Fp Values Research Articles

Fluid-to-particle Heat Transfer Coefficients for Continuous Flow of Suspensions in Coiled Tube and Straight Tube with Bends

Fluid-to-particle heat transfer coefficient (h fp ) for spherical particles in continuously flowing food suspensions (0–30% v/v green peas in 1.5% sodium carboxymethylcellulose solution) in the holding section of an aseptic processing system was determined. The effects of hold tube geometry, temperature, flow rate, and particle concentration were investigated. The h fp values ranged from 538 to 1450 W/m 2·°C in the coiled tube and from 204 to 1220 W/m 2·°C in the straight tube. Significantly, higher h fp value was observed for particles in the coiled tube as compared to that in the straight tube. The h fp value increased with temperature, flow rate, and particle concentration. Dimensionless correlations relating the Nusselt number to Reynolds and Prandtl numbers were developed. Estimation of h fp values based on the particle resistance temperature device (RTD) data and dimensionless correlations indicated a reduction in the degree of overprocessing of average particles when a coiled tube was used instead of a straight tube for the holding section.

Evaluation of factors influencing tube-flow fluid-to-particle heat transfer coefficient using a calorimetric technique

A previously developed calorimetric technique involving bulk or mass average temperature measurement of a moving particle without interfering in its motion was used to evaluate the effect of fluid flow rate, viscosity and temperature as well as particle size on the associated fluid-to-particle heat transfer coefficient ( h fp) under tube-flow condition. Experiments were carried out for different flow rates (9–19 l/min), concentrations of carboxymethyl cellulose (CMC) in the carrier fluid (0–1% CMC solution) and temperature (50–70°C) as well as particle size (19–25.4 mm). The results of over 300 experiments indicated that the h fp values, which ranged from 650 to 2660 W/m 2 K depending on the experimental conditions, increased significantly with an increase in fluid flow rate and particle size, and decreased with CMC concentration and temperature. A dimensionless correlation obtained between Nusselt number and a group of other dimensionless numbers yielded a high R 2 value of 0.97 demonstrating an excellent suitability for the conditions tested.

Impact of Doppler guidewire size and flow rates on intravascular velocity profiles.

Coronary blood flow velocity measurements by conventional intravascular catheter-based Doppler devices are well known to be affected by catheter size. Moreover, it is of clinical importance that the assessment of maximum vasodilator capacity, i.e., the coronary reserve, might be considerably affected by a shape change of the velocity profile under hyperemia. Therefore, the present in vitro study aimed to assess the impact of a small-size Doppler guidewire on the velocity profiles interrogated in tubes with diameters corresponding to the epicardial coronary arteries at clinically relevant flow rates. A 0.014" guidewire was inserted into four serially connected silicone tubes of known diameter, which were perfused with discarded human whole blood by means of a roller pump. In order to determine the effect of the Doppler guidewire on the velocity profile antegrade and retrograde perfusion were carried out in each vessel segment. Vm, the true mean velocity, was calculated from the time collected flow divided by the corresponding vessel cross-sectional area. Average peak velocity (APV) measurements were obtained by pulling back the Doppler device across each of the four vessel segments with given flow rates ranging from 1.14-5.88 ml/s in antegrade and retrograde direction. The shape factor of the recorded velocity profile (fp) is defined as vm/APV and is generally assumed to be close to 0.5. Antegrade perfusion: APV = 1.63 vm + 5.35 (R2 = 0.98); fp = 0.001 vm + 0.51. Retrograde perfusion: APV = 1.71 vm + 3.33 (R2 = 0.98); fp = 0.001 vm + 0.52. Due to the constant relationship between APV and vm, velocity profiles within vessels of epicardial coronary artery size are not substantially disturbed by the presence of the Doppler guidewire. The slight, but significant increase of experimental fp with increasing flow is at variance with the theoretically expected fp values.

