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Showing papers by "Drexel University published in 1983"


Journal ArticleDOI
K. Subramanyam1
TL;DR: Several types of collaboration have been identified, and earlier research on collaboration has been reviewed, andibliometric methods offer a convenient and non-reactive tool for studying collaboration in research.
Abstract: Scientific research is becoming an increasingly collaborative endeavour. The nature and magnitude of collaboration vary from one discipline to another, and depend upon such factors as the nature of...

847 citations


Journal ArticleDOI
TL;DR: In this article, the authors considered the plane elasticity problem for a nonhomogeneous medium containing a crack and derived the integral equation having the derivative of the crack surface displacement as the density function.
Abstract: The plane elasticity problem for a nonhomogeneous medium containing a crack is considered. It is assumed that the Poisson's ratio of the medium is constant and the Young's modulus E varies exponentially with the coordinate parallel to the crack. First the half plane problem is formulated and the solution is given for arbitrary tractions along the boundary. Then the integral equation for the crack problem is derived. It is shown that the integral equation having the derivative of the crack surface displacement as the density function has a simple Cauchy type kernel. Hence, its solution and the stresses around the crack tips have the conventional square root singularity. The solution is given for various loading conditions. The results show that the effect of the Poisson's ratio and consequently that of the thickness constraint on the stress intensity factors are rather negligible.

711 citations


Journal ArticleDOI
Joan McCord1
TL;DR: Maternal self-confidence and education appeared to decrease vulnerability to the adverse impact of child abuse, and rates of alcoholism, divorce, and occupational success were similar among the four groups.

326 citations


Journal ArticleDOI
15 Aug 1983-Cancer
TL;DR: Evaluated Adriamycin with and without dimethyl‐triazeno‐imid‐azole‐carboxamide in the treatment of Stage III or IV and recurrent sarcomas of the uterus and there was no survival advantage.
Abstract: Various drug combinations including Adriamycin have been tested in soft tissue sarcomas, but optimal treatment remains unclear. We have evaluated Adriamycin with and without dimethyl-triazeno-imidazole-carboxamide (DTIC) in the treatment of Stage III or IV and recurrent sarcomas of the uterus. Two hundred and forty cases of these rare tumors were evaluable. Of 146 evaluable patients with measurable disease, 13/80 (16.3%) of Adriamycin-treated patients and 16/66 (24.2%) of patients receiving the combination showed an objective response (P greater than 0.05). Lung metastases responded more frequently (P equal to 0.04) to combination therapy, but there was no survival advantage. For patients with nonmeasurable disease the progression-free interval was similar (10.0 months for Adriamycin and 8.0 months for the combination). Leiomyosarcomas had a significantly longer survival than other cell types (12.1 versus 6.0 months, P less than 0.001) but there was no advantage for either regimen. There was a suggestion that heterologous mixed mesodermal sarcomas were more responsive to the combination (27.3 versus 8.7%). The addition of DTIC produced significantly more hematologic and gastrointestinal toxicity. Other Adriamycin combinations should be evaluated in uterine sarcomas.

322 citations


Journal ArticleDOI
TL;DR: The effects on neuron number of varying the diameter of the neuronal nucleus, the size of the smallest resolvable profile, and the thickness of the section were determined using computer simulations of neuron populations.
Abstract: Published values for the number of neurons in the superior cervical ganglion of the adult rat range from 13 000 to 45 000. These studies have employed different methods for determining what unit to count (cell body, nucleus, nucleolus), how many sections to count, and how to correct the raw counts for split particles and for profiles that are too small to resolve. The purpose of this study was to examine the extent to which these parameters may influence the calculated value for the total number of neurons, using computer simulations of neuron populations. These simulations permitted us to determine the effects on neuron number of varying the diameter of the neuronal nucleus, the size of the smallest resolvable profile, and the thickness of the section. The data from the simulations were used to test the validity of several methods that are in common use for correction of neuron counts. Our results indicate that most of the methods that are in routine use are unsatisfactory. We propose the use of either one of two methods that consistently result in highly accurate estimates of neuron numbers. These are: (1) a modification of the method proposed by Hendry (1976), using computer analysis; or (2) a modification of the method proposed by Abercrombie (1946), which does not require the use of a computer.

