Development of ultra-high-performance supercritical fluid chromatography-mass spectrometry assays to analyze potential biomarkers in sweat

Liquid chromatography-mass spectrometry methods were required to afford the rapid separation and detection of purines and small organic acids. These compounds are found in sweat and sebum and are potential biomarkers for the early detection of pressures sores. Two ultra-high-performance supercritical fluid chromatography-mass spectrometry assays have been successfully developed for both classes of compounds. Separation for purines was achieved using a gradient of supercritical carbon dioxide and methanol with a 1-aminoanthracene sub 2 μm particle size column followed by positive ion electrospray ionization. Separation for organic acids was achieved using a gradient of supercritical carbon dioxide and methanol (50 mM ammonium acetate 2% water) with a Diol sub 2 μm particle size column followed by negative ion electrospray ionization. Calibration curves were created in the absence of internal standards and R² values > 0.96 were achieved using single ion monitoring methods for the protonated purines and the deprotonated acids. The two new assays afford rapid analytical methods for the separation and detection of potential biomarkers in human sweat leading to the early detection and prevention of pressure sores.     

求解复杂湍流的非线性涡黏性系数模型和代数应力模型

非线性涡黏性系数模型和代数应力模型联系了线性涡黏性系数湍流模型和完整的微分 雷诺应力模型.随着它们受到日益关注,其形式也越来越多样化.本篇综述的目的是对这些模 型加以总结并比较它们之间的共同点及不同之处,指出它们与完整微分雷诺应力模型之间的 关系,以及相对于线性涡黏性系数模型而言它们在预报流场上所具有的优势.     

On differential polynomials, fixpoints and critical values of meromorphic functions

We prove some results concerning functions ? meromorphic of finite lower order in the plane, such that ??″?α(?′)² has few zeros, where α is a constant, using in part new estimates for the multipliers at fixpoints of certain functions. We go on to consider zeros of derivatives and the minimal lower growth of meromorphic functions with finitely many critical values.     

Erkennung des Pikrotoxins

Ohne Zusammenfassung     

Zero-angle depolarized light scattering of a colloidal polymer

The potential of zero-angle depolarized scattering for measuring the size distributions of optically anisotropic particles is considered. To illustrate the method, an analysis of Fluon, a teflon latex suspension, is presented. Homodyne correlation functions having signal-to-noise characteristics every bit as good as conventional unpolarized finite-angle measurements enabled confident application of a smoothed exponential sampling algorithm to obtain the decay rate distribution, which was converted to a size distribution with certain approximations. The size distribution obtained from light scattering agrees well with that from electron microscopy.     

Sound radiation from a vibrating plate with uncertainty

Sound radiation into open space from a vibrating structure has been investigated since Rayleigh. On the other hand the sound power transferring into neighboring reverberant subsystems has also been rigorously studied using statistical energy analysis, particularly for the high frequency range. Falling between the two well-known problems, pressure and intensity fields from the sound radiation have not yet been widely studied using statistical methods. In this paper, the sound radiation from a vibrating thin plate having uncertain dynamic properties is investigated. Estimates are developed for the reverberant vibration field in the uncertain plate subjected to a point-excitation, and for the ensemble average of pressure from the direct field and from the reverberant field, leading to an estimate of the average sound intensity. The power radiated from the plate and the radiation efficiency is also derived. Monte Carlo simulations are conducted with an ensemble of plates with randomly-distributed point masses, and the simulation results compare well with the estimates.     

Numerical and experimental validation of variance prediction in the statistical energy analysis of built-up systems

In the statistical energy analysis (SEA) approach to vibration modeling, a complex system is represented as an assembly of coupled subsystems, and the method leads to the prediction of the vibrational energy level of each subsystem. The averaging procedures implicit in the technique imply that the predicted energy is the mean value taken over an ensemble of random structures, such as a set of vehicles leaving a production line. Recently, a new method has been developed to allow the ensemble variance, in addition to the mean, to be predicted within the context of SEA, and the present paper concerns further extension and validation of this work. The theoretical extension concerns the variance of the energy density at a single point in any of the subsystems, and the validation includes both simulation and experimental studies. The simulation results concern plate assemblies, while experimental results are presented both for a single-plate and for a cylinder-plate structure. In each case an ensemble of random structures has been generated by adding small point masses at random locations on the structure. In general, good agreement between the predictions and the validation results is observed.