For the recognition of high-resolution range profile (HRRP) in radar, the weighted HRRP can reduce the instability of range cells caused by the attitude change of targets. A novel approach is proposed to optimize th...For the recognition of high-resolution range profile (HRRP) in radar, the weighted HRRP can reduce the instability of range cells caused by the attitude change of targets. A novel approach is proposed to optimize the weighted HRRP. In the approach, the separability of weighted HRRPs in different targets is measured by de- signing an objective function, and the weighted coefficients are computed by using the gradient descent method, thus enhancing the influence of stable range cells. Simulation results based on five aircraft models show that the approach can effectively optimize the weighted HRRP and improve the recognition accuracy.展开更多
The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the ge...The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the genetic algorithm (GA) is investigated. Its calculation speed is faster than that of traditional optimization methods, and it is suitable for the machining parameter optimization in the automatic manufacturing system. Based on the theoretical studies, a system of machining parameter management and optimization is developed. The system can improve productivity of the high-speed machining centers.展开更多
The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the ...The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the turbulent coherent structure in the channel flow. Th is method contains three dimensional coupling difference scheme with high accur acy and high resolution, and the high order time splitting methods. Compared with the general spectral method, the method can be used to research turbule nt coherent structure under more general boundary conditions and in flow domains . In this paper, the generation and evolution of the turbulent coherent structur es ind uced by wall pulse in the channel flow are simulated, and the basic characterist ics and rules of the turbulent coherent structure are shown. Computational r esults indicate that a wall negative pulse is more convenient than the resonant three wave model.展开更多
Polishing is an important finishing process in die and mold manufacturing. Hand polishing takes long time and much labor. Efforts are made to automate the polishing process while keeping accuracy. Recently grinding ce...Polishing is an important finishing process in die and mold manufacturing. Hand polishing takes long time and much labor. Efforts are made to automate the polishing process while keeping accuracy. Recently grinding centers have been developed, which are used for free surface polishing in the present work. The new polishing technique applies the same cutting locus as used in the cutting process to remove only cusp height effectively, keeping the form accuracy generated in the cutting process.展开更多
We study a neutral donor center (D^0) and a negatively charged donor center (D^-) trapped by a quantum dot, which is subjected to a Gaussian potential confinement. Calculations are made by using the method of nume...We study a neutral donor center (D^0) and a negatively charged donor center (D^-) trapped by a quantum dot, which is subjected to a Gaussian potential confinement. Calculations are made by using the method of numerical diagonalization of Hamiltonian within the effective-mass approximation. The dependence of the ground state of the neutral shallow donor and the negatively charged donor on the dot size and the potential depth is investigated. The same calculations performed with the parabolic approximation of the Gaussian potential lead to the results that are qualitatively and quantitatively different from each other.展开更多
Background Cardiac implantable electronic devices (CIEDs) greatly improve survival and life quality of patients. However, there are gender differences regarding both the utilization and benefit of these devices. In ...Background Cardiac implantable electronic devices (CIEDs) greatly improve survival and life quality of patients. However, there are gender differences regarding both the utilization and benefit of these devices. In this prospective CIED registry, we aim to appraise the gender differences in CIED utilization in China. Methods Twenty centers from 14 provinces in China were included in our registry study. All patients who underwent a CIED implantation in these twenty centers between Jan 2015 and Dec 2016 were included. Results A total of 8570 patients were enrolled in the baseline cohort, including 7203 pacemaker, 664 implantable cardiac defibrillators (ICD) implants and 703 cardiac resynchronization therapy device (CRT/D). Totally, 4117 (48.0%) CIED patients were female, and more than 59% pacemaker patients were female, but women account only one third of ICD or CRT/D implantation in this registry. There were significant differences between genders at pacemaker and ICD indications. Female was more likely received a pacemaker due to sick sinus