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1.
J Agric Food Chem ; 72(13): 7533-7545, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38527761

RESUMO

MicroRNAs are crucial regulators of gene expression in maize. However, the mechanisms through which miRNAs control internode elongation remain poorly understood. This study engineered varying levels of internode elongation inhibition, revealing that dwarfing treatments diminished gibberellin levels, curtailed cell longitudinal growth, and slowed the rate of internode elongation. Comprehensive transcriptome and miRNA profiling of the internode elongation zone showed gene expression changes that paralleled the extent of the internode length reduction. We identified 543 genes and 29 miRNAs with significant correlations to internode length, predominantly within families, including miR164 and miR396. By incorporating target gene expression levels, we pinpointed nine miRNA-mRNA pairs that are significantly associated with the regulation of the internode elongation. The inhibitory effects of these miRNAs on their target genes were confirmed through dual-luciferase reporter assays. Overexpression of miR164h in maize resulted in increased internode and cell length, suggesting a novel genetic avenue for manipulating plant stature. These miRNAs may also serve as precise spatiotemporal regulators for in vitro plant development.


Assuntos
MicroRNAs , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Zea mays/metabolismo , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
2.
Adv Mater ; : e2312153, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38444205

RESUMO

The presence of bacteria in tumor results in chemotherapeutic drug resistance and weakens the immune response in colorectal cancer. To overcome bacterium-induced chemotherapeutic drug resistance and potentiate antitumor immunity, herein a novel molecule Biotin-Lys(SA-Cip-OH)-Lys(SA-CPT)-Phe-Phe-Nap (Biotin-Cip-CPT-Nap) is rationally designed containing four functional motifs (i.e., a biotin motif for targeting, Phe-Phe(-Nap) motif for self-assembly, ciprofloxacin derivative (Cip-OH) motif for antibacterial effect, and camptothecin (CPT) motif for chemotherapy). Using the designed molecule, a novel strategy of intracellular enzymatic nanofiber formation and synergistic antibacterium-enhanced chemotherapy and immunotherapy is achieved. Under endocytosis mediated by highly expressed biotin receptor in colorectal cancer cell membrane and the catalysis of highly expressed carboxylesterase in the cytoplasm, this novel molecule can be transformed into Biotin-Nap, which self-assembled into nanofibers. Meanwhile, antibiotic Cip-OH and chemotherapeutic drug CPT are released, overcoming bacterium-induced drug resistance and enhancing the therapeutic efficacy of immunotherapy towards colorectal cancer. This work offers a feasible strategy for the design of novel multifunctional prodrugs to improve the efficiency of colorectal cancer treatment.

3.
Comput Struct Biotechnol J ; 23: 559-565, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38274998

RESUMO

Escherichia coli (E. coli) has become a particular concern due to the increasing incidence of antimicrobial resistance (AMR) observed worldwide. Using machine learning (ML) to predict E. coli AMR is a more efficient method than traditional laboratory testing. However, further improvement in the predictive performance of existing models remains challenging. In this study, we collected 1937 high-quality whole genome sequencing (WGS) data from public databases with an antimicrobial resistance phenotype and modified the existing workflow by adding an attention mechanism to enable the modified workflow to focus more on core single nucleotide polymorphisms (SNPs) that may significantly lead to the development of AMR in E. coli. While comparing the model performance before and after adding the attention mechanism, we also performed a cross-comparison among the published models using random forest (RF), support vector machine (SVM), logistic regression (LR), and convolutional neural network (CNN). Our study demonstrates that the discriminative positional colors of Chaos Game Representation (CGR) images can selectively influence and highlight genome regions without prior knowledge, enhancing prediction accuracy. Furthermore, we developed an online tool (https://github.com/tjiaa/E.coli-ML/tree/main) for assisting clinicians in the rapid prediction of the AMR phenotype of E. coli and accelerating clinical decision-making.

