73 results on '"T. L. Nguyen"'
Search Results
2. <scp>l</scp> ‐lactic acidosis confers insensitivity to PKC inhibitors by competing for uptake via monocarboxylate transporters
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Chia-Hung Chen, You-Chi Liu, Jhih-Yi Chiou, Wei Chien Huang, Chih Yen Tu, Chao-Jung Chen, Khuong T L Nguyen, Yi-Cheng Shen, Fang-Ju Cheng, and Chih-Hsin Tang
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Monocarboxylic Acid Transporters ,Lung Neoplasms ,Physiology ,Clinical Biochemistry ,GPR81 ,Pharmacology ,Carcinoma, Non-Small-Cell Lung ,Tumor Microenvironment ,medicine ,Humans ,Lactic Acid ,Epidermal growth factor receptor ,Receptor ,Protein Kinase Inhibitors ,Protein kinase C ,Monocarboxylate transporter ,Tumor microenvironment ,Symporters ,biology ,Chemistry ,Cell Biology ,medicine.disease ,ErbB Receptors ,Lactic acidosis ,biology.protein ,Acidosis, Lactic ,Tyrosine kinase - Abstract
Targeting protein kinase C (PKC) family was found to repress the migration and resistance of non-small cell lung cancer cells to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). However, none of the PKC inhibitors has been approved for anticancer therapy yet due to the limited efficacy in clinical trials, and the underlying mechanisms remain unclear. l-lactic acidosis, a common condition comprising high l-lactate concentration and acidic pH in the tumor microenvironment, has been known to induce tumor metastasis and drug resistance. In this study, l-lactic acid was found to reverse the inhibitory effects of pan-PKC inhibitors GO6983 on PKC activity, cell migration, and EGFR-TKI resistance, but these effects were not affected by the modulators of lactate receptor GPR81. Interestingly, blockade of lactate transporters, monocarboxylate transporter-1 and -4 (MCT1 and MCT4), attenuated the intracellular level of GO6983, and its inhibitory effect on PKC activity, suggesting that lactic acid promotes the resistance to PKC inhibitors by competing for the uptake through these transporters rather than by activating its receptor, GPR81. Our findings explain the underlying mechanisms of the limited response of PKC inhibitors in clinical trials.
- Published
- 2021
3. A dissipative quantum simulator of lasing dynamics at the few quanta level
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T. Behrle, T. L. Nguyen, F. Reiter, D. Baur, B. de Neeve, M. Stadler, S. Yelin, and J. P. Home
- Published
- 2022
4. Geological structure of central Vietnam by interpretation processing of gravitational survey data using the 'COSCAD 3D' computer technology
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T. H. Phan, A. V. Petrov, M. Ph. Do, M. G. Lai, and T. L. Nguyen
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QE1-996.5 ,“coscad 3d” computer technology ,correlation ,tectonic dislocations ,methods of probabilistic-statistical approach ,tracing of anomaly axes ,Geology ,General Medicine ,central vietnam ,gravitational field - Abstract
Background. The central regions of Vietnam are of strategic importance for the Republic, being, in fact, the gateway to the ASEAN countries. Investing in the exploration and evaluation of mineral resources, in particular ore minerals hidden at great depths, is a specific and necessary task for the country.Aim. To clarify the structural-tectonic scheme of the analysed area and to identify the main fault systems and zoning of the Central Vietnam area by the gravitational field based on classification algorithms.Materials and methods. The objectives were achieved by assessing the total gradient of the gravitational field, analysing the distribution of the field variance and the results of tracing the axes of the gravitational field anomaly. Interpretation processing of gravity data was carried out using the “COSCAD 3D” computer technology of statistical and spectral correlation data analysis.Results. The defined fault systems, which play an important role in the processes of mineral formation, have a northwestern, northeastern and latitudinal strike. The zoning of the study area according to the gravitational field, its characteristics and available geological information made it possible to identify 13 homogeneous areas. Each area is characterised by a certain level of gravitational field, the values of dispersion and total field gradient, as well as correlations between attributes. The classification results confirms the complexity of the geological structure of the area under study and the presence of three main strikes of the systems of tectonic dislocations – northwestern, northeastern and latitudinal.Conclusions. A large number of tectonic dislocations of various strikes and intensities, revealed using the methods of the probabilistic-statistical approach, implemented in the “COSCAD 3D” computer technology, indicates that the area under study is promising in terms of ore deposits.
- Published
- 2021
5. Single-cell analysis of human basal cell carcinoma reveals novel regulators of tumor growth and the tumor microenvironment
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Christian F. Guerrero-Juarez, Gun Ho Lee, Yingzi Liu, Shuxiong Wang, Matthew Karikomi, Yutong Sha, Rachel Y. Chow, Tuyen T. L. Nguyen, Venus Sosa Iglesias, Sumaira Aasi, Michael L. Drummond, Qing Nie, Kavita Sarin, and Scott X. Atwood
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Multidisciplinary ,Skin Neoplasms ,Carcinoma ,Basal Cell ,Mice ,Carcinoma, Basal Cell ,Genetics ,Tumor Microenvironment ,2.1 Biological and endogenous factors ,Animals ,Humans ,Hedgehog Proteins ,Aetiology ,Single-Cell Analysis ,Ecosystem ,Cancer - Abstract
How basal cell carcinoma (BCC) interacts with its tumor microenvironment to promote growth is unclear. We use singe-cell RNA sequencing to define the human BCC ecosystem and discriminate between normal and malignant epithelial cells. We identify spatial biomarkers of tumors and their surrounding stroma that reinforce the heterogeneity of each tissue type. Combining pseudotime, RNA velocity–PAGA, cellular entropy, and regulon analysis in stromal cells reveals a cancer-specific rewiring of fibroblasts, where STAT1, TGF-β, and inflammatory signals induce a noncanonical WNT5A program that maintains the stromal inflammatory state. Cell-cell communication modeling suggests that tumors respond to the sudden burst of fibroblast-specific inflammatory signaling pathways by producing heat shock proteins, whose expression we validated in situ. Last, dose-dependent treatment with an HSP70 inhibitor suppresses in vitro vismodegib-resistant BCC cell growth, Hedgehog signaling, and in vivo tumor growth in a BCC mouse model, validating HSP70’s essential role in tumor growth and reinforcing the critical nature of tumor microenvironment cross-talk in BCC progression.
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- 2022
6. Population-Based Pharmacokinetics and Dose Optimization of Imipenem in Vietnamese Critically-Ill Patients
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Thanh D Dinh, Hung N Nguyen, Ba Hai Le, Thuy T T Nguyen, and Huong T L Nguyen
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Pharmacology ,Infectious Diseases ,Infection and Drug Resistance ,Pharmacology (medical) - Abstract
Thanh D Dinh,1,2 Hung N Nguyen,1 Ba Hai Le,1 Thuy TT Nguyen,1 Huong TL Nguyen1 1Department of Clinical Pharmacy, Hanoi University of Pharmacy, Hanoi, Vietnam; 2Phu Tho General Hospital, Viá»t Trì, Phu Tho Province, VietnamCorrespondence: Huong TL Nguyen, Department of Clinical Pharmacy, Hanoi University of Pharmacy, 13, 15 â Lê Thánh Tông, Hoà n Kiếm, Hà Ná»i, 100000, Vietnam, Tel +84904308406, Email huongntl@hup.edu.vnPurpose: The purpose of this study was to characterize the population-based pharmacokinetic (POP-PK) profile of imipenem in Vietnamese adult patients and to assess the probability of target attainment (PTA) of the pharmacokinetic/pharmacodynamic (PK/PD) parameter to determine the optimal dose.Patients and Methods: A POP-PK model of imipenem was developed in patients with severe infection from a 1500-bed general hospital in Vietnam, using MONOLIX 2019. After the initial dose infusion, 6 blood samples per patient were collected to measure plasma imipenem levels. Eight covariates (eg, age, weight) were investigated to ascertain their influence on imipenemâs PK. Monte Carlo simulations were performed to determine the PTA for the time in which the total steady-state imipenem concentrations remained above the MIC (T>MIC) for 40% and 100% of the dosing interval.Results: The best fit to the PK data was a two-compartment model with inter-individual variability (IIV) in clearance (CL), central volume of distribution (Vc), intercompartmental clearance (Q), and peripheral volume of distribution (Vp). Only creatinine clearance was retained as a covariate on CL in the final model. The typical value of CL and Vc were estimated to be 4.79 L/h and 11.1 L, respectively. The between-subject variability in this population was noted to be high (> 38%, especially for IIV on Q at 110%). Prolonged or continuous infusion demonstrated efficacy (40% T>MIC) against bacteria with a MIC of 4mg/L. To achieve 100% T>MIC or bacteria with MIC> 4 mg/L, however, the number of doses must be increased while maintaining the same daily dose for the 3-hour prolonged infusion regimen.Conclusion: A population pharmacokinetic model of imipenem was developed for Vietnamese adult patients with severe illness. By using Monte Carlo simulation, the appropriate dose has been suggested based on the bacterial MIC value and the targeted PK/PD goal.Keywords: imipenem, pharmacokinetic modeling, PK/PD, Monte Carlo, carbapenem
- Published
- 2022
7. A robust approach to detect gas bubbles through images analysis
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T. H. Nguyen, T. L. Nguyen, Denis Sidorov, and Aliona Dreglea
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Human-Computer Interaction ,Artificial Intelligence ,Computer science ,Computer Vision and Pattern Recognition ,Software - Published
- 2020
8. Red flags to diagnose infiltrative cardiomyopathies
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E. V. Reznik, T. L. Nguyen, D. V. Ustyuzhanin, A. N. Semyachkina, and M. A. Shkolnikova
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Cardiology and Cardiovascular Medicine - Abstract
Infiltrative cardiomyopathies are a group of diseases characterized by the deposition of abnormal substances in heart tissues, which leads to thickening of the walls or dilation of chambers with a secondary decrease in wall thickness and the development of diastolic, less often systolic, ventricular dysfunction. Most often, these are progressive diseases that, in the absence of adequate therapy, have an unfavorable prognosis. Clinical manifestations of infiltrative cardiac diseases are variable, which often leads to diagnostic difficulties and errors. In most cases, specific laboratory and morphological tests are required to confirm or clarify the diagnosis. Early diagnosis is critical to initiating therapy and improving patient prognosis. This article provides characteristic signs and symptoms, the so-called "red flags", making it possible to suspect infiltrative cardiomyopathies, diagnose them at an early stage and start life-saving therapy.
