In this work, AgNPs/PVA/Cellulose was used as a substrate material for surface Raman scattering enhancement. Silver nanoparticles (AgNPs) was synthesized by Lee and Meisel's method with the average ...particles size of 15.4 nm. Then, this silver colloid was made a homogenous coating on polyvinyl alcohol and cellulose film and structural characteristics of this material were determined using Scanning Electron Microscopy (SEM). The findings demonstrated that the Raman shifts of the pesticide will be identified by the SERS method at 1660 cm−1, 2234 cm−1 (strong intensity), and at 3077 cm−1, 1033 cm−1, 1457 cm−1 (medium intensity) when using the excited laser with wavelength of 532 nm. Under excited laser, the limit of chlorfenapyr detection is 1 ppm (mg l−1), allowing determination of chlorfenapyr residue in food. Potential applications identified food samples containing chlorfenapyr residue for rapid detection, low cost, non-destructive nature and minimal sample preparation.
In this work, a complete picture of the relationship between the structural and optical properties of Al-doped CaMoO4:Eu phosphor was investigated empirically and theoretically. A series of Al-doped ...CaMoO4:Eu phosphors were synthesized by solid-state reaction. X-ray diffraction analysis and Rietveld refinement confirmed the formation of a single-phase tetragonal CaMoO4. Under the excitation wavelength of 395 nm, the phosphors exhibited typical red emission bands of Eu3+ as a function of Al3+ doping contents and reached a maximum value at 0.1 mol % Al3+. In addition, the CaMoO4:0.05Eu, 0.1Al phosphor showed chromaticity coordinates (0.6406, 0.3370), which is close to the pure red color as standardized by the National Television System Committee. Significantly, the red emission intensity of Al-doped CaMoO4: 0.05Eu phosphor was 5-times higher than that of the undoped one. This enhancement was explained by Judd-Ofelt (JO) analysis, from which intensity parameters (Ωλ, λ = 2, 4) and radiative properties including branching ratios (βr), transition probability (A), radiative lifetime (τcal), and stimulated emission cross-section (σe) of the phosphor were derived. Judd-Ofelt analysis confirmed that Al3+ promotes the covalent character in the Eu–O bond and the asymmetry in the CaMoO4 crystalline structure. The CaMoO4: 0.05Eu, 0.1Al phosphor generates strong red emission and possesses high values of branching ratio (81.80%), emission cross-section (102.3×10−22 cm2) and quantum efficiency (48.44%) and is potential for low-cost WLED applications.
•Eu3+, Al3+ co-doped CaMoO4 phosphor was synthesized by solid-state reaction method.•Co-doping of Eu3+ and Al3+ induces the preferential formation of crystalline tetragonal CaMoO4.•Luminescence of Eu3+, Al3+ co-doped CaMoO4 phosphor was increased significantly compared to that of Al3+-free phosphor.•Enhanced red emission mechanism of CaMoO4: Eu3+, Al3+ phosphor was explained in detail.
Introduction: Pediatric DLBCL is considered a homogenous group and has superior outcomes compared to adults. This study investigated the clinical pathology and immunohistochemical distinction between ...adult and pediatric large B-cell lymphoma. Methods: A cross-sectional study of 314 NHLs with the morphology of diffuse pattern, large B-cell, and CD20 expression was investigated. Results: Of 314 cases, there were 6 cases of pleomorphic MCL (all in adults), 19 cases of Burkitt lymphoma (all in children), and 289 cases of DLBCL. Pediatric DLBCL had many striking differences: More frequency in extra-nodal sites; a higher proportion of centroblastic morphology; a predominance of GCB-type; a high proliferation rate; an infrequency of Bcl2 protein expression, and a lack of double-expresser lymphoma. Conclusions: Our study demonstrated the significant biological differences between adult and pediatric DLBCL.
