SEARCH · PubMed Health

Results for “Particle Size”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

PubMed2005

Relations between particle size of HDL and LDL lipoproteins and cholesterol esterification rate.

Particle size of low density (LDL) and high density (HDL) lipoproteins and cholesterol esterification rate in HDL plasma (FER(HDL)) are important independent predictors of coronary artery diseases (CAD). In this study we assessed the interrelations between these indicators and routinely examined plasma lipid parameters and plasma glucose concentrations. In 141 men, healthy volunteers, we examined plasma total cholesterol (TC), triglycerides (TG), HDL and LDL cholesterol (HDL-C, LDL-C) and HDL unesterified cholesterol (HDL-UC). Particle size distribution in HDL and LDL was assessed by gradient gel electrophoresis and FER(HDL) was estimated by radioassay. An effect of particle size and FER(HDL) on atherogenic indexes as the Log(TG/HDL-C) and TC/HDL-C was evaluated. Subjects in the study had plasma concentrations (mean +/- S.D.) of TC 5.2+/-0.9 mmol/l, HDL-C 1.2+/-0.3 mmol/l, TG 2.1+/-1.7 mmol/l, glucose 5+/-0.8 mmol/l. Relative concentration of HDL(2b) was 17.6+/-11.5 % and 14.6+/-11.8 % of HDL(3b,c). The mean diameter of LDL particles was 25.8+/-1.5 nm. The increase in FER(HDL) significantly correlated with the decrease in HDL(2b) and LDL particle size (r = -0.537 and -0.583, respectively, P<0.01) and the increase in HDL(3b,c) (0.473, P<0.01). Strong interrelations among TG and HDL-C or HDL-UC and FER(HDL) and particle size were found, but TC or LDL-C did not have such an effect. Atherogenic indexes Log(TG/HDL-C) and TC/HDL-C correlated with FER(HDL) (0.827 and 0.750, respectively, P<0.0001) and with HDL and LDL particle size.

Adult↗

PubMed2004

Influence of particle size and shape on flowability and compactibility of binary mixtures of paracetamol and microcrystalline cellulose.

The influence of the size and shape of paracetamol particles on the flow and compression behavior of blends (1:1) of microcrystalline cellulose (MCC) was investigated. The effect of paracetamol particle shape was investigated by using two differently prepared samples, micronized and novel engineered Solution Atomization and Xstallization by Sonication (SAXS) particles, which exhibited similar particle size ranges (2-6 microm). The results were compared to data obtained for an untreated paracetamol sample. The blends containing SAXS particles exhibited increased bulk and tapped density and improved flow, compared to the blend containing micronized particles. This may reflect differences in shape since the SAXS particles exhibited spherical morphology. The compressibility of the blend containing untreated paracetamol was greater than blends containing the SAXS and micronized materials, which may reflect the different drug particle sizes and shapes. However, blends containing the needle-shaped particles of pure untreated sample, exhibited poor compactibility after storage at 10% RH. It was found that increasing the moisture content in the blends by storage at 44% RH resulted in an increase in the compactibility of the samples containing untreated and SAXS paracetamol with the blends containing micronized paracetamol being relatively unaffected. In general, tablets prepared from blends containing smaller particles of paracetamol exhibited significantly greater compactibility compared to tablets prepared containing the larger particle sized untreated paracetamol. The use of small, spherical drug particles may result in improvements in the bulk density, densification and compactibility of blends of paracetamol and microcrystalline cellulose.

Acetaminophen↗

PubMed1996

In situ particle size reduction as affected by forage species and grinding mesh size.