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- 2023
9. Synthesis of Imidoyl Chlorides Using Phosphorus Trichloride
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Yu. V. Popov, Yu. L. Zotov, T. L. Nguyen, T. L. Q. Vo, E. V. Shishkin, and V. E. Shishkin
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chemistry.chemical_compound ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Organic chemistry ,Phosphorus trichloride ,01 natural sciences ,0104 chemical sciences ,Catalysis - Abstract
The reaction of carboxamides with phosphorus trichloride under heating at 75–80°C for 1 h in the presence of a 4-dimethylaminopyridine catalyst was used to synthesize imidoyl chlorides in yields of 63–99%.
- Published
- 2021
10. Single-cell analysis of basal cell carcinoma reveals heat shock proteins promote tumor growth in response to WNT5A-mediated inflammatory signals
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Michael L. Drummond, Christian F. Guerrero-Juarez, Rachel Y. Chow, Qing Nie, Yingzi Liu, Matthew K. Karikomi, Scott X. Atwood, Shuxiong Wang, Tuyen T. L. Nguyen, Sumaira Z. Aasi, Gun Lee, Kavita Y. Sarin, and Yutong Sha
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Tumor microenvironment ,Stromal cell ,Single-cell analysis ,Cell growth ,Chemistry ,Heat shock protein ,Signal transduction ,Hedgehog signaling pathway ,Cell biology ,Hsp70 - Abstract
How basal cell carcinoma (BCC) interacts with its tumor microenvironment to promote growth is unclear. Here we use singe-cell RNA sequencing to define the human BCC ecosystem and discriminate between normal and malignant epithelial cells. We identify spatial biomarkers of both tumors and their surrounding stroma that reinforce the heterogeneity of each tissue type. Combining pseudotime, RNA velocity, cellular entropy, and regulon analysis in stromal cells reveal a cancer-specific rewiring of fibroblasts where STAT1, TGF-β, and inflammatory signals induce a non-canonical WNT5A program that maintains the stromal inflammatory state. Cell-cell communication modeling suggests that tumors respond to the sudden burst of fibroblast-specific inflammatory signaling pathways by producing heat shock proteins, which we validated in situ. Finally, dose-dependent treatment with an HSP70 inhibitor suppresses in vitro BCC cell growth and Hedgehog signaling and in vivo tumor growth in a BCC mouse model, validating HSP70’s essential role in tumor growth and reinforcing the critical nature of tumor microenvironment crosstalk in BCC progression.
- Published
- 2021
11. Catalytic Synthesis of N-Aryladamantane-1-carboxamides Using Phosphorus Trichloride
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T. L. Nguyen, V. E. Shishkin, N. K. Sokolov, Yu. V. Popov, Yu. L. Zotov, E. V. Shishkin, and T. L. Q. Vo
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chemistry.chemical_compound ,chemistry ,010405 organic chemistry ,Organic Chemistry ,Organic chemistry ,Phosphorus trichloride ,01 natural sciences ,Triethylamine ,0104 chemical sciences ,Catalysis - Abstract
N-Aryl(benzyl)adamantane-1-carboxamides were synthesized in 54–87% yields by reaction of adamantane-1-carboxylic acid with aromatic amines in the presence of phosphorus trichloride, 4-dimethylaminopyridine, and triethylamine on heating at 80°C for 8 h.
- Published
- 2020
12. Common Skin Diseases
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Tuyen T. L. Nguyen, Scott X. Atwood, and Eric Tarapore
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medicine.medical_specialty ,business.industry ,Melanoma ,medicine ,Cancer ,Diseases skin ,Skin cancer ,medicine.disease ,business ,Dermatology - Published
- 2019
13. Hyperthermal Effect of Cubic Magnetic Nanoparticles
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Igor Shchetinin, Maxim A. Abakumov, T. L. Nguyen, T. R. Nizamov, Alexander G. Savchenko, and Alexander G. Majouga
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010302 applied physics ,Diffraction ,Materials science ,010308 nuclear & particles physics ,Hadron ,General Physics and Astronomy ,Specific absorption rate ,Nanoparticle ,equipment and supplies ,01 natural sciences ,Molecular physics ,Magnetic field ,0103 physical sciences ,Magnetic nanoparticles ,human activities - Abstract
Cubic magnetic nanoparticles with average sizes of 16.1 ± 2.2, 22.3 ± 3.5, and 37.4 ± 5.2 nm are obtained by a variety of means. The magnetic characteristics of these nanoparticles are studied as well. The samples are probed via X-ray diffraction to establish structural features, and the specific absorption rate (SAR) is analyzed as a function of the frequency and induction of an alternating magnetic field.
- Published
- 2019
14. Interaction Between Significant Adult and Toddler in Russia and Vietnam
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T V Shinina, A A Shvedovskaya, I G Morozova, T L Nguyen, E V Efremova, T H Nguyen, and I N Galasyuk
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JOINT ACTIVITY ,Social Psychology ,Developmental and Educational Psychology ,ADULT-CHILD INTERACTION ,SIGNIFICANT ADULT ,Psychology (miscellaneous) ,Toddler ,EARLY CHILDHOOD ,Psychology ,Education ,Developmental psychology - Abstract
The article discusses the role of child interaction with a significant adult (parent, kindergarten teacher, caregiver) in child’s neurocognitive development within socio-cultural contexts of Russia and Vietnam. The article presents the results of a pilot study that included focus group interviews with kindergarten specialists from Russia and Vietnam. The pilot study sample consisted of 74 participants (72 women, 2 men), aged 32 to 54 years (M = 43.04; SD = 6.61). Of these, Russian participants (10 cities) — 42 people (40 women and 2 men) aged 32 to 50 (M = 40.19; SD = 6.28) and Vietnamese participants (1 city) — 32 people (32 women) aged 38 to 54 years (M = 46.67; SD = 5.12). The interviews followed the questionnaire developed by the authors. It consisted of 21 open-ended questions grouped in 3 blocks: Block 1. What characteristics and skills should be developed during early childhood? Where and how should these be developed? Block 2. How are children under 3 years of age developed? Block 3. Who is involved in the development of a child under 3 years of age? A comparative analysis of the responses of the Russian and Vietnamese kindergarten specialists revealed no significant differences between the groups, which suggests similarities in educational and developmental strategies of young children in a kindergarten environment. © 2019 Moscow State University of Psychology& Education. The reported study was funded by RFBR and VASS, project number 19-513-92001.
