Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Adv Mater ; : e2401738, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38771624

RESUMO

Metasurface holograms represent a common category of metasurface devices that utilize in-plane phase gradients to shape wavefronts, forming holographic images through the application of the generalized Snell's law (GSL). While conventional metasurfaces focus solely on phase gradients, metagratings, which incorporate higher-order wave diffraction, further expand the GSL's generality. Recent advances in certain acoustic metagratings demonstrate an updated GSL extension capable of reversing anomalous transmission and reflection, whose reversal is characterized by the parity of the number of wave propagation trips through the metagrating. However, the current extension of GSL remains limited to 1D metagratings, unable to access 2D holographic images in 3D spaces. Here, the GSL extension to 2D metagratings for manipulating waves within 3D spaces is investigated. Through this analysis, a series of acoustic metagrating holograms is experimentally demonstrated. These holographic images exhibit the unique ability to switch between transmission and reflection types independently. This study introduces an additional dimension to modern holography design and metasurface wavefront manipulation.

2.
Adv Sci (Weinh) ; : e2401046, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38666450

RESUMO

Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by excessive proliferation of rheumatoid arthritis synovial fibroblasts (RASFs) and accumulation of inflammatory cytokines. Exploring the suppression of RASFs and modulation of the RA microenvironment is considered a comprehensive strategy for RA. In this work, specifically activated nanoagents (MAHI NGs) based on the hypoxic and weakly acidic RA microenvironment are developed to achieve a second near-infrared fluorescence (NIR-II FL)/photoacoustic (PA) dual-model imaging-guided multi-treatment. Due to optimal size, the MAHI NGs passively accumulate in the diseased joint region and undergo rapid responsive degradation, precisely releasing functionalized components: endogenous melanin-nanoparticles (MNPs), hydrogen gas (H2), and indocyanine green (ICG). The released MNPs play a crucial role in ablating RASFs within the RA microenvironment through photothermal therapy (PTT) guided by accurate PA imaging. However, the regional hyperthermia generated by PTT may exacerbate reactive oxygen species (ROS) production and inflammatory response following cell lysis. Remarkably, under the acidic microenvironment, the controlled release of H2 exhibits precise synergistic antioxidant and anti-inflammatory effects with MNPs. Moreover, the ICG, the second near-infrared dye currently approved for clinical use, possesses excellent NIR-II FL imaging properties that facilitate the diagnosis of deep tissue diseases and provide the right time-point for PTT.

3.
J Environ Manage ; 354: 120337, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38417357

RESUMO

China, being a major agricultural nation, employs aerobic composting as an efficient approach to handle agricultural solid waste. Nevertheless, the composting process is often accompanied by greenhouse gas emissions, which are known contributors to global warming. Therefore, it is urgent to control the formation and emission of greenhouse gases from composting. This study provides a comprehensive analysis of the mechanisms underlying the production of nitrous oxide, methane, and carbon dioxide during the composting process of agricultural wastes. Additionally, it proposes an overview of the variables that affect greenhouse gas emissions, including the types of agricultural wastes (straw, livestock manure), the specifications for compost (pile size, aeration). The key factors of greenhouse gas emissions during composting process like physicochemical parameters, additives, and specific composting techniques (reuse of mature compost products, ultra-high-temperature composting, and electric-field-assisted composting) are summarized. Finally, it suggests directions and perspectives for future research. This study establishes a theoretical foundation for achieving carbon neutrality and promoting environmentally-friendly composting practices.


Assuntos
Compostagem , Gases de Efeito Estufa , Gases de Efeito Estufa/análise , Agricultura , Dióxido de Carbono/análise , Aquecimento Global , Metano/análise , Óxido Nitroso/análise , Esterco/análise , Solo
4.
J Hazard Mater ; 460: 132473, 2023 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-37683348

