Note: the absence of SVEDBERG program updates for several years does not mean program development has halted. This simply reflects the fact that no bugs have been reported since the last update! A major revision will be released first quarter 2012, including a user interface similar to that in DCDT+ version 2.
What is SVEDBERG?
SVEDBERG is a Windows program for analysis of sedimentation velocity data. It fits directly to either absorbance or interference scans to derive the sedimentation and diffusion coefficients (or, if you prefer, sedimentation coefficient and molecular mass) for up to 4 independent species.It is designed to be quick and easy to use, yet to give robust results. Many users find that they can finish the analysis of one sample before the centrifuge rotor has stopped spinning! It has a comprehensive, context-sensitive Help system and on-line manual to guide the user. It is being used in over 50 labs around the world (partial list here). It has been used to analyze data for more than 130 known publications.
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How is it different than other velocity analysis programs?
SVEDBERG is particular good at accurate quantitative results and at resolving properties of minor species present in low amounts (e.g. 5% of a dimer).SVEDBERG uses "intelligent file loading" to make it easy to load a series of scan files for analysis, and allows you to quickly see the properties of each scan or remove unwanted scans without starting over.
For multi-species fits SVEDBERG also allows the user to constrain the properties of the species with respect to one another, forcing the constrained species to have hydrodynamic properties which are in ratios appropriate for small oligomers. These constraints can significantly enhance the ability to resolve minor species (and also the accuracy of the results for the major species).
SVEDBERG also helps you to document and reproduce your analyses by printing complete reports listing exactly what data were fitted and all parameters which affect the results, and by saving all data and parameters in a single binary data file so you can instantly reload an entire analysis.
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 1% or better for hydrodynamic properties, i.e. more than sufficient for any real experiment. The analytical function approach used in SVEDBERG is faster to compute and allows the use of a Gauss-Newton fitting algorithm that converges more rapidly (especially when many components are present) than the simplex algorithm used 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, whereas SEDFIT 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 printed reports that completely document the analysis and saves all data and parameters into a single file that can be quickly restored. SEDFIT has no reporting capability and an incomplete ability to restore all aspects of previous analyses, making it difficult to reproduce or document what you have done.
Some other advantages of SVEDBERG over SEDFIT:
 | for multi-species fits the relative masses or sedimentation coefficients can be constrained to values appropriate for a series of oligomers |
| true context-sensitive, indexed and searchable HELP file |
| accurate, easy, and reproducible setting of meniscus position and data fitting limits |
| superior graphs that can be printed, exported or saved to disk, with full graph scaling and customization capabilities |
| handles conversions of raw s and D values to s20,w and D20,w |
| superior ease-of-use |
Some advantages of SEDFIT over SVEDBERG:
| models for associating systems and non-ideal sedimentation |
| can use data near base of cell where solutes accumulate |
| works with very low mass species such as peptides |
| does floatation analysis as well as sedimentation |
What does SVEDBERG cost?
To continue using this program after the 30-day trial period, or to publish results of analyses run during the trial period, you must purchase a software license for $500 (discounted to $250 for academic and non-profit institutions).This fee primarily covers the cost of supporting and distributing the program; it would need to be an order of magnitude higher to cover the thousands of hours that went into program and Help file development.
This is a "site" license and users may run the program on multiple computers at a single site. For academic/non-profit licenses "site" means a single laboratory or a single Facility. Analytical centrifuges housed in more than one department or building of a university, or under the control of independent principal investigators, by definition represent different 'sites' and therefore each of those sites must purchase its own license. For users in industry a "site" is by definition a single analytical centrifuge, and companies are expected to buy a license for each centrifuge.
Registered users will receive support for their questions, free updates, and quick fixes for any bugs they find. To date all bugs have been fixed in 1 month or less (and often in less than a week). Don't you wish you could say the same about the other software you use?
Why isn't SVEDBERG distributed for free like some other AUC software packages?
Programs such as SEDFIT and ULTRASCAN were developed and are supported using government funds; approximately $1 million in tax dollars have been spent on developing and supporting those programs, to mention just two of many. No government or grant funds have been used in developing SVEDBERG, and none are available for providing user support. Distribution of SVEDBERG is paid for by its users, and the total income from program licenses represents ~1% of what has been spent on developing "free" programs.
The essence of the shareware concept is to provide you with software that you can "try before you buy", while (at least partially) compensating the developers time, effort, and expenses to create and support the program. Taxpayers had no choice about whether to pay for the "free" AUC programs, but you do have a choice. If after your free trial you don't think SVEDBERG is worth paying for, then simply don't use it.
Ordering information
There is no difference between the "trial" and "registered" versions of the program---registered users are supplied a serial number which removes the 30-day restriction and also allows the start-up "splash screen" to be bypassed.
Detailed information about payment by check or purchase order, and placing credit card orders by phone or the Internet, is contained here and in the program Help file.
The program is only available electronically by downloading (although users who wish to purchase a CD-ROM containing the downloadable installation file may do so when they order a license via credit card through NorthStar solutions).
System Requirements
SVEDBERG version 6 will run under Windows® 3.1, 95, 98, NT, 2000, or XP or 32-bit versions of Windows Vista and Windows 7 (but please note that the impending update will no longer support Windows 3.1 or 95). It does not run under Asian-language versions of Windows 95 or 98. It is also reported not to run under Windows® emulation on MacIntosh and IMac systems, and operation under such environments is neither supported nor guaranteed.Although SVEDBERG will run correctly at a 640x480 (VGA) video resolution, a resolution of 800x600 or higher is highly recommended.
The program requires approximately 2.4
MBytes of disk space.