Percent Purity Research Articles

Human dendritic cells. Enrichment and characterization from peripheral blood.

Previous studies demonstrated that lymphoid tissues of mice and rats contain small numbers (less than 1 percent of nucleated cells) of dendritic cells (DC) with special cytologic, surface, and functional properties. We show here that similar DC represent 0.1-0.5 percent of human peripheral blood mononuclear cells. DC can be enriched to 20-60 percent purity by a multistep procedure analogous to that used in mice. Adherent peripheral blood mononuclear cells are cultured overnight, and the released cells are depleted of monocytes and B cells by readherence to plastic, rosetting with erythrocytes coated with anti-human IgG, and centrifugation in dense albumin columns. Enriched DC have similar cytologic features to rodent DC by light and electron microscopy. DC express HLA, and HLA-DR and the leukocyte-common antigens. They lack phagocytic capacity, receptors for antibody-coated and neuraminidase-treated erythrocytes, surface and intracellular Ig, esterase, peroxidase, and azurophilic granules. DC do not react with several monoclonal antibodies directed to phagocytes (OKM 1, "mac-1," 63D3, and 61D3) and T cells (OKT 3, 6, 8). Unlike the mouse, human DC express complement receptors. When maintained in culture for 4 d, human DC did not give rise to either B cells or monocytes. Therefore, DC identified by cytologic criteria are distinct from other leukocytes. Enriched populations of DC have been compared to fractions enriched in monocytes, B cells, and T cells in three functional assays: stimulation of the primary allogeneic mixed leukocyte reaction, stimulation of the primary syngeneic MLR, and accessory function for the proliferation of periodate- modified T cells. In each case, the DC fraction was 10-fold or more active than other cell fractions. We conclude that DC circulate in man, and represent the principal cell type required for the initiation of several immune responses.

Freezing Cold‐tolerant Parental Clones of Sugarcane1

AbstractSugarcane (a complex hybrid of Saccharum spp.) deteriorates after freezing damage. Efforts have been made to introduce the cold tolerance of S. spontaneum L. into commercial types. Six cold‐tolerant clones of F1 (commercial cultivar ✕ S. spontaneum) and BC1 progenies were used to evaluate the deterioration of Sugarcane after artificial freezing and to compare the deterioration characteristics of their crusher juice quality with those of two commercial cultivars. The characteristics of juice quality studied were pH, titratable acidity, percent sucrose, percent purity, and kg of sugar per metric ton of cane. Stalks were exposed to −4.4 to −5.0 C for 6 hours. Samples were ground at Week 0 (immediately after harvest) and at 1, 2, and 3 weeks after freezing. The juice of fresh cane, Week 0, of the six cold‐tolerant clones had higher pH and titratable acidity and lower percent sucrose, percent jurity, and kg of sugar per metric ton of cane than did that of either commercial cultivar (‘CP 57‐526’ or ‘CP 63‐588’). Low positive correlations between titratable acidity measurements made at the start and end of various time periods after freezing of sugarcane stalk samples indicate that the deterioration hi titratable acidity between sampling dates was either independent or associated in a loose manner. Titratable acidity for all six cold‐tolerant clones increased relatively slowly during the first 2 weeks after freezing. Titratable acidity after freezing is more indicative of cold damage than is percent sucrose, and selecton of clones for cold tolerance might be made more rapidly if titratable acidity were used as the selection criterion.

Resistance to Airflow of Bluestem Grass Seed

ABSTRACT THE airflow resistance of Bluestem grass seed was measured for three different harvest dates at 17 to 79 percent MC, 10 to 17 percent purity, and 50 to 120 kg/m3 bulk density and compared with 63 percent purity seed stored from a previous crop. In a plot of Shedd's equation, bulk density was found to influence the slope and moisture content the intercept value. Purity in-fluences bulk density, which is the major parameter affecting airflow resistance.

