cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2015.388
title: Antifeedant activity against common cutworm Spodoptera litura Fab. from some Thai plants

description: Six essential oils and thirty-four plant extracts were preliminary screened for antifeedant activity against Spodoptera litura. The dichloromethane extract of Xylocarpus granatum, the essential oils from Ocimum basilicum, Hedychium coronarium and Daucus carota showed high antifeedant activity at 0.25% (w/w) with EC50 0.06, 0.12, 0.13 and 0.15% (w/w), respectively. The compositions of three essential oils were analyzed by GC-MS. Certain constituents were tested for antifeedant activity. Eucalyptol revealed the highest activity with EC50 0.8 mM. The dichloromethane extract of X. granatum was separated using bioassay-guided approach to search for antifeedant compound. Xyloccensin K, the major component exhibited antifeedant activity with EC50 1.3 mM. In addition, the UV light and temperature influence on the dichloromethane extract, xyloccensin K, and commercial neem extract was comparatively examined. The antifeedant activity of neem extract was significantly decreased more than the dichloromethane extract and xyloccensin K. Moreover, two methods using for antifeedant activity: mixing treatment with artificial diet and leaf disk toxicity assay were compared. Three essential oils, the dichloromethane extract and their constituents were tested for antifeedant activity with kale leave. The similar trend of antifeedant activity was found with both methods. Three essential oils, the dichloromethane extract of X. granatum, eucalyptol and xyloccensin K could be developed as effective antifeedant compounds against insect pests.
DOI: 10.14457/cu.the.2015.389
title: Allelopathic potential of leftover materials from sunflower helianthus Annuus L.

description: The allelopathic effects of the extracts of sunflower (Helianthus annuus L.) were evaluated on seed germination and growth inhibition of Mimosa pigra L. Dried leaves, stems and roots of sunflower were separately extracted by different solvents. The inhibition activity using three concentrations of 1.0, 2.5 and 5.0 gE was compared. The CH3OH extract of the leaves inhibited seed germination and the growth of M. pigra. This extract was further evaluated on allelophatic effects of selected weeds and crops. At 1 gE, the extract showed selective inhibition on seed germination of weeds more than crops, but expressed as non-selective inhibition on shoot and root elongation of all tested plants. Further examinations on pot experiments as pre- and post-emergence weed controller were conducted. The use of dried leaves as pre-emergence, and that of the CH3OH extract of the leaves as pre- and post-emergence inhibited seed germination and growth of all weeds, but less than those observed in petri-dish experiments. To control barnyard grass in rice cropping as pre- and post-emergence weed controller, at 1 gE of pre-emergence this extract inhibited barnyard grass germination 33% with no effect on the rice germination and shoot elongation, while inhibited 29% of root elongation. For post-emergence at 1 gE, the extract could completely inhibit the barnyard grass population with no side-effect on the growth of rice seedlings. In addition, all crude extracts were evaluated on other biological activities including antifeedant activity against common cutworm, antibacterial activity against 6 bacteria and 2 fungi. The CH2Cl2 extract of the roots gave the highest inhibition to Rhizoctonia solani (79%). This extract also expressed as selective inhibition on shoot elongation of zinnia and rice by stimulating their root elongation. The chemical composition of this fraction was investigated. Five substances: demethylencecalin, demethoxyencecalin, mokko lactone, a mixture of stigmasta-4,22-dien-3-one and stigmast-4-en-3-one, and a mixture of stigmasterol and β-sitosterol were identified based on spectroscopic evidence.
DOI: 10.14457/cu.the.2015.390
title: Applications of hexabromoacetone for protection-deprotection of acetals and ketals and for bromination of alkanes and dicarbonyl compounds

description: Hexabromoacetone (HBA) has been discovered for over a hundred years, but only a few of its applications have been reported. The carbon-bromine bond is generally weak and could be cleaved by UV irradiation, generating radicals that could be used for activating various reactions. In this research, HBA was used as a catalyst for protection of glycerol with acetone to form solketal, protection of benzaldehyde with methanol, protection of a variety of aldehydes and ketones with 1,3-propanedithiol, deprotection of benzaldehyde dimethyl acetal and other acetals, and deoximation of various oximes. The protection and deprotection were very fast and in most cases provided very high yields of the desired products using very small amount of HBA. Tested by a radical trapping reagent, the reactions likely proceeded via radical intermediates. Additionally, HBA was utilized as a brominating agent for the bromination of adamantane and diethyl malonate at room temperature under UV irradiation. The bromination of adamantane provided good yield and excellent selectivity of 1-bromoadamantane, while diethyl malonate can be both mono- and dibrominated depending on the reaction time and amount of HBA. Approximately 4 out of 6 bromine atoms of HBA can be used for bromination.
DOI: 10.14457/cu.the.2015.392
title: EXPLORATION OF BIOACTIVE COMPOUNDS FOR DIABETES THERAPY FROM SELECTED EAST KALIMANTAN FLORA

