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2018

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Articles 11551 - 11580 of 11754

Full-Text Articles in Physical Sciences and Mathematics

Carbon Sorbent Reinforced Hollow Fiber Membrane Microextraction For Determination Of Trace Polar Organic Compounds, Chanatda Worawit Jan 2018

Carbon Sorbent Reinforced Hollow Fiber Membrane Microextraction For Determination Of Trace Polar Organic Compounds, Chanatda Worawit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work presents a proof of concept that hollow fiber liquid phase microextraction reinforced with carbon nanomaterials would improve the extraction efficiency of small and relatively polar organic compounds. Several types of carbon sorbents such as graphite, graphene, carbon nanofiber were studied. In research I, the hollow fiber membrane reinforced with graphite was developed for liquid phase microextraction of trihalomethanes in water samples. Parameters affecting extraction efficiency including organic solvent as supported liquid membrane, amount of loaded graphite and extraction time were investigated and optimized. The working range of 0.2-120 µg L-1 was obtained in 10 min extraction with good …

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Development Of Electrochemical And Colorimetric Methods Using Inorganic Nanomaterials For Detection Of Biological And Environmental Compounds, Chanika Pinyorospathum Jan 2018

Development Of Electrochemical And Colorimetric Methods Using Inorganic Nanomaterials For Detection Of Biological And Environmental Compounds, Chanika Pinyorospathum

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research comprised of 2 parts including (1) lab-on-paper coupled with electrochemical method for C-reactive protein and colorimetric detection for phosphate ions and (2) the development of chromatographic techniques and its applications. In each part, it can be classified in 2 works. The first work of lab-on-paper is the electrochemical sensor that was fabricated from phosphorylcholine assembled electrodeposited gold nanoparticles onto screen-printed carbon electrode for C-reactive protein detection. Current of ferrocyanide decrease linearly when increase C-reactive protein concentration from 5.0 – 5000 µg L⁻¹. The calculated detection limit equals 1.60 µg L⁻¹. The final part of lab-on-paper is the colorimetry …

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Study Of Substitution Reaction On Ring A Of Estradiol, Chanoknun Boonyaratsewee Jan 2018

Study Of Substitution Reaction On Ring A Of Estradiol, Chanoknun Boonyaratsewee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Estradiol-conjugated anticancer drugs are the effective strategy that could specifically combat breast cancer cells, while minimizing the toxicity of the drug toward normal cells. Estradiol has been previously conjugated with drugs mostly at rings B, C and D. Functionalizations at ring A of estradiol introduce new types of conjugated drugs that could improve both the selectivity and efficiency in binding with estrogen receptor (ER). Using 4-cresol as the model, the nitration at meta-position was achieved, although with unsatisfied result of only 6% overall yield of the product. The practical results derived from diazo coupling on ortho-position of 4-cresol, which led …

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Molecularly Imprinted Polymer Modified Optical Fiber Sensor Based On Surface Plasmon Resonance Spectroscopy For Determination Of Atrazine, Chidchanok Tabtimhin Jan 2018

Molecularly Imprinted Polymer Modified Optical Fiber Sensor Based On Surface Plasmon Resonance Spectroscopy For Determination Of Atrazine, Chidchanok Tabtimhin

Chulalongkorn University Theses and Dissertations (Chula ETD)

A sensitive sensor device based on surface plasmon resonance (SPR) spectroscopy was developed on an optical fiber and made to be selective to atrazine by molecularly imprinted polymer. The SPR probe was fabricated by deposition of gold nanoparticles on the uncladed surface of an optical fiber by self-assembly method. The size and distribution of gold nanoparticle was optimized by varying the soaking time of the optical fiber. The surface was further modified for selective sensing of atrazine with the molecularly imprinted polymer (MIP). The MIP was synthesized via 2 methods, the first was thermal polymerization method, the MIP was then …

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Enzymatic Reaction Based Biosensor For Specific Detection Of Organophosphate Pesticides, Chonticha Sahub Jan 2018

Enzymatic Reaction Based Biosensor For Specific Detection Of Organophosphate Pesticides, Chonticha Sahub

