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1.
Angew Chem Int Ed Engl ; : e202403980, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38588065

RESUMO

Electrochemical reduction of CO2 and nitrate offers a promising avenue to produce valuable chemicals through the using of greenhouse gas and nitrogen-containing wastewater. However, the generally proposed reaction pathway of concurrent CO2 and nitrate reduction for urea synthesis requires the catalysts to be both efficient in both CO2 and nitrate reduction, thus narrowing the selection range of suitable catalysts. Herein, we demonstrate a distinct mechanism in urea synthesis, a tandem NO3- and CO2 reduction, in which the surface amino species generated by nitrate reduction play the role to capture free CO2 and subsequent initiate its activation. When using the TiO2 electrocatalyst derived from MIL-125-NH2, it intrinsically exhibits low activity in aqueous CO2 reduction, however, in the presence of both nitrate and CO2, this catalyst achieves an excellent urea yield rate of 43.37 mmolï½¥g-1ï½¥h-1 and a Faradaic efficiency of 48.88% at -0.9 V vs. RHE in a flow cell. Even at a low CO2 level of 15%, the Faradaic efficiency of urea synthesis remains robust at 42.33%. The tandem reduction procedure was further confirmed by in-situ spectroscopies and theoretical calculations. This research provides new insights into the selection and design of electrocatalysts for urea synthesis.

2.
Water Res ; 256: 121575, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38636121

RESUMO

According to stoichiometric homeostasis theory, eutrophication is expected to increase the dominance of submerged macrophytes with low homeostatic regulation coefficients (H) relative to those with high H values, ultimately reducing macrophyte community stability. However, empirical evidence supporting this hypothesis is limited. In this study, we conducted a three-year tracking survey (seven sampling events) at 81 locations across three regions of Erhai Lake. We assessed the H values of submerged macrophyte species, revealing significant H values for phosphorus (P) and strong associations of HP values (range: 1.58-2.94) with species and community stability. Moreover, in plots simultaneously containing the dominant high-HP species, Potamogeton maackianus, and its low-HP counterpart, Ceratophyllum demersum, we explored the relationships among eutrophication, interspecific interaction shifts, and community dynamics. As the environmental P concentration increased, the dominance of P. maackianus decreased, while that of C. demersum increased. This shift coincided with reductions in community HP and stability. Our study underpins the effectiveness of H values for forecasting interspecific interactions among submerged macrophytes, thereby clarifying how eutrophication contributes to the decline in stability of the submerged macrophyte community.

3.
NPJ Vaccines ; 9(1): 65, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38514651

RESUMO

Lumpy skin disease virus (LSDV) is a poxvirus that mainly affects cattle and can lead to symptoms such as severe reduction in milk production as well as infertility and mortality, which has resulted in dramatic economic loss in affected countries in Africa, Europe, and Asia. In this study, we successfully isolated two strains of LSDV from different geographical regions in China. Comparative genomic analyses were performed by incorporating additional LSDV whole genome sequences reported in other areas of Asia. Our analyses revealed that LSDV exhibited an 'open' pan-genome. Phylogenetic analysis unveiled distinct branches of LSDV evolution, signifying the prevalence of multiple lineages of LSDV across various regions in Asia. In addition, a reporter LSDV expressing eGFP directed by a synthetic poxvirus promoter was generated and used to evaluate the cell tropism of LSDV in various mammalian and avian cell lines. Our results demonstrated that LSDV replicated efficiently in several mammalian cell lines, including human A549 cells. In conclusion, our results underscore the necessity for strengthening LSD outbreak control measures and continuous epidemiological surveillance.

