The cyclotide fingerprint in oldenlandia affinis: elucidation of chemically modified, linear and novel macrocyclic peptides

The complete suite of cyclotides present in Oldenlandia affinis (Rubiaceae), the plant that was originally found to contain this unique family of circular proteins, has been characterised. This study expands the number of known cyclotides in this plant to 17, of which nine new sequences (kalata B9-B17) were characterised in this work. In addition, five derivatives that contain oxidation products of the conserved tryptophan were identified, and it was shown that the formation of these derivatives is catalysed by exposure to sunlight. Furthermore, we describe two "linear" cyclotide analogues. These acyclic peptides have three intact disulfide bonds, and their N and C termini coincide with the hypothesised cleavage sites from the precursor protein. This work increases our knowledge about the sequence variation that is accommodated by the cyclic cystine knot scaffold, confirms its applicability as a template for drug design, and also shows the first natural degradation pathways for cyclotides. These pathways have important implications for the persistence and environmental fate of the cyclotides if used as crop-protection agents.     

Large-scale fabrication of bioinspired fibers for directional water collection

Spider-silk inspired functional fibers with periodic spindle-knots and the ability to collect water in a directional manner are fabricated on a large scale using a fluid coating method. The fabrication process is investigated in detail, considering factors like the fiber-drawing velocity, solution viscosity, and surface tension. These bioinspired fibers are inexpensive and durable, which makes it possible to collect water from fog in a similar manner to a spider's web.     

基于广义逆矩阵的B样条曲线节点消去算法研究

为了能运用广义逆矩阵理论来研究B样条曲线的节点消去问题，以解决在B样条曲线曲面拟合过程中产生的冗余节点数据，提出了一种基于广义逆矩阵的B样条曲线节点消去算法，该算法首先利用广义逆矩阵在处理奇异性问题上的独特作用来获得B样条曲线的节点可以消去的充要条件；然后在此基础上，又提出了消去多个节点的算法，算法对每个可以消去的节点都可计算相应的广义逆矩阵，而且仅进行一次矩阵的相乘即可得到由消去这个节点而产生的新的控制顶点和节点。实验表明，该算法的精度优于或近似于现有的Tiller算法，而时间效率则同于或近似于Tiller的算法。由于通过调整算法中的误差阈值，可以有效地控制消去节点后的曲线与原来曲线的误差，因此算法可以用于工程实践。     

华龙国际大厦混合结构构件及节点设计

论述了矩形钢管混凝土柱钢框架、混凝土核心筒结构在江西华龙国际大厦的应用，介绍了矩形钢管混凝土混合结构总体设计、节点大样及构造。     

满足数据点切向约束的二次B样条插值曲线

给出一种二次B样条曲线插值方法.利用数据点的参数化和节点向量的自由度,构造在各数据点满足切向约束的二次B样条插值曲线,直观地控制插值曲线达到预期形状.用文中方法构造插值曲线是一个递推过程,不必预先确定数据点参数值和节点向量、不必解线性方程组,而是在插值过程中根据数据点及其切向的约束条件递推地确定数据点的参数值、节点和控制顶点.该文方法允许插值曲线各段的连接点与数据点不一致,以使得二次B样条插值曲线的形状更自然.而且在满足数据点切向约束的条件下,还可利用节点进一步调控插值曲线的形状.另外,用文中方法构造的二次B样条插值曲线对于数据点的改变具有较好的局部性质.文中最后给出一些例子将该文方法与其它一些插值方法进行比较,实验结果表明,该文方法是有效的.     

数据去冗余的多尺度多结点技术

从多结点样条理论出发，提出一种自适应的多层次淘汰冗余数据的算法，并通过不同的采样数据对算法进行了有效的论证．充分利用多结点样条函数拟合的基数型、显式计算和局部性等优点．该算法可用于采样数据的压缩或针对现有算法的数据预处理．     

基于边界节点法的MATLAB 工具箱开发

0引言 Helmholtz方程作为简化的波动方程,长期以来备受关注.求解Helmholtz方程的数值方法主要有有限差分法、有限元法和边界元法等.这些方法主要基于网格近似或者需要背景网格积分,在处理高波数或高频率Helmholtz方程及高维问题时存在网格划分困难和内存消耗大等缺点.基于点的近似思想,无网格方法在一定程度上减少对网格的依赖,甚至不需要网格。     

应用NURBS曲面磨光多面体

本文应用ＮＵＲＢＳ曲面磨光多面体,产生了处处Ｃ′连续的过渡曲面．多面体的磨光分为边的磨光和顶点的磨光两种情形,边的磨光相对较容易,而顶点的磨光则很困难．本文所采用的应用ＮＵＲＢＳ曲面磨光多面体的顶点和边的方法,不仅可以统一实现二者的磨光操作,而且方法简单且统一,产生了Ｃ′连续的过渡面．较之以前的方法,首先,利用ＮＵＲＢＳ曲面可以精确地描述对边磨光所用的柱面（等半径或非等半径）,其次,在对顶点的磨光中,同以往的方法不同,将与该顶点相邻的边的过渡曲面相互分离,并首次引入了“补面”的概念,使得对该点所产生的过渡曲面处处Ｃ′连续．本算法首先构造用以磨光多面体顶点和边的ＮＵＲＢＳ曲面的边界曲线网络图产生边界曲线的控制点及其权值（ＮＵＲＢＳ表示）,然后依据连续性准则,产生ＮＵＲＢＳ曲面的控制信息．     

纽结带形建筑表皮的拓扑学分析

引进拓扑学的纽结理论来指导分析纽结带形表皮的设计,首先从分析纽结带形表皮的拓扑学特征入手,提出了纽结类带形表皮和链环类带形表皮设计的造型规律,同时利用琼斯多项式来阐述纽结带形表皮的拓扑同痕不变量,并分别对纽结带形表皮的复杂度,以及纽结带形表皮间的环绕、串联和拼合进行阐述,力求利用拓扑学中纽结理论解决一些建筑纽结带形表皮的设计中所遇到的问题。     

Almost strictly total positivity of NUAT B-spline basis

Total positivity of spline basis has been well known in the theory of computer aided geometry design, which is highly related with good shape preserving property. Almost strictly total positivity is stronger, which could determine the positive minors while the other is zero. In this paper, a geometrical approach is proposed to prove the collection matrices of NUAT B-spline basis are almost strictly totally positive. In this paper, knot insertion algorithm combined with coefficient variation of NUAT B-spline function, we put forward an intuitive and geometrical method.