- Published
- 2019
15. Favouring imperfect awareness over perfect ignorance: Response to KnightCook regarding their comment on 'Incomparability of treatment groups is often blindly ignored in randomised controlled trials - a post hoc analysis of baseline characteristic tables'
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T L, Nguyen
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- 2021
16. Generation of a maximally entangled state using collective optical pumping
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M. Malinowski, C. Zhang, V. Negnevitsky, I. Rojkov, F. Reiter, T.-L. Nguyen, M. Stadler, D. Kienzler, K. K. Mehta, and J. P. Home
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Quantum Physics ,Atomic Physics (physics.atom-ph) ,General Physics and Astronomy ,FOS: Physical sciences ,Quantum Physics (quant-ph) ,Physics - Atomic Physics - Abstract
We propose and implement a novel scheme for dissipatively pumping two qubits into a singlet Bell state. The method relies on a process of collective optical pumping to an excited level, to which all states apart from the singlet are coupled. We apply the method to deterministically entangle two trapped 40Ca+ ions. Within 16 pumping cycles, an initially separable state is transformed into one with 83(1)% singlet fidelity, and states with initial fidelity of ⪆70% converge onto a fidelity of 93(1)%. We theoretically analyze the performance and error susceptibility of the scheme and find it to be insensitive to a large class of experimentally relevant noise sources., Physical Review Letters, 128 (8), ISSN:0031-9007, ISSN:1079-7114
- Published
- 2021
- Full Text
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17. Comparative Effectiveness of Mild or Conventional GnRH-Antagonist Protocols for Ovarian Stimulation in Poor Responders (Poseidon Group 4)
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Jean-Noël Hugues, Huong T. L. Nguyen, Anh T. Cao, Hoang Le, Dung C. Tham, Dong D. Nguyen, and Thang D. Le
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0301 basic medicine ,medicine.medical_specialty ,030219 obstetrics & reproductive medicine ,business.industry ,Urology ,Antagonist ,Retrospective cohort study ,Stimulation ,03 medical and health sciences ,Follicle ,Regimen ,030104 developmental biology ,0302 clinical medicine ,Follicular phase ,Mann–Whitney U test ,medicine ,Ovarian reserve ,business - Abstract
Background and Aims: A panel of experts (the Poseidon Group) introduced a new and more detailed stratification for poor ovarian responders in order to predict the prognosis of IVF outcome according to the sensitivity to FSH. However, various arguments about the management strategy of these patients still remain, including the convenience and the cost. Therefore, this study was conducted to compare the efficacy of mild and conventional GnRH antagonist ovarian stimulation prescribed in patients classified in Poseidon Group 4.Methods: This retrospective cohort study included 359 poor responder patients (Poseidon Group 4) treated with mild or conventional GnRH antagonist stimulation regimens from 8/2017 to 7/2019 at Tam Anh Hospital ART Center. The main outcomes were the index of Follicular Output Rate (FORT) or Follicle to Oocyte Index (FOI), the number of day-2 embryos and top-quality embryos obtained. The t-test and Mann–Whitney U test in SPSS v25.0 was used to analyze the continuous data and Chi-squared/Exact test was used for binary variables. Multiple linear regression analysis was done by using Stata versions 15.0 to measure association between primary endpoints with stimulation regimen controlled for covariates and possible confounding factors.Results: In the overall group of poor responders, the conventional GnRH antagonist protocol performed better than the mild protocol. Subsequently, data were analyzed according to the AFC. In women with AFC < 3, no significant differences were observed between the 2 regimens regarding FORT (p = 0.71), FOI (p = 0.12), the number of day-2-embryos (p = 0.052) and the number of top-quality embryos (p = 0.26). In contrast, in women with AFC ≥ 3, mild stimulation regimen resulted in significantly poorer outcome compared to the conventional GnRH antagonist regimen, regarding FORT (p < 0.01), FOI (p < 0.01), the number of day-2-embryos (p < 0.01) and top-quality embryos (p = 0.01).Conclusions: Considering poor responders classified in Poseidon Group 4, both ovarian stimulation regimens resulted in similar outcome for patients with a very low ovarian reserve (AFC < 3). In contrast, the GnRH conventional antagonist protocol with maximum initial FSH dose (300–375 IU/day) and supplementary LH (75–150 IU/day) was more effective than the mild one for patients whose ovarian reserve was less reduced. The Clinical Trial was approved by the Ethnical Biomedical Research Committee Tam Anh General Hospital.
- Published
- 2020
18. aPKC drives cilia-independent Hedgehog signaling to maintain basal cell carcinoma growth
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Whitney England, Vama Jhumkhawala, Linda Doan, Kevin C. Tan, Tuyen T. L. Nguyen, Robert C. Spitale, Vinay Kumar, Ung Seop Jeon, and Scott X. Atwood
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biology ,Usher syndrome ,Cilium ,Vismodegib ,medicine.disease ,Hedgehog signaling pathway ,Cell biology ,GLI1 ,Ciliogenesis ,medicine ,biology.protein ,Basal cell carcinoma ,Hedgehog ,medicine.drug - Abstract
Primary cilia loss is a common feature of advanced cancers. While primary cilia are necessary to initiate Hedgehog (HH)-driven cancers, how HH pathway activity is maintained in advanced cancers devoid of primary cilia is unclear. Here, we find that HH-driven basal cell carcinoma (BCC) accumulate mutations in the Alström and Usher syndrome genes in advanced and SMO inhibitorresistant tumors. Loss of Alström and Usher syndrome gene expression, which are common underlying causes of deafness and blindness, suppresses ciliogenesis and HH signaling. Atypical protein kinase C iota/lambda (aPKC) is a GLI1 kinase with higher expression in advanced BCCs and we show that a constitutively active isoform drives HH pathway activity and mutually antagonizes primary cilia. Overexpression of the constitutively active aPKC variant can maintain HH pathway activity in the absence of primary cilia and can drive resistance to the SMO antagonist vismodegib regardless of cilia status. Finally, superficial BCCs display less primary cilia and higher aPKC expression, which is inversely correlated in nodular BCC subtypes. Our results suggest aPKC may serve as a biomarker for SMO inhibitor sensitivity and a target for clinical application.
- Published
- 2020
19. The potential emission of personal care products derived plastic microbeads: a case study of Ho Chi Minh City, Vietnam
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T T T Hoang, B A Nguyen, N N Q Pham, N B Nguyen, T K T Tran, T C L Tu, T D Huynh, T N T Nguyen, T P Q Pham, T V Nguyen, T L Nguyen, and Q H Le
- Abstract
Plastic microbeads are commonly used in many personal care products and can cause adverse impacts to the environment and ecosystem. The toxicological problem with these pollutants are due to their non-biodegradable materials, which washed down the drain; end up accumulating in the aquatic system causing increased frequency and quantity of items ingested by biota. Several polymers (e.g. Polyethylene) especially those found in plastic microbeads have been reported to be in tandem with other toxic contaminants serving as a vector for their transports in the environment. Thus, the legislative ban for plastic microbeads is used in some developed countries, but many countries including Vietnam do not take any legal action. This present study aimed at potential microbead’s existence in the cosmetic market of Ho Chi Minh City (HCMC). The list and ingredients of microbeads containing personal care products (toothpaste, facial cleanser/scrubs and body wash/scrubs) have been checked. The microbeads containing PCPs are common for all explored categories, especially in toothpaste. Data from the online questionnaire survey have shown that 98% of respondents have frequently used at least one microbead containing product. Four polymers (Polyethylene, Acrylates Copolymer Styrene/Acrylates Copolymer and Acrylates/C10-30 Alkyl Acrylate Crosspolymer) have been observed in the product package of several facial cleansers and body scrubs. Thus, the potential negative impacts of this contaminant should not be ignored.
- Published
- 2022
20. Effect of Magnetite Nanoparticle Morphology on the Parameters of MRI Relaxivity
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Alexander G. Majouga, Alexander G. Savchenko, T. L. Nguyen, T. R. Nizamov, M. A. Abakumov, and Igor Shchetinin
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Materials science ,General Physics and Astronomy ,Nanoparticle ,02 engineering and technology ,Coercivity ,021001 nanoscience & nanotechnology ,030218 nuclear medicine & medical imaging ,Ferumoxytol ,Condensed Matter::Materials Science ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Nuclear magnetic resonance ,Dynamic light scattering ,chemistry ,Octahedral molecular geometry ,Copolymer ,Zeta potential ,0210 nano-technology ,Magnetite - Abstract
Results are presented from synthesizing and characterizing magnetite nanoparticles with spherical, cubic and octahedral geometry. Magnetic properties (saturation magnetization, residual magnetization, and coercive force), cytotoxicity, and T2 relaxivity are measured for the synthesized nanoparticles. They are characterized via X-ray diffraction and dynamic light scattering (hydrodynamic size and zeta potential). The effect the shape of the nanoparticles have on the values of T2 relaxivity is analyzed. Nontoxic magnetite nanoparticles coated with copolymer are excellent contrast agents for magnetic resonance imaging (MRI) and show better contrast properties than their commercial analogs (Rezovist, Ferumoxytol, Feridex).
- Published
- 2018
21. Influence of Ag on the properties of Ag combined Nb-doped TiO2 (TNO) thin films deposited by a co-sputtering process
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T. H. Pham, H. L. Nguyen, C. H. Hoang, T. L. Nguyen, M. Q. Luu, Van Thanh Pham, Minh Nguyen, and N. L. H. Hoang
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Diffraction ,Materials science ,Scanning electron microscope ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,medicine.disease_cause ,01 natural sciences ,0104 chemical sciences ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Sputtering ,medicine ,symbols ,Photocatalysis ,Thin film ,0210 nano-technology ,Raman spectroscopy ,Ultraviolet ,Methylene blue - Abstract
Nb-doped TiO2 (TNO) is known as a multifunctional thin film. In this study, Ag was added to TNO thin films via a co-sputtering methodology to improve the properties of the films. X-ray diffraction, scanning electron microscopy and Raman spectroscopy were used to characterize the samples. The UV–Vis spectra indicated that the transparency of the samples decreased as the Ag content increased. The photocatalytic properties of the co-sputtered films were evaluated by photodegrading a methylene blue (MB) solution under ultraviolet (UV) radiation using back-side illumination; i.e., the UV light reaches the thin film through the Corning glass instead of the MB solution. By adding Ag into TNO films, their photocatalytic property significantly improved. The 2-min Ag-TNO film showed a maximum photocatalytic efficiency (k = 0.034 min−1) and good transparency of 70% in the visible range. Nevertheless, adding too much Ag led to a negative photocatalytic performance. The results suggested that the co-sputtering process is an efficient method to combine Ag with TNO thin films to improve their photocatalytic performance.
- Published
- 2018
22. Machine learning algorithms application to road defects classification
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Aliona Dreglea, Denis Sidorov, T. L. Nguyen, and T. H. Nguyen
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0209 industrial biotechnology ,Computer science ,business.industry ,02 engineering and technology ,Machine learning ,computer.software_genre ,Human-Computer Interaction ,020901 industrial engineering & automation ,Artificial Intelligence ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer Vision and Pattern Recognition ,Artificial intelligence ,business ,computer ,Software - Published
- 2018
23. Template-free assembly of 2D-electrolytes into nanofibres
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Hang T. L. Nguyen, Stephen J. Pennycook, Mariana C. F. Costa, Pei Rou Ng, Ricardo K. Donato, Xiaoxu Zhao, Maxim Trushin, Valeria S. Marangoni, Alexandra Carvalho, and A. H. Castro Neto
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Template free ,Materials science ,Polymers and Plastics ,Graphene ,Composite number ,Nanotechnology ,Liquid medium ,Electrolyte ,Catalysis ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,Colloid and Surface Chemistry ,Template ,law ,Drug delivery ,Materials Chemistry ,Fuel cells - Abstract
The assembly of graphene-based materials into nanofibres is of intense technological interest for numerous applications ranging from tissue engineering and drug delivery to fuel cells and space elevators. We demonstrate a composite nanofibre synthesis process using functionalised graphene structures in liquid medium (two-dimensional [2D] electrolytes) as building blocks. The approach consists in simultaneous scrolling and reacting 2D electrolytes, leading to a dimensional reduction of 2D materials into one-dimensional nanostructures. The spontaneous self-assembly and cross-linking processes allow to produce nanofibres without the need of fibrillation techniques, such as wet-spinning or external templates.
