Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk p...Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk proteins were first separated by SDS polyacrylamide gel electrophoresis.After in gels digestion and extraction,phosphorylated peptides were enriched by titanium dioxide and identified by ultra performance liquid chromatography coupled with nano electrospray ionization tandem mass spectrometry.This method ensured the identification of 20 phosphorylated peptides,including 7 phosphorylated forms of α_s1-casein,8 α_s2-casein,and 5 β-casein.Eight phosphorylated sites derived from 3 α_s1-caseins,3 α_s2-caseins,and 2 β-caseins were also identified,and localized on residues Ser^61,Ser^63 and Ser^130 in α_s1-casein;Thr^145,Ser^146 and Ser^158 in α_s2-casein;and Ser^50 and Thr^56 in β-casein.These findings provide valuable information for investigating casein phosphorylation of the bovine milk.展开更多
Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-i...Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide（LPS）, a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti（ASTM Grade 2, Grade 4 and Grade 5）. Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to p H of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions（p H 2）, which may develop in localized corrosion sites, but promoted dissolution at p H 4–7, which would be more commonly encountered physiologically.The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo.展开更多
Based on the mass action concentration theory,a novel thermodynamic analysis for the raw material ratio in the procedure of preparing Ti-6Al-4V alloy by aluminothermic reduction process is proposed in this paper,which...Based on the mass action concentration theory,a novel thermodynamic analysis for the raw material ratio in the procedure of preparing Ti-6Al-4V alloy by aluminothermic reduction process is proposed in this paper,which is originated from TiO_(2),Al particles,and V_(2)O_(5) as feedstocks,and the relevant equilibrium thermodynamics was calculated through this new method.The results show that the range of aluminum addition coefficient in raw material to experiment should be controlled within 61.5%-100%,which can significantly reduce the number of experimental groups.This method is ready to regulate the matter of excessive aluminum content in reactants for materials preparation,especially for those reactions including elements that are effortless to combine with aluminum to form the corresponding intermetallics or alloys.In addition,it can also be used in general metallurgy or material preparation process to effectively predict the composition and proportion of equilibrium components under certain conditions.展开更多
采用高压密闭消解系统,以6 mL HNO3-1 mL HF-3 mLHCl酸体系消解锰矿石,建立了电感耦合等离子体质谱法（ICP-MS）测定锰矿石中钛、钒、锶3种金属元素的方法.选择^48Ti、^51V和^88Sr为待测同位素,以钪（45 Sc）和铟（115 In）为内标校正...采用高压密闭消解系统,以6 mL HNO3-1 mL HF-3 mLHCl酸体系消解锰矿石,建立了电感耦合等离子体质谱法（ICP-MS）测定锰矿石中钛、钒、锶3种金属元素的方法.选择^48Ti、^51V和^88Sr为待测同位素,以钪（45 Sc）和铟（115 In）为内标校正了基体效应与信号漂移.钛、钒和锶校准曲线的线性相关系数均为0.999 9,检出限分别为0.12、0.003 0和0.014 ng/mL.将方法用于锰矿石实际样品分析,结果与电感耦合等离子体原子发射光谱法（ICP-AES）基本一致,相对标准偏差（RSD,n=11）不大于2.0％,加标回收率在99％～102％之间.展开更多
基金supported by an earmark fund for the National Key Basic Research Program of China(2011CB100805)
文摘Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk proteins were first separated by SDS polyacrylamide gel electrophoresis.After in gels digestion and extraction,phosphorylated peptides were enriched by titanium dioxide and identified by ultra performance liquid chromatography coupled with nano electrospray ionization tandem mass spectrometry.This method ensured the identification of 20 phosphorylated peptides,including 7 phosphorylated forms of α_s1-casein,8 α_s2-casein,and 5 β-casein.Eight phosphorylated sites derived from 3 α_s1-caseins,3 α_s2-caseins,and 2 β-caseins were also identified,and localized on residues Ser^61,Ser^63 and Ser^130 in α_s1-casein;Thr^145,Ser^146 and Ser^158 in α_s2-casein;and Ser^50 and Thr^56 in β-casein.These findings provide valuable information for investigating casein phosphorylation of the bovine milk.
基金funded in part by the University of Birminghamthe China Scholarship Councilfunded by NIHR Clinician Scientist Award NIHR/CS/010/001
文摘Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide（LPS）, a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti（ASTM Grade 2, Grade 4 and Grade 5）. Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to p H of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions（p H 2）, which may develop in localized corrosion sites, but promoted dissolution at p H 4–7, which would be more commonly encountered physiologically.The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo.
基金the National Natural Science Foundation of China(No.U1908225)the Doctoral Scientific Research Foundation of Liaocheng University (No.318052124)。
文摘Based on the mass action concentration theory,a novel thermodynamic analysis for the raw material ratio in the procedure of preparing Ti-6Al-4V alloy by aluminothermic reduction process is proposed in this paper,which is originated from TiO_(2),Al particles,and V_(2)O_(5) as feedstocks,and the relevant equilibrium thermodynamics was calculated through this new method.The results show that the range of aluminum addition coefficient in raw material to experiment should be controlled within 61.5%-100%,which can significantly reduce the number of experimental groups.This method is ready to regulate the matter of excessive aluminum content in reactants for materials preparation,especially for those reactions including elements that are effortless to combine with aluminum to form the corresponding intermetallics or alloys.In addition,it can also be used in general metallurgy or material preparation process to effectively predict the composition and proportion of equilibrium components under certain conditions.
