Sc(OTf)3-mediated 1,3-dipolar cycloaddition-ring cleavage-rearrangement: a highly stereoselective access to Z-ß-enaminonitriles.

A novel and highly stereoselective synthesis of Z-ß-enaminonitriles from azides and α,ß-unsaturated nitriles is reported. The reaction proceeds via a 1,3-dipolar cycloaddition-ring cleavage-rearrangement cascade mediated by a catalytic amount of Sc(OTf)3. A plausible reaction mechanism for this process is depicted.

Allocation of provincial carbon emission allowances under China's 2030 carbon peak target: A dynamic multi-criteria decision analysis method.

To balance China's socio-economic development and emission reduction goals, a fair and effective provincial carbon emission allowance (CEA) allocation is necessary. By considering the implied emissions of inter-provincial power transfer, this study designed a dynamic multi-criteria CEA allocation model based on four criteria-egalitarianism, historical responsibility, emission reduction capability, and emission efficiency-to calculate the provincial CEA year by year before 2030. The efficiency and fairness of the CEA scheme were evaluated through the Data envelopment analysis (DEA) model, the environmental Gini coefficient, and its grouped decomposition method. The national overall CEA, the results revealed, will peak during the 15th Five-Year Plan (FYP) period. Specifically, the CEA for eastern and central China is expected to peak first during the 14th FYP period, while the northeast region's CEA remains stable and that of the western region continues to grow. Provinces with high carbon emissions, high carbon emission intensity and high per capita carbon emissions and provinces with particularly high carbon emissions will face great pressure regarding emission reduction, and their CEA peaks are expected to arrive before 2025 and 2030 respectively. The CEA of the less-developed provinces will have a surplus. In terms of time, the high-emission provinces face greater emission reduction pressure during the 15th FYP period than during the 14th FYP period. In terms of scheme evaluation, the scheme achieved a double improvement in fairness and efficiency compared with the current actual emissions of various provinces. Reducing the differences in per capita CEA between the different regions and provinces in the western and eastern regions will help improve the scheme's fairness. This study overcomes the existing researches' shortcomings on the large differences in the distribution of emission reduction pressures in key provinces and is more feasible in practice.

Research on the national climate governance system toward carbon neutrality-A critical literature review.

Global climate governance has entered the era of carbon neutrality, as a growing number of countries have set the goal of carbon neutrality for long-term emissions reduction toward the mid-21st century. In 2020, China also pledged itself to the goal of carbon neutrality, which creates an urgent demand for this country to establish a systematic and integrated national climate governance system. Against this background, this paper conducts a systematic literature review of climate governance systems from the perspectives of top-level design and the governance paradigm to bring insights into climate governance toward carbon neutrality. The results show that although there are interactions between decarbonization and other environmental, social and economic fields, research gaps still exist when enhancing climate governance toward carbon neutrality. For example, issues regarding incorporating climate factors into the overall economic and social layout, strengthening the capacity of data collection relevant to climate adaptation, integrating climate mitigation and adaption actions, as well as connecting domestic climate governance and international cooperation, need to be further addressed. In addition, within the national governance system, studies combining both regional and sectoral concerns and the intertemporal dynamic allocation mechanism need to be further addressed when China decomposes its national climate target. Moreover, the division of power between the central government and local government, as well as the communication scheme between government and non-state actors, also turns out to be important for effective governance. Based on this analysis, policy implications are further proposed for China's formulation and implementation of long-term strategies of climate governance toward carbon neutrality.

DEPTOR exacerbates bone-fat imbalance in osteoporosis by transcriptionally modulating BMSC differentiation.