Abstract
In this study, the semi‐aromatic polyamide membranes were synthesized by the interfacial polymerization between piperazine (PIP) monomers in the water phase and Benzene‐1,3,5‐tricarbonyl ...chloride in the organic phase. To further modify the semi‐aromatic pervaporation membrane, the two amino acids, glycine, and
l
‐lysine, were mixed with PIP monomers for interfacial polymerization. The morphology and physicochemical properties of the synthesized membranes were analyzed using Fourier transform infrared (FTIR), field emission scanning electron microscope (FE‐SEM), atomic force microscope (AFM), and contact angle measurements. The results show that the semi‐aromatic polyamide membranes modified by the two amino acids possess a higher hydrophilic surface and lower thickness compared to the unmodified membrane. Additionally, the permeation flux of the semi‐aromatic polyamide membranes was improved by 18.6% and 38.5% as modified with glycine and
l
‐lysine, respectively, at the operating temperature of 70°C when the rejection of both NaCl and arsenic are higher than 99.8%. Furthermore, the operating temperature significantly influenced the permeation flux, while the salt rejections were insignificantly affected. The permeation flux increases by 3.2‐ and 4.0‐folds for glycine and lysine‐modified membranes, respectively, when elevating the feed temperature from 40°C to 70°C. The highest permeation flux of 29.5 kg m
−2
h
−1
with a 5 wt% NaCl rejection of 99.8% was obtained at 70°C by using 0.3 wt%
l
‐lysine modified polyamide (PA) membrane. For elimination of 1.5 mg L
−1
As solution at the feed temperature of 70°C, such
l
‐lysine modified PA membrane exhibited the permeation flux of 30.5 kg m
−2
h
−1
and As rejection of 99.6%, respectively. This work provides a cost‐saving, facile, and eco‐friendly preparation method for effectively improving the permeation flux while not sacrificing the high rejection of salts of the modified membranes.
Background
Drug resistance has become a major concern for antiviral therapy in patients with chronic hepatitis B (CHB), leading to an increased risk of treatment failure. We aimed to identify the ...prevalence of hepatitis B virus (HBV) DNA polymerase mutations and to determine the frequency of HBV genotypes and subgenotypes in treatment-naive patients with CHB in Mekong Delta, Vietnam.
Methods
Of the 550 drug-naive CHB patients from Mekong Delta, their serum samples were analyzed for HBV DNA mutations, genotypes, and subgenotypes using polymerase chain reaction sequencing.
Results
Of the 550 patients who were infected with either HBV genotype B (72.9%) or genotype C (27.1%), the frequencies of subgenotypes were 19% B1, 3.6% B2, 10.3% B3, 39.8% B4, 0.4% C1, and 26.9% C2. The only mutation that was detected in 54 patients (10.7%) was rtV207M. The rtV207M mutation was found among 13.9% (51/368) of genotype B and among 2.2% (3/137) of genotype C (
P
< 0.0001).
Discussion
Genotype B and subgenotype B4 are predominant in Mekong Delta. Only 1 mutation rtV207M is discovered in our study. These findings suggest that it is unnecessary to test for HBV resistance mutation before delivering antiviral therapy.
The importation of SARS-CoV-2 through air travel poses substantial risks to generate new COVID-19 outbreaks. Timely contact tracing is particularly crucial to limit onwards transmission in settings ...without established community transmission.
We conducted an in-depth analysis of the response to a big flight-associated COVID-19 outbreak in Vietnam in March 2020 that involved contact tracing, systematic testing and strict quarantine up to third generation contacts.
183 primary contacts from the flight as well as 1000 secondary and 311 third generation contacts were traced, tested, and quarantined across 15 provinces across Vietnam. The protracted confirmation of the index case at 3 days and 19 h after arrival resulted in isolation/quarantine delays of 6.8 days (IQR 6.3–6.8) and 5.8 days (IQR 5.8–7.0) for primary and secondary cases, respectively, which generated 84.0 and 26.4 person-days of community exposure from primary and secondary cases, respectively. Nevertheless, only 5 secondary cases occurred.
A large flight-related COVID-19 cluster was successfully contained through timely, systematic and comprehensive public health responses despite delayed index case identification. Multiagency collaboration and pre-established mechanisms are crucial for low and middle income countries like Vietnam to limit community transmission after COVID-19 importation through air travel.
•Successful control of large flight-imported COVID-19 outbreaks is possible.•Delayed index case confirmation complicates response measures.•A combination of contact tracing, systematic testing and quarantine is key.•Mandatory testing at arrival might be justified for certain settings.•A whole-of-government approach and pre-established protocols are important.
