Showing papers by "The Chinese University of Hong Kong published in 2001"
TL;DR: In this article, the authors test a theoretical framework relating four major corporate governance attributes with the extent of voluntary disclosure provided by listed firms in Hong Kong, including the proportion of independent directors to total number of directors on the board, the presence of a voluntary audit committee, the existence of a dominant personalities (CEO/Chairman duality), and the percentage of family members on the boards.
1,192 citations
TL;DR: There is a significantly elevated RR of severe liver disease in persons who are coinfecting with HIV and HCV, which has important implications for timely diagnosis and consideration of treatment in coinfected persons.
Abstract: Studies have shown that rates of liver disease are higher in persons who are coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) than they are in persons with HCV alone, but estimates of risk vary widely and are based on data for dissimilar patient populations. We performed a meta-analysis to quantify the effect of HIV coinfection on progressive liver disease in persons with HCV. Eight studies were identified that included outcomes of histological cirrhosis or decompensated liver disease. These studies yielded a combined adjusted relative risk (RR) of 2.92 (95% confidence interval [CI], 1.70-5.01). Of note, studies that examined decompensated liver disease had a combined RR of 6.14 (95% CI, 2.86-13.20), whereas studies that examined histological cirrhosis had a pooled RR of 2.07 (95% CI, 1.40-3.07). There is a significantly elevated RR of severe liver disease in persons who are coinfected with HIV and HCV. This has important implications for timely diagnosis and consideration of treatment in coinfected persons.
965 citations
TL;DR: In this article, a generic framework for analyzing innovation systems, anchored around five fundamental activities (R&D, implementation, end-use, education, linkage) is proposed, focusing on the performance implications of a system's structure and dynamics.
719 citations
TL;DR: The generalized likelihood ratio statistics are shown to be general and powerful for nonparametric testing problems based on function estimation and can even be adaptively optimal in the sense of Spokoiny by using a simple choice of adaptive smoothing parameter.
Abstract: Likelihood ratio theory has had tremendous success in parametric inference, due to the fundamental theory of Wilks. Yet, there is no general applicable approach for nonparametric inferences based on function estimation. Maximum likelihood ratio test statistics in general may not exist in nonparametric function estimation setting. Even if they exist, they are hard to find and can not; be optimal as shown in this paper. We introduce the generalized likelihood statistics to overcome the drawbacks of nonparametric maximum likelihood ratio statistics. A new S Wilks phenomenon is unveiled. We demonstrate that a class of the generalized likelihood statistics based on some appropriate nonparametric estimators are asymptotically distribution free and follow chi (2)-distributions under null hypotheses for a number of useful hypotheses and a variety of useful models including Gaussian white noise models, nonparametric regression models, varying coefficient models and generalized varying coefficient models. We further demonstrate that generalized likelihood ratio statistics are asymptotically optimal in the sense that they achieve optimal rates of convergence given by Ingster. They can even be adaptively optimal in the sense of Spokoiny by using a simple choice of adaptive smoothing parameter. Our work indicates that the generalized likelihood ratio statistics are indeed general and powerful for nonparametric testing problems based on function estimation.
676 citations
TL;DR: It is shown that the closed-loop system resulting from the control law can maintain its local finite-time stability regardless of some nonlinear perturbations, indicating that the law actually applies to a large class of nonlinear second order systems.
Abstract: Studies the problem of finite-time output feedback stabilization for the double integrator system. A class of output feedback controllers that can achieve global finite-time stability for the double integrator system are constructed based on a "finite-time separation principle." Furthermore, it is shown that the closed-loop system resulting from our control law can maintain its local finite-time stability regardless of some nonlinear perturbations. Thus, our control law actually applies to a large class of nonlinear second order systems.
652 citations
TL;DR: Among patients with H. pylori infection and a history of upper gastrointestinal bleeding who are taking low-dose aspirin, the eradication of H.pylori is equivalent to treatment with omeprazole in preventing recurrent bleeding.
