991 research outputs found

    Solar Panel with Embedded Electronics

    Get PDF
    Currently, inverters are needed to utilize solar panels for applications that require AC power. Unfortunately, these inverters are very costly and decrease power efficiency. In this work, two alternatives to using inverters are explored. The first method combines a buck converter with a buck-boost converter to create a sine output. The second method uses switches to change the connections of the solar cells, producing a stepped AC output. Both methods involve embedding the solar cells along with the additional electronics into a solar panel, thus eliminating the need for a separate inverter. Simulations were performed using SIMPLIS, and both methods were compared with a focus on feasibility and cost. Results of the simulation demonstrated that the DC-DC converter method performs better than the multiple switch method. More specifically, the quality of the sinusoidal output voltage from the DC-DC converter method is better than the stepped sine wave produced by the multiple switches. Furthermore, the use of many switches to produce a sine wave like output makes the multiple switch method not practical due to the complexity of circuit as well as cost. Therefore, through these comparisons, we recommend that future projects should focus on implementing prototypes for the DC-DC converter method using buck buck-boost converter

    Synthesis, structural studies, and oxidation catalysis of the late-first-row-transition-metal complexes of a 2-pyridylmethyl pendant-armed ethylene cross-bridged cyclam

    Get PDF
    The first 2-pyridylmethyl pendant-armed ethylene cross-bridged cyclam ligand has been synthesized and successfully complexed to MnĀ²āŗ, FeĀ²āŗ, CoĀ²āŗ, NiĀ²āŗ, CuĀ²āŗ, and ZnĀ²āŗ cations. X-ray crystal structures were obtained for all six complexes and demonstrate pentadentate binding of the ligand with the requisite cis-V configuration of the cross-bridged cyclam ring in all cases, leaving a potential labile binding site cis to the pyridine donor for interaction of the complex with oxidants and/or substrates. The electronic properties of the complexes were evaluated using solid-state magnetic moment determination and acetonitrile solution electronic spectroscopy, which both agree with the crystal structure determination of high-spin divalent metal complexes in all cases. Cyclic voltammetry in acetonitrile revealed reversible redox processes in all but the NiĀ²āŗ complex, suggesting that catalytic reactivity involving electron-transfer processes is possible for complexes of this ligand. Kinetic studies of the dissociation of the ligand from the copper(II) complex under strongly acidic conditions and elevated temperatures revealed that the pyridine pendant arm actually destabilizes the complex compared to the parent cross-bridged cyclam complex. Screening for oxidation catalysis using hydrogen peroxide as the terminal oxidant for the most biologically relevant MnĀ²āŗ, FeĀ²āŗ, and CuĀ²āŗ complexes identified the MnĀ²āŗ complex as a potential mild oxidation catalyst worthy of continued development

    Heidelberg Anterion Swept-Source OCT Corneal Epithelial Thickness Mapping: Repeatability and Agreement With Optovue Avanti

    Get PDF
    PURPOSE: To assess the repeatability of corneal epithelial thickness mapping in virgin, post-laser refractive surgery (PLRS), and keratoconic eyes using a novel swept-source optical coherence tomographer (SS-OCT), and to determine the agreement of the measurements with a validated spectral-domain (SD) OCT. METHODS: Analysis of 90 virgin, 46 PLRS, and 122 keratoconic eyes was performed. Three consecutive measurements of each eye were acquired with the Anterion SS-OCT and Avanti SD-OCT devices, and averages of the epithelial thickness mapping were calculated in the central 2-mm zone and in the 2- to 5-mm and 5- to 7-mm diameter rings. The repeatability was analyzed using pooled within-subject standard deviation (Sw). The agreement was assessed by Bland-Altman analysis and paired t tests. RESULTS: The repeatability ranges of the Anterion and Avanti epithelial thickness mapping measurements were Sw: 0.60 to 1.36 Āµm and Sw: 0.75 to 1.96 Āµm, respectively. The 95% limits of agreement of the Anterion and Avanti were 0.826 to 8.297. All values of the thickness measurements with the Anterion were lower than those of the Avanti, with the mean differences being 4.06 Ā± 1.81, 3.26 Ā± 2.52, and 3.68 Ā± 2.51 Āµm in virgin, PLRS, and keratoconic eyes, respectively (P < .001 for all). CONCLUSIONS: The repeatability of the Anterion's epithelial thickness mapping was higher than that of the Avanti. In terms of the agreement between the Anterion and Avanti, the epithelium measured by the Anterion was always thinner than that of the Avanti, making their interchangeable use unsuitable without corrections

    Transformational dynamics of BZO and BHO nanorods imposed by Y2O3 nanoparticles for improved isotropic pinning in YBa2Cu3O7āˆ’Ī“ thin films

