Showing papers by "McMaster University published in 1982"
TL;DR: In this paper, an algorithm for the calculation of the average properties of an atom in a molecule is described. But this algorithm is restricted to the case where the atom is defined within the topological theory of molecular structure, a theory which defines atoms, bonds, structure and structural stability in terms of a system's charge distribution.
Abstract: This article describes an algorithm for the calculation of the average properties of an atom in a molecule. The atom is defined within the topological theory of molecular structure, a theory which defines atoms, bonds, structure, and structural stability in terms of the topological properties of a system's charge distribution. The average properties of the atom so defined are uniquely determined by quantum mechanics. Results for a number of hydrocarbon molecules, obtained by the program PROAIM (properties of atoms in molecules) which implements this algorithm, are given. In general, this program enables one to calculate the average energy of an atom in a molecule to an accuracy of ±1 kcal/mol.
1,250 citations
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TL;DR: This paper found that male sexual jealousy was the leading substantive issue in social conflict homicides in Detroit and a cross-cultural review of adultery law revealed remarkable conceptual consistency: unauthorized sexual contact with a married woman is a crime and the victim is the husband.
787 citations
TL;DR: The stable-carbon isotope ratios for the flesh of marine and terrestrial animals from Canada's Pacific coast differ by 7.9 � 0.4 per mil, reflecting the ∼ 7 per mil difference between oceanic and atmospheric carbon.
Abstract: The stable-carbon isotope ratios for the flesh of marine and terrestrial animals from Canada's Pacific coast differ by 7.9 +/- 0.4 per mil, reflecting the approximately 7 per mil difference between oceanic and atmospheric carbon. This difference is passed on to human consumers. The carbon isotopic values (delta(13)C) for human collagen thus yield direct information on the relative amounts of marine and terrestrial foods in prehistoric diets.
662 citations
TL;DR: It is suggested that allergen-induced late asthmatic responses can be associated with an increase in bronchial responsiveness to histamine by mechanisms other than a reduction in baseline airway caliber alone.
Abstract: Allergen-induced late asthmatic responses are associated with an increase in bronchial responsiveness to histamine. We have examined the relationship between the magnitude of the late asthmatic response and the magnitude and duration of increased histamine responsiveness. Allergen inhalation tests were carried out in 12 asthmatic subjects to induce a mild early asthmatic response (16% to 40% reduction in FEV 1 in the first hour after allergen inhalation); the response was followed over 8 hr to identify the occurrence and magnitude of any late asthmatic response (maximum fall in FEV 1 from baseline between 3 and 8 hr). The provocation concentration of histamine causing a decrease in FEV 1 of 20% (PC 20 ) was measured before and after inhalation of allergen. The magnitude of decrease in PC 20 correlated with the magnitude of the late asthmatic response as measured by the percent fall in FEV 1 (r = 0.8, p 20 was from 2 to 74 days and this also correlated with the magnitude of the late response (r = 0.53, p 1 , maximal expiratory flow-volume curves (on air and He-O 2 ), and histamine responsiveness were also measured before and at intervals after allergen inhalation. Four of seven subjects still had a reduction in PC 20 when the TLC, RV, FEV 1 , maximal expiratory flow-volume rates on air (V 50 air) and He-O 2 (V 50 He-O 2 ) (measured at an absolute volume corresponding plus 50% of control vital capacity) and ratio of V 50 He-O 2 to V 50 air were back t preallergen inhalation levels. In two of these subjects volume of isoflow was also back to ±10% of preallergen inhalation levels when the PC 20 was still significantly reduced. The results suggest that allergen-induced late asthmatic responses can be associated with an increase in bronchial responsiveness to histamine by mechanisms other than a reduction in baseline airway caliber alone.
620 citations
TL;DR: The effects of training in a multistage "complete process of creative problem solving" on attitudes and behaviors of individuals were assessed both immediately after training and return to work as mentioned in this paper.
306 citations
University of Maryland, Baltimore1, University of Alabama at Birmingham2, Harvard University3, Northwestern University4, University of California5, Michigan State University6, Georgetown University7, University of Mississippi8, University of California, Los Angeles9, University of Minnesota10, Yeshiva University11, University of Utah12, University of Texas Health Science Center at Houston13, University of Pittsburgh14, Mayo Clinic15, University of Pennsylvania16, Medical University of South Carolina17, McMaster University18, University of California, San Francisco19, Johns Hopkins University20, University of Michigan21, National Institutes of Health22
TL;DR: The beneficial effect of stepped-care treatment on persons with diastolic pressures who had no evidence of end-organ damage and were not receiving antihypertensive medication when they entered the study is supported.
