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.
Aims
A thermostable endo‐mannanase from the fungus Talaromyces cellulolyticus was identified to facilitate manno‐oligosaccharide preparation from Konjac (Amorphophallus konjac) flour.
Methods and ...Results
A putative endo‐1,4‐β‐mannanase from the T. cellulolyticus was obtained and efficiently expressed by improving its gene dosage in the genome of the host. After cultivation in a bench‐top bioreactor for about 120 h, the protein content and enzyme activity of mannanase increased to 3·4 g l−1 and 17 500 U ml−1 respectively. Enzymatic characterization showed that this enzyme has an optimal temperature of 80°C, optimal pH of 5·0. Under the optimized hydrolysis conditions of pH 5·0, 70°C, and an enzyme concentration of 200 U l−1 solution, this enzyme could efficiently hydrolyse 0·5% konjac flour into manno‐oligosaccharides (MOSs) with the degree of polymerization range from 3 to 7. The possible mechanism by which the enzyme produced MOSs was also discussed.
Conclusion
Talaromyces cellulolyticus endo‐mannanase is thermostable and has a broad pH range adaptability. Method of improving the dosage of mannanase gene in the genome could realized its high‐level impression. This enzyme could efficiently hydrolyse konjac flour into manno‐oligosaccharide products.
Significance and Impact of the Study
This study has enriched endo‐mannanase resources, facilitated its bulk production and provided a strong reference for its application in manno‐oligosaccharide preparation from the natural glucomannan of konjac flour.
Transition metal-catalyzed arene functionalization has been widely used for molecular synthesis over the past century. In this arena, copper catalysis has long been considered a privileged platform ...due to the propensity of high-valent copper to undergo reductive elimination with a wide variety of coupling fragments. However, the sluggish nature of oxidative addition has limited copper's capacity to broadly facilitate haloarene coupling protocols. Here, we demonstrate that this copper oxidative addition problem can be overcome with an aryl radical-capture mechanism, wherein the aryl radical is generated through a silyl radical halogen abstraction. This strategy was applied to a general trifluoromethylation of aryl bromides through dual copper-photoredox catalysis. Mechanistic studies support the formation of an open-shell aryl species.
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.
Summary
Background
TCS (topical corticosteroids) are the first‐line drug in the treatment of oral lichen planus (OLP). However, the value of topical calcineurin inhibitors (TCI) including tacrolimus, ...pimecrolimus and ciclosporin for OLP is still controversial.
Objectives
To compare the efficacy and safety of TCI vs. TCS for OLP.
Methods
The authors searched PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science and four Chinese databases from 1950 to May 2018. The randomized controlled trials comparing TCI and TCS for OLP reported at least one of the following outcomes: improvement of clinical signs and/or symptoms, relapse, blood levels of TCI and adverse events.
Results
Twenty‐one trials involving 965 patients were included in the analysis. For the treatment of OLP (3–8 weeks), TCI including tacrolimus, pimecrolimus and ciclosporin were similar to TCS in efficacy. Tacrolimus–TCS resulted in similar outcomes, with relapse at 3 weeks to 6 months. Blood levels of TCI were usually undetectable. In addition, tacrolimus showed a statistically higher incidence of local adverse events than TCS for short‐term treatment. A few systemic adverse events occurred in the tacrolimus and ciclosporin groups, but they were not serious.
Conclusions
The evidence for tacrolimus (n = 12), pimecrolimus (n = 3) and ciclosporin (n = 6) demonstrated that treatment with TCI may be an alternative approach when OLP does not respond to the standard protocols. Tacrolimus 0·1% should be the first drug of choice when selecting TCI for short‐term treatment in recalcitrant OLP. Further well‐designed trials are warranted to evaluate the long‐term efficacy and safety of TCI.
What's already known about this topic?
The main topical drug for oral lichen planus (OLP) is topical corticosteroids (TCS).
Patients with OLP who are not responsive to TCS or are at risk of adverse events from TCS need other alternative drugs.
Topical calcineurin inhibitors (TCI), including tacrolimus, pimecrolimus and ciclosporin, have become a hot topic in a variety of mucocutaneous immune‐mediated diseases.
What does this study add?
TCI including tacrolimus, pimecrolimus and ciclosporin were similar to TCS in efficacy for the short‐term treatment of OLP.
The local adverse events of tacrolimus were higher than with TCS. A few systemic adverse events were reported with TCI, but they were all tolerable and not serious.
The limited evidence for pimecrolimus (three trials) and ciclosporin (six trials) requires further studies to evaluate the short‐term and long‐term efficacy and safety of TCI compared with TCS.
Linked Comment: Thongprasom. Br J Dermatol 2019; 181:1120.
