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Showing papers by "University of Illinois at Chicago published in 1973"


Journal ArticleDOI
TL;DR: These findings provide a basis for reentrance in some patients with reentrant PSVT, as manifest by dual A-V nodal conduction times and refractory periods, and Antegrade failure of the fast pathway with subsequent availability for retrograde conduction could allow A- V nodal reentry.
Abstract: Electrophysiological evidence suggestive of dual atrioventricular (A-V) nodal pathways is presented in two patients with normal P-R interval and reentrant paroxysmal supraventricular tachycardia (PSVT). His bundle recordings and atrial stimulation were used to obtain this electrophysiological evidence. Refractory periods were measured with the atrial extra-stimulus technique. Plotting of H1-H2 responses against A1-A2 coupling intervals revealed that as A1-A2 decreased, H1-H2 decreased appropriately. At a critical A1-A2, a sudden marked increase in H1-H2 occurred, suggesting failure of fast pathway, (defining the fast pathway effective refractory period ERP). Further shortening of A1-A2 defined a second H1-H2 curve. The longest A1-A2 with no H2 response was defined as the slow pathway ERP. Echo zones coincided with A1-A2 intervals equal to or less than the fast pathway ERP. These results provide the first electrophysiological demonstration of dual A-V nodal pathways in patients with normal P-R interval and...

524 citations


Journal ArticleDOI
TL;DR: The nerve trunks of the lumbar plexus, which run into the inferior extremity, are at a great distance from each other, so much so that in order to produce anesthesia it is difficult to obtain complete anesthesia, and there is frequent failure of the blocks.
Abstract: HEN regional anesthesia was still in W its infancy, one of the pioneers in the field, George Hirschel, who in 1911 had described the first axillary approach to the brachial plexus, made the following statement: “Local anaesthesia for operations on the lower limb has not kept pace with the advances of that of the upper limb. The anaesthetization of the lumbar plexus in a manner analogous to that of the brachial has not so far been successful.”l Over the next half century these words have been echoed by many of the great regional anesthetists of the past,2-6 because, as Dogliotti so aptly pointed out, “The nerve trunks of the lumbar plexus, which run into the inferior extremity, are at a great distance from each other, so much so that in order to produce anesthesia. multide mocedures are it is difficult to obtain complete anesthesia, and there is frequent failure of the blocks.”fi

481 citations



Journal ArticleDOI
TL;DR: In this paper, an iterative technique is proposed for the absolute deviations regression of data, which is based on any standard least squares curve fitting algorithm, and the resulting regression procedure is computationally simple, requires less storage and is faster than the linear programming algorithm.
Abstract: An iterative technique is proposed for the absolute deviations regression of data. At the heart of the technique is any standard least squares curve fitting algorithm. Hence, the resulting regression procedure is computationally simple, requires less storage and is faster than the linear programming algorithm recently proposed as a solution to this problem. Problems associated with non-unique solutions in least absolute deviations regression are also discussed.

220 citations



Journal ArticleDOI
TL;DR: By integrating the number of licks that occur during these brief exposure periods functions can be obtained that bear a striking similarity to palatability functions obtained by other methods, and provide evidence for a delayed post ingestive inhibitory effect on drinking rate that derives from a previously ingested meal.

