scholarly journals Biases Associated with Four Stream Substrate Samplers

1991 ◽  
Vol 48 (10) ◽  
pp. 1882-1886 ◽  
Author(s):  
Michael K. Young ◽  
Wayne A. Hubert ◽  
Thomas A. Wesche
Keyword(s):  
Particle Size ◽  
Geometric Mean ◽  
The Other ◽  
Substrate Composition ◽  
Mean Particle Size ◽  
Core Samples ◽  
Freeze Core ◽  
Single Probe ◽  
Core Sampler ◽  
Stream Substrate

We compared samples collected from 10 substrates of various compositions with a single-probe freeze-core sampler, a triple-probe freeze-core sampler, a McNeil sampler, and a shovel. The accuracy with which these devices sampled particles larger than 50 mm in diameter varied; they were oversampled by the freeze-core devices, sampled in proportion to their availability by a shovel, and sampled inconsistently by the McNeil sampler. The geometric mean particle size and variance of single-probe freeze-core samples consistently exceeded those of samples collected with the other devices. Most sample means also exceeded the test substrate means. By excluding the proportions of particles larger than 50 mm in diameter in our analyses, we found that proportions of several particles sizes in samples collected by different methods differed significantly from the actual proportions in test substrates. There were few differences between the single- and triple-probe freeze-core samples or between McNeil and shovel samples. All four samplers were biased, but the McNeil sampler most frequently produced samples that approximated the true substrate composition.

Cytoplasmic glycogen inclusions in cells of anaerobic gram-negative rumen bacteria

1973 ◽  
Vol 19 (12) ◽  
pp. 1501-1506 ◽  
Author(s):  
K.-J. Cheng ◽  
R. Hironaka ◽  
D. W. A. Roberts ◽  
J. W. Costerton
Keyword(s):  
Particle Size ◽  
Energy Content ◽  
Rumen Fluid ◽  
Geometric Mean ◽  
Enteric Bacteria ◽  
High Energy ◽  
Rumen Bacterium ◽  
Rumen Bacteria ◽  
Absorption Bands ◽  
Mean Particle Size

Megasphaera elsdenii, an anaerobic rumen bacterium, produced intracellular polysaccharide granules varying in size from 0.05 to 0.15 μm during growth in batch culture. This polysaccharide material was purified and was found to contain D-glucose as the only reducing sugar. The polyglucose polymer was highly opalescent in aqueous solution and formed a strong reddish-brown iodine complex with a maximum absorbance at 493 nm. Its infrared spectrum had characteristic absorption bands at 8.70, 9.25, and 9.75 μm and was identical with that of the glycogen of enteric bacteria and beef liver. When these polysaccharide granules were observed with an electron microscope, they resembled the glycogen granules produced by Arthrobacter globiformis and Escherichia coli. These properties indicate that the polysaccharide was a type of glycogen. The yield of crude glycogen was 16.82% of the dry weight of late log-phase cells (14-h).The lysis of cells of M. elsdenii and other rumen bacteria that store polysaccharide granules inside the cells, in the rumen of cows fed a feed of fine-particle size (344 μm, geometric mean particle size) and high-energy content, may contribute to the high-carbohydrate level and high viscosity of the cell-free rumen fluid of these cows. Cows fed a coarse feed (519 μm, geometric mean particle size) of the same composition have rumens that contain few bacteria with polysaccharide granules. The cell-free rumen fluid of these cows has low viscosity and low-carbohydrate content.

INFLUENCE OF FEED PARTICLE SIZE ONpH, CARBOHYDRATE CONTENT, AND VISCOSITY OF RUMEN FLUID

1973 ◽  
Vol 53 (3) ◽  
pp. 417-422 ◽  
Author(s):  
K.-J. CHENG ◽  
R. HIRONAKA
Keyword(s):  
Particle Size ◽  
Fine Particle ◽  
Rumen Fluid ◽  
Geometric Mean ◽  
Coarse Particle ◽  
Soluble Carbohydrate ◽  
Mean Particle Size ◽  
Fine Particle Size ◽  
Fluid Properties ◽  
Carbohydrate Levels

