4,429 research outputs found
Medical diagnosis system and method with multispectral imaging
A skin diagnosis system includes a scanning and optical arrangement whereby light reflected from each incremental area (pixel) of the skin is directed simultaneously to three separate light filters, e.g., IR, red, and green. As a result, the three devices simultaneously produce three signals which are directly related to the reflectance of light of different wavelengths from the corresponding pixel. These three signals for each pixel after processing are used as inputs to one or more output devices to produce a visual color display and/or a hard copy color print, for one usable as a diagnostic aid by a physician
Effect of Facial Encumbrance on Excimer Formation and Charge Resonance Stabilization in Model Bichromophoric Assemblies
Excimer formation and charge resonance stabilization in covalently linked bichromophoric systems with flexible spacers are important processes relevant to biochemistry and functional materials. Requiring a π-stacked cofacial arrangement of a pair of aromatic molecules at a van der Waals contact, the underlying geometrical reorganization that accompanies these events continues to be debated. Here we use a variety of methods including two-color resonant two-photon ionization spectroscopy (2CR2PI), ion yield measurements, hole-burning spectroscopy (HB), and laser-induced fluorescence (LIF) excitation and emission spectroscopy to compare the gas-phase spectroscopy and dynamics of the van der Waals dimers of fluorene, 9-methylfluorene (MF), and 9,9′-dimethylfluorene (F1). The goal of this work is to probe the influence of methyl substitution on the dynamics of excimer formation and charge resonance (CR) stabilization. The fluorene dimer, (F)2, displays lifetime broadened electronic spectra and the dominance of excimer emission, consistent with a rapid (picoseconds) formation of a π-stacked excimer upon electronic excitation. Ion yield measurements of (F)2 reveal a lowering of the ionization potential (IP) by some 0.38 eV relative to the monomer, reflecting significant CR stabilization. These trends are mirrored in the 9-methylfluorene dimer, (MF)2, as one face of the π-system remains open. In contrast, the electronic spectrum of the dimethyl-substituted dimer, (F1)2, shows narrow features representing a single band system, and analysis of the torsional structure in dispersed fluorescence spectra identifies this as emission from the locally excited state of a tilted (non-π-stacked) dimer, with no evidence of excimeric emission. The structure of this dimer reflects the increased importance of C–H/π interactions in the dimethyl-substituted system, as increased steric constraints block a cofacial approach. The IP of (F1)2 shows CR stabilization which is roughly 1/2 of that in π-stacked (F)2 dimer. Extensive theoretical calculations support these findings and show the importance of sandwich-type configurations for excitonic delocalization and CR stabilization
Objective measurement of habitual sedentary behavior in pre-school children: comparison of activPAL with actigraph monitors
The Actigraph is well established for measurement of both physical activity and
sedentary behavior in children. The activPAL is being used increasingly in children, though with no published evidence on its use in free-living children to date. The present study compared the two monitors in preschool children. Children (n 23) wore both monitors simultaneously during waking hours for 5.6d and 10h/d. Daily mean percentage of time sedentary (nontranslocation of the trunk) was 74.6 (SD 6.8) for the Actigraph and 78.9 (SD 4.3) for activPAL. Daily mean percentage of time physically active (light intensity physical activity plus MVPA) was 25.4 (SD 6.8) for the Actigraph and 21.1 (SD 4.3) for the activPAL. Bland-Altman tests and paired t tests suggested small but statistically significant differences between the two monitors. Actigraph and activPAL estimates of sedentary behaviour and physical activity in young children are similar at a group level
Made in America? Assumptions About Service Learning Pedagogy as Transnational: A Comparison Between Ireland and the United States
