338 research outputs found
Prediction of interesting ferromagnetism in Janus semiconducting CrAsP monolayer
Two-dimensional (2D) half-metallic materials that have sparked intense
interest in advanced spintronic applications are essential to the developing
next-generation nanospintronic devices. Here we have adopted a first-principles
calculation method to predict the magnetic properties of intrinsic, Se-doped,
and biaxial strain tuning CrAsP monolayer. The Janus CrAsP monolayer is
proved to be an intrinsic ferromagnetic (FM) semiconductor with a exchange
splitting bandgap of 0.15 eV at the PBE+U level. Concentration-dependent Se
doping such as CrAsSeP (x = 0.25, 0.50, 0.75) can regulate
CrAsP from FM semiconductor to FM half-metallicity. Specifically, the
spin-up channel crosses the Fermi level, while the spin-down channel has a
bandgap. More interestingly, the wide half-metallic bandgaps and spin bandgaps
make them have important implications for the preparation of spintronic
devices. At last, we also explore the effect of biaxial strain from -14% to 10%
on the magnetism of the CrAsP monolayer. There appears a transition from FM
to antiferromagnetic (AFM) at a compressive strain of -10.7%, originating from
the competition between the indirect FM superexchange interaction and the
direct AFM interaction between the nearest-neighbor Cr atoms. Additionally,
when the compressive strain to -2% or the tensile strain to 6%, the
semiconducting CrAsP becomes a half-metallic material. These charming
properties render the Janus CrAsP monolayer with great potential for
applications in spintronic devices.Comment: 14 pages, 4 figure
Earnings Management for Second-time IPOs: Evidence from China
In China’s IPO market, firms that fail in their first IPO application make considerable adjustments before making their second IPO application. Examining firms that applied for IPOs during 2004-2018, we find that failed IPO applicant firms “package” themselves to obtain approval of the China Securities Regulatory Commission (CSRC) by reducing accrual earnings management and increasing real earnings management. In addition, after a successful second IPO application, these firms relax their vigilance vis-à-vis the CSRC and increase both accrual and real earnings management. This pre-IPO “packaging” behavior deceives investors, leading to higher IPO prices and higher post-IPO returns
Structural nonlinear vibration reliability analysis based on improved ant colony algorithm
To improve the efficiency of the structural nonlinear vibration reliability optimization, the solution of the structural reliability index is converted into the corresponding unconstrained optimization problem by combining with the penalty function method through the analysis of the geometric meaning. And a novel ant colony algorithm is employed to solve the optimization problem. The introduction of ants transfer strategy makes the algorithm expand the search range in the early phase, and improve the convergence rate in the late which can overcome the defects of precocity and stagnation. Finally, the improved ant colony algorithm was used to find the shortest failure paths of the structure. Engineering practice and comparison with other algorithms demonstrate the strong applicability and validity of the method
First-principles calculations on the mechanical, electronic, magnetic and optical properties of two-dimensional Janus CrTeX (X= P, As, Sb) monolayers
Janus materials possess extraordinary physical, chemical, and mechanical
properties caused by symmetry breaking. Here, the mechanic properties,
electronic structure, magnetic properties, and optical properties of Janus
CrTeX (X= P, As, Sb) monolayers are systematically investigated by the
density functional theory. Janus CrTeP, CrTeAs, and CrTeSb are
intrinsic ferromagnetic (FM) half-metals with wide spin gaps and half-metallic
gaps. Monte Carlo simulations based on the Heisenberg model estimate the Curie
temperature (\emph{T}) of these monolayers are about 583, 608, and 597 K,
respectively. Additionally, it is found that CrTeX (X= P, As, Sb)
monolayers still exhibit FM half-metallic properties under biaxial strain from
-6% to 6%. At last, the CrTeP monolayer has a higher absorption coefficient
than the CrTeAs and CrTeSb monolayers in the visible region. The
results predict that Janus CrTeX (X= P, As, Sb) monolayers with novel