192 citations


Journal ArticleDOI
01 Dec 1973-Synthese
TL;DR: In this paper, the authors define the notion of belief as degree of confidence, which can be ordered as to strength and admits of quantatization, and discuss the justification of condition (ii) from the point of view of a frequency interpretation of probability or reasonable degree of belief.
Abstract: I take bayesianism to be the doctrine which maintains that (i) a set of reasonable beliefs can be represented by a probability function defined over sentences or propositions, and that (ii) reasonable changes of belief can be represented by a process called conditionalization. Bayesians have produced several ingenious arguments in support of (i); but the equally important second condition they often seem to take completely for granted. My main aim is to fill this gap in those bayesian positions which characterize reasonable belief directly as a probability function. Thus, what follows applies equally to the bayesian personalists' views which characterize reasonable belief as having subjective sources and to views such as that of Carnap which attempt to explicitly define a function which characterizes the degree of belief it would be objectively reasonable for an idealized rational agent to have in a given proposition in stated circumstances. Many frequentist views are also classifiable as bayesian, and I will briefly discuss the justification of condition (ii) from the point of view of a frequency interpretation of probability or reasonable degree of belief. Along the way I will also have occasion to touch on the connection between conditionalization and observation. Throughout the discussion I will rely on several common bayesian presuppositions. The object of study is a notion of belief, perhaps most aptly described as degree of confidence, which can be ordered as to strength and admits of quantatization. Such beliefs, or degrees of confidence, are assumed to reveal themselves in an agent's disposition to make bets voluntarily or under duress. The agent whose beliefs are under discussion is assumed to be an ideal logician, and the set of propositions about which the agent has beliefs is assumed to be closed under all logical operations. Also, the set of propositions for which the agent entertains beliefs is assumed to be fixed. Quite clearly, when this assumption is violated, the bayesian model does not apply; and the most cogent arguments against

187 citations


Journal ArticleDOI
TL;DR: It is noted that the effects of depolymerizing microtubules in vivo might be easily quantitated in whole populations since no external wall or pellicle contributes to the maintenance or the biogenesis of the characteristic cell form of Ochromonas.
Abstract: In the first of two companion papers which attempt to correlate microtubules and their nucleating sites with developmental and cell division patterns in the unicellular flagellate, Ochromonas, the distribution of cytoplasmic and mitotic microtubules and various kinetosome-related fibers are detailed. Of the five kinetosome-related fibers, which have been found in Ochromonas, two, the kineto-beak fibers and the rhizoplast fibers are utilized as attachment sites for distinct groups of microtubules. The set of microtubules attached to the kineto-beak fibers apparently shape the anterior beak region of the cell whereas the rhizoplast microtubules appear to extend into and shape the tail in vegetative cells. In mitotic cells a rhizoplast is found at each spindle pole apparently serving as foci for the spindle microtubules. These findings are discussed in relation to the less well defined attachment sites for vegetative and mitotic microtubules in other kinds of cells. It is noted that the effects of depolymerizing microtubules in vivo might be easily quantitated in whole populations since no external wall or pellicle contributes to the maintenance or the biogenesis of the characteristic cell form of Ochromonas.

152 citations


Journal ArticleDOI
TL;DR: The paper modifies Ford and Fulkerson's maximal dynamic flow algorithm to construct a maximal dynamic network flow with a latest departure schedule and an earliest arrival schedule.
Abstract: This paper proves two properties of maximal network flows: 1 If there exist a maximal network flow with a given departure pattern at the sources and a maximal flow with a given arrival pattern at the sinks, then there exists a flow that has both this departure pattern at the sources and this arrival pattern at the sinks. 2 There exists a maximal dynamic network flow that simultaneously has a latest earliest departure schedule at the sources and an earliest latest arrival schedule at the sinks. The paper modifies Ford and Fulkerson's maximal dynamic flow algorithm to construct a maximal dynamic network flow with a latest departure schedule and an earliest arrival schedule.

148 citations


Journal ArticleDOI
01 Jul 1973-Chest
TL;DR: His bundle electrograms (H) were recorded in 61 patients without evidence of conduction disease on the surface electrocardiogram, in order to establish the normal range ofConduction intervals, which will be of use in assessing patients with suspected cardiac conduction Disease.

147 citations


Journal ArticleDOI
TL;DR: The results suggest close linkage of VH and CH genes and the cross-reactive idiotype was found in nearly all F1 mice tested, suggesting that idiotype must be a function of V region sequences.
Abstract: Anti-p-azophenylarsonate (anti-Ar) antibodies elicited in all strain A/J mice tested share one or more idiotypic specificities. These specificities are also found in the anti-Ar antibodies of mice of the closely related strain, AL/N, but not in those of BALB/c mice. Anti-Ar antibodies were elicited in congenic mice in which the IgCH locus of AL/N mice, which controls allotypic markers in the constant regions of heavy chains, had been introgressively backcrossed for nine generations onto a BALB/c background; the mice were then rendered homozygous for the AL/N allotypic determinant. On the average, these antibodies were quantitatively equivalent, with respect to content of the cross-reactive idiotype, to those of AL/N mice. This indicates that the gene controlling the idiotype is closely linked to the IgCH locus. Since idiotype must be a function of V region sequences, the results suggest close linkage of VH and CH genes. The cross-reactive idiotype was found in nearly all F1 mice (C57/BL x A/J or BALB/c x A/J) tested.

