An organocatalytic asymmetric synthesis of directly linked benzothiazole‐dihydroimidazoles with two adjacent tertiary‐quaternary stereocenters through a Mannich‐type reaction of isocyanoacetates with ...N‐(2‐benzothiazolyl)imines is disclosed. When employing bifunctional dihydroquinine‐derived squaramide as catalyst, moderate to excellent yields (up to 97 % yield), moderate diastereoselectivities and excellent enantioselectivities (up to >99 % ee) were obtained for a variety of substrates. In addition, the transformation of the resulted directly linked benzothiazole‐dihydroimidazole into highly functionalized α,β‐diamino esters was also demonstrated.
A practical and efficient transition‐metal‐free selective protocol has been developed for the direct synthesis of chiral directly linked benzothiazole‐dihydroimidazoles with two adjacent tertiary‐quaternary stereocenters through asymmetric Mannich‐type reaction of α‐isocyanoacetates with N‐(2‐benzothiazolyl)imines catalyzed by dihydroquinine‐derived squaramide under the mild conditions for the first time.
The first palladium‐catalyzed allylation of isocyanoacetates with vinyl aziridines has been developed. The reaction conditions were suitable for a variety of α‐aryl isocyanoacetates as well as ...N‐substituted vinyl aziridines, affording the corresponding allylation products in moderate to high yields (up to 98 %) along with excellent stereoselectivity and regioselectivity. Transformations of the allylation products into trans‐4,5‐dehydrolysine analogues and a highly functionalized proline ester derivative were further demonstrated, and a preliminary asymmetric version of the reaction has also been evaluated.
A practical and efficient protocol has been developed for the direct synthesis of α‐allylated isocyanoacetates through palladium‐catalyzed highly regio‐ and stereoselective allylation of α‐isocyanoacetates with vinyl aziridines under mild conditions.
Researchers face difficulties in studying the effects of driveline efficiency on car fuel economy via bench and road tests because of long working periods, high costs, and heavy workloads. To ...simplify the study process and shorten test cycles, a car fuel economy simulation forecast method for combining computer simulation forecasting with bench tests is proposed. Taking a continuously variable transmission (CVT) as the research object, a transmission efficiency model based on a bench test is constructed. An optimal economic variogram based on the original CVT variogram, the boundary conditions of vehicle performance, the road conditions and the driving behavior of the driver is generated in the Gear Shift Program (GSP)-Generation module in AVL Cruise. And on this basis a driveline simulation model that can calculate the fuel consumption based on the driveline data of a test car is built. The model is used to forecast fuel consumption and calculate real-time CVT efficiency under different conditions. Contrastive analyses on simulation results and real car drum test results are made. The largest error between simulation results and drum test results in driving cycles is 4.099%, which is 5.449% under constant velocity condition in driver control mode and 4.2% under constant velocity condition in automatic cruise mode. The results confirm the feasibility of the method and the good performance of the driveline simulation model in accurately forecasting fuel consumption. The method can efficiently investigate the effects of driveline efficiency on car fuel economy. Moreover, this research provides instruction for accurately forecasting fuel economy as well as references for studies on the effects of drivelines on car fuel economy.
•One novel fluorescent 3D Co-CP has been strategically prepared.•Co-CP displays great chemical and water stabilities.•Co-CP shows multi-target fluorescence sensing of hypochlorite, nitrofuran ...antibiotics (NFZ and NFT) and acetylacetone via “turn-off” effects.
The abuse of biological and environmental related materials, such as pharmaceutical antibiotics, volatile organic chemicals and toxic ions has become a topical issue that draws the global attention. Thus, the exploration of effective methods for the rapid recognition of contaminants at low concentrations is critical for curtailing pollution and identifing environmental risks. Previous reports have shown that NH2-functionalized LCPs can serve as effective traps of hypochlorite owing to their rapid chemical reaction with hypochlorite. Herein, we strategically prepared a novel three-dimensional (3D) CP, Co2(edda)(datrz)(H2O)2·EtOH (Co-CP), using NH2-decorated triazole ligand 3,5-diamino-1,2,4-triazole (datrz) combined with semirigid tetracarboxylic acid 5,5′-(ethane-1,2-diylbis(oxy)) diisophthalic acid (H4edda). The prepared Co-CP features a pcu topology with point symbol of {412.63}. This material exhibits high structural stability in acidic-basic aqueous solution of broad pH scope (1–11), which is favorable for fluorescence detection in aqueous medium. As expected, the open -NH2 sites within the framework endow this fluorescent CP with remarkable detectability towards hypochlorite in aqueous media. Furthermore, Co-CP also displays satisfactory fluorescence response for sensing nitrofuran antibiotics (NFT and NFZ) and acetylacetone with high sensitivity and selectivity along with great interference immunity. Through exhaustive theories calculations and experimental surveys, the possible mechanisms have also been thoroughly investigated. The CP-based multifunctional fluorescent switch designed in this work expands the application of such materials in biological and environmental related areas.
