Pub Date : 2023-10-25DOI: 10.31276/vjst.65(10db).01-06
Thi Kim Trang Do, Ngoc Anh Dao, Bao Tram Tran, Thi Chien Truong, Minh Nam Nguyen, Van Tuan Tran, Xuan Tao Vu
Cordyceps militaris is one of the important medicinal fungi in traditional medicine. The fruiting body of C. militaris contains various bioactive compounds that have health-enhancing effects and support the treatment of various diseases. Therefore, this fungus is a potential source of medicinal materials for the development of healthcare products. The search for new strains of C. militaris with high yield, quality, and uniqueness is always of great interest. This study has provided new findings on some biological characteristics of an albino strain of C. militaris isolated in Vietnam. The albino strain of C. militaris SHBTQ was isolated and accurately identified based on morphological characteristics and the ITS (internal transcribed spacer) sequence of ribosomal DNA. The mycelial of C. militaris SHBTQ is white and remains stable for five successive generations. The most suitable carbon and nitrogen sources for the growth of the albino SHBTQ strain were sucrose and yeast extract, respectively. Notably, the SHBTQ strain is capable of forming fruiting bodies, with an average fresh fruiting body yield of 30 g/box, a biological efficiency of 12.2%, and a cordycepin content of 10.45 mg/g of dried fruiting bodies. This newly discovered strain offers great potential for further applications in production.
蛹虫草是传统医学中重要的药用真菌之一。蚕豆子实体含有多种生物活性化合物，具有促进健康和支持治疗多种疾病的作用。因此，这种真菌是开发保健产品的潜在药材来源。寻找高产、优质、独特的军孢杆菌新品种一直是人们关注的焦点。本研究对越南分离的一株白化菌的一些生物学特性有了新的发现。利用形态学特征和核糖体DNA ITS (internal转录间隔物)序列，分离得到一株白化菌militaris SHBTQ。SHBTQ的菌丝呈白色，连续5代保持稳定。蔗糖和酵母浸膏分别是最适合白化菌SHBTQ生长的碳源和氮源。值得注意的是，SHBTQ菌株能够形成子实体，其平均鲜子实体产量为30 g/箱，生物效率为12.2%，干子实体中虫草素含量为10.45 mg/g。这种新发现的菌株在进一步的生产应用中具有很大的潜力。
{"title":"Study on some biological characteristics of the albino strain of medicinal fungus Cordyceps militaris isolated in Vietnam","authors":"Thi Kim Trang Do, Ngoc Anh Dao, Bao Tram Tran, Thi Chien Truong, Minh Nam Nguyen, Van Tuan Tran, Xuan Tao Vu","doi":"10.31276/vjst.65(10db).01-06","DOIUrl":"https://doi.org/10.31276/vjst.65(10db).01-06","url":null,"abstract":"Cordyceps militaris is one of the important medicinal fungi in traditional medicine. The fruiting body of C. militaris contains various bioactive compounds that have health-enhancing effects and support the treatment of various diseases. Therefore, this fungus is a potential source of medicinal materials for the development of healthcare products. The search for new strains of C. militaris with high yield, quality, and uniqueness is always of great interest. This study has provided new findings on some biological characteristics of an albino strain of C. militaris isolated in Vietnam. The albino strain of C. militaris SHBTQ was isolated and accurately identified based on morphological characteristics and the ITS (internal transcribed spacer) sequence of ribosomal DNA. The mycelial of C. militaris SHBTQ is white and remains stable for five successive generations. The most suitable carbon and nitrogen sources for the growth of the albino SHBTQ strain were sucrose and yeast extract, respectively. Notably, the SHBTQ strain is capable of forming fruiting bodies, with an average fresh fruiting body yield of 30 g/box, a biological efficiency of 12.2%, and a cordycepin content of 10.45 mg/g of dried fruiting bodies. This newly discovered strain offers great potential for further applications in production.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135168124","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 : 2023-09-15DOI: 10.31276/vjste.65(3).80-84
Thi Thanh Loan Nguyen, Thi Van Anh Pham, Thi Xoan Le