syndrome (SSS) (63.9% vs. 51.0%, P 〈 0.001). Female patients receiving an ICD were more likely due to cardiac ion channel disease (29.2% vs. 4.2%, P 〈 0.001). The percentage of utilization of dual-chamber pacemaker in female patients was significantly higher than male (85.3% vs. 81.1%, P 〈 0.001). But male patients were more likely received a cardiac resynchronization therapy devices with defibrillator than female (56.5% vs. 41.9%, P = 0.001). In pacemaker patient, male was more likely to have structure heart disease (31.3% vs. 28.0%, P = 0.002). In ICD patient, male patients were more likely to have ischemic heart disease (48.2% vs. 29.2%, P 〈 0.001). The mean age of women at the time of CRT/D implantation was older than men (P = 0.014). Nonischemic cardiomyopathy (70.9%) was the most common etiology in the patients who underwent the treat?ment of CRT/D, no matter male or female. Conclusions In real-world setting, female do have different epidemiology, pathophysiology and clinical presentation of many cardiac rhythm disorders when compared with male, and all these factors may affect the utilization of CIED implantation. But it also possibility that cultural and socioeconomic features may play a role in this apparent discrimination.展开更多
Objective To investigate the levels of cardiovascular disease risk factors and their relations to clinical phenotype associated with coronary artery disease(CAD).Methods The subjects were recruited from five independe...Objective To investigate the levels of cardiovascular disease risk factors and their relations to clinical phenotype associated with coronary artery disease(CAD).Methods The subjects were recruited from five independent cardiovascular centers.Coronary angiography was employed to define the CAD with stenosis in each major vessel ≥70% and control with stenosis <10% in every lesion.The classic risk factors including family history,body mass index,smoking habits,hypertension,diabetes mellitus,and serum lipid levels were surveyed according to established criteria.Associations between risk levels and clinical phenotypes were assessed by case control and correlation analysis.Results A total of 762 individuals were collected,including 481 men and 281 women,aged from 17 to 81(mean 60±10) years.The patients with CAD accounted for 55.5% of all participants,and controls 44.5%,respectively.Compared with the pattern in published data,our study showed that mean serum high density lipoprotein cholesterol(HDL-C) level was significantly lower(P<0.001) and triglycerides was significantly higher(P<0.001),while total cholesterol(TC) and low density lipoprotein cholesterol levels were comparative(both P>0.05).The prevalence of low HDL-C(<40 g/L) and hypertriglyceridemia(>150 g/L) were 27.2% and 41.4%,respectively.Mean serum levels of HDL-C and apolipoprotein A1 were significantly higher in female subjects than in male(P<0.001).Lower HDL-C functioned as an independent risk factor for CAD only in men(RR=2.8,95%CI:1.5-4.2,P<0.001),yet increased non-HDL cholesterol combined with diabetes mellitus and obesity seemed to play a key role in the development ofCAD in women.Similarity in risk association with CAD was found for hypertension and TC/HDL ratio in male and female subjects,while family history had no relationship with the presence of CAD.Conclusion It is remarkable that emphasis of intervention in future should be given on the prevalent low serum HDL-C and its strong risk correlation with the presence of CAD in male subjects of Chinese Han population.展开更多
Objective:To evaluate the effect and safety of clinical use of zoledronic acid in the treatment of malignant hypercalcemia.Methods:A multi-center,open phase II clinical trial was conducted in 15 cases with malignant h...Objective:To evaluate the effect and safety of clinical use of zoledronic acid in the treatment of malignant hypercalcemia.Methods:A multi-center,open phase II clinical trial was conducted in 15 cases with malignant hypercalcemia who received zoledronic acid intravenously for 15 min.The level of blood calcium and side effects were recorded regularly within 28 days after injection.Results:One case was dropped out due to bad compliance.The complete response rate(the corrected serum calcium was reduced to normal level)was 100.00%(14/14).The medium time of complete response rate was 5.07 days.The medium maintain time was 22.30 days.Slight,or moderate fever was observed.Conclusion:Zoledronic acid can effectively reduce the malignant hypercalcemia.The use of zoledronic acid appears to be safety and convenient.展开更多
1 Introduction Hypertension and cerebrovascular disease incidence and prevalence rise dramatically with age, owing to longer exposure time to age-associated alterations in vascular function and structure and cardiova...1 Introduction Hypertension and cerebrovascular disease incidence and prevalence rise dramatically with age, owing to longer exposure time to age-associated alterations in vascular function and structure and cardiovascular risk factors. This chapter is aimed at connecting age-related alterations in vascular function and structure to the resultant target organ damage, and to raise awareness of unique presentations and treatment strategies for hypertension and stroke in older adults.展开更多
