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2018

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Extraction Of Spent Green Tea Leaves As Bioactive-Compound Source, Monsichar Yannarat Jan 2018

Extraction Of Spent Green Tea Leaves As Bioactive-Compound Source, Monsichar Yannarat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Spent green tea leaves (SGTL) are a major contributor to the high cost of commercial tea products because of the large amount of leftover and the cost of disposal. This research investigates on the solvent and time for the extraction of SGTL that provides good yield of potential compound and to separate bioactive compounds as enrich-fractions and pure compounds. The obtained fractions were evaluated for antioxidant, antityrosinase, anticholinesterase and plant growth regulator activities. Caffeine was found in all samples. Among five extracts, the dichloromethane extract revealed high caffeine content (92.8 %peak area), while the methanol extract showed the highest five-catechin …

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Production Of 1, 12- Dodecanedioic Acid By Recombinant Microbial Cytochrome P450 In Pichia Pastoris And Saccharomyces Cerevisiae, Phawadee Buathong Jan 2018

Production Of 1, 12- Dodecanedioic Acid By Recombinant Microbial Cytochrome P450 In Pichia Pastoris And Saccharomyces Cerevisiae, Phawadee Buathong

Chulalongkorn University Theses and Dissertations (Chula ETD)

1,12-Dodecanedioic acid (DDA) is a primary compound which is used as an intermediate precursor for production of valuable chemical products. Biosynthesis of 1,12-DDA by recombinant (r) microorganisms can be used as an alternative method to compensate several disadvantages from chemical synthesis. The purpose of this study was to clone a CYP52A17 from Candida tropicalis to produce cytochrome P450 which can terminally oxidize fatty acids to hydroxy-fatty acids and further to dicarboxylic acids (ω-oxidation). The wild type rCYP52A17 and its engineered L261S/L490S (leucine changed to encode for serine) form (rCYP52A17mut) were expressed in Pichia pastoris and Saccharomyces cerevisiae which coexpressing the …

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Characterization Of Pmspӓtzle And Spipm5 From Black Tiger Shrimp Penaeus Monodon, Sittichai Boonrawd Jan 2018

Characterization Of Pmspӓtzle And Spipm5 From Black Tiger Shrimp Penaeus Monodon, Sittichai Boonrawd

Chulalongkorn University Theses and Dissertations (Chula ETD)

Humoral response proteins in shrimp, antimicrobial proteins (AMPs) and proteinase inhibitors, are implicated in host defenses against the pathogen infection because their expression is changed in response to microbial infection. After the pathogen infection in shrimp, the Spätzle protein is synthesized and activated the pathogenic signaling via Toll pathway by its active protein for the synthesis of AMPs. In this study, three PmSpätzle isoforms, PmSpz1, 2 and 3 genes, were identified in Penaeus monodon. The PmSpz1 gene was chosen for studied in details. Its gene was expressed in all shrimp tissues tested and in response to WSSV infection. Western blot …

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Optimization Of Protein Hydrolysate Preparation And Their Angiotensin I-Converting Enzyme Inhibitory Activity From Shiitake Mushrooms Lentinula Sp., Supawee Paisansak Jan 2018

Optimization Of Protein Hydrolysate Preparation And Their Angiotensin I-Converting Enzyme Inhibitory Activity From Shiitake Mushrooms Lentinula Sp., Supawee Paisansak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Angiotensin-I converting enzyme (ACE) is a key enzyme involved in regulating blood pressure. ACE converts angiotensin-I into angiotensin-II, which results in raised blood pressure. Inhibition of ACE leads to a decreased concentration of angiotensin-II and lowering of blood pressure. Food protein-derived ACE inhibitory peptides are considered to be a safer alternative to antihypertensive drugs. Shiitake mushrooms, one of the most consumed mushrooms in Thailand, are recognized as a nutritive food with health-stimulating properties. The aim of this study was to optimize the preparation of a shiitake-protein hydrolysate and investigate the ACE inhibitory activity of the hydrosylate. Shiitake mushrooms were hydrolyzed …

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Production And Characterization Of Cutinase From Tropical Fungi And Application With Detergent For Stain And Fuzz Removal From Spun Polyester Fabrics, Taweeporn Sooksai Jan 2018