4.
Nat Commun ; 14(1): 8062, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38052827

RESUMO

Hollow multi-shell mesoporous metal-organic framework (MOF) particles with accessible compartmentalization environments, plentiful heterogeneous interfaces, and abundant framework diversity are expected to hold great potential for catalysis, energy conversion, and biotechnology. However, their synthetic methodology has not yet been established. In this work, a facile dual-template-directed successive assembly approach has been developed for the preparation of monodisperse hollow multi-shell mesoporous MOF (UiO-66-NH2) particles through one-step selective etching of successively grown multi-layer MOFs with alternating two types of mesostructured layers. This strategy enables the preparation of hollow multi-shell mesoporous UiO-66-NH2 nanostructures with controllable shell numbers, accessible mesochannels, large pore volume, tunable shell thickness and chamber sizes. The methodology relies on creating multiple alternating layers of two different mesostructured MOFs via dual-template-directed successive assembly and their difference in framework stability upon chemical etching. Benefiting from the highly accessible Lewis acidic sites and the accumulation of reactants within the multi-compartment architecture, the resultant hollow multi-shell mesoporous UiO-66-NH2 particles exhibit enhanced catalytic activity for CO2 cycloaddition reaction. The dual-template-directed successive assembly strategy paves the way toward the rational construction of elaborate hierarchical MOF nanoarchitectures with specific physical and chemical features for different applications.

5.
ACS Nano ; 17(24): 25061-25069, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38085532

RESUMO

Colloidal metal-organic framework (MOF) nanoparticles, with tailored asymmetric nanoarchitectures and hierarchical meso-/microporosities, have significant implications in high-performance nanocatalysts, nanoencapsulation carriers, and intricate assembly architectures. However, the methodology that could achieve precise control over the anisotropic growth of asymmetric MOF particles with tailored distributions of meso- and microporous regions has not yet been established. In this study, we introduce a facile anisotropic interface successive assembly approach to synthesize asymmetric core-shell MOF (ZIF-67) nanobowls with worm-like mesopores in the core and intrinsic micropores in the shell. Our synthesis pathway relies on anisotropic nucleation of mesoporous MOF nanohemispheres on emulsion interfaces through the cooperative assembly of surfactants and MOF precursors. This is followed by the growth of microporous MOF layers on both interfaces of mesoporous cores and emulsion droplets, resulting in a hierarchically porous core-shell nanostructure. By utilizing this multi-interface-driven approach, we enable the creation of diverse geometries and distributions of mesopores and micropores in asymmetric MOF nanoarchitectures. The obtained bowl-like meso-/microporous core-shell ZIF-67 particles exhibit enhanced catalytic activity for CO2 cycloaddition, attributed to reactant accumulation within the bowl-like architecture, active site accessibility in the open mesoporous core, and improved structural stability. Overall, our study provides insights and inspiration for exploring the intricate asymmetric nanostructures of hierarchically porous MOFs with diverse potential applications.

6.
Adv Healthc Mater ; : e2303472, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37985951

RESUMO

Current molecular photoacoustic (PA) probes are designed with either stimulus-turned "on" or assembly-enhanced signals to trace biological analytes/events. PA probes based on the nature-derived click reaction between 2-cyano-6-aminobenzothiazole (CBT) and cysteine (Cys) (i.e., CBT-Cys click reaction) possess both "turn-on" and "enhanced" PA signals; and thus, should have higher sensitivity. Nevertheless, such PA probes, particularly those for sensitive imaging of tumor hypoxia, remain scarce. Herein, a PA probe NI-Cys(StBu)-Dap(IR780)-CBT (NI-C-CBT) is rationally designed, which after being internalized by hypoxic tumor cells, is cleaved by nitroreductase under the reduction condition to yield cyclic dimer C-CBT-Dimer to turn the PA signal "ON" and subsequently assembled into nanoparticles C-CBT-NPs with additionally enhanced PA signal ("Enhanced"). NI-C-CBT exhibits 1.7-fold "ON" and 3.2-fold overall "Enhanced" PA signals in vitro. Moreover, it provides 1.9-fold and 2.8-fold overall enhanced PA signals for tumor hypoxia imaging in HeLa cells and HeLa tumor-bearing mice, respectively. This strategy is expected to be widely applied to design more "smart" PA probes for sensitive imaging of important biological events in vivo in near future.

