Showing papers by "Louisiana State University published in 1973"
TL;DR: In this paper, the ground state energy of a system of interacting electrons is expressed as a functional function of the current density of the system, and a spin-dependent term which leads, in the nonrelativistic limit, to a local potential which is also spin dependent.
Abstract: This work is a generalization of the Hohenberg---Kohn---Sham theory of the inhomogeneous electron gas, with emphasis on spin effects. An argument based on quantum electrodynamics is used to express the ground-state energy of a system of interacting electrons as a functional of the current density. Expressions are derived for coefficients appearing in an expansion of the correlation functional in terms of the linear-response functions of the homogeneous system, for a gas of almost constant four-current density. The current density contains a spin-dependent term which leads, in the nonrelativistic limit, to a local potential which is also spin dependent. This potential is applied to the problems of spin splitting of energy bands in ferromagnets and spin-density-wave antiferromagnets. The relations between the present approach, that of Slater, and the collective electron theory of ferromagnetism of Stoner are described.
574 citations
TL;DR: The enzyme electrode determination of blood sugar compares favorably with commonly used methods with respect to accuracy, precision, and stability.
498 citations
Book•
26 Mar 1973493 citations
Book•
01 Jan 1973311 citations
TL;DR: The log of the number of TMV particles attached to grids serologically specific for TMV decreased linearly with dilution of virus extract, and the method simplified the collection and analysis of virus particles.
237 citations
TL;DR: It is shown that dichotically presented nonsense syllables with strict acoustic and phonetic control of the stimuli, generate a right ear advantage that is essentially fixed by 5 years of age.
189 citations
TL;DR: In this paper, it was shown that the electric and magnetic response should approach the same ($q √ √ q √ n σ √ σ σ n √ N √ 1/σ 1/n σ 2 ) asymptotic limit in the limit of zero interparticle separation.
Abstract: The behavior of interacting electrons is dominated by the Coulomb repulsion in the limit of zero interparticle separation. Hence, in this limit the derivative of the two-particle correlation function is equal to the two-particle correlation function itself divided by the Bohr radius. Because correlation functions can be obtained from linear-response functions, the relation between the correlation function and its derivative can be used as a criterion for the validity of approximate linear-response functions. Some of the more familiar dielectric functions and spin susceptibilities are discussed in this context. For these response functions it is shown that the electric and magnetic response should approach the same ($q\ensuremath{\rightarrow}\ensuremath{\infty}$) asymptotic limit.
181 citations
TL;DR: The glucose electrode constructed and the use of flow-stream experiments with two iodide sensors provided accurate and convenient glucose determinations in the absence of some oxidizing and reducing agents.
123 citations
TL;DR: In this paper, the authors describe phytokarst as a distinctive landform resulting from a curious type of biologic erosion, where filamentous algae bore their way into limestone to produce black-coated, jagged pinnacles marked by delicate, lacy dissection.
Abstract: Phytokarst is a distinctive landform resulting from a curious type of biologic erosion. Filamentous algae bore their way into limestone to produce black-coated, jagged pinnacles marked by delicate, lacy dissection that lacks any gravitational orientation. Ordinary rainfall-produced karst and littoral karst are characterized by flat-bottomed pans and vertically oriented flutes, thus differing from phytokarst. Algae attack by dissolving calcite preferentially to dolomite.
115 citations
TL;DR: Strengite (FePO4 � 2H2O) undergoes partial dissolution under the reducing conditions existing in a flooded soil, resulting in the greatest release of phosphate and iron.
Abstract: Strengite (FePO(4) . 2H(2)O) undergoes partial dissolution under the reducing conditions existing in a flooded soil. The greatest release of phosphate and iron occurs under conditions of low oxidation-reduction potential in combination with low pH.
105 citations
Journal Article•
TL;DR: These 5′-terminal sequences are complementary and rotationally symmetrical, showing how the enzyme may produce DNA fragments with short cohesive ends.
Abstract: Restriction endonuclease EcoRII makes about twenty double-stranded breaks per molecule of λh80 DNA. The 5′-terminal sequences are pC-C-A-G-G and pC-C-T-G-G. These are complementary and rotationally symmetrical, showing how the enzyme may produce DNA fragments with short cohesive ends.
TL;DR: The active delta of the Mississippi River was sampled in August 1968 to determine plant species composition, plant coverage, and soil and water chemistry as discussed by the authors, and 2 weeks after the hurricane, the delta was resampled 2 weeks following the hurricane to evaluate the immediate effects on vegetation, soil, and water, and again 1 year after a hurricane to determine the recovery rate of vegetation.
