Showing papers by "National Cheng Kung University published in 1995"

Incidence of Internal Cancers and Ingested Inorganic Arsenic: A Seven-Year Follow-up Study in Taiwan

Abstract: In order to elucidate the dose-response relationship between ingested inorganic arsenic and internal cancers, a total of 263 patients with blackfoot disease and 2293 healthy residents in the endemic area of arseniasis were recruited and followed up for 7 years. The information on consumption of high-arsenic artesian well water, sociodemographic characteristics, life-style and dietary habits, and personal and family history of cancers was obtained through standardized interviews. The occurrence of internal cancers among study subjects was determined through annual health examinations, home visit personal interviews, household registration data checks, and national death certification and cancer registry profile linkages. A dose-response relationship was observed between the long-term arsenic exposure from drinking artesian well water and the incidence of lung cancer, bladder cancer, and cancers of all sites combined after adjustment for age, sex, and cigarette smoking through Cox's proportional hazards regression analysis. Blackfoot disease patients had a significantly increased cancer incidence after adjustment for cumulative arsenic exposure.

Combination voltage-controlled and current-controlled PWM inverters for UPS parallel operation

Abstract: In this paper, a scheme of combination of voltage-controlled and current-controlled PWM inverters for parallel operation of a single-phase uninterruptible power supply (UPS) is proposed. The voltage-controlled PWM inverter (VCPI) unit as a master is developed to keep a constant sinusoidal wave output voltage. The current-controlled PWM inverter (CCPI) units are operated as slave controlled to track the distributive current. The power distribution center (PDC) performs the function of distributing the output current of each active unit. In this proposed scheme of parallel operation, each of the units can be designed as nearly independent, and the CCPI units do not need a PLL circuit for synchronization. As a result, the parallel operation of UPS is easy to implement and to expand system capacity. For the purpose of illustration, the system, including three single-phase units which operate in parallel, is analyzed and experimental results are given. >

Source number estimators using transformed Gerschgorin radii

Abstract: We introduce effective uses of Gerschgorin radii of the unitary transformed covariance matrix for source number estimation. There are two approaches, likelihood and heuristic, used for developing the detection criteria. The likelihood approach combines the Gerschgorin radii to the well-known source number detectors and improves their detection performances for Gaussian and white noise processes. It is verified that the Gerschgorin likelihood estimators (GLE) are consistent. The Gerschgorin AIC yields a consistent estimate and the Gerschgorin MDL criterion does not tend to underestimate for small or moderate data samples. The heuristic approach applying the Gerschgorin disk estimator (GDE) developed from the projection concept, overcomes the problem in cases of small data samples, an unknown noise model, and data dependency. Furthermore, the detection performances of both approaches through the suggested rotations and averaging can be further improved. Finally, the proposed and existing criteria are evaluated in various conditions by using simulated and measured experimental data. >

Detection of CYP2C9 polymorphism based on the polymerase chain reaction in Chinese.

Abstract: Cytochrome P450 (CYP) 2C9 catalyses the metabolism of a wide range of drugs Previous studies have shown the differences in the amino acid composition among CYP2C9 variants at Cys144/Arg, Tyr358/Cys, Leu359/Ile, and Gly417/Asp PCR-endonuclease digestion methods have been developed to detect these four possible polymorphisms The T416-->C mutation in exon 3 of CYP2C9 (Cys144-->Arg) creates an Ava II site In the 135 subjects we tested, all leukocyte DNA samples showed a complete Ava II digestion indicating homozygous C416 (Arg144) A Tyr358-->Cys mutation will create a Nsi I site at codon 1057-1063 in exon 7 In 40 subjects tested, all samples showed negative results DNA sequencing on a few samples showed Tyr358Ile359 A mismatched PCR primer pair was then designed to detect codon C1061-->A (Leu359-->Ile) mutation In 115 subjects tested, 111 samples showed a complete Nsi I digestion (Ile359) and four samples showed heterozygous results Another mismatched PCR primer pair was used to confirm the C1061 codon in heterozygous subjects The four heterozygous subjects showed partial digestion with endonuclease Kpn I, which confirmed the heterozygous Ile/Leu at amino acid 359 The G1236-->A mutation in exon 8 of CYP2C9 (Gly417-->Asp) creates a Hph I site In all 46 subjects, homozygous G1236 (Gly417) was found Most Chinese subjects actually have Arg144 Tyr358 Ile359 Gly417 in CYP2C9 as previously reported human-2 Furthermore, we found an A-->T (+12 position in intron 2) mutation in our CYP2C9 sequencing process The mutation creates a NIa III site(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of ARMAX model for short term load forecasting: an evolutionary programming approach

