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Search Results: 1 - 10 of 132655 matches for " Thuy T. Le "
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Research and innovative design of a zeroemissions vehicle by multidisciplinary student teams in multi-years
Raymond K. Yee,Tai-Ran Hsu,Thuy T. Le
Computer Science , 2013,
Abstract: This paper presents a unique learning and research experience for students from mechanical and electrical engineering majors in a course on senior design projects involving research and development, design and production of a proof-of-concept electric vehicle, the ZEM (Zero EMissions) vehicle. The ZEM vehicle combined positive aspects and latest technologies in electric vehicle design,solar-electric power conversions, and ergonomic human power into one affordable and environmentally sustainable vehicle for urban transportation. The 43 mechanical and 10 electrical engineering majors plus 7 students from business participated in this multidisciplinary project spanned over two academic years. The students involved in this multiyear endeavor gained valuable experiences in real-world working environment with multifunctional and multi-year sub-groups. The success of this new attempt in conducting senior design projects classes have set a model for faculty members in the authors' university in conducting similar courses.
Application of Null Space Based Behavior Control to the Swarm Robot’s Control  [PDF]
Le Thi Thuy Nga, Le Hung Lan
Modern Mechanical Engineering (MME) , 2015, DOI: 10.4236/mme.2015.53009
Abstract: This paper proposes a solution to controls warm robots in an effort to avoid obstacles, moving to the goal by the method of Null Space based Behavior (NSB) control of an individual in the swarm. This paper also provides the stability analysis of the converging process by investigating the relationship between single agents, and the analysis result is proved by using the Lyapunov theory. Finally, the simulation results in two-dimensional space have confirmed the obtained theoretical results.
Evaluation of Landslide Susceptibility in Cau River Basin Using a Physical-Based Model under Impact of Climate Change  [PDF]
Thi Thanh Thuy Le, Seiki Kawagoe
Open Journal of Modern Hydrology (OJMH) , 2019, DOI: 10.4236/ojmh.2019.91001
Abstract: This paper evaluated the probability of landslide susceptibilities through the applica-tion of the Transient Rainfall Infiltration and Grid-Based Region Slope-Stability model in Cau river basin (Vietnam) using the scenarios-based approach under the influence of the warming climate. The tested cases were developed based on various options including rainfall amount and distribution, soil depth determination, and land-cover conditions. Input data for extreme rain events included historical rainstorm in 2013, the Probable Maximum Precipitation (PMP) with the durations of 24 hours and 48 hours. The results illustrated the reduction of slope stability when the land cover changed from land-use data in 2007 (Ha12) to land-use data in 2015 (Ha22). When the whole region was assumed to be replaced by soil (Ha02), the factor of safety (Fs) decreased to lower magnitude when compared to Fs value regarding to changes in land cover condition (Ha12 & Ha22) and changes in soil-depth (Ha33). The model simulations demonstrated the agreement with the slope-failure hazard association with the destabilizing factor such as slope-cutting activities at historical landslide events. Under the same land-cover and soil depth condition, the average value of factor of safety regarding to the historical rainstorm in 2013 (Ha32) declined by 0.069 and 0.189 when compared to Fs of the 24-hour PMP with the storm distribution type 3 (1332) and Fs of the 48-hour PMP with the storm distribution type 3 (2332), respectively. The results reveal that in a warming climate, changes in extreme precipitation in terms of rain-total, rain-duration, and rain-distribution would result in the expansion of slope instability in the hilly region. This application is considered as a prevailing method for landslide susceptibility analysis and would provide important information for authorities in developing adequate land-management in the river basin.
