Mg−Al layered double hydroxides(LDHs),produced on cast Mg−xCa(x=0.5,0.8,2.0,wt.%)alloys by an in-situ growth method,showed good corrosion resistance compared to the bare magnesium substrate.The influence mechanism of ...Mg−Al layered double hydroxides(LDHs),produced on cast Mg−xCa(x=0.5,0.8,2.0,wt.%)alloys by an in-situ growth method,showed good corrosion resistance compared to the bare magnesium substrate.The influence mechanism of the second phase(Mg_(2)Ca)on LDHs production was investigated.Increasing Ca content increased the amount of Mg_(2)Ca,decreasing the grain size and the corrosion rate of the alloys.The increased amount of the second phase particles and the grain refinement promoted the growth of LDHs,and thus led to the decreasing of corrosion rate of the Mg−xCa alloys with LDHs.A higher Mg_(2)Ca amount resulted in forming fluffy LDHs.Due to the dual effects of the second phase(Mg_(2)Ca)for LDHs growth and microgalvanic corrosion,LDHs/Mg−0.8Ca showed the lowest corrosion rate.展开更多
The synchronous enhancement mechanism of the mechanical properties and degradation rate of as-extruded Mg−xEr−1.6Ni alloys(x=17,12,and 9.5,wt.%)was investigated by controlling Er content.Results indicate that,as the E...The synchronous enhancement mechanism of the mechanical properties and degradation rate of as-extruded Mg−xEr−1.6Ni alloys(x=17,12,and 9.5,wt.%)was investigated by controlling Er content.Results indicate that,as the Er content decreases,the overall content and the distribution of secondary phases did not change evidently,while the type of the secondary phases changed from single long-period stacking ordered(LPSO)phase to coexistence of the LPSO phase andγ'phase.Notably,the tensile yield strength(TYS)and degradation rate of the Mg alloy with a lower Er content(i.e.,Mg−9.5Er−1.6Ni alloy)are increased by 22.3%and 51.5%respectively compared to those of the Mg alloy with a higher Er content(i.e.,Mg−17Er−1.6Ni).The enhancement of mechanical properties of the Mg alloy with a lower Er content is attributed to the formation ofγ'phase,which can refine the grain size by inhibiting dynamic recrystallization,leading to enhanced TYS by secondary phase and grain boundary strengthening.Meanwhile,finer grains and theγ'phase also provide more corrosion sites and inhibit the formation of corrosion-resistant Er_(2)O_(3)film,thereby accelerating the corrosion of Mg alloy.展开更多
In order to study the eff ect of friction stir welding(FSW)on corrosion resistance of Al–Cu–Li alloy AA2099-T8,the microstructure and microhardness of FSW joints were characterized,and then,the corrosion behavior of...In order to study the eff ect of friction stir welding(FSW)on corrosion resistance of Al–Cu–Li alloy AA2099-T8,the microstructure and microhardness of FSW joints were characterized,and then,the corrosion behavior of the FSW joints was investigated by the immersion and potentiodynamic polarization tests in a 3.5%NaCl solution at room temperature.It is indicated that the alloy was softened by FSW,with the lowest hardness appearing at the boundary between the nugget zone and the thermo-mechanically aff ected zone.When exposed to the NaCl solution,the FSW joint was characterized by shallow pits and was free of severe localized corrosion,probably due to dissolution of T 1(A 2 CuLi)phase in the FSW joint.It is suggested that further work should be carried out to evaluate the galvanic coupling eff ect between the FSW joint and the base metal,as well as the stress corrosion cracking resistance of the FSW joint.展开更多
Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting.Currently, four bioorthogonal pairs as targeting tools, including (strept...Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting.Currently, four bioorthogonal pairs as targeting tools, including (strept)avidin/biotin, antibody/antigen, oligonucleotide hybridization and IEDDA tools, have been developed and applied in targeted delivery.Nevertheless, all of these tools still suffer from some limitations, such as difficult modification, biochemical fragility and larger molecular weight for biological association tools, as well as chemical instability for IEDDA tools.Synthetic host-vip pairs with relatively small molecular sizes not only possess strong chemical stability, but also have the features of fast conjugation rate, tunable binding affinity , easy modification, and high chemo-selectivity.Consequently, they can be used as a novel non-covalent bioorthogonal tool for pre-targeting.In order to further promote the development of host-vip pairs as novel bioorthogonal tools for pre-targeted delivery, we firstly calculate their conversion rate to make researcher aware of their unique advantages;next, we summarize the recent research progress in this area.The future perspectives and limitations of these unique tools will be discussed.This review will provide a systemic overview of the development of synthetic host-vip pairs as novel bioorthogonal tools for pre-targeting, and may serve as a “go for” resort for researchers who are interested in searching for new synthetic tools to improve pre-targeting.展开更多