Background Although angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) are equally important in the treatment of hypertension, there is less evidence whether they have equal ca...Background Although angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) are equally important in the treatment of hypertension, there is less evidence whether they have equal cardiovascular and cerebrovascular protective effects, especially in elder hypertensive patients. This study aims to clarify this unresolved issue. Methods This cross-sectional study included clinical data on 933 aged male patients with hypertension who received either an ARB or ACEI for more than two months between January 2007 and May 2011. The primary outcome was the composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke. The secondary endpoints were unstable angina, new atrial fibrillation, and transient ischemic attack. Results The median follow-up time was 24 months. Age, drug types, cerebral infarction history, renal dysfunction history were the independent predictors of the primary endpoint. The risk of an occurrence of a primary endpoint event was higher in the ARB group than the ACEI group [P = 0.037, hazard ratios (HR): 2.124, 95% confidence interval (95% CI): 1.048-4.306]. The Kaplan-Meier method also suggests that the rate of primary endpoint occurrence was higher in the ARB group than the ACEI group (P = 0.04). In regard to the secondary endpoints, there were no significant differences between the two treatment arms (P = 0.137, HR: 1.454, 95% CI: 0.888-2.380). Patient age and coronary heart disease history were independent predictors of the secondary endpoint. Conclusion ACEI were more effective than ARB in reducing cardiovascular and cerebrovascular morbidity and mortality in aged patients with hypertension.展开更多
Information-Centric Networking(ICN), an alternative architecture to the current Internet infrastructure, focuses on the distribution and retrieval of content by employing caches in a network to reduce network traffic....Information-Centric Networking(ICN), an alternative architecture to the current Internet infrastructure, focuses on the distribution and retrieval of content by employing caches in a network to reduce network traffic. The employment of caches may be accomplished using graph-based and content-based criteria such as the position of a node in a network and content popularity. The contribution of this paper lies on the characterization of content popularity for on-path in-network caching. To this end, four dynamic approaches for identifying content popularity are evaluated via simulations. Content popularity may be determined per chunk or per object, calculated by the number of requests for a content against the sum of requests or the maximum number of requests. Based on the results, chunk-based approaches provide 23% more accurate content popularity calculations than object-based approaches. In addition, approaches that are based on the comparison of a content against the maximum number of requests have been shown to be more accurate than the alternatives.展开更多
One of the most basic characteristics of photonic crystal is frequency band gap. When defects are introduced into the periodic photonic crystal, a number of defect modes appear in the stop band. In this paper, we expl...One of the most basic characteristics of photonic crystal is frequency band gap. When defects are introduced into the periodic photonic crystal, a number of defect modes appear in the stop band. In this paper, we exploit transfer matrix method based on photonic crystal theory, and assume the sampled fiber Bragg grating as one-dimensional dual photonic crystal with a large size defect. Characteristics of the sampled fiber Bragg grating are analyzed. Experimental results show that the sampled fiber Bragg grating has many reflective peaks. Its reflectivity, center wavelength, reflective peak intervals and band width all change with the grating parameters, including grating length, duty ratio of the material with high dielectric constant, and index modulation depth and period. Results agree with the conventional couple mode theory which can be used when analyzing other characteristics of the sampled fiber Bragg grating or applying it into practice.展开更多
