Excited-state spectroscopy of spin defects in hexagonal boron nitride

We used optically detected magnetic resonance (ODMR) technique to directly probe electron-spin resonance transitions in the excited state of negatively-charged boron vacancy (VB-) defects in hexagonal boron nitride (hBN) at room temperature. The data showed that the excited state has a zero-field splitting of ~ 2.1 GHz, a g factor similar to the ground state and two types of hyperfine splitting ~ 90 MHz and ~ 18.8 MHz respectively. Pulsed ODMR experiments were conducted to further verify observed resonant peaks corresponding to spin transitions in the excited state. In addition, negative peaks in photoluminescence and ODMR contrast as a function of magnetic field magnitude and angle at level anti-crossing were observed and explained by coherent spin precession and anisotropic relaxation. This work provided significant insights for studying the structure of VB- excited states, which might be used for quantum information processing and nanoscale quantum sensing

Atypical radio pulsations from magnetar SGR 1935+2154

Magnetars are neutron stars with extremely strong magnetic fields, frequently powering high-energy activity in X-rays. Pulsed radio emission following some X-ray outbursts have been detected, albeit its physical origin is unclear. It has long been speculated that the origin of magnetars' radio signals is different from those from canonical pulsars, although convincing evidence is still lacking. Five months after magnetar SGR 1935+2154's X-ray outburst and its associated Fast Radio Burst (FRB) 20200428, a radio pulsar phase was discovered. Here we report the discovery of X-ray spectral hardening associated with the emergence of periodic radio pulsations from SGR 1935+2154 and a detailed analysis of the properties of the radio pulses. The complex radio pulse morphology, which contains both narrow-band emission and frequency drifts, has not been seen before in other magnetars, but is similar to those of repeating FRBs - even though the luminosities are many orders of magnitude different. The observations suggest that radio emission originates from the outer magnetosphere of the magnetar, and the surface heating due to the bombardment of inward-going particles from the radio emission region is responsible for the observed X-ray spectral hardening.Comment: 47 pages, 11 figure

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

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 .)

Probing Polymorphic Stacking Domains in Mechanically Exfoliated Two-Dimensional Nanosheets Using Atomic Force Microscopy and Ultralow-Frequency Raman Spectroscopy

As one of the key features of two-dimensional (2D) layered materials, stacking order has been found to play an important role in modulating the interlayer interactions of 2D materials, potentially affecting their electronic and other properties as a consequence. In this work, ultralow-frequency (ULF) Raman spectroscopy, electrostatic force microscopy (EFM), and high-resolution atomic force microscopy (HR-AFM) were used to systematically study the effect of stacking order on the interlayer interactions as well as electrostatic screening of few-layer polymorphic molybdenum disulfide (MoS2) and molybdenum diselenide (MoSe2) nanosheets. The stacking order difference was first confirmed by measuring the ULF Raman spectrum of the nanosheets with polymorphic stacking domains. The atomic lattice arrangement revealed using HR-AFM also clearly showed a stacking order difference. In addition, EFM phase imaging clearly presented the distribution of the stacking domains in the mechanically exfoliated nanosheets, which could have arisen from electrostatic screening. The results indicate that EFM in combination with ULF Raman spectroscopy could be a simple, fast, and high-resolution method for probing the distribution of polymorphic stacking domains in 2D transition metal dichalcogenide materials. Our work might be promising for correlating the interlayer interactions of TMDC nanosheets with stacking order, a topic of great interest with regard to modulating their optoelectronic properties

Defining Suitable Reference Genes for qRT-PCR in <i>Plagiodera versicolora</i> (Coleoptera: Chrysomelidae) under Different Biotic or Abiotic Conditions

Plagiodera versicolora (Coleoptera: Chrysomelidae) is one of the most destructive pests of the Salicaceae worldwide, which has established complex interactions with surrounding organisms. Uncovering the molecular mechanisms of some antagonistic interactions would facilitate the development of environmentally friendly pest insect management strategies. Suitable reference genes are essential for reliable qPCR and gene expression analysis in molecular studies; however, a comprehensive assessment of reference genes in P. versicolora is still lacking. In this study, the stability of seven housekeeping genes (including Actin, EF1A, α-tubulin, RPL13a, RPS18, RPL8 and UBC) was investigated under both biotic (developmental stages, tissues, sex and pathogen treatment) and abiotic (RNA interference treatment, temperature treatment) conditions. The geNorm, NormFinder, BestKeeper, and ΔCt programs were used to analyze gene expression data. The RefFinder synthesis analysis was applied to suggest a handful of appropriate reference genes for each experimental condition. RPS18 and EF1A were the most reliable reference genes in different development stages; RPS18 and RPL8 were most stable in female and male adults, different tissues, different temperatures, and pathogen treatment; α-tubulin and RPL13a were most stable after dietary RNAi treatment. The research provides a strong basis for future research into the molecular biology of P. versicolora

