1,087 research outputs found
Bound states and extended states around a single vortex in the d-wave superconductors
Making use of the Bogoliubov-de Gennes equation for the d-wave
superconductors, we investigate the quasi-particle spectrum around a single
vortex. Taking , we found that there are bound states which are
localized around the vortex core, and extended states which are rather uniform,
for where is the quasi-particle energy and is the
asymptotic value of the order parameter for away from the vortex.Comment: 4 pages, 6 figure
Ford's Procedure for Combining Multiple Sets of Partially Ordered Data
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66929/2/10.1177_001316447303300104.pd
Book Reviews : The Optimum Utilization of Knowledge: Making Knowledge Serve Human Betterment. Kenneth E. Boulding and Lawrence Senesh, eds. (Boulder, CO: Westview Press, 1983) 382 pp
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68936/2/10.1177_107554708400600106.pd
Direct Measurement of Quantum Confinement Effects at Metal to Quantum-Well Nanocontacts
Model metal-semiconductor nanostructure Schottky nanocontacts were made on cleaved heterostructures containing GaAs quantum wells (QWs) of varying width and were locally probed by ballistic electron emission microscopy. The local Schottky barrier was found to increase by ∼0.140 eV as the QW width was systematically decreased from 15 to 1 nm, due mostly to a large (∼0.200 eV) quantum-confinement increase to the QW conduction band. The measured barrier increase over the full 1 to 15 nm QW range was quantitatively explained when local "interface pinning" and image force lowering effects are also considered
Global rank-invariant set normalization (GRSN) to reduce systematic distortions in microarray data
<p>Abstract</p> <p>Background</p> <p>Microarray technology has become very popular for globally evaluating gene expression in biological samples. However, non-linear variation associated with the technology can make data interpretation unreliable. Therefore, methods to correct this kind of technical variation are critical. Here we consider a method to reduce this type of variation applied after three common procedures for processing microarray data: MAS 5.0, RMA, and dChip<sup>®</sup>.</p> <p>Results</p> <p>We commonly observe intensity-dependent technical variation between samples in a single microarray experiment. This is most common when MAS 5.0 is used to process probe level data, but we also see this type of technical variation with RMA and dChip<sup>® </sup>processed data. Datasets with unbalanced numbers of up and down regulated genes seem to be particularly susceptible to this type of intensity-dependent technical variation. Unbalanced gene regulation is common when studying cancer samples or genetically manipulated animal models and preservation of this biologically relevant information, while removing technical variation has not been well addressed in the literature. We propose a method based on using rank-invariant, endogenous transcripts as reference points for normalization (GRSN). While the use of rank-invariant transcripts has been described previously, we have added to this concept by the creation of a global rank-invariant set of transcripts used to generate a robust average reference that is used to normalize all samples within a dataset. The global rank-invariant set is selected in an iterative manner so as to preserve unbalanced gene expression. Moreover, our method works well as an overlay that can be applied to data already processed with other probe set summary methods. We demonstrate that this additional normalization step at the "probe set level" effectively corrects a specific type of technical variation that often distorts samples in datasets.</p> <p>Conclusion</p> <p>We have developed a simple post-processing tool to help detect and correct non-linear technical variation in microarray data and demonstrate how it can reduce technical variation and improve the results of downstream statistical gene selection and pathway identification methods.</p
Expression of Chemoresistance-Related Genes and Heat Shock Protein 72 in Hyperthermic Isolated Limb Perfusion of Malignant Melanoma: An Experimental Study
Hyperthermic isolated limb perfusion (HILP) is considered an established treatment for multiple locoregional intransit metastases in malignant melanoma of the extremities. Various mechanisms such as the expression of chemoresistance genes and heat shock proteins by the tumor may be responsible for varying response rates and locoregional recurrences of the treatment. The aim of the experimental animal study was to investigate the direct impact of HILP on such mechanisms of resistance. Tissue temperature, administration of the cytostatic drug, and duration of perfusion were varied. Expression of the chemoresistance genes mdr1, mrp1, mrp2, and lrp and of heat shock protein 72 (HSP72) in the tumor tissue was analysed using RT-PCR and western blot analysis. The untreated SK-MEL-3 tumor expressed mdr1, mrp1, and lrp, but not mrp2. Neither variation of temperature, administration of the cytostatic drug, nor duration of perfusion changed the expression of this “resistance pattern”. In contrast to the cytostatic drug, hyperthermia causes a persistent induction of HSP72. Both observations could offer a potential explanation for failure of HILP in malignant melanoma
Caution profile and driving record of undergraduate males
With a device called an Apprehension Meter, 60 undergraduate males watched a 5-min film of highway driving as seen from the driver's seat and recorded a moment-by-moment judgment of degree of danger, or caution level. From responses to six discrete hazards and to intervening uneventful periods, several summary scores were derived of which five differentiated significantly by driving record. The Safe Record group remained more cautious during the uneventful (baseline) periods, reacted to hazards sooner but more gradually, relaxed more gradually after their disappearance, and consequently remained alert to each hazard longer. The Violations group were at the other extreme, and the Accidents group intermediate. Hence the Safe group appeared more prompt in detecting danger, but less abrupt in responding to it, than did the groups with infractions. In terms of consistency across six hazards or 10 baselines, reliability (Cronbach's alpha) ranged from 0.48 to 0.99. A composite caution index had an alpha of 0.85 across hazards and correctly classified 77 per cent of subjects as either safe or non-safe. The results were found consistent with those in other studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22284/1/0000724.pd
The analytic structure of 2D Euler flow at short times
Using a very high precision spectral calculation applied to the
incompressible and inviscid flow with initial condition , we find that the width of its analyticity
strip follows a law at short times over eight decades. The
asymptotic equation governing the structure of spatial complex-space
singularities at short times (Frisch, Matsumoto and Bec 2003, J.Stat.Phys. 113,
761--781) is solved by a high-precision expansion method. Strong numerical
evidence is obtained that singularities have infinite vorticity and lie on a
complex manifold which is constructed explicitly as an envelope of analyticity
disks.Comment: 19 pages, 14 figures, published versio
Quantum well behavior of single stacking fault 3C inclusions in 4H-SiC p-i-n diodes studied by ballistic electron emission microscopy
We show that "single" stacking fault 3C inclusions formed in 4H-SiC p-i-n diodes behave as electron quantum wells (QWs) with the QW energy depth of ???0.25 eV below 4H-SiC conduction band minimum, by measuring the Schottky barriers on and away from inclusions with ballistic electron emission microscopy (BEEM). The Schottky barrier on the 4H area ([11-20] oriented) is measured to be essentially the same as (0001) plane studied previously, indicating that the interface pinning effects on both crystal faces are almost identical. Additionally, BEEM current amplitude is observed to be very sensitive to subsurface damage induced by polishing.open91
Distribution and frequency of VKORC1 sequence variants conferring resistance to anticoagulants in Mus musculus
Pelz, H.-J., Rost, S., Müller, E., Esther, A., Ulrich, R.G., Müller, C.R
- …