4.
Appl Environ Microbiol ; 90(3): e0185123, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38426790

RESUMO

Symbiotic nitrogen fixation (SNF) by rhizobia is not only the main natural bionitrogen-source for organisms but also a green process leveraged to increase the fertility of soil for agricultural production. However, an insufficient understanding of the regulatory mechanism of SNF hinders its practical application. During SNF, nifA-fixA signaling is essential for the biosynthesis of nitrogenases and electron transfer chain proteins. In the present study, the TetR regulator NffT, whose mutation increased fixA expression, was discovered through a fixA-promoter-ß-glucuronidase fusion assay performed with Rhizobium johnstonii. Real-time quantitative PCR analysis showed that nffT deletion increased the expression of symbiotic genes including nifA and fixA in nifA-fixA signaling, and fixL, fixK, fnrN, and fixN9 in fixL-fixN signaling. nffT overexpression resulted in disordered nodules and reduced nitrogen-fixing efficiency. Electrophoretic mobility shift assays revealed that NffT directly regulated the transcription of RL0091-93, which encode an ATP-binding ABC transporter predicted to be involved in carbohydrate transport. Purified His-tagged NffT bound to a 68 bp DNA sequence located -32 to -99 bp upstream of RL0091-93 and NffT deletion significantly increased the expression of RL0091-93. nffT-promoter-ß-glucuronidase fusion assay indicated that nffT expression was regulated by the cobNTS genes and cobalamin. Mutations in cobNTS significantly decreased the expression of nffT, and cobalamin restored its expression. These results revealed that NffT affects nodule development and nitrogen-fixing reaction by participating in a complex regulatory network of symbiotic and carbohydrate metabolic genes and, thus, plays a pivotal regulatory role during symbiosis of R. johnstonii-Pisum sativum.IMPORTANCESymbiotic nitrogen fixation (SNF) by rhizobia is a green way to maintain soil fertility without causing environmental pollution or consuming chemical energy. A detailed understanding of the regulatory mechanism of this complex process is essential for promoting sustainable agriculture. In this study, we discovered the TetR-type regulator NffT, which suppressed the expression of fixA in Rhizobium johnstonii. Furthermore, NffT was confirmed to play pleiotropic roles in R. johnstonii-Pisum sativum symbiosis; specifically, it inhibited rhizobial growth, nodule differentiation, and nitrogen-fixing reactions. We revealed that NffT indirectly affected R. johnstonii-P. sativum symbiosis by participating in a complex regulatory network of symbiotic and carbohydrate metabolic genes. Furthermore, cobalamin, a chemical molecule, was reported for the first time to be involved in TetR-type protein transcription during symbiosis. Thus, NffT identification connects SNF regulation with genetic, metabolic, and chemical signals and provides new insights into the complex regulation of SNF, laying an experimental basis for the targeted construction of rhizobial strains with highly efficient nitrogen-fixing capacity.


Assuntos
Rhizobium , Rhizobium/genética , Rhizobium/metabolismo , Fixação de Nitrogênio/genética , Ervilhas , Glucuronidase/metabolismo , Carboidratos , Nitrogênio/metabolismo , Solo , Vitamina B 12/metabolismo , Simbiose/genética
5.
Molecules ; 28(21)2023 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-37959727

RESUMO

Acetaminophen (APAP)-induced liver injury is a common hepatic disease resulting from drug abuse. Few targeted treatments are available clinically nowadays. The flower bud of Rosa rugosa has a wide range of biological activities. However, it is unclear whether it alleviates liver injury caused by APAP. Here, we prepared an ethanol extract of Rosa rugosa (ERS) and analyzed its chemical profile. Furthermore, we revealed that ERS significantly ameliorated APAP-induced apoptosis and ferroptosis in AML-12 hepatocytes and dampened APAP-mediated cytotoxicity. In AML-12 cells, ERS elevated Sirt1 expression, boosted the LKB1/AMPK/Nrf2 axis, and thereby crippled APAP-induced intracellular oxidative stress. Both EX527 and NAM, which are chemically unrelated inhibitors of Sirt1, blocked ERS-induced activation of LKB1/AMPK/Nrf2 signaling. The protection of ERS against APAP-triggered toxicity in AML-12 cells was subsequently abolished. As expression of LKB1 was knocked down, ERS still upregulated Sirt1 but failed to activate AMPK/Nrf2 cascade or suppress cytotoxicity provoked by APAP. Results of in vivo experiments showed that ERS attenuated APAP-caused hepatocyte apoptosis and ferroptosis and improved liver injury and inflammation. Consistently, ERS boosted Sirt1 expression, increased phosphorylations of LKB1 and AMPK, and promoted Nrf2 nuclear translocation in the livers of APAP-intoxicated mice. Hepatic transcriptions of HO-1 and GCLC, which are downstream antioxidant genes of Nrf2, were also significantly increased in response to ERS. Our results collectively indicated that ERS effectively attenuates APAP-induced liver injury by activating LKB1/AMPK/Nrf2 cascade. Upregulated expression of Sirt1 plays a crucial role in ERS-mediated activation of LKB1.


