Showing papers by "University of Arkansas published in 1995"

Electromagnetically induced transparency in ladder-type inhomogeneously broadened media: Theory and experiment

Abstract: We develop a theory of electromagnetically induced transparency in a three-level, ladder-type Doppler-broadened medium, paying special attention to the case where the coupling and probe beams are counterpropagating and have similar frequencies, so as to reduce the total Doppler width of the two-photon process. The theory is easily generalized to deal with the \ensuremath{\Lambda} configuration, where the ideal arrangement involves two copropagating beams. We discuss different possible regimes, depending on the relative importance of the various broadening mechanisms, and identify ways to optimize the absorption-reduction effect. The theory is compared to the results of a recent experiment (on a ladder-type system), using the Rb D2 line, with generally very good agreement. The maximum absorption reduction observed (64.4%) appears to be mostly limited by the relatively large (\ensuremath{\sim}5 MHz) linewidth of the diode lasers used in our experiment.

Measurement of Dispersive Properties of Electromagnetically Induced Transparency in Rubidium Atoms

Abstract: The dispersive properties of the atomic transition in the rubidium ${D}_{2}$ line ($5{S}_{\frac{1}{2}}\ensuremath{-}5{P}_{\frac{3}{2}}$) at 780.0 nm are measured with a Mach-Zehnder interferometer when an additional coupling field at 775.8 nm is applied to an upper transition ($5{P}_{\frac{3}{2}}\ensuremath{-}5{D}_{\frac{5}{2}}$). This ladder-type system is observed to exhibit electromagnetically induced transparency together with a rapidly varying refractive index. A reduction in group velocity for the probe beam (${v}_{g}=\frac{c}{13.2}$) is inferred from the measured dispersion curve with 52.5% suppressed absorption on resonance.

Antioxidant systems in insects

Abstract: Insects possess a suite of antioxidant enzymes and small molecular weight antioxidants that may form a concatenated response to an onslaught of dietary and endogenously produced oxidants. Antioxidant enzymes such as superoxide dismutase, catalase, glutathione transferase, and glutathione reductase have been characterized in insects. Water-soluble and lipid-soluble antioxidants such as ascorbate, glutathione, tocopherols, and carotenoids have not been well studied in insects but may play very important antioxidant roles. Additionally, the peritrophic matrix and trehalose may possess important antioxidant functions in insects. The enzymatic recycling of ascorbate, first noted in green plants, may also exist in insects. A greater understanding of these antioxidant systems may provide greater understanding about the ecological relationships of insects with their hosts.

Foliar oxidative stress and insect herbivory: Primary compounds, secondary metabolites, and reactive oxygen species as components of induced resistance.

Abstract: Oxidative responses of plants to pathogens and other environmental stresses have received considerable recent attention. We propose that an oxidative response also occurs following attack by herbivores. Our data strongly indicate a shift in the oxidative status of soybean following herbivory by the insectHelicoverpa zea. Herbivory caused significant increases in lipid peroxidation and ·OH radical formation. The activity of several oxidative enzymes including lipoxygenases, peroxidase, diamine oxidase, ascorbate oxidase, and NADH oxidase I increased after herbivory on soybean. The enhanced production of phenolic compounds is indicated by an increase in the activity of phenylalanine ammonia lyase in wounded tissues. On the other hand, the level of soybean foliar antioxidants such as ascorbic acid, total carotenoids, nonprotein thiols, and catalase decreased significantly following herbivory. These results implicate primary compounds (e.g., ascorbic acid, proteins), secondary metabolites (e.g., phenolics), and reactive oxygen species (e.g., hydroxyl radical, hydrogen peroxide) as multiple components of induced resistance. The oxidative changes in the host plant correspond with increased oxidative damage in the midgut of insects feeding on previously wounded plants. Decreases in nonprotein thiols and reduced ascorbic acid occurred in midgut epithelial tissue from insects feeding on wounded plants compared to the insects on control plants. In contrast, midgut hydroperoxides and dehydroascorbic acid concentrations were greater in insects on wounded plants compared to their counterparts on control plants. We conclude that oxidative responses in soybean may have both positive and negative effects upon the host plant: a decrease in herbivory and an increase in oxidative damage to the plant. The salient benefit to the plant, in terms of insect resistance, is the relative balance between these opposing effects.

