Bioanalytical methods applied to endocrine disrupting polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. A review

The usual methods for determining polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) are generally expensive and time consuming. This fact has favored the development of faster and cheaper techniques, based on immunoassays and bioassays. This paper reviews these bioanalytical methods and their analytical importance at the present moment.     

二类广义Vandermonde行列式的计算

给出了二类广义Vandermonde行列式计算的显式表示式.     

Circadian synchrony in networks of protein rhythm driven neurons

The interaction between gene activation and cellular activity has recently emerged as a critical aspect of brain behavior, but the dynamics of networks incorporating these interactions are poorly understood. An interesting phenomena arises when the genetic activation oscillates endogenously and a network of such cells synchronize to a coherent rhythm, such as is the case with the suprachiasmatic nucleus. To explain this synchronization, we propose a model in which a mRNA/protein expression cycle drives neurons electrical activity, and synaptic activation shifts the phase of the protein rhythm. Using lattice networks, we demonstrate that these interactions are sufficient to generate coherent oscillation. © 2006 Wiley Periodicals, Inc. Complexity 12: 67–72, 2006     

Finite‐difference approximation for the u(k)‐derivative with O(hM−k+1) accuracy: An analytical expression

An approximation of function u(x) as a Taylor series expansion about a point x₀ at M points x_i, ～ i = 1,2,…,M is used where x_i are arbitrary‐spaced. This approximation is a linear system for the derivatives u^(k) with an arbitrary accuracy. An analytical expression for the inverse matrix A ^?1 where A = [A_ik] = (x_i ? x₀)^k is found. A finite‐difference approximation of derivatives u^(k) of a given function u(x) at point x₀ is derived in terms of the values u(x_i). © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006     

对称常微分算子的两种自伴延拓形式之间的联系

建立了对称常微分算子von N eum ann自伴延拓与以边条件形式表达的自伴延拓之间的对应关系,给出了相互转换的方法.     

Regular expression constrained sequence alignment

We introduce regular expression constrained sequence alignment as the problem of finding the maximum alignment score between given strings $S_1$ and $S_2$ over all alignments such that in these alignments there exists a segment where some substring $s_1$ of $S_1$ is aligned to some substring $s_2$ of $S_2$, and both $s_1$ and $s_2$ match a given regular expression R, i.e. $s_1,s_2\in L(R)$ where $L(R)$ is the regular language described by R. For complexity results we assume, without loss of generality, that $n=|S_1|⩾|m|=|S_2|$. A motivation for the problem is that protein sequences can be aligned in a way that known motifs guide the alignments. We present an $\mathrm{O}(nmr)$ time algorithm for the regular expression constrained sequence alignment problem where $r=\mathrm{O}(t^4)$, and t is the number of states of a nondeterministic finite automaton N that accepts $L(R)$. We use in our algorithm a nondeterministic weighted finite automaton M that we construct from N. M has $\mathrm{O}(t^2)$ states where the transition-weights are obtained from the given costs of edit operations, and state-weights correspond to optimum alignment scores we compute using the underlying dynamic programming solution for sequence alignment. If we are given a deterministic finite automaton D accepting $L(R)$ with $t_d$ states then our construction creates a deterministic finite automaton $M_d$ with $t_d^2$ states. In this case, our algorithm takes $\mathrm{O}(t_d^{2}nm)$ time. Using $M_d$ results in faster computation than using M when $t_d<t^2$. If we only want to compute the optimum score, the space required by our algorithm is $\mathrm{O}(t^{2}n)$ ($\mathrm{O}(t_d^{2}m)$ if we use a given $M_d$). If we also want to compute an optimal alignment then our algorithm uses $\mathrm{O}(t^{2}m+t^2|s_1||s_2|)$ space ($\mathrm{O}(t_d^{2}m+t_d^2|s_1||s_2|)$ space if we use a given $M_d$) where $s_1$ and $s_2$ are substrings of $S_1$ and $S_2$, respectively, $s_1,s_2\in L(R)$, and $s_1$ and $s_2$ are aligned together in the optimal alignment that we construct. We also show that our method generalizes for the case of the problem with affine gap penalties, and for finding optimal regular expression constrained local sequence alignments.     

昆虫细胞凋亡蛋白酶caspase-1的表达纯化及活性分析

依赖于天冬氨酸的半胱氨酸蛋白酶(caspase)在细胞凋亡途径中起着不可替代的关键酶作用.本研究采用原核表达载体pET32a表达和纯化了家蚕细胞Bm-caspase-1及粉纹夜蛾细胞Tni-caspase-1蛋白酶,序列分析表明二者具有相同的内部剪切识别序列,且酶活性位点均为QACQ↓G.纯化获得大量可溶性蛋白酶,Western-blotting分析表明Bm-caspase-1在大肠杆菌中已自我剪切活化,而Tni-caspase-1没有自我剪切,无酶活性;活性Bm-caspase-1蛋白酶对caspase-3特异性底物Ac-DEVD-AMC的降解酶活性可被Z-VAD-FMK呈剂量依赖性抑制,半抑制浓度约20nmol/L.此外,活性Bm-caspase-1蛋白酶能够转活化无活性的Tni-caspase-1蛋白酶原.结果揭示了昆虫细胞caspase同样具有与哺乳动物细胞caspase相似的底物降解活性并可相互剪切激活,为进一步研究昆虫细胞凋亡的分子途径奠定了基础.     

用类实现数学表达式屏幕输入的C++程序

给出了数学表达式屏幕输入的C^ 程序,并用类进行了封装．封装之后,成了一个独立模块．以Newton求根迭代程序为例说明,该模块可以方便地嵌入在需要它的其他程序里．