- Published
- 2021
24. Illuminating Alternative Strategies to Treat Targeted Chemotherapy-Resistant Sporadic Basal Cell Carcinoma
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Scott X. Atwood and Tuyen T. L. Nguyen
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0301 basic medicine ,Genome instability ,Skin Neoplasms ,Basal Cell Nevus Syndrome ,Mutagenesis (molecular biology technique) ,Dermatology ,Biology ,medicine.disease_cause ,Biochemistry ,Genomic Instability ,03 medical and health sciences ,Carcinoma ,medicine ,Humans ,Basal cell carcinoma ,skin and connective tissue diseases ,Molecular Biology ,Exome sequencing ,Mutation ,Cell Biology ,medicine.disease ,030104 developmental biology ,Carcinoma, Basal Cell ,Cancer research ,Smoothened - Abstract
Sporadic and basal cell nevus syndrome basal cell carcinomas show differential response rates to Smoothened inhibitors. Chiang et al. demonstrate notable decreases in UV-induced mutagenesis, total mutation load, genomic instability, and drug-resistant mutations among basal cell nevus syndrome basal cell carcinomas using whole exome sequencing, which may explain the differences in drug response rates.
- Published
- 2018
25. An Accuracy and Reliability Comparison Study of Electronic Uroflowmetry Devices
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Thinh Phuc Nguyen, Hai T. Phan, Thien M. Nguyen, Vo Van Toi, An T. L. Nguyen, and Y. L. Nguyen
- Subjects
UROFLOWMETER ,medicine.medical_specialty ,Medical diagnostic ,business.industry ,media_common.quotation_subject ,medicine.disease ,Urination ,Test (assessment) ,Informed consent ,Lower urinary tract symptoms ,medicine ,Physical therapy ,Comparison study ,business ,Reliability (statistics) ,media_common - Abstract
Uroflowmetry is a simple test measuring the volume of voided urine in a period of time. Being the only non-invasive test among urodynamic methods, it is most commonly ordered by urologists to evaluate the urination of patients, especially in males over 50 years old with lower urinary tract symptoms (LUTS). In Vietnam, however, the test is only available in urology department in large hospitals or medical diagnostic centers as it is relatively new in the field and the cost of a uroflowmeter device is still very high. Aiming to make the device more affordable to urologists and clinics and thus increase accessibility of Vietnamese patients to the test, the engineers from Biomedical Engineering Department, Ho Chi Minh International University have developed IUROF, an electronic uroflowmeter. This device allows patients to perform the uroflowmetry at home; the results and data are collected in a memory card and sent to physicians. The objective of this study is to evaluate the accuracy and reliability of IUROF by comparing it with the Andromeda Helix, a commercialized uroflowmeter device currently used in hospitals. The study was conducted at MEDIC Healthcare Center (Vietnam) in three months. A total of 40 males (57.6 ± 10.1 years of age) with LUTS were eligible and agreed to participate in the study. After signing the informed consent, the patients took turn to urinate into the IUROF and Andromeda Helix. The order of testing by the two devices altered across patients. As a result, the mean difference of Qmax was 0.05 ml/s, Qave was 0.6 ml/s, Vvoid was 0.9 ml, and tvoid was 0.2 s between the two devices. All of these differences were not statistically significant (p > 0.05). The Intra-class Correlation Coefficient (ICC) of Qmax was 0.891, showing the high level of reliability of the IUROF as compared to the Andromeda Helix. The results show that the IUROF is technically comparable to the Andromeda Helix. This has an important implication for a product developed in a university laboratory to be commercialized in the market.
- Published
- 2019
26. 2D Electrolytes: Theory, Modeling, Synthesis, and Characterization
- Author
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Hang T. L. Nguyen, Chorng H Sow, Ricardo K. Donato, Stephen J. Pennycook, Mariana C. F. Costa, Antonio H. Castro Neto, Pei Rou Ng, Xiaoxu Zhao, Sharon Xiaodai Lim, Alexandra Carvalho, Konstantin S. Novoselov, Maxim Trushin, and Valeria S. Marangoni
- Subjects
Permittivity ,Materials science ,Graphene ,Mechanical Engineering ,Ionic bonding ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Smart material ,01 natural sciences ,Polyelectrolyte ,0104 chemical sciences ,Characterization (materials science) ,law.invention ,Mechanics of Materials ,law ,Chemical physics ,General Materials Science ,Artificial muscle ,0210 nano-technology - Abstract
A class of compounds sharing the properties of 2D materials and electrolytes, namely 2D electrolytes is described theoretically and demonstrated experimentally. 2D electrolytes dissociate in different solvents, such as water, and become electrically charged. The chemical and physical properties of these compounds can be controlled by external factors, such as pH, temperature, electric permittivity of the medium, and ionic concentration. 2D electrolytes, in analogy with polyelectrolytes, present reversible morphological transitions from 2D to 1D, as a function of pH, due to the interplay of the elastic and Coulomb energies. Since these materials show stimuli-responsive behavior to the environmental conditions, 2D electrolytes can be considered as a novel class of smart materials that expand the functionalities of 2D materials and are promising for applications that require stimuli-responsive demeanor, such as drug delivery, artificial muscles, and energy storage.
- Published
- 2021
27. Beam-steering ultrasonic guided waves in a bone-mimicking plate by time-delaying the excitation of the elements in a multi-element array: a numerical study
- Author
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Haidang Phan, Quyen T. L. Bui, Hoai T. L. Nguyen, Vu-Hieu Nguyen, Kim-Cuong T. Nguyen, Lawrence H. Le, Laboratoire Modélisation et Simulation Multi-Echelle (MSME), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel, and University of Alberta
- Subjects
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph] ,Materials science ,Physics and Astronomy (miscellaneous) ,[SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging ,Phased array ,Acoustics ,0206 medical engineering ,Beam steering ,General Engineering ,General Physics and Astronomy ,02 engineering and technology ,[SPI.MECA.SOLID]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Solid mechanics [physics.class-ph] ,020601 biomedical engineering ,01 natural sciences ,Multi element ,Finite element method ,Ultrasonic guided wave ,0103 physical sciences ,Ultrasonic sensor ,010301 acoustics ,ComputingMilieux_MISCELLANEOUS ,Excitation ,Axial transmission - Abstract
We present a numerical simulation of the beam-steering of ultrasonic guided waves in an isotropic and viscoelastic solid plate, which mimics bovine cortex. The excitation was modeled by a group of five finite-size emitters, each exercised a normal force to the bone plate. Beam steering was achieved by delaying the emitters’ firing. The simulation technique was implemented by a semi-analytical finite element scheme to compute the wave fields. At small steering angles, the simulated time-offset signals show mainly two groups of arrivals. The first group is the fast-traveling and high-frequency bulk waves and the second one is slow-traveling and low-frequency guided waves. The fast-traveling waves gradually diminish with increasing steering angles, in agreement with the excitation function of the source influence theory. The frequency-phase velocity dispersion maps also illustrate the phenomenon. The study has demonstrated that the lowest order Lamb asymmetrical mode, A 0, which is useful for bone characterization, can best be excited when the cortical bone thickness is thin, the beam angle is large, and the excited frequency is low.
- Published
- 2021
28. 077 Isoform-specific aPKC maintains Hedgehog signaling in the absence of primary cilia
- Author
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Whitney England, Scott X. Atwood, Tuyen T. L. Nguyen, U. Jeon, Robert C. Spitale, V. Jhumkhawala, K. Tan, and Vinay Kumar
- Subjects
Gene isoform ,Primary (chemistry) ,Cilium ,Cell Biology ,Dermatology ,Biology ,Molecular Biology ,Biochemistry ,Hedgehog signaling pathway ,Cell biology - Published
- 2021
29. Housing and youth mental health during a COVID-19 lockdown
- Author
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J. Groot, A. Keller, A. Joensen, T.-L. Nguyen, A.-M. Nybo Andersen, and K. Strandberg-Larsen
- Subjects
Coronavirus disease 2019 (COVID-19) ,Loneliness ,Computer-assisted web interviewing ,Odds ratio ,Logistic regression ,Mental health ,language.human_language ,Danish ,Psychiatry and Mental health ,Quality of life ,language ,medicine ,medicine.symptom ,Psychology ,Demography - Abstract
IntroductionDeclines in mental health among youth in the COVID-19 pandemic have been observed, yet longitudinal studies on how housing may impact these declines are lacking.ObjectivesOur aim was to determine whether changes in mental health among Danish youth were dependent on their housing conditions.MethodsYoung participants from the Danish National Birth Cohort, who had responded to an online questionnaire at 18 years of age, and later during the initial national Danish lockdown, were included. Associations between housing conditions (direct access to outdoor spaces, urbanicity, household density, and household composition) and changes in mental health (mental well-being, quality of life (QoL) and loneliness) were examined in multivariate linear and logistic regression analyses.ResultsWe included 7455 participants. Greater decreases in mental well-being were observed for youth with no access to direct outdoor spaces and those living in denser households (mean difference -0.83 [95 % CI -1.19, -0.48], -0.30 [-0.43, -0.18], respectively). Onset of low mental well-being was associated with no access and living alone (odds ratios (OR) 1.68 [1.15, 2.47] and OR 1.47 [1.05, 2.07], respectively). Household density was negatively associated with QoL (mean difference -0.21 [-0.30, -0.12]). Youth living alone experienced more loneliness (OR 2.12 [95 % CI 1.59, 2.82]).ConclusionsHow youth’s mental health changed from before to during lockdown was associated with housing conditions. Among the Danish youth in our study, greater decreases in mental health during lockdown were observed among youth without access to outdoor spaces, living alone, or living in denser households.DisclosureNo significant relationships.