Self-Checking and Fault-Tolerant Digital Design

Abstract: Chapter 1 - Fundamentals of Reliability Chapter 2 - Error Detecting and Correcting Codes Chapter 3 - Self-Checking Combinational Logic Design Chapter 4 - Self-Checking Checkers Chapter 5 - Self-Checking Sequential Circuit Design Chapter 6 - Fault-Tolerant Design Appendix Markov Models

Observation of two-dimensional steady-state photorefractive screening solitons

Abstract: The first observation of two-dimensional steady-state photorefractive solitons is reported. Application of an electric field of 5.8 kV/cm to strontium barium niobate yields solitons with diameters as small as 9.6 mu m at microwatt power levels. >

Alkali-modified soy protein with improved adhesive and hydrophobic properties

Abstract: Adhesive and hydrophobic properties of alkalimodified soy protein (AMSP) and trypsin-modified soy protein (TMSP) on wood were investigated. Modifying soy protein (i) under moderate alkaline conditions (pH 10.0 at 50°C) and (ii) with trypsin, enhanced adhesive strengths (730 and 743 N, respectively) compared with unmodified soy protein (340 N). Hydrophobicities of AMSP, TMSP, and unmodified soy protein isolate by sodium dodecyl sulfate binding and 1-anilino-8-naphthalene sulfonate methods were 7.6, 6.4, 5.0 and 39, 27, 13, respectively. Modified soy protein adhesives with higher hydrophobicities (AMSP and TMSP) had enhanced water-resistance properties.

Endophyte infection effects on stomatal conductance, osmotic adjustment and drought recovery of tall fescue

Abstract: summary Presence of the endophytic; fungus Acremonium coenophialum Morgan-Jones and Gams in tall fescue (Festuca artuidinacea- Sehreb.) enhances host persistence in drought-prone environments. However, the physiological mechanism is not well understood. We investigated the influence of endophyte infection and water deficit on osmotic adjustment, stomatal conductance, tiller survival and leaf elongation rate of genotype GA87-122 and cv. Kentucky-31 (KY31) of tall fescue. Plants were grown in a greenhouse in pots containing fine-silty topsoil (experiment 1) or sand (experiment 2). In expt 1, endophyte-infected (EI) and endophyte-free (EF) isolines of GA87-122 were exposed to two drought preconditioning cycles, after which all pots were re-watered and osmotic adjustment determined. Osmotic adjustment was −0.46 and −0.51 MPa in El leaf blades and tiller bases and −0.29 and −0.13 MPa in EF leaf blades and tiller bases, respectively. In expt 2, EI and EF GA87-122 and KY31 Mere exposed to severe drought after two preconditioning cycles, then re-watered. During the second preconditioning drying cycle of KY31, stomatal conductance tended to be lower in EI than in EF plants, but the difference was significant (P 0–05) only at two sampling times. Shoot tissues osmotically adjusted 0.17–0.31 MPa more in EI than in EF plants. Tiller survival and leaf elongation rates were higher (P 0.05) in preconditioned EI than in EF plants. Basal-zone osmotic adjustment was correlated with tiller survival rate in GA87-122 and KY31 (r = 0.87, P 0.01 for both). Enhanced osmotic adjustment in the meristematic and growing zone might account far improved survival of tillers by facilitating protection of the apical meristem.

