cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2016.196
title: Highly dispersed graphene oxide-silver nanoparticle composites in organic solvents

description: An innovative phase transfer process of anisotropic silver nanoparticles (AgNPs) from water to a wide range of organic solvents such as toluene, n-butanol, iso-butyl acetate, ethyl acetate, acetonitrile and ethylene glycol was described. In the developed process, AgNPs were transferred to the organic solvents by using the graphene oxide (GO) sheets as the carrier. The transferring process was utilized by two straightforward steps. Firstly, AgNPs were synthesized using N-N' dimethylformamide (DMF) as a reducing agent and they were stabilized by the numerous of oxygen-functional groups on the GO surface via electrostatic interaction to form GO/AgNP composites. The existence, purity and stability of AgNPs on the GO sheets were examined and analyzed by several techniques such as UV-Visible spectroscopy (UV-Vis), Fourier-transform Infrared (FT-IR) spectroscopy, Raman spectroscopy, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Secondly, the GO/AgNP composites were modified with oleylamine (OAm) in order to improve hydrophobicity. To obtain the maximum phase transfer efficiency, an appropriate amount of OAm was carefully optimized for each organic solvent. The dispersion behavior of the GO/AgNP composites modified with OAm (GO/AgNP-OAm) in the organic solvents were investigated. It was found that the GO/AgNP-OAm are uniformly dispersed in the organic solvents for at least 6 hours after sonication. The developed phase transfer method has the features of simplicity and high efficiency.
DOI: 10.14457/cu.the.2016.197
title: Highly selective fluorescence sensors for biogenic amines and copper (II) ion

description: This research aims to design and synthesize the molecular sensors for biogenic amine sensing and fabricate 3D microfluidic device. In the case of biogenic amine, it can be classified into two group, the first group is catecholamine and the second group is histamine and histidine. For catecholamine sensing, coumarin aldehyde (CA) and pyrene boronic acid (PBA) formed intermolecular assembly in the presence of neurotransmitters and induced FRET on process from PBA to CA. The result showed DA and NE performed a guest linker including intermolecular assembly of CA and PBA resulting in FRET on/off process. In the case of histidine and histamine sensing, we designed histamine sensor, consisting of histamine blue (HB) loaded in nanoporous silica modified surface by fluorescein isothiocyanate (FC). The result showed that histamine induced an increasing fluorescent intensity at 525 nm (ex. 340 nm) by energy transfer process from HB to FC. No fluorescence response was observed in the case of histidine due to the electronic repulsion between negative charge on carboxylate based fluorescein dye on the surface and carboxylate group in histidine. In the case of 3D microfluidic device, we developed the quantitative assay by fabrication of FBA and fluorescein dye on the paper. This research designed the device into two part of assay zone and control zone for normalization the factor of flow-through rate of the sample. This device provided the linear range from 10-100 micro molar of copper ions concentration and it was applied to measure Cu2+ ion in blood sample with an acceptable value of 103.38% recovery.
DOI: 10.14457/cu.the.2016.198
title: Effects of CuIn1-xGaxSe2 thin film surface roughness in chemical bath deposition of CdS thin films

description: Typical CuIn1-xGaxSe2 (CIGS) thin film solar cells on soda-lime glass (SLG) substrate consist of six different thin film layers; SLG/Mo/CIGS/CdS/i-ZnO/ZnO(Al)/Al-grids. In this work, the interface of CIGS/CdS film was modified by altering CIGS surface with various chemical solutions such as aqua regia, potassium hydroxide and alcoholic potassium hydroxide. The modified CIGS surface was investigated by FESEM and AFM in terms of morphology and RMS roughness, respectively. It was found that aqua regia could effectively alter the CIGS surface while the others could not visually change the surface. The J-V and external quantum efficiency (EQE) measurements showed that potassium hydroxide and alcoholic potassium hydroxide etchings resulted in lower solar cell performance than aqua regia etching when compared with the non-etched condition. The concentration and etching time using aqua regia were investigated. As a result, using 1:1 of aqua regia : deionized water at a few seconds of etching time could create an optimal CIGS surface roughness for the CIGS/CdS interface. This method was employed in the fabrication of the CIGS solar cells in order to improve its performance.
DOI: 10.14457/cu.the.2016.199
title: Fabrication of PDMS lenses with precisely controlled curvatures by confined sessile drop technique