Biomonitoring of organic and inorganic chemicals in the hair of Vietnamese people via spectral and chromatographic analysis  [PDF]
Le Phuoc Cuong, Le Thi Xuan Thuy, Micheal Evgenev
Journal of Biophysical Chemistry (JBPC) , 2013, DOI: 10.4236/jbpc.2013.41001
Abstract:

A combination of spectral and chromatographic analytical methods has been executed to monitor chemicals in the hair of Vietnamese people. Methods were developed for the determination of some chemical elements in hair by inductively coupled-plasma atomic emission spectroscopy with limits of detection reaching 1 - 100 μg·l1. A supercritical fluid extraction (SFE) and clean-up procedures were established for isolating organochlorine pollutants (OCPs) and organophosphorus pesticides (OPPs) from the hair of the Vietnamese test subjects. Eight OCPs and OPPs were determined by SFE with carbon dioxide only and methanol-modified carbon dioxide extraction at 350 bar and 45, followed by gas chromatography coupled to mass spectrometry. The results indicated that OCPs can be extracted quantitatively using CO2 only, whereas OPPs require a modifier for extraction. The limits of detection that were found were between 0.7 to 1.3 μg·g1, and good linearity (r2 > 0.9861) was achieved within the tested ranges. The activities of the N-acetyltransferase (NAT) and the monooxygenases cytochrome P450 (CYP 450) were determined and compared to the acetylation and oxidation phenotypes of healthy Vietnamese test subjects. The variations in the concentration of chemical elements in human hair were shown to be dependent upon the activities of the two-phase metabolic system, on the individual’s gender and the duration of residence within Russia.

Jaundice in Adult in-Patients at a Tertiary General Hospital  [PDF]
Le Ngoc Hung, Nguyen Thi Le Huong, Nguyen Thi Thuy An
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.32001
Abstract: Objective: The aim of the study is to investigate the “new-onset jaundice” incidence, map of causes, approaching method, and risk factors for treatment failure in adult in-patients at a tertiary general hospital as Cho Ray Hospital, Ho Chi Minh City, Viet Nam. Method: Retrospective study was done on 416 jaundice patients administered over 38 continuous days. Laboratory tests investigated were total bilirubin, direct bilirubin, AST, ALT, AST/ALT ratio, GGT, AP, bilirubin and urobilinogen in urine. Jaundice was defined as total bilirubin ≥ 2.5 mg/dL, direct bilirubin jaundice defined as direct bilirubin > 2 mg/dL and D/T percentage > 60%, the severity of AST, ALT evaluated according to Common Terminology Criteria for Adverse Events, AST/ALT ratio, and bilirubin, urobilinogen in urine. Outcome of treatment were classified in two groups: failure (dead or discharge due to worse status) and success. Descriptive statistics and analytic statistics were applied, mono-variable analysis and multinomial logistic regression to find out the independent risk factors for treatment failure. Results: The incidence of “new-onset” jaundice in adult patients was 11 ± 5 person/day. The map of jaundice included 3 phases as pre-heaptic 13.7%, in-hepatic 58.2%, and post-hepatic 22.8%. Pancreatic and biliary tract diseases accounted 17.1%, then cirrhosis 16.3%, liver tumor 14.7%, hepatitis 8.9%, sepsis 8.9%, hematology diseases 7.9%, and cardiac diseases 7.5%. A guide for approaching causes of jaundice basing on 7 parameters as total bilirubin, D/T percentage, severity of ALT, AST/ALT ratio, severity of GGT, and bilirubin and urobilinogen in urine was established. The overall mortality was 7.5% (31/416), sepsis had highest death rate of 37.8% (14/37). Sepsis and AST/ALT ratio > 2 were the two independent risk factors of mortality. Conclusion: At tertiary hospital, jaundice is common sign in adult patient, diverse enormously in many clinical wards. The map of causes of jaundice completed all 3 phases: pre-hepatic, intra-hepatic and post-hepatic phase. Drug hepatitis jaundice was an important cause in hepatitis. Sepsis had highest mortality in adult jaundice patients. Combination of 7 criteria as total bilirubin, the D/T percentage, ALT severity, AST/ALT ratio, GGT, bilirubin and urobilinogen in urine gave the guide for approaching to jaundice. Sepsis and AST/ALT ratio > 2 were independent risk factors of treatment failure. The survey of jaundice in adult in-patients in a tertiary general government hospital gave the full picture for this common pathological sign.
Effective Chikungunya Virus-like Particle Vaccine Produced in Insect Cells
Stefan W. Metz,Joy Gardner,Corinne Geertsema,Thuy T. Le,Lucas Goh,Just M. Vlak,Andreas Suhrbier,Gorben P. Pijlman
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002124
Abstract: The emerging arthritogenic, mosquito-borne chikungunya virus (CHIKV) causes severe disease in humans and represents a serious public health threat in countries where Aedes spp mosquitoes are present. This study describes for the first time the successful production of CHIKV virus-like particles (VLPs) in insect cells using recombinant baculoviruses. This well-established expression system is rapidly scalable to volumes required for epidemic responses and proved well suited for processing of CHIKV glycoproteins and production of enveloped VLPs. Herein we show that a single immunization with 1 μg of non-adjuvanted CHIKV VLPs induced high titer neutralizing antibody responses and provided complete protection against viraemia and joint inflammation upon challenge with the Réunion Island CHIKV strain in an adult wild-type mouse model of CHIKV disease. CHIKV VLPs produced in insect cells using recombinant baculoviruses thus represents as a new, safe, non-replicating and effective vaccine candidate against CHIKV infections.