Abstract: Background Many patients who have had upper gastrointestinal bleeding continue to take low-dose aspirin for cardiovascular prophylaxis or other nonsteroidal antiinflammatory drugs (NSAIDs) for musculoskeletal pain. It is uncertain whether infection with Helicobacter pylori is a risk factor for bleeding in such patients. Methods We studied patients with a history of upper gastrointestinal bleeding who were infected with H. pylori and who were taking low-dose aspirin or other NSAIDs. We evaluated whether eradication of the infection or omeprazole treatment was more effective in preventing recurrent bleeding. We recruited patients who presented with upper gastrointestinal bleeding that was confirmed by endoscopy. Their ulcers were healed by daily treatment with 20 mg of omeprazole for eight weeks or longer. Then, those who had been taking aspirin were given 80 mg of aspirin daily, and those who had been taking other NSAIDs were given 500 mg of naproxen twice daily for six months. The patients in each group w...
647 citations
TL;DR: Data in Chinese patients with chronic hepatitis B show enhanced seroconversion rates with extended lamivudine treatment, and up to two thirds of patients with moderately elevated pretreatment ALT achieved HBeAg serconversion after 3 years of therapy.
633 citations
TL;DR: In this paper, the authors determine the factor structure of safety climate within a road construction organization using a modified version of the safety climate questionnaire (SCQ), and investigate the relationship between safety climate and safety performance.
535 citations
TL;DR: The authors analyzed the degree to which the segregation between rural migrants and urban residents has occurred from the point of view of occupational segregation and wage differentials in terms of occupational attainment and wages.
523 citations
TL;DR: In this paper, the authors introduce nonlinear regularized wavelet estimators for estimating nonparametric regression functions when sampling points are not uniformly spaced, and obtain Oracle inequalities and universal thresholding parameters for a large class of penalty functions.
Abstract: In this paper, we introduce nonlinear regularized wavelet estimators for estimating nonparametric regression functions when sampling points are not uniformly spaced. The approach can apply readily to many other statistical contexts. Various new penalty functions are proposed. The hard-thresholding and soft-thresholding estimators of Donoho and Johnstone are specific members of nonlinear regularized wavelet estimators. They correspond to the lower and upper envelopes of a class of the penalized least squares estimators. Necessary conditions for penalty functions are given for regularized estimators to possess thresholding properties. Oracle inequalities and universal thresholding parameters are obtained for a large class of penalty functions. The sampling properties of nonlinear regularized wavelet estimators are established and are shown to be adaptively minimax. To efficiently solve penalized least squares problems, nonlinear regularized Sobolev interpolators (NRSI) are proposed as initial estimators, wh...
520 citations
Columbia University1, Rutgers University2, Ohio State University3, University of Maryland, College Park4, Hong Kong Baptist University5, The Chinese University of Hong Kong6, University of Osnabrück7, Towson University8, University of North Carolina at Greensboro9, University of North Carolina at Chapel Hill10
TL;DR: The authors found that the tendency for people to respond less favorably (i.e., with lower organizational commitment) to lower levels of voice was greater in low power distance cultures (United States and Germany) than in high power distance (People's Republic of China, Mexico, and Hong Kong) and found a similar interactive effect of voice and people's power distance beliefs on employees' work attitudes and job performance.
TL;DR: It is demonstrated that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechin to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.
Abstract: Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3'-gallate (TF2B) and theaflavin-3,3'-digallate (TF3). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu(+2)-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF3 > ECG > EGCG > or = TF2B > or = TF2A > TF1 > or = EC > EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu(+2)-mediated LDL oxidation at concentrations of 5-40 micromol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.
TL;DR: The findings add to this body of evidence, which together suggest an adverse impact of antepartum psychological morbidity on maternal and neonatal well-being, and suggest that growth retardation, premature delivery, and epidural analgesia may be associated with adverse obstetric and Neonatal outcomes.
