Umpolung reactions of C=X bonds(X=O,N)are valuable ways of constructing new C–C bonds,which are sometimes difficult to be constructed using traditional synthetic pathways.Classical polarity inversion of C=X bonds(X=O...Umpolung reactions of C=X bonds(X=O,N)are valuable ways of constructing new C–C bonds,which are sometimes difficult to be constructed using traditional synthetic pathways.Classical polarity inversion of C=X bonds(X=O,N)usually requires air or moisture‐sensitive and strong reducing agents,which limit the feasibility of substrate scope.Herein we describe a photo‐induced reductive cross‐coupling reaction of aldehydes,ketones and imines with electron‐deficient arenes(aromatic nitriles)using fac‐Ir(ppy)3as a photocatalyst and diisopropylethylamine(DIPEA)as a terminal reductant under visible light irradiation.Mild conditions and high yields mean that this new polarity inversion strategy can be used with aryl‐substituted alcohols and amines.Spectroscopic studies and control experiments have demonstrated the oxidative quenching of Ir(ppy)3*by electron‐deficient arenes involved in the key step for the C–C bond formation.展开更多
Objective G719 X is the most frequently seen uncommon mutation of the epidermal growth factor receptor(EGFR) gene, which is a point mutation at exon 18 with three common subtypes, G719 A/G719 C/G719 S. This study expl...Objective G719 X is the most frequently seen uncommon mutation of the epidermal growth factor receptor(EGFR) gene, which is a point mutation at exon 18 with three common subtypes, G719 A/G719 C/G719 S. This study explored the clinicopathological characteristics of the G719 X mutation and investigated the efficacy of EGFR-tyrosine kinase inhibitor(TKI) treatment and chemotherapy in patients with the G719 X mutation; the survival rate after these different treatment modalities were then analyzed in order to provide evidence for clinical treatment.Methods Clinical data of 41 patients with the G719 X mutation admitted in the Beijing Chest Hospital, Capital Medical University from September 2014 to July 2018, were collected and the EGFR mutations were detected by amplification refractory mutation system-polymerase chain reaction(ARMS-PCR). The clinicopathological characteristics of the G719 X mutation were analyzed, and the relationship among the G719 X mutation, the efficacy of different treatment modalities, and the progression-free survival(PFS) was analyzed. Results Of the 41 cases, 24(58.5%) were G719 X single mutations and 17(41.5%) were compound mutations, including G719 X/S768 I, G719 X/L861 Q, G719 X/19 del, and G719 X/c-Met compound mutation. The objective response rate(ORR) of first-line EGFR-TKI therapy was 50%(6/12), the disease control rate(DCR) was 83.3%(10/12), and the median PFS(mPFS) was 9 months. After resistance to EGFR-TKI in the previous treatment, the ORR(71.4%, 5/7) and DCR(100%, 7/7) were still high following EGFR-TKIs, by an mPFS of 8 months. The ORR of chemotherapy was 33.3%(2/6), the DCR was 100%(6/6), and the mPFS was 6 months. Conclusion G719 X is an uncommon mutation of the EGFR gene and is sensitive to many EGFR-TKIs. It can be treated with the second-or third-generation EGFR-TKIs after resistance to the first-generation EGFR-TKIs. G719 X mutation also showed favorable effect to chemotherapy.展开更多
To improve the bearing pressure capacity of ultrahigh pressure apparatus,the internal autofrettaged cylinder with interlayer pressure(ACCIP)is introduced,and the analytical model for the ACCIP structure and its deriva...To improve the bearing pressure capacity of ultrahigh pressure apparatus,the internal autofrettaged cylinder with interlayer pressure(ACCIP)is introduced,and the analytical model for the ACCIP structure and its derivation are presented as well.Calculation showed that the ACCIP method enhance bearing pressure of the apparatus obviously;optimization results revealed that under the working pressure pw=1.07σs and different radius ratios,the ACCIP method can keep the apparatus in deformed-elastically state;And when the pw=1.07σs,the minimum radius ratio was approximate 3.29,in this case,no yielding happened.The above results demonstrate that the ACCIP method is a promising technique to improve the bearing pressure of ultrahigh pressure apparatus,and the analytical model for the ACCIP method is also reasonable.In addition,the minimum radius ratio ro/ri under randomly specified workload can be Fig.d out by the analytical model proposed in this work.展开更多
