Showing papers by "Drexel University published in 1981"
TL;DR: Cocitation analysis of authors offers a new technique that might contribute to the understanding of intellectual structure in the sciences and possibly in other areas to the extent that those areas rely on serial publications.
Abstract: It is shown that the mapping of a particular area of science, in this case information science, can be done using authors as units of analysis and the cocitations of pairs of authors as the variable that indicates their “distances” from each other. The analysis assumes that the more two authors are cited together, the closer the relationship between them. The raw data are cocitation counts drawn online from Social Scisearch (Social Sciences Citation Index) over the period 1972–1979. The resulting map shows (1) identifiable author groups (akin to “schools”) of information science, (2) locations of these groups with respect to each other, (3) the degree of centrality and peripherality of authors within groups, (4) proximities of authors within group and across group boundaries (“border authors” who seem to connect various areas of research), and (5) positions of authors with respect to the map's axes, which were arbitrarily set spanning the most divergent groups in order to aid interpretation. Cocitation analysis of authors offers a new technique that might contribute to the understanding of intellectual structure in the sciences and possibly in other areas to the extent that those areas rely on serial publications. The technique establishes authors, as well as documents, as an effective unit in analyzing subject specialties.
1,104 citations
TL;DR: It is concluded that 3000 rad in two weeks is at least as effective as 5000 rad in four weeks in the palliation of brain metastases, even in this relatively favorable patient population.
Abstract: The palliative effectiveness of a short, intensive course of brain irradiation (3000 rad in 2 weeks) was compared to that of a high-dose course (5000 rad in 4 weeks) in a randomized RTOG clinical trial. Eighty percent of the 255 evaluable patients had lung primaries, 7% breast, and 13% other or unknown primaries. Patients with evidence of extra-cranial metastases, uncontrolled primaries, or Class IV Neurologic Function (NFIV) were excluded. Forty-one percent of NFII and 71 % of NFIV patients improved in neurologic function class. For NFII patients, a significantly greater improvement rate was obtained with the short course than with the long course. Otherwise there were no significant differences between the two regimens with respect to palliation of symptoms, improvement rate, median time to progression, cause of death, or median survival. We conclude that 3000 rad in two weeks is at least as effective as 5000 rad in four weeks in the palliation of brain metastases, even in this relatively favorable patient population.
319 citations
TL;DR: In this article, condensation of o-phenylenediamines with carboxylic acids and reaction of bifunctional alkyl halides with bifunctionsal nucleophiles are described.
303 citations
TL;DR: In adult mice, the epithelium of the oviduct, the endometrium, and the epididymis are the cells most reactive with the monoclonal antibody to SSEA-1; although some areas of the brain and kidney tubules are weakly positive.
298 citations
TL;DR: These studies indicate that adherence of C. albicans is enhanced by a surface component of germinated yeast, probably a surface protein that binds to the epithelial receptor, possibly a glycoprotein.
Abstract: Factors that may influence adherence of Candida albicans to exfoliated human vaginal and buccal epithelial cells were studied in vitro. Factors that enhanced germination enhanced adherence. Heat-killed, germinated Candida organisms demonstrated poorer adherence than viable Candida organisms and no better adherence than nonviable, ungerminated Candida organisms. The difference between adherence of C. albicans to buccal epithelial cells and that to vaginal epithelial cells was significant, as were differences among volunteers. Preincubation in fucose but not mannose, glucose or galactose solutions, preincubation of germinated yeast or of epithelial cells in chymotrypsin or trypsin, a culture supernatant of germinated yeast killed by ultraviolet light, or precoating of epithelial cells with lactobacilli each inhibited adherence. These studies indicate that adherence of C. albicans is enhanced by a surface component of germinated yeast, probably a surface protein that binds to the epithelial receptor, possibly a glycoprotein.
230 citations
TL;DR: Primary cultures of fibroblasts obtained from the papillary, reticular and subcutaneous layer of scleroderma skin were analyzed for protein synthesis by metabolic labeling and radioimmunoassays and showed increases in the production of total protein and collagen as well as of fibronectin and type III procollagen as compared to cells from unaffected individuals.
193 citations
TL;DR: It is reported that Plasmodium chabaudi adami (556KA) infection in B-cell-deficient mice results in an activation of a T- cell-dependent immune mechanism which terminates acute malaria in a similar way to that seen in immunologically intact mice.