Four fistulated cows were used to compare the rumen fluid properties produced from feeding all-concentrate feeds of fine (344 μ), or coarse (519 μ) geometric mean particle size, or alfalfa hay. A severe frothy condition developed in the rumens of cows fed the fine particle size feed but not in the rumens of cows fed the coarse or hay diets. The average viscosity of rumen fluid from cows fed hay was 7.4 centipoises (cP), about 14.7 cP when fed the coarse feed, and about 30.7 cP when fed the fine feed. After the cows became accustomed to their feed, rumen fluid pH declined from 6.5 to 5.6 when fed the fine particle feed and from 6.9 to 6.0 when fed the coarse. The rumen fluid from the cows fed the fine feed exhibited two viscosity maxima, between pH 5.5 and 5.8, and between pH 7.5 and 8.5, whereas the viscosity of the rumen fluid from the cows fed the coarse feed was not influenced by pH. Soluble carbohydrate levels were 650 μg/ml in the rumen fluid of cows fed the coarse-particle diet and over 1,000 μg/ml in that from cows fed the fine-particle feed. Cows fed hay had less than 300 μg/ml of soluble carbohydrate in the rumen fluid.

1445 Commercial ground corn surface area is better related to rumen disappearance than geometric mean particle size

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 701-701
Author(s):  
J. P. Goeser ◽  
B. Beck ◽  
T. Koehler ◽  
D. Tanata ◽  
E. Reid ◽  
...  
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Geometric Mean ◽  
Mean Particle Size ◽  
Ground Corn

Defect Behaviour in Yttria-Stabilised Zirconia Nanomaterials Studied by Positron Annihilation Techniques

2012 ◽  
Vol 331 ◽  
pp. 181-199 ◽  
Author(s):  
Ivan Procházka ◽  
Jakub Čížek ◽  
Oksana Melikhova ◽  
Jan Kuriplach ◽  
Wolfgang Anwand ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Boundaries ◽  
Positron Annihilation ◽  
Intensity Ratio ◽  
Positron Annihilation Spectroscopy ◽  
The Other ◽  
Mean Particle Size ◽  
Other Hand ◽  
The Mean ◽  
Strong Segregation

Recent experimental and theoretical investigations on a variety of yttria-stabilised zirconia (YSZ) nanomaterials are reviewed. The investigations were conducted within the frame of a collaboration of three institutions: (i) Charles University in Prague, (ii) Helmholtz Centre Dresden-Rossendorf and (iii) Donetsk Institute for Physics and Engineering of the NAS of Ukraine, Materials studied involved pressure-compacted nanopowders of binary and ternary (with Cr2O3 additive) YSZ and YSZ ceramics obtained by sintering the nanopowders. The nanopowders were prepared by the co-precipitation technique. Positron annihilation spectroscopy including the conventional positron lifetime (LT) and coincidence Doppler broadening (CDB) techniques was employed as the main experimental tool. Slow positron implantation spectroscopy (SPIS) was used in investigation of commercial YSZ single crystals for reference purposes. Extended state-of-art theoretical ab-initio calculations of positron response in the ZrO2 lattice were carried out for various vacancy-like defect configurations. It was suggested by these calculations that none of the oxygen-vacancy related defects are capable to trap positrons. On the other hand, zirconium vacancy was demonstrated by the calculations to be a deep positron trap, even in the case that a hydrogen atom is attached to the vacancy. The measured positron LT data clearly indicated that positrons annihilate in nanopowders predominantly from trapped states at defects of two kinds: (a) the vacancy-like misfit defects concentrated in layers along the grain boundaries and characterised with lifetimes of 0.180 ns, and (b) the larger defects of open volume comparable to clusters of a few vacancies which are situated at intersections of three (or more) grain boundaries (characteristic lifetimes of 0.380 ns). The intensity ratio of LT components corresponding to these two kinds of defects was found to be correlated with the mean particle size. This correlation reconfirms the above interpretation of LT components and, moreover, the measured ratios could be used to estimate changes of the mean particle size with chromia content or sintering temperature. It was shown in this way that chromia addition to the YSZ nanopowder leads to a smaller particle size compared to the binary YSZ. Similarly, grain growth during sintering could be monitored via this intensity ratio. A portion of 10 % of positrons was found to form positronium (Ps) in compacted binary YSZ nanopowders. The observed ortho-Ps lifetimes correspond to Ps pick-off annihilation in cavities of 3 nm size which may be expected to occur between the primary nanoparticles. On the other hand, an addition of chromia at a concentration as low as 0.3 mol.% appeared to be sufficient to suppress Ps formation below the detection limit. Similarly, Ps formation could not be detected in binary YSZ sintered for 1 hour at a temperature of 1000 °C or higher. The former effect indicates an enhanced concentration of Cr cations at the particle surfaces, while the latter one appears to be due to a decrease of cavity concentration induced by sintering. The measured CDB data supported the idea that vacancy-like trapping centres are similar to zirconium vacancies and gave further evidence of a strong segregation of Cr segregation at particle interfaces. SPIS was further involved in a trial experiment on binary YSZ nanopowders and sintered ceramics. This experiment clearly demonstrated that SPIS may reveal valuable information about changes of depth profiles of microstructure during sintering, e.g. a sintering induced diffusion of defects from sample interior to its surface.

