[R] Re: Info

[Andrea Calandra]

Sorry

I'm student in biomedical engineer and i have to solve this formula
for immuno-assay. I need to design a calibration curve

But i don't understand How can i write this formula in R language:
y = a + (c - a) /(1+ e[-b(x-m])

where
x = ln(analyte dose + 1)
y = the optical absorbance data
a = the curves top asymptote
b = the slope of the curve
c = the curves bottom asymptote
m = the curve X intercept

I have to calculate the parameters (a,b,c,m).After with X that i know
i calculate the Y.

> ==========================
> Date: Tue, 15 Jul 2003 19:30:31 -0700 (PDT)
> From: Rick Fletcher <fletcher at uidaho.edu>
> To: Andrea Calandra <a.CALANDRA at mclink.it>
> Subject: Re: Info
> ==========================
> 
> 
> Andrea, if you only have five data points, it will be very difficult 
> to
> fit all those parameters so they give a unique solution.  If 
> you want to
> fit all of your parameters at once, you need many more data points.
> 
> On Tue, 15 Jul 2003, Andrea Calandra wrote:
> 
> >  downloaded the R Language, it's very good!
> > but i have a question
> >
> > i have Five point with X and Y that know (concentration and 
> optical density) how can interpolate the curve
> > with folowing FIVE INTERPOLATION
> >
> > y = a + (c - a) /(1+ e[-b(x-m])
> > > >
> > > > where
> > > > x = ln(analyte dose + 1)
> > > > y = the optical absorbance data
> > > > a = the curves top asymptote
> > > > b = the slope of the curve
> > > > c = the curves bottom asymptote
> > > > m = the curve X intercept
> >
> >
> >
> >
> >
> >
> >
> > > ==========================
> > > Date: Mon, 07 Jul 2003 11:11:28 -0700 (PDT)
> > > From: Rick Fletcher <fletcher at uidaho.edu>
> > > To: Andrea Calandra <a.CALANDRA at mclink.it>
> > > Subject: Re: Info
> > > ==========================
> > >
> > > Did you find a solution yet?  I am sorry for the delay in 
> response,
> > > but
> > > the July 4th weekend is a big holiday here.  It is the day 
> we
> > > celebrate
> > > our independence from England.
> > >
> > > Do you still need help?
> > >
> > >
> > > On Fri, 4 Jul 2003, Andrea Calandra wrote:
> > >
> > > > i take your name on the web!
> > > > thank you
> > > >
> > > > > ==========================
> > > > > Date: Thu, 03 Jul 2003 11:05:24 -0700 (PDT)
> > > > > From: Rick Fletcher <fletcher at uidaho.edu>
> > > > > To: Andrea Calandra <a.CALANDRA at mclink.it>
> > > > > Subject: Re: Info
> > > > > ==========================
> > > > >
> > > > >
> > > > > Hello,
> > > > >
> > > > > May I ask how you got my name?  Thank you.
> > > > >
> > > > >
> > > > > On Thu, 3 Jul 2003, Andrea Calandra wrote:
> > > > >
> > > > > > HI
> > > > > >
> > > > > > I'm a student in chemical engineering at university 
> of
> > > Rome,
> > > > > and i have to implement an algoritm about FIVE PARAMETERS
> > > INTERPOLATION
> > > > > for a calibration curve (dose, optical density)
> > > > > >
> > > > > > y = a + (c - a) /(1+ e[-b(x-m])
> > > > > >
> > > > > > where
> > > > > > x = ln(analyte dose + 1)
> > > > > > y = the optical absorbance data
> > > > > > a = the curves top asymptote
> > > > > > b = the slope of the curve
> > > > > > c = the curves bottom asymptote
> > > > > > m = the curve X intercept
> > > > > >
> > > > > > Have you never seen this formula, because i don't fine
> > > information
> > > > > or
> > > > > > lecterature about solution of this!!!
> > > > > >
> > > > > > Can i help me
> > > > > > Andrea Calandra
> > > > > >
> > > > > > thank you
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > > Rick
> > > > > T. Rick Fletcher   -   http://www.chem.uidaho.edu/~fletcher/
> > > > > Associate professor of chemistry  |  That's Idaho, not 
> Iowa.
> > > > >    | ad hominem
> > > > > University of Idaho               |  Upper Left Hand 
> Corner.
> > > > >    | ad hominem
> > > > > Moscow, ID 83844-2343             |  No, I don't grow 
> potatoes.
> > > > > | ad hominem
> > > >
> > > >
> > > >
> > >
> > > Rick
> > > T. Rick Fletcher   -   http://www.chem.uidaho.edu/~fletcher/
> > > Associate professor of chemistry  |  That's Idaho, not Iowa.
> > >    | ad hominem
> > > University of Idaho               |  Upper Left Hand Corner.
> > >    | ad hominem
> > > Moscow, ID 83844-2343             |  No, I don't grow potatoes.
> > > | ad hominem
> >
> >
> >
> 
> Rick
> T. Rick Fletcher   -   http://www.chem.uidaho.edu/~fletcher/
> Associate professor of chemistry  |  That's Idaho, not Iowa. 
>    | ad hominem
> University of Idaho               |  Upper Left Hand Corner. 
>    | ad hominem
> Moscow, ID 83844-2343             |  No, I don't grow potatoes. 
> | ad hominem