7.
Opt Express ; 31(16): 26685-26696, 2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37710523

RESUMO

The metalens has vast applications in biomedicine and industrial manufacturing due to their ultrathin structure and vital ability to manipulate the properties of light waves for long-infrared systems. However, it is difficult for metalens to achieve the confocal function with high focusing efficiency, wide wavelength bandwidth, and low structural complexity. Here, we propose and experimentally demonstrate an all-silicon dielectric metalens composed of arrays of minimalist meta-atoms with a single rectangular nanopillar arranged on a periodic square lattice substrate, which realizes the confocal function of the orthogonal-linear-polarized light with wavelengths of 10.6 µm and 9.3 µm, with focusing efficiencies of 64.94% and 60.03%, respectively. Also, it reveals nearly the diffraction-limited focusing performance. In addition, the metalens can realize precise long-infrared thermal imaging. Moreover, the proposed metalens is compatible with the standard complementary metal oxide semiconductor processes, which can effectively reduce the manufacturing cost and provide a feasible solution for developing planar integrated multifunctional micro-nanophotonic devices in the long-infrared field.

8.
Anal Chem ; 95(39): 14511-14515, 2023 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-37721425

RESUMO

Photoacoustic (PA) imaging of urokinase-type plasminogen activator (uPA) activity in vivo holds high promise for early diagnosis of breast cancer. Molecular probes with resisted fluorescence (FL) emission for enhanced PA signals of uPA activity have not been reported. Herein, we proposed a molecular probe Cbz-Gly-Gly-Arg-Phe-Phe-IR775 (Z-GGRFF-IR775) which, upon uPA cleavage, assembled into nanoparticles FF-IR775-NP with quenched fluorescence but enhanced PA signals. Experimental results validated that, upon uPA activation, Z-GGRFF-IR775 exhibited 4.7-fold, 4.1-fold, and 2.9-fold higher PA signals over those in uPA inhibitor-treated control groups in vitro, in MDA-MB-231 cells, and in a tumor-bearing mouse model, respectively. We anticipate that this probe could be applied for highly sensitive PA imaging of uPA activity in early stage malignant tumors in the near future.


Assuntos
Neoplasias , Técnicas Fotoacústicas , Animais , Camundongos , Ativador de Plasminogênio Tipo Uroquinase , Diagnóstico por Imagem , Receptores de Ativador de Plasminogênio Tipo Uroquinase
9.
ACS Omega ; 8(24): 21410-21417, 2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37360464

RESUMO

High-efficacy and regenerable antimicrobial silica granules were prepared via oxa-Michael addition between poly(vinyl alcohol) (PVA) and methylene-bis-acrylamide (MBA) under the catalysis of sodium carbonate in an aqueous solution. Diluted water glass was added, and the solution pH was adjusted to about 7 to precipitate PVA-MBA modified mesoporous silica (PVA-MBA@SiO2) granules. N-Halamine-grafted silica (PVA-MBA-Cl@SiO2) granules were achieved by adding diluted sodium hypochlorite solution. It was found that a BET surface area of about 380 m2 g-1 for PVA-MBA@SiO2 granules and a Cl+% of about 3.80% for PVA-MBA-Cl@SiO2 granules could be achieved under optimized preparation conditions. Antimicrobial tests showed that the as-prepared antimicrobial silica granules were capable of about a 6-log inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 10 min of contact. Furthermore, the as-prepared antimicrobial silica granules can be recycled many times due to the excellent regenerability of their N-halamine functional groups and can be saved for a long time. With the above-mentioned advantages, the granules have potential applications in water disinfection.