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to design and develop two-biosensor platforms based on graphene quantum dots (GQDs) via enzymatic reaction for determining organophosphate pesticides (OPs). A first platform consisting of GQDs and active enzyme, GQDs/Enz platform, is simply fabricated in aqueous solution. Ongoing development of GQDs/Enz platform for effective OPs sensing by hybrid hydrogel (GQDs/Enz/Gels) was of great interest to improve the sensitivity and enzyme stability under the benefit of easy to be used for sensing approach. The GQDs/Enz and GQDs/Enz/Gels were constructed and characterized by general methods such as FT-IR, SEM and TEM. Based on the concept, H2O2 generated in situ …

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Adsorption Of Tetrachloroaluminate Ion On Graphene Quantum Dots, Fadjar Mulya Jan 2018

Adsorption Of Tetrachloroaluminate Ion On Graphene Quantum Dots, Fadjar Mulya

Chulalongkorn University Theses and Dissertations (Chula ETD)

The important thing in the mechanism of aluminium ion battery is the fast adsorption of tetrachloroaluminate [AlCl4]- on intercalation sites of bulk graphite which can increase the efficiency and lifetime of the battery. In this study, we modeled graphene quantum dots (GQDs) as cathode material. For the adsorption of [AlCl4]-, coronene (C24H12) and circumcoronene (C54H18) were used as the model of GQDs with three types of adsorption sites and standing positions. The charge of GQDs was modified to be 0 and +1 to address discharging and charging conditions. The distance between chlorine atom and carbon atom of GQDs was found …

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Green Synthesis Of Guanidines Directly From Thiourea, Jakkrit Srisa Jan 2018

Green Synthesis Of Guanidines Directly From Thiourea, Jakkrit Srisa

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, one-pot synthesis of guanidines directly from isothiocyanates using DIB (diacetoxyiodobenzene) as a desulfurizing agent under a micellar condition in water was developed. The optimization study revealed that the use of 1wt%TPGS-750-M as a surfactant with NaOH as a base at room temperature can convert aromatic isothiocyanates and varieties of amines into the corresponding guanidines in good to excellent yields (69 - 95%). This green synthetic process in water can be applied to prepare guanidine at gram-scale quantity. The aqueous micellar medium was also reusable to give relatively the similar reaction yields for at least three cycles. The …

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Application Of Capillary Electrophoresis For Determination Of Glycosaminoglycans In Biological And Cosmetic Samples, Kanokporn Chindaphan Jan 2018

Application Of Capillary Electrophoresis For Determination Of Glycosaminoglycans In Biological And Cosmetic Samples, Kanokporn Chindaphan

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, on-line preconcentration and determination of glycosaminoglycans (GAGs), especially chondroitin sulfate (CS), dermatan sulfate (DS) and hyaluronic acid (HA) using capillary electrophoresis (CE) was developed. Large-volume sample stacking using an electroosmotic flow (EOF) pump (LVSEP) technique was employed for on-line preconcentration and improvement of the detection sensitivity in CE method. Central composite design (CCD) was used to simultaneously optimize all parameters for CE separation. The optimized CE conditions were background electrolyte consisting of 200 mM sodium dihydrogen phosphate, 200 mM buthylamine and 0.5% w/v polyethylene glycol at pH 4.0 and separation voltage of -16 kV. Limit of detections …

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Electrochemical Detection Of Herbicides And Antioxidants Using Nanomaterial-Modified Electrode, Kanokwan Charoenkitamorn Jan 2018

Electrochemical Detection Of Herbicides And Antioxidants Using Nanomaterial-Modified Electrode, Kanokwan Charoenkitamorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation focused on the development of a novel nanomaterial-based electrochemical sensors for pharmaceutical and environmental applications. The research is divided into two parts. In the first part, a low-cost and disposable sensor for the simultaneous determination of coenzyme Q10 (CoQ10) and α-lipoic acid (ALA) using manganese (IV) oxide-modified screen-printed graphene (MnO2/SPGE) electrode was developed. The incorporated MnO2 in the SPGE can greatly enhance the detection performance towards the oxidation of CoQ10 and ALA. The cyclic voltammetry (CV) and square-wave anodic stripping voltammetry (SWASV) were employed to investigate the electrochemical behavior of the developed sensor and also to perform the …

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Dft And Dftb Investigations On Α–Mangostin Dye Adsorbed On Titanium Dioxide Electrode In Dsscs Application, Kanthira Kaewsud Jan 2018

Dft And Dftb Investigations On Α–Mangostin Dye Adsorbed On Titanium Dioxide Electrode In Dsscs Application, Kanthira Kaewsud

Chulalongkorn University Theses and Dissertations (Chula ETD)

