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•We have developed a facile post-method to prepare three-dimensional porous NiO microspheres with high specific surface area.•The porous NiO microspheres has highly sensitive and ...markedly selective toward H2S gas at ultralow concentration.•Such a potential gas sensing strategy can be easily extended to other metal oxides.
In this report, the porous NiO microspheres were fabricated by a post-simple route using α-Ni(OH)2 microflowers as precursor that were synthesized by a hydrothermal method without using surfactants. The three-dimensional (3D) NiO microspheres ranging from 2 to 10 μm in diameters composes of connected NiO nanoparticles, results in the sintering and phase transformation from primary α-Ni(OH)2 nanosheets to NiO nanoparticles during thermal procedures. The porous NiO microspheres-based sensor was tested with some toxic and flammable gases including H2S, NH3, H2, and CO. The hierarchical porous sensors exhibit high selectivity and sensitivity toward H2S in comparison with other interfering gases. The results may be related to some factors such as the catalytic effect of NiO on the oxidation of hydrosulfide, a moderately chemical affinity between Ni and S, and well-aligned porous architectures. The results exhibit the potential of hierarchical porous NiO microspheres as a gas-sensing material for excellent H2S detection.
Episparis tortuosalis
(Moore, The Lepidoptera of Ceylon, L. Reeve Company, London, 1867) (Lepidoptera: Erebidae: Pangraptini) is a significant pest defoliating
Chukrasia tabularis
plantations in ...Vietnam. Since 2013 the geographic range of the pest has increased from one to nine provinces. Field surveys in 9 provinces in 2021 showed that feeding by
E. tortuosalis
larvae resulted in the damage incidence ranging from 28.5 to 100% and the damage index from 0.82 to 3.66. This study illustrates the male and female morphology and genitalia of this pest from Vietnam. Further studies are recommended to help develop an integrated pest management plan for this pest.
•Facile method has employed to prepare mesoporous Co3O4 nanochains with high specific surface area.•The Co3O4 nanochains has highly sensitive and selective toward H2S gas with rapid response.•Such a ...potential gas sensing strategy can be easily extended to other metal oxides.
In this paper, cobalt carbonate hydroxide (Co(CO3)0.5(OH)..11H2O) nanowires were successfully fabricated by a simple hydrothermal route without using surfactants and by subsequent heat treatment in air at 600 °C for 5 h to obtain mesoporous Co3O4 nanochains. As-synthesized nanochains with length of several micrometers consisted of well-linked Co3O4 nanoparticles with an average size of 50 nm. The sensor based on mesoporous Co3O4 nanochains was used to detect flammable and toxic gases, including H2S, NH3, CO, and H2. Results showed potential of mesoporous Co3O4 nanochains as sensor material for detection of hydrogen sulfides at low concentration with rapid response.
Roller burnishing is an alternative approach to enhance surface properties under plastic deformation and most investigations focused on optimizing process parameters. However, the impacts of ...operating parameters of the minimum quantity lubrication (MQL) system on the surface properties have not been considered. The roller burnishing process is widely applied to fabricate high-pressure bushings and crankshafts with superior quality, while the MQL system is extensively employed to facilitate different machining operations for saving lubricant usage, decreasing negative impacts on the environment, and protecting worker’s health. The purpose of this investigation is to select the optimal MQL system factors, including the nozzle diameter (
D
), impingement angle (
I
), flow rate (
Q
), and air pressure (
P
) for decreasing the maximum profile peak height of the roughness (MAR) and improving Vickers hardness (VH) for the roller burnishing process. The optimal artificial neural network (ANN) model was proposed to render the relations between the optimizing inputs and burnishing responses. An efficiently evolutionary technique entitled multi-objective glowworm swarm optimization (MOGSO) was utilized to produce a set of feasible solutions. The VIKOR method was employed to determine the best optimal solution. The results revealed that the 4–10–2 architecture of the developed ANN models efficiently described the burnishing performances and precisely predicted the response values. The optimal outcomes of the
D
,
I
,
Q
, and
P
were 1.5 mm, 45 deg., 130 ml/h, and 0.6 MPa, while the improvements in the MAR and VH were 17.0% and 14.0%, respectively, as compared to the common values used. The proposed approach comprising the ANN, MOGSO, and VIKOR could be considered as a powerful technique to deal with the complicated optimizing issue for the roller burnishing operation. The obtained finding could be expected as a significant contribution to enhancement in the machining quality for the roller burnishing process under the MQL condition.
