Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

2017

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 154531 - 154560 of 160903

Full-Text Articles in Entire DC Network

Synthesis And Optical Properties Of Pyrrolidinyl Peptide Nucleic Acid Carrying Fluorescence Nucleobases, Duangrat Nim-Anussornkul Jan 2017

Synthesis And Optical Properties Of Pyrrolidinyl Peptide Nucleic Acid Carrying Fluorescence Nucleobases, Duangrat Nim-Anussornkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Pyrrolidinyl peptide nucleic acid bearing D-prolyl-2-aminocyclopentanecarboxylic acid backbone (acpcPNA) is a nucleic acid mimic that shows superior binding affinity, stability and specificity to complementary DNA than the original PNA. This research focuses on the development of hybridization responsive fluorescence acpcPNA probes bearing fluorescent nucleobases that exhibit fluorescence increase upon hybridization to a specific nucleobase in the DNA target. The acpcPNA carrying the fluorescent nucleobases were synthesized via two different approaches, namely 1) pre-synthesized fluorescence PNA monomer as a building block that was subsequently incorporated into the PNA by solid phase synthesis and 2) post-synthetic modification of acpcPNA carrying a reactive …

Go to article

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 …

Go to article

Synthesis Of Cationic Cdse/Zns Quantum Dots And Applications In Dna Detection, Jamornpan Yangcharoenyuenyong Jan 2017

Synthesis Of Cationic Cdse/Zns Quantum Dots And Applications In Dna Detection, Jamornpan Yangcharoenyuenyong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Semiconductor nanoparticles or quantum dots (QDs), especially CdSe/ZnS QDs, are of great interest in bioapplications due to their unique size-dependent optical properties and photo-stability. One of the plausible applications of QDs is DNA detection using QDs as a novel fluorescence tool for sensing of DNA using the electrostatic interaction between negative charge of DNA and positive charge on QDs surface. In this work, CdSe/ZnS QDs were synthesized using a hot-solution decomposition process resulting in hydrophobic CdSe/ZnS QDs. To obtain water-soluble and cationic QDs, the surface of QDs were modified with poly(ethylene)imine (PEI) via micelle formation. Because of hydrophilicity of PEI …

Go to article

Enantiomeric Separation Of Alcohols By Gas Chromatography And Qspr Study To Predict Enantiomeric Separation, Kittiyakorn Toboonpha Jan 2017

Enantiomeric Separation Of Alcohols By Gas Chromatography And Qspr Study To Predict Enantiomeric Separation, Kittiyakorn Toboonpha

Chulalongkorn University Theses and Dissertations (Chula ETD)

Enantiomeric separation of 55 alcohols (13 aliphatic alcohols and 42 alcohols of aromatic structure) was studied by gas chromatography using octakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-γ-CD (or GSiAc) as a chiral stationary phase. For separation under temperature program, 44 alcohols could be enantioseparated. The only aliphatic alcohol that could be completely separated into their enantiomers was 2-hexanol. Twenty-five alcohols, based on 1-phenylethanol, were selected to study under isothermal conditions. For halogen-substituted 1-phenylethanols, temperature strongly affected enantioselectivities of para-substituted alcohols. However, temperature affected enantioselectivities of methyl- or trifluoromethyl-substituted alcohols at ortho-position more than other positions. For para-substituted alcohols, enantioseparations could be improved with the substituent in …

Go to article

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 …

Go to article

Adsorption Of Paraquat Herbicide In Water Using Humic Acids Supported On Sludge From Tap Water Production Entrapped In Alginate Beads, Munlika Suksai Jan 2017