- Published
- 2021
30. Effect of pH on the adsorption behaviour of Congo Red Dye on the Mg-Al layered double hydroxide
- Author
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N A Tien, T S Do, T H L Nguyen, G V Pham, T T U Dao, D Q Nguyen Quoc, T H T Nguyen, M N Chu, and T T L Nguyen
- Subjects
chemistry.chemical_compound ,Adsorption ,chemistry ,Hydroxide ,Nuclear chemistry ,Congo red - Abstract
In the present study, the synthesis of Mg-Al layered double hydroxide at the molar ratio of 3:1 for Mg/Al are determined. One-step hydrothermal technique with slow hydrolysis of urea at a low temperature was employed without further annealing. The study was aimed at determining the effectiveness of Congo Red dye removal in the adsorption process onto Mg-Al layered double hydroxide (LDH) with respect to the change in pH of the solution. The experiment was conducted at concentrations of a sorbent 0.04g with 100 ml of Congo Red and at six values of the reaction, i.e. pH 2.0, pH 4.0, pH 6.0, pH 8.0, pH 10, and pH 12.0. It was found that pH affects the adsorbent surface charge and the degree of anionic dye dissociation. This can be explained to the chemical form of dye in the solution and functional groups present on the adsorbent surface at a specific pH.
- Published
- 2020
31. Optimal design of vehicle structure for improving small-overlap rating
- Author
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H. J. Yim, P. T. L. Nguyen, Seung-Jin Heo, Seang-Wock Lee, Heung-Kyu Kim, and Jung-Sug Lee
- Subjects
Optimal design ,Engineering ,Crash simulation ,business.industry ,Automotive Engineering ,Structure (category theory) ,Crashworthiness ,Crash analysis ,Structural engineering ,Function (mathematics) ,business ,Reinforcement ,Crash test - Abstract
This paper presents a study on the optimal design of vehicle structure for improving the small-overlap rating, based on a computer-based crash simulation model. Two reinforced component models such as longitudinal reinforcement and rocker panel reinforcement were developed for the small-overlap frontal impact simulation following the real test conditions. The crash simulation results were used to evaluate the overall vehicle structure through a comparison of intrusion measurements with the rating guidelines of the Insurance Institute for Highway Safety. The response surface method (RSM) was conducted to optimal vehicle structures in order to improve the small-overlap rating. The RSM function proposed the optimal values of the variables as the new design. The crash analysis results showed that the serious damage to the vehicle structure occurred when the minivan model collided with barrier model at 25% overlap. In this study, the grade of the overall structure was upgraded from “poor” to “acceptable” in the case of Flat 150 (the Flat barrier with a 150 mm radius and 25% overlap).
- Published
- 2015
32. Analysis of vehicle structural performance during small-overlap frontal impact
- Author
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H. J. Yim, P. T. L. Nguyen, Sang Beom Lee, Seung-Jin Heo, and Jung-Sug Lee
- Subjects
Engineering ,Crash simulation ,business.industry ,Hinge ,Poison control ,Traffic simulation ,Crash ,Structural engineering ,Crash test ,Automotive engineering ,Finite element method ,Automotive Engineering ,Crashworthiness ,business - Abstract
This paper presents an analysis of the vehicle structural performance in the event of a small-overlap frontal impact (SOFI), based on a computer-based crash simulation model. The vehicle model was used for SOFI simulation according to real small-overlap test conditions. The crash simulation results were used to evaluate the overall vehicle structure through a comparison of intrusion measurements with the rating guidelines of the Insurance Institute for Highway Safety. The parts sensitive to a small-overlap crash were confirmed. Thickness optimization was conducted to strengthen the rocker panel, A-pillar, and lower hinge pillar in order to improve the vehicle structural performance in the event of a SOFI. The best values among the variables were chosen for the new design. The crash analysis using finite element models showed that the most serious deformation occurred to the A-pillar. In this study, the grade of the overall structure was changed from “poor” to “marginal”.
- Published
- 2015
33. Corifollitropin alfa vs recombinant FSH for controlled ovarian stimulation in women aged 35-42 years with a body weight ≥50 kg: a randomized controlled trial
- Author
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G B Huynh, H T Phung, Manh Tuong Ho, N L Vuong, T T L Nguyen, H N Giang, and D T Pham
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Randomization ,media_common.quotation_subject ,Ovarian hyperstimulation syndrome ,Controlled ovarian hyperstimulation ,controlled ovarian stimulation ,recombinant FSH ,ICSI ,live birth ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,law ,medicine ,Menstrual cycle ,media_common ,Pregnancy ,030219 obstetrics & reproductive medicine ,Obstetrics ,business.industry ,corifollitropin alfa ,medicine.disease ,Embryo transfer ,follitropin beta ,030104 developmental biology ,IVF ,Physical therapy ,Original Article ,pregnancy ,Live birth ,business - Abstract
Study question Is corifollitropin alfa 150 μg equivalent to follitropin beta 300 IU/day for controlled ovarian hyperstimulation (COS) in older women weighing ≥50 kg undergoing IVF and/or ICSI in Vietnam? Summary answer Corifollitropin alfa 150 μg was equivalent to follitropin beta 300 IU/day with respect to the number of oocytes retrieved, the ongoing, cumulative and live birth rates and obstetric outcomes. What is known already Corifollitropin alfa is a recombinant FSH (rFSH) preparation with slow absorption and a long half-life allowing administration of a single dose for COS lasting 7 days. Several randomized, controlled clinical trials have reported that COS with corifollitropin alfa is associated with similar outcomes compared with COS using daily rFSH. However, limited data are available in Asian patients. Study design size duration This randomized controlled trial was conducted at a single large IVF centre in Vietnam from June 2015 to August 2016. A total of 400 patients were included, 200 in each treatment group. The primary outcome measure was the number of oocytes retrieved. Patients were followed for 1 year after randomization. Participants /materials setting methods Participants aged 35-42 years with a body weight ≥50 kg who were undergoing an IVF cycle were randomized to undergo COS with a single dose of corifollitropin alfa 150 μg on Day 2 or 3 of the menstrual cycle, or follitropin beta 300 IU/day for 7 days starting on Day 2 or 3 of the menstrual cycle. All underwent ICSI according to standard institutional protocols. A beta hCG test was performed 17 days after ovum pick-up, and positive tests were confirmed on vaginal and/or abdominal ultrasound at 5-6 weeks after embryo transfer (clinical pregnancy) and at ≥10 weeks (ongoing pregnancy). Rates of ovarian hyperstimulation syndrome, and maternal and foetal outcomes after one cycle of ICSI were monitored over 12 months. Main results and the role of chance Patients in the corifollitropin alfa and follitropin beta groups were well matched at baseline (mean age 37.5 ± 1.9 vs 37.7 ± 2.0 years, mean body weight 53.7 ± 5.4 vs 52.5 ± 4.8 kg). There was no significant difference between the corifollitropin alfa and follitropin beta groups in the number of oocytes retrieved (11.4 ± 5.9 vs 10.8 ± 5.8; P = 0.338). The ongoing pregnancy rate (31.5 vs 32.0%; P = 0.99) and live birth rate (30.5 vs 32.0%; P = 0.83) (both per initiated cycle at 12 months after randomization) were also similar in the two treatment groups. Complication rates were low and similar in the corifollitropin alfa and follitropin beta groups, and there were no significant between-group differences in obstetric outcomes. Limitations reasons for caution This study had an open-label design, and therefore, the potential for bias cannot be excluded. The findings are only applicable to patient populations with similar characteristics to those enroled in the study. Wider implications of the findings This study adds to the body of evidence supporting the equivalence of corifollitropin alfa and follitropin beta for COS in a variety of patients undergoing IVF and/or ICSI. The ability to provide COS with corifollitropin alfa has the potential to reduce the burden of treatment for patients. Study funding/competing interests This study was supported by Merck Sharp and Dohme. The authors state that they have no financial or commercial conflicts of interest. Trial registration number The trial was registered with clinicaltrials.gov (NCT02466204). Trial registration date 2 June 2015. Date of first patient’s enrolment 19 June 2015.