The current study was designed to investigate the anti-hypertensive effects of a standardised flavonoid extract from Diospyros kaki L.f leaves (DK extract) on cortisone acetate-induced hypertensive rats. Hypertension was induced in Wistar rats by subcutaneously injecting 2.5 mg cortisone acetate daily and by maintaining the rats on a 1% sodium chloride diet for a period of 28 days. The hypertensive rats were treated daily with DK extract (50 and 100 mg/kg of body weight; p.o.) or captopril (20 mg/kg of body weight; p.o.), a reference drug, for 14 consecutive days. The blood pressure and heart rate of awake rats were measured using a non-invasive tail-cuff method. The heart weight and left ventricular wall thickness of rats were measured. In vitro angiotensin-converting enzyme (ACE) inhibition activity of the DK extract and captopril were analysed. DK extract significantly and dose-dependently reduced systolic and diastolic blood pressure in the hypertensive rats. There were no significant changes observed in heart rate. The cortisone acetate-induced hypertensive rats had increased heart weight and left ventricular wall thickness. These actions were attenuated by the treatment of DK extract (100 mg/kg) and captopril. Moreover, DK extract inhibited ACE activity in vitro with an IC50 of 4.71±0.53 μg/ml. Our findings demonstrate that DK extract exerted anti-hypertensive effects and alleviated ventricular hypertrophy in the cortisone acetate-induced hypertensive rats and these actions occurred at least in part via ACE activity inhibition.
{"title":"Standardised flavonoid extract from Diospyros kaki L.f leaves alleviates high blood pressure and ventricular hypertrophy on cortisone acetate-induced hypertensive rats","authors":"Thi Thanh Loan Nguyen, Thi Van Anh Pham, Thi Xoan Le","doi":"10.31276/vjste.65(3).80-84","DOIUrl":"https://doi.org/10.31276/vjste.65(3).80-84","url":null,"abstract":"The current study was designed to investigate the anti-hypertensive effects of a standardised flavonoid extract from Diospyros kaki L.f leaves (DK extract) on cortisone acetate-induced hypertensive rats. Hypertension was induced in Wistar rats by subcutaneously injecting 2.5 mg cortisone acetate daily and by maintaining the rats on a 1% sodium chloride diet for a period of 28 days. The hypertensive rats were treated daily with DK extract (50 and 100 mg/kg of body weight; p.o.) or captopril (20 mg/kg of body weight; p.o.), a reference drug, for 14 consecutive days. The blood pressure and heart rate of awake rats were measured using a non-invasive tail-cuff method. The heart weight and left ventricular wall thickness of rats were measured. In vitro angiotensin-converting enzyme (ACE) inhibition activity of the DK extract and captopril were analysed. DK extract significantly and dose-dependently reduced systolic and diastolic blood pressure in the hypertensive rats. There were no significant changes observed in heart rate. The cortisone acetate-induced hypertensive rats had increased heart weight and left ventricular wall thickness. These actions were attenuated by the treatment of DK extract (100 mg/kg) and captopril. Moreover, DK extract inhibited ACE activity in vitro with an IC50 of 4.71±0.53 μg/ml. Our findings demonstrate that DK extract exerted anti-hypertensive effects and alleviated ventricular hypertrophy in the cortisone acetate-induced hypertensive rats and these actions occurred at least in part via ACE activity inhibition.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395887","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}
The authors initially employs the fast Fourier transform (FFT) approach to transforming voice inputs into digital signals before integrating a speech recognition solution (which includes two models: the hidden Markov model (HMM) and the artificial neural network (ANN)). To achieve standard-tone identification of voice signals and digitally store speech, the authors then incorporated a 2048-bit Rivest-Shamir-Adleman (RSA) encryption method to encrypt and decrypt digital speech. The authors’ building team constructed the program using a 256-bit advanced encryption standard - Galois counter mode (AES-GCM) encryption method to assure the application’s effectiveness. The authors successfully created a voice recognition application according to the HMM of ANN. The collected findings suggest that the authors’ secure speech recognition program (named soft voice - RSA) has improved in terms of safety, keeping speech material secret, and speed. It takes roughly 0.2 s to generate a 2048-bit RSA key pair that exceeds the National Institute of Standards and Technology (NIST) standard, 700-1070 ms to process speech, 1-4 ms to encrypt 2048-bit RSA, 6-8 ms to decrypt 2048-bit RSA.
