General properties of fidelity in non-Hermitian quantum systems with PT symmetry

The fidelity susceptibility is a tool for studying quantum phase transitions in the Hermitian condensed matter systems. Recently, it has been generalized with the biorthogonal basis for the non-Hermitian quantum systems. From the general perturbation description with the constrain of parity-time (PT) symmetry, we show that the fidelity $\mathcal{F}$ is always real for the PT-symmetric states. For the PT-broken states, the real part of the fidelity susceptibility equals to one half of the sum of the fidelity susceptibility of the PT-broken and the PT-partner states, $\mathrm{Re}[\mathcal{X}_F] = \frac{1}{2}(\mathcal{X}_F +\bar{\mathcal{X}}_F)$. The negative infinity of the fidelity susceptibility is explored by the perturbation theory when the parameter approaches the exceptional point (EP). Moreover, at the second-order EP where two eigenstates and eigenenergies coalesce, we prove that the real part of the fidelity between PT-symmetric and PT-broken states is $\mathrm{Re}\mathcal{F}=\frac{1}{2}$. We demonstrate these general properties for non-interacting and interacting systems by two examples: the two-legged non-Hermitian Su-Schrieffer-Heeger (SSH) model and the non-Hermitian XXZ spin chain.Comment: 14 pages, 8 figure

Effects of Quality of Financial Statements and CEO Turnover

The purpose of this study is to explore the effect of CEO turnover and CFO turnover on earnings management. In addition, Taiwan’s authorities will require listed companies to complete the establishment of audit committee replacing supervisors in 2022. Corporate governance is not an overnight phenomenon. It has been existing from a long time. It is only that the beginning of 21st century when colossal enterprises started to fall, government across globe started giving it due credit. The present paper is an attempt to trace the history of corporate governance. It starts with discussing various theories which led to the development of such an important concept and then dwells on various models in which economies employ corporate governance in their structure and finally the evolution of corporate governance across globe. The paper sheds light on important committees and reforms which have been the genesis of corporate governance across globe. It undertakes an extensive literature review on different aspects of corporate governance. Corporate governance is a concept which still debatable among experts in describing it. The purpose of this study is to explore how the implementation and principal problems of good corporate governance in the management of current limited liability company

The impact of social comparison on the neural substrates of reward processing: An event-related potential study

Event-related potentials (ERPs) were recorded to explore the electrophysiological correlates of reward processing in the social comparison context when subjects performed a simple number estimation task that entailed monetary rewards for correct answers. Three social comparison stimulus categories (three relative reward levels/self reward related to the other subject\u27s) were mainly prepared: Self:Other=1:2 (Disadvantageous inequity condition); Self:Other=1:1 (Equity condition); and Self:Other=2:1 (Advantageous inequity condition). Results showed that: both Disadvantageous and Advantageous inequity elicited a more negative ERP deflection (N350–550) than did Equity between 350 and 550 ms, and the generators of N350–550 were localized near the parahippocampal gyrus and the medial frontal/anterior cingulate cortex, which might be related to monitor and control reward prediction error during reward processing. Then, Disadvantageous and Advantageous inequity both elicited a more late negative complex (LNC1 and LNC2) than did Equity between 550 and 750 ms. The generators of LNC1 and LNC2 were both localized near the caudate nucleus, which might be related to reward processing under social comparison

Systematic Analysis of Head-to-Head Gene Organization: Evolutionary Conservation and Potential Biological Relevance

Several “head-to-head” (or “bidirectional”) gene pairs have been studied in individual experiments, but genome-wide analysis of this gene organization, especially in terms of transcriptional correlation and functional association, is still insufficient. We conducted a systematic investigation of head-to-head gene organization focusing on structural features, evolutionary conservation, expression correlation and functional association. Of the present 1,262, 1,071, and 491 head-to-head pairs identified in human, mouse, and rat genomes, respectively, pairs with 1– to 400–base pair distance between transcription start sites form the majority (62.36%, 64.15%, and 55.19% for human, mouse, and rat, respectively) of each dataset, and the largest group is always the one with a transcription start site distance of 101 to 200 base pairs. The phylogenetic analysis among Fugu, chicken, and human indicates a negative selection on the separation of head-to-head genes across vertebrate evolution, and thus the ancestral existence of this gene organization. The expression analysis shows that most of the human head-to-head genes are significantly correlated, and the correlation could be positive, negative, or alternative depending on the experimental conditions. Finally, head-to-head genes statistically tend to perform similar functions, and gene pairs associated with the significant cofunctions seem to have stronger expression correlations. The findings indicate that the head-to-head gene organization is ancient and conserved, which subjects functionally related genes to correlated transcriptional regulation and thus provides an exquisite mechanism of transcriptional regulation based on gene organization. These results have significantly expanded the knowledge about head-to-head gene organization. Supplementary materials for this study are available at http://www.scbit.org/h2h

Dissection of the mechanism of traditional Chinese medical prescription-Yiqihuoxue formula as an effective anti-fibrotic treatment for systemic sclerosis

