216 research outputs found

    Quiet SDS Josephson Junctions for Quantum Computing

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    Unconventional superconductors exhibit an order parameter symmetry lower than the symmetry of the underlying crystal lattice. Recent phase sensitive experiments on YBCO single crystals have established the d-wave nature of the cuprate materials, thus identifying unambiguously the first unconventional superconductor. The sign change in the order parameter can be exploited to construct a new type of s-wave - d-wave - s-wave Josephson junction exhibiting a degenerate ground state and a double-periodic current-phase characteristic. Here we discuss how to make use of these special junction characteristics in the construction of a quantum computer. Combining such junctions together with a usual s-wave link into a SQUID loop we obtain what we call a `quiet' qubit --- a solid state implementation of a quantum bit which remains optimally isolated from its environment.Comment: 4 pages, 2 ps-figure

    Review of parameterisation and a novel database (LiionDB) for continuum Li-ion battery models

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    The Doyle–Fuller–Newman (DFN) framework is the most popular physics-based continuum-level description of the chemical and dynamical internal processes within operating lithium-ion-battery cells. With sufficient flexibility to model a wide range of battery designs and chemistries, the framework provides an effective balance between detail, needed to capture key microscopic mechanisms, and simplicity, needed to solve the governing equations at a relatively modest computational expense. Nevertheless, implementation requires values of numerous model parameters, whose ranges of applicability, estimation, and validation pose challenges. This article provides a critical review of the methods to measure or infer parameters for use within the isothermal DFN framework, discusses their advantages or disadvantages, and clarifies limitations attached to their practical application. Accompanying this discussion we provide a searchable database, available at www.liiondb.com, which aggregates many parameters and state functions for the standard DFN model that have been reported in the literature

    Large introns in relation to alternative splicing and gene evolution: a case study of Drosophila bruno-3

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    Background: Alternative splicing (AS) of maturing mRNA can generate structurally and functionally distinct transcripts from the same gene. Recent bioinformatic analyses of available genome databases inferred a positive correlation between intron length and AS. To study the interplay between intron length and AS empirically and in more detail, we analyzed the diversity of alternatively spliced transcripts (ASTs) in the Drosophila RNA-binding Bruno-3 (Bru-3) gene. This gene was known to encode thirteen exons separated by introns of diverse sizes, ranging from 71 to 41,973 nucleotides in D. melanogaster. Although Bru-3's structure is expected to be conducive to AS, only two ASTs of this gene were previously described. Results: Cloning of RT-PCR products of the entire ORF from four species representing three diverged Drosophila lineages provided an evolutionary perspective, high sensitivity, and long-range contiguity of splice choices currently unattainable by high-throughput methods. Consequently, we identified three new exons, a new exon fragment and thirty-three previously unknown ASTs of Bru-3. All exon-skipping events in the gene were mapped to the exons surrounded by introns of at least 800 nucleotides, whereas exons split by introns of less than 250 nucleotides were always spliced contiguously in mRNA. Cases of exon loss and creation during Bru-3 evolution in Drosophila were also localized within large introns. Notably, we identified a true de novo exon gain: exon 8 was created along the lineage of the obscura group from intronic sequence between cryptic splice sites conserved among all Drosophila species surveyed. Exon 8 was included in mature mRNA by the species representing all the major branches of the obscura group. To our knowledge, the origin of exon 8 is the first documented case of exonization of intronic sequence outside vertebrates. Conclusion: We found that large introns can promote AS via exon-skipping and exon turnover during evolution likely due to frequent errors in their removal from maturing mRNA. Large introns could be a reservoir of genetic diversity, because they have a greater number of mutable sites than short introns. Taken together, gene structure can constrain and/or promote gene evolution

    Novel Modeling of Combinatorial miRNA Targeting Identifies SNP with Potential Role in Bone Density

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    MicroRNAs (miRNAs) are post-transcriptional regulators that bind to their target mRNAs through base complementarity. Predicting miRNA targets is a challenging task and various studies showed that existing algorithms suffer from high number of false predictions and low to moderate overlap in their predictions. Until recently, very few algorithms considered the dynamic nature of the interactions, including the effect of less specific interactions, the miRNA expression level, and the effect of combinatorial miRNA binding. Addressing these issues can result in a more accurate miRNA:mRNA modeling with many applications, including efficient miRNA-related SNP evaluation. We present a novel thermodynamic model based on the Fermi-Dirac equation that incorporates miRNA expression in the prediction of target occupancy and we show that it improves the performance of two popular single miRNA target finders. Modeling combinatorial miRNA targeting is a natural extension of this model. Two other algorithms show improved prediction efficiency when combinatorial binding models were considered. ComiR (Combinatorial miRNA targeting), a novel algorithm we developed, incorporates the improved predictions of the four target finders into a single probabilistic score using ensemble learning. Combining target scores of multiple miRNAs using ComiR improves predictions over the naïve method for target combination. ComiR scoring scheme can be used for identification of SNPs affecting miRNA binding. As proof of principle, ComiR identified rs17737058 as disruptive to the miR-488-5p:NCOA1 interaction, which we confirmed in vitro. We also found rs17737058 to be significantly associated with decreased bone mineral density (BMD) in two independent cohorts indicating that the miR-488-5p/NCOA1 regulatory axis is likely critical in maintaining BMD in women. With increasing availability of comprehensive high-throughput datasets from patients ComiR is expected to become an essential tool for miRNA-related studies. © 2012 Coronnello et al