- Published
- 2017
34. Characterization of enhancers and the role of the transcription factor KLF7 in regulating corneal epithelial differentiation
- Author
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William K. Hu, Ghaidaa Kashgari, Ziguang Lin, Michael Doan, Tuyen T. L. Nguyen, Bogi Andersen, and Rachel Herndon Klein
- Subjects
0301 basic medicine ,superenhancer ,Cellular differentiation ,Regenerative Medicine ,Biochemistry ,Medical and Health Sciences ,Epithelium ,Corneal Diseases ,Histones ,Stem Cell Research - Nonembryonic - Human ,2.1 Biological and endogenous factors ,Aetiology ,Corneal epithelium ,corneal epithelium ,Stem Cells ,Epithelium, Corneal ,Acetylation ,Cell Differentiation ,Single Nucleotide ,Biological Sciences ,eye ,KLF7 ,Cell biology ,medicine.anatomical_structure ,Enhancer Elements, Genetic ,KLF4 ,Biochemistry & Molecular Biology ,Chromatin Immunoprecipitation ,Enhancer Elements ,1.1 Normal biological development and functioning ,Kruppel-Like Transcription Factors ,Biology ,Polymorphism, Single Nucleotide ,Cell Line ,03 medical and health sciences ,Histone H3 ,Kruppel-Like Factor 4 ,Genetic ,Underpinning research ,medicine ,Genetics ,Humans ,Gene Regulation ,Polymorphism ,Enhancer ,Molecular Biology ,Eye Disease and Disorders of Vision ,030102 biochemistry & molecular biology ,epithelial cell ,Human Genome ,Corneal ,Cell Biology ,Stem Cell Research ,030104 developmental biology ,cell proliferation ,Gene Expression Regulation ,Chemical Sciences ,H3K4me3 ,chromatin ,Generic health relevance ,sense organs ,gene regulation ,Chromatin immunoprecipitation - Abstract
During tissue development, transcription factors bind regulatory DNA regions called enhancers, often located at great distances from the genes they regulate, to control gene expression. The enhancer landscape during embryonic stem cell differentiation has been well characterized. By contrast, little is known about the shared and unique enhancer regulatory mechanisms in different ectodermally derived epithelial cells. Here we use ChIP sequencing (ChIP-seq) to identify domains enriched for the histone marks histone H3 lysine 4 trimethylation, histone H3 lysine 4 monomethylation, and histone H3 lysine 27 acetylation (H3K4me3, H3K4me1, and H3K27ac) and define, for the first time, the super enhancers and typical enhancers active in primary human corneal epithelial cells. We show that regulatory regions are often shared between cell types of the ectodermal lineage and that corneal epithelial super enhancers are already marked as potential regulatory domains in embryonic stem cells. Kruppel-like factor (KLF) motifs were enriched in corneal epithelial enhancers, consistent with the important roles of KLF4 and KLF5 in promoting corneal epithelial differentiation. We now show that the Kruppel family member KLF7 promotes the corneal progenitor cell state; on many genes, KLF7 antagonized the corneal differentiation-promoting KLF4. Furthermore, we found that two SNPs linked previously to corneal diseases, astigmatism, and Stevens-Johnson syndrome fall within corneal epithelial enhancers and alter their activity by disrupting transcription factor motifs that overlap these SNPs. Taken together, our work defines regulatory enhancers in corneal epithelial cells, highlights global gene-regulatory relationships shared among different epithelial cells, identifies a role for KLF7 as a KLF4 antagonist in corneal epithelial cell differentiation, and explains how two SNPs may contribute to corneal diseases.
- Published
- 2017
35. BREEDING OF TOMATO (LYCOPERSICON ESCULENTUM) RESISTANT TO TOMATO SPOTTED WILT VIRUS
- Author
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G. F. Monakhos, T. L. Nguyen, and M. L. Nguyen
- Subjects
molecular marker ,Germplasm ,fungi ,food and beverages ,Agriculture ,tomato ,Biology ,Crop ,Horticulture ,chemistry.chemical_compound ,chemistry ,tomato spotted wilt virus ,Molecular marker ,lycopersicon esculentum ,Botany ,Genotype ,allele sw5 ,Allele ,Tomato spotted wilt virus ,Genotyping ,Gene - Abstract
The results of tomato lines resistance test to tomato spotted wilt virus and its comparison to molecular marker SCAR Sw421 genotyping data is shown. A molecular marker SCAR Sw421 analysis allowed identifying homozygous and heterozygous tomato genotypes possessing Sw5 alleles in segregating populations. Selected tomato lines possessing dominant homozygous alleles of Sw5 gene represent a tomato germplasm resistant to tomato spotted wilt virus and would be useful for following crop improvement.
- Published
- 2014
36. RARβ2 is required for vertebrate somitogenesis
- Author
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Weiyi Tang, Amanda Janesick, Tuyen T. L. Nguyen, and Bruce Blumberg
- Subjects
0301 basic medicine ,Embryo, Nonmammalian ,Receptors, Retinoic Acid ,TBX6 ,Retinoic acid ,Embryonic Development ,Tretinoin ,Biology ,Xenopus Proteins ,Benzoates ,Models, Biological ,Morpholinos ,Mesoderm ,03 medical and health sciences ,chemistry.chemical_compound ,Retinoids ,Xenopus laevis ,Myotome ,Somitogenesis ,medicine ,Paraxial mesoderm ,Animals ,Protein Isoforms ,Myoblast migration ,Promoter Regions, Genetic ,Molecular Biology ,Muscles ,Retinoic Acid Receptor alpha ,Clock and wavefront model ,Gene Expression Regulation, Developmental ,Anatomy ,Cell biology ,Somite ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Somites ,Larva ,Biomarkers ,Developmental Biology - Abstract
During vertebrate somitogenesis, retinoic acid is known to establish the position of the determination wavefront, controlling where new somites are permitted to form along the anteroposterior body axis. Less is understood about how RAR regulates somite patterning, rostral-caudal boundary setting, specialization of myotome subdivisions, or the specific RAR subtype that is required for somite patterning. Characterizing the function of RARβ has been challenging due to the absence of embryonic phenotypes in murine loss-of-function studies. Using the Xenopus system, we show that RARβ2 plays a specific role in somite number and size, restriction of the presomitic mesoderm anterior border, somite chevron morphology and hypaxial myoblast migration. Rarβ2 is the RAR subtype whose expression is most up-regulated in response to ligand and its localization in the trunk somites positions it at the right time and place to respond to embryonic retinoid levels during somitogenesis. RARβ2 positively regulates Tbx3 a marker of hypaxial muscle, and negatively regulates Tbx6 via Ripply2 to restrict the anterior boundaries of the presomitic mesoderm and caudal progenitor pool. These results demonstrate for the first time an early and essential role for RARβ2 in vertebrate somitogenesis.
- Published
- 2016
37. Position control and vibration suppression of a flexible overhead crane system
- Author
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M. D. Duong and T. L. Nguyen
- Subjects
Vibration ,Engineering ,business.industry ,Control theory ,Overhead crane ,business ,Position control ,Simulation - Published
- 2016
38. Inhibition of DYRK1A overdosage restores cognition in Down syndrome models through DYRK1A-interaction with major players of synaptic transmission
- Author
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François Carreaux, Yann Herault, Jean Pierre Bazureau, A. Manousopoulou, Laurent Meijer, Arnaud Duchon, T. L. Nguyen, E. Limanton, and S.D. Garbis
- Subjects
Pharmacology ,Down syndrome ,DYRK1A ,Cognition ,Neurotransmission ,medicine.disease ,Psychiatry and Mental health ,Neurology ,medicine ,Pharmacology (medical) ,Neurology (clinical) ,Psychology ,Neuroscience ,Biological Psychiatry - Published
- 2017
39. Social work and policy transfer: Reflections on introducing vocational qualifications in Vietnam
- Author
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Irene Stevens, Raymond Taylor, and T. T. L. Nguyen
- Subjects
Focus (computing) ,Policy transfer ,Sociology and Political Science ,Social work ,business.industry ,Vocational education ,Political science ,Pedagogy ,Public relations ,business ,Social Sciences (miscellaneous) - Abstract
This paper compares contemporary developments in social work in Vietnam with the United Kingdom (UK). Three areas of comparison form the focus of the paper: the role of the paraprofessional, the potential of vocational education and the different expectations of social work in the 21st century.
- Published
- 2011
40. Ontologie des interventions non médicamenteuses
- Author
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T.-L. Nguyen, Grégory Ninot, F. Carbonnel, A. Gérazine, and E. Guerdoux-Ninot
- Subjects
Epidemiology ,Public Health, Environmental and Occupational Health - Abstract
Introduction Les professionnels de sante et les patients recourent de plus en plus aux interventions non pharmacologiques regroupees en France sous l’appellation generique interventions non medicamenteuses (INM). Il peut s’agir de methodes psychologiques, corporelle, manuelle, numerique, nutritionnelle, ou phytotherapique. On constate dans la litterature des difficultes pour identifier les etudes evaluant leurs benefices/risques en particulier a cause d’une description insuffisante de leur contenu par leurs auteurs. La construction d’une ontologie des INM associant une designation, un contenu, une theorie mecanistique, un objectif sante, une population cible et un contexte d’utilisation est a ce jour indispensable pour mieux identifier les etudes notamment pour faciliter la realisation de meta-analyses. Methodes Dans un premier temps, la construction d’une ontologie racine mentionnant les termes vedettes a ete realisee par des professionnels de la sante et des patients. Dans un second temps, ces professionnels et ces patients ont propose la liste la plus exhaustive possible des synonymes en anglais et en francais. Dans un troisieme temps, un systeme de fouille de donnees automatiques a partir des bases de donnees Pubmed, UMLS et Bioportal a ete realise afin de completer la base de donnees. Dans un quatrieme temps, un groupe d’experts et de patients ont valide ou invalide les mots obtenus et ainsi enrichi la classification des termes associes et des synonymes. Dans un cinquieme temps, un site collaboratif a ete cree afin de partager cette ontologie et permettre un meilleur enrichissement et un developpement multilingue. Resultats Une liste exhaustive de ces termes a ete constituee, validee et ensuite classee par categorie et sous-categorie par des groupes d’experts dans chacune de ces categories ainsi que par les membres de la plateforme CEPS. Cette liste sera ensuite diffusee en ligne pour etre completee de maniere iterative. Discussion/Conclusion La finalite de ces recherches est de permettre une meilleure identification et citation des etudes interventionnelles sur les INM, ce qui facilitera la recherche bibliographique pour toute revue systematique ou nouvelle etude interventionnelle.