Adsorption Of Paraquat Herbicide In Water Using Humic Acids Supported On Sludge From Tap Water Production Entrapped In Alginate Beads, Munlika Suksai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Adsorption of paraquat in water using humic acids supported on sludge from tap water production or alum sludge entrapped in alginate beads has been studied. The adsorbent was characterized by Fourier transform infrared spectroscopy showing that it composes of humic acids, alum sludge and alginate in beads. Afterwards, the type and amount of adsorbents were studied including bare alginate beads, humic acids-alginate beads, alum sludge-alginate beads, alum sludge-humic acids-alginate beads-1 and alum sludge-humic acids-alginate beads-2. These adsorbents were subjected to the paraquat adsorption study in aqueous solutions. The results showed that all adsorbents can adsorb paraquat, especially the alum sludge-humic …

Go to article

New Edta-Based Drug Delivery Carrier, Nathapong Pangkom Jan 2017

New Edta-Based Drug Delivery Carrier, Nathapong Pangkom

Chulalongkorn University Theses and Dissertations (Chula ETD)

Most of the anticancer drugs are insoluble in water, unspecified to target site and degradable under acidic conditions in the stomach, resulting in decreasing their activities and increasing the side effects. To overcome these problems, drug delivery carriers were used to overcome these problems. Most of the drug delivery carriers were prepared by polymeric micelle systems. However, that of polymeric micelle systems are difficult to synthesize into the random polymers, where different units are aligned on a polymer chain in a random manner, immature drug-incorporation technology and possible chronic liver toxicity due to slow metabolic process. Therefore, the enhancement of …

Go to article

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 …

Go to article

Characterization Of Aroma-Active Volatile Compounds In Tom Yum Soup By Gas Chromatography-Mass Spectrometry Combined With Sensory Evaluation Techniques, Pannipa Janta Jan 2017

Characterization Of Aroma-Active Volatile Compounds In Tom Yum Soup By Gas Chromatography-Mass Spectrometry Combined With Sensory Evaluation Techniques, Pannipa Janta

Chulalongkorn University Theses and Dissertations (Chula ETD)

Gas chromatography-mass spectrometry/olfactometry coupled with headspace-solid phase microextraction (HS-SPME-GC-O/MS) was applied for the characterization of volatile compounds in Tom Yum soup and its individual ingredients including lemongrass, kaffir lime leaf, chili, fish sauce and lime juice. Using HS-SPME with a 50/30 µm DVB/CAR/PDMS fiber and an extraction temperature of 40 °C for 50 min, along with an HP-5MS capillary column programmed from 50 to 200 °C at 3 °C/min and an MS electron impact ionization at -70 eV, 101 peaks in the HS-SPME-GC-MS chromatogram of Tom Yum soup were detected, and 96 volatile compounds were identified including alcohols, aldehydes, esters, …

Go to article

Colorimetric Detection Of Cyanide Ions Using Complex Formation And Ctab-Coated Silica, Patita Salee Jan 2017

Colorimetric Detection Of Cyanide Ions Using Complex Formation And Ctab-Coated Silica, Patita Salee

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research presents a new colorimetric method of cyanide detection in solution and water samples based on the extraction of dicyano-bis-(1,10-phenanthroline)-iron(II) complex onto CTAB-coated silica. The complex was formed at pH 10 by using phosphate buffer via the complex formation between tris-(1,10-phenanthroline)-Iron(II) (ferroin) with cyanide ions in CTAB media. When the complex was extracted onto CTAB-coated silica, it resulted in a color change of the material from pale yellow to purple. The changing of color corresponded to cyanide concentration which could be observed by naked-eyes and the color intensity was determined by Image J. The effects of various parameters were …

Go to article

Fabrication Of Silver Nanofilament Based On Silver Sulfide Solid Electrolyte For Tip-Enhanced Raman Spectroscopy, Phichaya Fueaimi Jan 2017

Fabrication Of Silver Nanofilament Based On Silver Sulfide Solid Electrolyte For Tip-Enhanced Raman Spectroscopy, Phichaya Fueaimi

Chulalongkorn University Theses and Dissertations (Chula ETD)

