The January 2009
issue contains the
the bulb,” speculating on the
forthcoming restrictions in the
use of incandescent lightbulbs in
many countries in
favor of compact
contend that compact fluorescents are a
mixed blessing, making one wonder
whether it is true that compact fluorescents:
• are manufactured using at least 10
times as much energy as that used in
making incandescent bulbs.
• contain poisonous mercury and
therefore have to be disposed of as
• produce electrosmog that is many
times greater than the TOC standard
for video screens (according to the
Swiss consumer magazine K-Tipp, No.
• produce an unnatural and inhomogeneous light spectrum with irritating
light flicker frequencies, many distinctive harmonics and strong blue pulse
• have a light output that greatly decreases in the course of their lifetime,
what with the number of switching actions.
More on IR in dentistry
I read the article in the February issue on
the use of infrared imaging in dentistry in
the UK (“Infrared Imaging Gives UK
Dentists a Better Look,” p. 60).
My group pioneered the development of
near-IR imaging of dental decay, and we
have published more than 15 papers on
near-IR imaging and the optical properties
of dental hard tissues in the near-IR, three
of which were published in Optics
Express, and we have the pending patent
We have developed both a low-cost system using CCD cameras at 830 nm and a
more expensive system that uses InGaAs
at 1300 nm. We have ongoing clinical
studies, and the NIH has funded our work
for the past six years.
Daniel Fried, PhD
University of California, San Francisco
Thank you for drawing this to our attention. The original piece was part of a report on the industry in Europe and therefore focused solely on companies and
institutions there. There was no intent to
overlook or undervalue the work of other
companies or countries.
Dr. Christine Connolly
Skepticism concerning black
I read David Shenkenberg’s article about
SiOnyx in the February 2009 issue (“Har-
vard Spinoff Company Takes on $200 Bil-
lion Global Market for Silicon,” p. 43).
Could you elaborate a bit concerning the