•The spatial-temporal characteristics of carbon emissions are different for each land use type.•Construction land is the main source of carbon.•Carbon emissions in the Yellow River Delta were ...spatially clustered.•The distribution of carbon emissions is larger in the “east-west” than in the “north-south”.
Land use is a major source of anthropogenic carbon emissions and a driver of climate change, so it is necessary to explore the spatial and temporal distribution characteristics of carbon emissions from different land use types. Based on the land use type data and fossil energy consumption data in the same period, we analyzed the spatial and temporal distribution characteristics of carbon emissions in the Yellow River Delta from 2000 to 2019 by constructing a carbon emission model, carbon footprint and Moran’s I index. The empirical results show that total net carbon emissions in the Yellow River Delta increased from 3.1×1010kg to 1.5×1011kg during 2000–2019. Construction land is the main source of carbon, while forest land and water contribute more to the total carbon sink in the study area. Carbon emissions in the Yellow River Delta were spatially clustered, characterized by a larger distribution of carbon emissions in the “east-west” direction than in the “north-south” direction. The results of the study are conducive to a comprehensive understanding of the spatial distribution pattern of land use carbon sources/sinks in the Yellow River Delta, and provide a certain reference basis for the formulation of low-carbon economic policies in the region.
Exploration of effective ways to integrate various functional species into hydrogen‐bonded organic frameworks (HOFs) is critically important for their applications but highly challenging. In this ...study, according to the “bottle‐around‐ship” strategy, core–shell heterostructure of upconversion nanoparticles (UCNPs) and HOFs was fabricated for the first time via a ligand‐grafting stepwise method. The UCNPs “core” can effectively upconvert near‐infrared (NIR) irradiation (980 nm) into visible light (540 nm and 653 nm), which further excites the perylenediimide‐based HOF “shell” through resonance energy transfer. In this way, the nanocomposite inherits the high porosity, excellent photothermal and photodynamic efficiency, NIR photoresponse from two parent materials, achieving intriguing NIR‐responsive bacterial inhibition toward Escherichia coli. This study may shed light on the design of functional HOF‐based composite materials, not only enriching the HOF library but also broadening the horizon of their potential applications.
In this study, core–shell heterostructures of upconversion nanoparticles (UCNPs) and hydrogen‐bonded organic frameworks (HOFs) were fabricated via a stepwise ligand‐grafting method. The UCNP “core” can effectively upconvert near‐infrared (NIR) irradiation into visible ranges, which can further excite the HOF “shell” to achieve near‐infrared‐responsive photothermal and photodynamic bacterial inhibition.
Crop residue is an abundant and lucrative biomass resource in China, which is expected to decrease its reliance on coal and petroleum through the use of crop residue. This study was conducted with ...the data of crop production released by the National Bureau of Statistics of China and 1417 valid face-to-face questionnaires on residue utilizations. It was found that the crop residue increased from 725.47 Mt in 2007 to 897.06 Mt in 2016 at the annual rate of 2.63%. It amounted for 897.06 Mt including 781.32 Mt field residue and 115.74 Mt and process residue, respectively in 2016. Field residue retained in field exhibited the highest ratio (35.19%), for bioenergy use was less than 1%. A total amount of available field residue (AFR) for bioethanol was 254.57 Mt in 2016. Maize provided the greatest quantity of AFR (95.00 Mt), followed by rice (78.90 Mt) and wheat (18.89 Mt), sum of three accounted for 76% AFR in China. The largest AFR was found in Heilongjiang (39.79 Mt), followed by Henan (31.03 Mt) and Jilin (22.51 Mt). The density of AFR exhibited high in NEC and CSC and southeast provinces of SWC. The bioethanol potential was 124.3 Mt in 2016, with maize, rice and wheat residues representing 77.8% of the total. The four top-ranked provinces of bioethanol potential were Heilongjiang, Henan, Jilin, and Sichuan. It was suggested that financial and taxation support are necessary to promote cellulosic bioethanol research and industrial use in its early stage.
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•China's crop residue increased from 725.47 Mt in 2007 to 897.06 Mt in 2016.•Available residue of maize, rice, and wheat were shared 75.7% of total in 2016.•Field residue retained (35.19%) and burnt (25.20%) in the field were the highest.•Heilongjiang, Henan and Jilin produced the highest available residues with 93.3 Mt.•Bioethanol production potential from field residue was 124.3 Mt in total.
Zirconium-based metal–organic frameworks (Zr-MOFs) have been demonstrated as potent catalysts for the hydrolytic detoxification of organophosphorus nerve agents and their simulants. However, the ...practical implementation of these Zr-MOFs is limited by the poor processability of their powdered form and the necessity of water media buffered by a volatile liquid base in the catalytic reaction. Herein, we demonstrate the efficient solid-state hydrolysis of a nerve agent simulant (dimethyl-4-nitrophenyl phosphate, DMNP) catalyzed by Zr-MOF-based mixed matrix membranes. The mixed matrix membranes were fabricated by incorporating MOF-808 into the blending matrix of poly(vinylidene fluoride) (PVDF), poly(vinylpyrrolidone) (PVP), and imidazole (Im), in which MOF-808 provides highly active catalytic sites, the hydrophilic PVP helps to retain water for promoting the hydrolytic reaction, and Im serves as a base for catalytic site regeneration. Impressively, the mixed matrix membranes displayed excellent catalytic performance for the solid-state hydrolysis of DMNP under high humidity, representing a significant step toward the practical application of Zr-MOFs in chemical protective layers against nerve agents.
