Spin-valley locking is ubiquitous among transition metal dichalcogenides with local or global inversion asymmetry, in turn stabilizing properties such as Ising superconductivity, and opening routes ...towards 'valleytronics'. The underlying valley-spin splitting is set by spin-orbit coupling but can be tuned via the application of external magnetic fields or through proximity coupling. However, only modest changes have been realized to date. Here, we investigate the electronic structure of the V-intercalated transition metal dichalcogenide V
NbS
using microscopic-area spatially resolved and angle-resolved photoemission spectroscopy. Our measurements and corresponding density functional theory calculations reveal that the bulk magnetic order induces a giant valley-selective Ising coupling exceeding 50 meV in the surface NbS
layer, equivalent to application of a ~250 T magnetic field. This energy scale is of comparable magnitude to the intrinsic spin-orbit splittings, and indicates how coupling of local magnetic moments to itinerant states of a transition metal dichalcogenide monolayer provides a powerful route to controlling their valley-spin splittings.
Previous studies have shown that omega-3 polyunsaturated fatty acids such as α-linolenic acid and docosahexaenoic acid (DHA) are neuroprotective in models of spinal cord injury (SCI) in rodents. ...However, the mechanism of action underlying these effects has not been elucidated, and the optimum treatment regime remains to be defined. We have therefore carried out a detailed analysis of the effects of DHA in adult rats subject to thoracic compression SCI. Saline or DHA (250 nmol/kg) was administered intravenously (i.v.) 30 min after compression. After injury, the saline group received a standard control diet for 1 or 6 weeks, whereas DHA-injected animals received either a control or a DHA-enriched diet (400 mg/kg/day) for 1 or 6 weeks. Other groups received a DHA-enriched diet only for 1 week following injury, or received acute DHA (250 nmol/kg; i.v.) treatment delayed up to 3 h after injury. We also assessed oxidative stress and the inflammatory reaction at the injury site, neuronal and oligodendrocyte survival and axonal damage and the locomotor recovery. At 24 h, lipid peroxidation, protein oxidation, RNA/DNA oxidation and the induction of cyclooxygenase-2 were all significantly reduced by i.v. DHA administration. At 1 week and 6 weeks, macrophage recruitment was reduced and neuronal and oligodendrocyte survival was substantially increased. Axonal injury was reduced at 6 weeks. Locomotor recovery was improved from day 4, and sustained up to 6 weeks. Rats treated with a DHA-enriched diet in addition to the acute DHA injection were not significantly different from the acute DHA-treated animals at 1 week, but at 6 weeks showed additional improvements in both functional and histological outcomes. DHA treatment was ineffective if the acute injection was delayed until 3 h post-injury, or if the DHA was administered for 1 week solely by diet. Our results in a clinically relevant model of SCI show that significant neuroprotection can be obtained by combining an initial acute i.v. injection of DHA with a sustained dietary supplementation. Given that the safety and tolerability of preparations enriched in omega-3 fatty acids is already well-documented, such a combined DHA treatment regime deserves consideration as a very promising approach to SCI management.
The oral streptococci are spherical Gram-positive bacteria categorized under the phylum Firmicutes which are among the most common causative agents of bacterial infective endocarditis (IE) and are ...also important agents in septicaemia in neutropenic patients. The Streptococcus mitis group is comprised of 13 species including some of the most common human oral colonizers such as S. mitis, S. oralis, S. sanguinis and S. gordonii as well as species such as S. tigurinus, S. oligofermentans and S. australis that have only recently been classified and are poorly understood at present. We present StreptoBase, which provides a specialized free resource focusing on the genomic analyses of oral species from the mitis group. It currently hosts 104 S. mitis group genomes including 27 novel mitis group strains that we sequenced using the high throughput Illumina HiSeq technology platform, and provides a comprehensive set of genome sequences for analyses, particularly comparative analyses and visualization of both cross-species and cross-strain characteristics of S. mitis group bacteria. StreptoBase incorporates sophisticated in-house designed bioinformatics web tools such as Pairwise Genome Comparison (PGC) tool and Pathogenomic Profiling Tool (PathoProT), which facilitate comparative pathogenomics analysis of Streptococcus strains. Examples are provided to demonstrate how StreptoBase can be employed to compare genome structure of different S. mitis group bacteria and putative virulence genes profile across multiple streptococcal strains. In conclusion, StreptoBase offers access to a range of streptococci genomic resources as well as analysis tools and will be an invaluable platform to accelerate research in streptococci. Database URL: http://streptococcus.um.edu.my.
The potassium graphite reduction of R‘BBr3 (R‘ = :C{N(2,4,6-Me3C6H2)CH}2) in Et2O led to the isolation of 3 (R‘(H)BB(H)R‘) and 4 (R‘(H)2B−B(H)2R‘), with BB double and B−B single bonds, ...respectively. These compounds were characterized by single-crystal X-ray diffraction, 1H and 11B NMR, and elemental analyses. Neutral diborene 3 exhibits polymorphic planar (3a), twisted (3b), and trans-bent (3c) geometries in the solid state.