Conformations of α–mangostin dye (1,3,6–Trihydroxy–7–methoxy–2,8–bis(3–methyl–2–buten–1–yl)–9H–xanthen–9–one) were studied and three conformers were found as three co-existing species in various media (in vacuo, acetonitrile and water). Geometries, electronic structures and UV–Vis spectra of all conformers in various media have been obtained using density functional theory (DFT) and time–dependent DFT (TD–DFT) methods. The conformers of α–mangostin dye were inspected as photosensitizers for application in dye sensitized solar cells (DSSCs) and their light–harvesting efficiencies (LHEs) within the range of 0.6757–0.7556 eV (in vacuo), 0.8286–0.8466 eV (in acetonitrile) and 0.8288–0.8465 eV (in water) were obtained. The open circuit voltage (VOC) of three conformers within the …

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Speciation Of Arsenic Using Sulfur Containing Ligand And Cotton Wool By Icp-Oes, Kavee Triteeyaprasert Jan 2018

Speciation Of Arsenic Using Sulfur Containing Ligand And Cotton Wool By Icp-Oes, Kavee Triteeyaprasert

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to develop a method for speciation of arsenic species including As(III) and As(V) in environmental samples. Cotton wool and sulfur containing ligands including ammonium pyrrolidinedithiocarbarmate (APDC), L–cysteine and diethyldithiocarbamic acid were used in a solid phase extraction and determination of arsenic by using inductively coupled plasma optical emission spectrometry. The separation parameters were studied including pH, ligand concentration, cotton amount, type of eluents and flow rate. It was found that at pH 2, 0.1% APDC concentration and 0.5 g of cotton, As(III) could form complex with APDC (As(III) – APDC) and was separated from As(V) by using …

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Green Synthesis Of Gold Nanoparticles Using Wax Leaved Climber Cryptolepis Buchanani Latex And Biological Activities, Kittiphong Tongsuk Jan 2018

Green Synthesis Of Gold Nanoparticles Using Wax Leaved Climber Cryptolepis Buchanani Latex And Biological Activities, Kittiphong Tongsuk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Gold nanoparticles (AuNPs) is the one of nanodrug carriers that have been popular in the current trend. To prepare AuNPs for biomedical applications, many techniques have been developed. However, both physical and chemical methods may cause energy consuming and toxic residues so green synthesis would be the most appropriate method for the preparation of AuNPs. The green synthesis of AuNPs could be provided by utilizing of fungi, bacteria and plant. In this work, we focused to use plant latex as reducing and stabilizing agents for the synthesis of AuNPs. The latex was collected from Cryptolepis buchanani, a folk medicinal plant …

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Sequence Specific Nucleic Acid Sensing By Pyrrolidinyl Peptide Nucleic Acid And Nanomaterials, Kriangsak Faikhruea Jan 2018

Sequence Specific Nucleic Acid Sensing By Pyrrolidinyl Peptide Nucleic Acid And Nanomaterials, Kriangsak Faikhruea

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, fluorescence and colorimetric nucleic acid sensing platforms based on pyrrolidinyl peptide nucleic acid (acpcPNA) probe and nanomaterials including graphene oxide (GO), reduced graphene oxide (rGO), gold nanoparticles (AuNPs), and silver nanoparticles (AgNPs) were developed. The acpcPNA probe was modified by multiple lysine residues to provide positive charges which enhanced the adsorption of the probe to various types of nanomaterials. In fluorescence detection mode, this results in higher quenching efficiency, resulting in lower background signal. Recovery of the quenched fluorescence signal was achieved upon hybridization with the complementary DNA/RNA target due to the displacement of the probe from …

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C-O Bond Formation On C-5 Of 2,4-Diaminopyrimidines, Natthakorn Uppatam Jan 2018

C-O Bond Formation On C-5 Of 2,4-Diaminopyrimidines, Natthakorn Uppatam

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work aims to find a robust oxidation condition that can efficiently convert 2,4-diaminopyrimidines to its C5-hydroxylated derivative. Although Boyland-Sims oxidation of these substrates has been reported, this procedure suffers low yield and poor reproducibility. The conditions for Boyland-Sims oxidation of 2,4-diaminopyrimidines were thus re-optimized. The parameters that could affect the yields of the 5-hydroxy products were investigated using 2,4-diamino-6-ethylpyrimidine as a model compound. The reactions were performed at 0.10 mmol scale of the starting pyrimidine. The yields of the products were monitored by 1H NMR spectroscopy with reference to an internal standard. The reaction was reproduced at larger scale …

