Showing papers by "University of Illinois at Chicago published in 1975"

Fundamentals of Error-Correcting Codes

Abstract: Preface 1. Basic concepts of linear codes 2. Bounds on size of codes 3. Finite fields 4. Cyclic codes 5. BCH and Reed-Soloman codes 6. Duadic codes 7. Weight distributions 8. Designs 9. Self-dual codes 10. Some favourite self-dual codes 11. Covering radius and cosets 12. Codes over Z4 13. Codes from algebraic geometry 14. Convolutional codes 15. Soft decision and iterative decoding Bibliography Index.

Angiotensin I converting enzyme.

Abstract: Many of the properties of angiotensin I converting enzyme or kininase II (ACE) have been discussed in extenso in the literature. The mode of action of ACE inhibitors has been studied in experimental animals and used clinically in millions of patients. The relatively few side effects have also been amply scrutinized. Nevertheless, some of the basic properties of this enzyme remain unexplained. For instance, although ACE was first considered to be a carboxypeptidase-type enzyme (peptidyl dipeptidase or dipeptidyl carboxypeptidase) (1,2) its actions go beyond cleaving dipep-tides from the free C-terminal end of peptide substrates. ACE inactivates substance P in spite of its blocked C-terminus, primarily by releasing the C-terminal tripeptide Gly-Leu-Met-NH2 (3). The blocked C-terminal tripep-tide, Arg-Pro-Gly-NH2, is also released from the luteinizing hormone releasing hormone (LHRH) (A). ACE, surprisingly, also cleaves the protected the N-terminal tripeptide

Müller muscle-conjunctiva resection. Technique for treatment of blepharoptosis.

Abstract: A new technique for resecting the Muller muscle and the conjunctiva for correction of blepharoptosis has been developed. The operation is performed on all patients in whom a 10% phenylephrine hydrochloride solution instilled in the conjunctival cul-de-sac will elevate the blepharoptotic eyelid to a cosmetically acceptable level. The results of the surgery have been satisfactory in 27 of 28 operated eyelids.

A behavioral-educational alternative to drug control of hyperactive children.

Abstract: A behavioral procedure for controlling hyperactivity without inhibiting academic performance is described Using a time-sample observational method, the hyperactivity displayed by three school children was recorded during math and reading classes Concurrently, math and reading performances were measured The study consisted of two baselines, one while the children were on medication and the second while they were off medication A multiple-baseline design across the two academic subject matters was used to assess the behavioral intervention, which consisted of token reinforcement for correct academic responses in math and subsequently math and reading Discontinuation of medication resulted in a gross increase in hyperactivity from 20% to about 80%, and a slight increase in math and reading performance Introduction of a behavioral program for academic performance, during no medication, controlled the children's hyperactivity at a level comparable to that when they were on drugs (about 20%) At the same time, math and reading performance for the group jumped from about 12% during baseline to a level of over 85% correct Each child performed behaviorally and academically in an optimal manner without medication Contingency management techniques provided a feasible alternative to medication for controlling hyperactivity in the classroom while enabling the children to grow academically

Dual atrioventricular nodal pathways. A common electrophysiological response.

Abstract: Evidence of dual atrioventricular nodal pathwats (a sudden jump in H1-H2 at critical A1-A2 coupling intervals) was shown in 41 out of 397 patients studied with atrial extrastimulus techniques. In 27 of these 41, dual pathways were demonstrable during sinus rhythm, or at a cycle length close to sinus rhythm (CL1). In the remaining 14, dual pathways were only demonstrated at a shorter cycle length (CL2). All patients with dual pathways at cycle length who were also tested at cycle length (11 patients) had dual pathways demonstrable at both cycle lengths. In these 11 patients both fast and slow pathway effective refractory periods increased with decrease in cycle length. Twenth-two of the patients (54%) had either an aetiological factor strongly associated with atrioventricular nodal dysfunction or one or more abnormalities suggesting depressed atrioventricular nodal function. Dvaluation of fast pathway properties suggested that this pathway was intranodal. Seventeen of the patients had previously documented paroxysmal supraventricular tachycardia (group 1). Eight patients had recurrent palpitation without documented paroxysmal supraventricular tachycardia (group 2), and 16 patients had neither palpitation nor paroxysmal supraventricular tachycardia (group 3). Echo zones were demonstrated in 15 patients (88%) in group 1, no patients in group 2, and 2 patients (13%) in group 3.