Intracellular Hemoglobin S Polymerization and the Clinical Severity of Sickle Cell Anemia

AbstractRecent work has enabled us to quantitate the four variables (2,3-DPG concentration, pHi, non-S hemoglobin composition, and O2 saturation) that modulate the equilibrium solubility (csat) of Hb S inside sickle erythrocytes (SS RBCs). Using measured values of mean corpuscular hemoglobin concentration (MCHC), 2,3-DPG concentration, and %Hb (F+A2), along with estimates of pHiand the Δcsat due to partial oxygenation of SS RBCs in the microcirculation, we calculated the mean polymer fraction (fp) in erythrocytes from 46 SS homozygotes. Values of fp derived from the conservation of mass equation ranged from 0.30 to 0.59. MCHC and %Hb F were major determinants of the magnitude of fp; 2,3-DPG concentration and pHialso contributed, but to a lesser extent. A clinical severity score (CSS) was assigned to each patient based on mean hospitalization rate. There was a weak, but statistically significant, negative correlation between fp and steady state hematocrit (P = .017), but none between fp and whole blood hemoglobin concentration (P = .218). Although there was no correlation between fp and mean number of hospitalization days per year, patients with the greatest number of admissions and hospitalization days were found only among those who had an fp > 0.45. All five patients who died during the follow-up period (median, 7 years; range, 3 to 10 years) had fp values ≥0.48. However, patients with few admissions, low hospitalization days, and long survivals occurred at all fp levels. These results suggest that the clinical course of homozygous SS disease cannot be predicted by mean fpcalculations, which assume a homogeneous distribution of the five variables that modulate intraerythrocytic polymerization. A heterogeneous distribution is more likely; so the amount of polymerized Hb S could vary considerably among cell populations. Factors such as membrane abnormalities and endothelial cell interactions may also contribute to clinical severity.

Intracellular Hemoglobin S Polymerization and the Clinical Severity of Sickle Cell Anemia

Recent work has enabled us to quantitate the four variables (2,3-DPG concentration, pHi, non-S hemoglobin composition, and O2 saturation) that modulate the equilibrium solubility (csat) of Hb S inside sickle erythrocytes (SS RBCs). Using measured values of mean corpuscular hemoglobin concentration (MCHC), 2,3-DPG concentration, and %Hb (F+A2), along with estimates of pHiand the Δcsat due to partial oxygenation of SS RBCs in the microcirculation, we calculated the mean polymer fraction (fp) in erythrocytes from 46 SS homozygotes. Values of fp derived from the conservation of mass equation ranged from 0.30 to 0.59. MCHC and %Hb F were major determinants of the magnitude of fp; 2,3-DPG concentration and pHialso contributed, but to a lesser extent. A clinical severity score (CSS) was assigned to each patient based on mean hospitalization rate. There was a weak, but statistically significant, negative correlation between fp and steady state hematocrit (P = .017), but none between fp and whole blood hemoglobin concentration (P = .218). Although there was no correlation between fp and mean number of hospitalization days per year, patients with the greatest number of admissions and hospitalization days were found only among those who had an fp > 0.45. All five patients who died during the follow-up period (median, 7 years; range, 3 to 10 years) had fp values ≥0.48. However, patients with few admissions, low hospitalization days, and long survivals occurred at all fp levels. These results suggest that the clinical course of homozygous SS disease cannot be predicted by mean fpcalculations, which assume a homogeneous distribution of the five variables that modulate intraerythrocytic polymerization. A heterogeneous distribution is more likely; so the amount of polymerized Hb S could vary considerably among cell populations. Factors such as membrane abnormalities and endothelial cell interactions may also contribute to clinical severity.

Laser scanning cytometry distinguishes lymphocytes, monocytes, and granulocytes by differences in their chromatin structure

By providing rapid measurements of cellular fluorescence in addition to morphometric analysis, the novel microscope-based multiparameter laser scanning cytometer (LSC) combines advantages of flow and image cytometry. Analysis of the integrated fluorescence intensity (IF) versus peak fluorescence intensity (maximal fluorescence per pixel; FP) versus fluorescence area (FA) of the cells stained with the DNA intercalating fluorochrome propidium iodide (PI) made it possible to discriminate lymphocytes, monocytes, and granulocytes in samples of peripheral blood of normal individuals. Lymphocytes, characterized by maximally condensed chromatin, had the highest FP and lowest values of FA. Granulocytes had the lowest FP and the highest FA. They also had increased IF compared to lymphocytes and monocytes. The difference in IF between granulocytes and monocytes/lymphocytes was abolished after exposure of cells to 0.1 M HCl at 0-4 degrees C, which is known to dissociate histones from DNA in chromatin. Monocytes were characterized by intermediate values of peak and area fluorescence intensity compared to lymphocytes and granulocytes. Thus, although all three classes of white blood cells have the same DNA content, they can be distinguished based on differences in structure of their chromatin after staining with PI. Discrimination of these cells by LSC is similar to that provided by flow cytometry based on differences in forward and side light scatter properties.