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Synthesis Of Hydroxyapatite Nanoparticles For Polynucleotides Delivery In Dentistry, Natthaya Thepphanao Jan 2018

Synthesis Of Hydroxyapatite Nanoparticles For Polynucleotides Delivery In Dentistry, Natthaya Thepphanao

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hydroxyapatite (HAp) nanoparticles-based miRNA delivery system has emerged as a promising therapeutic agent for bone regeneration application. In order to achieve high therapeutic performance, the development of HAp functions remains challenging. This study describes the influence of HAp characters on their biological activities with osteoblast cell by synthesized different sizes of rod-like HAp with 150-200 and 100 nm in size and the different shape of elongated particles with 100-150 nm in size. A comparison was carried out on cytotoxicity, cellular uptake, and miRNA binding capacities. The elongated and rod-like shapes of 100-150 nm illustrated the high cell viability, and interestingly, …

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Glycosylation Of Thioglycosides With Bromodiethylsulfonium Bromopentachloroantimonate As Novel Activator, Ladawan Punrum Jan 2018

Glycosylation Of Thioglycosides With Bromodiethylsulfonium Bromopentachloroantimonate As Novel Activator, Ladawan Punrum

Chulalongkorn University Theses and Dissertations (Chula ETD)

Glycosylation is an important reaction in carbohydrate synthesis of complex molecules such as oligosaccharides, glycoproteins, and glycolipids. Thioglycosides are widely used as precursors in oligosaccharide synthesis due to their ease of preparation, high stability towards protecting group manipulations and variety of activation methods. Recently, bromodiethylsulfonium bromopentachloroantimonate (BDSB) was reported as a novel source of highly electrophilic bromine. It was used to efficiently initiate cation-π cyclizations of polyene at low temperature. Herein, we report a chemical glycosylation of thioglycosides activated by BDSB. Firstly, armed and disarmed glycosyl donors and glycosyl acceptors were synthesized by using modified previous method. Next, several reaction …

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Metalloporphyrin-Sensitized Titania/Silica/Iron Oxide Nanocomposites And Their Photocatalytic Activities, Padtaraporn Chanhom Jan 2018

Metalloporphyrin-Sensitized Titania/Silica/Iron Oxide Nanocomposites And Their Photocatalytic Activities, Padtaraporn Chanhom

Chulalongkorn University Theses and Dissertations (Chula ETD)

New nanomaterials of the magnetic visible light active photocatalysts, tetra(4-carboxyphenyl)porphyrin (TCPP) with different metals [Mn(II), Fe(III), Cu(II), Zn(II) and metal-free] in the center adsorbed on titania-silica-iron oxide superparamagnetic composites (TSI) were synthesized successfully. The photocatalytic activities in methylene blue (MB) degradation were determined under incandescent lamp for 3 h. Their characteristics have been identified using UV-visible spectroscopy, X-ray diffractometry (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The photodegradation results revealed that the metalloporphyrin sensitization helped TSI to absorb the light in visible region. Titania-silica-iron oxide nanomaterials with copper(II) tetra(4-carboxyphenyl)porphyrin (CuTCPP) can significantly …

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Molecular Simulations Of Voltage-Gated Proton-Selective Channel, Panisak Boonamnaj Jan 2018

Molecular Simulations Of Voltage-Gated Proton-Selective Channel, Panisak Boonamnaj

Chulalongkorn University Theses and Dissertations (Chula ETD)

Voltage-gated proton-selective channels (Hv1) are a membrane protein that permeates proton across cell membranes. They play an important role in various physiological processes. Hv1 was found as a dimer in membranes. Molecular mechanisms underlying the proton conduction of Hv1 have been a subject of intense research but is still remained unclear. In this study, molecular dynamics (MD) simulations of Hv1 were carried out to gain better understanding of the structure-function relationship. The first part of this thesis involved with an investigation of the role of the C-terminal domain (CTD) in stabilizing the dimer structure of Hv1. MD data showed the …

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Fluorescent Sensors From Salicylaldimine Derivatives For Metal Ions, Phoom Sangsuwan Jan 2018

Fluorescent Sensors From Salicylaldimine Derivatives For Metal Ions, Phoom Sangsuwan

Chulalongkorn University Theses and Dissertations (Chula ETD)