Surface science analysis is the crucial fundamental of nanoscale study. The techniques combined morphological and compositional study on the surface are the promising technique. Tip-enhanced Raman spectroscopy (TERS) is the coupling of atomic force microscopy (AFM) and Raman spectroscopy which give the 3D- images and bonding information in ambient conditions. Furthermore, TERS tip is an ideal tool for the high enhancement and spatial resolution. Nowadays, TERS tip fabrication is still challenged. There are three main challenges that are high enhancement factor of the TERS tip, reproducibility of the tip and in-depth understanding of TERS process. We introduce the simple method …

Go to article

Fluoride Encapsulation In Calcium Matrix, Piyada Dissara Jan 2017

Fluoride Encapsulation In Calcium Matrix, Piyada Dissara

Chulalongkorn University Theses and Dissertations (Chula ETD)

Fluoride ion (F-) is an important ingredient in a toothpaste. It protects caries by reacting with hydroxyapatite [Ca10(PO)4(OH)2] in tooth enamel to form insoluble fluorapatite [Ca10(PO)4(F)2]. Unfortunately, F- also easily interacts with calcium species in a toothpaste, and then it is deactivated. In this work, we focus on the encapsulation of F- in a shellac bead by using a simple extrusion method. To construct shellac beads, an aqueous solution of F- is injected into an ethanolic solution of shellac. The shellac beads are formed due to insolubility of shellac in water. Then, the beads are transferred into DI water for …

Go to article

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 …

Go to article

Colorimetric Detection Of Cysteine Using Silver-Hydroxyapatite Nanoparticles, Retno Prasetia Jan 2017

Colorimetric Detection Of Cysteine Using Silver-Hydroxyapatite Nanoparticles, Retno Prasetia

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cysteine is a sulphur-containing amino acid that acts as an effective antioxidant in human body. An excessive amount of cysteine leads to cystine formation that causes the stone formation in kidney, bladder, and ureters. A new method was developed for detection of cysteine in urine samples based on the aggregation of silver nanoparticles (AgNPs) on Hydroxyapatite (HAp) in the presence of cysteine. Transmission Electron Microscope (TEM) was used to observe the morphology of prepared HAp and AgNPs on HAp. The presence of cysteine of different concentrations resulted in different cluster sizes of AgNPs on HAp and hence different solid color. …

Go to article

Synthesis And Supramolecular Polymerization Of Peptide Nucleic Acid-Containing Monomer, Ruttiyakorn Donthongkwa Jan 2017

Synthesis And Supramolecular Polymerization Of Peptide Nucleic Acid-Containing Monomer, Ruttiyakorn Donthongkwa

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nucleobase-induced self-assembly interaction, have gained much attention as potential non-covalent driving force for generating interesting assembled structures. Pyrrolidinyl peptide nucleic acid (PNA), with (2′R,4′R)-prolyl/(1S,2S)-2-aminocyclopentanecarboxylic acid backbone (acpcPNA) has shown the recognition with complementary nucleic acids following Watson-Crick base rules. Another PNA system having different stereochemistry on proline ring with a backbone of (2′R,4′S)-prolyl/(1S,2S)-2-aminocyclopentanecarboxylic acid backbone (epi-acpcPNA) can undergo self-pairing. Here in this work, both acpcPNA- and epi-acpcPNA-functionalized monomers consisting of two PNA segments joined together by a flexible polyethylene glycol linker were prepared on solid support, purified by high performance liquid chromatography (HPLC) and characterized by MALDI-TOF mass spectrometry. The …

Go to article

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 …

Go to article

Functionalization Of Chemical Vapor Deposition-Grown Graphene, Shobnibhit Chatmaneerungcharoen Jan 2017

Functionalization Of Chemical Vapor Deposition-Grown Graphene, Shobnibhit Chatmaneerungcharoen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Graphene has been a wonder material since its discovery in 2004. Due to its interesting properties such as excellent thermal and electrical conductivities, flexibility and high strength, many researchers around the globe have turned their attention to this carbon allotrope. To synthesize graphene with high quality, chemical vapor deposition (CVD) is an industrially feasible method. Generally, methane is the most widely used carbon precursor. However, high purity grade is expensive in Thailand. Instead, acetylene should be a possible replacement. Moreover, operating CVD at atmospheric pressure would also dramatically reduce the cost. Still, growth conditions need to be optimized for new …