Abstract: This paper proposes a new evolutionary programming (EP) approach to identify the autoregressive moving average with exogenous variable (ARMAX) model for one day to one week ahead hourly load demand forecasts. Typically, the surface of forecasting error function possesses multiple local minimum points. Solutions of the traditional gradient search based identification technique therefore may stall at the local optimal points which lead to an inadequate model. By simulating natural evolutionary process, the EP algorithm offers the capability of converging towards the global extremum of a complex error surface. The developed EP based load forecasting algorithm is verified by using different types of data for practical Taiwan power (Taipower) system and substation load as well as temperature values. Numerical results indicate the proposed EP approach provides a method to simultaneously estimate the appropriate order and parameter values of the ARMAX model for diverse types of load data. Comparisons of forecasting errors are made to the traditional identification techniques.

Aeromonas Bacteremia: Review of 59 Episodes

Abstract: Fifty-nine episodes of bacteremia due to Aeromonas species occurred within a 5-year period in one medical center in southern Taiwan. Underlying diseases in the 58 patients included hepatic cirrhosis (36%) and cancer (24%). Patients with aeromonas bacteremia more often had underlying hepatic cirrhosis than did those with bacteremia due to other gram-negative bacilli. Males (67%) outnumbered females. The cases appeared to cluster in the summer and fall months. Thirty-two percent were polymicrobial infections; often the Aeromonas pathogens were accompanied by other gram-negative bacilli. Aeromonas hydrophila was the most common species isolated (69%). In addition to fever, hypotension and jaundice were the common clinical manifestations of aeromonas sepsis. In cirrhotic patients, spontaneous bacterial peritonitis, altered mental status, and jaundice were most common, and aeromonas bacteremia in such patients was monomicrobial and community-acquired more often than in noncirrhotic patients. In vitro aeromonads were generally susceptible to aminoglycosides, cefuroxime, the third-generation cephalosporins, and quinolones. The overall crude fatality rate was 36%. Predictors of fatal outcome for cirrhotic patients included spontaneous bacterial peritonitis, hypotension on admission, diabetes mellitus, and high Pugh scores.

Adverse life events and breast cancer : case-control study

Abstract: Objective : To investigate the strength of association between past life events and the development of breast cancer. Design : Case-control study. A standardised life events interview and rating was administered before a definitive diagnosis. Setting : Breast Cancer Screening Assessment Unit and surgical outpatient clinics at King9s College Hospital, London. Subjects : 119 consecutive women aged 20-70 who were referred for biopsy of a suspicious breast lesion. Main outcome measures : Odds ratio of the risk of developing breast cancer after life events in the preceding five years after adjustment for confounders. Results : 41 women were diagnosed as having malignant disease while the remainder had benign conditions. Severe life events increased the risk of breast cancer. The crude odds ratio was 3.2 (95% confidence interval 1.35 to 7.6). After adjustment for age and the menopause and other potential confounders this rose to 11.6 (3.1 to 43.7). Multiple logistic regression analysis showed that all severe events and coping with the stress of adverse events by confronting them and focusing on the problems significantly predicted a diagnosis of breast cancer. Non-severe life events and long term difficulties had no significant association. Conclusion : These findings suggest an aetiological association between life stress and breast cancer.

