Showing papers by "University of Arkansas published in 1986"

Orbital-invariant formulation and second-order gradient evaluation in MOller-Plesset perturbation theory

Abstract: Based on the Hylleraas functional form, the second and third orders of Moller-Plesset perturbation theory are reformulated in terms of arbitrary (e.g., localized) internal orbitals, and atomic orbitals in the virtual space. The results are strictly equivalent to the canonical formulation if no further approximations are introduced. The new formalism permits the extension of the local correlation method to Moller-Plesset theory. It also facilitates the treatment of weak pairs at a lower (e.g., second order) level of theory in CI and coupled cluster methods. Based on our formalism, an MP2 gradient algorithm is outlined which does not require the storage of derivative integrals, integrals with three external MO indices, and, using the method of Handy and Schaefer, the repeated solution of the coupled-perturbed SCF equations.

Method Versus Substance: How Strong are Underlying Relationships Between Job Characteristics and Attitudinal Outcomes?

Abstract: This study compared the relative strengths of the effects of method versus substance on relationships between job characteristics and attitudinal outcomes. Reports from both job incumbents and nonincumbents on job characteristics and job attitudes were compared for 509 employees of four organizations. Substantive relationships were observed between job characteristics and effort, supporting the job characteristics model. Common method effects, however, inflated relationships between job characteristics and affective outcomes, thereby supporting the social information processing model. Implications are discussed for other areas of organizational research that rely on single data sources.

Mythic evolution of “The new frontier” in mass mediated rhetoric

Abstract: This essay combines the concept of “rhetorical narration” with Kenneth Burke's dramatistic pentad to argue that definitional cultural myths are rhetorically meaningful in relation to social consciousness when both are viewed as evolving teleologically. It delineates two phases of change in America's frontier myth associated with the transformation of the pentadic term “scene” from land to space, as represented in recent space fiction films: a mythic disjunction resulting from pentadic inconsistency with the new scene, followed by mythic coherence resulting from pentadic change to establish consistency.

Antibiotic prophylaxis in high-risk head and neck surgery: one-day vs. five-day therapy.

Abstract: Patients who undergo major contaminated surgery of the head and neck benefit from perioperative antibiotic prophylaxis. This study was developed to determine if 5 days of antibiotic administration would be more effective than 1 day. A multi-institutional prospective randomized double-blind study was designed. Patients who were identified as requiring pedicled flap reconstruction were potential candidates for the study. Later, patients were randomly assigned to receive cefoperazone sodium for either 24 hours or 120 hours. In each case, the drug was administered intravenously, beginning 1 to 2 hours preoperatively and continued for the prescribed period. One hundred nine patients were evaluable. Fifty-three patients were assigned to 1 day of perioperative prophylaxis. Wound infection developed in ten patients (18.9%). Fifty-six patients were assigned to 5 days of perioperative antibiotic prophylaxis. Wound infection developed in 14 (25%) of these patients (P greater than .05). These data suggest that no beneficial effect from administration of antibiotics for longer than 24 hours postoperatively can be achieved in patients who undergo myocutaneous flap reconstruction.

Comparing traditional methods for selecting class intervals on choropleth maps

Abstract: The most common goal when classing data for choropleth maps is to create homogeneous classes which contain similar data values. None of the four traditional data classing methods examined here (quartile, equal interval, standard deviation, and natural breaks) consistently generalized the experimental data sets into homogeneous classes. These methods were most accurate for data sets with specific distributional characteristics, but none classed all of any type of distribution accurately. Only the optimization method produced reliable and accurate results for all of the experimental data.

Acetyl coenzyme A-dependent metabolic activation of N-hydroxy-3, 2'-dimethyl-4-aminobiphenyl and several carcinogenic N-hydroxy arylamines in relation to tissue and species differences, other acyl donors, and arylhydroxamic acid-dependent acyltransferases