Abstract: Immunity to malaria has a multicomponent basis which requires the participation of both T- and B-lymphocyte systems1. Previous studies have suggested that the T-lymphocyte system has an essential role in ‘re-infection immunity’ to malaria, but that B cells and/or their products are necessary for the host to survive acute infection and to clear the blood of parasites during chronic malaria2–4. Thus, B-cell-deficient mice and chickens died of fulminant malaria when infected with Plasmodium yoelii and Plasmodium gallinaceum, respectively2,3,5, but when their acute infections were controlled with subcurative chemotherapy, B-cell-deficient hosts developed chronic low-grade infections and resisted challenge with homologous parasites2,4. In contrast, athymic nude mice failed to control their endogenous P. yoelii infection after the termination of drug therapy unless they had been thymus grafted before initiation of acute infection3. We now report that Plasmodium chabaudi adami (556KA) infection in B-cell-deficient mice results in an activation of a T-cell-dependent immune mechanism which terminates acute malaria in a similar way to that seen in immunologically intact mice. Furthermore, these immunized B-cell-deficient mice were resistant to homologous challenge infection as well as infections initiated with Plasmodium vinckei, but not with P. yoelii and Plasmodium berghei.
174 citations
TL;DR: Membrane binding of ethanol, anesthetics, and hydrophobic molecules in brain synaptosomes and liver mitochondria from rats is conspicuously reduced after long-term consumption of ethanol.
Abstract: Membrane binding of ethanol, anesthetics, and hydrophobic molecules in brain synaptosomes and liver mitochondria from rats is conspicuously reduced after long-term consumption of ethanol. The membranes are resistant to structural disordering by both ethanol and halothane. Tolerance, cross-tolerance, and dependence in chronic alcoholics may in part result from membrane alterations that inhibit the binding of ethanol and other drugs.
173 citations
TL;DR: Two dimensional echocardiography appears to be the technique of choice in the detection, localization and differentiation of intraatrial masses.
Abstract: With two dimensional echocardiography, a left atrial mass was detected in 19 patients. Of these, 10 patients with rheumatic mitral stenosis had a left atrial thrombus. The distinctive two dimensional echocardiographic features of left atrial thrombus included a mass of irregular nonmobile laminated echoes within an enlarged atrial cavity, usually with a broad base of attachment to the posterior left atrial wall. Seven patients had a left atrial myxoma. Usually, the myxoma appeared as a mottled ovoid, sharply demarcated mobile mass attached to the interatrial septum. One patient had a right atrial angiosarcoma that appeared as a nonmobile mass extending from the inferior vena caval-right atrial junction into the right atrial cavity. One patient had a left atrial leiomyosarcoma producing a highly mobile mass attached to the lateral wall of the left atrium. M mode echocardiography detected six of the seven myxomas, one thrombus and neither of the other tumors. Thus, two dimensional echocardiography appears to be the technique of choice in the detection, localization and differentiation of intraatrial masses.
148 citations
TL;DR: For a class C of subsets of a set X, let V(C) be the smallest n such that no n-element set F@?X has all its subset of the form A@?
147 citations
TL;DR: In a series of experiments conducted in rats of different ages the degree of mismatch and the role of catch-up are compared and it is suggested that while the concept of mismatch is still acceptable the idea of a single central mechanism is not supported.
Abstract: To determine whether expansion of the splanchnic mesoderm of the area vasculosa is influenced by the entodermal substratum on which it occurs, entoderm was separated from a small area of splanchnic mesoderm. The splanchnic mesoderm then contracted and thickened, decreasing to 7% of its original area in 16 h. By then entoderm had reattached to most of it, and it expanded, reaching 11% of its original area by 24 h. It was concluded that attachment to entoderm may be required for expansion of the splanchnic mesoderm, but the small amount of expansion obtained made this conclusion tentative. For technical reasons subsequent investigation was done on mesodermal transplants, which attached to the host9s entoderm in 6 h, by which time they had contracted to 15% of their original area. They then expanded, reaching 30% by 16 h and 49% by 24 h. The onset of their expansion was also accompanied by the formation of connexions between their blood vessels and those of the host, and by the resumption of blood flow in them. To see whether their expansion was due to resumption of blood flow or to attachment to entoderm, other transplants were made in which the middle one-third was separated from the host9s entoderm by a piece of Millipore filter. This portion failed to expand although it became connected to the host9s blood vessels and flow of blood resumed in it, while the two lateral thirds, which regained attachment to entoderm, expanded. Transplants were also rotated so that their splanchnic mesoderm attached to ectoderm instead of entoderm. These transplants also formed connexions with the host9s vessels and blood flow resumed in them, but they expanded only slightly compared to non-rotated controls, in which the splanchnic mesoderm attached to entoderm. It was concluded that while flow of blood undoubtedly promotes splanchnic mesodermal expansion as others have shown, attachment of the splanchnic mesoderm to entoderm is also important, and without it the promotive effect of blood flow does not occur. Evidence was also obtained that attachment to entoderm maintains the thinness of the splanchnic mesoderm, and that a vascular growth stimulus may be produced by the unvascularized entoderm distal to the mesoderm.
