323 research outputs found

    Blueprint for a high-performance biomaterial: full-length spider dragline silk genes.

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    Spider dragline (major ampullate) silk outperforms virtually all other natural and manmade materials in terms of tensile strength and toughness. For this reason, the mass-production of artificial spider silks through transgenic technologies has been a major goal of biomimetics research. Although all known arthropod silk proteins are extremely large (>200 kiloDaltons), recombinant spider silks have been designed from short and incomplete cDNAs, the only available sequences. Here we describe the first full-length spider silk gene sequences and their flanking regions. These genes encode the MaSp1 and MaSp2 proteins that compose the black widow's high-performance dragline silk. Each gene includes a single enormous exon (>9000 base pairs) that translates into a highly repetitive polypeptide. Patterns of variation among sequence repeats at the amino acid and nucleotide levels indicate that the interaction of selection, intergenic recombination, and intragenic recombination governs the evolution of these highly unusual, modular proteins. Phylogenetic footprinting revealed putative regulatory elements in non-coding flanking sequences. Conservation of both upstream and downstream flanking sequences was especially striking between the two paralogous black widow major ampullate silk genes. Because these genes are co-expressed within the same silk gland, there may have been selection for similarity in regulatory regions. Our new data provide complete templates for synthesis of recombinant silk proteins that significantly improve the degree to which artificial silks mimic natural spider dragline fibers

    Zirconium Carbide Oxidation and Passivation for Nuclear Fuel Applications

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    Please click Additional Files below to see the full abstract. Please click Download on the upper right corner to see the presentation

    Microwave transmission through a single subwavelength annular aperture in a metal plate

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    Matthew J. Lockyear, Alastair P. Hibbins, J. Roy Sambles, and Christopher R. Lawrence. Physical Review Letters, Vol. 94, article 193902 (2005). "Copyright © 2005 by the American Physical Society."The resonant transmission of a small annular aperture, with a diameter much smaller than the radiation wavelength, in a thin metal plate is studied at microwave frequencies. It transpires that such an annular aperture supports several resonant guided modes, including those that are not quantized in the azimuthal direction. Such modes have resonant frequencies that are largely independent of the diameter of the annular aperture, thus being supported by annular apertures that tend to zero radius. The transmittance of such a structure at microwave frequencies is detailed and compared with the predictions of a finite element method model

    Transcriptional profiling reveals extraordinary diversity among skeletal muscle tissues

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    Skeletal muscle comprises a family of diverse tissues with highly specialized functions. Many acquired diseases, including HIV and COPD, affect specific muscles while sparing others. Even monogenic muscular dystrophies selectively affect certain muscle groups. These observations suggest that factors intrinsic to muscle tissues influence their resistance to disease. Nevertheless, most studies have not addressed transcriptional diversity among skeletal muscles. Here we use RNAseq to profile mRNA expression in skeletal, smooth, and cardiac muscle tissues from mice and rats. Our data set, MuscleDB, reveals extensive transcriptional diversity, with greater than 50% of transcripts differentially expressed among skeletal muscle tissues. We detect mRNA expression of hundreds of putative myokines that may underlie the endocrine functions of skeletal muscle. We identify candidate genes that may drive tissue specialization, including Smarca4, Vegfa, and Myostatin. By demonstrating the intrinsic diversity of skeletal muscles, these data provide a resource for studying the mechanisms of tissue specialization

    One-way diffraction grating

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    Matthew J. Lockyear, Alastair P. Hibbins, Kevin R. White, and J. Roy Sambles, Physical Review E, Vol. 74, article 056611 (2006). "Copyright © 2006 by the American Physical Society."Diffraction gratings are elementary tools for much of optics and spectroscopy. Here, at microwave frequencies, we provide a new perspective on these fundamental structures. A transmission diffraction grating is presented that has diffracted beams emanating from one surface only. It can thus function either as a transmission grating with no reflected orders (other than zero) or, in the reverse configuration, as a partially transmitting structure with diffracted orders in reflection only

