Single-phase far-red-emitting ZnAl2O4:Cr3+ phosphor has been successfully synthesized by a sol-gel method. The phosphor can be well excited by NUV, violet, and green lights, and it strongly emits ...multi-peak broadband emissions in the far-red region peaking at 687 and 698 nm, matching well with the absorption band of phytochrome. The maximum PL intensity is achieved for the ZnAl2O4:0.8%Cr3+ phosphor annealed at 1400 °C. The lifetime and activation energy of the optimal ZnAl2O4:0.8%Cr3+ phosphor annealed at 1400 °C are 25.3 ms and 0.302 eV, respectively. Three types of far-red-emitting LEDs have been successfully fabricated by coating the optimal ZnAl2O4:0.8%Cr3+ phosphor on the surface of NUV (395 nm), violet (410 nm), and green (510 nm) chips. The chromatic coordinates of the corresponding LEDs are (0.2990; 0.2199), (0.2725; 0.1594), (0.2703; 0.5743), respectively. The quantum efficiency of the ZnAl2O4:Cr3+ phosphor excited by different LEDs is calculated and reported for the first time. The obtained results indicate that the ZnAl2O4:Cr3+ phosphor has a high potential for pc-converted plant growth LED application.
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•Single crystal far-red emitting Cr3+-doped ZnAl2O4 phosphor was synthesized by sol-gel method.•The local environment around the Cr3+ ions and the origins of all the emissions are elucidated.•Three type of pc(ZnAl2O4:Cr3+)-converted LEDs were fabricated based on 395, 410 and 520 nm chips.•The quantum efficiency of the pc-NUV-LED, pc-violet-LED and pc-green-LED are 16.2%, 15.1% and 30.4%, respectively.•ZnAl2O3:Cr3+ phosphors have potential application in plant growth lighting.
Surveillance and outbreak reporting systems in Vietnam required improvements to function effectively as early warning and response systems. Accordingly, the Ministry of Health of Vietnam, in ...collaboration with the US Centers for Disease Control and Prevention, launched a pilot project in 2016 focusing on community and hospital event–based surveillance. The pilot was implemented in 4 of Vietnam’s 63 provinces. The pilot demonstrated that event-based surveillance resulted in early detection and reporting of outbreaks, improved collaboration between the healthcare facilities and preventive sectors of the ministry, and increased community participation in surveillance and reporting.
Mast cells (MCs) are innate immune cells with a versatile set of functionalities, enabling them to orchestrate immune responses in various ways. Aside from their known role in allergy, they also ...partake in both allograft tolerance and rejection through interaction with regulatory T cells, effector T cells, B cells and degranulation of cytokines and other mediators. MC mediators have both pro- and anti-inflammatory actions, but overall lean towards pro-fibrotic pathways. Paradoxically, they are also seen as having potential protective effects in tissue remodeling post-injury. This manuscript elaborates on current knowledge of the functional diversity of mast cells in kidney transplants, combining theory and practice into a MC model stipulating both protective and harmful capabilities in the kidney transplant setting.
Ceramic Bi0.86Nd0.14Fe1-xTixO3 (0.02 ≤ x ≤ 0.1) compounds were prepared to study the structural evolution, microstructure, and magnetic properties. The structural analysis by X-ray diffraction and ...Rietveld refinement revealed a coexistence of the polar rhombohedral (R3c symmetry) and antipolar orthorhombic (Pbam symmetry) structures over the entire composition range, while Raman scattering spectroscopy detected not only the phonon vibrations of the R3c and Pbam but also the Pbnm symmetries. The microstructure investigation showed the small and large grain size regions corresponding to the R3c and Pbam/Pbnm phases, respectively. The dependence of magnetization on the Ti concentration suggested that the weak ferromagnetism observed in the compounds arised from the intrinsic collapse of cycloidal order rather than defect-induced magnetism. The magnetic aging observed at room temperature was explained on the basic of phase switching and spin frustration at the phase boundary. The influence of phase switching induced by an external electric field on the magnetic properties was also studied to reveal the contribution of phase boundary spins to the net magnetization.
•Bi0.86Nd0.14Fe1-xTixO3 samples were synthesized by solid-state reaction method.•A complex phase mixture of the rhombohedral and double orthorhombic structures was observed.•The magnetic aging was induced by the phase switching and spin frustration at the phase boundary.•The intimate connection of electric field-induced phase switching and magnetic properties was studied.