properties have good potential for applications in future nanodevices.Comment: 14 pages, 5 figure
HSP27 Alleviates Cardiac Aging in Mice via a Mechanism Involving Antioxidation and Mitophagy Activation
Aging-induced cardiac dysfunction is a prominent feature of cardiac aging. Heat shock protein 27 (HSP27) protects cardiac function against ischemia or chemical challenge. We hypothesized that HSP27 attenuates cardiac aging. Transgenic (Tg) mice with cardiac-specific expression of the HSP27 gene and wild-type (WT) littermates were employed in the experiments. Echocardiography revealed a significant decline in the cardiac function of old WT mice compared with young WT mice. In striking contrast, the aging-induced impairment of cardiac function was attenuated in old Tg mice compared with old WT mice. Levels of cardiac aging markers were lower in old Tg mouse hearts than in old WT mouse hearts. Less interstitial fibrosis and lower contents of reactive oxygen species and ubiquitin-conjugated proteins were detected in old Tg hearts than in old WT hearts. Furthermore, old Tg hearts demonstrated lower accumulation of LC3-II and p62 than old WT hearts. Levels of Atg13, Vps34, and Rab7 were also higher in old Tg hearts than in old WT hearts. Additionally, old Tg hearts had higher levels of PINK1 and Parkin than old WT hearts, suggesting that mitophagy was activated in old Tg hearts. Taken together, HSP27 alleviated cardiac aging and this action involved antioxidation and mitophagy activation
A Noise-Tolerant Zeroing Neural Network for Time-Dependent Complex Matrix Inversion Under Various Kinds of Noises
Complex-valued time-dependent matrix inversion (TDMI) is extensively exploited in practical industrial and engineering fields. Many current neural models are presented to find the inverse of a matrix in an ideal noise-free environment. However, the outer interferences are normally believed to be ubiquitous and avoidable in practice. If these neural models are applied to complex-valued TDMI in a noise environment, they need to take a lot of precious time to deal with outer noise disturbances in advance. Thus, a noise-suppression model is urgent to be proposed to address this problem. In this article, a complex-valued noise-tolerant zeroing neural network (CVNTZNN) on the basis of an integral-type design formula is established and investigated for finding complex-valued TDMI under a wide variety of noises. Furthermore, both convergence and robustness of the CVNTZNN model are carefully analyzed and rigorously proved. For comparison and verification purposes, the existing zeroing neural network (ZNN) and gradient neural network (GNN) have been presented to address the same problem under the same conditions. Numerical simulation consequences demonstrate the effectiveness and excellence of the proposed CVNTZNN model for complex-valued TDMI under various kinds of noises, by comparing the existing ZNN and GNN models
HSPA12B Attenuated Acute Myocardial Ischemia/reperfusion Injury via Maintaining Endothelial Integrity in a PI3K/Akt/mTOR-dependent Mechanism
Endothelial damage is a critical mediator of myocardial ischemia/reperfusion (I/R) injury. HSPA12B is an endothelial-cell-specifically expressed heat shock protein. However, the roles of HSPA12B in acute myocardial I/R injury is unknown. Here we reported that myocardial I/R upregulated HSPA12B expression in ventricular tissues, and endothelial overexpression of HSPA12B in transgenic mice (Tg) limited infarct size, attenuated cardiac dysfunction and improved cardiomyocyte survival compared with their wild type littermates. These improvements were accompanied with the diminished myocardial no-reflow phenomenon, decreased microvascular leakage, and better maintained endothelial tight junctions. The I/R-evoked neutrophil infiltration was also suppressed in Tg hearts compared with its wild type (WT) littermates. Moreover, Tg hearts exhibited the enhanced activation of PI3K/Akt//mTOR signaling following I/R challenge. However, pharmacological inhibition of PI3K abolished the HSPA12B-induced cardioprotection against myocardial I/R injury. The data demonstrate for the first time that the endothelial HSPA12B protected hearts against myocardial I/R injury. This cardioprotective action of HSPA12B was mediated, at least in part, by improving endothelial integrity in a PI3K/Akt/mTOR-dependent mechanism. Our study suggests that targeting endothelial HSPA12B could be an alternative approach for the management of patients with myocardial I/R injury