Effect of Glucocorticoids on Function of the Parathyroid Glands in Man

Abstract: This study evaluated the effect of chronic and acute administration of excessive doses of glucocorticoids on parathyroid hormone (PTH) secretion in man. Eleven patients receiving 15 to 80 mg prednisone daily for 1 to 50 months had normal serum calcium (Ca) but serum PTH levels significantly greater than those of 19 controls. Eleven normal adult men received 200 mg cortisol iv over a 4-hr period, during and following which blood was obtained frequently for serum Ca and PTH. Serum Ca remained normal in all patients. PTH began to rise by ¼ hr, was 152 ± 18.5% of baseline by 1 hr, reached 172 ± 18.5% of baseline by 3 hr, and then gradually declined to 126 ± 12.6% of baseline at 6 hr. These data indicate that in man, as in the rat (shown in previous studies), increase in cortisol with its hypocalcemic effect, causes stimulation of the parathyroid glands (PTG) with increased PTH secretion, which prevents significant hypocalcemia. This parathyroid response is prompt (as indicated by the cortisol infusion study),...

Antiestrogen action in the uterus: biological ineffectiveness of nuclear bound estradiol after antiestrogen.

Abstract: These studies attempt to analyze the basis of the estrogenic and antiestrogenic action of three· nonsteroidal clomiphene-type compounds as monitored by their ability to bind to immature rat uterine cytoplasmic estrogen receptor, transfer receptor sites to the nucleus, and elicit estrogenic responses (increased uterine weight and induction of the synthesis of a specific uterine protein, called induced protein, or “IP”), and by their ability to antagonize the effects of estradiol on these receptor interactions and uterine responses. Both CI-628 (CI) and U-ll.lOOA (UA) [50 μg] elicit slight IP induction at 1–2 h and give pronounced uterine weight increases at 24 h but feeble increases at 72 h (3 single daily injections). Both bind to cytosol, and effect the transfer of receptor sites to the nucleus, which may account for the estrogenicity of these compounds. Both CI and UA give rapid (by 2–4 h), prolonged (for over 24 h), and complete blockage of estradiol-stimulated induction of IP synthesis. Likewise, anti...

A New Linear-Time ``On-Line'' Algorithm for Finding the Smallest Initial Palindrome of a String

Abstract: Despite significant advances in linear-time scanning algorithms, particularly those based wholly or in par t on either Cook's linear-time simulation of two-way deterministic pushdown automata or Weiner's algorithm, the problem of recognizing the initial leftmost nonvoid palindrome of a string in time proportional to the length N of the palindrome, examining no symbols other than those in the palindrome, has remained open. The present algorithm solves this problem, assuming tha t addition of two integers less than or equal to N may be performed in a single operation. Like th e Knuth-Morris-Prat t algorithm, i t runs in time independent of the size of the input alphabet. T h e algorithm as presented finds only even palindromes. However, an extension allows one to recognize the initial odd or even palindrome of length 2 or greater. Other easy extensions permit the recognition of strings (wwR) * of even palindromes and of all the initial palindromes. I t appears possible tha t further extension may be used to show tha t (wwR) * is in a sense recognizable in real time on a reasonably defined random access machine. xEv WORDS AND PHa~SES: linear-time algorithm, on-line recognition, palindrome CR CATEGORIES: 5.22, 5.25, 5.30

Transparency of pair-correlated, random distributions of small scatterers, with applications to the cornea*

