Showing papers by "National Cheng Kung University published in 2007"

Graphene-silica composite thin films as transparent conductors.

Abstract: Transparent and electrically conductive composite silica films were fabricated on glass and hydrophilic SiOx/silicon substrates by incorporation of individual graphene oxide sheets into silica sols followed by spin-coating, chemical reduction, and thermal curing. The resulting films were characterized by SEM, AFM, TEM, low-angle X-ray reflectivity, XPS, UV−vis spectroscopy, and electrical conductivity measurements. The electrical conductivity of the films compared favorably to those of composite thin films of carbon nanotubes in silica.

Role of ventilation in airborne transmission of infectious agents in the built environment - a multidisciplinary systematic review.

Abstract: There have been few recent studies demonstrating a definitive association between the transmission of airborne infections and the ventilation of buildings. The severe acute respiratory syndrome (SARS) epidemic in 2003 and current concerns about the risk of an avian influenza (H5N1) pandemic, have made a review of this area timely. We searched the major literature databases between 1960 and 2005, and then screened titles and abstracts, and finally selected 40 original studies based on a set of criteria. We established a review panel comprising medical and engineering experts in the fields of microbiology, medicine, epidemiology, indoor air quality, building ventilation, etc. Most panel members had experience with research into the 2003 SARS epidemic. The panel systematically assessed 40 original studies through both individual assessment and a 2-day face-to-face consensus meeting. Ten of 40 studies reviewed were considered to be conclusive with regard to the association between building ventilation and the transmission of airborne infection. There is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of infectious diseases such as measles, tuberculosis, chickenpox, influenza, smallpox and SARS. There is insufficient data to specify and quantify the minimum ventilation requirements in hospitals, schools, offices, homes and isolation rooms in relation to spread of infectious diseases via the airborne route. PRACTICAL IMPLICATION: The strong and sufficient evidence of the association between ventilation, the control of airflow direction in buildings, and the transmission and spread of infectious diseases supports the use of negatively pressurized isolation rooms for patients with these diseases in hospitals, in addition to the use of other engineering control methods. However, the lack of sufficient data on the specification and quantification of the minimum ventilation requirements in hospitals, schools and offices in relation to the spread of airborne infectious diseases, suggest the existence of a knowledge gap. Our study reveals a strong need for a multidisciplinary study in investigating disease outbreaks, and the impact of indoor air environments on the spread of airborne infectious diseases.

Acceptance and adoption of the innovative use of smartphone

Abstract: Purpose – The purpose of this study is to investigate human motivations affecting an adoption decision for smartphone among medical doctors and nurses.Design/methodology/approach – This study investigates smartphone users' perception based on users' perceived adoption under the self‐efficacy, technology acceptance model (TAM) and innovation attributes leading to an adoption attitude under innovation diffusion theory by providing research constructs for the domain of medical doctors and nurses, testing them with reliability and validity, and demonstrating their distinctiveness with hypothesis testing.Findings – The results indicate that behavioral intention to use was largely influenced by perceived usefulness (PU) and attitude toward using smartphone. PU and perceived ease of use positively determine attitude toward using smartphone.Research limitations/implications – For researchers, this study shows the possible and valuable adaptation of TAM constructs into the smartphone acceptance of doctors and nurs...

Multiple-attribute decision making methods for plant layout design problem

Abstract: The layout design problem is a strategic issue and has a significant impact on the efficiency of a manufacturing system. Much of the existing layout design literature that uses a surrogate function for flow distance or for simplified objectives may be entrapped into local optimum; and subsequently lead to a poor layout design due to the multiple-attribute decision making (MADM) nature of a layout design decision. The present study explores the use of MADM approaches in solving a layout design problem. The proposed methodology is illustrated through a practical application from an IC packaging company. Two methods are proposed in solving the case study problem: Technique for order preference by similarity to ideal solution (TOPSIS) and fuzzy TOPSIS. Empirical results showed that the proposed methods are viable approaches in solving a layout design problem. TOPSIS is a viable approach for the case study problem and is suitable for precise value performance ratings. When the performance ratings are vague and imprecise, the fuzzy TOPSIS is a preferred solution method.