An in-situ forming and sensing was developed as a high-throughput screening of fluorescent chemosensors for metal ions. The 45 salicylaldimines, formed in-situ from the condensation between 5 salicylaldehydes and 9 amines, in 96 well-plates were photographed under black light along with the 5 salicylaldehydes in the absence and presence of 18 metal ions. The library of fluorescence response images of these 50 chemosensors were processed into RGB values. The PCA of theΔRGB, the differences between those of images with and without the metal ions, showed 9 sensors with normalized loading value over 70%. The sensor array constructed from these 9 …

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Hybrid Materials From Covalent Organic Frameworks And Ionic Liquids, Ranida Maliyaem Jan 2018

Hybrid Materials From Covalent Organic Frameworks And Ionic Liquids, Ranida Maliyaem

Chulalongkorn University Theses and Dissertations (Chula ETD)

Covalent organic frameworks (COFs) are new type material, whereby their wide range of properties derived from the chemistry of frameworks and their regular porosity. Here in, we reported the successful syntheses of the novel hybrid materials between porous COF material and ionic liquids (ILs). The crystalline porous powder of boroxine‑based COF, so called COF‑5, is reproducible via a condensation reaction between hexahydroxyltriphenylene and phenyldiboronic acid under a mild condition using a conventional heating method. The as‑synthesized COF-5 was characterized with PXRD, FT-IR, TGA and BET techniques, showing that the material contained 1D regular channels caused by π-π stacking of the …

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Detection Of Sulfonamide Residues By Paper Spray Mass Spectrometry, Surased Suraritdechachai Jan 2018

Detection Of Sulfonamide Residues By Paper Spray Mass Spectrometry, Surased Suraritdechachai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Sulfonamide antibiotics are commonly used veterinary drugs in livestock to prevent or treat infectious diseases. Their residues in food are of concern since they can cause adverse health effects and development of bacterial resistance. In this work, a practical method for detection and quantification of sulfamethazine, one of sulfonamide antibiotics, in pig body fluid samples is developed via the combination of simple extraction and paper spray mass spectrometry. The method required minimal sample preparation and low analysis time while providing high sensitivity and accuracies in pig whole blood (LOD = 10.1 ng/mL, %recovery = 95.4-104.1%), pig serum (LOD = 4.6 …

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Fabrication And Mechanical Properties Of Hyaluronic Acid Microneedle Arrays For Transdermal Drug Delivery, Teeranut Rutwaree Jan 2018

Fabrication And Mechanical Properties Of Hyaluronic Acid Microneedle Arrays For Transdermal Drug Delivery, Teeranut Rutwaree

Chulalongkorn University Theses and Dissertations (Chula ETD)

Dissolvable microneedles have been widely investigated as an alternative of hypodermic injection or other drug delivery methods. Various polymers have been used to fabricate microneedles. Type of polymers affects mechanical properties and dissolution rate of microneedles. In this study, five formulations of hyaluronic acid (HA)/ polyvinylpyrrolidone (PVP) composite microneedle patches (HA/PVP at 100/0, 75/25, 50/50, 25/50, 0/100) were fabricated. The crosslinked HA microneedles were also fabricated. Mechanical properties of the obtained microneedles were determined by universal testing machine and durometer. The skin-penetration ability and dissolution rate of HA/PVP microneedles were also investigated using porcine skin. The results show that microneedle …

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Synthesis Of Halogenated Flavonoids As Anti-Dengue Agents, Thao Huynh Nguyen Thanh Jan 2018

Synthesis Of Halogenated Flavonoids As Anti-Dengue Agents, Thao Huynh Nguyen Thanh

Chulalongkorn University Theses and Dissertations (Chula ETD)

Flavonoids have been recognized as promising compounds with various bioactivities. Certain flavonoid derivatives exhibited more potent activities than their parent compounds. Recently, halogenated flavonoids have been addressed for their anti-dengue activity. In this research, a series of twenty-two brominated and iodinated flavonoid derivatives were synthesized and explored for dengue infection inhibition. Seventeen derivatives have been investigated for the first time. 8-Bromobaicalein, 6,8-dibromopinocembrin, 6,8-dibromopinostrobin, 6,8-diiodopinostrobin were disclosed as effective and non-toxic anti-dengue agents. These compounds displayed remarkably low EC50 as well as high CC50, which could be considered as potent therapeutic agents. Moreover, the preliminary screening on brominated O7-ether chrysins discovered …