Two ruminally cannulated heifers were used to evaluate effects of three forage species (gamagrass, orchardgrass, and red clover) ground through two mesh sizes (2 and 5 mm) in a 3 x 2 factorial arrangement on particle size reduction in situ. Residues in polyester bags incubated for 3, 6, 12, 24, 36, 48, 60, and 72 h were analyzed for mean particle size. Initially, gamagrass had a 10.2% greater (P < .05) proportion of DM as particles larger than 300 microns that did orchardgrass or red clover, whereas forages ground through a 5-mm mesh (5-mm forage) had a 7.5% greater (P < .05) proportion of DM as 300 microns or larger particles than forages ground through a 2-mm mesh (2-mm forage). Mean particle size decreased with incubation time, resulting in reductions of 44, 42, 53, and 49% of gamagrass, orchardgrass, and 2- and 5-mm forages, respectively, after 60 h. Mean particle size of red clover was reduced 67% after 36 h of incubation. Particle size reduction was initiated earlier (12 vs 36 h) and occurred at a 150% faster (P < .01) rate for red clover than for gamagrass or orchardgrass. Although there was no difference (P > .10) between grinding mesh size at the time at which particle size reduction was initiated (24 h), particle reduction occurred at a 136% faster (P < .05) rate for forages ground through a 5-mm screen than for forages ground through a 2-mm screen. A greater (P < .10) reduction (595 microns by 36 h) in mean particle size occurred in red clover than in gamagrass or orchardgrass (average 376 microns by 60 h) during ruminal incubation. In addition, 5-mm forages exhibited a greater (P < .10) reduction in mean particle size (527 microns) than did 2-mm forages (372 microns) after 60 h of incubation. Substantial particle size reduction occurred in situ due to microbial digestion. The faster particle size reduction found in red clover may contribute to the greater observed intake for legumes.

Animal Feed↗

PubMed2005

Particle size analysis of some water/oil/water multiple emulsions.

Particle size analysis gives useful information about the structure and stability of multiple emulsions, which are important characteristics of these systems. It also enables the observation of the growth process of particles dispersed in multiple emulsions, accordingly, the evolution of their dimension in time. The size of multiple particles in the seven water/oil/water (W/O/W) emulsions was determined by measuring the particles size observed during the microscopic examination. In order to describe the distribution of the size of multiple particles, the value of two parameters that define the particle size was calculated: the arithmetical mean diameter and the median diameter. The results of the particle size analysis in the seven multiple emulsions W/O/W studied are presented as histograms of the distribution density immediately, 1 and 3 months after the preparation of each emulsion, as well as by establishing the mean and the median diameter of particles. The comparative study of the distribution histograms and of the mean and median diameters of W/O/W multiple particles indicates that the prepared emulsions are fine and very fine dispersions, stable, and presenting a growth of the abovementioned diameters during the study.

Emulsions↗

PubMed2001

Oral 17beta-estradiol and medroxyprogesterone acetate therapy in postmenopausal women increases HDL particle size.

Menopause is accompanied by changes in lipoprotein particles that include an increase in density of low density lipoproteins (LDL) and high density lipoproteins (HDL) particles. The effect of 3 months of oral hormone replacement therapy (HRT) on lipoprotein particle size in postmenopausal women who were randomized to (1) estrogen replacement therapy (ERT) alone (either 17beta-estradiol (1 mg) or conjugated equine estrogens (CEE) (0.625 mg); (2) combination therapy (17beta-estradiol plus medroxyprogesterone acetate (MPA) or CEE plus MPA); and (3) placebo were examined. Lipoprotein subclass concentrations and particle size were quantified by nuclear magnetic resonance spectroscopy (NMR). Combination HRT resulted in significant (P=0.002) increases in HDL particle size as compared with those on placebo formulations or ERT alone. Women assigned to combined HRT had lower concentrations of smaller HDL particles after 3 months (P=0.005) and higher concentrations of larger HDL particles (P=0.02), whereas women assigned to ERT or placebo experienced non-significant changes. In summary, combined HRT increases HDL particle size by altering concentrations of the smallest and largest HDL subspecies.

Administration, Oral↗

PubMed2006

Study of particle size effects on an optical fiber sensor response examined with Monte Carlo simulation.

Optical fiber sensors based on the total light transmittance are widely used to measure the volume fraction of particles in suspensions. However, the sensor response depends not only on the volume fraction but also on the particle size. The particle size effect is studied for a sensor configuration consisting of two linear arrays of fibers on each of two blocks: the emitting and receiving blocks. These two linear arrays are arranged with three adjacent fibers (one fiber on the first array, two fibers on the second array) forming a perfect triangle. The almost superimposition of the calculated sensor response versus the extinction factor for different particle sizes allows for the application of single- curve models. Two single-curve models that describe the sensor response for all particle sizes ranging from 36 to 200 microm are proposed. The models are validated by Monte Carlo simulation for different particle sizes and are valid within a detectable volume fraction. The single-curve models proposed provide an easier approach to creating a database for sensor calibration for suspended sediment concentration measurements.

