Development of advanced high energy density lithium ion batteries is important for promoting electromobility. Making electric vehicles attractive and competitive compared to conventional automobiles ...depends on the availability of reliable, safe, high power, and highly energetic batteries whose components are abundant and cost effective. Nickel rich LiNi x Co y Mn 1−x−y O 2 layered cathode materials ( x > 0.5) are of interest because they can provide very high specific capacity without pushing charging potentials to levels that oxidize the electrolyte solutions. However, these cathode materials suffer from stability problems. We discovered that doping these materials with tungsten (1 mol%) remarkably increases their stability due to a partial layered to cubic (rock salt) phase transition. We demonstrate herein highly stable Li ion battery prototypes consisting of tungsten-stabilized Ni rich cathode materials ( x > 0.9) with specific capacities >220 mA h g -1 . This development can increase the energy density of Li ion batteries more than 30% above the state of the art without compromising durability.
Magnetic Weyl semimetal phase in a Kagomé crystal Liu, D F; Liang, A J; Liu, E K ...
Science (American Association for the Advancement of Science),
09/2019, Letnik:
365, Številka:
6459
Journal Article
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Weyl semimetals are crystalline solids that host emergent relativistic Weyl fermions and have characteristic surface Fermi-arcs in their electronic structure. Weyl semimetals with broken time ...reversal symmetry are difficult to identify unambiguously. In this work, using angle-resolved photoemission spectroscopy, we visualized the electronic structure of the ferromagnetic crystal Co
Sn
S
and discovered its characteristic surface Fermi-arcs and linear bulk band dispersions across the Weyl points. These results establish Co
Sn
S
as a magnetic Weyl semimetal that may serve as a platform for realizing phenomena such as chiral magnetic effects, unusually large anomalous Hall effect and quantum anomalous Hall effect.
This article provides a comprehensive review of current research activities that concentrate on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—whose lateral dimensions fall ...anywhere in the range of 1 to 100 nm. We devote the most attention to 1D nanostructures that have been synthesized in relatively copious quantities using chemical methods. We begin this article with an overview of synthetic strategies that have been exploited to achieve 1D growth. We then elaborate on these approaches in the following four sections: i) anisotropic growth dictated by the crystallographic structure of a solid material; ii) anisotropic growth confined and directed by various templates; iii) anisotropic growth kinetically controlled by supersaturation or through the use of an appropriate capping reagent; and iv) new concepts not yet fully demonstrated, but with long‐term potential in generating 1D nanostructures. Following is a discussion of techniques for generating various types of important heterostructured nanowires. By the end of this article, we highlight a range of unique properties (e.g., thermal, mechanical, electronic, optoelectronic, optical, nonlinear optical, and field emission) associated with different types of 1D nanostructures. We also briefly discuss a number of methods potentially useful for assembling 1D nanostructures into functional devices based on crossbar junctions, and complex architectures such as 2D and 3D periodic lattices. We conclude this review with personal perspectives on the directions towards which future research on this new class of nanostructured materials might be directed.
Current research activities concentrating on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—are comprehensively reviewed. Chemical methods of synthesis are introduced and a range of growth mechanisms discussed in terms of shape control. The generation of heterostructured nanowires is detailed, as is the range of unique properties of 1D nanostructures. The assembly of 1D nanostructures into functional devices is also mentioned. The article concludes with perspectives on future research and related issues.
We report on the experimental generation of relativistic electron bunches with a tunable longitudinal bunch shape. A longitudinal bunch-shaping (LBS) beam line, consisting of a transverse mask ...followed by a transverse-to-longitudinal emittance exchange (EEX) beam line, is used to tailor the longitudinal bunch shape (or current profile) of the electron bunch. The mask shapes the bunch's horizontal profile, and the EEX beam line converts it to a corresponding longitudinal profile. The Argonne wakefield accelerator rf photoinjector delivers electron bunches into a LBS beam line to generate a variety of longitudinal bunch shapes. The quality of the longitudinal bunch shape is limited by various perturbations in the exchange process. We develop a simple method, based on the incident slope of the bunch, to significantly suppress the perturbations.
