Objective: Clopidogrel therapy is the standard of care in patients with unstable angina. However, a percentage of subjects are nonresponders to clopidogrel and this leads to increased adverse outcome. On the other way...Objective: Clopidogrel therapy is the standard of care in patients with unstable angina. However, a percentage of subjects are nonresponders to clopidogrel and this leads to increased adverse outcome. On the other way round, some responsive patients are exposed to bleeding complications. Detection of both in daily practice is important in order to tailor the treatment protocol. In this study we aimed to estimate the cutoff value of mean platelet volume (MPV) for both platelet responsiveness and bleeding risks. Methods: The study was planned as a prospective cohort study. A total number of 230 patients admitted to our CCU with unstable angina over a period of one year (from June 2013 to May 2014) were enrolled. Exclusion criteria were: severe anemia, throm-bocytopenia, myelodysplastic syndrome, coagulopathy and recent blood transfusion. In all patients clopidogrel was initially started and maintained during the hospital stay. Blood (2 ml) was collected in dipotassium EDTA tubes from all patients on the first day of admission by a clean puncture. Samples for MPV analysis were drawn on admission, and analyzed within 1 hour of admission after sampling by Beckman Caulter LH 780 Analyzer. Grouping was then done according to MPV of the patients into group (I) who had a low MPV less than or equal to 7.00 fl, and group (II) with MPV equal to or higher than 9.00 fl. Demographical and clinical variables of the patients were recorded. Routine laboratory parameters were also recorded. Clinical manifestations during the admission period were meticulously reported. Major complications as bleeding or, urgent need for percutaneous coronary intervention (PCI) were also studied. Results: Among the 230 patients analyzed, 175 patients (76%) were found to have MPV ≤7.00 fl (group (I)) and 55 patients (24%) had MPV ≥9.00 fl (group (II)) with mean ± SD MPV (8.4 ± 1.5 fl, vs 11.7 ± 1.2 fl respectively) (p < 0.001). Observation of clinical course during admission period revealed a statistically more significant clinical deteriorati展开更多
Load and resistance factors are generally obtained using the first order reliability method(FORM)in which the design point should be determined and derivative-based iterations used.In this article,the thirdmoment reli...Load and resistance factors are generally obtained using the first order reliability method(FORM)in which the design point should be determined and derivative-based iterations used.In this article,the thirdmoment reliability index,based on the three-parameter lognormal(3P-lognormal)distribution,is investigated.A simple method based on the third-moment method for estimating load and resistance factors is then proposed,and a simple formula for the target mean resistance is also presented to avoid iterative computations.Unlike the currently used method,the proposed method can be used to determine load and resistance factors,even when the probability density functions(PDFs)of the basic random variables are not available.Moreover,the proposed method does not require the iterative computation of derivatives or any design points.Thus,the method provides a more convenient and effective way to estimate load and resistance factors in practical engineering applications.Numerical examples are presented to demonstrate the advantages of the proposed third moment method for determining load and resistance factors.展开更多
Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured ...Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth （MPD） or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which also causes disruption of traffic in use. In this research skid numbers and MPD from 5 new asphalt pavements and 4 old asphalt pavements were collected using a locked wheel skid trailer and a vehicle mounted laser. Using the data collected, a correlation between the skid number （SN40R） collected by locked wheel skid tester and the texture data or MPD collected by a vehicle mounted laser operating at highway speeds was developed. The proposed correlation for new pavements was positive for MPD values less than 0.75 mm to reach a peak SN40R value, then there was a negative correlation as the MPD increases until the MPD value was equal to 1.1 mm and beyond the MPD value of 1.1 mm to the maximum value of 1.4 mm, SN40R value remained almost constant. There were significant data scatter for the MPD value of 0.8 mm. To explain these results, water film thickness during the friction test was calculated and the critical MPD was defined. The effect of sealed water pool on the SN40R was discussed. The test result showed a similar trend for older asphalt pavements, but with lower SN40R values due to the polishing of pavement micro-texture by traffic. Hence, a reduction factor was proposed for older pavements based on cumulative traffic volume for the above correlation to predict the skid resistance of older pavements.展开更多
A new concept of pseudo mean wave resistance is introduced to find theoretical mean wave resistances of the precursor soliton generation in two-layer how over a localized topography at near-resonance in this paper. Th...A new concept of pseudo mean wave resistance is introduced to find theoretical mean wave resistances of the precursor soliton generation in two-layer how over a localized topography at near-resonance in this paper. The pseudo mean wave resistance of the precursor soliton generation of two-layer how is determined in terms of the AfKdV equation. From the theoretical results it is shown that the theoretical mean wave resistance is equal to the pseudo mean wave resistance times 1/m(1), where m(1) is the coefficient of the fKdV equation. From the regional distribution of the energy of the precursor soliton generation at the resonant points, it is shown that ratios of the theoretical mean wave resistance and regional mean energy to the total mean energy are invariant constants, i.e. <(E)over circle (1)>/(E) over circle : <(E)over circle (2)>/(E) over circle: <(E)over circle (3)>(E) over circle :< D > /(E) over circle = (1/2) : (-1/2) : 1 : 1, in which <(E)over circle 1>,<(E)over circle (2)> and <(E)over circle (3)> are the mean energy of the generating regions of the precursor solitons, of the depression and of the trailing wavetrain at the resonant points respectively, (E) over circle and < D > are the total energy of the system and the theoretical mean wave resistance at the resonant points. A prediction of the theoretical mean wave resistances of two-layer how over the semicircular topography is carried out in terms of the theoretical results of the present paper. The comparison shows that the theoretical mean wave resistance is in good agreement with the numerical calculation.展开更多
