Topological Photonic Phase in Chiral Hyperbolic Metamaterials

Recently the possibility of achieving one-way backscatter immune transportation of light by mimicking the topological order present within certain solid state systems, such as topological insulators, has received much attention. Thus far however, demonstrations of non-trivial topology in photonics have relied on photonic crystals with precisely engineered lattice structures, periodic on the scale of the operational wavelength and composed of finely tuned, complex materials. Here we propose a novel effective medium approach towards achieving topologically protected photonic surface states robust against disorder on all length scales and for a wide range of material parameters. Remarkably, the non-trivial topology of our metamaterial design results from the Berry curvature arising from the transversality of electromagnetic waves in a homogeneous medium. Our investigation therefore acts to bridge the gap between the advancing field of topological band theory and classical optical phenomena such as the Spin Hall effect of light. The effective medium route to topological phases will pave the way for highly compact one-way transportation of electromagnetic waves in integrated photonic circuits.Comment: 11 pages, 3 figures. To appear in PR

Estradiol regulates miR-135b and mismatch repair gene expressions via estrogen receptor-β in colorectal cells.

Estrogen has anti-colorectal cancer effects which are thought to be mediated by mismatch repair gene (MMR) activity. Estrogen receptor (ER) expression is associated with microRNA (miRNA) expression in ER-positive tumors. However, studies of direct link between estrogen (especially estradiol E2), miRNA expression, and MMR in colorectal cancer (CRC) have not been done. In this study, we first evaluated the effects of estradiol (E2) and its antagonist ICI182,780 on the expression of miRNAs (miR-31, miR-155 and miR-135b) using COLO205, SW480 and MCF-7 cell lines, followed by examining the association of tissue miRNA expression and serum E2 levels using samples collected from 18 colorectal cancer patients. E2 inhibited the expressions of miRNAs in COLO205 cells, which could be reversed by E2 antagonist ICI 182.780. The expression of miR-135b was inversely correlated with serum E2 level and ER-β mRNA expression in CRC patients' cancer tissues. There were significant correlations between serum E2 level and expression of ER-β, miR-135b, and MMR in colon cancer tissue. This study suggests that the effects of estrogen on MMR function may be related to regulating miRNA expression via ER-β, which may be the basis for the anti-cancer effect in colorectal cells

A Systematic Review on Human Capital: A View From Human Resource Development

With rising globalisation and the overcrowding of the employment market because of recent crises in numerous economies throughout the world, human capital is receiving more attention. Both developed and developing countries place a greater emphasis on human capital development to accelerate economic growth by dedicating the required time and effort. As a result, one of the most important means of accessing the global stage is to build human capital. Firms must devote the required resources to building human capital, which has a significant influence on performance. From several critical viewpoints, this research investigates the extent to which human capital has direct implications on corporate performance. This survey also intends to review 42 human capital related papers. Additionally, this paper provides a comprehensive study concerning the chronological review based on each publication, while also focusing on and reviewing the topic knowledge utilizing a systematic literature review. Finally, this paper develops a model that explains the relationship between human capital and firm performance. Keywords: HRM practices, organization performance, human resource capital, human capital investment, employee engagemen

Suppression of Exosomal PD-L1 Induces Systemic Anti-tumor Immunity and Memory.

PD-L1 on the surface of tumor cells binds its receptor PD-1 on effector T cells, thereby suppressing their activity. Antibody blockade of PD-L1 can activate an anti-tumor immune response leading to durable remissions in a subset of cancer patients. Here, we describe an alternative mechanism of PD-L1 activity involving its secretion in tumor-derived exosomes. Removal of exosomal PD-L1 inhibits tumor growth, even in models resistant to anti-PD-L1 antibodies. Exosomal PD-L1 from the tumor suppresses T cell activation in the draining lymph node. Systemically introduced exosomal PD-L1 rescues growth of tumors unable to secrete their own. Exposure to exosomal PD-L1-deficient tumor cells suppresses growth of wild-type tumor cells injected at a distant site, simultaneously or months later. Anti-PD-L1 antibodies work additively, not redundantly, with exosomal PD-L1 blockade to suppress tumor growth. Together, these findings show that exosomal PD-L1 represents an unexplored therapeutic target, which could overcome resistance to current antibody approaches

Political connections and minority-shareholder protection: Evidence from securities-market regulation in China

We examine the wealth effects of three regulatory changes designed to improve minorityshareholder protection in the Chinese stock markets. Using the value of a firm’s related-party transactions as an inverse proxy for the quality of corporate governance, we find that firms with weaker governance experienced significantly larger abnormal returns around announcements of the new regulations than did firms with stronger governance. This evidence indicates that securities-market regulation can be effective in protecting minority shareholders from expropriation in a country with weak judicial enforcement. We also find that firms with strong ties to the government did not benefit from the new regulations, suggesting that minority shareholders did not expect regulators to enforce the new rules on firms where block holders have strong political connections

Improving corporate governance where the State is the controlling block holder: Evidence from China

We examine changes in market values and accounting returns for a sample of publicly traded Chinese firms around announcements of block-share transfers among government agencies (“State Bureaucrats”), market-oriented State-owned enterprises (“MOSOEs”) and private investors (“Private Entities”). We provide evidence that transfers from State Bureaucrats to Private Entities result in larger increases in market value and accounting returns than transfers to MOSOEs. We also find that CEO turnover occurs more quickly when shares are transferred to Private Entities. Moreover, we find that the changes in firm value and accounting returns, as well as the likelihood of CEO turnover, are all functions of the incentives and managerial expertise of the new block holder. We conclude that corporate governance can be improved at State-controlled firms by improving the incentives and managerial expertise of controlling block holders, and that this is better accomplished by transferring ownership to private investors rather than by shuffling ownership among Statecontrolled entities

Agency Conflicts, Expropriation and Firm Value: Evidence from Securities-Market Regulation in China

In this study, we examine the wealth effects of regulatory changes intended to improve corporate governance by protecting minority shareholders from expropriation by controlling shareholders. Using data from publicly traded Chinese firms, we find that these new regulations significantly increased firm value, and that firms with weak governance disproportionately benefited relative to firms with strong governance. Our evidence provides new support for the theory of La Porta et al. (2002) that better investor protection results in higher firm valuations. It also is supportive of the theory of Glaeser, Johnson and Shleifer (2001) that securities-market regulation can create substantial value for minority shareholders in a country with weak judicial enforcement. Finally, it is consistent with Black and Kraakman (1996), who argue that, in rule-based civil-law countries, regulation in the form of simple “bright-line rules” is more effective than in the form of “broad standards.