The ultra high strength SiC particles （SiCp） reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were ana...The ultra high strength SiC particles （SiCp） reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy （TEM） and energy dispersive spectrometry （EDS）. Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution. After single-stage solution aging treatment, fine precipitates of both η and AlZnMgCu-rich phase can be found both intragranularly and intergranularly. While after the two-stage solution, an amorphous Si-Cu-Al-O （5 nm） layer appears at the interface. The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size. Heat treatments can significantly improve the fracture toughness of the composite. The fracture toughness first decreases then increases with the elongation of the aging time.展开更多
AIM： To examine the relationships between pre-diag- nostic biomarkers and colorectal cancer risk and assess their relevance in predictive models.METHODS： A nested case-control study was designed to include all first...AIM： To examine the relationships between pre-diag- nostic biomarkers and colorectal cancer risk and assess their relevance in predictive models.METHODS： A nested case-control study was designed to include all first primary incident colorectal cancer cases diagnosed between inclusion in the SUpplemen- tation en VItamines et Min^raux AntioXydants cohort in 1994 and the end of follow-up in 2007. Cases （n = 50） were matched with two randomly selected con- trols （n = 100）. Conditional logistic regression models were used to investigate the associations between pre- diagnostic levels of hs-CRP, adiponectin, leptin, soluble vascular cell adhesion molecule-1 （sVCAM-1）, soluble intercellular adhesion molecule-I, E-selectin, monocyte chemoattractant protein-1 and colorectal cancer risk. Area under the receiver operating curves （AUC） and relative integrated discrimination improvement （RIDI） statistics were used to assess the discriminatory poten- tial of the models. RESULTS： Plasma adiponectin level was associated with decreased colorectal cancer risk （P for linear trend -- 0.03）. Quartiles of sVCAM-1 were associated with increased colorectal cancer risk （P for linear trend = 0.02）. No association was observed with any of the other biomarkers. Compared to standard models with known risk factors, those including both adiponectin and sVCAM-1 had substantially improved performance for colorectal cancer risk prediction （P for AUC improve- ment = 0.01, RIDI = 26.5%）. CONCLUSION： These results suggest that pre-diag- nostic plasma adiponectin and sVCAM-1 levels are as- sociated with decreased and increased colorectal cancer risk, respectively. These relationships must be confirmed in large validation studies.展开更多
Ionic liquids （ILs） have attracted many attentions in the dissolution of cellulose due to their unique physicochemical properties as green solvents. However, the mechanism of dissolution is still under debate. In th...Ionic liquids （ILs） have attracted many attentions in the dissolution of cellulose due to their unique physicochemical properties as green solvents. However, the mechanism of dissolution is still under debate. In this work, computational investigation for the mechanisms of dissolution of cellulose in [Bmim]Cl, [Emim]C1 and [Emim]OAc ILs was performed, and it was focused on the process of breakage of cellulose chain and ring opening using cellobiose as a model molecule. The detailed mechanism and reaction energy barriers were computed for various possible pathways by density functional theoretical method. The key finding was that 1Ls catalyze the dissolution process by synergistic effect of anion and cation, which led to the cleavage of cellulose chain and formation of derivatives of cellulose. The investigation on ring opening process ofcellobiose suggested that carbene formed in ILs played an important role in the side reaction of cellulose, and it facilitated the formation of a covalent bond between cellulose and imidazolium core. These computation results may provide new perspective to understand and apply ILs for pretreatment of cellulose.展开更多
The effect of solution treatment time on the post-formed plasticity and ductile fracture of 7075 aluminum alloy in the hot stamping process was studied.Tensile tests were conducted on the specimens subjected to the ho...The effect of solution treatment time on the post-formed plasticity and ductile fracture of 7075 aluminum alloy in the hot stamping process was studied.Tensile tests were conducted on the specimens subjected to the hot stamping process with different solution treatment time.The digital image correlation(DIC)analysis was used to obtain the strain of the specimen.Based on the experiments and modeling,the Yld2000-3d yield criterion and the DF2014 ductile fracture criterion were calibrated and used to characterize the anisotropy and fracture behavior of the metal,respectively.Furthermore,the microstructure of specimens was studied.The experimental and simulation results indicate that the 7075 aluminum alloy retains distinct anisotropy after the hot stamping process,and there is no obvious effect of extending the solution treatment time on the material anisotropy.However,it is found that a longer solution treatment time can increase the fracture strain of the aluminum alloy during the hot stamping process,which may be related to the decrease of the second-phase particles size.展开更多
OBJECTIVE: To explore the characteristics of Helicobacter pylori (H. pylori) antigen in serum and to evaluate its clinical diagnostic value. METHODS: Enzyme-linked immunosorbant assay (ELISA) was developed to detect t...OBJECTIVE: To explore the characteristics of Helicobacter pylori (H. pylori) antigen in serum and to evaluate its clinical diagnostic value. METHODS: Enzyme-linked immunosorbant assay (ELISA) was developed to detect the soluble H. pylori antigen (S-Hp) and circulatory specific H. pylori antigen immunocomplexes (Hp-IC) in serum. RESULTS: The positive rate of S-Hp was 90.91% from 66 patients with H. pylori infection, which was much greater than 0% found in 28 controls (P展开更多
基金Project (02Gky2004) supported by Hunan Provincial Science and Technology Department, China
文摘The ultra high strength SiC particles （SiCp） reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy （TEM） and energy dispersive spectrometry （EDS）. Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution. After single-stage solution aging treatment, fine precipitates of both η and AlZnMgCu-rich phase can be found both intragranularly and intergranularly. While after the two-stage solution, an amorphous Si-Cu-Al-O （5 nm） layer appears at the interface. The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size. Heat treatments can significantly improve the fracture toughness of the composite. The fracture toughness first decreases then increases with the elongation of the aging time.
