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Search Results: 1 - 10 of 10949 matches for " Tran Tan Thanh "
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Synthesis, Antioxidant and Antimicrobial Activities of a Novel Series of Chalcones, Pyrazolic Chalcones, and Allylic Chalcones  [PDF]
Tan Nhut Doan, Dao Thanh Tran
Pharmacology & Pharmacy (PP) , 2011, DOI: 10.4236/pp.2011.24036
Abstract: A new series of chalcones (4a-c) and allylicchalcones (11a-b) have been prepared by the Claisen-Schmidt condensation. A novel series of pyrazolicchalcones (5a-c) have been synthesized by the reaction of respective chalcones (4a-c) and hydrazine hydrate. The structures of the compounds were confirmed by spectral data (infrared spectroscopy and 1H nuclear magnetic resonance). All of the compounds (4/5a-c and 11a-b) have been tested for their antimicrobial activities (agar disc-diffusion method) and antioxidant activities (1,1-biphenyl-2-picrylhydrazyl free radical scavenging method). The test compounds failed to show antibacterial properties (4a-c, 5b, and 11a-b) or exhibited such properties poorly (5a and 5c). None of the test compounds displayed antifungal properties. Of the compounds tested, compounds 5a-c and 11a-b exhibited promising antioxidant activities.
Assessment of Microalbuminuria for Early Diagnosis and Risk Prediction in Dengue Infections
Nguyen Thi Hanh Tien, Phung Khanh Lam, Huynh Thi Le Duyen, Tran Van Ngoc, Phan Thi Thanh Ha, Nguyen Tan Thanh Kieu, Cameron Simmons, Marcel Wolbers, Bridget Wills
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054538
Abstract: Background Dengue is the most important arboviral infection of humans. Following an initial febrile period, a small proportion of infected patients develop a vasculopathy, with children at particular risk for severe vascular leakage and shock. Differentiation between dengue and other common childhood illnesses is difficult during the early febrile phase, and risk prediction for development of shock is poor. The presence of microalbuminuria is recognized as a useful early predictor for subsequent complications in a number of other disorders with vascular involvement. Significant proteinuria occurs in association with dengue shock syndrome and it is possible that early-phase microalbuminuria may be helpful both for diagnosis of dengue and for identification of patients likely to develop severe disease. Methodology/Principal Findings We measured formal urine albumin to creatinine ratios (UACRs) in daily samples obtained from a large cohort of children with suspected dengue recruited at two outpatient clinics in Ho Chi Minh City, Vietnam. Although UACRs were increased in the 465 confirmed dengue patients, with a significant time trend showing peak values around the critical period for dengue-associated plasma leakage, urine albumin excretion was also increased in the comparison group of 391 patients with other febrile illnesses (OFI). The dengue patients generally had higher UACRs than the OFI patients, but microalbuminuria, using the conventional cutoff of 30 mg albumin/g creatinine discriminated poorly between the two diagnostic groups in the early febrile phase. Secondly UACRs did not prove useful in predicting either development of warning signs for severe dengue or need for hospitalization. Conclusion/Significance Low-level albuminuria is common, even in relatively mild dengue infections, but is also present in many OFIs. Simple point-of-care UACR tests are unlikely to be useful for early diagnosis or risk prediction in dengue endemic areas.
Over-expression of the mitogen-activated protein kinase (MAPK) kinase (MEK)-MAPK in hepatocellular carcinoma: Its role in tumor progression and apoptosis
Hung Huynh, Thi Thanh Tuyen Nguyen, Kah-Hoe Pierce Chow, Puay Hoon Tan, Khee Chee Soo, Evelyne Tran
BMC Gastroenterology , 2003, DOI: 10.1186/1471-230x-3-19
Abstract: Immuno-histochemistry was used to localize phosphorylated MAPK and MEK1/2 in the tissues. 3-(4,5-Dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) assay and ELISA were used to determine cell viability and cell proliferation. Deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay was used to detect apoptotic cells. Western blots analysis was performed to determine the levels of proteins involved in the MEK-MAPK and apoptotic pathways. Transfection study was performed to assess the role of MEK-MAPK pathway in growth and survival of liver cancer cells.We report that phosphorylation of MEK1/2 at Ser217/221 was detected by immuno-histochemistry in 100% (46 of 46) of HCCs examined. A positive signal was localized in the nuclei of hepatocarcinoma cells but not in dysplastic hepatocytes or stromal cells. Over-expression and phosphorylation of MAPK was also detected in 91% (42 of 46) and 69% (32 of 46) of HCCs examined, respectively. The percentage of cells showing positively for phosphorylated MEK1/2 increased with advancing tumor stage. In vitro, treatment of human HepG2 and Hep3B cells with MEK1/2 specific inhibitors U0126 and PD98059 led to growth inhibition and apoptosis. U0126 induced the release of cytochrome c and increased the cleavage of caspase-3, caspase-7, and poly ADP-ribose polymerase (PARP). Inhibition of phosphatidylinositol 3-kinase (PI-3K), c-Jun N-terminal kinase (JNK) and p38 kinase activities caused only a mild apoptosis in HepG2 and Hep3B cells. Activated MEK1-transfected cells were more resistant to UO126-induced apoptosis in vitro and formed larger tumors in SCID mice than mock-transfected cells.In conclusion, our results demonstrate that MEK-MAPK plays an important role in the growth and survival of liver cancer cells and suggest that blocking MEK-MAPK activity may represent an alternative approach for the treatment of liver cancer.HCC is one of the most common malignancies in South East Asia. The incidence of HCC is be
A mixed method for Dirichlet problems with radial basis functions
Norbert Heuer,Thanh Tran
Mathematics , 2013,
Abstract: We present a simple discretization by radial basis functions for the Poisson equation with Dirichlet boundary condition. A Lagrangian multiplier using piecewise polynomials is used to accommodate the boundary condition. This simplifies previous attempts to use radial basis functions in the interior domain to approximate the solution and on the boundary to approximate the multiplier, which technically requires that the mesh norm in the interior domain is significantly smaller than that on the boundary. Numerical experiments confirm theoretical results.
