Pub Date : 2019-06-06DOI: 10.26534/kimika.v30i1.31-39
E. Magpantay, Ana Teresa B. Sucgang, M. Clemencia, T. Villar, M. Torio
The crude proteins were isolated using 0.125 M Tris-HCl with 50 mM NaCl at pH 7.4. The protein content of the crude extract was determined using the Lowry assay and was found to be 4.28 mg/mL. The major band which corresponds to the major protein has an approximate molecular weight of 20 KDa. The isolated crude proteins were subjected to enzymatic digestion using pepsin, trypsin, chymotrypsin, and thermolysin for 3, 4, 12, and 24 hours. The 24-hour digest was found to have the highest percent anti-Angiotensin Converting Enzyme (ACE) activity (36.02%) while the 12-hour digest was found to have the highest anti-oxidative activity (33.14%) using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The 24-hour digest was subjected to Ultra-Performance Liquid Chromatography (UPLC) to determine the peptide fraction responsible for the ACE inhibitory activity. Three peptide fractions (PF1, PF2 and PF3) were chosen and PF2 exhibited the highest percent inhibitory activity (32.21) against ACE. PF2 was subjected to thin layer chromatography (TLC) and the possible identity is EK based on the Rf value traveled by glutamic acid (E) (0.43) and Lysine (K) (0.13). In silico analysis was done to correlate the results with the presence of putative peptides with antioxidative and antihypertensive activities. Results showed that antihypertensive peptides EK, GS, TY, FNE, FP, LKA, PT, PP, FAL and antioxidative peptides IR and VPW were found based on the sequence of the protein in “Saba” banana. The presence of the antihypertensive peptide EK was verified using thin layer chromatography (TLC).
用0.125 M Tris-HCl和50 mM NaCl在pH 7.4条件下分离粗蛋白。采用Lowry法测定粗提物的蛋白质含量为4.28 mg/mL。与主蛋白对应的主带分子量约为20 KDa。分离得到的粗蛋白分别用胃蛋白酶、胰蛋白酶、凝乳胰蛋白酶和热溶酶进行酶解3、4、12和24小时。2,2-二苯基-1-吡啶酰肼(DPPH)测定结果表明，24小时消化液的抗血管紧张素转换酶(ACE)活性最高(36.02%)，12小时消化液的抗氧化活性最高(33.14%)。采用超高效液相色谱法(UPLC)测定24小时消化液中负责ACE抑制活性的肽段。选取PF1、PF2和PF3三个肽段，其中PF2对ACE的抑制率最高(32.21%)。对PF2进行薄层色谱(TLC)分析，根据谷氨酸(E)(0.43)和赖氨酸(K)(0.13)的Rf值推测，PF2可能是EK。通过计算机分析，将结果与推测的具有抗氧化和抗高血压活性的肽的存在联系起来。结果表明，根据“Saba”香蕉的蛋白序列，发现了EK、GS、TY、FNE、FP、LKA、PT、PP、FAL等抗高血压肽和IR、VPW等抗氧化肽。薄层色谱法证实了抗高血压肽EK的存在。
{"title":"Preliminary Assessment of the Antihypertensive and Antioxidative Activities of the Peptides from “Saba” Banana (Musa balbisiana Colla) Flesh","authors":"E. Magpantay, Ana Teresa B. Sucgang, M. Clemencia, T. Villar, M. Torio","doi":"10.26534/kimika.v30i1.31-39","DOIUrl":"https://doi.org/10.26534/kimika.v30i1.31-39","url":null,"abstract":"The crude proteins were isolated using 0.125 M Tris-HCl with 50 mM NaCl at pH 7.4. The protein content of the crude extract was determined using the Lowry assay and was found to be 4.28 mg/mL. The major band which corresponds to the major protein has an approximate molecular weight of 20 KDa. The isolated crude proteins were subjected to enzymatic digestion using pepsin, trypsin, chymotrypsin, and thermolysin for 3, 4, 12, and 24 hours. The 24-hour digest was found to have the highest percent anti-Angiotensin Converting Enzyme (ACE) activity (36.02%) while the 12-hour digest was found to have the highest anti-oxidative activity (33.14%) using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The 24-hour digest was subjected to Ultra-Performance Liquid Chromatography (UPLC) to determine the peptide fraction