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Benzimidazole Derivatives Of Perylene Diimide For Organic Field-Effect Transistor, Tianchai Chooppawa Jan 2018

Benzimidazole Derivatives Of Perylene Diimide For Organic Field-Effect Transistor, Tianchai Chooppawa

Chulalongkorn University Theses and Dissertations (Chula ETD)

The poor solubility of perylene derivatives has been a key factor that prohibits the application of these thermally stable compounds in organic field-effect transistors (OFET) devices. In this research, the effort to enhance the solubility and exploring FET property of benzimidazole derivatives of perylene diimide were investigated. The perylene diimide core structure was functionalized by aryloxy moieties. Unfortunately, the isomeric products were still poorly soluble in common organic solvents, which made them impossible to separate and purify. Thus, the synthetic plan and goal were completely revised to the benzotriazatruxene derivatives, which were highly soluble in organic solvents such as dichloromethane …

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Green Synthesis Of Gold Nanoparticles Using Natal Lily Crinum Moorei Extract And Biological Activities, Warinda Marujiwat Jan 2018

Green Synthesis Of Gold Nanoparticles Using Natal Lily Crinum Moorei Extract And Biological Activities, Warinda Marujiwat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Crinum moorei as medical herb has different pharmacological activities such as anti-cancer and anti-inflammatory properties. Gold nanoparticle (AuNP) is an interesting anti-cancer drug carrier which can solve anti-cancer drug's problems with good biocompatibility, non-toxicity and suitable size for the intracellular uptake to treat to the target cells. From the beginning, other reducing agents were used to synthesize AuNPs. However, they lead to the contamination of chemicals on AuNP's surfaces which limits the medical application or long process and time consuming. Therefore, plant extracts were studied to make a remarkable dual function: the synthesized AuNPs agent and drug agent. In this …

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Development Of Headspace-Solid Phase Microextraction And Gas Chromatography-Mass Spectrometry/Olfactometry For Analysis Of Volatile Compounds From Chicken Products, Wongkanok Yoosong Jan 2018

Development Of Headspace-Solid Phase Microextraction And Gas Chromatography-Mass Spectrometry/Olfactometry For Analysis Of Volatile Compounds From Chicken Products, Wongkanok Yoosong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Gas chromatography-mass spectrometry/olfactometry coupled headspace solid phase microextraction (HS-SPME-GC-MS/O) was applied to analysis of volatile compounds from raw chickens and boiled chickens. The HS-SPME was 50/30 mm DVB/CAR/PDMS. The extraction temperature of boiled chicken was 50 °C for 30 min and raw chicken were extracted at room temperature. The SPME Probes were analyzed by GC-MS with a HP-5MS capillary column. 16 volatile compounds were identified in the boiled chickens in four chemical classes including aldehydes, aromatic hydrocarbon, alcohols and ketones and 20 volatile compounds were identified in raw chickens in three chemical classes including aldehydes, alcohols and esters. The identification …

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Synthesis And Antidiabetic Activity Of Furofuran Lignans Containing Multiphenolic Groups, Titiruetai Doungwichitrkul Jan 2018

Synthesis And Antidiabetic Activity Of Furofuran Lignans Containing Multiphenolic Groups, Titiruetai Doungwichitrkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Synthesis of furofuran lignans containing multiphenolic groups (6-12) was carried out. The starting material samin (5) was obtained by acid hydrolysis of sesamin (2), which was isolated from sesame seed oil. A series of target lignans were synthesized from samin (5) and a varity of phenolics through Friedel-Crafts reaction, yielding desired products (6). To increase number of hydroxy moieties on the synthesized lignans, oxidative reaction using lead (IV) tetraacetate was performed. Removal of methylenedioxy of furofuran lignans containing a phenolic moiety produced unexpected products which contains para-quinone together with ortho-dihydroxy moieties on furofuran core structures (8-9). Consequently, to avoid oxidation …

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A Deep Relation Extraction From Biomedical Texts With Attention Mechanisms And Domain-Specific Contextual Representations, Amarin Jettakul Jan 2018

A Deep Relation Extraction From Biomedical Texts With Attention Mechanisms And Domain-Specific Contextual Representations, Amarin Jettakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