Journal ArticleDOI
TL;DR: It is suggested that the beak and rhizoplast sites could exert control over the position and timing of the appearance, the orientation, and the pattern of microtubule distribution in Ochromonas.
Abstract: The proposal made in the preceding paper that the species-specific shape of Ochromonas is mediated by cytoplasmic microtubules which are related to two nucleating sites has been experimentally verified. Exposure of cells to colchicine or hydrostatic pressure causes microtubule disassembly and a correlative loss of cell shape in a posterior to anterior direction. Upon removal of colchicine or release of pressure, cell shape regenerates and microtubules reappear, first in association with the kineto-beak site concomitant with regeneration of the anterior asymmetry, and later at the rhizoplast site concomitant with formation of the posterior tail. It is concluded that two separate sets of cytoplasmic tubules function in formation and maintenance of specific portions of the total cell shape. On the basis of the following observations, we further suggest that the beak and rhizoplast sites could exert control over the position and timing of the appearance, the orientation, and the pattern of microtubule distribution in Ochromonas. (a) the two sites are accurately positioned in the cell relative to other cell organelles; (b) in regenerating cells microtubules reform first at these sites and appear to elongate to the cell posterior; (c) microtubules initially reappear in the orientation characteristic of the fully differentiated cell; (d) the two sets of tubules are polymerized at different times, in the same sequence, during reassembly or resynthesis of the microtubular system. Experiments using cycloheximide, after a treatment with colchicine, have demonstrated that Ochromonas cannot reassume its normal shape without new protein synthesis. This suggests that microtubule protein once exposed to colchicine cannot be reassembled into microtubules. Pressure-treated cells, on the other hand, reassemble tubules and regenerate the normal shape in the presence or absence of cycloheximide. The use of these two agents in analyzing nucleating site function and the independent processes of synthesis and assembly of microtubules is discussed.

Journal ArticleDOI
TL;DR: It was concluded that the interaction of magnesium or calcium with P. aeruginosa, which results in its resistance to aminoglycoside antibiotics, is at a locus exterior to the bacterial membrane, probably in the cell wall or a linkage between thecell wall and membrane.
Abstract: Four aminoglycoside antibiotics were tested against five species of gram-negative bacilli in defined media with various concentrations of calcium and magnesium. A species-specific antagonism of antimicrobial action against Pseudomonas aeruginosa was observed. Antibiotics were not inactivated, but the bacilli became unsusceptible. Even after a long incubation in a bactericidal concentration of gentamicin, the addition of calcium stabilized P. aeruginosa and permitted bacterial replication in the presence of an otherwise lethal concentration of drug. Calcium and magnesium exerted their inhibitory effect only if the bacterial cell wall was intact. Also, the action of gentamicin on carbenicillin-induced spheroplasts of P. aeruginosa was not antagonized by calcium. It was concluded that the interaction of magnesium or calcium with P. aeruginosa, which results in its resistance to aminoglycoside antibiotics, is at a locus exterior to the bacterial membrane, probably in the cell wall or a linkage between the cell wall and membrane. Of five common species of gram-negative bacilli tested, the effect is speciesspecific for P. aeruginosa and is similar for all of the aminoglycoside antibiotics.

