1,965 research outputs found
Home monitoring of foot skin temperatures to prevent ulceration
OBJECTIVE - To evaluate the effectiveness of at-home infrared temperature monitoring as a preventative tool in individuals at high risk for diabetes-related lower-extremity ulceration and amputation. RESEARCH DESIGN AND METHODS - Eighty-five patients who fit diabetic foot risk category 2 or 3 (neuropathy and foot deformity or previous history of ulceration or partial foot amputation) were randomized into a standard therapy group (n = 41) or an enhanced therapy group (n = 44). Standard therapy consisted of therapeutic footwear, diabetic foot education, and regular foot evaluation by a podiatrist. Enhanced therapy included the addition of a handheld infrared skin thermometer to measure temperatures on the sole of the foot in the morning and evening. Elevated temperatures (>4°F compared with the opposite foot) were considered to be "at risk" of ulceration due to inflammation at the site of measurement. When foot temperatures were elevated, subjects were instructed to reduce their activity and contact the study nurse. Study subjects were followed for 6 months. RESULTS - The enhanced therapy group had significantly fewer diabetic foot complications (enhanced therapy group 2% vs. standard therapy group 20%, P = 0.01, odds ratio 10.3, 95% CI 1.2-85.3). There were seven ulcers and two Charcot fractures among standard therapy patients and one ulcer in the enhanced therapy group. CONCLUSIONS - These results suggest that at-home patient self-monitoring with daily foot temperatures may be an effective adjunctive tool to prevent foot complications in individuals at high risk for lower-extremity ulceration and amputation
Efficient sorting of free electron orbital angular momentum
We propose a method for sorting electrons by orbital angular momentum (OAM). Several methods now exist to prepare electron wavefunctions in OAM states, but no technique has been developed for efficient, parallel measurement of pure and mixed electron OAM states. The proposed technique draws inspiration from the recent demonstration of the sorting of OAM through modal transformation. We show that the same transformation can be performed on electrons with electrostatic optical elements. Specifically, we show that a charged needle and an array of electrodes perform the transformation and phase correction necessary to sort OAM states. This device may enable the analysis of the spatial mode distribution of inelastically scattered electrons
Experimental Demonstration of Geometrically-Shaped Constellations Tailored to the Nonlinear Fibre Channel
A geometrically-shaped 256-QAM constellation, tailored to the nonlinear
optical fibre channel, is experimentally demonstrated. The proposed
constellation outperforms both uniform and AWGN-tailored 256-QAM, as it is
designed to optimise the trade-off between shaping gain, nonlinearity and
transceiver impairments
Unraveling proteins: A molecular mechanics study
An internal coordinate molecular mechanics study of unfolding peptide chains by external stretching has been carried out to predict the type of force spectra that may be expected from single-molecule manipulation experiments currently being prepared. Rather than modeling the stretching of a given protein, we have looked at the behavior of simple secondary structure elements (alpha-helix, beta-ribbon, and interacting alpha-helices) to estimate the magnitude of the forces involved in their unfolding or separation and the dependence of these forces on the way pulling is carried out as well as on the length of the structural elements. The results point to a hierarchy of forces covering a surprisingly large range and to important orientational effects in the response to external stress
A novel N-terminal extension in mitochondrial TRAP1 serves as a thermal regulator of chaperone activity.
Hsp90 is a conserved chaperone that facilitates protein homeostasis. Our crystal structure of the mitochondrial Hsp90, TRAP1, revealed an extension of the N-terminal β-strand previously shown to cross between protomers in the closed state. In this study, we address the regulatory function of this extension or 'strap' and demonstrate its responsibility for an unusual temperature dependence in ATPase rates. This dependence is a consequence of a thermally sensitive kinetic barrier between the apo 'open' and ATP-bound 'closed' conformations. The strap stabilizes the closed state through trans-protomer interactions. Displacement of cis-protomer contacts from the apo state is rate-limiting for closure and ATP hydrolysis. Strap release is coupled to rotation of the N-terminal domain and dynamics of the nucleotide binding pocket lid. The strap is conserved in higher eukaryotes but absent from yeast and prokaryotes suggesting its role as a thermal and kinetic regulator, adapting Hsp90s to the demands of unique cellular and organismal environments
MB2.1 - Coherent Technologies for Passive Optical Networks (Invited)
To date, optical access networks have been exclusively based on intensity modulation with direct detection. However, recent advances in coherent transceivers offer the potential to overcome the many limitations of these systems. This work reviews such candidate technologies for low complexity coherent optical access networks
DNA: From rigid base-pairs to semiflexible polymers
The sequence-dependent elasticity of double-helical DNA on a nm length scale
can be captured by the rigid base-pair model, whose strains are the relative
position and orientation of adjacent base-pairs. Corresponding elastic
potentials have been obtained from all-atom MD simulation and from
high-resolution structural data. On the scale of a hundred nm, DNA is
successfully described by a continuous worm-like chain model with homogeneous
elastic properties characterized by a set of four elastic constants, which have
been directly measured in single-molecule experiments. We present here a theory
that links these experiments on different scales, by systematically
coarse-graining the rigid base-pair model for random sequence DNA to an
effective worm-like chain description. The average helical geometry of the
molecule is exactly taken into account in our approach. We find that the
available microscopic parameters sets predict qualitatively similar mesoscopic
parameters. The thermal bending and twisting persistence lengths computed from
MD data are 42 and 48 nm, respectively. The static persistence lengths are
generally much higher, in agreement with cyclization experiments. All
microscopic parameter sets predict negative twist-stretch coupling. The
variability and anisotropy of bending stiffness in short random chains lead to
non-Gaussian bend angle distributions, but become unimportant after two helical
turns.Comment: 13 pages, 6 figures, 6 table
Searching (the) FIRST radio arcs near ACO clusters
Gravitational lensing (GL) of distant radio sources by galaxy clusters should
produce radio arc(let)s. We extracted radio sources from the FIRST survey near
Abell cluster cores and found their radio position angles to be uniformly
distributed with respect to the cluster centres. This result holds even when we
restrict the sample to the richest or most centrally condensed clusters, and to
sources with high S/N and large axial ratio. Our failure to detect GL with
statistical methods may be due to poor cluster centre positions. We did not
find convincing candidates for arcs either. Our result agrees with theoretical
estimates predicting that surveys much deeper than FIRST are required to detect
the effect. This is in apparent conflict with the detection of such an effect
claimed by Bagchi & Kapahi (1995).Comment: 6 pages; 8 figures and 1 style file are included; to appear in Proc.
"Observational Cosmology with the New Radio Surveys", eds. M. Bremer, N.
Jackson & I. Perez-Fournon, Kluwer Acad. Pres
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