BACKGROUND:With the objective of developing a locally-produced radioactive stent,the present study used in vivo animal experiments to explore apoptosis of proliferative smooth muscle cells resulting from facilitation ...BACKGROUND:With the objective of developing a locally-produced radioactive stent,the present study used in vivo animal experiments to explore apoptosis of proliferative smooth muscle cells resulting from facilitation of the expression of genes caused byγ-radiation in order to prevent bile duct restenosis.We therefore explored the effects and significance ofγ-radiation on the activity of caspase-3,Fas and Bcl-2 genes in apoptosis of proliferative smooth muscle cells in the bile duct walls of dogs.METHODS:Twelve dogs were randomly divided into 2 groups(6 in each group).A postinjury bile duct stenosis model was established and radioactive 103 Pd(103 palladium)or ordinary bile duct stents were implanted into the bile ducts.HE staining,RT-PCR and immunohistochemistry were used to detect the proliferation and apoptosis of bile duct smooth muscle cells in proliferative endomembrane and the expression of related caspase-3,Bcl-2 and Fas genes.RESULTS:The expression of caspase-3 and Fas genes in the bile duct tissues of dogs with radioactive stents was higher than that of dogs with ordinary stents.There was significant apoptosis of proliferative smooth muscle cells in the bile ducts.The expression of the Bcl-2 gene in the bile duct tissues of dogs with radioactive stents was lower than that in those with ordinary stents.There was significant apoptosis of proliferative smooth muscle cells in the dogs with low Bcl-2 gene expression.CONCLUSIONS:Radiation increases the activity of caspase-3 and Fas genes and is associated with apoptosis.The radioactive 103 Pd stent may facilitate apoptosis of proliferative smooth muscle cells in the bile ducts of dogs by activating these genes.The Bcl-2 gene expression level is correlated with the occurrence of apoptosis and the radiosusceptibility of cells.展开更多
Cosmogenic Ne isotopes are stable and are routinely used for constraining the timing of events and the rate of surface change beyond the limit that can be studied with radionuclides ^10Be, ^26Al, and ^36Cl. Cosmogenic...Cosmogenic Ne isotopes are stable and are routinely used for constraining the timing of events and the rate of surface change beyond the limit that can be studied with radionuclides ^10Be, ^26Al, and ^36Cl. Cosmogenic Ne analysis can be used in quartz and in a range of other minerals. Analysis typically requires significantly less material than do cosmogenic ^10Be and ^26Al, opening up the technique for small samples--individual pebbles in fiver sediments, for example. Analysis is easier and faster than for radionuclides, not least because Ne measurements do not require significant chemical procedures. However, the presence of other sources of Ne in minerals tends to restrict the use of cosmogenic ^21Ne to old landscapes and long exposure durations. In this review we briefly outline the background of cosmogenic Ne production in rocks and minerals at the Earth＇s surface, then document the key uses of the technique by highlighting some earlier studies, and finish with a short perspective on the future of the technique.展开更多
Noblesse multi-collector noble gas mass spec- trometer is specially designed for multi-collection of Ar isotopes with different beam sizes, especially for small ion beams, precisely, and hence is perfectly suitable fo...Noblesse multi-collector noble gas mass spec- trometer is specially designed for multi-collection of Ar isotopes with different beam sizes, especially for small ion beams, precisely, and hence is perfectly suitable for ^40Ar/^39Ar geochronology. We have analyzed widely used sanidine, muscovite, and biotite standards with recom- mended ages of - 1.2-133 Ma, with the aim to assess the reliability of Noblesse for ^40Ar/^39Ar dating. An ESI MIR10 30W CO2 laser was used for total fusion or incremental heating samples. Extracted gases were routinely purified by four SAES NP10 getters （one at - 400 ℃ and others at room temperature）. A GP50 getter and a metal cold finger cooled by liquid N （- 196 ℃） were also attached for additional purification if necessary. The Ar isotopes were then measured by Noblesse using Faraday or multiplier according to the signal intensities. Over a period of 1.5 months 337 air calibrations produced a weighted mean ^40Ar/^36Ar of 296.50 ± 0.08 （2σ, MSWD = 4.77）. Fish Canyon sanidine is used to calculate J-values, which show good linear relationship with position in irradiation. The age of four mineral standards （Alder Creek sanidine, Brione muscovite, Yabachi sanidine, and Fangshan biotite） are within error of the accepted ages. Five Alder Creek sanidine aliquots yielded an age range of 1.174-1.181 ± 0.013 Ma （2σ） which broadly overlaps the established age of the standard and the uncertainty approaches those of the foremost Ar/Ar laboratories in the world. The weighted mean ages of four Brione muscovite aliquots （18.75 i 0.16 Ma, 2σ）, five Yabachi sanidine aliquots （29.50 ± 0.19 Ma, 2σ）, and three Fangshan bio- tite aliquots （133.0 ± 0.76 Ma, 2σ） are consistent with the recommended values of these standards, and the uncer- tainties are typical of modem Ar/Ar laboratories world- wide.展开更多
Geologists have been paying much attention to the characteristics and age of the basement of the Tarim Block. Recently, some isotopic ages for the Precambrian rocks in the margin areas of the Tarim Block have been obt...Geologists have been paying much attention to the characteristics and age of the basement of the Tarim Block. Recently, some isotopic ages for the Precambrian rocks in the margin areas of the Tarim Block have been obtained. The oldest age presented by the above study is 2487±5.1 Ma determined with evaporated Pb-isotope method for zircons of the blue quartz-bearing granite from the Kuruktag area. However, the possibility of the Archaean basement of Tarim Block was only deduced. In this study the age of 3.3 Ga展开更多
基金supported by grants from the Liaoning Research Project for Institution of Higher Education(Key Research Project,05L445)the Liaoning Research Project for Institution of Nature(Key Research Project,20042063)and the Liaoning Research Project for Institution of Science and Technology Planning Item(2006225001-6).
