Polyvinyl alcohol gelatin hydrogels were fabricated using genipin as a crosslinking agent for bone regeneration application. Optimized formulation of PVA-GE hydrogel was fabricated using genipin as crosslinking agent....Polyvinyl alcohol gelatin hydrogels were fabricated using genipin as a crosslinking agent for bone regeneration application. Optimized formulation of PVA-GE hydrogel was fabricated using genipin as crosslinking agent. Characterizations such as FTIR, morphology, porosity, pore size, degradation and swelling rate were investigated. Bone regeneration potential of optimized genipin cross-linked polyvinyl alcohol-gelatin (PVA20) hydrogels was assessed by implanting in rabbit’s femur defect for 1, 5 and 15 weeks period. Results showed interconnected porosity as observed in scanning electron microscopy and successful crosslinking as confirmed by FTIR analysis. Increased porosity (92% ± 2.46%) and pore size distribution (100 - 200 μm) were also observed as well as decrease in swelling rate (426% ± 10.50%). Bone formation was evident in micro-CT after 5 and 15 days of in vivo implantation period. Micro-CT analysis showed 32.67% increased bone formation of PVA-GE hydrogel defect compared with negative control after 15 weeks of in-vivo implantation. Histological analyses showed no inflammatory reaction post implantation and increase in cell matrix formation after 5 and 15 weeks. The combined physical and chemical method of crosslinking promises improved mechanical properties of PVA-GE hydrogel making it a potential scaffold for bone tissue engineering applications.展开更多
The bacterial diversity and abundance in snow of the summit(8201 m) of Cho Oyu mountain,Tibet,were analyzed by 16S rRNA gene sequencing followed by scanning electronic microscopy analysis.Most of bacteria were found t...The bacterial diversity and abundance in snow of the summit(8201 m) of Cho Oyu mountain,Tibet,were analyzed by 16S rRNA gene sequencing followed by scanning electronic microscopy analysis.Most of bacteria were found to be of spherical or oval shape(>95%).Bacterial 16S rDNA sequences were classified into 5 genera(Caulobacter,Ralstonia,Cupriavidus,Pelomonas and Pseudomonas).Gammaproteobacteria were the most abundant(91.25%) among the library that consists of 594 clones.The sequences found in this study are highly similar to those previously retrieved from other cold en-vironments,such as ice core,sea ice,permafrost and snow.The results showed that the cold and barren environments strongly influence the survival of bacteria.The high similarity among sequences retrieved from snow sample and other places,such as ocean,soil and water,suggested that the bacteria in snow,soil and water environments have the same origin.展开更多
Nowadays, internet-based surveys are increasingly used for data collection, because their usage is simple and cheap. Also they give fast access to a large group of respondents. There are many factors affecting interne...Nowadays, internet-based surveys are increasingly used for data collection, because their usage is simple and cheap. Also they give fast access to a large group of respondents. There are many factors affecting internet surveys, such as measurement, survey design and sampling selection bias. The sampling has an important place in selection bias in internet survey. In terms of sample selection, the type of access to internet surveys has several limitations. There are internet surveys based on restricted access and on voluntary participation, and these are characterized by their implementation according to the type of survey. It can be used probability and non-probability sampling, both of which may lead to biased estimates. There are different ways to correct for selection biases;poststratification or weighting class adjustments, raking or rim weighting, generalized regression modeling and propensity score adjustments. This paper aims to describe methodological problems about selection bias issues and to give a review in internet surveys. Also the objective of this study is to show the effect of various correction techniques for reducing selection bias.展开更多
Corrosion behavior of heavily drawn bundled Copper-niobium filamentarymicro-composite was studied as a function of niobium content to develop the relationship betweenmicrostructure and corrosion behavior in aqueous 30...Corrosion behavior of heavily drawn bundled Copper-niobium filamentarymicro-composite was studied as a function of niobium content to develop the relationship betweenmicrostructure and corrosion behavior in aqueous 30 percent HCl-FeCl_3 solution. TEM observationrevealed that niobium filaments were distributed regularly in copper matrix along the sides of atriangular unit cell in the transverse section and more sub-grain boundaries were absorbed atcopper/niobium phase boundaries with increasing niobium content. The corrosion potential and rate inaqueous 30 percent HCl-10 percent FeCl_3 was-680.3m V_(SHE) and 1.179 X 10^(-5)A/cm^2. Thecorrosion potential and rate decreased as increasing niobium content and FeCl_3. The yield stresscan be described as the sum of the substructure strengthening component due to elongated grains,subgrains and/or cells, the phase boundary strengthening term associated with the Hall-Petch typeinteraction between dislocations and phase boundaries and precipitate strengthening component.展开更多