Abstract: The active delta of the Mississippi River was sampled in August 1968 to determine plant species composition, plant coverage, and soil and water chemistry. Hurricane Camille struck this area in August 1969, with winds in excess of 200 km/h and tides raging upward to 5.2 m above MSL. The delta was resampled 2 weeks following the hurricane to evaluate the immediate effects on vegetation, soil, and water, and again 1 year after the hurricane to determine the recovery rate of vegetation. The hurricane resulted in a drastic reduction of vegetation. Regrowth was rapid in the delta marshes and after 1 year plant coverage approached pre—hurricane levels of abudance; however, recovery was slower in ponds and lakes. The loss of vegetation was mainly a result of the sweeping action of wind and water, and plants were either uprooted or ripped apart and carried away by the current. Water salinity increased with the hurricane but declined by the following year and appeared to have only slight effect on marsh vegetation. Plant species caried in their response to the hurricane. Bacopa monnieri showed practically no effect, and Phragmites communis and Spartina alterniflora were reduced only slightly. Myriophyllum spicatum, Panicum repens, and Alternanthera philoxeroides were greatly reduced by the storm: and after 1 year, only Alternanthera philoxeroides showed significant recovery.
TL;DR: P-Nitrophenyl-p'-guanidinobenzoate is a suitable substrate for the titration of purified bovine Factor X which has been activated by a coagulant protein from Russell's viper venom reaction.
TL;DR: The results demonstrate that patients could be conditioned to lower blood pressure by 20% to 30% over a period as brief as four days by providing an external signal and verbal praise contingent upon each reduction in diastolic pressure that met a pre-set criterion.
Abstract: Eighteen male essential hypertensive patients participated in an experiment designed to compare two strategies for controlling high blood pressure. Each strategy was derived from the instrumental learning literature, and the aim was to treat the blood pressure response as an operant and determine the most effective conditioning procedure for manipulating it. The results demonstrate that patients could be conditioned to lower blood pressure by 20% to 30% over a period as brief as four days by providing an external signal and verbal praise contingent upon each reduction in diastolic pressure that met a pre-set criterion.
TL;DR: Streptococcus mutans, S sanguis, and S salivarius use a PEP-dependent phosphotransferase system that results in phosphorylation of glucose at carbon 6, which is not sensitive to fluoride.
Abstract: Streptococcus mutans, S sanguis, and S salivarius use a phosphoenolpyruvate (PEP)-dependent phosphotransferase system that results in phosphorylation of glucose at carbon 6. This enzyme system is not sensitive to fluoride. Glucose uptake into resting cell suspensions is sensitive to fluoride because of inhibition of intracellular PEP production. The glucose phosphotransferase system is constitutive in oral streptococci.
TL;DR: In this article, the properties of two dilatational motions in the context of generalized thermoelasticity are studied and the exact solution to the frequency equation is given and exact values of the real and imaginary parts of the wave number are calculated.
TL;DR: Investigation was made to determine whether high blood pressure (hypertension) could be lowered thru muscular relaxation and hypnosis, and significant lowering of both systolic and diastolic pressures was obtained.
Abstract: Investigation was made to determine whether high blood pressure (hypertension) could be lowered thru (a) muscular relaxation and (b) hypnosis. Six non-medicated hypertensive patients were used as controls while another six served as treatment Ss receiving muscular relaxation and hypnosis procedures. Nine patients on stabilized anti-hypertensive medication also received the muscular relaxation and hypnosis procedures. Significant lowering of both systolic and diastolic pressures was obtained in both the no drug and drug groups receiving treatment, but there was no significant reduction in the control group. Hypertensive levels were reduced thru muscular relaxation and completely eliminated during hypnosis. Instruction was given in self-relaxation and self-hypnosis to promote continuation of beneficial effects beyond hospitalization.
TL;DR: Daily variations in concentrations of plasma corticosterone were found in pigeons maintained on 12-hr and 16-hr daily photoperiods, with rapid increases occurred within a few hours after the onset of the dark period and a gradual reduction during the light.
TL;DR: In this article, it was shown that the space of absolutely summing operators from E to F is reflexive if both E and F are reflexive and E has the approximation property.
