3,857 research outputs found
Synergistic multi-doping effects on the Li7La3Zr2O12 solid electrolyte for fast lithium ion conduction.
Here, we investigate the doping effects on the lithium ion transport behavior in garnet Li7La3Zr2O12 (LLZO) from the combined experimental and theoretical approach. The concentration of Li ion vacancy generated by the inclusion of aliovalent dopants such as Al(3+) plays a key role in stabilizing the cubic LLZO. However, it is found that the site preference of Al in 24d position hinders the three dimensionally connected Li ion movement when heavily doped according to the structural refinement and the DFT calculations. In this report, we demonstrate that the multi-doping using additional Ta dopants into the Al-doped LLZO shifts the most energetically favorable sites of Al in the crystal structure from 24d to 96 h Li site, thereby providing more open space for Li ion transport. As a result of these synergistic effects, the multi-doped LLZO shows about three times higher ionic conductivity of 6.14 × 10(-4) S cm(-1) than that of the singly-doped LLZO with a much less efforts in stabilizing cubic phases in the synthetic condition
High-Throughput Screening of Acyl-CoA Thioesterase I Mutants Using a Fluid Array Platform
Screening target microorganisms from a mutated recombinant library plays a crucial role in advancing synthetic biology and metabolic engineering. However, conventional screening tools have several limitations regarding throughput, cost, and labor. Here, we used the fluid array platform to conduct high-throughput screening (HTS) that identified Escherichia coli ???TesA thioesterase mutants producing elevated yields of free fatty acids (FFAs) from a large (106) mutant library. A growth-based screening method using a TetA-RFP fusion sensing mechanism and a reporter-based screening method using high-level FFA producing mutants were employed to identify these mutants via HTS. The platform was able to cover >95% of the mutation library, and it screened target cells from many arrays of the fluid array platform so that a post-analysis could be conducted by gas chromatography. The ???TesA mutation of each isolated mutant showing improved FFA production in E. coli was characterized, and its enhanced FFA production capability was confirmed
Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk
We present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity
halo-like main-sequence (MS) stars, which has been referred to as the Splash or
Splashed Disk, selected from Sloan Digital Sky Survey (SDSS) and Large Sky Area
Multi-Object Fiber Spectroscopic Telescope (LAMOST). When divided into two
groups, a low-[/Fe] population (LAP) and a high-[/Fe]
population (HAP), based on kinematics and chemistry, we find that they exhibit
very distinct properties, indicative of different origins. From a detailed
analysis of their orbital inclinations, we suggest that the HAP arises from a
large fraction (~ 90%) of heated disk stars and a small fraction (~ 10%) of in
situ stars from a starburst population, likely induced by interaction of the
Milky Way with Gaia Sausage/Enceladus (GSE) or other early merger. The LAP
comprises about half accreted stars from the GSE and half formed by the
GSE-induced starburst. Our findings further imply that the Splash stars in our
sample originated from at least three different mechanisms - accretion, disk
heating, and a merger induced starburst
Improved Regret Bounds of (Multinomial) Logistic Bandits via Regret-to-Confidence-Set Conversion
Logistic bandit is a ubiquitous framework of modeling users' choices, e.g.,
click vs. no click for advertisement recommender system. We observe that the
prior works overlook or neglect dependencies in , where is the unknown parameter
vector, which is particularly problematic when is large, e.g., .
In this work, we improve the dependency on via a novel approach called {\it
regret-to-confidence set conversion (R2CS)}, which allows us to construct a
convex confidence set based on only the \textit{existence} of an online
learning algorithm with a regret guarantee. Using R2CS, we obtain a strict
improvement in the regret bound w.r.t. in logistic bandits while retaining
computational feasibility and the dependence on other factors such as and
. We apply our new confidence set to the regret analyses of logistic bandits
with a new martingale concentration step that circumvents an additional factor
of . We then extend this analysis to multinomial logistic bandits and obtain
similar improvements in the regret, showing the efficacy of R2CS. While we
applied R2CS to the (multinomial) logistic model, R2CS is a generic approach
for developing confidence sets that can be used for various models, which can
be of independent interest.Comment: 32 pages, 2 figures, 1 tabl
Effect of Long-Term Dietary Arginyl-Fructose (AF) on Hyperglycemia and HbA1c in Diabetic db/db Mice
We have previously reported that Amadori compounds exert anti-diabetic effects by lowering sucrose-induced hyperglycemia in normal Sprague-Dawley rats. In the present study we extended our recent findings to evaluate whether α-glucosidase inhibitor arginyl-fructose (AF) lowers blood glucose level in diabetic db/db mice, a genetic model for type 2 diabetes. The db/db mice were randomly assigned to high-carbohydrate diets (66.1% corn starch) with and without AF (4% in the diet) for 6 weeks. Changes in body weight, blood glucose level, and food intake were measured daily for 42 days. Dietary supplementation of AF resulted in a significant decrease of blood glucose level (p \u3c 0.001) and body weight (p \u3c 0.001). The level of HbA1c, a better indicator of plasma glucose concentration over prolonged periods of time, was also significantly decreased for 6-week period (p \u3c 0.001). Dietary treatment of acarbose® (0.04% in diet), a positive control, also significantly alleviated the level of blood glucose, HbA1c, and body weight. These results indicate that AF Maillard reaction product improves postprandial hyperglycemia by suppressing glucose absorption as well as decreasing HbA1c level
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