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Technological Improvements (technological + improvement)
Selected AbstractsEfficient cloning of plant genomes into bacterial artificial chromosome (BAC) libraries with larger and more uniform insert sizePLANT BIOTECHNOLOGY JOURNAL, Issue 3 2004Boulos Chalhoub Summary The construction of bacterial artificial chromosome (BAC) libraries remains relatively complex and laborious, such that any technological improvement is considered to be highly advantageous. In this study, we addressed several aspects that improved the quality and efficiency of cloning of plant genomes into BACs. We set the ,single tube vector' preparation method with no precipitation or gel electrophoresis steps, which resulted in less vector DNA damage and a remarkable two- to threefold higher transformation efficiency compared with other known vector preparation methods. We used a reduced amount of DNA for partial digestion (up to 5 µg), which resulted in less BAC clones with small inserts. We performed electrophoresis in 0.25 × TBE (Tris, boric acid, ethylenediaminetetraacetic acid) buffer instead of 0.5 × TBE, which resulted in larger and more uniformly sized BAC inserts and, surprisingly, a two- to threefold higher transformation efficiency, probably due to less contamination with borate ions. We adopted a triple size selection that resulted in an increased mean insert size of up to 70 kb and a transformation efficiency comparable with that of double size selection. Overall, the improved protocol presented in this study resulted in a five- to sixfold higher cloning efficiency and larger and more uniformly sized BAC inserts. BAC libraries with the desired mean insert size (up to 200 kb) were constructed from several plant species, including hexaploid wheat. The improved protocol will render the construction of BAC libraries more available in plants and will greatly enhance genome analysis, gene mapping and cloning. [source] Fast Batch to Continuous Transposition: Application to the Extraction of Andrographolide from PlantsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2006L. Prat Abstract A fast development method for batch to continuous process transposition is proposed. This method is based on transient regime experiment analyses and is applied to a solid-liquid extraction. The application under consideration is the extraction of an active principle from a plant in a non-sinusoidal pulsed column. Typically, the proposed signal is composed of two different periods: firstly, a classical sinusoidal pulsation step is used to mix the liquid and solid phases in the active part of the column and allow an optimal mass transfer and, secondly, an impulsion phase, used generally for the transport of solids. The extraction is carried out in a disc and doughnut column of 54,mm diameter and 3.5,m height. Liquid and solid are flowing co-currently and downwardly. This technological improvement has been implemented to solve the difficulties due to the significant heterogeneity of the matter: one part tends to float and other to sink, which always leads to a definitive flooding in classical operations. The effects of the solid flow rate and the solvent characteristics on the hydrodynamic behavior of the column are studied. The mean residence time and the total solid holdup are calculated by using a transient regime mass balance on the experimental results. These experiments allow the identification and quantification of opposite effects of the operating parameters. Mass transfer experiments have been performed and the results fit calculated values obtained by coupling the hydrodynamic and batch extraction results. Despite the simplifications made, this validates the fast development method proposed to help batch to continuous transposition. [source] Virtual microscopy: An educator's tool for the enhancement of cytotechnology students' locator skillsDIAGNOSTIC CYTOPATHOLOGY, Issue 6 2008Jimmie Stewart III M.D. Abstract Virtual microscopy (VM) is being utilized as an educational tool in many areas of pathology. The aim of this study is to analyze the locator and diagnostic skills of cytotechnology students by using the Aperio T3 ScanScope®, and examine VM's viability as an educational tool in cytotechnology. Ten validated cytology slides were digitized and reviewed by three senior cytotechnologist instructors. Each technologist made annotations indicating diagnostic areas on the virtual slide. A subset of the slides was used for locator skill evaluation. Cytotechnology students examined a pristine copy of the virtual slide and made annotations for comparison to those made by experienced instructors. Annotations of the subset were then scored based on the degree of correlation between students and cytotechnologists. A cytopathologist performed a final review of the students' marks; points were then added or subtracted based on this interpretation. Students were graded based on their correlation to senior cytotechnologists. A statistical analysis using modified interrater calculations ranked the students as to locator ability, producing illuminating results. This study shows that VM has promise as a cytotechnology educational tool by allowing the instructor to evaluate students' locator and diagnostic abilities. We have attempted to implement a simple scoring system for evaluation of locator skills where students are compared versus expert cytotechnologists. We anticipate further technological improvements as the products mature. Diagn. Cytopathol. 