Effects of Exercise Training and Deconditioning on Platelet Function in Men

Abstract: Platelets play an important role in the pathogenesis of cardiovascular disease. It has also been noticed that regular exercise can reduce the risk of cardiovascular disease. This is the first study to demonstrate that endurance exercise training may suppress platelet adhesiveness and aggregation and that deconditioning may reverse the training effects. Healthy male sedentary subjects were randomly divided into control and training groups. The trained men were trained on a bicycle ergometer at about 60% of maximal oxygen consumption for 30 minutes per day, 5 days per week for 8 weeks, then deconditioned for 12 weeks. During the experimental period, blood samples of the trained subjects were collected before and immediately after a progressive exercise test every 4 weeks. The same experiments were applied to the controls at the beginning of this study and 8 weeks thereafter. A tapered parallel-plate chamber was used to assess platelet adhesiveness. Platelet aggregation induced by ADP was evaluated by the percentage of reduction in single platelet count. Our results showed that (1) platelet adhesiveness and aggregability were increased by short-term strenuous exercise in both control and trained groups, but the enhancement of platelet aggregability was decreased after exercise training in the trained subjects; (2) at rest and immediately after strenuous exercise, platelet adhesiveness and aggregability were decreased by training, whereas they were unchanged in the control group; and (3) deconditioning reversed the training effects on resting and postexercise platelet adhesiveness and aggregability back to the pretraining state. These results suggest that platelet adhesiveness and aggregability may be depressed by exercise training but be reversed back to the pretraining state after deconditioning.

Schwann Cell Properties: 3. C-fos Expression, bFGF Production, Phagocytosis and Proliferation During Wallerian Degeneration

Abstract: The role of Schwann cells (SC) during Wallerian degeneration has been controversial. The consensus opinion is that monocytes/macrophages are mainly responsible for myelin removal although SC were shown to phagocytose myelin in vitro and in vivo. In the present study, we correlate proto-oncogene expression with phenotypic changes in SC during Wallerian degeneration using immunohistochemistry and electron microscopy. The proliferative cells are labeled with proliferative cell nuclear antigen (PCNA), and macrophages are labeled with ED1 macrophage marker. We demonstrate c-fos expression in SC at the onset of axon disintegration 12 hours post-axotomy followed by expression of ED1, basic fibroblast growth factor (bFGF) and PCNA after 1 day. The myelin sheath fragments at the nodal region and forms ellipsoids. Schwann cells move to internodes and undergo nuclear and cytoplasmic hypertrophy; they phagocytose myelin ellipsoids with thick vimentin-rich processes and undergo mitosis. Resident macrophages express c-fos and phagocytose myelin debris sequestered into endoneurium by SC after 3 days, but they do not enter the tube until the fifth day. We believe that SC are induced by signals from injured axons to express c-fos which activates downstream genes that lead to the acquisition of phagocytic and proliferative activities. Myelin debris processed by SC may act as an inducer and a chemoattractant for resident macrophages. Cytokines produced by macrophages may stimulate SC proliferation and production of neurotrophic factors.

Inhibition of intestinal P-glycoprotein and effects on etoposide absorption.

Abstract: P-glycoprotein (Pgp) actively pumps a number of antineoplastic drugs, such as etoposide, out of cancer cells and causes multidrug resistance. Pgp is also expressed at the brush-border membrane of the small intestine under normal physiological conditions. We hypothesized that inhibition of intestinal Pgp might decrease the efflux of etoposide from the blood into the intestinal lumen, thereby, increasing the bioavailability of etoposide. The absorption of etoposide was studied using everted gut sacs prepared from rat jejunum and ileum. The addition of C219, a monoclonal antibody of Pgp, at 100 ng/ml or of 0.2 M 5′-adenylylimidodiphosphate, a nonhydrolyzable adenosine triphosphate (ATP) analog, increased the absorption of etoposide. Quinidine, an antiarrythmic agent, has been demonstrated to circumvent multidrug resistance in cell lines, possibly by interfering with Pgp function. Adding quinidine at 1 mg/ml to the everted gut sac increased the absorption of etoposide. In vivo absorption of etoposide was also studied by intraluminal perfusion of the drug in the small intestine of anesthetized rats. Intravenous infusion of quinidine at either 1 or 2 mg/h increased the serum level of etoposide in a dose-dependent manner. Intravenous infusion of etoposide at 0.2 mg/h resulted in luminal exsorption of the drug in the small intestine. The intestinal clearance of etoposide was 41.7 ± 7.2 ml kg−1, which decreased to 18.4 ± 3.9 ml kg−1 with the infusion of quinidine at 1 mg/h. The present data confirm that intestinal Pgp mediates the efflux of etoposide and that the use of Pgp-inhibiting agents such as quinidine may increase the bioavailability of etoposide.

A Modified Low-Reynolds-Number Turbulence Model Applicable to Recirculating Flow in Pipe Expansion

Abstract: A modified low-Reynolds-number k-e turbulence model is developed in this work. The performance of the proposed model is assessed through testing with fully developed pipe flows and recirculating flow in pipe expansion. Attention is specifically focused on the flow region around the reattachment point. It is shown that the proposed model is capable of correctly predicting the near-wall limiting flow behavior while avoiding occurrence of the singular difficulty near the reattachment point as applying to the recirculating flow in sudden-expansion pipe.