Chemical bath deposition of CdS quantum dots onto mesoscopic TiO2 films for application in quantum-dot-sensitized solar cells

Abstract: Alcohol, instead of water, was used as a solvent in a chemical bath deposition process for the in situ synthesis of CdS quantum dots onto mesoporous TiO2 films. Due to low surface tension, the alcohol solutions have high wettability and superior penetration ability on the mesoscopic TiO2 film, leading to a well-covered CdS on the surface of mesopores. The CdS-sensitized TiO2 electrode prepared using the alcohol system not only has a higher incorporated amount of CdS but also greatly inhibits the recombination of injected electrons. The efficiency of a CdS quantum-dots-sensitized solar cell prepared using the present method is as high as 1.84% under the illumination of one sun (AM1.5, 100mW∕cm2).

Simvastatin is associated with a reduced incidence of dementia and Parkinson's disease

Abstract: Statins are a class of medications that reduce cholesterol by inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A reductase. Whether statins can benefit patients with dementia remains unclear because of conflicting results. We hypothesized that some of the confusion in the literature might arise from differences in efficacy of different statins. We used a large database to compare the action of several different statins to investigate whether some statins might be differentially associated with a reduction in the incidence of dementia and Parkinson's disease. We analyzed data from the decision support system of the US Veterans Affairs database, which contains diagnostic, medication and demographic information on 4.5 million subjects. The association of lovastatin, simvastatin and atorvastatin with dementia was examined with Cox proportional hazard models for subjects taking statins compared with subjects taking cardiovascular medications other than statins, after adjusting for covariates associated with dementia or Parkinson's disease. We observed that simvastatin is associated with a significant reduction in the incidence of dementia in subjects ≥65 years, using any of three models. The first model incorporated adjustment for age, the second model included adjusted for three known risk factors for dementia, hypertension, cardiovascular disease or diabetes, and the third model incorporated adjustment for the Charlson index, which is an index that provides a broad assessment of chronic disease. Data were obtained for over 700000 subjects taking simvastatin and over 50000 subjects taking atorvastatin who were aged >64 years. Using model 3, the hazard ratio for incident dementia for simvastatin and atorvastatin are 0.46 (CI 0.44–0.48, p < 0.0001) and 0.91 (CI 0.80–1.02, p = 0.11), respectively. Lovastatin was not associated with a reduction in the incidence of dementia. Simvastatin also exhibited a reduced hazard ratio for newly acquired Parkinson's disease (HR 0.51, CI 0.4–0.55, p < 0.0001). Simvastatin is associated with a strong reduction in the incidence of dementia and Parkinson's disease, whereas atorvastatin is associated with a modest reduction in incident dementia and Parkinson's disease, which shows only a trend towards significance.

A study on relationship among leadership, organizational culture, the operation of learning organization and employees job satisfaction

Abstract: Purpose – The main purpose of this paper is to investigate the relationship among leadership, organizational culture, the operation of learning organization and employees' job satisfaction.Design/methodology/approach – A quantitative research design was employed. A total of 1,000 questionnaires were mailed out and received 134 valid replies.Findings – The research results indicate that the various operation extents of learning organization have significant difference under the dimensions of leadership, organizational culture and the operation of learning organization. Both leadership and organizational culture can positively and significantly affect the operation of learning organization. In addition, the operation of learning organizations has a significantly positive effect on employees' job satisfaction.Research limitations/implications – Although this research is adopted with questionnaire investigation and concise questions to the best of one's ability it is still not known whether the respondents ca...

Hydrothermal Synthesis of SnO2 Nanoparticles and Their Gas-Sensing of Alcohol

Abstract: A hydrothermal method was used to synthesize nanocrystalline SnO2 particles with an average particle size of 3.0 ± 0.5 nm. Thermally treated SnO2 with an average diameter of 3.3 ± 0.6 nm was obtain...