    Health services performance for TB treatment in Brazil: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Researches to evaluate Primary Health Care performance in TB control in Brazil show that different cities aggregate local specificities in the dynamics of coping with the disease. This study aims to evaluate health services' performance in TB treatment in cities across different Brazilian regions.</p> <p>Methods</p> <p>This cross-sectional study was conducted in five cities that are considered priorities for TB control in Brazil: Itaboraí (ITA), Ribeirão Preto (RP) and São José do Rio Preto (SJRP) in the Southeast; Campina Grande (CG) and Feira de Santana (FS) in the Northeast. Data were collected through interviews with 514 TB patients under treatment in 2007, using the <it>Primary Care Assessment Tool </it>adapted for TB care in Brazil. Indicators were constructed based on the mean response scores (Likert scale) and compared among the study sites.</p> <p>Results</p> <p>"Access to treatment" was evaluated as satisfactory in the Southeast and regular in the Northeast, which displayed poor results on 'home visits' and 'distance between treatment site and patient's house'. "Bond" was assessed as satisfactory in all cities, with a slightly better performance in RP and SJRP. "Range of services" was rated as regular, with better performance of southeastern cities. 'Health education', 'DOT' and 'food vouchers' were less offered in the Northeast. "Coordination" was evaluated as satisfactory in all cities. "Family focus" was evaluated as satisfactory in RP and SJRP, and regular in the others. 'Professional asking patient's family about other health problems' was evaluated as unsatisfactory, except in RP.</p> <p>Conclusions</p> <p>Two types of obstacles are faced for health service performance in TB treatment in the cities under analysis, mainly in the Northeast. The first is structural and derives from difficulties to access health services and actions. The second is organizational and derives from the way health technologies and services are distributed and integrated. Incentives to improve care organization and management practices, aimed at the integration of primary, secondary and tertiary services, can contribute towards a better performance of health services in TB treatment.</p

    Evolutionary distinctiveness of fatty acid and polyketide synthesis in eukaryotes

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    © 2016 International Society for Microbial Ecology All rights reserved. Fatty acids, which are essential cell membrane constituents and fuel storage molecules, are thought to share a common evolutionary origin with polyketide toxins in eukaryotes. While fatty acids are primary metabolic products, polyketide toxins are secondary metabolites that are involved in ecologically relevant processes, such as chemical defence, and produce the adverse effects of harmful algal blooms. Selection pressures on such compounds may be different, resulting in differing evolutionary histories. Surprisingly, some studies of dinoflagellates have suggested that the same enzymes may catalyse these processes. Here we show the presence and evolutionary distinctiveness of genes encoding six key enzymes essential for fatty acid production in 13 eukaryotic lineages for which no previous sequence data were available (alveolates: dinoflagellates, Vitrella, Chromera; stramenopiles: bolidophytes, chrysophytes, pelagophytes, raphidophytes, dictyochophytes, pinguiophytes, xanthophytes; Rhizaria: chlorarachniophytes, haplosporida; euglenids) and 8 other lineages (apicomplexans, bacillariophytes, synurophytes, cryptophytes, haptophytes, chlorophyceans, prasinophytes, trebouxiophytes). The phylogeny of fatty acid synthase genes reflects the evolutionary history of the organism, indicating selection to maintain conserved functionality. In contrast, polyketide synthase gene families are highly expanded in dinoflagellates and haptophytes, suggesting relaxed constraints in their evolutionary history, while completely absent from some protist lineages. This demonstrates a vast potential for the production of bioactive polyketide compounds in some lineages of microbial eukaryotes, indicating that the evolution of these compounds may have played an important role in their ecological success

    Stress System Dynamics during “Life As It Is Lived”: An Integrative Single-Case Study on a Healthy Woman

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    Little is known about the dynamic characteristics of stress system activity during “life as it is lived”. Using as representative a study design as possible, this investigation sought to gain insights into this area. A healthy 25-year-old woman collected her entire urine over a period of 63 days in 12-h intervals (126 measurements) to determine cortisol and neopterin (immune activation marker) levels. In addition, she filled out questionnaires on emotional state and daily routine in 12-h intervals, and was interviewed weekly to identify emotionally negative and positive everyday incidents. Adjusted cross-correlational analyses revealed that stressful incidents were associated with cyclic response patterns in both urinary cortisol and urinary neopterin concentrations. Urinary cortisol levels first decreased 12–24 h after stressful incidents occurred (lag 1: −.178; p = 0.048) and then increased a total of 72–84 h later (lag 6: +.224; p = 0.013). Urinary neopterin levels first increased 0–12 h before the occurrence of stressful incidents (−lag 1: +.185; p = 0.040) and then decreased a total of 48–60 h following such stressors (lag 4: −.181; p = 0.044). Decreases in urinary neopterin levels were also found 24–36 and 48–60 h after increases in pensiveness (lag 2: −.215; p = 0.017) and depressiveness (lag 4: −.221; p = 0.014), respectively. Findings on emotionally positive incidents sharply contrasted with those dealing with negative experiences. Positive incidents were followed first by urinary cortisol concentration increases within 12 h (lag 0: +.290; p = 0.001) and then by decreases after a total of 60–72 h (lag 5: −.186; p = 0.039). Urinary neopterin levels first decreased 12–24 h before positive incidents occurred (−lag 2: −.233; p = 0.010) and then increased a total of 12–24 h following these incidents (lag 1: +.222; p = 0.014). As with previous investigations on patients with systemic lupus erythematosus (SLE), this study showed that stress system response can be considerably longer and more complex and differentiated than findings from conventional group studies have suggested. Further integrative single-case studies will need to be conducted in order to draw firm conclusions about stress system dynamics under real-life conditions
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