Showing papers by "National Cheng Kung University published in 2010"

Human papillomavirus genotype attribution in invasive cervical cancer: a retrospective cross-sectional worldwide study

Abstract: Summary Background Knowledge about the distribution of human papillomavirus (HPV) genotypes in invasive cervical cancer is crucial to guide the introduction of prophylactic vaccines. We aimed to provide novel and comprehensive data about the worldwide genotype distribution in patients with invasive cervical cancer. Methods Paraffin-embedded samples of histologically confirmed cases of invasive cervical cancer were collected from 38 countries in Europe, North America, central South America, Africa, Asia, and Oceania. Inclusion criteria were a pathological confirmation of a primary invasive cervical cancer of epithelial origin in the tissue sample selected for analysis of HPV DNA, and information about the year of diagnosis. HPV detection was done by use of PCR with SPF-10 broad-spectrum primers followed by DNA enzyme immunoassay and genotyping with a reverse hybridisation line probe assay. Sequence analysis was done to characterise HPV-positive samples with unknown HPV types. Data analyses included algorithms of multiple infections to estimate type-specific relative contributions. Findings 22 661 paraffin-embedded samples were obtained from 14 249 women. 10 575 cases of invasive cervical cancer were included in the study, and 8977 (85%) of these were positive for HPV DNA. The most common HPV types were 16, 18, 31, 33, 35, 45, 52, and 58 with a combined worldwide relative contribution of 8196 of 8977 (91%, 95% CI 90–92). HPV types 16 and 18 were detected in 6357 of 8977 of cases (71%, 70–72) of invasive cervical cancer. HPV types 16, 18, and 45 were detected in 443 of 470 cases (94%, 92–96) of cervical adenocarcinomas. Unknown HPV types that were identified with sequence analysis were 26, 30, 61, 67, 69, 82, and 91 in 103 (1%) of 8977 cases of invasive cervical cancer. Women with invasive cervical cancers related to HPV types 16, 18, or 45 presented at a younger mean age than did those with other HPV types (50·0 years [49·6–50·4], 48·2 years [47·3–49·2], 46·8 years [46·6–48·1], and 55·5 years [54·9–56·1], respectively). Interpretation To our knowledge, this study is the largest assessment of HPV genotypes to date. HPV types 16, 18, 31, 33, 35, 45, 52, and 58 should be given priority when the cross-protective effects of current vaccines are assessed, and for formulation of recommendations for the use of second-generation polyvalent HPV vaccines. Our results also suggest that type-specific high-risk HPV-DNA-based screening tests and protocols should focus on HPV types 16, 18, and 45. Funding Spanish grants from Instituto de Salud Carlos III, Agencia de Gestio d'Ajuts Universitaris i de Recerca, Marato de TV3 Foundation, and unrestricted grants from GlaxoSmithKline Biologicals, Sanofi Pasteur MSD, and Merck.

A 10-bit 50-MS/s SAR ADC With a Monotonic Capacitor Switching Procedure

Abstract: This paper presents a low-power 10-bit 50-MS/s successive approximation register (SAR) analog-to-digital converter (ADC) that uses a monotonic capacitor switching procedure. Compared to converters that use the conventional procedure, the average switching energy and total capacitance are reduced by about 81% and 50%, respectively. In the switching procedure, the input common-mode voltage gradually converges to ground. An improved comparator diminishes the signal-dependent offset caused by the input common-mode voltage variation. The prototype was fabricated using 0.13-?m 1P8M CMOS technology. At a 1.2-V supply and 50 MS/s, the ADC achieves an SNDR of 57.0 dB and consumes 0.826 mW, resulting in a figure of merit (FOM) of 29 fJ/conversion-step. The ADC core occupies an active area of only 195 × 265 ?m2.

Graphite Oxide as a Photocatalyst for Hydrogen Production from Water

Abstract: A graphite oxide (GO) semiconductor photocatalyst with an apparent bandgap of 2.4–4.3 eV is synthesized by a modified Hummers' procedure. The as-synthesized GO photocatalyst has an interlayer spacing of 0.42 nm because of its moderate oxidation level. Under irradiation with UV or visible light, this GO photocatalyst steadily catalyzes H2 generation from a 20 vol % aqueous methanol solution and pure water. As the GO sheets extensively disperse in water, a cocatalyst is not required for H2 generation over the GO photocatalyst. During photocatalytic reaction, the GO loses some oxygen functional groups, leading to bandgap reduction and increased conductivity. This structural variation does not affect the stable H2 generation over the GO. The encouraging results presented in this study demonstrate the potential of graphitic materials as a medium for water splitting under solar illumination.

