4,470 research outputs found

    Some additional properties of elementary landscapes

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    AbstractIn this work, we derive a general class of multistep composite elementary landscapes and present the first non-trivial lower (upper) bounds on local minima (maxima) associated with elementary landscapes

    Inversionless gain in a three-level system driven by a strong field and collisions

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    Inversionless gain in a three-level system driven by a strong external field and by collisions with a buffer gas is investigated. The mechanism of populating of the upper laser level contributed by the collision transfer as well as by relaxation caused by a buffer gas is discussed in detail. Explicit formulae for analysis of optimal conditions are derived. The mechanism developed here for the incoherent pump could be generalized to other systems.Comment: RevTeX, 9 pages, 4 eps figure

    Optical spectra, crystal-field parameters, and magnetic susceptibility of the new multiferroic NdFe3(BO3)4

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    We report high-resolution optical absorption spectra for NdFe3(BO3)4 trigonal single crystal which is known to exhibit a giant magnetoelectric effect below the temperature of magnetic ordering TN = 33 K. The analysis of the temperature-dependent polarized spectra reveals the energies and, in some cases, symmetries and exchange splittings of Nd3+ 84 Kramers doublets. We perform crystal-field calculations starting from the exchange-charge model, obtain a set of six real crystal-field parameters, and calculate wave functions and magnetic g-factors. In particular, the values g(perpendicular) = 2.385, g(parallel) = 1.376 were found for the Nd3+ ground-state doublet. We obtain Bloc=7.88 T and |JFN|= 0.48 K for the values of the local effective magnetic field at liquid helium temperatures at the Nd3+ site and the Nd - Fe exchange integral, respectively, using the experimentally measured Nd3+ ground-state splitting of 8.8 cm-1. To check reliability of our set of crystal field parameters we model the magnetic susceptibility data from literature. A dimer containing two nearest-neighbor iron ions in the spiral chain is considered to partly account for quasi-one-dimensional properties of iron borates, and then the mean-field approximation is used. The results of calculations with the exchange parameters for Fe3+ ions Jnn = -6.25 K (intra-chain interactions) and Jnnn = -1.92 K (inter-chain interactions) obtained from fitting agree well with the experimental data.Comment: 13 pages, 8 figures, 2 table

    Status of social competencies of power engineers in the context of forming the concept of an intelligent network or smart grid

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    The article reviews the trends which define development of power engineering in the world and in Russia. The authors emphasize that establishment of smart grids is the consequence of not only technological but also social transformations of a modern society. The authors sum up that social competencies are an integral part of professional skills of engineers who work in the field of power engineering. The authors make a hypothesis that the major (educational module) “Energy consultant for the population” might develop social competencies

    Effect of transient pinning on stability of drops sitting on an inclined plane

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    We report on new instabilities of the quasi-static equilibrium of water drops pinned by a hydrophobic inclined substrate. The contact line of a statically pinned drop exhibits three transitions of partial depinning: depinning of the advancing and receding parts of the contact line and depinning of the entire contact line leading to the drop's translational motion. We find a region of parameters where the classical Macdougall-Ockrent-Frenkel approach fails to estimate the critical volume of the statically pinned inclined drop

    Maximum tumor diameter is associated with event-free survival in PET-negative patients with stage I/IIA Hodgkin lymphoma.