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•One new fluorescent 2D Cd-CP has been synthesized and fully characterized.•Cd-CP displays great stability in aqueous system.•Cd-CP serves as multifunctional fluorescent sensor for AA, NFT / NFZ and ...ACAC.
The concentrations of hazardous volatile organic compounds (VOCs), pharmaceutical antibiotics and biomolecules in water systems are closely related with public health and ecological security. Thus, the convenient and accurate detection of these harmful items can not only reflect the state of human health but also evaluate the level of homologous contamination in the environment. To this end, a new Cd(II)-CP ({Cd3L2(bmoe)·DMF}n) with excellent luminescence properties was designed by employing the semi-rigid tricarboxylic acid 4-(2′,3′-dicarboxylphenoxy) (H3L) and N-donor ligand 1,1′-bis(1H-benzimidazolyl) oxydiethane (bmoe). The as-prepared Cd-CP features the unique uninodal sql topology. Benefiting from its great stability in the aqueous system, Cd-CP serves as a versatile multifunctional fluorescent sensor for different analytes, ascorbic acid (AA), nitrofuran antibiotics nitrofurantoin (NFT) and nitrofurazone (NFZ) and acetylacetone (ACAC). The established methods are characterized with impressive low detection limits, ultrafast response time, high sensitivity, strong anti-interference ability, as well as reliable reproducibility. Experimental and theoretical calculation reveals that the collaborative effects of Förster resonance energy transfer (FRET), inner-filter effect (IFE) and photoinduced electron transfer (PET) are the most probable causes behind the quenching of the CP's fluorescence signal.
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Researchers face difficulties in studying the effects of driveline efficiency on car fuel economy via bench and road tests because of long working periods,high costs,and heavy workloads.To simplify ...the study process and shorten test cycles,a car fuel economy simulation forecast method for combining computer simulation forecasting with bench tests is proposed.Taking a continuously variable transmission (CVT) as the research object,a transmission efficiency model based on a bench test is constructed.An optimal economic variogram based on the original CVT variogram,the boundary conditions of vehicle performance,the road conditions and the driving behavior of the driver is generated in the Gear Shift Program (GSP)-Generation module in AVL Cruise.And on this basis a driveline simulation model that can calculate the fuel consumption based on the driveline data of a test car is built.The model is used to forecast fuel consumption and calculate real-time CVT efficiency under different conditions.Contrastive analyses on simulation results and real car drum test results are made.The largest error between simulation results and drum test results in driving cycles is 4.099％,which is 5.449％ under constant velocity condition in driver control mode and 4.2％ under constant velocity condition in automatic cruise mode.The results confirm the feasibility of the method and the good performance of the driveline simulation model in accurately forecasting fuel consumption.The method can efficiently investigate the effects of driveline efficiency on car fuel economy.Moreover,this research provides instruction for accurately forecasting fuel economy as well as references for studies on the effects of drivelines on car fuel economy.