    The PyCBC search for gravitational waves from compact binary coalescence

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    We describe the PyCBC search for gravitational waves from compact-object binary coalescences in advanced gravitational-wave detector data. The search was used in the first Advanced LIGO observing run and unambiguously identified two black hole binary mergers, GW150914 and GW151226. At its core, the PyCBC search performs a matched-filter search for binary merger signals using a bank of gravitational-wave template waveforms. We provide a complete description of the search pipeline including the steps used to mitigate the effects of noise transients in the data, identify candidate events and measure their statistical significance. The analysis is able to measure false-alarm rates as low as one per million years, required for confident detection of signals. Using data from initial LIGO's sixth science run, we show that the new analysis reduces the background noise in the search, giving a 30% increase in sensitive volume for binary neutron star systems over previous searches.Comment: 29 pages, 7 figures, accepted by Classical and Quantum Gravit

    Differential MicroRNA Expression Levels in Cutaneous Acute Graft-versus Host Disease

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    Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is a curative treatment for numerous haematological malignancies. However, acute graft-versus-host disease (aGvHD) is a major complication affecting 40-70% of all transplant patients, whereby the earliest and most frequent presentation is in the skin. MicroRNAs play a role in varied biological process and have been reported as potential biomarkers for aGvHD. More recently, microRNAs have received added attention as circulatory biomarkers that can be detected in biofluids. In the present study we performed global microRNA expression profiling using a discovery cohort of diagnostic cutaneous aGvHD biopsies (n=5, stage 1-3) and healthy volunteers (n=4), in order to identify a signature list of microRNAs that could be used as diagnostic biomarkers for cutaneous aGvHD. Candidate microRNAs (n=8) were then further investigated in a validation cohort of post-HSCT skin biopsies (n=17) for their association with aGvHD. Expression of miR-34a-5p (p<0.001), miR-34a-3p (p=0.013), miR-503-5p (p=0.021) and let-7c-5p (p=0.037) was elevated in cutaneous aGvHD and significantly associated with survival outcome (miR-34a-3p ROC AUC=0.93, p=0.003, Log Rank p=0.004; miR-503-5p ROC AUC=0.83 p=0.021, Log Rank p=0.003). There was no association with relapse. A statistical interaction between miR-34a-3p and miR-503-5p (p=0.016) was diagnostic for aGvHD. Expression levels of the miR-34a-5p protein target p53 were assessed in the epidermis of the skin, and an inverse correlation was identified (r2=0.44, p=0.039). Expression of the validated candidate microRNAs was also assessed at day 28 post-HSCT in the sera of transplant recipients, in order to investigate their potential as circulatory microRNA biomarkers. Expression of miR-503-5p (p=0.001), miR-34a-5p (p=0.005) and miR-34a-3p (p=0.004) were significantly elevated in the sera of patients who developed aGvHD vs. no-aGvHD (n=30) and miR-503-5p was associated with overall survival (ROC AUC=0.80, p=0.04, Log Rank p=0.041). In conclusion, this investigation reports that microRNA expression levels in clinical skin biopsies, obtained at the time of cutaneous aGvHD onset, show potential as diagnostic biomarkers for aGvHD and as predictive biomarkers for overall survival. Additionally, the same microRNAs can be detected in the circulation and show predictive association with post-HSCT outcomes

    Conceptual Design of a MEDE Treatment System for Sodium Bonded Fuel

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    Unirradiated sodium bonded metal fuel and casting scrap material containing highly enriched uranium (HEU) is stored at the Materials and Fuels Complex (MFC) on the Idaho National Laboratory (INL). This material, which includes intact fuel assemblies and elements from the Fast Flux Test Facility (FFTF) and Experimental Breeder Reactor-II (EBR-II) reactors as well as scrap material from the casting of these fuels, has no current use under the terminated reactor programs for both facilities. The Department of Energy (DOE), under the Sodium-Bonded Spent Nuclear Fuel Treatment Record of Decision (ROD), has determined that this material could be prepared and transferred to an off-site facility for processing and eventual fabrication of fuel for commercial nuclear reactors. A plan is being developed to prepare, package and transfer this material to the DOE High Enriched Uranium Disposition Program Office (HDPO), located at the Y-12 National Security Complex in Oak Ridge, Tennessee. Disposition of the sodium bonded material will require separating the elemental sodium from the metallic uranium fuel. A sodium distillation process known as MEDE (Melt-Drain-Evaporate), will be used for the separation process. The casting scrap material needs to be sorted to remove any foreign material or fines that are not acceptable to the HDPO program. Once all elements have been cut and loaded into baskets, they are then loaded into an evaporation chamber as the first step in the MEDE process. The chamber will be sealed and the pressure reduced to approximately 200 mtorr. The chamber will then be heated as high as 650 ºC, causing the sodium to melt and then vaporize. The vapor phase sodium will be driven into an outlet line where it is condensed and drained into a receiver vessel. Once the evaporation operation is complete, the system is de-energized and returned to atmospheric pressure. This paper describes the MEDE process as well as a general overview of the furnace systems, as necessary, to complete the MEDE process

