This study examined the effect of different b values on diffusion-weighted MR imaging (DWI) of human prostate by using single-shot spin echo echo planar imaging (SE-EPI) sequences, observed the normal appearances ...This study examined the effect of different b values on diffusion-weighted MR imaging (DWI) of human prostate by using single-shot spin echo echo planar imaging (SE-EPI) sequences, observed the normal appearances and measured apparent diffusion coefficient (ADC) values in anatomical regions of normal prostate. Twenty-four healthy volunteers (mean age: 32 y) were studied by using a 1.5T system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm2. The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e., the peripheral zone (PZ), which exhibited higher signal intensity, and the central gland (CG). Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were (1.27±0.22)×10-3 mm2/s and (1.01±0.17)×10-3 mm2/s,respectively. The ADC values were found to be significantly higher in PZ than in CG (P〈0.05, paired t-test). Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.展开更多
A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sampl...A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sample with compressive en echelon faults changes into a tensile one after interchange occurs between stress axis σ1 and σ2. A similar experiment is observed when the sample with tensile en echelon faults changes into that with a bend fault after two segments of the en echelon fault linking up. These facts indicate that the variation of b value may con-tain the information of the regional dominant structural model. Therefore, b-value analyses could be a new method for studying regional dominant structural models.展开更多
The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In t...The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In this case,the combination structure variation between earthquake magnitudes and corresponding frequencies could be shown clearly. According to the calculation and analysis for limited mainshocks in the complete seismicity data of selected monitored area with assigned consistent lowest magnitude, the precursor anomaly features, quantitative indexes and the calculation formula of relative subject function of b value variation have been preliminarily worked out. The prediction in short period (from 1 to 3 months) for damage earthquakes in the monitored area mentioned above can be put forward on the basis of the results of quantitative calculation and analysis.展开更多
This paper points out that it is theoretically wrong for the traditional method to determine cumulatiove b value using linear regression and derive earthquake recurrence relation according to probability distribution ...This paper points out that it is theoretically wrong for the traditional method to determine cumulatiove b value using linear regression and derive earthquake recurrence relation according to probability distribution or density function. As a result, it always systematically overestimated b value so as to underestimate the frequencies of the part of larger earthquakes. The smaller the actual b in the research area, or the smaller the magnitude range of the data in regression, or the smaller the magnitude interval, the larger the above deviation. So for an area with lower upper bound magnitude, if only historic earthquake data are used to determine b value by regression method, the b value will be obviously overestimated and systematic deviation of seismic hazard will be arised because the lower bound magnitude of reliable data is high and the magnitude range of data is small. In this paper, it is suggested to substitude cumulative b value without upper bound magnitude for conventional cumulative b value with upper bound magnitude, and the regression method is devloped to determine b value without upper bound magnitude.展开更多
The earthquake size distribution is generally considered to obey the Gutenberg Richter (GR) law. We have introduced the concept of the b value spectrum based on the moment method to investigate the deviation of t...The earthquake size distribution is generally considered to obey the Gutenberg Richter (GR) law. We have introduced the concept of the b value spectrum based on the moment method to investigate the deviation of the actual magnitude distribution of earthquakes from this law. This enables us to describe characteristic features of the magnitude frequency distribution of earthquakes. We found also a simple relation between the η value and the b value spectrum. Analysis using this scheme showed that the actual size distributions of earthquakes have large variations from case to case and sometimes deviate considerably from the widely assumed the GR formula.展开更多
