79 research outputs found
High Reversibility of Lattice Oxygen Redox in Na-ion and Li-ion Batteries Quantified by Direct Bulk Probes of both Anionic and Cationic Redox Reactions
The reversibility and cyclability of anionic redox in battery electrodes hold
the key to its practical employments. Here, through mapping of resonant
inelastic X-ray scattering (mRIXS), we have independently quantified the
evolving redox states of both cations and anions in Na2/3Mg1/3Mn2/3O2. The
bulk-Mn redox emerges from initial discharge and is quantified by
inverse-partial fluorescence yield (iPFY) from Mn-L mRIXS. Bulk and surface Mn
activities likely lead to the voltage fade. O-K super-partial fluorescence
yield (sPFY) analysis of mRIXS shows 79% lattice oxygen-redox reversibility
during initial cycle, with 87% capacity sustained after 100 cycles. In
Li1.17Ni0.21Co0.08Mn0.54O2, lattice-oxygen redox is 76% initial-cycle
reversible but with only 44% capacity retention after 500 cycles. These results
unambiguously show the high reversibility of lattice-oxygen redox in both
Li-ion and Na-ion systems. The contrast between Na2/3Mg1/3Mn2/3O2 and
Li1.17Ni0.21Co0.08Mn0.54O2 systems suggests the importance of distinguishing
lattice-oxygen redox from other oxygen activities for clarifying its intrinsic
properties.Comment: 33 pages, 8 Figures. Plus 14 pages of Supplementary Materials with 12
Figure
New genetic loci link adipose and insulin biology to body fat distribution.
Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
Familial Autoimmune Thyroid Disease as a Risk Factor for Regression in Children with Autism Spectrum Disorder: A CPEA Study
A multicenter study of 308 children with Autism Spectrum Disorder (ASD) was conducted through the Collaborative Programs of Excellence in Autism (CPEA), sponsored by the National Institute of Child Health and Human Development, to compare the family history of autoimmune disorders in children with ASD with and without a history of regression. A history of regression was determined from the results of the Autism Diagnostic Interview-Revised (ADI-R). Family history of autoimmune disorders was obtained by telephone interview. Regression was significantly associated with a family history of autoimmune disorders (adjusted OR=1.89; 95% CI: 1.17, 3.10). The only specific autoimmune disorder found to be associated with regression was autoimmune thyroid disease (adjusted OR=2.09; 95% CI: 1.28, 3.41).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43035/1/10803_2005_Article_71.pd
The Materials Research Platform: Defining the Requirements from User Stories
A recent meeting focused on accelerated materials design and discovery examined user requirements for a general, collaborative, integrative, and on-demand materials research platform
Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease
BACKGROUND:
Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes.
METHODS:
We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization.
RESULTS:
During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events.
CONCLUSIONS:
Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)
Calcination Heterogeneity in Li-rich Layered Oxides: a Systematic Study of Li2CO3 Particle Size
Li- and Mn-rich (LMR) layered oxide positive electrode materials exhibit high energy density and have earth abundant compositions relative to conventional Ni-, Mn-, and Co-oxides (NMCs). The lithiation of coprecipitated precursors is a key part of synthesis and offers opportunities for tuning the properties of LMR materials. Whereas the morphology of transition metal precursors has received substantial attention, that of Li sources has not. Using Li1.14Mn0.57Ni0.29O2 as a model system, in this work we establish a detailed understanding of LMR calcination pathways via in situ and ex situ diffraction, spectroscopy, microscopy and thermogravimetry. Our work shows that large Li2CO3 particle size modulates a previously misunderstood thermogravimetric feature present at the Li2CO3 melting point during layered oxide calcination and causes heterogeneity at larger length scales (inter-secondary particle) than previously reported (intra secondary particle). This work highlights the sensitivity of layered oxide calcination pathways to synthesis conditions and suggests design rules to minimize calcination heterogeneity in layered oxides beyond LMR
Effects of Particle Size, Electronic Connectivity, and Incoherent Nanoscale Domains on the Sequence of Lithiation in LiFePO₄ Porous Electrodes.
High-resolution X-ray microscopy is used to investigate the sequence of lithiation in LiFePO4 porous electrodes. For electrodes with homogeneous interparticle electronic connectivity via the carbon black network, the smaller particles lithiate first. For electrodes with heterogeneous connectivity, the better-connected particles preferentially lithiate. Correlative electron and X-ray microscopy also reveal the presence of incoherent nanodomains that lithiate as if they are separate particles
Recommended from our members
Electrode Lithiation: Effects of Particle Size, Electronic Connectivity, and Incoherent Nanoscale Domains on the Sequence of Lithiation in LiFePO4Porous Electrodes (Adv. Mater. 42/2015)
- …