Formulation and in vivo imaging evaluation of colonic targeting tablets prepared by a simple dry powder coating technique

Tung Nguyen-Thach,Nguyen Canh-Hung,Nguyen Van-Duong,Nguyen Thi-Hong-Thuy,Nguyen Van-Lam,Tran Cao-Son,Pham Thi-Minh-Hue 한국약제학회 2020 Journal of Pharmaceutical Investigation Vol.50 No.4

Purpose The study aimed firstly to determine the release behavior of the model drug (berberine chloride) from the dry coated tablets. The second objective of this study was to evaluate the exact location of the dry coated tablets in in vivo. Methods The colon targeting tablets were developed by dry powder coating technique on pan coater. The drug release behavior was determined in the three continuous mediums: pH 1.2; 7.4 and 6.8 plus pectinase. The location of the dry coated tablets in the gastrointestinal tract of human volunteers was observed through the X-ray imaging of the dry coated tablets containing the optimized radiocontrast agents. Results The release kinetics of berberine chloride from the dry coated tablets was mainly controlled by erosion and enzyme sensitive mechanism. The optimum dry coated tablets having the coating powders of pectin 102:HPMC K4 M (2:1) with the coating level of 200%, and the tablet core with BaSO4 10% and iobitridol 30% as radiocontrast agents were observed in the caecum and ascending colon of human volunteers after 5–6 h of oral administration. Conclusion The successful development of these dosage forms is believed to have a high potential in precisely monitoring the release of highly potent drugs such as anti-inflammatory drugs in bowel diseases.

Strut-and-tie model for shear capacity of corroded reinforced concrete columns

Tran, Cao Thanh Ngoc,Nguyen, Xuan Huy,Nguyen, Huy Cuong,Vu, Ngoc Son Techno-Press 2020 Advances in concrete construction Vol.10 No.3

An analytical model is developed in this paper to predict the shear capacity of reinforced concrete (RC) columns with corroded transverse reinforcements. The shear strength model for corroded RC columns is proposed based on modifying the existing strut-and-tie model, which considers the deformational compatibility between truss and arch mechanisms. The contributions to the shear strength from both truss and arch mechanisms are incorporated in the proposed model. The effects of corrosion level of transverse reinforcements are considered in the proposed model through the minimum residual cross-sectional area of transverse reinforcements and the reduction of concrete compressive strength for the cover area. The shear strengths calculated from the developed model are compared with the experimental results from Vu's study (2017), which consisted of RC columns with corroded transverse reinforcements showing shear failure under the cyclic loading. The comparison results indicate satisfactory correlations. Parametric studies are conducted based on the developed shear strength model to explore the effects of column axial loading, aspect ratios, transverse reinforcements and the corrosion levels in transverse reinforcements to the shear strength of RC columns with corroded transverse reinforcements.

Preparation of Silver Core-Chitosan Shell Nanoparticles Using Catechol-Functionalized Chitosan and Antibacterial Studies

Thanh Son Cu,Ngoc Quyen Tran,Van Du Cao,Cuu Khoa Nguyen 한국고분자학회 2014 Macromolecular Research Vol.22 No.4

In this paper, we report the preparation and stabilization of colloidal silver nanoparticle solution, with theassistance of chitosan dihydroxyphenyl acetamide (CDHPA), or oligochitosan dihydroxyphenyl acetamide (OCDHPA). The structure of the chitosan derivatives were characterized by nuclear magnetic resonance (1H NMR) spectroscopy. The morphology of the synthesized silver core-chitosan shell nanoparticles were observed by transmission electronmicroscopy (TEM) and X-ray diffraction (XRD) techniques, and showed a well-defined core-shell structure of polymer-coated silver nanoparticles (AgNPs). The core-shell NPs exhibited a strong antibacterial activity against E. coliand S. aureus, at a very low concentration of AgNPs (2.5 ppm). Our studies offer a new method for the preparationand protection of silver nanoparticles for antibacterial applications.

