In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for e...In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.展开更多
The asymptotic solution to the scattering problem on a set of small particles, supplemented into homogeneous material, is used for modeling the materials with the desired refractive index. The consideration concerns t...The asymptotic solution to the scattering problem on a set of small particles, supplemented into homogeneous material, is used for modeling the materials with the desired refractive index. The consideration concerns the case of acoustic scalar scattering and the solution to initial scattering problem is built using an asymptotic approach. The closed form solution is reduced for the scattering problem. This is significant advantage of approach because there is no need to solve the respective system of boundary integral equations. High accuracy of solving the scattering problem is achieved by choosing the optimal parameters of the domain with small particles. The approach allows obtaining an explicit formula for the refractive index of the resulting inhomogeneous material. The numerical calculations show the possibility to get the specific values of refractive index including its negative values.展开更多
Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort(CPUE) of set-net is affected by spatial-temporal and environmental factors but no research h...Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort(CPUE) of set-net is affected by spatial-temporal and environmental factors but no research has been conducted on this subject. In this study, we used generalized additive models(GAMs) to explore the influence of spatial-temporal and environmental factors on CPUEs of species aggregated, small yellow croaker(Larimichthys polyactis), and octopus(Octopus variabilis) based on logbooks investigations conducted at 4 stations in an alongshore area of Haizhou Bay from 2011 to 2012. The results showed that all CPUEs exhibited significant spatial-temporal differences at various scales. Aggregated CPUE was high when the sea surface temperature(SST) was 15-18℃ and 20-23℃, which was mainly determined by life history traits of the octopus and small yellow croaker(optimal SSTs 14-17℃ and 19-24℃, respectively). Chlorophyll-a concentration had significant influences on the aggregated, small yellow croaker and octopus CPUEs at optimal ranges of 3.8-6.2 mg m^(-3), 4.2-4.8 mg m^(-3) and 4.5-5.5 mg m^(-3), respectively. Flow through the net had positive relationships with CPUEs. The approximate logarithmic trends in regression curves had a critical point of 2.5 Mm^3 d^(-1), which was the dividing point that differentiated whether the major factor affecting CPUEs was the flow velocity or the fishery resource. Our results from this study will help guide fishery production and improve catch rate of set-net fishing in Haizhou Bay.展开更多
贝叶斯网络(bayesian network,BN)小数据集条件下,定性最大后验概率(qualitative maximum a posteriori,QMAP)估计往往会违反给定的专家约束,这就导致QMAP估计偏离真实值。为了克服该算法的缺陷,提出了一种改进的QMAP算法。首先,学习出Q...贝叶斯网络(bayesian network,BN)小数据集条件下,定性最大后验概率(qualitative maximum a posteriori,QMAP)估计往往会违反给定的专家约束,这就导致QMAP估计偏离真实值。为了克服该算法的缺陷,提出了一种改进的QMAP算法。首先,学习出QMAP估计,再结合保序回归方法对违反不等式约束的参数进行校正;然后使用一种微调策略对校正后的参数做进一步调整,使所得参数能够满足专家约束;最后,与最大似然估计(maximum likelihood estimation,MLE)和QMAP算法对比。仿真实验结果表明:在小数据集条件下,提出的算法满足所有约束条件,KL(Kullback-Leibler)散度始终低于其他2种算法,运行时间高于其他2种算法约0.1 s,影响甚微,且推理结果贴近真实值,偏差维持在±0.05之间。改进的QMAP算法的综合性能优于MLE、QMAP算法,并具有较好的实用性。展开更多
Background: Pemetrexed (PEM) is an efficacious multi-targeted antifolate with acceptable toxicities for non-squamous non-small cell lung cancer (non-Sq NSCLC). However, in the clinical setting, PEM has more severe adv...Background: Pemetrexed (PEM) is an efficacious multi-targeted antifolate with acceptable toxicities for non-squamous non-small cell lung cancer (non-Sq NSCLC). However, in the clinical setting, PEM has more severe adverse effects than those reported. The aim of this study was to identify the factors for the toxicities of PEM-containing chemotherapy in non-Sq NSCLC patients in the clinical setting. Patients and Methods: We retrospectively evaluated the factors related to PEM toxicities in chemotherapy-naive patients with non-Sq NSCLC from September 2009 to July 2013 at our hospital. Logistic regression model was used in the univariate and multivariate analyses. Results: In total, 104 patients were analyzed. Grades 3 to 5 hematologic toxicities were frequent and included neutropenia (42%), febrile neutropenia (7%), anemia (18%), thrombocytopenia (17%), and disseminated intravascular coagulation (2%). On multivariate analyses, the predictors were poor performance status (PS) [odds ratio (OR): 4.89, 95% confidence interval (CI): 1.22 - 19.4] and low body mass index (OR: 1.44, 95% CI: 1.05 - 1.98) for febrile neutropenia;concomitant chronic infectious disease (OR: 6.63, 95% CI: 1.59 - 27.5) and bevacizumab use (OR: 3.57, 95% CI: 1.36 - 9.32) for neutropenia;poor PS (OR: 3.02, 95% CI: 1.33 - 6.85) for thrombocytopenia;and low serum albumin level (OR: 0.22, 95% CI: 0.08 - 0.63) for non-hematologic toxicities. Conclusions: In addition to the previously reported predictors of PEM toxicities, the presence of concomitant chronic infectious disease was associated with hematologic toxicities. Patient groups who are not sufficiently evaluated in clinical trials should be carefully monitored for the development of more toxicities than expected.展开更多
文摘In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.