Abstract: Objective The purpose of this study was to examine if depressive symptomatology in pregnancy is associated with adverse obstetric and neonatal outcomes. Method In a prospective observational study, 959 women were followed up longitudinally from early pregnancy to postpartum. The level of depression was measured at baseline (first antepartum visit) and in late pregnancy using the Beck Depression Inventory (BDI). Adverse obstetric and neonatal outcomes were recorded at delivery. Results Depression in late pregnancy was associated with increased risk of epidural analgesia (33% vs. 19%, p =.01, adjusted RR = 2.56, 95% CI 1.24-5.30), operative deliveries (caesarean sections and instrumental vaginal deliveries) (39% vs. 27%, p =.02, adjusted RR = 2.28, 95% CI 1.15-4.53), and admission to neonatal care unit (24% vs. 19%, p =.03, adjusted RR = 2.18, 95% CI 1.02-4.66). These effects remained significant even when controlled for potential confounders, such as antepartum complications. Conclusion Previous studies have shown that antepartum anxiety or stress was associated with growth retardation, premature delivery, and epidural analgesia. Our findings add to this body of evidence, which together suggest an adverse impact of antepartum psychological morbidity on maternal and neonatal well-being.
TL;DR: Thoracic paravertebral blocks can be used to provide analgesia for unilateral trunk surgeries and ultrasound-guided approaches for needle tip placement and injection monitoring are described.
Abstract: Thoracic paravertebral blocks can be used to provide analgesia for unilateral trunk surgeries. Ultrasound-guided approaches for needle tip placement and injection monitoring are described. Anterior displacement of the pleura occurs with injection of local anesthetic in the paravertebral space.
TL;DR: It is proposed that allergic asthma is characterized by an elevation of both proinflammatory and Th2 cytokines, and the significantly lower ratio of Th1/Th2 cells confirms a predominance of Th2 cells response in allergic asthma.
Abstract: Allergen-reactive T helper type-2 (Th2) cells and proinflammatory cytokines have been suggested to play an important role in the induction and maintenance of the inflammatory cascade in allergic asthma. We compared the plasma concentrations of novel proinflammatory cytokines IL-17 and IL-18, other proinflammatory cytokines IL-6 and IL-12, Th2 cytokines IL-10 and IL-13, and intracellular interferon-γ (IFN-γ) and IL-4 in Th cells of 41 allergic asthmatics and 30 sex- and age-matched health control subjects. Plasma cytokines were measured by enzyme-linked immunosorbent assay. Intracellular cytokines were quantified by flow cytometry. Plasma IL-18, IL-12, IL-10, IL-13 concentrations were significantly higher in allergic asthmatic patients than normal control subjects (IL-18: median 228·35 versus 138·72 pg/ml, P 0·05). Consequently, the Th1/Th2 cell ratio was significantly higher in normal subjects than asthmatic patients (29·6 versus 8·38%, P < 0·001). We propose that allergic asthma is characterized by an elevation of both proinflammatory and Th2 cytokines. The significantly lower ratio of Th1/Th2 cells confirms a predominance of Th2 cells response in allergic asthma.
TL;DR: The stability study demonstrated that GTC was stable in water at room temperature and suggested that other ingredients used in production of tea drinks might interact with GTC and affect its stability.
