Showing papers by "Drexel University published in 1976"

Stability of microstructure in metallic systems

Abstract: Preface Preface to Second Edition 1. The general problem of the stability of microstructure 2. Structural instability due to chemical free energy 3. Highly metastable alloys 4. Instability due to strain energy 5. Microstructural instability due to interfaces 6. Other causes of microstructural instability Index.

Mechanism by Which Psychotropic Drugs Inhibit Adenosine Cyclic 3',5'-Monophosphate Phosphodiesterase of Brain

Abstract: Bovine brain contains several molecular forms of adenosine cyclic 39,59-monophosphate phosphodiesterase. The activity of one of these forms is increased several fold by an endogenous protein activator. Chlorpromazine, a potent phenothiazine tranquilizer, specifically inhibits the activation of a partially purified phosphodiesterase prepared from bovine brain at concentrations which do not inhibit the enzyme in the absence of activator. Ethylene glycol bis(β-aminoethyl ether)-N,N9-tetraacetic acid (EGTA), a calcium chelator, also specifically inhibits the activation of phosphodiesterase. However, the mechanisms by which EGTA and chlorpromazine act are different. EGTA produces its effect by chelating calcium, a required cofactor for phosphodiesterase activation; the EGTA-induced inhibition can be overcome by increasing the calcium concentration but not by increasing the concentration of activator. In contrast, chlorpromazine inhibits the activation of phosphodiesterase by interfering with the phosphodiesterase-activator interaction; the chlorpromazine-induced inhibition can be overcome by increasing the concentration of activator but not by increasing the concentration of calcium. Several other psychotropic drugs also inhibit the activation of phosphodiesterase of bovine brain. The antipsychotic agents trifluoperazine, thioridazine, benperidol, pimozide, and chlorprothixene are all potent, selective inhibitors of the activation of phosphodiesterase. The antianxiety agents medazepam and chlordiazepoxide and the antidepressants amitriptyline, protriptyline, and desipramine also selectively inhibit the activation of phosphodiesterase but are significantly less potent than the antipsychotics. Phenothiazines with relatively weak antipsychotic actions, chlorpromazine sulfoxide and promethazine, are less selective and less potent inhibitors than the antipsychotic phenothiazine derivatives. Other agents having central pharmacological actions, such as pentobarbital, pipradrol, D-lysergic acid diethylamide, pentylenetetrazol, morphine, and amphetamine, are poor inhibitors of either the activated or unactivated phoshodiesterase. These findings suggest that (a) the mechanism by which the phenothiazines inhibit the activation of phosphodiesterase involves competition with the endogenous protein activator of phosphodiesterase, and (b) selective inhibition of the activation of phosphodiesterase is a property common to agents which are effective in certain forms of psychiatric illnesses rather than to either general central nervous system depressants or stimulants.

Regeneration of retinal axons into the goldfish optic tectum.

Abstract: The growth of regenerating retinal axons into the central portion of the optic tectum of adult goldfish was examined with the light and electron microscopes. Optic tracts were cut and, two days to five months later, the animals were perfused and the tecta prepared for microscopy. Regenerating axons first reached central regions of the tectum seven to ten days postoperatively. Regenerating axons appear in very large numbers and travel in fascicles in the stratum opticum (SO) and in the adjacent neuropil, the stratum fibrosum et griseum superficiale (SFGS). In the SO, the fascicles are bordered by glial cells and degenerating debris. Within the SFGS, however, the fascicles do not seem to be similarly associated with glial cells and degenerating debris. The youngest regenerating axons are very slender processes, containing microtubules but few or no neurofilaments or dense granular material. By 10 to 14 days postoperatively, neurofilaments can be seen and, in addition, large numbers of vesicles with dense cores appear. The vesicles with dense cores increase in numbers until about 28 days postoperatively and then become quite rare. That vesicles with dense cores were seen in regenerating axons in both SO and SFGS during the period of growth into the tectum but were not seen in axon terminals at any time, suggests that they may be concerned with axon elongation. During the period one month to five months postoperatively, the regenerating axons gradually increase in diameter but do not reach preoperative sizes, suggesting that the regenerative changes may still be occurring. Remyelination is delayed and proceeds slowly. Many axons remain unmyelinated for as long as five months postoperatively.

Unrelated animal viruses share receptors.

Abstract: THE specific receptors for several non-enveloped viruses are present on cells in only limited numbers (1 × 104–10 × 104), and can therefore be saturated with excess virus1–5. An excess of inactivated poliovirus type 1 inhibits the attachment of infectious poliovirus of all 3 serotypes, but not the attachment of other viruses, including B Coxsackie viruses6. Most of the B Coxsackie viruses probably share the same receptor7, but Coxsackie viruses B1 and B3 do not compete for the poliovirus receptor1. Adenovirus 2 and 5 also appear to share the same receptor, since their attachment to host cells is blocked by an excess of the adenovirus type 2 fibre protein, which seems to be the receptor-recognising portion of the virus particle2. A number of other adenoviruses may also belong to the same receptor family since soluble antigens block their attachment to erythrocytes8. We here report results which permit the construction of a ‘receptor map’ for a number of non-enveloped viruses.