Plain language summary available online
Multiferroics, where (anti-) ferromagnetic, ferroelectric and ferroelastic order parameters coexist, enable manipulation of magnetic ordering by an electric field through switching of the electric ...polarization. It has been shown that realization of magnetoelectric coupling in a single-phase multiferroic such as BiFeO3 requires ferroelastic (71 , 109 ) rather than ferroelectric (180 ) domain switching. However, the control of such ferroelastic switching in a single-phase system has been a significant challenge as elastic interactions tend to destabilize small switched volumes, resulting in subsequent ferroelastic back-switching at zero electric field, and thus the disappearance of non-volatile information storage. Guided by our phase-field simulations, here we report an approach to stabilize ferroelastic switching by eliminating the stress-induced instability responsible for back-switching using isolated monodomain BiFeO3 islands. This work demonstrates a critical step to control and use non-volatile magnetoelectric coupling at the nanoscale. Beyond magnetoelectric coupling, it provides a framework for exploring a route to control multiple order parameters coupled to ferroelastic order in other low-symmetry materials.
Abstract
The most fascinating feature of certain two-dimensional (2D) gapless quantum spin liquid (QSL) is that their spinon excitations behave like the fermionic carriers of a paramagnetic metal. ...The spinon Fermi surface is then expected to produce a linear increase of the thermal conductivity with temperature that should manifest via a residual value (
κ
0
/
T
) in the zero-temperature limit. However, this linear in
T
behavior has been reported for very few QSL candidates. Here, we studied the ultralow-temperature thermal conductivity of an effective spin-1/2 triangular QSL candidate Na
2
BaCo(PO
4
)
2
, which has an antiferromagnetic order at very low temperature (
T
N
~ 148 mK), and observed a finite
κ
0
/
T
extrapolated from the data above
T
N
. Moreover, while approaching zero temperature, it exhibits series of quantum spin state transitions with applied field along the
c
axis. These observations indicate that Na
2
BaCo(PO
4
)
2
possibly behaves as a gapless QSL with itinerant spin excitations above
T
N
and its strong quantum spin fluctuations persist below
T
N
.
We re-estimate the peculiar velocity of the Sun with respect to the local standard of rest (LSR) using a sample of local stars within 600 pc of the Sun, selected from the Large Sky Area Multi-Object ...Fiber Spectroscopic Telescope (LAMOST, also named the Guoshoujing Telescope) Spectroscopic Survey of the Galactic Anti-centre (LSS-GAC). The sample consists of 94 332 FGK main-sequence stars with well-determined radial velocities and atmospheric parameters. To derive the LSR, two independent analyses are applied to the data. First, we determine the solar motion by comparing the observed velocity distribution to that generated with the analytic formulism of Schönrich & Binney that has been demonstrated to show excellent agreement with rigorous torus-based dynamics modelling by Binney & McMillan. Secondly, we propose that cold populations of thin disc stars, selected by applying an orbital eccentricity cut, can be directly used to determine the LSR without the need of asymmetric drift corrections. Both approaches yield consistent results of solar motion in the direction of Galactic rotation, V
⊙, that are much higher than the standard value adopted hitherto, derived from Strömgren's equation. The newly deduced values of V
⊙ are 1–2 km s−1 smaller than the more recent estimates derived from the Geneva–Copenhagen Survey (GCS) sample of stars in the solar neighbourhood (within 100 pc). We attribute the small difference to the presence of several well-known moving groups in the GCS sample that, fortunately, hardly affect the LSS-GAC sample. The newly derived radial (U
⊙) and vertical (W
⊙) components of the solar motion agree well with the previous studies. In addition, for all components of the solar motion, the values yielded by stars of different spectral types in the LSS-GAC sample are consistent with each other, suggesting that the local disc is well relaxed and that the LSR reported in the current work is robust. Our final recommended LSR is, (U⊙, V⊙, W⊙) = (7.01 ± 0.20, 10.13 ± 0.12, 4.95 ± 0.09) km s−1.
Weak bi-Frobenius algebras Chen, Q. G.
Communications in algebra,
01/2024, Letnik:
52, Številka:
4
Journal Article
Recenzirano
As a double generalization of biFrobenius algebras and weak Hopf algebra, we introduce and study weak biFrobenius algebras (or briefly wbF algebras). A wbF algebra is a Frobenius algebra and a ...Frobenius coalgebra and satisfies some compatibility conditions. We discuss more properties of wbF algebras keeping as close as possible to the classical theory of weak Hopf algebras, and give conditions for finite dimensional algebras and coalgebras to be wbF algebras. Then we studies substructures in wbF algebras. Finally, we prove that our wbF algebras can give rise to Frobenius double algebras in sense of Szlachányi.
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