responsible for the ACE inhibitory activity. Three peptide fractions (PF1, PF2 and PF3) were chosen and PF2 exhibited the highest percent inhibitory activity (32.21) against ACE. PF2 was subjected to thin layer chromatography (TLC) and the possible identity is EK based on the Rf value traveled by glutamic acid (E) (0.43) and Lysine (K) (0.13). In silico analysis was done to correlate the results with the presence of putative peptides with antioxidative and antihypertensive activities. Results showed that antihypertensive peptides EK, GS, TY, FNE, FP, LKA, PT, PP, FAL and antioxidative peptides IR and VPW were found based on the sequence of the protein in “Saba” banana. The presence of the antihypertensive peptide EK was verified using thin layer chromatography (TLC).","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79264838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-06DOI: 10.26534/KIMIKA.V30I1.13-17
Shienna Marie Pontillas, M. Marquez, F. Sumera, R. Advíncula
Thin films made of cross-linked carbazole pendants of poly(ethylmethacrylate) deposited on indium tin oxide (ITO) was assessed for potential use as hole transport layer (HTL) in a fabricated photovoltaic cell configuration (ITO/PCDTBT/PCBM/Al). Before measurement, the film was designed to have uniform molecular weight, cross-linked carbazole for high electron mobility, high transmittance at the visible wavelength range and smoothness in morphology. Results showed that the film provided 70 times more of current value at open circuit voltage than without the film under light illumination, at optimized thickness from 15 to 25 cycles of deposition at 25 mV/s using cyclic voltammetry.
{"title":"Optimizing the property of cross-linked carbazole-based polymer for efficient hole transport in bulk-heterojunction photovoltaic device","authors":"Shienna Marie Pontillas, M. Marquez, F. Sumera, R. Advíncula","doi":"10.26534/KIMIKA.V30I1.13-17","DOIUrl":"https://doi.org/10.26534/KIMIKA.V30I1.13-17","url":null,"abstract":"Thin films made of cross-linked carbazole pendants of poly(ethylmethacrylate) deposited on indium tin oxide (ITO) was assessed for potential use as hole transport layer (HTL) in a fabricated photovoltaic cell configuration (ITO/PCDTBT/PCBM/Al). Before measurement, the film was designed to have uniform molecular weight, cross-linked carbazole for high electron mobility, high transmittance at the visible wavelength range and smoothness in morphology. Results showed that the film provided 70 times more of current value at open circuit voltage than without the film under light illumination, at optimized thickness from 15 to 25 cycles of deposition at 25 mV/s using cyclic voltammetry.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80802729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-03DOI: 10.26534/kimika.v30i1.1-3
Mohammed El Behery, A. Asada, F. Takeuchi, Tetsunari Kimura, E. Chatani, M. Tsubaki
A candidate human tumor suppressor gene 101F6 product was expressed successfully in Pichia pastoris yeast cells. The purified 101F6 protein was successfully incorporated into phospholipid bilayer nanodiscs with different sizes by employing two reconstitution methods; self-assembly and reconstitution into the preformed empty nanodisc. The reconstituted 101F6 protein could be reduced with ascorbate quickly and was very stable even at ambient temperatures.