Influence of the Presence of Chemical Additives on the Thermal Properties of Starch  [PDF]
Mostaq Ahammad, T. Thuy Minh Nguyen
Food and Nutrition Sciences (FNS) , 2016, DOI: 10.4236/fns.2016.79079
Abstract: Starch is an essential but very complex semi-crystalline biopolymer. In addition to being an important food source, numerous industrial applications have been proposed for this renewable material. Most applications are highly dependent on the physical properties of the material which are a strong function of the amount of intra- and inter-molecular interactions. This research investigates the potential to manipulate the type and amount of chain-chain interactions to tailor the properties of starch for different applications. Three types of additives acting as probe molecules were used to vary these interactions by changing the amounts and the pH of each sample: a very polar organic molecule, glycerol, a high electron density compound, TiO2, and a mostly hydrophobic organic molecule, cholesterol. Differential scanning calorimetry was used to determine the strength and the amount of chain-chain interactions while Fourier transform infrared spectroscopy was used to follow the nature of these interactions. Results show that the different probe molecules do interact with starch but form chemical interactions at different locations on the chain. We conclude that with proper play on amount, type of additive, temperature cycle, and pH a composite of starch could be tailored for numerous and specific applications.
Differentiation of breast cancer stem cells by knockdown of CD44: promising differentiation therapy
Phuc V Pham, Nhan LC Phan, Nhung T Nguyen, Nhung H Truong, Thuy T Duong, Dong V Le, Kiet D Truong, Ngoc K Phan
Journal of Translational Medicine , 2011, DOI: 10.1186/1479-5876-9-209
Abstract: We isolated a breast cancer cell population (CD44+CD24- cells) from primary cultures of malignant breast tumors. These cells were sorted into four sub-populations based on their expression of CD44 and CD24 surface markers. CD44 knockdown in the BCSC population was achieved using small hairpin RNA lentivirus particles. The differentiated status of CD44 knock-down BCSCs was evaluated on the basis of changes in CD44+CD24- phenotype, tumorigenesis in NOD/SCID mice, and gene expression in relation to renewal status, metastasis, and cell cycle in comparison with BCSCs and non-BCSCs.Knockdown of CD44 caused BCSCs to differentiate into non-BCSCs with lower tumorigenic potential, and altered the cell cycle and expression profiles of some stem cell-related genes, making them more similar to those seen in non-BCSCs.Knockdown of CD44 is an effective strategy for attacking the stemness of BCSCs, resulting in a loss of stemness and an increase in susceptibility to chemotherapy or radiation. The results of this study highlight a potential new strategy for breast cancer treatment through the targeting of BCSCs.The existence of breast cancer stem cells (BCSCs) in malignant breast tumors has been demonstrated in many previous studies [1-4]. These stem cells exhibit a range of phenotypes, including CD44+CD24-, CD44+CD24-/dim, CD44+CD24-/dimESA+ and CD44+CD24-Lin- [1-4]. These cells possess specific characteristics, such as anti-tumor-drug and radiation resistance [5]. Because they can escape the effects of chemotherapy or radiation therapy, relapse remains a possibility. The resistance of these cells may be mediated by signaling through the Wnt pathway [6]. They also express high levels of anti-apoptotic proteins, such as survivin and Bcl [7], and evidence suggests that alterations in DNA repair and cell cycle kinetics may be involved in their resistance to radiation and chemotherapy [8]. In addition, BCSCs have been shown to be resistant to hormone therapy [9-11]. The discovery of th
Mutation Rates of TGFBR2 and ACVR2 Coding Microsatellites in Human Cells with Defective DNA Mismatch Repair
Heekyung Chung, Dennis J. Young, Claudia G. Lopez, Thuy-Anh T. Le, Jeffrey K. Lee, Deena Ream-Robinson, Sherry C. Huang, John M. Carethers
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003463