Post‐Freeze Deterioration of Six Sugarcane Cultivars1

AbstractSugarcane (a complex trispecies hybrid, Saccharum spp) deteriorates following a killing freeze resulting in decreased sugar recovery with time. When the freeze is severe, sugarcane becomes unmillable. Cultivar differences in deterioration rates following freezes have been reported but most modern sugarcane cultivars have not been tested under field conditions. The main objective of this study was to compare the deterioration rates of six sugarcane cultivars during a 9‐week period following severe freezes at Belle Glade, Fla. 18 to 20 Jan. 1977. Samples of ‘CP 57‐603’, ‘CP 68‐1026’, CP 65‐357', CP 68‐1067', ‘Cl 41‐223’, and ‘CP 63‐588’ were randomly selected from the plots of a randomized complete block experiment each week. Brix, raw juice pH, titratable acidity, stalk weight, and juice polarization were measured. Theoretical yield of sugar per metric ton of cane, percent juice sucrose, percent purity, and sugar loss with time were obtained by standard calculations. Deterioration rates were estimated by regression of sugar parameters with time. All cultivars deteriorated rapidly and linearly over the 9‐week period following three nights of freezes (the lowest temperature was −6 C). The average loss in theoretical sugar yield was 13 kg of suagr/metric ton of cane/week. The rate of deterioration for the 9‐week period, as gauged by the data collected, was lowest for CP 65‐357. During the first 5 weeks following the freezes, theoretical sugar yield and purity were highest for CP 63‐588; however, during the final weeks of the experiment, juice quality was highest for CP 65‐357. The mean loss of sugar for all cultivars was 9.2% per week.

Influence of Nitrogen Fertility Level and Topping Method on Yield, Quality, and Storage Losses in Sugarbeets1

AbstractThe recovery of sucrose from sugarbeets (Beta vulgaris L) has decreased in recent years while root yield has increased. Our objective was to determine the effect of N application rate and topping method on root yield and on the factors affecting recovery of sucrose‐sucrose content, purity, and storage loss.The effect of five N fertility levels (0, 67, 134, 202, and 269 kg/ha) on sugarbeet root yield, quality (percent sucrose and percent purity) and crown tissue size was investigated from 1975‐1977 in 10 field experiments in Colorado, Kansas, and Nebraska. Crown tissue, the portion of the sugarbeet above the lowest leaf scar, increased from 10.64 to 16.03% of the total root weight as the N application rate increased from 0 to 260 kg/ha. Total root yield increased from 45.2 to 54.4 metric tons/ha over the same N range, but much of the yield increase was due to increase in crown size. Sucrose content and clarified juice purity (CJP) decreased 1.42 and 1.97% units, respectivdy, as the N application went from 0 to 269 kg/ha. The decrease in quality offset the increase in yield so that increasing rates of N had no significant effect upon yield of recoverable sucrose per ha. The extractable sucrose per metric ton of beets was reduced from 144.5 kg/ton for the 67 kg N/ha application to 128.6 kg/ton for the 269 kg N/ha application. Crown removal significantly reduced yield of recoverable sucrose per hectare but only increased extractable sucrose per ton from 136.7 to 140.0 kg/ton.Quality (sucrose and CJP) was improved both by proper topping and by N management, however, N management has a more dramatic effect upon quality. Total sucrose yield is reduced by topping, but not significantly affected by N application rate.Three N fertility levels (0, 134, and 269 kg/ha) and three topping methods (flailed, half‐topped, and topped) were evaluated for their effect on sucrose and quality changes in sugarbeet roots during storage in nine experiments. Failed beets had 27.4 and 25.5% less gross sucrose and recoverable sucrose losses than regular topped beets and 17.3 and 15.7% less gross suaose and recoverable sucrose lass than half‐topped beets. Method of topping had a significant effect upon sucrose losses in beets grown in all Iri levels. Nitrogen application rate had no significant effect upon gross sucrose or recoverable sucrose losses.Beet quality (extractable sucrose per metric ton) was higher in topped beets than flailed beets at harvest, but no difference existed between topping treatments after storage. Sucrose production per acre and beet quality was maximized with the low fertility, flailed treatments before and after storage.

