Questions
Search help
Search fees
Account info
Help and feedback
Copyright information
Search NY Times
Search other papers
Obituaries
Death notices
Globe archives
Web reprints
Buy Globe photos
|
|
  
|
|
The article you requested is displayed below. [ Search again ]
SCIENCE BRIEFSAuthor(s): STEPHEN REUCROFT AND JOHN SWAIN Date: September 25, 2001 Page: C2 Section: Health ScienceSIT UP FOR STROKES YOU MAY BE ABLE TO REDUCE THE BRAIN DAMAGE YOU SUFFER IF YOU HAVE A STROKE JUST BY SITTING WITH YOUR HEAD UP. ANNE ROWAT OF EDINBURGH UNIVERSITY IN SCOTLAND AND HER COLLEAGUES LOOKED AT 129 STROKE VICTIMS IN FIVE DIFFERENT POSITIONS AND FOUND THAT SITTING UP GOT THE MOST OXYGEN TO THEIR BRAINS. THE EFFECT WAS QUITE LARGE, WITH 3 PERCENT MORE OXYGEN FOR PATIENTS SITTING UP OVER THOSE LYING DOWN. REF: NEW SCIENTIST, SEPT. 1, 2001 AND CEREBROVASCULAR DISEASES, VOL 12, NO. 1, 2001. NATURAL ANTIFREEZE ANTARCTIC FISH SURVIVE IN WATER FAR TOO COLD FOR NORMAL ANIMALS TO LIVE AND ARE IN CONSTANT DANGER OF FREEZING. TO ADAPT, THEY MAKE SPECIAL GLYCOPROTEINS THAT ACT AS ANTIFREEZE _ JUST THE SORT OF STUFF YOU MIGHT WANT TO PROTECT ORGANS FOR TRANSPLANTATION, OR TO GET PLANTS TO PRODUCE TO RENDER THEMSELVES FROST-RESISTANT. IT COULD EVEN HELP FROZEN FOOD AVOID FREEZER BURN. THE PROBLEM IS THAT THE NATURAL VERSION IS PRETTY UNSTABLE AND HARD TO EXTRACT, SO IT HASN'T FOUND MUCH APPLICATION BY ANYONE BUT THE FISH THEMSELVES. NOW ROBERT BEN AND HIS COLLEAGUES AT THE STATE UNIVERSITY OF NEW YORK IN BINGHAMTON HAVE MANAGED TO MAKE A MODIFIED VERSION THAT IS STABLE AND COULD BE SYNTHESIZED IN LARGE QUANTITIES, WHICH SHOULD LEAD TO A VIGOROUS RENEWAL OF INTEREST IN BIOLOGICAL ANTIFREEZES AND THEIR APPLICATIONS. REF: NEW SCIENTIST, AUG. 25, 2001. MINI METAL METTLE MATERIALS IN TINY GRAINS NEED NOT ACT THE SAME AS THEY DO IN BULK, AND CERTAINLY A SINGLE ATOM CAN'T BE EXPECTED TO ACT LIKE A GREAT LUMP, BUT HOW FAR DOWN DO YOU HAVE TO GO BEFORE MATERIAL STARTS BEHAVING DIFFERENTLY? DARCY HUGHES OF SANDIA NATIONAL LABORATORIES IN LIVERMORE, CALIF., AND NIELS HANSEN OF THE RISO LABORATORY IN ROSKILDE, DENMARK, HAVE BEEN STUDYING THE PATTERNS OF DAMAGE TO BLOCKS OF COPPER ON EVER-FINER SCALES. THEY FOUND THAT AT SCALES AS SMALL AS 3 BILLIONTHS OF A METER, THE STUFF STILL ACTS LIKE BULK METAL. THE WORK GIVES A LOT OF ENCOURAGEMENT TO NANOTECHNOLOGISTS WHO ARE TRYING TO MAKE EVER TINIER MACHINES. PREVIOUS WISDOM HAD SUGGESTED THAT WELL BEFORE THIS SCALE, SIMPLE PICTURES OF HOW METALS WOULD BEHAVE WOULD START TO BREAK DOWN. AS FAMED PHYSICIST RICHARD FEYNMAN HAD PREDICTED, ``THERE'S PLENTY OF ROOM AT THE BOTTOM!'' REF: PHYSICAL REVIEW LETTERS, SEPT. 24, 2001. BACKWARD OPTICS ALL NORMAL OPTICS, WHETHER MIRRORS, LENSES, OR GRATINGS, ARE