Endodermal sinus tumor of the ovary in pregnancy

The ultrasonographic evidence of an irregular mixed mass, cystic and solid, in retrouterine area and the high levels of alpha(1)-FP values in a young pregnant woman, indicated the possibility of an ovarian germ cell neoplasia. Respecting the patient's will, pregnancy was protracted until the 36th week. A cesarian section allowed the releasing of a vital fetus and the removal of a neoplastic mass which proved to be an endodermal sinus tumor (EST) at stage Ia. Then the patient, the 12th case of EST in pregnancy reported in the literature, underwent 5 PVB chemotherapy cycles and, 3 years after the intervention, appears disease-free.

Critical current density and flux pinning in Y1?x Ho x Ba2Cu3O7?? epitaxial films

The critical current densityJc of Y1−xHo x Ba2Cu3O7−δ (YHBCO) epitaxial thin films withx=0, 0.2, 0.4, 0.7 at various temperatures and magnetic fields has been measured magnetically. TheJc and flux pinning density Fp values are significantly enhanced with the Ho substitute amountx with the optimal effect achieved at Ho concentration around x=0.4 in the entire measured temperature (30–77 K) and magnetic field (0–3 T) ranges. X-ray diffraction patterns have shown that the greater the lattice deformation, the higher theJc of the films.

Seasonal changes in chlorophyll fluorescence of white spruce seedlings from different latitudes in relation to gas exchange and winter storability

Variable chlorophyll fluorescence (Fvar) was investigated as a tool in detection of distinct seasonal physiological changes in 1+0 intact white spruce seedlings. The loss of the characteristic Fvar peak (Fp) between 0.8 and 1.0 s after illumination of dark adapted seedlings is an indication of regulation of photosynthetic activity in August. The peak represents excess photochemical water-splitting of photosystem II. We interpret its loss as a physiological indicator of the process of dormancy induction. Three dimensional (i.e. X[0-300 s], Y[rfu], Z[time of year] axis) Fvar curves of non-stressed seedlings measured over 300 s followed a three phase change over the growing season. In actively growing seedlings, the portion of the Kautsky induction curve between 60 and 300 s was 0.4 relative fluorescence units (rfu) in northern (i.e. >56° latitude) seedlots and 0.6 in the southern (i.e. <56° latitude) range seedlot from August until early September. About mid-September curve features between 60 and 300 s decreased sharply to approximately zero (rhu) by October. Freeze test data indicated seedlings became frost hardy during this time. The third, or inactive phase was seen as flat line from 40 to 100 s. The portion of the curve after 100 s was responsive to short term temperature changes. White spruce seedlots of northern and southern B.C. latitudes having curve fluorescence peak (Fp) values at about 1 s of 0.6, and 0.8 (rhu) respectively, plus curve minimum (Fmin) values at about 60 s which do not decrease further over a 2–3 week period represent stock which can safely be lifted for cold storage. The Fvar attribute at 5 s after the actinic light is turned on (F5s) correlates well with net photosynthesis (r2 =0.61) during the growing season.

Influence of particle characteristics on fluid-to-particle heat transfer coefficient in a pilot scale holding tube simulator

Fluid-to-particle convective heat transfer coefficients ( h fp) were estimated for spherical and finite cylindrical particles resident in the holding tube of a pilot scale aseptic processing simulator. Experiments were conducted using both Newtonian and non-Newtonian carrier fluids at 100 and 110 °C. Average h fp values ranged from 60 to 1000 W/m 2C, depending on operating conditions of fluid concentration, temperature, flow rate, particle size, shape and particle orientation in the holding tube. The corresponding Biot numbers ranged from 6 to 60. With the exception of particle length and its orientation, which had no significant impact ( P > 0.05) on the heat transfer coefficient, all other parameters had significant influences ( P < 0.05) on h fp. Spherical particles had higher h fp values compared with finite cylinders of approximately the same diameter under similar experimental conditions. Contrary to reported trends, the heat transfer coefficient was found to increase with decreasing particle size under all experimental conditions studied. The effect of particle-to-tube diameter ratio on h fp was not clear cut.