Journal ArticleDOI
TL;DR: In this paper, the lattice contribution of the octahedra is taken into account by using lattice of the isostructural [{C}{\mathrm{H}}_{3})}_{3}$NH]Co.
Abstract: The crystal structure at room temperature and the heat-capacity and magnetic susceptibilities at low temperatures of single crystals of [${(\mathrm{C}{\mathrm{H}}_{3})}_{3}$NH]Co${\mathrm{Cl}}_{3}$ \ifmmode\cdot\else\textperiodcentered\fi{} 2${\mathrm{H}}_{2}$O are reported. The orthorhombic crystals belong to the space group $\mathrm{Pnma}$ with $a=16.671(3)$ \AA{}, $b=7.273(1)$ \AA{} $c=8.113(2)$ \AA{}, and $Z=4$. The structure consists of chains of edge-sharing trans- [Co${\mathrm{Cl}}_{4}$${(\mathrm{O}{\mathrm{H}}_{2})}_{2}$] octahedra running parallel to the $b$ axis. At 4.135 \ifmmode^\circ\else\textdegree\fi{}K, [${(\mathrm{C}{\mathrm{H}}_{3})}_{3}$NH]Co${\mathrm{Cl}}_{3}$ \ifmmode\cdot\else\textperiodcentered\fi{} 2${\mathrm{H}}_{2}$O undergoes a second-order phase transition. The heat-capacity data have been analyzed using Onsager's solution for the two-dimensional Ising model. The lattice contribution was taken into account by using the lattice of the isostructural [${(\mathrm{C}{\mathrm{H}}_{3})}_{3}$NH]Cu${\mathrm{Cl}}_{3}$ \ifmmode\cdot\else\textperiodcentered\fi{} 2${\mathrm{H}}_{2}$O and a corresponding states procedure. The three principal-axis single-crystal susceptibilities display an unusual amount of anisotropy. Two of the data sets (one parallel and one perpendicular to the chemical chain) have been fit to an Ising linear-chain model. A small molecular-field correction significantly improved one of those fits. The $a$-axis susceptibility displays an unusually sharp rise, with decreasing temperature, very close to ${T}_{N}$ along with the suggestion of a net moment persisting below the transition. Thus, a Dzyaloshinsky-Moriya antisymmetric exchange interaction was assumed to be operative, since it is symmetry alowed in this space group, and Moriya's molecular-field-susceptibility calculation was used to fit this data set. All four of the data sets are quite reasonably described, the specific heat and one of the susceptibility sets within experimental error, by the following set of parameters: rectangular lattice exchange parameters of $\frac{J}{k}=(7.7\ifmmode\pm\else\textpm\fi{}0.2)$ \ifmmode^\circ\else\textdegree\fi{}K and $\frac{{J}^{\ensuremath{'}}}{k}=(0.09\ifmmode\pm\else\textpm\fi{}0.01)$ \ifmmode^\circ\else\textdegree\fi{}K; spectroscopic splitting parameters of ${g}_{a}=2.95\ifmmode\pm\else\textpm\fi{}0.05$, ${g}_{b}=3.90\ifmmode\pm\else\textpm\fi{}0.01$, and ${g}_{c}=6.54\ifmmode\pm\else\textpm\fi{}0.01$; and a Dzyaloshinsky-Moriya antisymmetric exchange parameter of $|\frac{D}{k}|=(4.9\ifmmode\pm\else\textpm\fi{}0.2)$ \ifmmode^\circ\else\textdegree\fi{}K. Finally, a consistent spin structure is proposed in which the intrachain interaction is ferromagnetic with the compound ordering antiferromagnetically below 4.135\ifmmode^\circ\else\textdegree\fi{}K such that there is a small net moment in the $a$ direction.

Journal ArticleDOI
01 Sep 1973-Nature
TL;DR: Ratings of students reveal an unfavourable image of physics and possible directions for improvement as discussed by the authors, and they suggest that physics can be improved in terms of physics education and research.
Abstract: Ratings of students reveal an unfavourable image of physics and possible directions for improvement.

Journal ArticleDOI
TL;DR: In this article, a group G is said to have a (B, N)-pair if there exist subgroups B and N of G satisfying the conditions: (1) G =
Abstract: Publisher Summary A group G is said to have a (B, N)-pair if there exist subgroups B and N of G satisfying the conditions: (1) G =


Journal ArticleDOI
TL;DR: The results show that p-HEMA membranes have a high permeability to urea due to a strong interaction between the polymer and urea, and they are consistent with a pore flow model in which solute transport takes place through water-filled regions essentially unaffected by the surrounding polymer matrix.
Abstract: The transport of urea and other biologically interesting solutes in aqueous solution across poly(2-hydroxyethyl methacrylate) (p-HEMA) hydrogel membranes has been studied. The results show that p-HEMA membranes have a high permeability to urea due to a strong interaction between the polymer and urea, and, in addition, they are consistent with a pore flow model in which solute transport takes place through water-filled regions essentially unaffected by the surrounding polymer matrix. The results indicate that such p-HEMA membranes might be suitable for hemodialysis applications.