Journal Article↗

PubMed2005

Simulation of the evolution of particle size distributions in a vehicle exhaust plume with unconfined dilution by ambient air.

Over the past several years, numerous studies have linked ambient concentrations of particulate matter (PM) to adverse health effects, and more recent studies have identified PM size and surface area as important factors in determining the health effects of PM. This study contributes to a better understanding of the evolution of particle size distributions in exhaust plumes with unconfined dilution by ambient air. It combines computational fluid dynamics (CFD) with an aerosol dynamics model to examine the effects of different streamlines in an exhaust plume, ambient particle size distributions, and vehicle and wind speed on the particle size distribution in an exhaust plume. CFD was used to calculate the flow field and gas mixing for unconfined dilution of a vehicle exhaust plume, and the calculated dilution ratios were then used as input to the aerosol dynamics simulation. The results of the study show that vehicle speed affected the particle size distribution of an exhaust plume because increasing vehicle speed caused more rapid dilution and inhibited coagulation. Ambient particle size distributions had an effect on the smaller sized particles (approximately 10 nm range under some conditions) and larger sized particles (>2 microm) of the particle size distribution. The ambient air particle size distribution affects the larger sizes of the exhaust plume because vehicle exhaust typically contains few particles larger than 2 microm. Finally, the location of a streamline in the exhaust plume had little effect on the particle size distribution; the particle size distribution along any streamline at a distance x differed by less than 5% from the particle size distributions along any other streamline at distance x.

Air Pollutants↗

PubMed1990

Particle size reduction during initial mastication of forages by dairy cattle.

Four experiments were conducted with dairy cattle to determine the effects of initial feed particle size and moisture content on particle size of ingested masticates. Three mature Holstein cows were used in either latin square or Youden square designs. Samples of masticated and ingested boli were collected at the cardiac opening through a ruminal fistula between 0 and 5, 5 and 10 and 10 and 15 min after meal initiation. In Exp. 1, masticate log mean particle sizes (LMPS) (ln microns, log normal distribution) were 3.50, 3.53 and 3.50 for corn silage, fine-chopped alfalfa haylage and coarse-chopped alfalfa haylage, respectively. In Exp. 2, boli LMPS for ground, chopped and long alfalfa hay were 3.11, 3.76 and 4.09, respectively. Boli LMPS in Exp. 3 for ground, chopped and long timothy hay were 2.93, 3.12 and 3.03, respectively. Exp. 4 compared the effect of addition of water to produce 30%, 47%, 64% and 82% DM in chopped alfalfa hay. Boli LMPS were 3.66, 3.56, 3.64 and 3.68 for the respective alfalfa hay DM contents. Feed LMPS was not reduced during mastication in Exp. 4, nor were there differences in LMPS due to time after feeding. Boli LMPS was affected by feed particle size of alfalfa hay, but there was no effect of feed particle size on masticate particle size in timothy hay. The magnitude of particle size reduction during mastication appears to be dependent on forage type and is not dependent totally on initial feed particle size and DM content of forages.

Animal Feed↗

PubMedDate not supplied

Particle size reduction of emulsions by formulation design-II: effect of oil and surfactant concentration.

The objective of this study was to investigate the effect of the concentration of surfactant and oil on particle size reduction and stability of oil-in-water emulsion formulations containing polyhydroxy alcohols. Emulsions were prepared using an emulsifier system consisting of Tween 80 and Span 80 with 5%, 10%, 15% and 20% soybean oil and containing 50% w/w of either propylene glycol (PG) or glycerol (GLY) in the external phase. At each oil concentration, four emulsions were formulated with increasing surfactant concentration to provide emulsions with surfactant to oil (S/O) ratios of 0.1, 0.2, 0.3 and 0.4. Three parameters were evaluated, particle size reduction, particle size stability upon dilution, and viscosity. It was found that increase in S/O ratio resulted in substantial decrease in particle size in all cases. But there was a difference in the particle size reduction pattern between PG and GLY. Increase in oil concentration at the same S/O ratio caused particle size reduction for emulsions with PG but not for emulsions with GLY. The reduction in particle size was also greater for emulsions containing PG. Further, particle size of emulsions containing PG was found to be stable over 24 hours after dilution. However, a slight increase in particle size was observed in emulsions containing GLY. It was also found that the viscosity of emulsions increased with an increase S/O ratio as well as the concentration of the oil.

