The P receiver function includes P-to-SV converted phases and multiple reverberations of the discontinuities in the crust and mantle.The time of these phases is related to the crustal thickness and vp/vs ratio,and the...The P receiver function includes P-to-SV converted phases and multiple reverberations of the discontinuities in the crust and mantle.The time of these phases is related to the crustal thickness and vp/vs ratio,and the amplitude of these phases is mainly controlled by the velocity and density contrast of interfaces.By using H-κstacking method,this work estimated the crustal thickness and vP/vS ratio beneath the stations in the Guangdong province of South China.The velocity and density contrast(δβ-δρ)scanning stacking algorithm of the receiver function is applied to constrain the velocity and density contrast of the Moho in Guangdong province.This work analyzed the results of the crustal thickness,vp/vS ratio,and the velocity and density contrasts of Moho.The results indicate that the velocity contrast is higher beneath Yangjiang area in western Guangdong province and Nanao area in eastern Guangdong,which has a strong correlation with the distribution of geothermal springs in local areas and the characteristics of high heat flow.The velocity contrast of Moho has also a good correlation with the vP/vS ratio and the crustal thickness,which indicates that there is a strong material composition contrasts of the Moho in the study area.Velocity and density contrasts of Moho in some local area(such as western Guangdong)are somewhat consistent with the seismic activities.展开更多
The purpose of this research is to investigate the feasibility of using low contrast agent concentration with X-ray computed tomography in visualizing and diagnosing the human vascular system while minimizing the risk...The purpose of this research is to investigate the feasibility of using low contrast agent concentration with X-ray computed tomography in visualizing and diagnosing the human vascular system while minimizing the risk of toxicity to the patient. This research investigated the effect of several iodine contrast agent concentrations on the ability to extract and visualize human vessels using simulated computed tomography scans. Monte Carlo simulation was used to perform these computed tomography acquisitions. The simulated patient was based on actual computed tomography angiography data, where a technique was developed to simulate brain vessels with contrast agents ranging from 0 mg to 20 mg of iodine. The simulation used segmented patient data along with basic image processing techniques to model the various levels of iodine concentrations. Cone beam computed tomography projections of a patient injected with and without iodine were acquired in the simulations. Subtraction of the corresponding projections was performed to generate images caused by the contrast agent. Then, histogram analysis of these differences was used to assess the validity of extracting and visualizing the human vessels. The smallest amount of iodine, 0.5 mg, helped better visualize the brain vessels and 2 mg of iodine was high enough to show almost 90% of the vessels. Additionally, the vessels were clearly visible in all the subtracted images. This research showed very promising outcomes in using low concentrations of iodine. Thus, this study proposes for the pharmaceutical companies and others interested to clinically investigate and evaluate the efficacy of using low concentrations of iodine and the associated side effects.展开更多
Background Few studies have investigated the role of serum uric acid （SUA） on the risk of contrast-in- duced nephropathy（CIN） in patients with acute coronary syndrome （ACS） after emergent percutaneous coronary i...Background Few studies have investigated the role of serum uric acid （SUA） on the risk of contrast-in- duced nephropathy（CIN） in patients with acute coronary syndrome （ACS） after emergent percutaneous coronary intervention（PCI）. The present study was conducted to investigate the relationship between hyperuricemia （HUA） and CIN in patients after emergent PCI. Methods A total of 558 consecutive patients with ACS undergoing emergent PCI in Fujian Provincial Hospital were enrolled in this study. Patients were divided into hyperuricemic group （n=136） and normouricemic group （n=422）. Hyperuricemia was defined as SUA 〉420 μmol/L for male, 〉 360 txmol/L for female. CIN was defined as an absolute ≥44.2 μmol/L（0.5 mg/dL） increase inthe serum creati- nine （SCr） level within 72 hours after contrast medium exposure. In hospital incidences of CIN and the major adverse cardiac events were compared between the two groups. The relationship between the incidence of CIN and HUA was evaluated by multivariate logistic regression analysis. Results Among the 558 patients, CIN was observed in 34（6.1%） patients, and incidence of CIN was significantly higher in the HUA group than in the normou- ricemic group [13.2% （18/136） vs. 3.8%（16/422）, P 〈 0.001]. SUA concentration was significantly higher in CIN group compared with that in non - CIN group [ （490.21±76.48 μmol/L） vs. （307.00±65.37μmol/L）, P 〈 0.001]. Need for renal replacement therapy （RRT）, congestive heart failure （CHF）, in hospital mortality after PCI were significantly higher in the HUA group compared with Normouricemic group （all P〈0.05）. Patients who devel- oped CIN had higher in hospital mortality [44.1% （15/34） vs. 2.9 % （15/524）, P 〈 0.001 ]. Multivariate analysis in- dicates that HUA（OR=3.020, 95% CI： 1.3340- 6.805, P 〈 0.001）, Intra- aortic balloon pump （IABP） use （OR= 15.724,95% CI： 3.913-63.179, P 〈 0.001） and Perioperative hypotension（OR=3.342, 95% CI： 1.373-8.138, P 〈 0.01） were predictors of CIN in patients after emergent percutaneous coronary intervention. Conclusion Hyper- uricemia is the independent risk predictor of CIN in patients with ACS undergoing emergent PCI.展开更多
基金the National Key R&D Program of China(No.2017YFC1500100)National Natural Science Foundation of China(Nos.U1701641,41874052,41730211 and 41774049)+5 种基金Guangdong Province Introduced Innovative R&D Team(Nos.2017ZT07Z066 and 2016ZT06N331)Guangdong Science and Technology Plan Project(No.2017B030314082)Combination Project with Monitoring,Prediction and Scientific Research of Earthquake Technology,CEA(No.3JH-201901051)Seismic Regime Tracking Project of CEA(No.2020010111)Some figures were plotted with Generic Mapping Tools(Wessel and Smith,1995)The authors sincerely acknowledge the anonymous reviewers and journal editors for their help,support,checking and helpful comments to the manuscript.