description: This research presented a novel approach for forming lens form elastomeric polydimethylsiloxane (ePDMS) with precisely controlled properties such as curvature, focal length, and magnification via the confined sessile drop technique. This technique is simple, rapid, and cost effective for mass-scale production. The ePDMS lens with plano-convex shape can be directly attached onto a smartphone camera and transform into portable smartphone digital microscope. The fabrication procedure of ePDMS plano-convex lens involved an injection of liquid PDMS (lPDMS) 3-100 µL onto a circular disk with the diameter in the range 2-10 mm. The resistances to spreading by sharp enabled the reproducibility of spherical cap of lPDMS. The lPDMS axisymmetrically spread under the balance between the gravitational force and interfacial tension force for precisely controlled spherical cap. A thermal treatment at 80 oC for 30 min cured the spherical caps lPDMS into a bubble-free solid ePDMS plano-convex lens. The ePDMS plano-convex lens with focal lengths of 3.4-55.2 mm and magnifications of 4.5X-73.5X could be repeatedly reproduced. Portable smartphone digital microscope can be used to capture small objects that cannot be seen with the naked eye such as micro-printing, and gun shoot residue. High-resolution panorama microscope images without distortion were also demonstrated.
DOI: 10.14457/cu.the.2016.200
title: Selective oxidation of saturated hydrocarbons catalyzed by oxovanadium(iv) complexes

description: The development of the selective oxidation of saturated hydrocarbons catalyzed by oxovanadium(IV) complexes was disclosed. Two types of ligands including Schiff’s base and picolinic acid could be prepared. The well-characterized oxovanadium(IV) complexes were applied under two diverse oxidizing agents: O2 and peroxide. The oxidation catalyzed by oxovanadium(IV) Schiff’s base complexes in zinc-pyridine-acetic acid system under O2 was thoroughly investigated for the effects of nine Schiff’s base complexes, amount and type of zinc, acid and solvent. VO(salophen) exhibited good activity in terms of yield of desired product(s) and selectivity. Utilizing this catalyst in combination with TBHP at reflux or H2O2 at room temperature in CH3CN could promote the selective oxidation reaction. These three catalytic systems revealed the unique characteristics for ketone formation as a major product together with small amount of accompanying alcohol. Employing VO(pic)2 in TBHP system, saturated hydrocarbons were oxidized faster than using VO(salophen) and still provided ketone as predominant product in good yield. The addition of hexabromoacetone (HBA) converted the activation process to furnish alkyl bromide efficiently instead of oxidized products. Chemoselectivity study implied the clues that reaction mechanisms of two systems were different. Non-radical pathway was operated in zinc-pyridine-acetic acid-O2 system while for peroxide system, the oxidation proceeded via radical process.
DOI: 10.14457/cu.the.2016.201
title: Synthesis of glutathione-/lipoic acid-porphyrin compounds as novel biocompatible antioxidants

description: A novel water-soluble porphyrin derivative bearing lipoic acid and manganese complex of this compound were successfully synthesized based primarily on the amidation reaction. The desired products, P-4Lp and Mn-P-4Lp, were achieved in the overall yields of 5% and 4% respectively from commercially available starting material. All new compounds were characterized by NMR spectroscopy and mass spectrometry. Their optical properties were also investigated by UV-visible and fluorescence spectrophotometry. According to cell cytotoxicity test, IC50 of P-4Lp and Mn-P-4Lp were found in the range of 50 to 100 mg/L and more than 150 mg/L against HaCaT and HDFa cells, respectively. Thus, both products were considered to be low cytotoxicity compounds. However, based on the antioxidant activity test, no antioxidizing activity of these compounds in both kinds of cells was observed. In addition, mitochondria targeting evaluation suggested that the target porphyrin derivatives exhibited accumulation specifically in the mitochondria of the HaCaT cells.
DOI: 10.14457/cu.the.2016.202
title: Fischer-Tropsch synthesis over cobalt supported on silica hollow sphere catalyst

