SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant dispari...SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.展开更多
Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and ...Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface.The structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues.This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants.The applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and compared.Furthermore,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail.Finally,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented.展开更多
Synaptic dysfunction and abnormal processing of amyloid precursor protein(APP) are early pathological features in Alzheimer’s disease(AD). Recently, noncoding RNAs such as micro RNAs(mi RNAs) and circular RNAs(circ R...Synaptic dysfunction and abnormal processing of amyloid precursor protein(APP) are early pathological features in Alzheimer’s disease(AD). Recently, noncoding RNAs such as micro RNAs(mi RNAs) and circular RNAs(circ RNAs) have been reported to contribute to the pathogenesis of AD. We found an age-dependent elevation of mi R-138 in APP/PS1(presenilin-1) mice. Mi R-138 inhibited the expression of ADAM10 [a disintegrin and metalloproteinase domain-containing protein 10], promoted amyloid beta(Ab) production, and induced synaptic and learning/memory deficits in APP/PS1 mice, while its suppression alleviated the AD-like phenotype in these mice. Overexpression of sirtuin 1(Sirt1), a target of mi R-138, ameliorated the mi R-138-induced inhibition of ADAM10 and elevation of Ab in vitro. The circ RNA HDAC9(circ HDAC9) was predicted to contain a mi R-138 binding site in several databases. Its expression was inversely correlated with mi R-138 in both Ab-oligomertreated N2 a cells and APP/PS1 mice, and it co-localized with mi R-138 in the cytoplasm of N2 a cells. Circ HDAC9 acted as a mi R-138 sponge, decreasing mi R-138 expression, and reversing the Sirt1 suppression and excessive Ab production induced by mi R-138 in vitro. Moreover,circ HDAC9 was decreased in the serum of both AD patients and individuals with mild cognitive impairment.These results suggest that the circ HDAC9/mi R-138/Sirt1 pathway mediates synaptic function and APP processing in AD, providing a potential therapeutic target for its treatment.展开更多
Objective： Very low density lipoprotein receptor （VLDLR） has been considered as a multiple function receptor due to binding numerous ligands, causing endocytosis and regulating cellular signaling. Our group previou...Objective： Very low density lipoprotein receptor （VLDLR） has been considered as a multiple function receptor due to binding numerous ligands, causing endocytosis and regulating cellular signaling. Our group previously reported that type II VLDLR overexpression in breast cancer tissues. The purpose of this study is to characterize type II VLDLR activities during cell migration using breast cancer cell lines. Methods： Western blotting was used to test protein expression. Cell migration was analyzed by Scratch wound assay. The mRNA expression was tested by realtime-PCR. Reporter assay was to test the transcription activity. Results： Scratch wound and Report assay indicated up-regulated VLDLR II expression promotes cell migration via activating Wnt/β-catenin pathway. The target genes such as VEGF, MMP2 and MMP7 were upregulated in VLDLR II overexpressed cells. On the contrary, cells treated with TFPI had an inhibition effect of cell migration response to down-regulation of VLDLR Ⅱ. Conclusion： Type Ⅱ VLDLR conferred a migration and invasion advantage by activating Wnt/β- catenin pathway, then up-regulating VEGF, MMP2 and MMP7 in breast cancer cells.展开更多
Background Synaptic degeneration occurs in the early stage of Alzheimer’s disease(AD)before devastating symptoms,strongly correlated with cognitive decline.Circular RNAs(circRNAs)are abundantly enriched in neural tis...Background Synaptic degeneration occurs in the early stage of Alzheimer’s disease(AD)before devastating symptoms,strongly correlated with cognitive decline.Circular RNAs(circRNAs)are abundantly enriched in neural tissues,and aberrant expression of circRNAs precedes AD symptoms,significantly correlated with clinical dementia severity.However,the direct relationship between circRNA dysregulation and synaptic impairment in the early stage of AD remains poorly understood.Methods Hippocampal whole-transcriptome sequencing was performed to identify dysregulated circRNAs and miRNAs in 4-month-old wild-type and APP/PS1 mice.RNA antisense purification and mass spectrometry were utilized to unveil interactions between circRIMS2 and methyltransferase 3,N6-adenosine-methyltransferase complex catalytic subunit(METTL3).The roles of circRIMS2/miR-3968 in synaptic targeting of UBE2K-mediated ubiquitination of GluN2B subunit of NMDA receptor were evaluated via numerous lentiviruses followed