BACKGROUND: Systemic sclerosis (SSc) is a connective tissue fibrotic disease for which there is no effective treatment. Traditional Chinese Medicine (TCM), such as the Yiqihuoxue formula used in Shanghai TCM-integrated Hospital, has shown the efficacy of anti-fibrosis in clinical applications. This study was aiming to dissect the anti-fibrotic mechanism of Yiqihuoxue treatment for SSc. METHODS: Bleomycin-induced mice and SSc dermal fibroblasts were treated with Yiqihuoxue decoction; NIH-3T3 fibroblasts were exposed to exogenous TGF-β1, and then cultured with or without Yiqihuoxue decoction. Luciferase reporter gene assay was used to determine the activity of Smad binding element (SBE). Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to examine the mRNA levels of extracellular matrix (ECM) genes. The protein levels of type I collagen, Smad3 and phosphorylated-Smad3 (p-Smad3) were detected by western blotting. Student’s t-tests were used to determine the significance of the results. RESULTS: Bleomycin-induced mice, SSc dermal fibroblasts and TGF-β1-induced NIH/3T3 fibroblasts showed higher levels of ECM gene transcriptions and collagen production. In addition, the phosphorylation level of Smad3 and activity of SBE were significantly increased after exogenous TGF-β1 induction. Whereas, Yiqihuoxue treatment could obviously attenuate fibrosis in bleomycin-induced mice, down regulate ECM gene expressions and collagen production in SSc dermal fibroblasts and TGF-β1-induced NIH/3T3 fibroblasts. Furthermore, the aberrantly high phosphorylation level of Smad3 and activity of SBE in the TGF-β1-induced NIH/3T3 fibroblasts were also dramatically decreased by Yiqihuoxue treatment. CONCLUSIONS: Yiqihuoxue treatment could effectively reduce collagen production via down-regulating the phosphorylation of Smad3 and then the activity of SBE, which are involved in the TGF-β pathway and constitutively activated in the progression of SSc

Screening therapeutic EMT blocking agents in a three-dimensional microenvironment

Epithelial–mesenchymal transition (EMT) plays a critical role in the early stages of dissemination of carcinoma leading to metastatic tumors, which are responsible for over 90% of all cancer-related deaths. Current therapeutic regimens, however, have been ineffective in the cure of metastatic cancer, thus an urgent need exists to revisit existing protocols and to improve the efficacy of newly developed therapeutics. Strategies based on preventing EMT could potentially contribute to improving the outcome of advanced stage cancers. To achieve this goal new assays are needed to identify targeted drugs capable of interfering with EMT or to revert the mesenchymal-like phenotype of carcinoma to an epithelial-like state. Current assays are limited to examining the dispersion of carcinoma cells in isolation in conventional 2-dimensional (2D) microwell systems, an approach that fails to account for the 3-dimensional (3D) environment of the tumor or the essential interactions that occur with other nearby cell types in the tumor microenvironment. Here we present a microfluidic system that integrates tumor cell spheroids in a 3D hydrogel scaffold, in close co-culture with an endothelial monolayer. Drug candidates inhibiting receptor activation or signal transduction pathways implicated in EMT have been tested using dispersion of A549 lung adenocarcinoma cell spheroids as a metric of effectiveness. We demonstrate significant differences in response to drugs between 2D and 3D, and between monoculture and co-culture.Singapore. National Research Foundation (Singapore MIT Alliance for Research and Technology's BioSystems and Micromechanics Inter-Disciplinary Research programme)National University of Singapore (Cancer Science Institute)Singapore. Agency for Science, Technology and ResearchSingapore. Institute of Molecular and Cell Biology (IMCB core funding A*STAR

Screening therapeutic EMT blocking agents in a three-dimensional microenvironment

Epithelial–mesenchymal transition (EMT) plays a critical role in the early stages of dissemination of carcinoma leading to metastatic tumors, which are responsible for over 90% of all cancer-related deaths. Current therapeutic regimens, however, have been ineffective in the cure of metastatic cancer, thus an urgent need exists to revisit existing protocols and to improve the efficacy of newly developed therapeutics. Strategies based on preventing EMT could potentially contribute to improving the outcome of advanced stage cancers. To achieve this goal new assays are needed to identify targeted drugs capable of interfering with EMT or to revert the mesenchymal-like phenotype of carcinoma to an epithelial-like state. Current assays are limited to examining the dispersion of carcinoma cells in isolation in conventional 2-dimensional (2D) microwell systems, an approach that fails to account for the 3-dimensional (3D) environment of the tumor or the essential interactions that occur with other nearby cell types in the tumor microenvironment. Here we present a microfluidic system that integrates tumor cell spheroids in a 3D hydrogel scaffold, in close co-culture with an endothelial monolayer. Drug candidates inhibiting receptor activation or signal transduction pathways implicated in EMT have been tested using dispersion of A549 lung adenocarcinoma cell spheroids as a metric of effectiveness. We demonstrate significant differences in response to drugs between 2D and 3D, and between monoculture and co-culture.Singapore. National Research Foundation (Singapore MIT Alliance for Research and Technology's BioSystems and Micromechanics Inter-Disciplinary Research programme)National University of Singapore (Cancer Science Institute)Singapore. Agency for Science, Technology and ResearchSingapore. Institute of Molecular and Cell Biology (IMCB core funding A*STAR