{"title":"Integration of an RSA-2048-bit public key cryptography solution in the development of secure voice recognition processing applications","authors":"Nhu-Quynh Luc, Duc-Huy Quach, Chi-Hung Vu, Hong-Truong Nguyen, Thanh-Long Vo-Khac","doi":"10.31276/vjste.65(3).03-07","DOIUrl":"https://doi.org/10.31276/vjste.65(3).03-07","url":null,"abstract":"The authors initially employs the fast Fourier transform (FFT) approach to transforming voice inputs into digital signals before integrating a speech recognition solution (which includes two models: the hidden Markov model (HMM) and the artificial neural network (ANN)). To achieve standard-tone identification of voice signals and digitally store speech, the authors then incorporated a 2048-bit Rivest-Shamir-Adleman (RSA) encryption method to encrypt and decrypt digital speech. The authors’ building team constructed the program using a 256-bit advanced encryption standard - Galois counter mode (AES-GCM) encryption method to assure the application’s effectiveness. The authors successfully created a voice recognition application according to the HMM of ANN. The collected findings suggest that the authors’ secure speech recognition program (named soft voice - RSA) has improved in terms of safety, keeping speech material secret, and speed. It takes roughly 0.2 s to generate a 2048-bit RSA key pair that exceeds the National Institute of Standards and Technology (NIST) standard, 700-1070 ms to process speech, 1-4 ms to encrypt 2048-bit RSA, 6-8 ms to decrypt 2048-bit RSA.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135397243","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}
A prospective, descriptive study was conducted on 382 pediatric patients diagnosed with pertussis at Vietnam National Children’s Hospital over a two-year period, from January 1st, 2019, to December 31st, 2020. Of all patients participating in this study, children with severe conditions accounted for 30.1% (115/382). Several factors were found to be associated with the risk of this condition with odds ratios (OR) and 95% confidence intervals (CI), including a decrease in the duration of the onset phase by 5 days [OR 1.53, 95% CI: 1.002-2.34], fever [2.49, 1.18-5.24], cyanosis [9.59, 2.9-31.7], pneumonia [14.45, 6.06-34.5], pulmonary hypertension [4.15, 1.02-16.83], an increase of 10 g/l in white blood cell (WBC) count in the full blood count (FBC) test [1.39, 1.05-1.84], a 5-cycle reduction in Cycle threshold (Ct) value in the pertussis real-time PCR test [1.36, 1.01-1.84], and superinfection [3.94, 1.84-8.48 times]. A WBC count in FBC of ≥30 g/l could be used as a prognostic factor for the risk of severe illness condition (sensitivity 46.1%, specificity 90.6%), the requirement for mechanical ventilation (sensitivity 57.1%, specificity 88.5%), and mortality (sensitivity 100%, specificity 91%).
