Homo-DNA templated chemistry and its application to nucleic acid sensing

We have investigated the homo-DNA templated Staudinger reduction of the profluorophore rhodamine azide and have applied this reaction to the detection of natural DNA with a hybrid homo-DNA/DNA molecular beacon. In this system the sensing and the reporting unit are bioorthogonal to each other which facilitates sequence design and increases fidelity.     

Periodic orbit analysis demonstrates genetic constraints, variability, and switching in Drosophila courtship behavior

We use symbolic dynamics to describe Drosophila courtship communication. We posit that behavior should be defined in terms of irreducible periodic orbits of fundamental acts. This leads to a first operational definition of behavior, which allows for a fine grained quantitative analysis of behavior. We obtain evidence that during Drosophila courtship, individual characteristics of the protagonists are exchanged (predominantly from the male to the female) and that males in the presence of fruitless males perform a behavioral switch from male to female behavior.     

LIFA System for Fluorescence Lifetime Imaging Microscopy (FLIM)

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LIFA System for Fluorescence Lifetime Imaging Microscopy (FLIM)     

多噪声源共同作用下的总烦恼度评价与预测

主要研究了多噪声源共同作用下的混合噪声烦恼度的评价过程与预测方法. 首先, 设计并完成了固定播放时长噪声样本作用下的烦恼度主观评价实验, 获得了人工合成的混合噪声样本作用下的混合噪声烦恼度(亦称总烦恼度) α_T 评价数据与构成混合噪声样本的所有单一噪声样本单独作用时的烦恼度α_i (i=1, 2, 3, ···, K; K为混合噪声样本中单一噪声样本的总数) 评价数据. 随后, 细致分析了两组评价数据之间的关系, 提出在已知α_i 的基础上利用多元线性回归模型预测α_T. 最后, 解决了如何确定模型中对应各α_i的权值ω_i (i=1, 2, 3, ···, K) 的问题. 研究表明, 以所提出的权值确定方法建立的多元线性回归预测模型 能够较为成功地预测混合噪声样本作用下的总烦恼度评价值.     

Packing of elastic wires in spherical cavities

We investigate the morphologies and maximum packing density of thin wires packed into spherical cavities. Using simulations and experiments, we find that ordered as well as disordered structures emerge, depending on the amount of internal torsion. We find that the highest packing densities are achieved in low torsion packings for large systems, but in high torsion packings for small systems. An analysis of both situations is given in terms of energetics and comparison is made to analytical models of DNA packing in viral capsids.     

Exact complexity of the logistic map

The relation between chaotic behavior and complexity for one-dimensional maps is discussed. The one-dimensional maps are mapped into a binary string via symbolic dynamics in order to evaluate the complexity. We apply the complexity measure of Lempel and Ziv to these binary strings. To characterize the chaotic behavior, we calculate the Liapunov exponent. We show that the exact normalized complexity for the logistic mapf: [0,1]→[0,1],f(x)=4x(1−x) is given by 1.     

Chemical Etiology of Nucleic Acid Structure: The Pentulofuranosyl Oligonucleotide Systems: The (1′→3′)‐β‐L‐Ribulo, (4′→3′)‐α‐L‐Xylulo,and (1′→3′)‐α‐L‐Xylulo Nucleic Acids

Under potentially prebiotic scenarios, ribose (pentose), the component of RNA is formed in meager amounts, as opposed to ribulose and xylulose (pentuloses). Consequently, replacement of ribose in RNA, with pentulose sugars, gives rise to prospective oligonucleotide candidates that are potentially prebiotic structural variants of RNA that could be formed by the same type of chemical pathways that gave rise to RNA from ribose. The potentially natural alternative (1′→3′)‐ribulo oligonucleotides and (4′→3′)‐ and (1′→3′)‐xylulo oligonucleotides consisting of adenine and thymine were synthesized and found to exhibit no self‐pairing or cross‐pairing with RNA. This signifies that even though pentulose sugars may have been abundant in a prebiotic scenario, the pentulose nucleic acids (NAs), if and when formed, would not have been competitors of RNA, or interfered with the emergence of RNA as a functional informational system. The reason for the lack of base pairing in pentulose NA highlights the contrasting and central role played by the furanosyl ring in RNA and pentulose NA, enabling and optimizing the base pairing in RNA, while impeding it in pentulose NA.