Abstract: The metabolic activation of several carcinogenic N-hydroxy (N-OH)-arylamines by cytosolic S-acetyl coenzyme A (AcCoA)-dependent enzymes was examined in tissues and species susceptible to arylamine carcinogenesis. Comparisons of the AcCoA-dependent activity were also made with known cytosolic arylhydroxamic acid-dependent acyltransferases and with the ability of different acyl donors to mediate the binding of N-OH-arylamines to DNA. With rat hepatic cytosol, AcCoA-dependent DNA binding was demonstrated for several [3H]N-OH-arylamines, in the order: N-OH-3,2'-dimethyl-4-aminobiphenyl (N-OH-DMABP), N-OH-2-aminofluorene (N-OH-AF) greater than N-OH-4-aminobiphenyl greater than N-OH-N'-acetylbenzidine greater than N-OH-2-naphthylamine; N-OH-N-methyl-4-amino-azobenzene was not a substrate. No activity was detected in dog hepatic or bladder cytosol with any of the N-OH-arylamines tested. Using either N-OH-DMABP or N-OH-AF and rat hepatic cytosol, activation to DNA-bound products was also detected with acetoacetyl- and propionyl-CoA but not with folinic acid or six other acyl CoA's. However, p-nitrophenyl acetate which is known to generate acetyl-enzyme intermediates effectively replaced AcCoA. Subcellular fractionation of rat liver showed that the AcCoA-dependent DNA-binding of N-OH-DMABP with cytosol was 5 times greater than that obtained with the microsomal or mitochondrial/nuclear fractions. Furthermore, the cytosolic activity was insensitive to inhibition by the esterase/deacetylase inhibitor, paraoxon; while the activity of the other subcellular fractions was completely inhibited (greater than 95%). AcCoA-dependent activation of N-OH-DMABP was also detected with rat tissue cytosols from intestine, mammary gland and kidney, which like the liver, are targets for arylamine-induced tumorigenesis. Using N-OH-DMABP, AcCoA-dependent DNA-binding activity was also detected in the hepatic cytosols from several species in the order: rabbit greater than hamster greater than rat, human greater than guinea pig greater than mouse. In contrast, the arylhydroxamic acid, N-OH-N-acetyl-DMABP, was not activated to a DNA-binding metabolite by the hepatic cytosolic N,O-acyltransferase of any of these species, thus suggesting that the AcCoA-mediated binding of N-OH-DMABP results from the direct formation of N-acetoxy-DMABP. With N-OH-AF as the substrate, the AcCoA-dependent activation was in the order: rabbit greater than guinea pig, hamster greater than mouse greater than human, rat.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk Analysis with Single-Index Portfolio Models: An Application to Farm Planning

Abstract: Sharpe's 1963 single-index portfolio model, the separation theorem, and a solution method suggested by Elton, Gruber, and Padberg are adapted in this paper to the farm diversification problem. The objectives are to develop risk measures, based on single-index parameters and computationally simple methods for farm risk planning, that are suitable for microcomputers and modern hand-held calculators. The intent is to produce a normative model with possible extension applications.

Alterations in plasma-volume-corrected blood components of marathon runners and concomitant relationship to performance.

Abstract: The study was undertaken to determine the effects of running a marathon on concentration of various blood components resulting from phenomena other than fluid loss, and these were related to performance times. Twenty male marathon runners ranging from 20 to 50 years of age participated in the study. Blood samples were collected before and after the subjects ran in a marathon. Blood samples were analyzed for sodium, potassium, glucose, lactate dehydrogenase, creatinine, creatine phosphokinase, triglycerides, cholesterol, hematocrit, hemoglobin, protein, white blood cell number, uric acid, carbon dioxide, and iron. All of the blood parameters increased significantly in concentration with the exceptions of glucose and carbon dioxide which decreased. After accounting for plasma-volume loss (COR), there remained significant increases in blood serum lactate dehydrogenase, creatinine, creatine phosphokinase, uric acid, iron, and whole-blood white blood cell number. Significant decreases in COR serum sodium, protein, glucose, and carbon dioxide were found. Lactate dehydrogenase and creatine phosphokinase concentration changes support the concept of acute damage to muscle tissue resulting from marathon running. No strong relationship between performance time and other measured variables was found. COR measures were more representative of marathon induced blood changes from physiological dynamics other than plasma volume change than presently reported findings.

Effect of preprocessing treatments on the firmness and quality characteristics of whole and sliced strawberries after freezing and thermal processing

Abstract: Procedures designed to improve fruit firmness of overripe strawberry fruit originally designated for the fresh market were investigated. The firmness of ‘Cardinal’ strawberries was increased by soaking or vacuum infiltrating in 1 or 2% Ca lactate solutions. Calcium lactate was more effective in firming sliced than whole fruit. Thermally processed fruit benefited more from calcium absorption than did the frozen, thawed fruit. Whole fruit firmness was increased by the vacuum infiltration of Ca lactate. There was little increase in firmness of the sliced fruit when the calcium was vacuum infiltrated as compared to a soak treatment with no vacuum. There were slight but significant differences among treatments on all quality attributes tested. However, these quality differences would have no commercial importance.

Pulsed photothermal deflection spectroscopy in a flowing medium: a quantitative investigation.