description: In search of α-glucosidase inhibitors for the treatment of type 2 diabetes mellitus and its complications, we examined the inhibitory effect of selected plants collected from East Kalimantan, Indonesia which included Leucaena leucocephala, Swietenia macrcophylla, Pycnarrhena tumefacta, Luvunga eleutherandra, Crescentia cujete, Ceriops tagal and Horsfieldia macrobotrys. On the basis of ethnopharmacological knowledge together with biological and chemical screenings, selected plants were further investigated to afford active compounds. The methanol extract from leaves of Ceriops tagal yielded three compounds classified as pentacyclic triterpenoids named lupeol (1), betulone (2) and betulin (3). Of isolated compounds, 3 showed highest inhibition against yeast α-glucosidase with IC50 value of 18.87 μM followed by 1 and 2, respectively. The kinetic study of 1-3 showed noncompetitive inhibition against baker’s yeast α-glucosidase. In addition, the methanol extract from Horsfieldia macrobotrys seed coats was investigated using an α-glucosidase and antioxidant-guided isolation. Two arylalkanones named 1-(2,4,6-trihydroxyphenyl)-9-phenylnonan-1-one (4) and malabaricone A (5) together with a flavanone named 7-hydroxyflavanone (6) were isolated. Arylalkanone 4 was the most potent inhibitor against free radical and baker’s yeast α-glucosidase with IC50 value of 2.6 mM and 10.8 μM, respectively. Interestingly, the methyl ether analogues 4a and 5a, prepared by methylation of 4 and 5 with MeI/K2CO3, showed dramatic drop in inhibition. This observation indicated the critical role of hydroxy groups (-OH) in exerting radical scavenging and α-glucosidase inhibition. The kinetic study of 4 indicated that baker’s yeast α-glucosidase was mixed manner. Since promising bioactivity of isolated arylalkanones from seed coats of H. macrobotrys, we further investigated other parts of this plant. Bioassay-guided isolation of stem bark extract resulted in two new arylalkanones named horsfieldone A (7) and maingayone D (8) together with a new flavanone-C-glycoside named 8-C-β-D-glucopyranosylpinocembrin (9). Maingayone D (8) displayed significantly more potent inhibition than 7 against α-glucosidase and free radical. Kinetic study of 7 and 8 indicated their mixed inhibition against α-glucosidase. The results of this study showed that ethnopharmacological knowledge from Dayak people in East Kalimantan together with biological and chemical screenings provided a successful strategy to discover potent antidiabetic agents.
DOI: 10.14457/cu.the.2015.393
title: Preparation of anion selective membrane electrodes from Donnan failure phenomenon induced by copper(II) ion

description: The fabrication of anion selective electrode using mono- and dinuclear metal complexes based on calix[4]arene and anthracene with different number of side-arms and donor atoms were used as ionophores or ion-carriers. The polymeric membrane containing the ionophore L1 and potassium tetrakis(p-chlorophenyl)borate (KTpClPB) as a cation exchanger in the presence of metal ions as triggers showed the Donnan exclusion failure phenomenon. The ionophore L1 bound metal ions very tightly inducing the co-extraction of anions into the membrane and changed the permselectivity of the membrane to anions by the observation of negative EMF responses. However, the membranes containing L2 – L4 gave the positive EMF responses to most metal salts. The best perchlorate anion selective electrode was accomplished using ionophore L1 and 25 mol% of KTpClPB related to the ionophore incorporated in the o-NPOE plasticized PVC membrane preconditioned in CuCl2 with Nernstian slope of -55.80 ± 0.36 mV/decade, over the concentration range of 10-5 – 10-2 M and the limit of detection of 2.84 μM. In addition, the fabricated membrane electrode could be used in the pH range of 3 – 9 with great reversibility and successfully applied to determine the concentration of perchlorate in tap water with satisfactory results.
DOI: 10.14457/cu.the.2015.394
title: EPOXY/AMINO-MODIFIED SILICA/PERFLUOROOCTYL TRIETHOXYSILANE NANOCOMPOSITE FOR SELF-HEALING HYBRID COATING