{"title":"Elucidation of molecular functions of human tumor suppressor protein 101F6 by reconstitution into phospholipid bilayer nanodiscs","authors":"Mohammed El Behery, A. Asada, F. Takeuchi, Tetsunari Kimura, E. Chatani, M. Tsubaki","doi":"10.26534/kimika.v30i1.1-3","DOIUrl":"https://doi.org/10.26534/kimika.v30i1.1-3","url":null,"abstract":"A candidate human tumor suppressor gene 101F6 product was expressed successfully in Pichia pastoris yeast cells. The purified 101F6 protein was successfully incorporated into phospholipid bilayer nanodiscs with different sizes by employing two reconstitution methods; self-assembly and reconstitution into the preformed empty nanodisc. The reconstituted 101F6 protein could be reduced with ascorbate quickly and was very stable even at ambient temperatures.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74817027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-10DOI: 10.26534/kimika.v30i1.4-12
Rey Joseph J. Ganado, Jr. C. Franco Francisco
The increasing oil demand and exhaustion of reserves have initiated stimulus to search for new and sustainable sources of fuels and fine chemicals. Lignocellulosic biomass turned out to be a promising and renewable feedstock for these applications. 5-hydroxymethylfurfural (HMF) is one of the most promising building blocks for bio-based chemicals that can be derived from lignocellulosic biomass which can be potentially applied for large scale production. However, one of the main factors holding its transition is the need for sustainable, green and financially feasible processes. This review provides the studies made towards catalytic systems used for HMF production, as well as the various solvents and heating system applied. Research efforts to unravel the interactions among catalysts, solvents, and heating systems are encouraged, thereby engineering a synergistic conversion system for biomass valorization.
{"title":"Towards the Valorization of Biomass to 5-Hydroxymethylfurfural: A Promising Biochemical and Biofuel Feedstock","authors":"Rey Joseph J. Ganado, Jr. C. Franco Francisco","doi":"10.26534/kimika.v30i1.4-12","DOIUrl":"https://doi.org/10.26534/kimika.v30i1.4-12","url":null,"abstract":"The increasing oil demand and exhaustion of reserves have initiated stimulus to search for new and sustainable sources of fuels and fine chemicals. Lignocellulosic biomass turned out to be a promising and renewable feedstock for these applications. 5-hydroxymethylfurfural (HMF) is one of the most promising building blocks for bio-based chemicals that can be derived from lignocellulosic biomass which can be potentially applied for large scale production. However, one of the main factors holding its transition is the need for sustainable, green and financially feasible processes. This review provides the studies made towards catalytic systems used for HMF production, as well as the various solvents and heating system applied. Research efforts to unravel the interactions among catalysts, solvents, and heating systems are encouraged, thereby engineering a synergistic conversion system for biomass valorization.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74708730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-28DOI: 10.26534/KIMIKA.V29I2.23-29
Kris Corinne D. C. Laserna, C. D. Deguit, Wilfred F. Ong, D. Camacho
A halogen-free ionic liquid (IL) designed with long alkyl chain anion is reported. 1-methylimidazolium stearate (MIM stearate) synthesized through Bronsted acid-base reaction has shown improved lipophilic character and is able to penetrate bacterial cell walls. Antimicrobial activities against Gram-negative bacteria, Escherichia coli, and Pseudomonas aeruginosa were observed. Anti-biofilm assays showed effectivity against the biofilm of Pseudomonas aeruginosa. At 50 µg/mL the %biofilm inhibition of MIM stearate towards P. aeruginosa biofilm formation is comparable to the Bromofuran positive control. Brine shrimp lethality assay showed weak toxicity indicating the IL to be safe and benign. The synthesized MIM stearate showed good promise as an antimicrobial and anti-biofilm agent.
