Identification of Nitrotyrosine Containing Peptides using Combined Fractional Diagonal Chromatography (COFRADIC) and Off-Line Nano-LC-MALDI

Protein nitration take place on tyrosine residues under oxidative stress conditions and may influence a number of processes including enzyme activity, protein-protein interactions and phospho-tyrosine signalling pathways. Nitrated proteins have been identified in a number of diseases, however, the study of these proteins has been compromised by the lack of good methods for identifying nitrated proteins, their nitration sites and the level of nitration. Here, we present a method for identification of nitrated peptides that allows the site specific assignment of nitration, is easy to use and reproducible, and opens up for the possibility to quantify the level of nitration of specific peptides as function of different oxidative conditions, namely combined fractional diagonal chromatography (COFRADIC) in combination with off-line nano-LC-MALDI. We identify six nitrated peptides from in vitro nitrated bovine serum albumin and propose that automated COFRADIC using nano-LC and off-line MALDI-MS might be a possibility for identification of tyrosine nitrated proteins and the nitration sites in complex samples.     

Simple Zeros of the Riemann Zeta-Function

Assuming the Riemann Hypothesis, Montgomery showed by meansof his pair correlation method that at least two-thirds of thezeros of Riemann's zeta-function are simple. Later he and Taylorimproved this to 67.25 percent and, more recently, Cheer andGoldston increased the percentage to 67.2753. Here we proveby a new method that if the Riemann and Generalized LindelöofHypotheses hold, then at least 70.3704 percent of the zerosare simple and at least 84.5679 percent are distinct. Our methoduses mean value estimates for various functions defined by Dirichletseries sampled at the zeros of the Riemann zeta-function. 1991Mathematics Subject Classification: 11M26.     

Existence and Uniqueness of Fixed Points for Markov Operators and Markov Processes

This paper concerns a Markov operator T on a space L₁, and aMarkov process P which defines a Markov operator on a spaceM of finite signed measures. For T, the paper presents necessaryand sufficient conditions for:

a the existence of invariant probabilitydensities (IPDs)

b the existence of strictly positive IPDs,and

c the existence and uniqueness of IPDs.

Similar resultson invariant probability measures for P are presented. The basicapproach is to pose a fixed-point problem as the problem ofsolving a certain linear equation in a suitable Banach space,and then obtain necessary and sufficient conditions for thisequation to have a solution. 1991 Mathematics Subject Classification:60J05, 47B65, 47N30.     

Elastic constants of some nematic liquid crystals with banana-shaped molecules

Results are given for the elastic constants in the nematic phase of some molecules with a curved (banana-like) molecular shape. In principle this could lead to a reduced bend elastic constant due to the possibility of adjusting to a bend deformation by a redistribution of the molecules. However, the elastic constants turn out to have quite normal values as compared with similar non-curved molecules.     

库仑加线性位基态解析解

应用新发展的单一轨迹积分方法求解库仑加线性位的基态量子波函数,得到基态能量和波函数的一般解析表达式,并讨论了解的收敛性.应用此方法讨论了重夸克偶素系统.     

Self-assembled growth of nanostructural Ge islands on bromine-passivated Si(111) surfaces at room temperature

We have deposited relatively thick (∼60 nm) Ge layers on Br-passivated Si(111) substrates by thermal evaporation under high vacuum conditions at room temperature. Ge has grown in a layer-plus-island mode although it is different from the Stranski-Krastanov growth mode observed in epitaxial growth. Both the islands and the layer are nanocrystalline. This appears to be a consequence of reduction of surface free energy of the Si(111) substrate by Br-passivation. The size distribution of the Ge nanoislands has been determined. The Br-Si(111) substrates were prepared by a liquid treatment, which may not produce exactly reproducible surfaces. Nevertheless, some basic features of the nanostructural island growth are reasonably reproducible, while there are variations in the details of the island size distribution.