Drug resistant tuberculosis (TB) is increasing in prevalence worldwide. Treatment failure and relapse is known to be high for patients with isoniazid resistant TB treated with standard first line ...regimens. However, risk factors for unfavourable outcomes and the optimal treatment regimen for isoniazid resistant TB are unknown. This cohort study was conducted when Vietnam used the eight month first line treatment regimen and examined risk factors for failure/relapse among patients with isoniazid resistant TB.
Between December 2008 and June 2011 2090 consecutive HIV-negative adults (≥18 years of age) with new smear positive pulmonary TB presenting at participating district TB units in Ho Chi Minh City were recruited. Participants with isoniazid resistant TB identified by Microscopic Observation Drug Susceptibility (MODS) had extended follow-up for 2 years with mycobacterial culture to test for relapse. MGIT drug susceptibility testing confirmed 239 participants with isoniazid resistant, rifampicin susceptible TB. Bacterial and demographic factors were analysed for association with treatment failure and relapse.
Using only routine programmatic sputum smear microscopy for assessment, (months 2, 5 and 8) 30/239 (12.6%) had an unfavourable outcome by WHO criteria. Thirty-nine patients were additionally detected with unfavourable outcomes during 2 year follow up, giving a total of 69/239 (28.9%) of isoniazid (INH) resistant cases with unfavourable outcome by 2 years of follow-up. Beijing lineage was the only factor significantly associated with unfavourable outcome among INH-resistant TB cases during 2 years of follow-up. (adjusted OR = 3.16 1.54-6.47, P = 0.002).
One third of isoniazid resistant TB cases suffered failure/relapse within 2 years under the old eight month regimen. Over half of these cases were not identified by standard WHO recommended treatment monitoring. Intensified research on early identification and optimal regimens for isoniazid resistant TB is needed. Infection with Beijing genotype of TB is a significant risk factor for bacterial persistence on treatment resulting in failure/relapse within 2 years. The underlying mechanism of increased tolerance for standard drug regimens in Beijing genotype strains remains unknown.
This paper reports the way for the synthesis of nanoplate VO
(B) particles with controlled morphology. Nanoplate VO
(B) particle was synthesized by hydrothermal method. Microstructure of VO
(B) ...particles were controlled by hydrothermal temperatures and use of Zn doping into VO
(B) matrix. The microstructure of the particles was shifted from nanowires to nanoplate morphology by changing of hydrothermal temperatures. The doping of Zn into VO
nanoparticles resulted in an effective achievement of VO
(B) phase. In addition, luminescence of VO
(B) nanoparticle was also controlled by the use Zn doping. These results suggest that the potential application of Zn doped VO
(B) particles for potential application in optical and energy techniques.
Abstract
Background
During the first half of 2014, a severe outbreak of measles occurred in northern Vietnam, causing 15 033 confirmed cases and 146 deaths.
Methods
To evaluate the population-level ...seroprevalence of protection against measles in the period before the outbreak, we made use of an existing age-stratified serum bank, collected over the year before the outbreak, between November 2012 and December 2013, from 4 sites across the country (Hanoi, Hue, Dak Lak, and Ho Chi Minh City). Data from the UNICEF’s Multiple Indicator Clustered Surveys (MICS), carried out in Vietnam during the first quarter of 2014, were used to assess the vaccine coverage in 6 ecological regions of Vietnam.
Results
Results revealed a large discrepancy between levels of protection, as estimated from the serology and vaccine coverage estimated by UNICEF’s MICS. Variation in seroprevalence across locations and age groups corresponded with reported numbers of measles cases, most of which were among the 0–2-year-old age group and in the northern part of the country.
Conclusions
Our study presents a strong case in favor of a serosurveillance sentinel network that could be used to proactively tune vaccination policies and other public health interventions.
Highlights • Rhino, Influenza and Corona viruses caused ∼50% of ILI in Vietnam households. • There was no clear seasonality for ILI, or for individual viruses causing ILI. • Children did not ...contribute substantially to ILI burden or transmission. • Seasonality and the contribution of children were unlike temporal settings. • Seasonality and social factors may affect the involvement of children in ILI.
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