Characterization and localization of myosin in the brush border of intestinal epithelial cells.

The brush border of intestinal epithelial cells consists of a tightly packed array of microvilli, each of which contains a core of actin filaments. It has been postulated that microvillar movements are mediated by myosin interactions in the terminal web with the basal ends of these actin cores (Mooseker, M.S. 1976. J. Cell. Biol. 71:417-433). We report here that two predictions of this model are correct: (a) The brush border contains myosin, and (b) myosin is located in the terminal web. Myosin is isolated in 70 percent purity by solubilization of Triton-treated brush borders in 0.6 M KI, and separation of the components by gel filtration. Most of the remaining contaminants can be removed by precipitation of the myosin at low ionic strength. This yield is approximately 1 mg of myosin/30 mg of solubilized brush border protein. The molecule consists of three subunits with molecular weights of 200,000, 19,000, and 17,000 daltons in a 1:1:1 M ratio. At low ionic strength, the myosin forms small, bipolar filaments with dimensions of 300 X 11nm, that are similar to filaments seen previously in the terminal web of isolated brush borders. Like that of other vertebrate, nonmuscle myosins, the ATPase activity of isolated brush border myosin in 0.6 M KCI is highest with EDTA (1 mumol P(i)/mg-min; 37 degrees C), intermediate with Ca++ (0.4 mumol P(i)/mg-min), and low with Mg++ (0.01 mumol P(i)/mg-min). Actin does not stimulate the Mg-ATPase activity of the isolated enzyme. Antibodies against the rod fragment of human platelet myosin cross-react by immunodiffusion with brush border myosin. Staining of isolated mouse or chicken brush borders with rhodamine-antimyosin demonstrates that myosin is localized exclusively in the terminal web.

The Preparation of Calcium Superoxide at Subambient Temperatures and Pressures

We have previously reported on the preparation of calcium superoxide, Ca(O2)2, from calcium peroxide diperoxyhydrate, CaO2·2H2O2. In that work, the preparation of a product of higher purity than that reported elsewhere was ascribed to the carefully controlled reaction conditions. The effect of temperatures between 25° and 60°C (298–333 K), reaction time, and reactant packing were studied. In further experiments reported here, disproportionations at lower temperatures and a range of reaction chamber pressures were studied. Disproportionations at 0°C (273 K) and surface spreadings of 312 to 36 cm2/g resulted in 59–61 percent purity Ca(O2)2, showing that higher surface loadings could be used in the reaction dish at subambient temperature than at ambient temperature. This is a significant feature for prospective scale up of the mass prepared in a single experiment. Reactions were studied at chamber pressures between 6 μm and 300 mm Hg (0.8 Pa–40 kPa) at 30°C (303 K). The optimum pressure for product purity was 90 μm Hg (12 Pa), possibly because the reactant overheated at lower pressures. Product purity at higher pressures improved when molecular sieve desiccant was mixed with the reactant.

Interpretation and Practical Field Utilization of the Relationship between Brei Nitrate and Sugar Content of Sugarbeets

The adverse effect of excessive fertilizer nitrogen (N) on the quality (sugar content and percent purity) of sugarbeets has been well established over the years. In 1912, Headden (13)2 reported the depressing effect of N availability on quality. Very little attention was given to the subject for many years until 1942 when Gardner and Robertson (7) and Ulrich (21) showed that N reduced quality. Since 1942 , many reports have been published elucidating the in­ verse relationship between N fertility and quality. Major advances in the understanding of this relationship and reviews on the subject have been made periodically by many researchers (6, 9, 10, 14 , 16, 19,22) The majority of the early work was related only to N effect on sugar content. The adverse effect of excessive N availability on purity has only been studied extensively since the 1960's. Early work by Draycott and Cooke (5) and Adams (1) revealed that purity was decreased by the application of N from barnyard manure. Several researchers in the U.S. (8, 12 , 20) and Europe (3, 4, 17) have re­ ported that there is a 0.32%-0.47% decrease in purity for every 50 lb / A increment in N fertility level. Alexander (2) very eloquently stated, If one controllable factor can be singled out as affecting beet quality to the greatest extent, it most certainly would be nitro­ gen fertiliza tion . There has been a steady and continual decline in quality that has been associated with increased use of N fertilizer over the years. Before N fertilizers came into extensive use in 1937 , the average sugarbeet yield in the United States was 10.8 T / A with a sugar content of 16.19 %. By 1957, after the use of N fertilizer had be­ come an integral part of sugarbeet culture , yields had increased to

