Satellite-observed land surface phenology (LSP) data have helped us better understand terrestrial ecosystem dynamics at large scales. However, uncertainties remain in comprehending LSP variations in ...Central Asian drylands. In this article, an LSP dataset covering Central Asia (45–100°E, 33–57°N) is introduced. This LSP dataset was produced based on Moderate Resolution Imaging Spectroradiometer (MODIS) 0.05-degree daily reflectance and land cover data. The phenological dynamics of drylands were tracked using the seasonal profiles of near-infrared reflectance of vegetation (NIRv). NIRv time series processing involved the following steps: identifying low-quality observations, smoothing the NIRv time series, and retrieving LSP metrics. In the smoothing step, a median filter was first applied to reduce spikes, after which the stationary wavelet transform (SWT) was used to smooth the NIRv time series. The SWT was performed using the Biorthogonal 1.1 wavelet at a decomposition level of 5. Seven LSP metrics were provided in this dataset, and they were categorized into the following three groups: (1) timing of key phenological events, (2) NIRv values essential for the detection of the phenological events throughout the growing season, and (3) NIRv value linked to vegetation growth state during the growing season. This LSP dataset is useful for investigating dryland ecosystem dynamics in response to climate variations and human activities across Central Asia.
Whereas there is a significant interest in the rapid construction of diversely substituted saturated heterocycles, direct and modular access is currently limited to the mono-, 2,3-, or ...3,4-substitution pattern. This Communication describes the straightforward and modular construction of 2,4-substituted saturated heterocycles from readily available materials in a highly stereo- and regioselective manner, which sets the stage for numerous readily accessible drug motifs. The strategy relies on chain walking catalysis.
Converting CO2 into chemical fuels with a photocatalyst and sunlight is an appealing approach to address climate deterioration and energy crisis. Metal complexes are superb candidates for CO2 ...reduction due to their tunable catalytic sites with high activity. The coupling of metal complexes with organic photosensitizers is regarded as a common strategy for establishing photocatalytic systems for visible-light-driven CO2 reduction. While most of the organic photosensitizers generally contain precious metals and are available through onerous synthetic routes, their large-scale application in the photocatalysis is limited. Halide perovskite nanocrystals (NCs) have been considered as one of the most promising light-harvesting materials to replace the organic photosensitizers due to their tunable light absorption range, low cost, abundant surface sites, and high molar extinction coefficient. Herein, we demonstrate a facile strategy to immobilize Ni(terpy)22+ (Ni(tpy)) on inorganic ligand-capped CsPbBr3 NCs and to apply this hybrid as a catalyst for visible-light-driven CO2 reduction. In this hybrid photocatalytic system, the Ni(tpy) can provide specific catalytic sites and serve as electron sinks to suppress electron–hole recombination in the CsPbBr3 NCs. The CsPbBr3-Ni(tpy) catalytic system achieves a high yield (1724 μmol/g) in the reduction of CO2 to CO/CH4, which is approximately 26-fold higher than that achieved with the pristine CsPbBr3 NCs. This work has developed a method for enhancing the performance of photocatalytic CO2 reduction by immobilizing metal complexes on perovskite NCs. The methodology we present here provides a new platform for utilizing halide perovskite NCs for photocatalytic applications.
Pro‐inflammatory microglia mainly rely on glycolysis to maintain cytokine production during ischemia, accompanied by an increase in inducible nitric oxide synthase (iNOS) and monocarboxylate ...transporter 1 (MCT1). The role of energy metabolism in the pro‐inflammatory response of microglia is currently unclear. In this study, we tested the response of microglia in mice after cerebral ischemia and simulated an energy environment in vitro using low glucose culture medium. The research results indicate that the expression levels of iNOS and arginase 1 (ARG1) increase in the ischemic mouse brain, but the upregulation of MCT1 expression is mainly present in iNOS positive microglia. In microglia exposed to low glucose conditions, iNOS and MCT1 levels increased, while ARG1 levels decreased. Under the same conditions, knocking down MCT1 in microglia leads to a decrease in iNOS levels, while overexpression of MCT1 leads to the opposite result. The use of NF‐κB inhibitors reduced the expression levels of iNOS and MCT1 in microglia. In summary, our data indicate that pyruvate maintains and enhances the NF‐κB regulated pro‐inflammatory response of microglia induced by low glucose.
Cooking fumes are important volatile organic compounds (VOCs) sources of indoor air, however, emission characteristics of the commonly used oils (canola, soybean, peanut, corn and lard) in Chinese ...cooking and health risks of the corresponding VOCs are still not clear. In this study, we sprayed the oil droplets uniformly on a pre-heated wall via a nozzle in order to obtain the cooking fumes with constant VOC compositions. Our results show that emission profiles of VOCs are similar among the five oils. The vegetable oils rich in unsaturated fatty acids emit more VOCs than the lard oil rich in saturated fatty acids, and the VOCs emitted from the soybean oil increase with increasing cooking temperatures. Water in oils always enhances VOC emissions by steam stripping at high temperatures. Moreover, oxidative radicals generated in the water-oil system facilitate oxidation of unsaturated fatty acids, producing carcinogenic aldehydes, benzenes and furans in the emitted VOCs. The carcinogenic risk order of furan > nonanal > hexanal > heptanal > octanal> 2-nonenal > benzene indicates that furan and various aldehydes are more carcinogenic than benzene compounds. The comprehensive health risk factor further reveals that the carcinogenic risks of the emitted VOCs from the five oils follow the order of peanut > canola > soybean > corn >> lard.