CdS/CdSe Co-Sensitized TiO2 Photoelectrode for Efficient Hydrogen Generation in a Photoelectrochemical Cell†

Abstract: An efficient photoelectrode is prepared by sequentially assembled CdS and CdSe quantum dots (QDs) onto a nanocrystalline TiO2 film. The CdS/CdSe co-sensitized photoelectrode was found to have a complementary effect in the light absorption. Furthermore, the cascade structure, TiO2/CdS/CdSe, exhibits a significant enhancement in the current−voltage response, both in dark conditions and under light illumination. On the contrary, the performance of the reverse structure, TiO2/CdSe/CdS, is much less than the electrode using a single sensitizer. The open circuit potentials measured in the dark for these electrodes indicates that a Fermi level alignment occurs between CdS and CdSe after their contact, causing downward and upward shifts of the band edges, respectively, for CdS and CdSe. A stepwise band edge structure is, therefore, constructed in the TiO2/CdS/CdSe electrode, which is responsible for the performance enhancement of this photoelectrode. The saturated photocurrent achieved by the TiO2/CdS/CdSe electr...

UP-Growth: an efficient algorithm for high utility itemset mining

Abstract: Mining high utility itemsets from a transactional database refers to the discovery of itemsets with high utility like profits. Although a number of relevant approaches have been proposed in recent years, they incur the problem of producing a large number of candidate itemsets for high utility itemsets. Such a large number of candidate itemsets degrades the mining performance in terms of execution time and space requirement. The situation may become worse when the database contains lots of long transactions or long high utility itemsets. In this paper, we propose an efficient algorithm, namely UP-Growth (Utility Pattern Growth), for mining high utility itemsets with a set of techniques for pruning candidate itemsets. The information of high utility itemsets is maintained in a special data structure named UP-Tree (Utility Pattern Tree) such that the candidate itemsets can be generated efficiently with only two scans of the database. The performance of UP-Growth was evaluated in comparison with the state-of-the-art algorithms on different types of datasets. The experimental results show that UP-Growth not only reduces the number of candidates effectively but also outperforms other algorithms substantially in terms of execution time, especially when the database contains lots of long transactions.

Microfluidic cell culture systems for drug research.

Abstract: In pharmaceutical research, an adequate cell-based assay scheme to efficiently screen and to validate potential drug candidates in the initial stage of drug discovery is crucial. In order to better predict the clinical response to drug compounds, a cell culture model that is faithful to in vivo behavior is required. With the recent advances in microfluidic technology, the utilization of a microfluidic-based cell culture has several advantages, making it a promising alternative to the conventional cell culture methods. This review starts with a comprehensive discussion on the general process for drug discovery and development, the role of cell culture in drug research, and the characteristics of the cell culture formats commonly used in current microfluidic-based, cell-culture practices. Due to the significant differences in several physical phenomena between microscale and macroscale devices, microfluidic technology provides unique functionality, which is not previously possible by using traditional techniques. In a subsequent section, the niches for using microfluidic-based cell culture systems for drug research are discussed. Moreover, some critical issues such as cell immobilization, medium pumping or gradient generation in microfluidic-based, cell-culture systems are also reviewed. Finally, some practical applications of microfluidic-based, cell-culture systems in drug research particularly those pertaining to drug toxicity testing and those with a high-throughput capability are highlighted.

The application of Fuzzy Delphi Method and Fuzzy AHP in lubricant regenerative technology selection

Abstract: Due to the funding scale and complexity of lubricant regenerative technology, the selection of recycling technology and policy for waste lubricant oil can be viewed as a multiple-attribute decision process that is normally made by a review committee with experts from academia, industry, and the government. This study aims to provide a systematic approach towards the technology selection, in which two phase procedures are proposed. The first stage utilizes Fuzzy Delphi Method to obtain the critical factors of the regenerative technologies by interviewing the foregoing experts. In the second stage, Fuzzy Analytic Hierarchy Process is applied to find the importance degree of each criterion as the measurable indices of the regenerative technologies. This study considers eight kinds of regenerative technologies which have already been widely used, and establishes a ranking model that provides decision makers to assessing the prior order of regenerative technologies. The empirical study indicates that the ''Proper scale'' is the most important evaluation criterion considered in overall experts. The demonstration of how the prior order of regenerative technologies changes under various domains of experts is addressed as well.