Drug Compounding↗

PubMed1998

Moisture content and particle size of dehydrated egg yolk affect lipid and cholesterol extraction using supercritical carbon dioxide.

Egg yolk was spray-dried under conditions to produce a small particle size powder and a large particle size powder. Particle size was determined using a Nikon Optiophot microscope. Spray-dried egg yolk was also adjusted to various moisture levels as follows: control (2 to 4% moisture), 7% moisture, and 12% moisture. Supercritical carbon dioxide extraction (SCE) of each of these moisture treatments at 45 C/306 atm using 30 g CO2/g of sample was completed. For the particle size study, 45 g CO2/g of sample at 45 C/306 atm was utilized. Particle size exhibited a significant effect on cholesterol and lipids extracted using SCE. As moisture content of dried egg yolk increased to 7%, there was a significant increase in lipids extracted using supercritical carbon dioxide. Moisture content had no significant effect on cholesterol extraction. After extracting SCE higher moisture spray-dried egg yolk, sponge cake volume was significantly reduced compared to that of the control. The reduced sponge cake volume may be due to protein denaturation.

Animals↗

PubMed1990

Particle size and content uniformity.

The requirements of the USP Content Uniformity test are translated into physical and mathematical parameters. Assuming spherical particle sizes with a log normal distribution, the mean particle size and particle size distribution required to insure a high probability of passing the content uniformity test are calculated. On the basis of these calculations it is shown that satisfactory tablets of low doses cannot be manufactured from a drug that does not meet certain particle size distribution specifications. It is recommended that particle size specifications for low dose drugs include a requirement for a limit to size distribution.

Particle Size↗

PubMed2000

Strategies for maintaining the particle size of peptide DNA condensates following freeze-drying.

The particle size of peptide DNA condensates were studied after freeze-drying and rehydration as a function of sugar excipient, concentration, pH, DNA concentration, and peptide condensing agent. In the absence of an excipient, freeze-dried 50 microg/ml AlkCWK(18) (iodoacetic acid alkylated Cys-Typ-Lys(18)) DNA condensates formed large fibrous flocculates on rehydration. Of the sugars tested as lyoprotectants, sucrose proved most effective at preserving particle size during rehydration. The addition of 5 wt/vol% sucrose preserved a mean particle diameter of less than 50 nm during rehydration of AlkCWK(18) DNA condensates prepared at DNA concentrations up to 200 microg/ml; however, higher DNA concentrations led to the formation of insoluble fibrous flocculates. Substitution of polyethylene glycol (PEG)-CWK(18) as a DNA condensing peptide eliminated the need for sucrose, resulting in peptide DNA condensates that retained particle size when rehydrated in water or normal saline at concentrations up to 5 mg/ml. The results suggest that sucrose functions primarily as a bulking agent during freeze-drying that only preserves the particle size of AlkCWK(18) DNA condensates up to a maximum concentration of 200 microg/ml. Alternatively, the steric layer created on the surface of PEG-CWK(18) DNA condensates provides far more efficient lyoprotection, preserving their particle size at a concentration of 5 mg/ml without a bulking agent.

DNA↗

PubMed2005

Pleiotropic genetic effects contribute to the correlation between HDL cholesterol, triglycerides, and LDL particle size in hypertensive sibships.

OBJECTIVE: Abnormalities of HDL cholesterol (HDL-C), triglycerides, and LDL particle size are present in familial dyslipidemic hypertension. We investigated heritability of these three lipid traits and the extent to which shared effects of genes (pleiotropy) contribute to the additive genetic variation in each trait in hypertensive sibships. METHODS: Subjects included 788 individuals (60% women) ascertained through sibships with >/=2 members diagnosed with hypertension before age 60 years. The LDL particle size was measured by polyacrylamide gel electrophoresis. Triglycerides were log transformed to reduce skewness, and age- and sex-adjusted lipid traits were used in the analyses. Heritability and pairwise genetic correlations were computed using a variance components approach. The genetic correlation between a pair of traits was squared to yield genetic covariance, a measure of pleiotropic effects of genes influencing both traits concomitantly. RESULTS: Heritability estimates indicated significant genetic effects on HDL-C (0.58), log triglycerides (0.47), and LDL particle size (0.71). Genetic correlation was strongest between HDL-C and log triglycerides (-0.642), followed by log triglycerides and LDL particle size (-0.493), and HDL-C and LDL particle size (0.334). HDL-C and log triglycerides showed the strongest genetic covariance (41%), followed by LDL particle size and log triglycerides (24%), and HDL-C and LDL particle size (11%). CONCLUSIONS: Multivariate quantitative genetic analyses in hypertensive sibships reveal that pleiotropy contributes to the additive genetic variation in HDL-C, triglycerides, and LDL particle size. These findings provide the rationale for multivariate linkage analyses to identify novel genetic loci with pleiotropic effects on the traits.