The 2 D nanomaterials have achieved the superlubrication property whatever in solid or liquid lubrication in recent years.However,whether or not the nanosheets can stably disperse in oils and smoothly enter into the a...The 2 D nanomaterials have achieved the superlubrication property whatever in solid or liquid lubrication in recent years.However,whether or not the nanosheets can stably disperse in oils and smoothly enter into the asperity of friction pairs is crucial for exerting the function of antifriction.The structure of 2 D QDs is desirable for addressing these issues due to its smaller 3 D size.In this study,we developed a facile preparation process for WS_(2) QDs with uniform 2 nm size from nanosheets via hydrothermal-assisted grinding approach.The structure of the as-obtained WS_(2) QDs was determined by a series of characterizations.The results showed that the as-obtained WS_(2) QDs exhibited the typical spectrum features of nanosized quantum dot.The results of the tribological performance in grease verified that the average friction coefficient(ACOFs) and wear volume(AWVs) were decreased by 7.89% and 63.90%relative to grease,respectively,exhibiting a preferable friction reducing and wear resistance.展开更多
The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation fo...The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation for few-layer BNNSs.Taking advantage of the advantages of swift heating of microwave and ultra low temperature vaporization of liquid nitrogen,bulk h-BN was high-efficiently exfoliated into fewlayer BNNSs.The as-exfoliated BNNSs had a 2-6 nm thickness and approximately 7.91%yield,exhibiting scalable,facile and environment-friendly features.Furthermo re,the as-exfoliated BNNSs we re applied as additive in oil for reducing friction of oil.The COF of the BNNSs-based grease reduced by 20.10% compared to grease,and the antiwear performance decreased by 55.8% and 45.1% relative to grease and h-BN-based grease.展开更多
We have demonstrated a facile approach for the low-temperature synthesis of crystalline inorganic/metallic nanocrystal-halloysite composite nanotubes by employing the bulk controlled synthesis of inorganic/metallic na...We have demonstrated a facile approach for the low-temperature synthesis of crystalline inorganic/metallic nanocrystal-halloysite composite nanotubes by employing the bulk controlled synthesis of inorganic/metallic nanocrystals on halloysite nanotubes.The halloysite clay nanotubes can adsorb the target precursor and induce inorganic/metallic nanocrystals to grow in situ.The crystalline phase and morphology of the composite clay nanotubes is tunable.By simply tuning the acidity of the titania sol,the crystalline titania-clay nanotubes with tunable crystalline phases of anatase,a mixture of anatase and rutile or rutile are achieved.The approach is general and has been extended to synthesize the representative perovskite oxide(barium and strontium titanate)-halloysite composite nanotubes.Metallic nickel nanocrystal can also be grown on the surface of halloysite nanotubes at low temperature.The traditional thermal treatment for crystallite transformation is not required,thus intact contour of halloysite nanotubes and the crystallinity structure of halloysite nanotubes can be guaranteed.The combined properties from inorganic/metallic nanocrystal(high refractive index,high dielectric constant and catalytic ability)and the halloysite clay nanotubes are promising for applications such as photonic crystals,high-k-gate dielectrics,photocatalysis and purification.展开更多
Photo[2+2]cycloaddition of olefins is a sought-after tool for making cyclobutanes,which are the building blocks for a wide range of biologically active molecules and natural products.However,the formation of cyclobuta...Photo[2+2]cycloaddition of olefins is a sought-after tool for making cyclobutanes,which are the building blocks for a wide range of biologically active molecules and natural products.However,the formation of cyclobutane derivatives from aryl terminal olefins is problematic due to their high redox potential,and high energy in the excited state,making visible-light-absorbing photocatalyst difficult to realize either electron or energy transfer to olefins during the photocyclic addition process.Herein,we report,for the first time,the aggregationinduced photo[2+2]cycloaddition of two olefins by visible-light catalysis in homogeneous solution.An array of control experiments and spectroscopic analyses reveal that the terminal olefins tend to aggregate to form excimers/exciplexes,which possess much lower energy than their monomeric forms,and enables triplet energy transfer from excited Ir(ppy)3*to supramolecular self-assembly feasible,leading to homo and cross[2+2]photodimerization of the olefins to fabricate cyclobutanes at ambient conditions in good to excellent yields.展开更多
