Hi, Nick,
It works and significantly decreased the objective function value, which
is consistent with the results from Hempel et al.
Thank you very much!
Kind Regards, Ying
Nick Holford wrote:
Ying,
If you assign the ETA to a variable outside $DES then you can use the variable
in $DES e.g.
$PK
ETAT=ETA() ; ETA for random effect on offset in cycle
$DES
DPS2 = (KOUT*A1 + B1*DPI/12)*DCOS(DPI*(T+ETAT)/12)
I would also suggest putting DPI = 3.14159 in $PK. There is no need to do this
assignment every time the differential equation solver is called.
Nick
Ying HONG wrote:
Dear NM users,
A biomarker, which shows clear circadian rhythm during placebo
treatment, was described by a turnover model with the introduction of a
periodic time-dependent production function KST with two harmonics. The
code in $DES is written as follows:
$DES
DPI = 3.14159
DPS1 = KOUT*A0
DPS2 = (KOUT*A1 + B1*DPI/12)*DCOS(DPI*T/12)
DPS3 = (KOUT*B1 - A1*DPI/12)*DSIN(DPI*T/12)
DPS4 = (KOUT*A2 + B2*DPI/6) *DCOS(DPI*T/6)
DPS5 = (KOUT*B2 - A2*DPI/6) *DSIN(DPI*T/6)
KST = DPS1 + DPS2 + DPS3 + DPS4 + DPS5
DADT(1) = KST - KOUT*A(1)
In the paper published by Hempel et al (CPT, 1998;64:622-35), a ETA was
introduced in the time T which accounts for the differences in wake-up
times between subjects (e.g. DCOS(DPI*(T+ETA)/12). Because ETA is
prohibited in the $DES, how can I code the interindividual variability
of time in the control stream?
Any suggestion is highly appreciated!
Kind Regards, Ying
--
Ying HONG, PhD
Department of Pharmaceutical Sciences
University at Buffalo, SUNY
C237 Cooke Hall, Buffalo, NY 14260
Tel: 716 645 2828 ext 275
Fax: 716 645 3693
E-mail: [EMAIL PROTECTED]
--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand
email:[EMAIL PROTECTED] tel:+64(9)373-7599x86730 fax:373-7556
http://www.health.auckland.ac.nz/pharmacology/staff/nholford/
--
Ying HONG, PhD
Department of Pharmaceutical Sciences
University at Buffalo, SUNY
C237 Cooke Hall, Buffalo, NY 14260
Tel: 716 645 2828 ext 275
Fax: 716 645 3693
E-mail: [EMAIL PROTECTED]