Petro Gram is an Excel?based magmatic petrology program that generates numerical and graphical models.Petro Gram can model the magmatic processes such as melting,crystallization,assimilation and magma mixing based on ...Petro Gram is an Excel?based magmatic petrology program that generates numerical and graphical models.Petro Gram can model the magmatic processes such as melting,crystallization,assimilation and magma mixing based on the trace element and isotopic data.The program can produce both inverse and forward geochemical models for melting processes(e.g.forward model for batch,fractional and dynamic melting,and inverse model for batch and dynamic melting).However,the program uses a forward modeling approach for magma differentiation processes such as crystallization(EC:Equilibruim Crystallization,FC:Fractional Crystallization,IFC:Imperfect Fractional Crystallization and In-situ Crystallization),assimilation(AFC:Assimilation Fractional Crystallization,Decoupled FC-A:Decoupled Fractional Crystallization and Assimillation,A-IFC:Assimilation and Imperfect Fractional Crystallization)and magma mixing.One of the most important advantages of the program is that the melt composition obtained from any partial melting model can be used as a starting composition of the crystallization,assimilation and magma mixing.In addition,Petro Gram is able to carry out the classification,tectonic setting,multi-element(spider)and isotope correlation diagrams,and basic calculations including Mg^#,Eu/Eu^*,εSrandεNdwidely used in magmatic petrology.展开更多
In the vicinity of Konya （Turkey）,mafic,micro-porphyritic sub-volcanic rocks intrude into the Mesozoic units,which represents the only example of such a rock type in the region.40Ar/39Ar dating of two whole rock sam...In the vicinity of Konya （Turkey）,mafic,micro-porphyritic sub-volcanic rocks intrude into the Mesozoic units,which represents the only example of such a rock type in the region.40Ar/39Ar dating of two whole rock samples from the sub-volcanics gave ages of 13.72±0.13 and 12.40±0.11 Ma,suggesting temporal association to the Late Miocene-Pliocene high-K calc-alkaline volcanism in the region.The mineral chemistry and geochemical data permit us to classify the rocks as ＂minette＂ lamprophyres.They include diopside and phlogopite phenocrysts in a microcrystalline groundmass composed of sanidine,phlogopite,diopside and titano-magnetite.Segregation and ocelli-like globular structures occur commonly in the samples.In terms of major elements,the lamprophyres are calcalkaline,and potassic to ultrapotassic rocks.All the lamprophyres display strong enrichments in LILE （Rb,Ba,K,Sr）,radiogenic elements （Th,U） and LREE （La,Ce） and prominent negative Nb,Ta,and Ti anomalies on primordial mantle-normalized trace element diagrams.Geochemical data suggest that the lamprophyres and high-K calc-alkaline rocks in the region derived from a subduction-modified lithospheric mantle source affected by different metasomatic events.Lamprophyric magmatism sourced phlogopite-bearing veins generated by sediment-related metasomatism via subduction,but high-K calc-alkaline magmas are possibly derived from a mantle source affected by fluid-rich metasomatism.展开更多
文摘Polyvinyl alcohol gelatin hydrogels were fabricated using genipin as a crosslinking agent for bone regeneration application. Optimized formulation of PVA-GE hydrogel was fabricated using genipin as crosslinking agent. Characterizations such as FTIR, morphology, porosity, pore size, degradation and swelling rate were investigated. Bone regeneration potential of optimized genipin cross-linked polyvinyl alcohol-gelatin (PVA20) hydrogels was assessed by implanting in rabbit’s femur defect for 1, 5 and 15 weeks period. Results showed interconnected porosity as observed in scanning electron microscopy and successful crosslinking as confirmed by FTIR analysis. Increased porosity (92% ± 2.46%) and pore size distribution (100 - 200 μm) were also observed as well as decrease in swelling rate (426% ± 10.50%). Bone formation was evident in micro-CT after 5 and 15 days of in vivo implantation period. Micro-CT analysis showed 32.67% increased bone formation of PVA-GE hydrogel defect compared with negative control after 15 weeks of in-vivo implantation. Histological analyses showed no inflammatory reaction post implantation and increase in cell matrix formation after 5 and 15 weeks. The combined physical and chemical method of crosslinking promises improved mechanical properties of PVA-GE hydrogel making it a potential scaffold for bone tissue engineering applications.
基金the Knowledge Innovation Project of Chinese Academy of Sciences (Grant No.KSCX2-SW-331)
文摘The bacterial diversity and abundance in snow of the summit(8201 m) of Cho Oyu mountain,Tibet,were analyzed by 16S rRNA gene sequencing followed by scanning electronic microscopy analysis.Most of bacteria were found to be of spherical or oval shape(>95%).Bacterial 16S rDNA sequences were classified into 5 genera(Caulobacter,Ralstonia,Cupriavidus,Pelomonas and Pseudomonas).Gammaproteobacteria were the most abundant(91.25%) among the library that consists of 594 clones.The sequences found in this study are highly similar to those previously retrieved from other cold en-vironments,such as ice core,sea ice,permafrost and snow.The results showed that the cold and barren environments strongly influence the survival of bacteria.The high similarity among sequences retrieved from snow sample and other places,such as ocean,soil and water,suggested that the bacteria in snow,soil and water environments have the same origin.
