Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 120(48): e2309506120, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-37983498

RESUMO

African swine fever virus (ASFV), a devastating pathogen to the worldwide swine industry, mainly targets macrophage/monocyte lineage, but how the virus enters host cells has remained unclear. Here, we report that ASFV utilizes apoptotic bodies (ApoBDs) for infection and cell-cell transmission. We show that ASFV induces cell apoptosis of primary porcine alveolar macrophages (PAMs) at the late stage of infection to productively shed ApoBDs that are subsequently swallowed by neighboring PAMs to initiate a secondary infection as evidenced by electron microscopy and live-cell imaging. Interestingly, the virions loaded within ApoBDs are exclusively single-enveloped particles that are devoid of the outer layer of membrane and represent a predominant form produced during late infection. The in vitro purified ApoBD vesicles are capable of mediating virus infection of naive PAMs, but the transmission can be significantly inhibited by blocking the "eat-me" signal phosphatidyserine on the surface of ApoBDs via Annexin V or the efferocytosis receptor TIM4 on the recipient PAMs via anti-TIM4 antibody, whereas overexpression of TIM4 enhances virus infection. The same treatment however did not affect the infection by intracellular viruses. Importantly, the swine sera to ASFV exert no effect on the ApoBD-mediated transmission but can partially act on the virions lacking the outer layer of membrane. Thus, ASFV has evolved to hijack a normal cellular pathway for cell-cell spread to evade host responses.


Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Vesículas Extracelulares , Suínos , Animais , Vírus da Febre Suína Africana/fisiologia , Macrófagos/metabolismo , Monócitos/metabolismo , Vesículas Extracelulares/metabolismo
2.
Small ; 19(16): e2207487, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36693783

RESUMO

Benefiting from the proton's small size and ultrahigh mobility in water, aqueous proton batteries are regarded as an attractive candidate for high-power and ultralow-temperature energy storage devices. Herein, a new-type C4 N polymer with uniform micropores and a large specific surface area is prepared by sulfuric acid-catalyzed ketone amine condensation reaction and employed as the electrode of proton batteries. Multi-walled carbon nanotubes (MWCNT) are introduced to induce the in situ growth of C4 N, and reaped significantly enhanced porosity and conductivity, and thus better both room- and low-temperature performance. When coupled with MnO2 @Carbon fiber (MnO2 @CF) cathode, MnO2 @CF//C4 N-50% MWCNT full battery shows unprecedented cycle stability with a capacity retention of 98% after 11 000 cycles at 10 A g-1 and even 100% after 70 000 cycles at 20 A g-1 . Additionally, a novel anti-freezing electrolyte (5 m H2 SO4  + 0.5 m MnSO4 ) is developed and showed a high ionic conductivity of 123.2 mS cm-1 at -70 °C. The resultant MnO2 @CF//C4 N-50% MWCNT battery delivers a specific capacity of 110.5 mAh g-1 even at -70 °C at 1 A g-1 , the highest in all reported proton batteries under the same conditions. This work is expected to offer a package solution for constructing high-performance ultralow-temperature aqueous proton batteries.

3.
Proc Natl Acad Sci U S A ; 115(32): E7478-E7485, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-30038016

RESUMO

Protein kinases are dynamic molecular switches that sample multiple conformational states. The regulatory subunit of PKA harbors two cAMP-binding domains [cyclic nucleotide-binding (CNB) domains] that oscillate between inactive and active conformations dependent on cAMP binding. The cooperative binding of cAMP to the CNB domains activates an allosteric interaction network that enables PKA to progress from the inactive to active conformation, unleashing the activity of the catalytic subunit. Despite its importance in the regulation of many biological processes, the molecular mechanism responsible for the observed cooperativity during the activation of PKA remains unclear. Here, we use optical tweezers to probe the folding cooperativity and energetics of domain communication between the cAMP-binding domains in the apo state and bound to the catalytic subunit. Our study provides direct evidence of a switch in the folding-energy landscape of the two CNB domains from energetically independent in the apo state to highly cooperative and energetically coupled in the presence of the catalytic subunit. Moreover, we show that destabilizing mutational effects in one CNB domain efficiently propagate to the other and decrease the folding cooperativity between them. Taken together, our results provide a thermodynamic foundation for the conformational plasticity that enables protein kinases to adapt and respond to signaling molecules.


