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Search Results: 1 - 10 of 37323 matches for " Nguyen Van Nhien "
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Click Reactions as a Key Step for an Efficient and Selective Synthesis of D-Xylose-Based ILs
Nadège Ferlin,Sylvain Gatard,Albert Nguyen Van Nhien,Matthieu Courty,Sandrine Bouquillon
Molecules , 2013, DOI: 10.3390/molecules180911512
Abstract: D-Xylose-based ionic liquids have been prepared from D-xylose following a five steps reaction sequence, the key step being a click cycloaddition. These ionic liquids (ILs) have been characterized through classical analytical methods (IR, NMR, mass spectroscopy, elemental analysis) and their stability constants, Tg and Tdec, were also determined. Considering their properties and their hydrophilicity, these compounds could be alternative solvents for chemical applications under mild conditions.
Vitamin A deficiency during pregnancy of HIV infected and non-infected women in tropical settings of Northwest Ethiopia
Andargachew Mulu, Afework Kassu, Kahsay Huruy, Birhanemeskel Tegene, Gashaw Yitayaw, Masayo Nakamori, Nguyen Van Nhien, Assegedech Bekele, Yared Wondimhun, Shigeru Yamamoto, Fusao Ota
BMC Public Health , 2011, DOI: 10.1186/1471-2458-11-569
Abstract: In this cross-sectional study, blood samples were collected from 423 pregnant women and from 55 healthy volunteers who visited the University of Gondar Hospital. Serum concentration of vitamin A was measured by high performance liquid chromatography.After controlling for total serum protein, albumin and demographic variables, the mean ± SD serum vitamin A in HIV seropositive pregnant women (0.96 ± 0.42 μmol/L) was significantly lower than that in pregnant women without HIV infection (1.10 ± 0.45 μmol/L, P < 0.05). Likewise, the level of serum vitamin A in HIV seropositive non-pregnant women (0.74 ± 0.39) was significantly lower than that in HIV negative non-pregnant women (1.18 ± 0.59 μmol/L, P < 0.004). VAD (serum retinol < 0.7 μmol/L) was observed in 18.4% and 17.7% of HIV infected and uninfected pregnant women, respectively. Forty six percent of non-pregnant women with HIV infection had VAD while only 28% controls were deficient for vitamin A (P = 0.002).The present study shows that VAD is a major public health problem among pregnant women in the tropical settings of Northwest Ethiopia. Considering the possible implications of VAD during pregnancy, we recommend multivitamin (which has a lower level of vitamin A) supplementation in the care and management of pregnant women with or without HIV infection.Vitamin A deficiency (VAD) is known to be a significant public health problem around the world and it is particularly serious among women of reproductive age in South-East Asia and Africa [1-4]. It has now become evident that VAD in women has negative consequences on their health status as well as on their infants [3,4]. The link between VAD morbidity and mortality from infectious diseases [5] and non-infectious diseases [6-8] has been known for several years.VAD in pregnant women is associated with night blindness, severe anaemia, wasting, malnutrition, and reproductive and infectious morbidity [9], and increased risk of mortality 1-2 years following delivery [4].
Early Pandemic Influenza (2009 H1N1) in Ho Chi Minh City, Vietnam: A Clinical Virological and Epidemiological Analysis
Tran Tinh Hien equal contributor,Maciej F. Boni equal contributor ,Juliet E. Bryant equal contributor,Tran Thuy Ngan equal contributor,Marcel Wolbers,Tran Dang Nguyen,Nguyen Thanh Truong,Nguyen Thi Dung,Do Quang Ha,Vo Minh Hien,Tran Tan Thanh,Le Nguyen Truc Nhu,Le Thi Tam Uyen,Pham Thi Nhien,Nguyen Tran Chinh,Nguyen Van Vinh Chau,Jeremy Farrar,H. Rogier van Doorn equal contributor
PLOS Medicine , 2010, DOI: 10.1371/journal.pmed.1000277
Abstract: Background To date, little is known about the initial spread and response to the 2009 pandemic of novel influenza A (“2009 H1N1”) in tropical countries. Here, we analyse the early progression of the epidemic from 26 May 2009 until the establishment of community transmission in the second half of July 2009 in Ho Chi Minh City (HCMC), Vietnam. In addition, we present detailed systematic viral clearance data on 292 isolated and treated patients and the first three cases of selection of resistant virus during treatment in Vietnam. Methods and Findings Data sources included all available health reports from the Ministry of Health and relevant health authorities as well as clinical and laboratory data from the first confirmed cases isolated at the Hospital for Tropical Diseases in HCMC. Extensive reverse transcription (RT)-PCR diagnostics on serial samples, viral culture, neuraminidase-inhibition testing, and sequencing were performed on a subset of 2009 H1N1 confirmed cases. Virological (PCR status, shedding) and epidemiological (incidence, isolation, discharge) data were combined to reconstruct the initial outbreak and the establishment of community transmission. From 27 April to 24 July 2009, approximately 760,000 passengers who entered HCMC on international flights were screened at the airport by a body temperature scan and symptom questionnaire. Approximately 0.15% of incoming passengers were intercepted, 200 of whom tested positive for 2009 H1N1 by RT-PCR. An additional 121 out of 169 nontravelers tested positive after self-reporting or contact tracing. These 321 patients spent 79% of their PCR-positive days in isolation; 60% of PCR-positive days were spent treated and in isolation. Influenza-like illness was noted in 61% of patients and no patients experienced pneumonia or severe outcomes. Viral clearance times were similar among patient groups with differing time intervals from illness onset to treatment, with estimated median clearance times between 2.6 and 2.8 d post-treatment for illness-to-treatment intervals of 1–4 d, and 2.0 d (95% confidence interval 1.5–2.5) when treatment was started on the first day of illness. Conclusions The patients described here represent a cross-section of infected individuals that were identified by temperature screening and symptom questionnaires at the airport, as well as mildly symptomatic to moderately ill patients who self-reported to hospitals. Data are observational and, although they are suggestive, it is not possible to be certain whether the containment efforts delayed community transmission in Vietnam.
