674 research outputs found

    An all silicon quantum computer

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    A solid-state implementation of a quantum computer composed entirely of silicon is proposed. Qubits are Si-29 nuclear spins arranged as chains in a Si-28 (spin-0) matrix with Larmor frequencies separated by a large magnetic field gradient. No impurity dopants or electrical contacts are needed. Initialization is accomplished by optical pumping, algorithmic cooling, and pseudo-pure state techniques. Magnetic resonance force microscopy is used for readout. This proposal takes advantage of many of the successful aspects of solution NMR quantum computation, including ensemble measurement, RF control, and long decoherence times, but it allows for more qubits and improved initialization.Comment: ReVTeX 4, 5 pages, 2 figure

    PHIP - a novel candidate breast cancer susceptibility locus on 6q14.1

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    Most non-BRCA1/2 breast cancer families have no identified genetic cause. We used linkage and haplotype analyses in familial and sporadic breast cancer cases to identify a susceptibility locus on chromosome 6q. Two independent genome-wide linkage analysis studies suggested a 3 Mb locus on chromosome 6q and two unrelated Swedish families with a LOD > 2 together seemed to share a haplotype in 6q14.1. We hypothesized that this region harbored a rare high-risk founder allele contributing to breast cancer in these two families. Sequencing of DNA and RNA from the two families did not detect any pathogenic mutations. Finally, 29 SNPs in the region were analyzed in 44,214 cases and 43,532 controls from BCAC, and the original haplotypes in the two families were suggested as low-risk alleles for European and Swedish women specifically. There was also some support for one additional independent moderate-risk allele in Swedish familial samples. The results were consistent with our previous findings in familial breast cancer and supported a breast cancer susceptibility locus at 6q14.1 around the PHIP gene.Peer reviewe

    Gracilaria parva sp. nov. (Gracilariales, Rhodophyta) a Diminutive Species from the Tropical Eastern Pacific

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    DNA sequencing of the plastid encoded rbcL gene supported by morpho-anatomical features reveals Gracilaria parva sp. nov. from Panama and Ecuador in the tropical eastern Pacific Ocean. In the rbcL phylogram, G. parva occurs in a clade sister to the western Atlantic species G. galatensis. Morphologically and anatomically, G. parva is distinguished from two similar, described tropical eastern Pacific species, G. brevis and G. veleroae by its small size, to 2.5 cm tall with branch widths mostly <2 mm occasionally to 4 mm, and by its two to three cell layered cortex. Gracilaria brevis and G. veleroae are taller, have wider branches, and a one cell layered cortex. DNA sequencing is needed to resolve the many diminutive species in the tropical eastern Pacific, particularly those occurring in turf communities. DNA sequencing of historical type specimens from the 19th and 20th centuries is also needed to correctly apply names in this region

    Altered Tyrosine Phosphorylation of Cardiac Proteins Prompts Contractile Dysfunction in Hypertrophic Cardiomyopathy

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    Altered Serine/Threonine phosphorylation of the cardiac proteome is an established hallmark of heart failure (HF). However, the contribution of tyrosine phosphorylation to the pathogenesis of these diseases remains unclear. The cardiac proteome was explored by global mapping to discover and quantify site-specific tyrosine phosphorylation in two cardiac hypertrophic models; cardiac overexpression of ErbB2 (TgErbB2) and cardiac expression of a-Myosin heavy chain R403Q (R403Q-aMyHCTg) compared to control hearts. Phosphoproteomic changes found in R403Q-aMyHC Tg mice indicated EGFR1, Focal Adhesion, VEGF, ErbB signaling, and Chemokine signaling pathways activity were likely to be activated. On the other hand, TgErbB2 mice findings displayed significant overrepresentation of Right Ventricular Cardiomyopathy, Hypertrophic Cardiomyopathy (HCM), and dilated cardiomyopathy (DCM) KEGG Pathways. In silico kinase-substrate enrichment analysis (KSEA) highlighted a marked downregulation of canonical MAPK Pathway Activity downstream of k-Ras in TgErbB2 mice and activation of EGFR, PP2 inhibition of c-Src, and Hepatocyte growth factor stimulation. In vivo ErbB2 inhibition by AG-825 decreased cardiac fibrosis, cardiomyocyte disarray, and rescued contractile function on TgErbB2 mice. These results suggest that altered tyrosine phosphorylation may play a regulatory role in cardiac hypertrophic models, suggesting that tyrosine kinase inhibitors could be used therapeutically in Hypertrophic Cardiomyopathy

    On the analysis of sedimentation velocity in the study of protein complexes

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    Sedimentation velocity analytical ultracentrifugation has experienced a significant transformation, precipitated by the possibility of efficiently fitting Lamm equation solutions to the experimental data. The precision of this approach depends on the ability to account for the imperfections of the experiment, both regarding the sample and the instrument. In the present work, we explore in more detail the relationship between the sedimentation process, its detection, and the model used in the mathematical data analysis. We focus on configurations that produce steep and fast-moving sedimentation boundaries, such as frequently encountered when studying large multi-protein complexes. First, as a computational tool facilitating the analysis of heterogeneous samples, we introduce the strategy of partial boundary modeling. It can simplify the modeling by restricting the direct boundary analysis to species with sedimentation coefficients in a predefined range. Next, we examine factors related to the experimental detection, including the magnitude of optical aberrations generated by out-of-focus solution columns at high protein concentrations, the relationship between the experimentally recorded signature of the meniscus and the meniscus parameter in the data analysis, and the consequences of the limited radial and temporal resolution of the absorbance optical scanning system. Surprisingly, we find that large errors can be caused by the finite scanning speed of the commercial absorbance optics, exceeding the statistical errors in the measured sedimentation coefficients by more than an order of magnitude. We describe how these effects can be computationally accounted for in SEDFIT and SEDPHAT

    Case 2--1994 management of a cardiac pheochromocytoma in two patients

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31664/1/0000599.pd

    DNA methylation markers predict recurrence-free interval in triple-negative breast cancer

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    We lack tools to risk-stratify triple-negative breast cancer (TNBC). Our goal was to develop molecular tools to predict disease recurrence. Methylation array analysis was performed on 110 samples treated by locoregional therapy obtained from institutional cohorts. Discovered marker sets were then tested by Kaplan−Meier analyses in a prospectively collected TNBC cohort of 49 samples from the no-chemotherapy arms of IBCSG trials VIII and IX, and by logistic regression in a chemotherapy-treated cohort of 121 TNBCs from combined IBCSG trials and institutional repositories. High methylation was associated with shorter recurrence-free interval in the no-chemotherapy arm of the IBCSG studies, as well as in the chemotherapy-treated patients within the combined institutional and IBCSG chemotherapy cohorts (100 marker panel, p = 0.002; 30 marker panel, p = 0.05). Chromosome 19 sites were enriched among these loci. In conclusion, our hypermethylation signatures identify increased recurrence risk independent of whether patients receive chemotherapy
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