent a novel intracellular anti-arrhythmic therapeutic strategy in HF.     

相变燃料电极实现固体氧化物电池高效可逆CO/CO2转化

固体氧化物电池可实现CO/CO₂的可逆转化,在电能和化学能相互转化过程中显示出巨大潜力.然而,其商业化进展一直受到燃料极抗积碳性能差的限制.本工作中,我们发展了一种CoFe合金纳米颗粒和Ruddlesden-Popper层状结构Sr₃Fe_1.25Mo_0.75O₇-δ复合新型燃料电极(CoFe-SFM),其可以通过钙钛矿Sr₂Fe_7/6Mo_0.5Co_1/3O_6-δ在还原气氛中退火发生相变得到.电化学阻抗谱和弛豫时间分步法分析可知CoFe-SFM电极通过改善体相氧化学扩散能力和表面氧交换过程来增强CO氧化和CO₂还原动力学.在固体氧化物燃料电池模式下,800℃的最大功率达到259 mW cm^-2;在固体氧化物电解电池模式下,1.3 V工作电压下单电池的电解电流密度为-0.453 A cm^-2,都远超对比电极材料.在20次SOFC-SOEC循环操作条件下,CoFe-SFM燃料极依然保持稳定的微结构和抗积碳性能,电池性能保持良好.该工作可为CO₂转化、抗积碳电极材料设计和提升电极表界面反应动力学提供一定的指导作用.     

Making Ultrafast High‐Capacity Anodes for Lithium‐Ion Batteries via Antimony Doping of Nanosized Tin Oxide/Graphene Composites

Tin oxide‐based materials attract increasing attention as anodes in lithium‐ion batteries due to their high theoretical capacity, low cost, and high abundance. Composites of such materials with a carbonaceous matrix such as graphene are particularly promising, as they can overcome the limitations of the individual materials. The fabrication of antimony‐doped tin oxide (ATO)/graphene hybrid nanocomposites is described with high reversible capacity and superior rate performance using a microwave assisted in situ synthesis in tert‐butyl alcohol. This reaction enables the growth of ultrasmall ATO nanoparticles with sizes below 3 nm on the surface of graphene, providing a composite anode material with a high electric conductivity and high structural stability. Antimony doping results in greatly increased lithium insertion rates of this conversion‐type anode and an improved cycling stability, presumably due to the increased electrical conductivity. The uniform composites feature gravimetric capacity of 1226 mAh g^?1 at the charging rate 1C and still a high capacity of 577 mAh g^?1 at very high charging rates of up to 60C, as compared to 93 mAh g^?1 at 60C for the undoped composite synthesized in a similar way. At the same time, the antimony‐doped anodes demonstrate excellent stability with a capacity retention of 77% after 1000 cycles.     

Implications of error and uncertainty for an environmental planning scenario: A sensitivity analysis of GIS-based variables in a reserve design exercise

The creation of a protected area network is used as an example to demonstrate the potential effects of uncertainty and error in geographic information systems (GIS) data on our ability to make reliable land planning decisions. A graph-based model of the landscape was employed where nodes represent habitat patches, edges represent inter-node paths, and inter-node distance is measured as the least-cost path according to a resistance surface. Optimal reserve networks were generated by considering the trade-offs between area and connectivity, as measured according to correlation length. A “base case” network was first created and then varied according to the land cover categorical definitions used to extract the patch map, the resistance surface, and the cell size used to represent the raster patch and resistance surfaces. The largest recommended network was over 101% larger than the smallest recommended network. The identity of the small patches predicted to be critical stepping stones and the projected effectiveness of the alternative network configurations was widely disparate. Our results support the need for a precautionary approach to compensate for data uncertainties. Through sensitivity analysis, alternative scenarios can be created for decision-makers that highlight the most conservative options and emphasize the potential uncertainties surrounding the outputs.     

Electron capture dissociation of oligosaccharides ionized with alkali, alkaline Earth, and transition metals

We extend the application of electron capture dissociation (ECD) (which requires at least two charges) to oligosaccharides without basic functionalities by utilizing alkali, alkaline earth, and transition metals (Na+, K+, Ca2+, Ba2+, Mg2+, Mn2+, Co2+, and Zn2+) as charge carriers in electrospray ionization. Both linear and branched oligosaccharides were examined, including maltoheptoase, p-lacto-N-hexaose, and an N-linked glycan from human alpha1-acid glycoprotein. For comparison, infrared multiphoton dissociation (IRMPD) was also applied to all oligosaccharide species. We show that, for certain metal-adducted oligosaccharides, particularly maltoheptaose, cross-ring cleavage, which can provide saccharide linkage information, is the dominant fragmentation pathway in ECD. By contrast, glycosidic cleavages dominate in IRMPD although cross-ring fragmentation was also observed to varying degrees depending on metal ion type. The branched N-linked glycan did not fragment as easily following ECD compared to the linear oligosaccharides, presumably due to intramolecular noncovalent interactions. However, this limitation was partially overcome with a combined ECD/IRMPD approach (activated ion ECD). For all metal-adducted oligosaccharides, complementary structural information was obtained with ECD as compared to IRMPD. Our results demonstrate that ECD of metal-adducted oligosaccharides is a valuable tool for structural characterization of oligosaccharides.     

Infrared multiphoton dissociation and electron-induced dissociation as alternative MS/MS strategies for metabolite identification

A major challenge encountered in mass spectrometric metabolite analysis is the identification and structural characterization of metabolites. Fourier transform ion cyclotron resonance mass spectrometry is a valuable technique for metabolite structural determination because it provides accurate masses and allows for multiple MS/MS fragmentation strategies, including infrared multiphoton dissociation (IRMPD) and electron-induced dissociation (EID). Collision activated dissociation (CAD) is currently the most commonly used MS/MS technique for metabolite structural characterization. In contrast, IRMPD and EID have had very limited, if any, application for metabolite characterization. Here, we explore IRMPD and EID of phosphate-containing metabolites and compare the resulting fragmentation patterns to those of CAD. Our results show that CAD, IRMPD, and EID provide complementary structural information for phosphate-containing metabolites. Overall, CAD provided the most extensive fragmentation for smaller (<600 Da) phosphate-containing metabolites; however, IRMPD generated more extensive fragmentation for larger (>600 Da) phosphate-containing metabolites, particularly for species containing increased numbers of phosphate groups. EID generally provided complementary fragmentation to CAD and showed extensive fragmentation with relatively evenly abundant product ions, regardless of metabolite size. However, EID fragmentation efficiency is lower than those of CAD and IRMPD.