文摘Nowadays, internet-based surveys are increasingly used for data collection, because their usage is simple and cheap. Also they give fast access to a large group of respondents. There are many factors affecting internet surveys, such as measurement, survey design and sampling selection bias. The sampling has an important place in selection bias in internet survey. In terms of sample selection, the type of access to internet surveys has several limitations. There are internet surveys based on restricted access and on voluntary participation, and these are characterized by their implementation according to the type of survey. It can be used probability and non-probability sampling, both of which may lead to biased estimates. There are different ways to correct for selection biases;poststratification or weighting class adjustments, raking or rim weighting, generalized regression modeling and propensity score adjustments. This paper aims to describe methodological problems about selection bias issues and to give a review in internet surveys. Also the objective of this study is to show the effect of various correction techniques for reducing selection bias.
文摘Corrosion behavior of heavily drawn bundled Copper-niobium filamentarymicro-composite was studied as a function of niobium content to develop the relationship betweenmicrostructure and corrosion behavior in aqueous 30 percent HCl-FeCl_3 solution. TEM observationrevealed that niobium filaments were distributed regularly in copper matrix along the sides of atriangular unit cell in the transverse section and more sub-grain boundaries were absorbed atcopper/niobium phase boundaries with increasing niobium content. The corrosion potential and rate inaqueous 30 percent HCl-10 percent FeCl_3 was-680.3m V_(SHE) and 1.179 X 10^(-5)A/cm^2. Thecorrosion potential and rate decreased as increasing niobium content and FeCl_3. The yield stresscan be described as the sum of the substructure strengthening component due to elongated grains,subgrains and/or cells, the phase boundary strengthening term associated with the Hall-Petch typeinteraction between dislocations and phase boundaries and precipitate strengthening component.
文摘Petro Gram is an Excel?based magmatic petrology program that generates numerical and graphical models.Petro Gram can model the magmatic processes such as melting,crystallization,assimilation and magma mixing based on the trace element and isotopic data.The program can produce both inverse and forward geochemical models for melting processes(e.g.forward model for batch,fractional and dynamic melting,and inverse model for batch and dynamic melting).However,the program uses a forward modeling approach for magma differentiation processes such as crystallization(EC:Equilibruim Crystallization,FC:Fractional Crystallization,IFC:Imperfect Fractional Crystallization and In-situ Crystallization),assimilation(AFC:Assimilation Fractional Crystallization,Decoupled FC-A:Decoupled Fractional Crystallization and Assimillation,A-IFC:Assimilation and Imperfect Fractional Crystallization)and magma mixing.One of the most important advantages of the program is that the melt composition obtained from any partial melting model can be used as a starting composition of the crystallization,assimilation and magma mixing.In addition,Petro Gram is able to carry out the classification,tectonic setting,multi-element(spider)and isotope correlation diagrams,and basic calculations including Mg^#,Eu/Eu^*,εSrandεNdwidely used in magmatic petrology.
基金supported by the Seluk University Scientific Research Projects Coordination (Project No:11201041)
文摘In the vicinity of Konya （Turkey）,mafic,micro-porphyritic sub-volcanic rocks intrude into the Mesozoic units,which represents the only example of such a rock type in the region.40Ar/39Ar dating of two whole rock samples from the sub-volcanics gave ages of 13.72±0.13 and 12.40±0.11 Ma,suggesting temporal association to the Late Miocene-Pliocene high-K calc-alkaline volcanism in the region.The mineral chemistry and geochemical data permit us to classify the rocks as ＂minette＂ lamprophyres.They include diopside and phlogopite phenocrysts in a microcrystalline groundmass composed of sanidine,phlogopite,diopside and titano-magnetite.Segregation and ocelli-like globular structures occur commonly in the samples.In terms of major elements,the lamprophyres are calcalkaline,and potassic to ultrapotassic rocks.All the lamprophyres display strong enrichments in LILE （Rb,Ba,K,Sr）,radiogenic elements （Th,U） and LREE （La,Ce） and prominent negative Nb,Ta,and Ti anomalies on primordial mantle-normalized trace element diagrams.Geochemical data suggest that the lamprophyres and high-K calc-alkaline rocks in the region derived from a subduction-modified lithospheric mantle source affected by different metasomatic events.Lamprophyric magmatism sourced phlogopite-bearing veins generated by sediment-related metasomatism via subduction,but high-K calc-alkaline magmas are possibly derived from a mantle source affected by fluid-rich metasomatism.