- Published
- 2018
41. Surface Plasmon Mediated Strong Exciton−Photon Coupling in Semiconductor Nanocrystals
- Author
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Paul Mulvaney, T. L. Nguyen, Timothy J. Davis, K. C. Vernon, and Daniel E. Gómez
- Subjects
Silver ,Materials science ,Exciton ,Physics::Optics ,Bioengineering ,Substrate (electronics) ,Condensed Matter::Materials Science ,Planar ,Quantum Dots ,Cadmium Compounds ,Electrochemistry ,Physics::Atomic and Molecular Clusters ,Nanotechnology ,General Materials Science ,Colloids ,Selenium Compounds ,Plasmon ,Coupling ,Photons ,Condensed matter physics ,Condensed Matter::Other ,Mechanical Engineering ,Surface plasmon ,Temperature ,Cavity quantum electrodynamics ,General Chemistry ,Surface Plasmon Resonance ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Nanostructures ,Semiconductors ,Excited state ,Nanoparticles ,Crystallization - Abstract
We present an experimental demonstration of strong coupling between a surface plasmon propagating on a planar silver substrate, and the lowest excited state of CdSe nanocrystals. Variable-angle spectroscopic ellipsometry measurements demonstrated the formation of plasmon-exciton mixed states, characterized by a Rabi splitting of $\sim$ 82 meV at room temperature. Such a coherent interaction has the potential for the development of plasmonic non-linear devices, and furthermore, this system is akin to those studied in cavity quantum electrodynamics, thus offering the possibility to study the regime of strong light-matter coupling in semiconductor nanocrystals at easily accessible experimental conditions.
- Published
- 2009
42. Polarisation to colour transformation via nano-antenna enhanced quantum dot emission
- Author
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Ann Roberts, T. L. Nguyen, Paul Mulvaney, Timothy J. Davis, Evgeniy Panchenko, and Timothy D. James
- Subjects
Photoluminescence ,Materials science ,business.industry ,Physics::Optics ,Optical polarization ,Polarization (waves) ,Optics ,Semiconductor ,Quantum dot laser ,Quantum dot ,Electro-absorption modulator ,Optoelectronics ,business ,Plasmon - Abstract
Metallic nano-antennas have been shown to be an excellent candidate for enhancing and directing optical emission from semiconductor based quantum dots (QD). QD photoluminescence (PL) enhancement is achieved by placing a suitably orientated QD in the near-field of a resonant metallic nano-antenna. Through the careful design of an optical Vee-antenna, two distinct visible resonances can be obtained, enabling the polarization dependant enhancement of two different QD sources, thus producing a polarization-to-colour transformation at the nano-scale. Possible future applications include an optical nano-scale demultiplexer device.
- Published
- 2014
43. Fabrication and Characterization of Anode Supported Tubular SOFCs with Zirconia Based Electrolyte for Reduced Temperature Operation
- Author
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K. Hosoda, T. L. Nguyen, T. Honda, M. Dokiya, A. Kobayashi, T. Kato, Z. Cai, and M. Shiono
- Subjects
Fabrication ,Materials science ,Chemical engineering ,law ,Cubic zirconia ,Electrolyte ,Substrate (electronics) ,Porosity ,Dip-coating ,Cathode ,law.invention ,Anode - Abstract
An anode supported tubular solid oxide fuel cell (SOFC) with a thin electrolyte film for reduced temperature operation was fabricated by a wet co-fire process. Instead of the traditional extrusion method, the anode substrate was formed by a tape cast method. This allows designing the substrate with some advantageous configurations that can improve the performance of SOFCs. Y 2 O 3 and Sc 2 O 3 stabilized zirconia electrolyte films were fabricated on the substrate by a modified slurry dip coating technique, and then co-fired. By combining with (CeGd)O 2 interlayer, (La 0.6 Sr 0.4 )CoO 3 cathode was used. The fabricated tubular cell successfully generated electricity between 600-850°C. However, the bulk resistance was larger than expected. Since (CeGd)O 2 interlayer was used, bulk resistance could be high due to the formation of some insulating phases at the zirconia/ceria interface. The diffusion resistance governed the performance between 700-850°C. Further optimization of the zirconia/ceria interface and control of both porosity and thickness of the anode substrate are key factors for realizing this type of co-fired anode substrate SOFCs.
- Published
- 2003
44. Induction and decline of hepatic cytochromes P4501A1 and 1A2 in rats exposed to hyperoxia are not paralleled by changes in glutathione S-transferase-α
- Author
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Stephen E. Welty, Kerry D Stewart, Sanjiv Gupta, Uyen T.-L Nguyen, Charles V. Smith, and Bhagavatula Moorthy
- Subjects
Male ,medicine.medical_specialty ,Hyperoxia ,Toxicology ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Cytochrome P-450 CYP1A2 ,Internal medicine ,Cytochrome P-450 CYP1A1 ,medicine ,Animals ,Enzyme inducer ,Glutathione Transferase ,biology ,CYP1A2 ,Cytochrome P450 ,General Medicine ,Glutathione ,respiratory system ,Pulmonary edema ,medicine.disease ,Rats ,Endocrinology ,Glutathione S-transferase ,chemistry ,Enzyme Induction ,Toxicity ,Microsomes, Liver ,biology.protein ,medicine.symptom - Abstract
We investigated the effects of hyperoxia on the activities of hepatic ethoxyresorufin O-deethylase (EROD) (CYP1A1), methoxyresorufin O-demethylase (MROD) (CYP1A2), and glutathione transferase-alpha (GST-alpha), and the status of protein thiols (PSH) in male Sprague-Dawley rats. Twenty-four h of hyperoxia more than doubled EROD and MROD activities, which were increased 7.6- and 3.3-fold, respectively, after 48 h of hyperoxia. The increases in EROD and MROD activities were paralleled by enhanced CYP1A1/1A2 apoproteins contents, as detected by Western analysis. At 60 h of hyperoxia, by which time hyperoxic Sprague-Dawley rats display marked respiratory distress, pulmonary edema, and other markers of pulmonary dysfunction, the activities and levels of hepatic CYP1A1 and 1A2 had declined dramatically and returned to levels observed in air-breathing control animals. Hepatic activities of GST-alpha, as well as PSH status, were not altered significantly in the hyperoxic animals at any time point. The marked induction and subsequent decline of hepatic CYP1A1/1A2 activities in rats exposed to hyperoxia suggest that these enzymes may contribute to the mechanisms of injury and/or to adaptive responses to hyperoxic exposures in vivo.
- Published
- 1997
45. Antibiotic therapy for inpatients with community-acquired pneumonia in a developing country
- Author
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Hieu T, Trinh, Phuong H, Hoang, Magnolia, Cardona-Morrell, Hai T, Nguyen, Dinh Hoa, Vu, Phuong T X, Dong, Thao T B, Cao, Son T, Nguyen, Van T T, Pham, Le, Moss, Kathryn, Dinh, Jonathan, Dartnell, and Huong T L, Nguyen
- Subjects
Community-Acquired Infections ,Male ,Vietnam ,Pneumonia, Bacterial ,Humans ,Female ,Middle Aged ,Developing Countries ,Anti-Bacterial Agents ,Retrospective Studies - Abstract
The aim of this study was to identify antibiotic prescription patterns for community-acquired pneumonia (CAP) in Vietnam.Medical records for CAP adult patients admitted to 10 hospitals across the country were randomly selected from admission lists during the peak pneumonia season. CAP cases were identified from manual record reviews by clinical pharmacists. Data was collected using a standard data collection tool including patient clinical features on admission, comorbidities, microbiological culture results, and antibiotic regimens. Pneumonia severity was estimated using the CURB-65 score.A total of 649 medical records for adult patients (55.2% male and 52.3% urban residents, median age 68 years) met the selection criteria for CAP. Pneumonia severity was assessed as mild (64.1% of patients), moderate (23.0%), and severe (9.2%). Antibiotics were most frequently administered intravenously (93.4%) and as combination therapy (dual therapy 54.4%, monotherapy 42.5%, and triple therapy 3.1% of patients) regardless of CAP severity. Third-generation cephalosporins were used most frequently (29.3% as monotherapy and 40.4% as combination therapy). Third-generation cephalosporins were most commonly combined with penicillins and/or quinolones.This first nationwide study provides a baseline profile of antibiotic use in the treatment of CAP. Third-generation cephalosporins were widely used for initial empirical management of CAP, often in combination with quinolones, regardless of CAP severity. The study will assist in providing an evidence base to inform new national antibiotic guidelines for CAP management and will contribute locally relevant data for the national master plan addressing antibiotic resistance and the development of educational interventions to improve CAP management.
