Abstract
We present the second release of value-added catalogues of the LAMOST Spectroscopic Survey of the Galactic Anticentre (LSS-GAC DR2). The catalogues present values of radial velocity Vr, ...atmospheric parameters – effective temperature Teff, surface gravity log g, metallicity Fe/H, α-element to iron (metal) abundance ratio α/Fe (α/M), elemental abundances C/H and N/H and absolute magnitudes MV and $M_{K_{\rm s}}$ deduced from 1.8 million spectra of 1.4 million unique stars targeted by the LSS-GAC since 2011 September until 2014 June. The catalogues also give values of interstellar reddening, distance and orbital parameters determined with a variety of techniques, as well as proper motions and multiband photometry from the far-UV to the mid-IR collected from the literature and various surveys. Accuracies of radial velocities reach 5 km s−1 for the late-type stars, and those of distance estimates range between 10 and 30 per cent, depending on the spectral signal-to-noise ratios. Precisions of Fe/H, C/H and N/H estimates reach 0.1 dex, and those of α/Fe and α/M reach 0.05 dex. The large number of stars, the contiguous sky coverage, the simple yet non-trivial target selection function and the robust estimates of stellar radial velocities and atmospheric parameters, distances and elemental abundances make the catalogues a valuable data set to study the structure and evolution of the Galaxy, especially the solar-neighbourhood and the outer disc.
As a major component of the LAMOST Galactic surveys, the LAMOST Spectroscopic Survey of the Galactic Anticentre (LSS-GAC) aims to survey a significant volume of the Galactic thin/thick discs and halo ...for a contiguous sky area of over 3400 deg2 centred on the Galactic anticentre (|b| ≤ 30°, 150 ≤ l ≤ 210°), and obtain λλ3700–9000 low-resolution (R ∼ 1800) spectra for a statistically complete sample of ∼3 M stars of all colours down to a limiting magnitude of r ∼ 17.8 mag (to 18.5 mag for limited fields). Together with Gaia, the LSS-GAC will yield a unique data set to advance our understanding of the structure and assemblage history of the Galaxy, in particular its disc(s). In addition to the main survey, the LSS-GAC will also target hundreds of thousands objects in the vicinity fields of M 31 and M 33 and survey a significant fraction (over a million) of randomly selected very bright stars (r ≤ 14 mag) in the Northern hemisphere. During the Pilot and the first year Regular Surveys of LAMOST, a total of 1042 586 750 867 spectra of a signal-to-noise ratio S/N(7450 Å) ≥ 10 S/N(4650 Å) ≥ 10 have been collected. In this paper, we present a detailed description of the target selection algorithm, survey design, observations and the first data release of value-added catalogues (including radial velocities, effective temperatures, surface gravities, metallicities, values of interstellar extinction, distances, proper motions and orbital parameters) of the LSS-GAC.
ABSTRACT
High time resolution and accuracy are of critical importance in the studies of timing analysis and time delay localization of gamma-ray bursts (GRBs), soft gamma-ray repeaters (SGRs) and ...pulsars. The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) consisting of two micro-satellites, GECAM-A and GECAM-B, launched on 2020 December 10, is aimed at monitoring and locating X-ray and GRBs all over the sky. To achieve its scientific goals, GECAM is designed to have the highest time resolution (0.1 $\mu {\rm s}$) among all GRB detectors ever flown. Here, we make a comprehensive time calibration campaign including both on-ground and on-orbit tests to derive not only the relative time accuracy of GECAM satellites and detectors, but also the absolute time accuracy of GECAM-B. Using the on-ground calibration with a $\rm ^{22}Na$ radioactive source, we find that the relative time accuracy between GECAM-A and GECAM-B is about 0.15 $\mu {\rm s}$ (1σ). To measure the relative time accuracy between all detectors of a single GECAM satellite, cosmic-ray events detected on orbit are utilized since they could produce many secondary particles simultaneously record by multiple detectors. We find that the relative time accuracy among all detectors onboard GECAM-B is about 0.12 $\mu {\rm s}$ (1σ). Finally, we use the novel Li-CCF method to perform the absolute time calibration with Crab pulsar and SGR J1935+2154, both of which were jointly observed by GECAM-B and Fermi/GBM, and obtain that the time difference between GECAM-B and Fermi/GBM is 3.06 ± 6.04 $\mu {\rm s}$ (1σ).