A Time-Dependent Lateral Boundary Scheme for Limited-Area Primitive Equation Models

Abstract: Before high-resolution numerical models can be of use operationally, they must be restricted to a limited domain, thus necessitating lateral boundary conditions which allow the changes outside the limited domain to influence the results while not contaminating the forecast with spurious boundary-reflected energy. Such a set of time-dependent lateral boundary conditions are presented in this paper. This boundary condition set is investigated using the linear analytic and finite-difference advection equations, the non-linear finite-difference shallow-water equations, and the hydrostatic primitive equations. The results illustrate how the boundary condition transforms long- and medium-length interior advective and gravity waves into short waves which can then be removed by a low pass filter, thereby giving the appearance that the exiting wave simply passed through the boundary. The results also indicate that large-scale advective and gravity waves enter the forecast domain with little degradation. T...

Release of Potential Instability: Part I. A Sequential Plume Model within a Hydrostatic Primitive Equation Model

Abstract: The release of potential instability by large-scale lifting and the subsequent interaction of cumulus convection and the hydrostatic mesoscale flow in a most complex scale-interaction process. This process is an essential part of tropical weather but it is also important in extratropical cyclones through the formation of mesoscale rainbands that contribute much of the precipitation. The purpose of this paper is to qualitatively and quantitatively clarify the potential instability release process within a framework that will permit calculation of convective/mesoscale interactions. The approach is to use an extension of the Lagrangian form of the one-dimensional cumulus model to provide values of convective-scale changes to a hydrostatic primitive equation model. This cumulus sub-routine locates the base of the convection, computes the cumulus plume that will build, accounts for the environmental subsidence, and mixes the subsided environment with the cumulus plume after rainout. These plumes build...

Heroin addiction: Theory, research, and treatment

Abstract: Examining the advances made in the last 10 years with heroin addiction, this book covers non-pharmacological interventions including cognitive behaviour therapy, theraputic communities, and family therapy. HIV and AIDS relating to hyperdermic needle use are covered, as is addicted women.

Membrane-Bound γ-Glutamyl Transpeptidase

Abstract: γ-Glutamyl transpeptidase is a membrane-bound enzyme that catalyzes the transfer of the γ-glutamyl moiety of glutathione (and of other γ-glutamyl compounds) to amino acid (and peptide) acceptors as indicated in reaction (1): $$ glutathione + a\min o\,acid \to \gamma - glutamyl\,a\min o\,acid + cysteinyl\,glycine $$ (1) This reaction is the first step in a quantitatively significant pathway of glutathione metabolism, and it has been postulated that this or analogous reactions are involved in amino acid transport. Thus, γ-glutamyl transpeptidase mediates the translocation of the amino acid across the cell membrane by interacting with both extracellular amino acid and intracellular glutathione (or other compounds that contain the γ-glutamyl carrier); according to this idea, the amino acid enters the cell as a γ-glutamyl amino acid.

Configuration at C-24 of 24-methyl and 24-ethylcholesterol in tracheophytes

Abstract: 24-Ethylcholesterol was shown by proton magnetic resonance spectroscopy to have only the α-configuration in a series of tracheophytes ranging through the evolutionary hierarchy from ferns through gymnosperms and primitive angiosperms to climax angiosperms. 24-Methylcholesterol, however, was consistently an epimeric mixture, with the 24α-epimer present in about twice the concentration of the 24β-epimer. 24-Methylcholesterol was always present in smaller amount than the 24-ethylcholesterol.

Early eye removal produces excessive bilateral branching in the rat: application of cobalt filling method

Abstract: When one eye of a rat is removed at birth, axons from the remaining eye form an excess of branches which are directed to both sides of the brain. This finding, which is based on a novel application of cobalt tracing methods, provides an explanation for previous reports of expanded uncrossed projections after early eye removal.

Acculturation and psychopathology among puerto rican women in mainland united states

Abstract: This study explores relationships between the stress of acculturation and the existence of psychopathology among 72 Puerto Rican women in mainland United States. Significant correlations were found between level of acculturation and education and both personality adjustment and psychopathology. Implications for Puerto Rican family structure are discussed, and suggestions for further research are offered.

Differences in the attenuation of ultrasound by normal, benign, and malignant breast tissue.

Abstract: In quantitative measurements of the attenuation of ultrasound in 18 samples of variously normal, benign, and malignant breast tissue, we found significantly different ranges of attenuation. As observed in previous in vivo studies, with the exception of medullary carcinoma, malignant tissue produces the most attentuation of ultrasound in the frequency range of 1.5 to 3.0 MHz we employed. The apparatus, measurement method, results, and the possible causes of the differences in attenuation are presented.