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    Introduction: the high cure rates achieved in early-stage (ES) Hodgkin lymphoma (HL) are one of the great successes of hemato-oncology, but late treatment-related toxicity undermines long-term survival. Improving overall survival and quality of life further will require maintaining disease control while potentially de-escalating chemotherapy and/or omitting radiotherapy to reduce late toxicity. Accurate stratification of patients is required to facilitate individualized treatment approaches. Response assessment using 18F-fluorodeoxyglucose positron emission tomography (PET) is a powerful predictor of outcome in HL,1,2 and has been used in multiple studies, including the United Kingdom National Cancer Research Institute Randomised Phase III Trial to Determine the Role of FDG–PET Imaging in Clinical Stages IA/IIA Hodgkin’s Disease (UK NCRI RAPID) trial, to investigate whether patients achieving complete metabolic remission (CMR) can be treated with chemotherapy alone.3-5 These PET-adapted trials have demonstrated that omitting radiotherapy results in higher relapse rates, but without compromising overall survival.3-5 For the 75% of patients who achieved CMR in RAPID, neither baseline clinical risk stratification (favorable/unfavorable) nor PET (Deauville score 1/2) predicted disease relapse; additional biomarkers are needed.1 Tumor bulk has long been recognized as prognostic in HL,1,6 but there remains uncertainty about the significance and definition of bulk in the era of PET-adapted treatment.7 We performed a subsidiary analysis of RAPID to assess the prognostic value of baseline maximum tumor dimension (MTD) in patients achieving CMR. Methods: ee have previously reported the RAPID trial design, primary results, and outcomes according to pretreatment risk stratification and PET score.1,3 Patients were aged 16 to 75 years with untreated ES-HL and without B-symptoms or mediastinal bulk (mass > 1/3 internal mediastinal diameter at T5/6).6 Metabolic response after 3 cycles of ABVD chemotherapy (doxorubicin, bleomycin, vinblastine, and dacarbazine) was centrally assessed using PET (N = 562). Patients with CMR (ie, Deauville score 1-2) were randomly assigned to receive involved field radiotherapy (IFRT; n = 208) or no further therapy (NFT; n = 211). PET-positive patients (score, 3-5; n = 143) received a fourth cycle of ABVD and IFRT. Baseline disease assessment was performed by computed tomography, and bidimensional target lesion measurements were reported by local radiologists in millimeters. The association of baseline MTD with HL-related event-free survival (EFS: progression or HL-related death) and progression-free survival (PFS) (progression or any-cause death) was assessed using Kaplan-Meier and Cox regression analyses. Non-HL deaths were either related to primary treatment toxicity or occurred in HL remission.1 United Kingdom ethical approval for the RAPID trial was via the UK Multicentre Research ethics committee. Results and discussion: baseline patient characteristics have been previously described.1 Median age was 34 years (range, 16-75 years); 184 (37.4%) of 492 patients had unfavorable risk by European Organisation for Research and Treatment of Cancer criteria, and 155 (32.3%) of 480 by German Hodgkin Study Groupcriteria. Median MTD for patients achieving CMR was 3.0 cm (interquartile range, 2.0-4.0 cm) and 3.0 cm (interquartile range, 1.8-4.5 cm) in the NFT and IFRT groups, respectively, whereas PET-positive patients had a median MTD of 3.9 cm (interquartile range, 2.8-5.1 cm). After a median follow-up of 61.6 m, 44 HL progression events occurred: 21 NFT, 9 IFRT and 14 PET-positive. No patient received salvage treatment without documented progression. Only 5 HL-related deaths occurred (1 IFRT, 4 PET-positive), and 12 non-HL deaths (4 NFT, 6 IFRT, 2 PET-positive).1 For patients with CMR (N = 419), there was a strong association between MTD and EFS (hazard ratio [HR], 1.19; 95% confidence interval [CI], 1.02-1.39; P = .02), adjusting for treatment group, with an approximate 19% increase in HL risk per centimeter increase in MTD. The association was similar in both treatment groups (NFT HR, 1.20 [95% CI, 0.99-1.44; P = .06]; IFRT HR, 1.19 [95% CI, 0.92-1.55; P = .19]). The observed effect sizes did not markedly change after adjusting for baseline clinical risk factors, and similar results were observed for PFS (supplemental Table 1). In contrast, for PET-positive patients, there was no association between MTD and EFS (HR, 0.88; 95% CI, 0.70-1.11; P = .29) or PFS (HR, 0.87; 95% CI, 0.70-1.08; P = .21). In an exploratory analysis within the NFT group, MTD was dichotomized using increasing 1-cm intervals to investigate the relationship between MTD thresholds and EFS. The largest effect size was observed with an MTD threshold of ≥5 cm (Table 1). Similar results were observed for PFS; this threshold also performed best in time-dependent receiver operating characteristic curve analyses. It was not possible to assess MTD thresholds in the IFRT group with only 9 events. Among all randomized patients, 79 (18.9%) had MTD of ≥5 cm, the majority with mediastinal (n = 43), supraclavicular (n = 17), or cervical (n = 16) locations. Five-year EFS for patients with MTD of ≥5 cm randomly assigned to NFT and IFRT was 79.3% (n = 39; 95% CI, 66.6%-92.0%) and 94.9% (n = 40; 95% CI, 88.0%-100%), respectively (P = .03; Figure 1)

    Ovalbumin sensitization and challenge increases the number of lung cells possessing a mesenchymal stromal cell phenotype

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    Abstract Background Recent studies have indicated the presence of multipotent mesenchymal stromal cells (MSCs) in human lung diseases. Excess airway smooth muscle, myofibroblasts and activated fibroblasts have each been noted in asthma, suggesting that mesenchymal progenitor cells play a role in asthma pathogenesis. We therefore sought to determine whether MSCs are present in the lungs of ovalbumin (OVA)-sensitized and challenged mice, a model of allergic airways disease. Methods Balb/c mice were sensitized and challenged with PBS or OVA over a 25 day period. Flow cytometry as well as colony forming and differentiation potential were used to analyze the emergence of MSCs along with gene expression studies using immunochemical analyses, quantitative polymerase chain reaction (qPCR), and gene expression beadchips. Results A CD45-negative subset of cells expressed Stro-1, Sca-1, CD73 and CD105. Selection for these markers and negative selection against CD45 yielded a population of cells capable of adipogenic, osteogenic and chondrogenic differentiation. Lungs from OVA-treated mice demonstrated a greater average colony forming unit-fibroblast (CFU-F) than control mice. Sorted cells differed from unsorted lung adherent cells, exhibiting a pattern of gene expression nearly identical to bone marrow-derived sorted cells. Finally, cells isolated from the bronchoalveolar lavage of a human asthma patient showed identical patterns of cell surface markers and differentiation potential. Conclusions In summary, allergen sensitization and challenge is accompanied by an increase of MSCs resident in the lungs that may regulate inflammatory and fibrotic responses.http://deepblue.lib.umich.edu/bitstream/2027.42/78265/1/1465-9921-11-127.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78265/2/1465-9921-11-127.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78265/3/1465-9921-11-127-S1.DOCPeer Reviewe
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