Resorbable bioceramics are attractive for medical applications such as bone substitution. Biochemical analysis on cells cultured on these biomaterials is vital to predict the impact of the materials in vivo and RNA ex...Resorbable bioceramics are attractive for medical applications such as bone substitution. Biochemical analysis on cells cultured on these biomaterials is vital to predict the impact of the materials in vivo and RNA extraction is an essential step in gene expression study using RT-qPCR. In this study, we describe simple modifications to the TRIzol? RNA extraction protocol widely used in biology and these allow high-yield extraction of RNA from cells on resorbable calcium phosphates. Without the modifications, RNA is trapped in the co-precipitated calcium compounds, rendering TRIzol? extraction method infeasible. Among the modifications, the use of extra TRIzol? to dilute the lysate before the RNA precipitation step is critical for extraction of RNA from porous ?-tricalcium phosphate (?-TCP) discs. We also investigate the rationale behind the undesirable precipitation so as to provide clues about the modifications required for other resorbable materials with high application potential in bone tissue engineering.展开更多
UV Tri was observed photometrically from 1999 to 2000 at the Xinglong Station of the National Astronomical Observatories, Chinese Academy of Sciences, and was also observed with Stromgren uvbyHβ filter system at the ...UV Tri was observed photometrically from 1999 to 2000 at the Xinglong Station of the National Astronomical Observatories, Chinese Academy of Sciences, and was also observed with Stromgren uvbyHβ filter system at the Sierra Nevada Observatory (Spain) in 2000. From period analyses of the data, three pulsation frequencies, 9.3299 c d-1 10.8483 cd-1 and 3.6035 cd-1 were obtained. We derived color indices: b - y = 0.215, m1 = 0.169, c1 = 0.783, and β = 2.775. With these indices and some calibrations, we obtain: Mv = 2.44, Mbol = 2.27, logL/L = 0.99, and log Teff = 3.875. Evolutionary sequences of stellar models with 1.00-2.00 solar masses, at steps of 0.05 M, are computed. Each sequence consists of 220 evolutionary intervals. From a comparison between the observed and calculated physical parameters we conclude that UV Thi is in an early evolutionary phase before the turn-off point.展开更多
An external proton beam system with a detection sensitivity of 10 g for ruthenium was used to study DNA. A metal- organic compound tris (4,7- diphenylphenanthroline) ruthenium (Ⅱ) [Ru(DiP)32-] was chosen as a metal m...An external proton beam system with a detection sensitivity of 10 g for ruthenium was used to study DNA. A metal- organic compound tris (4,7- diphenylphenanthroline) ruthenium (Ⅱ) [Ru(DiP)32-] was chosen as a metal marker. The target DNA labeled with Ru (DiP)32- was electrophoresed in an agarose gel and then was analysed by PIXE. The DNA sample with the metal marker showed clearly Ru peaks in the PIXE spectra, while the control showed no Ru peak at all. This method can be used to study biology at the DNA level.展开更多
Aging of a solid composite propellant containing HTPB/AP/AL was performed in order to validate the conformance of the accelerated aging data to the Arrhenius law. The main objective of the work was to examine the infl...Aging of a solid composite propellant containing HTPB/AP/AL was performed in order to validate the conformance of the accelerated aging data to the Arrhenius law. The main objective of the work was to examine the influence of the aziridine bonding agents family on the propellant aging. Aging of the prepared propellant samples was conducted as follows: 1. Four samples, one free of bonding agents, and three containing aziridine based bonding agents MAPO,HX-752, MAT4 were aged at 65°C. 2. Another four samples based on HX-752, MAT4 with different curing agents were aged at 65°C. The measured mechanical properties of the free bonding agent propellant samples were very far from the specifications and this illustrates the importance of the bonding agents in both the preparation and the aging phases.The prepared bonding agent 'MAT4' gave remarkable improvements of the mechanical properties comparing with HX-752 and MAPO. The aziridine bonding agents family inhibited the rate of decomposition of the propellant during the aging periods and supported the propellant matrix against decomposition at the elevate temperatures. Using of HMDI as curing agent gave slight better mechanical properties to the IPDI.展开更多
The study of the phase equilibrium characteristics of CO_(2)-ionic liquids(ILs)as new absorption-compression type refrigeration working pairs is of great importance.Three kinds of ILs,i.e.,[emim][FAP],[bmim][FAP]and[h...The study of the phase equilibrium characteristics of CO_(2)-ionic liquids(ILs)as new absorption-compression type refrigeration working pairs is of great importance.Three kinds of ILs,i.e.,[emim][FAP],[bmim][FAP]and[hmim][FAP],were chosen as potential absorbents.The solubility of CO_(2)in these ILs was measured experimentally within 0 to 5.0 MPa at temperatures of 293.15 K to 333.15 K,and the effects of temperature,pressure,IL anion and cation structure and stirring action on CO_(2)solubility were also discussed and analyzed.The results showed that the longer alkyl chains in an identical IL family,the alkyl fluoride group in IL anions and the stirring action by a magnetic stirrer had positive effects on the solubility of CO_(2).In the three ILs,[hmim][FAP]possessed the best performance for CO_(2)absorption;the solubility of CO_(2)reached 0.7641 at a pressure of 5 MPa and temperature of 293.15 K,the maximum solubility measured in this work.The CO_(2)-[hmim][FAP]binary mixture is recommended as a potentially applicable working pair for CO_(2)absorption-compression refrigeration systems.展开更多
文摘Resorbable bioceramics are attractive for medical applications such as bone substitution. Biochemical analysis on cells cultured on these biomaterials is vital to predict the impact of the materials in vivo and RNA extraction is an essential step in gene expression study using RT-qPCR. In this study, we describe simple modifications to the TRIzol? RNA extraction protocol widely used in biology and these allow high-yield extraction of RNA from cells on resorbable calcium phosphates. Without the modifications, RNA is trapped in the co-precipitated calcium compounds, rendering TRIzol? extraction method infeasible. Among the modifications, the use of extra TRIzol? to dilute the lysate before the RNA precipitation step is critical for extraction of RNA from porous ?-tricalcium phosphate (?-TCP) discs. We also investigate the rationale behind the undesirable precipitation so as to provide clues about the modifications required for other resorbable materials with high application potential in bone tissue engineering.