RESUMO

The extensive utilization of neonicotinoid insecticides (NNIs) in agricultural practices ultimately poses a significant threat to both the environment and human health. This work focuses on the efficient degradation and detoxification of the representative NNI, thiamethoxam (THX), and explores the underlying mechanism using a Co-Fe-Mn mixed spinel doped carbon composite catalyst activated persulfate. The findings demonstrate that the composite effectively degrades THX, achieving a degradation rate of 95% in 30 mins, while requiring only a fraction (one-sixteenth) of the oxidant dosage compared to pure carbon. The study aimed to examine the negative impact of reactive halogens on reactive oxygen species within a saline environment. The degradation byproducts were linked to the presence of two common electron-withdrawing groups, namely halogens and nitro in the THX molecule. It was hypothesized that the degradation process was primarily influenced by C-N bond breaking and hydroxylation occurring between the diazine oxide and 2-chlorothiazole rings. Consequently, dehalogenation and carbonylation processes facilitated the elimination of halogenated components and pharmacophores from the THX, leading to detoxification. In addition to the identified free radical pathway including SO4•-, •OH and O2•- contributed to THX degradation, the participation of non-radical pathways (1O2 and electron transfer) were also confirmed. The efficacy of detoxification was further validated through toxicity assessment, employing quantitative conformation relationship prediction and microbial culture utilizing Bacillus subtilis.


Assuntos
Inseticidas , Humanos , Tiametoxam , Carbono , Halogênios
5.
Bioresour Technol ; 366: 128224, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36328174

RESUMO

Carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) cycling functional genes and bacterial and fungal communities during composting with biochar and biogas residue amendments were studied. Correlations between microbial community structure, functional genes and physicochemical properties were investigated by network analysis and redundancy analysis. It was shown that the gene of acsA abundance accounted for about 50% of the C-related genes. Biogas residue significantly decreased the abundance of denitrification gene nirK. Biogas residues can better promote the diversity of bacteria and fungi during composting. Biochar significantly increased the abundance of Humicola. Redundancy analysis indicated that pile temperature, pH, EC were the main physicochemical factors affecting the microbial community. WSC and NO3--N have significant correlation with C, N, P, S functional genes. The research provides a theoretical basis for clarifying the metabolic characteristics of microbial communities during composting and for the application of biochar and biogas residues in composting.


Assuntos
Compostagem , Microbiota , Nitrogênio/metabolismo , Biocombustíveis , Fósforo , Carbono , Solo/química , Carvão Vegetal , Microbiota/genética , Bactérias/genética , Bactérias/metabolismo , Enxofre
6.
ACS Nano ; 16(11): 17998-18008, 2022 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-36136126

RESUMO

Conductive polymers have many advanced applications, but there is still an important target in developing a general and straightforward strategy for printable, mechanically stable, and durable organohydrogels with typical conducting polymers of, for example, polypyrrole, polyaniline, or poly(3,4-ethylenedioxythiophene). Here we report a protein crystallization-mediated self-strengthening strategy to fabricate printable conducting organohydrogels with the combination of rational photochemistry design. Such organohydrogels are one-step prepared via rapidly and orthogonally controllable photopolymerizations of pyrroles and gelatin protein in tens of seconds. As-prepared conducting organohydrogels are patterned and printed to complicated structures via shadow-mask lithography and 3D extrusion technology. The mild photocatalytic system gives the transition metal carbide/nitride (MXene) component high stability during the oxidative preparation process and storage. Controlling water evaporation promotes gelatin crystallization in the as-prepared organohydrogels that significantly self-strengthens their mechanical property and stability in a broad temperature range and durability against continuous friction treatment without introducing guest functional materials. Also, these organohydrogels have commercially electromagnetic shielding, thermal conducting properties, and temperature- and light-responsibility. To further demonstrate the merits of this simple strategy and as-prepared organohydrogels, prism arrays, as proofs-of-concept, are printed and applied to make wearable triboelectric nanogenerators. This self-strengthening process and 3D-printability can greatly improve their voltage, charge, and current output performances compared to the undried and flat samples.


Assuntos
Gelatina , Polímeros , Cristalização , Polímeros/química , Pirróis/química , Hidrogéis/química
7.
Sci Total Environ ; 822: 153483, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35093361