212 citations


Journal ArticleDOI
TL;DR: Thermally derived ejection fraction determinations can be helpful in hemodynamic monitoring of critically ill patients because of its low cost, ease of use, and accuracy.

206 citations


Journal ArticleDOI
TL;DR: The finding of thrombolysis in several patients with nontransmural MI and UA suggests that intracoronary thrombus formation plays a pathogenetic role in some patients with these ischemic syndromes.
Abstract: Although intracoronary thrombus formation plays a major role in acute transmural myocardial infarction (MI), its occurrence in unstable angina (UA) and nontransmural MI has not clearly been established. To determine whether intracoronary thrombus does occur in these syndromes, coronary arteriography was performed before, during, and after intracoronary nitroglycerin and streptokinase infusion in 17 patients. None of the 8 patients with nontransmural MI and 1 of the 9 patients with UA responded to intracoronary nitroglycerin. Seven of 8 patients with nontransmural MI and 4 of 9 patients with UA responded to streptokinase infusion with opening of an occluded vessel, an increase in stenotic diameter, dissolution of an intracoronary filling defect, or a combination of these. Serial opening and closing of ischemia-related vessels occurred spontaneously and in response to streptokinase in some patients in whom thrombolysis was demonstrated. Evidence of thrombolysis was not seen in any patient studied longer than 1 week from the onset of the rest pain syndrome. The finding of thrombolysis in several patients with nontransmural MI and UA suggests that intracoronary thrombus formation plays a pathogenetic role in some patients with these ischemic syndromes.

182 citations


Journal ArticleDOI
TL;DR: In this article, the authors identify some of these recurrent difficulties and recommend alternatives where possible, and discuss three general topics: the measures employed, the assessment format and conceptual issues which bear on assessment.

174 citations


Journal ArticleDOI
TL;DR: Results suggests that SR plays an importnat role in pathogenesis of MH, and dantrolene was shown to inhibit the halothane‐induced calcium release.

160 citations


Journal ArticleDOI
TL;DR: The effect of lipid peroxidation on membrane fluidity was examined in sonicated soybean phospholipid vesicles and indicates that lipid per oxidation leads to an alteration of the transbilayer fluidity gradient.

159 citations



Journal ArticleDOI
TL;DR: Findings indicate that the synthesis of entactin and laminin is asynchronous in the early stages of mouse embryonic development but becomes synchronized in the postimplantational stages of development.

Journal ArticleDOI
TL;DR: It is concluded that neuron death is an important aspect of early postnatal development in the rat SCG.
Abstract: Counts of neurons of the rat superior cervical ganglion (SCG) were made at two days before birth and at several postnatal ages. There is a significant decline in the number of apparently normal neurons over the first postnatal week, with the number falling from 39 500 at 3 days to 26 500 at 7 days. Cell numbers then remained constant up to day 60 when the number of neurons was 27 500. The incidence of degenerating neurons, identified by light and electron microscopy, was correlated temporally with the loss of normal neurons. The early manifestations of the neuron degeneration were chromatin clumping and the presence of free monoribosomes. Later stages were characterized by increased chromatin clumping, dense aggregations of monoribosomes, numerous intracytoplasmic vacuoles, and only short segments of rough endoplasmic reticulum. The ultrastructure of the majority of these dying neurons is similar to the ‘nuclear’ types of degeneration described by Pilar & Landmesser (1976) and Chu-Wang & Oppenheim (1978). Based on the presence of degenerating neurons coincident with the reduction in neuron numbers, we conclude that neuron death is an important aspect of early postnatal development in the rat SCG.