An empirical investigation of students' behavioural intentions to use the online learning course websites

Abstract: With the development of the Internet in the era of knowledge-driven economy, e-learning is experiencing rapid growth. The online learning course websites are drawing more attention as well. This research combines the innovation diffusion theory and the technology acceptance model, and adds two research variables, perceived system quality and computer self-efficacy to propose a new hybrid technology acceptance model to study students' behavioural intentions to use the online learning course websites. This research finds that compatibility, perceived usefulness, perceived ease of use, perceived system quality and computer self-efficacy were critical factors for students' behavioural intentions to use the online learning course websites. By explaining students' behavioural intentions from a user's perspective, the findings of this research help to develop more user-friendly websites and also provide insight into the best way to promote new e-learning tools for students.

Methotrexate Conjugated to Gold Nanoparticles Inhibits Tumor Growth in a Syngeneic Lung Tumor Model

Abstract: Methotrexate (MTX), a stoichiometric inhibitor of dihydrofolate reductase, is a chemotherapeutic agent for treating a variety of neoplasms Impairment of drug import into cells and increase in drug export from cells may render cells resistant to MTX MTX, when locally administered in a soluble form, is rapidly absorbed through capillaries into the circulatory system, which may also account for therapeutic failure in patients To retain MTX within tumor cells for longer duration and alter its pharmacokinetic behavior, we proposed a new formulation of MTX bound to the gold nanoparticle (AuNP) that serves as drug carriers In this study, we developed the MTX-AuNP conjugate and examined its cytotoxic effect in vitro and antitumor effect in vivo Spectroscopic examinations revealed that MTX can be directly bound onto AuNP via the carboxyl group (-COOH) to form the MTX-AuNP complex and kinetically released from the nanoparticles The accumulation of MTX is faster and higher in tumor cells treated with MTX-AuNP than that treated with free MTX Notably, MTX-AuNP shows higher cytotoxic effects on several tumor cell lines compared with an equal dose of free MTX This can be attributed to the "concentrated effect" of MTX-AuNP Administration of MTX-AuNP suppresses tumor growth in a mouse ascites model of Lewis lung carcinoma (LL2), whereas an equal dose of free MTX had no antitumor effect In conclusion, these results suggest that by combining nanomaterials with anticancer drugs MTX-AuNP may be more effective than free MTX for cancer treatment

Nurses relate the contributing factors involved in medication errors

Abstract: Aims and objectives. Understanding the processes by which nurses administer medication is critical to the minimization of medication errors. This study investigates nurses’ views on the factors contributing to medication errors in the hope of facilitating improvements to medication administration processes. Design and methods. A focus group of nine Registered Nurses discussed medication errors with which they were familiar as a result of both their own experiences and of literature review. The group, along with other researchers, then developed a semi-structured questionnaire consisting of three parts: narrative description of the error, the nurse's background and contributing factors. After the contributing factors had been elicited and verified with eight categories and 34 conditions, additional Registered Nurses were invited to participate by recalling one of the most significant medication errors that they had experienced and identifying contributing factors from those listed on the questionnaire. Identities of the hospital, patient and participants involved in the study remain confidential. Results. Of the 72 female nurses who responded, 55 (76·4%) believed more than one factor contributed to medication errors. ‘Personal neglect’ (86·1%), ‘heavy workload’ (37·5%) and ‘new staff’ (37·5%) were the three main factors in the eight categories. ‘Need to solve other problems while administering drugs,’‘advanced drug preparation without rechecking,’ and ‘new graduate’ were the top three of the 34 conditions. Medical wards (36·1%) and intensive care units (33·3%) were the two most error-prone places. The errors common to the two were ‘wrong dose’ (36·1%) and ‘wrong drug’ (26·4%). Antibiotics (38·9%) were the most commonly misadministered drugs. Conclusions. Although the majority of respondents considered nurse's personal neglect as the leading factor in medication errors, analysis indicated that additional factors involving the health care system, patients’ conditions and doctors’ prescriptions all contributed to administration errors. Relevance to clinical practice. Identification of the main factors and conditions contributing to medication errors allows clinical nurses and administration systems to eliminate situations that promote errors and to incorporate changes that minimize them, creating a safer patient environment.

