9,976 research outputs found
Multispectral scanner optical system
An optical system for use in a multispectral scanner of the type used in video imaging devices is disclosed. Electromagnetic radiation reflected by a rotating scan mirror is focused by a concave primary telescope mirror and collimated by a second concave mirror. The collimated beam is split by a dichroic filter which transmits radiant energy in the infrared spectrum and reflects visible and near infrared energy. The long wavelength beam is filtered and focused on an infrared detector positioned in a cryogenic environment. The short wavelength beam is dispersed by a pair of prisms, then projected on an array of detectors also mounted in a cryogenic environment and oriented at an angle relative to the optical path of the dispersed short wavelength beam
An investigation into the archaeological application of carbon stable isotope analysis used to establish crop water availability: solutions and ways forward
Carbon stable isotope analysis of charred cereal remains
is a relatively new method employed by archaeological
scientists to investigate ancient climate and irrigation
regimes. The aim of this study was to assess the effect of
environmental variables on carbon isotope
discrimination (D) in multiple environments to develop
the technique and its archaeological application, using
crops grown at three experimental stations in Jordan.
There are two key results: (1) as expected, there was a
strong positive relationship between water availability
and D; (2) site, not water input, was the most important
factor in determining D. Future work should concentrate
on establishing ways of correcting D for the influence of
site specific environmental variables and on assessing
how well carbon isotope discrimination values are
preserved within the archaeological record
Innovations from being inclusive: PPI for health of the public(s)
A presentation of a PhD study focused on professionals' views of children's involvement in research. Findings suggest that the potential benefits of inclusive, representative and diverse PPI identified in this study, bear relevance to all 'publics' and across a range of public health issues
The development of an unconventional food regeneration process: Quantifying the nutritional components of a model methylotrophic yeast
A hybrid chemical/biological approach to unconventional food regeneration is discussed. Carbon dioxide and water, the major wastes of human metabolism would be converted to methanol by one of several physiochemical processes available (thermal, photocatalytic, etc.). Methanol is then used to supply carbon and energy for the culture of microorganisms which in turn produce biological useful basic food stuffs for human nutrition. Our work has focused on increasing the carbohydrate levels of a candidate methylotrophic yeast to more nearly coincide with human nutritional requirements. Yeasts were chosen due to their high carbohydrate levels compared to bacteria and their present familiarity in the human diet. The initial candidate yeast studied was a thermotolerant strain of Hansenula polymor pha, DL-1. The quantitative results that permit an evaluation of the overall efficiency in hybrid chemical/biological food production schemes are discussed. A preliminary evaluation of the overall efficiency of such schemes is also discussed
Impedance of a sphere oscillating in an elastic medium with and without slip
The dynamic impedance of a sphere oscillating in an elastic medium is
considered. Oestreicher's formula for the impedance of a sphere bonded to the
surrounding medium can be expressed simply in terms of three lumped impedances
associated with the displaced mass and the longitudinal and transverse waves.
If the surface of the sphere slips while the normal velocity remains
continuous, the impedance formula is modified by adjusting the definition of
the transverse impedance to include the interfacial impedance.Comment: 10 pages, 2 figure
Complex trajectory method in time-dependent WKB
We present a significant improvement to a time-dependent WKB (TDWKB)
formulation developed by Boiron and Lombardi [JCP {\bf108}, 3431 (1998)] in
which the TDWKB equations are solved along classical trajectories that
propagate in the complex plane. Boiron and Lombardi showed that the method
gives very good agreement with the exact quantum mechanical result as long as
the wavefunction does not exhibit interference effects such as oscillations and
nodes. In this paper we show that this limitation can be overcome by
superposing the contributions of crossing trajectories. We also demonstrate
that the approximation improves when incorporating higher order terms in the
expansion. These improvements could make the TDWKB formulation a competitive
alternative to current time-dependent semiclassical methods
Modulation of TGF-beta signaling by proinflammatory cytokines in articular chondrocytes.