RESUMO

It has been confirmed that silicon (Si) fertilizer and humic acid (HA) could effectively decrease the heavy metals in soil. Nonetheless, the impact of these additives on soil aggregate characteristics was ignored. Therefore, the effects of Si fertilizer, HA, and their combinations on the physicochemical characteristics, availability of heavy metals (Cu, Cd, Pb, Zn), and fraction changes in soils and soil aggregates were investigated in this research. The results showed that Si fertilizer and HA significantly modified soil properties such as soil pH, electrical conductivity total organic carbon, water-soluble organic carbon, and nitrate­nitrogen. HA and Si-HA (SHA) supplementation significantly decreased the availability of Cu, Cd, Pd, and Zn. Besides, there was no significant difference in physicochemical properties between soil and soil aggregates. The availability of Cu, Cd, Pd, and Zn in soil aggregates could be significantly inhibited by the addition of HA and SHA, and the content in microaggregates was greater than that in macroaggregates. After the addition of the three additives, the main fractions of heavy metals in different particle sizes were changed and eventually transformed to the residue state. These results indicated that Si fertilizer, HA, and SHA were influential in physicochemical properties and metal availability in soil aggregates. Therefore, it is of great scientific significance to study the impact of heavy metal pollution on the ecological environment in different aggregates, which will provide reference data for future sustainable management of heavy-metal polluted soils.


Assuntos
Metais Pesados , Poluentes do Solo , China , Fertilizantes/análise , Substâncias Húmicas , Metais Pesados/análise , Silício , Solo/química , Poluentes do Solo/análise
8.
Environ Res ; 205: 112244, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34688645

RESUMO

Chemical fertilizer is gaining increasing attention and has been the center of much research which indicating complex beneficial and harmful effects. Chemical fertilizer might cause some environmental hazards to the biosphere, especially in the agricultural ecosystem. The application of silicon (Si) fertilizer in agriculture has been proved to be able to create good economic and environmental benefits. Si is the second most abundant earth crust element. Si fertilizer improves soil quality and alleviates biotic and abiotic crop stress. It is of great significance to understand the function of Si fertilizer in agricultural utilization and environmental remediation. This paper reviews the Si-based fertilizer in farmland use and summarizes prior research relevant with characterization, soil quality improvement, and pollution remediation effects. Its use in agriculture enhances plant silicon uptake, mediates plant salt and drought stress and remediates heavy metals such as Al, As, Cd, Cu, Zn and Cr. This article also summarizes the detoxification mechanism of silicon and its effects on plant physiological activity such as photosynthesis and transpiration. Fertilizer materials and crop fertilizer management were also considered. Foliar spraying is an effective method to improve crop growth and yield and reduce biotic or abiotic stress. Silicon nanoparticle material provides potential with great potential and prospects. More investigation and research are prospected to better understand how silicon impacts the environment and whether it is a beneficial additive.


Assuntos
Metais Pesados , Poluentes do Solo , Ecossistema , Metais Pesados/análise , Metais Pesados/toxicidade , Silício , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
9.
Bioresour Technol ; 345: 126489, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34871723

RESUMO

This experiment was carried out to explore the effects of biochar, biogas residue and their combination amendment on enzyme activities and their stoichiometry during agricultural waste composting. A comprehensive analysis of the variation in, and stoichiometric correlations between, ß-glucosidase (BG), N-acetylglucosaminidase (NAG), leucine aminopeptidase (LAP), and alkaline phosphatase (AKP) were determined. The results showed that biochar, biogas residue, and their combined addition significantly increased those enzyme activities. The potential C:P and N:P acquisition activities represented by ln(BG): ln(AKP) and ln(LAP + NAG): ln(AKP), were significantly decreased with biogas residue addition. BG, NAG and LAP were significantly negatively correlated with temperature, organic matter and water-soluble carbon. Redundancy analysis also showed that moisture and water-soluble carbon were significantly related to the variations of enzyme activities. Biochar and biogas residue changed the characteristics of the composting substrate, thus affecting the activity and stoichiometry of functional enzymes involved in C, N and P cycling.


Assuntos
Compostagem , Biocombustíveis , Carvão Vegetal , Nitrogênio/análise , Solo
10.
Sci Rep ; 6: 36664, 2016 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-27819357

RESUMO

Post-pollination processes can lead to nonrandom mating among compatible pollen donors. Moreover, morphological patterns of ovule development within linear fruits are reportedly nonrandom and depend on ovule position. However, little is known about the relationship between nonrandom mating and ovule position within linear fruit. Here, we combined controlled pollen competition experiments and paternity analyses on R. pseudoacacia to better understand nonrandom mating and its connection with ovule position. Molecular determination of siring success showed a significant departure from the expected ratio based on each kind of pollen mixture, suggesting a nonrandom mating. Outcrossed pollen grains, which were strongly favored, produced significantly more progeny than other pollen grains. Paternity analyses further revealed that the distribution of offspring produced by one specific pollen source was also nonrandom within linear fruit. The stylar end, which has a higher probability of maturation, produced a significantly higher number of outcrossed offspring than other offspring, suggesting a correlation between pollen source and ovule position. Our results suggested that a superior ovule position exists within the linear fruit in R. pseudoacacia, and the pollen that was strongly favored often preferentially occupies the ovules that were situated in a superior position, which ensured siring success and facilitated nonrandom mating.


Assuntos
Frutas/anatomia & histologia , Óvulo Vegetal/anatomia & histologia , Pólen/fisiologia , Robinia/fisiologia , Animais , Reprodução
11.
Tumour Biol ; 37(11): 14961-14967, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27651160

RESUMO

Homeobox C8 (HOXC8) has been implicated in cell growth, migration, and metastasis of various cancers, yet its role in osteosarcoma remains to be explored. In the present study, resected osteosarcoma specimens from 50 patients were enrolled to evaluate the expression of HOXC8 protein by immunohistochemistry (IHC). In vitro and in vivo assays were used to determine the effect of HOXC8 on cell growth, migration, and tumor growth. HOXC8 expression was observed in 31 (62.0 %) of the 50 primary tumors and significantly associated with poorly or un-differentiated specimens (P = 0.031) and larger tumor size (P = 0.049). Survival analysis demonstrated that HOXC8 is a candidate predictive factor in predicting patients' outcome and chemotherapeutic effect. HOXC8 knockdown led to inhibition of tumor cell proliferation and migration in vitro by inhibiting MMP-9 expression and tumor growth in vivo. Our results strongly suggest that HOXC8 is involved in the tumorigenesis of osteosarcoma and might serve as a novel predictor for patients' outcome.


Assuntos
Neoplasias Ósseas/patologia , Movimento Celular/genética , Proliferação de Células/genética , Proteínas de Homeodomínio/genética , Metaloproteinase 9 da Matriz/biossíntese , Osteossarcoma/patologia , Adolescente , Animais , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias , Interferência de RNA , RNA Interferente Pequeno , Transplante Heterólogo , Resultado do Tratamento
12.
BMC Evol Biol ; 14(1): 53, 2014 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-24655746

RESUMO

BACKGROUND: Pollen donor compositions differ during the early stages of reproduction due to various selection mechanisms. In addition, ovules linearly ordered within a fruit have different probabilities of reaching maturity. Few attempts, however, have been made to directly examine the magnitude and timing of selection, as well as the mechanisms during early life stages and within fruit. Robinia pseudoacacia, which contains linear fruit and non-random ovule maturation and abortion patterns, has been used to study the viability of selection within fruit and during the early stages of reproduction. To examine changes in the pollen donor composition during the early stages of reproduction and of progeny originating from different positions within fruit, paternity analyses were performed for three early life stages (aborted seeds, mature seeds and seedlings) in the insect-pollinated tree R. pseudoacacia. RESULTS: Selection resulted in an overall decrease in the level of surviving selfed progeny at each life stage. The greatest change was observed between the aborted seed stage and mature seed stage, indicative of inbreeding depression (the reduced fitness of a given population that occurs when related individual breeding was responsible for early selection). A selective advantage was detected among paternal trees. Within fruits, the distal ends showed higher outcrossing rates than the basal ends, indicative of selection based on the order of seeds within the fruit. CONCLUSIONS: Our results suggest that selection exists both within linear fruit and during the early stages of reproduction, and that this selection can affect male reproductive success during the early life stages. This indicates that tree species with mixed-mating systems may have evolved pollen selection mechanisms to increase the fitness of progeny and adjust the population genetic composition. The early selection that we detected suggests that inbreeding depression caused the high abortion rate and low seed set in R. pseudoacacia.


Assuntos
Robinia/crescimento & desenvolvimento , Robinia/genética , Cruzamento , Frutas/genética , Fluxo Gênico , Variação Genética , Pólen/genética , Polinização , Reprodução , Robinia/fisiologia , Sementes/genética , Árvores/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...