An Investigation of the Dynamic Relationship between Agency Theory and Dividend Policy

Abstract: Agency theory posits that the dividend mechanism provides an incentive for managers to reduce the costs associated with the principal/agent relationship. Distributing resources in the form of cash dividends forces managers to seek outside capital, thus causing them to reduce agency costs as they subject themselves to the scrutiny of the capital marketplace. Under this scenario the optimum level of dividend payout is that which minimizes the agency cost structure relative to the cost of raising needed funds. A test of this theory employing time-series cross-sectional analysis and more direct measures of the agency cost structure shows that these tenets of agency theory may be valid. Managers do appear to adjust the dividend payout in response to the agency cost/transaction cost structure, both through time as well as across firms.

Household Demand in Rural China: A Two-Stage LES-AIDS Model

Abstract: A complete demand system of Chinese rural households is estimated using a two-stage LES-AIDS model and pooled provincial and time-series data from 1982 to 1990. For commodity groups (food, clothing, fuel, housing, and other commodities), demand is price-inelastic. Housing and other commodities are luxury goods, while clothing and food are necessities. Within the food group, price elasticities range from −0.005 to −0.63. Expenditure elasticities are lower for grains and higher for meat, tobacco, and alcohol. The results imply a gap between food demand and supply growth. Therefore, China will face pressure to import food.

Electromagnetically induced transparency in a three-level Λ-type system in rubidium atoms

Abstract: An electromagnetically induced transparency is observed at one arm of a three-level \ensuremath{\Lambda}-type system in a rubidium D1 line (794.8 nm) with an 85% reduction in absorption, when a pumping field is present at the other arm. This reduction in absorption for the weak probe field is due to the atomic coherence produced by the strong pumping field. This experiment is done in a Rb vapor cell at room temperature with cw diode lasers for both pumping and probe beams in a Doppler-free configuration. A simple theoretical treatment including Doppler broadening is in good qualitative agreement with the experimental measurement.

Heat-resistance of Escherichia coli O157:H7 in meat and poultry as affected by product composition

Abstract: The effects of fat level and low fat formulation on survival of Escherichia coli O157 :H7 isolate 204P heated in ground beef [7%, 10% and 20% fat], pork sausage [7%, 10%, and 30% fat], chicken (3% and 11% fat), and turkey (3% and 11% fat) were determined by D- and z-values. D-values for E. coli O157 :H7 in lowest fat products were lower than in traditional beef and pork products (P < 0.05). Overall, higher fat levels in all products resulted in higher D-values. D 60 values (min) ranged from 0.45-0.47 in beef, 0.37-0.55 in pork sausage, 0.38-0.55 in chicken and 0.55-0.58 in turkey. D 55 and D 50 values were respectively longer. Z-values ranged from 4.4-4.8°C. Product composition affected lethality of heat to E. coli O157 :H7.

Fruit Preferences of Four Sympatric Primate Species at Ketambe, Northern Sumatra, Indonesia

Abstract: Recent researchers have drawn attention to fruit preferences in a variety of primates;for instance, in 1991, Davies noted that monogastric primates prefer the flesh of succulent, sugar-rich fruits, while colobines more often consume and digest large seeds of drier fruits. I compare fruit preferences in four sympatric primates— Hylobates lar, Macaca fascicularis, Pongo pygmaeus,and Presbytis thomas—which I studied concurrently at the Ketambe Research Center in northern Sumatra. I collected continuous focal animal data during 40–50 hr per taxon per month for 10 months and recorded fruit species size,pH, and descriptive attributes, including degree of ripeness, hardness, pericarp type, and number of seeds. The langurs prefer dry fruit seeds while the monogastric primates more often consume acidic, succulent fruit flesh. Further, H. lar, M. fascicularis,and P. pygmaeusvary significantly in preferences for fruits vis-a-visthe characteristics examined.

