What is SVEDBERG?
SVEDBERG is a Windows program for whole-boundary analysis of sedimentation velocity data. It fits directly to the raw scans (usually spanning the entire run) to derive the sedimentation coefficient and molar mass (or, if you prefer, sedimentation coefficient and diffusion coefficient) for up to 6 independent species (mixtures of up to 6 components).
The program is designed to be easy to use, even for novices, yet it also offers many options for the 'power user' when they are needed. It uses multi-page analysis 'documents' and a familiar user interface with toolbars and buttons, making it similar to other Windows programs to reduce the learning curve. It also incorporates a number of intelligent 'wizards' that automatically accomplish tasks such as locating the meniscus position, removal of systematic noise ("jitter") and fringe jumps from interference scans, and even making reasonable initial guesses for the molecular parameters.
This is not a package that tries to do everything---its purpose is to implement one particular approach (analysis of single species and mixtures), do that very well and very easily, and do it in a highly reproducible and well-documented manner. It is not intended to be able to handle samples where the data is strongly influenced by dynamic reversible-association reactions (interacting boundaries). However when reversible interactions are strong enough that a reversible oligomer or complex can be treated as a single species then SVEDBERG is quite useful for identifying the molar mass (stoichiometry) of that species, which in turn can be a very useful input to analysis of data using other software acquired under conditions where the dynamic interactions are more significant.
The success of this approach is demonstrated by its use in 140+ known publications. More significantly, many of these are from intermittent or casual users of AUC, proving you don't have to devote years to learning data analysis to successfully answer important research questions with SV.
The program is now distributed as "freeware" and requires no registration. The only restriction is that it cannot be sold or packaged with other commercial software. The author asks only that you cite it properly when publishing your analyzed results.
How does SVEDBERG differ from the multi-component models in Peter Schuck's SEDFIT?
SEDFIT is an excellent program with many strengths. It's 'non-interacting discrete species' model is essentially equivalent to the model used in SVEDBERG, except it derives the theoretical fits via finite-element numerical methods rather than approximate analytical functions. Both approaches can give an accuracy of better than 1% for hydrodynamic properties, i.e. more than sufficient for any real experiment.
The analytical function approach used in SVEDBERG is faster to compute and its Gauss-Newton fitting algorithm often converges more rapidly (especially when many components are present) than the algorithms available in SEDFIT. Thus overall SVEDBERG is generally faster and easier to use, and can successfully converge on multi-species fits in situations where SEDFIT fails to converge on a solution.
Perhaps more significantly, SVEDBERG always gives error estimates for all the fitted parameters, and can derive robust confidence limits for all parameters when desired. SEDFIT never gives error estimates or true confidence limits for concentration or species fractions, and can only derive confidence limits for s or M for a single component and through a lengthy procedure.
Another key difference is that SVEDBERG provides comprehensive, well-formatted printed reports that completely document the analysis, and which can be pasted into a word processor or electronic lab notebook. SEDFIT has no reporting capability.
SVEDBERG saves all data and parameters into a single file that can be quickly restored. SEDFIT has an incomplete ability to restore all aspects of previous analyses, making it difficult to reproduce what you have done.
Some other advantages of SVEDBERG over SEDFIT:
Some advantages of SEDFIT over SVEDBERG:
SVEDBERG 7 runs under Windows 98, NT, 2000, XP, Vista, or Windows 7. Use via Windows dual-boot configurations on MacIntosh systems is neither supported nor guaranteed.
This program also requires the Microsoft .NET framework to be present on the computer. This is often already true for newer computers. If it is not already present, this is detected during installation and a link is given so it can be downloaded from Microsoft and installed.
Although SVEDBERG will run correctly at a 640x480 (VGA) video resolution, a resolution of 1024 x 768 or higher is highly recommended.
Program installation requires approximately 11 MBytes of disk space (most of
which is for the comprehensive Help file).