{"title":"Several prognosis factors of severe pertussis in children treated at Vietnam National Children’s Hospital (2019-2020)","authors":"Do Thi Thuy Nga, Nguyen Manh Cuong, Phung Thi Bich Thuy, Tran Minh Dien","doi":"10.31276/vjste.65(3).75-79","DOIUrl":"https://doi.org/10.31276/vjste.65(3).75-79","url":null,"abstract":"A prospective, descriptive study was conducted on 382 pediatric patients diagnosed with pertussis at Vietnam National Children’s Hospital over a two-year period, from January 1st, 2019, to December 31st, 2020. Of all patients participating in this study, children with severe conditions accounted for 30.1% (115/382). Several factors were found to be associated with the risk of this condition with odds ratios (OR) and 95% confidence intervals (CI), including a decrease in the duration of the onset phase by 5 days [OR 1.53, 95% CI: 1.002-2.34], fever [2.49, 1.18-5.24], cyanosis [9.59, 2.9-31.7], pneumonia [14.45, 6.06-34.5], pulmonary hypertension [4.15, 1.02-16.83], an increase of 10 g/l in white blood cell (WBC) count in the full blood count (FBC) test [1.39, 1.05-1.84], a 5-cycle reduction in Cycle threshold (Ct) value in the pertussis real-time PCR test [1.36, 1.01-1.84], and superinfection [3.94, 1.84-8.48 times]. A WBC count in FBC of ≥30 g/l could be used as a prognostic factor for the risk of severe illness condition (sensitivity 46.1%, specificity 90.6%), the requirement for mechanical ventilation (sensitivity 57.1%, specificity 88.5%), and mortality (sensitivity 100%, specificity 91%).","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395892","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 : 2023-09-15DOI: 10.31276/vjste.65(3).59-65
Florieza Mangubat, Cerela Looc, Fretzel Mad
Calcium, obtained from various sources, is essential to fulfil the dietary requirements of birds. Oyster shells are excellent sources of calcium and are widely used in bird diets. Calcium is a critical factor in eggshell deterioration, affecting its absorption. Consequently, this study aimed to determine the combined effects of powdered oyster shell and lemongrass on the growth, development, and egg quality of birds, specifically using 5, 10, and 15 grams of oyster shell powder as a calcium source. A completely randomised design was used to assess the efficacy of varying amounts of powdered oyster shell. Results revealed that there was no significant change in growth development at different inclusion levels of oyster shell powder and lemongrass solution. However, egg quality exhibited a significant variance at different inclusion levels of oyster shell powder. Similarly, lemongrass solution as a supplement for laying quails demonstrated a significant difference. Therefore, supplementing the calcium source with a blend of 15 g of oyster shell powder and 300 ml lemongrass solution enhanced egg performance and eggshell quality of laying quail by 5%.
{"title":"Combined effects of powdered oyster shell (Ostreidae) and lemongrass (Cymbopogon citratus) as a feed additive for growth development of quail (Coturnix coturnixjaponica)","authors":"Florieza Mangubat, Cerela Looc, Fretzel Mad","doi":"10.31276/vjste.65(3).59-65","DOIUrl":"https://doi.org/10.31276/vjste.65(3).59-65","url":null,"abstract":"Calcium, obtained from various sources, is essential to fulfil the dietary requirements of birds. Oyster shells are excellent sources of calcium and are widely used in bird diets. Calcium is a critical factor in eggshell deterioration, affecting its absorption. Consequently, this study aimed to determine the combined effects of powdered oyster shell and lemongrass on the growth, development, and egg quality of birds, specifically using 5, 10, and 15 grams of oyster shell powder as a calcium source. A completely randomised design was used to assess the efficacy of varying amounts of powdered oyster shell. Results revealed that there was no significant change in growth development at different inclusion levels of oyster shell powder and lemongrass solution. However, egg quality exhibited a significant variance at different inclusion levels of oyster shell powder. Similarly, lemongrass solution as a supplement for laying quails demonstrated a significant difference. Therefore, supplementing the calcium source with a blend of 15 g of oyster shell powder and 300 ml lemongrass solution enhanced egg performance and eggshell quality of laying quail by 5%.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395748","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 : 2023-09-15DOI: 10.31276/vjste.65(3).21-26
Trung Thanh Nguyen
This study explored the growth and fermentation capabilities of four distinct yeast strains, including Saccharomyces cerevisiae var. boulardii CNCM I-745, S. cerevisiae 7012, S. cerevisiae 7028, and S. cerevisiae var. diastaticus BE-134, with the aim of identifying the most suitable strain for the production of a fermented beverage from soybean residue hydrolysate (SRH). The results were as follows: S. cerevisiae 7012 exhibited the most efficient fermentation, with residual sugar content of 2.16 g/100 ml, an ethanol concentration of 1.39% v/v, and a favourable aroma, receiving a sensory score of 4.3/5 points. Within this sensory profile, the aromatic compound 2-phenylethanol was found to be the predominant component. Additionally, S. cerevisiae var. boulardii CNCM I-745 demonstrated superior biomass production ability, achieving a cell density of 7.71 log CFU/ml after 48 hours of fermentation solution also showed the highest antioxidant activity, equivalent to 1.63 mg of ascorbic acid per 100 ml. Consequently, these two yeast strains were selected for combined use in fermentation to leverage the probiotic characteristics of S. cerevisiae var. boulardii CNCM I-745 and the flavouring capacity of S. cerevisiae 7012 in creating fermented beverages from SRH.
