The Chinese University of Hong Kong

About: The Chinese University of Hong Kong is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Population & Computer science. The organization has 43411 authors who have published 93672 publications receiving 3066651 citations.

VAPB interacts with the mitochondrial protein PTPIP51 to regulate calcium homeostasis

Abstract: A proline to serine substitution at position 56 in the gene encoding vesicle-associated membrane protein-associated protein B (VAPB) causes some dominantly inherited familial forms of motor neuron disease including amyotrophic lateral sclerosis (ALS) type-8 VAPB is an integral endoplasmic reticulum (ER) protein whose amino-terminus projects into the cytosol Overexpression of ALS mutant VAPBP56S disrupts ER structure but the mechanisms by which it induces disease are not properly understood Here we show that VAPB interacts with the outer mitochondrial membrane protein, protein tyrosine phosphatase-interacting protein 51 (PTPIP51) ER and mitochondria are both stores for intracellular calcium (Ca2+) and Ca2+ exchange between these organelles occurs at regions of ER that are closely apposed to mitochondria These are termed mitochondria-associated membranes (MAM) We demonstrate that VAPB is a MAM protein and that loss of either VAPB or PTPIP51 perturbs uptake of Ca2+ by mitochondria following release from ER stores Finally, we demonstrate that VAPBP56S has altered binding to PTPIP51 and increases Ca2+ uptake by mitochondria following release from ER stores Damage to ER, mitochondria and Ca2+ homeostasis are all seen in ALS and we discuss the implications of our findings in this context

Shareholding structure and corporate performance of partially privatized firms: Evidence from listed Chinese companies

Abstract: Equity ownership in a listed Chinese firm can have as many as five different classes: state-owned shares, legal-person (LP) shares, tradable A-shares, employee shares, and shares only available to foreign investors, a phenomenon that is unique to the Chinese equity market. In this paper, we investigate whether and how the corporate performance of listed Chinese firms is affected by their shareholding structure. The sample consists of all firms listed in the Shanghai Stock Exchange (SHSE) from 1991 to 1996. It is found that firm performance is positively related to the proportion of LP shares but negatively related to the proportion of shares owned by the state. Additional analyses indicate that firm performance increases with the degree of relative dominance of LP shares over state shares. Moreover, for the subsample of firms that do not have both state and LP shares, the return on equity (ROE) of firms with LP shares but no state shares is higher than that of firms with state shares but no LP shares by 3.84%, and this difference is statistically significant. On the other hand, there is little evidence in support of a positive correlation between corporate performance and the proportion of tradable shares owned by either domestic or foreign investors. These findings suggest that the ownership structure composition and relative dominance by various classes of shareholders can affect the performance of state-owned enterprise (SOE)-transformed and listed firms.

A Hybrid Cloud Approach for Secure Authorized Deduplication

Abstract: Data deduplication is one of important data compression techniques for eliminating duplicate copies of repeating data, and has been widely used in cloud storage to reduce the amount of storage space and save bandwidth. To protect the confidentiality of sensitive data while supporting deduplication, the convergent encryption technique has been proposed to encrypt the data before outsourcing. To better protect data security, this paper makes the first attempt to formally address the problem of authorized data deduplication. Different from traditional deduplication systems, the differential privileges of users are further considered in duplicate check besides the data itself. We also present several new deduplication constructions supporting authorized duplicate check in a hybrid cloud architecture. Security analysis demonstrates that our scheme is secure in terms of the definitions specified in the proposed security model. As a proof of concept, we implement a prototype of our proposed authorized duplicate check scheme and conduct testbed experiments using our prototype. We show that our proposed authorized duplicate check scheme incurs minimal overhead compared to normal operations.

Explicit asymptotic formulas for the positions, widths, and strengths of resonances in Mie scattering

Abstract: Explicit asymptotic formulas are derived for the positions, widths, and strengths of the morphology-dependent resonances in Mie scattering. These formulas are compared with numerical data and found to be highly accurate, especially for the low-order resonances most relevant to nonlinear processes. They permit the interpretation of experimental data on light scattering from microdroplets without resorting to the full apparatus of the Mie scattering formalism.