Enhanced Thermal Conductivity of Polyimide Films via a Hybrid of Micro-and Nano-Sized Boron Nitride

Abstract: A new thermally conductive polyimide composite film has been developed. It is based on a dispersion of different particle sizes of boron nitride (BN) in a polyimide (PI) precursor, polyamic acid (P...

Novel High Step-Up DC–DC Converter for Fuel Cell Energy Conversion System

Abstract: A novel high step-up dc-dc converter for fuel cell energy conversion is presented in this paper. The proposed converter utilizes a multiwinding coupled inductor and a voltage doubler to achieve high step-up voltage gain. The voltage on the active switch is clamped, and the energy stored in the leakage inductor is recycled. Therefore, the voltage stress on the active switch is reduced, and the conversion efficiency is improved. Finally, a 750-W laboratory prototype converter supplied by a proton exchange membrane fuel cell power source and an output voltage of 400 V is implemented. The experimental results verify the performances, including high voltage gain, high conversion efficiency, and the effective suppression of the voltage stress on power devices. The proposed high step-up converter can feasibly be used for low-input-voltage fuel cell power conversion applications.

Experimental demonstration of a heralded entanglement source

Abstract: The heralded generation of entangled states is a long-standing goal in quantum information processing, because it is indispensable for a number of quantum protocols1,2. Polarization entangled photon pairs are usually generated through spontaneous parametric down-conversion3, but the emission is probabilistic. Their applications are generally accompanied by post-selection and destructive photon detection. Here, we report a source of entanglement generated in an event-ready manner by conditioned detection of auxiliary photons4. This scheme benefits from the stable and robust properties of spontaneous parametric down-conversion and requires only modest experimental efforts. It is flexible and allows the preparation efficiency to be significantly improved by using beamsplitters with different transmission ratios. We have achieved a fidelity better than 87% and a state preparation efficiency of 45% for the source. This could offer promise in essential photonics-based quantum information tasks, and particularly in enabling optical quantum computing by reducing dramatically the computational overhead5,6. An efficient source of entangled photons generated in an event-ready manner by conditioned detection of auxiliary photons is reported. A fidelity better than 87% and a state preparation efficiency of 45% are obtained. The scheme could offer promising applications in essential photonics-based quantum information tasks, and represents a particularly important development in the realization of optical quantum computing.

In Vitro and in Vivo Studies of FePt Nanoparticles for Dual Modal CT/MRI Molecular Imaging

Abstract: The water-solvable FePt nanoparticles of 3, 6, and 12 nm in diameter (3 nm-, 6 nm-, and 12 nm-FePt) were synthesized and applied as a dual modality contrast agent for CT/MRI molecular imaging. These nanoparticles present excellent biocompatibility and hemocompatibility in all test concentrations for the imaging contrast. The biodistribution analysis revealed the highest serum concentration and circulation half-life for 12 nm-FePt, followed by 6 nm-FePt then 3 nm-FePt. Thus, the 3 nm-FePt showed higher brain concentrations. Anti-Her2 antibody conjugated FePt nanoparticles demonstrated molecular expression dependent CT/MRI dual imaging contrast effect in MBT2 cell line and its Her2/neu gene knock out counterpart. Selective contrast enhancement of Her2/neu overexpression cancer lesions in both CT and MRI was found in tumor bearing animal after tail vein injection of the nanoparticles. The 12 nm-FePt outperformed 3 nm-FePt in both imaging modalities. These results indicate the potential of FePt nanoparticles to serve as novel multimodal molecular imaging contrast agents in clinical settings.

A systematic review and meta-analysis on the therapeutic equivalence of statins.