A Comparative Analysis of Quality Practice in Manufacturing Firms in the U.S. and Taiwan

Abstract: The aim of this paper is to determine if there is a causal relationship between multivariate constructs for quality (i.e., customer satisfaction, employee satisfaction, and employee service quality) and organizational performance. The presence of such relationships, as well as the identification of key indicators within each quality construct for different types of firms, are explored in this empirical study on the perceptions of middle managers in Taiwan and the United States. The study found a significant causal relationship between the quality constructs and organizational performance. These relationships are different, however, for the four types of firms based on age and size. Also, within the same firm types, there are differences among countries. For example, for older firms, Taiwanese managers tend to perceive customer satisfaction as the most important quality construct in improving organizational performance, while U.S. managers tend to perceive employee satisfaction as the most important. For younger firms, U.S. managers perceive customer satisfaction as influencing organizational performance, while Taiwanese managers perceive both customer satisfaction and employee satisfaction as doing so. A further breakdown of the quality constructs identified the key indicators within each construct that separates “better performers'’from “lesser performers'’in both countries for the four types of firms. These indicators are dissimilar, thus suggesting that focus on quality constructs may lead to improvements in organizational performance by focusing on different indicators in different environments. These results have implications for the adoption and implementation of quality practices in different countries.

Growth abnormalities in the population exposed in utero and early postnatally to polychlorinated biphenyls and dibenzofurans.

Abstract: This article reviews the findings in children exposed to various levels of polychlorinated biphenyls (PCBs) and related compounds in utero and early postnatally. Yu-Cheng ("oil-disease") mothers we...

Combined techniques of singular value decomposition and vector quantization for image coding

Abstract: The combination of singular value decomposition (SVD) and vector quantization (VQ) is proposed as a compression technique to achieve low bit rate and high quality image coding. Given a codebook consisting of singular vectors, two algorithms, which find the best-fit candidates without involving the complicated SVD computation, are described. Simulation results show that the proposed methods are better than the discrete cosine transform (DCT) in terms of energy compaction, data rate, image quality, and decoding complexity. >

Multiscale corner detection by using wavelet transform

Abstract: A multiscale corner detection algorithm based on the wavelet transform of contour orientation is proposed. It can utilize both the information of the local extrema and modulus of transform results to detect corners and arcs effectively. The ramp-width of contour orientation profile, which can be computed using the transformed modulus of two scales, reveals the difference between corner and arc and is utilized in the determination of corner points. The experimental results have shown that the detector is more effective than both the single- and multiple-scale detectors. They also demonstrate that the detector is insensitive to boundary noise. In addition, the proposed method is more efficient than the other multiscale corner detector because it operates on fewer number of scales, which can be implemented by a fast transform algorithm. >

Changes in phases and crystallinity of plasma-sprayed hydroxyapatite coatings under heat treatment: a quantitative study.

Abstract: With three kinds of plasma-sprayed hydroxyapatite coatings (HACs) prepared, the objectives of this study were (1) to establish the calibration methods for quantitatively measuring the concentration of impurity phases and the degree of crystallinity of the HACs, and (2) to explore the effects of postheat treatments at various temperatures in vacuo on the changes of phases and crystallinity of the HACs. By the internal standard method used, the concentrations of impurity phases, such as alpha-TCP, beta-TCP, and TP, of the assprayed HACs were significantly higher than those measured by the direct intensity-ratio method, and the CaO phase was lower than the direct intensity-ratio method. When the HACs were heat treated in the temperature interval 630-850 degrees C, the concentrations of impurity phases obviously decreased, and the coating crystallinity apparently increased. After annealing at 850 degrees C, an HAC consisting of at least 95% crystallinity with few impurity phases was obtained. As the annealing temperatures in the interval 850-1000 degrees C were applied, however, the HA phase seriously decomposed, resulting in the appearance of a large number (higher than 20 wt%) of impurity phases in the HACs. This work suggests that the optimum heat treatment conditions in vacuo for maximizing crystallinity and minimizing impurity phases of the HACs do not occur at the same temperature.