Liquid-to-particle convective heat transfer in non-Newtonian carrier medium during continuous tube flow

Liquid-to-particle convective heat transfer coefficients (h fp) were determined in non-Newtonian carriers during continuous flow using three different experimental techniques. Process parameters such as carrier viscosity, flow rate, particle size, and radial location were found to influence h fp values. Minimum and maximum values of h fp were found to be 363 W/m 2 °C and 2010 W/m 2 °C respectively over a fluid Reynolds number range of 14·5 to 798. Significant fluid-particle relative velocities (0·02 to 0·19 m/s) were measured during visualization studies of fluid flow around a moving particle. The relative velocity and consequently h fp values were influenced by particle radial location and the local flow field about the particle.

Heat transfer between fluid and particles in aseptic processing

The particle heat transfer coefficient, h fp , is one of the critical factors, besides the residence time distribution, that has to be known for the design and development of continuous heat processes of particulate food products. In the present work, data and methods for determining h hp for conditions relevant to aseptic processing have been studied. The influence of product characteristics, such as size and composition of particles, fluid properties, temperature differences and fluid motion, have been investigated. Among the parameters investigated, the flow field around the particles was shown to be the most important for heat transfer but for special conditions the particle size, particle shape or thermal properties of the particle, as well as the apparent viscosity and the thermal properties of the fluid, are equally important for the value of h fp . For safety considerations, the present investigation indicates that h fp values corresponding to an Nu value of 5–6 should be relevant for medium-sized spherical particles transported by a highly viscous liquid. For the quality aspects, different conditions have to be considered. Particles at different positions in·the tube flow will experience different heat transfer. The few particles in the centre of the tube will experience a low heat transfer and h fp values corresponding to Nu values ranging between 5 and 10. The larger amounts of particles are transported in the liquid with a pronounced velocity gradient which yields Nu values of 10–17, while for extreme conditions occurring for sedimented particles, Nu values between 20 and 45 could be expected.

Fecal progestagen evaluations to monitor the estrous cycle and pregnancy in the okapi (Okapia johnstoni)

AbstractThe present study was conducted to establish a noninvasive method of reproductive monitoring in the okapi (Okapia johnstoni). Fecal samples were collected three times a week from nonpregnant okapis (n = 3) for periods of 2, 9, and 23 months, respectively, and for 2 months each from pregnant okapis (n = 4) at different stages of gestation. Samples were analyzed with an enzyme‐immunoas‐say (EIA), using an antibody against pregnanediol, and the results are considered as measurements of unconjugated total immunoreactive progestagens (Pd‐Pgs). Mean values of Pd‐Pgs during the follicular (FP) and the luteal phases (LP) of the estrous cycles were 0.6 ± 0.1 μg/g and 6.1 −0.3 μg/g feces, respectively. Matings occurred at the terminations of the LP. By dividing the number of entire LPs into the time over which samples were available, average estrous cycle lengths in two okapis were estimated to be 15.5 (n = 11 LP) and 15.8 (n = 36 LP) days, respectively. In three animals, gestation lengths of 423, 424, and 431 days were calculated by observed matings. During days ‐280 to ‐220 before parturition, the fecal Pd‐Pgs constantly increased from about 20‐‐60 μg/g fecès. Values were 100‐‐350 μg/g during the last third of gestation. Values decreased in the week before parturition, and a continuous decline to FP values was observed within 3‐‐4 days postpartum. During the 2 months postpartum investigated in one animal, the Pd‐Pgs were in the FP range except one LP 3 weeks postpartum. It was concluded that fecal Pd‐Pgs in female okapis are present in a ratio of ∼1: 10:&gt;100 during FP, LP, and late pregnancy, respectively. Their measurement by EIA enables noninvasive monitoring of the estrous cycle and pregnancy diagnosis. © 1993 Wiley‐Liss, Inc.

Fetal lung maturity evaluation with fluorescence polarization of the amniotic fluid.

Fluorescence polarization of the amniotic fluid from 39 high risk pregnancies requiring preterm delivery was measured in order to assess the maturity of the fetal lung. The study population included 15 cases of intrauterine growth retardation, ten maternal hypertension, five maternal Hodgkin's disease, three placenta previa, two fetal malformation, two polyamnios, one untreated diabetes, one maternal nephropathy. All patients underwent a single amniocentesis before deciding whether to deliver a preterm baby and FP of the amniotic fluid was done within two hours from amniocentesis. In five cases this was > 0.311, the cut-off limit taken as an indicator of fetal pulmonary status, and three of these developed respiratory distress syndrome. In 34 cases FP values were < or = 0.311; in spite of the apparent lung maturity two of these newborns developed respiratory distress syndrome. On the basis of these results the FP sensitivity was calculated as 60%, specificity 94% and the overall accuracy 90%.