Abstract: In the Hypertension Detection and Follow-up Program, 7825 (71.5 per cent) of the 10,940 participants had diastolic blood pressures averaging between 90 and 104 mm Hg on entry into the study and were designated Stratum 1. Half were referred to their usual source of care in the community (the referred-care group), and half were treated intensively in special clinics (the stepped-care group). Five-year mortality in the Stratum 1 patients given stepped care was 20.3 per cent lower than in those given referred care (P less than 0.01). Particularly noteworthy was the beneficial effect of stepped-care treatment on persons with diastolic pressures of 90 to 104 mm Hg who had no evidence of end-organ damage and were not receiving antihypertensive medication when they entered the study. This subgroup had 28.6 per cent fewer deaths at five years among those treated with stepped care than among those treated with referred care (P less than 0.01). These findings support a recommendation that in patients with mild hypertension, treatment should be considered early, before damage to end organs occurs.
303 citations
TL;DR: Results of animal experiments performed to evaluate a model of "overdose" deaths among heroin addicts suggest that conditioned drug-anticipatory responses, in addition to pharmacological factors, affect heroin-induced mortality.
Abstract: A model of "overdose" deaths among heroin addicts is proposed which emphasizes recent findings concerning the contribution of drug-associated environmental cues to drug tolerance. Results of animal experiments performed to evaluate this model suggest that conditioned drug-anticipatory responses, in addition to pharmacological factors, affect heroin-induced mortality.
254 citations
TL;DR: In this paper, the authors tested a series of hypotheses derived from the view that allegations of resemblance of newborns are motivated responses to the problem of uncertain paternity, and found that mothers tend to be biased toward maternal resemblance, whereas fathers betrayed skepticism or reserve about such allegations.
254 citations
TL;DR: Exposure of adult rainbow trout to low pH for 3 days resulted in progressive increases in heart rate, mean arterial blood pressure and haematocrit, which revealed an adrenergic component to the cardiovascular disturbance.
Abstract: Exposure of adult rainbow trout to low pH (4.0–4.5) for 3 days resulted in progressive increases in heart rate, mean arterial blood pressure and haematocrit. The haematocrit increase resulted from erythrocyte swelling, a reduction in plasma volume and a mobilization of erythrocytes from the spleen. Erythrocyte swelling probably resulted from plasma acidosis and a reduction in plasma ions (McDonald & Wood, 1981). There was an associated redistribution of body water from extracellular to intracellular compartments, but maintenance of total body water content. Erythrocyte mobilization was reflected in an increase in reticulocyte and erythrocyte counts, and a depletion of splenic blood reserves. Haemoconcentration caused large increases in blood viscosity, which contributed to the rise in blood pressure. Pharmacological analysis revealed an adrenergic component to the cardiovascular disturbance. These events are thought to play a key role in the toxic syndrome.
235 citations
TL;DR: In this paper, a method is proposed to derive the combination of slip systems that fulfills both the boundary conditions and the yield conditions for any particular crystal orientation, and the magnitude of the free shears as well as the resulting orientation change follow from kinematics.
234 citations
TL;DR: High-sensitivity measurements of infrared absorptions due to isolated lines broadened by air at atmospheric pressure are reported, and techniques for further increasing sensitivity are discussed.
Abstract: High-sensitivity measurements of infrared absorptions due to isolated lines broadened by air at atmospheric pressure are reported. Tunable diode lasers and harmonic techniques were employed to detect absorptions as small as 0.01% over path lengths up to 250 m through the open air. The limiting noise source is caused by a base line signal which varies with the optical alignment. The reported sensitivity is not a fundamental limit. Techniques for further increasing sensitivity are discussed.
TL;DR: Behavior modification techniques appear to have significant potential in reducing program dropout; however, there is a need to carefully investigate compliance-improving strategies before recommendations for a particular approach can be made.
TL;DR: There was a considerably higher incidence of structural abnormalities including central nuclei and atrophied fibres in the elite group than in the control group, which might possibly have been associated with the use of anabolic steroids by the Elite group.
Abstract: Muscle ultrastructure of a group of subjects possessing extreme hypertrophy was compared with that of a control group which had undergone 6 months of heavy resistance training. Two needle biopsies were taken from triceps brachii of two international calibre powerlifters and five elite bodybuilders. In addition, samples were taken from five healthy volunteers before and after 6 months of training of the elbow extensors. One biopsy was prepared for electron microscopy and analyzed stereologically, and the other was stained for myosin ATPase activity and photographed under the light microscope. Despite large differences in elbow extension strength and arm girth there was no significant difference in fibre areas or percentages of fibre types between the elite group and the trained controls. This suggests that the elite group possessed a greater total number of muscle fibres than the controls did. Mitochondrial volume density of the elite group was similar to that of the control group following training but significantly less (p<0.05) than the pretraining control measurements. Myofibrillar volume density was significantly lower and cytoplasmic volume density significantly higher in the elite group than in the trained controls. There was a considerably higher incidence of structural abnormalities including central nuclei and atrophied fibres in the elite group than in the control group, which might possibly have been associated with the use of anabolic steroids by the elite group.