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•The stable VOCs was generated by a new cooking oil fume generator.•The VOCs follow the order of canola > soybean > peanut > corn » lard.•Aldehydes » alkanes and alkenes > alcohols > benzenes > furans in VOCs.•Water significantly affects concentrations of VOCs.•Furan, aldehydes and benzene have high carcinogenic risks.
Building energy consumption accounts for 36% of the overall energy end use worldwide and is growing rapidly as developing countries continue to urbanize. Understanding the energy use at urban scale ...will lay the foundation for identification of energy efficiency opportunities to be deployed at speed. China has almost half of global new constructions and plays an important role in building suitability. However, an open source national building energy consumption database is not available in China. To provide data support for building energy consumptions, this paper used a simulation method to develop an urban building energy consumption database for a pilot city in Wuhan, China. First, residential, small, and large office building archetype energy models were created in EnergyPlus to represent typical building energy consumption in Wuhan. The baseline reference model simulation results were further validated using survey data from the literature. Second, stochastic simulations were conducted to consider different design parameters and occupants’ energy usage intensity scenarios, such as thermal properties of the building envelope, lighting power density, equipment power density, HVAC (heating, ventilation and air conditioning) schedule, etc. A building energy consumption database was generated for typical building archetypes. Third, data-driven regression analysis was conducted to support quick building energy consumption prediction using key high- level building information inputs. Finally, a web-based urban energy platform and an interface were developed to support further third-party application development. The research is expected to provide fast energy efficiency building design solutions for urban planning, new constructions as well as building retrofits.
Abstract
Organosilicon compounds have shown tremendous potential in drug discovery and their synthesis stimulates wide interest. Multicomponent cross-coupling of alkenes with silicon reagents is used ...to yield complex silicon-containing compounds from readily accessible feedstock chemicals but the reaction with simple alkenes remains challenging. Here, we report a regioselective silylalkylation of simple alkenes, which is enabled by using a stable Ni(II) salt and an inexpensive
trans
−1,2-diaminocyclohexane ligand as a catalyst. Remarkably, this reaction can tolerate a broad range of olefins bearing various functional groups, including alcohol, ester, amides and ethers, thus it allows for the efficient and selective assembly of a diverse range of bifunctional organosilicon building blocks from terminal alkenes, alkyl halides and the Suginome reagent. Moreover, an expedient synthetic route toward alpha-Lipoic acid has been developed by this methodology.
Abstract Artificial intelligence has emerged as a technology to enhance productivity and improve life quality. However, its role in building energy efficiency and carbon emission reduction has not ...been systematically studied. This study evaluated artificial intelligence’s potential in the building sector, focusing on medium office buildings in the United States. A methodology was developed to assess and quantify potential emissions reductions. Key areas identified were equipment, occupancy influence, control and operation, and design and construction. Six scenarios were used to estimate energy and emissions savings across representative climate zones. Here we show that artificial intelligence could reduce cost premiums, enhancing high energy efficiency and net zero building penetration. Adopting artificial intelligence could reduce energy consumption and carbon emissions by approximately 8% to 19% in 2050. Combining with energy policy and low-carbon power generation could approximately reduce energy consumption by 40% and carbon emissions by 90% compared to business-as-usual scenarios in 2050.
Solar-powered photocatalytic hydrogen production from water using semiconductors provides an eco-friendly and promising approach for converting solar energy into hydrogen fuel. Bulk semiconductors ...generally suffer from certain limitations, such as poor visible-light utilization, rapid recombination of charge carriers, and low catalytic capability. The key challenge is to develop visible-light-driven heterojunction photocatalysts that are stable and highly active during the water splitting process. Here, we demonstrate the integration of one-dimensional (1D) CdS nanorods with two-dimensional (2D) 1T-phase dominated WS2 nanosheets for constructing mixed-dimensional heterojunctions for the photocatalytic hydrogen evolution reaction (HER). The resulting 1D CdS/2D WS2 nanoheterojunction exhibited an ultrahigh hydrogen-evolution activity of ∼70 mmol·g−1·h−1 that was visible to the naked eye, as well as long-term stability under visible light illumination. The results reveal that the synergy of hybrid nanoarchitectures and intimate interfacial contact between the 1D CdS nanorods and 1T-phase dominated 2D WS2 nanosheets facilitates charge carrier transport, which is beneficial for achieving superior hydrogen evolution.
1T-phase dominated WS2 nanosheets with high conductivity and large specific surface area were employed to construct mixed-dimensional heterojunctions for ultrahigh solar-powered photocatalytic hydrogen evolution via water splitting.
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