Assuntos
Doença Hepática Crônica Induzida por Substâncias e Drogas , Doença Hepática Induzida por Substâncias e Drogas , Leucemia Mieloide Aguda , Rosa , Animais , Camundongos , Acetaminofen/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Rosa/metabolismo , Transdução de Sinais , Doença Hepática Crônica Induzida por Substâncias e Drogas/metabolismo , Sirtuína 1/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Fígado , Hepatócitos , Estresse Oxidativo , Leucemia Mieloide Aguda/metabolismo
6.
Materials (Basel) ; 16(19)2023 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-37834523

RESUMO

The peak dilation angle is an important mechanical feature of rock discontinuities, which is significant in assessing the mechanical behaviour of rock masses. Previous studies have shown that the efficiency and accuracy of traditional experimental methods and analytical models in determining the shear dilation angle are not completely satisfactory. Machine learning methods are popular due to their efficient prediction of outcomes for multiple influencing factors. In this paper, a novel hybrid machine learning model is proposed for predicting the peak dilation angle. The model incorporates support vector regression (SVR) techniques as the primary prediction tools, augmented with the grid search optimization algorithm to enhance prediction performance and optimize hyperparameters. The proposed model was employed on eighty-nine datasets with six input variables encompassing morphology and mechanical property parameters. Comparative analysis is conducted between the proposed model, the original SVR model, and existing analytical models. The results show that the proposed model surpasses both the original SVR model and analytical models, with a coefficient of determination (R2) of 0.917 and a mean absolute percentage error (MAPE) of 4.5%. Additionally, the study also reveals that normal stress is the most influential mechanical property parameter affecting the peak dilation angle. Consequently, the proposed model was shown to be effective in predicting the peak dilation angle of rock discontinuities.

7.
Phys Chem Chem Phys ; 25(38): 26203-26210, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37740356

RESUMO

Charge separation in organic solar cells is a long-lasting and heavily debated issue. Here, we use the surface hopping method based on the Pariser-Parr-Pople (PPP) Hamiltonian and configuration interaction singles (CIS) approximation to simulate the charge separation process in an organic donor-acceptor system. The system is composed of one donor polymer chain and four acceptor polymer chains, and they are all stacked face-to-face. We let the system to relax from a photoexcited state, and then we observed that the electron is transferred from the donor chain to different acceptor chains and the hole is left on the donor chain, forming polaron pairs with different electron-hole distances. By performing statistical analysis on a number of trajectories, we found that the electron and the hole are fully separated before the system relaxes to its lowest excited state. The yield of free charges shows a significant dependence on the donor-acceptor band offset which provides the driving force for charge separation, while showing negligible dependence on the photoexcitation energy. The external electric field has a remarkable effect on the yield of free charges.