Spread of Phytophthora capsici in Black Pepper (Piper nigrum) in Vietnam  [PDF]
Van Long Nguyen
Engineering (ENG) , 2015, DOI: 10.4236/eng.2015.78047
Abstract: Black pepper is the one of most important export products in Vietnam. As the largest exporter, Vietnam’s pepper commodities account for 58% of total worldwide exporters. However, Vietnam’s pepper production is dealing with disease problems, especially foot rot/quick death infected by Phytophthora capsici. The disease results in serious and rapid spread and infection in Vietnam, with yearly reduction of about 2% of total pepper area. Disease management is recently challenging scientists and producers. Investigating characteristics of Phytophthora capsici and causes, therefore, play a significant role in treatment. This paper has indicated three main causes, which contribute to serious infection and outbreak of Phytophthora capsici; they are biological characteristics, climatic condition and cultivation. To control this disease, early detection and prevention are the best ways to manage disease. Finding new varieties, which are Phytophthora capsici tolerance or resistance, is significant in black pepper production worldwide.
Institutional Quality and the Public Investment-Growth Relationship in Vietnam  [PDF]
Nguyen Van Bon
Theoretical Economics Letters (TEL) , 2019, DOI: 10.4236/tel.2019.94046
Abstract: Questions concerning the relationship between public capital spending and economic growth under different institutional environments are of great analytical and empirical interest. This paper investigates the role of institutional quality in the public investment-growth relationship for a balanced panel data of 52 provinces in Vietnam during the period 2005-2014 through the estimation method of difference panel GMM Arellano-Bond. The results show twofold. First, public investment and institutional quality significantly promote economic growth, but their interaction term impedes it. Second, the public investment-growth relationship is positive under good institutional environment and negative under poor one. These findings suggest some important policy implications related to public capital spending in developing countries.
In vivo susceptibility of Plasmodium falciparum to artesunate in Binh Phuoc Province, Vietnam
Hien Tran,Thuy-Nhien Nguyen,Phu Nguyen,Boni Maciej F
Malaria Journal , 2012, DOI: 10.1186/1475-2875-11-355
Abstract: Background By 2009, there were worrying signs from western Cambodia that parasitological responses to artesunate-containing treatment regimens for uncomplicated Plasmodium falciparum malaria were slower than elsewhere which suggested the emergence of artemisinin resistance. Vietnam shares a long land border with Cambodia with a large number of migrants crossing it on a daily basis. Therefore, there is an urgent need to investigate whether there is any evidence of a change in the parasitological response to the artemisinin derivatives in Vietnam. Methods From August 2010 to May 2011, a randomized controlled clinical trial in uncomplicated falciparum malaria was conducted to compare two doses of artesunate (AS) (2mg/kg/day versus 4 mg/kg/day for three days) followed by dihydroartemisinin-piperaquine (DHA-PPQ) and a control arm of DHA-PPQ. The goal was characterization of the current efficacy of artesunate in southern Vietnam. The primary endpoint of this study was the parasite clearance half-life; secondary endpoints included the parasite reduction ratios at 24 and 48 hours and the parasite clearance time. Results 166 patients were recruited into the study. The median parasite clearance half-lives were 3.54 (AS 2mg/kg), 2.72 (AS 4mg/kg), and 2.98 hours (DHA-PPQ) (p=0.19). The median parasite-reduction ratio at 24 hours was 48 in the AS 2mg/kg group compared with 212 and 113 in the other two groups, respectively (p=0.02). The proportions of patients with a parasite clearance time of >72 hours for AS 2mg/kg, AS 4mg/kg and DHA-PPQ were 27%, 27%, and 22%, respectively. Early treatment failure occurred in two (4%) and late clinical failure occurred in one (2%) of the 55 patients in the AS 2mg/kg group, as compared with none in the other two study arms. The PCR-corrected adequate clinical and parasitological response (APCR) rates in the three groups were 94%, 100%, and 100% (p=0.04). Conclusions This study demonstrated faster P. falciparum parasite clearance in southern Vietnam than in western Cambodia but slower clearance in comparison with historical data from Vietnam. Further studies to determine whether this represents the emergence of artemisinin resistance in this area are needed. Currently, the therapeutic response to DHA-PPQ remains satisfactory in southern Vietnam. Trial registration NTC01165372
A Study of the Optical Properties in ZnWO4 Nanorods Synthesized by Hydrothermal Method  [PDF]
Nguyen Van Minh, Nguyen Manh Hung
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.28133
Abstract: We investigate the effect of synthesized time on the structure, as well as optical properties in ZnWO4 nano rod prepared by hydrothermal method. The prepared rods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman scattering, absorption and photoluminescent (PL) spectra techniques. The size and morphology of ZnWO4 nano-rod can be controlled by adjusting the reaction time. The resultant sample is a pure phase of ZnWO4 without any impurities. The results showed that the optical property of ZnWO4 nanoparticles obviously relied on their rod sizes.