Journal ArticleDOI
TL;DR: A mathematical model is developed for three-dimensional force analysis of the human vertebral column which accounts for nonlinearities due to large displacements and preliminary results are presented for the behavior of an isolated, ligamentous column under traction, lateral loads, and compressive loads which result in buckling.

Journal ArticleDOI
TL;DR: In vitro observations strongly suggest that PTH release is influenced by cyclic AMP in the parathyroid cell, and further suggest that the known hypocalcemic stimulus of P TH release is mediated by the adenyl cyclasecyclic ...
Abstract: The effect of various substances on parathyroid hormone (PTH) release was studied in vitro, in an attempt to determine whether adenosine 3′,5′–monophosphate (cyclic AMP) may be involved in regulating PTH release. Bovine parathyroid gland slices were incubated for 5 hr in tissue culture medium. The medium was changed each hour and analyzed for PTH concentration by radioimmunoassay. After the first 2 hr of incubation in medium with 1.5 mM calcium (Ca) concentration, the composition was changed to that of the test condition. Incubation with low Ca (0.75 mM) medium increased PTH release, and incubation with high Ca (3.0 mM) medium decreased PTH release significantly. PTH release was increased significantly by 10 mM dibutyryl cyclic AMP, 2 mM aminophylline, or 0.45 mM epinephrine. These in vitro observations a) strongly suggest that PTH release is influenced by cyclic AMP in the parathyroid cell, and b) further suggest that the known hypocalcemic stimulus of PTH release is mediated by the adenyl cyclasecyclic ...

Journal ArticleDOI
TL;DR: In this paper, a computer simulation of the cubic SiP2O7 superstructure was applied, where the predicted distances were treated as observations in a distance least-squares refinement, in which the positional coordinates of the atoms are varied until the calculated distances conform to the predicted values.

Journal ArticleDOI
TL;DR: The treatment of two patients who were first treated with EMG feedback training without positive response and who were treated later with the “temperature trainer” with positive response are described.

Journal ArticleDOI
TL;DR: The results indicate that the ligaments and facet joints play an important role in carrying loads, especially in bending and torsion, motion coupling is a function of segment orientation as well as of the intrinsic kinematic characteristics of a segment and during normal motions of the column, geometric nonlinearities are significant.

Journal ArticleDOI
TL;DR: It appears that suppression of idiotype is less reversible if antigen is administered soon after the antiidiotypic antibody, and the data suggest that escape from suppression is attributable to the generation of new precursor cells rather than to reactivation of suppressed cells.
Abstract: The appearance of an idiotypic specificity, present in anti-p-azophenylarsonate (anti-Ar) antibodies of all immunized A/J mice, ran be suppressed in adult mice by prior administration of an IgG fraction of rabbit antiidiotypic (anti-D) antiserum; anti-Ar antibodies arise but are of different idiotype Prolonged suppression was observed in earlier experiments, but antigen was first administered to adult mice only 2 wk or 9 wk after anti-D antibodies; subsequent escape from idiotypic suppression could have been masked by the capture of antigen by large numbers of memory cells having receptors of a different idiotype In the present experiments antigen was first administered at intervals up to 22 wk after the antiidiotypic antibody Suppression was maintained for 6 wk in all mice and for 5 mo in about half the mice tested It thus appears that suppression of idiotype is less reversible if antigen is administered soon after the antiidiotypic antibody The data suggest that escape from suppression is attributable to the generation of new precursor cells rather than to reactivation of suppressed cells The minimum dosage of antiidiotypic IgG required for effective suppression was about 2 mg The subcutaneous or intraperitoneal routes of inoculation of antiidiotypic IgG were equally effective When antiidiotypic antibody was administered 3 days after antigen no suppressive effects were observed There was partial suppression when antiidiotypic antibody was injected on the same day as the antigen Fab' and F(ab')2 fragments of antiidiotypic IgG had no suppressive effect Quantitative measurements revealed no significant differences among control and suppressed mice with respect to total concentration of precipitable anti-Ar antibodies produced