TL;DR: For the processing of an item to be repeated, it is argued that the memory for a prior presentation of that item must not be readily accessible when the item is repeated as discussed by the authors.
TL;DR: It is concluded that during embryogenesis peripheral motor nerves are necessary initially for the proper growth of muscles and ultimately, for their survival.
Abstract: Cross-reinnervation studies performed ex ovo with newly hatched chicks demonstrate that peripheral motor neurons control the phenotypic characteristics of avian muscles. The present experiments were designed to determine whether or not nerves play a similar role during the initial expression of muscle fiber types. Previous experiments indicated that differentiation of specific fiber types occurs during the first week of embryogenesis, temporally coincident with the penetration of nerves within muscle masses. These observations suggested that peripheral nerves may be associated with the initial differentiation of fiber types. To test this hypothesis directly, anterior limb buds of the chick embryo were rendered aneurogenic by deletion of the brachial segment of the neural tube. To ensure a completely aneurogenic environment for developing brachial muscles, surgery was performed at day 2 in ovo before the exit of ventral root fibers. Experimental and control embryos from Stage (St) 25 (4.5 d) through St 45 (19d) were analyzed histochemically by a silver-cholinesterase reaction to detect nerves and by the myosin ATPase reaction, following alkali and acid preincubation, to determine the fiber type composition of the muscles. In addition, the total volume of aneurogenic and control muscles was compared. Results demonstrate that the characteristic myosin ATPase profiles of individual aneurogenic and innervated (control) muscles were identical throughout the entire period analyzed. Therefore, we conclude that these enzymic profiles are endogenously expressed and are not under neuronal control during early embryogenesis. Furthermore, the entire sequence of events from the migration of myogenic cells to the anterior limb bud through the division of the primary muscle masses to form individual brachial muscles proceeded on schedule in the absence of nerves. Since the growth of aneurogenic muscles was impaired, we conclude that during embryogenesis peripheral motor nerves are necessary initially for the proper growth of muscles and ultimately, for their survival. They are not involved, however, with either the initial formation or initial differentiation of individual brachial muscles.
TL;DR: An in vitro study of neural and myogenic control of human tracheal smooth muscle resulted in frequency-dependent biphasic responses: an initial atropine-sensitive cholinergic contraction followed by a nonadrenergic relaxation, consistent with a neural mechanism.
Abstract: An in vitro study of neural and myogenic control of human tracheal smooth muscle was undertaken. Over 80% of these had active tension and 13% had phasic contractile activity. Tonic and phasic activities were not reversed by indomethacin, 5,8,11,14-eicosatetraynoic acid, methysergide, mepyramine, atropine, or tetrodotoxin (TTX) but were blocked by the calcium antagonist verapamil. In some quiescent strips, tonic and/or phasic activity was induced by exposure to potassium-conductance blockers such as 4-aminopyridine (4-AP) and tetraethylammonium chloride (TEA). Electrical (field) stimulation resulted in frequency-dependent biphasic responses: an initial atropine-sensitive cholinergic contraction followed by a nonadrenergic relaxation. This biphasic response to low stimulus parameters (less than 0.5 ms, less than 15 Hz) was blocked by TTX and scorpion venom and enhanced by 4-AP and TEA, consistent with a neural mechanism. Relaxation responses to longer pulse durations (0.5-1 ms) were not blocked by TTX despite abolition of contraction nor were they enhanced by 4-AP and TEA, suggesting a nonneural mechanism. ATP, adenosine, arachidonate metabolites, histamine, 5-hydroxytryptamine, neurotensin, or vasoactive intestinal polypeptide were ruled out as possible nonadrenergic mediators. The nature and physiological significance of the nonneural inhibitory response remains unknown.
TL;DR: The results suggest that the plasma itself interacts with initially adsorbed proteins, that the role of fibrinogen adsorption in foreign-surface initiated thrombosis may need to be reevaluated and that trace proteins may be important in blood-material interactions.