Assuntos
Domínio Catalítico/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Dobramento de Proteína , Transdução de Sinais/fisiologia , Regulação Alostérica/fisiologia , Domínio Catalítico/genética , AMP Cíclico/química , Proteínas Quinases Dependentes de AMP Cíclico/química , Ensaios Enzimáticos , Simulação de Dinâmica Molecular , Mutação , Pinças Ópticas , Ligação Proteica/fisiologia , Domínios Proteicos/fisiologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-31611352

RESUMO

A novel, plasmid-mediated, high-level tigecycline resistance tet(X) gene variant, tet(X5), was detected in a clinical Acinetobacter baumannii isolate from China in 2017. Tet(X5) shows 84.5% and 90.5% amino acid identity to Tet(X3) and Tet(X4), respectively, with similar binding sites and a comparable affinity for tetracyclines. The tet(X5)-containing plasmid could only be transferred to A. baumannii via electrotransformation. This report follows the recent study describing the identification of tet(X3) and tet(X4).


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , China , Transferência Genética Horizontal , Humanos , Testes de Sensibilidade Microbiana , Modelos Genéticos , Modelos Moleculares , Simulação de Acoplamento Molecular , Plasmídeos/genética , Resistência a Tetraciclina/genética , Tetraciclinas/farmacologia , Tigeciclina/farmacologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-31085517

RESUMO

The rapid dissemination of the macrolide resistance gene erm(B) will likely compromise the efficacy of macrolides as the treatment of choice for campylobacteriosis. More importantly, erm(B) is always associated with several multidrug resistance genomic islands (MDRGIs), which confer resistance to multiple other antimicrobials. Continuous monitoring of the emergence of erm(B) and analysis of its associated genetic environments are crucial for our understanding of macrolide resistance in Campylobacter In this study, 290 Campylobacter isolates (216 Campylobacter coli isolates and 74 Campylobacter jejuni isolates) were obtained from 1,039 fecal samples collected in 2016 from pigs and chickens from three regions of China (344 samples from Guangdong, 335 samples from Shanghai, and 360 samples from Shandong). Overall, 74 isolates (72 C. coli isolates and 2 C. jejuni isolates) were PCR positive for erm(B). Combined with data from previous years, we observed a trend of increasing prevalence of erm(B) in C. coli Pulsed-field gel electrophoresis analyses suggested that both clonal expansion and horizontal transmission were involved in the dissemination of erm(B) in C. coli, and three novel types of erm(B)-associated MDRGIs were identified among the isolates. Furthermore, 2 erm(B)-harboring C. jejuni isolates also contained an aminoglycoside resistance genomic island and a multidrug-resistance-enhancing efflux pump, encoded by RE-cmeABC Antimicrobial susceptibility testing showed that most of the isolates were resistant to all clinically important antimicrobial agents used for the treatment of campylobacteriosis. These findings suggest that the increasing prevalence of erm(B)-associated MDRGIs might further limit treatment options for campylobacteriosis.


Assuntos
Antibacterianos/farmacologia , Campylobacter/genética , Ilhas Genômicas/genética , Macrolídeos/farmacologia , Campylobacter/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Farmacorresistência Bacteriana Múltipla/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Testes de Sensibilidade Microbiana , Sequenciamento Completo do Genoma
6.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 36(5): 777-784, 2019 Oct 25.
Artigo em Zh | MEDLINE | ID: mdl-31631626

RESUMO

The tilted supine position has been evaluated to be one of the significantly effective approaches to prevent bedsore of the patients in the bedridden state. Thus, it has deeply positive influences that in view of dynamics this study explores how the position works. Based on the anatomical theories, this study formulates the human dynamic model. Furthermore, the dynamic simulation of three usual postures in tilted supine position including lying on back, lying with one knee bent and lying with the upper and lower limb on one side lifted is carried out. Therefore, the changes of the three driving forces named as chest force, waist force and thigh force in the tilted supine position can be observed. In order to verify the validity of this simulation, this study obtains the electromyogram measurements of ectopectoralis, external obliques and thigh muscles which are respectively close to the chest, waist and thigh by conducting the human force measurements experiment. The result revealed that in terms of range and trend, the experimental data and simulation's data were consistent. In conclusion, the changes of these muscles in the supine position movements are researched efficiently by both this experiment and the dynamic simulation. Besides, the result is crucially key to find the mechanism of human's tilted supine position movements.