This research investigated whether there was a significant relationship between the problems of loneliness, inferiority, and identity confusion. Also, to test whether there was a significant relationship between probl...This research investigated whether there was a significant relationship between the problems of loneliness, inferiority, and identity confusion. Also, to test whether there was a significant relationship between problems of adolescents and their ages and sexes and to ascertain whether there will be a significant difference in sex with regards to these problems, 240 adolescent students from four Senior High Schools were sampled as respondents for the study. Correlations and t-test were used for analyses by employing Statistical Package for Social Sciences (SPSS) version 16. From the results, it appeared that there were highly significant positive correlations existing between the problems. This suggests that the more an adolescent experiences a problem, the higher will he/she experience another problem. Also, it appeared that among the three problems, inferiority had a significant relationship with sex whereas all the problems had a positive significant relationship with age. This suggests that the older an adolescent is, the more severe will he/she experience a problem. Finally, girls tend to experience inferiority more than their male counterparts. This finding also suggested that although problems of adolescents may differ with regards to sex, they are not isolated and therefore multi-factorial in nature.展开更多
Objectives Although development of new treatment modalities limited digoxin usage, digoxin intoxication is still an important issue which could be easily overlooked. In this report, we analyzed a case series definitiv...Objectives Although development of new treatment modalities limited digoxin usage, digoxin intoxication is still an important issue which could be easily overlooked. In this report, we analyzed a case series definitively diagnosed as digoxin intoxication in the modern era. Methods We analyzed 71 patients hospitalized with digoxin intoxication confirmed by history, complaints, clinical and electrocardiograph (ECG) findings, and serum digoxin levels 〉 2.0 ng/mL, during a five year period. The demographic and clinical data, indications for digoxin use, digoxin dosage, concurrent medications, laboratory data, hospital monitoring, and ECG findings were obtained from all patients. Results Thirty-eight of 71 patients (53.5%) had symptoms of heart failure during admission or later. Sixty-four percent of patients were older than 75 years. The percentage of females was 67%. Atrial fibrillation, hypertension and gastrointestinal complaints were more frequent in the females (64% in females, 30% in males, P = 0.007; 81% in female, 52% in males, P = 0.01; 50% in female, 17.3% in males, P = 0.008, respectively). The mortality rate during the hospital course was 7%. Conclusions This report demonstrated the reduced mortality rates in patients with digoxin intoxication over the study period. Gastrointestinal complaints are the most common symptoms in this population.展开更多
Aiming at solving the problems such as time consuming and application limiting presented in the existing synchronous cooperative spectrum sensing schemes,a triggered asynchronous scheme based on Dempster-Shafer(D-S) t...Aiming at solving the problems such as time consuming and application limiting presented in the existing synchronous cooperative spectrum sensing schemes,a triggered asynchronous scheme based on Dempster-Shafer(D-S) theory was proposed.Sensing asynchronously,each cognitive user calculated the confidence measure functions with double threshold spectrum sensing method.When the useful report was received by the fusion center,a fusion process would be triggered.Then the sensing results were fused together based on D-S theory.The analysis and simulation results show that the proposed scheme can improve the spectrum sensing efficiency and reduce the calculation amount of the fusion center compared with the existing schemes.展开更多
IT as a dynamic filed changes very rapidly; efficient management of such systems for the most of the companies requires handling tremendous complex situations in terms of hardware and software setup. Hardware and soft...IT as a dynamic filed changes very rapidly; efficient management of such systems for the most of the companies requires handling tremendous complex situations in terms of hardware and software setup. Hardware and software itself changes quickly with the time and keeping them updated is a difficult problem for the most of the companies; the problem is more emphasized for the companies having large infrastructure of IT facilities such as data centers which are expensive to be maintained. Many applications run on the company premises which require well prepared staff for successfully maintaining them. With the inception of Cloud Computing many companies have transferred their applications and data into cloud computing based platforms in order to have reduced maintaining cost, easier maintenance in terms of hardware and software, reliable and securely accessible services. The benefits of building distributed applications using Google infrastructure are conferred in this paper.展开更多
