From: John Philo <jphilo@mailway.com>
  To  : Rasmb <rasmb@alpha.bbri.org>
  Date: Mon, 26 Jul 1999 19:07:09 -0700

release of program DCDT+

A new shareware sedimentation velocity analysis program, DCDT+, is now
available (a Windows 3.1/95/98 program).

The complete description may be found at
http:/jphilo.mailway.com/dcdtplus.html so I will only mention a few
things here.

Briefly, this program integrates an implementation of Walt Stafford's
DCDT algorithms with non-linear least squares fitting for mixtures
containing up to 5 species, using an interface similar to that used in
SVEDBERG.

Unlike the Beckman software, it CORRECTLY derives diffusion
coefficients or molecular masses through fitting of g(s*) curves (the
Beckman software contains errors), it gives confidence intervals for
the derived parameters, and it weights the data points according to
their uncertainties.

DCDT+ uniquely allows fitting to the dc/dt data rather than g(s*) for
further improvements in accuracy and ability to resolve multiple
components.

Another important feature is that it quickly tells you when you are
including too many scans in the analysis and broadening the
distributions, without guessing or struggling with manual computations
to implement Walt Stafford's "rule of thumb".

DCDT+ also incorporates correction of the raw sedimentation
coefficients in the distributions, and the results from fitting, to
s(20,w) values so the results are ready for publication.

Lastly, it has a true Help file with a searchable index, which is
linked to the program to call up Help for the part of program on which
you are working, and which also contains step-by-step tutorials,
"how-to" guides, and FAQs.

DCDT+ may be downloaded for a 30-day trial via the web address given
above.

John Philo