by morphological staining,co-immunoprecipitation and behavioral testing.Further,a membrane-permeable peptide was used to block the ubiquitination of K1082 on GluN2B in AD mice.Results circRIMS2 was significantly upregulated in 4-month-old APP/PS1 mice,which was mediated by METTL3-dependent N6-methyladenosine(m6A)modification.Overexpression of circRIMS2 led to synaptic and memory impairments in 4-month-old C57BL/6 mice.MiR-3968/UBE2K was validated as the downstream of circRIMS2.Elevated UBE2K induced synaptic dysfunction of AD through ubiquitinating K1082 on GluN2B.Silencing METTL3 or blocking the ubiquitination of K1082 on GluN2B with a short membrane-permeable peptide remarkably rescued synaptic dysfunction in AD mice.Conclusions In conclusion,our study demonstrated that m6A-modified circRIMS2 mediates the synaptic and memory impairments in AD by activating the UBE2K-dependent ubiquitination and degradation of GluN2B via sponging miR-3968,providing novel therapeutic strategies for AD.展开更多
This paper carries out studies about LA-ICPMS U–Pb dating and Hf isotopic compositional analysis for detrital zircons in two metasedimentary samples that were taken from the Zhaochigou Formation-complex in the Helan ...This paper carries out studies about LA-ICPMS U–Pb dating and Hf isotopic compositional analysis for detrital zircons in two metasedimentary samples that were taken from the Zhaochigou Formation-complex in the Helan Mountain.The results show that the Zhaochigou Formation-complex formed*1.96 Ga,and it is a part of the Khondalite Series that is widespread in the North China Craton(NCC).The age spectrum of the detrital zircons indicates that the Zhaochigou Formation-complex shared the same provenance with the eastern edge of the Khondalite Series.Products of ancient magmatic activities within the Khondalite Belt may be the major source for the sedimentary materials that formed the Khondalite Series.Our age-dating results suggest that the Khondalite Series in the NCC may have experienced two stages of metamorphism,as the early stage occurred during 1.96–1.95 Ga,and the later stage occurred at about 1.87 Ga.The Hfisotopic data indicate that the Western Block of the NCC endured a stage of crustal growth at 2.5–2.3 Ga.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52475480,51805334)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515030249,2023A1515110059)Shenzhen Science and Technology Program(Grant No.GJHZ20220913144212023).
文摘SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.
基金Supported by National Natural Science Foundation of China (Grant Nos.52235011,51905352)Shenzhen Municipal Excellent Science and Technology Creative Talent Training Program (Grant No.RCBS20210609103819021)+1 种基金Guangdong Provincial Basic and Applied Basic Research Foundation (Grant No.2023B1515120086)Shenzhen Municipal Science and Technology Planning Project (Grant No.CJGJZD20230724093600001)。
文摘Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface.The structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues.This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants.The applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and compared.Furthermore,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail.Finally,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented.
基金supported by the National Natural Science Foundation of China (81500925)
文摘Synaptic dysfunction and abnormal processing of amyloid precursor protein(APP) are early pathological features in Alzheimer’s disease(AD). Recently, noncoding RNAs such as micro RNAs(mi RNAs) and circular RNAs(circ RNAs) have been reported to contribute to the pathogenesis of AD. We found an age-dependent elevation of mi R-138 in APP/PS1(presenilin-1) mice. Mi R-138 inhibited the expression of ADAM10 [a disintegrin and metalloproteinase domain-containing protein 10], promoted amyloid beta(Ab) production, and induced synaptic and learning/memory deficits in APP/PS1 mice, while its suppression alleviated the AD-like phenotype in these mice. Overexpression of sirtuin 1(Sirt1), a target of mi R-138, ameliorated the mi R-138-induced inhibition of ADAM10 and elevation of Ab in vitro. The circ RNA HDAC9(circ HDAC9) was predicted to contain a mi R-138 binding site in several databases. Its expression was inversely correlated with mi R-138 in both Ab-oligomertreated N2 a cells and APP/PS1 mice, and it co-localized with mi R-138 in the cytoplasm of N2 a cells. Circ HDAC9 acted as a mi R-138 sponge, decreasing mi R-138 expression, and reversing the Sirt1 suppression and excessive Ab production induced by mi R-138 in vitro. Moreover,circ HDAC9 was decreased in the serum of both AD patients and individuals with mild cognitive impairment.These results suggest that the circ HDAC9/mi R-138/Sirt1 pathway mediates synaptic function and APP processing in AD, providing a potential therapeutic target for its treatment.
