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Substantial Enhancement (substantial + enhancement)
Selected AbstractsAmperometric Detection of 4-Chlorophenol on Two Types of Expanded Graphite Based Composite ElectrodesELECTROANALYSIS, Issue 22 2008Aniela Pop Abstract The assessment of an expanded graphite-Ag-zeolite-epoxy composite (EG-Z-Ag-Epoxy) electrode for the determination of 4-chlorophenol (4-CP) is described and compared to the corresponding expanded graphite-epoxy composite (EG-Epoxy) electrode. Cyclic voltammetry was used to characterize the electrochemical behavior and determination of 4-CP at both electrodes in 0.1,M Na2SO4 and 0.1,M NaOH supporting electrolytes. A substantial enhancement of sensitivity for the determination of 4-CP at the EG-Z-Ag-Epoxy electrode was reached by applying a chemical preconcentration step prior to voltammetric quantification. Also, under these last conditions the lowest limit of detection of 1,,M illustrates the analytical versatility of this electrode in a concentration range where aquatic 4-chlorophenol pollution is known to occur. [source] DNase I hypersensitive sites and transcriptional activation of the lamin A/C geneFEBS JOURNAL, Issue 5 2000Kazuhiko Nakamachi The lamin A/C gene encodes subtypes of nuclear lamins, which are involved in nuclear envelope formation, and was recently identified as the responsible gene for the autosomal dominant Emery,Dreifuss muscular dystrophy. Expression of the lamin A/C gene is developmentally regulated but little is known about the regulatory mechanism. Previous studies of lamin A/C expression suggested that the chromatin structure is important for the regulation of its expression. To elucidate the regulatory mechanism of the lamin A/C gene expression, we have analysed the functional region of the mouse lamin A/C promoter and the chromatin structure of the gene in terms of nucleosome structure and DNase I hypersensitivity. Our analyses revealed disruption of the nucleosome array at the promoter region and the presence of multiple DNase I hypersensitive sites (HSs) which were specifically associated with expression of the lamin A/C gene. Inclusion of a segment which contained the HSs in a lamin A/C promoter-luciferase reporter plasmid showed no effect on the transfected promoter activity in transient expression assays. On the other hand, substantial enhancement of the promoter activity was detected when the transfected DNA was stably integrated into the genome, suggesting the importance of the HSs in the regulation of lamin A/C expression. [source] Enhanced visualization of histological samples with an adjustable RGB contrast system with application for tissue used in photodynamic therapyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 6 2008Wilma Regina Barrionuevo Abstract The analysis of histological sections has long been a valuable tool in the pathological studies. The interpretation of tissue conditions, however, relies directly on visual evaluation of tissue slides, which may be difficult to interpret because of poor contrast or poor color differentiation. The Chromatic Contrast Visualization System (CCV) combines an optical microscope with electronically controlled light-emitting diodes (LEDs) in order to generate adjustable intensities of RGB channels for sample illumination. While most image enhancement techniques rely on software post-processing of an image acquired under standard illumination conditions, CCV produces real-time variations in the color composition of the light source itself. The possibility of covering the entire RGB chromatic range, combined with the optical properties of the different tissues, allows for a substantial enhancement in image details. Traditional image acquisition methods do not exploit these visual enhancements which results in poorer visual distinction among tissue structures. Photodynamic therapy (PDT) procedures are of increasing interest in the treatment of several forms of cancer. This study uses histological slides of rat liver samples that were induced to necrosis after being exposed to PDT. Results show that visualization of tissue structures could be improved by changing colors and intensities of the microscope light source. PDT-necrosed tissue samples are better differentiated when illuminated with different color wavelengths, leading to an improved differentiation of cells in the necrosis area. Due to the potential benefits it can bring to interpretation and diagnosis, further research in this field could make CCV an attractive technique for medical applications. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc. [source] Microfluidics-based electrospray ionization enhances the intrasource separation of lipid classes and extends identification of individual molecular species through multi-dimensional mass spectrometry: development of an automated high-throughput platform for shotgun lipidomicsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2008Xianlin Han Herein, we exploit the use of microfluidics and optimized Taylor cones for improved intrasource separation/selective ionization of lipid classes during electrospray ionization. Increased differential ionization of multiple phospholipid classes was achieved through microfluidics with chip-based ionization resulting in substantial enhancement of intrasource separation/selective ionization of phospholipid classes in comparison to the conventional ion source. For example, using myocardial lipid extracts, 3-fold improvements in intrasource separation/selective ionization of myocardial phospholipid classes were routinely realized in the negative-ion mode in the absence of LiOH or other basic modifiers in the infused sample solutions. Importantly, the relative ratios of ions corresponding to individual molecular species in each lipid class to a selected internal standard from myocardial extracts were nearly identical between the chip-based interface and the syringe-pump-driven capillary interface. Therefore, quantitation of individual lipid molecular species directly from biological extracts through comparisons with internal standards in each lipid class was readily accomplished with an accuracy and dynamic range nearly identical to those documented using the well-established direct syringe-pump-driven capillary interface. Collectively, the use of microfluidics and robotic sample handling substantially enhances intrasource separation of lipids in comparison to routine capillary interfaces and greatly facilitates the use of multi-dimensional mass spectrometry using shotgun lipidomics, thereby providing an automated and high-throughput platform for global analyses of cellular lipidomes. Copyright © 2008 John Wiley & Sons, Ltd. [source] AN EFFICIENT MODEL FOR ENHANCING TEXT CATEGORIZATION USING SENTENCE SEMANTICSCOMPUTATIONAL INTELLIGENCE, Issue 3 2010Shady Shehata Most of text categorization techniques are based on word and/or phrase analysis of the text. Statistical analysis of a term frequency captures the importance of the term within a document only. However, two terms can have the same frequency in there documents, but one term contributes more to the meaning of its sentences than the other term. Thus, the underlying model should identify terms that capture the semantics of text. In this case, the model can capture terms that present the concepts of the sentence, which leads to discovering the topic of the document. A new concept-based model that analyzes terms on the sentence, document, and corpus levels rather than the traditional analysis of document only is introduced. The concept-based model can effectively discriminate between nonimportant terms with respect to sentence semantics and terms which hold the concepts that represent the sentence meaning. A set of experiments using the proposed concept-based model on different datasets in text categorization is conducted in comparison with the traditional models. The results demonstrate the substantial enhancement of the categorization quality using the sentence-based, document-based and corpus-based concept analysis. [source] | ||||||||||