The chemical composition of PM2.5 was monitored simultaneously at two sites, one in a general area of the city center and one at a roadside, in Hanoi, Vietnam, during August 2019–July 2020 using 220 ...daily (24 h) filter samples. PM mass, water soluble ions, trace elements, organic and elemental carbon and sugar anhydrides were measured. The annual average PM2.5 concentrations, 49 and 46 μg m−3 at the traffic and the general urban site, respectively, exceeded the national (25 μg m−3) and 2021 WHO limit values (5 μg m−3). Daily PM2.5 concentrations were the highest in winter when stagnant meteorological conditions prevailed. On average, half of the resolved mass was organic matter, of which about 40% was attributable to biomass burning, most likely rice straw field burning and domestic fuel combustion. One third of PM2.5 was secondary inorganic aerosol which was dominated by sulphate hence indicating a high contribution of stationary sources like coal combustion. The elemental carbon level was higher at the traffic site, except in April 2020 during the COVID-19 restrictions. Zinc was the most common trace element with high daily variations and large differences between the sites, and it often peaked with Cd, Cl− and Pb indicating contribution of industrial sources and/or coal combustion. The highest zinc concentrations appeared on a few days and likely originated from open burning of municipal solid waste. It appeared that scattered open waste and biomass burning, as well as coal combustion, are important sources causing spikes of PM2.5 pollution in Hanoi above the general levels caused by routine industrial and traffic sources, especially during stagnant winter days. Source contributions were further studied with positive matrix factorization producing six source factors: traffic (12%), local secondary inorganic aerosol (SIA, 18%), biomass burning (19%), industry (9%), long-range transported SIA (25%) and dust (17%).
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•Highest daily concentrations occurred during winter with stagnant meteorological conditions.•Half of resolved PM2.5 mass was organic matter of which about 40% attributable to biomass burning.•One third of PM2.5 mass was secondary inorganic aerosol dominated by sulphates.•With the PMF analysis following source factors were found LRT and local SIA, traffic, biomass burning, industry and dust.•During the COVID-19 lockdown period concentration of elemental carbon was halved at the traffic site.
In 2016-2017, Vietnam's Ministry of Health (MoH) implemented an event-based surveillance (EBS) pilot project in six provinces as part of Global Health Security Agenda (GHSA) efforts. This manuscript ...describes development and design of tools for monitoring and evaluation (M&E) of EBS in Vietnam.
A strategic EBS framework was developed based on the EBS implementation pilot project's goals and objectives. The main process and outcome components were identified and included input, activities, outputs, and outcome indicators. M&E tools were developed to collect quantitative and qualitative data. The tools included a supervisory checklist, a desk review tool, a key informant interview guide, a focus group discussion guide, a timeliness form, and an online acceptability survey. An evaluation team conducted field visits for assessment of EBS 5-9 months after implementation.
The quantitative data collected provided evidence on the number and type of events that were being reported, the timeliness of the system, and the event-to-signal ratio. The qualitative and subjective data collected helped to increase understanding of the system's field utility and acceptance by field staff, reasons for non-compliance with established guidelines, and other factors influencing implementation.
The use of M&E tools for the EBS pilot project in Vietnam provided data on signals and events reported, timeliness of reporting and response, perceptions and opinions of implementers, and fidelity of EBS implementation. These data were valuable for Vietnam's MoH to understand the function of the EBS program, and the success and challenges of implementing this project in Vietnam.
Zingiber officinale is a frequently used herb and food flavouring agent, commonly known as ginger. Z. officinale belongs to the Zingiberaceae family, comprising of more than 1200 species 1. In ...traditional therapeutic systems, Z. officinale is known for its various medicinal properties that give rise to the ability to cure a variety of diseases. Ginger oil is a potential commodity, but the extraction of these oils takes a long time to produce good quality essential oils. Thus, optimization work is required in the extraction process. In this study, the extraction was performed with the hydro-distillation method, which has been widely used to extract essential oils from natural plant and herbs due to its feasibility and green technology The extraction was carried out over several extraction cycles from 15 minutes until the amount of essential oil recovered is almost unchanged. The maximum yield in ginger essential oil extract achieved 0.5% from 100 g starting material. This yield was obtained on optimum temperature conditions, extraction time and water to material ratio such as 204 W, 120 min, and 1:4 mL/g. The mathematical model of essential oil extraction was constructed, which is a crucial step in the industrial plant project because it helps to understand the extraction process and to achieve optimal operating conditions. The process kinetics in this study was modeled by the first and second-order kinetic models. The kinetics of the extraction of ginger essential oil by the hydrodistillation method has demonstrated that the extraction process is based on a second model as it has been done experimentally. The second order model was satisfactorily modified, with extremely high correlation coefficients (R2= 0.99355), demonstrating that the process was successfully described.
Community event-based surveillance aims to enhance the early detection of emerging public health threats and thus build health security. The Ministry of Health of Vietnam launched a community ...event-based surveillance pilot program in 6 provinces to improve the early warning functions of the existing surveillance system. An evaluation of the pilot program took place in 2017 and 2018. Data from this evaluation were analyzed to determine which factors were associated with increased detection and reporting. Results show that a number of small, local events were detected and reported through community event-based surveillance, supporting the notion that it would also facilitate the rapid detection and reporting of potentially larger events or outbreaks. The study showed the value of supportive supervision and monitoring to sustain community health worker reporting and the importance of conducting evaluations for community event-based surveillance programs to identify barriers to effective implementation.
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