193 research outputs found

    Effect of LaAlO3_3 Surface Topography on RF Current Distribution in Superconducting Microwave Devices

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    A laser scanning microscope with a thermal spot size of about 4 μ\mum is used to measure a quantity proportional to the rf current density in an operating superconducting co-planar waveguide microwave resonator. The twinning of the LaAlO3_3 substrate produces a meandering of the current at the edges due to irregularities in the wet etching of the YBa2_2Cu3_3O7−δ_{7-\delta} film associated with substrate twin domain blocks, and a (∼\sim 20%) enhancement of the rf photoresponse at these locations. These irregularities are candidates for enhanced nonlinear response from the device. The effects of substrate twinning and the resulting edge features on the superconducting film are discussed and analyzed.Comment: 13 pages, 4 figures, submitted to Applied Physics Letter

    A continuous compositional-spread technique based on pulsed-laser deposition and applied to the growth of epitaxial films

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    A novel continuous-compositional spread technique based on the non-uniformity of the deposition rate typically observed in Pulsed Laser Deposition (PLD) is introduced. The approach uses the spatial variations in the deposition-rate naturally occurring in PLD; therefore, there is no need for the masks typically used in combinatorial techniques. Consequently, combinatorial materials synthesis can be carried out under optimized film growth conditions (e.g. at high temperature). Additionally, lifting the need for post-annealing renders this method applicable to heat-sensitive materials and substrates (e.g. films of transparent oxides on polymer substrates). Composition determination across the sample and mapping of physical properties onto the ternary phase diagram is achieved via a simple algorithm using the parameters that describe the deposition-rate profiles. Results are shown for the high-temperature growth of crystalline perovskites (including (Ba,Sr)TiO3 and the formation of a metastable alloy between SrRuO3 and SrSnO3) and the room-temperature growth of transparent conducting oxides.Comment: 6 pages, accepted for publication in Rev. Sci. Inst

    Comparative analysis of ESTs involved in grape responses to Xylella fastidiosa infection

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    BACKGROUND: The gram-negative bacterium Xylella fastidiosa (Xf) is the causal agent of Pierce's disease (PD) in grape as well as diseases of many fruit and ornamental plants. The current molecular breeding efforts have identified genetic basis of PD resistance in grapes. However, the transcriptome level characterization of the host response to this pathogen is lacking. RESULTS: Twelve tissue specific subtractive suppression hybridization (SSH) cDNA libraries derived from a time course sampling scheme were constructed from stems, leaves and shoots of PD resistant and susceptible sibling genotypes (V. rupestris × V. arizonica) in response to Xf infection. A total of 5,794 sequences were obtained from these cDNA libraries from which 993 contigs and 949 singletons were derived. Using Gene Ontology (GO) hierarchy, the non-redundant sequences were classified into the three principal categories: molecular function (30%), cellular components (9%) and biological processes (7%). Comparative analysis found variations in EST expression pattern between infected and non-infected PD resistant and PD susceptible grape genotypes. Among the three tissues, libraries from stem tissues showed significant differences in transcript quality suggesting their important role in grape-Xylella interaction. CONCLUSION: This study constitutes the first attempt to characterize the Vitis differential transcriptome associated with host-pathogen interactions from different explants and genotypes. All the generated ESTs have been submitted to GenBank and are also available through our website for further functional studies

    In silico Proteome-wide Amino aCid and Elemental Composition (PACE) Analysis of Expression Proteomics Data Provides A Fingerprint of Dominant Metabolic Processes

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    AbstractProteome-wide Amino aCid and Elemental composition (PACE) analysis is a novel and informative way of interrogating the proteome. The PACE approach consists of in silico decomposition of proteins detected and quantified in a proteomics experiment into 20 amino acids and five elements (C, H, N, O and S), with protein abundances converted to relative abundances of amino acids and elements. The method is robust and very sensitive; it provides statistically reliable differentiation between very similar proteomes. In addition, PACE provides novel insights into proteome-wide metabolic processes, occurring, e.g., during cell starvation. For instance, both Escherichia coli and Synechocystis down-regulate sulfur-rich proteins upon sulfur deprivation, but E. coli preferentially down-regulates cysteine-rich proteins while Synechocystis mainly down-regulates methionine-rich proteins. Due to its relative simplicity, flexibility, generality and wide applicability, PACE analysis has the potential of becoming a standard analytical tool in proteomics