8.
Phys Chem Chem Phys ; 25(34): 23100-23110, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37602670

RESUMO

The complexity of modeling flexible crystals, such as ZIF-8, mainly stems from the handling of intramolecular interactions. Numerous force fields have been proposed in the literature to describe the interactions between atoms in ZIF-8. We employ seven force fields to examine the structure and dynamic behavior of water molecules confined in ZIF-8, with the aim of investigating the impact of force fields on simulation results. Various structural characterization methods consistently indicate that the choice of different force fields has quantitative effects but no qualitative effects on the structural characteristics of confined water. Additionally, the force fields do not impact the qualitative description of the diffusion mechanism. Both mean-square displacement and van Hove autocorrelation function reveal two characteristic movements of water molecules diffusing in ZIF-8: a short-time intra-cavity hopping process and a long-time inter-cavity hopping process. However, the framework flexibility is found to play a crucial role in determining the order of spatial arrangement and local structure, self-diffusion coefficient and reorientational dynamics of confined water. Specifically, the DREIDING force field gives rise to an unrealistic stiff framework, enhancing the order of spatial arrangement and diminishing the local ordered structure of confined water. Meanwhile, it results in much slower translational and reorientational dynamics. Hence, the general DREIDING force field cannot be considered for providing a quantitative description of the water structure and dynamics.

9.
World J Microbiol Biotechnol ; 39(10): 278, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37582899

RESUMO

Milbemycins (MILs), a group of 16-membered insecticidal macrocylic lactones, are widely used as the biological pesticide and the precursors of semi-synthetic veterinary drugs. Polyketide synthases (PKSs), which require phosphopantetheinyl transferases (PPTases) to activate their ACP domains from apo forms to holo forms, catalyze the backbone biosynthesis of MILs. Here we found there was a complex phosphopantetheinylation network mediated by five putative PPTases in Streptomyces bingchenggensis. Repression mutants of PpA27 and PpA62 via CRISPRi both produced significantly lower yields of MILs than that of the control strain. Repression mutant of PpA68 led to abolishment of the pigment production. MILs production was significantly enhanced by PpA27 overexpression, while not by the overexpression of other PPTases. PpA27 was thus proved a dedicated post-translational enzyme to activate PKSs involved in the MILs biosynthesis. MILs titer was further enhanced by co-overexpression of PpA27 and MilR, the pathway­specific transcriptional activator of MIL biosynthetic gene cluster. When PpA27 and MilR were co-overexpressed in the industrial S. bingchenggensis HMB, MILs production was increased by 40.5%. These results indicated that tuning the antibiotic biosynthetic pathway by co-engineering transcriptional regulation network and post-translational phosphopantetheinylation network is an effective strategy for antibiotic production improvement.


Assuntos
Antibacterianos , Macrolídeos , Macrolídeos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Policetídeo Sintases/genética
10.
Proc Natl Acad Sci U S A ; 120(35): e2304242120, 2023 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-37607234

RESUMO

Zoonotic poxviruses such as mpox virus (MPXV) continue to threaten public health safety since the eradication of smallpox. Vaccinia virus (VACV), the prototypic poxvirus used as the vaccine strain for smallpox eradication, is the best-characterized member of the poxvirus family. VACV encodes a serine protease inhibitor 1 (SPI-1) conserved in all orthopoxviruses, which has been recognized as a host range factor for modified VACV Ankara (MVA), an approved smallpox vaccine and a promising vaccine vector. FAM111A (family with sequence similarity 111 member A), a nuclear protein that regulates host DNA replication, was shown to restrict the replication of a VACV SPI-1 deletion mutant (VACV-ΔSPI-1) in human cells. Nevertheless, the detailed antiviral mechanisms of FAM111A were unresolved. Here, we show that FAM111A is a potent restriction factor for VACV-ΔSPI-1 and MVA. Deletion of FAM111A rescued the replication of MVA and VACV-ΔSPI-1 and overexpression of FAM111A significantly reduced viral DNA replication and virus titers but did not affect viral early gene expression. The antiviral effect of FAM111A necessitated its trypsin-like protease domain and DNA-binding domain but not the PCNA-interacting motif. We further identified that FAM111A translocated into the cytoplasm upon VACV infection by degrading the nuclear pore complex via its protease activity, interacted with VACV DNA-binding protein I3, and promoted I3 degradation through autophagy. Moreover, SPI-1 from VACV, MPXV, or lumpy skin disease virus was able to antagonize FAM111A by prohibiting its nuclear export. Our findings reveal the detailed mechanism by which FAM111A inhibits VACV and provide explanations for the immune evasive function of VACV SPI-1.