Aged↗

PubMed1981

Effect of calcium carbonate particle size on the available phosphorus requirement of broiler chicks.

Sixteen hundred broiler strain cockerels housed in battery brooders 1 to 21 days of age were used to determine the effect of feeding different commercially available particle-sized calcium carbonate (CaCO3) on the phosphorus requirement. Five replicates of 8 chicks each were fed corn-soy type diets consisting of either 12 to 20, 20 to 60, or 100 to 200 (passed-retained basis) United States Bureau of Standards (USBS) sieve-sized CaCO3. Each particle-sized CaCO3 was fed in diets containing either .20 to .30% (Experiment 2), or .20 to .45% (Experiment 3) available phosphorus (AP) with .05% increments. Supplementary phosphorus was added as sodium phosphate monobasic. Tibia ash and body weight were greater when the USBS 20 to 60 particle-sized CaCO3 was fed then when either the USBS 12 to 20 or 100 to 200 particle-sized CaCO3 was fed. 90% dietary calcium was fed to broiler chicks, the phosphorus requirement was either .35% AP with the USBS 20 to 60 particle-sized CaCO3 or at least .45% AP with either the USBS 12 to 20 or 100 to 200 particle-sized CaCO3. Blood alkaline phosphatase, which indicates bone calcification, was inversely correlated (r = -.65) with bone ash. Blood calcium and blood phosphorus increased, and blood alkaline phosphatase decreased with increasing dietary phosphorus. These data show that the 21-day-old broiler chick's available phosphorus requirement is less in corn-soybean meal diets containing a USBS 20 to 60 particle-sized CaCO3 than in diets containing either the USBS 12 to 20 or 100 to 200 particle-sized CaCO3.

Animals↗

PubMed2006

Identification of physical-chemical variables affecting particle size following precipitation using a supercritical fluid.

The physical-chemical processing variables affecting particle size following precipitation using the supercritical antisolvent (SAS) method were investigated by varying both the composition of the feed solvent and the structure of the solute, using a series of steroids. The key factor influencing particle size in these studies appears to be the solubility of the drug in the organic solvent/supercritical fluid mixture, where relatively high solubility causes a lower degree of supersaturation in the precipitation vessel, resulting in a relatively large particle size. Higher operating pressures result in larger particle sizes, probably through the effect of pressure on solubility. Physical properties of the carrier solvent, such as vapor pressure and dielectric constant, were not effective predictors of relative particle size of the precipitated powder, nor was solubility of the model drug in the carrier solvent. In limited studies of the physical state of the precipitated solid, higher apparent crystallinity was observed for powders with larger particle size. A precipitate of a different crystal form was observed when starting with hydrocortisone hemisuccinate monohydrate and may represent the loss of water of hydration. An amorphous solid was precipitated when starting with yttrium acetate dihydrate. Broad guidelines for effective particle size reduction using this technique are presented.

Chemical Phenomena↗

PubMed2003

Droplet and particle size relationship and shell thickness of inhalable lactose particles during spray drying.

To find means of controlling the size and density of particles intended for inhalation the relationship between droplet and particle size during spray drying was investigated. Lactose solutions were atomized with a two-fluid nozzle and dried in a laboratory spray drier. The effects of nozzle orifice diameter, atomization airflow and feed concentration on droplet and particle size were examined. Mass median diameter of both droplets and particles were analyzed with laser diffraction. In addition, scanning electron microscopy and transmission electron microscopy were used for studies of particle shape and morphology. It was demonstrated that nozzle orifice diameter and airflow, but not feed concentration controlled the droplet size during atomization. Increasing droplet size increased particle size but the effect was also influenced by feed concentration. Particles from solutions of a low concentration (1% w/w) were smaller than those from higher concentrations (5-20% w/w). This may be partly explained by lower yields at higher feed concentrations, but may also be related to differences in drying rate. Spray-dried lactose solutions formed hollow particles, and it was suggested that the shell thickness of the particles increased with increasing feed concentration.

