Extractive spectrophotometric methods for determination of ciprofloxacin in pharmaceutical formulations using sulfonephthalein acid dyes

Three simple, rapid, sensitive and accurate extractive-spectrophotometric method for the determination of ciprofloxacin in pharmaceutical preparation has been developed. These methods are based on the formation of yellow ion-pair complexes between the examined drug and three sulfonephthalein  acid dyes, namely; bromophenol blue (BPB), bromocresol green (BCG),  and bromothymol blue (BTB) in  acidic medium. The formed complexes were extracted with chloroform and measured at 420, the colored chromogen was stable for twenty four hours. The effect of optimum conditions via pH, dye concentration, time and solvent are studied. Beer’s law is obeyed in the concentration ranges 0.50-25.0 μg/mL with  molar absorptivity of 1.46´104, 1.83´104 and 2.07´104 L. mol-1. cm-1 and limit of detection (LOD) of 0.105, 0.101, 0.084 for BPB, BCG and BTB methods, respectively. No interference was observed from common excipients present in pharmaceutical formulations. The proposed method has been applied successfully to determine ciprofloxacin in pharmaceutical preparation (tablets, infusion and eye drops). Keywords. Ciprofloxacin, extraction-spectrophotometry, ion pair complex; sulfonephthalein  dyes

The use of Vietnamese in English phonology classes: Voices from tertiary teachers and students

Using the mother tongue (L1) to improve four English language skills, namely listening, reading, writing, and speaking for English as a Foreign Language (EFL) students, and to enhance their understanding and learning process has been investigated throughout the years. However, very few studies focus on the context of Vietnamese as the L1 in a course related to English language components such as an English phonology course. Therefore, this research focuses on the use of Vietnamese by lecturers and students in this course. Specifically, the study explores teachers’ and students’ perceptions of using Vietnamese and how they used it in these courses. A five-point Likert scale questionnaire was distributed to 238 students majoring in English language studies at one of the universities in Vietnam to determine their perception and practice. Meanwhile, semi-structured interviews were also conducted with five lecturers of an English phonology course. The data from the questionnaire was analyzed descriptively and thematic analysis was used to analyze the responses from the interviews. The findings revealed that all the lecturers and students used Vietnamese primarily for academic purposes, strongly supporting its use in an English Phonology class. The results also showed that L1 played an important role in learning and teaching. In addition, students showed considerably positive attitudes towards the use of Vietnamese in this classroom context. The study provides some suggestions to enhance the use of L1 in classes related to English language components, and recommendations for future research

Optimal design parameters of air suspension systems for semi-trailer truck. Part 2: results and discussion

Based on the results of model and algorithm in Part1 for searching the optimal design parameters of vehicle suspensions using genetic algorithm, in Part 2, the simulation results with MATLAB Simulink combined with an optimal program are written to search the optimal design parameters of vehicle air suspension systems in two optimal conditions. The optimal results indicate that the DLC values at all axles of vehicle respectively reduce by 9.09 %, 10.71 %, 11.11%, 10.81 %, 8.82 % (in Case 1) and 14.29 %, 19.23 %, 20.00 %, 17.14 %, 12.12 % (in Case 2) in comparison with the original air suspension systems when vehicle moves on the ISO class C road surface at v= 20 m/s and full load. All these things indicate that using the genetic algorithm optimization method does not only reduce the tire dynamic loads acting on road surface but also improves the ride comfort. Finally, the optimum performance of vehicle suspension systems is considered and reassessed under different operating conditions. The evaluation results indicate that the optimum performance of the air suspension systems has better potential to improve the road friendliness which provides a ride comfort for road surfaces and vehicle

Optimal design parameters of air suspension systems for semi-trailer truck. Part 1: modeling and algorithm

The purpose of this paper is to improve the performance of air suspension systems for a semi-trailer truck in the direction of reducing the dynamic wheel load acting on road surface (Part 1: modeling and algorithm). To achieve the goal of finding the optimal design parameters for the air suspension systems, a half-vehicle dynamic model under the road-vehicle interaction with 12 degrees of freedom (d.o.f) is established for searching the optimal design parameters of vehicle suspensions using genetic algorithm (GA). Dynamic load coefficient (DLC) is considered as a target function. Two optimal conditions: optimal design of geometrical parameters of air spring suspension systems (Case 1) and optimal design of parameters of air suspension systems (Case 2) are selected in this study. The results of this paper are the basis for optimization and discussion in Part 2 as the results and discussion