scholarly journals ECOLOGIA TROFICA DE Mugil curema, M. incilis y M. liza (PISCES: MUGILIDAE) EN LA CIENAGA GRANDE DE SANTA MARTA, CARIBE COLOMBIANO. I. ANALISIS CUALITATIVO Y CUANTITATIVO

2016 ◽  
Vol 18 ◽  
Author(s):  
David Osorio Dualiby
Keyword(s):  
Particle Size ◽  
Comparative Study ◽  
Stomach Contents ◽  
Vegetarian Diet ◽  
The Other ◽  
Qualitative And Quantitative ◽  
Mean Particle Size ◽  
Low Salinity ◽  
Balanced Diet ◽  
Selective Character

A comparative study has been carried out considering qualitative and quantitative aspects of the stomach contents ofMugil curema, M. inci/is and M. liza in the Ciénaga Grande de Santa Marta. The percentages of meiobenthic invertebrates in the stomach contents of M. inci/is and M. liza was high in the low salinity period, and decreased with the increase in salinity, when M. curema appeared in the Ciénaga. This species has basically vegetarian diet, eating mainly benthic diatoms; M. liza showed a detritic diet though markedly influenced by accompaning bottom meiofauna and M. incilis the most balanced diet compared to that of the other spe- * cies. Mean particle size found in theÿtomach contents were 163 nm in M. curema, 229 nm in M. incilis and 401xnm in M. liza, thus confirming a selective character in its ingestion.

scholarly journals Watermelon (Citrullus Vulgaris): An Innovative Plant that accelerates the Healing of Pulpal Wound

2016 ◽  
Vol 7 (3) ◽  
pp. 155-161
Author(s):  
Harry Agusnar ◽  
D Dennis
Keyword(s):  
Tissue Engineering ◽  
Particle Size ◽  
Wound Healing ◽  
Therapeutic Effect ◽  
Tissue Repair ◽  
The Other ◽  
Steroid Alkaloid ◽  
Citrullus Vulgaris ◽  
Mean Particle Size ◽  
The Mean

ABSTRACT Introduction Pulpal wounds are the result of injuries like iatrogenic procedures or traumatic to the pulp of teeth that disrupt the pulp. Healing of a wound is a complex and protected process of tissue repair and remodeling in response to injury. In tooth with pulpal exposure, the healing is to reconstitute the lost continuum at the pulp—dentin border in order to effectively restore the lost dentin structure. Materials and methods This study was conducted to investigate the phytoconstituents derived from watermelon (Citrullus vulgaris) and to analyze the particle size of watermelon frost. Results Watermelon, the same as the other plants, contained triterpenoid/steroid, alkaloid, flavonoid, glikosida, and saponin, while the mean particle size is 12.34 ìm. It is seen that watermelon has the ability to promote wound healing as a result of injury. Conclusion Watermelon can be developed as a plant that has a therapeutic effect for tissue engineering in dentistry, especially in the field of conservation of teeth to maintain the health of dentin—pulp complex. How to cite this article Abidin T, Agusnar H, Dennis D. Watermelon (Citrullus Vulgaris): An Innovative Plant that accelerates the Healing of Pulpal Wound. World J Dent 2016;7(3):155-161

SINTESIS DAN KARAKTERISASI NANOPARTIKEL KITOSAN – EKSTRAK KULIT BUAH MANGGIS (Garcinia Mangostana)

