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Preliminary Application (preliminary + application)
Selected AbstractsPreliminary application of processed electroencephalogram monitoring to differentiate senile dementia from depressionPSYCHOGERIATRICS, Issue 3 2009Norihito OSHIMA Abstract Background:, It is difficult, but important, to distinguish between dementia and depression in old age because senile depression has atypical symptoms, including cognitive impairment and memory disorder. Now brain computed tomography, magnetic resonance imaging, single photon emission computed tomography, and positron emission tomography can be used to differentiate between these two conditions. However, these methods are expensive and not always available. In the present case series, we assessed the potential of monitoring the bispectral index to distinguish between dementia and depression. Methods:, A processed electroencephalogram monitor (bispectral index (BSI) monitor) was used to assess brain activity during relaxed wakefulness in 12 participants (seven with Alzheimer's disease (AD), three with depression, and two healthy volunteers). Each recording lasted 5 min and four variables (i.e. BSI, 95% spectral edge frequency, electromyogram activity, and signal quality index) were monitored. Results:, The BSI was significantly smaller in AD patients than in patients with depression (P < 0.05) and the 95% spectral edge frequency tended to be lower in AD patients than in patients with depression (P = 0.26). Slow waves were found in patients with AD and beta waves were predominant in patients with depression and healthy volunteers. Conclusion:, In conclusion, the BSI and 95% spectral edge frequency were slightly smaller in dementia patients than in patients with depression. Paroxysmal slow waves may account for the low bispectral index. Thus, BSI monitoring may become a useful tool with which to distinguish AD from depression. [source] Enhanced docking with the mining minima optimizer: Acceleration and side-chain flexibilityJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 16 2002Visvaldas Kairys Abstract The ligand,protein docking algorithm based on the Mining Minima method has been substantially enhanced. First, the basic algorithm is accelerated by: (1) adaptively determining the extent of each energy well to help avoid previously discovered energy minima; (2) biasing the search away from ligand positions at the surface of the receptor to prevent the ligand from staying at the surface when large sampling regions are used; (3) quickly testing multiple different ligand positions and orientations for each ligand conformation; and (4) tuning the source code to increase computational efficiency. These changes markedly shorten the time needed to discover an accurate result, especially when large sampling regions are used. The algorithm now also allows user-selected receptor sidechains to be treated as mobile during the docking procedure. The energies associated with the mobile side chains are computed as if they belonged to the ligand, except that atoms at the boundary between side chains and the rigid backbone are treated specially. This new capability is tested for several well-known ligand/protein systems, and preliminary application to an enzyme whose substrate is unknown,the recently solved hypothetical protein YecO (HI0319) from Haemophilus influenzae,indicates that side-chains relaxations allow candidate substrates of various sizes to be accommodated. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1656,1670, 2002 [source] Diffusion imaging in humans at 7T using readout-segmented EPI and GRAPPAMAGNETIC RESONANCE IN MEDICINE, Issue 1 2010Robin M. Heidemann Abstract Anatomical MRI studies at 7T have demonstrated the ability to provide high-quality images of human tissue in vivo. However, diffusion-weighted imaging at 7T is limited by the increased level of artifact associated with standard, single-shot, echo-planar imaging, even when parallel imaging techniques such as generalized autocalibrating partially parallel acquisitions (GRAPPA) are used to reduce the effective echo spacing. Readout-segmented echo-planar imaging in conjunction with parallel imaging has the potential to reduce these artifacts by allowing a further reduction in effective echo spacing during the echo-planar imaging readout. This study demonstrates that this approach does indeed provide a substantial improvement in image quality by reducing image blurring and susceptibility-based distortions, as well as by allowing the acquisition of diffusion-weighted images with a high spatial resolution. A preliminary application of the technique to high-resolution diffusion tensor imaging provided a high level of neuroanatomical detail, which should prove valuable in a wide range of applications. Magn Reson Med 64:9,14, 2010. © 2010 Wiley-Liss, Inc. [source] Matching the frequency spectrum of pre-main sequence stars by means of standard and rotating modelsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008M. Di Criscienzo ABSTRACT We applied the aton evolutionary code to the computation of detailed grids of standard (non-rotating) and rotating pre-main sequence (PMS) models and computed their adiabatic oscillation spectra, with the aim of exploring the seismic properties of young stars. As, until now, only a few frequencies have been determined for ,40 PMS stars, the way of approaching