OBJECTIVE: The normal structure and function of articular cartilage are the result of a precisely balanced interaction between anabolic and catabolic processes. The transforming growth factor-beta (TGF-beta) family of growth factors generally exerts an anabolic or repair response; in contrast, proinflammatory cytokines such as interleukin 1 beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) exert a strong catabolic effect. Recent evidence has shown that IL-1beta, and TNF-alpha, and the TGF-beta signaling pathways share an antagonistic relationship. The aim of this study was to determine whether the modulation of the response of articular chondrocytes to TGF-beta by IL-1beta or TNF-alpha signaling pathways occurs through regulation of activity and availability of mothers against DPP (Drosophila) human homologue (Smad) proteins.
METHODS: Human articular chondrocytes isolated from knee joints from patients with osteoarthritis (OA) or normal bovine chondrocytes were cultured in suspension in poly-(2-hydroxyethyl methacrylate)-coated dishes with either 10% fetal bovine serum media or serum-deprived media 6h before treatment with IL-1beta alone, TNF-alpha alone or IL-1beta followed by TGF-beta. Nuclear extracts were examined by electrophoretic mobility-shift assays (EMSA) for nuclear factor-kappa B (NF-kappaB) and Smad3/4 deoxyribonucleic acid (DNA) binding. Nuclear extracts were also subjected to the TranSignal Protein/DNA array (Panomics, Redwood City, CA) enabling the simultaneous semiquantitative assessment of DNA-binding activity of 54 different transcription factors. Nuclear phospho-Smad2/3 and total Smad7 protein expression in whole cell lysates were studied by Western blot. Cytoplasmic Smad7, type II collagen alpha 1 (COL2A1), aggrecan and SRY-related high mobility group-Box gene 9 (SOX-9) mRNA expression were measured by real-time polymerase chain reaction (PCR).
RESULTS: The DNA-binding activity of Smad3/4 in the TranSignal Protein/DNA array was downregulated by TNF-alpha (46%) or IL-1beta treatment (42%). EMSA analysis showed a consistent reduction in Smad3/4 DNA-binding activity in human articular chondrocytes treated with IL-1beta or TNF-alpha. TGF-beta-induced Smad3/4 DNA-binding activity and Smad2/3 phosphorylation were also reduced following pretreatment with IL-1beta in human OA and bovine chondrocytes. Real-time PCR and Western blot analysis showed that IL-1beta partially reversed the TGF-beta stimulation of Smad7 mRNA and protein levels in TGF-beta-treated human OA cells. In contrast, TGF-beta-stimulated COL2A1, aggrecan, and SOX-9 mRNA levels were abrogated by IL-1beta.
CONCLUSIONS: IL-1beta or TNF-alpha exerted a suppressive effect on Smad3/4 DNA-binding activity in human articular chondrocytes, as well as on TGF-beta-induced stimulation of Smad3/4 DNA-binding activity and Smad2/3 phosphorylation in human OA and bovine articular chondrocytes. IL-1beta partially reversed the increase in TGF-beta-stimulated Smad7 mRNA or protein levels suggesting that Smad7 may not be involved in the suppression of TGF-beta signaling induced by IL-1beta or TNF-alpha in articular chondrocytes. The balance between the IL-1beta or TNF-alpha and the TGF-beta signaling pathways is crucial for maintenance of articular cartilage homeostasis and its disruption likely plays a substantial role in the pathogenesis of OA
Stochastic Stokes' drift of a flexible dumbbell
We consider the stochastic Stokes drift of a flexible dumbbell. The dumbbell
consists of two isotropic Brownian particles connected by a linear spring with
zero natural length, and is advected by a sinusoidal wave. We find an
asymptotic approximation for the Stokes drift in the limit of a weak wave, and
find good agreement with the results of a Monte Carlo simulation. We show that
it is possible to use this effect to sort particles by their flexibility even
when all the particles have the same diffusivity.Comment: 12 pages, 1 figur
EAGLEView: A surface and grid generation program and its data management
An old and proven grid generation code, the EAGLE grid generation package, is given an added dimension of a graphical interface and a real time data base manager. The Numerical Aerodynamic Simulation (NAS) Panel Library is used for the graphical user interface. Through the panels, EAGLEView constructs the EAGLE script command and sends it to EAGLE to be processed. After the object is created, the script is saved in a mini-buffer which can be edited and/or saved and reinterpreted. The graphical objects are set-up in a linked-list and can be selected or queried by pointing and clicking the mouse. The added graphical enhancement to the EAGLE system emphasizes the unique capability to construct field points around complex geometry and visualize the construction every step of the way
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