    Get PDF
    An elastic strain model was applied to evaluate the rigidity of the c-axis aligned one-dimensional artificial pinning centers (1D-APCs) in YBa2Cu3O7-Ī“ matrix films. Higher rigidity was predicted for BaZrO3 1D-APCs than that of the BaHfO3 1D-APCs. This suggests a secondary APC doping of Y2O3 in the 1D-APC/YBa2Cu3O7-Ī“ nanocomposite films would generate a stronger perturbation to the c-axis alignment of the BaHfO3 1D-APCs and therefore a more isotropic magnetic vortex pinning landscape. In order to experimentally confirm this, we have made a comparative study of the critical current density Jc (H, Īø, T) of 2 vol.% BaZrO3 + 3 vol.%Y2O3 and 2 vol.%BaHfO3 + 3 vol.%Y2O3 double-doped (DD) YBa2Cu3O7-Ī“ films deposited at their optimal growth conditions. A much enhanced isotropic pinning was observed in the BaHfO3 DD samples. For example, at 65 K and 9.0 T, the variation of the Jc across the entire Īø range from Īø=0 (H//c) to Īø=90 degree (H//ab) is less than 18% for BaHfO3 DD films, in contrast to about 100% for the BaZrO3 DD counterpart. In addition, lower Ī± values from the Jc(H) āˆ¼ H-Ī± fitting were observed in the BaHfO3 DD films in a large Īø range away from the H//c-axis. Since the two samples have comparable Jc values at H//c-axis, the improved isotropic pinning in BaHfO3 DD films confirms the theoretically predicted higher tunability of the BaHfO3 1D-APCs in APC/YBa2Cu3O7-Ī“ nanocomposite films

    Using the TAP Component of the Antigen-Processing Machinery as a Molecular Adjuvant

    Get PDF
    We hypothesize that over-expression of transporters associated with antigen processing (TAP1 and TAP2), components of the major histocompatibility complex (MHC) class I antigen-processing pathway, enhances antigen-specific cytotoxic activity in response to viral infection. An expression system using recombinant vaccinia virus (VV) was used to over-express human TAP1 and TAP2 (VV-hTAP1,2) in normal mice. Mice coinfected with either vesicular stomatitis virus plus VV-hTAP1,2 or Sendai virus plus VV-hTAP1,2 increased cytotoxic lymphocyte (CTL) activity by at least 4-fold when compared to coinfections with a control vector, VV encoding the plasmid PJS-5. Coinfections with VV-hTAP1,2 increased virus-specific CTL precursors compared to control infections without VV-hTAP1,2. In an animal model of lethal viral challenge after vaccination, VV-hTAP1,2 provided protection against a lethal challenge of VV at doses 100-fold lower than control vector alone. Mechanistically, the total MHC class I antigen surface expression and the cross-presentation mechanism in spleen-derived dendritic cells was augmented by over-expression of TAP. Furthermore, VV-hTAP1,2 increases splenic TAP transport activity and endogenous antigen processing, thus rendering infected targets more susceptible to CTL recognition and subsequent killing. This is the first demonstration that over-expression of a component of the antigen-processing machinery increases endogenous antigen presentation and dendritic cell cross-presentation of exogenous antigens and may provide a novel and general approach for increasing immune responses against pathogens at low doses of vaccine inocula

    ReCoil - an algorithm for compression of extremely large datasets of dna data

    Get PDF
    The growing volume of generated DNA sequencing data makes the problem of its long term storage increasingly important. In this work we present ReCoil - an I/O efficient external memory algorithm designed for compression of very large collections of short reads DNA data. Typically each position of DNA sequence is covered by multiple reads of a short read dataset and our algorithm makes use of resulting redundancy to achieve high compression rate

    DODO: an efficient orthologous genes assignment tool based on domain architectures. Domain based ortholog detection

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Orthologs are genes derived from the same ancestor gene loci after speciation events. Orthologous proteins usually have similar sequences and perform comparable biological functions. Therefore, ortholog identification is useful in annotations of newly sequenced genomes. With rapidly increasing number of sequenced genomes, constructing or updating ortholog relationship between all genomes requires lots of effort and computation time. In addition, elucidating ortholog relationships between distantly related genomes is challenging because of the lower sequence similarity. Therefore, an efficient ortholog detection method that can deal with large number of distantly related genomes is desired.</p> <p>Results</p> <p>An efficient ortholog detection pipeline DODO (DOmain based Detection of Orthologs) is created on the basis of domain architectures in this study. Supported by domain composition, which usually directly related with protein function, DODO could facilitate orthologs detection across distantly related genomes. DODO works in two main steps. Starting from domain information, it first assigns protein groups according to their domain architectures and further identifies orthologs within those groups with much reduced complexity. Here DODO is shown to detect orthologs between two genomes in considerably shorter period of time than traditional methods of reciprocal best hits and it is more significant when analyzed a large number of genomes. The output results of DODO are highly comparable with other known ortholog databases.</p> <p>Conclusions</p> <p>DODO provides a new efficient pipeline for detection of orthologs in a large number of genomes. In addition, a database established with DODO is also easier to maintain and could be updated relatively effortlessly. The pipeline of DODO could be downloaded from <url>http://140.109.42.19:16080/dodo_web/home.htm</url></p
    • ā€¦
    corecore