TL;DR: Light and electron microscopic examination of the inner layers of the normal infant rat retina reveal naturally degenerating cell bodies in the ganglion cell layer, degenerating axons in the optic fiber layer, and degenerating processes in the inner plexiform layer.
TL;DR: A line of first order phase transitions terminating in a second-order phase transition separates the parameter space of the interacting boson model into a vibrator region [U(59) limit] and a rotor region [SU(3) and O(6) limits].
Abstract: A line of first order phase transitions terminating in a second-order phase transition separates the parameter space of the interacting boson model into a vibrator region [U(59) limit] and a rotor region [SU(3) and O(6) limits]. This first order phase transition line is surrounded by two spinodal lines demarking the limits of metastable nuclear isomers. No other islands of metastability exist in this parameter space.
TL;DR: The authors used longitudinal data from a suburban police department to assess whether increasing numbers of mentally ill individuals are coming to police attention in a state that has restrictive civil commitment laws and studied the outcomes of all incidents involving a mentally ill individual during a 5-month period.
Abstract: The authors used longitudinal data from a suburban police department to assess whether increasing numbers of mentally ill individuals are coming to police attention in a state that has restrictive civil commitment laws. To test the hypothesis that police would arrest disruptive but nondangerous individuals to expedite their removal from the community, the authors studied the outcomes of all incidents involving a mentally ill individual during a 5-month period. Mental-illness-related incidents coming to police attention increased 227.6% from 1975 to 1979. Although a 13% arrest rate was reported for nondangerous incidents, police officers invoked the penal code only as a last resort.
TL;DR: The human hepatoma cell line, Hep G2, provides a potential in vitro model for the study of regulation of human hepatic lipoprotein and apolipoprotein synthesis.
TL;DR: The results indicate that the neoplastic lymphocytes of B-CLL may proliferate and differentiate when appropriately stimulated in vitro, and that chromosomally abnormal clones are not uncommon.
TL;DR: The usefulness of two dimensional echocardiography in establishing the diagnosis of aortic dissection was evaluated and the intimal flap was detected in 12 of 15 patients with a dissection.
Abstract: The usefulness of two dimensional echocardiography in establishing the diagnosis of aortic dissection was evaluated. Forty-two patients were referred for study; 15 had a dissection and 27 did not. Two dimensional echocardiography detected the intimai flap in 12 of 15 patients with a dissection; the three false negative studies were in patients with a localized dissection. There was one false positive study in the 27 patients who did not have a dissection.
TL;DR: The distribution of carotid sinus nerve afferent and efferent fibers in the brain stem was examined in eight cats using horseradish peroxidase (HRP) neurohistochemistry and dense extraperikaryal labeling was seen within the nucleus of the tractus solitarius (nTS).
TL;DR: The central distribution of vagal preganglionic neurons has been examined using the retrograde transport of horseradish peroxidase (HRP) and it was found that different patterns exist for each visceral organ.