基金the National NaturalScience Foundation of China fOr the research grants. ElOy Rodrfguez acknowIedges partialresearch suPport
文摘UV Tri was observed photometrically from 1999 to 2000 at the Xinglong Station of the National Astronomical Observatories, Chinese Academy of Sciences, and was also observed with Stromgren uvbyHβ filter system at the Sierra Nevada Observatory (Spain) in 2000. From period analyses of the data, three pulsation frequencies, 9.3299 c d-1 10.8483 cd-1 and 3.6035 cd-1 were obtained. We derived color indices: b - y = 0.215, m1 = 0.169, c1 = 0.783, and β = 2.775. With these indices and some calibrations, we obtain: Mv = 2.44, Mbol = 2.27, logL/L = 0.99, and log Teff = 3.875. Evolutionary sequences of stellar models with 1.00-2.00 solar masses, at steps of 0.05 M, are computed. Each sequence consists of 220 evolutionary intervals. From a comparison between the observed and calculated physical parameters we conclude that UV Thi is in an early evolutionary phase before the turn-off point.
基金This work was partially supported by the National Natural Science Foundation of China under grant No.18 60 122
文摘An external proton beam system with a detection sensitivity of 10 g for ruthenium was used to study DNA. A metal- organic compound tris (4,7- diphenylphenanthroline) ruthenium (Ⅱ) [Ru(DiP)32-] was chosen as a metal marker. The target DNA labeled with Ru (DiP)32- was electrophoresed in an agarose gel and then was analysed by PIXE. The DNA sample with the metal marker showed clearly Ru peaks in the PIXE spectra, while the control showed no Ru peak at all. This method can be used to study biology at the DNA level.
文摘Aging of a solid composite propellant containing HTPB/AP/AL was performed in order to validate the conformance of the accelerated aging data to the Arrhenius law. The main objective of the work was to examine the influence of the aziridine bonding agents family on the propellant aging. Aging of the prepared propellant samples was conducted as follows: 1. Four samples, one free of bonding agents, and three containing aziridine based bonding agents MAPO,HX-752, MAT4 were aged at 65°C. 2. Another four samples based on HX-752, MAT4 with different curing agents were aged at 65°C. The measured mechanical properties of the free bonding agent propellant samples were very far from the specifications and this illustrates the importance of the bonding agents in both the preparation and the aging phases.The prepared bonding agent 'MAT4' gave remarkable improvements of the mechanical properties comparing with HX-752 and MAPO. The aziridine bonding agents family inhibited the rate of decomposition of the propellant during the aging periods and supported the propellant matrix against decomposition at the elevate temperatures. Using of HMDI as curing agent gave slight better mechanical properties to the IPDI.
基金supported by the National Natural Science Foundation of China(No.51676129)。
文摘The study of the phase equilibrium characteristics of CO_(2)-ionic liquids(ILs)as new absorption-compression type refrigeration working pairs is of great importance.Three kinds of ILs,i.e.,[emim][FAP],[bmim][FAP]and[hmim][FAP],were chosen as potential absorbents.The solubility of CO_(2)in these ILs was measured experimentally within 0 to 5.0 MPa at temperatures of 293.15 K to 333.15 K,and the effects of temperature,pressure,IL anion and cation structure and stirring action on CO_(2)solubility were also discussed and analyzed.The results showed that the longer alkyl chains in an identical IL family,the alkyl fluoride group in IL anions and the stirring action by a magnetic stirrer had positive effects on the solubility of CO_(2).In the three ILs,[hmim][FAP]possessed the best performance for CO_(2)absorption;the solubility of CO_(2)reached 0.7641 at a pressure of 5 MPa and temperature of 293.15 K,the maximum solubility measured in this work.The CO_(2)-[hmim][FAP]binary mixture is recommended as a potentially applicable working pair for CO_(2)absorption-compression refrigeration systems.
