1,309 research outputs found

    Automating Tolerance Synthesis: A Framework and Tools

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    This paper describes CASCADE-T—a new approach to tolerance synthesis that uses a complete representation of the conditional tolerance relations that exist between features of a part under design. Conditional tolerances are automatically determined from functional requirements and shape information. Tolerance primitives based on the virtual boundary requirements approach to tolerance representation are composed to form more complex tolerance relationships. Artificial intelligence techniques, including a constraint network, frame-based system, and dependency tracking are used to support flexible and detailed computation for tolerance analysis and synthesis

    The Unique Origin of Colors of Armchair Carbon Nanotubes

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    The colors of suspended metallic colloidal particles are determined by their size-dependent plasma resonance, while those of semiconducting colloidal particles are determined by their size-dependent band gap. Here, we present a novel case for armchair carbon nanotubes, suspended in aqueous medium, for which the color depends on their size-dependent excitonic resonance, even though the individual particles are metallic. We observe distinct colors of a series of armchair-enriched nanotube suspensions, highlighting the unique coloration mechanism of these one-dimensional metals.Comment: 4 pages, 3 figure

    An RxLR effector from phytophthora infestans prevents re-localisation of two plant NAC transcription factors from the endoplasmic reticulum to the nucleus

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    The plant immune system is activated following the perception of exposed, essential and invariant microbial molecules that are recognised as non-self. A major component of plant immunity is the transcriptional induction of genes involved in a wide array of defence responses. In turn, adapted pathogens deliver effector proteins that act either inside or outside plant cells to manipulate host processes, often through their direct action on plant protein targets. To date, few effectors have been shown to directly manipulate transcriptional regulators of plant defence. Moreover, little is known generally about the modes of action of effectors from filamentous (fungal and oomycete) plant pathogens. We describe an effector, called Pi03192, from the late blight pathogen Phytophthora infestans, which interacts with a pair of host transcription factors at the endoplasmic reticulum (ER) inside plant cells. We show that these transcription factors are released from the ER to enter the nucleus, following pathogen perception, and are important in restricting disease. Pi03192 prevents the plant transcription factors from accumulating in the host nucleus, revealing a novel means of enhancing host susceptibility

    Metal-Insulator Transitions in Degenerate Hubbard Models and Ax_xC60_{60}

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    Mott-Hubbard metal-insulator transitions in NN-fold degenerate Hubbard models are studied within the Gutzwiller approximation. For any rational filling with xx (integer) electrons per site it is found that metal-insulator transition occurs at a critical correlation energy Uc(N,x)=Uc(N,2N−x)=γ(N,x)∣ϵˉ(N,x)∣U_c(N,x)=U_c(N,2N-x)=\gamma(N,x)|\bar{\epsilon}(N,x)|, where ϵˉ\bar{\epsilon} is the band energy per particle for the uncorrelated Fermi-liquid state and γ(N,x)\gamma(N,x) is a geometric factor which increases linearly with xx. We propose that the alkali metal doped fullerides AxC60A_xC_{60} can be described by a 3-fold degenerate Hubbard model. Using the current estimate of band width and correlation energy this implies that most of AxC60{\rm A_xC_{60}}, at integer xx, are Mott-Hubbard insulators and A3C60{\rm A_3C_{60}} is a strongly correlated metal.Comment: 10 pages, Revte

    The association of cold weather and all-cause and cause-specific mortality in the island of Ireland between 1984 and 2007

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article has been made available through the Brunel Open Access Publishing Fund.Background This study aimed to assess the relationship between cold temperature and daily mortality in the Republic of Ireland (ROI) and Northern Ireland (NI), and to explore any differences in the population responses between the two jurisdictions. Methods A time-stratified case-crossover approach was used to examine this relationship in two adult national populations, between 1984 and 2007. Daily mortality risk was examined in association with exposure to daily maximum temperatures on the same day and up to 6 weeks preceding death, during the winter (December-February) and cold period (October-March), using distributed lag models. Model stratification by age and gender assessed for modification of the cold weather-mortality relationship. Results In the ROI, the impact of cold weather in winter persisted up to 35 days, with a cumulative mortality increase for all-causes of 6.4% (95%CI=4.8%-7.9%) in relation to every 1oC drop in daily maximum temperature, similar increases for cardiovascular disease (CVD) and stroke, and twice as much for respiratory causes. In NI, these associations were less pronounced for CVD causes, and overall extended up to 28 days. Effects of cold weather on mortality increased with age in both jurisdictions, and some suggestive gender differences were observed. Conclusions The study findings indicated strong cold weather-mortality associations in the island of Ireland; these effects were less persistent, and for CVD mortality, smaller in NI than in the ROI. Together with suggestive differences in associations by age and gender between the two Irish jurisdictions, the findings suggest potential contribution of underlying societal differences, and require further exploration. The evidence provided here will hope to contribute to the current efforts to modify fuel policy and reduce winter mortality in Ireland

    Alteration of the bZIP60/IRE1 Pathway Affects Plant Response to ER Stress in Arabidopsis thaliana

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    The Unfolded Protein Response (UPR) is elicited under cellular and environmental stress conditions that disrupt protein folding in the endoplasmic reticulum (ER). Through the transcriptional induction of genes encoding ER resident chaperones and proteins involved in folding, the pathway contributes to alleviating ER stress by increasing the folding capacity in the ER. Similarly to other eukaryotic systems, one arm of the UPR in Arabidopsis is set off by a non-conventional splicing event mediated by ribonuclease kinase IRE1b. The enzyme specifically targets mature bZIP60 RNA for cleavage, which results in a novel splice variant encoding a nuclear localized transcription factor. Although it is clear that this molecular switch widely affects the transcriptome, its exact role in overall plant response to stress has not been established and mutant approaches have not provided much insight. In this study, we took a transgenic approach to manipulate the pathway in positive and negative fashions. Our data show that the ER-resident chaperone BiP accumulates differentially depending on the level of activation of the pathway. In addition, phenotypes of the transgenic lines suggest that BiP accumulation is positively correlated with plant tolerance to chronic ER stress