description: Self-healing hybrid nanocomposite was successfully prepared from epoxy resin containing self-healing microcapsules and modified nano-silica as a reinforcement to enhance anticorrosion performance of epoxy coating. 3-Glycidoxypropyl-trimethoxysilane (GPTMS) and 3-aminopropyl-trimethoxysilane (APTES) were used to modify nano-silica surface in order to accomplish proper dispersion of nanoparticles in polymer matrix. Perfluorooctyl triethoxysilane (POT), Ethanolamine (ETA) and Diethanolamine (DEA) as self-healing agents were encapsulated by polymer shell and incorporated into the epoxy coating along with modified nano-silica to form anticorrosion barrier of organic and inorganic coating on a cold-rolled steel (CRS) substrate. The effect of epoxy curing agents, modified silica and self-healing loading on the anticorrosion properties were studied. The modified silica nanoparticles and the self-healing agents were characterized using Fourier transform infrared spectroscopy (FTIR). Optical microscope (OM) was used to observe the microstructure and dispersion of nanoparticles. Anticorrosion performance of the coated CRS specimens was investigated by Tafel plot, cyclic voltammetry (CV) and salt spray test. The epoxy/3wt%GMS/20wt%POT nanocomposite possessed the best corrosion performance (Icorr = 0.012 mA/cm2 and corrosion rate of 0.139 mm/year). Electrochemical results were in agreement with the morphological results obtained from optical microscopy and scanning electron microscopy (SEM)
DOI: 10.14457/cu.the.2015.395
title: Melamine fluorescent sensors from naphthalimide-cyanuric acid conjugates

description: The development of melamine sensors is an important research theme because contaminating melamine in dairy products or infant powder is toxic to human health, especially for babies. In this research, five novel fluorescent sensors (F1 to F5) containing a 1,8-naphthalimide fluorophore and cyanuric moiety as melamine receptor are designed and successfully synthesized. All target compounds are characterized by 1H and 13C-NMR, High Resolution Mass Spectrometry, and Elemental Analysis. The photophysical properties are investigated by UV-Vis and fluorescence spectroscopy. The selectivity screenings in aqueous DMSO indicate that F3, F4 and F5 give selective fluorogenic changes in the presence of melamine. The sensing mechanism involves the fluorophore aggregation and de-aggregation by multivalent hydrogen-bonding between melamine with cyanuric moiety. The sensor F3 and F4 in 90% water in DMSO show Aggregation-Caused Quenching (ACQ) behavior which results in weak fluorescent emission. After the addition of melamine, the fluorescent signals are selectively enhanced based on the de-aggregation of fluorophore. The sensor F4 provided a detection limit for melamine at 0.8 ppm. On the other hands, the sensor F5 which exhibits an Aggregation-Induced Emission Enhancement (AIEE) in aqueous DMSO shows selective florescence quenching toward melamine upon de-aggregation. The Stern-Volmer constant (Ksv) for signal quenching by melamine is 3 x 103 M-1 with the detection limit of 3.2 ppm.
DOI: 10.14457/cu.the.2015.396
title: FATTY ACID AND LIPID LEVELS IN CYANOBACTERIUM Synechocystis sp. PCC 6803 MUTANT OVEREXPRESSING plsX GENE