Abstract: Summary Background: Statins are the most commonly prescribed agents for hypercholesterolemia because of their efficacy and tolerability. As the number of patients in need of statin therapy continues to increase, information regarding the relative efficacy and safety of statins is required for decision-making. Objective: This study will use systematic review to compare the efficacy and safety profiles of different statins at different doses and determine the therapeutically equivalent doses of statins to achieve a specific level of low-density lipoprotein cholesterol (LDL-C) lowering effect. Methods: Publications of head-to-head randomized controlled trials (RCTs) of statins were retrieved from the Oregon state database (1966–2004), MEDLINE (2005-April of 2006), EMBASE (2005-April of 2006), and the Cochrane Controlled Trials Registry (up to the first quarter of 2006). The publications were evaluated with predetermined criteria by a reviewer before they were included in the review. The mean change in cholesterol level of each statin was calculated and weighted by number of subjects involved in each RCT. Where possible, meta-analysis was performed to generate pooled estimates of the cholesterol lowering effect of statins and the difference between statins. Results: Seventy-five studies reporting RCTs of head-to-head comparisons on statins were included. Most studies had similar baseline characteristics, except the rosuvastatin related studies. A daily dose of atorvastatin 10 mg, fluvastatin 80 mg, lovastatin 40–80 mg, and simvastatin 20 mg could decrease LDL-C by 30–40%, and fluvastatin 40 mg, lovastatin 10–20 mg, pravastatin 20–40 mg, and simvastatin 10 mg could decrease LDL-C by 20–30%. The only two statins that could reduce LDL-C more than 40% were rosuvastatin and atorvastatin at a daily dose of 20 mg or higher. Meta-analysis indicated a statistically significant but clinically minor difference (<7%) between statins in cholesterol lowering effect. Comparisons of coronary heart disease prevention and safety could not be made because of insufficient data. Conclusions: At comparable doses, statins are therapeutically equivalent in reducing LDL-C.

Gold Nanorods in Photodynamic Therapy, as Hyperthermia Agents, and in Near-Infrared Optical Imaging

Abstract: Decreasing the size of a material to the nanometer scale makes it sensitive to a further decrease in size or a change in shape. Among the nanomaterials that are currently being developed, gold nanoparticles are extensively exploited in organisms because of their good stability and biocompatibility. However, in biomedical applications that require a considerably deeper penetration of near-infrared (NIR) light, in which both blood and soft tissues are highly penetrable, a different type of gold nanostructure is required. Surface plasmon resonance (SPR) is a phenomenon in which free electrons in the nanostructures collectively oscillate and scatter or absorb the incident electromagnetic wave. Previous studies have demonstrated various methods of shifting the SPR of gold nanomaterials to the NIR region and shown their potential in biological applications. In the NIR region, tissue transmission is optimal owing to low scattering and energy absorption, thus providing maximum irradiation penetration through tissue and minimizing the autofluorescence of the non-target tissue. There are many applications for NIR-absorbing gold nanostructures in biology, and in particular gold nanorods. For example, gold nanorods can be applied in plasmon resonance light scattering, Rayleigh elastic scattering, surface-enhanced Raman inelastic scattering, optical coherent tomography scattering, twophoton luminescent non-linear imaging, and photothermal therapy. Gold nanorods have also received significant attention for their emerging potential in photothermal therapy. However, little attention has been paid to the use of nanorods combined with photosensitizers in photodynamic therapy (PDT), which is the destruction of cancer cells by the highly reactive singlet oxygen of the reactive oxygen species (ROS) produced by a photosensitizing compound and light of an appropriate wavelength. Gold nanorods couple a hydrophilic and anionic photosensitizer, indocyanine green (ICG) (Supporting Information, Figure S1), with light from an NIR laser emitting in the NIR region on the surface of the nanorods to produce PDT. Furthermore, the excitation and emission maxima of ICG are similar to NIR wavelengths, thus enabling ICG-conjugated gold nanorods to be utilized as an effective contrast agent in biomedical imaging. Practical applications in the early detection and destruction of cancer cells using nanomaterials have emerged in recent years, and the development of multifunctional nanomaterials is currently being pursued. Herein, we propose a medical diagnosis method that uses a lethal photochemical destruction reaction and shows that multifunctional ICGconjugated gold nanorods can simultaneously serve as photodynamic and photothermal therapeutic agents to destroy cancer cells. Furthermore, combined PDT and hyperthermia can more efficiently extinguish cancer cells than PDT or hyperthermia treatment alone, and the system can also serve as an effective bioimaging probe in the NIR region. Gold nanorods with a cetyltrimethylammonium bromide (CTAB) surfactant coating were synthesized using the seedless growth method. To conjugate ICG on the surface, CTAB was coated on the nanorods with poly(styrene-altmaleic acid) (PSMA) and ICG in sequence by an electrostatic interaction. A TEM image (Figure 1) depicts gold nanorods with an aspect ratio of approximately 3.8 (length: 35 nm, width: 9.3 nm). Owing to CTAB, the surface charge of the nanorods revealed a zeta potential of approximately 39.2 mV. PSMA polymer was then first hydrolyzed by NaOH to expose the carboxyl group and then adsorbed on the nanorods by electrostatic interactions (Supporting Information, Figure S2). Figure 1 b shows Au-PSMA nanorods with negatively charged PSMA; the Au-PSMA nanorods have a surface charge of approximately 10.7 mV. By the p–p stacking