Abstract: We consider transmission through pair-correlated random distributions of lossless dielectric (globular, cylindrical, or plate-like) scatterers with length parameter a and average spacing small compared to wavelength. Each optical particle is centered in a tough adherent transparent coating whose outer surface (sphere, cylinder, or slab) has radius b ≥ a. The corresponding attenuation coefficients β∝Wm involve an integral of the appropriate radial-distribution function. Using the scaled-particle equations of state and statistical-mechanics theorems, we evaluate Wm explicitly as a rational function of the volume fraction w of the fluid of rigid b particles. We obtain βm=β0Wm with β0 as the uncorrelated value; W3(w) for spheres decreases more rapidly with increasing w than W2 for cylinders, and W2 decreases faster than W1, the result for slabs. We apply the results for cylinders in terms of W2 to the problem of the transparency of the cornea (whose collagen fibers are the scatterers), as posed by Maurice. The value w ≈ 0.6 gives good accord with the essentials of the data for the transparency of the normal cornea, and the opacity that results from swelling is accounted for by corresponding smaller values of w. Thus, the normal cornea is modeled as a very densely packed two-dimensional gas, with gas-particle (mechanical) radius about 60% greater than the fiber (optical) radius.

Structural transitions of deoxyribonucleic acid in aqueous electrolyte solutions. II. The role of hydration.

Abstract: The data and approach reported in paper I (Hanlon et al., 1975, preceding paper) have been used to calculate the fractional changes in secondary structure of calf thymus deoxyribonucleic acid which occur in aqueous solutions as a function of the concentration of NaCl, KCl, LiCl, CsCl, and NH4Cl. There is a continuous loss in the "B" character of the nucleic acid with concomitant production of the C and, in some instances, an A form, as well, as the salt concentration increases. Sedimentation velocity studies suggest that there is an accompanying change in the hydrodynamic characteristics of the DNA molecules, as well. Utilizing the existing hydration data in the literature (Hearst and Vinograd, 1961a,b; Hearst, 1965; Tunis and Hearst, 1968a; Cohen and Eisenberg, 1968; Falk et al., 1962, 1963a,b), we have found that a gradual loss of "B" character and a decrease in the frictional coefficient of DNA occur as the net hydration of DNA is reduced from the fully hydrated from (60-80 mol of H2O/mol of nucleotide) to values of ca. 12-14 mol of H2O/mol of nucleotide. Below that value, a more precipitous decrease in these properties occurs. Extrapolation of the linear relationship observed between the fractional B content and the net hydration in the latter regions yield values of ca. 18 mol of H2O/mol of nucleotide at 100% B and ca. 4 mol of H2O/mol of nucleotide at 0% B (i.e., 100% C or C + A) for the alkali metal salts of DNA. The ammonium salt retains somewhat more H2O in the C and A forms (ca. 7). These results together with the hydration site assignments of Falk et al. (1962, 1963a,b) are interpreted in terms of a hydration model for DNA in aqueous solution in which an intact primary hydration shell of ca. 18 mol of H2O/mol of nucleotide is required for the maintenance of the "B" conformation. Removal of all but those water molecules solvating the phosphate groups results in the conversion to the C forms, predominantly, with a small amount of A structure formed as well in some salts. The accompanying changes in the sedimentation coefficients suggest that the DNA molecule assumes a more compact and/or flexible form under these conditions in which it is mainly in the C and A structures. The combination of these two events which ensue upon dehydration create a polymeric structure which can be more easily packaged in biological systems.

Interscalene cervical plexus block: a single-injection technic.

Abstract: A review of the anatomy of the cervical plexus and surrounding structures suggests a single-injection technic which simplifies anesthesia of the cervical plexus and increases the margin of safety in this procedure. Used by the authors, the technic has been successful in 97 percent of over 100 cases.

Demonstration of sustained sinus and atrial re-entry as a mechanism of paroxysmal supraventricular tachycardia.

Abstract: Electrophysiological studies in five patients with documented (4) or suspected (1) paroxysmal supraventricular tachycardia (PSVT), suggested sinus or atrial reentrance (SR or AR). Two of the patients had preexcitation, three had evidence of atrial enlargement, and all had organic heart disease. The following observations supported a diagnosis of SR and AR; 1) induction of sustained PSVT with atrial extrastimulus technique allowing definition of an echo zone; 2) induction of sustained PSVT during constant rapid atrial pacing at a rate less than that producing A-V nodal Wenckebach periods, or producing normalization of QRS complex in patients with pre-excitation: 3) P waves preceding each QRS during PSVT with an A-H interval appropriate for the rate of the PSVT; 4) antegrade P wave morphology during PSVT, a normal high to low sequence of right atrial activation (SR), or P wave morphology and atrial activation sequence different from sinus (AR); 5) lack of correlation of PSVT induction with critical A-H interval. The rates of induced sustained PSVT ranged from 114 to 143 beats/min, and were similar to those observed during spontaneous episodes of PSVT in the four patients. PSVT could be terminated with critically timed extra-stimuli or carotid massage. In conclusion, SR and AR appear to be mechanisms of spontaneous PSVT in man. Rates of SR and AR PSVT tend to be relatively slow.

