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2017

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Articles 11071 - 11100 of 12521

Full-Text Articles in Physical Sciences and Mathematics

Development Of Metal Oxide Arrester Block Using A Rare Earth Element For Very Fast Transient Overvoltage Applications, Kannadasan Raju, Valsalal Prasad, Jayavel Ramasamy Jan 2017

Development Of Metal Oxide Arrester Block Using A Rare Earth Element For Very Fast Transient Overvoltage Applications, Kannadasan Raju, Valsalal Prasad, Jayavel Ramasamy

Turkish Journal of Electrical Engineering and Computer Sciences

The protection ability of metal oxide arresters against switching, lightning, and steep current surges has been well proven. On the contrary, during the invasion of very fast transients, the existing arrester fails to operate due to delay in its initial response. In order to decrease the delay, it is imperative to improve the electrical properties of the arrester such as nonlinearity and voltage gradient with reduced capacitive effect. In this context, new arrester blocks are developed with the addition of a rare earth element, namely scandium trioxide (Sc$_{2}$O$_{3})$, and then sintered with a microwave sintering process. Owing to the uniform …

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Geospatial Drivers Of The Groundwater Δ18o Isoscape In A Temperate Maritime Climate (Republic Of Ireland), S. Regan, R. Goodhue, O. Naughton, Paul Hynds Jan 2017

Geospatial Drivers Of The Groundwater Δ18o Isoscape In A Temperate Maritime Climate (Republic Of Ireland), S. Regan, R. Goodhue, O. Naughton, Paul Hynds

Articles

In recent years, the concept of “isoscapes” has been used to describe spatiotemporal stable isotope distributions within natural environments including groundwater systems at multiple scales. This study presents an updated groundwater δ18O isoscape for the Republic of Ireland and describes the climatic and geological drivers influencing 18O composition. In all, 142 geographically and geologically representative groundwater installations were sampled and analysed, in addition to 35 samples from six nested boreholes. Geospatially, Irish groundwater exhibits high δ18O values in southern and western coastal regions, becoming progressively depleted inland before reaching lowest measured values along the eastern coast, equating to a national …

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An Iterative Bézier Method For Fitting Beta-Sheet Component Of A Cryo-Em Density Map, Michael Poteat, Jing He Jan 2017

An Iterative Bézier Method For Fitting Beta-Sheet Component Of A Cryo-Em Density Map, Michael Poteat, Jing He

Computer Science Faculty Publications

Cryo-electron microscopy (Cryo-EM) is a powerful technique to produce 3-dimensional density maps for large molecular complexes. Although many atomic structures have been solved from cryo-EM density maps, it is challenging to derive atomic structures when the resolution of density maps is not sufficiently high. Geometrical shape representation of secondary structural components in a medium-resolution density map enhances modeling of atomic structures. We compare two methods in producing surface representation of the β-sheet component of a density map. Given a 3-dimensional volume of β-sheet that is segmented from a density map, the performance of a polynomial fitting was compared with that …

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Longer-Term Impact Of Highand Low Temperature On Mortality: An International Study To Clarify Length Of Mortality Displacement, Ben Armstrong, Michelle Bell, Micheline De Sousa Zanotti Stagliorio Coelho, Yue Liang Leon Guo, Yuming Guo, Patrick J. Goodman, Masahiro Hashizume, Yasushi Honda, Ho Kim, Eric Lavigne, Paola Michelozzi, Paulo Hilario Nascimento Saldiva, Joel Schwartz, Matteo Scortichini, Francesco Sera, Aurelio Tobias, Shilu Tong, Chang Fu Wu, Antonella Zanobetti, Ariana Zeka, Antonio Gasparrini Jan 2017

Longer-Term Impact Of Highand Low Temperature On Mortality: An International Study To Clarify Length Of Mortality Displacement, Ben Armstrong, Michelle Bell, Micheline De Sousa Zanotti Stagliorio Coelho, Yue Liang Leon Guo, Yuming Guo, Patrick J. Goodman, Masahiro Hashizume, Yasushi Honda, Ho Kim, Eric Lavigne, Paola Michelozzi, Paulo Hilario Nascimento Saldiva, Joel Schwartz, Matteo Scortichini, Francesco Sera, Aurelio Tobias, Shilu Tong, Chang Fu Wu, Antonella Zanobetti, Ariana Zeka, Antonio Gasparrini

Articles

In many places, daily mortality has been shown to increase after days with particularly high or low temperatures, but such daily time-series studies cannot identify whether such increases reflect substantial life shortening or short-term displacement of deaths (harvesting).

