The reduction potentials of five organic carbonates commonly employed in lithium battery electrolytes, ethylene carbonate ͑EC͒, propylene carbonate ͑PC͒, diethyl carbonate ͑DEC͒, dimethyl carbonate ͑DMC͒, and vinylene carbonate ͑VC͒ were determined by cyclic voltammetry using inert ͑Au or glassy carbon͒ electrodes in tetrahydrofuran/LiClO 4 supporting electrolyte. The reduction potentials for all five organic carbonates were above 1 V ͑vs. Li/Li ϩ ͒. PC reduction was observed to have a significant kinetic hindrance. The measured reduction potentials for EC, DEC, and PC were consistent with thermodynamic values calculated using density functional theory ͑DFT͒ assuming one-electron reduction to the radical anion. The experimental values for VC and DMC were, however, much more positive than the calculated values, which we attribute to different reaction pathways. The role of VC as an additive in a PC-based electrolyte was investigated using conventional constant-current cycling combined with ex situ infrared spectroscopy and in situ atomic force microscopy ͑AFM͒. We confirmed stable cycling of a commercial li-ion battery carbon anode in a PC-based electrolyte with 5 mol % VC added. The preferential reduction of VC and the solid electrolyte interphase layer formation therefrom appears to inhibit PC cointercalation and subsequent graphite exfoliation.

Ethers and organic carbonates are commonly used as solvents in lithium battery electrolyte. It is important to determine the oxidation potentials of these organic solvents due to the high cathode potential (∼5 V) in many of these batteries. There are significant variations in the reported oxidation potentials for electrolytes containing these solvents. The factors contributing to the variation include the type of salt used in the electrolyte, composition of the electrode, and a somewhat arbitrary determination of the oxidation potential from the anodic cutoff current. We report here the application of density functional theory (DFT) to calculate solvent oxidation potentials assuming oxidation occurs via one-electron transfer to form the radical cation. No specific ion-ion, ion-solvent, or ion-electrode interactions are included. These values are then compared to the experimental observations. Eleven solvent molecules are studied: 1,2-dimethoxyethane, tetrahydrofuran, 1,3-dioxolane, diethylcarbonate, dimethylcarbonate, ethylmethylcarbonate, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, and catechol carbonate. Optimized geometries of the radical cations correlate well with the fragmentation patterns observed in mass spectrometry. The oxidation potentials of saturated carbonates are calculated to be approximately 1 V higher than the organic ethers, which is consistent with reported literature values. Quantitative comparison with experiment will require more careful measurements to eliminate other oxidation reactions and a standardized procedure for determining the oxidation potential. © 2001 The Electrochemical Society. All rights reserved.

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The first in situ measurements with scanning transmission X-ray microscopy (STXM) of an active electrochemical cell are reported. An electrochemical wet cell, consisting of an electrodeposited polyaniline thin film on a thin Au film covered by an overlayer of 1 M HCl solution sitting between two X-ray transparent silicon nitride windows, was assembled. X-ray absorption images and spatial and time-resolved spectra of this system under potential control were examined using the beamline 5.3.2 STXM at the Advanced Light Source. The chemical state of the polyaniline film was reversibly converted between reduced (leucoemeraldine) and oxidized (emeraldine chloride) states by changing the applied potential. The electrochemical changes were monitored by spatially resolved C 1s and N 1s X-ray absorption spectroscopy and chemical-state selective imaging. Comparison of differences between images at two energies at different potentials provided electrochemical contrast with a resolution better than 50 nm, thereby monitoring that component of the polyaniline film that was electrochemically active. Kinematic studies in the subsecond regime are demonstrated.

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Background Recurrent pregnancy loss (RPL) had said to be related to the angiotensin converting enzyme insertion/deletion polymorphisms (ACE I/D) gene polymorphisms. But the conclusions were controversial. This meta-analysis was conducted to investigate the real association in ACE I/D polymorphisms and RPL firstly. Methods Combine Pubmed Embase and HuGENet database in data analysis for this meta-analysis from October 2000 to November 2011. The metagen system was used to select the models and effects. Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of this association. Results 9 studies from six countries with 1264 RPL and 845 controls were included according to our criterion. Following the metagen system, we used the dominant model with random effects. The summary OR 01.61 (95% CI: 1.10-2.36, I 2 0 59.0%), which suggested the ACE D allele might increase the RPL risk in Asia (OR01.97, 95% CI: 1.31-2.98, I 2 0 44.4%), among Asians (OR01.69, 95% CI: 1.06-2.36, I 2 032.7%). In additional, after conducting sensitivity analysis, the results had no differences except for Caucasian subgroup reached to the significance (OR02.059, 95% CI: 1.455-2.914), so we couldn't ignore the relationship between the polymorphisms of ACE D/I gene and Caucasians yet. There seemed no publication bias in our eligible studies with Begg's test (P 0 0.867). Conclusions Results in this meta-analysis presented the positive function of the ACE I/D polymorphism in increasing the RPL risk. Furfure prospective studies were needed to confirm the precise relationship between the ACE I/D and RPL.

Most recurrent spontaneous miscarriages (RSMs) are attributed to 'unexplained' factors, the majority of which are immune factors. Furthermore, clinically, only a small number of RSM patients get early diagnosis by testing for antiphospholipid antibodies, whereas most of the patients, present no specific diagnostic indicators. We performed a meta-analysis of observational studies to detect the association between RSM and TNF-α levels. We searched PubMed, EMBase, ScienceDirect, Web of Science, and Chinese databases (including: Wanfang Data, CNKI, and VIP databases) for articles published up to 2014. Of the 151 initially identified studies, 11 case-control studies with 1371 patients were finally analyzed. Overall, baseline TNF-α levels were higher in patients than in controls. The standardized mean difference of the TNF-α levels of the patients was 2.82 units (95% confidence interval 1.57-4.06) and the overall effect z-score was 4.42 (P < 0.0001). The heterogeneity test revealed significant differences among individual studies (P = 0.000, I(2)  = 98.7%). Serum TNF-α levels were significantly increased in patients relative to those in controls. The heterogeneity could be attributed to the differences in the detection methods and sampling times used in the different studies.