Cancer stem cells (CSCs) are inherently resistant to chemotherapy, and CSCs in chemotherapy-failed recurrent tumors are enriched; however, the cellular origin of chemotherapy-induced CSC enrichment ...remains unclear. Communication with stromal fibroblasts may induce cancer cell dedifferentiation into CSCs through secreted factors. We recently demonstrated that fibroblast-derived exosomes promote chemoresistance in colorectal cancer (CRC). Here, we report that fibroblasts confer CRC chemoresistance via exosome-induced reprogramming (dedifferentiation) of bulk CRC cells to phenotypic and functional CSCs. At the molecular level, we provided evidence that the major reprogramming regulators in fibroblast-exosomes are Wnts. Exosomal Wnts were found to increase Wnt activity and drug resistance in differentiated CRC cells, and inhibiting Wnt release diminished this effect in vitro and in vivo. Together, our results indicate that exosomal Wnts derived from fibroblasts could induce the dedifferentiation of cancer cells to promote chemoresistance in CRC, and suggest that interfering with exosomal Wnt signaling may help to improve chemosensitivity and the therapeutic window.
Because cerebral morphological abnormalities in major depressive disorder (MDD) may be modulated by antidepressant treatment, inclusion of medicated patients may have biased previous meta-analyses of ...voxel-based morphometry (VBM) studies. A meta-analysis of VBM studies on medication-free MDD patients should be able to distinguish the morphological features of the disease itself from those of treatment.
A systematic search was conducted for the relevant studies. Effect-size signed differential mapping was applied to analyse the grey matter differences between all medication-free MDD patients and healthy controls. Meta-regression was used to explore the effects of demographics and clinical characteristics.
A total of 14 datasets comprising 400 medication-free MDD patients and 424 healthy controls met the inclusion criteria. The pooled meta-analysis and subgroup meta-analyses showed robustly reduced grey matter in prefrontal and limbic regions in MDD. Increased right thalamus volume was only seen in first-episode medication-naive patients, and increased grey matter in the bilateral anterior cingulate cortex only in medication wash-out patients. In meta-regression analyses the percentage of female patients in each study was negatively correlated with reduced grey matter in the right hippocampus.
By excluding interference from medication effects, the present study identified grey matter reduction in the prefrontal-limbic network in MDD. The subgroup meta-analysis results suggest that an increased right thalamus volume might be a trait directly related to MDD, while an increased anterior cingulate cortex volume might be an effect of medication. The meta-regression results perhaps reveal the structural underpinning of the sex differences in epidemiological and clinical aspects of MDD.
Magnetic cellulose/Fe₃O₄/activated carbon composites (m-Cell/Fe₃O₄/ACCs) were prepared successfully and characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric ...analysis (TGA), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The adsorption of congo red onto the novel m-Cell/Fe₃O₄/ACCs was studied as a function of contact time, initial concentration of congo red, adsorbent dosage, and pH of solution. The saturated magnetization of m-Cell/Fe₃O₄/ACCs reached 48.2emug⁻¹ and the magnetic adsorbent showed characteristics of superparamagnetism, which indicated that m-Cell/Fe₃O₄/ACCs could be separated from treated solution by a magnetic process. A comparison of kinetic models showed that the overall adsorption process was best described by pseudo-second-order kinetic model. Thermodynamic analysis indicated an exothermic nature of adsorption and a spontaneous and favorable process. The m-Cell/Fe₃O₄/ACCs might be a promising candidate of high efficiency, low cost and convenient separation under magnetic field.
Background
Altered visceral sensation is common in irritable bowel syndrome (IBS) and nerve growth factor (NGF) participates in visceral pain development. Sodium butyrate (NaB) could induce colonic ...hypersensitivity via peripheral up‐regulation of NGF in animals. Enteric glial cells (EGCs) appear to be an important source of NGF. Whether butyrate could induce visceral hypersensitivity via increased EGC‐derived NGF is still unknown.