基金Supported by A grant from the French National Cancer Institute (Institut National du Cancer), No. INCa 2007-1-SPC-3
文摘AIM： To examine the relationships between pre-diag- nostic biomarkers and colorectal cancer risk and assess their relevance in predictive models.METHODS： A nested case-control study was designed to include all first primary incident colorectal cancer cases diagnosed between inclusion in the SUpplemen- tation en VItamines et Min^raux AntioXydants cohort in 1994 and the end of follow-up in 2007. Cases （n = 50） were matched with two randomly selected con- trols （n = 100）. Conditional logistic regression models were used to investigate the associations between pre- diagnostic levels of hs-CRP, adiponectin, leptin, soluble vascular cell adhesion molecule-1 （sVCAM-1）, soluble intercellular adhesion molecule-I, E-selectin, monocyte chemoattractant protein-1 and colorectal cancer risk. Area under the receiver operating curves （AUC） and relative integrated discrimination improvement （RIDI） statistics were used to assess the discriminatory poten- tial of the models. RESULTS： Plasma adiponectin level was associated with decreased colorectal cancer risk （P for linear trend -- 0.03）. Quartiles of sVCAM-1 were associated with increased colorectal cancer risk （P for linear trend = 0.02）. No association was observed with any of the other biomarkers. Compared to standard models with known risk factors, those including both adiponectin and sVCAM-1 had substantially improved performance for colorectal cancer risk prediction （P for AUC improve- ment = 0.01, RIDI = 26.5%）. CONCLUSION： These results suggest that pre-diag- nostic plasma adiponectin and sVCAM-1 levels are as- sociated with decreased and increased colorectal cancer risk, respectively. These relationships must be confirmed in large validation studies.
基金Supported by the National Natural Science Foundation of China(21210006,21276255,21406230,91434111)the Natural Science Foundation of Beijing of China(2131005,2142029)
文摘Ionic liquids （ILs） have attracted many attentions in the dissolution of cellulose due to their unique physicochemical properties as green solvents. However, the mechanism of dissolution is still under debate. In this work, computational investigation for the mechanisms of dissolution of cellulose in [Bmim]Cl, [Emim]C1 and [Emim]OAc ILs was performed, and it was focused on the process of breakage of cellulose chain and ring opening using cellobiose as a model molecule. The detailed mechanism and reaction energy barriers were computed for various possible pathways by density functional theoretical method. The key finding was that 1Ls catalyze the dissolution process by synergistic effect of anion and cation, which led to the cleavage of cellulose chain and formation of derivatives of cellulose. The investigation on ring opening process ofcellobiose suggested that carbene formed in ILs played an important role in the side reaction of cellulose, and it facilitated the formation of a covalent bond between cellulose and imidazolium core. These computation results may provide new perspective to understand and apply ILs for pretreatment of cellulose.
基金the National Natural Science Foundation of China(No.U1760205).
文摘The effect of solution treatment time on the post-formed plasticity and ductile fracture of 7075 aluminum alloy in the hot stamping process was studied.Tensile tests were conducted on the specimens subjected to the hot stamping process with different solution treatment time.The digital image correlation(DIC)analysis was used to obtain the strain of the specimen.Based on the experiments and modeling,the Yld2000-3d yield criterion and the DF2014 ductile fracture criterion were calibrated and used to characterize the anisotropy and fracture behavior of the metal,respectively.Furthermore,the microstructure of specimens was studied.The experimental and simulation results indicate that the 7075 aluminum alloy retains distinct anisotropy after the hot stamping process,and there is no obvious effect of extending the solution treatment time on the material anisotropy.However,it is found that a longer solution treatment time can increase the fracture strain of the aluminum alloy during the hot stamping process,which may be related to the decrease of the second-phase particles size.
文摘OBJECTIVE: To explore the characteristics of Helicobacter pylori (H. pylori) antigen in serum and to evaluate its clinical diagnostic value. METHODS: Enzyme-linked immunosorbant assay (ELISA) was developed to detect the soluble H. pylori antigen (S-Hp) and circulatory specific H. pylori antigen immunocomplexes (Hp-IC) in serum. RESULTS: The positive rate of S-Hp was 90.91% from 66 patients with H. pylori infection, which was much greater than 0% found in 28 controls (P
