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Search Results: 1 - 10 of 48742 matches for " Le Van Tinh "
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Investigation the Dimensional Ratio Effect on the Resonant Properties of Piezoelectric Ceramic Disk  [PDF]
Vo Thanh Tung, Nguyen Trong Tinh, Truong Van Chuong, Nguyen Thi Mai H??ng, Dang Anh Tuan, Le Van Truyen
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.412202

In this work, the vibration characteristics of a piezoelectric ceramic disk with different dimensional ratio are studied by simulation method. Computational finite element modeling combined with the computational programs has allowed for the prediction of the effect, the change of diameter-to-thickness ratio on the resonant characteristics, the vibration modes as well as comparing the physic properties of piezoceramics. Three types of piezoelectric materials were chosen, piezoelectric materials (PZT) and Pb-free piezoelectric materials Ba(Zr0.2Ti0.8)O3-50(Ba0.7Ca0.3)TiO3(BZT-50BCT), BaTiO3 for research.

The Effect of Polyvinylpyrrolidone on the Optical Properties of the Ni-Doped ZnS Nanocrystalline Thin Films Synthesized by Chemical Method
Tran Minh Thi,Le Van Tinh,Bui Hong Van,Pham Van Ben,Vu Quoc Trung
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/528047
Abstract: We report the optical properties of polyvinyl-pyrrolidone (PVP) and the influence of PVP concentration on the photoluminescence spectra of the PVP (PL) coated ZnS : Ni nanocrystalline thin films synthesized by the wet chemical method and spin-coating. PL spectra of samples were clearly showed that the 520 nm luminescence peak position of samples remains unchanged, but their peak intensity changes with PVP concentration. The PVP polymer is emissive with peak maximum at 394 nm with the exciting wavelength of 325 nm. The photoluminescence exciting (PLE) spectrum of PVP recorded at 394 nm emission shows peak maximum at 332 nm. This excitation band is attributed to the electronic transitions in PVP molecular orbitals. The absorption edges of the PVP-coated ZnS : Ni0.3% samples that were shifted towards shorter wavelength with increasing of PVP concentration can be explained by the absorption of PVP in range of 350 nm to 400 nm. While the PVP coating does not affect the microstructure of ZnS : Ni nanomaterial, the analyzed results of the PL, PLE, and time-resolved PL spectra and luminescence decay curves of the PVP and PVP-coated ZnS : Ni samples allow to explain the energy transition process from surface PVP molecules to the Ni2
Epidemiology of forest malaria in central Vietnam: a large scale cross-sectional survey
Annette Erhart, Ngo Thang, Phan Van Ky, Ta Tinh, Chantal Van Overmeir, Niko Speybroeck, Valerie Obsomer, Le Hung, Le Thuan, Marc Coosemans, Umberto D'alessandro
Malaria Journal , 2005, DOI: 10.1186/1475-2875-4-58
Abstract: A large-scale malaria morbidity survey to measure malaria endemicity and identify important risk factors was carried out in 43 villages situated in a forested area of Ninh Thuan province, south central Vietnam. Four thousand three hundred and six randomly selected individuals, aged 10–60 years, participated in the survey. Rag Lays (86%), traditionally living in the forest and practising "slash and burn" cultivation represented the most common ethnic group. The overall parasite rate was 13.3% (range [0–42.3] while Plasmodium falciparum seroprevalence was 25.5% (range [2.1–75.6]). Mapping of these two variables showed a patchy distribution, suggesting that risk factors other than remoteness and forest proximity modulated the human-vector interactions. This was confirmed by the results of the multivariate-adjusted analysis, showing that forest work was a significant risk factor for malaria infection, further increased by staying in the forest overnight (OR= 2.86; 95%CI [1.62; 5.07]). Rag Lays had a higher risk of malaria infection, which inversely related to education level and socio-economic status. Women were less at risk than men (OR = 0.71; 95%CI [0.59; 0.86]), a possible consequence of different behaviour. This study confirms that malaria endemicity is still relatively high in this area and that the dynamics of transmission is constantly modulated by the behaviour of both humans and vectors. A well-targeted intervention reducing the "vector/forest worker" interaction, based on long-lasting insecticidal material, could be appropriate in this environment.Controlling malaria in forested areas remains a challenge in many parts of Asia and South America [1-7]. In Vietnam, forest malaria occurs in 16 provinces (out of 64) situated in the central part of the country (11 in the Central area, 4 in the western highlands and 1 in the south-eastern region). According to the figures reported by the National Malaria Control Program (NMCP), about half of the total malaria cases,
About increase of durability of ship shafts with cracks
Doan Van Tinh
Vestnik of Astrakhan State Technical University. Series: Marine Engineering and Technologies , 2009,
Abstract: The technique to calculate durability of ship shafts with cracks on share modes is considered in the paper. The items of information such as growth rate of cracks, and the way to define stress intensity factor for steel "35" are de-scribed on the basis of experimental tests of samples. The calculation results of durability of the propeller shaft with cracks of a tanker of five thousand tons displacement of the Vietnamese construction on share modes are shown.