{"title":"Lipophilic halogen-free ionic liquid with antibacterial and anti-biofilm activities against Pseudomonas aeruginosa","authors":"Kris Corinne D. C. Laserna, C. D. Deguit, Wilfred F. Ong, D. Camacho","doi":"10.26534/KIMIKA.V29I2.23-29","DOIUrl":"https://doi.org/10.26534/KIMIKA.V29I2.23-29","url":null,"abstract":"A halogen-free ionic liquid (IL) designed with long alkyl chain anion is reported. 1-methylimidazolium stearate (MIM stearate) synthesized through Bronsted acid-base reaction has shown improved lipophilic character and is able to penetrate bacterial cell walls. Antimicrobial activities against Gram-negative bacteria, Escherichia coli, and Pseudomonas aeruginosa were observed. Anti-biofilm assays showed effectivity against the biofilm of Pseudomonas aeruginosa. At 50 µg/mL the %biofilm inhibition of MIM stearate towards P. aeruginosa biofilm formation is comparable to the Bromofuran positive control. Brine shrimp lethality assay showed weak toxicity indicating the IL to be safe and benign. The synthesized MIM stearate showed good promise as an antimicrobial and anti-biofilm agent.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84478913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-27DOI: 10.26534/kimika.v29i2.30-35
Erick Gonzales, Karl Gabriel M. Lloren, Jihan S. Al-shdifat, Lica B. Valdez, Krizzia Rae Gines, Emmanuel V. Garcia
Studies regarding particle size distribution, particularly in espressos are surprisingly few. Particle size distribution (PSD) is a plot that displays the average diameter versus percentage volume of the particles present in a sample. With increased awareness amongst coffee drinkers, a study aiming to report the effects of different pressure on particle size distribution of espresso from four different coffee blends was conducted. The method involved pulling of espresso shots at 7, 9, and 11 bar (or atm) from different coffee blends labeled as MA, CO, AL, and MO. Laser diffraction analysis showed different particle size groupings for each set of extraction pressure. Fine particles are within 1.20 to 28.70 µm. The most abundant particle size is centered at 185.4 µm. The particle size distribution of coffee blends composed of 100% Arabica coffee (AL and MO) but sourced from different locations, showed four similar modes or size ranges centered at 3.523, 13.005, 28.70, and 185.4 µm regardless of the extraction pressure or the coffee source. On the other hand, the coffee blends composed of different ratios of Arabica and Robusta (MA and CO) showed different modes depending on the pressure. This indicates the potential of PSD for characterizing the purity of a coffee blend. The particle size distribution can also give insights as to the sensory attributes of the espresso coffee.
{"title":"Effect of Pressure on the Particle Size Distribution of Espresso Coffee","authors":"Erick Gonzales, Karl Gabriel M. Lloren, Jihan S. Al-shdifat, Lica B. Valdez, Krizzia Rae Gines, Emmanuel V. Garcia","doi":"10.26534/kimika.v29i2.30-35","DOIUrl":"https://doi.org/10.26534/kimika.v29i2.30-35","url":null,"abstract":"Studies regarding particle size distribution, particularly in espressos are surprisingly few. Particle size distribution (PSD) is a plot that displays the average diameter versus percentage volume of the particles present in a sample. With increased awareness amongst coffee drinkers, a study aiming to report the effects of different pressure on particle size distribution of espresso from four different coffee blends was conducted. The method involved pulling of espresso shots at 7, 9, and 11 bar (or atm) from different coffee blends labeled as MA, CO, AL, and MO. Laser diffraction analysis showed different particle size groupings for each set of extraction pressure. Fine particles are within 1.20 to 28.70 µm. The most abundant particle size is centered at 185.4 µm. The particle size distribution of coffee blends composed of 100% Arabica coffee (AL and MO) but sourced from different locations, showed four similar modes or size ranges centered at 3.523, 13.005, 28.70, and 185.4 µm regardless of the extraction pressure or the coffee source. On the other hand, the coffee blends composed of different ratios of Arabica and Robusta (MA and CO) showed different modes depending on the pressure. This indicates the potential of PSD for characterizing the purity of a coffee blend. The particle size distribution can also give insights as to the sensory attributes of the espresso coffee.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85843878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-27DOI: 10.26534/KIMIKA.V29I2.36-43
Laurenzo D V Alba, Mario Enriquez
Paclitaxel, a chemotherapeutic drug used to inhibit mitosis in cancer cells, requires the use of the solubilizer Cremophor EL due to its poor water solubility. However, Cremophor EL is associated with adverse reactions following chemotherapy. This work reports the synthesis of an alternative solubilizing agent for paclitaxel. Two generations of dendritic lysine were coupled onto both ends of PEG-4000 via reaction of fluorenylmethyloxycarbonyl (FMOC)-lysine-FMOC-OH with dicyclohexylcarbodiimide (DCC)-mediated condensation, and deprotection with 30% piperidine. Cholic acid was attached to the terminal amino groups through the use of DCC/n-hydroxysuccinimide. Synthesis steps were monitored and confirmed by electrospray ionization mass spectroscopy. The results suggest that the synthesized polymer is a viable solubilizing agent for delivery of paclitaxel. Additional studies are required to assess its safety and stability.