A Study of Loosely Coupled Coils for Wireless Power Transfer

Abstract: Nonradiative wireless power transfer using magnetically coupled coils is studied in order to transfer a predetermined amount of power at the maximum efficiency. Accordingly, a conceptual wireless power transfer system and a tuning method are presented. Such a study is essential for effectively exploiting the inherent ability of a given pair of coupled coils. With the equations for inductance and resistance calculations, the system performance is evaluated and verified with well-known experimental results and circuit simulations.

A 10b 100MS/s 1.13mW SAR ADC with binary-scaled error compensation

Abstract: In recent years, due to the improvements in CMOS technologies, medium resolution (8 to 10b) SAR ADCs have been able to achieve sampling rates of several tens of MS/s with excellent power efficiency and small area [1]–[4]. When the sampling rate increases, the SAR ADCs suffer from settling issues. In a typical 10b 100MS/s ADC, when the sampling settling time, comparator active time and SAR logic delay are subtracted from each period, the DAC settling time has to be less than 0.4ns in each bit cycle. Such a short time interval is not sufficient for the capacitive DAC to stabilize because the increasing interconnect line impedance in advanced processes slows down the charge transfer, especially in the longest routing path of the DAC capacitor network. Furthermore, the reference voltage sinks noise and line coupling also affects the settling. A non-binary SAR can tolerate DAC settling error at the cost of increased design complexity and hardware overhead [1]. This paper reports a 10b SAR ADC that uses binary-scaled DAC networks for settling error compensation. The ADC achieves 100MS/s while consuming only 1.13mW.

Evolution, genomic analysis, and reconstruction of isobutanol tolerance in Escherichia coli

Abstract: Escherichia coli has been engineered to produce isobutanol, with titers reaching greater than the toxicity level. However, the specific effects of isobutanol on the cell have never been fully understood. Here, we aim to identify genotype–phenotype relationships in isobutanol response. An isobutanol-tolerant mutant was isolated with serial transfers. Using whole-genome sequencing followed by gene repair and knockout, we identified five mutations (acrA, gatY, tnaA, yhbJ, and marCRAB) that were primarily responsible for the increased isobutanol tolerance. We successfully reconstructed the tolerance phenotype by combining deletions of these five loci, and identified glucosamine-6-phosphate as an important metabolite for isobutanol tolerance, which presumably enhanced membrane synthesis. The isobutanol-tolerant mutants also show increased tolerance to n-butanol and 2-methyl-1-butanol, but showed no improvement in ethanol tolerance and higher sensitivity to hexane and chloramphenicol than the parental strain. These results suggest that C4, C5 alcohol stress impacts the cell differently compared with the general solvent or antibiotic stresses. Interestingly, improved isobutanol tolerance did not increase the final titer of isobutanol production.

Efficiency measurement for network systems: IT impact on firm performance

Abstract: A recent development in DEA (data envelopment analysis) examines the internal structure of a system so that more information regarding sources that cause inefficiency can be obtained. This paper discusses a network DEA model which distributes the system inefficiency to its component processes. The model is applied to assess the impact of information technology (IT) on firm performance in a banking industry. The results show that the impact of IT on firm performance operates indirectly through fund collection. The impact increases when the IT budget is shared with the profit generation process.