Abstract: The central distribution of vagal preganglionic neurons has been examined using the retrograde transport of horseradish peroxidase (HRP). In 27 adult cats, the entire vagus nerve was exposed to HRP. In 13 other cats we examined the brain stem following microinjections of HRP (10 microliter) into individual visceral organs - lung, heart and stomach. Comparison of individual cases led to the conclusion that different patterns exist for each visceral organ. The preganglionic (parasympathetic) innervation of the entire vagus nerve arises from the dorsal motor nucleus of the vagus (dmnX), nucleus ambiguus (nA), nucleus retroambigualis (nRA), nucleus dorso-medialis (ndm), spinal nucleus of the accessory (nspA) and from the reticular formation between the dmnX and nA. Axons arising from the nA do not traverse the medulla laterally; rather they are initially directed dorso-medially toward the dmnX where they bend at right angles and accompany axons of neurons in the dmnX. The motor nuclei innervating the lungs, heart and stomach are dmnX, the nA and nRA: the dmnX contributes fibers to the heart, lungs and stomach from a region of 10 mm of medulla rostrocaudally; the nA contributes efferents to the 3 viscera studied from the entire 6 mm contributing vagal efferents; the nRA contributes efferents to the stomach in addition to providing innervation to the larynx and trachea (see 19). The area postrema (ap) receives afferent input from the lungs, heart and stomach, as indicated by extraperikaryal grains of HRP reaction product resulting from transganglionically transported HRP (through the ganglion nodosum). Sensory terminal labeling in the various subnuclei of the nucleus of the tractus solitarius (nTS) was also examined and it was found that no specific region of the medulla is devoted to receiving input from any one visceral organ; rather the rostro-caudal extent of vagal afferent terminals in the medulla spans the entire length of the medulla. Differences between the central representation of different viscera seemed to lie within the organization of the nuclear subgroups of the nTS.
TL;DR: It is concluded that changes in cardiac output in normal subjects during upright exercise are related to augmentation of stroke volume and tachycardia, whereas in patients with coronary artery disease they are related mainly to tachy Cardia.
Abstract: Quantitative radionuclide angiography (with the first pass technique and a computerized multicrystal camera) was used to evaluate hemodynamic changes in three subject groups during symptom-limited upright exercise. The 12 normal subjects had significant increases in heart rate, stroke volume, left ventricular ejection fraction and cardiac output during exercise; changes in end-diastolic and end-systolic volumes were not significant. In the 24 patients with coronary artery disease there were significant increases in heart rate and cardiac output during exercise, but insignificant changes in end-diastolic, end-systolic and stroke volumes and ejection fraction. The change in diastolic volume in these patients was determined by the extent of coronary artery disease, propranolol therapy, end point of exercise and presence of collateral vessels. Furthermore, patients with previous myocardial infarction had a lower ejection fraction and higher end-diastolic and end-systolic volumes during exercise than those without myocardial infarction. In the 12 patients with chronic aortic regurgitation of moderate to severe degree, there was a decrease in the end-diastolic volume during exercise. This response was distinctly different from that of the normal subjects or the patients with coronary artery disease. All three groups had a significant decrease in pulmonary transit time during exercise. It is concluded that changes in cardiac output in normal subjects during upright exercise are related to augmentation of stroke volume and tachycardia, whereas in patients with coronary artery disease they are related mainly to tachycardia. Left ventricular dilatation during exercise occurred in some normal subjects and in patients with coronary artery disease but was not a consistent finding. However, a decrease in left ventricular end-diastolic volume is common in patients with aortic regurgitation. Such a decrease may be explained by a reduction in the regurgitant volume per beat caused by shortening of the diastolic filling period or a decrease in systemic vascular resistance, or both.
TL;DR: In this paper, a simple method for the derivation of the classical limit of the most general interacting boson model Hamiltonian as well as the Hamiltonians in the three limits of the interaction model is presented.
Abstract: We present a simple method for the derivation of the classical limit of the most general interacting boson model Hamiltonian as well as the Hamiltonians in the three limits of the interacting boson model. Also the problem of higher order terms is considered.[NUCLEAR STRUCTURE Classical limit of the interacting boson model.]
TL;DR: It is argued that oscillatory control provides a reliable, noise-resistant strategy for controlling secretion rate and the experimental results suggest that the potential oscillation may be driven by an oscillation in the intracellular concentrations of cyclic AMP and calcium.
Abstract: The effects of the hormone 5-hydroxytryptamine, its analogues and its antagonists on the electrical activity and secretion rate of isolated salivary glands of the blowfly Calliphora erythrocephala were investigated. The secretion rate increases linearly with the logarithm of hormone concentration between 10−9 and 10−8M. At >10−8M the transepithelial potential depolarizes and rapidly attains a new stable value. However, at intermediate hormone concentrations, the potential does not maintain a stable intermediate value but displays sustained oscillations. These oscillations are not an artifact resulting from periodic variations in hormone concentration. The frequency of the oscillations increases with hormone concentration and with the concentration of external calcium and hormone analogues. The frequency decreases following the addition of lanthanum to the perfusion medium.