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Online Hacker Forum Censorship: Would Banning The Bad Guys Attract Good Guys?, Qiu-Hong Wang, Le-Ting Zhang, Meng-Ke Qiao Jan 2017

Online Hacker Forum Censorship: Would Banning The Bad Guys Attract Good Guys?, Qiu-Hong Wang, Le-Ting Zhang, Meng-Ke Qiao

Research Collection School Of Computing and Information Systems

To tackle the ubiquitous cybersecurity threats, a few countries have enacted legislation to criminalize the production, distribution and possession of computer misuse tools. Consequently, online hacker forums, which enable the provision and dissemination of malicious cyber-attack techniques among potential hackers or technology-savvy users, are subject to censorship. This project examines the mixed impacts of online hacker forum censorship on users’ contribution to protection discussion through a natural experiment with large-scale content analysis. We find that while the enforcement indeed reduced the discussion on malicious cyber-attacks, the discussion on cybersecurity protection could increase or decrease in different scenarios. The rationale is …

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Technology Mergers And Acquisitions In The Presence Of An Installed Base: A Strategic Analysis, Qiu-Hong Wang, Kai-Lung Hui Jan 2017

Technology Mergers And Acquisitions In The Presence Of An Installed Base: A Strategic Analysis, Qiu-Hong Wang, Kai-Lung Hui

Research Collection School Of Computing and Information Systems

We study the strategic benefits of M&A when competing IT vendors sell different generations of the same product with different quality. We assume the new product arrives unexpectedly when an installed base of old product exists. We show that the combination of consumers' purchase history and heterogeneity leads to new demand complexity that gives rise to innovative product strategies. We find that shelving the old product is an important motivation for M&A. The acquirer may exercise static or intertemporal price discrimination depending on whether it can exercise upgrade pricing. M&A may speed up or slow down new product consumption, and …

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High Impact Bug Report Identification With Imbalanced Learning Strategies, Xinli Yang, David Lo, Xin Xia, Qiao Huang, Jianling Sun Jan 2017

High Impact Bug Report Identification With Imbalanced Learning Strategies, Xinli Yang, David Lo, Xin Xia, Qiao Huang, Jianling Sun

Research Collection School Of Computing and Information Systems

In practice, some bugs have more impact than others and thus deserve more immediate attention. Due to tight schedule and limited human resources, developers may not have enough time to inspect all bugs. Thus, they often concentrate on bugs that are highly impactful. In the literature, high-impact bugs are used to refer to the bugs which appear at unexpected time or locations and bring more unexpected effects (i.e., surprise bugs), or break pre-existing functionalities and destroy the user experience (i.e., breakage bugs). Unfortunately, identifying high-impact bugs from thousands of bug reports in a bug tracking system is not an easy …

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Sensor-Driven Detection Of Social Isolation In Community-Dwelling Elderly, W K P Neranjana Nadee Rodrigo Goonawardene, Xiaoping Toh, Hwee-Pink Tan Jan 2017

Sensor-Driven Detection Of Social Isolation In Community-Dwelling Elderly, W K P Neranjana Nadee Rodrigo Goonawardene, Xiaoping Toh, Hwee-Pink Tan

Research Collection School Of Computing and Information Systems

Ageing-in-place, the ability to age holistically in the community, is increasingly gaining recognition as a solution to address resource limitations in the elderly care sector. Effective elderly care models require a personalised and all-encompassing approach to caregiving. In this regard, sensor technologies have gained attention as an effective means to monitor the wellbeing of elderly living alone. In this study, we seek to investigate the potential of non-intrusive sensor systems to detect socially isolated community dwelling elderly. Using a mixed method approach, our results showed that sensor-derived features such as going-out behavior, daytime napping and time spent in the living …