{"title":"Synthesis of cholic acid-terminated dendritic lysine-block-poly(ethylene glycol)-block-dendritic lysine and its enhanced ability to solubilize Paclitaxel in water","authors":"Laurenzo D V Alba, Mario Enriquez","doi":"10.26534/KIMIKA.V29I2.36-43","DOIUrl":"https://doi.org/10.26534/KIMIKA.V29I2.36-43","url":null,"abstract":"Paclitaxel, a chemotherapeutic drug used to inhibit mitosis in cancer cells, requires the use of the solubilizer Cremophor EL due to its poor water solubility. However, Cremophor EL is associated with adverse reactions following chemotherapy. This work reports the synthesis of an alternative solubilizing agent for paclitaxel. Two generations of dendritic lysine were coupled onto both ends of PEG-4000 via reaction of fluorenylmethyloxycarbonyl (FMOC)-lysine-FMOC-OH with dicyclohexylcarbodiimide (DCC)-mediated condensation, and deprotection with 30% piperidine. Cholic acid was attached to the terminal amino groups through the use of DCC/n-hydroxysuccinimide. Synthesis steps were monitored and confirmed by electrospray ionization mass spectroscopy. The results suggest that the synthesized polymer is a viable solubilizing agent for delivery of paclitaxel. Additional studies are required to assess its safety and stability.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78364574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-05DOI: 10.26534/kimika.v29i2.1-6
M. J. Aguila, Joshua P. Gemperoso, King Bryan C. Gabog, A. Magsino
Deep eutectic solvents (DESs) are considered as better alternative solvents in chemical and physical processes. The binary mixture of urea and potassium sodium tartrate is explored in this study. A eutectic system is determined at composition made up of 33% potassium sodium tartrate and 67% urea (1:2 molar ratio). This eutectic system has a freezing point of 19.83 ± 0.76 °C, density of 1.1971 ± 0.0003 g mL-1, and viscosity of 34.4226 ± 0.0665 cP. The most stable conformation for the adduct of urea and potassium sodium tartrate with water molecules was determined through density functional calculations. The gas phase total energy for the adduct was determined as -5576863 kJ mol-1. Electrostatic interactions between the cations and the carboxylate sites are present, H-bonding between protons of urea and the hydroxyl oxygen of the tartrate, and intramolecular H-bonding between the hydroxyl and carboxylate sites of tartrate are accounted in the structure. The total energy associated with nonbonding interactions is computed as -826 kJ mol-1, which suggests that these interactions stabilize the formation of the DES system of potassium sodium tartrate and urea.