Assuntos
Modelos Anatômicos , Movimento , Postura , Decúbito Dorsal , Fenômenos Biomecânicos , Eletromiografia , Humanos , Músculo Esquelético/fisiologia
7.
Sci Rep ; 14(1): 11470, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38769119

RESUMO

In the process of coal-filling mining, the gangue fly-ash slurry (GFS) needs to be transported over a long distance to reach the gobs. The abrupt closure of the valve during the transportation of GFS can result in a water hammer that significantly endangers the stability and safety of the pipeline transport system. To study the fluctuations in pressure induced by abrupt closure of the valve, experiments on the rheological parameters of gangue-coal ash slurry were conducted. Transient numerical simulations were carried out using the computational fluid dynamics method for various valve closing times. The results indicate that, with the increase of slurry concentration, the yield stress of the slurry significantly increases. When the concentration exceeds 76%, the increase in yield stress reaches 38.4% and 35.1%, respectively. Upon valve closure, the internal pressure of the slurry in the pipeline exhibits periodic dynamic oscillations. As the duration of valve closure increases, the frequency of periodic water hammer events decreases. The maximum water hammer pressure caused by valve closure decreases with the increasing distance between the valve and the closure point. At the same time, the intensity of maximum water hammer pressure fluctuations increases with the increase in slurry concentration and flow velocity in the pipeline. The results can provide references for water hammer protection and pipeline selection during the transportation of backfill slurry in mining.

8.
Adv Mater ; 36(26): e2403489, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38556648

RESUMO

Rechargeable aqueous proton batteries with small organic molecule anodes are currently considered promising candidates for large-scale energy storage due to their low cost, stable safety, and environmental friendliness. However, the practical application is limited by the poor cycling stability caused by the shuttling of soluble organic molecules between electrodes. Herein, a cell separator is modified by a GO-casein-Cu2+ layer with a brick-and-mortar structure to inhibit the shuttling of small organic molecules. Experimental and calculation results indicate that, attributed to the synergistic effect of physical blocking of casein molecular chains and electrostatic and coordination interactions of Cu2+, bulk dissolution and shuttling of multiple small molecules can be inhibited simultaneously, while H+ transfer across the separators is not almost affected. With the protection of the GO-casein-Cu2+ separator, soluble small molecules, such as diquinoxalino[2,3-a:2',3'-c]phenazine,2,3,8,9,14,15-hexacyano (6CN-DQPZ) exhibit a high reversible capacity of 262.6 mA h g-1 and amazing stability (capacity retention of 92.9% after 1000 cycles at 1 A g-1). In addition, this strategy is also proved available to other active conjugated small molecules, such as indanthrone (IDT), providing a general green sustainable strategy for advancing the use of small organic molecule electrodes in proton cells.

