By virtue of a fundamentally new reaction model of azomethine ylide serving as a two‐atom synthon, we present the first example of stereodivergent preparation of γ‐butyrolactones via synergistic ...Cu/Ir‐catalyzed asymmetric cascade allylation/lactonization, and all four stereoisomers of γ‐butyrolactones bearing two vicinal stereocenters are accessible with excellent diastereoselective and enantioselective control. The chiral IrIII‐π‐allyl intermediate was separated and characterized to understand the origin of the regio‐ and stereoselectivity of the initial C−C bond formation process. Control experiments shed some light on the catalyst/substrate and catalyst/catalyst interactions in this dual catalytic system to rationalize the related kinetic/dynamic kinetic resolution process with different catalyst combinations. The enantioenriched γ‐butyrolactone products were converted into an array of structurally complex chiral molecules and organocatalysts that were otherwise inaccessible.
An unprecedented asymmetric cascade allylation/lactonization between racemic aldimine esters and racemic vinylethylene carbonate catalyzed by synergistic Cu/Ir catalysis is presented. The metalated azomethine ylide acts as a two‐atom unit and opens up access to a broad range of γ‐butyrolactones bearing two vicinal stereogenic centers in a stereodivergent manner.
A simple model for the late-time cosmic acceleration problem is presented in the Starobinsky inflation with a negative bare cosmological constant as well as a nonminimal coupling to the Higgs boson. ...After electroweak symmetry breaking, the Starobinsky inflaton has been frozen until very recently, becoming a thawing quintessence, and a comparable magnitude to the observed dark energy density can be achieved without fine-tuning. Our proposal essentially reduces the cosmological constant problem into the electroweak hierarchy problem, and its late-time behavior is also consistent with the recently proposed swampland criteria.
Multi-criteria decision analysis (MCDA) methods have become increasingly popular in decision-making for sustainable energy because of the multi-dimensionality of the sustainability goal and the ...complexity of socio-economic and biophysical systems. This article reviewed the corresponding methods in different stages of multi-criteria decision-making for sustainable energy, i.e., criteria selection, criteria weighting, evaluation, and final aggregation. The criteria of energy supply systems are summarized from technical, economic, environmental and social aspects. The weighting methods of criteria are classified into three categories: subjective weighting, objective weighting and combination weighting methods. Several methods based on weighted sum, priority setting, outranking, fuzzy set methodology and their combinations are employed for energy decision-making. It is observed that the investment cost locates the first place in all evaluation criteria and CO
2 emission follows closely because of more focuses on environment protection, equal criteria weights are still the most popular weighting method, analytical hierarchy process is the most popular comprehensive MCDA method, and the aggregation methods are helpful to get the rational result in sustainable energy decision-making.
In this study, we aim to explore the link between transformational leadership and job crafting. We predict that transformational leadership will stimulate employee job crafting (seeking resources, ...seeking challenges, and reducing demands) by increasing their adaptability; but that transformational leadership will be less effective when employees have higher levels of organizational identification. We collected data from 185 dyads of subordinates and supervisors. Supervisors rated their own transformational leadership and subordinates' adaptability, and subordinates rated their own job crafting and organizational identification. Results from structural equation modelling analyses partially supported our hypotheses. In general our findings suggest that transformational leadership is associated with more expansion job crafting (seeking resources and seeking challenges) via adaptability, particularly for employees with lower organizational identification. We conclude that transformational leadership is an important antecedent of employee adaptability and proactivity at work.
•The relationship between transformational leadership and job crafting was examined.•Employee adaptability was positioned as a mediator in the above relationship.•The above mediation effect was moderated by employee organizational identification.•Transformational leadership facilitates employee adaptability and proactivity.
SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the etiological agent responsible for the global COVID-19 (coronavirus disease 2019) outbreak. The main protease of SARS-CoV-2, M
, is ...a key enzyme that plays a pivotal role in mediating viral replication and transcription. We designed and synthesized two lead compounds (
and
) targeting M
Both exhibited excellent inhibitory activity and potent anti-SARS-CoV-2 infection activity. The x-ray crystal structures of SARS-CoV-2 M
in complex with
or
, both determined at a resolution of 1.5 angstroms, showed that the aldehyde groups of
and
are covalently bound to cysteine 145 of M
Both compounds showed good pharmacokinetic properties in vivo, and
also exhibited low toxicity, which suggests that these compounds are promising drug candidates.
The technical, economical and environmental performances of combined cooling, heating and power (CCHP) system are closely dependent on its design and operation strategy. This paper analyzes the ...energy flow of CCHP system and deduces the primary energy consumption following the thermal demand of building. Three criteria, primary energy saving (PES), annual total cost saving (ATCS), and carbon dioxide emission reduction (CDER) are selected to evaluate the performance of CCHP system. Based on the energy flow of CCHP system, the capacity and operation of CCHP system are optimized by genetic algorithm (GA) so as to maximize the technical, economical and environmental benefits achieved by CCHP system in comparison to separation production system. A numerical example of gas CCHP system for a hotel building in Beijing is given to ascertain the effectiveness of the optimal method. Furthermore, a sensitivity analysis is presented in order to show how the optimal operation strategy would vary due to the changes of electricity price and gas price.