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Safestack+: Enhanced Dual Stack To Combat Data-Flow Hijacking, Yan Lin, Xiaoxiao Tang, Debin Gao Jan 2017

Safestack+: Enhanced Dual Stack To Combat Data-Flow Hijacking, Yan Lin, Xiaoxiao Tang, Debin Gao

Research Collection School Of Computing and Information Systems

SafeStack, initially proposed as a key component of Code Pointer Integrity (CPI), separates the program stack into two distinct regions to provide a safe region for sensitive code pointers. SafeStack can prevent buffer overflow attacks that overwrite sensitive code pointers, e.g., return addresses, to hijack control flow of the program, and has been incorporated into the Clang project of LLVM as a C-based language front-end. In this paper, we propose and implement SafeStack+, an enhanced dual stack LLVM plug-in that further protects programs from data-flow hijacking. SafeStack+ locates data flow sensitive variables on the unsafe stack that could potentially affect …

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They All Seem Good, But Which One Fits Me? Reducing Fit Uncertainty For Digital Entertainment Goods, Ai Phuong Hoang Jan 2017

They All Seem Good, But Which One Fits Me? Reducing Fit Uncertainty For Digital Entertainment Goods, Ai Phuong Hoang

Research Collection School Of Computing and Information Systems

Faster Internet connections and advanced streaming technologies have boosted the consumption of digital entertainment content. Nonetheless, many content providers are still struggling to differentiate their services and sell their offerings in the market, due to the large number of options available and customers’ uncertainty about the specific attributes of individual information goods. The providers employ different strategies to communicate information on the quality and fit of their products. In this research, I examine the effectiveness of sampling-based seller strategy on the marketing of digital entertainment goods. Using a large dataset on series drama on-demand, I show that content sampling plays …

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The Habits Of Highly Effective Researchers: An Empirical Study, Subhajit Datta, Partha Basuchowdhuri, Surajit Acharya, Subhashis Majumder Jan 2017

The Habits Of Highly Effective Researchers: An Empirical Study, Subhajit Datta, Partha Basuchowdhuri, Surajit Acharya, Subhashis Majumder

Research Collection School Of Computing and Information Systems

Interest in the habits of influential individuals cuts across domains. As researchers, we are intrigued why few attain significant eminence in their fields, whereas many operate in obscurity. An empirical examination of this question has been made possible by the recent availability of large scale publication data. In this paper, we use information from the AMiner Paper Citation and Author Collaboration Networks to discern factors that relate to the impact of influential researchers across five domains in the computing discipline. We propose and apply a novel algorithm to identify influential vertices in co-authorship networks built from total corpora of 1,00,000+papers …

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Cross-Modal Recipe Retrieval: How To Cook This Dish?, Jingjing Chen, Lei Pang, Chong-Wah Ngo Jan 2017

Cross-Modal Recipe Retrieval: How To Cook This Dish?, Jingjing Chen, Lei Pang, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In social media users like to share food pictures. One intelligent feature, potentially attractive to amateur chefs, is the recommendation of recipe along with food. Having this feature, unfortunately, is still technically challenging. First, the current technology in food recognition can only scale up to few hundreds of categories, which are yet to be practical for recognizing ten of thousands of food categories. Second, even one food category can have variants of recipes that differ in ingredient composition. Finding the best-match recipe requires knowledge of ingredients, which is a fine-grained recognition problem. In this paper, we consider the problem from …

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Fine-Grained Sentiment Analysis Of Social Media With Emotion Sensing, Zhaoxia Wang, Chee Seng Chong, Landy Lan, Yinping Yang, Beng-Seng Ho, Joo Chuan Tong Jan 2017

Fine-Grained Sentiment Analysis Of Social Media With Emotion Sensing, Zhaoxia Wang, Chee Seng Chong, Landy Lan, Yinping Yang, Beng-Seng Ho, Joo Chuan Tong

Research Collection School Of Computing and Information Systems

Social media is arguably the richest source of human generated text input. Opinions, feedbacks and critiques provided by internet users reflect attitudes and sentiments towards certain topics, products, or services. The sheer volume of such information makes it effectively impossible for any group of persons to read through. Thus, social media sentiment analysis has become an important area of work to make sense of the social media talk. However, most existing sentiment analysis techniques focus only on the aggregate level, classifying sentiments broadly into positive, neutral or negative, and lack the capabilities to perform fine-grained sentiment analysis. This paper describes …