Examining the integrated influence of fairness and quality on learners’ satisfaction and Web‐based learning continuance intention

Abstract: . As with any other information system (IS), the success of Web-based learning depends largely on user satisfaction and other factors that eventually increase users’ intentions to continue using the service (continuance intention). This research integrates the IS success model and fairness theory to construct a model for investigating the motivations behind learners’ intentions to continue using Web-based learning. Our model theorizes that the three dimensions of quality (i.e. information, system and service) and the three dimensions of fairness (i.e. distributive, procedural and interactional) affect learners’ satisfaction. We also argue that satisfaction and the three dimensions of fairness will influence learners’ intention to continue using Web-based learning. The hypothesized model is validated empirically using data collected from 289 learners of a Web-based learning service. The results show that information quality, system quality, system use, distributive fairness and interactional fairness exhibit significant positive effects on satisfaction. Also, procedural fairness and satisfaction play significant roles in shaping learners’ intention to continue using Web-based learning.

Laterally grown ZnO nanowire ethanol gas sensors

Abstract: We report the growth of ZnO nanowires on ZnO:Ga/glass templates and the fabrication of laterally grown ZnO nanowire ethanol sensors. It was found that growth direction of the nanowires depends strongly on growth parameters. It was also found that resistivity of the fabricated sensor decreased upon ethanol gas injection. By introducing 1500 ppm ethanol gas, it was found that the device response were around 20%, 35%, 58% and 61% when the gas sensor was operated at 180 °C, 230 °C, 260 °C and 300 °C, respectively. It was also found that the device response at 300 °C were around 18%, 26%, 43%, 55% and 61% when the concentration of injected ethanol gas was 50 ppm, 100 ppm, 500 ppm, 1000 ppm and 1500 ppm, respectively.

Virulence characteristics of Klebsiella and clinical manifestations of K. pneumoniae bloodstream infections.

Abstract: We studied 455 consecutive episodes of Klebsiella pneumoniae bacteremia occurring in 7 countries. Community-acquired pneumonia and an invasive syndrome of liver abscess, meningitis, or endophthalmitis occurred only in Taiwan and South Africa. Infections by K1 and K2 capsular serotype, the mucoid phenotype, and aerobactin production were important determinants of virulence. The mucoid phenotype was seen in 94% of isolates in patients with community-acquired pneumonia and in 100% of isolates that caused the invasive syndrome in Taiwan and South Africa, compared with only 2% of isolates elsewhere. Mortality of mice injected with mucoid strains (69%) was strikingly higher than that occurring in mice injected with nonmucoid strains (3%, p<0.001). Differences in clinical features of bacteremic infection with K. pneumoniae are due to the virulence factors expressed by the organism.

Electrokinetic mixing in microfluidic systems

Abstract: The applications of electrokinetics in the development of microfluidic devices have been widely attractive in the past decade. Electrokinetic devices generally require no external mechanical moving parts and can be made portable by replacing the power supply by small battery. Therefore, electrokinetic-based microfluidic systems can serve as a viable tool in creating a lab-on-a-chip (LOC) or micro-total analysis system (μTAS) for use in biological and chemical assays. Mixing of analytes and reagents is a critical step in realizing lab-on-a-chip. This step is difficult due to the low Reynolds numbers flows in microscale devices. Hence, various schemes to enhance micro-mixing have been proposed in the past years. This review reports recent developments in the micro-mixing schemes based on DC and AC electrokinetics, including electrowetting-on-dielectric (EWOD), dielectrophoresis (DEP), and electroosmosis (EO). These electrokinetic-based mixing approaches are generally categorized as either active or passive in nature. Active mixers either use time-dependent (AC or DC field switching) or time-independent (DC field) external electric fields to achieve mixing, while passive mixers achieve mixing in DC fields simply by virtue of their geometric topology and surface properties, or electrokinetic instability flows. Typically, chaotic mixing can be achieved in some ways and is helpful to mixing under large Peclet number regimes. The overview given in this article provides a potential user or researcher of electrokinetic-based technology to select the most favorable mixing scheme for applications in the field of micro-total analysis systems.

Epidemiologic features of hand-foot-mouth disease and herpangina caused by enterovirus 71 in Taiwan, 1998-2005.