the interpretation of the oscillations is not unique. We adopt a method similar to the matching mode method by Guenther and Brown making use, when necessary, also of our rotating evolutionary code to compute the models for PMS stars. The method is described by a preliminary application to the frequency spectrum of two PMS stars (85 and 278) in the young open cluster NGC 6530. For the Star 85, we confirm with self-consistent rotating models, previous interpretation of the data, attributing three close frequencies to the mode n= 4, l= 1 and m= 0, +1 and ,1. For the Star 278, we find a different fit for the frequencies, corresponding to a model within the original error box of the star, and dispute the possibility that this star has a Teff much cooler that the red boundary of the radial instability strip. [source] Application of hyphenated mass spectrometry techniques for the analysis of urinary free glucocorticoidsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2009Angela Cuzzola Alteration of levels of glucocorticoids in plasma and urine can be related to several diseases. In particular, the determination of endogenous glucocorticoids in urine has been reported to provide information on cortisol and cortisone status, on the activities of steroid hormone enzymes and on glucocorticoid metabolism. In this study, the application of hyphenated mass spectrometry techniques (GC/MS without derivatization and LC/MS) for the simultaneous analysis of free urinary cortisol (F), cortisone (E), tetrahydrocortisol (THF), allo-tetrahydrocortisol (A-THF) and tetrahydrocortisone (THE) was evaluated. A sample preparation protocol by solid-phase extraction, mass spectrometry parameters and chromatographic conditions for both techniques were carefully optimized in terms of extracting phase and solvents, matrix effects, recovery, sensitivity and compound resolution. Baseline separation was achieved for the five underivatized analytes both in GC and LC. The LC/MS/MS technique was more suitable for the analysis of urine samples, being less influenced by matrix effects and showing excellent sensitivity and selectivity. A preliminary application of the reported method for the diagnosis of metabolic diseases was also described. The determination of each analyte in its free form, described for the first time in the paper, offers new perspectives in the application of glucocorticoid analysis for diagnostic purposes. Copyright © 2009 John Wiley & Sons, Ltd. [source] Fiber tracking using magnetic resonance diffusion tensor imaging and its applications to human brain developmentDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 3 2003Richard Watts Abstract Diffusion tensor imaging is unique in its ability to noninvasively visualize white matter fiber tracts in the human brain in vivo. Diffusion is the incoherent motion of water molecules on a microscopic scale. This motion is itself dependent on the micro-structural environment that restricts the movement of the water molecules. In white matter fibers there is a pronounced directional dependence on diffusion. With white matter fiber tracking or tractography, projections among brain regions can be detected in the three-dimensional diffusion tensor dataset according to the directionality of the fibers. Examples of developmental changes in diffusion, tracking of major fiber tracts, and examples of how diffusion tensor tractography and functional magnetic resonance imaging can be combined are provided. These techniques are complimentary and allow both the identification of the eloquent areas of the brain involved in specific functional tasks, and the connections between them. The noninvasive nature of magnetic resonance imaging will allow these techniques to be used in both longitudinal developmental and diagnostic studies. An overview of the technique and preliminary applications are presented, along with its current limitations. MRDD Research Reviews 2003;9:168,177. © 2003 Wiley-Liss, Inc. [source] Evaluation of use of a very short polar microbore column segment in high-speed gas chromatography analysisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2008Peter Quinto Tranchida Abstract Very fast GC analyses are commonly carried out by using 10 m×0.1 mm id capillaries. In order to achieve rapid elution times (1,3 min), the latter are operated under suboptimum conditions. The present research is focused on the evaluation of use of a 0.1 mm id polar column segment (2 m), operated under near-to-optimum conditions, in very fast GC analysis. The results attained are compared with those derived from using a 10 m microbore column in very fast GC experiments. Prior to method development, the effects of gas velocity, temperature program rate, and sample amounts on analytical performance were evaluated. Following these preliminary applications, a complex lipidic sample, cod liver oil, was subjected to rapid separation (,2.1 min) on the 10 m capillary through the application of a 50°C/min temperature rate and a 130 cm/s gas velocity. The same matrix was analyzed on the 2 m capillary using the same temperature program rate and range, but with a close-to-ideal linear velocity. The results observed were of interest, as the separation was achieved in less time (1.45 min) with improved peak resolution. Finally, both methods were validated in terms of retention time and peak area repeatability, LOQ, and linearity. [source] | |||||||||||||