9.
Talanta ; 276: 126193, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38735244

RESUMO

Di(2-ethylhexyl)phthalate (DEHP) is commonly released from plastics in aqueous environment, which can disrupt endocrine system and cause adverse effects on public health. There is a pressing need to highly sensitive detect DEHP. Herein, a near-infrared (NIR) light-driven lab-on-paper cathodic photoelectrochemical aptasensing platform integrated with AgInS2/Cu2O/FeOOH photocathode and "Y"-like ternary conjugated DNA nanostructure-mediated "ON-OFF" catalytic switching of hemin monomer-to-dimer was established for ultrasensitive DEHP detection. Profiting from the collaborative roles of the effective photosensitization of NIR-response AgInS2 and the fast hole extraction of FeOOH, the NIR light-activated AgInS2/Cu2O/FeOOH photocathode generated a markedly enhanced photocathodic signal. The dual hemin-labelled "Y"-like ternary conjugated DNA nanostructures made the hemin monomers separated in space and they maintained highly active to catalyze in situ generation of electron acceptors (O2). The hemin monomers were relocated in close proximity with the help of target-induced allosteric change of DNA nanostructures, which could spontaneously dimerize into catalytically inactive hemin dimers and fail to mediate electron acceptors generation, resulting in a decreased photocathodic signal. Therefore, the ultrasensitive DEHP detection was realized with a linear response range of 1 pM-500 nM and a detection limit of 0.39 pM. This work rendered a promising prototype to construct powerful paper-based photocathodic aptasensing system for sensitive and accurate screening of DEHP in aqueous environment.


Assuntos
Cobre , Dietilexilftalato , Técnicas Eletroquímicas , Eletrodos , Raios Infravermelhos , Processos Fotoquímicos , Cobre/química , Técnicas Eletroquímicas/métodos , Dietilexilftalato/química , Dietilexilftalato/análise , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Papel , Prata/química , Limite de Detecção , Índio/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
10.
MAbs ; 16(1): 2365891, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38889315

RESUMO

Integrins are cell surface receptors that mediate the interactions of cells with their surroundings and play essential roles in cell adhesion, migration, and homeostasis. Eight of the 24 integrins bind to the tripeptide Arg-Gly-Asp (RGD) motif in their extracellular ligands, comprising the RGD-binding integrin subfamily. Despite similarity in recognizing the RGD motif and some redundancy, these integrins can selectively recognize RGD-containing ligands to fulfill specific functions in cellular processes. Antibodies against individual RGD-binding integrins are desirable for investigating their specific functions, and were selected here from a synthetic yeast-displayed Fab library. We discovered 11 antibodies that exhibit high specificity and affinity toward their target integrins, i.e. αVß3, αVß5, αVß6, αVß8, and α5ß1. Of these, six are function-blocking antibodies and contain a ligand-mimetic R(G/L/T)D motif in their CDR3 sequences. We report antibody-binding specificity, kinetics, and binding affinity for purified integrin ectodomains, as well as intact integrins on the cell surface. We further used these antibodies to reveal binding preferences of the αV subunit for its 5 ß-subunit partners: ß6 = ß8 > ß3 > ß1 = ß5.


Assuntos
Saccharomyces cerevisiae , Humanos , Saccharomyces cerevisiae/genética , Cadeias beta de Integrinas/imunologia , Cadeias beta de Integrinas/química , Cadeias beta de Integrinas/metabolismo , Cadeias beta de Integrinas/genética , Integrina alfaV/imunologia , Integrina alfaV/metabolismo , Integrinas/imunologia , Integrinas/metabolismo , Biblioteca de Peptídeos , Técnicas de Visualização da Superfície Celular , Ligação Proteica , Especificidade de Anticorpos
11.
bioRxiv ; 2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38328192

RESUMO

Eight of the 24 integrin heterodimers bind to the tripeptide Arg-Gly-Asp (RGD) motif in their extracellular ligands, and play essential roles in cell adhesion, migration, and homeostasis. Despite similarity in recognizing the RGD motif and some redundancy, these integrins can selectively recognize RGD-containing ligands including fibronectin, vitronectin, fibrinogen, nephronectin and the prodomain of the transforming growth factors to fulfill specific functions in cellular processes. Subtype-specific antibodies against RGD-binding integrins are desirable for investigating their specific functions. In this study, we discovered 11 antibodies that exhibit high specificity and affinity towards integrins αVß3, αVß5, αVß6, αVß8, and α5ß1 from a synthetic yeast-displayed Fab library. Of these, 6 are function-blocking antibodies containing an R(G/L/T) D motif in their CDR3 sequences. We report antibody binding specificity, kinetics, and binding affinity for purified integrin ectodomains as well as intact integrins on the cell surface. We further employed these antibodies to reveal binding preferences of the αV subunit for its 5 ß-subunit partners: ß6=ß8>ß3>ß1=ß5.