Production And Characterization Of Cutinase From Tropical Fungi And Application With Detergent For Stain And Fuzz Removal From Spun Polyester Fabrics, Taweeporn Sooksai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Fungi were isolated from agricultural soil and plant specimens. Twenty three isolates from 44 fungal isolates were found to produce cutinase by using PCL-plate clearing assay and their cutinase activity were investigated. All the cutinase-producing fungi were cultured in liquid mineral medium (LMM) containing PCL or crude cutin extracted from papaya peels, which was a carbon source for cutinase production. Cutinase activity was assayed base on the hydrolysis of paranitrophenyl butarate (p-NPB). It was found that PBURU-T5 gave the highest cutinase activity. The isolate PBURU-T5 was selected for identification based on morphology together with comparative nucleotide sequencing from internal transcribed …

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Glycation And Α-Glucosidase Inhibitors From Boesenbergia Rotunda And Lansium Parasiticum, Thammatee Potipiranun Jan 2018

Glycation And Α-Glucosidase Inhibitors From Boesenbergia Rotunda And Lansium Parasiticum, Thammatee Potipiranun

Chulalongkorn University Theses and Dissertations (Chula ETD)

Glycation is spontaneous non-enzymatic reaction between protein and glycation precursors; methylglyoxal (MG) that initially yields advanced glycation end-products (AGEs), which ultimately trigger to several severe complications. Therefore, the inhibition of AGEs formation is the imperative approach for alleviating diabetic complications. Moreover, one of typical diabetic therapy is α-glucosidase inhibition to reduce glucose level in bloodstream. Therefore, this research aims to study bioactivity and mechanism of natural products to inhibit glycation and α-glucosidase. From preliminary study of some phenolic compounds, flavanones from fingerroot (Boesenbergia rotunda) could inhibit glycation. The dichloromethane extract of fingerroot afforded three flavanones (pinocembrin, pinostrobin, and alpinetin), two …

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Flowering Phenology And Pollination Biology Of Ceropegia Thailandica Meve And Ceropegia Suddeei Kidyoo, Chayanin Kraithep Jan 2018

Flowering Phenology And Pollination Biology Of Ceropegia Thailandica Meve And Ceropegia Suddeei Kidyoo, Chayanin Kraithep

Chulalongkorn University Theses and Dissertations (Chula ETD)

The flowers of the genus Ceropegia have complex structures that involve in pollination mechanism. These structres gynostegium, pollinarium and corona. Moreover, the corolla tube which is inflated at base and the corolla lobes are connate only at tip forming a cage-like structure functions as a trap. When pollinators are attracted to flower, they could be temporarily trapped inside the flower. From previous studies, there are about 18 species in Thailand. Most Thai species have flowers characterized by a long narrow corolla lobe with distinct inflated basal portion. However, some species have a short corolla tube, such as C. thailandica Meve. …

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Taxonomic Revision And Pollination Biology Of Orchid Genera Crepidium Blume And Dienia Lindl. (Malaxidinae, Orchidaceae) In Thailand, Anchalee Nuammee Jan 2018

Taxonomic Revision And Pollination Biology Of Orchid Genera Crepidium Blume And Dienia Lindl. (Malaxidinae, Orchidaceae) In Thailand, Anchalee Nuammee

Chulalongkorn University Theses and Dissertations (Chula ETD)

The terrestrial orchid Crepidium Blume and Dienia Lindl. in Thailand were enumerated by Gunnar Seidenfaden under Malaxis with key and drawings. Because of no species descriptions in publication, it is difficult to delimit species boundary. Moreover, recent discovery of new species results in unreliable assessment of species, therefore, the taxonomic revision of Crepidium and Dienia in Thailand should be carried out. The results indicated that the column and transversal callus on labellum are taxonomically important characters to delimit these two genera. In addition, morphological characters, i.e. stem and leaf morphology, labellum auricles, margins and number of teeth on distal margin …

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Taxonomic Revision Of The Fern Family Athyriaceae In Thailand, Puttamon Pongkai Jan 2018

Taxonomic Revision Of The Fern Family Athyriaceae In Thailand, Puttamon Pongkai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The most up-to-date account of the Athyriaceae is in Flora of Thailand. This account includes seven genera, i.e. Athyrium, Anisocampium, Cornopteris, Deparia, Diplazium, Hypodematium and Kuniwatsukia. Previously, the taxonomic relationships among genera were ambiguous and not well understood. The existing keys and descriptions are uncertain and do not include some unknown taxa. This research aims to clarify the taxonomic status of this family and its genera based on morphological, anatomical, palynological and molecular data. The results indicated that the types and shapes of frond, scale types, sorus shapes, shapes of vascular bundle and ornamentation of spores are valuable characters for …

