Background The degree of pathological microvascular proliferation is an important element in evaluation of the astrocytoma grade. This study was aimed to quantitatively assess the microvascular permeability of brain a...Background The degree of pathological microvascular proliferation is an important element in evaluation of the astrocytoma grade. This study was aimed to quantitatively assess the microvascular permeability of brain astrocytoma with the volume transfer constant （Ktrans） and volume of extravascular extracellular space per unit volume of tissue （Ve） from dynamic contrast-enhanced magnetic resonance imaging （DCE-MRI） and to evaluate the effectiveness of the Ktr^n＇ and Ve in the grading of astrocytoma. Methods The highest values of the Kt~~s and Ve of 67 patients with astrocytoma （27 with grade II, 12 with grade III, and 28 with grade IV） were obtained. The comparisons of the differences of the Ktrans and Ve between the different grades were conducted using the Mann-Whitney rank-sum tests. Spearman＇s rank correlation coefficients were determined between Ktrans values, Ve values and astrocytoma grades. Receiver operating characteristic （ROC） curve analyses were performed to determine the cut-off values for the Ktrans and Ve to distinguish between the different grades of astrocytoma. Results There were significant differences （P〈0.001） between the different grades in the Ktrans values and Ve values, except for grades III and IV. The Ktrans values and Ve values were both correlated with astrocytoma grades （both P〈0.001）. The ROC curve analyses showed that the cut-off values for the Ktrans and Ve provided the best combination of sensitivity and specificity in distinguishing between grade II and grade III or IV astrocytomas. Conclusions DCE-MRI can play an important role in assessing the microvascular permeability and the grading of brain astrocytoma.展开更多
Machine vision has been recently utilized for quality control of food and agricultural products, which was traditionally done by manual inspection. The present study was an attempt for automatic defect detection and s...Machine vision has been recently utilized for quality control of food and agricultural products, which was traditionally done by manual inspection. The present study was an attempt for automatic defect detection and sorting of some single-color fruits such as banana and plum. Fruit images were captured using a color digital camera with capturing direction of zero degree and under illuminant D65. It was observed that growing decay and time-aging made surface color changes in bruised parts of the object. 3D RGB and HSV color vectors as well as a single channel like H （hue）, S （saturation）, V （value） and grey scale images were applied for color quantization of the object. Results showed that there was a distinct threshold in the histogram of the S channel of images which can be applied to separate the object from its background. Moreover, the color change via the defect and time-aging is correctly distinguishable in the hue channel image. The effect of illumination, gloss and shadow of 3D image processing is less noticeable for hue data in comparison to saturation and value. The value of H channel was quantized to five groups based on the difference between each pixel value and the H value of a healthy object. The percentage of different degree of defects can be computed and used for grading the fruits.展开更多
Along with the urban construction and industrial development, the original continuous riverway of the Muling River has been dammed into river sections of different lengths, which has seriously destroyed ecological env...Along with the urban construction and industrial development, the original continuous riverway of the Muling River has been dammed into river sections of different lengths, which has seriously destroyed ecological environment of the basin. In view of this, it is urgent to protect water ecological environment of the basin. This paper took the national ecological environment conservation instructions as the guidance, combined with the administrative division, planning and actual conditions of the basin, proposed principles and schemes for the grading of water spaces in the basin, as well as the hierarchic control requirements, to provide instructions for the conservation of the river basin.展开更多
文摘Background The degree of pathological microvascular proliferation is an important element in evaluation of the astrocytoma grade. This study was aimed to quantitatively assess the microvascular permeability of brain astrocytoma with the volume transfer constant （Ktrans） and volume of extravascular extracellular space per unit volume of tissue （Ve） from dynamic contrast-enhanced magnetic resonance imaging （DCE-MRI） and to evaluate the effectiveness of the Ktr^n＇ and Ve in the grading of astrocytoma. Methods The highest values of the Kt~~s and Ve of 67 patients with astrocytoma （27 with grade II, 12 with grade III, and 28 with grade IV） were obtained. The comparisons of the differences of the Ktrans and Ve between the different grades were conducted using the Mann-Whitney rank-sum tests. Spearman＇s rank correlation coefficients were determined between Ktrans values, Ve values and astrocytoma grades. Receiver operating characteristic （ROC） curve analyses were performed to determine the cut-off values for the Ktrans and Ve to distinguish between the different grades of astrocytoma. Results There were significant differences （P〈0.001） between the different grades in the Ktrans values and Ve values, except for grades III and IV. The Ktrans values and Ve values were both correlated with astrocytoma grades （both P〈0.001）. The ROC curve analyses showed that the cut-off values for the Ktrans and Ve provided the best combination of sensitivity and specificity in distinguishing between grade II and grade III or IV astrocytomas. Conclusions DCE-MRI can play an important role in assessing the microvascular permeability and the grading of brain astrocytoma.
文摘Machine vision has been recently utilized for quality control of food and agricultural products, which was traditionally done by manual inspection. The present study was an attempt for automatic defect detection and sorting of some single-color fruits such as banana and plum. Fruit images were captured using a color digital camera with capturing direction of zero degree and under illuminant D65. It was observed that growing decay and time-aging made surface color changes in bruised parts of the object. 3D RGB and HSV color vectors as well as a single channel like H （hue）, S （saturation）, V （value） and grey scale images were applied for color quantization of the object. Results showed that there was a distinct threshold in the histogram of the S channel of images which can be applied to separate the object from its background. Moreover, the color change via the defect and time-aging is correctly distinguishable in the hue channel image. The effect of illumination, gloss and shadow of 3D image processing is less noticeable for hue data in comparison to saturation and value. The value of H channel was quantized to five groups based on the difference between each pixel value and the H value of a healthy object. The percentage of different degree of defects can be computed and used for grading the fruits.
文摘Along with the urban construction and industrial development, the original continuous riverway of the Muling River has been dammed into river sections of different lengths, which has seriously destroyed ecological environment of the basin. In view of this, it is urgent to protect water ecological environment of the basin. This paper took the national ecological environment conservation instructions as the guidance, combined with the administrative division, planning and actual conditions of the basin, proposed principles and schemes for the grading of water spaces in the basin, as well as the hierarchic control requirements, to provide instructions for the conservation of the river basin.