12.
Nanomaterials (Basel) ; 14(7)2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38607147

RESUMO

Field emission (FE) necessitates cathode materials with low work function and high thermal and electrical conductivity and stability. To meet these requirements, we developed FE cathodes based on high-quality wrinkled multilayer graphene (MLG) prepared using the bubble-assisted chemical vapor deposition (B-CVD) method and investigated their emission characteristics. The result showed that MLG cathodes prepared using the spin-coating method exhibited a high field emission current density (~7.9 mA/cm2), indicating the excellent intrinsic emission performance of the MLG. However, the weak adhesion between the MLG and the substrate led to the poor stability of the cathode. Screen printing was employed to prepare the cathode to improve stability, and the influence of a silver buffer layer was explored on the cathode's performance. The results demonstrated that these cathodes exhibited better emission stability, and the silver buffer layer further enhanced the comprehensive field emission performance. The optimized cathode possesses low turn-on field strength (~1.5 V/µm), low threshold field strength (~2.65 V/µm), high current density (~10.5 mA/cm2), and good emission uniformity. Moreover, the cathode also exhibits excellent emission stability, with a current fluctuation of only 6.28% during a 4-h test at 1530 V.

13.
Front Microbiol ; 15: 1328177, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38419627

RESUMO

African swine fever (ASF) caused by the African swine fever virus (ASFV) is a fatal and highly contagious disease of domestic pigs characterized by rapid disease progression and death within 2 weeks. How the immune cells respond to acute ASFV infection and contribute to the immunopathogenesis of ASFV has not been completely understood. In this study, we examined the activation, apoptosis, and functional changes of distinct immune cells in domestic pigs following acute infection with the ASFV CADC_HN09 strain using multicolor flow cytometry. We found that ASFV infection induced broad apoptosis of DCs, monocytes, neutrophils, and lymphocytes in the peripheral blood of pigs over time. The expression of MHC class II molecule (SLA-DR/DQ) on monocytes and conventional DCs as well as CD21 expression on B cells were downregulated after ASFV infection, implying a potential impairment of antigen presentation and humoral response. Further examination of CD69 and ex vivo expression of IFN-γ on immune cells showed that T cells were transiently activated and expressed IFN-γ as early as 5 days post-infection. However, the capability of T cells to produce cytokines was significantly impaired in the infected pigs when stimulated with mitogen. These results suggest that the adaptive cellular immunity to ASFV might be initiated but later overridden by ASFV-induced immunosuppression. Our study clarified the cell types that were affected by ASFV infection and contributed to lymphopenia, improving our understanding of the immunopathogenesis of ASFV.

14.
Natl Sci Rev ; 11(4): nwae045, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38545446

RESUMO

Organic materials with rich active sites are good candidates of high-capacity anodes in aqueous batteries, but commonly low utilization of active sites limits their capacity. Herein, two isomers, symmetric and asymmetric hexaazatribenzanthraquinone (s-HATBAQ and a-HATBAQ), with rich active sites have been synthesized in a controllable manner. It has been revealed for the first time that a sulfuric acid catalyst can facilitate the stereoselective formation of s-HATBAQ. Attributed to the reduced steric hindrance in favor of proton insertion as well as the amorphous structure conducive to electrochemical dynamics, s-HATBAQ exhibits 1.5 times larger specific capacity than a-HATBAQ. Consequently, the electrode of s-HATBAQ with 50% reduced graphene oxide (s-HATBAQ-50%rGO) delivers a record high specific capacity of 405 mAh g-1 in H2SO4 electrolyte. Moreover, the assembled MnO2//s-HATBAQ-50%rGO aqueous proton full batteries show an exceptional cycling stability at 25°C and can maintain ∼92% capacity after 1000 cycles at 0.5 A g-1 at -80°C. This work demonstrates the controllable synthesis of isomers, showcases a wide-temperature-range prototype proton battery and highlights the significance of precise molecular structure modulation in organic energy storage.