THÀNH PHẦN LOÀI KHU HỆ CÁ VÙNG BIỂN VEN BỜ TỈNH QUẢNG NGÃI

Three surveys were carried out in May, August and December 2014 at 7 sampling location to determine species composition of fish fauna in the coastal waters of Quang Ngai province (the Central Vietnam). A total number of 178 species of fishes were identified belonging to 125 genera, 68 families and 13 orders. Analysis of community structure of fish fauna showed that Perciformes order was the most popular, making up 71.9%; Tetraodontiformes (8.4%); Pleuronectiformes (5.6%). Serranidae family was the most abundant with 14 species, making up 7.9% of the total number of species; Carangidae: 12 species (6.7%); Lutjanidae, Gobiidae had the same number of species with 9 species (5.1%); Scombridae: 7 species (3.9%); Soleidae: 6 species (3.4%); Haemulidae, Mullidae, Tetraodontidae: 5 species (2.8%);... Cluster analysing based on the Bray-Curtis similarity index of nine fish faunas (Thai Binh, Son Tra, Thu Bon, Quang Nam, Nha Phu-Binh Cang, Ben Tre and Tra Vinh) showed that fish composition of the coastal estuaries of Tra Vinh and Ben Tre had the highest similarity (80%), subsequently fish fauna of Quang Ngai had similarity with that of Nha Phu-Binh Cang (39%), Quang Ngai and Quang Nam (42%), Quang Nam and Nha Phu-Binh Cang (41%), Quang Nam and Son Tra (38%), Thai Binh and Ben Tre (37%), Quang Ngai and Son Tra (36%). The result was also classified into two distinct groups of 7 fish faunas: Group 1-Tra Vinh, Ben Tre and Thai Binh; group 2-Quang Ngai, Quang Nam, Nha Phu-Binh Cang and Son Tra. The species richness (Margalef’s index) of Quang Ngai (34.2) was less abundant than other areas, the highest species richness belonged to Tra Vinh (38.2), Thai Binh (38.0), Quang Nam (37.8), Nha Phu-Binh Cang (35.1), Son Tra (30.9), Ben Tre (29.4). The diversity of species composition according to the level taxa in each region showed the characteristic of each fish fauna.Thực hiện 3 chuyến khảo sát thu mẫu thành phần loài cá vùng biển ven bờ tỉnh Quảng Ngãi trong năm 2014 tại 7 điểm thu mẫu. Kết quả đã ghi nhận được 178 loài thuộc 13 bộ, 68 họ và 125 giống. Phân tích cấu trúc quần xã khu hệ cá cho thấy: Bộ cá vược Perciformes là bộ cá phổ biến nhất chiếm 71,9%; tiếp đến là bộ cá nóc 8,4%; bộ cá bơn 5,6%; các bộ còn lại mỗi bộ có số loài, giống và họ rất ít. Các họ chiếm ưu thế về loài: Họ cá mú (Serranidae) 14 loài chiếm 7,9% tổng số loài; cá khế (Carangidae) 12 loài (6,7%); cá hồng (Lutjanidae), cá bống trắng (Gobiidae) 9 loài (5,1%); cá thu ngừ (Scombridae) 7 loài (3,9%); cá bơn sọc (Solidae) 6 loài (3,4%); cá sạo (Haemulidae), cá phèn (Mullidae), cá nóc (Tetraodontidae) 5 loài (2,8%);... So sánh với 6 khu hệ cá cửa sông vùng biển ven bờ của Việt Nam (Thái Bình, Sơn Trà, Quảng Nam, Nha Phu-Bình Cang, Bến Tre và Trà Vinh) ghi nhận, vùng ven biển cửa sông Trà Vinh và Bến Tre có mức tương đồng cao nhất 80%; tiếp đến là Quảng Ngãi và Nha Phu-Bình Cang 39%; Quảng Ngãi và Quảng Nam 42%; Quảng Nam và Nha Phu-Bình Cang 41%; Thái Bình và Bến Tre 37%; Quảng Nam và Sơn Trà 38%; Quảng Ngãi và Sơn Trà 36%. Phân tích nhóm cho thấy thành phần loài thuộc 7 khu hệ cá hình thành nên 2 nhóm: Nhóm 1: Trà Vinh, Bến Tre và Thái Bình; nhóm 2: Quảng Ngãi, Quảng Nam, Nha Phu-Bình Cang và Sơn Trà. Độ giàu có về loài của Quảng Ngãi đạt (34,2), Trà Vinh cao nhất (38,2), tiếp đến Thái Bình (38,0), Quảng Nam (37,9), Nha Phu-Bình Cang (35,1), Sơn Trà (30,9), Bến Tre (29,4). Tính đa đạng về thành phần loài cá theo các bậc taxon trên từng vùng thể hiện tính đặc trưng riêng cho từng khu hệ