Structural transitions of deoxyribonucleic acid in aqueous electrolyte solutions. I. Reference spectra of conformational limits.

Abstract: The circular dichroism properties of calf thymus DNA have been examined at 27 degrees over the wavelength range of 215-300 nm in aqueous solutions of NaCl, KCl, LiCl, CsCl, and NH4Cl at pH 7. The concentrations of these electrolytes were varied from 0.01 to ca. 5-10 m. The spectral changes induced by changes in concentration of NaCl and KCl and all but the highest concentrations of NH4Cl as well as lower concentrations of Cstcl and LiCl could be represented by a common two-state transition involving the conversion of the typical conservative spectrum commonly seen in dilute solutions of these salts to a nonconservative spectrum similar to that obtained by Tunis-Schneider and Maestre ((1970), J. Mol. Biol. 52, 521) for the C form of DNA. At higher concentrations of CsCl, LiCl, and NH4Cl, an additional component, resembling an A type spectrum, was required to account for the observed CD changes with changing concentration of electrolyte. Relying on the published spectra of the B, the C, and the A forms of DNA by Tunis-Schneider and Maestre for identification and approximate values of the molecular ellipticities of these forms, we have analyzed these spectral transitions by two least mean squares methods in order to obtain accurate reference spectra of aqueous "B", C, and "A" conformations of calf thymus DNA. The results obtained suggest that although the C form in solution is identical with that obtained in film, the aqueous B conformational limit is not identical with the crystallographic Watson-Crick structure. In addition, the A form generated in solution under our experimental conditions appears to be more similar to that assumed by low molecular weight Escherichia coli DNA at 75% relative humidity rather than calf thymus DNA at the same relative humidity.

The Human Society

Abstract: This chapter discusses the social aspects of engineering design. Each new discovery or technological advance influenced the growth of a society in subtle and sometimes far-reaching ways. The polished stone axe permitted the clearing of forest, encouraging the spread of settled communities. The invention of the plough and the sickle enabled men to farm larger areas, grow more food, and support larger populations with more time available for leisure and the pursuit of the arts and sciences. All of the technological advances in man's history occurred because they promised some increased ability or improvement in his way of life. Stability can be reached when there occurs a balance of power between those that control capital, the technostructure, and those groups responsible for fostering and protecting human resources.

Induction of concepts in the predicate calculus

Abstract: Positive and negative instances of a concept are assumed to be described by a conjunction of literals in the predicate calculus, with terms limited to constants and universally quantified variables. A graph representation of a conjunction of literals, called a "product graph", is introduced. It is desirable to merge positive instances by generalization, while maintaining discrimination against negative instances. This is accomplished by an induction procedure which operates on the product graph form of these positive and negative instances. The correctness of the procedure is proven, together with several related results of direct practical significance. This work is directed to the goal of providing a formal model for the inductive processes which are observed in artificial intelligence studies in specialized areas.

The distribution of chance congruence coefficients from simulated data

Abstract: All attempts to study the stability of factors depend on having some useful statistic that measures the degree of similarity between factors. This study attempts to provide some normative data about the distribution of one measure of similarity, the congruence coefficient, through a Monte Carlo technique. The matching of “chance” factor patterns was done by the method of Tucker. Statistical tests of the results, based on similarities of the method to canonical and multiple correlation, seemed satisfactory. The tabled results can be used as guides to the significance of congruence coefficients for some cases. The consistencies of the data indicate that a functional resolution may be possible, but none was found.