10.
Nano Lett ; 23(13): 6178-6183, 2023 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-37363812

RESUMO

Apoptosis, with a hallmark of upregulated protease Caspase-3, has been frequently imaged with various probes to reveal the therapeutic efficiencies of different drugs. However, activatable molecular probes with programmable self-assembling behaviors that enable enhanced T1-weighted magnetic resonance imaging (MRI) of apoptosis remain scarce. Herein, taking advantage of a CBT-Cys click reaction, we rationally designed a Caspase-3-activatable self-assembling probe Ac-Asp-Glu-Val-Asp-Cys(StBu)-Lys(DOTA(Gd))-CBT (DEVDCS-Gd-CBT) for apoptosis imaging in vivo. After Caspase-3 cleavage in apoptotic cells, DEVDCS-Gd-CBT underwent CBT-Cys click reaction to form a cyclic dimer, which self-assembled into Gd nanoparticles. With this probe, enhanced T1-weighted MR images of apoptosis were achieved at low magnetic fields in vitro, in cis-dichlorodiamineplatinum-induced apoptotic cells and in tail-amputation-simulated apoptotic zebrafish. We anticipate that the smart probe DEVDCS-Gd-CBT could be applied for T1-weighted MRI of apoptosis-related diseases in the clinic in the future.


Assuntos
Gadolínio , Nanopartículas , Animais , Caspase 3 , Peixe-Zebra , Imageamento por Ressonância Magnética/métodos , Apoptose , Meios de Contraste
11.
Yi Chuan ; 45(5): 447-458, 2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37194591

RESUMO

Neuregulin 4 (NRG4) is an important adipocytokine, which plays crucial roles in maintaining energy balance, regulating glucose and lipid metabolism, and preventing non-alcoholic fatty liver disease in mammals. At present, the genomic organization, transcript and protein isoforms of human NRG4 gene have been fully explored. Previous studies in our laboratory have shown that the NRG4 gene is expressed in chicken adipose tissue, but the chicken NRG4 (cNRG4) genomic structure, transcript and protein isoforms are still unknown. To this end, in this study, the genomic and transcriptional structure of the cNRG4 gene were systematically investigated using rapid amplification of cDNA ends (RACE) and reverse transcription-polymerase chain reaction (RT-PCR). The results showed that the coding region (CDS) of the cNRG4 gene was small, but it had a very complex transcriptional structure characterized by multiple transcription start sites, alternative splicing, intron retention, cryptic exons, and alternative polyadenylation, thus leading to production of four 5?UTR isoforms (cNRG4 A, cNRG4 B, cNRG4 C, and cNRG4 D) and six 3?UTR isoforms (cNRG4 a, cNRG4 b, cNRG4 c, cNRG4 d, cNRG4 e, and cNRG4 f) of the cNRG4 gene. The cNRG4 gene spanned 21,969 bp of genomic DNA (Chr.10:3,490,314~3,512,282) and consisted of 11 exons and 10 introns. Compared with the cNRG4 gene mRNA sequence (NM_001030544.4), two novel exons and one cryptic exon of the cNRG4 gene were identified in this study. Bioinformatics analysis, RT-PCR, cloning and sequencing analysis showed that the cNRG4 gene could encode three protein isoforms (cNRG4-1, cNRG4-2 and cNRG4-3). This study lays a foundation for further research on the function and regulation of the cNRG4 gene.


Assuntos
Processamento Alternativo , Galinhas , Animais , Processamento Alternativo/genética , Sequência de Bases , Galinhas/genética , DNA Complementar/genética , Genômica , Íntrons/genética , Neurregulinas/genética , Isoformas de Proteínas/genética
12.
PLoS Pathog ; 19(4): e1011341, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37083840