A new record of congrid eel, Bathycongrus bleekeri (Congridae) from Vietnam

Three specimens of Bathycongrus bleekeri were collected during the survey in 2015 and 2017. The newly recorded species is described herein, a small, moderately elongate species of Bathycongrus with head and body compressed; vertical fins without black mark; tail slender, attenuated, but not filiform; trunk length 1.2 times greater than head length; teeth small, conical, in about three-four rows on jaws, in a small triangular patch on vomer; 28–29 preanal vertebrae, total of 111–113 vertebrae; 26–28 preanal lateral-line pores. Additional data on the morphology and distribution of the species increases the total number of known species in the family Congridae in Vietnamese waters to twelve

ĐẶC ĐIỂM PROTEASE NGOẠI BÀO TỪ CHỦNG Bacillus tequilensis ON1

A bacterial strain with casein hydrolytic activity was isolated from shrimp waste sludge from a culture pond at Phong Dien, Thua Thien Hue. Molecular identification using 16S rRNA nucleotide sequence shows a high similarity to Bacillus tequilensis on the NCBI database. Hence, the isolate was named B. tequilensis ON1. Extracellular protease activity value is 192,42 U·mL–1 after 24 h culture. Zymogram SDS-PAGE electrophoresis shows that the major extracellular protease has a molecular weight of 130 kDa. The enzyme exhibits maximal activity at 50 °C and pH 8. Protease activity increases in the presence of Ca2+ and Mg2+ ions, while Mn2+ inhibits protease activity. The protease activity was more active and stable in hydrophobic organic solvents.Từ mẫu bùn thải của ao nuôi tôm tại huyện Phong Điền, tỉnh Thừa Thiên Huế, chúng tôi đã phân lập được chủng vi khuẩn phân giải casein. Định danh phân tử thông qua giải trình tự 16S rRNA và so sánh với cơ sở dữ liệu GenBank cho thấy chủng phân lập tương đồng cao với vi khuẩn Bacillus tequilensis và được đặt tên là B. tequilensis ON1. Hoạt tính protease ngoại bào đạt giá trị cao nhất 192,42 U·mL–1 sau 24 giờ nuôi cấy. Điện di SDS-PAGE trên nền cơ chất cho thấy protease ngoại bào chính của chủng ON1 có khối lượng phân tử khoảng 130 kDa. Enzyme ngoại bào hoạt động tối ưu ở 50 °C và pH 8. Hoạt tính protease tăng lên khi có mặt Ca2+ và Mg2+, trong khi đó Mn2+ ức chế hoạt động của protease. Protease hoạt động và ổn định hơn trong các dung môi hữu cơ kỵ nước

Assessment of Antioxidant and Antibacterial Activities of Lactobacillus farciminis HN11 as a Probiotic Candidate