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Spatiotemporal Distribution Of Eutrophication In Lake Tai As Affected By Wind, Wenhui Zhang, Qiujin Xu, Xixi Wang, Xiaozhen Hu, Cheng Wang, Yan Pang, Yanbin Hu, Yang Zhao, Xiao Zhao Jan 2017

Spatiotemporal Distribution Of Eutrophication In Lake Tai As Affected By Wind, Wenhui Zhang, Qiujin Xu, Xixi Wang, Xiaozhen Hu, Cheng Wang, Yan Pang, Yanbin Hu, Yang Zhao, Xiao Zhao

Civil & Environmental Engineering Faculty Publications

One common hypothesis is that wind can affect concentrations of nutrients (i.e., nitrogen and phosphorus) and chlorophyll-a (Chl-a) in shallow lakes. However, the tests of this hypothesis have yet to be conclusive in existing literature. The objective of this study was to use long-term data to examine how wind direction and wind speed affect the spatiotemporal variations of total nitrogen (TN), total phosphorus (TP) and Chl-a in Lake Tai, a typical shallow lake located in east China. The results indicated that the concentrations of nutrients and Chl-a tended to decrease from the northwest to the southeast of Lake Tai, with …

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Heavy Metal Distribution And Groundwater Quality Assessment For A Coastal Area On A Chinese Island, Sha Lou, Shuguang Liu, Chaomeng Dai, An Tao, Bo Tan, Gangfeng Ma, Roman Sergeeyvich Chalov, Sergey Romanovich Chalov Jan 2017

Heavy Metal Distribution And Groundwater Quality Assessment For A Coastal Area On A Chinese Island, Sha Lou, Shuguang Liu, Chaomeng Dai, An Tao, Bo Tan, Gangfeng Ma, Roman Sergeeyvich Chalov, Sergey Romanovich Chalov

Civil & Environmental Engineering Faculty Publications

Chongming Island is located in the lower Yangtze Estuary in China. Due to the Leachate from a refuse landfill and the hydrodynamics of the Yangtze Estuary, the groundwater environment is particularly complicated on Chongming Island. Field observations were carried out around the landfill disposal site. The groundwater table, temperature, pH, salinity, and dissolved oxygen were measured in the field by portable equipment, and 192 water samples were collected at eight groundwater sites and one surface water site. Through laboratory analysis we found the highest measured concentration of Cr to be 54.07 μg/L, and the measured concentration of Zn was in …

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Group Divisible Designs With Two Groups And Three Associate Classes, Ladamas Saiphet Jan 2017

Group Divisible Designs With Two Groups And Three Associate Classes, Ladamas Saiphet

Chulalongkorn University Theses and Dissertations (Chula ETD)

No abstract provided.

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3d Printing Of Graphene/Thermoplastic Elastomer Composites, Warrayut Kanabenja Jan 2017

3d Printing Of Graphene/Thermoplastic Elastomer Composites, Warrayut Kanabenja

Chulalongkorn University Theses and Dissertations (Chula ETD)

Graphene based thermoplastic polyurethane composites filaments was prepared by melt blending process prior to fabricate with 3D printing technique. The effects of different graphene loading (0.05 wt% - 0.20 wt%) in TPU matrix on the properties of composites were studied. Initially, graphite was successfully oxidized to graphite oxide following Hummer’s method and the reduction of graphene oxide to graphene by L-ascorbic acid was also achieved as being confirmed by the FTIR and XRD results. TPU and TPU/graphene nanocomposites were investigated for their thermal, mechanical, physical and electrical properties. Thermal stability of TPU/graphene composites was improved against neat TPU. The first …

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Cuckoo Search And Enhanced Artificial Bee Colony Heuristic Methods For Vehicle Routing Problem With Backhaul And Time Window Constraints, Tanawat Worawattawechai Jan 2017