A 10-bit 50-MS/s SAR ADC With a Monotonic Capacitor Switching Procedure

Abstract: This paper presents a low-power 10-bit 50-MS/s successive approximation register (SAR) analog-to-digital converter (ADC) that uses a monotonic capacitor switching procedure. Compared to converters that use the conventional procedure, the average switching energy and total capacitance are reduced by about 81% and 50%, respectively. In the switching procedure, the input common-mode voltage gradually converges to ground. An improved comparator diminishes the signal-dependent offset caused by the input common-mode voltage variation. The prototype was fabricated using 0.13-μm 1P8M CMOS technology. At a 1.2-V supply and 50 MS/s, the ADC achieves an SNDR of 57.0 dB and consumes 0.826 mW, resulting in a figure of merit (FOM) of 29 fJ/conversion-step. The ADC core occupies an active area of only 195 × 265 μm 2 .

A Novel MYBS3-Dependent Pathway Confers Cold Tolerance in Rice

Abstract: Rice (Oryza sativa) seedlings are particularly sensitive to chilling in early spring in temperate and subtropical zones and in high-elevation areas. Improvement of chilling tolerance in rice may significantly increase rice production. MYBS3 is a single DNA-binding repeat MYB transcription factor previously shown to mediate sugar signaling in rice. In this study, we observed that MYBS3 also plays a critical role in cold adaptation in rice. Gain- and loss-of-function analyses indicated that MYBS3 was sufficient and necessary for enhancing cold tolerance in rice. Transgenic rice constitutively overexpressing MYBS3 tolerated 4°C for at least 1 week and exhibited no yield penalty in normal field conditions. Transcription profiling of transgenic rice overexpressing or underexpressing MYBS3 led to the identification of many genes in the MYBS3-mediated cold signaling pathway. Several genes activated by MYBS3 as well as inducible by cold have previously been implicated in various abiotic stress responses and/or tolerance in rice and other plant species. Surprisingly, MYBS3 repressed the well-known DREB1/CBF-dependent cold signaling pathway in rice, and the repression appears to act at the transcriptional level. DREB1 responded quickly and transiently while MYBS3 responded slowly to cold stress, which suggests that distinct pathways act sequentially and complementarily for adapting short- and long-term cold stress in rice. Our studies thus reveal a hitherto undiscovered novel pathway that controls cold adaptation in rice.

Get With The Guidelines-Stroke Performance Indicators: Surveillance of Stroke Care in the Taiwan Stroke Registry Get With The Guidelines-Stroke in Taiwan

Abstract: Background—Stroke is a leading cause of death around the world. Improving the quality of stroke care is a global priority, despite the diverse healthcare economies across nations. The American Heart Association/American Stroke Association Get With the Guidelines-Stroke program (GWTG-Stroke) has improved the quality of stroke care in 790 US academic and community hospitals, with broad implications for the rest of the country. The generalizability of GWTG-Stroke across national and economic boundaries remains to be tested. The Taiwan Stroke Registry, with 30 599 stroke admissions between 2006 and 2008, was used to assess the applicability of GWTG-Stroke in Taiwan, which spends ≈1/10 of what the United States does in medical costs per new or recurrent stroke. Methods and Results—Taiwan Stroke Registry, sponsored by the Taiwan Department of Health, engages 39 academic and community hospitals and covers the entire country with 4 steps of quality control to ensure the reliability of entered data. Five GWTG-Stro...

Spectrum Sharing in Cognitive Radio Networks—An Auction-Based Approach

Abstract: Cognitive radio is emerging as a promising technique to improve the utilization of the radio frequency spectrum. In this paper, we consider the problem of spectrum sharing among primary (or ?licensed?) users (PUs) and secondary (or ?unlicensed?) users (SUs). We formulate the problem based on bandwidth auction, in which each SU makes a bid for the amount of spectrum and each PU may assign the spectrum among the SUs by itself according to the information from the SUs without degrading its own performance. We show that the auction is a noncooperative game and that Nash equilibrium (NE) can be its solution. We first consider a single-PU network to investigate the existence and uniqueness of the NE and further discuss the fairness among the SUs under given conditions. Then, we present a dynamic updating algorithm in which each SU achieves NE in a distributed manner. The stability condition of the dynamic behavior for this spectrum-sharing scheme is studied. The discussion is generalized to the case in which there are multiple PUs in the network, where the properties of the NE are shown under appropriate conditions. Simulations were used to evaluate the system performance and verify the effectiveness of the proposed algorithm.