Título en español.

En el período comprendido entre 1962 y 1974 se llevaron a cabo 19 experimentos en la zona semiárida de regadío, en la que hay temporadas tanto de moderada como de copiosa precipitación, con el fin de avaluar el Paraquat (1, 1 dimetil-4,4-dipiridio-bis-dimetil sulfato) conocido comercialmente por Gramoxone (Chevron Chemical Co.) como agente desecante de la caña de azúcar. El compuesto de aplicó por avión en cantidades entre 0.5 y 4 pintas (.24 a 1.88 litros) por acre en un volumen de agua que fluctuó entre 4 y 32 galones (15.24 litros y 1.21 hectolitros) por acre. Las aplicaciones se hicieron entre 2 y 7 días antes de la quema previa al corte de la plantación. Con la aplicación de Paraquat se logró una quema mejor, la cual disminuyó significativamente (3.5%) la cantidad de paja en la caña cortada en los experimentos realizados de 1962 a 1970 y en 5.08% en los de 1974. El contenido de fibra en la caña cortada disminuyó 0.72%, como promedio, en 1974, lo cual representa una disminución significativa de 1.09% en los cuatro experimentos efectuados en Aguirre. Esto, a la vez, representa un aumento de cuatro libras (1.8 kg.) de azúcar recuperada por tonelada de caña molida. En general, los valores obtenidos en el contenido en sacarosa, Brix y pureza de los jugos no se afectaron en forma significativa por la desecación del follaje al usar 1 pinta en 8 galones de agua (.47 litro de Gramoxone en 30.28 litros) por acre, especialmente en los experimentos de 1974. El agente desecante fue más eficaz cuando se usó la cosechadora "V-cutter" que con la otra maquinaria diseñada para el corte mecanizado de la caña de azúcar.

Reduction in Sugarcane Trash by Desiccation with Paraquat1

AbstractIncomplete preharvest burning, due to a high moisture content of green tops, has increased the trash content of sugarcane in Puerto Rico, thus raising field harvest costs and decreasing sugar recovery in the factory. The present investigation was made to study the possible use of a chemical desiccant to obtain better preharvest burning in order to decrease the trash content of the cane.Ten fields of sugarcane (Saccharum officinarum L.) in irrigated, normal, and high rainfall areas were divided in half, and one half of each field was sprayed with 1.8 liters of Paraquat (1,1′‐dimethyl‐4,4‐dipyridiniumbis‐dimethyl sulfate, commercially known as Gramoxone) in 76 liters of water/ha, 1 week before preharvest burning of the field to reduce cane trash. Burning was more thorough in Paraquat‐treated fields giving trash and cane fiber reductions of 5.08 and 0.72%, respectively. Values for sucrose percent cane, Brix, and purity were not significantly affected by desiccant action. The method of harvesting influenced response to the desiccant; the V‐cutter having a higher reduction in percent trash than did the cut and load harvester. No differences due to plant crop or ratoon were observed.

Investigation of Freezing Temperatures of National Bureau of Standards Aluminum Standards.