Assuntos
Poxviridae , Varíola , Vaccinia , Animais , Bovinos , Humanos , Vírus Vaccinia/genética , Inibidores de Serino Proteinase , Proteínas Virais/genética , Replicação do DNA , Especificidade de Hospedeiro , DNA Viral , Replicação Viral , Receptores Virais
11.
Brief Bioinform ; 24(5)2023 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-37480553

RESUMO

Most life activities in organisms are regulated through protein complexes, which are mainly controlled via Protein-Protein Interactions (PPIs). Discovering new interactions between proteins and revealing their biological functions are of great significance for understanding the molecular mechanisms of biological processes and identifying the potential targets in drug discovery. Current experimental methods only capture stable protein interactions, which lead to limited coverage. In addition, expensive cost and time consuming are also the obvious shortcomings. In recent years, various computational methods have been successfully developed for predicting PPIs based only on protein homology, primary sequences of protein or gene ontology information. Computational efficiency and data complexity are still the main bottlenecks for the algorithm generalization. In this study, we proposed a novel computational framework, HNSPPI, to predict PPIs. As a hybrid supervised learning model, HNSPPI comprehensively characterizes the intrinsic relationship between two proteins by integrating amino acid sequence information and connection properties of PPI network. The experimental results show that HNSPPI works very well on six benchmark datasets. Moreover, the comparison analysis proved that our model significantly outperforms other five existing algorithms. Finally, we used the HNSPPI model to explore the SARS-CoV-2-Human interaction system and found several potential regulations. In summary, HNSPPI is a promising model for predicting new protein interactions from known PPI data.


Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Algoritmos , Sequência de Aminoácidos , Benchmarking
12.
Angew Chem Int Ed Engl ; 62(20): e202300469, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-36932854

RESUMO

Herein we report the vital role of spin polarization in proton-transfer-mediated water oxidation over a magnetized catalyst. During the electrochemical oxygen evolution reaction (OER) over ferrimagnetic Fe3 O4 , the external magnetic field induced a remarkable increase in the OER current, however, this increment achieved in weakly alkaline pH (pH 9) was almost 20 times that under strongly alkaline conditions (pH 14). The results of the surface modification experiment and H/D kinetic isotope effect investigation confirm that, at weakly alkaline pH, during the nucleophilic attack of FeIV =O by molecular water, the magnetized Fe3 O4 catalyst polarizes the spin states of the nucleophilic attacking intermediates. The spin-enhanced singlet O-H cleavage and triplet O-O bonding occur synergistically, which promotes the O2 generation more significantly than the strongly alkaline case involving only spin-enhanced O-O bonding.

13.
J Phys Chem A ; 127(12): 2787-2794, 2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-36924022

RESUMO

Atomically dispersed catalysts (ADCs) with a well-defined structure are theoretically desirable for a high-selectivity photocatalytic reaction. However, achieving high product selectivity remains a practical challenge for ADCs-based photocatalysts. Herein, we reveal a spin polarization effect on achieving high product selectivity (95.0%) toward the photocatalytic nitrobenzene (PhNO2) hydrogenation to aniline (PhNH2) on atomically dispersed Fe site-loaded graphitic carbon nitride (Fe/g-C3N4). In combination with the Gibbs free energy diagram and electronic structure analysis, the origin of the photocatalytic performance is attributed not only to the strong metal-support interaction between the Fe site and g-C3N4, but more importantly to the strong spin polarization effect that promotes the potential-determining step (PDS) of *PhNO to *PhNOH. This work could be helpful for the design of ADCs-based photocatalysts in view of the spin polarization effect.