description: In this study, we successfully constructed the plsX- overexpressing strain of Synechocystis sp. PCC 6803 (OX_plsX strain), and further studied the effects of salt stress and nutrient modifications on growth, pigment contents of chlorophyll a and carotenoids, oxygen evolution rate or photosynthetic efficiency, lipid content and fatty acid composition, and transcript level of genes related to fatty acid synthesis compared to Synechocystis wild type. Initially, both strains were cultured in normal BG11 medium. Cell growth and intracellular pigment contents of OX_plsX strain were not different from those of wild type, as well as their oxygen evolution rate. However, both total lipid and unsaturated lipid contents of OX_plsX strain were higher than those of wild type. After that, effect of salt stress and nutrient modifications on cell lipid and fatty acid production were studied. It was found that sodium chloride at 100 mM concentration could induce the accumulation of total lipid in OX_plsX strain higher than wild type, up to about 1.3 fold whereas unsaturated lipid content of OX_plsX strain was higher than wild type in all salt stress studied. The fatty acid composition from GC-MS analysis consisted of saturated and unsaturated fatty acids including palmitic acid (C16:0), stearic acid (C18:0), pailmitoleic acid (C16:1), oleic acid (C18:1), linoleic acid (C18:2) and α-linolenic acid (C18:3). We found that salt stress effectively influenced the intracellular composition ratio of saturated and unsaturated fatty acids. On the other hand, after transferring log-phase growing cells into adapted BG11 medium, with nitrogen deficiency or carbon source supplementation of 0.4% acetate (6.7 mM concentration), acetate supplementation enabled OX_plsX strain to accumulate more total lipids and unsaturated lipids of about 1.3 and 2.9 fold, respectively, when compared to wild type. Next, we aligned the amino sequence of Synechocystis plsX compared with the amino sequence of cyanobacterium Anabaena sp. PCC 7120 and Synechococcus sp. PCC 7002 PlsXs. They showed high identity at 65.77% and 72.70%, respectively, whereas the identity comparing with plant Arabidopsis thaliana glycerol-3-phosphate acyltransferase was about 16.09%. The identity between Synechocystis PlsX and bacterial Escherichia coli PlsX and Bacillus subtilis PlsX were 36.72% and 42.42%, respectively. Phylogenetic tree analysis suggests that Synechocystis plsX may be classified into phosphate acyltransferase enzyme Altogether, plsX gene had a crucial role in fatty acid synthesis since the overexpression of plsX gene enhanced the lipid accumulation in Synechocystis cells. Also, the acetate supplementation could induce the lipid production in both wild type and plsX-overexpressing strains.
DOI: 10.14457/cu.the.2015.397
title: Pyrenyl truxenes as materials in organic light-emitting diodes

description: A new series of truxene derivatives with different numbers of dipyrenylcarbazole substituents have been synthesized via C-N cross-coupling. The Cu-catalyzed C-N coupling between the iodinated truxene core and dipyrenylcarbazole thus provides the target molecules (1-3) which are characterized by 1H-NMR, 13C-NMR and MALDI-TOF mass spectroscopy. These compounds emitted in the blue region (lem= 421 to 423 nm) and showed excellent thermal stabilities (Td10% above 440°C) suitable for application in optoelectronic devices. All compounds were used as hole-transporting non-doped emitters and BCP as a hole blocking layer in the OLEDs with the structure of ITO/PEDOT:PSS/1–3/BCP/LiF:Al. All devices emitted deep blue color according to the CIE coordinates (CIE, x= 0.15, y= 0.10 to 0.19) with high luminance efficiencies as compared to the reference device using NPB. Among the three materials, compound 2 could give lead to the best device performance with high maximum brightness of 8,001 cd/m2 at 9.6 V and turn-on voltage (Von) at 3.4 V. In addition, the hole-transport properties of these compounds compared with the commercial standard NPB were investigated using devices configuration of ITO/PEDOT:PSS/1–3/Alq3/LiF:Al. All devices displayed a bright green emission of Alq3 (lem= 512 to 517 nm, CIE 0.26, 0.50). Their ability as HTL for green OLEDs was comparable to a common hole-transporter NPB. The device based on 2 exhibited the best performance with highest maximum brightness of 44,773 cd/m2 at 10.8 V and turn-on voltage (Von) at 2.8 V.
DOI: 10.14457/cu.the.2015.398
title: Automatic oil palm detection and identification from aerial images using multi-scale clustering and normalized cross correlation

description: Oil palm cultivation is one of the most important occupation in South East Asia. Since oil palm plantation covers the wide range of areas, it is very difficult to count the numbers of oil palms manually. This thesis presents the new methods to detect and identify an individual of oil palms in plantation areas from aerial images regardless of their sizes using features including shape and texture. The proposed methods can handle the problem of oil palm identification from aerial image when oil palms are too close to each other such that they are identified as single oil palm. The processes of oil pam detection and identification consist of non-oil palm components and noise filtering, distinguishing oil palms from non-oil palm components (e.g., grass, weed, road, pond or swamp), identifying individual oil palms and counting the numbers of oil palms. In this thesis, oil palms can be detected and distinguished from non-oil palm components by using Butterworth low-pass filter on Fourier spectrum in frequency domain and template matching based on normalized cross correlation. Then the multi-scale clustering method is used to separate the oil palm stand into individual oil palms. The proposed method is used to estimate the population of oil palms on a set of 21 aerial images. All the aerial images were captured by mounting a digital camera on the model airplane that was controlled to fly over the plantation areas. Each image was taken from different view and location. The experimental results show that the proposed methods can detect and identify oil palms correctly with the recognition rate at 96.34%
DOI: 10.14457/cu.the.2015.399
title: DEVELOPMENT OF POLYPROPYLENE COMPOSITES AND POLYLACTIC ACID COMPOSITES CONTAINING CELLULOSE FIBRIL PREPARED BY DISSOLUTION/PRECIPITATION TECHNIQUE