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Simulation Of Water Effect On Biodiesel Production Using Waste Cooking Oil Via Ester-Transesterification In A Reactive Distillation Column, Ajala Anantapinitwatna Jan 2018

Simulation Of Water Effect On Biodiesel Production Using Waste Cooking Oil Via Ester-Transesterification In A Reactive Distillation Column, Ajala Anantapinitwatna

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the effect of water content in waste cooking oil (WCO) on the performance of a reactive distillation column for biodiesel production via ester-transesterification. A mixture of triolein and oleic acid was used as a WCO model compound. Amberlyst-15 was used to catalyze esterification while CaO was used for transesterification. From Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model taking into account water absorption for esterification of oleic acid (FFA), biodiesel yield was decreased with increasing of water content in WCO feedstocks. On the other hand, the initial rate of transesterification was increased with increase of amount of water in WCO feedstocks …

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Synthesis Of Activated Carbons From Coffee Ground Residues And Their Application As Catalysts For Ethanol Dehydrogenation, Jeerati Ob-Eye Jan 2018

Synthesis Of Activated Carbons From Coffee Ground Residues And Their Application As Catalysts For Ethanol Dehydrogenation, Jeerati Ob-Eye

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this present study, characteristics and catalytic properties of activated carbon derived from coffee ground residue, cobalt metal (Co) supported-activated carbon and various metals (Ce, Co, Cu and Ni) supported-commercial activated carbon were determined and characterized. This study was divided into three parts. Regarding to the first part, the synthesis of activated carbon catalysts derived from coffee ground residues with different methods of physical activation was investigated. The results showed that the catalyst with physically activated by CO2 for 4 hours, exhibited the best catalytic activity of ethanol dehydrogenation to acetaldehyde. In the second part, the best catalyst from the …

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Hydrothermal Carbonization Carbon-Based Acid Catalyst For Biodiesel Production, Laddawan Tumkot Jan 2018

Hydrothermal Carbonization Carbon-Based Acid Catalyst For Biodiesel Production, Laddawan Tumkot

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aims to synthesize the production of biodiesel (oleic acid methyl ester) by esterification in the presence of sulfonated hydrothermal carbon based catalyst under microwave irradiation. The catalyst was prepared by hydrothermal carbonization, followed by sulfonation presenting sulfonic acid group as an active site. The catalyst characterization results confirmed good microwave-absorptivity of the catalyst which can be heated directly and accelerate the reaction immediately at the surface of the catalyst. Esterification of oleic acid (OA) with methanol experiments were optimized by using response surface methodology based on central composite design. Three variables: molar ratio of methanol to OA (2.5:1-7.5:1), …

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Effect Of Cu Modified Tio2 Catalysts Prepared By Incipient Wetness Impregnation And Sputtering For Photocatalytic Co2 Reduction In Aqueous Solution, Nantiya Jantarasorn Jan 2018

Effect Of Cu Modified Tio2 Catalysts Prepared By Incipient Wetness Impregnation And Sputtering For Photocatalytic Co2 Reduction In Aqueous Solution, Nantiya Jantarasorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, we investigated the photocatalytic CO2 reduction in aqueous solution and were carried out in a stirred slurry reactor using Cu/TiO2 catalysts synthesized by incipient wetness impregnation and sputtering method. Effects of Cu loading onto titania support enhancing efficiency of the photocatalytic CO2 reduction in aqueous solution under UV irradiation by a band gap energy modification appeared between valence band and conduction band are narrowed. Cu assisted a selective hydrocarbon compound, this is methane. A comparison between Cu/TiO2 catalysts synthesized by incipient wetness impregnation and sputtering method showed that both methods exhibited similar methane selectivity. Sputtered catalysts are …

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Electrode Improvement Using Diamond-Like Carbon For Electrochemical Advanced Oxidation In Diuron Degradation, Nimit Kantiyawong Jan 2018

Electrode Improvement Using Diamond-Like Carbon For Electrochemical Advanced Oxidation In Diuron Degradation, Nimit Kantiyawong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Diuron is one of the pesticides. Its residual can contaminate natural water resource resulting in environmental and human health problems. Several processes have been used to remove diuron contamination. Nowadays, an electrochemical advanced oxidation process (EAOP) in a microchannel reactor is used to degrade diuron owing to its high efficiency. In this research, the diamond-like carbon (DLC) thin film was used as an electrochemical electrode because it has superior hardness and electrical conductivity. In this research, we have successfully synthesized the DLC thin films using graphite as target material on the surface of 304 stainless steel substrate by the direct …