Distribution kinetics of FK-506, a novel immunosuppressant, after intravenous administration to rats in comparison with cyclosporin A

The distribution kinetics of a novel potent immunosuppressant, FK-506 (FK) has been studied in comparison with cyclosporin A (CyA) both in vivo and in vitro using blood specimens. The infusion studies on FK, 5.0 mg kg-1 through the portal and femoral veins showed that the mean hepatic extraction ratio of FK was 27.9 per cent. The effect of clamping both the hepatic artery and the portal vein on the plasma disappearance profiles of FK, 5.0 mg kg-1, and CyA, 3.5 mg kg-1 was studied. The plasma disposition kinetics of CyA was almost the same as in the normal rats. However, the plasma FK levels were about 10 times higher than those obtained in the control group rats. This difference is attributed to the restricted initial distribution of FK to the liver, because the volume of the initial distribution space, V1, of FK was about 10 times smaller than that obtained in normal rats. In in vitro experiments, drug distribution was studied in blood samples (2.0 ml) spiked with FK or CyA, 1.0 micrograms ml-1. The plasma drug levels measured at 2 min after drug administration were 0.842 +/- 0.012 micrograms ml-1 and 0.769 +/- 0.047 micrograms ml-1 for FK and CyA, respectively. The distribution volume in the blood compartment, VB, was determined by dividing the spiked amount of drugs with these plasma concentrations. The VB was 2.38 +/- 0.04 ml for FK and 2.62 +/- 0.16 ml for CyA. There was no significant difference in VB between FK and CyA. The plasma free fraction, fp of the drugs was measured by the equilibrium dialysis method. For FK, the mean fp values (+/- SE) were 1.31 +/- 0.18 per cent (2.0 micrograms ml-1) and 1.93 +/- 0.18 per cent (5.0 micrograms ml-1). For CyA, the fp values were 4.85 +/- 0.36 per cent (1.0 micrograms ml-1) and 5.75 +/- 0.82 per cent (5.0 micrograms ml-1). The hydrophobicity parameter, logP' determined through the HPLC method was 0.386 for FK and 0.545 for CyA. Although FK was less hydrophobic than CyA, its protein binding was higher than CyA.

A HADRON–QUARK VERTEX FUNCTION: INTERCONNECTION BETWEEN 3D AND 4D WAVE FUNCTIONS

The interrelation between the 4D and 3D forms of the Bethe–Salpeter equation (BSE) with a kernel [Formula: see text] which depends on the relative four-momenta, [Formula: see text] orthogonal to Pμ is exploited to obtain a hadron–quark vertex function of the Lorentz-invariant form [Formula: see text]. The denominator function [Formula: see text] is universal and controls the 3D BSE, which provides the mass spectra with the eigenfunctions [Formula: see text]. The vertex function, directly related to the 4D wave function Ψ which satisfies a corresponding BSE, defines a natural off-shell extension over the whole of four-momentum space, and provides the basis for the evaluation of transition amplitudes via appropriate quark-loop digrams. The key role of the quantity [Formula: see text] in this formalism is clarified in relation to earlier approaches, in which the applications of this quantity had mostly been limited to the mass shell (q · P = 0). Two applications (fP values for [Formula: see text] and Fπ for π0 → γγ) are sketched as illustrations of this formalism, and attention is drawn to the problem of complex amplitudes for bigger quark loops with more hadrons, together with the role of the [Formula: see text] function in overcoming this problem.

藻類のリン摂取と増殖に関する動力学モデル

A structured model introduced by considering algal mass to be composed of two components which were an intracellular phosphate and a structural substance, was proposed for algal phosphate uptake and growth dynamics. Further, the kinetics for phosphate uptake and growth of Microcystis aeruginosa were investigated at steady state or transient state, using continuous and batch culture experiments.Continuous culture experiments indicated that specific growth rate, μ was expressed as a hyperbolic function of intracellular phosphorus content, fP. While, specific rate of phosphate uptake, σ was inversely as fP. The fP values ranged from a maximum of about 5.0% to a minimum of about 0.15% phosphate per cell dry weight.At balanced growth, σ was related to μ and fP in the form of σ=fP·μ which was derived from the model presented here. So, parabolic relationship was found between σ and μ, because fP increased with increasing μ.The kinetic equation of transient phosphate uptake was given by dfp/dt=σ-μ·fP. This kinetic model was able to simulate overplus phenomena that when M. aeruginosa grown in a phosphate deficient continuous culture was suddenly brought into contact with a phosphate rich medium, phosphate was accumulated into the cell above the intracellular content required to sustain maximum growth rate.