Forums for management information systems scholars

Abstract: hat is " scholarly nzsearch " and which pub& cation outlets are considered 'best " ? In any academic discipline, the answers to these questions ate sought by:. Selection, promotion, and tenure committees as they seek to secure and retain the best possible individuals for thar faculty [5,151; l Researchers, as they seek to determme appropriate outlets for their research findings [5,6, 151; l Individuals seelung to identify the significant research streams in an academxc disciphne [25]; l Journal editors and assoaates as they seek to raise the quality of their journal to the highest possible l&l; I l The academic discipline in question as it seeks to gain an identity of its own, especially if it is a relatively young field [ 11, 251; l Students of the discipline as they seek to gain an understanding of what the discipline encompasses [6, 11,251; and l Librarians as they seek to wisely invest their ever-decreasing funds. Borrowing from the vernacular of consumer behavior theory, these constituents all have an interest in the " consumption " of knowledge. As with any consumption decision, limited resources dictaw that decisions be made concerning which " products " to consume. Thus, in the academic setting, this consumption decision concerns determining the bestjournals to further the discipline [15]. From the demand perspective, consumers of knowledge (e.g., researchers, individuals interested in the field, libraries) wish to invest their time and money economically, consuming the best material possible. On the supply side, producers of knowledge (e.g., researchers,journal editors, associates) wish to produce material that best meets consumer demand. Thus, many constituents have a definite interest in the determination of the relevance of publication outlets in a particular discipline. This study was undertaken to determine the important publishing journals and/or other outlets for management information systems (MIS) faculty. The MIS faculty were viewed as expert consumers of MIS research. In particular, three dimensions of each expert's background were considered important: the expert's education, role orientation, and academic lifestyle. The impact of these dimensions was studied to determine their influence on MIS faculty perception of publishing journals. Finally, presenting the results within an analytically sound framework will permit future researchers in MIS forums to use this study's model to better present their findings. Previous pertinent research done on potential MIS research forums and factors influencing their results are assessed and discussed in the following subsections. In 1983, Hamilton and …

Waveguides formed by quasi-steady-state photorefractive spatial solitons

Abstract: We show that a quasi-steady-state photorefractive spatial soliton forms a waveguide structure in the bulk of a photorefractive material. Although the optically induced waveguide is formed by a very low-power (microwatts) soliton beam, it can guide a powerful (watt) beam of a longer wavelength at which the medium is nonphotosensitive. Furthermore, the waveguide survives, either in the dark or when guiding the longer-wavelength beam, for a long time after the soliton beam is turned off. We take advantage of the solitons’ property of evolution from a relatively broad input beam into a narrow channel and show that the soliton induces a tapered waveguide (an optical funnel) that improves the coupling efficiency of light into the waveguiding structure.

Digital control for switching converters

Abstract: In this paper, several different techniques for designing discrete controllers for switching power converter applications are presented. Simulation results are also provided for illustration purposes.

Uniting Critical Theory and Public Policy to Create the Reflexively Defiant Consumer

Abstract: Postmodern extensions of critical theory are used to explore traditional notions of consumer education. Generally, marketing researchers, consumerists, and policymakers have emphasized the importance of making the consumer critical through providing consumers with more complete information and better skills. However, this focus on improving consumers' decision making leaves the existing system virtually unquestioned and intact. An alternative vision of a critical consumer is offered. The authors suggest that consumers must become more radically critical or reflexively defiant by dropping this natural attitude toward the existing order and, instead, questioning economic, political, and social structures. This article attempts to create a new discourse for consumers and suggests that public policy can help consumers become aware of their power to define and fulfill their own needs.

Dust accumulation in the canopy: a potential cause of dental microwear in primates.

Abstract: Dental microwear researchers consider exogenous grit or dust to be an important cause of microscopic wear on primate teeth. No study to date has examined the accumulation of such abrasives on foods eaten by primates in the forest. This investigation introduces a method to collect dust at various heights in the canopy. Results from dust collection studies con- ducted at the primate research stations at Ketambe in Indonesia, and Haci- enda La Pacifica in Costa Rica indicate that 1) grit collects throughout the canopy in both open country and tropical rain forest environments; and 2) the sizes and concentrations of dust particles accumulated over a fixed period of time differ depending on site location and season of investigation. These results may hold important implications for the interpretation of microwear on primate teeth. o 1995 Wiley-Liss, Inc.