本研究探讨了4株不同酵母菌的生长和发酵能力，包括酿酒酵母blardii var. CNCM I-745、酿酒酵母S. cerevisiae var. 7012、酿酒酵母S. cerevisiae var. disastaticus BE-134，目的是确定最适合用大豆渣水解物生产发酵饮料的菌株。结果表明:酿酒酵母7012发酵效率最高，残糖含量为2.16 g/100 ml，乙醇浓度为1.39% v/v，香气良好，感官评分为4.3/5分。在这个感官剖面中，芳香族化合物2-苯乙醇被发现是主要成分。此外，酿酒酵母blardii品种CNCM I-745表现出优异的生物质生产能力，发酵液在48小时后达到7.71 log CFU/ml的细胞密度，也显示出最高的抗氧化活性，相当于每100 ml产生1.63 mg抗坏血酸。选择这两种酵母菌菌株进行联合发酵，以利用酿酒葡萄球菌博氏变种CNCM I-745的益生菌特性和酿酒葡萄球菌7012的调味能力，从SRH中生产发酵饮料。
{"title":"Degradation of acrylic-melamine based varnish containing Tinuvin 292 with accelerated exposure in fluorescent UV and condensation","authors":"Trung Thanh Nguyen","doi":"10.31276/vjste.65(3).21-26","DOIUrl":"https://doi.org/10.31276/vjste.65(3).21-26","url":null,"abstract":"This study explored the growth and fermentation capabilities of four distinct yeast strains, including Saccharomyces cerevisiae var. boulardii CNCM I-745, S. cerevisiae 7012, S. cerevisiae 7028, and S. cerevisiae var. diastaticus BE-134, with the aim of identifying the most suitable strain for the production of a fermented beverage from soybean residue hydrolysate (SRH). The results were as follows: S. cerevisiae 7012 exhibited the most efficient fermentation, with residual sugar content of 2.16 g/100 ml, an ethanol concentration of 1.39% v/v, and a favourable aroma, receiving a sensory score of 4.3/5 points. Within this sensory profile, the aromatic compound 2-phenylethanol was found to be the predominant component. Additionally, S. cerevisiae var. boulardii CNCM I-745 demonstrated superior biomass production ability, achieving a cell density of 7.71 log CFU/ml after 48 hours of fermentation solution also showed the highest antioxidant activity, equivalent to 1.63 mg of ascorbic acid per 100 ml. Consequently, these two yeast strains were selected for combined use in fermentation to leverage the probiotic characteristics of S. cerevisiae var. boulardii CNCM I-745 and the flavouring capacity of S. cerevisiae 7012 in creating fermented beverages from SRH.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395393","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 : 2023-09-15DOI: 10.31276/vjste.65(3).32-38
Phan Thi Tuyet Mai, Nguyen Hai Linh, To Phuong Linh, Vu Tien Manh, Ngo Hong Anh Thu, Pham Ngoc Lan, Luu Thi Hue
In this study, cellulose and hemicellulose were successfully extracted from pineapple leaf waste at yields of 58.8 and 16.1% by dried weight, respectively. Carboxymethyl cellulose (CMC) was synthesised from pineapple leaf cellulose by an esterification process using sodium hydroxide (NaOH) and monochloroacetic acid (MCA) with isopropanol as the supporting medium. Preparation of CMC was investigated by varying three free factors, namely, NaOH concentration, MCA dose, and cellulose size. The carboxymethylation process was optimised to produce CMC with differing degrees of substitution (DS). The highest DS of CMC (0.86) was obtained with 15% (w/v) NaOH solution, 0.6 g of MCA/g cellulose, and 50 μm cellulose. The obtained CMC were characterised by FTIR spectroscopy, SEM images and XRD diffractions. Moreover, the thickening performance of obtained CMC was also determined. The influence of the CMC’s molecular weight and degree of substitution on the viscosity of 1% (w/v) aqueous solution was tested. The experimental results suggest that the viscosity of the solution increases with increasing molecular weight and degree of substitution of CMC.