Abstract: Green tea cateachins (GTC). namely (-) epicatechin (EC), (-) epicatechin gallate (ECG), (-) epigallocatechin (EGC), and (-) epigallocatechin gallate (EGCG), have been studied extensively for their wide-ranging biological activities. The goal of the present study was to examine the stability of GTC as a mixture under various processing conditions. The stability study demonstrated that GTC was stable in water at room temperature. When it was brewed at 98 degrees C for 7 h, longjing GTC degraded by 20%. When longjing GTC and pure EGCG were autoclaved at 120 degrees C for 20 min, the epimerization of EGCG to (-) gallocatechin gallate (GCG) was observed. The relatively high amount of GCG found in some tea drinks was most likely the epimerization product of EGCG during autoclaving. If other ingredients were absent, the GTC in aqueous solutions was pH-sensitive: the lower the pH, the more stable the GTC during storage. When it was added into commercially available soft drinks or sucrose solutions containing citric acid and ascorbic acid, longjing GTC exhibited varying stability irrespective of low pH value. This suggested that other ingredients used in production of tea drinks might interact with GTC and affect its stability. When canned and bottled tea drinks are produced, stored, and transported, the degradation of GTC must be taken into consideration.
TL;DR: It is postulated that in fatal human infections with this avian subtype, initial virus replication in the respiratory tract triggers hypercytokinemia complicated by the reactive hemophagocytic syndrome.
Abstract: Eighteen cases of human influenza A H5N1 infection were identified in Hong Kong from May to December 1997. Two of the six fatal cases had undergone a full post-mortem which showed reactive hemophagocytic syndrome as the most prominent feature. Other findings included organizing diffuse alveolar damage with interstitial fibrosis, extensive hepatic central lobular necrosis, acute renal tubular necrosis and lymphoid depletion. Elevation of soluble interleukin-2 receptor, interleukin-6 and interferon-gamma was demonstrated in both patients, whereas secondary bacterial pneumonia was not observed. Virus detection using isolation, reverse transcription-polymerase chain reaction and immunostaining were all negative. It is postulated that in fatal human infections with this avian subtype, initial virus replication in the respiratory tract triggers hypercytokinemia complicated by the reactive hemophagocytic syndrome. These findings suggest that the pathogenesis of influenza A H5N1 infection might be different from that of the usual human subtypes H1-H3.
TL;DR: In this article, the ultimate ownership and control of 5,232 corporations in 13 Western European countries were analyzed and found that firms are either widely held (36.93 percent) or family controlled (44.29 percent).
Abstract: We analyze the ultimate ownership and control of 5,232 corporations in 13 Western European countries. Firms are typically widely held (36.93 percent) or family controlled (44.29 percent). Widely-held firms are more important in the U.K. and Ireland, family-controlled firms in continental Europe. Financial and large firms are more likely to be widely-held, while non-financial and small firms are more likely to be family-controlled. State control is important for larger firms in certain countries. Dual class shares and pyramids are used to enhance the control of the largest shareholders, but overall there are significant discrepancies between ownership and control in only a few countries.
TL;DR: Standardization in plasma-processing protocols is needed for maternal plasma DNA analysis, especially for quantification of total DNA in maternal plasma and day-to-day fluctuation of fetal and total DNAIn maternal plasma.
Abstract: Background: Recently, apoptotic cells have been found in plasma obtained by centrifugation of blood from pregnant women, raising the question of what constitutes plasma and whether plasma is truly cell free. We compared the effects of different blood-processing protocols on the quantification, DNA composition, and day-to-day fluctuation of fetal and total DNA in maternal plasma.
Methods: Blood samples were collected from healthy pregnant women. The blood sample from each individual was simultaneously processed by different means, including the following: Percoll separation, centrifugation, microcentrifugation, and filtration. The resulting plasma aliquots were subjected to real-time quantitative amplification of the β- globin (for total DNA) and SRY (for fetal DNA) genes. The differences in the β- globin and SRY DNA concentrations and the degree of variation between the various plasma aliquots were assessed statistically.
Results: Different protocols of blood processing significantly affected the quantification and the day-to-day fluctuation of total ( P <0.001), but not fetal (quantification, P = 0.336; fluctuation, P = 0.206), DNA in maternal plasma. The quantitative difference could be attributed to the fact that efficacies of different protocols for generating cell-free plasma vary. Processing blood samples by centrifugation followed by filtration or microcentrifugation is effective in producing cell-free plasma.