description: A propose of this work studied the silica hollow sphere (SHS) for a proper characteristic of support in the Fischer-Tropsch synthesis (FTS) because the normally main problem of FTS reaction was being produced the broader hydrocarbon products on a commercial catalyst. Nevertheless, the hollow sphere shape of SHS catalyst had a wall of the core catalyst for steric restriction of hydrocarbon propagation. The cobalt metals were loaded on the SHS by wetness impregnation method and used in the FTS. The SHS was synthesized through emulsion process with water/oil/water (W/O/W) that used the sodium silicate for silica source and NH4HCO3 for the mesopore generating in the SHS support. The proper SHS catalyst in FTS showed higher specific surface area more than 500 m2/g and less micropore, causing diffusion elimination and mass transfer inside the pore, which resulted in the enhanced CO conversion more than 90 percent, lower C12+, and the narrower hydrocarbon selectivity. Moreover, the study of the coated zeolite that was ZSM-5 type on the SHS catalyst was two methods, which were hydrothermal synthesis and steam-assisted crystallization (SAC) process. The results of both methods represented the increase of narrower hydrocarbon products, isoparaffins and olefins selectivity due to acid sites of the zeolite. However, these methods as the improved cobalt based over SHS catalyst had some problems such as the decomposing of the silica, removing of cobalt metals on the SHS support and uncovering of some zeolite over the SHS catalysts.
DOI: 10.14457/cu.the.2016.203
title: Molecular characterization of isoamylases from cassava tuber Manihot esculenta Crantz ‘KU50’

description: Starch debranching enzyme or isoamylase (EC.3.2.1.68), an important enzyme in starch metabolism, catalyses the hydrolysis of α-1,6 glycosidic linkages of amylopectin. In this work, cassava isoamylase genes were isolated from cDNA generated from total RNA from tubers of Manihot esculanta Crantz cultivar KU50 by RT-PCR and analysed by agarose gel electrophoresis. Three putative isoamylase genes, MeISA1, MeISA2 and MeISA3 were identified and amplified excluding the fragments encoding their transit peptides. Full length of MeISA3 gene was obtained by 5’ Rapid Amplification of cDNA Ends (5’ RACE). The mature MeISA1 and MeISA2 were successfully amplified and cloned into a pETDuet1 vector, while the mature MeISA3 was amplified and cloned into a pET21b and sequenced. The ORFs of mature recombinant MeISA1, MeISA2 and MeISA3 genes were 2,292, 2,649 and 2,127 kb, encoding 763, 882 and 708 amino acid with substantial similarity to StISA1, StISA2 and StISA3 from potato at 84.4%, 68.9% and 80.9%, respectively. Then, rMeISA1 and rMeISA2 were coexpressed and rMeISA3 was single expressed in Escherichia coli SoluBL21(DE3) and purified by HistrapTM column. Analysis by SDS-PAGE and immunoblot showed approximate molecular weights of 87, 99, and 80 kDa, respectively. Debranching activity was only detectable in the fractions where both rMeISA1 and rMeISA2 were present. The heteromultimeric DBE from 4-5 h induced culture analysed by gel filtration chromatography and Western blot showed combinations of rMeISA1 and rMeISA2 at ratios of 1:1 to 1:4. Pooled fractions of rMeISA1/rMeISA2 with DBE activity and the purified rMeISA3 were used for enzyme characterisation. Both rMeISA1/rMeISA2 and rMeISA3 showed the optimum activity at 37ºC but their optimum pH were at 7.0 and 6.0, respectively. Enzyme activity of rMeISA1/rMeISA2 was enhanced by Co2+, Mg2+ and Ca2+, whereas rMeISA3 activity could be significantly activated by Mn2+ and Co2+. Cu2+ was a strong inhibitor for both enzymes. Debranched amylopectin products analysed by HPACE-PAD showed chain length distributions typical of plant debranching enzymes with DP from 6 to 20 with major products around DP 10 to 12. rMeISA1/rMeISA2 were specific for amylopectin while rMeISA3 showed the highest activity on beta-limit dextrin. However, they could hardly hydrolyse pullulan at all, indicating their classification as isoamylase-type debranching enzyme. The debranching activity of rMeISA1 and rMeISA2 required their association as heteromeric complexes.
DOI: 10.14457/cu.the.2016.204
title: Enzymatic and computational analysis of large-ring cyclodextrin production by Corynebacterium glutamicum amylomaltase