14.
J Hazard Mater ; 449: 131040, 2023 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-36821906

RESUMO

Cd accumulation in crops has become a global environmental problem because it endangers human health. Screening for microorganisms that can reduce Cd accumulation in crops is a possible measure to address this issue. However, success has been limited, and most previous work did not involve bacteria. In the present study, a strain of N-fixing bacteria (Burkholderia spp.) that exhibits high levels of Cd tolerance was screened. The ability of this bacterium to reduce Cd in rapeseed was then assessed in sterile hydroponic and open soil culture systems. In the hydroponic system, the Burkholderia inoculum promoted Cd fixation in rapeseed roots and thus reduced Cd enrichment in aboveground edible tissues (leaves). The mechanisms were related to increased activity of pectin methylesterase in root cell walls, and the transformation of the chemical form of root Cd from "active" (NaCl-extracted) to "inert" (HCl-extracted and residual Cd) states. Additionally, Burkholderia accelerated plant growth, thus shortening the period in which the plant is available for Cd absorption. In the soil culture system, Burkholderia also reduced Cd enrichment in rapeseed leaves in the presence of other microorganisms. Thus, the bacterial strain shows potential for broad application for reducing the accumulation of Cd in crops.


Assuntos
Brassica napus , Brassica rapa , Poluentes do Solo , Humanos , Cádmio/toxicidade , Raízes de Plantas/química , Produtos Agrícolas , Solo , Poluentes do Solo/análise
15.
Angew Chem Int Ed Engl ; 62(10): e202216717, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36597591

RESUMO

Herein, we fabricated a π-π stacking hybrid photocatalyst by combining two two-dimensional (2D) materials: g-C3 N4 and a Cu-porphyrin metal-organic framework (MOF). After an aerobic photocatalytic pretreatment, this hybrid catalyst exhibited an unprecedented ability to photocatalytically reduce CO2 to CO and CH4 under the typical level (20 %) of O2 in the air. Intriguingly, the presence of O2 did not suppress CO2 reduction; instead, a fivefold increase compared with that in the absence of O2 was observed. Structural analysis indicated that during aerobic pretreatment, the Cu node in the 2D-MOF moiety was hydroxylated by the hydroxyl generated from the reduction of O2 . Then the formed hydroxylated Cu node maintained its structure during aerobic CO2 reduction, whereas it underwent structural alteration and was reductively devitalized in the absence of O2 . Theoretical calculations further demonstrated that CO2 reduction, instead of O2 reduction, occurred preferentially on the hydroxylated Cu node.

16.
Materials (Basel) ; 16(2)2023 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-36676326

RESUMO

The rock or rock mass in engineering often contains joints, fractures, voids, and other defects, which are the root cause of local or overall failure. In response to most of the current constitutive models that fail to simulate the nonlinear fracture compaction deformation in the whole process of rock failure, especially brittle rocks, a piecewise constitutive model was proposed to represent the global constitutive relation of rocks in this study, which was composed of the fracture compaction empirical model and the damage statistical constitutive model. The fracture empirical compaction model was determined by fitting the expressions of fracture closure curves of various rocks, while the rock damage evolution equation was derived underpinned by the fracture growth. According to the effective stress concept and strain equivalence hypothesis, the rock damage constitutive model was deduced. The model parameters of the fracture compaction empirical model and damage statistical constitutive model were all calculated by the geometrical characteristics of the global axial stress-strain curve to guarantee that the models are continuous and smooth at the curve intersection, which is also simple and ready to program. Finally, the uniaxial compression test data and the triaxial compression test data of different rocks in previous studies were employed to validate the models, and the determination coefficient was used to measure the accuracy. The results showed great consistency between the model curves and test data, especially in the pre-peak stage.

17.
Membranes (Basel) ; 12(4)2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35448387

RESUMO

The realistic resistance zone of water and salt molecules to transport across a TFC-RO membrane is the topmost polyamide nanofilm. The existence of hollow voids in the fully aromatic polyamide (PA) film gives its surface ridge-and-valley morphologies, which confuses the comprehensions of the definition of the PA thickness. The hollow voids, however, neither participate in salt-water separation nor hinder water penetrating. In this paper, the influence of intrinsic thickness (single wall thickness) of the PA layer on water permeability was studied by adjusting the concentration of reacting monomers. It confirms that the true permeation resistance of water molecules originates from the intrinsic thickness portion of the membrane. The experimental results show that the water permeability constant decreases from 3.15 ± 0.02 to 2.74 ± 0.10 L·m-2·h-1·bar-1 when the intrinsic thickness of the membrane increases by 9 nm. The defects on the film surface generate when the higher concentration of MPD is matched with the relatively low concentration of TMC. In addition, the role of MPD and TMC in the micro-structure of the PA membrane was discussed, which may provide a new way for the preparation of high permeability and high selectivity composite reverse osmosis membranes.