The branching generation during the free radical copolymerization of chain transfer monomer p-vinyl benzene sulfonyl chloride （VBSC） with styrene was investigated by a simple mathematic model. Chain transfer constan...The branching generation during the free radical copolymerization of chain transfer monomer p-vinyl benzene sulfonyl chloride （VBSC） with styrene was investigated by a simple mathematic model. Chain transfer constant of VBSC was determined to be around 0.3 by fitting the 1H-NMR monitored experimental results with a mathematic model. According to the theoretical analysis, the obtained poIy（VBSC） and its copolymers were substantiated to have a grafting-like main chain with residual pendent sulfonyl chloride groups after consuming most of the vinyl groups. The copolymerization results of VBSC with styrene at varied feed ratios demonstrated that conversion of sulfonyl chloride groups was lower than that of the monomer, which was in agreement with the theoretical results. The glass transition temperature, number average molecular weight and distribution of those obtained polymers were primarily investigated. Comparing with other chain transfer monomers, VBSC has a chain transfer constant much closer to unity therefore a more branched polymer is expected. Additionally, the branched polystyrene with residual sulfonyl chloride groups is hopefully to be further used as ATRP macro- initiators or reactive intermediates to synthesize functional polymers with complex structure.展开更多
文摘Umpolung reactions of C=X bonds(X=O,N)are valuable ways of constructing new C–C bonds,which are sometimes difficult to be constructed using traditional synthetic pathways.Classical polarity inversion of C=X bonds(X=O,N)usually requires air or moisture‐sensitive and strong reducing agents,which limit the feasibility of substrate scope.Herein we describe a photo‐induced reductive cross‐coupling reaction of aldehydes,ketones and imines with electron‐deficient arenes(aromatic nitriles)using fac‐Ir(ppy)3as a photocatalyst and diisopropylethylamine(DIPEA)as a terminal reductant under visible light irradiation.Mild conditions and high yields mean that this new polarity inversion strategy can be used with aryl‐substituted alcohols and amines.Spectroscopic studies and control experiments have demonstrated the oxidative quenching of Ir(ppy)3*by electron‐deficient arenes involved in the key step for the C–C bond formation.
文摘Objective G719 X is the most frequently seen uncommon mutation of the epidermal growth factor receptor(EGFR) gene, which is a point mutation at exon 18 with three common subtypes, G719 A/G719 C/G719 S. This study explored the clinicopathological characteristics of the G719 X mutation and investigated the efficacy of EGFR-tyrosine kinase inhibitor(TKI) treatment and chemotherapy in patients with the G719 X mutation; the survival rate after these different treatment modalities were then analyzed in order to provide evidence for clinical treatment.Methods Clinical data of 41 patients with the G719 X mutation admitted in the Beijing Chest Hospital, Capital Medical University from September 2014 to July 2018, were collected and the EGFR mutations were detected by amplification refractory mutation system-polymerase chain reaction(ARMS-PCR). The clinicopathological characteristics of the G719 X mutation were analyzed, and the relationship among the G719 X mutation, the efficacy of different treatment modalities, and the progression-free survival(PFS) was analyzed. Results Of the 41 cases, 24(58.5%) were G719 X single mutations and 17(41.5%) were compound mutations, including G719 X/S768 I, G719 X/L861 Q, G719 X/19 del, and G719 X/c-Met compound mutation. The objective response rate(ORR) of first-line EGFR-TKI therapy was 50%(6/12), the disease control rate(DCR) was 83.3%(10/12), and the median PFS(mPFS) was 9 months. After resistance to EGFR-TKI in the previous treatment, the ORR(71.4%, 5/7) and DCR(100%, 7/7) were still high following EGFR-TKIs, by an mPFS of 8 months. The ORR of chemotherapy was 33.3%(2/6), the DCR was 100%(6/6), and the mPFS was 6 months. Conclusion G719 X is an uncommon mutation of the EGFR gene and is sensitive to many EGFR-TKIs. It can be treated with the second-or third-generation EGFR-TKIs after resistance to the first-generation EGFR-TKIs. G719 X mutation also showed favorable effect to chemotherapy.