TL;DR: The signal assignments made on the basis of 13C chemical shifts and 13C-31P spin-spin couplings indicate that the earlier assignments of the C-4 and C-5 resonances of α- and β-fructofuranose in oligosaccharides and D-fructose should be reversed.
TL;DR: Of 3459 specimens of Triatoma dimidiata found in and around 198 houses in an endemic Chagas' disease area in Costa Rica, most of those captured indoors were concentrated near the beds, and human blood was the most common in the gut content of the bugs.
Abstract: Of 3459 specimens of Triatoma dimidiata found in and around 198 houses in an endemic Chagas' disease area in Costa Rica, most of those captured indoors were concentrated near the beds. In the periphery of the houses these insects were more common in stacks of firewood; they were also found in firewood being carried inside. Within a radius of 1000 m from the nearest house, T. dimidiata was also found in hollow trees, mainly those inhabited by opossums.
Precipitin tests revealed that human blood was the most common in the gut content of the bugs (63.7% for those captured indoors and 21.9% for those outdoors), followed in descending order by blood from dog, rat (or mouse), chicken, and opossum. This does not indicate a preference for man but rather that he is the most available host. Mobility of T. dimidiata is indicated by the fact that human blood was found in those captured outside which presumably came from indoor populations. Blood from other hosts including cold-blooded animals, either alone or in combination, was also identified in some T. dimidiata . One bug contained blood from 6 different hosts. Rat and opossum bloods were more common in T. cruzi-positive insects whereas blood of chicken and toad were more frequent in the negative groups. The concurrent finding of human and or domestic animal and opossum blood in some T. dimidiata , plus the natural association of the marsupial and T. dimidiata in Costa Rica, is strong evidence of a link between the wild and the domestic cycles of T. cruzi .
TL;DR: In this article, a noniterative integral-equation theory is used to solve the coupled integrodifferential equations of the scattering problem from zero out to some transformation point where the reactance matrix is projected out to its asymptotic value by using a matrizant technique.
Abstract: A procedure which allows for both open and closed channels with exchange and orthogonality is formulated for a multichannel scattering process. Noniterative integral-equation theory is used to solve the coupled integrodifferential equations of the scattering problem from zero out to some transformation point where the reactance matrix is projected out to its asymptotic value by using a matrizant technique. The method is applied to a two-channel model which has some of the features of a $1s\ensuremath{-}2p$ approximation for $e$-H scattering.
TL;DR: A technique for benzyl derivatization of fatty acids which results in enhanced ultraviolet absorption with a concomittant increase in sensitivity in liquid chromatographic (LC) separations has been developed.
Abstract: A technique for benzyl derivatization of fatty acids which results in enhanced ultraviolet absorption with a concomittant increase in sensitivity in liquid chromatographic (LC) separations has been developed. Benzylation prior to liquid chromatographic separation also provides a uniform enhancement of response for fatty acids which permits direct relative quantization without acquisition of additional calibration data. After removal of excess solvent from eluted compounds mass spectra were determined using a direct probe which confirmed the benzyl ester structures. A discussion of spectral data and the advantages of using mass spectrometry as an ancillary tool to liquid chromatography is also discussed.
TL;DR: In this paper, it was shown that the difference in potential between the first ring oxidation and first ring reduction is constant and has a value of 2.25 f 0.1 5 volts.