Benefits and Costs of Defense in a Neotropical Shrub

Abstract: Benefits and costs are central to optimality theories of plant defense. Benefit is the gain in fitness to reducing herbivory and cost is the loss in fitness to committing resources to defense. We evaluate the benefits and costs of defense in a neotropical shrub, Psychotria horizontalis. Plants were either exposed to herbivores or protected within a cage of fine mesh in three gardens planted in large light gaps on Barro Colorado Island, Panama. Two cuttings of each of 35 clones were paired based on initial masses and assigned randomly to a garden and to either the exposed or protected treatment. Annual rates of herbivory were 37% for exposed plants and 17% for protected plants. Among the exposed plants, high tannin concentration and tough leaves reduced herbivory. Twenty months after plant- ing, the protected plants had a 10-fold higher growth rate, and 5.5 times more leaf area and dry mass than the protected plants. Twenty-two percent of the protected plants flowered, whereas no exposed plants flowered. Within the protected treatment, both total tannin concentration and leaf toughness varied among clones, which suggests that these traits are heritable. Total tannin concentration, but not toughness, was negatively correlated with growth for protected plants, which implies a cost to producing tannins. High tannin con- centration and tough leaves reduced herbivory, however, these benefits of defense were balanced by the costs such that there were no significant differences in growth among exposed plants. These results are consistent with the hypotheses that there are benefits to being defended, that defense can be costly, and that herbivores act as selective agents in the evolution Qf plant defense.

Dark photorefractive spatial solitons and photorefractive vortex solitons.

Abstract: We report on the first experimental observations of dark, planar, spatial photorefractive solitons, and photorefractive vortex solitons that are trapped in a bulk (three-dimensional) photorefractive media. Both the dark and vortex solitons possess the ``signatures'' of the photorefractive solitons: they are independent of absolute intensity, can afford significant absorption, and are inherently asymmetric with respect to the transverse dimensions of trapping.

An exploratory study into the purchase decision process used by leisure travelers in hotel selection.

Abstract: The purchase decision process used by leisure travelers in the selection of hotel accommodations is quite complex. This research, although exploratory in nature, empirically investigates the relationships among various cues hypothesized to impact purchase decisions. Cues used by leisure travelers in the evaluation of the more "intangible" purchase criteria of security, dependability, service quality, convenience, and reputation were identified. Based on the findings, the authors identified marketing and promotional strategies appropriate for retaining current customers and attracted new customers.

Interferon-gamma exerts its negative regulatory effect primarily on the earliest stages of murine erythroid progenitor cell development.

Abstract: Interferon-gamma (INF-gamma) has been shown to suppress erythropoiesis and perhaps to contribute to the anemia of chronic disease. In this study we demonstrated that the concentration of INF gamma required to suppress murine burst forming unit-erythroid (BFU-E) growth was significantly less than that required to suppress colony forming unit-erythroid (CFU-E) growth. INF gamma acted at the most primitive step in erythroid progenitor cell differentiation and proliferation, as inhibition was maximal when added at the time of BFU-E culture initiation. Inhibition was progressively less if INF gamma addition was delayed after culture initiation. The effects of INF gamma on BFU-E did not require the presence of interleukin-1 alpha (IL-1 alpha), tumor necrosis factor-alpha (TNF alpha), or granulocyte macrophage colony stimulating factor (GM-CSF), as its effects were not neutralized by monoclonal antibodies against IL-1 alpha, TNF alpha, or GM-CSF. This applied whether INF gamma was added to culture with individual antibodies or with a combination of all three antibodies. INF gamma was not required for IL-1 alpha- or TNF alpha-induced suppression of BFU-E, as their effects were not neutralized by a monoclonal anti-INF gamma antibody. In contrast, GM-CSF-induced suppression of BFU-E was negated by the simultaneous addition of anti-INF gamma. We have previously shown that the addition of TNF alpha does not suppress BFU-E growth in cultures from marrow depleted of macrophages. Suppression did occur, however, if a small concentration of INF gamma that does not inhibit and increasing concentration of TNF alpha were added to culture, suggesting a synergistic effect between INF-gamma and TNF alpha. These observations suggest that INF gamma is a potent direct inhibitor of erythroid colony growth in vitro. It exerts its negative regulatory effect primarily on the earliest stages of erythroid progenitor cell differentiation and proliferation, as much higher doses are required to suppress late erythroid cell development. INF gamma is also involved in GM-CSF-induced inhibition of BFU-E colony growth.