{"title":"Study on synthesis of carboxymethyl cellulose from pineapple leaf waste and its potential applications as a thickener","authors":"Phan Thi Tuyet Mai, Nguyen Hai Linh, To Phuong Linh, Vu Tien Manh, Ngo Hong Anh Thu, Pham Ngoc Lan, Luu Thi Hue","doi":"10.31276/vjste.65(3).32-38","DOIUrl":"https://doi.org/10.31276/vjste.65(3).32-38","url":null,"abstract":"In this study, cellulose and hemicellulose were successfully extracted from pineapple leaf waste at yields of 58.8 and 16.1% by dried weight, respectively. Carboxymethyl cellulose (CMC) was synthesised from pineapple leaf cellulose by an esterification process using sodium hydroxide (NaOH) and monochloroacetic acid (MCA) with isopropanol as the supporting medium. Preparation of CMC was investigated by varying three free factors, namely, NaOH concentration, MCA dose, and cellulose size. The carboxymethylation process was optimised to produce CMC with differing degrees of substitution (DS). The highest DS of CMC (0.86) was obtained with 15% (w/v) NaOH solution, 0.6 g of MCA/g cellulose, and 50 μm cellulose. The obtained CMC were characterised by FTIR spectroscopy, SEM images and XRD diffractions. Moreover, the thickening performance of obtained CMC was also determined. The influence of the CMC’s molecular weight and degree of substitution on the viscosity of 1% (w/v) aqueous solution was tested. The experimental results suggest that the viscosity of the solution increases with increasing molecular weight and degree of substitution of CMC.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"205 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395396","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 : 2023-09-15DOI: 10.31276/vjste.65(3).39-43
Duc Thien Dao, Hoang Sa Nguyen, Huu Thu Do, Thanh Tam Nguyen
Pteris multifida Poir. is an evergreen herbaceous fern that is distributed in temperate and tropical regions of East Asia and cultivated in many other countries. It is an ethnomedicinal plant used for detoxicating, cooling, reducing pain, and as a treatment for many diseases like dysentery, typhoid, cholecystitis, diarrhoea, enteritis, jaundice, and eczema among others. Several compounds including flavonoids, sesquiterpenoids, diterpenoids, coumarins, lignans, and sterols with anti-spasmodic, anti-bacterial, anti-hyperlipidemic, anti-oxidative, and cytotoxic activities have been isolated from this plant. In the present study, three sesquiterpenoids, (2S,3S)-pretosin Q (1), (2R,3S)-pterosin C (2), (2S,3S)-pterosin C (3); two lignans, pinoresinol (4); lariciresinol 9-O-β-glucopyranoside (5), three flavonoids, naringenin (6), apigenin (7), and luteolin (8) were obtained from the ethyl acetate extract of the whole of P. multifida collected in Nam Dinh province, Vietnam. The chemical structures were elucidated by various spectroscopic means including one- and two-dimensional (1D, 2D)-NMR, mass spectrometry, and comparison with published data. Compounds 4-6 were isolated from P. multifida for the first time.