Background and Objective: Lactobacillus farciminis is an obligate homofermentative bacterial species in fermented foods. Although other species such as Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus rhamnosus in Lactobacillus genus have been well characterized, probiotic characteristics of Lactobacillus farciminis still need to investigate. Thus, the objective of this study was to investigate probiotic characteristics and antibacterial activity of Lactobacillus farciminis HN11 isolated from Solanum macrocarpon sauces in Hue city, Vietnam. Material and Methods: Lactobacillus farciminis HN11 was cultured in Rogosa and Sharpe media and antibacterial activity of the free-cell suspension was assessed against Escherichia coli, Vibrio parahaemolyticus K5, Vibrio parahaemolyticus KS-02, Vibrio owensii KS-05, Vibrio alginolyticus KS-08, Vibrio alginolyticus A1-1 and Staphylococcus aureus using agar well diffusion method. Various probiotic characteristics of the isolate including antibacterial and antioxidant activities, autoaggregation and coaggregation were assessed. Furthermore, hemolytic and amino-acid dercarboxylase activities were assessed for biosafety assessment. The strain abilities to resist sodium chloride and bile salts were assessed as well. Results and Conclusion: Lactobacillus farciminis HN11 exhibited significant resistance to NaCl and bile salts. The strain expressed high coaggregation abilities for Escherichia coli, significant autoaggregation abilities and antibacterial activities against Vibrio spp. and Escherichia coli. Antioxidant assessment showed that Lactobacillus farciminis HN11 contained high antioxidant activities. This strain was negative for hemolytic and amino-acid dercarboxylase activities. Moreover, ampicillin and chloramphenicol inhibited growth of Lactobacillus farciminis HN11. This study assessed characteristics of Lactobacillus farciminis HN11 and showed its great potentials as a probiotic in fermented foods, enhancing antioxidant and decreasing harmful foodborne bacteria. Although, encapsulation of the strain within acid resistance materials is suggested to better protect it against high-acid contents of the stomach. Conflict of interest: The authors declare no conflict of interest