cis‐Prenyltransferases (cis‐PTs) catalyze the sequential head‐to‐tail condensation of isopentenyl diphosphate (IPP) to allylic diphosphates, producing mixed E–Z prenyl diphosphates of varying ...lengths; however, the specific enzymes synthesizing cis‐C25 prenyl diphosphates have not been identified. Herein, we present the discovery and characterization of a cis‐geranylfarnesyl diphosphate synthase (ScGFPPS) from Streptomyces clavuligerus. This enzyme demonstrates high catalytic proficiency in generating six distinct cis‐polyisoprenoids, including three C25 and three C20 variants. We determined the crystal structure of ScGFPPS. Additionally, we unveil the crystal structure of nerylneryl diphosphate synthase (NNPS), known for synthesizing an all‐cis‐C20 polyisoprenoid. Comparative structural analysis of ScGFPPS and NNPS has identified key differences that influence product specificity. Through site‐directed mutagenesis, we have identified eight single mutations that significantly refine the selectivity of ScGFPPS for cis‐polyisoprenoids. Our findings not only expand the functional spectrum of cis‐PTs but also provide a structural comparison strategy in cis‐PTs engineering.
A cis‐geranylfarnesyl diphosphate synthase (ScGFPPS) was discovered from Streptomyces clavuligerus. In vivo and in vitro experiments demonstrated that ScGFPPS catalyzed the condensation of DMAPP, GPP, and FPP with IPP to yield six cis‐polyisoprenoids. Structural variances between ScGFPPS and NNPS facilitated the strategic bioengineering of ScGFPPS to achieve high product specificity.
A mechanochemical direct selenocyanation of arenes/heterocyclic arenes with electrophilic selenocyanating reagents to access (hetero)aryl selenocyanates has been developed. This protocol provided an ...efficient strategy to access various aromatic selenocyanates in yields up to 99 % under ball‐milling reaction conditions within 60 minutes. Gram‐scale reaction and further transformations of the product were conducted to demonstrate the synthetic utilities of this method.
Various aromatic selenocyanates were successfully delivered in moderate to excellent yields (up to 99 % yield) via direct selenocyanation of arenes/heterocyclic arenes with electrophilic selenocyanating reagents using Mechanochemistry. This protocol exhibits the advantages of operationally simple, environmentally friendly and time‐economy.
Multifunctional nanomaterials with simple structure and good biosafety, integrating multimodal imaging and therapeutic functions, can facilitate the development of clinical cancer treatments. Here, a ...simple but powerful pure bismuth based nanoparticle (Gd-PEG-Bi NPs) was developed from pure Bi NPs and gadolinium-diethylenetriaminepentaacetic acid-bis-tetradecylamide, which not only shows high quality MRI/CT/PAI triple-modal imaging, but can also be a potent photothermal therapy agent under the guidance of the triple-modal imaging. The Gd-PEG-Bi NPs showed good stability and excellent biocompatibility. In vitro and in vivo study demonstrated that Gd-PEG-Bi NPs have ultrahigh X-ray attenuation coefficient, short T1 relaxation time in MRI, and strong PAI signal. Following the imaging diagnosis, the excellent light-to-heat conversion efficiency of Gd-PEG-Bi NPs was capable of suppressing the tumor growth effectively under near-infrared laser radiation in vivo. Such multifunctional nanoparticles were ideal candidates for cancer diagnosis and treatment.
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•A simple and powerful pure bismuth based nanoparticle was developed.•The pure bismuth based nanoparticle showed excellent light-to-heat conversion efficiency.•The bismuth nanoparticle can provide MRI/CT/PAI multimodal imaging and photothermal therapy.
Regiodivergent formal 5+2- and 4+2-annulation reactions of indole derivatives with 2-(2-alkynyl)aryl cyclopropane-1,1-diesters (ACPs) have been developed. A series of tetracyclic indole derivatives ...were delivered in a 77% average yield with excellent regioselectivities enabled by Au(
i
)/Sc(
iii
) bimetallic relay catalysis. A gram-scale reaction and further transformation of the resulting tetracyclic indoles demonstrated the practical utility of this protocol. Moreover, the photophysical properties of the obtained multicyclic compounds were also investigated.
A series of benzo
b
carbazole and cyclohepta
b
indole derivatives were afforded in a 77% average yield with excellent regioselectivities enabled by Au(
i
)/Sc(
iii
) bimetallic relay catalysis.
Teleost fish skin serves as the first line of defense against pathogens. The interaction between pathogen and host skin determines the infection outcome. However, the mechanism(s) that modulate ...infection remain largely unknown. A proper tissue culture model that is easier to handle but can quantitatively and qualitatively monitor infection progress may shed some lights. Here, we use striped catfish (Pangasius hypophthalmus) to establish an ex vivo skin explant tissue culture model to explore host pathogen interactions. The skin explant model resembles in vivo skin in tissue morphology, integrity, and immune functionality. Inoculation of aquatic pathogen Aeromonas hydrophila in this model induces epidermal exfoliation along with epithelial cell dissociation and inflammation. We conclude that this ex vivo skin explant model could serve as a teleost skin infection model for monitoring pathogenesis under various infection conditions. The model can also potentially be translated into a platform to study prevention and treatment of aquatic infection on the skin in aquaculture applications.
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