文摘The P receiver function includes P-to-SV converted phases and multiple reverberations of the discontinuities in the crust and mantle.The time of these phases is related to the crustal thickness and vp/vs ratio,and the amplitude of these phases is mainly controlled by the velocity and density contrast of interfaces.By using H-κstacking method,this work estimated the crustal thickness and vP/vS ratio beneath the stations in the Guangdong province of South China.The velocity and density contrast(δβ-δρ)scanning stacking algorithm of the receiver function is applied to constrain the velocity and density contrast of the Moho in Guangdong province.This work analyzed the results of the crustal thickness,vp/vS ratio,and the velocity and density contrasts of Moho.The results indicate that the velocity contrast is higher beneath Yangjiang area in western Guangdong province and Nanao area in eastern Guangdong,which has a strong correlation with the distribution of geothermal springs in local areas and the characteristics of high heat flow.The velocity contrast of Moho has also a good correlation with the vP/vS ratio and the crustal thickness,which indicates that there is a strong material composition contrasts of the Moho in the study area.Velocity and density contrasts of Moho in some local area(such as western Guangdong)are somewhat consistent with the seismic activities.
文摘The purpose of this research is to investigate the feasibility of using low contrast agent concentration with X-ray computed tomography in visualizing and diagnosing the human vascular system while minimizing the risk of toxicity to the patient. This research investigated the effect of several iodine contrast agent concentrations on the ability to extract and visualize human vessels using simulated computed tomography scans. Monte Carlo simulation was used to perform these computed tomography acquisitions. The simulated patient was based on actual computed tomography angiography data, where a technique was developed to simulate brain vessels with contrast agents ranging from 0 mg to 20 mg of iodine. The simulation used segmented patient data along with basic image processing techniques to model the various levels of iodine concentrations. Cone beam computed tomography projections of a patient injected with and without iodine were acquired in the simulations. Subtraction of the corresponding projections was performed to generate images caused by the contrast agent. Then, histogram analysis of these differences was used to assess the validity of extracting and visualizing the human vessels. The smallest amount of iodine, 0.5 mg, helped better visualize the brain vessels and 2 mg of iodine was high enough to show almost 90% of the vessels. Additionally, the vessels were clearly visible in all the subtracted images. This research showed very promising outcomes in using low concentrations of iodine. Thus, this study proposes for the pharmaceutical companies and others interested to clinically investigate and evaluate the efficacy of using low concentrations of iodine and the associated side effects.
基金supported by the Youth project of Fujian provincial health and Family Planning Commission(No.2015-1-9)
文摘Background Few studies have investigated the role of serum uric acid （SUA） on the risk of contrast-in- duced nephropathy（CIN） in patients with acute coronary syndrome （ACS） after emergent percutaneous coronary intervention（PCI）. The present study was conducted to investigate the relationship between hyperuricemia （HUA） and CIN in patients after emergent PCI. Methods A total of 558 consecutive patients with ACS undergoing emergent PCI in Fujian Provincial Hospital were enrolled in this study. Patients were divided into hyperuricemic group （n=136） and normouricemic group （n=422）. Hyperuricemia was defined as SUA 〉420 μmol/L for male, 〉 360 txmol/L for female. CIN was defined as an absolute ≥44.2 μmol/L（0.5 mg/dL） increase inthe serum creati- nine （SCr） level within 72 hours after contrast medium exposure. In hospital incidences of CIN and the major adverse cardiac events were compared between the two groups. The relationship between the incidence of CIN and HUA was evaluated by multivariate logistic regression analysis. Results Among the 558 patients, CIN was observed in 34（6.1%） patients, and incidence of CIN was significantly higher in the HUA group than in the normou- ricemic group [13.2% （18/136） vs. 3.8%（16/422）, P 〈 0.001]. SUA concentration was significantly higher in CIN group compared with that in non - CIN group [ （490.21±76.48 μmol/L） vs. （307.00±65.37μmol/L）, P 〈 0.001]. Need for renal replacement therapy （RRT）, congestive heart failure （CHF）, in hospital mortality after PCI were significantly higher in the HUA group compared with Normouricemic group （all P〈0.05）. Patients who devel- oped CIN had higher in hospital mortality [44.1% （15/34） vs. 2.9 % （15/524）, P 〈 0.001 ]. Multivariate analysis in- dicates that HUA（OR=3.020, 95% CI： 1.3340- 6.805, P 〈 0.001）, Intra- aortic balloon pump （IABP） use （OR= 15.724,95% CI： 3.913-63.179, P 〈 0.001） and Perioperative hypotension（OR=3.342, 95% CI： 1.373-8.138, P 〈 0.01） were predictors of CIN in patients after emergent percutaneous coronary intervention. Conclusion Hyper- uricemia is the independent risk predictor of CIN in patients with ACS undergoing emergent PCI.