Bioconjugation methods offer very important tools in studying biological systems.Synthetic host-vip pairs provide an alternative and complementary conjugation method to bioorthogonal reactions and biological associa...Bioconjugation methods offer very important tools in studying biological systems.Synthetic host-vip pairs provide an alternative and complementary conjugation method to bioorthogonal reactions and biological association pairs.Nevertheless,macrocyclic hosts that can be used for in situ capture are limited and often rely on extremely high binding affinities.Herein,we report an alternative bioorthogonal host-vip pair that relies on highly selective molecular recognition in water.The host,namely amide naphthotube,possesses a biomimetic cavity with inward-directing hydrogen bonding sites and shows selective and strong binding to the vip(2-phenyl pyrimidine)even in biological media.Through anchoring the tetraphenyl ethylene-modi fied hosts to cell surfaces,the bioorthogonal host-vip pair can be applied in cell surface recognition,cell-cell interactions,and tissue imaging in mice.The bioorthogonality is originated from the high binding selectivity of the biomimetic macrocyclic host,which is different from other known host-vip pairs that have been applied in biological systems.This research provides a new noncovalent bioconjugation tool and a new concept for designing bioorthogonal host-vip pairs for biological applications.展开更多
Molecular recognition in water is the basis of numerous biological functions.The key for efficient and selective recognition of an organic drug molecule is to bind both its polar and nonpolar groups.This is achieved b...Molecular recognition in water is the basis of numerous biological functions.The key for efficient and selective recognition of an organic drug molecule is to bind both its polar and nonpolar groups.This is achieved by bioreceptors for which specific noncovalent interactions are efficiently used in a hydrophobic pocket.In contrast,most synthetic receptors cannot efficiently bind the neutral,polar groups of drug molecules and,thus,often exhibit poor binding selectivity and affinity.In this research,we report a systematic study on the binding behaviors of three types of macrocyclic hosts(amide naphthotubes,cucurbit[7]uril,andβ-cyclodextrin)to 18 model compounds and 13 drug molecules.Our results show that the high desolvation penalty of polar groups of vips is the reason for the relatively low binding affinity of cucurbit[7]uril andβ-cyclodextrin.However,amide naphthotubes with a biomimetic cavity bind efficiently and selectively to organic vips through hydrophobic effects and hydrogen bonding.Drug molecules with multiple polar groups can be better accommodated by these naphthotubes.The anti-configured naphthotube show good biocompatibility according to preliminary cell experiments and is capable of enhancing the water solubility of two poorly soluble drug molecules.Therefore,they may have practical applications in pharmaceutical sciences.展开更多
基金supported by the National Natural Science Foundation of China(No.51971040)the Fundamental Research Funds for the Central Universities,China(No.2020CDJQY-A007)+1 种基金China Postdoctoral Science Foundation(Nos.2017M620410,2018T110942)the Chongqing Postdoctoral Scientific Research Foundation,China(No.Xm2017010).
文摘Mg−Al layered double hydroxides(LDHs),produced on cast Mg−xCa(x=0.5,0.8,2.0,wt.%)alloys by an in-situ growth method,showed good corrosion resistance compared to the bare magnesium substrate.The influence mechanism of the second phase(Mg_(2)Ca)on LDHs production was investigated.Increasing Ca content increased the amount of Mg_(2)Ca,decreasing the grain size and the corrosion rate of the alloys.The increased amount of the second phase particles and the grain refinement promoted the growth of LDHs,and thus led to the decreasing of corrosion rate of the Mg−xCa alloys with LDHs.A higher Mg_(2)Ca amount resulted in forming fluffy LDHs.Due to the dual effects of the second phase(Mg_(2)Ca)for LDHs growth and microgalvanic corrosion,LDHs/Mg−0.8Ca showed the lowest corrosion rate.