Despite the discovery of several closely related viruses in bats, the direct evolutionary progenitor of SARS-CoV-2 has not yet been identified. In this study, we investigated potential animal sources ...of SARS-related coronaviruses using archived specimens from Sunda pangolins (
) and Chinese pangolins (
) confiscated from the illegal wildlife trade, and from common palm civets (
) raised on wildlife farms in Viet Nam. A total of 696 pangolin and civet specimens were screened for the presence of viral RNA from five zoonotic viral families and from Sarbecoviruses using primers specifically designed for pangolin coronaviruses. We also performed a curated data collection of media reports of wildlife confiscation events involving pangolins in Viet Nam between January 2016 and December 2020, to illustrate the global pangolin supply chain in the context of Viet Nam where the trade confiscated pangolins were sampled for this study. All specimens from pangolins and civets sampled along the wildlife supply chains between February 2017 and July 2018, in Viet Nam and tested with conventional PCR assays designed to detect flavivirus, paramyxovirus, filovirus, coronavirus, and orthomyxovirus RNA were negative. Civet samples were also negative for Sarbecoviruses, but 12 specimens from seven live pangolins confiscated in Hung Yen province, northern Viet Nam, in 2018 were positive for Sarbecoviruses. Our phylogenetic trees based on two fragments of the RdRp gene revealed that the Sarbecoviruses identified in these pangolins were closely related to pangolin coronaviruses detected in pangolins confiscated from the illegal wildlife trade in Yunnan and Guangxi provinces, China. Our curated data collection of media reports of wildlife confiscation events involving pangolins in Viet Nam between January 2016 and December 2020, reflected what is known about pangolin trafficking globally. Pangolins confiscated in Viet Nam were largely in transit, moving toward downstream consumers in China. Confiscations included pangolin scales sourced originally from Africa (and African species of pangolins), or pangolin carcasses and live pangolins native to Southeast Asia (predominately the Sunda pangolin) sourced from neighboring range countries and moving through Viet Nam toward provinces bordering China.
Agricultural production is the primary source of income and food security for rural households in many deltas of the world. However, the sustainability of farm livelihoods is under threat, due to the ...impacts of climate change and environmental pressure, including shifting hydrological regimes, droughts, water pollution, land subsidence and riverbank erosion. This study evaluated the livelihood sustainability and vulnerability of triple rice farmers on the floodplains of the Vietnam Mekong Delta (VMD). We focused on the perceptions of rice farmers, based on a survey of 300 farmers. Increasing temperatures, drought, water pollution and sediment shortages were the four factors considered by farmers to have the most impact on their agricultural livelihoods. We analyzed farmers’ capacity to sustain their livelihoods and adapt to the changing environment. Results show relatively low vulnerability of rice farmers overall, though many of those surveyed reported very low incomes from rice production. Factors of most concern to farmers were rising temperatures and more frequent droughts. Farmers were already taking steps to adapt, for example, increasing production inputs and investing more labor time, as well as switching production methods. Yet, our findings suggest that policymakers and scientists have a role to play in developing more sustainable adaptation paths. The research clarifies the livelihood vulnerability of triple rice farmers on the VMD floodplains, while more generally contributing to the body of literature on farming and climate change and environmental pressure.
Aims
Anthrax is reported with frequency but poorly understood in Southeast Asian countries including Vietnam. In Vietnam, anthrax surveillance is national. However, case detection, prevention, and ...control are implemented locally at the provincial level. Here, we describe the epidemiological characteristics, identify spatial clusters of human anthrax, and compare the variation in livestock anthrax vaccine coverage to disease incidence in humans and livestock using historical data in Son La province, Vietnam (2003–2020).
Methods and Results
Most human cases occurred between April and September. Most of the patients were male, aged 15–54 years old. The human cases were mainly reported by public district hospitals. There was a delay between disease onset and hospitalization of ~5 days. We identified spatial clusters of high–high incidence communes in the northern communes of the province using the local Moran's I statistic. The vaccine coverage sharply decreased across the study period. The province reported sporadic human anthrax outbreaks, while animal cases were only reported in 2005 and 2022.