2013 ◽  
Vol 14 (3) ◽  
Author(s):  
Eriawan Rismana ◽  
Susi Kusumaningrum ◽  
Olivia Bunga P ◽  
Idah Rosidah ◽  
Marhamah Marhamah
Keyword(s):  
Particle Size ◽  
Sodium Tripolyphosphate ◽  
Chitosan Solution ◽  
The Other ◽  
Ionic Gelation ◽  
Garcinia Mangostana ◽  
Particle Size Analyzer ◽  
Cadmium Lead ◽  
Solvent Residue ◽  
Mold And Yeast

The chitosan – Garcinia Mangostana extract nanoparticles has been prepared by ionic gelation reaction by mixture 0.2 % chitosan solution in acetic acid with Garcinia Mangostana extract and it’s continued by reaction process with 0.1 % sodium tripolyphosphate. The particle size of material was determined by Particle Size Analyzer (PSA) that it showed in the range of 200 – 500 nm. The color, pH, water, α- mangostin, mercury, arsenic, cadmium, lead, totally microbe aerobic, totally mold and yeast, and solvent residue contents of nanoparticles were also examined by many methods that these resulted are yellow, 4.50 – 5.50, 89 – 90 %, 1.05 %, < 0.005 ppm, < 0.01 ppm, < 0.01 ppm, < 0.05 ppm, < 10 CFU/g, < 10 CFU/g and not detected, respectively. The other characterization was also observed that it’sincluded stability andTLC chromatogram. A mixture of nanoparticles with cosmetics bases was showed that it’s increased stability, homogeneity and easy to formed.

Application of Plakett-Burman Screening Design in Optimization of Process Parameters for Formulation of Canaglifozin Nanosuspension

2020 ◽  
Vol 13 (6) ◽  
pp. 5208-5216
Author(s):  
Nisha Patel ◽  
Hitesh A Patel
Keyword(s):  
Particle Size ◽  
Particle Diameter ◽  
Spherical Shape ◽  
Water Soluble ◽  
Pareto Chart ◽  
Independent Variables ◽  
Mean Particle Size ◽  
Screening Design ◽  
Stirring Time ◽  
Response Variables

In this study, we sought to improve the dissolution characteristics of a poorly water-soluble BCS class IV drug canaglifozin, by preparing nanosuspension using media milling method. A Plackett–Burman screening design was employed to screen the significant formulation and process variables. A total of 12 experiment were generated by design expert trial version 12 for screening 5 independent variables namely the amount of stabilizer in mg (X1), stirring time in hr (X2), amt of Zirconium oxide beads in gm (X3), amount of drug in mg (X4) and stirring speed in rpm (X5) while mean particle size in nm (Y1) and drug release in 10 min. were selected as the response variables. All the regression models yielded a good fit with high determination coefficient and F value. The Pareto chart depicted that all the independent variables except the amount of canaglifozin had a significant effect (p<0.001) on the response variables. The mathematical model for mean particle size generated from the regression analysis was given by mean particle size = +636.48889 -1.28267 amt of stabilizer(X1) -4.20417 stirring time (X2) -7.58333 amt of ZrO2 beads(X3) -0.105556 amt of drug(X4) -0.245167 stirring speed(X5) (R2=0.9484, F ratio=22.07, p<0.001). Prepared canaglifozin nanosuspension exemplified a significant improvement (p<0.05) in the release as compared to pure canaglifozin and marketed tablet with the optimum formulation releasing almost 80% drug within first 10min. Optimized nanosuspension showed spherical shape with surface oriented stabilizer molecules and a mean particle diameter of 120.5 nm. There was no change in crystalline nature after formulation and it was found to be chemically stable with high drug content.

Assessment of the exposure of swimmers to microbiological contaminants in fresh waters

1997 ◽  
Vol 35 (11-12) ◽  
pp. 157-163 ◽  
Author(s):  
G. J. Medema ◽  
I. A. van Asperen ◽  
A. H. Havelaar
Keyword(s):  
Geometric Mean ◽  
Microbiological Quality ◽  
The Other ◽  
Pollution Level ◽  
Intestinal Infection ◽  
E Coli ◽  
Faecal Pollution ◽  
Run Off ◽  
Thermotolerant Coliforms ◽  
Mean Concentration