基金supported by the National Key Research and Development Program of China(No.2021YFB3701100)the Natural National Science Foundation of China(Nos.U20A20234,51874062)+1 种基金the Chongqing Foundation and Advanced Research Project,China(No.cstc2019jcyj-zdxmX0010)the Natural Science Foundation of Chongqing,China(No.CSTB2022NSCQ-BHX0029).
文摘The synchronous enhancement mechanism of the mechanical properties and degradation rate of as-extruded Mg−xEr−1.6Ni alloys(x=17,12,and 9.5,wt.%)was investigated by controlling Er content.Results indicate that,as the Er content decreases,the overall content and the distribution of secondary phases did not change evidently,while the type of the secondary phases changed from single long-period stacking ordered(LPSO)phase to coexistence of the LPSO phase andγ'phase.Notably,the tensile yield strength(TYS)and degradation rate of the Mg alloy with a lower Er content(i.e.,Mg−9.5Er−1.6Ni alloy)are increased by 22.3%and 51.5%respectively compared to those of the Mg alloy with a higher Er content(i.e.,Mg−17Er−1.6Ni).The enhancement of mechanical properties of the Mg alloy with a lower Er content is attributed to the formation ofγ'phase,which can refine the grain size by inhibiting dynamic recrystallization,leading to enhanced TYS by secondary phase and grain boundary strengthening.Meanwhile,finer grains and theγ'phase also provide more corrosion sites and inhibit the formation of corrosion-resistant Er_(2)O_(3)film,thereby accelerating the corrosion of Mg alloy.
基金supported by Chongqing Talent Plan:Leading Talents in Innovation and Entrepreneurship,China(No.CQYC201903051)University Innovation Research Group of Chongqing,China(No.CXQT20023)+4 种基金Qingnian Project of Science and Technology Research Program of Chongqing Municipal Education Commission,China(No.KJQN202001106)China Postdoctoral Science Foundation(No.2021M700556)Natural Science Foundation of Chongqing,China(No.cstc2021jcyj-bsh X0114)Natural Science Foundation of China(Nos.U20A20234,51874062)Chongqing Foundation and Advanced Research Project,China(No.cstc2019jcyj-zdxm X0010)。
基金the financial supports from the University Innovation Research Group of Chongqing,China(No.CXQT20023)the Graduate Student Innovation Program of Chongqing University of Technology,China(No.CLGYCX20203006)。
基金supported by the Chongqing Talent Plan:Leading Talents in Innovation and Entrepreneurship,China (No.CQYC201903051)the University Innovation Research Group of Chongqing,China (No.CXQT20023)+2 种基金the Chongqing Natural Science Foundation,China (No.CSTB2022NSCQ-MSX0326)the National Natural Science Foundation of China (No.51871038)the Basic Research and Frontier Exploration Project of Chongqing Science and Technology Commission,China (No.cstc2021ycjh-bgzxm0173).
基金the Basic and Frontier Research Program of Chongqing(Grant Nos.cstc2016jcyjA0490 and cstc2017jcyjAX0285).
文摘In order to study the eff ect of friction stir welding(FSW)on corrosion resistance of Al–Cu–Li alloy AA2099-T8,the microstructure and microhardness of FSW joints were characterized,and then,the corrosion behavior of the FSW joints was investigated by the immersion and potentiodynamic polarization tests in a 3.5%NaCl solution at room temperature.It is indicated that the alloy was softened by FSW,with the lowest hardness appearing at the boundary between the nugget zone and the thermo-mechanically aff ected zone.When exposed to the NaCl solution,the FSW joint was characterized by shallow pits and was free of severe localized corrosion,probably due to dissolution of T 1(A 2 CuLi)phase in the FSW joint.It is suggested that further work should be carried out to evaluate the galvanic coupling eff ect between the FSW joint and the base metal,as well as the stress corrosion cracking resistance of the FSW joint.
基金supported by the Science and Technology Program of Guangzhou(No.202103000089)the National Natural Science Foundation of China(Nos.22271323 and 22071275)+2 种基金the Innovation Team Project of Universities in Guangdong Province(No.2020KCXTD009)the Scientific and Technological Innovation Leading Talent Project of Zhongshan City(No.LJ2021009)the Key Projects of Social Welfare and Basic Research of Zhongshan City(No.2021B2012).