Abstract: The deposition of proteins on blood-contacting surfaces is known to be a determining factor in subsequent thromboembolic events. The composition of the protein layers and how they change with time are unknown. To generate information relevant to these questions, the quantities of albumin, fibrinogen and IgG adsorbed on seven surfaces from human plasma as a function of time were measured using a tracelabeling method. Materials studied include several segmented polyether-urethanes, glass, siliconized glass (SG), polystyrene (PS) and polyethylene (PE). Fibrinogen, surprisingly, was not adsorbed from plasma to any of the hydrophilic surfaces. On PE and SG adsorption passed through an early maximum (before 2 min) then declined to near zero. Only on PS was adsorption substantial and constant with time. Albumin was also not detected on the hydrophilic surfaces. IgG but was adsorbed substantially on the hydrophobic surfaces. IgG was detected on all surfaces, although in relatively low surface concentrations. These results suggest: 1. that the plasma itself interacts with initially adsorbed proteins, 2. that the role of fibrinogen adsorption in foreign-surface initiated thrombosis may need to be reevaluated and 3. that since the major plasma proteins are only minimally adsorbed, trace proteins may be important in blood-material interactions.
TL;DR: In this paper, a statistical representation of seismic liquefaction is presented based on the postulate that pore water pressure increases are proportional to the dissipated seismic energy density, based on approximately fifty case histories.
Abstract: A statistical representation of seismic liquefaction is advanced based on the postulate that pore water pressure increases are proportional to the dissipated seismic energy density. The representation, based on approximately fifty case histories, relates the pore pressure increase to earthquake magnitude, distance to centre of energy release, initial effective overburden stressand standard penetration value. The model may be used for analysis ofseismic liquefaction risk. An example analysis for the ‘South of Market Zone’ in San Francisco is carried out in relation to earthquakes on the San Andreas fault.
TL;DR: It is concluded that sham feeding represents a useful technique for isolating the influence of diet palatability on food intake and is identified as one of the parameters that influences the magnitude of the sham feeding response.
TL;DR: The performance of models to estimate solar irradiance and its components is assessed using data for six Canadian stations for nine years (1968-1976) as discussed by the authors, with the focus on a model, the MAC model, which uses cloud information from different layers.
TL;DR: A kinetic model based on the free volume theory has been proposed for the polymerization of styrene in this article, which is capable of describing the course of polymerization in both bulk and solution, accounts for diffusion-controlled termination and propagation and gives a limiting conversion.
Abstract: A kinetic model based on the free volume theory has been proposed for the polymerization of styrene. The model, which is capable of describing the course of polymerization in both bulk and solution, accounts for diffusion-controlled termination and propagation and gives a limiting conversion.
TL;DR: It is demonstrated that a decrease in progesterone levels followed by increases in estradiol and PGF2 alpha are coincident with the formation of gap junctions which in turn may coordinate the increased uterine activity required for parturition.
Abstract: To study the temporal relationship between changes in hormone levels with the development of myometrial gap junctions, rats were sacrificed to collect uterine vein blood and uterine tissues daily from Day 15 to Day 20 of pregnancy, every 3 h on Day 21, during delivery, and 3 h after parturition. Levels of progesterone, estradiol and prostaglandin F2 alpha (PGF2 alpha) were measured by specific radioimmunoassay methods, and myometrial gap junctions were measured by quantitative electron microscopy. Levels of progesterone declined markedly on Day 19 of pregnancy, at least 60 to 70 h before the expected time of parturition and the decrease was more rapid in uterine tissue than in plasma. Levels of estradiol started to increase after Day 19, showed a marked rise on Day 21, and peaked at the time of parturition. Levels of PGF2 alpha also increased rapidly after Day 20, when progesterone levels had already dropped by 67% and 84% of Day 15 levels in plasma and tissue samples, respectively. Gap junctions, identified as 5- or 7-lined structures with a gap of about 2 nm at 100,000X magnification were present in the pregnant uterus. However, their number, size and area were increased significantly on Day 21 and during parturition. Increased numbers of gap junctions were still present in rats killed 3 h after parturition. These studies demonstrate that a decrease in progesterone levels followed by increases in estradiol and PGF2 alpha are coincident with the formation of gap junctions which in turn may coordinate the increased uterine activity required for parturition.
TL;DR: In this paper, a simple theoretical model was developed from first principles for the fluidelastic instability in heat exchanger tube bundles, and a series of experiments were conducted to verify the basic assumption that only a single tube need be modeled in a flow channel which preserves the basic geometry of the array.
Abstract: A simple theoretical model has been developed from first principles for the fluidelastic instability in heat exchanger tube bundles. A series of experiments were conducted to verify the basic assumption that only a single tube need be modeled in a flow channel which preserves the basic geometry of the array. The mechanism of instability is found to be one of flow redistribution due to tube motion and a phase lag resulting from fluid inertia. Quite good agreement is found with available experimental data for a parallel triangular array without the need for empirical fluid force coefficients. The model includes the effects of tube array pattern and pitch.