2008;36:363,368. © 2008 Wiley-Liss, Inc. [source] Capillary columns in liquid chromatography: between conventional columns and microchipsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17-18 2004Yoshihiro Saito Abstract Liquid chromatography on columns with small internal diameters has been reviewed as the intermediate technique between conventional liquid chromatography and microchip separations. The development of micro column separations in the early years has been described, starting with the papers of Horváth and co-workers and Ishii and co-workers, continuing into the first part of the eighties, then making a leap in time to recent innovations with small-bore columns. Based on internal diameters a classification of the different analytical HPLC columns has been suggested. The advantages of small-bore columns have been discussed, with particular emphasis on the advantage of coupling to concentration sensitive detectors when the sample amount is limited. Open tubular columns are treated as a part of the historic background. The recent developments include a brief look into the current status of monolithic columns, the use of packed nano columns and micro columns with electrospray mass spectrometry, and the potential of two-dimensional comprehensive liquid chromatography. Finally, the coupling of sample preparation to analytical columns and the future applications of the novel technological improvements to the microchip separation methods have been discussed. [source] An automated tracking system to measure the dynamic properties of vesicles in living cellsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2007Tien-Chuan Ku Abstract Recent technological improvements have made it possible to examine the dynamics of individual vesicles at a very high temporal and spatial resolution. Quantification of the dynamic properties of secretory vesicles is labor-intensive and therefore it is crucial to develop software to automate the process of analyzing vesicle dynamics. Dual-threshold and binary image conversion were applied to enhance images and define the areas of objects of interest that were to be tracked. The movements, changes in fluorescence intensity, and changes in the area of each tracked object were measured using a new software system named the Protein Tracking system (PTrack). Simulations revealed that the system accurately recognized tracked objects and measured their dynamic properties. Comparison of the results from tracking real time-lapsed images manually with those automatically obtained using PTrack revealed similar patterns for changes in fluorescence intensity and a high accuracy (<89%). According to tracking results, PTrack can distinguish different vesicular organelles that are similar in shape, based on their unique dynamic properties. In conclusion, the novel tracking system, PTrack, should facilitate automated quantification of the dynamic properties of vesicles that are important when classifying vesicular protein locations. Microsc. Res. Tech. 2007. © 2006 Wiley-Liss, Inc. [source] Offline, multidetector intensity interferometers , I. TheoryMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006Aviv Ofir ABSTRACT Stellar amplitude interferometry is limited by the need to have optical distances fixed and known to a fraction of the wavelength. We suggest reviving intensity interferometry, which requires hardware which is many orders of magnitude less accurate, at the cost of more limited sensitivity. We present an algorithm to use the very high redundancy of a uniform linear array to increase the sensitivity of the instrument by more than a 100-fold. When using an array of 100 elements, each almost 100 m in diameter, and conservative technological improvements, we can achieve a limiting magnitude of about mb= 14.4. Digitization, storage, and offline processing of all the data will also enable interferometric image reconstruction from a single observation run, and application of various algorithms at any later time. Coronagraphy, selectively suppressing only the large-scale structure of the source, can be achieved by specific aperture shapes. We conclude that after three decades of abandonment optical intensity interferometry deserves another review. [source] Quality of protein crystal structuresACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2007Eric N. Brown The genomics era has seen the propagation of numerous databases containing easily accessible data that are routinely used by investigators to interpret results and generate new ideas. Most investigators consider data extracted from scientific databases to be error-free. However, data generated by all experimental techniques contain errors and some, including the coordinates in the Protein Data Bank (PDB), also integrate the subjective interpretations of experimentalists. This paper explores the determinants of protein structure quality metrics used routinely by protein crystallographers. These metrics are available for most structures in the database, including the R factor, Rfree, real-space correlation coefficient, Ramachandran violations etc. All structures in the PDB were analyzed for their overall quality based on nine different quality metrics. Multivariate statistical analysis revealed that while technological improvements have increased the number of structures determined, the overall quality of structures has remained constant. The quality of structures deposited by structural genomics initiatives are generally better than the quality of structures from individual investigator laboratories. The most striking result is the association between structure quality and the journal in which the structure was first published. The worst offenders are the apparently high-impact general science journals. The rush to publish high-impact work in the competitive atmosphere may have led to the proliferation of poor-quality structures. [source] REVIEW: Nonpharmacological Therapies for Atrial FibrillationCARDIOVASCULAR THERAPEUTICS, Issue 5 2010Mark Alber Meshil SUMMARY In recent years, nonpharmacological therapies for atrial fibrillation (AF) have emerged given the limitations of medical therapy. Advancements in particular have been made in the areas of radiofrequency catheter ablation and AF surgery, and have been accompanied by substantial technological improvements. This article will discuss several different modalities of nonpharmacological AF management including catheter ablation, AF surgery and device-based therapy. [source] | |||||||||||||