16.
Brain Res ; 1803: 148230, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36608758

RESUMO

This event-related potentials study explored the processing of Mandarin short passives. We used a syntactic violation paradigm to compare the processing of two auxiliary phrases (i.e., a verb-modifier di-phrase and a noun-modifier de-phrase). In the control condition, the syntactic hierarchy of the di-phrase was lower than that of the de-phrase. In the violation condition, the low-level violation was created by replacing di with de in the auxiliary phrase, while the high-level violation was created by replacing de with di in the auxiliary phrase. The ERP data showed that the noun-modifier elicited the greater left anterior negativity (LAN) and the P600 than the verb-modifier, in both the control condition and the violation condition. We also observed that the LAN induced by the verb-modifier phrase was greater in the control condition than that in the violation condition, while the LAN induced by the noun-modifier was greater in the violation condition than that in the control condition. These results suggested that the greater cortical LAN-P600 might differentiate the high-level hierarchy from the low-level hierarchy. In addition, we tentatively claimed that given the same predicate argument structure, long passives might be the default representational mode of short passives (generally, a constructional alternation might be activated during the processing of the target structure).


Assuntos
Compreensão , Semântica , Compreensão/fisiologia , Idioma , Potenciais Evocados/fisiologia , Inibidores de Proteínas Quinases , Eletroencefalografia
17.
Environ Sci Pollut Res Int ; 30(9): 24687-24707, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36346525

RESUMO

The mechanical characteristics of cemented paste backfill (CPB) are significantly influenced by the loading rate (LR) and initial defects. Therefore, the CPB with prefabricated fracture (PF, PFCPB) was prepared, and uniaxial compressive strength (UCS) tests considering LR and acoustic emission (AE) monitoring were performed. The particle flow code (PFC2D) was introduced to analyze the mesoscopic crack evolution of the filling body, and the moment tensor theory was used to invert the AE signals characteristics. The results show that as the PF angle increased, the UCS and elastic modulus (EM) of PFCPB decreased and then increased, and the 30° PF was the turning point. The mechanical properties of PFCPB were deteriorated by the presence of PF. Meanwhile, the mechanical properties of PFCPB were positively correlated with the LR. The stress-strain curve of PFCB (excluding 90°) showed bimodal curves. After the UCS test, the macro crack of PFCPB sprouted at the tip of PF or converged toward PF. PFCPB mainly suffered from shear failure, accompanied by a few tensile failures. Numerical simulation results showed that the crack initiation stress of PFCPB was reduced by the PF. The number of cracks first dropped and then gradually increased when the PF angle was enhanced, while gradually increased with the LR increased. Meanwhile, the mesoscopic AE characteristics of CPB were strongly in line with the test results. The AE events of 0 ~ 60° PFCPB experienced two slow rising periods and rapid rising periods. The temporal and spatial distribution characteristics of AE corresponded to the crack evolution trend. The PF was prone to stress concentration, especially at the tip and upper and lower surfaces of 0 ~ 45° PF, resulting in rapid crack initiation and reducing the energy storage limit and mechanical behavior of 0 ~ 45° PFCPB. The increasing LR (within a certain range) was in favor of improving the mechanical behavior of the filling body. The research results can provide a basic reference for the stability evaluation of the filling body with initial defects.


Assuntos
Acústica , Ansiedade , Força Compressiva
18.
Environ Sci Pollut Res Int ; 30(15): 45295-45314, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36705829