The major source of loss in modem compressors is the secondary loss. Non-axisymmetric endwall profile contouring is now a well established design methodology in axial flow turbines. However, flow development in axial ...The major source of loss in modem compressors is the secondary loss. Non-axisymmetric endwall profile contouring is now a well established design methodology in axial flow turbines. However, flow development in axial compressors is differ from turbines, the effects of non-axisymmetric endwall to axial compressors requires flow analysis in detail. This paper presents both experimental and numerical data to deal with the application of a non-axisymmetric hub endwall in a high-subsonic axial-flow compressor. The aims of the experiment here were to make sure the numerically obtained flow fields is the physical mechanism responsible for the improvement in efficiency, due to the non-axisymmetric hub endwall. The computational results were first compared with avail- able measured data of axisymmetric hub endwall. The results agreed well with the experimental data for estima- tion of the global performance. The coupled flow of the compressor rotor with non-axisymmetric hub endwall was simulated by a state-of-the-art multi-block flow solver. The non-axisymmetric hub endwall was designed for a subsonic compressor rotor with the help of sine and cosine functions. This type of non-axisymmetric hub end- wall was found to have a significant improvement in efficiency of 0.45% approximately and a slightly increase for the total pressure ratio. The fundamental mechanisms of non-axisymmetric hub endwall and their effects on the subsonic axial-flow compressor endwall flow field were analyzed in detail. It is concluded that the non-axisymmetric endwall profiling, though not optimum, can mitigate the secondary flow in the vicinity of the hub endwall, resulting in the improvement of aerodynamic performance of the compressor rotor.展开更多
基金Supported by the Academician Foundation of the 14th Research Institute of China Electronics Technology Group Corporation(2008041001)~~
文摘For the recognition of high-resolution range profile (HRRP) in radar, the weighted HRRP can reduce the instability of range cells caused by the attitude change of targets. A novel approach is proposed to optimize the weighted HRRP. In the approach, the separability of weighted HRRPs in different targets is measured by de- signing an objective function, and the weighted coefficients are computed by using the gradient descent method, thus enhancing the influence of stable range cells. Simulation results based on five aircraft models show that the approach can effectively optimize the weighted HRRP and improve the recognition accuracy.
文摘The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the genetic algorithm (GA) is investigated. Its calculation speed is faster than that of traditional optimization methods, and it is suitable for the machining parameter optimization in the automatic manufacturing system. Based on the theoretical studies, a system of machining parameter management and optimization is developed. The system can improve productivity of the high-speed machining centers.
文摘The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the turbulent coherent structure in the channel flow. Th is method contains three dimensional coupling difference scheme with high accur acy and high resolution, and the high order time splitting methods. Compared with the general spectral method, the method can be used to research turbule nt coherent structure under more general boundary conditions and in flow domains . In this paper, the generation and evolution of the turbulent coherent structur es ind uced by wall pulse in the channel flow are simulated, and the basic characterist ics and rules of the turbulent coherent structure are shown. Computational r esults indicate that a wall negative pulse is more convenient than the resonant three wave model.
基金Project supported by the Natural Science Foundation of Shaanxi Province(Grant No.2006E112)
文摘Polishing is an important finishing process in die and mold manufacturing. Hand polishing takes long time and much labor. Efforts are made to automate the polishing process while keeping accuracy. Recently grinding centers have been developed, which are used for free surface polishing in the present work. The new polishing technique applies the same cutting locus as used in the cutting process to remove only cusp height effectively, keeping the form accuracy generated in the cutting process.
基金The project supported by National Natural Science Foundation of China under Grant No. 10475014 and the Natural Science Foundation of Guangdong Province under Grant No. 04009519
文摘We study a neutral donor center (D^0) and a negatively charged donor center (D^-) trapped by a quantum dot, which is subjected to a Gaussian potential confinement. Calculations are made by using the method of numerical diagonalization of Hamiltonian within the effective-mass approximation. The dependence of the ground state of the neutral shallow donor and the negatively charged donor on the dot size and the potential depth is investigated. The same calculations performed with the parabolic approximation of the Gaussian potential lead to the results that are qualitatively and quantitatively different from each other.
