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Number 353, January 5, 1998 by Phillip F. Schewe and Ben Stein
FRACTAL PATTERNS INSIDE CELLS CAN REVEAL BREAST CANCER, scientists at the Mount Sinai School of Medicine have successfully shown (Andrew Einstein, 212-241-5851, einstein@msvax.mssm.edu). Pathologists must traditionally detect breast cancer through subjective means by studying individual cells from suspicious tissue and checking for abnormal-looking cell shapes and features. Analyzing images of actual breast cells, the Mount Sinai researchers have looked within the cell nucleus to study the distribution of chromatin, DNA-protein compounds which contain the chromosomes in a cell. Like many other biological structures in nature, chromatin forms a fractal pattern; that is, the arrangement of chromatin looks similar over a range of size scales. Applying their technique to cells from 41 patients (22 of whom were known to have breast cancer through independent means) the researchers correctly diagnosed 39 out of 41 cases (95.1% success rate) in a blind study. They did this by measuring differences in lacunarity (the largeness of gaps between chromatin regions in the nucleus) and by detecting differences in fractal dimension (which describes how fully a fractal object fills up the space that it occupies) between benign and malignant cells. (Einstein et al., Physical Review Letters, 12 Jan 1998.)
THE TOP PHYSICS STORIES OF 1997, according to the editors of Physics News Update, are as follows (in chronological order): Bose-Einstein condensation experiments show that two types of rubidium gases can be condensed in one atom trap and that part of a condensate can be extracted, constituting a sort of rudimentary atom laser; a black hole's event horizon is detected; electron-positron collisions at KEK (Japan) demonstrate experimentally that the electromagnetic coupling constant increases at very high q2, the square of the momentum transferred; hints that leptoquarks are produced at the HERA electron-proton collider in Germany; the Hipparcos satellite re-establishes many star distances; many new properties for carbon nanotubes; first movies of single DNA replicating; force detection with atto-newton precision with combined AFM and MRI techniques; Comet Hale-Bopp; superfluid analog of a Josephson junction; 100th anniversary of the discovery of the electron; excited state of an atom has a 10- year lifetime; gamma ray bursters are extragalactic; proton pairs ejected from nuclei; the Mars Pathfinder and Mars Surveyor missions; evidence of a 4-quark meson at Brookhaven; fractionally charged quasiparticles in a quantum Hall experiment; real (not just virtual) photons create matter; most intense manmade sound produced; quantum teleportation demonstrated (350);50th anniversary of transistors.
PHYSICS DEMOGRAPHICS. A variety of reports issued regularly by the AIP Education and Employment Statistics Division (stats@aip.acp.org) provides an ongoing detailed picture of the US physics community. Here are some recent highlights. In the 1995/96 academic year 12,596 graduate students pursued physics degrees at 262 academic departments; the male-to- female ratio: 84/16; the US to non-US citizen ratio: 57/43 (1996 Graduate Student Report; Sept. 1997). In 1995, women accounted for 12% of new physics PhDs and 17% of new bachelor's and master's degree recipients (1996 Employment Follow-up of 1995 Physics Degree Recipients; July 1997). Physics bachelor's degrees in 1996 numbered 4173, the lowest level since the 1950s (1996 Bachelor's Degree Recipients; June 1997).
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