Abstract: Microsatellite instability promotes colonic tumorigenesis through generating frameshift mutations at coding microsatellites of tumor suppressor genes, such as TGFBR2 and ACVR2. As a consequence, signaling through these TGFβ family receptors is abrogated in DNA Mismatch repair (MMR)-deficient tumors. How these mutations occur in real time and mutational rates of these human coding sequences have not previously been studied. We utilized cell lines with different MMR deficiencies (hMLH1?/?, hMSH6?/?, hMSH3?/?, and MMR-proficient) to determine mutation rates. Plasmids were constructed in which exon 3 of TGFBR2 and exon 10 of ACVR2 were cloned +1 bp out of frame, immediately after the translation initiation codon of an enhanced GFP (EGFP) gene, allowing a ?1 bp frameshift mutation to drive EGFP expression. Mutation-resistant plasmids were constructed by interrupting the coding microsatellite sequences, preventing frameshift mutation. Stable cell lines were established containing portions of TGFBR2 and ACVR2, and nonfluorescent cells were sorted, cultured for 7–35 days, and harvested for flow cytometric mutation detection and DNA sequencing at specific time points. DNA sequencing revealed a ?1 bp frameshift mutation (A9 in TGFBR2 and A7 in ACVR2) in the fluorescent cells. Two distinct fluorescent populations, M1 (dim, representing heteroduplexes) and M2 (bright, representing full mutants) were identified, with the M2 fraction accumulating over time. hMLH1 deficiency revealed 11 (5.91×10?4) and 15 (2.18×10?4) times higher mutation rates for the TGFBR2 and ACVR2 microsatellites compared to hMSH6 deficiency, respectively. The mutation rate of the TGFBR2 microsatellite was ~3 times higher in both hMLH1 and hMSH6 deficiencies than the ACVR2 microsatellite. The ?1 bp frameshift mutation rates of TGFBR2 and ACVR2 microsatellite sequences are dependent upon the human MMR background.
Stat3 and CCAAT/enhancer binding protein beta (C/EBP-beta) regulate Jab1/CSN5 expression in mammary carcinoma cells
Terry J Shackleford, Qingxiu Zhang, Ling Tian, Thuy T Vu, Anita L Korapati, Angela M Baumgartner, Xiao-Feng Le, Warren S Liao, Francois X Claret
Breast Cancer Research , 2011, DOI: 10.1186/bcr2902
Abstract: To identify potential regulators of Jab1 transcription, we cloned the 5' upstream region of the human Jab1 gene and mapped its transcriptional start site. We identified binding sequences for the CCAAT/enhancer binding protein (C/EBP) and GATA, as well as a signal transducer and activator of transcription-3 (Stat3) consensus sequence overlapping the C/EBP site, using 5'- deletion analysis and a gene reporter assay. Mutational analysis of these binding sites was performed to confirm their roles in promoting Jab1 transcription in breast cancer cells. We further confirmed these binding sites using electrophoretic mobility shift assays (EMSAs) and chromatin immunoprecipitation (ChIP) assays. We also analyzed whether the siRNA-mediated inactivation of Stat3 and Src could reduce Jab1-promoter activity and whether interleukine-6 (IL-6) could mediate increased Jab1 expression through Stat3 signaling.We identified binding sequences for C/EBP, GATA, as well as a Stat3 consensus sequence overlapping the C/EBP site in the promoter region of Jab1. C/EBP-beta2 is a potential transcriptional activator of Jab1 and mutation of the C/EBP/Stat3 binding site significantly reduced Jab1-promoter activity. In addition, inhibiting Stat3 significantly reduced Jab1-promoter activation. EMSA and ChIP assays confirmed that C/EBP, GATA1 and Stat3 bind to Jab1 promoter in breast carcinoma cells. We also found that Src, an activator of Stat3, is involved in Jab1-promoter activation. siRNA knockdown of Src reduced the Jab1-promoter activity, similar to the results seen when Stat3 was inhibited in breast carcinoma cells. Interestingly, reactivation of Stat3 in normal mammary epithelial cells (MCF-10A, MCF-10F) is sufficient to reactivate Jab1 expression. Treatment with the cytokine IL-6 resulted in increased Jab1 expression that was blocked by inhibition of Stat3.These findings reveal a novel mechanism of Jab1 gene regulation and provide functional and mechanistic links between the Src/Stat3 and IL-
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