To take the seismic zone that includes the great shock with M S8.5 as the statistical unit of estimating b value can often lead to more large variance, because the seismogenic zone of the great shock with M...To take the seismic zone that includes the great shock with M S8.5 as the statistical unit of estimating b value can often lead to more large variance, because the seismogenic zone of the great shock with M S8.5 are larger than that delineated in general seismic zone. Two-level statistical units are considered in this paper. The seismic province is the first level unit that is suitable for group of earthquakes including the great shock of M S8.5. A seismic province can be divided into several seismic zones. They can be taken as the second level unit for group of quakes in which the super magnitude of the greatest shock do not exceed 8. Because of the nonstationarity in time of seismic activity, the unbalancedness of data and differential of seismic temporal series feature in different areas need to be considered when we select the time period for estimating b value. According to local conditions, the time period is selected at one′s discretion in order to reflect seismicity level of this statistical unit in future 100 years.展开更多
The G R relation lg N=a-bM( 1954)is an empirical formula used widely in the seismicity research. But the linearity of b curves has great difference in different time and space domains. An interested question in...The G R relation lg N=a-bM( 1954)is an empirical formula used widely in the seismicity research. But the linearity of b curves has great difference in different time and space domains. An interested question in this paper is that in how large a space time strength domain the b value has certain physical connotation. This study told us that we can get optimal statistical results of b value in those space time domains which can develop correspondent strong shocks with magnitude interval( M S≥8.5, 8.0≤ M S<8.5, 7.0≤ M S<8.0). Thus, the possible seismogenic areas in which strong shocks with different magnitude intervals develop can be inferred in different regions of the mainland of China. Finally, some new problems are proposed, such as the delimitation of seismic province, the seismicity parameter determination in seismic hazard analysis and in earthquake predictions by using b value.展开更多
Objective To investigate the value of BT-H3 in expressed prostatic secretions ( EPS) in differential diagnosis of patients with inflammatory elevation of PSA in t - PSA gray zone ( 4 - 10 ng /ml) . Methods One hundred...Objective To investigate the value of BT-H3 in expressed prostatic secretions ( EPS) in differential diagnosis of patients with inflammatory elevation of PSA in t - PSA gray zone ( 4 - 10 ng /ml) . Methods One hundred and sixteen patients from ages of 19 to 80 years ( mean,40 years) were studied. In the group there展开更多
Effects of Al(Ⅲ) concentration and pH on the speciation of Al(Ⅲ) in polyaluminum chloride (PACl) solutions especially on the Al13 fraction were investigated. A series of PACl samples were prepared over the ran...Effects of Al(Ⅲ) concentration and pH on the speciation of Al(Ⅲ) in polyaluminum chloride (PACl) solutions especially on the Al13 fraction were investigated. A series of PACl samples were prepared over the range of Al(Ⅲ) concentration from 0.01 to 2.0 mol/L with the B (OH/Al ratio) value from 1.0 to 2.5 by forced hydrolysis of AICl3. The samples were characterized by ferron assay, pH and 27^Al NMR. It was shown that the Al(Ⅲ) concentration had a dramatic effect on the hydrolysis processes and the species distribution of PACl was in relate to the decrease of pH. The fraction of Al species, Alb (or Al13) decreased and Al0 increased with increase of total Al(Ⅲ) concentration. Under the condition of Al(Ⅲ) 2.0 reel/L, B = 2.5, the pH value was 2.73 and no Al13 could be detected. During diluting and aging, the species distribution evoIved. The Al13 could then be detected again and the amounts increased with time. If the diluted samples were concentrated by freeze dry at -35℃ or heating at 80℃, the pH value and Al13 content would decrease with the increased concentration. It demonstrated that the key factor for formation of Al13 in concentrated PACl was pH value.展开更多
Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepat...Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions.展开更多
The influence of non-uniqueness in selecting statistical time ranges on seismicity parameters of b value and annual mean occurrence rate ν4 is widely analyzed and studied. The studied result states that the influence...The influence of non-uniqueness in selecting statistical time ranges on seismicity parameters of b value and annual mean occurrence rate ν4 is widely analyzed and studied. The studied result states that the influence of statistical time range on the b value is generally smaller than on the annual mean rate. Owing to the exponentially functional relation between the annual mean rate and b value, the variation of b value by varying statistical time range brings about decrease or increase in the annual mean rates of each magnitude interval with power progression law. These results will exert a synthetic effect on seismic safety evaluation results in various regions in our country.展开更多