Abstract: Several metalloporphyrins are well known participants in various types of biologically important electron exchange reactions. These include iron porphyrins which are components of cytochromes, catalase and peroxidase; a cobalt porphyrinlike derivative which is an essential component of vitamin BIZ; and chlorophyll, a dihydroporphyrin, containing magnesium. In order to better understand these biological electron transfer processes, studies which elucidate the mechanisms and factors governing the rate of metalloporphyrin redox reactions are important. h hemoglobin the rate at which the iron (11) porphyrin moiety is oxidized is extremely slow' in contrast to the rapid oxidation of simple ferroheme. The difference in redox potentials is not nearly enough to account for the difference in rate. It has been suggested that the slowness of oxidation is due to such factors as the hydrophobic media which surround the iron porphyrin in or to the large change in spin quantum number associated with the oxidation of hemoglobin by ~ x y g e n . ~ On the other hand, the rate of oxidation of cytochrome c is very rapid.4 The application of electrochemical techniques to the study of the rates of electron transfer involving metalloporphyrins holds promise for elucidating the factors which govern the rate of electron transfer involving metalloporphyrins in biological systems. During the past few years a number of studies have appeared which applied electrochemical techniques to the investigation of metallop~rphyrins.~-~ It was found that in nonaqueous solvents it is possible to oxidize the ring of a typical metalloporphyrin in two discrete oneelectron steps yielding srcation radicals and dications and to also reduce the ring by two electrons yielding sr-anion radicals and d i a n i ~ n s . ~ ~ Ordinarily, if the central metal ion can change oxidation state (i.e., Fe(II)+ Fe(III)), this occurs between the first ring oxidation and the first ring reduction. The question of whether the electron transfer involves the porphyrin ring or the metal can be settled by ESR spectra or magnetic meas~remen t s . ' ~~*~ Also, the rates of axial ligand exchangelo and the rates of electron transfer in certain cases have been determined.12*14 Recently, using the technique of cyclic voltammetry, we have measured the rates and examined the mechanisms of electron transfer of a large number of metalloporphyrins in nonaqueous solvents such as butyronitrile and dimethylsulfoxide.' s Examination of thermodynamic half-wave potentials (Et) indicates that the difference in potential between the first ring oxidation and first ring reduction is constant and has a value of 2.25 f 0.1 5 volts. Furthermore, the Et's of the ring oxidation and the ring reduction can be correlated with the net ring charge as calculated by Gouterman.16s17 In addition a constant difference between the first ring oxidation and the second (0.30 f 0.05 volts), as well as the first ring reduction and the second (0.42 f 0.05 volts), was consistent with such reports in the literature for similar
TL;DR: Rhesus monkeys, maternally seprated at birth, were individually housed with a simple artificial mother in cages that were either completely enclosed (Enclosed Group) or had a clear plastic fron that faced the general nursery environment (Visual Group), reflected in longitudinal and diurnal contrasts between groups.
Abstract: Rhesus monkeys, maternally seprated at birth, were individually housed with a simple artificial mother in cages that were either completely enclosed (Enclosed Group) or had a clear plastic fron that faced the general nursery environment (Visual Group). Animals were removed from the living cage and placed for 1 hr in an enclosed carrying cage, either alone or with the artificial mother, following which blood samples were taken and analyzed for plasma cortisol levels. This procedure was repeated at monthly intervals during the first 7 months of life and at 9 and 12 months. In both groups plasma cortisol levels were higher when the animlas were alone than when the social surrogate was present. Rearing conditions were also effective, as reflected in longitudinal and diurnal contrasts between groups: cortisol levels were consistently high in the Visual Group from the 1st week of life, whereas the developmental pattern was curvilinear for the Enclosed Group. Significant diurnal variation in cortisol level was demonstrated only in the Visual Group.
TL;DR: In this article, a self-consistent tight-binding calculation of paramagnetic chromium was performed using Gaussian-type orbitals (GTO) and five individual GTO's for each state.
Abstract: The results of a self-consistent tight-binding calculation of the band structure of paramagnetic chromium are reported. The basis set consisted of atomic wave functions for the $1s$, $2s$, $3s$, $4s$, $2p$, $3p$, and $4p$ states expressed as linear combinations of Gaussian-type orbitals (GTO) and five individual GTO's for each $3d$ state. The exchange potential was calculated according to the $X\ensuremath{\alpha}$ method with $\ensuremath{\alpha}=\frac{2}{3}$. The initial Coulomb potential was constructed from the superposed charge densities of neutral chromium atoms in a $3{d}^{5}4{s}^{1}$ configuration. Eleven iterations were required to determine a self-consistent potential. The charge density was sampled at 55 inequivalent points in 1/48 of the Brillouin zone. Energy bands were calculated with the use of the self-consistent potential at 819 points in 1/48 of the zone. The density of states was calculated according to the Gilat-Raubenheimer method. Cross sections of the Fermi surface were obtained in several symmetry planes. The x-ray from factor was determined from the self-consistent wave functions.
TL;DR: In this article, the Compton profiles of the electron momentum distribution in chromium, iron, and nickel are calculated using the wave functions obtained from selfconsistent linear-combination of atomic-orbitals energy-band calculations.
Abstract: The Compton profiles of the electron momentum distribution in chromium, iron, and nickel are calculated using the wave functions obtained from self-consistent linear-combination-of-atomic-orbitals energy-band calculations. The results are compared with experiment.
TL;DR: An improved urea enzyme electrode applied for the determination of urea in blood samples showed good agreement with a standard spectrophotometric method, and routine clinical assays of blood urea are feasible.