RESUMO

Infecting a wide range of hosts, members of Reovirales (formerly Reoviridae) consist of a genome with different numbers of segmented double stranded RNAs (dsRNA) encapsulated by a proteinaceous shell and carry out genome replication and transcription inside the virion. Several cryo-electron microscopy (cryo-EM) structures of reoviruses with 9, 10 or 11 segmented dsRNA genomes have revealed insights into genome arrangement and transcription. However, the structure and genome arrangement of 12-segmented Reovirales members remain poorly understood. Using cryo-EM, we determined the structure of mud crab reovirus (MCRV), a 12-segmented dsRNA virus that is a putative member of Reovirales in the non-turreted Sedoreoviridae family, to near-atomic resolutions with icosahedral symmetry (3.1 Å) and without imposing icosahedral symmetry (3.4 Å). These structures revealed the organization of the major capsid proteins in two layers: an outer T = 13 layer consisting of VP12 trimers and unique VP11 clamps, and an inner T = 1 layer consisting of VP3 dimers. Additionally, ten RNA dependent RNA polymerases (RdRp) were well resolved just below the VP3 layer but were offset from the 5-fold axes and arranged with D5 symmetry, which has not previously been seen in other members of Reovirales. The N-termini of VP3 were shown to adopt four unique conformations; two of which anchor the RdRps, while the other two conformations are likely involved in genome organization and capsid stability. Taken together, these structures provide a new level of understanding for capsid stabilization and genome organization of segmented dsRNA viruses.


Assuntos
Orthoreovirus , Vírus de RNA , Reoviridae , Proteínas do Capsídeo/genética , Capsídeo , Microscopia Crioeletrônica , Reoviridae/genética
13.
Zhongguo Dang Dai Er Ke Za Zhi ; 25(4): 339-343, 2023 Apr 15.
Artigo em Chinês | MEDLINE | ID: mdl-37073836

RESUMO

OBJECTIVES: To investigate the positive rate of enterovirus (EV) nucleic acid in throat swabs of term late neonates hospitalized during the coronavirus disease 2019 (COVID-19) epidemic and the clinical characteristics of the neonates. METHODS: A single-center cross-sectional study was performed on 611 term late infants who were hospitalized in the neonatal center from October 2020 to September 2021. Throat swabs were collected on admission for coxsackie A16 virus/EV71/EV universal nucleic acid testing. According to the results of EV nucleic acid test, the infants were divided into a positive EV nucleic acid group (8 infants) and a negative EV nucleic acid group (603 infants). Clinical features were compared between the two groups. RESULTS: Among the 611 neonates, 8 tested positive for EV nucleic acid, with a positive rate of 13.1‰, among whom 7 were admitted from May to October. There was a significant difference in the proportion of infants contacting family members with respiratory infection symptoms before disease onset between the positive and negative EV nucleic acid groups (75.0% vs 10.9%, P<0.001). There were no significant differences between the two groups in demographic data, clinical symptoms, and laboratory test results (P>0.05). CONCLUSIONS: There is a certain proportion of term late infants testing positive for EV nucleic acid in throat swabs during the COVID-19 epidemic, but the proportion is low. The clinical manifestations and laboratory test results of these infants are non-specific. Transmission among family members might be an important cause of neonatal EV infection.


Assuntos
COVID-19 , Infecções por Enterovirus , Enterovirus , Ácidos Nucleicos , Lactente , Recém-Nascido , Humanos , COVID-19/diagnóstico , Estudos Transversais , Faringe
14.
Opt Express ; 31(5): 8110-8119, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36859927

RESUMO

In this work, a simple dielectric metasurface hologram is proposed and designed by combining the electromagnetic vector analysis method and the immune algorithm, which can realize the holographic display of dual wavelength orthogonal-linear polarization light in visible light band, solve the problem of low efficiency of the traditional design method of metasurface hologram, and effectively improve the diffraction efficiency of metasurface hologram. The titanium dioxide metasurface nanorod based on rectangular structure is optimized and designed. When the x-linear polarized light with wavelength of 532 nm and y-linear polarized light with wavelength of 633 nm are incident on the metasurface respectively, different display output images with low cross-talk can be obtained on the same observation plane, and the transmission efficiencies of x-linear and y-linear polarized light are as high as 68.2% and 74.6% respectively in simulation. Then the metasurface is fabricated by Atomic Layer Deposition method. The experimental results are consistent with the design results, which proves that the metasurface hologram designed by this method can completely realize the feasibility of wavelength and polarization multiplexing holographic display, and has potential application value in holographic display, optical encryption, anti-counterfeiting, data storage and other fields.

