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Jang K.S.,Chonnam National University | Shin D.S.,Sogang University | Srisook E.,Burapha UniversityChonburi | Song H.-C.,Chonnam National University | Chi D.Y.,Sogang University
Tetrahedron | Year: 2016

Divergent functionalized 8-methoxyquinaldines were synthesized via regioselective debromination, 1,3-bromine shift process, aromatization with treatment of a strong base, nucleophilic substitution reaction at the C7 position using amines and cyanide as a nucleophile in the absence of a metal source and a catalyst from an unusual electrophilic aromatic addition (AdEAr) reaction products 7 and 8. In addition, quinaldine-7,8-dione was prepared by presence of CAN (ceric ammonium nitrate) in AcOH and H2O for 10 min at room temperature from N-(alkylamino)-8-methoxyquinalidines. During the AdEAr reaction, new stereoselective dearomatized addition products were generated via discriminative reaction routes depending on the methoxy and bromine occupancy position. The AdEAr reaction not only allowed for the functionalization of electron rich-fused heterocyclic arenes, but also provided a new synthetic route to an alternative mechanism for electrophilic aromatic substitution reactions. © 2016

Namwong L.,King Mongkut's University of Technology Thonburi | Authayanun S.,Srinakharinwirot UniversityNakhon Nayok | Saebea D.,Burapha UniversityChonburi | Patcharavorachot Y.,King Mongkut's University of Technology Thonburi | Arpornwichanop A.,Chulalongkorn University
Journal of Power Sources | Year: 2016

Proton-conducting solid oxide electrolysis cells (SOEC-H+) are a promising technology that can utilize carbon dioxide to produce syngas. In this work, a detailed electrochemical model was developed to predict the behavior of SOEC-H+ and to prove the assumption that the syngas is produced through a reversible water gas-shift (RWGS) reaction. The simulation results obtained from the model, which took into account all of the cell voltage losses (i.e., ohmic, activation, and concentration losses), were validated using experimental data to evaluate the unknown parameters. The developed model was employed to examine the structural and operational parameters. It is found that the cathode-supported SOEC-H+ is the best configuration because it requires the lowest cell potential. SOEC-H+ operated favorably at high temperatures and low pressures. Furthermore, the simulation results revealed that the optimal S/C molar ratio for syngas production, which can be used for methanol synthesis, is approximately 3.9 (at a constant temperature and pressure). The SOEC-H+ was optimized using a response surface methodology, which was used to determine the optimal operating conditions to minimize the cell potential and maximize the carbon dioxide flow rate. © 2016 Elsevier B.V.

Chokpaiboon S.,Chulalongkorn University | Unagul P.,National Science and Technology Development Agency | Kongthong S.,National Science and Technology Development Agency | Danwisetkanjana K.,National Science and Technology Development Agency | And 3 more authors.
Tetrahedron Letters | Year: 2016

The novel compounds, astronypyrone, astronyquinone, and astronyurea, together with three known compounds, xestodecalactone A, ent-coryoctalactone B, and dimethoxy-O-methylpulvinone were isolated from the marine-derived fungus Astrosphaeriella nypae BCC 5335. Their structures were elucidated on the basis of NMR spectroscopy and mass spectrometry data. Astronypyrone possesses a 2-pyrone derivative fused with a tetrahydrofuran moiety via a dihydropyran unit, while the 2-pyrone ring is substituted by a naphthoquinone skeleton in astronyquinone. © 2016 Elsevier Ltd. All rights reserved.

Dongbang W.,Burapha UniversityChonburi | Pirompugd W.,Burapha UniversityChonburi
International Journal of Agricultural and Biological Engineering | Year: 2015

The present study investigated the drying kinetics of anchovy experimentally using centrifugal fluidized bed technique. The main purpose was to experimentally investigate the effect of the inlet air temperature on the drying kinetics of anchovy in a centrifugal fluidized bed dryer, to fit the experimental data to the widely used mathematical models of drying. Further, the effective moisture diffusivity and activation energy in anchovy drying were investigated in the current work. The drying experiment was conducted at drying air temperatures ranging over 70-120°C. The air velocity and rotating speed of the air-distributor were fixed at 1.5 m/s and 150 r/min, respectively. Pressure drop across bed was approximately 390 Pa, while the layer height was fixed at approximately 2 cm. The anchovies were dried starting from 412% db down to 16% db; drying time ranged from 64 min to 172 min. It was found that the drying temperature was a significant factor in decreasing the moisture content, moisture diffusivity and drying time. The moisture diffusivity and activation energy were investigated at 0.11×10-9-0.25×10-9 m2/s and 20.32 kJ/mol, respectively. When compared to existing models, the Midilli model proved to be in good agreement with change in moisture ratio. © 2015, Chinese Society of Agricultural Engineering. All rights reserved.