Defining Suitable Reference Genes for qRT-PCR in Plagiodera versicolora (Coleoptera: Chrysomelidae) under Different Biotic or Abiotic Conditions

Plagiodera versicolora (Coleoptera: Chrysomelidae) is one of the most destructive pests of the Salicaceae worldwide, which has established complex interactions with surrounding organisms. Uncovering the molecular mechanisms of some antagonistic interactions would facilitate the development of environmentally friendly pest insect management strategies. Suitable reference genes are essential for reliable qPCR and gene expression analysis in molecular studies; however, a comprehensive assessment of reference genes in P. versicolora is still lacking. In this study, the stability of seven housekeeping genes (including Actin, EF1A, &alpha;-tubulin, RPL13a, RPS18, RPL8 and UBC) was investigated under both biotic (developmental stages, tissues, sex and pathogen treatment) and abiotic (RNA interference treatment, temperature treatment) conditions. The geNorm, NormFinder, BestKeeper, and &Delta;Ct programs were used to analyze gene expression data. The RefFinder synthesis analysis was applied to suggest a handful of appropriate reference genes for each experimental condition. RPS18 and EF1A were the most reliable reference genes in different development stages; RPS18 and RPL8 were most stable in female and male adults, different tissues, different temperatures, and pathogen treatment; &alpha;-tubulin and RPL13a were most stable after dietary RNAi treatment. The research provides a strong basis for future research into the molecular biology of P. versicolora

LZTS1 promotes proliferation and suppresses apoptosis by inhibiting the activation of AKT/GSK-3 signaling pathway in pancreatic cancer cells

Purpose: Pancreatic cancer is a kind of harmful human cancer, rated as the seventh leading cause of global death. Research has shown that in various cancers, the expression of Leucine zipper tumor suppressor 1 (LZTS1) has been found low, but its effects on pancreatic cancer is yet to be elucidated. In this research, the aim was to investigate the biological functions of LZTS1 and the underlying molecular mechanism in pancreatic cancer. Methods: GEPIA database was reported for the relative expression of LZTS1 in pancreatic cancer tissues and cell lines compared to normal ones. Kaplan-Meier analysis was done on GEPIA based on the previous data. Gene expression analysis was performed on human pancreatic cancer cell lines (BXPC3, CFPC-1, Panc-1, AsPC-1 and L3.6pl) as well as a normal cell line HEK-293T by employing RT-qPCR. Transfection procedure was done to up- or down-regulate the expressions of LZTS1 in Panc1 cell line. CCK-8 assay and flow cytometric method were adopted to determine cell viability and apoptosis, respectively. Protein expression levels were determined by Western blot. Results: Expressions of LZTS1 were high in both tumor tissues and cells. Patients with higher LZTS1 had lower 5-year overall survival rate compared to those with lower LZTS1. Overexpressed LZTS1 promoted proliferation and inhibited apoptosis in cancer cell lines. A significant promotion of phosphorylated level of AKT and GSK-3 proteins were achieved through the overexpression of LZTS1. Conclusion: The results from this study revealed that overexpression of LZTS1 increased cell viability and inhibited cell apoptosis, by activation of AKT/GSK-3 signaling pathway. Our findings indicated that LZTS1 might be a prognostic biomarker in pancreatic cancer

Contribution of Urine and Dung Patches from Grazing Sheep to Methane and Carbon Dioxide Fluxes in an Inner Mongolian Desert Grassland

The effects of sheep urine and dung patches on methane (CH4) and carbon dioxide (CO2) fluxes were investigated during the summer-autumn in 2010, to evaluate their contribution to climate change in a desert grassland in Inner Mongolia, China. Results indicate that the cumulative CH4 emissions for dung patches, urine patches and control plots were − −0.076, −0.084, and −0.114 g/m2 and these were net CH4 sinks during the measured period. The level of CH4 intake from urine and dung plots decreased 25.7%, and 33.3%, respectively, compared with a control plot. CO2 fluxes differed (p<0.01) in urine plots, with an average of 569.20 mg/m2/h compared with control plots (357.62 mg/m2/h) across all sampling days. Dung patches have cumulative CO2 emissions that were 15.9% higher compared with the control during the 55-d period. Overall, sheep excrement weakened CH4 intake and increased CO2 emissions