Journal ArticleDOI
TL;DR: Nearly all F 1 progeny of strain A mice formed CRI, indicating that failure of the other (non-A) parental strain to produce CRI is not attributable to the presence of a gene controlling the synthesis of a suppressor of CRI.
Abstract: The expression of an idiotype characteristic of anti-p-azophenylarsonate antibodies of all A/J mice was explored in F1 progeny, in other inbred strains, and in congenic mice. Of the strains tested only those closely related to A/J produced antibodies with the cross-reactive idiotype (CRI). None of the mice synthesized intermediate levels of CRI. No relationship between H-2 type and idiotype was noted. Congenic mice with a strain A background but a different H-2 type produced CRI in amounts quantitatively equivalent to those of strain A mice. Conversely, the presence of the H-2 genotype of strain A on an unrelated background was not associated with the formation of CRI. Nearly all F1 progeny of strain A mice formed CRI, indicating that failure of the other (non-A) parental strain to produce CRI is not attributable to the presence of a gene controlling the synthesis of a suppressor of CRI. NZB mice, which have the same heavy chain allotype as strain A, but are unrelated in origin, failed to produce CRI, although allotype has been shown to be linked to idiotype in congenic strains.

Journal ArticleDOI
TL;DR: In this article, the stochastic games of Shapley were considered and it was shown that under certain conditions, the game has a value and both players have an optimal strategy.
Abstract: In this paper, we consider the stochastic games ofShapley and prove under certain conditions the stochastic game has a value and both players have optimal strategies. We also prove a similar result for noncooperative stochastic games.

Journal ArticleDOI
TL;DR: In this article, the authors take up Feynman's challenge by arguing that things are perfectly all right in quantum mechanics, i.e., the deep mystery is what I have described and no one can go any further today.
Abstract: In concluding a popular exposition of probability in quantum mechanics {QM), Richard Feynman says 'But the deep mystery is what I have described, and no one can go any further today.' Thus Feynman poses a challenge by sanctioning an attitude common among scientists, the attitude that quantum physics is mysterious. Our probabilistic notions, our logic and the most basic guidelines of common sense seem to go awry when set in the quantum domain. I want to take up Feynman's challenge here by showing that this is not the case; that is, I want to argue that things are perfectly all right in QM. This is, however, a complex argument to make in general. And so I shall attempt to make it in two stages. In the first stage, which comprises Sections 1 to 4, I shall discuss a particular case in a way that will, I hope, allow for generalisation. Precisely because it has been so often discussed, the case I shall look at


Journal ArticleDOI
TL;DR: Administration of isoproterenol may facilitate both normal and depressed conduction in the A-V node and His-Purkinje system and may lead to partial or total reversal of second or third degree A-v block proximal to, in and distal to the His bundle.
Abstract: His bundle electrograms were obtained in 42 patients with heart disease before, during and after intravenous isoproterenol infusion. The group consisted of 5 patients with normal conduction and 37 patients with atrioventricular or intraventricular conduction disease. The A-H interval could be measured in 38 patients. In 30 patients with a normal A-H interval ( The following improvements in conduction were noted in the patients with second and third degree atrioventricular (A-V) block during isoproterenol infusion: (1) total reversal of second degree block proximal to the His bundle in two patients; (2) development of 2:1 conduction in one of three patients with third degree A-V block and “split” H potentials; and (3) development of 3:1 conduction in one of three patients with third degree A-V block distal to the His bundle. We conclude that administration of isoproterenol may facilitate both normal and depressed conduction in the A-V node and His-Purkinje system. This effect may lead to partial or total reversal of second or third degree A-V block proximal to, in and distal to the His bundle.

Journal ArticleDOI
TL;DR: Ribulose-5-P kinase from the pea plant has a high apparent affinity for ATP and is unaffected by energy charge levels, and apparently the residual dark activity of this light-activated reductive pentose phosphate pathway enzyme is reduced by the product of the dark-activated enzyme glucose- 5-P dehydrogenase.