We describe cooperative bimetallic catalysis that enables regio‐/stereodivergent asymmetric α‐allylations of aldimine esters. By employing Et3B as the key activator, racemic allylic alcohols can be ...directly ionized to form Pd or Ir‐π‐allyl species in the presence of achiral Pd or chiral Ir complexes, respectively. The less or more substituted allylic termini of the metal‐π‐allyl species are amenable to nucleophilic attack by the chiral Cu‐azomethine ylide, the formation of which is simultaneously facilitated by Et3B, affording α‐quaternary α‐amino acids with high regioselectivity and excellent stereoselectivity. The use of readily available allylic alcohols as electrophilic precursors represents an improvement from an environmental and atom/step economy perspective. Computational mechanistic studies reveal the crucial role of the Et3B additive and the origins of stereo‐ and regioselectivities by analyzing steric effects, dispersion interactions, and frontier orbital population.
The regio‐ and stereodivergent asymmetric α‐allylation of aldimine esters with racemic allylic alcohols was enabled by cooperative catalysis. The Et3B additive plays a significant role in ionizing allylic alcohols to form electrophilic metal‐π‐allyl species and simultaneously promotes the formation of nucleophilic Cu‐ylides. Computational mechanistic studies revealed the role of the Et3B additive and the origins of stereo‐ and regioselectivities.
Inflammation plays a crucial role in the pathogenesis of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Our study aimed to analyse previous inconsistent results of inflammatory markers ...in AD and MCI quantitatively.
Studies reporting concentrations of peripheral or cerebrospinal fluid (CSF) markers were included, and eligible data on AD, MCI and control were extracted. Pooled Hedges's g was adopted to illustrate comparisons, and various confounding factors were used to explore sources of heterogeneity.
A total of 170 studies were included in the meta-analysis and systematic review, which demonstrated increased peripheral levels of high-sensitivity C reactive protein (Hedges's g 0.281, p<0.05), interleukin-6 (IL-6) (0.429, p<0.005), soluble tumour necrosis factor receptor 1 (sTNFR1) (0.763, p<0.05), soluble tumour necrosis factor receptor 2 (sTNFR2) (0.354, p<0.005), alpha1-antichymotrypsin (α1-ACT) (1.217, p<0.005), IL-1β (0.615, p<0.05) and soluble CD40 ligand (0.868, p<0.005), and CSF levels of IL-10 (0.434, p<0.05), monocyte chemoattractant protein-1 (MCP-1) (0.798, p<0.005), transforming growth factor-beta 1 (1.009, p<0.05), soluble triggering receptor expressed on myeloid cells2 (sTREM2) (0.587, p<0.001), YKL-40 (0.849, p<0.001), α1-ACT (0.638, p<0.001), nerve growth factor (5.475, p<0.005) and visinin-like protein-1 (VILIP-1) (0.677, p<0.005), in AD compared with the control. Higher levels of sTNFR2 (0.265, p<0.05), IL-6 (0.129, p<0.05) and MCP-1 (0.779, p<0.05) and lower levels of IL-8 (-1.293, p<0.05) in the periphery, as well as elevated concentrations of YKL-40 (0.373, p<0.05), VILIP-1 (0.534, p<0.005) and sTREM2 (0.695, p<0.05) in CSF, were shown in MCI compared with the control. Additionally, increased peripheral sTNFR1 (0.582, p<0.05) and sTNFR2 (0.254, p<0.05) levels were observed in AD compared with MCI.
Significantly altered levels of inflammatory markers were verified in comparison between AD, MCI and control, supporting the notion that AD and MCI are accompanied by inflammatory responses in both the periphery and CSF.
Lung cancer is a malignant tumor characterized by a rapid proliferation rate, less survivability, high mortality, and metastatic potential. This review focuses on updated research about the clinical ...application of traditional Chinese medicine (TCM) as an adjuvant therapy to lung cancer treatment and the mechanisms of TCM effect on lung cancer in vitro and in vivo. We summarized the recent 5 years of different research progress on clinical applications and antitumor mechanisms of TCM in the treatment of lung cancer. As a potent adjuvant therapy, TCM could enhance conventional treatments (chemotherapy, radiation therapy, and epidermal growth factor receptors EGFRs tyrosine kinase inhibitors TKIs) effects as well as provide synergistic effects, enhance chemotherapy drugs chemosensitivity, reverse drug resistance, reduce adverse reactions and toxicity, relieve patients' pain and improve quality of life (QOL). After treating with TCM, lung cancer cells will induce apoptosis and/or autophagy, suppress metastasis, impact immune reaction, and therapeutic effect of EGFR-TKIs. Therefore, TCM is a promisingly potent adjuvant therapy in the treatment of lung cancer and its multiple mechanisms are worthy of an in-depth study.
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