文摘Background Cardiac implantable electronic devices (CIEDs) greatly improve survival and life quality of patients. However, there are gender differences regarding both the utilization and benefit of these devices. In this prospective CIED registry, we aim to appraise the gender differences in CIED utilization in China. Methods Twenty centers from 14 provinces in China were included in our registry study. All patients who underwent a CIED implantation in these twenty centers between Jan 2015 and Dec 2016 were included. Results A total of 8570 patients were enrolled in the baseline cohort, including 7203 pacemaker, 664 implantable cardiac defibrillators (ICD) implants and 703 cardiac resynchronization therapy device (CRT/D). Totally, 4117 (48.0%) CIED patients were female, and more than 59% pacemaker patients were female, but women account only one third of ICD or CRT/D implantation in this registry. There were significant differences between genders at pacemaker and ICD indications. Female was more likely received a pacemaker due to sick sinus syndrome (SSS) (63.9% vs. 51.0%, P 〈 0.001). Female patients receiving an ICD were more likely due to cardiac ion channel disease (29.2% vs. 4.2%, P 〈 0.001). The percentage of utilization of dual-chamber pacemaker in female patients was significantly higher than male (85.3% vs. 81.1%, P 〈 0.001). But male patients were more likely received a cardiac resynchronization therapy devices with defibrillator than female (56.5% vs. 41.9%, P = 0.001). In pacemaker patient, male was more likely to have structure heart disease (31.3% vs. 28.0%, P = 0.002). In ICD patient, male patients were more likely to have ischemic heart disease (48.2% vs. 29.2%, P 〈 0.001). The mean age of women at the time of CRT/D implantation was older than men (P = 0.014). Nonischemic cardiomyopathy (70.9%) was the most common etiology in the patients who underwent the treat?ment of CRT/D, no matter male or female. Conclusions In real-world setting, female do have different epidemiology, pathophysiology and clinical presentation of many cardiac rhythm disorders when compared with male, and all these factors may affect the utilization of CIED implantation. But it also possibility that cultural and socioeconomic features may play a role in this apparent discrimination.
基金Supported by a grant from Desert Foundation (2003),Salt Lake City,USA
文摘Objective To investigate the levels of cardiovascular disease risk factors and their relations to clinical phenotype associated with coronary artery disease(CAD).Methods The subjects were recruited from five independent cardiovascular centers.Coronary angiography was employed to define the CAD with stenosis in each major vessel ≥70% and control with stenosis <10% in every lesion.The classic risk factors including family history,body mass index,smoking habits,hypertension,diabetes mellitus,and serum lipid levels were surveyed according to established criteria.Associations between risk levels and clinical phenotypes were assessed by case control and correlation analysis.Results A total of 762 individuals were collected,including 481 men and 281 women,aged from 17 to 81(mean 60±10) years.The patients with CAD accounted for 55.5% of all participants,and controls 44.5%,respectively.Compared with the pattern in published data,our study showed that mean serum high density lipoprotein cholesterol(HDL-C) level was significantly lower(P<0.001) and triglycerides was significantly higher(P<0.001),while total cholesterol(TC) and low density lipoprotein cholesterol levels were comparative(both P>0.05).The prevalence of low HDL-C(<40 g/L) and hypertriglyceridemia(>150 g/L) were 27.2% and 41.4%,respectively.Mean serum levels of HDL-C and apolipoprotein A1 were significantly higher in female subjects than in male(P<0.001).Lower HDL-C functioned as an independent risk factor for CAD only in men(RR=2.8,95%CI:1.5-4.2,P<0.001),yet increased non-HDL cholesterol combined with diabetes mellitus and obesity seemed to play a key role in the development ofCAD in women.Similarity in risk association with CAD was found for hypertension and TC/HDL ratio in male and female subjects,while family history had no relationship with the presence of CAD.Conclusion It is remarkable that emphasis of intervention in future should be given on the prevalent low serum HDL-C and its strong risk correlation with the presence of CAD in male subjects of Chinese Han population.
文摘Objective:To evaluate the effect and safety of clinical use of zoledronic acid in the treatment of malignant hypercalcemia.Methods:A multi-center,open phase II clinical trial was conducted in 15 cases with malignant hypercalcemia who received zoledronic acid intravenously for 15 min.The level of blood calcium and side effects were recorded regularly within 28 days after injection.Results:One case was dropped out due to bad compliance.The complete response rate(the corrected serum calcium was reduced to normal level)was 100.00%(14/14).The medium time of complete response rate was 5.07 days.The medium maintain time was 22.30 days.Slight,or moderate fever was observed.Conclusion:Zoledronic acid can effectively reduce the malignant hypercalcemia.The use of zoledronic acid appears to be safety and convenient.
文摘1 Introduction Hypertension and cerebrovascular disease incidence and prevalence rise dramatically with age, owing to longer exposure time to age-associated alterations in vascular function and structure and cardiovascular risk factors. This chapter is aimed at connecting age-related alterations in vascular function and structure to the resultant target organ damage, and to raise awareness of unique presentations and treatment strategies for hypertension and stroke in older adults.