Journal ArticleDOI
TL;DR: Effective infection control programs in hospitals appear to reduce the incidence of nosocomial pulmonary infection, and implementation of these programs deserves serious consideration in all hospitals.
Abstract: Nosocomial respiratory tract infections are major causes of excessive morbidity and mortality in US hospitals, affecting an estimated five to ten of every 1,000 patients. Patients with serious underlying diseases have an especially high risk of acquiring these infections, and that risk is magnified by exposure to respiratory therapy. Until recently, contaminated respiratory care devices were a major cause of infection, but procedures for the management of these devices have decreased their role substantially. Now, aspiration of oropharyngeal flora appears to be responsible for most cases of bacterial respiratory infections. Therefore, techniques to alter the flora of the oropharynx and to diminish the risk of aspiration are important priorities for infection control. Exposure to intensive care units (ICUs) is also a major risk factor for nosocomial pulmonary infection, and person-to-person spread of microorganisms within ICUs seems to be responsible for some of these infections. Increasing numbers of pulmonary infections are being caused by newly identified or previously uncommon pathogens, and this shift requires that traditional control techniques be reevaluated to assure that they remain relevant. Few new techniques have been developed recently to alter host susceptibility, prevent acquisition of virulent pathogens, or eradicate infectious organisms from their sources, but effective infection control programs in hospitals appear to reduce the incidence of nosocomial pulmonary infection, and implementation of these programs deserves serious consideration in all hospitals.

Journal ArticleDOI
TL;DR: It is demonstrated that sparing of tactile placing occurs after neonatal but not adult spinal cord damage and that the spared tactile placing of one limb depends on the corresponding (contralateral) sensorimotor cortex and that only the latest developing pathways displayed anatomical sparing.

Proceedings ArticleDOI
P.R. Kalata1
01 Dec 1983
TL;DR: The derived Tracking Index, a generalized parameter proportional to the ratio of the position uncertainty due to the target maneuverability to thatDue to the sensor measurement, is found to have a fundamental role in the optimal solution of the stochastic regulation tracking problem.
Abstract: Applying optimal filtering theory to the target tracking problem, the derived Tracking Index, a generalized parameter proportional to the ratio of the position uncertainty due to the target maneuverability to that due to the sensor measurement, is found to have a fundamental role in the optimal solution of the stochastic regulation tracking problem. Depending on the order of the tracking model, the Tracking Index solution yields a closed form, consistent set of generalized tracking gains, relationships, and performances.

Journal ArticleDOI
TL;DR: In this article, the results of an experimental investigation of the ozonation of phenol in a semi-batch reactor were presented, in which mass-transfer kinetics of ozone into solution and the reaction between molecular ozone and phenol were considered separately.

Journal ArticleDOI
TL;DR: The mechanism of blood-flow reduction to atelectatic lung is therefore hypoxic pulmonary vasoconstriction, determined by the PVO2.
Abstract: The influence of mixed venous oxygen tension (PVO2) on blood flow to the atelectatic left lung was studied at normal and reduced cardiac outputs (CO) using extracorporeal veno-venous bypass in six pentobarbital anesthetized, mechanically ventilated dogs. Aortic and left pulmonary artery flows; airwa

Journal ArticleDOI
TL;DR: In this paper, a formal approach is presented of ordering the time scales of the dominant fluxes of material in an estuary and then accordingly choosing the spatial and temporal resolution of the sampling program.
Abstract: Abstruct A formal approach is presented of ordering the time scales of the dominant fluxes of material in an estuary and then accordingly choosing the spatial and temporal resolution of the sampling program. In this way bounds can be derived for the internal turnover times, boundary exchange rates, and import or export fluxes of a particular substance purely from measurements of the standing stock values in the estuary water. Application of this methodology to an experiment in the Duplin River, Georgia, showed that if the effects of the water motion and mixing are extracted from the variation of a biological component, then the variability of the residual can be successfully interpreted. For a typical summer condition it was shown that ammonium was cycled rapidly within the marsh water, its distribution was very patchy, and only its decomposition products left the marsh; that the refractory dissolved organic carbon (DOC) component was steadily exported by longitudinal mixing while labile DOC was rapidly recycled in the water; that silicate was produced in large amounts in the marsh and exported by longitudinal mixing; that particulate organic carbon (POC) concentrations were almost completely determined by the turbulence intensity in the water; and that compared to this internal cycling, export was of minor significance.


Journal ArticleDOI
TL;DR: A model which quantified the degree of epileptiform activity and correlated it with changes in cardiovascular function and autonomic cardiac neural discharge found an imbalance within and between sympathetic and parasympathetic cardiac neural discharges.