Control of morphology and Orientation of Electrochemically Grown ZnO Nanorods

Tran Hoang Cao Son,Le Khac Top,Nguyen Thi Dong Tri,Ha Thuc Chi Nhan,Lam Quang Vinh,Bach Thang Phan,김상섭,Le Van Hieu 대한금속·재료학회 2014 METALS AND MATERIALS International Vol.20 No.2

We report the direct electrochemical deposition of ZnO nanorods on an indium tin oxide substrate. Themorphology and orientation of the grown ZnO nanorods were investigated as functions of the currentdensity. It is likely that the concentrations of OH- and Zn2+ ions, which could be controlled by varying thecurrent density, determine the shape and alignment of the ZnO nanorods. The nanorods were tilted, hexagonal,and prismatic at a low current density (0.1 mA/cm2) and vertically aligned and obelisk-shaped at highcurrent densities (greater than 0.6 mA/cm2). By using the low and high current densities sequentially in atwo-step growth process, vertically aligned, hexagonal, and prismatic ZnO nanorods could be grownsuccessfully. The underlying mechanism responsible for the growth of the ZnO nanorods is also discussed.

Complete genome sequence of a highly effective diazotroph Ensifer sesbaniae SDT23 isolated from soybean root nodules in Vietnam

Thi Hieu Thu Nguyen,Thuy Hang Dinh,Cao Son Trinh 한국미생물학회 2022 미생물학회지 Vol.58 No.3

The diazotroph Ensifer sesbaniae SDT23 was isolated from root nodules of healthy soybean plants in the Hanoi countryside. The strain possesses several agricultural beneficial characteristics, i.e. fixing nitrogen, producing Indole-3-acetic acid (IAA) and Extracellular polysaccharides (EPS), and thus has good potential in the application for organic agriculture and soil amendment. Here we show the draft genome sequence of strain SDT23 which is composed of 6,870,960 bp. with a GC content of 62.11% and approximately 6427 protein-coding sequences. The genome annotation indicated nitrogen fixationand nodulation-related genes, along with genes involved in IAA, siderophore, and EPS biosynthesis, confirming the physiological properties of the strain.

복합재 튜브를 이용한 고속 열차의 에너지 흡수장치에 대한 실험 및 수치해석 연구

장홍규 ( Hong Kyu Jang ),신재환 ( Jae Hwan Shin ),손유나 ( Yu Na Shin ),김천곤 ( Chun Gon Kim ),( Cao Son Nguyen ) 한국복합재료학회 2011 Composites research Vol.24 No.1

본 논문에서는 복합재료 튜브를 이용한 고속 열차의 에너지 흡수장치에 대한 실험 및 수치 해석에 관한 연구를 수행하였다. 논문의 목적은 에너지 흡수장치에 대한 최적의 적층(lay-up) 형태를 알아내는 것으로, quasi static method를 이용한 네 가지 적층 형태에 대한 실험을 수행 하였다: [0/45/90/-45]4, [0]16, [0/90]8, [0/30/-30]5. 실험을 위해 초기 파괴 시작점을 생성하고, 일정 방향으로 진행되는 파괴를 만들기 위해 베벨 엣지(bevel edge)와 노치 엣지(notch edge)의 두 가지 트리거링 방법을 이용하였다. 저속 충돌실험 결과 [0/45/90/-45]4의 적층 형태가 다른 방법과 비교해서 가장 좋은 에너지 흡수 결과를 보여주었다. 수치해석을 위해 LS-DYNA 프로그램의 변수 분석(parametric analysis)을 통해 가장 적합한 복합재료의 quasi static 실험 시뮬레이션 방법 연구를 수행하였다. 움직이는 벽이 복합재 튜브에 저속 충돌하는 모델을 가정하여 해석을 수행하였으며, 실험값과 수치해석 결과의 비교를 통해 비슷한 경향을 보임을 확인 하였다. 특히 TFAIL과 mass scaling factor를 조절하며 수행하는 변수 분석은 LS-DYNA에서 복합재 튜브의 quasi static 실험을 시뮬레이션 하는 능력과 한계를 보여준다. This paper presents an experimental and numerical study on composite tubes for the energy absorber of the high-speed train. The purpose of the experimental study is to find out which lay-up is the best lay-up for the energy absorber. Four lay-ups were tested using quasi static method: [0/45/90/-45]4, [0]16, [0/90]8, [0/30/-30]5. Two triggering methods were used to create initial damage and guarantee the progressive collapse mode: bevel edge and notch edge. As a result, [0/45/90/-45]4 lay-up was find out the best lay-up among the laminates being tested. In the numerical study, a parametric analysis was done to find out the most proper way to simulate the quasi static test of a composite tube using LS-DYNA program. A single composite tube was modeled to be crashed by a moving wall. Comparison between simulation and experiment was done. Reasonable agreement between experiment and analysis was obtained. Dealing with parameter TFAIL and the mass scaling factor, this parametric study shows the ability and the limitation of LS-DYNA in modeling the quasi static test for the composite tube.