The design of a high-precision furnace for investigating the freezing points of metals up to 700 °C or higher is described. The freezing points of aluminum samples of nominally 99.999 percent purity from two batches were compared in terms of the ratio R(Al)/R(TP), the ratio of the resistance of the platinum resistance thermometer at the aluminum freezing point to that at the triple point of water. The average standard deviation of measurements of the ratio R(Al)/R(TP) obtained on six specimens corresponds to ±0.40 mK, while the average standard deviations of R(Al) and R(TP) correspond to ±0.17 mK and ±0.14 mK, respectively. (The variations in the measurements of R(TP) are amplified by 3.4 in the ratio R(Al)/R(TP).) The spread of the mean R(Al)/R(TP) obtained for five out of the six specimens corresponds to 0.51 mK; the deviation of the mean R(Al)/R(TP) of the sixth specimen from the mean R(Al)/R(TP) of the five specimens corresponds to -1.31 mK. (The sixth specimen may have been contaminated during the assembly of the freezing-point cell or the original sample bar was inhomogeneous.) The results show that aluminum can provide a freezing point (near 660 °C) that is at least as reproducible as the freezing point of antimony (near 631 °C).

Predicting Double‐Cross Sugarbeet Hybrid Performance1

Thirty‐five double crosses, 15 single crosses, and six red beet top crosses were developed from six inbred lines and used to tesl; five methods of predicting double‐cross sugarbeet (Beta vulgaris L.) hybrid performance. The mean of the four nonparental single crosses of any double cross was found to be the most consistent method for predicting root yield and percent sucrose. Percent purity was best predicted by the mean of all six single crosses of the parents iinvolved in any double cross. However, predictive capabilities of five methods studied were not greatly different. There was little relationship between the correlation cofficients and the percentage of accurately predicted top performing hybrids.

Measured Enthalpy and Derived Thermodynamic Properties of Solid and Liquid Lithium Tetrafluoroberyllate, Li2BeF4, from 273 to 900 K.

The enthalpy of a sample of lithium tetrafluoroberyllate, Li2BeF4, of 98.6 percent purity was measured relative to 273 K at eleven temperatures from 323 to 873 K. Corrections were applied for the impurities and for extensive premelting below the melting point (745 K). The enthalpy and heat capacity, and the entropy and Gibbs free-energy function relative to the undetermined value of were computed from empirical functions of temperature derived from the data, and are tabulated from 273 to 900 K.

Measured Enthalpy and Derived Thermodynamic Properties of Alpha Beryllium Nitride, Be3N2, from 273 to 1200 K.

The relative enthalpy of a sample of alpha beryllium nitride, Be3N2, of 95 percent purity was precisely measured over the temperature range 273 to 1173 K using a drop calorimetric method. Corrections were applied for the impurities, and the resulting heat capacity-temperature function was required to join smoothly that from recent precise NBS adiabatic calorimetry which covered the range 20 to 315 K. The enthalpy, heat capacity, entropy, and Gibbs free-energy function were computed from empirical functions of temperature and tabulated from 273 to 1200 K.

Fatigue-crack propagation in a high-strength aluminum alloy

Fatigue-crack propagation experiments were carried out within the framework of linear-elastic fracture mechanics to examine the effect of water and its constituents on the rate of crack growth in a high-strength aluminum alloy over a range of test temperatures from 295 to 380° K. Dehumidified high-purity (99.9995 percent purity) argon was used as an inert reference environment. The results showed that water accelerated the rate of fatigue-crack propagation by about a factor of 10 in this temperature range, whereas dry oxygen and dry hydrogen had a negligible effect. They confirm the findings of Hartman, and Bradshaw and Wheeler that the cause for the large increase in the rate of crack growth is the formation of hydrogen gas at high pressure in the region ahead of the crack tip, driven in by the reaction of water with the-freshly created aluminum crack surfaces, as suggested by Broom and Nicholson. The results showed further that fatigue-crack propagation in water, as well as in the dry environments, is controlled by thermally activated processes, with apparent activation energies that depend strongly on the crack-tip stress-intensity parameter, ΔK. The rate controlling process appears to be that associated with the creation of new crack surfaces in the range of crack growth rates 10−6 to 10−5 inch per cycle. The strong dependence of the apparent activation energy on ΔK suggests that a careful study of the kinetics of fatigue-crack growth and of the crack growth laws is in order. Such a study should incorporate both the mechanical and chemical variables involved.