The influences of plasma spraying parameters on the characteristics of hydroxyapatite coatings: a quantitative study

Abstract: All laboratory-made plasma-sprayed hydroxylapatite coatings (HACs) were found to undergo, to different degrees, changes in phase composition, crystallinity, morphology and roughness dependent on plasma spraying parameters (PSPs) The PSPs, which were systematically varied, included the plasma atmosphere, the spraying current and the stand-off distance Through the determinations of the concentration of impurity phase (CIP) and the index of crystallinity (IOC), the extent of phase purity and the degree of crystallinity of HACs were quantitatively assessed, respectively Coatings consisting of at least 50% (IOC>50%) of the original crystalline structure and almostly 95% (CIP<5%) apatite with barely detectable extra phases were obtained The microstructure of HACs exhibited great deviations both in morphology from molten to partial molten state and in roughness from coating of high irregularity (R a=1448μm) to a smoother (R a=446 μm) one, dominantly influenced by the spraying atmosphere As the terms of CIP and IOC are defined and established, the biological responses related to phase purity and crystallinity of HACs can be further evaluated in vitro and in vivo

Applicability of perturbative QCD to B-->D decays.

Abstract: We examine the applicability of perturbative QCD to {ital B} meson decays into {ital D} mesons. We find that the perturbative QCD formalism, which includes Sudakov effects at intermediate energy scales, is applicable to the semileptonic decay {ital B}{r_arrow}{ital Dl}{nu}, when the {ital D} meson recoils fast. Following this conclusion, we analyze the two-body nonleptonic decays {ital B}{r_arrow}{ital D}{pi} and {ital B}{r_arrow}{ital DD}{sub {ital s}}. By comparing our predictions with experimental data, we extract the matrix element {vert_bar}{ital V}{sub {ital c}{ital b}}{vert_bar}=0.044.

Cubic to Tetragonal Phase Transformation of Ultrafine BaTiO3 Crystallites at Room Temperature

Abstract: The critical crystallite size for the cubic (c-) to tetragonal (t-) phase transformation of ultrafine BaTiO3 crystallites was examined. Crystallites were prepared by calcination of barium titanyl oxalate tetrahydrate (BTOT) at various temperatures as to obtain crystallites with different sizes. The c- BaTiO3 crystallite which is thermodynamically considered as a high-temperature form can exist at room temperature if the crystallite is smaller than certain size. The critical size for the c→t phase transformation is ~30 nm. The size may become larger if the crystallite suffers higher lattice strain which can be induced by different powder preparation methods.

Spontaneous rupture of hepatocellular carcinoma : a review of 141 Taiwanese cases and comparison with nonrupture cases

Abstract: We reviewed the records and statistics of 560 patients hospitalized with hepatocellular carcinoma (HCC) over a 5-year period. One hundred and forty-one patients (26%) had spontaneous rupture of their HCCs. Different characteristics of the rupture (R) and nonrupture (NR) groups were compared; there were statistically significant differences (p < 0.05) in the size of the tumor (R, 9.83 +/- 4.36 cm, and NR, 7.67 +/- 4.01 cm; p < 0.0001), and the minimal thickness of peritumor liver parenchyma (R, 0.03 +/- 0.20 cm, and NR, 0.30 +/- 0.70 cm; p < 0.001), the presence of the ?hump sign? (R, 87.8%, and NR, 45.7%; p < 0.0001), and the minimal thickness of peritumor liver parenchyma (R, 0.03 +/- 0.20 cm, and NR, 0.30 +/- 0.70 cm; p < 0.001). The percentage of left-lobe tumors was significantly higher in the rupture group than in the nonrupture group (p < 0.05). In addition, the Child-Pugh's score and serum transaminase levels were higher, and the prothrombin times more prolonged, in the rupture group. Factors that were not statistically significant included sex, age, etiology of cirrhosis, platelet count, portal vein thrombosis, and the presence of a varix. Multivariate logistic regression analysis indicated that the tumor size, the presence of a hump sign, and the Pugh's score correlated the best with HCC rupture (p < 0.05). Ninety-four patients from the rupture group died during hospitalization. The mortality rate was 66.7%. We conclude that (a) spontaneous rupture of HCC is a likely sequel of progressive expansion of tumor that finally protrudes outside the liver surface and hemorrhages, (b) left-lobe tumor presents a higher risk of rupture, and (c) portal hypertension does not play a major role in the pathogenesis of tumor rupture.