多面体。是一种常绿草本蕨类植物，分布在东亚的温带和热带地区，在许多其他国家都有种植。它是一种民族药用植物，用于解毒、降温、减轻疼痛，并用于治疗许多疾病，如痢疾、伤寒、胆囊炎、腹泻、肠炎、黄疸和湿疹等。从该植物中分离出具有抗痉挛、抗菌、抗高血脂、抗氧化和细胞毒活性的化合物，包括黄酮、倍半萜类、二萜类、香豆素、木脂素和甾醇。在本研究中，三种倍半萜类化合物，(2S,3S)-pretosin Q (1)， (2R,3S)-pterosin C (2)， (2S,3S)-pterosin C (3);两种木脂素，松脂醇(4);从越南南定省采集的多裂藤全株的乙酸乙酯萃取物中分离得到了叶松树脂醇9-O-β-葡萄糖吡喃苷(5)、三种黄酮类化合物柚皮素(6)、芹菜素(7)和木犀草素(8)。通过各种光谱手段，包括一维和二维(1D, 2D) nmr，质谱，以及与已发表数据的比较，对化学结构进行了阐明。化合物4 ~ 6为首次从该植物中分离得到。
{"title":"Compounds from the ethyl acetate extract of Pteris multifida Poir. collected in Nam Dinh province, Vietnam","authors":"Duc Thien Dao, Hoang Sa Nguyen, Huu Thu Do, Thanh Tam Nguyen","doi":"10.31276/vjste.65(3).39-43","DOIUrl":"https://doi.org/10.31276/vjste.65(3).39-43","url":null,"abstract":"Pteris multifida Poir. is an evergreen herbaceous fern that is distributed in temperate and tropical regions of East Asia and cultivated in many other countries. It is an ethnomedicinal plant used for detoxicating, cooling, reducing pain, and as a treatment for many diseases like dysentery, typhoid, cholecystitis, diarrhoea, enteritis, jaundice, and eczema among others. Several compounds including flavonoids, sesquiterpenoids, diterpenoids, coumarins, lignans, and sterols with anti-spasmodic, anti-bacterial, anti-hyperlipidemic, anti-oxidative, and cytotoxic activities have been isolated from this plant. In the present study, three sesquiterpenoids, (2S,3S)-pretosin Q (1), (2R,3S)-pterosin C (2), (2S,3S)-pterosin C (3); two lignans, pinoresinol (4); lariciresinol 9-O-β-glucopyranoside (5), three flavonoids, naringenin (6), apigenin (7), and luteolin (8) were obtained from the ethyl acetate extract of the whole of P. multifida collected in Nam Dinh province, Vietnam. The chemical structures were elucidated by various spectroscopic means including one- and two-dimensional (1D, 2D)-NMR, mass spectrometry, and comparison with published data. Compounds 4-6 were isolated from P. multifida for the first time.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395586","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 : 2023-09-15DOI: 10.31276/vjste.65(3).27-31
Tien Dat Doan, Nhung Hac Thi, Ho Thi Oanh, Tuyen Nguyen Duc, Dong Hoon Choi, Mai Ha Hoang
Transparent flexible electrodes based on silver nanowires (AgNWs) have great potential for practical applications and many studies have been carried out to improve their conductivity, transparency, and surface roughness. In this study, we demonstrate a new approach for the fabrication of high-performance transparent flexible electrodes based on AgNWs and graphene oxide (GO) on polymer substrates using the pressing method. The surface morphology of the pressed AgNW/GO electrode was characterised by atomic force microscopy (AFM) and observed by scanning electron microscope (SEM). The electrode had a low surface roughness with the root mean square (Rq) of 7 nm. The electrode exhibits a low sheet resistance of 22 Ω/sq, a high transmittance of ~88%, resulted in a figures-of-merit (FoM) value of ~12.6. The optical and electrical properties of the electrode are comparable to that of the flexible ITO electrode. In addition, the electrodes also displayed outstanding durability and mechanical stability. This simple and scalable fabrication method is expected to contribute to future studies on flexible transparent conductive electrodes.