“Unattached” Fraction of Short-lived Rn Decay Products in Indoor and Outdoor Environments

The unattached fraction fp of potential alpha energy of short-lived Rn decay products was measured under realistic, natural conditions in different dwellings and in the open atmosphere by a single-screen technique. An improved data evaluation method was developed where the measured activities of 218Po (RaA) and 214Pb (RaB) were corrected by the screen-attached activities of 214Bi (214Po) [RaC (RaC')]. This method is based on the experimental observation that the 214Bi (214Po) unattached activities are negligible under realistic living conditions and that the size distributions of the aerosol-attached activities of all short-lived Rn daughters are identical. In closed rooms without additional aerosol sources, a mean unattached fraction fp of the potential alpha energy of 0.096 was obtained at a mean aerosol particle concentration of 6100 cm-3 and at a mean equilibrium factor F of 0.30. This mean fp value is about three times higher than the value used in the literature for the radiation exposure calculation of the human public. In closed rooms with additional aerosol sources (cigarette smoke, heating systems, aerosols from a burning candle), the aerosol particle concentrations ranged up to 10(6) cm-3 and the attachment rates, X, increased up to 1000 h-1. The fp values sometimes decreased below the detection limit of 0.005, and the F values increased to as high as 0.77. In the ambient atmosphere in the vicinity of Göttingen, a mean unattached fraction fp of 0.02 and a mean aerosol particle concentration of 3.4 x 10(4) cm-3 were measured at 1 m above the ground. The mean equilibrium factor F was determined to be 0.7.

A Chlorophyll Fluorescence Screening Test to Evaluate Chilling Tolerance in Tomato

The chilling tolerance of commercial Lycopersicon esculentum cultivars (H2653, H722), Solanum lycopersicoides, an F1 hybrid of S. lycopersicoides × Sub-Arctic Maxi, and 25 BC2F2 lines of L. hirsutum × H722 (backcrossed twice to H722) was evaluated using a chlorophyll fluorescence assay. The ratio of the initial to the peak fluorescence (Fo: Fp) measured from fully expanded leaves was chosen as an indicator of plant health. Chilling induced an increase in Fo: Fp that was correlated with the sensitivity of the plant to low-temperature stress. Values of Fo: Fp remained low for cold-treated S. lycopersicoides and the F1 hybrid, which showed few symptoms of chilling-related damage, whereas the commercial cultivars, which were essentially intolerant to low temperatures, had large increases in Fo: Fp. A full range of Fo: Fp values was measured in the 25 BC2F2 lines, indicating that some chilling tolerance from the L. hirsutum parent was expressed by plants in these populations.

Possible Effect of Lactational Period on the Milk-to-Plasma Drug Concentration Ratio in Lactating Women: Results of an In Vitro Evaluation

The fat and protein composition of human milk changes dramatically in the first several weeks postpartum. In order to investigate the possible effect of this compositional change on the milk-to-plasma drug concentration ratio (M/P), the following experiment was performed. Milk samples were collected from five healthy lactating women on days 3, 5, 7, and 14 postpartum; blood samples were obtained on these days, as well as on day 1. Serum and skim milk unbound fractions (fp and fm, respectively) and the skim milk-to-whole milk drug concentration ratio (S/M) were determined in vitro in the above samples for diazepam, propranolol, and etretin, an aromatic retinoid. In addition, the composition of these milk and serum samples was also assessed. Using a previously proposed mathematical model for the distribution of drugs between milk and plasma, M/P was calculated from values for fm, fp, S/M, milk pH, and literature values for the pKa values of the compounds. The M/P was calculated for each subject on each day of sample collection. Total serum protein and alpha-1-acid glycoprotein (AAG) levels increased in the first two weeks postpartum. Mean diazepam fp values fell from 0.020 to 0.014 during this period, while propranolol fp values changed inversely with serum AAG levels. Milk whey and total proteins decreased as lactation progressed, but changes in fat levels were not statistically significant. Calculated propranolol M/P increased during the study period, predominately due to changes in milk pH and propranolol S/M.(ABSTRACT TRUNCATED AT 250 WORDS)