Jaratjaroonphong J.,Burapha UniversityChonburi | Tuengpanya S.,Burapha UniversityChonburi | Ruengsangtongkul S.,Burapha UniversityChonburi
Journal of Organic Chemistry | Year: 2015

In this paper, N-Boc and N-Cbz protected α-branched amines are synthesized directly from commercially available aromatic/heteroaromatic compounds, aldehydes, and tert-butyl or benzyl carbamate bearing a variety of substituents. Bismuth(III) triflate is found to be a highly effective catalyst for this one-pot, three-component coupling reaction. In addition, the use of mild reaction conditions, low catalytic loading, easy removal of the N-protective group, and one-step synthesis under "open-flask" are advantages of the present procedure. © 2014 American Chemical Society.

Thongnopakun S.,Burapha UniversityChonburi | Maharachpong N.,Burapha UniversityChonburi | Abdullakasim P.,Burapha UniversityChonburi
Journal of the Medical Association of Thailand | Year: 2016

Background and objective: Youth is a “crisis period”, as it is a transitional period between childhood and adulthood. This period incites the youth to have curiosity, especially to sexual contents. As a result, they have higher risk behavior leading to the percentage of newly HIV infected persons among youth in the eastern region that is proportionally higher. This research aimed to study factors related to sexual health behaviors among youth in universities located in the eastern region of Thailand. Material and Method: This research was a cross-sectional survey research. The data collection process was conducted from June-September 2011. There were 405 informants, who participated in this study. They were students from both government and private universities in the eastern region. The age of the youth was 20-24 years old. The students’ field of study varied. The tool of the study was self-answered questionnaires. The quantitative data were analyzed using descriptive statistics and presented as frequency, percentage, average score, deviation standard scale, and it was analyzed by Crude odds ratio. Results: It was found that three-fifths of the youth already had sexual experiences, and more than half did not use condoms during their first-time sex. Regarding sexual behavior, it was found that almost one-fourth of the students did not use condoms at any time when they had sex, and did not negotiate for safer safe when they had sex. The statistical significance was (p = 0.012, Crude OR = 1.65). Youth who already had sex had more chances to have unprotected sex than those who never had sex (p = 0.014, Crude OR = 1.64). Youth who had casual sex partner(s) had more chances to have unprotected sex than youth who did not have casual sex partner(s) (p = 0.026, Crude OR = 1.78). Youth who had little knowledge on AIDS and sexually transmitted diseases would have more chances to have unprotected sex than youth who had high level of knowledge on these topics (p = 0.010, Crude OR = 2.83). Youth who had negative attitudes towards safe sex would have more chance to have unprotected sex than youth who had positive attitudes towards safe sex (p = 0.002, Crude OR = 3.65). Conclusion: More than half of the informants had sexual experiences. They did not use condoms during their first-time intercourse. The study found that the factors, which had a relationship with sexual behaviors showing statistical significance, were as follows: gender, having sex in the past 3 months, having casual sex partner(s) in the past 3 months, knowledge on AIDS and sexually transmitted diseases, and attitude towards safe sex. This study’s recommendation suggests that the educational institutions and parents should contribute to the knowledge and attitudes, and should support the life skills for safe sex behavior. © 2016, Medical Association of Thailand. All rights reserved.