Abstract: A comprehensive investigation of pulsed photothermal deflection spectroscopy in a flowing medium has been carried out. A rigorous solution of the appropriate diffusion equation has been obtained, and experiments have been conducted to verify the theoretical predictions. Absolute measurements of the photothermal deflection were made and no adjustable parameters were used in the theory. Very good agreement between the theory and the experiment was obtained.

Quantum fluctuations in absorptive bistability without adiabatic elimination.

Abstract: A linearized theory of fluctuations for absorptive bistability based on the positive P representation is developed without adiabatic elimination of the atoms or the field. An analytic expression for the steady-state covariance matrix is derived from which the size of quantum-statistical effects can be estimated without restriction to the good- or the bad-cavity limit. When the atom and field relaxation rates are similar the intensity correlation function of the transmitted light exhibits an oscillatory relaxation associated with vacuum Rabi splitting.

Oxidative microsomal metabolism of 1-nitropyrene and DNA-binding of oxidized metabolites following nitroreduction

Abstract: 1-Nitropyrene is an environmental mutagen and carcinogen which undergoes both oxidative and reductive metabolism. We have previously shown that nitroreduction to N-hydroxy-1-aminopyrene leads to the formation of arylamine--DNA adducts. In the present study, we have investigated the oxidative metabolism of 1-nitropyrene and the subsequent binding of ring-oxidized metabolites to DNA. In vitro incubations were conducted using hepatic microsomes from uninduced rats or from rats pretreated with phenobarbital, Aroclor 1254, 3-methylcholanthrene, or 3-methylcholanthrene and trans-stilbene oxide. H.p.l.c. analysis of the incubation mixtures indicated the presence of the previously reported metabolites, 1-aminopyrene, 3-, 6-, and 8-hydroxy-1-nitropyrene, and 1-nitropyrene trans-4,5-dihydrodiol. In addition, 1-nitropyrene 4,5-oxide, 1-nitropyrene 9,10-oxide, 1-nitropyrene trans-9,10-dihydrodiol and 1-pyrenol were identified. The formation of both K-region dihydrodiols could be increased by trans-stilbene oxide induction of microsomal epoxide hydrase. Formation of the K-region epoxides was greatest using phenobarbital- and Aroclor-induced microsomes and increased with increasing oxygen tension, while 1-pyrenol formation was highest in 3-methylcholanthrene-induced microsomal incubations and was not affected by the oxygen tension. When calf thymus DNA was added to the microsomal incubations, similar levels of DNA-binding occurred in incubations conducted under oxygen, air, argon or anaerobic conditions. H.p.l.c. analysis of the enzymatically hydrolyzed DNA indicated the presence of multiple DNA adducts with the major product coeluting with N-(deoxyguanosin-8-yl)-1-aminopyrene. The K-region oxides bound directly to DNA to give adducts similar to the minor products detected in the microsomal incubations. Incubation of the K-region oxides with the nitroreductase, xanthine oxidase, increased the DNA-binding and resulted in an additional adduct which coeluted with N-(deoxyguanosin-8-yl)-1-amino pyrene. 3-Hydroxy-1-nitropyrene bound extensively to DNA upon nitroreduction by rat liver cytosol or xanthine oxidase, while 6- and 8-hydroxy-1-nitropyrene bound only slightly. None of these oxidized metabolites was activated to DNA-binding species by cytosolic nitroreduction followed by AcCoA-dependent acetylation. The fact that oxidized metabolites of 1-nitropyrene are reduced to DNA-binding derivatives more easily than 1-nitropyrene itself may be important in vivo where 1-nitropyrene has been shown to be readily oxidized.

Multipliers of bergman spaces into lebesgue spaces

Abstract: Let U be the open unit disk in the complex plane endowed with normalized Lebesgue measure m. will denote the usual Lebesgue space with respect to m, with 0

Multiple Storage Quad Trees: A Simpler Faster Alternative to Bisector List Quad Trees

Abstract: A bisector list quad tree is a quad tree which stores objects intersecting more than one quad on horizontal and vertical bisector lists. This is the form of quad tree originally proposed by Kedem for organizing boxes and polygons in a plane so that one can quickly find the objects intersecting an arbitrary window. A multiple storage quad tree is a quad tree which stores pointers to objects intersecting more than one quad in all of the quads that they intersect. This paper describes and analyzes multiple storage quad trees. It is shown that multiple storage quad trees can be efficient in storage space, often using less than 25 percent more space than a simple list of the objects. That is, the tree nodes and other pointers combined often use less than 25 percent of the space needed to store the object descriptions. It is also shown that using multiple-storage quad trees makes possible very rapid searches for the objects intersecting a small window. In most cases fewer than 10 nodes must be examined per object found in the window. Finally, multiple storage quad trees and the algorithms which operate on them are found to be very simple and intuitive.