description: Amylomaltase is a well-known glucanotransferase enzyme that can produce large-ring cyclodextrins (LR-CDs) via cyclization reaction. To determine important amino acid residues involved in LR-CDs production of amylomaltase from Corynebacterium glutamicum (CgAM), mutations at CA I and CA II subdomains were introduced by site-directed mutagenesis. P228Y, E231Y, A413F and G417F CgAM mutants were constructed from CgAM recombinant plasmid. The optimum pH and temperature of WT and mutants were around pH 6.0 - 7.5 and 25 - 35°C. The mutations did not affect the pH and temperature stability. In addition, WT and all mutated enzymes have Maltotriose (G3) as the best substrate for disproportionation activity. A413F possessed much lower specific activities of transglycosylation, starch degradation, disproportionation and cyclization activities than the WT enzyme. P228Y, E231Y and G417F exhibited similar specific activities of starch transglycosylation and starch degradation to the wild-type CgAM. P228Y had much lower disproportionation activity than the wild-type enzyme, while E231Y displayed higher disproportionation activity. This suggested that P228 and E231 of CgAM may play an important role in disproportionation. At 12 h, wild-type CgAM gave the principle CD of 27, whilst the principal product of P228Y, E231Y, A413F and G417F were CD36, CD25, CD38, and CD32, respectively. Molecular dynamic (MD) simulation showed that Y418, M474, L510, F534, Y23, R458, Q423, T666, Q475, L236, Q421, E231, Q420, N419 and Y235 might interact with LR-CDs.
DOI: 10.14457/cu.the.2016.205
title: Functional characterization of hemocyte homeostasis associated protein, HHAP in two species of crustaceans

description: Hemocyte homeostasis-associated protein (PmHHAP) has been reported as a viral responsive protein that plays an important role in controlling hemocyte homeostasis in shrimp Penaeus monodon. In this study, the role of PmHHAP in regulating apoptosis in shrimp was investigated. In vivo gene silencing of PmHHAP could induce the high level of apoptosis in shrimp hemocytes and altered the expression of apoptosis-related genes particularly PmCasp and PmCaspase. Moreover, PmHHAP was able to bind to PmCasp and the rPmHHAP protein could decrease apoptosis in the rPmCasp-treated hemocytes cells. These results indicated that PmHHAP is an anti-apoptosis protein that regulates hemocyte homeostasis by inhibiting apoptosis in P.monodon. Yeast two-hybrid and co-immunoprecipitation revealed that PmHHAP binds to an anti-apoptosis protein of white spot syndrome virus, WSSV134. The viral protein WSSV134 is a late protein of WSSV which is initially expressed after 24-hour post infection (hpi) and is likely involved in viral propagation. Co-silencing of PmHHAP and WSSV134 prior to WSSV infection showed significant increase of caspase activity, which was higher than silencing only PmHHAP or WSSV134, suggesting that these two proteins might work concordantly to control apoptosis during WSSV infection. Suppression subtractive hybridization (SSH) of PmHHAP silenced shrimp hemocytes identified several viral responsive genes as well as hemocyte homeostasis-related genes such as the transcription factor ATF-β, cathepsin L, lactate dehydrogenase, ferritin and inhibitor of apoptosis (IAP), some of which should be selected for further investigation. In addition, a homolog of HHAP in crayfish Pacifastacus leniusculus with 47% similarity to PmHHAP was functional characterized. PlHHAP was detected in all examined tissues but highly expressed in intestine and gill. Surprisingly, PlHHAP was found to play important role in bacterial but not viral defense in contrast to PmHHAP. PlHHAP transcript remained unchanged upon WSSV infection but dramatically increased upon bacterial Aeromonas hydrophila B1 challenge. Furthermore, suppression of PlHHAP resulted in increasing the number of bacteria in intestine but did not affected hemocyte apoptosis or the expression of genes (CHF, astakine1, astakine2, and IGFBP7) involved in crayfish hematopoiesis and hemocyte homeostasis suggested that HHAP from different crustacean species have different functions in defense against invading pathogens.
DOI: 10.14457/cu.the.2016.206
title: Two-phase fermentation for itaconic acid production by Aspergillus terreus NRRL1960 and its enzymatic and transcriptomic analyses