Administration, Inhalation↗

PubMed2000

Protein spray-freeze drying. Effect of atomization conditions on particle size and stability.

PURPOSE: To investigate the effect of atomization conditions on particle size and stability of spray-freeze dried protein. METHODS: Atomization variables were explored for excipient-free (no zinc added) and zinc-complexed bovine serum albumin (BSA). Particle size was measured by laser diffraction light scattering following sonication in organic solvent containing poly(lactide-co-glycolide) (PLG). Powder surface area was determined from the N2 vapor sorption isotherm. Size-exclusion chromatography (SEC) was used to assess decrease in percent protein monomer. Fourier-transform infrared (FTIR) spectroscopy was employed to estimate protein secondary structure. PLG microspheres were made using a non-aqueous, cryogenic process and release of spray-freeze dried BSA was assessed in vitro. RESULTS: The most significant atomization parameter affecting particle size was the mass flow ratio (mass of atomization N2 relative to that for liquid feed). Particle size was inversely related to specific surface area and the amount of protein aggregates formed. Zinc-complexation reduced the specific surface area and stabilized the protein against aggregation. FTIR data indicated perturbations in secondary structure upon spray-freeze drying for both excipient-free and zinc-complexed protein. CONCLUSIONS: Upon sonication, spray-freeze dried protein powders exhibited friability, or susceptibility towards disintegration. For excipient-free protein, conditions where the mass flow ratio was > -0.3 yielded sub-micron powders with relatively large specific surface areas. Reduced particle size was also linked to a decrease in the percentage of protein monomer upon drying. This effect was ameliorated by zinc-complexation, via a mechanism involving reduction in specific surface area of the powder rather than stabilization of secondary structure. Reduction of protein particle size was beneficial in reducing the initial release (burst) of the protein encapsulated in PLG microspheres.

Biocompatible Materials↗

PubMed2003

The effect of corn silage particle size on eating behavior, chewing activities, and rumen fermentation in lactating dairy cows.

The objective of this experiment was to evaluate effects of reducing corn silage particle size on eating behavior, chewing activity, and rumen fermentation in lactating dairy cows. Four cannulated, multiparous cows averaging 110 +/- 4 d in milk and weighing 675 +/- 70 kg were randomly assigned to a 4 x 4 Latin square. During each of four 14-d periods, animals were offered one of four diets that were chemically similar but varied in corn silage particle size: short (SH), mostly short (MSH), mostly long (MLG), and long (LG), with a geometric mean particle length of 7.4, 7.8, 8.3, and 8.8 mm, respectively. Reducing particle size increased dry matter intake (DMI) linearly (28.0, 26.8, 26.8, and 25.7 kg/d for SH, MSH, MLG, and LG respectively). At 8, 16, and 24 h postfeeding, the neutral detergent fiber (NDF) concentration of feed remaining in the bunk decreased linearly with reduced particle size. Time spent eating or ruminating was not different across treatments; however, total chewing activity (TC; sum of time spent eating and ruminating) exhibited a quadratic response with highest chewing activities observed for diets with shortest and longest particle size. Eating or ruminating time per kilogram of DMI was not affected by corn silage particle size, but TC per kilogram of DMI decreased linearly with decreasing particle size. In comparison, when expressed as minutes per unit of NDF intake (NDFI), ruminating, and TC were linearly reduced as particle size decreased. Rumen pH was not affected by corn silage particle size even though total concentration of volatile fatty acids increased linearly from 89.1 mM/L to 93.6 mM/L as diet particle size decreased. A quadratic effect was observed in molar proportion of acetate and propionate with the highest concentration observed in animals consuming diets of intermediate particle size. Results of this experiment suggest that reducing corn silage particle size may increase DMI, positively affect rumen fermentation, and reduce sorting behavior. Because both chewing activity and sorting tendencies increased when proportion of TMR particles > 19.0 mm increased, results suggest that particle size measurement as estimated by the PSPS is useful in understanding some factors that affect feeding behavior.

Ammonia↗