文摘BACKGROUND:With the objective of developing a locally-produced radioactive stent,the present study used in vivo animal experiments to explore apoptosis of proliferative smooth muscle cells resulting from facilitation of the expression of genes caused byγ-radiation in order to prevent bile duct restenosis.We therefore explored the effects and significance ofγ-radiation on the activity of caspase-3,Fas and Bcl-2 genes in apoptosis of proliferative smooth muscle cells in the bile duct walls of dogs.METHODS:Twelve dogs were randomly divided into 2 groups(6 in each group).A postinjury bile duct stenosis model was established and radioactive 103 Pd(103 palladium)or ordinary bile duct stents were implanted into the bile ducts.HE staining,RT-PCR and immunohistochemistry were used to detect the proliferation and apoptosis of bile duct smooth muscle cells in proliferative endomembrane and the expression of related caspase-3,Bcl-2 and Fas genes.RESULTS:The expression of caspase-3 and Fas genes in the bile duct tissues of dogs with radioactive stents was higher than that of dogs with ordinary stents.There was significant apoptosis of proliferative smooth muscle cells in the bile ducts.The expression of the Bcl-2 gene in the bile duct tissues of dogs with radioactive stents was lower than that in those with ordinary stents.There was significant apoptosis of proliferative smooth muscle cells in the dogs with low Bcl-2 gene expression.CONCLUSIONS:Radiation increases the activity of caspase-3 and Fas genes and is associated with apoptosis.The radioactive 103 Pd stent may facilitate apoptosis of proliferative smooth muscle cells in the bile ducts of dogs by activating these genes.The Bcl-2 gene expression level is correlated with the occurrence of apoptosis and the radiosusceptibility of cells.
基金supported by the basic scientific research fund, Institute of Geology, China Earthquake Administration (Grant Nos. IGCEA1504 and IGCEA1417)
文摘Cosmogenic Ne isotopes are stable and are routinely used for constraining the timing of events and the rate of surface change beyond the limit that can be studied with radionuclides ^10Be, ^26Al, and ^36Cl. Cosmogenic Ne analysis can be used in quartz and in a range of other minerals. Analysis typically requires significantly less material than do cosmogenic ^10Be and ^26Al, opening up the technique for small samples--individual pebbles in fiver sediments, for example. Analysis is easier and faster than for radionuclides, not least because Ne measurements do not require significant chemical procedures. However, the presence of other sources of Ne in minerals tends to restrict the use of cosmogenic ^21Ne to old landscapes and long exposure durations. In this review we briefly outline the background of cosmogenic Ne production in rocks and minerals at the Earth＇s surface, then document the key uses of the technique by highlighting some earlier studies, and finish with a short perspective on the future of the technique.
基金funded by The National Key R&D Program of China(2016YFC0600405)The National Natural Science Foundation of China(Grant No.40903022)
文摘Noblesse multi-collector noble gas mass spec- trometer is specially designed for multi-collection of Ar isotopes with different beam sizes, especially for small ion beams, precisely, and hence is perfectly suitable for ^40Ar/^39Ar geochronology. We have analyzed widely used sanidine, muscovite, and biotite standards with recom- mended ages of - 1.2-133 Ma, with the aim to assess the reliability of Noblesse for ^40Ar/^39Ar dating. An ESI MIR10 30W CO2 laser was used for total fusion or incremental heating samples. Extracted gases were routinely purified by four SAES NP10 getters （one at - 400 ℃ and others at room temperature）. A GP50 getter and a metal cold finger cooled by liquid N （- 196 ℃） were also attached for additional purification if necessary. The Ar isotopes were then measured by Noblesse using Faraday or multiplier according to the signal intensities. Over a period of 1.5 months 337 air calibrations produced a weighted mean ^40Ar/^36Ar of 296.50 ± 0.08 （2σ, MSWD = 4.77）. Fish Canyon sanidine is used to calculate J-values, which show good linear relationship with position in irradiation. The age of four mineral standards （Alder Creek sanidine, Brione muscovite, Yabachi sanidine, and Fangshan biotite） are within error of the accepted ages. Five Alder Creek sanidine aliquots yielded an age range of 1.174-1.181 ± 0.013 Ma （2σ） which broadly overlaps the established age of the standard and the uncertainty approaches those of the foremost Ar/Ar laboratories in the world. The weighted mean ages of four Brione muscovite aliquots （18.75 i 0.16 Ma, 2σ）, five Yabachi sanidine aliquots （29.50 ± 0.19 Ma, 2σ）, and three Fangshan bio- tite aliquots （133.0 ± 0.76 Ma, 2σ） are consistent with the recommended values of these standards, and the uncer- tainties are typical of modem Ar/Ar laboratories world- wide.
文摘Geologists have been paying much attention to the characteristics and age of the basement of the Tarim Block. Recently, some isotopic ages for the Precambrian rocks in the margin areas of the Tarim Block have been obtained. The oldest age presented by the above study is 2487±5.1 Ma determined with evaporated Pb-isotope method for zircons of the blue quartz-bearing granite from the Kuruktag area. However, the possibility of the Archaean basement of Tarim Block was only deduced. In this study the age of 3.3 Ga
