696 research outputs found

    Possible realization of Josephson charge qubits in two coupled Bose-Einstein condensates

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    We demonstrate that two coupled Bose-Einstein condensates (BEC) at zero temperature can be used to realize a qubit which is the counterpart of Josephson charge qubits. The two BEC are weakly coupled and confined in an asymmetric double-well trap. When the "charging energy" of the system is much larger than the Josephson energy and the system is biased near a degeneracy point, the two BEC represent a qubit with two states differing only by one atom. The realization of the BEC qubits in realistic BEC experiments is briefly discussed.Comment: 4 pages; comments are welcome / Corrected typos in Eq. (16); a note adde

    DNAzyme Hybridization, Cleavage, Degradation and Sensing in Undiluted Human Blood Serum

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, copyright © American Chemical Society after peer review and technical editing by publisher. To access the final edited and published work see http://dx.doi.org/10.1021/acs.analchem.5b00220.RNA-cleaving DNAzymes provide a unique platform for developing biosensors. However, a majority of the work has been performed in clean buffer solutions, while the activity of some important DNAzymes in biological sample matrices is still under debate. Two RNA-cleaving DNAzymes (17E and 10-23) are the most widely used. In this work, we carefully studied a few key aspects of the 17E DNAzyme in human blood serum, including hybridization, cleavage activity, and degradation kinetics. Since direct fluorescence monitoring is difficult due to the opacity of serum, denaturing and nondenaturing gel electrophoresis were combined for studying the interaction between serum proteins and DNAzymes. The 17E DNAzyme retains its activity in 90% human blood serum with a cleavage rate of 0.04 min–1, which is similar to that in the PBS buffer (0.06 min–1) with a similar ionic strength. The activity in serum can be accelerated to 0.3 min–1 with an additional 10 mM Ca2+. As compared to 17E, the 10-23 DNAzyme produces negligible cleavage in serum. Degradation of both the substrate and the DNAzyme strand is very slow in serum, especially at room temperature. Degradation occurs mainly at the fluorophore label (linked to DNA via an amide bond) instead of the DNA phosphodiester bonds. Serum proteins can bind more tightly to the 17E DNAzyme complex than to the single-stranded substrate or enzyme. The 17E DNAzyme hybridizes extremely fast in serum. With this understanding, the detection of DNA using the 17E DNAzyme is demonstrated in serum.University of Waterloo || Natural Sciences and Engineering Research Council || Foundation for Shenghua Scholar of Central South University|| National Natural Science Foundation of China || Grant No. 21301195 Fellowship from the China Scholarship Council || CSC, Grant No. 20140637011

    Party system closure and openness: conceptualization, operationalization and validation

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    The degree of closure of the governmental arena is a central aspect of the stabilization of party systems, and yet little systematic effort has been devoted to its operationalization. The article proposes a new index, examines its reliability and validity, and reports the ranking of 60 party systems. By redefining the units of measurement we suggest new indicators that are uniform and transparent in their logic of construction, can be applied both to specific government-changes and to time periods, and are sensitive to the degree of change. The article finds a hierarchy among the components of party system closure, dominated by coalition formula. While new and established democracies can both produced closed patterns, the analysis of inter-war European party systems shows that closed systems are less prone to authoritarian takeover. The article demonstrates the power of inertia: the completely closed configurations stand out as the most durable ones

    The Effect of Mindfulness-based Programs on Cognitive Function in Adults: A Systematic Review and Meta-analysis

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    Mindfulness-based programs (MBPs) are increasingly utilized to improve mental health. Interest in the putative effects of MBPs on cognitive function is also growing. This is the first meta-analysis of objective cognitive outcomes across multiple domains from randomized MBP studies of adults. Seven databases were systematically searched to January 2020. Fifty-six unique studies (n = 2,931) were included, of which 45 (n = 2,238) were synthesized using robust variance estimation meta-analysis. Meta-regression and subgroup analyses evaluated moderators. Pooling data across cognitive domains, the summary effect size for all studies favored MBPs over comparators and was small in magnitude (g = 0.15; [0.05, 0.24]). Across subgroup analyses of individual cognitive domains/subdomains, MBPs outperformed comparators for executive function (g = 0.15; [0.02, 0.27]) and working memory outcomes (g = 0.23; [0.11, 0.36]) only. Subgroup analyses identified significant effects for studies of non-clinical samples, as well as for adults aged over 60. Across all studies, MBPs outperformed inactive, but not active comparators. Limitations include the primarily unclear within-study risk of bias (only a minority of studies were considered low risk), and that statistical constraints rendered some p-values unreliable. Together, results partially corroborate the hypothesized link between mindfulness practices and cognitive performance. This review was registered with PROSPERO [CRD42018100904]

    Outcome of Total Parathyroidectomy and Autotransplantation as Treatment of Secondary and Tertiary Hyperparathyroidism in Children and Adults