文摘Background Although angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) are equally important in the treatment of hypertension, there is less evidence whether they have equal cardiovascular and cerebrovascular protective effects, especially in elder hypertensive patients. This study aims to clarify this unresolved issue. Methods This cross-sectional study included clinical data on 933 aged male patients with hypertension who received either an ARB or ACEI for more than two months between January 2007 and May 2011. The primary outcome was the composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke. The secondary endpoints were unstable angina, new atrial fibrillation, and transient ischemic attack. Results The median follow-up time was 24 months. Age, drug types, cerebral infarction history, renal dysfunction history were the independent predictors of the primary endpoint. The risk of an occurrence of a primary endpoint event was higher in the ARB group than the ACEI group [P = 0.037, hazard ratios (HR): 2.124, 95% confidence interval (95% CI): 1.048-4.306]. The Kaplan-Meier method also suggests that the rate of primary endpoint occurrence was higher in the ARB group than the ACEI group (P = 0.04). In regard to the secondary endpoints, there were no significant differences between the two treatment arms (P = 0.137, HR: 1.454, 95% CI: 0.888-2.380). Patient age and coronary heart disease history were independent predictors of the secondary endpoint. Conclusion ACEI were more effective than ARB in reducing cardiovascular and cerebrovascular morbidity and mortality in aged patients with hypertension.
基金funded by the Higher Education Authority (HEA)co-funded under the European Regional Development Fund (ERDF)
文摘Information-Centric Networking(ICN), an alternative architecture to the current Internet infrastructure, focuses on the distribution and retrieval of content by employing caches in a network to reduce network traffic. The employment of caches may be accomplished using graph-based and content-based criteria such as the position of a node in a network and content popularity. The contribution of this paper lies on the characterization of content popularity for on-path in-network caching. To this end, four dynamic approaches for identifying content popularity are evaluated via simulations. Content popularity may be determined per chunk or per object, calculated by the number of requests for a content against the sum of requests or the maximum number of requests. Based on the results, chunk-based approaches provide 23% more accurate content popularity calculations than object-based approaches. In addition, approaches that are based on the comparison of a content against the maximum number of requests have been shown to be more accurate than the alternatives.
文摘One of the most basic characteristics of photonic crystal is frequency band gap. When defects are introduced into the periodic photonic crystal, a number of defect modes appear in the stop band. In this paper, we exploit transfer matrix method based on photonic crystal theory, and assume the sampled fiber Bragg grating as one-dimensional dual photonic crystal with a large size defect. Characteristics of the sampled fiber Bragg grating are analyzed. Experimental results show that the sampled fiber Bragg grating has many reflective peaks. Its reflectivity, center wavelength, reflective peak intervals and band width all change with the grating parameters, including grating length, duty ratio of the material with high dielectric constant, and index modulation depth and period. Results agree with the conventional couple mode theory which can be used when analyzing other characteristics of the sampled fiber Bragg grating or applying it into practice.
文摘This research investigated whether there was a significant relationship between the problems of loneliness, inferiority, and identity confusion. Also, to test whether there was a significant relationship between problems of adolescents and their ages and sexes and to ascertain whether there will be a significant difference in sex with regards to these problems, 240 adolescent students from four Senior High Schools were sampled as respondents for the study. Correlations and t-test were used for analyses by employing Statistical Package for Social Sciences (SPSS) version 16. From the results, it appeared that there were highly significant positive correlations existing between the problems. This suggests that the more an adolescent experiences a problem, the higher will he/she experience another problem. Also, it appeared that among the three problems, inferiority had a significant relationship with sex whereas all the problems had a positive significant relationship with age. This suggests that the older an adolescent is, the more severe will he/she experience a problem. Finally, girls tend to experience inferiority more than their male counterparts. This finding also suggested that although problems of adolescents may differ with regards to sex, they are not isolated and therefore multi-factorial in nature.