As part of a prospective cohort study among triathletes to determine a relationship between the microbiological quality of fresh bathing water and the risk of acquiring an intestinal infection, the exposure of the triathletes to microbiological contaminants was assessed. Waters were collected at seven triathlons (swimming course 1–1.5km) held in the summer of 1993 and 1994 to have a range of water qualities. All were influenced by sewage effluents, most also by agricultural run-off. Samples were collected several weeks before the event to establish a sampling programme (1993) and during the actual exposure of the triathletes (1993 and 1994) and examined for thermotolerant coliforms alone (samples preceding the event) and for E. coli, faecal enterococci, Staphylococcus aureus, F-specific RNAphages, enteroviruses (1993 and 1994) and for thermophilic Campylobacter, Salmonella, Aeromonas, Plesiomonas shigelloides and Pseudomonas aeruginosa (1993). The samples taken in the weeks before the exposure showed significant differences in thermotolerant coliform concentration between locations, depths and times. Also during swimmer exposure, significant differences occurred in microorganism levels at the different sampling points over the swimming course. As the triathletes swam as a group, they were exposed to approximately the same water at the same time. The geometric mean concentration was used to characterise each site. In the epidemiological study, the risk of an intestinal infection correlated with the concentration of thermotolerant coliforms and E. coli but not with the other parameters. The geometric mean concentration of thermotolerant coliforms at the triathlons ranged from 11–330/100mL and 54–1,200/100mL E. coli. Ranking of the seven sites by faecal pollution level, based on the geometric mean concentration of a faecal indicator, resulted in a different ranking for each indicator. At the fresh water sites studied, only the ratio between the geometric mean density of E. coli and thermotolerant coliforms was constant. The ratio between the other parameters related to faecal pollution (faecal enterococci, F-specific RNA phages, enteroviruses) varied considerably. Water quality standards relating to faecal pollution can only be based on parameters that show a significant correlation with risk of intestinal illness.

149 Evaluation of Hammermill Tip Speed, Air Assist, and Screen Hole Diameter on Ground Corn Characteristics

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 134-135
Author(s):  
Michaela B Braun ◽  
Kara M Dunmire ◽  
Michael Sodak ◽  
Jerry Shepherd ◽  
Randy Fisher ◽  
...  
Keyword(s):  
Particle Size ◽  
Geometric Mean ◽  
Air Flow ◽  
Hole Diameter ◽  
Experimental Unit ◽  
Flow Index ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Composite Flow ◽  
Ground Corn

Abstract This study was performed to evaluate hammermill tip speed, assistive airflow and screen hole diameter on hammermill throughput and characteristics of ground corn. Corn was ground using two Andritz hammermills (Model: 4330–6, Andritz Feed & Biofuel, Muncy,PA) measuring 1-m in diameter each equipped with 72 hammers and 300 HP motors. Treatments were arranged in a 3 × 3 × 3 factorial design with 3 tip speeds (3,774, 4,975, and 6,176 m/min), 3 screen hole diameters (2.3, 3.9 and 6.3 mm), and 3 air flow rates (1,062, 1,416, and 1,770 fan RPM). Corn was ground on 3 separate days to create 3 replications and treatments were randomized within day. Samples were collected and analyzed for moisture, particle size, and flowability characteristics. Data were analyzed using the GLIMMIX procedure of SAS 9.4 with grinding run serving as the experimental unit and day serving as the block. There was a 3-way interaction for standard deviation (Sgw), (linear screen hole diameter × linear hammer tip speed × linear air flow, P = 0.029). There was a screen hole diameter × hammer tip speed interaction (P &lt; 0.001) for geometric mean particle size dgw (P &lt; 0.001) and composite flow index (CFI) (P &lt; 0.001). When tip speed increased from 3,774 to 6,176 m/min the rate of decrease in dgw was greater as screen hole diameter increased from 2.3 to 6.3 mm resulting in a 67, 111, and 254 µm decrease in dgw for corn ground using the 2.3, 3.9, and 6.3 mm screen hole diameter, respectively. For CFI, increasing tip speed decreased the CFI of ground corn when ground using the 3.9 and 6.3 mm screen. However, when grinding corn using the 2.3 mm screen, there was no evidence of difference in CFI when increasing tip speed. In conclusion, the air flow rate did not influence dgw of corn but hammer tip speed and screen size were altered and achieved a range of dgw from 304 to 617 µm.

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