Go to article

Bioactive Compounds From Lichens And Mycobionts In Trypetheliaceae Family, Suekanya Jarupinthusophon Jan 2017

Bioactive Compounds From Lichens And Mycobionts In Trypetheliaceae Family, Suekanya Jarupinthusophon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Chemical constituents of two lichens Marcelaria cumingii and Trypethelium subeluteriae, and four cultured mycobionts from M. cumingii, T. platystomum, T. eluteriae and Trypethelium sp. (Trypetheliaceae) were explored. Their secondary metabolites were structurally elucidated by spectroscopic methods as xanthones, anthraquinones, naphthoquinones and phenalenones. Lichexanthone, parietin, xanthorin and emodin were disclosed as constituents of lichens M. cumingii. Whereas, two anthraquinones: parietin and emodin could be isolated from T. subeluteriae together with another anthraquinone, haematommone. The chemical compositions of four cultured mycobionts were found to totally differ from those from lichen. The phenalenone bipolaride C was derived from T. platystomum while two 1,2-naphthoquinones, …

Go to article

Colorimetric Determination Of Thiocyanate Ion Using Modified Polymer Resins, Sujinda Khaosaard Jan 2017

Colorimetric Determination Of Thiocyanate Ion Using Modified Polymer Resins, Sujinda Khaosaard

Chulalongkorn University Theses and Dissertations (Chula ETD)

A new method for thiocyanate determination in milk samples based on the formation of dithiocyanato dipyridine copper(II) [Cu(SCN)2(Py)2] complex on polymer resin surface is proposed. Amberlite XAD-7 resin on was modified with copper-pyridine complex and used as the material for detection. The color of resin changed from blue to green with the increase of thiocyanate concentration. It could be observed by naked-eye and the color intensity used as quantitative data was measured via Image-J software. The effect of various parameters was investigated including Cu2+ concentration, time for resin modification with reagents, sample volume, detection time and pyridine volume. Under the …

Go to article

Composite Fiber Of Poly(3,4-Ethylenedioxythiophene) And Derivative For Electrochemical Applications, Thanarath Pisuchpen Jan 2017

Composite Fiber Of Poly(3,4-Ethylenedioxythiophene) And Derivative For Electrochemical Applications, Thanarath Pisuchpen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Poly(3,4-ethylenedioxythiophene) (PEDOT) is a conducting polymer that has many advantages including high conductivity, high transparency, and good stability. Despite its advantages, its insolubility and lack of active groups for further functionalization remain the major obstacles for its applications. In this work, polymer/PEDOT composite fibers were fabricated using solid state polymerization of 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) and its derivative containing carboxylic acid (DBEDOT-C4-COOH) in combination with electrospinning technique to ensure good dispersion of PEDOT in polymer matrix. The well-dispersed electrospun PEDOT/polymer composite the fiber mats were used to modify the screen-printed carbon electrode as testing models. The PEDOT/poly(vinyl alcohol) (PVA) composite fiber fabricated …

Go to article

Design And Synthesis Of Selenium Nanoparticles To Overcome Multiple Drug Resistance Of Cancer Cells, Urarika Luesakul Jan 2017

Design And Synthesis Of Selenium Nanoparticles To Overcome Multiple Drug Resistance Of Cancer Cells, Urarika Luesakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objective of this research is to synthesize selenium nanoparticles (SeNPs) stabilized by chitosan as a drug carrier for delivery doxorubicin to overcome drug-resistant in cancer cells. One important mechanism of multidrug resistance (MDR) includes decreased drug influx and increased drug efflux, leading to insufficient drug concentration to kill cancer cells. Therefore, to overcome MDR by increasing cellular uptake, the surface of SeNP was functionalized to provide 3 structural features: (i) a positive charge to improve their solubility, (ii) gallic acid, a hydrophobic molecule to enhance biocompatibility and (iii) folic acid, a targeting molecule to target cancer cells and enhance …

