Successful medical management of a domestic longhair cat with subdural intracranial empyema and multifocal pneumonia          下载免费PDF全文

Thomas J.A. Cardy BSc  BVetMed  MVetMed  PhD  Richard Lam BVSc  MVetMed  DECVDI  Laureen M. Peters Dr med vet  Màrian Matas Riera DVM  DECVO  Steven De Decker DVM  PhD  MVetMed  DECVN 《Journal of Veterinary Emergency and Critical Care》2017,27(2):238-242

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Characteristics of dust particles abraded from pesticide treated seeds: 1. Size distribution using different measuring techniques          下载免费PDF全文

Dieter Foqué  Ingrid KA Zwertvaegher  Wouter Devarrewaere  Pieter Verboven  David Nuyttens 《Pest management science》2017,73(7):1310-1321

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基于CT扫描的煤矿排土场土壤孔隙三维多重分形特征   总被引：1，自引：0，他引：1  

张佳瑞  王金满  秦倩  白中科 《土壤通报》2017,(4):786-793

土壤孔隙对水分、养分的运移起着重要作用,重构土壤孔隙状况反映着复垦土壤质量的高低。本研究基于Math Works Matlab(2009a)平台,在对土壤孔隙CT扫描图片三维重建的基础上,运用多重分形理论对安太堡露天煤矿不同复垦年限排土场重构土壤(23年、20年、0年)以及原地貌土壤进行三维多重分形定量表征,以探讨重构土壤孔隙空间分布规律。结果表明:重构土壤孔隙三维结构具有多重分形特征,信息熵维D1、广义维数谱曲线弯曲程度△D、多重分形谱谱宽△α随着复垦年限逐渐增大,土壤孔隙状况得到改善,土壤孔隙分布越趋于复杂,变异程度较高;重构土壤及原地貌土壤孔隙三维分布多重分形谱函数△f0,呈左钩状,大概率孔隙占主要地位,孔隙分布不均匀。多重分形参数D1、D0-D1、△D、△α、△f间具有较好的相关性,从不同角度上反映了土壤孔隙三维分布的非均质性。  相似文献   

Computed tomographic contrast tenography of the digital flexor tendon sheath of the equine hindlimb          下载免费PDF全文

Rachel Agass  Jonathon Dixon  Barny Fraser 《Veterinary radiology & ultrasound》2018,59(3):279-288

Pre‐surgical investigation of digital flexor tendon sheath pathology remains challenging with current standard imaging techniques. The aim of this prospective, anatomical, pilot study was to describe the anatomy of the equine hind limb digital flexor tendon sheath using a combination of computed tomography (CT) and computed tomographic contrast tenography in clinically normal cadaver limbs. Ten pairs of hind limbs with no external abnormalities were examined from the level of the tarsometatarsal joint distally. Limbs initially underwent non‐contrast CT examination using 120 kVp, 300 mAs, and 1.5 mm slice thickness. Sixty millilitres of ioversol iodinated contrast media and saline (final concentration 100 mg/ml) were injected using a basilar sesamoidean approach. The computed tomographic contrast tenography examination was then repeated, before dissection of the specimens to compare gross and imaging findings. The combined CT and computed tomographic contrast tenography examinations provided excellent anatomical detail of intra‐thecal structures. The borders of the superficial and deep digital flexor tendons, and the manica flexoria were consistently identifiable in all limbs. Detailed anatomy including that of the mesotenons, two of which are previously undescribed, and the plantar annular ligament were also consistently identifiable. Dissection of all 10 pairs of limbs revealed there to be no pathology, in accordance with the imaging findings. In conclusion, the combination of CT and computed tomographic contrast tenography may be useful adjunctive diagnostic techniques to define digital flexor tendon sheath pathology prior to surgical exploration in horses.  相似文献   

免耕对稻油轮作系统土壤结构的影响   总被引：1，自引：1，他引：0  

刘玲玲  李超  房焕  赵杨  张中彬  彭新华  尹力初  周虎 《土壤学报》2021,58(2):412-420

为探明免耕对稻油轮作系统土壤结构的影响,基于湖南省洞庭湖区4a的耕作试验(2016—2019),采用X射线CT扫描技术和常规土壤物理分析方法,研究了旋耕和免耕对水稻土0～25 cm土层土壤结构的影响.与旋耕相比,免耕处理对0～5 cm土层的土壤容重和土壤有机碳无显著影响,但免耕处理显著提高了0～10 cm土层>2 mm...  相似文献   

深松结合秸秆还田对黑土孔隙结构的影响     

杨建君  盖浩  张梦璇  蔡育蓉  王力艳  王立刚 《中国农业科学》2023,56(5):892-906

【目的】东北黑土实施深松结合秸秆还田对土壤孔隙结构影响的研究缺乏明确性结论，为此开展本研究，旨在研究深松结合秸秆还田对黑土结构的影响机制，为合理耕层创建提供科学依据。【方法】利用在东北典型黑土区——黑龙江省绥化市青冈县开展的5年田间定位试验为平台，设置农民常规耕作（FP）、单独深松25 cm(T2)、深松25 cm结合秸秆还田（T3）和深松35 cm结合秸秆还田（T4）等处理，采用CT扫描技术开展土壤孔隙结构可视化和定量化研究，并结合田间持水量和容重等指标，探究深松结合秸秆还田对黑土孔隙结构的影响。【结果】通过土壤孔隙二维和三维图像可以清晰看出，各处理0—20 cm土层孔隙分布均明显少于20—40 cm土层，深松结合秸秆还田（T3、T4）的孔隙分布明显多于FP，增加了结构更为复杂的大孔隙。定量化分析表明，相较于FP，单独深松25 cm(T2)显著提高20—30 cm土层总孔隙度103.0%(P<0.05)，主要通过显著提高小孔隙（孔隙直径d≤0.50 mm）孔隙度91.3%和中孔隙（0.50 mm相似文献   