文摘Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting.Currently, four bioorthogonal pairs as targeting tools, including (strept)avidin/biotin, antibody/antigen, oligonucleotide hybridization and IEDDA tools, have been developed and applied in targeted delivery.Nevertheless, all of these tools still suffer from some limitations, such as difficult modification, biochemical fragility and larger molecular weight for biological association tools, as well as chemical instability for IEDDA tools.Synthetic host-vip pairs with relatively small molecular sizes not only possess strong chemical stability, but also have the features of fast conjugation rate, tunable binding affinity , easy modification, and high chemo-selectivity.Consequently, they can be used as a novel non-covalent bioorthogonal tool for pre-targeting.In order to further promote the development of host-vip pairs as novel bioorthogonal tools for pre-targeted delivery, we firstly calculate their conversion rate to make researcher aware of their unique advantages;next, we summarize the recent research progress in this area.The future perspectives and limitations of these unique tools will be discussed.This review will provide a systemic overview of the development of synthetic host-vip pairs as novel bioorthogonal tools for pre-targeting, and may serve as a “go for” resort for researchers who are interested in searching for new synthetic tools to improve pre-targeting.
基金financially supported by National Natural Science Foundation of China(nos.21772083 and 21822104)the Shenzhen Special Funds(no.JCYJ20180504165810828)+4 种基金the Guangdong Provincial Key Laboratory of Catalysis(no.2020B121201002)the University of Macao(no.MYRG2019-00059-ICMS)the Shenzhen“Pengcheng Scholar”ProgramGuangdong High-Level Personnel of Special Support Program(no.2019TX05C157)SUSTech-CRF for the technical support.
文摘Bioconjugation methods offer very important tools in studying biological systems.Synthetic host-vip pairs provide an alternative and complementary conjugation method to bioorthogonal reactions and biological association pairs.Nevertheless,macrocyclic hosts that can be used for in situ capture are limited and often rely on extremely high binding affinities.Herein,we report an alternative bioorthogonal host-vip pair that relies on highly selective molecular recognition in water.The host,namely amide naphthotube,possesses a biomimetic cavity with inward-directing hydrogen bonding sites and shows selective and strong binding to the vip(2-phenyl pyrimidine)even in biological media.Through anchoring the tetraphenyl ethylene-modi fied hosts to cell surfaces,the bioorthogonal host-vip pair can be applied in cell surface recognition,cell-cell interactions,and tissue imaging in mice.The bioorthogonality is originated from the high binding selectivity of the biomimetic macrocyclic host,which is different from other known host-vip pairs that have been applied in biological systems.This research provides a new noncovalent bioconjugation tool and a new concept for designing bioorthogonal host-vip pairs for biological applications.
基金This research was financially supported by the National Natural Science Foundation of China(nos.21772083 and 21822104)the Shenzhen Special Funds(KQJSCX20170728162528382 and JCYJ20180504165810828)+3 种基金the Guangdong Provincial Key Laboratory of Catalysis(2020B121201002)the China Postdoctoral Science Foundation(grant no.2019M652183)the University of Macao(MYRG2019-00059-ICMS)the Shenzhen Nobel Prize Scientists Laboratory Project(C17213101)。
文摘Molecular recognition in water is the basis of numerous biological functions.The key for efficient and selective recognition of an organic drug molecule is to bind both its polar and nonpolar groups.This is achieved by bioreceptors for which specific noncovalent interactions are efficiently used in a hydrophobic pocket.In contrast,most synthetic receptors cannot efficiently bind the neutral,polar groups of drug molecules and,thus,often exhibit poor binding selectivity and affinity.In this research,we report a systematic study on the binding behaviors of three types of macrocyclic hosts(amide naphthotubes,cucurbit[7]uril,andβ-cyclodextrin)to 18 model compounds and 13 drug molecules.Our results show that the high desolvation penalty of polar groups of vips is the reason for the relatively low binding affinity of cucurbit[7]uril andβ-cyclodextrin.However,amide naphthotubes with a biomimetic cavity bind efficiently and selectively to organic vips through hydrophobic effects and hydrogen bonding.Drug molecules with multiple polar groups can be better accommodated by these naphthotubes.The anti-configured naphthotube show good biocompatibility according to preliminary cell experiments and is capable of enhancing the water solubility of two poorly soluble drug molecules.Therefore,they may have practical applications in pharmaceutical sciences.
