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Electron beam compression with electric and magnetic fields
Electron beam compression with electrostatic and magnetostatic field
A preliminary evaluation of a new control-knob design for electronic equipment
Two experiments were carried out using five subjects to compare
performance using standard and flush fitting rotary controls for electronic
equipment. It vas found that the flush knob could be rotated more quickly
through several revolutions, but a given setting accuracy was achieved less
quickly using this flush knob.
Some of the more general advantages and disadvantages of the flush
knob are outlined.
It should be noted that the primary objective of this study was to
provide the participants with some experience in carrying out Human Factors
studies and the time allowed was not such as to permit a comprehensive
evaluation of the new knob design
Laminin and fibronectin in rectal adenocarcinoma: relationship to tumour grade, stage and metastasis.
Using an immunoperoxidase procedure, we have examined the distribution of laminin and fibronectin in normal human large intestinal mucosa and in 50 cases of rectal adenocarcinoma for which extensive clinical follow up was available. In normal tissue, laminin staining was largely restricted to basement membranes, including that underlying the epithelial cells, whereas fibronectin was found in both basement membranes and surrounding connective tissue. In rectal carcinomas, basement membrane-like staining for laminin associated with tumour cells was found in only 27 out of the 50 cases studied. Statistical analysis showed that the presence of laminin-containing basement membranes was correlated with low histological grade (well-differentiated tumours), but not with stage (progression through the bowel wall and the development of lymph node metastases) and, in a highly significant way, with a reduced incidence of distant metastases and increased patient survival. Although fibronectin was found in tumour cell basement membranes where these were present, it was also found in the stroma of all 50 tumours. There was no apparent correlation between the presence of stromal fibronectin and grade, stage or development of metastases. Finally, attention is drawn to some of the technical difficulties in detecting basement membrane antigens in formalin-fixed tissue, the material most frequently available for retrospective study
An electron Talbot interferometer
The Talbot effect, in which a wave imprinted with transverse periodicity
reconstructs itself at regular intervals, is a diffraction phenomenon that
occurs in many physical systems. Here we present the first observation of the
Talbot effect for electron de Broglie waves behind a nanofabricated
transmission grating. This was thought to be difficult because of Coulomb
interactions between electrons and nanostructure gratings, yet we were able to
map out the entire near-field interference pattern, the "Talbot carpet", behind
a grating. We did this using a Talbot interferometer, in which Talbot
interference fringes from one grating are moire'-filtered by a 2nd grating.
This arrangement has served for optical, X-ray, and atom interferometry, but
never before for electrons. Talbot interferometers are particularly sensitive
to distortions of the incident wavefronts, and to illustrate this we used our
Talbot interferometer to measure the wavefront curvature of a weakly focused
electron beam. Here we report how this wavefront curvature demagnified the
Talbot revivals, and we discuss applications for electron Talbot
interferometers.Comment: 5 pages, 5 figures, updated version with abstrac
Lack of correlation between metastasis of human rectal carcinoma and the absence of stromal fibronectin.
In a retrospective study we have used an immunoperoxidase procedure to localize the glycoprotein fibronectin in human rectal carcinomas, concentrating on tumour invading thick-walled extramural veins. Fibronectin was present in 29 out of 38 cases, in connective tissue stroma, and was not in direct association with the tumour cells, except in areas of necrosis. We found no correlation between the presence or absence of stromal fibronectin and (1) the degree of cellular differentiation within the tumour, (2) tumour progression (Dukes' classification) (3) the subsequent development of metastases and (4) patient longevity. OUr results do not support the conclusions from in vitro studies (Smith et al., 1979) that the metastatic potential of carcinomas may be partly determined by the ability of tumour cells to synthesize pericellular fibronectin
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Sources of upper tropospheric HOx over the South Pacific Convergence Zone: A case study
Adsorption of colloidal particles in the presence of external field
We present a new class of sequential adsorption models in which the adsorbing
particles reach the surface following an inclined direction (shadow models).
Capillary electrophoresis, adsorption in the presence of a shear or on an
inclined substrate are physical manifestations of these models. Numerical
simulations are carried out to show how the new adsorption mechanisms are
responsible for the formation of more ordered adsorbed layers and have
important implications in the kinetics, in particular modifying the jamming
limit.Comment: LaTex file, 3 figures available upon request, to appear in
Phys.Rev.Let
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