    Raman investigations of diamond films prepared by combustion flames

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    A detailed Raman analysis has been carried out to establish the mixed nature of carbon bonding in diamond films, deposited at atmospheric pressures in combustion flames. By monitoring the sp3 bonded 1334 cm−1 Raman signature of diamond and sp2 bonded 1350 and 1580 cm−1 signatures of graphite, it has been established that under optimum conditions of flow rates and substrate temperatures, the primary combustion zone provides an ideal situation for diamond growth. The study points out to an a-Si1-xCx like interface (0.5≤x≤1) and an amorphous diamondlike precursor phase. These investigations provide insights into the nature of the diamond films prepared by this technique in establishing their potential in various technological applications

    VitisExpDB: A database resource for grape functional genomics

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    <p>Abstract</p> <p>Background</p> <p>The family Vitaceae consists of many different grape species that grow in a range of climatic conditions. In the past few years, several studies have generated functional genomic information on different <it>Vitis </it>species and cultivars, including the European grape vine, <it>Vitis vinifera</it>. Our goal is to develop a comprehensive web data source for Vitaceae.</p> <p>Description</p> <p>VitisExpDB is an online MySQL-PHP driven relational database that houses annotated EST and gene expression data for <it>V. vinifera </it>and non-<it>vinifera </it>grape species and varieties. Currently, the database stores ~320,000 EST sequences derived from 8 species/hybrids, their annotation (BLAST top match) details and Gene Ontology based structured vocabulary. Putative homologs for each EST in other species and varieties along with information on their percent nucleotide identities, phylogenetic relationship and common primers can be retrieved. The database also includes information on probe sequence and annotation features of the high density 60-mer gene expression chip consisting of ~20,000 non-redundant set of ESTs. Finally, the database includes 14 processed global microarray expression profile sets. Data from 12 of these expression profile sets have been mapped onto metabolic pathways. A user-friendly web interface with multiple search indices and extensively hyperlinked result features that permit efficient data retrieval has been developed. Several online bioinformatics tools that interact with the database along with other sequence analysis tools have been added. In addition, users can submit their ESTs to the database.</p> <p>Conclusion</p> <p>The developed database provides genomic resource to grape community for functional analysis of genes in the collection and for the grape genome annotation and gene function identification. The VitisExpDB database is available through our website <url>http://cropdisease.ars.usda.gov/vitis_at/main-page.htm</url>.</p

    Determination, Development and Validation of Method for Simultaneous AXITINIB Pharmaceutical Dosage form by a Reverse Phase HPLC

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    A simple and selective LC method is described for the determination of AXITINIB dosage forms. Chromatographic separation is observed on a c18 packing column using mobile phase with a mixture of TEA -Acetonitrile (50:50) with detected at 254nm. Linearity was observed in the range 15-45 µg /ml for AXITINIB (r2 =0.997) for drug estimated by the proposed methods was in good agreement with the label claim. The proposed method was validated. The accuracy of the methods was assessed by recovery studies at three different levels. The current study indicated the absence of interference of commonly encountered pharmaceutical additives. The method was precise to be indicated by the repeatability analysis, by showing %RSD > 2. All statistical data proved the validity of the methods and used for routine analysis of pharmaceutical dosage form

    Encryption and Decryption of Images with Pixel Data Modification Using Hand Gesture Passcodes

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    To ensure data security and safeguard sensitive information in society, image encryption and decryption as well as pixel data modifications, are essential. To avoid misuse and preserve trust in our digital environment, it is crucial to use these technologies responsibly and ethically. So, to overcome some of the issues, the authors designed a way to modify pixel data that would hold the hidden information. The objective of this work is to change the pixel values in a way that can be used to store information about black and white image pixel data. Prior to encryption and decryption, by using Python we were able to construct a passcode with hand gestures in the air, then encrypt it without any data loss. It concentrates on keeping track of simply two pixel values. Thus, pixel values are slightly changed to ensure the masked image is not misleading. Considering that the RGB values are at their border values of 254, 255 the test cases of masking overcome issues with the corner values susceptibility
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