15.
Adv Healthc Mater ; 12(18): e2203283, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36880480

RESUMO

Staphylococcus aureus (S. aureus) remains a leading cause of bacterial infections. However, eradication of S. aureus infections with common antibiotics is increasingly difficult due to outbreaks of drug resistance. Therefore, new antibiotic classes and antibacterial strategies are urgently in demand. Herein, it is shown that an adamantane-peptide conjugate, upon dephosphorylation by alkaline phosphatase (ALP) constitutively expressed on S. aureus, generates fibrous assemblies in situ to combat S. aureus infection. By attaching adamantane to a phosphorylated tetrapeptide Nap-Phe-Phe-Lys-Tyr(H2 PO3 )-OH, the rationally designed adamantane-peptide conjugate Nap-Phe-Phe-Lys(Ada)-Tyr(H2 PO3 )-OH (Nap-FYp-Ada) is obtained. Upon bacterial ALP activation, Nap-FYp-Ada is dephosphorylated and self-assembles into nanofibers on the surface of S. aureus. As revealed by cell assays, the assemblies of adamantane-peptide conjugates interact with cell lipid membrane and thereby disrupt membrane integrity to kill S. aureus. Animal experiments further demonstrate the excellent potential of Nap-FYp-Ada in the treatment of S. aureus infection in vivo. This work provides an alternative approach to design antimicrobial agents.


Assuntos
Anti-Infecciosos , Infecções Estafilocócicas , Animais , Staphylococcus aureus/metabolismo , Peptídeos/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Antibacterianos/farmacologia , Fosfatase Alcalina/metabolismo , Testes de Sensibilidade Microbiana
16.
Chaos ; 33(1): 013110, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36725628

RESUMO

Social interactions have become more complicated and changeable under the influence of information technology revolution. We, thereby, propose a multi-layer activity-driven network with attractiveness considering the heterogeneity of activated individual edge numbers, which aims to explore the role of heterogeneous behaviors in the time-varying network. Specifically, three types of individual behaviors are introduced: (i) self-quarantine of infected individuals, (ii) safe social distancing between infected and susceptible individuals, and (iii) information spreading of aware individuals. Epidemic threshold is theoretically derived in terms of the microscopic Markov chain approach and the mean-field approach. The results demonstrate that performing self-quarantine and maintaining safe social distance can effectively raise the epidemic threshold and suppress the spread of diseases. Interestingly, individuals' activity and individuals' attractiveness have an equivalent effect on epidemic threshold under the same condition. In addition, a similar result can be obtained regardless of the activated individual edge numbers. The epidemic outbreak earlier in a situation of the stronger heterogeneity of activated individual edge numbers.


Assuntos
Epidemias , Humanos , Surtos de Doenças , Quarentena , Cadeias de Markov , Suscetibilidade a Doenças
17.
Biomimetics (Basel) ; 8(1)2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36810390

RESUMO

Inspired by rodents' ability to navigate freely in a given space, bionavigation systems provide alternatives to traditional probabilistic solutions. This paper proposed a bionic path planning method based on RatSLAM to provide a novel viewpoint for robots to make a more flexible and intelligent navigation scheme. A neural network fusing historic episodic memory was proposed to improve the connectivity of the episodic cognitive map. It is biomimetically important to generate an episodic cognitive map and establish a one-to-one correspondence between the events generated by episodic memory and the visual template of RatSLAM. The episodic cognitive map can be improved by imitating the rodents' behavior of memory fusion to produce better path planning results. The experimental results of different scenarios illustrate that the proposed method identified the connectivity between way points, optimized the result of path planning, and improved the flexibility of the system.