Ab initio studies of structural features not easily amenable to experiment: Part 49. Conformational analysis and molecular structures of ethylenediamine and aminoethanol

Abstract: The structures of eleven conformations of aminoethanol and of ten conformations of ethylenediamine were determined by ab initio gradient geometry optimization on the 4–21G level. The calculations show that many energetically different conformers exist for the gauche and trans forms (NCCO or NCCN torsions) of both systems. The results indicate that structural effects on NH bond distances associated with aliphatic N⋯N or NH⋯O type hydrogen bonding are less noticeable than those obtained previously for other XH⋯Y interactions. In the same way as CH and CC bonds in aliphatic compounds studied previously, NH bonds in the same NH2-group anti-periplanar to CH are found here to be slightly longer (∼0.001 A) than NH bonds antiperiplanar to CC. The most stable 4–21G conformations of ethylenediamine (NCCN ≅ 58° and 62°) are identical with the main conformer identified by others in the gas electron diffraction data of this compound (NCCN = 64° ± 4), but the calculations afford a more detailed description of the NH2 arrangements (NC torsions) than that obtained by the gas phase experimental data. Structural effects of electron lone-pair orientation are discussed. A small but potentially significant discrepancy exists between the electron diffraction rg average CC bond distance (1.545 A ± 0.008) and the calculated rg value (1.528 A ± 0.003; 4–21G average value empirically corrected as described previously). Experimental and calculated average rg CN bond distances are 1.469 A ± 0.004 and 1.463 A ± 0.006, respectively. Some aspects of the CC bond discrepancy are discussed in detail.

Optical measurement of the evaporation of sulfuric acid droplets.

Abstract: Single micron-size sulfuric acid droplets are levitated in vacuum in a quadrupole trap through which passes the beam from a He–Ne laser. Scattered light is monitored by a fixed detector as cavity resonances are excited in the evaporating droplet. Mie-Debye theory is used to determine particle size, which, with kinetic theory, yields vapor pressure. Over the temperature range studied, −10 to +30°C, the vapor pressure of pure sulfuric acid is lnp(Torr) = (20.70 ± 1.74) − (9360 ± 499)/T(K).

Synthesis and mutagenicity of 1-nitro-6-nitrosopyrene and 1-nitro-8-nitrosopyrene, potential intermediates in the metabolic activation of 1,6- and 1,8-dinitropyrene.

Abstract: 1,6-Dinitropyrene and 1,8-dinitropyrene are environmental contaminants which are mutagenic in bacteria and cultured mammalian cells. Since nitroreduction, and possibly O-acetylation, have been implicated in the metabolic activation of these compounds, the reduced intermediates, 1-nitro-6-nitrosopyrene and 1-nitro-8-nitrosopyrene, were synthesized and their mutagenicity examined in Salmonella typhimurium and Chinese hamster ovary (CHO) cells. Nitration of 1-acetylaminopyrene yielded a mixture of 1-acetylamino-6-nitropyrene and 1-acetylamino-8-nitropyrene, which was separated by flash chromatography. Following deacetylation, the amino-nitropyrenes were oxidized to the desired nitronitrosopyrenes with m-chloroperoxybenzoic acid. Both nitronitrosopyrenes showed similar levels of mutagenicity in S. typhimurium strain TA98 and a nitroreductase-deficient analogue, TA98NR, but much lower activity in the esterificase-deficient strain, TA98/1,8-DNP6, which suggested that reduced metabolites require further activation by O-acetylation. In contrast, the analogous compound, 1-nitrosopyrene, was equally mutagenic in all three strains while its parent compound, 1-nitropyrene, demonstrated a much reduced mutagenicity in strain TA98NR. In CHO cells, 1-nitropyrene was not mutagenic and the dinitropyrenes were only weakly active, while all three nitrosopyrene derivatives were highly mutagenic. These data support the hypothesis that nitrated pyrenes are metabolized to mutagens through nitroreduction. In Salmonella the limiting step in the metabolic activation of 1-nitropyrene appears to be the initial reduction to 1-nitrosopyrene, while with the dinitropyrenes subsequent esterification of the reduced intermediates seems critical. With CHO cells, the initial reduction to nitroso derivatives is the limiting step for all nitropyrenes, and esterification does not appear to occur in the activation sequence.