Cuckoo Search And Enhanced Artificial Bee Colony Heuristic Methods For Vehicle Routing Problem With Backhaul And Time Window Constraints, Tanawat Worawattawechai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The vehicle routing problem with backhauls and time windows (VRPBTW) aims to find a feasible vehicle route that minimizes the total traveling distance while imposing capacity, backhaul, and time-window constraints. In this dissertation, a mathematical model of VRPBTW is introduced to obtain an optimal solution. The heuristics, namely the nearest urgent candidate (NUC), which applies the urgency priority and candidate techniques, and the nearest neighbor with roulette wheel selection (NNRW) which is a combination of a roulette wheel selection method and the improved nearest neighbor heuristic, are also presented to solve this problem. Moreover, two metaheuristic methods are presented to …

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Hydrogen Rich Gas Production From Pyrolysis-Gasification Of Biomass With Combined Catalyst And Sorbent, Teerayut Bunma Jan 2017

Hydrogen Rich Gas Production From Pyrolysis-Gasification Of Biomass With Combined Catalyst And Sorbent, Teerayut Bunma

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, the hydrogen production during biomass steam pyrolysis-gasification with a combined catalysts and sorbent (catalyst/sorbents) was studied in a drop tube two-stages fixed bed reactor. The catalyst/sorbents were prepared by an excess-solution impregnation method. A nickel oxide (NiO)/magnesium oxide (MgO)/calcium oxide(CaO) catalyst/sorbents containing 10 wt. % NiO, 5 wt. % MgO and 5 wt. % CaO on gamma alumina (γ-Al2O3) showed the best activity in sorption enhanced hydrogen production (SEHP) for the pyrolysis-gasification of sugarcane leaves. Besides, the highest H2 concentration and the lowest CO2 concentration were attained using the Mg5Ni10Ca5 catalyst/sorbents. Because Mg5Ni10Ca5 catalyst/sorbents provided the dominant …

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Nanomaterial Sensors For Selective Detection Of Biothiol Compounds, Chiraporn Chaicham Jan 2017

Nanomaterial Sensors For Selective Detection Of Biothiol Compounds, Chiraporn Chaicham

Chulalongkorn University Theses and Dissertations (Chula ETD)

Novel nanomaterial sensors have been designed two different strategies of sensing approach. The first sensing system, the aggregation nanomicelles (TSC and TSD) were synthesized for GSH sensing based on disulfide-cleavaged trigger in the micelle. The result showed a large quenching fluorescent intensity around 587 nm and 528 nm corresponding to TSC and TSD, respectively, upon the addition of GSH in 2.5% DMSO/PBS at pH 6. Additionally, the benefit of TSD is utility for the distance-based fluorescence detection of 3D paper analytical device (3D-µPAD) for the detection of GSH. Apart from GQDs sensors base, we demonstrated the utility and board applicability …

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Application Of Headspace-Gas Chromatography-Mass Spectrometry For Characterization Of Volatile Compounds In Chicken Eggs, Hanan Jehma Jan 2017

Application Of Headspace-Gas Chromatography-Mass Spectrometry For Characterization Of Volatile Compounds In Chicken Eggs, Hanan Jehma

Chulalongkorn University Theses and Dissertations (Chula ETD)

Volatile compounds in chicken eggs under the cold chain system and non-cold chain system were characterized by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with chemometrics. According to a central composite design, the following optimum HS-SPME extraction conditions were obtained: extraction temperature of 65 oC, extraction time of 45 min and the amount of NaCl of 0.4 g. In comparison of their mass spectrum and linear retention index from HS-SPME-GC-MS analysis, major volatile compounds found in egg samples included toluene, hexanal, nonanal and other minor volatile compounds were heptanal, octanal, decanal, benzaldehyde, 1-octen-3-ol and 2-ethyl-1-hexanol, with the types and amounts …

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Selective Esterification Of Glycerol With Oleic Acid Using Tungstophosphoric Acid Supported On Functionalized Mesoporous Silica, Kullatida Ratchadapiban Jan 2017

Selective Esterification Of Glycerol With Oleic Acid Using Tungstophosphoric Acid Supported On Functionalized Mesoporous Silica, Kullatida Ratchadapiban

Chulalongkorn University Theses and Dissertations (Chula ETD)