    PENGARUH ATOPI TERHADAP TIMBULNYA DERMATITIS KONTAK PADA MAHASISWIRNPENDIDIKAN DOKTER FAKULTAS KEDOKTERAN UNIVERSITAS SYIAH KUALA RNBANDA ACEH

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    Dermatitis kontak adalah inflamasi non infeksi pada kulit yang disebabkan karena pemaparan dengan suatu zat tertentu yang dapat mengiritasi kulit atau menyebabkan reaksi alergi. Perempuan lebih sering mengalami dermatitis kontak dibandingkan laki-laki. Atopi merupakan salah satu faktor predisposisi timbulnya dermatitis kontak. Penelitian ini bertujuan untuk mengetahui pengaruh atopi terhadap timbulnya dermatitis kontak pada mahasiswi Pendidikan Dokter Fakultas Kedokteran Universitas Syiah Kuala Banda Aceh. Penelitian ini bersifat analitik dengan pendekatan cross sectional. Data yang digunakan adalah data primer yang diperoleh dengan wawancara langsung pada responden. Uji statistik dengan menggunakan Chi Square diperoleh nilai p yang signifikan sebesar 0,00, ini berarti p < 0,05 maka secara statistik didapatkan hubungan antara atopi dengan dermatitis kontak dengan rasio prevalensi 2,17, artinya seseorang yang menderita atopi memiliki peluang sebesar 2,17 kali untuk mengalami dermatitis kontak dibandingkan dengan orang yang tidak menderita atopi. Bahan yang paling sering menyebabkan dermatitis kontak pada mahasiswi adalah deterjen dan kosmetik. Hasil penelitian yang diperoleh ada pengaruh atopi terhadap timbulnya dermatitis kontak pada mahasiswi Pendidikan Dokter FK Unsyiah Banda Aceh, dimana mahasiswi yang menderita atopi cenderung mengalami dermatitis kontak.Kata kunci: Atopi, Dermatitis kontak Alergi, Dermatitis kontak iritanBanda Ace

    Detecting autozygosity through runs of homozygosity: A comparison of three autozygosity detection algorithms

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    <p>Abstract</p> <p>Background</p> <p>A central aim for studying runs of homozygosity (ROHs) in genome-wide SNP data is to detect the effects of autozygosity (stretches of the two homologous chromosomes within the same individual that are identical by descent) on phenotypes. However, it is unknown which current ROH detection program, and which set of parameters within a given program, is optimal for differentiating ROHs that are truly autozygous from ROHs that are homozygous at the marker level but vary at unmeasured variants between the markers.</p> <p>Method</p> <p>We simulated 120 Mb of sequence data in order to know the true state of autozygosity. We then extracted common variants from this sequence to mimic the properties of SNP platforms and performed ROH analyses using three popular ROH detection programs, PLINK, GERMLINE, and BEAGLE. We varied detection thresholds for each program (e.g., prior probabilities, lengths of ROHs) to understand their effects on detecting known autozygosity.</p> <p>Results</p> <p>Within the optimal thresholds for each program, PLINK outperformed GERMLINE and BEAGLE in detecting autozygosity from distant common ancestors. PLINK's sliding window algorithm worked best when using SNP data pruned for linkage disequilibrium (LD).</p> <p>Conclusion</p> <p>Our results provide both general and specific recommendations for maximizing autozygosity detection in genome-wide SNP data, and should apply equally well to research on whole-genome autozygosity burden or to research on whether specific autozygous regions are predictive using association mapping methods.</p
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