Modification of soy proteins and their adhesive properties on woods

Abstract: Adhesive properties of trypsin-modified soy proteins (TMSP) on woods were investigated. A simple method developed in our laboratory, consisting of measuring the force required to shear the bond between glued wood pieces in the Instron universal testing machine, was used to examine adhesive strength of modified soy proteins on wood. Adhesive strength of TMSP was measured for cold-pressed (ambient temperature for 2 h) and hot-pressed (60, 80, 100, and 120°C for times varying from 0.5 to 2.5 h) woods. Of the woods examined, soft maple gave the highest strength [743 Newtons (N) at a protein glue concentration of 2 mg/cm2]. For soft maple and cold-pressing, TMSP at 2 mg/cm2 gave twice the adhesive strength of unmodified protein controls, 743 vs. 340 N. Also, the adhesive strength of TMSP increased from 284 to 743 N as glue concentration was increased from 1 to 2 mg/cm2. However, hot-pressing of wood pieces beyond 1 h at 120°C and 30% relative humidity resulted in decreased adhesive strengths of TMSP compared to controls. Further, adhesive strengths of hot-pressed glued wood samples decreased when the relative humidity at which they were kept for curing increased from 30 to 60%. This negative effect of increased humidity on adhesive strengths of glued wood pieces was not observed with cold-pressed TMSP.

Words and Deeds: Foreign Assistance Rhetoric and Policy Behavior in the Netherlands, Belgium, and the United Kingdom

Abstract: Alternative hypotheses involving self-interested versus benevolent motives have played an important role in the study of foreign assistance policy behavior. Most often, such studies infer motives from data regarding the foreign assistance expenditures of a donor state. This study moves beyond such inferences. First, donor self-interest can take different forms that are likely to be expressed in different policies. Second, inferences about motivation derived from aid expenditure data infer motives from the observation of actions only. This study seeks to address both points. First, it proposes a typology of aid motivation. Second, it proposes separate indicators of motivation and behavior. The proposed national role conception framework hypothesizes that certain motivations, as expressed in rhetoric, and certain behaviors, as expressed in the foreign assistance expenditures, co-vary. The study focuses on the foreign assistance debate in and policy behavior of the Netherlands, Belgium, and the United Kingdom. It finds that there is a congruence between the rhetoric and policy behavior of the foreign assistance decision makers of the Netherlands and the United Kingdom, but that the Belgian data lack such congruence.

Chemical and physical studies of type 3 chondrites XII: The metamorphic history of CV chondrites and their components