The biomedical relation extraction (RE) tasks aim to study the interaction between pre-defined entities from biomedical literature: Bacteria Biotope (BB) and Drug-Drug interactions (DDI) tasks. Some previous investigations have used feature-based models; others have presented deep-learning-based models such as convolutional and recurrent neural networks used with the shortest dependency paths (SDPs). Although SDPs contain valuable and concise information, sections of significant information necessary to define bacterial location relationships are often neglected. In addition, the traditional word embedding used in previous studies may suffer from word ambiguation across linguistic contexts. Here, we present a deep learning model for biomedical RE. The …

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Knowledge Sharing In Cooperative Compact Genetic Algorithm, Orakanya Gateratanakul Jan 2018

Knowledge Sharing In Cooperative Compact Genetic Algorithm, Orakanya Gateratanakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

The compact genetic algorithm is derived from the genetic algorithm in which the population is represented by the probabilistic vector. To improve the search capability and avoiding local minima, parallelization has been employed where many search processes are deployed concurrently. In order to coordinate the work of multiple processes, knowledge sharing is necessary. Multiple processes share their probabilistic vectors partially. To escape from local minima the restart step is introduced. The experiment compares the proposed algorithm with two other competitive algorithms using Traveling Salesman problem, Bin Packing problem, Subset Sum problem, and Knapsack problem. The results show that the proposed …

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Explicit Energy-Minimal Short-Term Path Planning For Collision Avoidance In Bidirectional Crowd Simulation, Saran Sillapaphiromsuk Jan 2018

Explicit Energy-Minimal Short-Term Path Planning For Collision Avoidance In Bidirectional Crowd Simulation, Saran Sillapaphiromsuk

Chulalongkorn University Theses and Dissertations (Chula ETD)

การหาเส้นทางการเดินในระยะยาวรวมกับการหลบหลีกสิ่งกีดขวางรอบๆ เป็นวิธีทั่วไปที่ถูกนำมาใช้ในการจำลองการเคลื่อนไหวของตัวตนจำลองจากตำแหน่งหนึ่งไปยังอีกตำแหน่งหนึ่ง โดยไม่ให้เกิดการชนกันระหว่างตัวตนจำลองกับวัตถุในฉากและระหว่างตัวตนจำลองด้วยกันเอง วิธีนี้สามารถให้ผลการจำลองที่ดีในสถานการณ์ที่ผู้คนสามารถเดินได้หลายทิศทาง แต่ในสถานการณ์ที่ผู้คนถูกจำกัดทิศทางการเดินให้เหลือเพียงหนึ่งหรือสองทิศทางนั้น ปรากฏว่าตัวตนจำลองมีลักษณะการเดินที่ผิดธรรมชาติ เช่น เดินเข้าไปติดและอยู่นิ่งระหว่างตัวตนจำลองสองตัวที่เดินสวนมาหรือเดินเข้าไปในพื้นที่ที่แออัดหรือมีกลุ่มคนเยอะๆ ทั้งๆที่ยังมีเส้นทางเดินที่ทำให้ตัวตนจำลองสามารถเดินหลบหลีกไปได้ ลักษณะเช่นนี้เกิดขึ้นบ่อยและเห็นได้ชัดในสถานการณ์แบบสองทิศทาง งานวิจัยนี้จึงได้เสนอขั้นตอนในการหาเส้นทางในระยะสั้นเพื่อขจัดความบกพร่องของพฤติกรรมการเดินของตัวตนจำลองในสถานการณ์แบบสองทิศทางนี้ขึ้น โดยใช้สมการพลังงานทางชีวกลศาสตร์ของการเดินเข้ามาเป็นตัวแปรที่บังคับให้ตัวตนจำลองมีความฉลาดในการเลือกเส้นทางในระยะสั้นได้ ผลลัพธ์ของการวิเคราะห์สมการพลังงานนั้น ช่วยบ่งบอกลักษณะของการเลือกเส้นทางการเดินที่ดีที่สุด โดยคำนึงถึงความเร็วที่ใช้เพื่อให้ประหยัดพลังงานที่สุด พร้อมๆ กับถึงจุดหมายปลายทางให้เร็วที่สุดด้วย นอกจากนี้ยังพบว่าการนำวิธีที่เสนอนี้ไปใช้ในสถานการณ์แบบหลายทิศทางนั้น ตัวตนจำลองสามารถหาเส้นทางที่เหมาะสมกว่าเมื่อเทียบกับวิธีก่อนอีกด้วย ยกตัวอย่าง เช่น ตัวตนจำลองสามารถเดินแทรกเข้าไปในช่องแคบๆ ของขบวนพาเหรดได้ เป็นต้น

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