深共晶溶剂(DESs)被认为是化学和物理过程中较好的替代溶剂。对尿素和酒石酸钾钠二元混合物进行了研究。共晶体系由33%酒石酸钾钠和67%尿素(1:2摩尔比)组成。该共晶体系的凝固点为19.83±0.76℃，密度为1.1971±0.0003 g mL-1，粘度为34.4226±0.0665 cP。通过密度函数计算确定了尿素和酒石酸钾钠加合物与水分子的最稳定构象。加合物的气相总能为-5576863 kJ mol-1。阳离子和羧酸盐位点之间存在静电相互作用，尿素的质子和酒石酸盐的羟基氧之间存在h键，酒石酸盐的羟基和羧酸盐位点之间存在分子内h键。与非键相互作用相关的总能量计算为-826 kJ mol-1，这表明这些相互作用稳定了酒石酸钾钠和尿素的DES体系的形成。
{"title":"Eutectic System Based on Urea and Potassium Sodium Tartrate","authors":"M. J. Aguila, Joshua P. Gemperoso, King Bryan C. Gabog, A. Magsino","doi":"10.26534/kimika.v29i2.1-6","DOIUrl":"https://doi.org/10.26534/kimika.v29i2.1-6","url":null,"abstract":"Deep eutectic solvents (DESs) are considered as better alternative solvents in chemical and physical processes. The binary mixture of urea and potassium sodium tartrate is explored in this study. A eutectic system is determined at composition made up of 33% potassium sodium tartrate and 67% urea (1:2 molar ratio). This eutectic system has a freezing point of 19.83 ± 0.76 °C, density of 1.1971 ± 0.0003 g mL-1, and viscosity of 34.4226 ± 0.0665 cP. The most stable conformation for the adduct of urea and potassium sodium tartrate with water molecules was determined through density functional calculations. The gas phase total energy for the adduct was determined as -5576863 kJ mol-1. Electrostatic interactions between the cations and the carboxylate sites are present, H-bonding between protons of urea and the hydroxyl oxygen of the tartrate, and intramolecular H-bonding between the hydroxyl and carboxylate sites of tartrate are accounted in the structure. The total energy associated with nonbonding interactions is computed as -826 kJ mol-1, which suggests that these interactions stabilize the formation of the DES system of potassium sodium tartrate and urea.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79689559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-04DOI: 10.26534/KIMIKA.V29I2.7-22
Jina Denise R. Galiza, Rhodora F. Nicdao, A. Guidote
This study examined teachers’ content knowledge (CK) in chemistry and its relationship to teachers’ chemistry background, teaching experience, involvement in professional development and self-efficacy It was further investigated which variables predicted the level of content knowledge (CK) of one hundred public secondary chemistry teachers. The data shows that the majority of science teachers have low level of CK in Chemistry. Teaching experience, professional development, chemistry background, and self-efficacy were significantly related to the CK of teachers. Teachers' professional development and self-efficacy predicted the CK of teachers.
{"title":"Educational Attainment, Teaching Experience, Professional Development and Self-Efficacy as Predictors of Chemistry Content Knowledge: Implication for the Development of a National Promotion Examination","authors":"Jina Denise R. Galiza, Rhodora F. Nicdao, A. Guidote","doi":"10.26534/KIMIKA.V29I2.7-22","DOIUrl":"https://doi.org/10.26534/KIMIKA.V29I2.7-22","url":null,"abstract":"This study examined teachers’ content knowledge (CK) in chemistry and its relationship to teachers’ chemistry background, teaching experience, involvement in professional development and self-efficacy It was further investigated which variables predicted the level of content knowledge (CK) of one hundred public secondary chemistry teachers. The data shows that the majority of science teachers have low level of CK in Chemistry. Teaching experience, professional development, chemistry background, and self-efficacy were significantly related to the CK of teachers. Teachers' professional development and self-efficacy predicted the CK of teachers.","PeriodicalId":17914,"journal":{"name":"KIMIKA","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90241884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-07DOI: 10.26534/kimika.v29i1.41-50
Shienna Marie Pontillas, F. Sumera, R. Advíncula
Carbazole containing polymers have captured the interest of researchers for use in optoelectronics. For an important material to exhibit its optoelectronic properties intrinsic uniformity in the molecular level is required. Thus, a monomer of ethyl methacrylate with pendant carbazole group was synthesized and polymerized via Reversible Addition-Fragmentation Chain Transfer (RAFT) to produce polymers with controlled molecular weight distribution and narrow polydispersity index (PDI). This method of polymerization was compared with that of free radical polymerization by gel permeation chromatography (GPC). The RAFT’s polymerization kinetics was observed to follow a plot of number average molecular weight (Mn) versus % conversion, characteristic of living polymerization. It was also shown to possess polymer chain extension capability. The structure of the monomer and the polymers were characterized by Fourier-Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR).
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