Clinical Features of Dengue in a Large Vietnamese Cohort: Intrinsically Lower Platelet Counts and Greater Risk for Bleeding in Adults than Children
Trung Dinh The ,Thao Le Thi Thu,Dung Nguyen Minh,Ngoc Tran Van,Hien Tran Tinh,Chau Nguyen Van Vinh,Marcel Wolbers,Tam Dong Thi Hoai,Jeremy Farrar,Cameron Simmons,Bridget Wills
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001679
Abstract: Background As dengue spreads to new geographical regions and the force of infection changes in existing endemic areas, a greater breadth of clinical presentations is being recognised. Clinical experience suggests that adults manifest a pattern of complications different from those observed in children, but few reports have described the age-related spectrum of disease in contemporaneous groups of patients recruited at the same geographical location. Methodology/Principal Findings Using detailed prospectively collected information from ongoing studies that encompass the full spectrum of hospitalised dengue cases admitted to a single hospital in southern Vietnam, we compared clinical and laboratory features, management, and outcome for 647 adults and 881 children with confirmed dengue. Signs of vascular leakage and shock were more frequent and more severe in children than adults, while bleeding manifestations and organ involvement were more common in adults. Additionally, adults experienced significantly more severe thrombocytopenia. Secondary infection but not serotype was independently associated with greater thrombocytopenia, although with a smaller effect than age-group. The effect of age-group on platelet count was also apparent in the values obtained several weeks after recovery, indicating that healthy adults have intrinsically lower counts compared to children. Conclusions/Significance There are clear distinctions between adults and children in the pattern of complications seen in association with dengue infection, and these depend partly on intrinsic age-dependent physiological differences. Knowledge of such differences is important to inform research on disease pathogenesis, as well as to encourage development of management guidelines that are appropriate to the age-groups at risk.
An Outbreak of Severe Infections with Community-Acquired MRSA Carrying the Panton-Valentine Leukocidin Following Vaccination
Tang Chi Thuong, Nguyen Dac Tho, Ngo Thi Hoa, Nguyen Thi Minh Phuong, Le Van Tuan, To Song Diep, Jodi Lindsay, Nguyen The Dung, Bach Van Cam, Le Quoc?Thinh, Le Thanh Hai, Le Dieu Linh, James Campbell, Nguyen Thi Kim Tien, Nguyen Van Vinh Chau, Joshua Cockfield, Le Truong Giang, Phan Van Nghiem, Le Hoang Son, Huynh Tan Son, Le Van Phung, Megan Counahan, Adwoa Bentsi-Enchill, Richard Brown, James Simmerman, Nguyen Tran Chinh, Tran Tinh Hien, Jeremy Farrar, Constance Schultsz
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000822
Abstract: Background Infections with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination. Methods and Findings We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mec type V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, although they belong to the same lineage. Conclusions We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings.
Viral Aetiology of Central Nervous System Infections in Adults Admitted to a Tertiary Referral Hospital in Southern Vietnam over 12 Years
Le Van Tan ,Le Hong Thai,Nguyen Hoan Phu,Ho Dang Trung Nghia,Ly Van Chuong,Dinh Xuan Sinh,Nguyen Duy Phong,Nguyen Thi Hoang Mai,Dinh Nguyen Huy Man,Vo Minh Hien,Nguyen Thanh Vinh,Jeremy Day,Nguyen Van Vinh Chau,Tran Tinh Hien,Jeremy Farrar,Menno D. de Jong,Guy Thwaites,H. Rogier van Doorn,Tran Thi Hong Chau
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003127
Abstract: Background Central nervous system (CNS) infections are important diseases in both children and adults worldwide. The spectrum of infections is broad, encompassing bacterial/aseptic meningitis and encephalitis. Viruses are regarded as the most common causes of encephalitis and aseptic meningitis. Better understanding of the viral causes of the diseases is of public health importance, in order to better inform immunization policy, and may influence clinical management. Methodology/Principal Findings Study was conducted at the Hospital for Tropical Diseases in Ho Chi Minh City, a primary, secondary, and tertiary referral hospital for all southern provinces of Vietnam. Between December 1996 and May 2008, patients with CNS infections of presumed viral origin were enrolled. Laboratory diagnostics consisted of molecular and serological tests targeted at 14 meningitis/encephalitis-associated viruses. Of 291 enrolled patients, fatal outcome and neurological sequelae were recorded in 10% (28/291) and 27% (78/291), respectively. Mortality was especially high (9/19, 47%) amongst those with confirmed herpes simplex encephalitis which is attributed to the limited availability of intravenous acyclovir/valacyclovir. Japanese encephalitis virus, dengue virus, herpes simplex virus, and enteroviruses were the most common viruses detected, responsible for 36 (12%), 19 (6.5%), 19 (6.5%) and 8 (2.7%) respectively, followed by rubella virus (6, 2%), varicella zoster virus (5, 1.7%), mumps virus (2, 0.7%), cytomegalovirus (1, 0.3%), and rabies virus (1, 0.3%). Conclusions/Significance Viral infections of the CNS in adults in Vietnam are associated with high morbidity and mortality. Despite extensive laboratory testing, 68% of the patients remain undiagnosed. Together with our previous reports, the data confirm that Japanese encephalitis virus, dengue virus, herpes simplex virus, and enteroviruses are the leading identified causes of CNS viral infections in Vietnam, suggest that the majority of morbidity/mortality amongst patients with a confirmed/probable diagnosis is preventable by adequate vaccination/treatment, and are therefore of public health significance.