TheEffectofTemperatureonPhotochemical Oxidant Productionin a Bench Scale Reaction System

Hexene-1 of 99 mol percent purity was obtained from the Phillips Petroleum Company and was used as the olefin. Nitrogen dioxide was obtained from the Matheson Company. A gas phase reaction system was constructed which utilized one 72-liter pyrex flask as the reaction chamber and a similar flask as the surge chamber. Peak oxidant production approximately doubled for each 10 degree temperature increase. The rate increased sharply as the reaction temperature increased from 13.5 to 25 degrees Centigrade, then decreased slightly as the temperature increased to 35 degrees C. From these results it is concluded that the peak oxidant production occurring during the irradiation of olefin and nitrogen dioxide mixtures is dependent on the reaction temperature. The magnitude of this temperature effect is of the same order as that which would be predicted for a thermal reaction. 3 references, 5 figures, 1 table.

The Effect of Phosphorus Fertilization and Time of Application and Chemical Composition of Foliage and on Yield Sucrose Content and Percent Purity of Sugar beet Roots

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Studies on Various Light Sources Concerning the Evaluation and Differentiation of Red Wine Color. I

The ability of a panel to differentiate wines as to color has been tested, and it has been shown that extremely small differences in color characteristics as determined by tristimulus data can be differentiated by the panel. Definition of the McAdam unit was found to be erroneous under the conditions of this test. This is explainable by the fact that the color was from reflected and transmitted light rather than just reflected light as the McAdam units were originally designed to compare. Three light sources have been compared. It was found that fluorescent light of the type tested was significantly better than the daylight source for differentiation, while no significant differences were found between incandescent and fluorescent or incandescent and daylight sources. In testing for color preference changes with various light sources, if was found that the fluorescent light showed a one blend preference shift from the other two sources. Further studies are planned to study the effects of changes in percent brightness and percent purity without dominant wave length change, and the converse of this. Also, studies pertaining to the Webner-Fechner law will be made.

Purification and Properties of Ten Organic Sulfur Compounds-Second Series.

Ten organic sulfur compounds, 2-propanethiol, 1-butanethiol, 2-butanethiol, 2-thiapropane, 2-thiapentane, 3-methyl-2-thiabutane, thiacyclohexane, 2-methylthiophene, 3-methylthiophene and benzo(b)thiophene, were purified to at least 99.9 mole percent purity. In addition to the boiling point, freezing point and cryoscopic constant, the following properties were measured at 20, 25 and 30/sup 0/: density, viscosity, surface tension and refractive index for the r, C, D, e, v, F, and g lines. Derived functions including refractivity intercept, specific dispersion, molecular refraction, parachor and molecular volume, were calculated. Mass, infrared and ultraviolet spectra were determined, permitting some correlation of the effect of sulfur groupings on spectra. The stability of the compounds under storage conditions was investigated.

Temperature Dependent Creep in Zinc Crystals

Tensile creep measurements beginning in a tensile strain region of about 10−6 have been made upon a set of seven single crystals of zinc of 99.99+ percent purity. Measurements were made both by means of electrical resistance strain gauges and an optical lever system. Some of the measurements made in the latter apparatus lasted 100 hours or more, and in both systems, measurements were made at several temperatures. The creep results obtained in this work can be best described by the single empirical relation η=btmin which η is the shear strain, t is the time after completion of the application of stress to the crystal, and b and m are constants for a given creep test under given experimental conditions. It is found that b increases with the stress but does not vary greatly with temperature. The values of m are practically independent of stress but vary with temperature, and appear to fit best the equation, m=m0exp(−T0/T)in the temperature interval investigated. For these crystals T0 = 1580°K, m0=120, and the temperature at which m=1 is 58°C. Values of m>1 are interesting in dislocation theory.