    Moon Shadow by Cosmic Rays under the Influence of Geomagnetic Field and Search for Antiprotons at Multi-TeV Energies

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    We have observed the shadowing of galactic cosmic ray flux in the direction of the moon, the so-called moon shadow, using the Tibet-III air shower array operating at Yangbajing (4300 m a.s.l.) in Tibet since 1999. Almost all cosmic rays are positively charged; for that reason, they are bent by the geomagnetic field, thereby shifting the moon shadow westward. The cosmic rays will also produce an additional shadow in the eastward direction of the moon if cosmic rays contain negatively charged particles, such as antiprotons, with some fraction. We selected 1.5 x10^{10} air shower events with energy beyond about 3 TeV from the dataset observed by the Tibet-III air shower array and detected the moon shadow at ∼40σ\sim 40 \sigma level. The center of the moon was detected in the direction away from the apparent center of the moon by 0.23∘^\circ to the west. Based on these data and a full Monte Carlo simulation, we searched for the existence of the shadow produced by antiprotons at the multi-TeV energy region. No evidence of the existence of antiprotons was found in this energy region. We obtained the 90% confidence level upper limit of the flux ratio of antiprotons to protons as 7% at multi-TeV energies.Comment: 13pages,4figures; Accepted for publication in Astroparticle Physic

    Cancer and psychiatric diagnoses in the year preceding suicide

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    BACKGROUND: Patients with cancer are known to be at increased risk for suicide but little is known about the interaction between cancer and psychiatric diagnoses, another well-documented risk factor. METHODS: Electronic medical records from nine healthcare systems participating in the Mental Health Research Network were aggregated to form a retrospective case-control study, with ICD-9 codes used to identify diagnoses in the 1 year prior to death by suicide for cases (N = 3330) or matching index date for controls (N = 297,034). Conditional logistic regression was used to assess differences in cancer and psychiatric diagnoses between cases and controls, controlling for sex and age. RESULTS: Among patients without concurrent psychiatric diagnoses, cancer at disease sites with lower average 5-year survival rates were associated with significantly greater relative risk, while cancer disease sites with survival rates of \u3e70% conferred no increased risk. Patients with most psychiatric diagnoses were at higher risk, however, there was no additional risk conferred to these patients by a concurrent cancer diagnosis. CONCLUSION: We found no evidence of a synergistic effect between cancer and psychiatric diagnoses. However, cancer patients with a concurrent psychiatric illness remain at the highest relative risk for suicide, regardless of cancer disease site, due to strong independent associations between psychiatric diagnoses and suicide. For patients without a concurrent psychiatric illness, cancer disease sites associated with worse prognoses appeared to confer greater suicide risk

    Preliminary results of trial NPC-0501 evaluating the therapeutic gain by changing from concurrent-adjuvant to induction-concurrent chemoradiotherapy, changing from fluorouracil to capecitabine, and changing from conventional to accelerated radiotherapy fractionation in patients with locoregionally advanced nasopharyngeal carcinoma

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    © 2014 American Cancer Society. BACKGROUND A current recommendation for locoregionally advanced nasopharyngeal carcinoma (NPC) is conventional fractionated radiotherapy with concurrent cisplatin plus adjuvant cisplatin and fluorouracil (PF). In this randomized trial, the authors evaluated the potential therapeutic benefit from changing to an induction-concurrent chemotherapy sequence, replacing fluorouracil with oral capecitabine, and/or using accelerated rather than conventional radiotherapy fractionation. METHODS Patients with stage III through IVB, nonkeratinizing NPC were randomly allocated to 1 of 6 treatment arms. The protocol was amended in 2009 to permit confining randomization to the conventional fractionation arms. The primary endpoint was progression-free survival. Secondary endpoints included overall survival and safety. RESULTS In total, 803 patients were accrued, and 706 patients were randomly allocated to all 6 treatment arms. Comparisons of induction PF versus adjuvant PF did not indicate a significant improvement. Unadjusted comparisons of induction cisplatin and capecitabine (PX) versus adjuvant PF indicated a favorable trend in progression-free survival for the conventional fractionation arm (P = .045); analyses that were adjusted for other significant factors and fractionation reflected a significant reduction in the hazards of disease progression (hazard ratio [HR], 0.54; 95% confidence interval [CI], 0.36-0.80) and death (HR, 0.42; 95% CI, 0.25-0.70). Unadjusted comparisons of induction sequences versus adjuvant sequences did not reach statistical significance, but adjusted comparisons indicated favorable improvements by induction sequence. Comparisons of induction PX versus induction PF revealed fewer toxicities (neutropenia and electrolyte disturbance), unadjusted comparisons of efficacy were statistically insignificant, but adjusted analyses indicated that induction PX had a lower hazard of death (HR, 0.57; 95% CI, 0.34-0.97). Changing the fractionation from conventional to accelerated did not achieve any benefit but incurred higher toxicities (acute mucositis and dehydration). CONCLUSIONS Preliminary results indicate that the benefit of changing to an induction-concurrent sequence remains uncertain; replacing fluorouracil with oral capecitabine warrants further validation in view of its convenience, favorable toxicity profile, and favorable trends in efficacy; and accelerated fractionation is not recommended for patients with locoregionally advanced NPC who receive chemoradiotherapy.postprin
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