Cancer metastasis requires that primary tumour cells evolve the capacity to intravasate into the lymphatic system or vasculature, and extravasate into and colonize secondary sites. Others have ...demonstrated that individual cells within complex populations show heterogeneity in their capacity to form secondary lesions. Here we develop a polyclonal mouse model of breast tumour heterogeneity, and show that distinct clones within a mixed population display specialization, for example, dominating the primary tumour, contributing to metastatic populations, or showing tropism for entering the lymphatic or vasculature systems. We correlate these stable properties to distinct gene expression profiles. Those clones that efficiently enter the vasculature express two secreted proteins, Serpine2 and Slpi, which were necessary and sufficient to program these cells for vascular mimicry. Our data indicate that these proteins not only drive the formation of extravascular networks but also ensure their perfusion by acting as anticoagulants. We propose that vascular mimicry drives the ability of some breast tumour cells to contribute to distant metastases while simultaneously satisfying a critical need of the primary tumour to be fed by the vasculature. Enforced expression of SERPINE2 and SLPI in human breast cancer cell lines also programmed them for vascular mimicry, and SERPINE2 and SLPI were overexpressed preferentially in human patients that had lung-metastatic relapse. Thus, these two secreted proteins, and the phenotype they promote, may be broadly relevant as drivers of metastatic progression in human cancer.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Well-ordered high crystalline LiNi0.5Mn1.5O4 spinel has been readily synthesized by a molten salt method using a mixture of LiCl and LiOH salts. Synthetic variables on the synthesis of ...LiNi0.5Mn1.5O4, such as synthetic atmosphere, LiCl salt amount, synthetic temperature, and synthetic time, were intensively investigated. X-ray diffraction (XRD) patterns and scanning electron microscopic (SEM) images showed that LiNi0.5Mn1.5O4 synthesized at 900 and 950 deg C have cubic spinel structure (Fd3m) with clear octahedral dimension. LiNi0.5Mn1.5O4 spinel phase began to decompose at around 1000'C accompanied with structural and morphological degradation. LiNi0.5Mn1.5O4 powders synthesized at 900'C for 3 h delivered an initial discharge capacity of 139 mAh/g with excellent capacity retention rate more than 99% after 50 cycles.
Glucagon contributes to liver zonation Cheng, Xiping; Kim, Sun Y.; Okamoto, Haruka ...
Proceedings of the National Academy of Sciences - PNAS,
04/2018, Letnik:
115, Številka:
17
Journal Article
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Liver zonation characterizes the separation of metabolic pathways along the lobules and is required for optimal function. Wnt/β-catenin signaling controls metabolic zonation by activating genes in ...the perivenous hepatocytes, while suppressing genes in the periportal counterparts. We now demonstrate that glucagon opposes the actions of Wnt/β-catenin signaling on gene expression and metabolic zonation pattern. The effects were more pronounced in the periportal hepatocytes where 28% of all genes were activated by glucagon and inhibited by Wnt/β-catenin. The glucagon and Wnt/β-catenin receptors and their signaling pathways are uniformly distributed in periportal and perivenous hepatocytes and the expression is not regulated by the opposing signal. Collectively, our results show that glucagon controls gene expression and metabolic zonation in the liver through a counterplay with the Wnt/β-catenin signaling pathway.
1‐palmitoyl‐2‐linoleoyl‐3‐acetyl‐rac‐glycerol (PLAG), a chemically synthesized monoacetyldiaglyceride, is one of the constituents in Sika deer antlers and has been known traditionally as having ...immunomodulatory effects. However, the mechanism by which PLAG controls neutrophil migration, which evokes liver injury in the hepatitis animal model, remains largely unknown. This study was designed to evaluate the immunomodulatory effects of PLAG on cytokine secretion and neutrophil migration in vivo and in vitro. Concanavalin A (Con A) induced leukocyte infiltration in the liver and increased plasma cytokine levels. Pretreatment with PLAG reduced the levels of interleukin (IL)‐4, IL‐6, IL‐10, and CXCL2, but maintained interferon (IFN)‐γ levels and modulated neutrophil recruitment toward the liver. Furthermore, the mRNA and protein levels of IL‐4 and CXCL2 in liver tissue were also decreased in the Con A‐treated mice. Liver histology analyses showed that PLAG reduced Con A‐induced hepatic necrosis, which was accompanied by leukocyte infiltration. The in vitro studies revealed that PLAG reduced IL‐4 secretion in Con A stimulated T cell and blocked signal transducer and activator of transcription 6 (STAT6) Con A induced hepatocyte. PLAG attenuated IL‐4 induced activation of atypical protein kinase C (PKC)/STAT6 in hepatocytes and inhibited neutrophil migration toward the liver tissue through suppression of IL‐8/vascular cell adhesion molecule (VCAM) expression. These results suggest that PLAG could mitigate excess neutrophil migration into liver tissue and potentially have a therapeutic effect on immune‐mediated liver injury.
Liver damage was evaluated by histological observation in PLAG‐treated mouse livers.The ability of PLAG to suppress the phosphorylation of the PKC‐ζ/STAT6 pathway resulted in inhibition of hepatic cytokine expression in the plasma, the expression of adhesion molecules, and neutrophil migration.
Al and/or Mg-substituted LiNi0.8Co0.1Mn0.1-x-yAlxMgyO2 were prepared by a co-precipitation method and characterized by X-ray diffraction with Rietveld refinement, thermogravimetric analysis, ...differential scanning calorimetry (DSC), and electrochemical measurements. The Rietveld refinement results show that cation mixing of Al and/or Mg-substituted LiNi0.8Co0.1Mn0.1-x-yAlxMgyO2 was reduced with increased doping amounts of Al and Mg. The Al and/or Mg substitution in LiNi0.8Co0.1Mn0.1O2 also resulted in improved electrochemical cycling behavior, structural stability, and thermal stability compared to pristine LiNi0.8Co0.1Mn0.1O2. The improvements of electrochemical and thermal properties resulted from the stabilized host structure by Al and/or Mg incorporation into LiNi0.8Co0.1Mn0.1O2.
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