A series of protonated amine-functionalized SBA-15 materials was successfully prepared. Each sample of mesoporous SBA-15 was first functionalized with each of the three types of amino-organosilanes: APTES (N), AAPTMS (NN), and DETTMS (NNN). Each of the resulting materials was then protonated with Keggin-type tungstophosphoric acid (HPW) at two different concentrations: 20 wt.% (H20) and 40 wt.% (H40). The six types of materials obtained were labelled as S-N1-H20, S-N1-H40, S-NN1-H20, S-NN1-H40, S-NNN1-H20, and S-NNN1-H40. The materials were fully characterized by XRD, N2 adsorption-desorption, FT-IR, SEM/EDX, TEM, and elemental analysis. The characterization results show that the synthesized materials exhibited highly ordered hexagonal …

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Preparation Of Rigid Polyurethane Foams Catalyzed By Metal-Asparagine And Metal-Threonine Complexes, Nuttiya Jintana Jan 2017

Preparation Of Rigid Polyurethane Foams Catalyzed By Metal-Asparagine And Metal-Threonine Complexes, Nuttiya Jintana

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to synthesize metal-amino acid complexes in the form of aqueous solutions to serve as new catalysts for the preparation of rigid polyurethane foams. Aqueous solutions of metal-amino acid complexes were prepared from the reaction of metal acetates with amino acids and water was used as a solvent. Metal acetates employed were copper acetate and zinc acetate. Amino acids employed were asparagine (Asn) and threonine (Thr). Both amino acids are odorless and non-toxic. UV-Vis spectroscopy, FTIR spectroscopy and mass spectrometry were used to characterize metal-amino acid complexes. Metal-amino acid complexes, namely Zn(Asn)₂, Zn(Thr)₂, Cu(Asn)₂ and Cu(Thr)₂ (where Asn …

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Characterization Of Non-Volatile Chemical Constituents In Thai Wineusing Liquid Chromatography-Tandem Mass Spectrometry, Premkamol Karapakdee Jan 2017

Characterization Of Non-Volatile Chemical Constituents In Thai Wineusing Liquid Chromatography-Tandem Mass Spectrometry, Premkamol Karapakdee

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed and validated for simultaneous determination of targeted non-volatile compounds, such as five organic acids and twenty phenolic compounds, in 19 wine samples including 2 imported red wines, 15 Thai red wines and 2 fruit wines, using the following HPLC-MS/MS conditions: a C18 analytical column and gradient elution of A: B mobile phase at flow rate 0.4 mL/min, where A and B are 0.1% v/v formic acid in water and 0.1% v/v formic acid in methanol. The limit of detection (LOD) and the limit of quantitation (LOQ) for these …

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Ferrocene-Bearing Tea Polyphenol Particles As Anticancer Drug Carriers, Punnawich Phaiyarin Jan 2017

Ferrocene-Bearing Tea Polyphenol Particles As Anticancer Drug Carriers, Punnawich Phaiyarin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Ferrocene is a redox moiety that can be positively charged upon being oxidized. Thus, it is possible to use this moiety to make a polymer platform that is redox responsive regarding their water solubility. Here we prepared polymerized EGCG nanoparticles (pEGCG) and polymerized EGCG gum (pEGCG-gum) from tea polyphenol EGCG. Ferrocene was grafted onto the polymerized tea polyphenol and the obtained polymers were allowed to self-assemble into water-insoluble and indispersible sub-micron particles. The water-insoluble ferrocene-bearing particles became water-dispersible particles with nanometer sizes upon being oxidized by hydrogen peroxide. The oxidized particles, Fc-pEG-gum can inhibit growth of HepG2 liver cancer cells …

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Synthesis And Cytotoxicity Evaluation Of Gold Nanoparticles/Pullulan Derivatives For Cancer Treatment, Sakchai Laksee Jan 2017

Synthesis And Cytotoxicity Evaluation Of Gold Nanoparticles/Pullulan Derivatives For Cancer Treatment, Sakchai Laksee

