Capillary HPLC Separation of Selected Neuropeptides

Neuropeptides play a pivotal role in brain and peripheral nervous system function. As high performance liquid chromatography (HPLC) becomes the central tool in the separation and characterization of peptide and protein samples, its selectivity optimization has attracted increasing attention. This research program aims to develop useful, quantitative analysis methods for neuropeptides and their hydrolysis fragments by capillary HPLC. Related peptide pairs are successfully separated, such as leu-enkephalin and [Des-Tyr1] leu-enkephalin, dynorphin A and dynorphin B, galanin and its fragment Gal1-16. The hydrolysis of leu-enkephalin to [Des-Tyr1] leu-enkephalin by organotypic hippocampal slice cultures (OHSCs) can be monitored by the same HPLC system. The separation of seven hippocampal neuropeptides with similar hydrophobicity, Bj-PRO-5a, [Des-Tyr1] leu-enkephalin, leu-enkephalin, pentagastrin, Antho-RW-amide I, dynorphin A 1-6 and angiotensin II, is accomplished by thermally tuned tandem capillary columns (T3C). The chromatographic selectivity is continuously, systematically and significantly optimized by individual adjustment of each column’s temperature. The T3C concept is applied for the first time with capillary columns, which is an important step towards optimization of selectivity for separations of small samples by liquid chromatography

Sizes of Lightest Glueballs in SU(3) Lattice Gauge Theory

Standard Monte Carlo simulations have been performed on improved lattices to measure the wave functions and sizes of the scalar and tensor glueballs at four lattice spacings in the range $a= 0.05 - 0.145$ fm. Systematic errors from discretization and finite volume are studied. Our results in the continuum limit show that the size of the tensor state is approximately two times as large as that of the scalar glueball.Comment: 7 pages, 6 figures. Accepted for publication. To appear in Prog. Theor. Phys. Vol. 116, No. 1 (2006

Project benefit management: a conceptual framework of target benefit formulation

Successful realization of project benefits is strongly associated with organizational performance. Formulating project target benefits is regarded as the first and critical step in the benefit management process. In this study, we drew upon relevant theories and conducted in-depth interviews with senior managers in Australia to develop a conceptual framework of project target benefit formulation and corresponding propositions. Our findings highlight the important role of project target benefits in funding decision-making and suggest seven criteria for their appraisal (strategic fit, target value, measurability, realism, target date, accountability and comprehensiveness) and four constructs which improve the formulated target benefits (a formal benefit formulation process, senior executive leadership, senior executive supports, and public service motivation). These findings extend the current literature on project benefit management by providing a holistic view on how project target benefits should be formulated and appraised

Event History Analysis of Dynamic Communication Networks

Statistical analysis on networks has received growing attention due to demand from various emerging applications. In dynamic networks, one of the key interests is to model the event history of time-stamped interactions amongst nodes. We propose to model dynamic directed communication networks via multivariate counting processes. A pseudo partial likelihood approach is exploited to capture the network dependence structure. Asymptotic results of the resulting estimation are established. Numerical results are performed to demonstrate effectiveness of our proposal