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    Contains fulltext : 89902.pdf (publisher's version ) (Closed access)BACKGROUND: Treatment safety and effectiveness of total parathyroidectomy and autotransplantation for secondary and tertiary hyperparathyroidism have been extensively proven in adults; the evidence for children, however, is scarce. Children and adolescents cannot simply be seen as young adults in the case of chronic kidney disease and hyperparathyroidism. The aim of this retrospective study was therefore, to evaluate whether parathyroidectomy with forearm autograft is as effective and safe in children and adolescents as in adults. METHODS: A group of 64 adults and 8 children and adolescents treated for secondary or tertiary hyperparathyroidism were retrieved from our database. The outcomes were compared on patient demographics, operation results, and blood parameters consisting of parathyroid hormone (PTH) and calcium levels. Our results were compared with all currently available articles on parathyroidectomy in children with secondary or tertiary hyperparathyroidism (n = 11). RESULTS: For adults, preoperative mean serum calcium was 2.67 +/- 0.29 mmol/l and mean parathyroid hormone (PTH) level was 120 +/- 86 pmol/l. For children, preoperative mean serum calcium was 2.62 +/- 0.20 mmol/l and mean parathyroid hormone (PTH) level was 80 +/- 38 pmol/l. Postoperative calcium and parathyroid hormone levels for adults dropped to 2.39 +/- 0.23 mmol/l and 30 +/- 53 pmol/l, respectively. Postoperative calcium and parathyroid hormone levels for children dropped to 2.41 +/- 0.16 mmol/l and 26 +/- 33 pmol/l, respectively. The effectiveness of parathyroidectomy with autotransplantation was 75% in children and 72% in adults. Thus, effectiveness did not differ significantly between children and adults. CONCLUSIONS: Combining the results of our own study with a literature review on pediatric parathyroidectomy, we conclude that parathyroidectomy and forearm autograft is as effective a treatment for secondary and tertiary hyperparathyroidism in children and adolescents as it is in adults.1 mei 201

    Search for CP Violation in the Decay Z -> b (b bar) g

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    About three million hadronic decays of the Z collected by ALEPH in the years 1991-1994 are used to search for anomalous CP violation beyond the Standard Model in the decay Z -> b \bar{b} g. The study is performed by analyzing angular correlations between the two quarks and the gluon in three-jet events and by measuring the differential two-jet rate. No signal of CP violation is found. For the combinations of anomalous CP violating couplings, h^b=h^AbgVb−h^VbgAb{\hat{h}}_b = {\hat{h}}_{Ab}g_{Vb}-{\hat{h}}_{Vb}g_{Ab} and hb∗=h^Vb2+h^Ab2h^{\ast}_b = \sqrt{\hat{h}_{Vb}^{2}+\hat{h}_{Ab}^{2}}, limits of \hat{h}_b < 0.59and and h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st

    Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years

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    The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deep-water exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of 231Pa and 230Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary 231Pa/230Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured 230Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in 231Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for 231Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export 231Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation

    The estrogen and c-Myc target gene HSPC111 is over-expressed in breast cancer and associated with poor patient outcome

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    Introduction: Estrogens play a pivotal role in the initiation and progression of breast cancer. The genes that mediate these processes are not fully defined, but potentially include the known mammary oncogene MYC. Characterization of estrogen-target genes may help to elucidate further the mechanisms of estrogen-induced mitogenesis and endocrine resistance.Methods: We used a transcript profiling approach to identify targets of estrogen and c-Myc in breast cancer cells. One previously uncharacterized gene, namely HBV pre-S2 trans-regulated protein 3 (HSPC111), was acutely upregulated after estrogen treatment or inducible expression of c-Myc, and was selected for further functional analysis using over-expression and knock-down strategies. HSPC111 expression was also analyzed in relation to MYC expression and outcome in primary breast carcinomas and published gene expression datasets.Results: Pretreatment of cells with c-Myc small interfering RNA abrogated estrogen induction of HSPC111, identifying HSPC111 as a potential c-Myc target gene. This was confirmed by the demonstration of two functional E-box motifs upstream of the transcription start site. HSPC111 mRNA and protein were over-expressed in breast cancer cell lines and primary breast carcinomas, and this was positively correlated with MYC mRNA levels. HSPC111 is present in a large, RNA-dependent nucleolar complex, suggesting a possible role in ribosomal biosynthesis. Neither over-expression or small interfering RNA knock-down of HSPC111 affected cell proliferation rates or sensitivity to estrogen/antiestrogen treatment. However, high expression of HSPC111 mRNA was associated with adverse patient outcome in published gene expression datasets.Conclusion: These data identify HSPC111 as an estrogen and c-Myc target gene that is over-expressed in breast cancer and is associated with an adverse patient outcome
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