Potipat J.,Burapha UniversityChonburi | Potipat J.,Rambhai Barni Rajabhat University | Tangkrock-Olan N.,Burapha UniversityChonburi | Helander H.F.,Gothenburg University
EnvironmentAsia | Year: 2015

The sediment samples from 24 stations in coastal area of Chanthaburi Province were collected during March 2012 to March 2013 and analyzed for heavy metal contents (Pb,Cd, Ca, Fe, Cu and Zn), pH, onganic matters and grain sizes. The correlation analyses showed that heavy metal conceatrntions were affeeted by the content of organic matter and the size of clay particles. The evoluation of the quality of sediment was carried out using the geoaccumulation index (Igeo)and the enrichment factor (EF) as well at the comparison with those in t4e Thailand’s sediment quality guideiine (SQG) values. The results oe the geoaccumulation index and the enrichment factor values of the heavy metals content in the sediments revealed that the study area was unpolluted and not enriched, respectively. The relationship between the heavy metals concentration and the organic matter, and the clay particle wns proposed try using the multiple regression equations. © 2015 Thai Society of Higher Eduation Institutes on Environment

Subongkot T.,Burapha UniversityChonburi | Ngawhirunpat T.,Silpakorn UniversityNakhon Pathom
International Journal of Nanomedicine | Year: 2015

The purpose of this study was to investigate the effect of ultradeformable liposome components, Tween 20 and terpenes, on vesicle fluidity. The fluidity was evaluated by electron spin resonance spectroscopy using 5-doxyl stearic acid and 16-doxyl stearic acid as spin labels for phospholipid bilayer fluidity at the C5 atom of the acyl chain near the polar head group (hydrophilic region) and the C16 atom of the acyl chain (lipophilic region), respectively. The electron spin resonance study revealed that Tween 20 increased the fluidity at the C5 atom of the acyl chain, whereas terpenes increased the fluidity at the C16 atom of the acyl chain of the phospholipid bilayer. The increase in liposomal fluidity resulted in the increased skin penetration of sodium fluorescein. Confocal laser scanning microscopy showed that ultradeformable liposomes with terpenes increase the skin penetration of sodium fluorescein by enhancing hair follicle penetration. © 2015 Subongkot and Ngawhirunpat.

Yasarawan N.,Burapha UniversityChonburi | Thipyapong K.,Burapha UniversityChonburi | Ruangpornvisuti V.,Chulalongkorn University
Journal of Molecular Structure | Year: 2016

Alanylaspartic dipeptide (AlaAsp) and zinc(II)-flavonol complex could represent a metal-binding site in proteins and a metal-ion releasing agent, respectively. Chelation of zinc(II) by either AlaAsp or flavonol ligands in aqueous solution has been examined using DFT methods with polarizable continuum model (PCM/DFT). Coordination geometry, complexation stoichiometry, coordination bond strength, preferable metal-binding site on ligands and effect of water coordination on the stability of complexes have been addressed. In several cases, the long-range corrected density functional CAM-B3LYP allows the most accurate prediction of both structural and spectroscopic data. The preferential transfer of flavonol-chelated zinc(II) to AlaAsp under solvation is attainable through the ligand-exchange reaction. The energy barrier of such reaction is significantly dependent on the degree of hydrogen bonding within the transition state. In summary, either hydroxylation or methoxylation at particular positions on the 3-hydroxyflavone backbone significantly affects the reactivity of flavonol chelates in the metal-ion transfer. © 2015 Elsevier B.V.

Chindaprasirt P.,Khon Kaen University | Rattanasak U.,Burapha UniversityChonburi
Construction and Building Materials | Year: 2016

Cement pipes have been used to transfer the domestic sewage and industrial wastewater due to its cost effectiveness. However, they faced the acid attack problem owing mainly to the high content of calcium compounds in the composite. Coating of cement pipes is one of the methods to protect the cement pipe surface from acid attack. An alumino-silicate geopolymer provides excellent mechanical properties and resistance to severe environments. Therefore, this research proposed the covering of cement-based materials with geopolymer. The covered specimens were immersed in deionized water (pH = 6.1), 0.005% H2SO4 (pH = 3), 5% MgSO4 (pH = 7.7) and 3% H2SO4 (pH = 0.3, representing the worst condition in the wastewater system). The pH and Ca2+ content of immersion solutions were measured. In addition, mechanical and chemical properties of geopolymeric-covering material were tested after the immersion in solutions for 30 and 90 days. © 2016 Elsevier Ltd. All rights reserved.

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