Carbene-Stabilized Diphosphorus Wang, Yuzhong; Xie, Yaoming; Wei, Pingrong ...
Journal of the American Chemical Society,
11/2008, Letnik:
130, Številka:
45
Journal Article
Recenzirano
The potassium graphite reduction of L:PCl3 leads to the formation of carbene-stabilized diphosphorus molecules, L:P−P:L, 1 (L: = :C{N(2,6-Pr i 2C6H3)CH}2) and 2 (L: = :C{N(2,4,6-Me3C6H2)CH}2), ...respectively. The nature of the bonding in 1 and 2 was delineated by DFT computations.
The syntheses and molecular structures of four compounds are reported: 1 (RBBr3), 2 (R(H)2B−B(H)2R), 3 (R(H)BB(H)R), and 4 (RBH3) (R = :C{N(2,6-Pr i 2C6H3)CH}2). These compounds were characterized ...by single-crystal X-ray diffraction, 1H and 11B NMR, and elemental analyses. Compounds 2 and 3 were prepared by the KC8 reduction of 1 in Et2O. Compound 3 is the first structurally characterized neutral diborene (mean BB: 1.560(18) Å). The nature of the BB double bond in 3 was delineated by DFT computations.
Lake trophic state is a key ecosystem property that integrates a lake's physical, chemical, and biological processes. Despite the importance of trophic state as a gauge of lake water quality, ...standardized and machine-readable observations are uncommon. Remote sensing presents an opportunity to detect and analyze lake trophic state with reproducible, robust methods across time and space. We used Landsat surface reflectance data to create the first compendium of annual lake trophic state for 55,662 lakes of at least 10 ha in area throughout the contiguous United States from 1984 through 2020. The dataset was constructed with FAIR data principles (Findable, Accessible, Interoperable, and Reproducible) in mind, where data are publicly available, relational keys from parent datasets are retained, and all data wrangling and modeling routines are scripted for future reuse. Together, this resource offers critical data to address basic and applied research questions about lake water quality at a suite of spatial and temporal scales.
Summary
The study of glacial isostatic adjustment (GIA) is gaining an increasingly important role within the geophysical community. Understanding the response of the Earth to loading is crucial in ...various contexts, ranging from the interpretation of modern satellite geodetic measurements (e.g. GRACE and GOCE) to the projections of future sea level trends in response to climate change. Modern modelling approaches to GIA are based on various techniques that range from purely analytical formulations to fully numerical methods. Despite various teams independently investigating GIA, we do not have a suitably large set of agreed numerical results through which the methods may be validated; a community benchmark data set would clearly be valuable. Following the example of the mantle convection community, here we present, for the first time, the results of a benchmark study of codes designed to model GIA. This has taken place within a collaboration facilitated through European Cooperation in Science and Technology (COST) Action ES0701. The approaches benchmarked are based on significantly different codes and different techniques. The test computations are based on models with spherical symmetry and Maxwell rheology and include inputs from different methods and solution techniques: viscoelastic normal modes, spectral-finite elements and finite elements. The tests involve the loading and tidal Love numbers and their relaxation spectra, the deformation and gravity variations driven by surface loads characterized by simple geometry and time history and the rotational fluctuations in response to glacial unloading. In spite of the significant differences in the numerical methods employed, the test computations show a satisfactory agreement between the results provided by the participants.
Quantitative differences in biomarker expression relative to age and molecular subtypes have not been well documented in invasive breast cancer (IBCA).
Oestrogen receptor (ER), progesterone receptor ...(PR), HER2, ki67, p53 and DNA ploidy was performed by image analysis in 162 consecutive IBCAs in women (≤ 40 years) and compared with women ≥ 50 years (100 cases). Molecular subtypes were defined by immunohistochemistry (IHC).
Among young women, tumours were frequently ER negative (P=0.01) with lower ER (P<0.00), PR (P=0.03), higher ki67 index (KI) (P=0.01) and p53 (P=0.00) compared with older women. Triple negative was more frequent among young women with frequent lymph node involvement compared with older women. Luminal B among young vs old women showed lower ER (67% vs 88%), PR (32% vs 52%), higher KI (48% vs 34%) and p53 (19% vs 7%). Linear regression model showed increasing KI (P<0.0001) and p53 (P=0.0003) according to the molecular subtypes. Survival difference among subtypes was demonstrated by multivariate analysis (P=0.0092) after adjusting for age, race, tumour size, grade and stage.
We demonstrated significant differences in biomarker expression relative to age and molecular subtypes. Molecular subtype defined by IHC was an independent prognostic factor.
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