Disordered structure for long-range charge density wave order in annealed crystals of magnetic kagome FeGe

Recently, charge density wave (CDW) has been observed well below the order of antiferromagnetism (AFM) in kagome FeGe in which magnetism and CDW are intertwined to form an emergent quantum ground state. The mechanism of CDW precipitating from an A-type AFM of Fe kagome sublattice is intensively debated. The structural distortion originating from the CDW has yet to be accurately determined in FeGe. Here we resolved the structure model of the CDW in annealed FeGe crystals through single crystal x-ray diffraction via a synchrotron radiation source. The annealed crystals exhibit strong CDW transition signals exemplified by sharp magnetic susceptibility drop and specific heat jump, as well as intense superlattice reflections from 2 $\times$ 2 $\times$ 2 CDW order. Occupational disorder of Ge atoms resulting from short-range CDW correlations above $T_\mathrm{CDW}$ has also been identified from the structure refinements. The dimerization of Ge atoms along c axis has been demonstrated to be the dominant distortion for CDW. The Fe kagome and Ge honeycomb sublattices only undergo subtle distortions. Occupational disorder of Ge atoms is also proved to exist in the CDW phase due to the random selection of partial Ge sites to be dimerized to realize the structural distortion. Our work paves the way to understanding the unconventional nature of CDW in FeGe not only by solving the structural distortion below $T_\mathrm{CDW}$ and identifying fluctuations above it but also by rationalizing the synthesis of high-quality crystals for in-depth investigations in the future.Comment: 18 pages, 4 figures. Comments are welcom

Metabolomics in the Development and Progression of Dementia: A Systematic Review

Dementia has become a major global public health challenge with a heavy economic burden. It is urgently necessary to understand dementia pathogenesis and to identify biomarkers predicting risk of dementia in the preclinical stage for prevention, monitoring, and treatment. Metabolomics provides a novel approach for the identification of biomarkers of dementia. This systematic review aimed to examine and summarize recent retrospective cohort human studies assessing circulating metabolite markers, detected using high-throughput metabolomics, in the context of disease progression to dementia, including incident mild cognitive impairment, all-cause dementia, and cognitive decline. We systematically searched the PubMed, Embase, and Cochrane databases for retrospective cohort human studies assessing associations between blood (plasma or serum) metabolomics profile and cognitive decline and risk of dementia from inception through October 15, 2018. We identified 16 studies reporting circulating metabolites and risk of dementia, and six regarding cognitive performance change. Concentrations of several blood metabolites, including lipids (higher phosphatidylcholines, sphingomyelins, and lysophophatidylcholine, and lower docosahexaenoic acid and high-density lipoprotein subfractions), amino acids (lower branched-chain amino acids, creatinine, and taurine, and higher glutamate, glutamine, and anthranilic acid), and steroids were associated with cognitive decline and the incidence or progression of dementia. Circulating metabolites appear to be associated with the risk of dementia. Metabolomics could be a promising tool in dementia biomarker discovery. However, standardization and consensus guidelines for study design and analytical techniques require future development

Geographic and temporal trends in the molecular epidemiology and genetic mechanisms of transmitted HIV-1 drug resistance:an individual-patient- and sequence-level meta-analysis

Regional and subtype-specific mutational patterns of HIV-1 transmitted drug resistance (TDR) are essential for informing first-line antiretroviral (ARV) therapy guidelines and designing diagnostic assays for use in regions where standard genotypic resistance testing is not affordable. We sought to understand the molecular epidemiology of TDR and to identify the HIV-1 drug-resistance mutations responsible for TDR in different regions and virus subtypes.status: publishe

Characteristics of Electromagnetic Coupling with A Wire through Shielding Enclosure

The paper presents a numerical method based on Finite Difference Time Domain (FDTD) in both frequency and time domain for modeling the coupling of an incident electromagnetic pulse(EMP) with a conducting wire through a metallic shielding enclosure with a small aperture. Simulation and analysis are done by radius, length, and number of the wires, the incidence angle of EMP and the polaration angle of electric field in consideration. The simulation result shows that interference of the electromagnetic coupling into the shielding enclosure can be affected in different degrees by above factors. At low frequency, the larger the leakage length, the radius or the number of the wire penetrated into the cavity, the more interference is coupled into the shielding cavity from electromagnetic field. Also, the smaller the incident direction angle of propagation of the electromagnetic pulse or the polarization direction angle of the incident electric field, the more easily the electromagnetic interference is coupled into the cavity. DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.398

Cross Validation Based Distributed Greedy Sparse Recovery for Multiview Through-the-Wall Radar Imaging

Multiview through-the-wall radar imaging (TWRI) can improve the imaging quality and target detection by exploiting the measurement data acquired from various views. Based on the established joint sparsity signal model for multiview TWRI, a cross validation (CV) based distributed greedy sparse recovery algorithm which combines the strengths of the CV technique and censored simultaneous orthogonal matching pursuit algorithm (CSOMP) is proposed in this paper. The developed imaging algorithm named by CV-CSOMP which separates the total measurements into reconstruction measurements and CV measurements is able to achieve the accurate imaging reconstruction and estimation of recovery error tolerance by the iterative CSOMP calculation. The proposed CV-CSOMP imaging algorithm not only can reduce the communication costs among radar units, but also can provide the desirable imaging performance without the prior information such as the sparsity or noise level. The experimental results have verified the validity and effectiveness of the proposed imaging algorithm

Alterations of bile acids and gut microbiota in obesity induced by high fat diet in rat model

Obesity has become a worldwide health issue and has attracted much public attention. In the current study, we aim to elucidate the roles of bile acids and their associations with gut microbiota during obesity development, employing high fat diet (HFD)-induced obesity in a rat model. We collected feces and plasma, liver tissues, and segments of intestinal tissues and a developed bile acids quantification method by employing an ultraperformance liquid chromatography coupled with mass spectrometry detection (UPLC-MS) strategy. We then assessed bile acids fluxes in the biological matrixes collected. We found that, irrespective of dietary regimes, taurine-conjugated bile acids were the dominant species in the liver whereas unconjugated bile acids were in plasma. However, HFD caused slight increases in the total bile acids pool and particularly the increases in the levels of deoxycholic acid (DCA) (138.67 ± 37.225 nmol/L in control group, 242.61 ± 43.16 nmol/L in HFD group, p = 0.014) and taurodeoxycholic acid (TDCA) (2.8 ± 0.247 nmol/g in control group, 4.5 ± 0.386 nmol/g in HFD group, p = 0.0018) in plasma and liver tissues, respectively, which were consistent with the increased levels of DCA in intestinal tissues and feces. These changes are correlated to an increase in abundance of genera Blautia, Coprococcus, Intestinimonas, Lactococcus, Roseburia, and Ruminococcus. Our investigation revealed the fluxes of bile acids and their association with gut microbiota during obesity development and explicated unfavorable impact of HFD on health.Accepted versio