description: Typical itaconic acid fermentation usually suffers from low product concentration and yield due to a failure to balance the metabolic flux towards itaconic acid production. In this study, two approaches were employed to better understand the root causes mentioned above and to enhance itaconic acid production. In the first approach, ATP regeneration was manipulated during itaconic acid production by using L-aspartate. The presence of 10 mM L-aspartate in the production medium repressed the pyruvate carboxylase activity. This resulted in the limited malate flux in the cytosol and the large pool of pyruvate in the mitochondria. A. terreus stimulated the conversion of the large pool of cis-aconitate into itaconic acid via the antiporters. Successively, itaconic acid production yield and final concentration were improved from the control by 8.33 % and 60.32 %, respectively. In the second approach, the 2-phase fermentation process was employed. Itaconic acid was first observed when ammonium and phosphate became limited. Contrary to those claimed in 1-phase fermentation, by this technique, low DO level enhanced itaconic acid production because it promoted the correct morphology in the form of mycelial clumps. Also, low DO level initiated the uncouple glycolysis and oxidative phosphorylation, which stimulated substrate level phosphorylation for ATP regeneration. The available pyruvate was then reacted with coenzyme A by pyruvate-formate lyase, resulting in formate and acetyl CoA which induced the metabolite flux to produce itaconic acid.
DOI: 10.14457/cu.the.2016.207
title: Adsorption and conversion of small gases on TiO2 nanoparticles and surfaces of modified TiO2

description: Adsorptions of small gases and their reactions on modified anatase TiO2 (001) as ZnOSL supported on anatase TiO2 (001), (ZnOSL/TiO2), and Mn–doped TiO2 (001) surfaces have been studied by density functional theory (DFT) method. The calculation models relied on both of clusters and periodic boundary conditions (PBCs). It was found that Ti5C and O2c sites on anatase TiO2 (001) are active for ZnOSL supporting. The conversion of carbon monoxide by oxygen forming carbon dioxide gas over the ZnOSL/TiO2 composite was studied. Moreover, ZnOSL, transition metals, and non–metals doped–ZnOSL clusters have studied to understand the properties of their surfaces. Resulting from the study of small gases on the Sc–ZnOSL, the most stable adsorption configuration is SO2 adsorption. The most decreasing of energy gap for N2O bridge–structured adsorption on Sc–ZnOSL was found. The Sc–ZnOSL used as N2O or SO2 sensing material was suggested. For the system of Mn–doped anatase (001) surface, Mn–doped anatase (001) surface enhances the activity of O2 pre–adsorption and CO adsorption for CO to CO2 conversion. Therefore, the results indicate that modified anatase (001) surface can be used for the conversion of carbon monoxide by oxygen gas forming carbon dioxide gas reaction.
DOI: 10.14457/cu.the.2016.208
title: Transformation of organic compounds by transition metal salts in ionic liquids

description: A new, convenient, and high yielding synthetic protocol for transformation via oxidation process of various organic compounds using a combination of 1-hexyl-3-methylimidazolium bromide ([hmim]Br) and a transition metal salt, such as FeCl3, and CuCl2 is uncovered. The oxidation of alcohols utilizing FeCl3/[hmim]Br in the presence of tert-butyl hydroperoxide (TBHP) afforded the corresponding carbonyl compounds in high yields. Primary and secondary benzylic alcohols seem to be reactive substrates for conversion to the desired carboxylic acids and ketones, respectively, without by-products formed. For aromatization of cyclic dienes catalyzed by CuCl2 coupled with TBHP in [hmim]Br, cyclic hydrocarbons yielded highly amount of the expected aromatic substances under short reaction time, while heterocyclic amines furnished the expected heteroaromatics in moderate yield. Consequently, the developed catalytic system of a transition metal salt/[hmim]Br displayed the reusability in this methodology. For the dehydrogenation of N-heterocycles, FeCl2/DMSO combination under oxygen atmosphere offered the corresponding N-heteroaromatic products in good yields via radical involving process, the catalytic system operated better under conventional organic solvents than ionic liquids.