1, 25-Dihydroxyvitamin D3 suppresses cell cycle progression and thus growth of prostate cancer cells by inducing expression of limb bud and heart development (LBH)
Purpose: To investigate the function of limb bud and heart development (LBH) in 1α, 25-dihydroxyvitamin D3 (1,25D)-mediated inhibitory effect on proliferation of prostate cancer cells.Methods: The inhibitory effect of 1,25D on growth and cell cycle progression of lymph node carcinoma of the prostate (LNCaP) cells was determined using cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay and flow cytometry, while the expression levels of LBH in response to treatment with 1,25D were determined by quantitative reverse-transcription PCR (qRT-PCR) and western blottingting. The expression levels of LBH in cells were down/up regulated by transfection with siRNA or overexpression plasmids, and then cell growth and cell cycles were measured using the CCK-8 assay, EdU assay, and flow cytometry. Finally, the growth inhibitory effect of 1,25D on LBH knockdown cells were determined using CCK-8 and EdU assays.Results: Treatment with 1,25D arrested LNCaP cells in G0/G1 phase of cell cycle, suppressed the growth of the cells and induced the expression of LBH. Overexpression/knockdown of LBH in LNCaP cells suppressed/promoted cell growth and accumulated/decreased cells in the G0/G1 phase. Moreover, knockdown of LBH reversed the inhibitory effect of 1,25D on cell proliferation of LNCaP cells.Conclusion: Inhibitory effect of 1,25D on cell cycle progression and cell proliferation might be via LBH.Keywords: Cell proliferation, Limb bud and heart development, Prostate cancer, 1α, 25-Dihydroxyvitamin D
VLM-Eval: A General Evaluation on Video Large Language Models
Despite the rapid development of video Large Language Models (LLMs), a
comprehensive evaluation is still absent. In this paper, we introduce a unified
evaluation that encompasses multiple video tasks, including captioning,
question and answering, retrieval, and action recognition. In addition to
conventional metrics, we showcase how GPT-based evaluation can match human-like
performance in assessing response quality across multiple aspects. We propose a
simple baseline: Video-LLaVA, which uses a single linear projection and
outperforms existing video LLMs. Finally, we evaluate video LLMs beyond
academic datasets, which show encouraging recognition and reasoning
capabilities in driving scenarios with only hundreds of video-instruction pairs
for fine-tuning. We hope our work can serve as a unified evaluation for video
LLMs, and help expand more practical scenarios. The evaluation code will be
available soon
Impacts of Future Climate Change on Net Primary Productivity of Grassland in Inner Mongolia, China
Net Primary Productivity (NPP) of grassland is a key variable of terrestrial ecosystems and is an important parameter for characterizing carbon cycles in grassland ecosystems. In this research, the Inner Mongolia grassland NPP was calculated using the Miami Model and the impact of climate change on grassland NPP was subsequently analyzed under the Special Report on Emissions Scenarios (SRES) A2, B2, and A1B scenarios, which are inferred from Providing Regional Climates for Impacts Studies (PRECIS) climate model system. The results showed that: (1) the NPP associated with these three scenarios had a similar distribution in Inner Mongolia: the grassland NPP increased gradually from the western region, with less than 200 g/m2/yr, to the southeast region, with more than 800 g/m2/yr. Precipitation was the main factor determining the grassland NPP; (2) compared with the baseline (1961-1990), there would be an overall increase in grassland NPP during three time periods (2020s: 2011-2040, 2050s: 2041-2070, and 2080s: 2071-2100) under the A2 and B2 scenarios; (3) under the A1B scenario, there will be a decreasing trend at middle-west region during the 2020s and 2050s; while there will be a very significant decrease from the 2050s to 2080s for middle Inner Mongolia; and (4) grassland NPP under the A1B scenario would present the most significant increase among the three scenarios, and would have the least significant increase under the B2 scenario
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