基金the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20200999),meanwhile I am also grateful to Prof.Renshu Yuan for his help.
文摘To improve the bearing pressure capacity of ultrahigh pressure apparatus,the internal autofrettaged cylinder with interlayer pressure(ACCIP)is introduced,and the analytical model for the ACCIP structure and its derivation are presented as well.Calculation showed that the ACCIP method enhance bearing pressure of the apparatus obviously;optimization results revealed that under the working pressure pw=1.07σs and different radius ratios,the ACCIP method can keep the apparatus in deformed-elastically state;And when the pw=1.07σs,the minimum radius ratio was approximate 3.29,in this case,no yielding happened.The above results demonstrate that the ACCIP method is a promising technique to improve the bearing pressure of ultrahigh pressure apparatus,and the analytical model for the ACCIP method is also reasonable.In addition,the minimum radius ratio ro/ri under randomly specified workload can be Fig.d out by the analytical model proposed in this work.
基金funded by Jiangsu Province Six Talent Peaks Project(No.2014-XCL-013)Jiangsu Industrial-academic-research Prospective Joint Project(No.BY2016069-02)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(No.PPZY2015B112)。
文摘The 2 D nanomaterials have achieved the superlubrication property whatever in solid or liquid lubrication in recent years.However,whether or not the nanosheets can stably disperse in oils and smoothly enter into the asperity of friction pairs is crucial for exerting the function of antifriction.The structure of 2 D QDs is desirable for addressing these issues due to its smaller 3 D size.In this study,we developed a facile preparation process for WS_(2) QDs with uniform 2 nm size from nanosheets via hydrothermal-assisted grinding approach.The structure of the as-obtained WS_(2) QDs was determined by a series of characterizations.The results showed that the as-obtained WS_(2) QDs exhibited the typical spectrum features of nanosized quantum dot.The results of the tribological performance in grease verified that the average friction coefficient(ACOFs) and wear volume(AWVs) were decreased by 7.89% and 63.90%relative to grease,respectively,exhibiting a preferable friction reducing and wear resistance.
基金Jiangsu Province Six Talent Peaks Project(No.2014-XCL-013)Jiangsu Industrial-academicresearch Prospective Joint Project(No.BY2016069-02)+1 种基金the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsTop-notch Academic Programs Project of Jiangsu Higher Education Institutions(No.PPZY2015B112)。
文摘The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation for few-layer BNNSs.Taking advantage of the advantages of swift heating of microwave and ultra low temperature vaporization of liquid nitrogen,bulk h-BN was high-efficiently exfoliated into fewlayer BNNSs.The as-exfoliated BNNSs had a 2-6 nm thickness and approximately 7.91%yield,exhibiting scalable,facile and environment-friendly features.Furthermo re,the as-exfoliated BNNSs we re applied as additive in oil for reducing friction of oil.The COF of the BNNSs-based grease reduced by 20.10% compared to grease,and the antiwear performance decreased by 55.8% and 45.1% relative to grease and h-BN-based grease.