KẾT QUẢ BƯỚC ĐẦU NGHIÊN CỨU KHU HỆ CÁ CỬA SÔNG THU BỒN, TỈNH QUANG NAM

This report presents the result of four surveys in 2013 at 12 sampling stations on fish composition of fish fauna in the Thu Bon estuary of Quang Nam province (the central Vietnam) and a total of 139 species of fishes were identified belonging to 110 genera, 63 families and 17 orders. Analysis of community structure of fish fauna showed that the order Perciformes was the most popular, making up 56.1%; Cypriniformes (8.6%); Pleuronectiformes (6.5%); Clupeiformes and Siluriformes (4.3%); Anguilliformes, Tetraodontiformes (3.6%); Mugiliformes (2.9%); ... The family Gobiidae was the most abundant with 12 species, making up 8.6% of the total number of species; Cyprinidae (10 species, 7.2%); Leiognathidae, Carangidae had the same number of species (6 species, 4.3%); Clupeidae, Lutjanidae: 5 species (3.6%); Serranidae, Mugilidae, Soleidae, Gerreidae, Ambassidae, Tetraodontidae: 4 species (2.9%); In addition, 4 families had 3 species, 12 families had 2 species and 35 families had 1 species. Cluster analysis based on the Bray - Curtis similarity index of nine fish faunas (Bach Dang, Thai Binh, Bu Lu, Son Tra peninsula, Thu Bon, coastal wetlands of Quang Nam, Nha Phu - Binh Cang, Ben Tre and Tra Vinh) showed that fish composition of the coastal - estuaries of Tra Vinh and Ben Tre had the highest similarity (78%), subsequently fish faunas of Thu Bon had similarity with that of Quang Nam (47%), Quang Nam and Nha Phu - Binh Cang (41%), Bu Lu and Thu Bon (38%). The result was also classified into three distinct groups of 9 fish faunas: group 1- Tra Vinh, Ben Tre and Thai Binh; group 2- Quang Nam, Thu Bon, Nha Phu - Binh Cang, Son Tra and Bu Lu; group 3- Bach Đang. The species richness (Margalef’s index) of Thu Bon (28.0) was less abundant than that of other areas: the highest species richness belonging to Tra Vinh (39.4), Thai Binh (38.6), Nha Phu - Binh Cang (35.9), Son Tra (31.8), Bu Lu (29.7), … The diversity of species composition according to the taxa in each region showed the characteristic of each fish fauna. The fish fauna is evidently typical of characteristics of the estuarine waters and coastal lagoons. There are 4 threatened species which are listed in the Vietnam’s Red Data Book (2007) at ex-tremely vulnerable levels.Thực hiện 4 chuyến khảo sát thu mẫu thành phần loài cá vùng cửa sông Thu Bồn trong năm 2013 tại 12 điểm thu mẫu. Kết quả đã ghi nhận được 139 loài thuộc 17 bộ, 63 họ và 110 giống. Phân tích cấu trúc quần xã khu hệ cá cho thấy: bộ cá Vược Perciformes là bộ cá phổ biến nhất chiếm 56,1%; tiếp đến là bộ cá Chép 8,6%; bộ cá Bơn Pleuronectiformes chiếm 6,5%; bộ cá Trích Clupeiformes và cá Nheo Siluriformes mỗi bộ 4,3%; bộ cá Chình Anguilliformes, cá Nóc Tetraodontiformes (3,6%); bộ cá Đối Mugiliformes (2,9%); ... Các họ chiếm ưu thế về loài: họ cá Bống trắng (Gobiidae) 12 loài chiếm 8,6% tổng số loài; cá Chép (Cyprinidae) 7,2%; cá Liệt (Leiognathidae) và cá Khế (Carangidae) mỗi họ 4,3%; cá Trích (Clupeidae), cá Hồng (Lutjanidae): 3,6%, ... So sánh với 8 khu hệ cá cửa sông - ven biển Việt Nam (Bạch Đằng, Thái Bình, Bù Lu, Sơn Trà, vùng đất ngập nước ven biển tỉnh Quảng Nam, Nha Phu - Bình Cang, Bến Tre và Trà Vinh) ghi nhận, vùng ven biển cửa sông Trà Vinh và Bến Tre có mức tương đồng cao nhất 78%, tiếp đến là Quảng Nam và Thu Bồn 47%, Quảng Nam và Nha Phu - Bình Cang 41%, Bu Lu và Thu Bồn 38%. Phân tích chỉ số giống nhau về thành phần loài của 9 khu hệ cá hình thành nên 3 nhóm: nhóm 1: Trà Vinh, Bến Tre và Thái Bình; nhóm 2: Quảng Nam, Thu Bồn, Nha Phu - Bình Cang, Sơn Trà và Bù Lu; Bạch Đằng hình thành riêng nhóm 3. Độ giàu có về loài của Thu Bồn đạt 28,0; Trà Vinh đạt cao nhất 39,4; tiếp đến là Thái Bình (38,6); Nha Phu - Bình Cang (35,9), Sơn Trà (31,8), Bù Lu (29,7), … Tính đa đạng về thành phần loài cá theo các bậc taxon trên từng vùng thể hiện tính đặc trưng riêng cho từng khu hệ. Các khu hệ cá thể hiện rõ tính chất nước lợ điển hình của các thuỷ vực cửa sông, đầm phá ven biển. Có 4 loài cá quý hiếm được ghi trong sách đỏ Việt Nam 2007 ở mức độ rất nguy cấp

A modern purification by accelerated solvent extraction and centrifugal partition chromatography and biological evaluation of capsaicin from Capsicum chinense

A special alkaloid compound known as capsaicin, which can only be found in the fruit of the Capsicum plant, was isolated and tested for its anti-inflammatory activity. The purpose of this work is to establish a simple and quick approach for capsaicin purification utilizing centrifugal partition chromatography (CPC) as well as an effective method - accelerated solvent extraction (ASE), for extracting capsaicin from Capsicum chinense. After purification, capsaicin was validated by HPLC-DAD at 281 nm to be > 90% purity. The in vivo anti-inflammatory activity of the isolated capsaicin was also investigated, and the IC50 value of the capsaicin was determined to be 57.61 µg/mL. The current work emphasizes how an ASE and CPC system may combine to extract high-purity capsaicin from Capsicum chinense, which have the anti-inflammatory activity, as we evaluated in the experiment