TL;DR: It is suggested that facial expressions are mediated more by the right hemisphere than by the left, and left-handers show no consistent asymmetries.
TL;DR: It is shown that two trees of the same type are O( n) and O(n log n) distance apart, for unlabelled and labelled trees respectively, the basis for the distance measure is the interchange or rotation tree transformation.
TL;DR: The present data indicate that the teleost red blood cell does play a role in plasma H CO 3 − dehydration and CO 2 excretion, and therefore opposes the theory of Haswell & Randall (1978) that the erythrocyte is functionally impermeable to HCO 3 − .
Abstract: Severe experimental anaemia caused a rise in P co co2 and an associated fall in pH (respiratory acidosis) in arterial and venous blood of both flounder and trout in vivo . In some trout, but not in flounder, there was also a rise in blood lactate, indicating metabolic acidosis. In vitro , blood buffer capacities declined with haematocrit, a factor which contributed to the extent of the acidoses in vivo . However, haematocrit did not influence the p K 1 of the plasma HCO 3 − /H 2 CO 3 system or the actual measurement of blood pH. The Donnan ratio for HCO 3 − varied linearly with pH over the range 7.0–7.6, indicating a passive distribution of HCO 3 − across the trout erythrocyte. The present data, together with other recent results, indicate that the teleost red blood cell does play a role in plasma HCO 3 − dehydration and CO 2 excretion, and therefore opposes the theory of Haswell & Randall (1978) that the erythrocyte is functionally impermeable to HCO 3 − .
Abstract: A new boundary scheme for atomic-level computer simulations in solid mechaisms has been developed which is based on the finite-element method and which provides several advantages over previous boundary schemes. This has been applied to the simulation of (001) plane two-dimensional cracks in ac-Fe having crack line directions of [010] and [110]. Significant differences between the cracks in these two directions were observed. Lattice-trapping limits and some information on the magnitude and shape of the crack-tip displacement field is provided for both cases. No dislocations were emitted at low temperatures, but warming the model to 400 K apparently resulted in the emission of a dislocation from the crack-tip.
TL;DR: The span of apprehension task was found to be significantly correlated with a measure of thought disorder that assesses resistance to associative distractors and two neuropsychological tests--the Trail-Making Test from the Halstead-Reitan battery and the Digit Symbol Substitution Test--during the testing session conducted while the subjects were partially recovered.
Abstract: Schizophrenic subjects were administered the span of apprehension task, which is a measure of visual information processing; two neuropsychological tests; and measures of specific aspects of thought disorder and general clinical state. The measures were administered both when patients were acutely disturbed and when they were partially recovered. Normal control subjects were tested over a comparable 12-week interval. Improvements in both overall clinical condition and specific aspects of thought disorder occurred in the schizophrenic patients during this time. The patients, however, continued to show impaired information processing, indicating that the span of apprehension task is sensitive to schizophrenic dysfunction across wide variations in clinical state and, therefore, may be a marker of vulnerability to schizophrenia. The span of apprehension task was found to be significantly correlated with a measure of thought disorder that assesses resistance to associative distractors and two neuropsychological tests—the Trail-Making Test from the Halstead-Reitan battery and the Digit Symbol Substitution Test—during the testing session conducted while the subjects were partially recovered.
TL;DR: Examination of the four nucleoside 3',5'-bisphosphate donors pUp, pCp, pAp and pGp with a common acceptor ApApU indicated that in the case of poor ligation little of the intermediate adenylated donor was formed.
Abstract: In order to make efficient use of T4 RNA ligase in a program involving chemical-enzymatic oligoribonucleotide synthesis, the sequence effects of the acceptor oligomer have been refined. The reaction of the donor molecules pCp and pUpUpUpCp with a series of trinucleoside diphosphates ApApN, CpNpA and NpCpA (where N = U, C, A or G) was examined. High-performance liquid chromatography was used for simultaneous analysis of all substrates, intermediates and products. For all trinucleoside bisphosphates tested a substantial amount of the intermediate A(5')pp(5')Cp or A(5')pp(5')UpUpUpCp was observed. This indicated that the extent of ligation was dependent upon sequence of the acceptor molecule and not upon adenylation of the donor. Conversely, examination of the four nucleoside 3',5'-bisphosphate donors pUp, pCp, pAp and pGp with a common acceptor ApApU indicated that in the case of poor ligation little of the intermediate adenylated donor was formed.