Bone marrow-derived mesenchymal stem cells (BMSCs) tend to differentiate into adipocytes rather than osteoblasts in osteoporosis and other pathological conditions. Understanding the mechanisms underlying the adipo-osteogenic imbalance greatly contributes to the ability to induce specific MSC differentiation for clinical applications. This study aimed to explore whether DEP-domain containing mTOR-interacting protein (DEPTOR) regulated MSC fate and bone-fat switch, which was indicated to be a key player in bone homeostasis. We found that DEPTOR expression decreased during the osteogenesis of BMSCs but increased during adipogenesis and the shift of cell lineage commitment of BMSCs to adipocytes in mice with osteoporosis. DEPTOR facilitated adipogenic differentiation while preventing the osteogenic differentiation of BMSCs. Deptor ablation in BMSCs alleviated bone loss and reduced marrow fat accumulation in mice with osteoporosis. Mechanistically, DEPTOR binds transcriptional coactivator with a PDZ-binding motif (TAZ) and inhibits its transactivation properties, thereby repressing the transcriptional activity of RUNX2 and elevating gene transcription by peroxisome-proliferator-activated receptor-gamma. TAZ knockdown in BMSCs abolished the beneficial role of Deptor ablation in bone-fat balance in mice. Together, our data indicate that DEPTOR is a molecular rheostat that modulates BMSC differentiation and bone-fat balance, and may represent a potential therapeutic target for age-related bone loss.

Preparation of polysaccharides from wax gourd.

Preparation of polysaccharides from the wax gourd was studied. The crude polysaccharides were extracted by ethanol precipitation, and deproteinized by the hydrochloric acid method. The deproteinized polysaccharides were separated by column chromatography to obtain the pure polysaccharides. The pure polysaccharides have a ß-D-pyranosidic bond, and their molecular weight distribution is about 22,500. It was indicated that the final product had much more purity by IR spectrum analysis, UV absorption spectrum analysis, and phenol-sulfuric acid method, respectively. It was proved that wax gourd polysaccharides were composed of rhamnose, xylose, arabinose, mannose, glucose, and galactose by thin layer chromatography.

Vehicle mix evaluation in Beijing's passenger-car sector: From air pollution control perspective.

The transport sector has been one of the largest source of carbon emission and urban air pollutants. The research on the coordinated development of pollutant and carbon emission reduction in transport industry is helpful to the realization of urban pollutant prevention and carbon emission reduction, especially in big cities. Thus, a multi-period bottom-up vehicle development mathematical model is proposed to analyze the technology development path, emission path and energy structure adjustment path, and the synergistic benefits of carbon dioxide (CO2) emission reduction under a expected air pollution emission standard. Four pollutants, carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulate matter (PM), generated from the vehicle are considered in this model. Then, the proposed model is used to analyze the related vehicle structure and energy consumption under the expected emission standards for Beijing during 2020 and 2035. The technology development path, emission path and energy structure adjustment path are examined, and the synergistic benefits of CO2 emission reduction are also studied. Some important implication are found as follows: (1) Even with the goal of environmental pollution control only, new energy vehicles will have an explosive growth period, starting from about 2025. (2) Strict air pollution emission policies do not always lead to the rapid development of new energy vehicles before 2025. (3) The four main pollutants show different levels of synergistic effect among which CO on HC and NOx on PM are obvious, respectively. (4) Even under the control of the air pollution policy, the synergistic effect to CO2 emission reduction is also obvious. Compared to the baseline case, the reduction benefit from the MILD and STRICT environmental policies are 30 and 70 million yuan, respectively.

Physical and virtual carbon metabolism of global cities.

Urban activities have profound and lasting effects on the global carbon balance. Here we develop a consistent metabolic approach that combines two complementary carbon accounts, the physical carbon balance and the fossil fuel-derived gaseous carbon footprint, to track carbon coming into, being added to urban stocks, and eventually leaving the city. We find that over 88% of the physical carbon in 16 global cities is imported from outside their urban boundaries, and this outsourcing of carbon is notably amplified by virtual emissions from upstream activities that contribute 33-68% to their total carbon inflows. While 13-33% of the carbon appropriated by cities is immediately combusted and released as CO2, between 8 and 24% is stored in durable household goods or becomes part of other urban stocks. Inventorying carbon consumed and stored for urban metabolism should be given more credit for the role it can play in stabilizing future global climate.

Palladium-catalyzed formation of phenolic compounds by reaction of carbonyl compounds with carbon dioxide.

The use of carbon dioxide as a renewable and environmentally friendly source of carbon is highly attractive. A novel and efficient protocol for the synthesis of phenolic compounds from carbonyl compounds and carbon dioxide in the presence of a catalytic amount of Pd(OAc)(2) has been developed. This reaction is appealing for industries and is a tool for the sequestration of carbon dioxide.