RESUMO

Low-cost and underutilized plant fibers can affect the mechanical behavior of cementitious materials such as cemented tailings backfill (CTB). This paper attempts to explore the mechanical properties and damage evolution characteristics of rice straw fiber (RFS)-reinforced CTB (RSFCTB) from the perspective of energy. A series of mechanical and microscopic tests were carried out on CTB and RSFCTB samples. On this basis, the energy evolution law and of the filling body under different stress paths were analyzed. Meanwhile, a damage variable based on dissipation energy was established, and the damage evolution process of the filling body was discussed. The results show that uniaxial compressive strength (UCS) of filling body first grew and then dropped with the enhancement of RSF content, and indirect tensile strength (ITS) was positively correlated with RSF content. Scanning electron microscope showed that RSF was encapsulated by hydration products, which promoted the bridging effect of RSF. The bridging effect of RSF improved the integrity of RSFCTB after compression failure and resulted in bending and asymmetric tensile cracks after tensile failure. The energy storage limit and dissipation energy of the filling body under different stress paths were enhanced due to the incorporation of RSF. The damage curve based on dissipation energy showed three stages of slow, steady, and fast damage under compressive loading. The damage curve of RSFCTB was located below CTB depending on the crack arresting effect of RSF. Moreover, the damage curve under tensile load shows three stages: slow, stable damage, and sudden increase in damage. The damage value of RSFCTB at the mutation point was increased, and the ability of RSFCTB to resist tensile damage was enhanced. The energy evolution and acoustic emission parameters were combined, and their development trends were similar, which proved that it was reasonable to characterize the damage of filling body based on the dissipated energy.


Assuntos
Oryza , Acústica , Força Compressiva , Mutação , Estruturas Vegetais
19.
Animals (Basel) ; 13(7)2023 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-37048502

RESUMO

African swine fever (ASF) is a devastating infectious disease in domestic pigs caused by African swine fever virus (ASFV) with a mortality rate of about 100%. However, the understanding of the interaction between ASFV and host is still not clear. In this study, the expression differences and functional analysis of microRNA (miRNA) in porcine peripheral blood lymphocytes of ASFV infected pigs and healthy pigs were compared based on Illumina high-throughput sequencing, then the GO and KEGG signal pathways were analyzed. The miRNA related to immunity and inflammation were screened, and the regulatory network of miRNA-mRNA was drawn. A total of 70 differentially expressed miRNAs were found (p ≤ 0.05). Of these, 45 were upregulated and 25 were downregulated in ASFV-infected pigs vs. healthy pigs. A total of 8179 mRNA genes targeted by these 70 differentially expressed miRNA were predicted, of which 1447 mRNA genes were targeted by ssc-miR-2320-5p. Five differentially expressed miRNA were validated by RT-qPCR, which were consistent with the RNA-Seq results. The GO analysis revealed that a total of 30 gene functions were significantly enriched, including 7 molecular functions (MF), 13 cellular components (CC), and 10 biological processes (BP). The KEGG enrichment analysis revealed that the differentially expressed genes were significantly enriched in pathways related to immunity, inflammation, and various metabolic processes, in which a total of two downregulated miRNAs after infection and eight upregulated miRNAs related to immunity and inflammation were screened in ASFV-infected pigs vs. healthy pigs. The network of miRNA-mRNA showed that the mRNA target genes were strongly regulated by ssc-miR-214, ssc-miR-199b-3p, and ssc-miR-199a-3p. The mRNA target genes were enriched into the MAPK signaling pathway, Toll-like receptor signaling pathway, TNF signaling pathway, and IL-17 signaling pathway by using a KEGG enrichment analysis. Therefore, ASFV could regulate immunity and metabolism-related pathways in infected pigs by inducing differential expression of miRNAs. These results provided a new basis for further elucidating the interactions between ASFV and the host as well as the immunity regulation mechanisms of ASFV, which will be conducive to better controlling ASF.

20.
Sensors (Basel) ; 12(4): 4421-30, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22666037

RESUMO

1-[(Anthracen-9-yl)methylene] thiosemicarbazide shows weak fluorescence due to a photo-induced electron transfer (PET) process from the thiosemicarbazide moiety to the excited anthracene. The anthracene emission can be recovered via protonation of the amine as the protonated aminomethylene as an electron-withdrawing group that suppresses the PET process. Similarly, chelation between the ligand and the metal ions can also suppress the PET process and results in a fluorescence enhancement (CHEF). When solvents are introduced as the third control, a molecular 2:1 multiplexer is constructed to report selectively the inputs. Therefore, a molecular 2:1 multiplexer is realized in a simple molecular system.


Assuntos
Semicarbazidas/química , Espectrometria de Fluorescência , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Ultravioleta
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA