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1.
J Environ Sci (China) ; 148: 702-713, 2025 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-39095202

RESUMO

Chinese diesel trucks are the main contributors to NOx and particulate matter (PM) vehicle emissions. An increase in diesel trucks could aggravate air pollution and damage human health. The Chinese government has recently implemented a series of emission control technologies and measures for air quality improvement. This paper summarizes recent control technologies and measures for diesel truck emissions in China and introduces the comprehensive application of control technologies and measures in Beijing-Tianjin-Hebei and surrounding regions. Remote online monitoring technology has been adopted according to the China VI standard for heavy-duty diesel trucks, and control measures such as transportation structure adjustment and heavy pollution enterprise classification control continue to support the battle action plan for pollution control. Perspectives and suggestions are provided for promoting pollution control and supervision of diesel truck emissions: adhere to the concept of overall management and control, vigorously promote the application of systematic and technological means in emission monitoring, continuously facilitate cargo transportation structure adjustment and promote new energy freight vehicles. This paper aims to accelerate the implementation of control technologies and measures throughout China. China is endeavouring to control diesel truck exhaust pollution. China is willing to cooperate with the world to protect the global ecological environment.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Monitoramento Ambiental , Material Particulado , Emissões de Veículos , Emissões de Veículos/análise , China , Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental/métodos , Material Particulado/análise , Veículos Automotores
2.
Eur J Med Chem ; 280: 116945, 2024 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-39388907

RESUMO

TLR4 signaling is instrumental in orchestrating multiple aspects of innate immunity. Developing small molecule inhibitors targeting the TLR4 pathway holds potential therapeutic promise for TLR4-related disorders. Herein, an artificial intelligence (AI)-powered next-generation screening approach, employing HelixVS and HelixDock, was utilized to focus on the TLR4-TLR4∗ (a second copy of TLR4) homodimerization surface, leading to the identification of a potent pyrazolo[1,5-a]pyrimidine derivative, designated as compound 1. An extensive structure-activity relationship (SAR) exploration culminated in the discovery of the lead compound TH023, which effectively blocked the LPS-stimulated NF-κB activation and nitric oxide overproduction in HEK-Blue hTLR4 and RAW264.7 cells, with IC50 values of 0.354 and 1.61 µM, respectively. Molecular dynamic (MD) simulations indicated that TH023 stabilized TLR4-MD-2 and disrupted its association with TLR4∗. Moreover, TH023 alleviated the lung injury and decreased pro-inflammatory cytokine levels in LPS-induced septic mice. These findings not only illuminated the strategic advantage of HelixDock in advancing the frontiers of AI-driven drug discovery, but also provided valuable structural insights for the rational design of TLR4-TLR4∗ protein-protein interaction (PPI) inhibitors based on the pyrazolo[1,5-a]pyrimidine scaffold. Overall, this study validated a new strategy for TLR4 signaling regulation by targeting its dimerization, thereby underscoring the therapeutic promise of TH023 in treating TLR4-mediated inflammatory diseases.

3.
Nat Chem Biol ; 2024 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-39394267

RESUMO

The DNA damage repair regulatory protein RNF168, a monomeric RING-type E3 ligase, has a crucial role in regulating cell fate and DNA repair by specific and efficient ubiquitination of the adjacent K13 and K15 (K13/15) sites at the H2A N-terminal tail. However, understanding how RNF168 coordinates with its cognate E2 enzyme UbcH5c to site-specifically ubiquitinate H2A K13/15 has long been hampered by the lack of high-resolution structures of RNF168 and UbcH5c~Ub (ubiquitin) in complex with nucleosomes. Here we developed chemical strategies and determined the cryo-electron microscopy structures of the RNF168-UbcH5c~Ub-nucleosome complex captured in transient H2A K13/15 monoubiquitination and adjacent dual monoubiquitination reactions, providing a 'helix-anchoring' mode for monomeric E3 ligase RNF168 on nucleosome in contrast to the 'compass-binding' mode of dimeric E3 ligases. Our work not only provides structural snapshots of H2A K13/15 site-specific monoubiquitination and adjacent dual monoubiquitination but also offers a near-atomic-resolution structural framework for understanding pathogenic amino acid substitutions and physiological modifications of RNF168.

4.
Mol Med Rep ; 30(6)2024 12.
Artigo em Inglês | MEDLINE | ID: mdl-39370810

RESUMO

Myocardial fibrosis (MF) significantly compromises cardiovascular health by affecting cardiac function through excessive collagen deposition. This impairs myocardial contraction and relaxation and leads to severe complications and increased mortality. The present study employed network pharmacology and in vitro assays to investigate the bioactive compounds of Rhodiola rosea and their targets. Using databases such as HERB, the Encyclopedia of Traditional Chinese Medicine, Pubchem, OMIM and GeneCards, the present study identified effective components and MF­related targets. Network analysis was conducted with Cytoscape to develop a Drug­Ingredient­Target­Disease network and the STRING database was utilized to construct a protein­protein interaction network. Key nodes were analyzed for pathway enrichment using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Molecular interactions were further explored through molecular docking techniques. The bioactivity of salidroside (SAL), the principal component of Rhodiola rosea, against MF was experimentally validated in H9c2 cardiomyocytes treated with angiotensin II and assessed for cell viability, protein expression and oxidative stress markers. Network pharmacology identified 25 active ingredients and 372 targets in Rhodiola rosea, linking SAL with pathways such as MAPK, EGFR, advanced glycosylation end products­advanced glycosylation end products receptor and Forkhead box O. SAL showed significant interactions with core targets such as albumin, IL6, AKT serine/threonine kinase 1, MMP9 and caspase­3. In vitro, SAL mitigated AngII­induced increases in collagen I and alpha smooth muscle actin protein levels and oxidative stress markers, demonstrating dose­dependent effectiveness in reversing MF. SAL from Rhodiola rosea exhibited potent anti­oxidative properties that mitigated MF by modulating multiple molecular targets and signaling pathways. The present study underscored the therapeutic potential of SAL in treating oxidative stress­related cardiovascular diseases.


Assuntos
Fibrose , Simulação de Acoplamento Molecular , Miócitos Cardíacos , Farmacologia em Rede , Estresse Oxidativo , Rhodiola , Rhodiola/química , Animais , Ratos , Estresse Oxidativo/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Fibrose/tratamento farmacológico , Antioxidantes/farmacologia , Antioxidantes/química , Linhagem Celular , Mapas de Interação de Proteínas/efeitos dos fármacos , Glucosídeos/farmacologia , Glucosídeos/química , Miocárdio/metabolismo , Miocárdio/patologia , Sobrevivência Celular/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Humanos , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Fenóis
5.
ACS Nano ; 18(41): 28026-28037, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39350442

RESUMO

Translating high-performance organic solar cell (OSC) materials from spin-coating to scalable processing is imperative for advancing organic photovoltaics. For bridging the gap between laboratory research and industrialization, it is essential to understand the structural formation dynamics within the photoactive layer during printing processes. In this study, two typical printing-compatible solvents in the doctor-blading process are employed to explore the intricate mechanisms governing the thin-film formation in the state-of-the-art photovoltaic system PM6:L8-BO. Our findings highlight the synergistic influence of both the donor polymer PM6 and the solvent with a high boiling point on the structural dynamics of L8-BO within the photoactive layer, significantly influencing its morphological properties. The optimized processing strategy effectively suppresses the excessive aggregation of L8-BO during the slow drying process in doctor-blading, enhancing thin-film crystallization with preferential molecular orientation. These improvements facilitate more efficient charge transport, suppress thin-film defects and charge recombination, and finally enhance the upscaling potential. Consequently, the optimized PM6:L8-BO OSCs demonstrate power conversion efficiencies of 18.42% in small-area devices (0.064 cm2) and 16.02% in modules (11.70 cm2), respectively. Overall, this research provides valuable insights into the interplay among thin-film formation kinetics, structure dynamics, and device performance in scalable processing.

6.
Adv Mater ; : e2406088, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39402768

RESUMO

With freshwater resources becoming increasingly scarce, the photocatalytic seawater splitting for hydrogen production has garnered widespread attention. In this study, a novel photocatalyst consisting of a Cu core coated is introduced with N-doped C and decorated with single Co atoms (Co-NC@Cu) for solar to hydrogen production from seawater. This catalyst, without using noble metals or sacrificial agents, demonstrates superior hydrogen production effficiency of 9080 µmolg-1h-1, i.e., 4.78% solar-to-hydrogen conversion efficiency, and exceptional long-term stability, operating over 340 h continuously. The superior performance is attributed to several key factors. First, the focus-light induced photothermal effect enhances redox reaction capabilities, while the salt-ions enabled charge polarization around catalyst surfaces extends charge carrier lifetime. Furthermore, the Co─NC@Cu exhibits excellent broad light absorption, promoting photoexcited charge production. Theoretical calculations reveal that Co─NC acts as the active site, showing low energy barriers for reduction reactions. Additionally, the formation of a strong surface electric field from the localized surface plasmon resonance (LSPR) of Cu nanoparticles further reduces energy barriers for redox reactions, improving seawater splitting activity. This work provides valuable insights into intergrating the reaction environment, broad solar absorption, LSPR, and active single atoms into a core-shell photocatalyst design for efficient and robust solar-driven seawater splitting.

7.
STAR Protoc ; 5(4): 103314, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39298323

RESUMO

4-Octyl itaconate (4-OI), a derivative of itaconate, inhibits inflammation by alkylating its target proteins. Here, we present a click-chemistry-based protocol for detecting 4-OI-alkylated proteins in mouse primary bone-marrow-derived macrophages (BMDMs) by using an itaconate-alkyne (ITalk) probe. We describe steps for culturing and treating BMDMs and details on using click chemistry in the cell lysate. We also detail procedures for detecting alkylated proteins by western blot. For complete details on the use and execution of this protocol, please refer to Su et al.1.

8.
Chem Mater ; 36(18): 8834-8845, 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39347471

RESUMO

We report a synthesis of WSe2 nanocrystals in which the number of layers is controlled by varying the precursor concentration. By altering the ratios and concentrations of W(CO)6 and Ph2Se2 in trioctylphosphine oxide, we show that high [Se] and large Se/W ratios lead to an increased number of layers per nanocrystal. As the number of layers per nanocrystal is increased, the nanocrystal ensembles show less phase-conversion from the metastable 2M phase to the thermodynamically favored 2H phase. Density functional theory calculations indicate that the interlayer binding energy increases with the number of layers, indicating that the stronger interlayer interactions in multilayered nanocrystals may increase the energy barrier to phase-conversion. The results presented herein provide insights for directing phase-conversion in solution-phase syntheses of transition metal dichalcogenides.

9.
Dalton Trans ; 53(38): 16066-16075, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39295573

RESUMO

The precise design of active sites and light absorbers is essential for developing highly efficient photocatalysts for CO2 reduction. Core-shell heterostructures constructed based on large-sized plasmonic Bi metals are ideal candidates because of the utilization of full-spectrum light and effective charge separation. However, the mechanism of selectivity modulation of large-sized Bi@semiconductor photocatalysts has yet to be explored in depth. Herein, a plasmonic Bi@Bi2O2CO3 core-shell heterostructure was successfully synthesized via a facile solvothermal treatment in deep eutectic solvents, demonstrating highly efficient photocatalytic CO2 reduction. This structure features a sizeable Bi sphere with a thin, epitaxially grown Bi2O2CO3 shell, which allows for the utilization of the entire light spectrum. Additionally, the oxygen vacancies in the Bi2O2CO3 shell can rapidly trap electrons transferred from the Bi core via Bi-O-Bi bonds, thereby forming abundant electron-rich interfaces that serve as the active sites for activating reactant molecules and facilitating the reaction.

10.
Nucleic Acids Res ; 52(18): 11336-11348, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39217465

RESUMO

Recently, a novel two-gene bacterial defense system against phages, encoding a SIR2 NADase and a HerA ATPase/helicase, has been identified. However, the molecular mechanism of the bacterial SIR2-HerA immune system remains unclear. Here, we determine the cryo-EM structures of SIR2, HerA and their complex from Paenibacillus sp. 453MF in different functional states. The SIR2 proteins oligomerize into a dodecameric ring-shaped structure consisting of two layers of interlocked hexamers, in which each subunit exhibits an auto-inhibited conformation. Distinct from the canonical AAA+ proteins, HerA hexamer alone in this antiphage system adopts a split spiral arrangement, which is stabilized by a unique C-terminal extension. SIR2 and HerA proteins assemble into a ∼1.1 MDa torch-shaped complex to fight against phage infection. Importantly, disruption of the interactions between SIR2 and HerA largely abolishes the antiphage activity. Interestingly, binding alters the oligomer state of SIR2, switching from a dodecamer to a tetradecamer state. The formation of the SIR2-HerA binary complex activates NADase and nuclease activities in SIR2 and ATPase and helicase activities in HerA. Together, our study not only provides a structural basis for the functional communications between SIR2 and HerA proteins, but also unravels a novel concerted antiviral mechanism through NAD+ degradation, ATP hydrolysis, and DNA cleavage.


Assuntos
Microscopia Crioeletrônica , Modelos Moleculares , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Bacteriófagos/genética , Multimerização Proteica , Ligação Proteica , Sirtuína 2/metabolismo , Sirtuína 2/química , Sirtuína 2/genética , DNA Helicases/metabolismo , DNA Helicases/química , DNA Helicases/genética , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/química , Adenosina Trifosfatases/genética , Conformação Proteica
11.
EMBO J ; 43(20): 4656-4667, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39251884

RESUMO

The Cas3 nuclease is utilized by canonical type I CRISPR-Cas systems for processive target DNA degradation, while a newly identified type I-F CRISPR variant employs an HNH nuclease domain from the natural fusion Cas8-HNH protein for precise target cleavage both in vitro and in human cells. Here, we report multiple cryo-electron microscopy structures of the type I-F Cas8-HNH system at different functional states. The Cas8-HNH Cascade complex adopts an overall G-shaped architecture, with the HNH domain occupying the C-terminal helical bundle domain (HB) of the Cas8 protein in canonical type I systems. The Linker region connecting Cas8-NTD and HNH domains adopts a rigid conformation and interacts with the Cas7.6 subunit, enabling the HNH domain to be in a functional position. The full R-loop formation displaces the HNH domain away from the Cas6 subunit, thus activating the target DNA cleavage. Importantly, our results demonstrate that precise target cleavage is dictated by a C-terminal helix of the HNH domain. Together, our work not only delineates the structural basis for target recognition and activation of the type I-F Cas8-HNH system, but also guides further developments leveraging this system for precise DNA editing.


Assuntos
Sistemas CRISPR-Cas , Microscopia Crioeletrônica , Proteínas Associadas a CRISPR/química , Proteínas Associadas a CRISPR/metabolismo , Proteínas Associadas a CRISPR/genética , Domínios Proteicos , Modelos Moleculares , Humanos , Conformação Proteica
12.
Chem Biol Interact ; 403: 111246, 2024 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-39278459

RESUMO

Darolutamide is a potent second-generation, selective nonsteroidal androgen receptor inhibitor (ARI), which has been approved by the US Food and Drug Administration (FDA) in treating castrate-resistant, non-metastatic prostate cancer (nmCRPC). Whether darolutamide affects the activity of UDP-glucuronosyltransferases (UGTs) is unknown. The purpose of the present study is to evaluate the inhibitory effect of darolutamide on recombinant human UGTs and pooled human liver microsomes (HLMs), and explore the potential for drug-drug interactions (DDIs) mediated by darolutamide through UGTs inhibition. The product formation rate of UGTs substrates with or without darolutamide was determined by HPLC or UPLC-MS/MS to estimate the inhibitory effect and inhibition modes of darolutamide on UGTs were evaluated by using the inhibition kinetics experiments. The results showed that 100 µM darolutamide exhibited inhibitory effects on most of the 12 UGTs tested. Inhibition kinetic studies of the enzyme revealed that darolutamide noncompetitively inhibited UGT1A1 and competitively inhibited UGT1A7 and 2B15, with the Ki of 14.75 ± 0.78 µM, 14.05 ± 0.42 µM, and 6.60 ± 0.08 µM, respectively. In particular, it also potently inhibited SN-38, the active metabolite of irinotecan, glucuronidation in HLMs with an IC50 value of 3.84 ± 0.46 µM. In addition, the in vitro-in vivo extrapolation (IVIVE) method was used to quantitatively predict the risk of darolutamide-mediated DDI via inhibiting UGTs. The prediction results showed that darolutamide may increase the risk of DDIs when administered in combination with substrates of UGT1A1, UGT1A7, or UGT2B15. Therefore, the combined administration of darolutamide and drugs metabolized by the above UGTs should be used with caution to avoid the occurrence of potential DDIs.

13.
Medicine (Baltimore) ; 103(37): e39566, 2024 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-39287275

RESUMO

BACKGROUND: Immunothrombosis is a physiological process that constitutes an intravascular innate immune response. Abnormal immunothrombosis can lead to thrombotic disorders. With the outbreak of COVID-19, there is increasing attention to the mechanisms of immunothrombosis and its critical role in thrombotic events, and a growing number of relevant research papers are emerging. This article employs bibliometrics to discuss the current status, hotspots, and trends in research of this field. METHODS: Research papers relevant to immunothrombosis published from January 1, 2003, to May 29, 2023, were collected from the Web of Science Core Collection database. VOSviewer and the R package "Bibliometrix" were employed to analyze publication metrics, including the number of publications, authors, countries, institutions, journals, and keywords. The analysis generated visual results, and trends in research topics and hotspots were examined. RESULTS: A total of 495 target papers were identified, originating from 58 countries and involving 3287 authors from 1011 research institutions. Eighty high-frequency keywords were classified into 5 clusters. The current key research topics in the field of immunothrombosis include platelets, inflammation, neutrophil extracellular traps, Von Willebrand factor, and the complement system. Research hotspots focus on the mechanisms and manifestations of immunothrombosis in COVID-19, as well as the discovery of novel treatment strategies targeting immunothrombosis in cardiovascular and cerebrovascular diseases. CONCLUSION: Bibliometric analysis summarizes the main achievements and development trends in research on immunothrombosis, offering readers a comprehensive understanding of the field and guiding future research directions.


Assuntos
Bibliometria , COVID-19 , Trombose , Humanos , COVID-19/imunologia , Trombose/imunologia , SARS-CoV-2/imunologia , Imunidade Inata , Plaquetas/imunologia
14.
Cell Chem Biol ; 31(9): 1566-1567, 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39303696

RESUMO

In early October, the Nobel Prizes will honor groundbreaking discoveries. After the anticipated recognition of Katalin Karikó and Drew Weissman in 2023 for the development of RNA modifications that enabled the SARS-CoV-2 mRNA vaccine, we eagerly consider the next topics to be awarded. In the September 30th anniversary special issue of Cell Chemical Biology, we ask researchers from a range of backgrounds, what topic do you think deserves the next Nobel Prize in chemistry or in physiology or medicine, and why?


Assuntos
Prêmio Nobel , Humanos , Química/história , SARS-CoV-2 , COVID-19/virologia , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/química
15.
Environ Int ; 190: 108945, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39151268

RESUMO

Vehicle exhaust is one of the major organic sources in urban areas. Old taxis equipped with failed three-way catalysts (TWCs) have been regarded as "super emitters". Compressed natural gas (CNG) is a regular substitution fuel for gasoline in taxis. The relative effect of fuel substitution and TWC failure has not been thoroughly investigated. In this work, vehicle exhausts from gasoline and CNG taxis with optimally functioning and malfunctioning TWCs are sampled by Tenax TA tubes and then analyzed by a comprehensive two-dimensional gas chromatography-mass spectrometer (GC×GC-MS). A total of 216 organics are quantified, including 80 volatile organic compounds (VOCs) and 132 intermediate volatility organic compounds (IVOCs). Failure of TWC introduces super emitters with 30 - 70 times emission factors (EFs), 60 - 112 times ozone formation potentials (OFPs), and 34 - 92 times secondary organic aerosols (SOAs) more than normal vehicles. Specifically, for the taxi with failed TWC, the total organic EF of CNG is 16 times that of gasoline, indicating that the failure of TWC exceeds the emission reduction achieved by CNG-gasoline substitution. A significant but unbalanced reduction of ozone and SOA is observed after TWC, whereas a notable "enrichment" in IVOCs was observed. Naphthalene is a typical IVOC component strongly associated with CNG-gasoline substitution and TWC failure, which is lacking in current VOC measurement. We especially emphasize that there is an urgent need to scrap vehicles with failed TWCs in order to significantly reduce air pollution.


Assuntos
Poluentes Atmosféricos , Monitoramento Ambiental , Gasolina , Gás Natural , Emissões de Veículos , Compostos Orgânicos Voláteis , Emissões de Veículos/análise , Poluentes Atmosféricos/análise , Compostos Orgânicos Voláteis/análise , Gasolina/análise , Monitoramento Ambiental/métodos , Gás Natural/análise , Catálise , Cromatografia Gasosa-Espectrometria de Massas , Ozônio/química , Ozônio/análise , Poluição do Ar/prevenção & controle , Aerossóis/análise
16.
J Am Chem Soc ; 146(34): 24033-24041, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39146528

RESUMO

Palladium (Pd)-based single-atom catalysts (SACs) have shown outstanding selectivity for semihydrogenation of alkynes, but most Pd single sites coordinated with highly electronegative atoms (such as N, O, and S) of supports will result in a decrease in the electron density of Pd sites, thereby weakening the adsorption of reactants and reducing catalytic performance. Constructing a rich outer-shell electron environment of Pd single-atom sites by changing the coordination structure offers a novel opportunity to enhance the catalytic efficiency with excellent alkene selectivity. Therefore, in this work, we first propose the in situ preparation of isolated Pd sites encapsulated within Al/Si-rich ZSM-5 structure using the one-pot seed-assisted growth method. Pd1@ZSM-5 features Pd-O-Al/Si bonds, which can boost the domination of d-electron near the Fermi level, thereby promoting the adsorption of substrates on Pd sites and reducing the energy barrier for the semihydrogenation of alkynes. In semihydrogenation of phenylacetylene, Pd1@ZSM-5 catalyst performs the highest turnover frequency (TOF) value of 33582 molC═C/molPd/h with 96% selectivity of styrene among the reported heterogeneous catalysts and nearly 17-fold higher than that of the commercial Lindlar catalyst (1992 molC═C/molPd/h). This remarkable catalytic performance can be retained even after 6 cycles of usage. Particularly, the zeolitic confinement structure of Pd1@ZSM-5 enables precise shape-selective catalysis for alkyne reactants with a size less than 4.3 Å.

17.
Sci Total Environ ; 950: 175325, 2024 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-39117229

RESUMO

Silage is an excellent method of feed preservation; however, carbon dioxide, methane and nitrous oxide produced during fermentation are significant sources of agricultural greenhouse gases. Therefore, determining a specific production method is crucial for reducing global warming. The effects of four temperatures (10 °C, 20 °C, 30 °C, and 40 °C) on silage quality, greenhouse gas yield and microbial community composition of forage sorghum were investigated. At 20 °C and 30 °C, the silage has a lower pH value and a higher lactic acid content, resulting in higher silage quality and higher total gas production. In the first five days of ensiling, there was a significant increase in the production of carbon dioxide, methane, and nitrous oxide. After that, the output remained relatively stable, and their production at 20 °C and 30 °C was significantly higher than that at 10 °C and 40 °C. Firmicutes and Proteobacteria were the predominant silage microorganisms at the phylum level. Under the treatment of 20 °C, 30 °C, and 40 °C, Lactobacillus had already dominated on the second day of silage. However, low temperatures under 10 °C slowed down the microbial community succession, allowing, bad microorganisms such as Chryseobacterium, Pantoea and Pseudomonas dominate the fermentation, in the early stage of ensiling, which also resulted in the highest bacterial network complexity. According to random forest and structural equation model analysis, the production of carbon dioxide, methane and nitrous oxide is mainly affected by microorganisms such as Lactobacillus, Klebsiella and Enterobacter, and temperature influences the activity of these microorganisms to mediate gas production in silage. This study helps reveal the relationship between temperature, microbial community and greenhouse gas production during silage fermentation, providing a reference for clean silage fermentation.


Assuntos
Fermentação , Gases de Efeito Estufa , Microbiota , Silagem , Sorghum , Temperatura , Silagem/análise , Gases de Efeito Estufa/análise , Metano/metabolismo , Metano/análise , Dióxido de Carbono/análise , Óxido Nitroso/análise
18.
Angew Chem Int Ed Engl ; : e202413309, 2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39209802

RESUMO

Strong electron-phonon coupling can hinder exciton transport and induce undesirable non-radiative recombination, resulting in a shortened exciton diffusion distance and constrained exciton dissociation in organic solar cells (OSCs). Therefore, suppressing electron-phonon coupling is crucially important for achieve high-performance OSCs. Here, we employ the solid additive to regulating electron-phonon coupling in OSCs. The planar configuration of SA1 confers a significant advantage in suppressing lattice vibrations in the active layers, reducing the scattering of excitons by phonons caused by lattice vibrations. Consequently, a slow but sustained hole transfer process is identified in the SA1-assisted film, indicating an enhancement in hole transfer efficiency. Prolonged exciton diffusion length and exciton lifetime are achieved in the blend film processed with SA1, attributed to a low non-radiative recombination rate and low energetic disorder for charge carrier transport. As a result, a high efficiency of 20% was achieved for ternary device with a remarkable short-circuit current. This work highlights the important role of suppressing electron-phonon coupling in improving the photovoltaic performance of OSCs.