Abstract: OBJECTIVE. In 1998, an epidemic of hand-foot-mouth disease/herpangina was caused by human enterovirus 71 infection in Taiwan. The underlying factors of widespread emergence of viral infection are unclear. The purpose of this study was to assess the epidemiology of hand-foot-mouth disease/herpangina in Taiwan between March 1998 and December 2005. METHODS. We analyzed data reported to surveillance systems at the Taiwan Center for Disease Control. Viral isolation was performed by 11 reference virus laboratories at medical centers as well as the Taiwan Center for Disease Control. RESULTS. During the 8-year study period, the reported incidence of mild cases of hand-foot-mouth disease/herpangina varied from 0.8 to 19.9 cases per sentinel physician per week, peaking in 1998. Seasonal variations in incidence were observed, with an incidence peak observed during the summer season. Annual incidence changed significantly from 1998 to 2005. Both age-specific incidence and fatality of severe hand-foot-mouth disease/herpangina decreased as age increased. Most (93%) cases occurred in children who were aged 4 years and younger. Inpatients had a higher rate of enterovirus 71 infection than outpatients. Among severe cases, the majority (80%) had pulmonary edema/hemorrhage and encephalitis. CONCLUSIONS. Hand-foot-mouth disease/herpangina is a common disease in Taiwan. Enterovirus 71 infection has emerged as an important public problem causing serious clinical illness and, potentially, death in young children. Vaccine development is recommended for prevention of enterovirus 71 infection in the future.

An integrated dielectrophoretic chip for continuous bioparticle filtering, focusing, sorting, trapping, and detecting

Abstract: Multi-target pathogen detection using heterogeneous medical samples require continuous filtering, sorting, and trapping of debris, bioparticles, and immunocolloids within a diagnostic chip. We present an integrated AC dielectrophoretic (DEP) microfluidic platform based on planar electrodes that form three-dimensional (3D) DEP gates. This platform can continuously perform these tasks with a throughput of 3 muLmin. Mixtures of latex particles, Escherichia coli Nissle, Lactobacillus, and Candida albicans are sorted and concentrated by these 3D DEP gates. Surface enhanced Raman scattering is used as an on-chip detection method on the concentrated bacteria. A processing rate of 500 bacteria was estimated when 100 mul of a heterogeneous colony of 10(7) colony forming units ml was processed in a single pass within 30 min.

Functionalizing Carbon Nanotubes by Plasma Modification for the Preparation of Covalent-Integrated Epoxy Composites

Abstract: A novel method for preparing a fully integrated nanotube composite material through the use of functionalized multi-walled carbon nanotubes (MWNTs) is presented in this study. The functionalization of MWNTs was performed via plasma treatment; subsequently, maleic anhydride (MA) was grafted onto the MWNTs (CNTs-MA). Nanotube-reinforced epoxy polymer composites were prepared by first mixing the CNTs-MA and a diamine curing agent, followed by a further reaction with the epoxy matrix. In this hybrid nanocomposite system, the CNTs-MA were covalently integrated into the epoxy matrix and became part of the cross-linked structure rather than just a separate component. Fourier transform infrared (FT-IR) and high resolution X-ray photoelectron (XPS) spectroscopes were used to characterize the functional groups on the surface of the MWNTs after the plasma modification. In addition, observations of scanning electronic microscopy (SEM) and transmission electron microscopy (TEM) images showed that the functionalized na...

Simplified Model for Wall Deflection and Ground-Surface Settlement Caused by Braced Excavation in Clays

Abstract: Accurate prediction of ground-surface settlement adjacent to an excavation is often difficult to achieve without using accurate representation of small-strain nonlinearity in a soil model within finite-element analyses. In this paper a simplified semiempirical model is proposed for predicting maximum wall deflection, maximum surface settlement, and surface-settlement profile due to excavations in soft to medium clays. A large number of artificial data are generated through finite-element analyses using a well-calibrated, small-strain soil model. These data, consisting of wall displacements and ground-surface settlements in simulated excavations in soft to medium clays, provide the basis for developing the proposed semiempirical model. The proposed model is verified using case histories not used in the development of the model. The study shows that the developed model can accurately predict maximum wall deflection and ground-surface settlement caused by braced excavations in soft to medium clays.