A machinable Y TZP/LaPO 4 composite ceramic was prepared by infiltrating LaPO 4 liquid precursor into Y TZP porous ceramic. Sintered Y TZP ceramic preformed with 35% (volume fraction) open pore volume was made by...A machinable Y TZP/LaPO 4 composite ceramic was prepared by infiltrating LaPO 4 liquid precursor into Y TZP porous ceramic. Sintered Y TZP ceramic preformed with 35% (volume fraction) open pore volume was made by adding graphite (30%, volume fraction). The Y TZP/LaPO 4 composite ceramics containing different LaPO 4 contents were obtained by infiltration and pyrolysis cycles. The machinability and mechanical properties of materials were investigated. The results show that the machinable Y TZP/LaPO 4 composite ceramics containing 2 3% to 7.5% (volume fraction) LaPO 4 has good machinability as well as outstanding mechanical properties.展开更多
A high performance liquid chromatography(HPLC) method was proposed to monitor the synthesis and purification of the 1-alkyl-3-methylimidazolium ionic liquid precursors from alkylation of 1-methylimidazole with alkyl h...A high performance liquid chromatography(HPLC) method was proposed to monitor the synthesis and purification of the 1-alkyl-3-methylimidazolium ionic liquid precursors from alkylation of 1-methylimidazole with alkyl halides and determine the purity of final products.The results showed that separation of 1-methylimidazole from the precursors could be obtained under the HPLC performance conditions such as cation exchange column,acetonitrile/KH2PO4 aqueous solution and 209 nm wavelength.The content of unreacted 1-methylimidazole in the precursors could be easily calculated from their corresponding HPLC peak areas with the calibration curve of 1-methylimidazole.The retention times of the 1-alkyl-3-methylimidazolium ionic liquid precursors decreased with their increasing alkyls,and the ionic liquids with the same cation and different anions had almost the same retention times.展开更多
Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer...Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aβ generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations(A673T, A673 V, E682 K, E693 G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aβ_(1–40) and Aβ_(1–42) levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673 T mutation decreases Aβ_(42)/Aβ_(40) rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673 V, E682 K, and E693 Q mutations promote Aβ_(42)/Aβ_(40) rate by increasing levels of CTF99, Aβ_(42), Aβ_(40), and IAT, and decreasing VVIA levels. Pathogenic E693 G mutation shows no significant change in Aβ_(42)/Aβ_(40) ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aβ generation by affecting the long Aβ cleavage pathway and increasing Aβ_(42/40) rate, thereby resulting in Alzheimer's disease.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered widespread interest in the scientific community and industry for their exceptional physical and chemistry properties,and great potential for appli...Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered widespread interest in the scientific community and industry for their exceptional physical and chemistry properties,and great potential for applications in diverse fields including(opto)electronics,electrocatalysis,and energy storage.Chemical vapor deposition(CVD)is one of the most compelling growth methods for the scalable growth of high-quality 2D TMDs.However,the conventional CVD process for synthesis of 2D TMDs still encounters significant challenges,primarily attributed to the high melting point of precursor powders,and achieving a uniform distribution of precursor atmosphere on the substrate to obtain controllable smaple domains is difficult.The spin-coating precursor mediated chemical vapor deposition(SCVD)strategy provides refinement over traditional methods by eliminating the use of solid precursors and ensuring a more clean and uniform distribution of the growth material on the substrate.Additionally,the SCVD process allows fine-tuning of material thickness and purity by manipulating solution composition,concentration,and the spin coating process.This Review presents a comprehensive summary of recent advances in controllable growth of 2D TMDs with a SCVD strategy.First,a series of various liquid precursors,additives,source supply methods,and substrate engineering strategies for preparing atomically thin TMDs by SCVD are introduced.Then,2D TMDs heterostructures and novel doped TMDs fabricated through the SCVD method are discussed.Finally,the current challenges and perspectives to synthesize 2D TMDs using SCVD are discussed.展开更多
文摘A machinable Y TZP/LaPO 4 composite ceramic was prepared by infiltrating LaPO 4 liquid precursor into Y TZP porous ceramic. Sintered Y TZP ceramic preformed with 35% (volume fraction) open pore volume was made by adding graphite (30%, volume fraction). The Y TZP/LaPO 4 composite ceramics containing different LaPO 4 contents were obtained by infiltration and pyrolysis cycles. The machinability and mechanical properties of materials were investigated. The results show that the machinable Y TZP/LaPO 4 composite ceramics containing 2 3% to 7.5% (volume fraction) LaPO 4 has good machinability as well as outstanding mechanical properties.
