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Metabolomics research often requires the use of multiple analytical platforms, batches of samples, and laboratories, any of which can introduce a component of unwanted variation. In addition, every experiment is subject to within-platform and other experimental variation, which often includes unwanted biological variation. Such variation must be removed in order to focus on the biological information of interest. We present a broadly applicable method for the removal of unwanted variation arising from various sources for the identification of differentially abundant metabolites and, hence, for the systematic integration of data on the same quantities from different sources. We illustrate the versatility and the performance of the approach in four applications, and we show that it has several advantages over the existing normalization methods. [ABSTRACT FROM AUTHOR]

A method is described for the rapid identification of oligosaccharides employing a library of tandem MS spectra. Identification is aided by software that compares the sample tandem MS to those in the library. The method incorporates quadrupole time-of-flight mass spectrometry along with an annotated oligosaccharide (OS) structure library and the MassHunter Personal Compound Database and Library (PCDL) software. With an automated spectra search, OS structures in different samples are readily identified. This method is shown to be useful in the study of milk oligosaccharides but can be readily applied to oligosaccharide pools in other biological tissues. [ABSTRACT FROM AUTHOR]

Abstract: Gas chromatography coupled to mass spectrometry (GC/MS) is a core analytical method for metabolomics and has been used as a platform in non-targeted analysis, especially for hydrophilic metabolites. Non-targeted GC/MS-based metabolomics generally requires a high-throughput technology to handle a large volume of samples and an accumulated database (reference library) of the retention times and mass spectra of standard compounds for accurate peak identification. In this study, we provide a practical GC/MS platform and an auto peak identification technique that is not restricted to certain types of mass spectrometers. The platform utilizes a quadrupole mass spectrometer capable of high-speed scanning, resulting in greater output compared with Pegasus GC-time of flight (TOF)/MS, which has been an essential instrument for high-throughput experiments. Moreover, we show that our reference library is broadly applicable to other instruments; peak identification can be readily performed using the library without constructing a reference resource. The usefulness and versatility of our system are demonstrated by the analyses of three experimental metabolomics data sets, including standard mixtures and real biological samples. [Copyright &y& Elsevier]

The wheel-drive system of a car has a major influence on the safety of car's occupants. By turning the steering wheel, centrifugal forces are developed and these forces cause a bending moment on the rack steering gear. To avoid plastic deformation of the rack steering gear, sufficient strength and spring/stiffness properties are necessary for the material. In the case under investigation, the vehicle was traveling with 60 km/h on a slippery road. While negotiating a turn along the road, the driver was not able to bring the car back on the road. The car stopped without any crash, and the technical inspection which followed showed that the rack steering gear was deformed plastically at the right arm. The occupants were in great danger during this incident. Metallurgical failure analysis was conducted, revealing that plastic deformation by bending occurred because the mechanical properties of the steel were not adequate because of insufficient deoxidation practices and a defective hard coating. The lack of deoxidation and defects in the hard coating should not be allowed occur, and to avoid such failures, the quality control measures for acceptance of such parts should be modified. The new practices should include better control over the non-metallic inclusions, and measurement of the hard coating's thickness over the whole length of the bar. [ABSTRACT FROM AUTHOR]

Abstract: The time and height at the peak maximum are key parameters to describe a chromatographic peak with prediction or optimization purposes, or in the qualitative/quantitative analysis of samples. Three different approaches to estimate these parameters, using the experimental points in the peak maximum region, are here described and compared. The approaches are based on the reliable description of the peak profile using a modified Gaussian model with a parabolic variance (PVMG). In the first approach, non-linear fitting of the chromatographic data to the PVMG model is carried out to obtain the time and height at the peak maximum (Approach I). In the other two approaches, the PVMG model is linearized to carry out a linear fitting. In each case, the optimal number of processed points was assessed. The three approaches yielded highly satisfactory results, being Approach I the best in terms of accuracy and robustness. The assessment of the accuracy in the estimations was carried out using simulated peaks. These peaks were built with the parameters obtained from real peaks for several probe compounds eluted under reversed-phase liquid chromatographic (RPLC) conditions, to which noise was added. [Copyright &y& Elsevier]