Objective To analyze the serum keratin 18(K18)level of patients with hepatitis B virus(HBV)-related acute-on-chronic liver failure(HBV-ACLF)and its correlation with prognosis.Methods From December 2012 to October 2014...Objective To analyze the serum keratin 18(K18)level of patients with hepatitis B virus(HBV)-related acute-on-chronic liver failure(HBV-ACLF)and its correlation with prognosis.Methods From December 2012 to October 2014,120 patients who visited Fuzhou Infectious Diseases Hospital and were diagnosed with HBV-ACLF were enrolled,and 20 chronic hepatitis B(CHB)pa-展开更多
The properties of the ground and excited-state(γ-and β-bands) of ^168-178 Hf nuclei have been studied.The ratio r(I +2/I) and Eγ(I→I-2)/I have been calculated as a function of the spin(I) to determine the...The properties of the ground and excited-state(γ-and β-bands) of ^168-178 Hf nuclei have been studied.The ratio r(I +2/I) and Eγ(I→I-2)/I have been calculated as a function of the spin(I) to determine the groundstate evolution. The results indicate that these isotopes have a rotational property SU(3). The energy levels for the ground-state, γ-and β-bands of ^168-178 Hf have been calculated using the Interacting Boson Model and Semi Empirical Formula(SEF). The parameters of the best fit to the measured data are determined. The behavior of energy and B(E2) ratios in the ground state band are examined.展开更多
The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model(IBM-1). Predictions are given for the excited state energies...The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model(IBM-1). Predictions are given for the excited state energies for the ground state, β and γ-bands, the transition probabilities between these states, the rotational moment of inertia, and the energy staggering in the γ-band energies. The results of these calculations are compared with the experimental data on these isotopes.展开更多
The Generalized Collective Model (GCM) is applied to the even even neutron rich 104,106,108 Mo isotopes. With GCM the energy spectra, absolute B(E2) values, some B(E2) branching ratios and Potential Energy ...The Generalized Collective Model (GCM) is applied to the even even neutron rich 104,106,108 Mo isotopes. With GCM the energy spectra, absolute B(E2) values, some B(E2) branching ratios and Potential Energy Surfaces (PES) for the 104,106,108 Mo isotopes are calculated. The PES of all these isotopes show a prolate minimum which becomes more pronounced in 106 Mo. The results are in agreement with the recent experimental report but are different from the viewpoint of the triaxial rotors, or γ soft deformation. Through a systematic study of PES, it is suggested that the even even neutron rich 104,106,108 Mo isotopes have prolate deformation.展开更多
基金supported by a grant from Key Project of Science and Technology Research of Hubei Province of China (No. 2005AA304B08).
文摘This study examined the effect of different b values on diffusion-weighted MR imaging (DWI) of human prostate by using single-shot spin echo echo planar imaging (SE-EPI) sequences, observed the normal appearances and measured apparent diffusion coefficient (ADC) values in anatomical regions of normal prostate. Twenty-four healthy volunteers (mean age: 32 y) were studied by using a 1.5T system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm2. The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e., the peripheral zone (PZ), which exhibited higher signal intensity, and the central gland (CG). Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were (1.27±0.22)×10-3 mm2/s and (1.01±0.17)×10-3 mm2/s,respectively. The ADC values were found to be significantly higher in PZ than in CG (P〈0.05, paired t-test). Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.
基金National Natural Science Foundation of China (Grant No. 40072067) and Minister of Science and Technology of China (2004BA601B01).
文摘A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sample with compressive en echelon faults changes into a tensile one after interchange occurs between stress axis σ1 and σ2. A similar experiment is observed when the sample with tensile en echelon faults changes into that with a bend fault after two segments of the en echelon fault linking up. These facts indicate that the variation of b value may con-tain the information of the regional dominant structural model. Therefore, b-value analyses could be a new method for studying regional dominant structural models.
