301 research outputs found
Highly pathogenic avian influenza H5N1 virus could partly be evacuated by pregnant BALB/c mouse during abortion or preterm delivery
The highly pathogenic avian influenza H5N1 virus is one of candidates for future pandemic. Since H5N1 viruses had previously been isolated only from avian species, the outbreak raised questions about the ability of these viruses to cause severe disease and death in humans. Pregnant women are at increased risk for influenza-associated illness and death. However, little is known about whether influenza viruses could transmit to the fetus through the placenta, and the effects of abortion and preterm delivery to maternal influenza infection are not well understood. We found that the H5N1 viruses could vertical transmit to the fetus through the placenta in the BALB/c mouse model, and the viruses could partly be evacuated by the pregnant mice during abortion or preterm delivery. This study may further our understanding about the transmission of this highly pathogenic avian influenza viruses, supply optimized clinical treatment method for pregnant women, and shed some light on better preventing and controlling for future potential outbreak of H5N1 influenza pandemic
Pore-scale fluid flow simulation coupling lattice Boltzmann method and pore network model
The lattice Boltzmann method and pore network model are two types of the most popular pore-scale fluid flow simulation methods. As a direct numerical simulation method, lattice Boltzmann method simulates fluid flow directly in the realistic porous structures, characterized by high computational accuracy but low efficiency. On the contrary, pore network model simulates fluid flow in simplified regular pore networks of the real porous media, which is more computationally efficient, but fails to capture the detailed pore structures and flow processes. In past few years, significant efforts have been devoted to couple lattice Boltzmann method and pore network model to simulate fluid flow in porous media, aiming to combine the accuracy of lattice Boltzmann method and efficiency of pore network model. In this mini-review, the recent advances in pore-scale fluid flow simulation methods coupling lattice Boltzmann method and pore network model are summarized, in terms of single-phase flow, quasi-static two-phase drainage flow and dynamic two-phase flow in porous media, demonstrating that coupling the lattice Boltzmann method and pore network model offers a promising and effective approach for addressing the up-scaling problem of flow in porous media.Cited as: Zhao, J., Liu, Y., Qin, F., Fei, L. Pore-scale fluid flow simulation coupling lattice Boltzmann method and pore network model. Capillarity, 2023, 7(3): 41-46. https://doi.org/10.46690/capi.2023.06.0
Regiospecific Reductive Elimination from Diaryliodonium Salts
StereoElectronic Control of Unidirectional Reductive Elimination (SECURE) is provided by the cyclophane substituent on iodine(III). Computational and experimental studies demonstrate that out of plane steric bulk strongly destabilizes the reductive elimination transition state, and leads to regiochemical control. This approach should be general for high valent main group and transition metal ions
The Construction of a Community Long-term Care Model for Home-based Elderly Individuals
With rapidly aging populations, family care functions can become weakened, and community health services often lack unified standards. A standardized and professional community home-based long-term care model (CHLCM) for the elderly is urgently needed in many regions of China and in other countries. Here, we explored the indicators of the need for a CHLCM among elderly individuals, and we constructed a CHLCM. We created and distributed a questionnaire regarding the requirement of long-term care services, based on a literature review. The two-rounds Delphi method was used, involving 20 experts who were randomly selected from among the medical universities, community health service centers, and nursing homes in Nanning, Guangxi, China. The experts’ enthusiasm rates in the questionnaire’s two rounds were 95% and 100%, respectively. The authentic coefficient of the experts’ consulting was 0.857, and that of the experts’ academic level was 0.835; the judgement coefficient was 0.880 and the familiar coefficient was 0.855. The CHLCM includes service content and an evaluation. The coordination coefficients for the two primary, eight secondary, and 29 tertiary indicators were 0.200, 0.386, and 0.184, respectively (p<0.05). The experts’ enthusiasm and authority were high. The coordination of the experts’ agreement was sufficient, and the analysis results were reliable. The CHLCM includes 29 items that provide a foundation and references for the formulation of concrete indicators and subsequent research
An Optimized Real-Time PCR to Avoid Species-/Tissue-Associated Inhibition for H5N1 Detection in Ferret and Monkey Tissues
The real-time PCR diagnostics for avian influenza virus H5N1 in tissue specimens are often suboptimal, since naturally occurring PCR inhibitors present in samples, or unanticipated match of primer to unsequenced species' genome. With the principal aim of optimizing the SYBR Green real-time PCR method for detecting H5N1 in ferret and monkey (Chinese rhesus macaque) tissue specimens, we screened various H5N1 gene-specific primer pairs and tested their ability to sensitively and specifically detect H5N1 transcripts in the infected animal tissues, then we assessed RNA yield and quality by comparing Ct values obtained from the standard Trizol method, and four commonly used RNA isolation kits with small modifications, including Roche High Pure, Ambion RNAqueous, BioMIGA EZgene, and Qiagen RNeasy. The results indicated that a single primer pair exhibited high specificity and sensitivity for H5N1 transcripts in ferret and monkey tissues. Each of the four kits and Trizol reagent produced high-quality RNA and removed all or nearly all PCR inhibitors. No statistically significant differences were found between the Ct values from the isolation methods. So the optimized SYBR Green real-time PCR could avoid species- or tissue-associated PCR inhibition in detecting H5N1 in ferret and monkey tissues, including lung and small intestine
Unprecedented Directing Group Ability of Cyclophanes in Arene Fluorinations with Diaryliodonium Salts
For the first time it is shown that exceptionally electron-rich arene rings can be fluorinated exclusively during the reductive elimination reactions of diaryliodonium fluorides. The 5-methoxy[2.2]paracyclophan-4-yl directing group simultaneously reduces unproductive aryne chemistry and eliminates ligand exchange reactions by a combination of steric and electronic effects. Use of the cyclophane directing group permits an unprecedented degree of control in fluorination reactions of diaryliodonium salts.
Includes Supporting Information (50 pp.
Droplet evaporation in finite-size systems: Theoretical analysis and mesoscopic modeling
The classical D^{2}-Law states that the square of the droplet diameter decreases linearly with time during its evaporation process, i.e., D^{2} (t) = D^{2}_{0} - Kt, where D_{0} is the droplet initial diameter and K is the evaporation constant. Though the law has been widely verified by experiments, considerable deviations are observed in many cases. In this work, a revised theoretical analysis of the single droplet evaporation in finite-size open systems is presented for both two-dimensional (2D) and 3D cases. Our analysis shows that the classical D^{2}-Law is only applicable for 3D large systems (L ≫ D_{0}), L is the system size), while significant deviations occur for small (L ≤ 5D_{0}) and/or 2D systems. Theoretical solution for the temperature field is also derived. Moreover, we discuss in detail the proper numerical implementation of droplet evaporation in finite-size open systems by the mesoscopic lattice Boltzmann method (LBM). Taking into consideration shrinkage effects and an adaptive pressure boundary condition, droplet evaporation in finite-size 2D/3D systems with density ratio up to 328 within a wide parameter range (K = [0.003, 0.18] in lattice units) is simulated, and remarkable agreement with the theoretical solution is achieved, in contrast to previous simulations. The present work provides insights into realistic droplet evaporation phenomena and their numerical modeling using diffuse-interface methods.
Improved Arene Fluorination Methodology for I(III) Salts
The use of low polarity aromatic solvents (benzene or toluene) and/or the removal of inorganic salts results in dramatically improved yields of fluorinated arenes from diaryliodonium salts. This methodology is shown to “scale down” to the conditions used typically for radiotracer synthesis
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