Simultaneous saccharification/fermentation with Zymomonas mobilis.

Abstract: In recent years, an ethanol production process has been developed which utilizes Trichoderma reesei cellulase and Candida brassicae IFO 1664 in the simultaneous saccharification/fermentation (SSF) of cellulose to ethanol. The direct production of ethanol from cellulose in an SSF process alleviates the problem of end production inhibition. Glucose does not accumulate in this system, but rather is fermented to ethanol immediately following saccharification. The result is an increase in yield of 25% or greater as compared with separate processes of saccharification and fermentation. An alternative organisms which might be used in place of yeasts in ethanol production processes is Zymomonas mobilis. The optimum temperature for hydrolysis of cellulose by Trichoderma reesei cellulases is 50/sup 0/C. Since this hydrolysis is the rate limiting step in the SSF process, it is advantageous to utilize the most temperature tolerant ethanol producer available. Candida brassicae is currently the organism of choice due to its ability to produce ethanol efficiently at 40/sup 0/C. This investigation reports on the screening of Zymomonas strains and evaluating the feasibility of utilizing the most temperature tolerant strain in place of C. brassicae in SSF.

Influence of Aging and Protein Deficiency on Neutrophil Function

Abstract: This study examined the effect of age and protein deficiency on the function of mouse neutrophils. Compared with appropriate controls aging and protein deficiency caused significant reductions in respiratory burst activity, exocytosis, and enzyme release from neutrophils. Individually, neither aging nor protein deficiency caused decreases in the ability of the neutrophil to phagocytose or kill bacteria. When aged animals were fed a protein deficient diet, however, further reductions in neutrophil function occurred that resulted in significant decreases in phagocytosis and bacterial cell kill. These findings indicate that both aging and protein deficiency compromise neutrophil function. When both variables are present the abnormalities become sufficient to affect the neutrophils' most critically important functions. The results emphasize the importance of protein deficiency in the aged and help explain the high prevalence of bacterial infection in malnourished older individuals.

Relationship Between Degree of Pectin Methylation and Tissue Firmness of Cucumber Pickles

Abstract: The relationship between pectin methylation and tissue firmness was examined in cucumber pickles exposed to pre-brining and brining treatments. Tissue treated with CaCl2 prior to or during brining, blanched before brining or held at 2°C during brine storage resisted softening. Although all treatments reduced the degree of esterification (DE) of pectic substances, less demethylation occurred in treatments that protected against softening. Join point regression analysis of the data indicated that maximum firmness of mesocarp tissue was attained when the DE of pectins was 12.3 ± 1.2 or greater. Firmness declined concomitantly when the DE declined below 12.3 ± 1.2. Methods that protect against excessive demethylation of pectins appear to be important in retarding softening of cucumber pickle tissue during storage in brine.

Aerosol particle charge and size analyzer

Abstract: An instrument for analyzing the size and charge of aerosol particles employs a dual beam laser Doppler velocimeter to track the motion of a particle while subjecting the particle to a sinusoidal acoustic field and to a pulsed, high voltage electric field. The particle transmitting through the crossed beams of the laser Doppler velocimeter moves with an oscillatory motion due to the acoustic field and, if the particle is charged, it has a horizontal drift parallel to the electric field during the electric pulse. The phase lag of the particle's motion with respect to the acoustic field is measured to determine the aerodynamic diameter of the particle and the velocity and the direction of the drift relative to the polarity of the applied high voltage electric field is used to determine the magnitude and polarity of the electric charge of the particle.

Determination of thorium, uranium and plutonium isotopes in atmospheric samples

Abstract: A new procedure for the radiochemical measurements of thorium, uranium and plutonium in atmospheric samples is described. Analysis involves coprecipitation of these actinides with iron hydroxide from a 40-to 50-dm3 sample of rainwater, followed by radiochemical separation and purification procedures by the use of ion exchange chromatography (Dowex AG1×8) and solvent extraction. The new procedure enables one to determine the isotopes of thorium, uranium and plutonium, which are found in rainwater at extremely low concentrations, with a chemical yield ranging from 60 to 80%.

Quasilinear multistep methods and variable step predictor-corrector methods for neutral functional differential equations

Abstract: The theory of quasilinear multistep methods and predictor–corrector methods for neutral functional differential equations is developed. The theorem about the asymptotic behaviour of the global discretization error of quasilinear methods, which forms a theoretical basis for step control strategy for predictor–corrector methods for neutral equations, is given. Some problems of implementation of these methods are also addressed, and the results of numerical experiments are presented.