文摘The asymptotic solution to the scattering problem on a set of small particles, supplemented into homogeneous material, is used for modeling the materials with the desired refractive index. The consideration concerns the case of acoustic scalar scattering and the solution to initial scattering problem is built using an asymptotic approach. The closed form solution is reduced for the scattering problem. This is significant advantage of approach because there is no need to solve the respective system of boundary integral equations. High accuracy of solving the scattering problem is achieved by choosing the optimal parameters of the domain with small particles. The approach allows obtaining an explicit formula for the refractive index of the resulting inhomogeneous material. The numerical calculations show the possibility to get the specific values of refractive index including its negative values.
基金funded through the Special Fund for Agro-Scientific Research in the Public Interestthe Special Public Welfare Industry (agriculture) Research-Research and Demonstration of Fisheries Fishing Technology and Fishing Gear (No. 201203018)the National Natural Science Foundation of China (No. 31402350)
文摘Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort(CPUE) of set-net is affected by spatial-temporal and environmental factors but no research has been conducted on this subject. In this study, we used generalized additive models(GAMs) to explore the influence of spatial-temporal and environmental factors on CPUEs of species aggregated, small yellow croaker(Larimichthys polyactis), and octopus(Octopus variabilis) based on logbooks investigations conducted at 4 stations in an alongshore area of Haizhou Bay from 2011 to 2012. The results showed that all CPUEs exhibited significant spatial-temporal differences at various scales. Aggregated CPUE was high when the sea surface temperature(SST) was 15-18℃ and 20-23℃, which was mainly determined by life history traits of the octopus and small yellow croaker(optimal SSTs 14-17℃ and 19-24℃, respectively). Chlorophyll-a concentration had significant influences on the aggregated, small yellow croaker and octopus CPUEs at optimal ranges of 3.8-6.2 mg m^(-3), 4.2-4.8 mg m^(-3) and 4.5-5.5 mg m^(-3), respectively. Flow through the net had positive relationships with CPUEs. The approximate logarithmic trends in regression curves had a critical point of 2.5 Mm^3 d^(-1), which was the dividing point that differentiated whether the major factor affecting CPUEs was the flow velocity or the fishery resource. Our results from this study will help guide fishery production and improve catch rate of set-net fishing in Haizhou Bay.
文摘贝叶斯网络(bayesian network,BN)小数据集条件下,定性最大后验概率(qualitative maximum a posteriori,QMAP)估计往往会违反给定的专家约束,这就导致QMAP估计偏离真实值。为了克服该算法的缺陷,提出了一种改进的QMAP算法。首先,学习出QMAP估计,再结合保序回归方法对违反不等式约束的参数进行校正;然后使用一种微调策略对校正后的参数做进一步调整,使所得参数能够满足专家约束;最后,与最大似然估计(maximum likelihood estimation,MLE)和QMAP算法对比。仿真实验结果表明:在小数据集条件下,提出的算法满足所有约束条件,KL(Kullback-Leibler)散度始终低于其他2种算法,运行时间高于其他2种算法约0.1 s,影响甚微,且推理结果贴近真实值,偏差维持在±0.05之间。改进的QMAP算法的综合性能优于MLE、QMAP算法,并具有较好的实用性。
文摘Background: Pemetrexed (PEM) is an efficacious multi-targeted antifolate with acceptable toxicities for non-squamous non-small cell lung cancer (non-Sq NSCLC). However, in the clinical setting, PEM has more severe adverse effects than those reported. The aim of this study was to identify the factors for the toxicities of PEM-containing chemotherapy in non-Sq NSCLC patients in the clinical setting. Patients and Methods: We retrospectively evaluated the factors related to PEM toxicities in chemotherapy-naive patients with non-Sq NSCLC from September 2009 to July 2013 at our hospital. Logistic regression model was used in the univariate and multivariate analyses. Results: In total, 104 patients were analyzed. Grades 3 to 5 hematologic toxicities were frequent and included neutropenia (42%), febrile neutropenia (7%), anemia (18%), thrombocytopenia (17%), and disseminated intravascular coagulation (2%). On multivariate analyses, the predictors were poor performance status (PS) [odds ratio (OR): 4.89, 95% confidence interval (CI): 1.22 - 19.4] and low body mass index (OR: 1.44, 95% CI: 1.05 - 1.98) for febrile neutropenia;concomitant chronic infectious disease (OR: 6.63, 95% CI: 1.59 - 27.5) and bevacizumab use (OR: 3.57, 95% CI: 1.36 - 9.32) for neutropenia;poor PS (OR: 3.02, 95% CI: 1.33 - 6.85) for thrombocytopenia;and low serum albumin level (OR: 0.22, 95% CI: 0.08 - 0.63) for non-hematologic toxicities. Conclusions: In addition to the previously reported predictors of PEM toxicities, the presence of concomitant chronic infectious disease was associated with hematologic toxicities. Patient groups who are not sufficiently evaluated in clinical trials should be carefully monitored for the development of more toxicities than expected.