BASED ON MANIPULATING BEAMS OF LIGHT BY THEIR INTERACTION WITH ELECTRONS IN MATTER. NOW IT LOOKS AS IF YOU CAN DO IT THE OTHER WAY AROUND. HERMAN BATELAAN AND HIS COLLEAGUES AT THE UNIVERSITY OF NEBRASKA HAVE SHOWN THAT A SUFFICIENTLY POWERFUL LASER BEAM CAN MAKE A PATTERN OF LIGHT THAT WILL DEFLECT BEAMS OF ELECTRONS. THE IDEA THAT THIS SORT OF THING MIGHT WORK HAD ALREADY BEEN PREDICTED IN 1933 BY PETER KAPITZA AND PAUL DIRAC, TWO OF THE MOST FAMOUS PHYSICISTS OF THE LAST CENTURY, BUT UNTIL NOW NOBODY HAD BEEN ABLE TO PULL IT OFF. THE WORK MAY LEAD TO NEW AND EXQUISITELY SENSITIVE DEVICES. REF: NATURE, SEPT. 13, 2001. LIGHT AND MOTIONS ONE OF THE MOST SENSITIVE WAYS TO DETECT TINY MOTIONS IS TO USE A DEVICE CALLED AN INTERFEROMETER, WHICH INTERFERES TWO BEAMS OF LIGHT WITH EACH OTHER TO MAKE PATTERNS OF LIGHT AND DARKNESS THAT SHIFT AS THE LENGTHS OF THE PATHS CHANGE. WHILE THESE THINGS CAN USUALLY MEASURE DIFFERENCES OF ABOUT HALF THE WAVELENGTH OF LIGHT, A NEW BREAKTHROUGH MAKES IT POSSIBLE TO DO VASTLY BETTER. YURI B. OVCHINNIKOV AND TILMAN PFAU AT THE UNIVERSITY OF STUTTGART IN GERMANY HAVE DEVELOPED WHAT THEY CALL A MULTIMODE WAVEGUIDE INTERFEROMETER, OR MWI. THE IDEA IS THAT INSTEAD OF INTERFERING TWO BEAMS, A SINGLE BEAM OF LIGHT ENTERS THE SPACE BETWEEN TWO MOVABLE PARALLEL MIRRORS. IT BOUNCES ABOUT IN A MYRIAD OF PATTERNS CALLED MODES, EACH OF WHICH CAN INTERFERE WITH ITSELF AND THE OTHERS AND AFFECT HOW MUCH LIGHT GETS THROUGH. THE RESULT IS A DEVICE THAT CAN DETECT MOTIONS OF JUST ONE-NINTH THE WAVELENGTH OF LIGHT, AND MAY BE ABLE TO GO DOWN TO A THOUSANDTH OF THE WAVELENGTH OF LIGHT. REF: PHYSICAL REVIEW LETTERS, SEPT. 17, 2001 EMPTY GESTURES QUANTUM MECHANICS LEADS TO SOME PRETTY STRANGE THINGS, AND HERE'S THE STRANGEST ONE WE'VE SEEN FOR A WHILE: EMPTY SPACES THAT PULL ON EMPTY SPACES. FOR A LONG TIME, PHYSICISTS HAVE KNOWN THAT TWO METAL PLATES SHOULD BE ATTRACTED TO EACH OTHER DUE TO THEIR EXCLUDING MORE AND MORE VACUUM FLUCTUATIONS OF THE ELECTROMAGNETIC FIELDS BETWEEN THEM AS THEY GET CLOSER - THIS IS THE SO-CALLED CASIMIR EFFECT, AND IT HAS BEEN BEAUTIFULLY CONFIRMED BY EXPERIMENT. NOW AUREL BULGAC OF THE UNIVERSITY OF WASHINGTON IN SEATTLE AND ANDREAS WIRZBA OF THE FORSCHUNGSZENTRUM JUELICH IN GERMANY HAVE SHOWN THAT SMALL EMPTY BALLS SURROUNDED BY A CONDUCTING MEDIUM (WHICH TAKES THE PLACE OF THE USUAL VACUUM IN THE CASMIR EFFECT) CAN BE EXPECTED TO EXERT SURPRISINGLY LARGE FORCES ON EACH OTHER. SEEING THIS EXPERIMENTALLY IS GOING TO BE TRICKY, BUT ONE IDEA IS TO USE BUCKY BALLS - SOCCER-BALL-SHAPED CARBON MOLECULES -TO PRODUCE EMPTY REGIONS IN LIQUID MERCURY. REF: PHYSICAL REVIEW LETTERS, SEPT. 17, 2001.
of The Boston Globe Online © Copyright 2001 Globe Newspaper Company
|