文摘A high performance liquid chromatography(HPLC) method was proposed to monitor the synthesis and purification of the 1-alkyl-3-methylimidazolium ionic liquid precursors from alkylation of 1-methylimidazole with alkyl halides and determine the purity of final products.The results showed that separation of 1-methylimidazole from the precursors could be obtained under the HPLC performance conditions such as cation exchange column,acetonitrile/KH2PO4 aqueous solution and 209 nm wavelength.The content of unreacted 1-methylimidazole in the precursors could be easily calculated from their corresponding HPLC peak areas with the calibration curve of 1-methylimidazole.The retention times of the 1-alkyl-3-methylimidazolium ionic liquid precursors decreased with their increasing alkyls,and the ionic liquids with the same cation and different anions had almost the same retention times.
基金funded by the National Natural Science Foundation of China,No.81671268(to HQ)partially supported by a grant from the Ministry of Science and Technology of China,No.2013YQ03059514(to HQ)a grant from Key Laboratory for Neurodegenerative Disease of Ministry of Education of China,No.2015SJBX05(to HQ),2015SJZS01(to HQ)
文摘Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aβ generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations(A673T, A673 V, E682 K, E693 G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aβ_(1–40) and Aβ_(1–42) levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673 T mutation decreases Aβ_(42)/Aβ_(40) rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673 V, E682 K, and E693 Q mutations promote Aβ_(42)/Aβ_(40) rate by increasing levels of CTF99, Aβ_(42), Aβ_(40), and IAT, and decreasing VVIA levels. Pathogenic E693 G mutation shows no significant change in Aβ_(42)/Aβ_(40) ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aβ generation by affecting the long Aβ cleavage pathway and increasing Aβ_(42/40) rate, thereby resulting in Alzheimer's disease.
基金We acknowledge the support from the National Key R&D Program of the Ministry of Science and Technology of China(No.2022YFA1203801)the National Natural Science Foundation of China(grant numbers 51991340,51991343,52221001,62205055)+1 种基金the Hunan Key R&D Program Project(No.2022GK2005)Natural Science Foundation of Jiangsu Province(BK20220860).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered widespread interest in the scientific community and industry for their exceptional physical and chemistry properties,and great potential for applications in diverse fields including(opto)electronics,electrocatalysis,and energy storage.Chemical vapor deposition(CVD)is one of the most compelling growth methods for the scalable growth of high-quality 2D TMDs.However,the conventional CVD process for synthesis of 2D TMDs still encounters significant challenges,primarily attributed to the high melting point of precursor powders,and achieving a uniform distribution of precursor atmosphere on the substrate to obtain controllable smaple domains is difficult.The spin-coating precursor mediated chemical vapor deposition(SCVD)strategy provides refinement over traditional methods by eliminating the use of solid precursors and ensuring a more clean and uniform distribution of the growth material on the substrate.Additionally,the SCVD process allows fine-tuning of material thickness and purity by manipulating solution composition,concentration,and the spin coating process.This Review presents a comprehensive summary of recent advances in controllable growth of 2D TMDs with a SCVD strategy.First,a series of various liquid precursors,additives,source supply methods,and substrate engineering strategies for preparing atomically thin TMDs by SCVD are introduced.Then,2D TMDs heterostructures and novel doped TMDs fabricated through the SCVD method are discussed.Finally,the current challenges and perspectives to synthesize 2D TMDs using SCVD are discussed.