Role of Adrenergic Stimuli in Parathyroid Hormone Secretion in Man

Abstract: The role of adrenergic stimuli in the secretion of parathyroid hormone (PTH) in man was evaluated. Intradermal injections of isoproterenol, 0.15 mg, or epinephrine, 0.3 mg, caused significant prompt increases in serum PTH levels. These increases were not accompanied by any changes in serum calcium (Ca) during the period of observation. Phenylephrine, 1.5 mg, intradermally, did not cause any significant changes in serum PTH or serum Ca. Propranolol infusion alone significantly inhibited the basal secretion of PTH. This inhibition by propranolol was overcome by isoproterenol administration. The results indicate that 1) beta adrenergic agents increase PTH secretion whereas alpha adrenergic agents have no effect, 2) beta adrenergic stimuli probably play an important physiological role in basal PTH secretion in man.

An Analysis of the Electromyogram by Fourier, Simulation and Experimental Techniques

Abstract: The electromyogram of a single motor unit is studied by considering it as a time function defined by a convolution integral where a point process input passes through a filter whose impulse response is the shape of a single motor unit action potential. The interspike intervals are assumed to be normally distributed, independent random variables. Simulation is performed on a digital computer. The theoretical analysis shows that the absolute value of the ensemble average of the Fourier transform of the simulated EMG approaches the absolute value of the Fourier transform of the motor unit potential. This has been confirmed by simulation except at the very low end of the spectrum. These results are compared with the Fourier transforms of the recorded surface EMG data from human muscles.

H-V interval in patients with bifascicular block (right bundle branch block and left anterior hemiblock). Clinical, electrocardiographic and electrophysiologic correlations.

Abstract: Electrophysiologic studies were performed in 119 adults with chronic bifascicular block manifested by right bundle branch block and left anterior hemiblock. The H-V interval was normal in 86 patients and prolonged in 33. The following clinical variables were more frequent (P less than 0.05) in patients with a prolonged H-V interval: cardiac third sound, mitral systolic murmur, cardiomegaly on chest roentgenogram, congestive heart failure and cardiac functional class III or IV (New York Heart Association criteria). The following differences in the electrocardiographic and electrophysiologic findings were found: Patients with a prolonged H-V interaval had a longer mean P-R interval, QRS duration and A-H interval (P less 0.02). All patients were followed up prospectively in a cardiac conduction disease clinic after initial evaluation. The mean follow-up periods were (mean plus or minus standard error of the mean) 514 plus or minus 49 and 563 plus or minus 34 days for the patients with a prolonged and normal H-V interval, respectively. Progression of conduction disease occurred in three patients (4 percent) with a normal H-V interval and in four (12 percent) with a prolonged interval. The cumulative 3 year mortality rate for the entire group was 25 percent. The patients with a prolonged H-V interval had a higher cumulative 2 year mortality rate than those with a normal H-V interval but the difference was not statistically significant. In summary, a prolonged H-V interval was often associated with serious myocardial dysfunction and a high mortality rate. The risk of progression of conduction disease was slight with either a prolonged or a normal H-V interval during this relatively short follow-up period.

New manifestations of dual A-V nodal pathways.

Abstract: Electrophysiological studies with extrastimulus technique demonstrated evidence of dual A-V pathways in two patients with paroxysmal supraventricular tachycardia (PSVT). In case one, the second P of paced Wenckebach sequences was followed by two conducted QRS complexes without an intervening P wave. The A-H of the first and second QRS were consistent with the fast and slow pathway conduction times. The second QRS was followed by an atrial echo and PSVT, suggesting that the first pathway was available for retrograde propagation following the second QRS. In case two, PSVT was induced with atrial extrastimulus, followed by development of A-V dissociation. The two cases suggest the following conclusions: (1) dual A-V nodal pathways may allow the occurrence of double antegrade conduction of one P; (2) the atria are not necessary for A-V nodal circus movements in "dual pathway" A-V nodal reentrant PSVT.