Using exploratory, qualitative interviews, the authors studied conceptions of academic service-learning in the United States and the Republic of Ireland in order to elucidate the ways in which culture and social context shaped practitioners\u27 perceptions and practices regarding service-learning pedagogy. Participants articulated a shared understanding of service-learning, identified similar barriers to utilizing service-learning and institutionalizing its practice, and discussed tensions surrounding the purpose of service-learning. However, Irish participants distanced their practice from the historical and cultural context of U.S. service-learning, demonstrating the process of localization. We conclude that the overarching tenets of service-learning may be transferable but the social, cultural, economic, historical, and political conditions of individual countries define how these are to be achieved
Local origins impart conserved bone type-related differences in human osteoblast behaviour
Osteogenic behaviour of osteoblasts from trabecular, cortical and subchondral bone were examined to determine any bone type-selective differences in samples from both osteoarthritic (OA) and osteoporotic (OP) patients. Cell growth, differentiation; alkaline phosphatase (TNAP) mRNA and activity, Runt-related transcription factor-2 (RUNX2), SP7-transcription factor (SP7), bone sialoprotein-II (BSP-II), osteocalcin/bone gamma-carboxyglutamate (BGLAP), osteoprotegerin (OPG, TNFRSF11B), receptor activator of nuclear factor-κβ ligand (RANKL, TNFSF11) mRNA levels and proangiogenic vascular endothelial growth factor-A (VEGF-A) mRNA and protein release were assessed in osteoblasts from paired humeral head samples from age-matched, human OA/OP (n = 5/4) patients. Initial outgrowth and increase in cell number were significantly faster (p < 0.01) in subchondral and cortical than trabecular osteoblasts, in OA and OP, and this bone type-related differences were conserved despite consistently faster growth in OA. RUNX2/SP7 levels and TNAP mRNA and protein activity were, however, greater in trabecular than subchondral and cortical osteoblasts in OA and OP. BSP-II levels were significantly greater in trabecular and lowest in cortical osteoblasts in both OA and OP. In contrast, BGLAP levels showed divergent bone type-selective behaviour; highest in osteoblasts from subchondral origins in OA and trabecular origins in OP. We found virtually identical bone type-related differences, however, in TNFRSF11B:TNFSF11 in OA and OP, consistent with greater potential for paracrine effects on osteoclasts in trabecular osteoblasts. Subchondral osteoblasts (OA) exhibited highest VEGF-A mRNA levels and release. Our data indicate that human osteoblasts in trabecular, subchondral and cortical bone have inherent, programmed diversity, with specific bone type-related differences in growth, differentiation and pro-angiogenic potential in vitro
Emissions Pricing to Stablize Global Climate
http://globalchange.mit.edu/research/publications/2241In the absence of significant greenhouse gas (GHG) mitigation, many analysts project that
atmospheric concentrations of species identified for control in the Kyoto protocol could exceed 1000
ppm (carbon-dioxide-equivalent) by 2100 from the current levels of about 435 ppm. This could lead
to global average temperature increases of between 2.5° and 6° C by the end of the century. There
are risks of even greater warming given that underlying uncertainties in emissions projections and
climate response are substantial. Stabilization of GHG concentrations that would have a reasonable
chance of meeting temperature targets identified in international negotiations would require
significant reductions in GHG emissions below “business-as-usual” levels, and indeed from present
emissions levels. Nearly universal participation of countries is required, and the needed investments
in efficiency and alternative energy sources would entail significant costs. Resolving how these
additional costs might be shared among countries is critical to facilitating a wide participation of
large-emitting countries in a climate stabilization policy. The 2°C target is very ambitious given
current atmospheric concentrations and inertia in the energy and climate system. The Copenhagen
pledges for 2020 still keep the 2°C target within a reach, but very aggressive actions would be
needed immediately after that
Environmental monitoring of Mycobacterium bovis in badger feces and badger sett soil by real-time PCR, as confirmed by immunofluorescence, immunocapture, and cultivation
Real-time PCR was used to detect and quantify Mycobacterium bovis cells in
naturally infected soil and badger faeces. Immunomagnetic capture,
immunofluorescence and selective culture confirmed species identification and cell
viability. These techniques will prove useful for monitoring M. bovis in the
environment and for elucidating transmission routes between wildlife and cattle
- …