Methods
CRL‐2690 cells were used for transcriptome analyses after butyrate treatment. Rats received butyrate enemas to induce colonic hypersensitivity. Colorectal distention test was performed to assess visceral sensitivity. Immunofluorescence studies were used to evaluate the co‐expression of glial fibrillary acidic protein (GFAP) and NGF or growth associated protein 43 in animal model. NGF expression in rat colon was also investigated. In vitro, CRL‐2690 cells were stimulated with NaB or trichostatin A (TSA). NGF or GFAP expression was also examined.
Key Results
Transcriptome analyses showed that butyrate induced marked changes of genes expression related to neurotrophic signaling pathways. NaB‐treated rats showed increased visceral sensitivity. An improved NGF expression level was observed in NaB‐treated rats. Meanwhile, a 2.1‐fold increase in co‐expression of GFAP and NGF was also determined in rats received NaB enemas. In cultured cells, both NaB and TSA treatment could cause obvious NGF expression. Thus, butyrate might regulate EGC function via histone deacetylase inhibition.
Conclusions & Inferences
Butyrate‐EGC interplay may play a pivotal role in regulation of NGF expression and the development of colonic hypersensitivity in IBS‐like animal model.
Our study illustrated that butyrate promoted the secretion of NGF from enteric glial cells (EGCs) and contributed to visceral hypersensitivity in rats. The results clarified the potential unignorable source of NGF from EGC and highlighted the important role of EGC in pathogenesis of irritable bowel syndrome (IBS).
We present improved germanium-based constraints on sub-GeV dark matter via dark matter-electron (χ-e) scattering using the 205.4 kg·day dataset from the CDEX-10 experiment. Using a novel calculation ...technique, we attain predicted χ-e scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvement for m_{χ} larger than 80 MeV/c^{2} compared to previous germanium-based χ-e results. We also present the most stringent χ-e cross-section limit to date among experiments using solid-state detectors for m_{χ} larger than 90 MeV/c^{2} with heavy mediators and m_{χ} larger than 100 MeV/c^{2} with electric dipole coupling. The result proves the feasibility and demonstrates the vast potential of a new χ-e detection method with high-purity germanium detectors in ultralow radioactive background.
Aim The aim of the study was to evaluate the efficacy and safety of fast‐track rehabilitation in elderly patients over 65 years of age, following laparoscopic surgery to remove colorectal cancer.
...Method A total of 78 elderly patients with colorectal cancer who underwent laparoscopic colorectal resection were randomly assigned to receive either the fast‐track care programme (n = 40) or the conventional perioperative care protocol (control group, n = 38). Medical personnel conducting the study were blinded to patients’ clinical outcomes prior to statistical analysis. The fast‐track protocol included no preoperative mechanical bowel irrigation, immediate oral alimentation and earlier postoperative ambulation exercise. The length of postoperative hospital stay, the length of time to regain bowel function and the rate of postoperative complications were compared between the two groups.
Results The length of time to regain bowel function, including the passage of flatus31 (26–40) h vs 38 (32–51) h, P = 0.001, to the first bowel movement 55 (48–63) h vs 64 (48–71) h, P = 0.009 and to start a liquid diet (12 11–16 h vs 47 35–50 h, P = 0.000) were significantly shorter in patients receiving the fast‐track care protocol compared with those receiving the conventional care protocol. A shorter duration of postoperative hospital stay was recorded in patients receiving the fast‐track program than in those receiving conventional care (P = 0.0001). A reduced percentage of patients who developed general complications was also observed in the fast‐track group (5.0%vs 21.1%, P = 0.045).
Conclusion This randomized controlled trial has shown that in the elderly undergoing laparoscopic colorectal surgery, the fast‐track recovery programme resulted in a more rapid postoperative recovery, earlier discharge from hospital and fewer general complications compared with a conventional postoperative protocol.
PDF