文摘The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In this case,the combination structure variation between earthquake magnitudes and corresponding frequencies could be shown clearly. According to the calculation and analysis for limited mainshocks in the complete seismicity data of selected monitored area with assigned consistent lowest magnitude, the precursor anomaly features, quantitative indexes and the calculation formula of relative subject function of b value variation have been preliminarily worked out. The prediction in short period (from 1 to 3 months) for damage earthquakes in the monitored area mentioned above can be put forward on the basis of the results of quantitative calculation and analysis.
文摘This paper points out that it is theoretically wrong for the traditional method to determine cumulatiove b value using linear regression and derive earthquake recurrence relation according to probability distribution or density function. As a result, it always systematically overestimated b value so as to underestimate the frequencies of the part of larger earthquakes. The smaller the actual b in the research area, or the smaller the magnitude range of the data in regression, or the smaller the magnitude interval, the larger the above deviation. So for an area with lower upper bound magnitude, if only historic earthquake data are used to determine b value by regression method, the b value will be obviously overestimated and systematic deviation of seismic hazard will be arised because the lower bound magnitude of reliable data is high and the magnitude range of data is small. In this paper, it is suggested to substitude cumulative b value without upper bound magnitude for conventional cumulative b value with upper bound magnitude, and the regression method is devloped to determine b value without upper bound magnitude.
文摘The earthquake size distribution is generally considered to obey the Gutenberg Richter (GR) law. We have introduced the concept of the b value spectrum based on the moment method to investigate the deviation of the actual magnitude distribution of earthquakes from this law. This enables us to describe characteristic features of the magnitude frequency distribution of earthquakes. We found also a simple relation between the η value and the b value spectrum. Analysis using this scheme showed that the actual size distributions of earthquakes have large variations from case to case and sometimes deviate considerably from the widely assumed the GR formula.
文摘To take the seismic zone that includes the great shock with M S8.5 as the statistical unit of estimating b value can often lead to more large variance, because the seismogenic zone of the great shock with M S8.5 are larger than that delineated in general seismic zone. Two-level statistical units are considered in this paper. The seismic province is the first level unit that is suitable for group of earthquakes including the great shock of M S8.5. A seismic province can be divided into several seismic zones. They can be taken as the second level unit for group of quakes in which the super magnitude of the greatest shock do not exceed 8. Because of the nonstationarity in time of seismic activity, the unbalancedness of data and differential of seismic temporal series feature in different areas need to be considered when we select the time period for estimating b value. According to local conditions, the time period is selected at one′s discretion in order to reflect seismicity level of this statistical unit in future 100 years.
文摘The G R relation lg N=a-bM( 1954)is an empirical formula used widely in the seismicity research. But the linearity of b curves has great difference in different time and space domains. An interested question in this paper is that in how large a space time strength domain the b value has certain physical connotation. This study told us that we can get optimal statistical results of b value in those space time domains which can develop correspondent strong shocks with magnitude interval( M S≥8.5, 8.0≤ M S<8.5, 7.0≤ M S<8.0). Thus, the possible seismogenic areas in which strong shocks with different magnitude intervals develop can be inferred in different regions of the mainland of China. Finally, some new problems are proposed, such as the delimitation of seismic province, the seismicity parameter determination in seismic hazard analysis and in earthquake predictions by using b value.