The experimental results suggest that the potential oscillation may be driven by an oscillation in the intracellular concentrations of cyclic AMP and calcium. It is argued that oscillatory control provides a reliable, noise-resistant strategy for controlling secretion rate.
TL;DR: Individual long-chain fatty acid esters of retinol can be resolved by high-performance liquid chromatography using an octyl- or phenyl-substituted reverse-phase column and mixtures of acetonitrile with water as mobile phase to provide good resolution of biologically important retinyl esters including retinyl palmitate and retinyl oleate.
TL;DR: In this paper, the off-axis static and fatigue behavior of AS/3501-5A graphite/epoxy was studied in an effort to characterize the matrix/interface-controlled failure.
Abstract: Off-axis static and fatigue behavior of AS/3501-5A graphite/epoxy was studied in an effort to characterize the matrix/interface-controlled failure. Seven different off-axis angles were tested: 0, 10, 20, 30, 45, 60, and 90 deg. Initial (static) and post-fatigue residual strength were obtained together with S-N relationships. Fracture surfaces were examined through photomicrographs and stereo (three-dimensional) scanning electron microscope (SEM) photographs, in order to delineate failure modes, and the results of these inspections are discussed. The off-axis static strength, including scatter, was fully characterized by a polynomial and a nondimensional strength parameter. Essentially, no strength or modulus degradation was observed in the specimens surviving fatigue loading of 10 6 cycles regardless of the off-axis angle or fatigue stress level. When fatigue stress level is normalized with respect to static strength, all data seem to fall on the same S-N curve. Fatigue failure occurred without any warning or visible damage. Matrix failure characteristics vary with off-axis angle and appear in the form of serrations and axial and transverse cracks. Large scatter in life was observed at all off-axis angles; however, since the number of specimens employed in the present study is not sufficient to provide meaningful statistical S-N data, a more detailed investigation of the off-axis (and angle ply) behavior of graphite/epoxy composites is warranted.
TL;DR: It would appear that the anatomical plasticity of SP-containing fibers in the deafferented dorsal horn is due to the response of a particular system rather than to a generalized response of all systems which terminate there.
TL;DR: In this article, a comparison between simple micellar systems and micro-emulsions is made, and both the similarities and unique differences between micelles and micromulsions are discussed.
TL;DR: The asymptotic detection performance of the locally optimum detector under non-Gaussian conditions is derived and compared with that for the corresponding detector optimized for operations in Gaussian noise.
Abstract: A locally optimum detector structure is derived for the detection of weak signals in non-Gaussian environments. Optimum performance is obtained by employing a zero-memory nonlinearity prior to the matched filter that would be optimum for detecting the signal were the noise Gaussian. The asymptotic detection performance of the locally optimum detector under non-Gaussian conditions is derived and compared with that for the corresponding detector optimized for operations in Gaussian noise. Numerical results for the asymptotic detection performance are shown for signal detection in noise environments of practical interest.
TL;DR: This paper demonstrates how the same arguments can be applied to biochemical control networks and shows that the conversion of an analogue demand signal to an oscillation is stable against corruption by noise in the input and even against Corruption by certain internal chaotic motions.
TL;DR: The results suggest that the synthesis of one or more of the enzymes responsible for aflatoxin formation is regulated by the availability of specific readily-metabolizable carbon sources.
Abstract: The ability of various compounds to induce aflatoxin biosynthesis by Aspergillus parasiticus was investigated by initially culturing the organism in a peptone basal medium that does not support aflatoxin production, and then transferring the organism to a replacement medium containing the test compound. Ribose, xylose, glucose, fructose, sorbose, mannose, galactose, maltose, sucrose, raffinose, and glycerol induced aflatoxin production. This induction of aflatoxin production was blocked when cycloheximide was incorporated into the replacement medium. Aflatoxin biosynthesis was not induced by lactose, lactic acid, sodium pyruvate, oleic acid, citric acid, sodium acetate, α-methyl-D-glucoside, 3-0-methyl-D-glucoside, cAMP, or cGMP. The results suggest that the synthesis of one or more of the enzymes responsible for aflatoxin formation is regulated by the availability of specific readily-metabolizable carbon sources.