description: The aim of this research is to develop polypropylene (PP) and polylactic acid (PLA) composites reinforced with cellulose fibril which prepared from the novel technique via the dissolution and precipitation of cellulosic materials. Cellulose fibril was prepared from the dissolution of microcrystalline cellulose in NaOH/urea/distilled water (7:12:81 by weight) solution at -5 °C, followed by the addition of starch solution which plays a role as the dispersing agent and performs the anti-coagulation effect. The mixed solution was precipitated in HCl solution to obtain cellulose fibril (CF) which has a web-like morphology with the diameter ranging from 10-40 nm. The high surface area of CF results in the increasing of water retention value (WRV). The surface of CF was modified with two different modifying agents including malenized soybean oil and hexadecyltrimethoxysilane. The results indicate that hexadecyltrimethoxysilane modified cellulose fibril (Silane-g-CF) is the more efficient reinforcement for polypropylene than malenized soybean oil modified cellulose fibril (Oil-g-CF), judged by the rising of onset thermal degradation temperature by 20 °C, the increasing of degree of crystallinity up to 11% and the shift of crystallization peak to higher temperature by 4 °C. Subsequently, Silane-g-CF reinforced PP and PLA composites with the filler content of 0.5, 1.0, 3.0 and 5.0 wt% were prepared by the twin screw extrusion, followed by the injection molding. The results indicate that Silane-g-CF can improve the thermal stability of PP and plays a role as the nucleating agent by increasing the crystallization temperature up to 5 °C as well as the degree of crystallinity. Silane-g-CF/PP composites show the higher impact resistance and Young’s modulus up to 20% and 10%, respectively when compared to neat PP. The enhancement of mechanical properties corresponds to the better compatibility and interfacial adhesion between CF and PP due to surface treatment, evidenced by the rough fracture surface of composites. In case of Silane-g-CF/PLA composites, the thermal stability is slightly increased. The nucleation effect of Silane-g-CF was observed clearly by DSC using the cooling rate of 1 °C/min. The glass transition temperature and the cold crystallization temperature are disappeared while the crystallization temperature is increased up to 5 °C as well as the increment of the degree of crystallinity by 30%. The addition of Silane-g-CF also improves the mechanical properties of PLA, resulting in the increasing of impact resistance up to 30%. At 0.5 wt% filler loading, the elongation at break of PLA is increased up to 50%. However, the decreasing of elongation at break, tensile strength, and Young’s modulus is observed when filler loading is increased, attributing to the plasticization effect caused by the long alkyl chain of organosilane modifying agent.
DOI: 10.14457/cu.the.2015.400
title: Surface enhanced Raman scattering using metal nanoparticles for carbofuran detection

description: Silver nanoparticles (AgNPs) have been widely used as substrates to enhance Raman signals of molecules oriented nearby the AgNPs surface. This improves the detection limit via surface-enhanced scattering (SERS) technique. In this research, the coupling reaction of diazonium ion combined with SERS provides a selective and sensitive detection method for trace analysis of carbofuran, which is one of the most toxic carbamate insecticides. Diazonium ion specifically reacts with carbofuran phenol created from the alkaline hydrolysis of carbofuran to generate azo dye complex. In SERS measurement, the generated azo compound is easily deposited on the surface of AgNPs by strong Ag–S bond; therefore, the strong Raman intensity of the azo dye can be observed. To quantify carbofuran, the ratio of Raman intensity at 1201 cm-1 over 1021 cm-1 were linearly plotted against the concentrations of carbofuran with R2 = 0.9891 in the range of 0.1–5 ppm. The limit of detection (LOD) is 0.729 ppm. Moreover, our proposed carbofuran detection method was insignificantly influenced by interferences e.g., small acid molecules and monosaccharide sugars. For practical analysis, the developed method of carbofuran detection was also studied in real agricultural products (e.g., rice, beans, peppers, sesame).