Mechanisms of Paroxysmal Supraventricular Tachycardia

Abstract: Paroxysmal supraventricular tachycardia (PSVT) is a common arrhythmia in patients with and without organic heart disease. It has generally been believed to reflect either reentrant mechanisms or rapid firing of ectopic foci. Recent clinical and experimental observations have suggested that most PSVT appears to reflect reentrance. 1-6 In man, the occurrence of reentrance has been demonstrated in the sinus node, 7-9 atrium, 9 atrioventricular node, 1-6 and possibly the His bundle. 10 Longitudinal dissociation of a conducting structure (for example, the atrioventricular node) allows reentry to occur 11-14 (Fig 1, left). With dissociation into two pathways, a premature impulse encounters refractoriness (unidirectional block) in one pathway and conducts slowly in the other pathway. The previously blocked pathway recovers for retrograde conduction during the period of slow conduction. If the two pathways are connected by a final common pathway, the impulse can reenter the previously blocked pathway and return to the chamber of origin. While conducting retrograde,

Genetic determinant of lithium ion distribution. An in vitro and in vivo monozygotic-dizygotic twin study.

Abstract: • In previous research, evidence was provided of genetic control of in vitro red blood cell (RBC) uptake of lithium ion following a 24-hour incubation using a monozygotic (MZ)-dizygotic (DZ) twin study method. To extend these data, in vitro RBC lithium ion concentrations were assessed for five MZ and five DZ twin pairs. To extend this line of research on genetic control of lithium ion distribution to in vivo conditions, these twin pairs were administered lithium carbonate for seven days during which time RBC and plasma lithium ion concentrations were assessed. In this limited sample, the data provide evidence of genetic control of distribution of lithium ion across the RBC membrane in vivo as well as of in vitro RBC uptake of lithium ion.

Peripheral control of drinking: gastrointestinal filling as a negative feedback signal, a theoretical and experimental analysis.

Abstract: The studies described here investigated the hypothesis that the osmotic postingestional satiety signal proposed by McCleary operates through a mechanism related to gut filling rather than by osmotically induced shifts of fluid from osmoreceptors in the brain. A control theory model is presented, which was designed to make quantitatively explicit the hypothesis under question. The results showed that when mannitol, which is not absorbed from the intestine, is added to a highly palatable saccharin-glucose mixture, the amount of fluid consumed decreased in inverse proportion to the mannitol concentration. Mannitol was also shown to block fluid absorption from the intestine at a low concentration (approximately .070 M) and at higher concentrations to lead to a net flux of fluid into the intestinal lumen. It was also shown that mannitol in concentrations that reduced the intake of the palatable solution did not induce thirst when the animals were in water balance. It did induce thirst, however, when the animals were tested in a state of negative water balance. The results of these studies, considered as a whole, support the view that McCleary's osmotic postingestional satiety signal acts as an intestinal distention signal rather than by inducing thirst. The model is found to be reasonably accurate as a first approximation, and suggestions are made for improvements.

Sinus nodal responses to atrial extrastimuli in patients without apparent sinus node disease.

Abstract: In 36 patients without sinus node disease scanning with an atrial extrastimulus (A2) was performed during sinus rhythm with the sinus cycle length measured in milliseconds. Zones of nonreset due to interference, reset, interpolation and sinus echoes were defined by noting the timing of the first response after A2. Zones were defined in terms of their longest and shortest A1-A2 coupling intervals (in milliseconds). A zone of nonreset was found in 12 of 12 patients in whom A2 was delivered late. The mean cycle length in these 12 patients was 779 msec, with a mean zone of nonreset of 779 to 585 msec (25 percent of cycle length). All 36 patients (100 percent) had a zone of reset. The mean cycle length in these 36 patients was 803 msec with a zone of reset from 692 to 319 msec (46 percent of cycle length). Seven of 36 patients (19 percent) had a zone of interpolation. The mean cycle length in these seven patients was 754 msec, with a mean zone of interpolation of 344 to 279 (9 percent of cycle length). Four of 36 patients (11 percent) had a zone of sinus echoes. The mean cycle length in these four patients was 870 msec, with a mean zone of echoes from 350 to 313 msec (4 percent of cycle length). Calculated sinoatrial conduction time ranged from 40 to 153 msec (mean +/- standard deviation 92 +/- 30 msec). Shortening of the cycle length with atrial pacing increased the number of patients with zones of interpolation and echoes. In conclusion, zones of nonreset and reset are found in all patients with normal sinus nodal function, whereas zones of interpolation and echoes are much less common. Sinoatrial conduction time is surprisingly long in patients without apparent sinus node disease.