19.
Nature ; 633(8029): 465-472, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39143216

RESUMO

The newly identified type VII CRISPR-Cas candidate system uses a CRISPR RNA-guided ribonucleoprotein complex formed by Cas5 and Cas7 proteins to target RNA1. However, the RNA cleavage is executed by a dedicated Cas14 nuclease, which is distinct from the effector nucleases of the other CRISPR-Cas systems. Here we report seven cryo-electron microscopy structures of the Cas14-bound interference complex at different functional states. Cas14, a tetrameric protein in solution, is recruited to the Cas5-Cas7 complex in a target RNA-dependent manner. The N-terminal catalytic domain of Cas14 binds a stretch of the substrate RNA for cleavage, whereas the C-terminal domain is primarily responsible for tethering Cas14 to the Cas5-Cas7 complex. The biochemical cleavage assays corroborate the captured functional conformations, revealing that Cas14 binds to different sites on the Cas5-Cas7 complex to execute individual cleavage events. Notably, a plugged-in arginine of Cas7 sandwiched by a C-shaped clamp of C-terminal domain precisely modulates Cas14 binding. More interestingly, target RNA cleavage is altered by a complementary protospacer flanking sequence at the 5' end, but not at the 3' end. Altogether, our study elucidates critical molecular details underlying the assembly of the interference complex and substrate cleavage in the type VII CRISPR-Cas system, which may help rational engineering of the type VII CRISPR-Cas system for biotechnological applications.


Assuntos
Proteínas Associadas a CRISPR , Sistemas CRISPR-Cas , Domínio Catalítico , Microscopia Crioeletrônica , Arginina/metabolismo , Arginina/química , Proteínas Associadas a CRISPR/química , Proteínas Associadas a CRISPR/classificação , Proteínas Associadas a CRISPR/metabolismo , Proteínas Associadas a CRISPR/ultraestrutura , Modelos Moleculares , Ligação Proteica , Clivagem do RNA , RNA Guia de Sistemas CRISPR-Cas/química , RNA Guia de Sistemas CRISPR-Cas/metabolismo , RNA Guia de Sistemas CRISPR-Cas/ultraestrutura , Relação Estrutura-Atividade , Especificidade por Substrato , Multimerização Proteica
20.
Int J Biol Macromol ; 277(Pt 4): 134585, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39122081

RESUMO

Chitosan (CS) is commonly used as an adsorbent for removing Cu(II) from water, but it has drawbacks such as solubility in dilute acid, difficulty in recycling in powder form, and short service life. This study utilized sodium alginate (SA) as a gel carrier to encapsulate CS, combined with silicon dioxide (SiO2) to improve mechanical stability. The preparation of CS/SA/SiO2 (SSC1.0) involved physical blending, CaCl2 cross-linking, and freeze-drying. Characterization methods such as SEM-EDS, FTIR, BET, and XRD were used to analyze the structural composition of SSC1.0. The material exhibited a folded surface, porous internal cross-section, nitrogen/oxygen-containing functional groups, and thermal stability in high temperatures and various aqueous environments. The adsorption performance of SSC1.0 on Cu(II) was evaluated under different conditions, showing a maximum adsorption capacity of 47.50 mg/g. The material maintained a removal rate above 70 % after 5 cycles. SSC1.0 also showed the highest removal rate of Cu(II) when applied to mine wastewater treatment. Adsorption modeling indicated that the process was driven by chemical reactions and was spontaneous and heat-absorbing.'


Assuntos
Alginatos , Quitosana , Cobre , Microesferas , Dióxido de Silício , Poluentes Químicos da Água , Purificação da Água , Quitosana/química , Alginatos/química , Cobre/química , Adsorção , Dióxido de Silício/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Água/química , Concentração de Íons de Hidrogênio , Cinética
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