18.
Polymers (Basel) ; 15(2)2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36679131

RESUMO

Conductive hydrogels with high electrical conductivity, ductility, and anti-dryness have promising applications in flexible wearable electronics. However, its potential applications in such a developing field are severely hampered by its extremely poor adaptability to cold or hot environmental conditions. In this research, an "organic solvent/water" composite conductive hydrogel is developed by introducing a binary organic solvent of EG/H2O into the system using a simple one-pot free radical polymerization method to create Ti3C2TX MXene nanosheet-reinforced polyvinyl alcohol/polyacrylamide covalently networked nanocomposite hydrogels (PAEM) with excellent flexibility and mechanical properties. The optimized PAEM contains 0.3 wt% MXene has excellent mechanical performance (tensile elongation of ~1033%) and an improved modulus of elasticity (0.14 MPa), a stable temperature tolerance from -50 to 40 °C, and a high gauge factor of 10.95 with a long storage period and response time of 110 ms. Additionally, it is worth noting that the elongation at break at -40 °C was maintained at around 50% of room temperature. This research will contribute to the development of flexible sensors for human-computer interaction, electronic skin, and human health monitoring.

19.
Sci Total Environ ; 866: 161384, 2023 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-36621475

RESUMO

Plantation forests are essential in driving global biogeochemical cycling and mitigating climate change. Biodiversity and environmental factors can shape multiple forest ecosystem functions simultaneously (i.e., multifunctionality). However, their effect on multifunctionality when pure plantations are converted into two-aged plantations remains underexplored. Therefore, we assessed above- and below-ground biodiversity and environmental factors and 11 ecosystem functions in different plantation types in subtropical China. The two-aged mixed plantations exhibited higher multifunctionality than did a pure plantation, primarily due to soil fungal diversity and secondarily due to tree diversity, based on the coefficient of variation for tree diameter at breast height (CVD) and community-weighted specific leaf area (CWMSLA). Further analysis revealed saprotrophy as the key soil fungal trophic mode in maintaining multifunctionality. Moreover, structural equation modeling confirmed that soil environmental factors, namely the soil water content and pH, had no direct association with multifunctionality, but were indirectly related to multifunctionality via elevated CVD and CWMSLA, respectively. Our results indicate that the tree and soil fungal diversity, as well as soil environmental factors, resulting from the conversion of pure plantations to two-aged mixed plantations, can enhance multifunctionality, and provide a better comprehensive understanding of the driving mechanisms of multifunctionality, leading to the sustainable management of subtropical plantation forest ecosystems.


Assuntos
Ecossistema , Florestas , Biodiversidade , Árvores , Solo/química , China
20.
Polym Bull (Berl) ; : 1-15, 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36530485

RESUMO

With N,N'-methylenebisacrylamide (MBA) and polyvinyl alcohol (PVA) as raw materials, a polymer (PVA-MBA) containing N-halamine precursor functional groups was obtained via grafting reaction between the active hydroxyl groups on PVA and α, ß-unsaturated functional groups of MBA under the catalysis of sodium carbonate in an aqueous solution. An acyclic N-halamine precursor-grafted PVA (MBA-PVA) film was formed by simply spreading PVA-MBA aqueous solution in a glass dish and drying it. An antimicrobial acyclic N-halamine-grafted PVA (PVA-MBA-Cl) film was achieved by spraying the diluted sodium hypochlorite solution onto the surface of PVA-MBA film. The performance test of PVA-MBA-Cl film under the optimal preparation conditions showed that the tensile performance and the hydrophobicity were improved, compared to the PVA film. The storage stability test indicated that the oxidative chlorine content Cl+ (atoms/cm2) of the as-prepared PVA-MBA-Cl film only reduced by 14.3% after storage for 9 weeks, showing that the antibacterial N-halamine functional groups in PVA-MBA-Cl film has excellent storage stability under room temperature. Antibacterial test showed that the PVA-MBA-Cl film had very strong antibacterial efficacies and could completely kill 1.28 × 106 CFU/mL S. aureus and 1.89 × 106 CFU/mL E. coli within 1 min. Therefore, PVA-MBA-Cl film will have more potential applications in food package.

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