Comparison of X-ray CT and MRI of watercore disorder of different apple cultivars     

《Postharvest Biology and Technology》2014

Watercore is an internal disorder that appears as water-soaked, glassy regions near the core in apples. Fast and non-destructive solutions for sensing watercore would be readily accepted in the postharvest industry. X-ray CT and MRI were compared as potential imaging technologies for detecting this particular disorder. After matching the 3D datasets of X-ray CT and MRI, the images that were obtained on identical fruit were compared quantitatively. Both MRI and CT were able to detect watercore, however the contrast in MRI images was superior. High-resolution micro-CT images showed the microstructural changes in watercore fruit: the intercellular spaces of the affected apple tissue are filled with water. This explained the higher density that is detected here by the X-rays and the higher water content in the MRI. Mean and variance of the frequency distribution of MRI and X-ray CT intensity appeared to be a parameter that allows the identification of healthy apples from affected fruit. Automatic image processing based on thresholding the images resulted in comparable watercore classification accuracy of up to 89% for X-ray CT and 79% for MRI data, despite the better contrast in the MRI images.  相似文献   

基于CT扫描的不同粒形滤料孔隙结构特征          下载免费PDF全文

蔡九茂  宋蕾  张文正  翟国亮  许强  李鹏来 《农业工程学报》2022,38(19):94-101

滤层孔隙结构直接影响过滤过程中的颗粒沉积和运移效果。为了掌握砂石过滤器不同粒形滤料组成滤层的内部孔隙结构特征，该研究以粒径为1～1.18 mm的普通石英砂（QS1）、天然海砂（SS2）、改性玻璃（MG3）和玻璃微珠（GB4）4 种滤料为研究对象，采用CT 扫描技术对滤层孔隙模型进行了三维重构，利用VGStudio MAX、Image J等计算机图像处理软件，分析了 4 种滤层的孔隙率、孔径大小及孔隙形状参数，并结合分形理论确定了 4 种滤层孔隙结构的计盒分形维数。结果表明：4种滤层的表观孔隙率范围分别为0.397～0.446（QS1）、0.385～0.423（SS2）、0.407～0.456（MG3）、0.351～0.380（GB4），对应体积孔隙率分别为0.422、0.412、0.441、0.366；对应孔径范围分别为75～960、80～760、70～1 050、85～930 μm，圆度值区间分别为1.59～1.78、1.35～1.54、1.65～2.03、1.20～1.36，扁平度值区间分别为2.62～2.75、2.05～2.20、3.04～3.21、1.94～2.04，计盒维数均值分别为1.621、1.566、1.661、1.446。该研究定量表征了滤层孔隙结构特性，得出不同粒形滤料细观孔隙结构的差异：滤层表观孔隙率呈现"上高下低"分布规律，孔径分布规律表明滤层内均是小孔隙占多数，大孔隙占少数，且孔隙以狭长型为主。随着滤料棱角度增加，表观孔隙率分布越分散，体积孔隙率越大，大孔隙占比也相应增加，最大达到17.24%（MG3），孔隙形状更加偏离球形，表征孔隙结构复杂性的计盒维数相应增加，且分形维数与孔隙率呈负相关关系。滤层孔隙结构研究可为后续研究滤层内颗粒沉积和运移规律奠定基础。  相似文献   

Effects of different organic amendments on soil pore structure acquired by three-dimensional investigation     

Kefan Xuan  Xiaopeng Li  Xiuling Yu  Yifei Jiang  Jingchun Ji  Renhao Jia  Can Wang  Jianli Liu 《European Journal of Soil Science》2022,73(4):e13264

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Microstructural characterisation of commercial kiwifruit cultivars using X-ray micro computed tomography     

《Postharvest Biology and Technology》2014

The skin is the physical barrier between the fruit and the environment in which it develops. Environmental conditions during fruit development have a large influence on fruit quality, both at the time of harvest and during subsequent storage. It is hypothesised that some features of the skin and sub-epidermal tissues could provide information about the past growing conditions to which the fruit was exposed and therefore be of predictive value for storage quality. In this study, five commercial kiwifruit cultivars (‘Hayward’, ‘Hort16A’, ‘G3’, ‘G9’ and ‘G14’) were studied, and ‘Hayward’ fruit were manipulated during growth with different cultural practices. After harvest at horticultural maturity, X-ray micro computed tomography (μCT) was used to investigate features of the skin and the immediate parenchyma tissue. Despite orchard management practices (crop load and girdling) being observed to effect macro fruit quality parameters (mass, firmness, SSC, and DM), differences in microstructure (e.g. porosity) caused by these practices were not observed. However, porosity and pore size were found to be highly variable between cultivars. The thickness of dense sub-epidermal tissue could be readily measured and the 3-D distribution of raphide bundles was visible as high density particles distributed within the parenchyma. Overall, μCT was found to be a powerful technique to explore fruit epidermal and sub-epidermal structures in three dimensions at a micro level. However, the length of time required for data capture and analysis and the large number of samples required to overcome natural variation within horticultural products need to be considered. Future work may define the impact of differences in porosity or sub-epidermal anatomy on kiwifruit physiology (e.g. firmness change or sensitivity to low oxygen storage atmospheres). With this information, μCT could be used as a screening tool during plant breeding, or to determine the response to agronomic treatments, without conducting lengthy storage trials.  相似文献