基于多尺度特征和注意力机制的肝脏组织病理图像语义分割网络

针对肝脏组织病理图像分割中存在的正常组织和异常组织过渡区域较难分割和空洞较多的问题,设计基于多尺度特征和注意力机制的肝脏组织病理图像语义分割网络.在编码器中提取融合多尺度特征,改善正常组织和异常组织过渡区域的分割效果.同时利用注意力机制对空间维度和通道维度进行相关性建模,获得每个像素类内响应和通道间的依赖关系,缓解肝脏组织病理图像空洞较多对网络学习带来的影响.实验表明文中网络可较快速准确分割肝脏组织病理图像损伤区域.     

Interactive Multiresolution Editing of Arbitrary Meshes

This paper presents a novel approach to multiresolution editing of a triangular mesh. The basic idea is to embed an editing area of a mesh onto a 2D rectangle and interpolate the user-specified editing information over the 2D rectangle. The result of the interpolation is mapped back to the editing area and then used to update the mesh. We adopt harmonic maps for the embedding and multilevel B-splines for the interpolation. The proposed mesh editing technique can handle an arbitrary mesh without any preprocessing such as remeshing. It runs fast enough to support interactive editing and produces intuitive editing results.     

产物释放促进剂对固定化紫草细胞生产紫草色素的影响

研究了多种产物释放促进剂对海藻胶包埋的紫草细胞生产紫草色素的效果。结果表明,在色素生产培养基中加入合适的产物释放促进剂可显著地刺激紫草色素的分泌及合成,并且该种处理方式的作用效果明显优于细胞透性预处理方式的效果。将固定化紫草细胞培养在质量分数为０．０８％、０．２４％Ｔｗｅｅｎ８０和０．２％Ｔｗｅｅｎ２０培养基中,培养１２ｄ紫草色素产量分别为每克干细胞含４２．２０、６２．５２和３８．７３ｍｇ,比对照分别提高２．８２、４．６６和２．５１倍。在质量分数为０．２％Ｔｗｅｅｎ２０培养基中培养３５ｄ时,细胞合成色素总产量达每克干细胞含１８１．５ｍｇ,比对照提高４．２倍。     

Electrospinning of polymer melts: Phenomenological observations

Melt electrospinning is an alternative to solution electrospinning, however, melt electrospinning has typically resulted in fibers with diameters of tens of microns. In this paper we demonstrate that polypropylene fibers can be reduced from 35 ± 8 μm in diameter, to 840 ± 190 nm with a viscosity-reducing additive. Melt electrospun blends of poly(ethylene glycol)-block-poly(?-caprolactone) (PEG₄₇-b-PCL₉₅) and poly(?-caprolactone) (PCL) produced fibers with micron-scale diameters (2.0 ± 0.3 μm); this was lowered to 270 ± 100 nm by using the gap method of alignment for collection. The collected melt electrospun fibers often fused together where they touched, allowing the stabilization of relatively thick non-woven felts. The melt electrospun collection also included coiled circles and looped patterns of fibers approximately 150-250 μm in diameter. The polymer jet was visible between the collector and spinneret for particularly significant lengths, and underwent coiling and buckling instabilities close to the collector. The focused deposition of melt electrospun fibers was maintained when multiple jets were observed, with the collections from multiple jets separated by 3.8 ± 0.5 mm for a 5 cm collector gap. The frequent fusion points between melt electrospun fibers, and a reduction in diameter for the gap method of alignment, indicated that the melt electrospun fibers are still slightly molten at collection.     

Application of Ultrasound and Ultrasound-Assisted Osmotic Dehydration in Drying of Fruits

This work examines the influence of ultrasonic and ultrasonic assisted osmotic dehydration pretreatments on the dehydration of eight fruits (banana, genipap, jambo, melon, papaya, pineapple, pinha, and sapota). An overview of the effects of ultrasound application on water loss, sugar gain, and effective diffusivity of water during the dehydration process is presented. The results showed significant differences for water loss and sugar gain among the fruits that were studied, which were analyzed based on the changes observed on the tissue structure of the fruit. The results also showed that the effective diffusivity of water in the fruit increased after application of ultrasound reducing air-drying time.     

