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Simple Design (simple + design)
Selected AbstractsInvestigating DNA migration in pulsed fields using a miniaturized FIGE systemELECTROPHORESIS, Issue 23 2008Xiaojia Chen Abstract PFGE is a well-established technique for fractionation of DNA fragments ranging from kilobases to megabases in length. But many of these separations require an undesirable combination of long experiment times (often approaching tens of hours) and application of high voltages (often approaching tens of kV). Here, we present a simple miniaturized FIGE apparatus capable of separating DNA fragments up to 32.5,kb in length within 3,h using a modest applied potential of 20,V. The device is small enough to be imaged under a fluorescence microscope, permitting the migrating DNA bands to be observed during the course of the separation run. We use this capability to investigate how separation performance is affected by parameters including the ratio of forward and backward voltage, pulse time, and temperature. We also characterize the dependence of DNA mobility on fragment size N, and observe a scaling in the vicinity of N,0.5 over the size range investigated. The high speed, low power consumption, and simple design of this system may help enable future studies of DNA migration in PFGE to be performed quickly and inexpensively. [source] High-efficiency peptide analysis on monolithic multimode capillary columns: Pressure-assisted capillary electrochromatography/capillary electrophoresis coupled to UV and electrospray ionization-mass spectrometryELECTROPHORESIS, Issue 21 2003Alexander R. Ivanov Abstract High-efficiency peptide analysis using multimode pressure-assisted capillary electrochromatography/capillary electrophoresis (pCEC/pCE) monolithic polymeric columns and the separation of model peptide mixtures and protein digests by isocratic and gradient elution under an applied electric field with UV and electrospray ionization-mass spectrometry (ESI-MS) detection is demonstrated. Capillary multipurpose columns were prepared in silanized fused-silica capillaries of 50, 75, and 100 ,m inner diameters by thermally induced in situ copolymerization of methacrylic monomers in the presence of n -propanol and formamide as porogens and azobisisobutyronitrile as initiator. N -Ethylbutylamine was used to modify the chromatographic surface of the monolith from neutral to cationic. Monolithic columns were termed as multipurpose or multimode columns because they showed mixed modes of separation mechanisms under different conditions. Anion-exchange separation ability in the liquid chromatography (LC) mode can be determined by the cationic chromatographic surface of the monolith. At acidic pH and high voltage across the column, the monolithic stationary phase provided conditions for predominantly capillary electrophoretic migration of peptides. At basic pH and electric field across the column, enhanced chromatographic retention of peptides on monolithic capillary column made CEC mechanisms of migration responsible for separation. The role of pressure, ionic strength, pH, and organic content of the mobile phase on chromatographic performance was investigated. High efficiencies (exceeding 300,000 plates/m) of the monolithic columns for peptide separations are shown using volatile and nonvolatile, acidic and basic buffers. Good reproducibility and robustness of isocratic and gradient elution pressure-assisted CEC/CE separations were achieved for both UV and ESI-MS detection. Manipulation of the electric field and gradient conditions allowed high-throughput analysis of complex peptide mixtures. A simple design of sheathless electrospray emitter provided effective and robust low dead volume interfacing of monolithic multimode columns with ESI-MS. Gradient elution pressure-assisted mixed-mode separation CE/CEC-ESI-MS mass fingerprinting and data-dependent pCE/pCEC-ESI-MS/MS analysis of a bovine serum albumin (BSA) tryptic digest in less than 5 min yielding high sequence coverage (73%) demonstrated the potential of the method. [source] Optical CDMA codes for use in a lightwave communication network with multiple data rates,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 3 2002Jian-Guo Zhang This paper presents a new kind of optical code-division multiple-access (CDMA) codes, called unequal-length optical orthogonal codes (UL-OOC's), for multirate data communications. The autocorrelation and cross-correlation functions of UL-OOC's are dependent only on each individual codeword, in spite of either an aperiodic or a periodic pulse-sequence pattern at the input of optical CDMA decoders. This property can be thus used to support multirate data communications in a lightwave network, without any violation of the minimum correlation constraint (i.e., "1") for incoherent optical processing. Theory and simple design of UL-OOC's are presented. Applications of the proposed codes to multirate optical CDMA is also explained in detail. [source] MUEBLES RÚSTICOS IN MEXICO AND THE UNITED STATESGEOGRAPHICAL REVIEW, Issue 3 2002Article first published online: 21 APR 2010, JOHN HARNER ABSTRACT. Sales of muebles rústicos, or rustic wooden furniture made in Mexico, have grown rapidly in the United States since 1994. Analysis of the recent rise of the industry tracks manufacturing and marketing methods in major production areas of Mexico. Consumer taste for "authentic" handmade goods of simple design and the vogue of the "Santa Fe" style across the American Southwest mesh with Mexican producers' need to seek foreign markets during an economic crisis. Changing style preferences, along with the furniture's handcrafted appearance, its competitive cost, and the makers' flexible production methods, are reasons for the increased popularity of this folk commodity. [source] Clear strategy screens for macromolecular crystallizationJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2001Andrzej Marek Brzozowski The development of high-throughput crystallography combined with the wealth of already accumulated information about protein crystallization properties requires constant revision of current crystallization screening procedures. Two complementary 6 × 4 matrix `clear strategy screens' (CSS) have been developed and tested on a number of