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Synthesis Of Black Titanium Dioxide And Effect Of Calcination Conditions And Reducing Agent On Photocatalytic Degradation Of Methyl Orange, Saran Saensook Jan 2018

Synthesis Of Black Titanium Dioxide And Effect Of Calcination Conditions And Reducing Agent On Photocatalytic Degradation Of Methyl Orange, Saran Saensook

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research studied the synthesis and application of black titanium dioxide in the photocatalytic degradation of methyl orange (MO). First, titanium dioxide was prepared via a sol-gel method. Then sodium borohydride was used as the reducing agent in order to synthesize black titanium dioxide. Thus, a 2x2x3 factorial experimental design was employed to assess the significance of the following three factors: (A) calcination temperature (400 and 500 °C); (B) calcination time (5 and 10 h); and (C) the molar ratio of NaBH4 to TiO2 used (0:1, 0.5:1, and 1:1). The removal of MO under UV and visible light were the …

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Application Of Amine-Functionalized Titanium Dioxide Wrapped In Reduced Graphene Oxide In Photocatalytic Degradation Of Methylene Blue, Sirinya Kanjanapanasont Jan 2018

Application Of Amine-Functionalized Titanium Dioxide Wrapped In Reduced Graphene Oxide In Photocatalytic Degradation Of Methylene Blue, Sirinya Kanjanapanasont

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the effect of reduced graphene oxide (rGO) addition to amine-functionalized titanium dioxide (APTMS-TiO2). The loading amount of rGO was varied from 0 to 0.05 %wt. Also, the effect of the amount of 3-aminopropyltrimethoxysilane (APTMS) was studied. To synthesize TiO2/rGO catalysts, the amount of APTMS was varied at 2.21 and 22.1 mmol. TiO2 catalyst was synthesized via a sol-gel method. Next, the surface of TiO2 was modified with APTMS by refluxing. Then graphene oxide was wrapped around APTMS-TiO2 and was reduced to rGO using hydrazine and ammonia. In the experiment, the catalyst was dispersed in methylene blue solution …

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Improving The Efficiency Of Dye-Sensitized Solar Cells With Ultrasonic Spray-Coated Tio2 Electrode That Was Modified By Mno2, Coo, Or Sno2, Supasun Thanadvanichkul Jan 2018

Improving The Efficiency Of Dye-Sensitized Solar Cells With Ultrasonic Spray-Coated Tio2 Electrode That Was Modified By Mno2, Coo, Or Sno2, Supasun Thanadvanichkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the modification of TiO2 electrode by adding the second metal oxide, namely, manganese dioxide (MnO2), cobalt oxide (CoO), or tin dioxide (SnO2) use in for dye-sensitized solar cell (DSSCs). TiO2 and modified TiO2 sols were synthesized via sol-gel methods. The sols were sprayed 500 times onto the fluorine-doped tin oxide glass substrates as a thin film using an ultrasonic spray coater. Finally, the thin film electrode was calcined at 400ºC for two hours. The amount of MnO2, CoO, or SnO2 was varied at 0, 0.1, 0.5, 1.0, and 3.0%wt. The photovoltaic efficiency of DSSCs was measured using …

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Lactic Acid Production From Glucose By Using Divalent Transition Metal Oxide Catalyst On Magnesium Oxide Support Without Alkaline Solution, Tanyatorn Udomcharoensab Jan 2018

Lactic Acid Production From Glucose By Using Divalent Transition Metal Oxide Catalyst On Magnesium Oxide Support Without Alkaline Solution, Tanyatorn Udomcharoensab

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research was studied the effects of the type of divalent metal oxide (Cu, Co, Ni, and Zn) supported on magnesium oxide catalyst using the hexadecyltrimethylammonium bromide (CTAB) as the capping agent with metal loading at 1.5, 5, and 10 mmol/gram-catalyst on lactic acid production from glucose. To achieve the lactic acid production of lower reactor corrosion rate and being environmentally friendly, the reaction was performed in an alkali additive-free environment. The catalysts were synthesized by hydrothermal method and characterized by various techniques. The XRD pattern of spent CuCTAB/MgO and CoCTAB/MgO catalyst showed the reduced metal species indicated the used …

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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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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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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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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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