文摘Objectives Although development of new treatment modalities limited digoxin usage, digoxin intoxication is still an important issue which could be easily overlooked. In this report, we analyzed a case series definitively diagnosed as digoxin intoxication in the modern era. Methods We analyzed 71 patients hospitalized with digoxin intoxication confirmed by history, complaints, clinical and electrocardiograph (ECG) findings, and serum digoxin levels 〉 2.0 ng/mL, during a five year period. The demographic and clinical data, indications for digoxin use, digoxin dosage, concurrent medications, laboratory data, hospital monitoring, and ECG findings were obtained from all patients. Results Thirty-eight of 71 patients (53.5%) had symptoms of heart failure during admission or later. Sixty-four percent of patients were older than 75 years. The percentage of females was 67%. Atrial fibrillation, hypertension and gastrointestinal complaints were more frequent in the females (64% in females, 30% in males, P = 0.007; 81% in female, 52% in males, P = 0.01; 50% in female, 17.3% in males, P = 0.008, respectively). The mortality rate during the hospital course was 7%. Conclusions This report demonstrated the reduced mortality rates in patients with digoxin intoxication over the study period. Gastrointestinal complaints are the most common symptoms in this population.
基金Science and Technology Projects of Xuzhou City,China(No.XX10A001)Jiangsu Provincial National Natural Science Foundation of China(No:BK20130199)
文摘Aiming at solving the problems such as time consuming and application limiting presented in the existing synchronous cooperative spectrum sensing schemes,a triggered asynchronous scheme based on Dempster-Shafer(D-S) theory was proposed.Sensing asynchronously,each cognitive user calculated the confidence measure functions with double threshold spectrum sensing method.When the useful report was received by the fusion center,a fusion process would be triggered.Then the sensing results were fused together based on D-S theory.The analysis and simulation results show that the proposed scheme can improve the spectrum sensing efficiency and reduce the calculation amount of the fusion center compared with the existing schemes.
文摘IT as a dynamic filed changes very rapidly; efficient management of such systems for the most of the companies requires handling tremendous complex situations in terms of hardware and software setup. Hardware and software itself changes quickly with the time and keeping them updated is a difficult problem for the most of the companies; the problem is more emphasized for the companies having large infrastructure of IT facilities such as data centers which are expensive to be maintained. Many applications run on the company premises which require well prepared staff for successfully maintaining them. With the inception of Cloud Computing many companies have transferred their applications and data into cloud computing based platforms in order to have reduced maintaining cost, easier maintenance in terms of hardware and software, reliable and securely accessible services. The benefits of building distributed applications using Google infrastructure are conferred in this paper.
基金Financial supports for the work presented are provided by National Natural Science Foundation of China (Project No: 50806073)China Postdoctoral Science Foundation (Project No: 20070420068)K C Wong Education Foundation, these supports are greatly appreciated
文摘The major source of loss in modem compressors is the secondary loss. Non-axisymmetric endwall profile contouring is now a well established design methodology in axial flow turbines. However, flow development in axial compressors is differ from turbines, the effects of non-axisymmetric endwall to axial compressors requires flow analysis in detail. This paper presents both experimental and numerical data to deal with the application of a non-axisymmetric hub endwall in a high-subsonic axial-flow compressor. The aims of the experiment here were to make sure the numerically obtained flow fields is the physical mechanism responsible for the improvement in efficiency, due to the non-axisymmetric hub endwall. The computational results were first compared with avail- able measured data of axisymmetric hub endwall. The results agreed well with the experimental data for estima- tion of the global performance. The coupled flow of the compressor rotor with non-axisymmetric hub endwall was simulated by a state-of-the-art multi-block flow solver. The non-axisymmetric hub endwall was designed for a subsonic compressor rotor with the help of sine and cosine functions. This type of non-axisymmetric hub end- wall was found to have a significant improvement in efficiency of 0.45% approximately and a slightly increase for the total pressure ratio. The fundamental mechanisms of non-axisymmetric hub endwall and their effects on the subsonic axial-flow compressor endwall flow field were analyzed in detail. It is concluded that the non-axisymmetric endwall profiling, though not optimum, can mitigate the secondary flow in the vicinity of the hub endwall, resulting in the improvement of aerodynamic performance of the compressor rotor.