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Magnetic Attraction (magnetic + attraction)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

A Method to Intraoperatively Assess Stapes Prostheses for Magnetic Attraction,

THE LARYNGOSCOPE, Issue 12 2003
David W. White MD
Abstract Objective To present a technique used to assess metallic otologic protheses for magnetic susceptibility during surgery. Study Design Description of a surgical technique. Methods A sterile handheld pacemaker magnet is used to evaluate the prothesis prior to implantation. The magnet is placed over the prosthesis and the prosthesis is placed directly on the magnet. Any evidence of magnetic attraction and the prosthesis is rejected prior to implantation. Results None of the prostheses screened showed any magnetic attraction. As a control, steel wire was cut into pieces with dimensions similar to prostheses. These sections of wire were readily attracted to the magnet. Conclusions Intraoperative screening of metallic prostheses for magnetic susceptibility is possible using a sterile handheld pacemaker magnet. [source]

ERK activation by mechanical strain is regulated by the small G proteins rac-1 and rhoA

EXPERIMENTAL DERMATOLOGY, Issue 2 2004
Julien Laboureau
Abstract: Physical forces play an important role in regulating cell functions. We applied mechanical strain to human fibroblasts by magnetic attraction of superparamagnetic arginine-glycine-aspartic acid (RGD)-coated beads. We confirmed that the MAP kinases Erk and p38 are activated by mechanical strain, and went further by demonstrating the activation of Elk-1 by mechanical strain, mainly through a MEK-Erk pathway. Transfection of a dominant negative form of the G protein rac-1 (rac T17N), and inhibition of PI3K, an effector of rac-1, efficiently prevented Elk-1 activation by mechanical forces. Transfection with C3 transferase, known to inhibit rhoA, and inhibition of rock (a downstream effector of rhoA), gave similar results. However, contrary to the active form of rhoA (rho G14V), transfection of the active form of rac-1 (rac G12V) induced Elk activation and mimicked the effects of mechanical strain. These results point out that the two small G proteins rhoA and rac-1 participate in cell sensitivity to mechanical strain and lead to the modulation of the Erk pathway. [source]

Magnetic Fingerprint Powder from a Mineral Indigenous to Thailand

JOURNAL OF FORENSIC SCIENCES, Issue 5 2010
Thatsanee Thonglon B.Sc.
Abstract:, A study was conducted to investigate whether natural magnetite (Fe3O4), which is an abundant mineral in Thailand, could be used as a magnetic powder in the detection of latent fingerprints. Because of the presence of impurities, powdered magnetite is only weakly attracted by a magnet and cannot be used as a magnetic fingerprint powder by itself. Mixing a small amount of magnetite powder with nickel powder greatly enhances the magnetic attraction. A mixture of magnetite powder and nickel powder in a mass ratio of approximately 1:100 was found to be suitable for use as a magnetic fingerprint powder. Fingerprints developed using the magnetite/nickel mixture on nonporous surfaces were found to exhibit good adherence and clarity. Using an automated fingerprint identification system, the number of minutiae detected in fingerprints developed by using the prepared powder on nonporous surfaces was found to be comparable to those detected in fingerprints developed by using a commercial black magnetic powder. The cost is lowered by more than 60%. [source]