A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this work.The structure of grains and long peri...A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this work.The structure of grains and long period stacking ordered(LPSO)phase were characterized,and the mechanical properties uniformity was investigated.Moreover,a quantitative relationship between the microstructure and tensile yield strength was established.The results showed that the grains in the processed zone(PZ)and interfacial zone(IZ)were refined from 50μm to 3μm and 4μm,respectively,and numerous original LPSO phases were broken.In IZ,some block-shaped 18R LPSO phases were transformed into needle-like 14H LPSO phases due to stacking faults and the short-range diffusion of solute atoms.The severe shear deformation in the form of kinetic energy caused profuse stacking fault to be generated and move rapidly,greatly increasing the transformation rate of LPSO phase.After MFSP,the ultimate tensile strength,yield strength and elongation to failure of the large-scale plate were 367 MPa,305 MPa and 18.0% respectively.Grain refinement and LPSO phase strengthening were the major strengthening mechanisms for the MFSP sample.In particularly,the strength of IZ was comparable to that of PZ because the strength contribution of the 14H LPSO phase offsets the lack of grain refinement strengthening in IZ.This result opposes the widely accepted notion that IZ is a weak region in MFSP-prepared large-scale fine-grained plate.展开更多
Three-point head fixation was constructed to provide mechanical stability for single unit recording(SUR)on vestibular sensory system in living chinchilla previously.However,it is no more qualified to this work when th...Three-point head fixation was constructed to provide mechanical stability for single unit recording(SUR)on vestibular sensory system in living chinchilla previously.However,it is no more qualified to this work when the stimulation intensity becomes large because of frequent unit losing and neuron damage,which strongly implies that the mechanical stability has been broken during the stimulation.Here,we constructed a novel hea0 fixation(skull cap assistant head fixation)provided by skull cap on the basis of three-point head fixation in order to improve the mechanical stability for SUR under the stimulation with large magnitude.The large area bone connection is the feature and advantage of this improved method,which directly fixes the tested local nervous tissue and microelectrode in an intact stable system through skull cap except two ear bars and a tube face mask.Our data exhibited that skull cap assistant head fixation could significantly improve the success rate of neural response activity recording in the population of semicircular canal neurons under the stimulation with large intensity(amplitudd 00 deg/s).Based on the analysis of neural response activity and noise base-line during stimulation,our data further indicated that this method could significantly improve the mechanical stability for SUR during high-speed motion stimulation on vestibular system in living chinchilla.Skull cap assistant head fixation extends the application of SUR on vestibular neuron in linear response range and provides a solid foundation for electrophysiological research on vestibular sensory system in fhrther studies.展开更多
Background: DNA methylation plays a vital role in reproduction.Entire genome DNA methylation changes during the oestrous phase(ES) and dioestrous phase(DS) in the ovaries of Guanzhong dairy goats were investigated usi...Background: DNA methylation plays a vital role in reproduction.Entire genome DNA methylation changes during the oestrous phase(ES) and dioestrous phase(DS) in the ovaries of Guanzhong dairy goats were investigated using bisulphite sequencing to understand the molecular biological mechanisms of these goats' oestrous cycle.Results: We discovered distinct genome-wide DNA methylation patterns in ES and DS ovaries.A total of 26,910 differentially methylated regions were upregulated and 21,453 differentially methylated regions were downregulated in the ES samples compared with the DS samples(P-values ≤0.05 and fold change of methylation ratios ≥2).Differentially methylated region analysis showed hypomethylation in the gene body regions and hypermethylation in the joining region between upstream regions and gene bodies.The methylation ratios of the STAR,FGF2,FGF12,BMP5 and SMAD6 genes in the ES samples were lower than those of the DS samples(P-values≤0.05 and fold change of methylation ratios ≥2).Conversely,the methylation ratios of the EGFR,TGFBR2,IGF2 BP1 and MMD2 genes increased in the ES samples compared with the DS samples.In addition,223 differentially methylated genes were found in the GnRH signalling pathway(KO04912),ovarian steroidogenesis pathway(KO04913),oestrogen signalling pathway(KO04915),oxytocin signalling pathway(KO04921),insulin secretion pathway(KO04911) and MAPK signalling pathway(KO04010).Conclusions: This study is the first large-scale comparison of the high-resolution DNA methylation landscapes of oestrous and dioestrous ovaries from dairy goats.Previous studies and our investigations have shown that the NR5 A2,STAR,FGF2 and BMP5 genes might have potential application value in regulating caprine oestrus.展开更多
基金supported by the National Key Research and Development Program of China(2021YFB3501002)State Key Program of National Natural Science Foundation of China(5203405)+3 种基金National Natural Science Foundation of China(51974220,52104383)National Key Research and Development Program of China(2021YFB3700902)Key Research and Development Program of Shaanxi Province(2020ZDLGY13-06,2017ZDXM-GY-037)Shaanxi Province National Science Fund for Distinguished Young Scholars(2022JC-24)。
文摘A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this work.The structure of grains and long period stacking ordered(LPSO)phase were characterized,and the mechanical properties uniformity was investigated.Moreover,a quantitative relationship between the microstructure and tensile yield strength was established.The results showed that the grains in the processed zone(PZ)and interfacial zone(IZ)were refined from 50μm to 3μm and 4μm,respectively,and numerous original LPSO phases were broken.In IZ,some block-shaped 18R LPSO phases were transformed into needle-like 14H LPSO phases due to stacking faults and the short-range diffusion of solute atoms.The severe shear deformation in the form of kinetic energy caused profuse stacking fault to be generated and move rapidly,greatly increasing the transformation rate of LPSO phase.After MFSP,the ultimate tensile strength,yield strength and elongation to failure of the large-scale plate were 367 MPa,305 MPa and 18.0% respectively.Grain refinement and LPSO phase strengthening were the major strengthening mechanisms for the MFSP sample.In particularly,the strength of IZ was comparable to that of PZ because the strength contribution of the 14H LPSO phase offsets the lack of grain refinement strengthening in IZ.This result opposes the widely accepted notion that IZ is a weak region in MFSP-prepared large-scale fine-grained plate.