文摘Objective: Clopidogrel therapy is the standard of care in patients with unstable angina. However, a percentage of subjects are nonresponders to clopidogrel and this leads to increased adverse outcome. On the other way round, some responsive patients are exposed to bleeding complications. Detection of both in daily practice is important in order to tailor the treatment protocol. In this study we aimed to estimate the cutoff value of mean platelet volume (MPV) for both platelet responsiveness and bleeding risks. Methods: The study was planned as a prospective cohort study. A total number of 230 patients admitted to our CCU with unstable angina over a period of one year (from June 2013 to May 2014) were enrolled. Exclusion criteria were: severe anemia, throm-bocytopenia, myelodysplastic syndrome, coagulopathy and recent blood transfusion. In all patients clopidogrel was initially started and maintained during the hospital stay. Blood (2 ml) was collected in dipotassium EDTA tubes from all patients on the first day of admission by a clean puncture. Samples for MPV analysis were drawn on admission, and analyzed within 1 hour of admission after sampling by Beckman Caulter LH 780 Analyzer. Grouping was then done according to MPV of the patients into group (I) who had a low MPV less than or equal to 7.00 fl, and group (II) with MPV equal to or higher than 9.00 fl. Demographical and clinical variables of the patients were recorded. Routine laboratory parameters were also recorded. Clinical manifestations during the admission period were meticulously reported. Major complications as bleeding or, urgent need for percutaneous coronary intervention (PCI) were also studied. Results: Among the 230 patients analyzed, 175 patients (76%) were found to have MPV ≤7.00 fl (group (I)) and 55 patients (24%) had MPV ≥9.00 fl (group (II)) with mean ± SD MPV (8.4 ± 1.5 fl, vs 11.7 ± 1.2 fl respectively) (p < 0.001). Observation of clinical course during admission period revealed a statistically more significant clinical deteriorati
基金This study was supported by the National Natural Science Foundation of China(Grant No.51008313)the Sheng-hua Lie-ying Program of Central South University,a grant from the National High Technology Research and Development Program of China(863 Program,No.2009AA11Z101)the Joint Research Fund for Overseas Chinese,Hong Kong and Macao Young Scholars(No.50828801)from the National Natural Science Foundation of China。
文摘Load and resistance factors are generally obtained using the first order reliability method(FORM)in which the design point should be determined and derivative-based iterations used.In this article,the thirdmoment reliability index,based on the three-parameter lognormal(3P-lognormal)distribution,is investigated.A simple method based on the third-moment method for estimating load and resistance factors is then proposed,and a simple formula for the target mean resistance is also presented to avoid iterative computations.Unlike the currently used method,the proposed method can be used to determine load and resistance factors,even when the probability density functions(PDFs)of the basic random variables are not available.Moreover,the proposed method does not require the iterative computation of derivatives or any design points.Thus,the method provides a more convenient and effective way to estimate load and resistance factors in practical engineering applications.Numerical examples are presented to demonstrate the advantages of the proposed third moment method for determining load and resistance factors.
基金sponsored by a research contract from the New Jersey Department of Transportation (FHWA-NJ-2009020)
文摘Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth （MPD） or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which also causes disruption of traffic in use. In this research skid numbers and MPD from 5 new asphalt pavements and 4 old asphalt pavements were collected using a locked wheel skid trailer and a vehicle mounted laser. Using the data collected, a correlation between the skid number （SN40R） collected by locked wheel skid tester and the texture data or MPD collected by a vehicle mounted laser operating at highway speeds was developed. The proposed correlation for new pavements was positive for MPD values less than 0.75 mm to reach a peak SN40R value, then there was a negative correlation as the MPD increases until the MPD value was equal to 1.1 mm and beyond the MPD value of 1.1 mm to the maximum value of 1.4 mm, SN40R value remained almost constant. There were significant data scatter for the MPD value of 0.8 mm. To explain these results, water film thickness during the friction test was calculated and the critical MPD was defined. The effect of sealed water pool on the SN40R was discussed. The test result showed a similar trend for older asphalt pavements, but with lower SN40R values due to the polishing of pavement micro-texture by traffic. Hence, a reduction factor was proposed for older pavements based on cumulative traffic volume for the above correlation to predict the skid resistance of older pavements.
基金The project supported by the Foundation of The State Education Commission"The Dynamics of Upper Ocean"and the Grants of The Physical Oceanography Laboratory of Ocean University of Qingdao
文摘A new concept of pseudo mean wave resistance is introduced to find theoretical mean wave resistances of the precursor soliton generation in two-layer how over a localized topography at near-resonance in this paper. The pseudo mean wave resistance of the precursor soliton generation of two-layer how is determined in terms of the AfKdV equation. From the theoretical results it is shown that the theoretical mean wave resistance is equal to the pseudo mean wave resistance times 1/m(1), where m(1) is the coefficient of the fKdV equation. From the regional distribution of the energy of the precursor soliton generation at the resonant points, it is shown that ratios of the theoretical mean wave resistance and regional mean energy to the total mean energy are invariant constants, i.e. <(E)over circle (1)>/(E) over circle : <(E)over circle (2)>/(E) over circle: <(E)over circle (3)>(E) over circle :< D > /(E) over circle = (1/2) : (-1/2) : 1 : 1, in which <(E)over circle 1>,<(E)over circle (2)> and <(E)over circle (3)> are the mean energy of the generating regions of the precursor solitons, of the depression and of the trailing wavetrain at the resonant points respectively, (E) over circle and < D > are the total energy of the system and the theoretical mean wave resistance at the resonant points. A prediction of the theoretical mean wave resistances of two-layer how over the semicircular topography is carried out in terms of the theoretical results of the present paper. The comparison shows that the theoretical mean wave resistance is in good agreement with the numerical calculation.