Conclusions
These results suggest underreporting for human and livestock anthrax in the province. Intersectoral information sharing is needed to aid livestock vaccination planning, which currently relies on reported livestock cases. The spatial clusters identify areas for targeted surveillance and livestock vaccination, while the seasonal case data suggest prioritizing vaccination campaigns for February or early March ahead of the April peak. A regional approach for studying the role of livestock trading between Son La and neighbouring provinces in anthrax occurrence is recommended.
Three-dimensional (3D) bioprinting has become mainstream for precise and repeatable high-throughput fabrication of complex cell cultures and tissue constructs in drug testing and regenerative ...medicine, food products, dental and medical implants, biosensors, and so forth. Due to this tremendous growth in demand, an overwhelming amount of hardware manufacturers have recently flooded the market with different types of low-cost bioprinter models—a price segment that is most affordable to typical-sized laboratories. These machines range in sophistication, type of the underlying printing technology, and possible add-ons/features, which makes the selection process rather daunting (especially for a nonexpert customer). Yet, the review articles available in the literature mostly focus on the technical aspects of the printer technologies under development, as opposed to explaining the differences in what is already on the market. In contrast, this paper provides a snapshot of the fast-evolving low-cost bioprinter niche, as well as reputation profiles (relevant to delivery time, part quality, adherence to specifications, warranty, maintenance, etc.) of the companies selling these machines. Specifically, models spanning three dominant technologies—microextrusion, droplet-based/inkjet, and light-based/crosslinking—are reviewed. Additionally, representative examples of high-end competitors (including up-and-coming microfluidics-based bioprinters) are discussed to highlight their major differences and advantages relative to the low-cost models. Finally, forecasts are made based on the trends observed during this survey, as to the anticipated trickling down of the high-end technologies to the low-cost printers. Overall, this paper provides insight for guiding buyers on a limited budget toward making informed purchasing decisions in this fast-paced market.
Chukrasia tabularis A. Juss produces a valuable timber but plantations are susceptible to attack by the shoot-tip borer Hypsipyla robusta Moore. An integrated pest management (IPM) approach is ...desirable to limit the extent of damage. Therefore, this study was undertaken to evaluate the deployment of IPM measures in plantations in Vietnam. Data on tree damage and the biology of H. robusta were gathered in 4 provinces over one year and used to build an investigation schedule. Two preliminary IPM trials were then established in which Bacillus thuringiensis and Metarhizium anisopliae were applied to the foliage when the damage incidence (P%) was in the range 5–10%; and insecticides (Carbaryl, Carbosulfan) were applied when the P% exceeded 10%. In addition, larvae and pupae were removed manually over time. In the first trial, the combination of manual and biological control methods reduced the damage index (DI) of trees from 4 tolerant families by 82% compared to the untreated control plots. In the second trial using standard planting stock, application of insecticides was required to reduce the DI by 83%. Six extended IPM trials were undertaken using the same IPM protocols and these reduced the DI to the same extent as in the preliminary trials. Over an 18-month period, the deployment of IPM increased height growth by 19–22% and diameter growth by 38–41% compared to the controls. These findings highlight the value of planting improved seed and the benefit of adopting an IPM approach to manage the shoot-tip borer.
The wood-borer Bacchisa medioviolacea Breuning (Coleoptera: Cerambycidae) is identified as a major new pest of Docynia indica (Rosales: Rosaceae) orchards in the northwest mountainous provinces of ...Vietnam. The life cycle extends over two years (721.7 days ± 17.6 days), with overwintering as larvae. Adults emerge and disperse in summer. Females lay 6–12 eggs during an oviposition period of 2–3 days, and the incubation period ranges from 27 to 38 days. The larval and pupal periods take 554–701 days and 40–59 days, respectively. Adults survive for 12–23 days. In 2019, the damage incidence (P%) and the damage index (DI) in Yen Bai, Lao Cai, Lai Chau, and Dien Bien provinces ranged from 43.5% to 71.6% and 0.80 to 1.78, respectively. Further research on the distribution and host range of B. medioviolacea is required to help formulate a management strategy for this new orchard pest.
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