Conclusions: Standardization in plasma-processing protocols is needed for maternal plasma DNA analysis, especially for quantification of total DNA in maternal plasma. Such preanalytic factors may also affect other applications of plasma DNA analysis.
TL;DR: The structural path model shows the important factors that influence the intention to use the Internet/WWW as well as interrelationships between the factors and shows that the proposed model provides a better fit than the original model.
TL;DR: A novel method for preparing highly photoactive nano-sized TiO2 photocatalysts with anatase and brookite phases has been developed by hydrolysis of titanium tetraisoproproxide in pure water or a 1:1 EtOH-H2O solution under ultrasonic irradiation.
TL;DR: There is preliminary evidence that changes in serum AFP may be a more accurate and sensitive way of determining the degree of response to treatment than conventional imaging procedures that rely on physical determination of tumor size.
TL;DR: Results show that neural networks are valuable tools for modeling and forecasting nonlinear time series while traditional linear methods are not as competent for this task.
TL;DR: Evidence provided by cross sectional and longitudinal studies suggests that TCC exercise has beneficial effects on cardiorespiratory and musculoskeletal function, posture control capacity, and the reduction of falls experienced by the elderly.
Abstract: Objectives—To assess the characteristic eVects of Tai Chi Chuan (TCC) exercise on metabolism and cardiorespiratory response,andtomeasureitseVectoncardiorespiratory function, mental control, immune capacity, and the prevention of falls in elderly people. Design—A review of controlled experimental studies and clinical trials designed with one of two aims: either to assess physiological responses during the performance of TCC or to assess the impact of this exercise on general health and fitness. Main outcome measures—Metabolic rate, heart rate, blood pressure, ventilation, maximal oxygen uptake (V ~O2MAX), immune capacity, falls, and fall related factors. Subjects—A total of 2216 men and women. Results—Under review were 31 original studies, published in Chinese or English journals, that met the criteria for inclusion. Most of the papers written in Chinese had not been introduced into the Western literature. Nine of these studies showed that TCC can be classified as moderate exercise, as its does not demand more than 55% of maximal oxygen intake. When this form of exercise and others conducted at equal intensity were compared, TCC showed a significantly lower ventilatory equivalent (V ~E/V ~O2MAX). Evidence provided by cross sectional and longitudinal studies suggests that TCC exercise has beneficial eVects on cardiorespiratory and musculoskeletal function, posture control capacity, and the reduction of falls experienced by the elderly. Conclusions—TCC is a moderate intensity exercise that is beneficial to cardiorespiratory function, immune capacity, mental control, flexibility, and balance control; it improves muscle strength and reduces the risk of falls in the elderly. (Br J Sports Med 2001;35:148‐156)
TL;DR: It is concluded that there is moderate variation in the incidence of hip fracture among Asian countries, and the rates were highest in urbanized countries.
Abstract: The Asian Osteoporosis Study (AOS) is the first multicenter study to document and compare the incidence of hip fracture in four Asian countries. Hospital discharge data for the year 1997 were obtained for the Hong Kong SAR, Singapore, Malaysia and Thailand (Chiang Mai). The number of patients who were 50 years of age and older and who were discharged with a diagnosis of hip fracture (ICD9 820) was enumerated. The age-specific incidence rates were deduced and were directly adjusted to the US white population in 1989. The age-adjusted rates for men and women (per 100 000) are as follows: Hong Kong, 180 and 459; Singapore, 164 and 442; Malaysia, 88 and 218; Thailand, 114 and 289; compared with US White rates of 187 in men and 535 in women, published in 1989. We conclude that there is moderate variation in the incidence of hip fracture among Asian countries. The rates were highest in urbanized countries. With rapid economic development in Asia, hip fracture will prove to be a major public health challenge.