文摘Objective To investigate the value of BT-H3 in expressed prostatic secretions ( EPS) in differential diagnosis of patients with inflammatory elevation of PSA in t - PSA gray zone ( 4 - 10 ng /ml) . Methods One hundred and sixteen patients from ages of 19 to 80 years ( mean,40 years) were studied. In the group there
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA601290) and the National Natural ScienceFoundation of China (No. 20247012 50578155)
文摘Effects of Al(Ⅲ) concentration and pH on the speciation of Al(Ⅲ) in polyaluminum chloride (PACl) solutions especially on the Al13 fraction were investigated. A series of PACl samples were prepared over the range of Al(Ⅲ) concentration from 0.01 to 2.0 mol/L with the B (OH/Al ratio) value from 1.0 to 2.5 by forced hydrolysis of AICl3. The samples were characterized by ferron assay, pH and 27^Al NMR. It was shown that the Al(Ⅲ) concentration had a dramatic effect on the hydrolysis processes and the species distribution of PACl was in relate to the decrease of pH. The fraction of Al species, Alb (or Al13) decreased and Al0 increased with increase of total Al(Ⅲ) concentration. Under the condition of Al(Ⅲ) 2.0 reel/L, B = 2.5, the pH value was 2.73 and no Al13 could be detected. During diluting and aging, the species distribution evoIved. The Al13 could then be detected again and the amounts increased with time. If the diluted samples were concentrated by freeze dry at -35℃ or heating at 80℃, the pH value and Al13 content would decrease with the increased concentration. It demonstrated that the key factor for formation of Al13 in concentrated PACl was pH value.
基金This study was supported by the Natural Science Foundation of Guangdong Province, China (No.101595 and No. 32830).
文摘Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions.
基金Chinese Joint Seismological Science Foundation (100110).
文摘The influence of non-uniqueness in selecting statistical time ranges on seismicity parameters of b value and annual mean occurrence rate ν4 is widely analyzed and studied. The studied result states that the influence of statistical time range on the b value is generally smaller than on the annual mean rate. Owing to the exponentially functional relation between the annual mean rate and b value, the variation of b value by varying statistical time range brings about decrease or increase in the annual mean rates of each magnitude interval with power progression law. These results will exert a synthetic effect on seismic safety evaluation results in various regions in our country.
文摘Objective To analyze the serum keratin 18(K18)level of patients with hepatitis B virus(HBV)-related acute-on-chronic liver failure(HBV-ACLF)and its correlation with prognosis.Methods From December 2012 to October 2014,120 patients who visited Fuzhou Infectious Diseases Hospital and were diagnosed with HBV-ACLF were enrolled,and 20 chronic hepatitis B(CHB)pa-
基金the University of Mosul,College of Education for Pure Science,Department of PhysicsUniversity of Kerbala,College of Science,Department of Physics for supporting this work
文摘The properties of the ground and excited-state(γ-and β-bands) of ^168-178 Hf nuclei have been studied.The ratio r(I +2/I) and Eγ(I→I-2)/I have been calculated as a function of the spin(I) to determine the groundstate evolution. The results indicate that these isotopes have a rotational property SU(3). The energy levels for the ground-state, γ-and β-bands of ^168-178 Hf have been calculated using the Interacting Boson Model and Semi Empirical Formula(SEF). The parameters of the best fit to the measured data are determined. The behavior of energy and B(E2) ratios in the ground state band are examined.
基金the invaluable support of the College of Science at the University of Kerbala is warmly acknowledged
文摘The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model(IBM-1). Predictions are given for the excited state energies for the ground state, β and γ-bands, the transition probabilities between these states, the rotational moment of inertia, and the energy staggering in the γ-band energies. The results of these calculations are compared with the experimental data on these isotopes.
文摘The Generalized Collective Model (GCM) is applied to the even even neutron rich 104,106,108 Mo isotopes. With GCM the energy spectra, absolute B(E2) values, some B(E2) branching ratios and Potential Energy Surfaces (PES) for the 104,106,108 Mo isotopes are calculated. The PES of all these isotopes show a prolate minimum which becomes more pronounced in 106 Mo. The results are in agreement with the recent experimental report but are different from the viewpoint of the triaxial rotors, or γ soft deformation. Through a systematic study of PES, it is suggested that the even even neutron rich 104,106,108 Mo isotopes have prolate deformation.