- Published
- 2013
46. Activité biologique de dérivés 2,3-naphtalocyanines de silicium comme sensibilisateurs potentiels en photochimiothérapie du cancer
- Author
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N. Brasseur, R. Langlois, D. Houde, J. E. Van Lier, R. Ouellet, S. Marengo, and T. L. Nguyen
- Subjects
Biochemistry - Abstract
La photochimiotherapie (PCT) du cancer repose sur l'activation par la lumiere rouge d'agents photosensibilisants du type des porphyrines, qui sont retenus preferentiellement par les tissus tumoraux apres leur administration systemique. Au cours des dernieres annees, plusieurs classes de composes ont ete proposes comme nouveaux photosensibilisateurs. Parmi eux, les naphtalocyanines presentent l'avantage d'une absorption elevee vers 780 nm, ou la transmission de la lumiere par les tissus est maximale. Nous avons donc prepare quatre derives 2,3-naphtalocyanines de silicium, substitues axialement avec deux chaines siloxy-alkyles de longueur croissante
- Published
- 1994
47. Mesure du rendement d'oxygène singulet généré à partir de photosensibilisateurs tumoraux à base de naphtalocyanines
- Author
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S. Marengo, T. L. Nguyen, J. E. Van Lier, D. Houde, N. Brasseur, and R. Ouellet
- Subjects
Biochemistry - Abstract
Notre etude porte sur les photosensibilisateurs suivants: bis-(tri-n-hexylsiloxy) (compose I), bis(dimethyloctadecylsiloxy) (II), bis-(dimethylthexylsiloxy) (III), bis(tert-butyldimethylsiloxy) (IV) 2,3-naphtalocyanine de silicium (SiNc) et 2,3-naphtalocyanine de zinc (ZnNc) (V). Une methode d'etalonnage, pour obtenir le rendement quantique d'oxygene singulet ( 1 O 2 ), a ete developpee avec l'utilisation d'un capteur de 1 O 2 , le 9,10-diphenylanthracene (DPA). Nous avons ainsi calcule des rendements quantiques de 1 O 2 . Les valeurs suivantes ont ete obtenues: pour le compose I, Φ=0,38; pour le II, Φ=0,39; pour le III, Φ=0,39 et pour le IV, Φ=0,22
- Published
- 1994
48. Gastrodia elata bl attenuates methamphetamine-induced dopaminergic toxicity via inhibiting oxidative burdens
- Author
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C.G Jang, B.-D Jung, J.-H Bach, S.K Ko, T.-T. L Nguyen, X.-K. T Nguyen, Eun-Joo Shin, S. F Ali, K.-W Oh, H.-C Kim, and M. J Kim
- Subjects
Pharmacology ,medicine.disease_cause ,Protein oxidation ,Article ,Lipid peroxidation ,chemistry.chemical_compound ,medicine ,Pharmacology (medical) ,Gastrodia elata Bl ,methamphetamine ,Tyrosine hydroxylase ,biology ,business.industry ,Dopaminergic ,General Medicine ,Methamphetamine ,biology.organism_classification ,Malondialdehyde ,oxidative stress ,Gastrodia elata ,Psychiatry and Mental health ,Neurology ,chemistry ,Neurology (clinical) ,dopamine ,business ,Neuroscience ,Oxidative stress ,medicine.drug - Abstract
It has been recognized that Gastrodia elata Bl (GE), an oriental herb medicine, ameliorates various neurological disorders, that GE modulates the monoaminergic and GABAergic systems, and that GE possess antioxidant activities. We examined whether GE affects methamphetamine (MA)-induced striatal dopaminergic toxicity in mice. Treatment with MA (7.5 mg/kg, i.p. × 4) resulted in significant decreases in behavioural activity (as shown by locomotor activity and rota rod performance), dopamine level, tyrosine hydroxylase (TH) activity, and TH protein expression (as evaluated by immunocytochemistry and western blot analysis). In addition, MA treatment showed significant increases in lipid peroxidation [as evaluated by 4-hydroxy-2-nonenal (4-HNE) expression and malondialdehyde formation], protein oxidation (as shown by protein carbonyl expression and its formation), and reactive oxygen species (ROS) formation. Treatment with GE significantly attenuates MA-induced behavioural and dopaminergic impairments, and oxidative stresses in a dose-dependent manner. Our results suggest that GE treatment shows anti-dopaminergic effects in response to MA insult via, at least in part, inhibiting oxidative stresses in the striatum of the mice.
- Published
- 2009
49. 153 The 15 m Shuttle Test is a valuable alternative to conventional shuttle tests in some CF patients
- Author
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Christian Opdekamp, Christiane Knoop, V. Gaspar, Laurence Hanssens, O. Van Hove, T.-L. Nguyen, A. Van Muylem, and Georges Casimir
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,business.industry ,Internal medicine ,Pediatrics, Perinatology and Child Health ,Heart rate ,Cardiology ,Medicine ,In patient ,Shuttle test ,Exercise capacity ,business - Abstract
Background There are several tests available for the long-term evaluation of exercise capacity. Of these tests, the 10 m and 20 m Shuttle Tests can be performed in CF patients but they may be either too short or too long in patients who are doing fine or who are very ill, respectively. The aim of this study was to assess the feasibility of a 15 m Shuttle Test (15MST) in CF children, adults and lung transplant recipients (LTR). Methods and Patients Forty-one stable patients performed a 15MST: 19 CF children (FEV1 83±13% pred), 16 CF adults (FEV1 67±23%) and 6 LTR (FEV1 83±14%). Results In CF children, level variability (LV) was between 4 and 12, performed distance was 654±253 m, extrapolated VO 2 max (eVO 2 max) was 43±3 ml/kg/min, heart rate (HR) was 133±15 bpm, SaO 2 was 97±1% and dyspnea score (Borg Scale) was 5±3. In CF adults, LV was between 2 and 10, performed distance 611±334 m, eVO 2 max 30±6 ml/kg/min, HR 159±17 bpm, SaO 2 89±6% and dyspnea score 8±1. In LTR, LV was between 2 and 5, performed distance 330±117 m, eVO 2 max 20±13 ml/kg/min, HR 140±14 bpm, SaO 2 96±1% and dyspnea score 8±1. Conclusion The 15MST is feasible and usable in CF children and adults as well as LTR patients. It can be an alternative to 10 m and 20 m Shuttle Tests but it must still be validated. This work was supported by a grant from the Belgian Cystic Fibrosis Association and is part of our educational project ‘Just move it! move it!'.
- Published
- 2015
50. Vascular endothelial dysfunction contributes to myocardial depression in ischemia-reperfusion in the rat
- Author
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X L, Qi, T L, Nguyen, L, Andries, S U, Sys, and J L, Rouleau
- Subjects
Microscopy, Confocal ,Octoxynol ,Myocardium ,Myocardial Reperfusion Injury ,In Vitro Techniques ,Papillary Muscles ,Myocardial Contraction ,Muscle, Smooth, Vascular ,Rats ,Vasodilation ,Animals ,Calcium ,Endothelium, Vascular ,Rats, Wistar ,Creatine Kinase ,Endocardium ,Muscle Contraction - Abstract
Endocardial and vascular myocardial capillary endothelium has been shown to modulate the contractile characteristics of myocardium by altering myofibrillar affinity for calcium. Although the release of endothelial-derived substances that modify myocardial contractility has been shown to be altered in certain physiologic and pathologic situations, until now no study has evaluated whether the direct modulatory effects of endothelium on its subjacent myocardium were altered in pathologic situations and contributed to loss of contractile function. This study was designed to evaluate whether the direct contractile modulatory effects of endocardial and (or) vascular endothelium were altered and whether these alterations contributed to contractile dysfunction in a model of ischemia-reperfusion. Sixty-two perfused rat hearts as Langendorff preparations were randomized to no intervention, intracoronary Triton X100 injection (to render vascular endothelium dysfunctional), ischemia (30 min)-reperfusion (20 min), and ischemia-reperfusion followed by intracoronary Triton X100 injection. Coronary endothelial-dependent vascular reactivity and vascular smooth muscle reactivity were assessed by serotonin and sodium nitroprusside, respectively. Myocardial damage was assessed by coronary effluent creatine phosphokinase and by morphologic studies. Papillary muscles were then excised and contractile characteristics evaluated at varying extracellular calcium concentration prior to and after endocardial endothelial removal with Triton X100. All three interventions eliminated all coronary vascular response to serotonin but did not modify response to nitroprusside. Creatine phosphokinase values rose only in hearts with ischemia-reperfusion, and only minor morphologic changes occurred, mostly in hearts with ischemia-reperfusion. Papillary muscles from hearts with intracoronary Triton X100 injection had lower contractile indices compared with normal controls (total tension 4.0 vs. 4.6 g/mm2, p0.01) and an abbreviation of contraction duration. Increasing extracellular calcium concentration from to 0.7 to 3.25 mM eliminated these differences. Similar but more marked decreases in contractile indices and twitch duration were noted in the two ischemia-reperfusion groups, but consistent with some myocardial damage being present, increasing extracellular calcium concentration to 3.25 or 7 mM did not fully eliminate these differences. In both ischemia-reperfusion groups and the intracoronary Triton X100 group, the relative increase in total tension with increasing extracellular calcium concentrations was similar (35 to 38%) and greater than that of the control group (25%), consistent with dysfunction of vascular endothelium contributing to myocardial dysfunction in the three intervention groups. Endocardial endothelial removal had a similar effect in all four groups, suggesting that dysfunction of endocardial endothelium does not play a role in this model. We conclude that vascular but not endocardial endothelial dysfunction contributes to the myocardial dysfunction that occurs during ischemia-reperfusion injury.
- Published
- 1998
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