Isolation, Characterization, and Biological Activities of Fucoidan Derived from Ceratophyllum Submersum L.

Ngoc Nhon Hoang,Tri Khoi Nguyen,Tuyet Hoa Vo,Ngoc Hoi Nguyen,Dai Hai Nguyen,Dieu Linh Tran 한국고분자학회 2022 Macromolecular Research Vol.30 No.2

Fucoidan, a natural sulfated polysaccharide extracted from seaweed, has been widely used in pharmaceutical field due to its excellent biological activities including antiviral, anticancer, antioxidant, anticoagulant, etc. Therefore, investigating the new natural sources of fucoidan has been received growing attention recently. This study reported for the first time the isolation, purification, characterization, and biological activities of fucoidan from Ceratophyllum submersum (FCS). The molecular weight of obtained FCS was 9.7 kDa, composed of fucose (42.11%) and sulfate (16.38%). The FCS contained (1→3)-α-L-Fucopyranose and β-D-galactose bond in the structure. In addition, FCS showed strong antioxidant properties against 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), and reactive oxygen species radicals with inhibitory concentration 50 values were 765.48 ppm, 845.31 ppm, and 1760.00 ppm, respectively. The FCS also performed good antibacterial, antifungal, anticoagulant and anti-inflammatory activityies. Especially, it expressed a better inhibition activity on breast cancer cell line (MCF-7) than that on liver cancer cells (HepG2), lung cancer cells (NCI-H460), and cervical cancer cells (HeLa). FCS demonstrated potential utility in functional food, cosmeceutical, and pharmaceutical industries. In the trend of discovering new sources for fucoidan with outstanding bioactivities, this report would contribute a basic platform and valuable information for further studies on fucoidan from C. Submersum.

Endometrial thickness and uterine artery Doppler parameters as soft markers for prediction of endometrial cancer in postmenopausal bleeding women: a cross-sectional study at tertiary referral hospitals from Vietnam

Phuc Nhon Nguyen,Van Tuan Nguyen 대한산부인과학회 2022 Obstetrics & Gynecology Science Vol.65 No.5

ObjectiveTo determine the value of endometrial thickness (ET) and Doppler indices of uterine artery (UtA) as sonographic markersin predicting endometrial cancer (EC) among postmenopausal bleeding (PMB) women in low-resource settings asVietnam. MethodsThis cross-sectional study was conducted at the Hue University Hospital and Hue Central Hospital between June 2016and June 2019. The study enrolled all women who complained of PMB and were followed by transvaginal Dopplerultrasound. Their definitive histopathological examination was the gold standard for comparison. ResultsThe UtA Doppler indices, including resistance index (RI), pulsatility index (PI), and peak systolic velocity (PSV), weresignificantly lower in the malignant group than in the benign group. The threshold values of the UtA, RI ≤0.73 andPI ≤1.42, were found with an area under receiver operating characteristic curve (AUC) of 0.85-0.88, and the sensitivityand specificity were 91.3% and 83.3%, respectively. Unlike PSV, the diagnostic value was the lowest, with an AUC of0.72. ET was a good predictor for the diagnosis of EC, with an AUC of 0.89. In women with PMB, when using the cutoffvalue of EC more than 12.5 mm, the sensitivity and specificity were 93.8% and 77.8%, respectively. In addition, thehigher the stage of EC, the lower the RI and PI and the greater the EC. ConclusionET, and RI, PI, and PSV of the UtA could help in differentiating malignant from benign endometrial changes. Pulsedultrasonic Doppler velocimetry seems to play a role in predicting the higher stages of EC. Further studies are neededto confirm these findings.

The Relationship between Social Capital, Knowledge Sharing and Enterprise Performance: Evidence from Vietnam

Thanh Nhon HOANG,Cong Bac TRUONG 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.11

This study investigates the relationship between social capital and enterprise performance with knowledge sharing as the mediator. By employing the data of 677 respondents collected from delivering questionnaires to small and medium-size firms in Vietnam in 2020, this study suggests a two-step approach that combines exploration factor analysis (EFA), confirmatory factor analysis (CFA), and path analysis (SEM). The empirical findings significantly support our proposed model by demonstrating that knowledge sharing mediates the connection between all three elements of social capital and enterprise performance. At the same time, the results emphasize the importance of knowledge sharing as a major benefit of social capital and a substantial driving element of both operational and financial performance. The results show that all three social capital qualities (structural, relational, and cognitive) significantly impact both tacit and explicit knowledge sharing, while knowledge is one of the main routes connecting social capital to enterprise performance. Hence, our research model may be used in future studies to evaluate social capital, knowledge sharing, and firm performance as a new theoretical model. Our results offer a plausible explanation for how social capital improves knowledge sharing and enterprise performance.