Abstract: The induced thermoluminescence (TL) properties of 16 CV and CV-related chondrites, four CK chondrites and Renazzo (CR2) have been measured in order to investigate their metamorphic history. The petrographic, mineralogical and bulk compositional differences among the CV chondrites indicate that the TL sensitivity of the approximately 130 C TL peak is reflecting the abundance of ordered feldspar, especially in chondrule mesostasis, which in turn reflects parent-body metamorphism. The TL properties of 18 samples of homogenized Allende powder heated at a variety of times and temperatures, and cathodoluminescence mosaics of Axtell and Coolidge, showed results consistent with this conclusion. Five refractory inclusions from Allende, and separates from those inclusions, were also examined and yielded trends reflecting variations in mineralogy indicative of high peak temperatures (either metamorphic or igneous) and fairly rapid cooling. The CK chondrites are unique among metamorphosed chondrites in showing no detectable induced TL, which is consistent with literature data that suggests very unusual feldspar in these meteorites. Using TL sensitivity and several mineral systems and allowing for the differences in the oxidized and reduced subgroups, the CV and CV-related meteorites can be divided into petrologic types analogous to those of the ordinary and CO type 3 chondrites. Axtell, Kaba, Leoville, Bali, Arch and ALHA81003 are type 3.0-3.1, while ALH84018, Efremovka, Grosnaja, Allende and Vigarano are type 3.2-3.3 and Coolidge and Loongana 001 are type 3.8. Mokoia is probably a breccia with regions ranging in petrologic type from 3.0 to 3.2. Renazzo often plots at the end of the reduced and oxidized CV chondrite trends, even when those trends diverge, suggesting that in many respects it resembles the unmetamorphosed precursors of the CV chondrites. The low-petrographic types and low-TL peak temperatures of all samples, including the CV3.8 chondrites, indicates metamorphism in the stability field of low feldspar (i.e., less than 800 C) and a metamorphic history similar to that of the CO chondrites but unlike that of the ordinary chondrites.

Mapping the Sw-5 locus for tomato spotted wilt virus resistance in tomatoes using RAPD and RFLP analyses

Abstract: The Sw-5 locus confers dominant resistance to tomato spotted wilt virus (TSWV). To map the location and facilitate the identification of markers linked to Sw-5 we developed a pair of near-isogenic lines (NILs) and an F2 Lycopersicon esculentum x L. pennellii population segregating for resistance to TSWV. DNA from the NILs was analyzed using 748 random 10-mer oligonucleotides to discern linked molecular markers using a random amplified polymorphic DNA (RAPD) approach. One random primer (GAGCACGGGA) was found to produce a RAPD band of about 2200 bp that demonstrates linkage to Sw-5. Data from co-segregation of resistance and restriction fragment length polymorphisms (RFLPs) in a F2 interspecific population position Sw-5 between the markers CT71 and CT220 near the telomere of the long arm of chromosome 9.

Protein Concentrates from Unstabilized and Stabilized Rice Bran: Preparation and Properties

Abstract: Protein concentrates were prepared from commercially available unstabilized and heat stabilized rice bran by alkaline extraction and isoelectric precipitation. Stabilized rice bran had lower protein extractability at all particle sizes (75μ to 150μ). Both unstabilized rice bran protein concentrate (URBPC) and stabilized rice bran protein concentrate (SRBPC) showed maximum nitrogen solubility at pH 8.0. URBPC (71.5% protein) and SRBPC (50.9% protein) showed differences in amino acid contents. SDS-PAGE of protein concentrates revealed several common components and absence of certain components from SRBPC. Protein denaturation due to commercial heat stabilization impaired extractability of proteins and influenced its quality.

Circadian rhythmometry of serum interleukin-2, interleukin-10, tumor necrosis factor-alpha, and granulocyte-macrophage colony-stimulating factor in men.

Abstract: Serum levels of four cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-10 (IL-10)] were measured in nine diurnally active healthy adult male subjects at 3-h intervals during a 24-h period. Statistical evaluation by analysis of variance and/or the least- squares fit of a cosine model revealed significant 24-h rhythms for each cytokine. Although the amount of IL-2 in the serum was low, the levels fluctuated to form a single peak at approximately noon. In contrast, the other three cytokines exhibited a biphasic temporal pattern. In subjects with detectable TNF-alpha levels, the first peak occurred at 07:30 and the second at 13:30. IL-10 levels also exhibited a biphasic pattern, with one peak at 07:30 and the second 12 h later at 19:30. GM-CSF levels were last to rise, first peaking at approximately 13:30 and then again at 19:30. These results suggest temporal patterns that are unique for each cytokine, generally with daytime highs and nighttime lows.