A generalization of reduced Arakelov divisors of a number field
Nguyen Thanh Ha Tran
Mathematics , 2015,
Abstract: Let $C \geq 1$. Inspired by LLL-algorithm, we define strongly $C$-reduced divisors of a number field $F$ which are generalized from the concept of reduced Arakelov divisors. Moreover, we show that strongly $C$-reduced Arakelov divisors still keep "nice" properties of the reduced ones: They form a finite, regularly distributed set in the Arakelov class group and the oriented Arakelov class group of $F$.
Radial basis functions for the solution of hypersingular operators on open surfaces
Norbert Heuer,Thanh Tran
Mathematics , 2012,
Abstract: We analyze the approximation by radial basis functions of a hypersingular integral equation on an open surface. In order to accommodate the homogeneous essential boundary condition along the surface boundary, scaled radial basis functions on an extended surface and Lagrangian multipliers on the extension are used. We prove that our method converges quasi-optimally. Approximation results for scaled radial basis functions indicate that, for highly regular radial basis functions, the achieved convergence rates are close to the one of low-order conforming boundary element schemes. Numerical experiments confirm our conclusions.
On reduced Arakelov divisors of real quadratic fields
Nguyen Thanh Ha Tran
Mathematics , 2014,
Abstract: We generalize the concept of reduced Arakelov divisors and define $C$-reduced divisors for a given number $C \geq 1$. These $C$-reduced divisors have very nice properties which are similar to the properties of reduced ones. In this paper, we describe an algorithm to test whether an Arakelov divisor of a real quadratic field $F$ is $C$-reduced in polynomial time in $\log|\Delta_F|$ with $\Delta_F$ the discriminant of $F$. Moreover, we give an example of a cubic field for which our algorithm does not work.
Computing spaces of effective Arakelov divisors of a number field
Tran Nguyen Thanh Ha
Mathematics , 2015,
Abstract: The function $h^0$ of a number field is analogous to the dimension of the Riemann-Roch spaces at divisors on an algebraic curve. We provide a method to compute this function for number fields with unit group of rank at most 2, especially in case of large discriminant. This method is based on using LLL-reduced bases and "Jump algorithm" as well as Poisson summation formula.
The size function of quadratic extensions of complex quadratic fields
Nguyen Thanh Ha Tran
Mathematics , 2015,
Abstract: The function $h^0$ of a number field is an analogue of the dimension of the Riemann-Roch spaces of divisors on an algebraic curve. In this paper, we prove the conjecture of Schoof and Van der Geer about the maximality of $h^0$ at the trivial Arakelov divisor for quadratic extensions of complex quadratic fields.
Prediction of the Local Scour at the Bridge Square Pier Using a 3D Numerical Model  [PDF]
Nguyen Viet Thanh, Dang Huu Chung, Tran Dinh Nghien
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.42005
Abstract: In this paper, the problem on local scour around a single square pier was studied by using both the numerical and physical models. The numerical model for the study is FSUM based on a finite-difference method to solve the Reynolds averaged Navier-Stokes equations (RANS) and the equations for suspended sediment concentration and bed morphology. The computed result was verified through data measured in the experimental flume with a sand bed. In general, the typical features of local scour around the pier were successfully simulated by FSUM, such as stream flow, bow flow, down flow, horseshoe vortex. The comparison between the computation and experiment data shows a quite good fitness. Both numerical model and experiment results show that the maximum scour depth occurs at two front edges of the pier. Although the computed result shows a little bigger scour depth in comparison with the measurement in the physical model, it still confirms the reliability of numerical model in some measure.
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