{"title":"Fabrication of transparent flexible electrodes on polyethylene terephthalate substrate with high conductivity, high transmittance, and excellent stability","authors":"Tien Dat Doan, Nhung Hac Thi, Ho Thi Oanh, Tuyen Nguyen Duc, Dong Hoon Choi, Mai Ha Hoang","doi":"10.31276/vjste.65(3).27-31","DOIUrl":"https://doi.org/10.31276/vjste.65(3).27-31","url":null,"abstract":"Transparent flexible electrodes based on silver nanowires (AgNWs) have great potential for practical applications and many studies have been carried out to improve their conductivity, transparency, and surface roughness. In this study, we demonstrate a new approach for the fabrication of high-performance transparent flexible electrodes based on AgNWs and graphene oxide (GO) on polymer substrates using the pressing method. The surface morphology of the pressed AgNW/GO electrode was characterised by atomic force microscopy (AFM) and observed by scanning electron microscope (SEM). The electrode had a low surface roughness with the root mean square (Rq) of 7 nm. The electrode exhibits a low sheet resistance of 22 Ω/sq, a high transmittance of ~88%, resulted in a figures-of-merit (FoM) value of ~12.6. The optical and electrical properties of the electrode are comparable to that of the flexible ITO electrode. In addition, the electrodes also displayed outstanding durability and mechanical stability. This simple and scalable fabrication method is expected to contribute to future studies on flexible transparent conductive electrodes.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395583","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 : 2023-09-15DOI: 10.31276/vjste.65(3).44-49
Thi Hai Yen Pham, Thi Kim Ngan Nguyen, Thi Thu Hien Chu, Thi Thu Ha Vu, Quoc Hung Le
This study investigates the modification of pencil lead graphite electrodes with polyglutamic acid using an effective and fast static method to develop a sensor for the detection of enrofloxacin (ENR). The successful fabrication of pGA on the electrode surface was confirmed by scanning electron microscopy, energy dispersive X-ray analysis, and Fourier-transform infrared spectroscopy. The conditions of electrochemical modification, including the applied potentials and number of cycles in the potentiostatic process, were systematically investigated to determine their effects on the ENR electrochemical response. The pH of the electrolyte media was also explored to elucidate the electrochemical reaction mechanism of ENR. The developed electrochemical sensor was evaluated using square wave stripping voltammetry for ENR detection. Under optimal conditions, the sensor demonstrated good reproducibility with a relative standard deviation of 4.3% (from five measurements) for ENR signal detection. A linear relationship between ENR concentration and its peak current was observed in the concentration range of 0.1 to 5 μM, with a high correlation coefficient of 0.9988. The limit of detection for ENR using the sensor was 0.12 μM. Our findings provide valuable insights into the design and optimisation of pencil lead graphite electrode-based sensors for ENR detection in aqueous media.
{"title":"Pencil lead graphite electrochemically modified with polyglutamic acid as a sensor for detection of enrofloxacin in aqueous media","authors":"Thi Hai Yen Pham, Thi Kim Ngan Nguyen, Thi Thu Hien Chu, Thi Thu Ha Vu, Quoc Hung Le","doi":"10.31276/vjste.65(3).44-49","DOIUrl":"https://doi.org/10.31276/vjste.65(3).44-49","url":null,"abstract":"This study investigates the modification of pencil lead graphite electrodes with polyglutamic acid using an effective and fast static method to develop a sensor for the detection of enrofloxacin (ENR). The successful fabrication of pGA on the electrode surface was confirmed by scanning electron microscopy, energy dispersive X-ray analysis, and Fourier-transform infrared spectroscopy. The conditions of electrochemical modification, including the applied potentials and number of cycles in the potentiostatic process, were systematically investigated to determine their effects on the ENR electrochemical response. The pH of the electrolyte media was also explored to elucidate the electrochemical reaction mechanism of ENR. The developed electrochemical sensor was evaluated using square wave stripping voltammetry for ENR detection. Under optimal conditions, the sensor demonstrated good reproducibility with a relative standard deviation of 4.3% (from five measurements) for ENR signal detection. A linear relationship between ENR concentration and its peak current was observed in the concentration range of 0.1 to 5 μM, with a high correlation coefficient of 0.9988. The limit of detection for ENR using the sensor was 0.12 μM. Our findings provide valuable insights into the design and optimisation of pencil lead graphite electrode-based sensors for ENR detection in aqueous media.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"241 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135395742","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：