拟黑多刺蚁提取物对小鼠缓解体力疲劳作用的研究

为研究拟黑多刺蚁对缓解体力疲劳的作用 ,将 6 0只昆明种小鼠分为 4组 ,3个拟黑多刺蚁水提取物阳性试验组 (1 0 74、0 35 8、0 0 36g kgBW)和 1个阴性对照组 ,每日分别给昆明种小鼠称体重后经口灌胃 ,连续 30d后做负重游泳实验和三项生化指标 (血清尿素、肝糖原、血乳酸 )测试。实验结果表明 ,低剂量组小鼠负重游泳试验时间显著延长 (P <0 0 5 ) ;高剂量组小鼠运动后的血清尿素水平降低 ;3个试验组与对照组的小鼠肝糖原储备量相比均有非常显著的增加 (P <0 0 1) ;小鼠运动后血乳酸值差异无显著性 (P >0 .0 5 )。本试验结果提示拟黑多刺蚁水提取物具有缓解体力疲劳作用。     

基于快速原型的组织工程支架成形技术

组织工程是生物制造的重要发展阶段,通过先成形生物材料的支架,然后在上面复合细胞的方式,来实现组织器官的人工制造。支架的性能在组织工程的应用中非常重要。相比传统的支架成形方法,基于离散—堆积原理的快速原型技术,所制造的支架个性化程度较高:支架的孔隙率、力学性能、生物相容性和降解特性等方面,可以通过参数设计和材料选择的方法进行人工设定;因此非常适于构建结构性的组织和器官。介绍了现有的基于快速原型的组织工程支架的成形技术,总结了其特点及应用现状,并分析讨论了其优缺点。     

高黏度低后酸酸奶发酵剂的筛选

对分离到的12株优良乳酸菌,进行了单发酵试验和复配发酵实验。在单发酵实验中分析嗜热链球菌的产粘特性和保加利亚乳杆菌的产酸特性,在复配发酵实验中测定在贮藏期内(21 d)酸度、pH值、黏度、脱水收缩性及对其进行感官鉴评。结果表明,组合PZST4-PZLB5在储存期间保持了良好的风味和流变学特性,并且后酸化程度较小、产黏高,因而适合作为优良的酸奶发酵剂。     

The effect of citric acid and pH on growth and metabolism of anaerobic Saccharomyces cerevisiae and Zygosaccharomyces bailii cultures

The effects of citric acid at pH values of 3.0, 4.0, and 4.5 on growth and metabolism of anaerobic Saccharomyces cerevisiae and Zygosaccharomyces bailii cultures were investigated. S. cerevisiae and Z. bailii exhibited similar tolerances to citric acid, as determined by growth measurements, at all three pH values investigated. The citric-acid-induced growth inhibition of both yeast species increased with increasing pH values, indicating that the antimicrobial mechanism of citric acid differs from that of classical weak-acid preservatives. In S. cerevisiae, citric acid shifted the primary energy metabolism towards lower ethanol production and higher glycerol production, thus resulting in lower ATP production. These metabolic changes in S. cerevisiae were pH-dependent; i.e. the higher the pH, the lower the ATP production, and they may explain why growth of S. cerevisiae is more inhibited by citric acid at higher pH values. In Z. bailii, citric acid also caused an increased glycerol production, although to a lesser extent than in S. cerevisiae, but it caused virtually no changes in ethanol and ATP production.     

Production and Potential of Bioactive Glass Nanofibers as a Next‐Generation Biomaterial

Over the past decades, bioactive glass has played a central role in the bone regeneration field, due to its excellent bioactivity, osteoconductivity, and even osteoinductivity. Herein, exploitation of bioactive glass as a one‐dimensional nanoscale fiber by employing an electrospinning process based on a sol–gel precursor is reported for the first time. Under controlled processing conditions, continuous nanofibers have been generated successfully with variable diameters. The excellent bioactivity of the nanofiber is confirmed in vitro within a simulated body fluid by the rapid induction of bonelike minerals onto the nanofiber surface. The bone‐marrow‐derived cells are observed to attach and proliferate actively on the nanofiber mesh, and differentiate into osteoblastic cells with excellent osteogenic potential. The bioactive nanofibers have been further exploited in various forms, such as bundled filament, nanofibrous membrane, 3D macroporous scaffold, and nanocomposite with biopolymer, suggesting their versatility and potential applications in bone‐tissue engineering. Based on this study, the bioactive nanofibrous matrix is regarded as a promising next‐generation biomaterial in the bone‐regeneration field.