AIM： To investigate the health related quality of life （HRQoL） and psychological outcome of donors after living donor liver transplantation. METHODS： Participants were 92 consecutive liver transplant ...donors who underwent hepatectomy with- out middle hepatic vein at West China Hospital of Sichuan University between January 2007 and Sep- tember 2010. HRQoL was measured using the Chinese version of the Medical Outcomes Study Short Form-36 （SF-36）, and psychological symptoms were measured using the Symptom Checklist-90-Revised （SCL-90-R）. Data collected from donors were compared to previ- ously published data from the general population. Clin- ical and demographic data were collected from medical records and questionnaires.RESULTS： The general health score of the SF-36 was significantly lower in females （59.78 ± 12.25） than in males （75.83 ± 22.09）. Donors more than 40 years old scored higher in social functioning （85.71 ± 14.59） and mental health （82.61 ± 20.00） than those younger than 40 （75.00 ± 12.13, 68.89 ± 12.98; social func- tioning and mental health, respectively）. Donors who had surgery more than two years prior to the study scored highest in physical functioning （P = 0.001） and bodily pain （P = 0.042） while those less than one year from surgery scored lowest. The health of the liver recipient significantly influenced the general health （P = 0.042）, social functioning （P = 0.010）, and role- emotional （P = 0.028） of donors. Donors with full-time employment scored highest in role-physical （P = 0.005）, vitality （P = 0.001）, social functioning （P = 0.016）, mental health （P 〈 0.001）, the physical component summary scale （P 〈 0.001）, and the mental compo- nent summary scale （MCS） （P 〈 0.001）. Psychological measures indicated that donors were healthier than the general population in obsessive-compulsive behav- ior, interpersonal sensitivity, phobic anxiety, and para- noid ideation. The MCS of the SF-36 was significantly correlated with most symptom scores of the SCL-90-R. CONCLUSION： HRQoL and psychological outcome were favorable in living liver transplant donors after donation. Specifically, gender, age, time since operation, recipient health condition, and employment after donation, influenced postoperative quality of life.
Aim： Recent evidence shows that localization of mRNAs and their protein products at cellular protrusions plays a decisive function in the metastasis of cancer cells. The aim of this study was to ...identify the variety of proteins encoded by protrusion-localized mRNAs and their roles in the metastasis and invasion of liver cancer cells. Methods： Highly metastatic hepatocellular carcinoma cell line HCCLM3 and non-metastatic hepatocellular carcinoma cell line SMMC-7721 were examined. Cell protrusions （Ps） were separated from cell bodies （CB） using a Boyden chamber assay; total mRNA population in CB and Ps fractions was analyzed using high-throughput direct RNA sequencing. The localization of STAT3 mRNA and protein at Ps was confirmed using RT-qPCR, RNA FISH, and immunofluorescence assays. Cell migration capacity and invasiveness of HCCLM3 cells were evaluated using MTT, wound healing migration and in vitro invasion assays. The interaction between Stat3 and growth factor receptors was explored with co-immunoprecipitation assays. Results： In HCCLM3 cells, 793 mRNAs were identified as being localized in the Ps fraction according to a cut-off value （Ps/CB ratio） 〉1.6. The Ps-localized mRNAs could be divided into 4 functional groups, and were all closely related to the invasive and metastatic properties. STAT3 mRNA accumulated in the Ps of HCCLM3 cells compared with non-metastatic SMMC-7721 cells. Treatment of HCCLM3 cells with siRNAs against STAT3 mRNA drastically decreased the cell migration and invasion. Moreover, Ps-localized Stat3 was found to interact with pseudopod-enriched platelet-derived growth factor receptor tyrosine kinase （PDGFRTK） in a growth factor- dependent manner. Conclusion： This study reveals STAT3 mRNA localization at the Ps of metastatic hepatocellular carcinoma HCCLM3 cells by combining application of genome-wide and gene specific description and functional analysis.
Metallic glasses (MGs) with the metastable nature and random atomic packing structure have attracted large attention in the catalytic family due to their superior catalytic performance. In contrast, ...their crystalline counterparts are restricted by the highly ordered packing structure, fewer surface active sites, and crystallographic defects for catalytic activity. The uncertainty of the different catalytic mechanisms and the intrinsic characteristics correlated to MGs and their crystalline counterparts become a major impediment to promote their catalytic efficiencies and widespread applications. Herein, it is reported that the excellent catalytic behavior in Fe‐based MGs goes through a detrimental effect with the partial crystallization, but receives a compelling rejuvenation in the full crystallization. Further investigation reveals that multiphase intermetallics with electric potential differences in fully crystallized alloys facilitate the formation of galvanic cells. More importantly, extensively reduced grain boundaries due to grain growth greatly weaken electron trapping and promote inner electron transportation. The relatively homogenous grain‐boundary corrosion in the intermetallics contributes to well‐separated phases after reaction, leading to refreshment of the surface active sites, thereby quickly activating hydrogen peroxide and rapidly degrading organic pollutants. The exploration of catalytic mechanisms in the crystalline counterparts of MGs provides significant insights into revolutionize novel catalysts.
Fully crystallized alloys gained by annealing of metallic glasses show excellent rejuvenated catalytic capabilities for ultrafast activation of peroxide. As galvanic cells form in the fully crystallized alloys, a grain growth contributing to extensively reduced grain boundaries greatly weakens electron trapping and promotes inner electron transportation, providing a significant insight into exploit novel catalysts.
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