Go to article

Synthesis Of Alternating Conjugated Copolymers From Direct C-H Arylation, Vasin Thummasorn Jan 2017

Synthesis Of Alternating Conjugated Copolymers From Direct C-H Arylation, Vasin Thummasorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Synthesis of conjugated polymers via Direct Hetero Arylation Polycondensations (DHAPs) through palladium catalyzed cross-coupling polymerization was investigated. This synthetic method has advantages over traditional method by omitting the preactivation of one of the coupling partner, minimizing production of toxic wastes, side products, and cost. We obtained the donor-acceptor copolymer 4 from DHAPs of 2,5-dichloro-3,4-dinitrothiophene (DCDNT) and 3,4-ethylenedioxythiophene (EDOT) as orange solid in 31.7% yield. Copolymer 5 was also obtained using the same methodology from EDOT and 1,4-dibromo-2,5-bis(octyloxy)benzene (DBOB) as the precursors, in which the best result was 86% yield. The optimized DHAP condition was used to prepare copolymers 6 (from …

Go to article

Synthesis Of Thiofuranosides By Dehydrative Glycosylation In Micellar Media, Trichada Ratthachag Jan 2017

Synthesis Of Thiofuranosides By Dehydrative Glycosylation In Micellar Media, Trichada Ratthachag

Chulalongkorn University Theses and Dissertations (Chula ETD)

Green and aqueous-based dehydrative glycosylation of thiofuranosides in micellar media was developed. The thiofuranosides are useful as precursors for carbohydrate synthesis, biological active molecules, and bio-surfactants. Dodecylbenzenesulfonic acid (DBSA), a commercially available Brønsted acid-surfactant, was employed to increase solubility of substrates and enhance rate of the glycosylation. Herein, we report the dehydrative glycosylation of furanosides and pyranosides with aliphatic, aromatic, and heterocyclic thiols in aqueous media to afford the thiofuranosides. Microwave irradiation led to improved yields and shorter reaction times. Other reaction parameters such as temperature and the amount of acid used were also optimized. Aliphatic and aromatic thiofuranosides were …

Go to article

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 …

Go to article

Synthesis And Development Of Dipicolylamine Derivatives As New Fluorescent Chemosensors, Waroton Paisuwan Jan 2017

Synthesis And Development Of Dipicolylamine Derivatives As New Fluorescent Chemosensors, Waroton Paisuwan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Di-2-picolylamine (DPA) is a powerful chelator for many transition metal ions. In this thesis, new DPA fluorescent chemosensors consisting of a fluorophore such as either naphthalimide or quinoline are developed. The first part deals with the synthesis of 1,8-naphthalimide derivatives linked 2-, 3-, 4-((bis(pyridin-2-ylmethyl)amino)methyl)aniline, and 4-amino-2-((bis(pyridin-2-ylmethyl)amino)methyl)phenol. The metal ion sensing experiments showed N3D was selective toward Ag+ with fluorescent enhancement in aqueous emitting green fluorescence under blacklight. The complexation of [N3D+Ag+] is a 1:1 stoichiometric binding with a limit of detection (LOD) 0.67 µM. Second part is the synthesis of oxazolidinonyl DPA derivatives by using self-developed halo-induced cyclization followed by …

Go to article

Metabolic Responses Of Aspergillus Niger Es4 To Ethanol Stress, Wimonsiri Kongchai Jan 2017