Journal Article•
TL;DR: Findings suggest that promoter hypermethylation may participate in the transcriptional inactivation of the RASSF1A gene in NPC and suggest that it is the critical target gene on chromosome 3p21.3 involved in the development of NPC.
Abstract: We have investigated the genetic and epigenetic changes of a newly isolated tumor suppressor gene on 3p213, RASSF1A, in nasopharyngeal carcinoma (NPC) Four xenografts, four cell lines and 21 primary tumors were examined Promoter hypermethylation of the 5'CpG island of RASSF1A was detected in 4 of 4 (100%) xenografts, in 3 of 4 (75%) cell lines, and in 14 of 21 (667%) primary tumors but not in the normal nasopharyngeal epithelia Mutations were found in 2 of 21 (95%) primary tumors In the cell lines and xenografts with extensive methylation, no RASSF1A gene expression was found After treatment with 5'-aza-2'deoxycytidine, reexpression and demethylation of the RASSF1A gene were detected in a NPC cell line These findings suggest that promoter hypermethylation may participate in the transcriptional inactivation of the RASSF1A gene in NPC The high incidence of RASSF1A alterations suggest that it is the critical target gene on chromosome 3p213 involved in the development of NPC
TL;DR: Of the physiologic variables used in the triage algorithms, the Motor Component of the Glasgow Coma Scale and systolic blood pressure had the strongest association with severe injury.
TL;DR: Placentas were obtained at delivery from 34 pregnancies complicated by preeclampsia and from 34 uncomplicated pregnancies and the incidence of apoptotic nuclei was significantly greater in the placentas from the pregnancies complicate by preeClampsia.
TL;DR: In this article, the authors derived uniform, first-and second-order a priori estimates for the elliptic and parabolic Hessian equations, and generalized these results for semilinear elliptic equations and the Monge-Ampere equation.
Abstract: By studying a negative gradient flow of certain Hessian functionals we establish the existence of critical points of the functionals and consequently the existence of ground states to a class of nonhomogenous Hessian equations. To achieve this we derive uniform, first- and second-order a priori estimates for the elliptic and parabolic Hessian equations. Our results generalize well-known results for semilinear elliptic equations and the Monge-Ampere equation. c 2001 John Wiley & Sons, Inc.
TL;DR: The present results suggest that part of the mechanism for cardiovascular protective effects of hawthorn fruit might also involve the direct protection to human LDL from oxidation or indirect protection via maintaining the concentration of alpha-tocopherol in human LDL.
Abstract: Hawthorn fruit extract has been shown to have many health benefits including being cardiovascular protective, hypotensive and hypocholesterolemic. The present study was carried out to characterize further the antioxidants of hawthorn fruit and their effect on the oxidation of human low density lipoprotein (LDL) and alpha-tocopherol. The dry hawthorn fruit was extracted successively with ether, ethyl acetate, butanol and water. The ethyl acetate fraction was only effective in inhibition of Cu(+2)-mediated LDL oxidation. The column chromatographic separation led to isolation of eight pure compounds; namely, ursolic acid, hyperoside, isoquercitrin, epicatechin, chlorogenic acid, quercetin, rutin and protocatechuic acid. All of these phenolic compounds, except ursolic acid, were protective to human LDL from Cu(+2)-mediated LDL oxidation. They were also effective in preventing the peroxy free radical-induced oxidation of alpha-tocopherol in human LDL. The inhibitory effect of these compounds on oxidation of LDL and alpha-tocopherol was dose-dependent at concentrations ranging from 5 to 40 µM. In addition, supplementation of 2% hawthorn fruit powder significantly elevated serum alpha-tocopherol by 18-20% in rats fed a 30% polyunsaturated canola oil diet, as compared with the control. The present results suggest that part of the mechanism for cardiovascular protective effects of hawthorn fruit might also involve the direct protection to human LDL from oxidation or indirect protection via maintaining the concentration of alpha-tocopherol in human LDL.