Rapid characterization of Bacillus spores targeting species-unique peptides produced with an atmospheric pressure matrix-assisted laser desorption/ionization source

New and improved strategies are eagerly sought for the rapid identification of microorganisms, particularly in mixtures. Mass spectrometry remains a powerful tool for this purpose. Small acid-soluble proteins (SASPs), which are relatively abundant in Bacillus spores, represent potential biomarkers for species characterization. Despite sharing extensive sequence homology, these proteins differ sufficiently in sequence for discrimination between species. This work focuses on the differences in sequence between SASPs from various Bacillus species. Compilation of SASP sequences from protein database searches, followed by in silico trypsin digestion and analysis of the resulting fragments, identified several species-specific peptides that could be targeted for analysis using mass spectrometry. This strategy was tested and found to be successful in the characterization of Bacillus spores both from individual species and in mixtures. Analysis was performed using an ion trap mass spectrometer with an atmospheric pressure MALDI source. This instrumentation offers the advantage of increased speed of analysis and accurate precursor ion selection for tandem mass spectrometric analysis compared with vacuum matrix-assisted laser desorption/ionization and time-of-flight instruments. The identification and targeting of species-specific peptides using this type of instrumentation offers a rapid, efficient strategy for the identification of Bacillus spores and can potentially be applied to different microorganisms.     

2-Compressible non-Heegaard surfaces in small 3- manifolds

In the present paper, we investigate the non-Heegaard 2-compressible surfaces in small 3-manifolds, and show that such surfaces have some good properties.     

A Functional LIL for Stochastic Integrals and the Lévy Area Process

A functional law of the iterated logarithm is obtained for processes given by certain stochastic integrals. This extends earlier results by Shi⁽¹²⁾ and Rémillard⁽¹⁰⁾ who established analogues of the classical limit results of Chung⁽⁴⁾ for a variety of processes, including Lévys stochastic area process. The functional aspects of our results are motivated by a paper of Wichura⁽¹³⁾ on Brownian motion. Proofs depend on small ball probability estimates, and yield the small ball probabilities of the weighted sup-norm for the processes given by these stochastic integrals.     

Theoretical calculation of electron-impact resonance excitation of alkali atoms

Total cross-section for electron impact excitation of the resonance levels in Li, Na and K are calculated using the method due to Crothers and McCarroll. The results are compared with other available theoretical and experimental data.     

The translation-rotation paradox in the nucleation theory

The factor of 10¹⁷ proposed by Lothe and Pound in the theory of nucleation of droplets from the vapor phase is studied using classical statistical mechanics. The controversial factor is derived from partition functions for an isolatedn-mer and for ann-molecular cluster imbedded in the bulk liquid phase. The rotational degrees of freedom have no place in, in agreement with Reiss, Katz, and Cohen's treatment. It is proved that the surface free energy of a cluster is proportional to the surface area. The estimate of what Lothe and Pound called the replacement term is different from those of previous authors. It is concluded that is written as a ratio = _g/_l, where _g and _l , are the volumes per molecule in the gas phase and in the liquid phase, respectively. For water at 300K, is approximately equal to 10₄.     

非线性Schrōdinger方程和非线性Klein-Gordon方程耦合组Cauchy问题整体经典解的存在唯一性

本文讨论非线性Schrōdinger方程和非线性Klein-Gordon方程耦合组的Cauchy问题,对初值和空间维数以及非线性项加以适当限制,在Sobolev空间框架下,得到了整体经典解的存在唯一性。     

Use of pseudopotential towards time-evolution of a nonstationary state: Spatially localized excitation in a crystal

Pseudopotential is used as a formal operator to write the exact time-dependence of a pseudoexciton and hence that of an initial excitation spatially localized in a crystal. The exponential operator where pseudopotential occurs at the argument is readily evaluated using the property of projection operators. Migration of an initially localized excitation is of considerable experimental importance and can be of conceptual use since it should eventually generate the characteristics of a migrating exciton. From the formal time-dependence of a localized excitation, its spread with time can be calculated with relative ease. In a concurrent discussion, the previous work of Merrifield (1958) on the propagation of excitation is criticized and an error is pointed out. The spread, however, remains wavelike and is not dissipative in the absence of a collisional mechanism.     

预给二面角的单形在球面型空间Sn,r的嵌入

本文获得预给二面角的单形嵌入球面型空间Ｓ_n,r的一个充分必要条件，并利用它得到关于球面单形二面角的两类几何不等式。     

弹簧耦合摆小振动的简正模与简正频率

将耦合摆弹簧作为弹性均匀杆，导出了对称简正模与反对称简正模的本征方程，给出各角频率值的近似式，并进行了讨论。