Estimation of dependence of durability of ship shaft with cracks on their initial sizes
Doan Van Tinh,Mamontov Victor Andreevich
Vestnik of Astrakhan State Technical University. Series: Marine Engineering and Technologies , 2009,
Abstract: The technique of calculation of durability of ship shaft with cracks is con-sidered depending on the initial sizes of cracks. The information on the develop-ment of cracks is given and the way of definition of the factor of pressure intensity for experimental samples made of 35 steel is described. The diagram of the endurance failure is drawn on the basis of the results of the experimental researches. The basic constants of the material n and c are determined. The results of calculation of durability of the propeller shaft with cracks of the tanker with 1 000 T deadweight of the Vietnamese construction are given depending on the initial sizes of cracks.
Viral Etiology of Encephalitis in Children in Southern Vietnam: Results of a One-Year Prospective Descriptive Study
Le Van Tan ,Phan Tu Qui,Do Quang Ha,Nguyen Bach Hue,Lam Quoi Bao,Bach Van Cam,Truong Huu Khanh,Tran Tinh Hien,Nguyen Van Vinh Chau,Tran Tan Tram,Vo Minh Hien,Tran Vu Thieu Nga,Constance Schultsz,Jeremy Farrar,H. Rogier van Doorn,Menno D. de Jong
PLOS Neglected Tropical Diseases , 2010, DOI: 10.1371/journal.pntd.0000854
Abstract: Background Acute encephalitis is an important and severe disease in children in Vietnam. However, little is known about the etiology while such knowledge is essential for optimal prevention and treatment. To identify viral causes of encephalitis, in 2004 we conducted a one-year descriptive study at Children's Hospital Number One, a referral hospital for children in southern Vietnam including Ho Chi Minh City. Methodology/Principal Findings Children less than 16 years of age presenting with acute encephalitis of presumed viral etiology were enrolled. Diagnostic efforts included viral culture, serology and real time (RT)-PCRs. A confirmed or probable viral causative agent was established in 41% of 194 enrolled patients. The most commonly diagnosed causative agent was Japanese encephalitis virus (n = 50, 26%), followed by enteroviruses (n = 18, 9.3%), dengue virus (n = 9, 4.6%), herpes simplex virus (n = 1), cytomegalovirus (n = 1) and influenza A virus (n = 1). Fifty-seven (29%) children died acutely. Fatal outcome was independently associated with patient age and Glasgow Coma Scale (GCS) on admission. Conclusions/Significance Acute encephalitis in children in southern Vietnam is associated with high mortality. Although the etiology remains unknown in a majority of the patients, the result from the present study may be useful for future design of treatment and prevention strategies of the disease. The recognition of GCS and age as predictive factors may be helpful for clinicians in managing the patient.
Viral Etiologies of Acute Respiratory Infections among Hospitalized Vietnamese Children in Ho Chi Minh City, 2004–2008
Anh Ha Lien Do,H. Rogier van Doorn,My Ngoc Nghiem,Juliet E. Bryant,Thanh Hang thi Hoang,Quang Ha Do,Tan Le Van,Tan Thanh Tran,Bridget Wills,Vinh Chau van Nguyen,Minh Hien Vo,Cong Khanh Vo,Minh Dung Nguyen,Jeremy Farrar,Tinh Hien Tran,Menno D. de Jong
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018176
Abstract: The dominant viral etiologies responsible for acute respiratory infections (ARIs) are poorly understood, particularly among hospitalized children in resource-limited tropical countries where morbidity and mortality caused by ARIs are highest. Improved etiological insight is needed to improve clinical management and prevention.
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