18.
Phys Chem Chem Phys ; 24(16): 9557-9563, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35394001

RESUMO

With the discovery of the chiral-induced spin selectivity (CISS) effect, it has been recognized that spin and structural spin-orbit coupling (SOC) play important roles in the electro-optical properties of chiral materials. We redefine the spin-dependent current and magnetic moment operators to include chiral-induced SOC in a helical polymer and deduce optical absorption and circular dichroism (CD) formulae. The fine structure in the optical spectra is calculated for a helical polymer described with the tight-binding model. The effects of both the electron orbit and spin on the optical absorption and CD are discussed. Our investigations demonstrate that the synergy between the electron orbit and spin will contribute to higher-sensitivity circularly polarized light (CPL) detection.

19.
Phys Chem Chem Phys ; 24(8): 5220-5232, 2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35167632

RESUMO

A classical atomistic simulation study is reported for the microscopic structure and dynamics of a water/methanol mixture confined in flexible nanoporous zeolitic imidazolate framework ZIF-8. Both the radial density distribution and vivid two-dimensional density profile demonstrate that methanol molecules can roughly be viewed as "embedded" between two layers of water molecules to form a "sandwich" structure. The reason for the formation of such a specific structure is explained based on the hydrogen-bonding state and the strength of various hydrogen bonds. The investigation of guest molecular diffusion shows that the self-diffusion coefficient of confined water is generally one to two orders of magnitude smaller than that of bulk water. In addition, the dependence of the self-diffusion coefficient on loading is non-monotonic: the self-diffusion coefficient firstly shows a significant increase and then decreases at higher loading. Moreover, both the structure and dynamics of the hydrogen bond (HB) network of confined water molecules are investigated in a spatially resolved manner. The results indicate that both the HB structure and dynamics of water molecules near the ZIF-8 surface deviate significantly from those of bulk water. However, while water molecules located at the pore center are relatively similar to bulk water molecules with respect to the HB structure, they exhibit strong slowdown in HB dynamics when compared with bulk water. This simulation study elucidates in detail the structural and dynamical properties of a water/methanol mixture in nanoscopic ZIF-8 confinement, which is expected to provide a deep insight into the role of porous fillers, such as ZIF-8, in improving the performance of the dehydration of alcohols via pervaporation and other related processes.

20.
Transbound Emerg Dis ; 69(3): 1438-1448, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-33872465

RESUMO

Since 2014, highly pathogenic avian influenza H5N6 viruses have been responsible for outbreaks in poultry. In this study, four H5N6 virus strains were isolated from faecal samples of sick white ducks and dead chickens in Shandong in 2019. These H5N6 viruses were triple-reassortant viruses that have not been previously characterized. Their HA genes were derived from the H5 viruses and were closely related to the vaccine strain Re-11. Their NA genes all fell into the N6-like lineage and the internal gene were derived from H5N1 and H9N2 viruses. They all showed high pathogenicity in mice and caused lethal infection with high rates of transmission in chickens. Moreover, the SPF chickens inoculated with the currently used H5 (Re-11 and Re-12 strains)/H7 (H7-Re-2 strain) trivalent inactivated vaccines in China were completely protected from these four H5N6 viruses. Our study indicated the necessity of continued surveillance for H5 influenza A viruses and the importance of timely update of vaccine strains in poultry industry.


Assuntos
Virus da Influenza A Subtipo H5N1 , Vírus da Influenza A Subtipo H9N2 , Vacinas contra Influenza , Influenza Aviária , Doenças dos Roedores , Animais , Galinhas , Virus da Influenza A Subtipo H5N1/genética , Camundongos , Filogenia , Aves Domésticas , Vacinas de Produtos Inativados
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