Relay Selection Scheme for Hierarchical Wireless Sensor Networks

Tran Nhon,Dong-Seong Kim 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.3

The influence of foreign novels on the formation and development of the novels in "Quoc ngu" (Vietnamese Roman Alphabet) in Cochinchina from the Late 19th th to the early 20th century

( Vo Van Nhon ) 한국외국어대학교 동남아연구소 2011 東南亞硏究 Vol.21 No.1

A Cell - based Smoothed Finite Element Method for Free Vibration and Buckling Analysis of Shells

Chien Thai-Hoang,Nhon Nguyen-Thanh,Hung Nguyen-Xuan,Timon Rabczuk,Stephane Bordas 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.2

This paper further extends a cell-based smoothed finite element method for free vibration and buckling analysis of shells. A fournode quadrilateral Mindlin-Reissner shell element with a gradient smoothing operator is adopted. The membrane-bending and geometrical stiffness matrices are computed along the boundaries of the smoothing cells while the shear stiffness matrix is calculated by an independent interpolation in the natural coordinates as in the MITC4 (the Mixed Interpolation of Tensorial Components)element. Various numerical results are compared with existing exact and numerical solutions and they are in good agreement. The advantage of the present formulation is that it retains higher accurate than the MITC4 element even for heavily distorted meshes without increasing the computational cost.

Rate-estimation-based relay selection scheme for large-scale wireless networks

Bach Long, Nguyen,Nhon, Tran,Kim, Dong-Seong IET 2016 IET COMMUNICATIONS Vol.10 No.12

<P>This study proposes rate-estimation-based relay selection scheme (RERSS) for large-scale wireless networks (LSWNs) that effectively distributes traffic of packets from a source to a sink. In an LSWN, direct data transmission from a source and a sink has been becoming a challenge. This is because of longer communication distance and more interference caused by more adjacent nodes. Hence, in order to transmit data packets to the sink, the source exploits neighbour nodes as relay nodes around it to forward packets through single-hop or multi-hop until reaching the sink. Different from the conventional cooperative relaying scheme, RERSS introduces a rate-estimation parameter A to select the forwarder for relaying messages. After determining A value of each neighbour relay node using a link rate stored in the advertising packet, the relay node whose A value meets the requirement of RERSS can be qualified as a forwarder of the source or the other relay node. Simulation results indicate the potential to not only increase throughput but also decrease energy consumption and end-to-end delay.</P>

Study on the Characteristics of X-ray Spectra in Imaging Diagnosis Using Monte Carlo Simulations

Khanh Ai Tran,Loan Thi Hong Truong,Nhon Van Mai,Phuong Nguyen Dang,Dung Thi Thuy Vo 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.7

X-rays are widely used in diagnostic imaging such as radiography and computed tomography. An understanding of the X-ray spectrum is essential for estimating the dose absorbed by the patient and for improving image quality. In this research, X-ray emission spectra were investigated by using two different approaches: a Monte Carlo method using the MCNP5 code and a semi-empirical calculation with SpekCalc software. The results were compared with each other to validate the Monte Carlo simulation of the X-ray spectra, so that the simulation model can be applied to estimating the dose rate distribution in X-ray imaging. The obtained results show good agreement between the two approaches, but some divergence is still observed in the characteristic X-ray peaks. In addition, the influence of X-ray tube parameters such as the peak voltage, filter, anode angle and target material on of the beam quality was investigated.

이핵 CGC의 구조적인 특성과 에틸렌/1-헥센의 공중합 거동과의 관계

노석균(Seok Kyun Noh),웽티레녕(Nguyen Thi Le Nhon),웬티레탄(Nguyen Thi Le Thanh),까오환투이미(Cao Phan Thuy My) 한국고분자학회 2011 폴리머 Vol.35 No.6

