99 research outputs found
Supramolecular Complexes from CdSe Nanocrystals and Organic Fluorophors
Heterosupramolecular structures from CdSe or CdSe/ZnS core/shell nanocrystals and a specially designed organic fluorophore (diazaperylene) have been prepared to investigate the electronic interactions at nanoscopic semiconductor surfaces. To determine the average number of dye molecules per nanocrystal, we monitored the size-dependent molar extinction coefficient of CdSe particles. The NC/dye ratio is depending on the particle size and varies between 3 and 20 dye molecules per nanocrystal. We demonstrate that the fluorescence of the nanocrystals is completely quenched upon the formation of the supramolecular NC/dye complex even if the surface of the CdSe particles is covered with a few monolayers of the high band gap semiconductor ZnS
The role of regulatory T cells in antigen-induced arthritis: aggravation of arthritis after depletion and amelioration after transfer of CD4(+)CD25(+ )T cells
It is now generally accepted that CD4(+)CD25(+ )T(reg )cells play a major role in the prevention of autoimmunity and pathological immune responses. Their involvement in the pathogenesis of chronic arthritis is controversial, however, and so we examined their role in experimental antigen-induced arthritis in mice. Depletion of CD25-expressing cells in immunized animals before arthritis induction led to increased cellular and humoral immune responses to the inducing antigen (methylated bovine serum albumin; mBSA) and autoantigens, and to an exacerbation of arthritis, as indicated by clinical (knee joint swelling) and histological scores. Transfer of CD4(+)CD25(+ )cells into immunized mice at the time of induction of antigen-induced arthritis decreased the severity of disease but was not able to cure established arthritis. No significant changes in mBSA-specific immune responses were detected. In vivo migration studies showed a preferential accumulation of CD4(+)CD25(+ )cells in the inflamed joint as compared with CD4(+)CD25(- )cells. These data imply a significant role for CD4(+)CD25(+ )T(reg )cells in the control of chronic arthritis. However, transferred T(reg )cells appear to be unable to counteract established acute or chronic inflammation. This is of considerable importance for the timing of T(reg )cell transfer in potential therapeutic applications
Global patterns of ecologically unequal exchange:Implications for sustainability in the 21st century
Ecologically unequal exchange theory posits asymmetric net flows of biophysical resources from poorer to richer countries. To date, empirical evidence to support this theoretical notion as a systemic aspect of the global economy is largely lacking. Through environmentally-extended multi-regional input-output modelling, we provide empirical evidence for ecologically unequal exchange as a persistent feature of the global economy from 1990 to 2015. We identify the regions of origin and final consumption for four resource groups: materials, energy, land, and labor. By comparing the monetary exchange value of resources embodied in trade, we find significant international disparities in how resource provision is compensated. Value added per ton of raw material embodied in exports is 11 times higher in high-income countries than in those with the lowest income, and 28 times higher per unit of embodied labor. With the exception of embodied land for China and India, all other world regions serve as net exporters of all types of embodied resources to high-income countries across the 1990â2015 time period. On aggregate, ecologically unequal exchange allows high-income countries to simultaneously appropriate resources and to generate a monetary surplus through international trade. This has far-reaching implications for global sustainability and for the economic growth prospects of nations
Development of a core outcome set to use in the research and assessment of malignant bowel obstruction: protocol for the RAMBO study
INTRODUCTION: Studies regarding the management of malignant bowel obstruction (MBO) report conflicting findings. This is partly due to different outcome measures being used to evaluate severity of MBO and the response to treatments. Furthermore, current outcome measures focus mainly on measurable physiological parameters which may not correlate strongly with patient-defined quality of life. The development of core outcome sets allows a consistent approach to evaluating clinical conditions taking into consideration patient, healthcare professional and researcher viewpoints. It follows an internationally recognised standard methodology. We present a protocol for the development of a core outcome set for Research and Assessment of MBO (RAMBO). METHODS: RAMBO is a multicentre study, comprising of four phases: a systematic review to examine current scope of outcome measures associated with MBO (phase I). Interviews with patients, companions and healthcare professionals will explore priorities and preferences for care and outcomes (phase II). An expert panel meeting will collate the findings into a set of outcomes (phase III), refined by consensus through a Delphi survey with key stakeholders (phase IV). The final set of outcomes will be ratified at a consensus meeting. Each step will actively include patient partners. Thematic analysis and descriptive statistics will be used to analyse qualitative and quantitative data, respectively. ETHICS AND DISSEMINATION: Ethical approval was obtained (Wales REC 5, REF: 19/LO/1876). Study participants and relevant stakeholders will be updated with newsletters and a lay summary at the end of the study. Abstracts will be submitted to national and international conferences, result papers will be submitted to peer-reviewed, open access journals. TRIAL AND PROSPERO REGISTRATION NUMBERS: Core Outcome Measures in Effectiveness Trials (1402); Systematic Literature Review (CRD42019150648); Rapid Review (CRD42020176393)
Developmental Stage, Phenotype, and Migration Distinguish Naive- and Effector/Memory-like CD4+ Regulatory T Cells
Regulatory T cells (Tregs) fulfill a central role in immune regulation. We reported previously that the integrin αEÎČ7 discriminates distinct subsets of murine CD4+ regulatory T cells. Use of this marker has now helped to unravel a fundamental dichotomy among regulatory T cells. αEâCD25+ cells expressed L-selectin and CCR7, enabling recirculation through lymphoid tissues. In contrast, αE-positive subsets (CD25+ and CD25â) displayed an effector/memory phenotype expressing high levels of E/P-selectinâbinding ligands, multiple adhesion molecules as well as receptors for inflammatory chemokines, allowing efficient migration into inflamed sites. Accordingly, αE-expressing cells were found to be the most potent suppressors of inflammatory processes in disease models such as antigen-induced arthritis
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
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