Evaluation of 3D Printed Gelatin‐Based Scaffolds with Varying Pore Size for MSC‐Based Adipose Tissue Engineering

Adipose tissue engineering aims to provide solutions to patients who require tissue reconstruction following mastectomies or other soft tissue trauma. Mesenchymal stromal cells (MSCs) robustly differentiate into the adipogenic lineage and are attractive candidates for adipose tissue engineering. This work investigates whether pore size modulates adipogenic differentiation of MSCs toward identifying optimal scaffold pore size and whether pore size modulates spatial infiltration of adipogenically differentiated cells. To assess this, extrusion‐based 3D printing is used to fabricate photo‐crosslinkable gelatin‐based scaffolds with pore sizes in the range of 200–600 µm. The adipogenic differentiation of MSCs seeded onto these scaffolds is evaluated and robust lipid droplet formation is observed across all scaffold groups as early as after day 6 of culture. Expression of adipogenic genes on scaffolds increases significantly over time, compared to TCP controls. Furthermore, it is found that the spatial distribution of cells is dependent on the scaffold pore size, with larger pores leading to a more uniform spatial distribution of adipogenically differentiated cells. Overall, these data provide first insights into the role of scaffold pore size on MSC‐based adipogenic differentiation and contribute toward the rational design of biomaterials for adipose tissue engineering in 3D volumetric spaces.     

基于实测光谱的植被指数对水稻叶面积指数的响应特征分析

叶面积指数(LAI)是目前最常用的农业生态监测指标,可以为农作物的病虫害监测、作物长势监测、碳循环、生物量估算及作物估产提供依据。植被指数(VI)是卫星LAI产品生产的重要数据源,但不同VIs对植被LAI的响应特征具有一定的差异性。以江西省水稻为例,基于实测光谱提取了水稻实测VIs,结合实测LAI,讨论了归一化植被指数(NDVI)、增强型植被指数(EVI)、土壤调节植被指数(SAVI)和修正的土壤调节植被指数(MSAVI)四种常见VIs对LAI的响应特征,并与MODIS LAI备用算法的计算结果进行了对比分析,研究了不同VIs用于LAI产品反演的可行性及存在的问题。通过对不同实测VIs-LAI模型精度的评估,分析其应用于LAI反演的适应性,结果显示EVI,SAVI和MSAVI比NDVI有更好的适应性,其中EVI效果最优。此外,通过对比MODIS LAI备用算法查找表,发现针对MODIS LAI备用算法中草地与谷物作物这一地表覆盖大类,在LAI>4时,NDVI出现饱和;而实测水稻作物的NDVI在LAI>2时开始出现饱和;且当NDVI相同时,查找表LAI远大于实测LAI,MODIS备用算法中使用的地表覆盖产品分类过粗可能是造成这一结果的主要原因。因此MODIS LAI备用算法在该区域水稻LAI监测中可能产生较大误差,有必要改用其他VIs优化该备用算法。通过对比分析四种VIs模型对LAI的预测误差,发现EVI,SAVI和MSAVI精度明显优于NDVI,基于EVI的模型平均预测误差仅为MODIS LAI备用算法的1/6,基于实测NDVI反演算法的1/2,因此设计基于EVI的LAI算法对LAI的反演精度有一定的提升空间。     

农作物冠层光谱信息检测技术及方法综述

相比传统的化学方法及主观视觉测定植物生理信息指标,通过光谱辐射仪对农作物冠层信息的评估更简单、快速和精确。本文结合近年来农作物群体信息的获取方法,综述了不同类型光谱仪尤其以国际上应用最广泛的Cropscan多光谱辐射仪在农作物群体叶面积指数、生物量、氮素及叶绿素的预测,病虫害的监测及产量预测中的应用。总结了不同类型的的植被指数(VIs)、冠层光谱的获取及光谱分析方法,比较了不同农作物建立相关模型的回归系数。总体上建立的数学模型的相关系数较高,能实现对农作物各种生理信息等的检测。此外,将多光谱辐射仪与多种传感器相结合所得到的综合信息对于全面评价农作物生长情况具有重要指导价值。     

Calculus of sequential normal compactness in variational analysis

In this paper we study some properties of sets, set-valued mappings, and extended-real-valued functions unified under the name of “sequential normal compactness.” These properties automatically hold in finite-dimensional spaces, while they play a major role in infinite-dimensional variational analysis. In particular, they are essential for calculus rules involving generalized differential constructions, for stability and metric regularity results and their broad applications, for necessary optimality conditions in constrained optimization and optimal control, etc. This paper contains principal results ensuring the preservation of sequential normal compactness properties under various operations over sets, set-valued mappings, and functions.     

A differential oligopoly game with differentiated goods and sticky prices

We investigate a dynamic oligopoly game where goods are differentiated and prices are sticky. We study the open-loop and the closed-loop memoryless Nash equilibrium, and show that the latter equilibrium entails a larger level of steady state production as compared to the former; both equilibria entail a larger level of production in steady state than the static game. We also study the effects of price stickiness and product differentiation upon the steady state equilibrium allocation and profits. The per-firm equilibrium output is increasing in both product differentiation and price stickiness, while profits are increasing in both product differentiation and the speed of price adjustment. The steady state social welfare monotonically increases in the speed of price adjustment, and the overproduction entailed by dynamic competition has beneficial effect from a social standpoint.     

A global rigidity theorem for weakly Landsberg manifolds

In this paper we study a global rigidity property for weakly Landsberg manifolds and prove that a closed weakly Landsberg manifold with the negative flag curvature must be Riemannian.     

Positioning of new brands in an experiment

This paper deals with an experimental investigation of positioning new brands. For this purpose, a management game was carried out with students. The brands introduced in the cause of the game were analysed in respect to their positions in a two-dimensional feature space. We try to find out which of the two strategies, niche policy and imitation, is more frequently used in complex decision situations and if there is a difference in profits. Furthermore, we want to find out, whether differences of prices and advertising exist in our experiment depending on the positioning strategy used.     

多体系统动力学设计灵敏度分析直接微分法

针对受完整约束的多体系统动力学微分／代数方程数学模型动态最优化设计问题，建立了通用的目标函数和约束方程，并以此为基础，用直接微分方法系统地推导出了计算设计灵敏度的通用公式，最后通过平面机械臂模型对理论结果和相应算法进行了验证．     

Assessing and predicting changes in vegetation cover associated with military land use activities using field monitoring data at Fort Hood, Texas

We assessed short-term impacts of changes in military training load on vegetative cover at Fort Hood, TX. From 1989 to 1995, permanent field transects were monitored for vegetative cover and land use disturbance using standard army monitoring methods [Land Condition Trend Analysis (LCTA)]. Land use intensity (training load) was quantified and used to develop a model to predict future vegetation cover values. We found that standard Army monitoring methods detected changes in installation resources associated with changes in training load. Increased training loads were associated with increased measures of disturbance, decreased ground cover, and decreased aerial vegetative cover. We found that the spatial pattern of disturbance and vegetation cover remained relatively constant over the study period despite large variations in overall training load. Our model used the consistency in spatial cover patterns over time and the strong relationship between training load and vegetation cover to predict the impact of future training loads on vegetation.