The Psychological Well-Being among Left-Behind Children of Labor Migrant Parents in Rural Northern Vietnam  [PDF]
Nguyen Van Luot, Nguyen Ba Dat
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.56017
Abstract: Background: In Asia, especially in China and ASEAN, it has been an obvious trend that the population in general and parents in particular leave the countryside to bigger cities or more developed countries for employment opportunities. Many migrant workers are forced to leave their children at home with caregivers, particularly in families with both husband and wife working away from home. Studies worldwide have showed that, besides positive economic and social impacts, labor migrant parents also cause negative effects to the well-being of those they leave behind, especially children. However, this study orientation has not generated significant interest in Vietnam. Participants: This paper indicates the results of a survey on 469 left-behind children of labor migrant parents in rural areas by comparing them with a control group of 650 children living with their parents in three rural areas of North Vietnam including Phu Tho, Bac Ninh and Ha Nam provinces. Besides, we also survey 363 caregivers (parent or grandfather/grandmother of left-behind children) about psychological well-being of left-behind children. Method: Strengths and Difficulties Questionnaire (SDQ) was used for this study. SDQ was Vietnamized by author Dang Hoang Minh et al. (2013) and adaptable to Vietnamese teenagers. Results: As reported by the surveyed children, the SDQ mean total difficulties score of those having migrant parents was 12.55 (SD = 5.96) and 18.9% of these children had scores higher than the cut-off score. As rated by caregivers, they were 11.12 (SD = 5.14) and 15.1%, respectively. There is a statistically significant difference in mental health between the LBC and non-LBC group. The general trend is that the LBC reported to have higher scores of total difficulties and specific expressions
Contact with Biological Parents for Children in Residental Care: A Vietnam Study  [PDF]
Nguyen Ba Dat, Nguyen Van Luot, Nguyen Ha Thanh
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.611021
Abstract: Children living in residential care have a degree of separation from their parents and other family members. Based on attachment theory, this study was conducted to analyze the contact between these children and their biological parents, and the factors affecting this contact. The sample included 382 children (orphans, abandoned or helpless children, children whose parents are deprived of custody or are unable to raise a child) living in residential centers located in North, Central and South of Vietnam. Data were obtained by semi-structured interviews. The results showed that, on average, children contact their parents and family members once a month. In addition, variables such as family image in children’s mind and joyfulness when meeting parents are the best predictors of contact between children and parents, family members. The contact between children and parents is arguably considered as a form of consolidation and maintenance of emotional relationship.
Mean Threshold and ARNN Algorithms for Identification of Eye Commands in an EEG-Controlled Wheelchair  [PDF]
Nguyen Thanh Hai, Nguyen Van Trung, Vo Van Toi
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.510B059
Abstract:

This paper represented Autoregressive Neural Network (ARNN) and meant threshold methods for recognizing eye movements for control of an electrical wheelchair using EEG technology. The eye movements such as eyes open, eyes blinks, glancing left and glancing right related to a few areas of human brain were investigated. A Hamming low pass filter was applied to remove noise and artifacts of the eye signals and to extract the frequency range of the measured signals. An autoregressive model was employed to produce coefficients containing features of the EEG eye signals. The coefficients obtained were inserted the input layer of a neural network model to classify the eye activities. In addition, a mean threshold algorithm was employed for classifying eye movements. Two methods were compared to find the better one for applying in the wheelchair control to follow users to reach the desired direction. Experimental results of controlling the wheelchair in the indoor environment illustrated the effectiveness of the proposed approaches.

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