Considerations for quantification of lipids in nerve tissue using matrix-assisted laser desorption/ionization mass spectrometric imaging

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging is a technique that provides the ability to identify and characterize endogenous and exogenous compounds spatially within tissue with relatively little sample preparation. While it is a proven methodology for qualitative analysis, little has been reported for its utility in quantitative measurements. In the current work, inherent challenges in MALDI quantification are addressed. Signal response is monitored over successive analyses of a single tissue section to minimize error due to variability in the laser, matrix application, and sample inhomogeneity. Methods for the application of an internal standard to tissue sections are evaluated and used to quantify endogenous lipids in nerve tissue. A precision of 5% or less standard error was achieved, illustrating that MALDI imaging offers a reliable means of in situ quantification for microgram-sized samples and requires minimal sample preparation.     

Use of a Single Capillary Electrophoresis Method as a Routine Identity Test for Batch Release of a Range of Pharmaceutical Products

Two independent and orthogonal analytical methods are required when performing identity testing of pharmaceutical products during routine release testing. A microemulsion electrokinetic chromatography method has been developed and validated for routine use as an identity test to release various pharmaceutical products including tablets, capsules and creams. Implementation of the method involved optimisation of parameters to achieve reliable routine operation. Rinsing procedures, in particular, were found to be essential to obtain consistent profiles and migration times. The method has replaced, and offers the potential to replace, a number of methods including HPLC and IR due to the considerable cost and time savings obtained through its use. This method has been successfully approved by the US FDA as a part of 2 New Drug Applications, is registered in Japan, and is in routine QA use within a factory environment.     

Source motion mitigation for adaptive matched field processing

Application of adaptive matched field processing to the problem of detecting quiet targets in shallow water is complicated by source motion, both the motion of the target and the motion of discrete interferers. Target motion causes spreading of the target peak, thereby reducing output signal power. Interferer motion increases the dimensionality of the interference subspace, reducing adaptive interference suppression. This paper presents three techniques that mitigate source motion problems in adaptive matched field processing. The first involves rank reduction, which enables adaptive weight computation over short observation intervals where motion effects are less pronounced. The other two techniques specifically compensate for source motion. Explicit target motion compensation reduces target motion mismatch by focusing snapshots according to a target velocity hypothesis. And time-varying interference filtering places time-varying nulls on moving interferers not otherwise suppressed by adaptive weights. The three techniques are applied to volumetric array data from the Santa Barbara Channel Experiment and are shown to improve output signal-to-background-plus-noise ratio by more than 3 dB over the standard minimum-variance, distortionless response adaptive beam-former. Application of the techniques in some cases proves to be the difference between detecting and not detecting the target.     

Asymmetric alkylation of diarylmethane derivatives. Improved results using methoxyethoxy substituent

Alkylation of 2-methoxyethoxyphenyl phenyl methane using sec-BuLi and (−)-sparteine has been carried out in excellent yields and up to 94% ee. The best results were obtained in allylation reactions but methylation, ethylation, benzylation and trimethylsilylation have all been carried out with acceptable ee.     

Bond Index Funds — A Duration Approach

Index funds can be used by investment managers as a method of ensuring that their portfolio performs as well as the general market. Methods have been proposed for creating index funds for the stock market, and in this paper a method for creating an index fund for a sector of the bond market is suggested. The underlying indexing mechanism uses the duration moments of the portfolio to capture the various aspects of the sector and its response to changes in the yield curve. The initial results suggest that a relatively small basic set of bonds can be used to model the movements of a particular market segment.     

Heteroaryl substituted ansa‐titanocene anti‐cancer drugs derived from fulvenes and titanium dichloride

Starting from 2‐furylfulvene (1a) , 2‐thiophenylfulvene (1b) , and 1‐methyl‐2‐pyrrolylfulvene (1c), [1,2‐di(cyclopentadienyl)‐1,2‐di‐(2‐furyl)ethanediyl] titanium dichloride (2a) , [1,2‐di(cyclopentadienyl)‐1,2‐di‐(2‐thiophenyl)ethanediyl] titanium dichloride (2b) , and [1,2‐di(cyclopentadienyl)‐1,2‐bis‐(1‐methyl‐2‐pyrrolyl)ethanediyl] titanium dichloride (2c) were synthesized. When titanocenes (2a–c) were tested against pig kidney carcinoma cells (LLC‐PK), inhibitory concentrations (50%) of 4.5 × 10^?4 M , 2.9 × 10^?4 M and 2.0 × 10^?4 M respectively were observed. Copyright © 2005 John Wiley & Sons, Ltd.     

Unbalanced bipartite factorizations of complete bipartite graphs

We construct a new infinite family of factorizations of complete bipartite graphs by factors all of whose components are copies of a (fixed) complete bipartite graph K_p,q. There are simple necessary conditions for such factorizations to exist. The family constructed here demonstrates sufficiency in many new cases. In particular, the conditions are always sufficient when q=p+1.     

Multinuclear NMR study of phosphosilicate gels derived from POCl3 and Si(OC2H5)4

Solid state ¹H, ²⁹Si and ³¹P MAS NMR have been used to investigate the microstructure of phosphosilicate gels prepared by a modified sol-gel method involving hydrolysis of silicon precursors in a solely aqueous environment at 50 °C. Gels with molar compositions 5, 10, 20 and 30 mol% P₂O₅ in P₂O₅-SiO₂ were studied. After drying to 400 °C the gels have very similar structures formed by a siloxane framework containing silanol groups and trapped molecules of orthophosphoric acid together with a very small amount, of pyrophosphoric acid. Unlike the gel samples previously synthesized by the hydrolysis of the silicon precursor in alcoholic solution at room temperature, the co-polymerization of phosphorus and silicon is much reduced. Although co-polymerization increases with phosphorus content, it still represents less than 50% of the phosphorus in the 30 mol% P₂O₅ gel. Furthermore there is no evidence for six-coordinated silicon in the glassy matrix.