文摘Objective： Very low density lipoprotein receptor （VLDLR） has been considered as a multiple function receptor due to binding numerous ligands, causing endocytosis and regulating cellular signaling. Our group previously reported that type II VLDLR overexpression in breast cancer tissues. The purpose of this study is to characterize type II VLDLR activities during cell migration using breast cancer cell lines. Methods： Western blotting was used to test protein expression. Cell migration was analyzed by Scratch wound assay. The mRNA expression was tested by realtime-PCR. Reporter assay was to test the transcription activity. Results： Scratch wound and Report assay indicated up-regulated VLDLR II expression promotes cell migration via activating Wnt/β-catenin pathway. The target genes such as VEGF, MMP2 and MMP7 were upregulated in VLDLR II overexpressed cells. On the contrary, cells treated with TFPI had an inhibition effect of cell migration response to down-regulation of VLDLR Ⅱ. Conclusion： Type Ⅱ VLDLR conferred a migration and invasion advantage by activating Wnt/β- catenin pathway, then up-regulating VEGF, MMP2 and MMP7 in breast cancer cells.
基金supported by the National Natural Science Foundation of China(82372337,81500925 to Xiong Wang,81801062 to Xiaoguang Li)Tongji Hospital(HUST)Foundation for Excellent Young Scientist(2020YQ01-11 to Xiong Wang)the Natural Science Foundation of Hubei Province(2022CFB150 to Huijun Li).
文摘Background Synaptic degeneration occurs in the early stage of Alzheimer’s disease(AD)before devastating symptoms,strongly correlated with cognitive decline.Circular RNAs(circRNAs)are abundantly enriched in neural tissues,and aberrant expression of circRNAs precedes AD symptoms,significantly correlated with clinical dementia severity.However,the direct relationship between circRNA dysregulation and synaptic impairment in the early stage of AD remains poorly understood.Methods Hippocampal whole-transcriptome sequencing was performed to identify dysregulated circRNAs and miRNAs in 4-month-old wild-type and APP/PS1 mice.RNA antisense purification and mass spectrometry were utilized to unveil interactions between circRIMS2 and methyltransferase 3,N6-adenosine-methyltransferase complex catalytic subunit(METTL3).The roles of circRIMS2/miR-3968 in synaptic targeting of UBE2K-mediated ubiquitination of GluN2B subunit of NMDA receptor were evaluated via numerous lentiviruses followed by morphological staining,co-immunoprecipitation and behavioral testing.Further,a membrane-permeable peptide was used to block the ubiquitination of K1082 on GluN2B in AD mice.Results circRIMS2 was significantly upregulated in 4-month-old APP/PS1 mice,which was mediated by METTL3-dependent N6-methyladenosine(m6A)modification.Overexpression of circRIMS2 led to synaptic and memory impairments in 4-month-old C57BL/6 mice.MiR-3968/UBE2K was validated as the downstream of circRIMS2.Elevated UBE2K induced synaptic dysfunction of AD through ubiquitinating K1082 on GluN2B.Silencing METTL3 or blocking the ubiquitination of K1082 on GluN2B with a short membrane-permeable peptide remarkably rescued synaptic dysfunction in AD mice.Conclusions In conclusion,our study demonstrated that m6A-modified circRIMS2 mediates the synaptic and memory impairments in AD by activating the UBE2K-dependent ubiquitination and degradation of GluN2B via sponging miR-3968,providing novel therapeutic strategies for AD.
基金supported by the Key Project of National Natural Science Foundation of China(41230206)the project of China Geological Survey(1212011120552)
文摘This paper carries out studies about LA-ICPMS U–Pb dating and Hf isotopic compositional analysis for detrital zircons in two metasedimentary samples that were taken from the Zhaochigou Formation-complex in the Helan Mountain.The results show that the Zhaochigou Formation-complex formed*1.96 Ga,and it is a part of the Khondalite Series that is widespread in the North China Craton(NCC).The age spectrum of the detrital zircons indicates that the Zhaochigou Formation-complex shared the same provenance with the eastern edge of the Khondalite Series.Products of ancient magmatic activities within the Khondalite Belt may be the major source for the sedimentary materials that formed the Khondalite Series.Our age-dating results suggest that the Khondalite Series in the NCC may have experienced two stages of metamorphism,as the early stage occurred during 1.96–1.95 Ga,and the later stage occurred at about 1.87 Ga.The Hfisotopic data indicate that the Western Block of the NCC endured a stage of crustal growth at 2.5–2.3 Ga.