基金the National Natural Science Foundation of China(Nos.U1760201,52034005,51974220)the Key Research and Development Program of Shaanxi Province,China(Nos.2020ZDLGY13-06,2017ZDXM-GY-037)+1 种基金the Innovation Capacity Support Project of Shaanxi Province-Nova Program,China(No.2020KJXX-077)the Science Fund for Distinguished Young Scholars in Universities of Shaanxi Province,China。
文摘Three-point head fixation was constructed to provide mechanical stability for single unit recording(SUR)on vestibular sensory system in living chinchilla previously.However,it is no more qualified to this work when the stimulation intensity becomes large because of frequent unit losing and neuron damage,which strongly implies that the mechanical stability has been broken during the stimulation.Here,we constructed a novel hea0 fixation(skull cap assistant head fixation)provided by skull cap on the basis of three-point head fixation in order to improve the mechanical stability for SUR under the stimulation with large magnitude.The large area bone connection is the feature and advantage of this improved method,which directly fixes the tested local nervous tissue and microelectrode in an intact stable system through skull cap except two ear bars and a tube face mask.Our data exhibited that skull cap assistant head fixation could significantly improve the success rate of neural response activity recording in the population of semicircular canal neurons under the stimulation with large intensity(amplitudd 00 deg/s).Based on the analysis of neural response activity and noise base-line during stimulation,our data further indicated that this method could significantly improve the mechanical stability for SUR during high-speed motion stimulation on vestibular system in living chinchilla.Skull cap assistant head fixation extends the application of SUR on vestibular neuron in linear response range and provides a solid foundation for electrophysiological research on vestibular sensory system in fhrther studies.
基金supported by the National Natural Science Foundation of China(31601925)China postdoctoral science foundation(2016 T90954)
文摘Background: DNA methylation plays a vital role in reproduction.Entire genome DNA methylation changes during the oestrous phase(ES) and dioestrous phase(DS) in the ovaries of Guanzhong dairy goats were investigated using bisulphite sequencing to understand the molecular biological mechanisms of these goats' oestrous cycle.Results: We discovered distinct genome-wide DNA methylation patterns in ES and DS ovaries.A total of 26,910 differentially methylated regions were upregulated and 21,453 differentially methylated regions were downregulated in the ES samples compared with the DS samples(P-values ≤0.05 and fold change of methylation ratios ≥2).Differentially methylated region analysis showed hypomethylation in the gene body regions and hypermethylation in the joining region between upstream regions and gene bodies.The methylation ratios of the STAR,FGF2,FGF12,BMP5 and SMAD6 genes in the ES samples were lower than those of the DS samples(P-values≤0.05 and fold change of methylation ratios ≥2).Conversely,the methylation ratios of the EGFR,TGFBR2,IGF2 BP1 and MMD2 genes increased in the ES samples compared with the DS samples.In addition,223 differentially methylated genes were found in the GnRH signalling pathway(KO04912),ovarian steroidogenesis pathway(KO04913),oestrogen signalling pathway(KO04915),oxytocin signalling pathway(KO04921),insulin secretion pathway(KO04911) and MAPK signalling pathway(KO04010).Conclusions: This study is the first large-scale comparison of the high-resolution DNA methylation landscapes of oestrous and dioestrous ovaries from dairy goats.Previous studies and our investigations have shown that the NR5 A2,STAR,FGF2 and BMP5 genes might have potential application value in regulating caprine oestrus.