Metabolic Responses Of Aspergillus Niger Es4 To Ethanol Stress, Wimonsiri Kongchai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Aspergillus niger ES4 is a fungus isolated from the top wall of an ethanol tank of the PTT public company limited. Because normally, microorganism cannot tolerate high amount of ethanol, the growth of A. niger ES4 on the ethanol tank indicates the special properties of this fungal strain in response to ethanol. This research was therefore aimed at studying the effects of ethanol on the metabolites production of A. niger ES4 by using both untargeted and targeted metabolomics. When A. niger ES4 cultures were grown in minimal media containing 4% of ethanol for 3 days, A. niger ES4 responded to …

Go to article

Influence Of Crumbed Para Rubber Modifier In Aggregate Blend On Deformation Resistance Properties Of Hot Mix Asphalt, Hatthaphone Silimanotham Jan 2017

Influence Of Crumbed Para Rubber Modifier In Aggregate Blend On Deformation Resistance Properties Of Hot Mix Asphalt, Hatthaphone Silimanotham

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research presents the influence of crumbed para rubber which is added into a portion of aggregate in hot mix asphalt (HMA) during the batch mixing process or called "Dry Process". The dry process has an advantage on its simplicity of quality inspection and less modification in the hot mix plant production process. This study has investigated the effects of adding crumbed para rubber particles on the engineering properties related to permanent deformation resistance of asphalt concrete. In this study, the asphalt mixture is prepared via Marshall Mix design, which contained with limestone and asphalt cement of Pen 60/70 at …

Go to article

Multi-Layered Elastic Medium Under Axisymmetric Loading And Surface Energy Effects, Kanin Tarntira Jan 2017

Multi-Layered Elastic Medium Under Axisymmetric Loading And Surface Energy Effects, Kanin Tarntira

Chulalongkorn University Theses and Dissertations (Chula ETD)

Multi-layered nano-scale structures have been found in a wide range of applications these days. Since the surface energy effect is presented at the nano-scale level, a novel calculation scheme is required to accurately capture the mechanical behaviors of such structures. In this study, a solution scheme for analysis of a multi-layered elastic medium with influence of surface energy effects subjected to axisymmetric loading by adopting Gurtin-Murdoch surface elasticity theory is presented. The standard Love's representation and Hankel integral transform are employed to derive the general solutions, and the obtained solutions are employed in the determination of the stiffness matrix for …

Go to article

Factors Affecting Building Damage And People's Preparedness For Earthquake In Chiang Rai, Narongdej Intaratchaiyakit Jan 2017

Factors Affecting Building Damage And People's Preparedness For Earthquake In Chiang Rai, Narongdej Intaratchaiyakit

Chulalongkorn University Theses and Dissertations (Chula ETD)

On May 5, 2014, an earthquake with a magnitude of 6.3 on the Richter scale occurred in Chiang Rai, Thailand. This earthquake was the strongest earthquake in Thailand at the Mae Lao District region. It also caused building damage and casualties. In this research, 277 participants living in village no.2 and village no.7 of Dong Mada, a sub-district at Mae Lao district in Chiang Rai, were selected. A questionnaire was used to interview these participants, and the data were analyzed by Chi-square, Fisher's exact test, a Mann-Whitney U test, and a Kruskal-Wallis test. The objective of this study was to …

Go to article

Weakly Singular Boundary Integral Equation Method For Analysis Of Generalized T-Stresses Of Cracks In 3d Coupled-Field Media, Naruethep Sukulthanasorn Jan 2017

Weakly Singular Boundary Integral Equation Method For Analysis Of Generalized T-Stresses Of Cracks In 3d Coupled-Field Media, Naruethep Sukulthanasorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis presents the development of a weakly singular boundary integral equation method for the analysis of the generalized T-stress of isolated cracks embedded in a coupled-field whole space. A pair of weak-form integral equations, one for crack-face generalized traction and the other for the gradient of the crack-face generalized displacement, is established in a general framework allowing various types of materials including elastic, piezoelectric, piezomagnetic and piezoelectromagnetic solids, general crack geometry and loading conditions to be handled in a unified fashion. In addition, the final governing integral equations contain only weakly singular kernels and this, as a result, renders …

Go to article

First Prev Next Last