Para-xylene의 기본 구조로 연결된 4개의 이핵 CGC를 활용하여 에틸렌과 1-헥센의 공중합특성을 조사하여 중합촉매의 구조적인 특징이 중합에 미치는 영향을 조사하였다. 4가지의 이핵 constrained geometry catalyst(CGC) 중에서 3가지는 모두 para-xylene 다리로 연결되어 있으나 벤젠고리 부분에 각각 다른 치환체가 결합된 것으로서 치 환체는 수소(Catalyst 1), isopropyl(Catalyst 2), n-hexyl(Cataylst 3)이고, n-octyl(Catalyst 4)인 화합물이었 다. 이핵 메탈로센 4가지와 Dow 촉매를 사용하여 에틸렌과 1-헥센을 공중합시켜 다른 치환체를 가진 다리리간드의 구 조적인 특성변화가 촉매의 중합특성과 이로부터 생성되는 공중합체의 특성에 미치는 영향을 조사하였다. 실험 결과 다 리리간드의 특성에 따라 분명한 경향성과 차이점이 발견되었다. 중합활성은 치환체의 크기가 가장 작은 수소에서 가장 높았으며, isopropyl에서 가장 낮았으며 그 차이는 최대 3배 이상이었다. 반면 분자량은 치환체가 isopropyl인 촉매에서 생성된 공중합체가 가장 컸고, n-hexyl과 1-octyl 치환체 화합물에서 가장 작은 분자량의 공중합체가 생성되었으며 그 차이는 6배에 달하였다. 이핵 CGC의 공중합 특성은 치환체가 긴 알킬기인 n-hexyl 및 1-octyl 화합물이 가장 우수하여 동일한 조건에서 1-헥센을 가장 많이 함유하여 40% 이상의 1-헥센을 포함하는 에틸렌 공중합체를 제조할 수 있었다. 이러한 연구 결과는 촉매구조 변화에 의한 고분자 미세구조 조절이라는 고분자 합성의 가장 어려운 부분 이 xylene 다리를 가진 이핵 CGC의 치환체를 조절함으로써 가능함을 보여주는 결과이다. Effects of structural features of 4 dinuclear constrained geometry catalysts having paraxylene derivative bridge (DCGC) on copolymerization of ethylene and 1-hexene were investigated. The bridges of three catalysts have para-xylene backbone with a different substituent at benzene ring. The substituents were hydrogen (Catalyst 1), isopropyl (Catalyst 2), n-hexyl (Catalyst 3) and 1-octyl (Catalyst 4). It was found that Catalyst 1 having hydrogen as a substituent exhibited the greatest activity among the four dinuclear CGCs. On the other hand, Catalyst 2 containing isopropyl as a substituent showed the smallest activity. Very interestingly, Catalyst 2 was able to produce about 6 times higher molecular weight polymer than Catalyst 3 and 4. Catalyst 3 and 4 having a long alkyl chain substituent revealed the biggest comonomer response to generate polyethylene copolymer containing more than 40% 1-hexene contents. These results suggest that the control of the substituent of para-xylene bridge of dinuclear CGC can provide a proper method to adjust the microstructure of polyethylene copolymers.

대규모 무선 센서망을 위한 트래픽 기반 라우팅 알고리즘

두 두이 탄(Do Duy Tan),트란 녕(Tran Nhon),김동성(Dong-Sung Kim) 한국정보기술학회 2012 Proceedings of KIIT Conference Vol.2012 No.11

본 논문에서는 대규모 멀티 싱크 무선 센서망에서 효율적인 패킷 송수신을 위한 트래픽 기반의 라우팅 알고리즘을 제안한다. 각각의 노드는 자신의 트래픽 변화량을 이용하여 수신 노드까지의 경로를 결정한다. 제안된 방법을 위해 무선 센서망 노드의 트래픽 변화량은 다음과 같은 정보들을 고려한다. 첫 번째는 송신 노드부터 각각의 수신 노드까지의 거리 비용이고 두 번째는 주변 노드 주위에 대기하고 있는 노드들로부터의 트래픽 정보이다. 모의실험 결과를 통한 분석을 살펴보면 제안된 방법은 대규모 무선 센서망의 패킷 지연시간을 효율적으로 감소시키고 트래픽 과부하 상황에서 처리율의 향상을 보였다. This paper proposes a traffic-aware routing protocol for large-scale wireless sensor networks that make traffic of packets from sources to sinks is more efficient. Each node decides the route to reach a sink by its own gradient field. The parameters of a node"s gradient include (1) the distance cost from source to a respective sink, and (2) traffic information from nodes staying around it (neighboring nodes). The simulation results show the performance of the proposed scheme indicate that it effectively reduces the overall packet delay and improves throughput ratio under heavy traffic.