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study focused on the development of multifunctional gold nanoparticles (AuNPs) using pullulan derivatives as a trifunctional reducing, stabilizing and capping agent for targeted delivery of camptothecin (CPT) or doxorubicin (DOX) in order to enhance their efficacy and reduce side effects. The surface of AuNPs was functionalized to contain 3 beneficial components on pullulan as followed: (i) quat188 as a positive charge to increase cellular uptake and activities, (ii) para-aminobenzoic acid (PABA) as a hydrophobic molecule to enhance biocompatibility, and (iii) folic acid (FA) as a targeting ligand to bind with folate receptor on cancerous cell membranes and enhance intracellular …

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Characterization Of Non-Volatile Compounds In Tom Yum Soup Using High Performance Liquid Chromatography-Tandem Mass Spectrometry, Wanabud Wongbubpha Jan 2017

Characterization Of Non-Volatile Compounds In Tom Yum Soup Using High Performance Liquid Chromatography-Tandem Mass Spectrometry, Wanabud Wongbubpha

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, high performance liquid chromatography hyphenated with tandem mass spectrometry (HPLC-MS/MS) was developed and validated for simultaneous determination of 31 targeted non-volatile compounds, such as 2 organic acids, 20 amino acids and 9 phenolic acids, in Tom Yum ingredient, Tom Yum soup made from the fresh ingredients and commercial Tom Yum pastes, where the main Tom Yum ingredients include galangal, lemongrass, kaffir lime leaves, Bird's eye chili, lime juice and fish sauce. The following HPLC-MS/MS conditions were used: a PoroShell C18 column (4.6 x 100 mm, 2.7 µm) using a gradient elution of A:B mobile phase at a …

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Anti-Angiogenic And Cytotoxic Activities Of Rotenoids From Derris Trifoliata Lour., Yanisa Mittraphab Jan 2017

Anti-Angiogenic And Cytotoxic Activities Of Rotenoids From Derris Trifoliata Lour., Yanisa Mittraphab

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to isolate metabolites of D. trifoliata stem and to evaluate their cytotoxic and anti-angiogenic activities. Chromatographic fractionation of the EtOAc led to the isolation of eight known rotenoids (1-2, 4-6, 11-12 and 15). All compounds were first evaluated for their cytotoxicity against three cancer cell lines; human cervical carcinoma (CaSki), colon cancer (HCT-116), hepato carcinoma (Hep-G2) and normal human colon epithelial (CCD841) cells. All Compounds showed cytotoxicity against HCT-116 with IC50 ranging 0.12-11.21 µM, while they were weak or no activity against Hep-G2 and CaSKi cells. Moreover, it was found that 12a-hydroxyrotenone (11) potently inhibited migration of …

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Enhancing Captcha Using Eye Movement, Apichai Siripitakchai Jan 2017

Enhancing Captcha Using Eye Movement, Apichai Siripitakchai

Chulalongkorn University Theses and Dissertations (Chula ETD)

CAPTCHA is a method designed to prevent automatic registration and access. It can distinguish between real human and automated program (BOT). CAPTCHA connects to a server and then starts human verification process. The user must answer a question correctly or follow an instruction in order to get access to the system. However, there are some problems occurred to users. For example, the verification text is too distorted that even real humans do not understand or the effectiveness of preventing an automated computer program is doubted. From these reasons, researchers are still developing CAPTCHA to make it better and more effective. …

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Rule-Based Recommendation Model For Selecting Classifiers In Weka Based On User Specifications, Hussein Ali Azeez Jan 2017

Rule-Based Recommendation Model For Selecting Classifiers In Weka Based On User Specifications, Hussein Ali Azeez

Chulalongkorn University Theses and Dissertations (Chula ETD)

Machine learning field has many different algorithms; selecting an algorithm for non-expert user and aiming for maximizing empirical performance could be a tough task. This thesis considers the problem of selecting an algorithm based on the user specifications, for instance, training speed, memory, and interpretation. Specifically, considers the classification problem in the range of 20 models (2 meta-methods, 18 based classifiers) arising from 10 different families (Bayesian, Decision trees, Rule-based methods, Nearest neighbor methods, Logistic, multinomial regression, Neural networks, Support vector machines, Boosting, Bagging, and other ensembles), all implemented in WEKA. Different characteristics have been gathered for each model such …

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