Journal ArticleDOI
TL;DR: In this paper, an acetate-enriched methanogenic culture was assayed for nutritional stimulation by nickel in combination with other inorganic and organic nutrients, i.e. iron, cobalt, yeast extract, riboflavin and vitamin B12.

Journal ArticleDOI
TL;DR: In this article, a procedure for the preparation of various bidentate and linear tetradentate benzimidazoles and benzothiazoles incorporating units such as pyridyl and thioether was described.

Journal ArticleDOI
TL;DR: In this paper, the acidity of dry air south of a warm front was measured before it ascended producing a large area of warm frontal precipitation, and the chemical compositions of the dry air and precipitation at cloud base suggest a significant production of both sulfuric and nitric acids in the cloud.

Journal ArticleDOI
TL;DR: In this paper, a longitudinal field survey and a laboratory simulation were designed to test the effects of realistic expectations and value attainment on job-related attitudes and perceptions, finding that value attainment (the match between job values and job experiences) accounted for considerably more variance in facet satisfaction than did realistic expectations.

Journal ArticleDOI
TL;DR: A process for preparing Al-alloy castings containing dispersions of zircon particles is described in this article, where composites were prepared by stirring Zircon particle (40 to 200 µm size) in commercially pure Al (99.5 pct)* and Al-11.8 pct Si melts and subsequently casting these melts in permanent molds.
Abstract: A process for preparing Al-alloy castings containing dispersions of zircon particles is described. Composites were prepared by stirring zircon particles (40 to 200 µm size) in commercially pure Al (99.5 pct)* and Al-11.8 pct Si melts and subsequently casting these melts in permanent molds. It was found to be necessary to alloy the above two melts with 3 pct Mg to disperse substantial amounts of zircon particles (25 to 30 pct). Further, it was possible to disperse up to 60 wt pct zircon by adding up to 5 pct Mg; however, the melts containing above 30 wt pct zircon showed insufficient fluidity for gravity diecasting and had to be pressure diecast. Microstructural studies of cast composites indicated the presence of a reaction zone at the periphery of zircon particles, and electron probe microanalysis showed concentrations of Mg and Si at the particle-matrix interface. Hardness, abrasive wear resistance, elastic modulus, 0.2 pct proof stress, and tensile strength of cast Al-3 pct Mg alloy were found to improve with the dispersions of zircon particles. Scanning electron micrographs of abraded and fractured surfaces did not show any evidence of particle pull-outs or voids at the particle matrix interface, indicating strong continuous bonding.

Journal ArticleDOI
TL;DR: The connectivity of the corpus callosum in visual cortical areas 17 and 18 was studied in normal cats, in cats reared with unilateral convergent or divergent surgically-induced strabismus, and in a Siamese cat to imply that the abnormal callosal connectivity ofSiamese cats is not a simple result of strabistismus.

Journal ArticleDOI
TL;DR: In this article, the authors propose a solution structurale des deux complexes [Cu(BBES) (MeOH) (OH 2 )] (ClO 4 ) 2 and [cu(BBes) (acoc)] PF 6 •H 2 O•EtOH, BBES=bis-(N-methylbenzimidazolyl-2)-1,5 oxo-3 pentane.
Abstract: Resolution structurale des deux complexes [Cu(BBES) (MeOH) (OH 2 )] (ClO 4 ) 2 et [Cu(BBES) (acoc)] PF 6 •H 2 O•EtOH, BBES=bis-(N-methylbenzimidazolyl-2)-1,5 oxo-3 pentane. Spectres RPE montrant que les complexes gardent leurs structures deformees en solution

Journal ArticleDOI
TL;DR: Two aspects of this study support the hypothesis that later developing motor patterns will have a greater chance for survival and subsequent development than those which are present at birth, but the hypothesis is not supported when the long-term effect of spinal cord lesions on the maturation of motor behavior is considered.

Journal ArticleDOI
TL;DR: Results indicate a correlation between the activation of protein synthesis in eggs and the association of polyribosomes with the CSK, and several lines of evidence suggest that mRNA is a component of theCSK of both eggs and embryos.