previously non-crystallized proteins. The screens yielded diffraction-quality crystals of a wide range of proteins (enzymes, transcription factors, structural proteins, etc.) in cases where the applications of commercially available screens were unsuccessful. Both their inherently simple design and their flexible nature provide an experimenter with a logical platform for further modification and optimization. Furthermore, the screens facilitate cryoprotection and potential incorporation of anomalous scatterers for multiple/single-wavelength anomalous dispersion (MAD/SAD) experiments. [source] Multi-wavelength fiber laser in the S-band region using a Sagnac loop mirror as a comb generator in an SOA gain mediumLASER PHYSICS LETTERS, Issue 9 2010M.Z. Zulkifii Abstract A simple design of multi-wavelength generation in the S-band region of the optical network transmission is proposed. The design consists of broad-band fiber Bragg grating (BB-FBG), which acts as a filter to enhance operation in the S-band region. A Sagnac loop mirror (SLM) is used to generate multiple wavelength oscillations in the ring cavity. The output consists of 60 lasing wavelengths oscillating simultaneously between 1464 nm and 1521 nm with a spacing of 0.92 nm and an output linewidth of 0.66 nm. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] An X-band microstrip oscillator integrated with frequency-selecting patch antennaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2009D. H. Lee Abstract A simple design for microstrip oscillator consisting of an active source and an output patch antenna is presented. The active source is designed to possess negative-resistance over broad bandwidth but not to oscillate without the output patch antenna. Two different source circuits that are potentially unstable over full C-band and X-band are fabricated. Six different-size patch antennas are then connected with each source circuit to demonstrate the oscillation frequency control. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1963,1966, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24481 [source] High-quality surface passivation of silicon solar cells in an industrial-type inline plasma silicon nitride deposition systemPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 1 2004Jens D. Moschner Abstract We have studied the surface passivation of silicon by deposition of silicon nitride (SiN) in an industrial-type inline plasma-enhanced chemical vapor deposition (PECVD) reactor designed for the continuous coating of silicon solar cells with high throughput. An optimization study for the passivation of low-resistivity p -type silicon has been performed exploring the dependence of the film quality on key deposition parameters of the system. With the optimized films, excellent passivation properties have been obtained, both on undiffused p -type silicon and on phosphorus-diffused n+ emitters. Using a simple design, solar cells with conversion efficiencies above 20% have been fabricated to prove the efficacy of the inline PECVD SiN. The passivation properties of the films are on a par with those of high-quality films prepared in small-area laboratory PECVD reactors. Copyright © 2004 John Wiley & Sons, Ltd. [source] Construction and Performance of a Minibioreactor Suitable as Experimental Bioartificial LiverARTIFICIAL ORGANS, Issue 4 2008Joaquín V. Rodriguez Abstract:, This work deals with the construction and performance of a hollow fiber-based minibioreactor (MBR). Due to its simple design and the utilization of standard materials, it could serve as a suitable tool to evaluate the behavior and performance of cold preserved or cultured hepatocytes in bioartificial liver devices. The system consists of 140 fiber capillaries through which goat blood is pumped at a flow of 9 mL/min. The cell compartment contains 90 × 106 rat hepatocytes (volume 10 mL) and an internal oxygenator made of silicone tubing. To test the in vitro function of the system, 2-h perfusion experiments were performed, the evolution of hematocrit, plasma and extra-fiber fluid osmolality, and plasma urea and creatinine concentrations were evaluated. The detoxication efficiency of an ammonia overload was tested, showing that the system has enough capacity to remove ammonium. Also, the MBR oxygen transfer capacity to hepatocytes was tested, showing that the cells received an adequate oxygen supply. [source] Breaking symmetry in protein dimers: Designs and functionsPROTEIN SCIENCE, Issue 1 2006Jerry H. Brown Abstract Symmetry, and in particular point group symmetry, is generally the rule for the global arrangement between subunits in homodimeric and other oligomeric proteins. The structures of fragments of tropomyosin and bovine fibrinogen are recently published examples, however, of asymmetric interactions between chemically identical chains. Their departures from strict twofold symmetry are based on simple and generalizable chemical designs, but were not anticipated prior to their structure determinations. The current review aims to improve our understanding of the structural principles and functional consequences of asymmetric interactions in proteins. Here, a survey of >100 diverse homodimers has focused on the structures immediately adjacent to the twofold axis. Five regular frameworks in ,-helical coiled coils and antiparallel ,-sheets accommodate many of the twofold symmetric axes. On the basis of these frameworks, certain sequence motifs can break symmetry in geometrically defined manners. In antiparallel ,-sheets, these asymmetries include register slips between strands of repeating residues and the adoption of different side-chain rotamers to avoid steric clashes of bulky residues. In parallel coiled coils, an axial stagger between the ,-helices is produced by clusters of core alanines. Such simple designs lead to a basic understanding of the functions of diverse proteins. These functions include regulation of muscle contraction by tropomyosin, blood clot formation by fibrin, half-of-site reactivity of caspase-9, and adaptive protein recognition in the matrix metalloproteinase MMP9. Moreover, asymmetry between chemically identical subunits, by producing multiple equally stable conformations, leads to unique dynamic and self-assembly properties. [source] | |||||||||||||