基金National Natural Science Foundation of China(No.51003091)the Applied Basic Foundation of Yunnan Province(No.2013FB002)+2 种基金the Education Research Foundation of Yunnan Province(Nos.2013Y361,2010Y240)the Research Foundation of Yunnan University(No.2009B06Q)the Backbone Teacher Training Program of Yunnan University(No.XT412003).
文摘We have demonstrated a facile approach for the low-temperature synthesis of crystalline inorganic/metallic nanocrystal-halloysite composite nanotubes by employing the bulk controlled synthesis of inorganic/metallic nanocrystals on halloysite nanotubes.The halloysite clay nanotubes can adsorb the target precursor and induce inorganic/metallic nanocrystals to grow in situ.The crystalline phase and morphology of the composite clay nanotubes is tunable.By simply tuning the acidity of the titania sol,the crystalline titania-clay nanotubes with tunable crystalline phases of anatase,a mixture of anatase and rutile or rutile are achieved.The approach is general and has been extended to synthesize the representative perovskite oxide(barium and strontium titanate)-halloysite composite nanotubes.Metallic nickel nanocrystal can also be grown on the surface of halloysite nanotubes at low temperature.The traditional thermal treatment for crystallite transformation is not required,thus intact contour of halloysite nanotubes and the crystallinity structure of halloysite nanotubes can be guaranteed.The combined properties from inorganic/metallic nanocrystal(high refractive index,high dielectric constant and catalytic ability)and the halloysite clay nanotubes are promising for applications such as photonic crystals,high-k-gate dielectrics,photocatalysis and purification.
基金This work was supported financially by the Ministry of Science and Technology of China(2017YFA0206903)the National Natural Science Foundation of China(21861132004)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17000000)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(QYZDY-SSW-JSC029),and K.C.Wong Education Foundation.
文摘Photo[2+2]cycloaddition of olefins is a sought-after tool for making cyclobutanes,which are the building blocks for a wide range of biologically active molecules and natural products.However,the formation of cyclobutane derivatives from aryl terminal olefins is problematic due to their high redox potential,and high energy in the excited state,making visible-light-absorbing photocatalyst difficult to realize either electron or energy transfer to olefins during the photocyclic addition process.Herein,we report,for the first time,the aggregationinduced photo[2+2]cycloaddition of two olefins by visible-light catalysis in homogeneous solution.An array of control experiments and spectroscopic analyses reveal that the terminal olefins tend to aggregate to form excimers/exciplexes,which possess much lower energy than their monomeric forms,and enables triplet energy transfer from excited Ir(ppy)3*to supramolecular self-assembly feasible,leading to homo and cross[2+2]photodimerization of the olefins to fabricate cyclobutanes at ambient conditions in good to excellent yields.
基金supported by the National Natural Science Foundation of China(No.51003091)the Education Research Foundation of Yunnan Province(No.2010Y240)+1 种基金the Research Foundation of Yunnan University(No.2009B06Q)the Backbone Teacher Training Program of Yunnan University(No.21132014)
文摘The branching generation during the free radical copolymerization of chain transfer monomer p-vinyl benzene sulfonyl chloride （VBSC） with styrene was investigated by a simple mathematic model. Chain transfer constant of VBSC was determined to be around 0.3 by fitting the 1H-NMR monitored experimental results with a mathematic model. According to the theoretical analysis, the obtained poIy（VBSC） and its copolymers were substantiated to have a grafting-like main chain with residual pendent sulfonyl chloride groups after consuming most of the vinyl groups. The copolymerization results of VBSC with styrene at varied feed ratios demonstrated that conversion of sulfonyl chloride groups was lower than that of the monomer, which was in agreement with the theoretical results. The glass transition temperature, number average molecular weight and distribution of those obtained polymers were primarily investigated. Comparing with other chain transfer monomers, VBSC has a chain transfer constant much closer to unity therefore a more branched polymer is expected. Additionally, the branched polystyrene with residual sulfonyl chloride groups is hopefully to be further used as ATRP macro- initiators or reactive intermediates to synthesize functional polymers with complex structure.