Connective tissue synthesis by cultured scleroderma fibroblasts. I. In vitro collagen synthesis by normal and scleroderma dermal fibroblasts

Abstract: The authors have been unable to demonstrate an increase in collagen synthesis by fibroblasts isolated from sclerodermatous skin. In order to elucidate this problem further, scleroderma fibroblasts were biopsied from upper dermis, from lower (including subcutaneous) dermis, and from adjacent clinically noninvolved skin. All cell lines failed to show a significant increase in collagen synthesis when they were compared to control fibroblast lines. One difference among them was that fibroblasts from involved areas showed a rate of collagen synthesis equal to or less than cells isolated from adjacent clinically noninvolved sites.

Image modulation in corona discharge photography

Abstract: Photographic images obtained by the Kirlian technique are principally a record of corona activity during an exposure interval. Most of the variations in the images of the corona of a living subject who is in contact with the photographic film can be accounted for by the presence of moisture on or within the subject's surface. During exposure, moisture is transferred from the subject to the emulsion surface of the photographic film and causes an alteration of the electric charge pattern on the film, hence the electric field at the surface of the subject. As a result, large variations in the density of corona images, corona streamer trajectories, and image coloration can be brought about. The radial extent of corona images--that is, the range of corona streamers--is an inverse function of the resistance in the circuit formed by the high-voltage supply, the subject, and the film-electrode configuration. This is because the voltage at which corona is initiated is dependent on the rate of rise of the voltage impressed between the subject and the electrode, and the rate of rise is governed by the applied voltage waveform and the voltage drop across the resistance. The range of streamers is proportional to the corona onset voltage. However, we have not seen any influence of large changes in skin resistance on streamer range. Presumably, this is due to the shunting effect of skin capacitance. In general, the photographic response to moisture suggests that corona discharge photography may be useful in the detection and quantification of moisture in animate and inanimate specimens through the orderly modulation of the image due to various levels of moisture.

Schottky Barrier Betavoltaic Battery

Abstract: A new nuclear betavotaic battety is described. It uses a Schottky barrier in place of the more standard p-n junction diode, along with 147Pm metal film rather than Pm2O3 oxide as in the commercially available Betacel. Design details of the battery including measurement of absorption, conversion efficiency, thickness etc. as functions of & resistivity and other cell parameters are described. A prototype design is discussed and its performance assessed.

Ultrastructural changes of the canine gastric mucosa after topical application of graded concentrations of ethanol.

Abstract: Changes in the fine structure of the gastric mucosa following exposure to graded concentrations of ethanol were studied in dogs. 300 ml of 12.5, 20, and 40%, vol/vol, were instilled intragastrically for 30 min. Mucosa from the midbody and midantrum along the greater curvature was examined by light and electron microscopy. Ethanol produced a gradation of changes in the surface epithelial cells and in the lamina propria without affecting the parietal cells and chief cells. 12.5% ethanol produced widened and irregular intercellular spaces while 20 and 40% disrupted the apical cell membrane with concomitant exudation of mucin into the gastric lumen. These changes were more severe after 40% ethanol. The tight junction between cells remained intact following exposure to the lower concentrations of ethanol, but focal separation of cell junctions was observed in severely damaged areas. Quantitation of protein, sodium, and potassium concentrations in the gastric contents revealed marked increases following exposure to ethanol which correlated with the concentration. These studies provide additional morphological data on the relationship between structural changes and functional abnormalities induced by agents which break the gastric mucosal barrier.

Atmospheric temperature profiles from lidar measurements of rotational Raman and elastic scattering

Abstract: Criteria for optimizing system parameters in the lidar measurement of atmospheric temperature profiles from simultaneous Raman and elastic returns by use of a three-channel system are discussed and summarized. It is shown that the filter constraints of earlier techniques are removed thereby eliminating the need for the high rejection capability of spectrometers in this type of measurement. Also, SNR is improved, and a greater freedom in the choice of optimum Raman filters is demonstrated.

Emotional and social real-life problem-solving thinking in adolescent and adult psychiatric patients.

Abstract: The ability of adult and adolescent psychiatric patients to solve emotional problems such as anxiety and depression as well as problems that arise within the social sphere was examined, as was the question of whether the abilities to solve problems in the emotional and social spheres are related. With IQ partialled out, patients and controls did not differ on emotional problem-solving ability, but did differ on social problem-solving ability. Emotional problem-solving ability was found to be related to intelligence, while social problem-solving ability was not. Emotional problem-solving may require more abstract ability than social problem-solving, and normals may need only social problem-solving for adjustment.

Nonsterilizing immunity in avian malaria: an antibody-independent phenomenon.

Abstract: SummaryAgammaglobulinemic chickens died with fulminating parasitemias following infection with P. gallinaceum. When rescued from otherwise fatal infection by means of chloroquine therapy, B-cell deficient chickens resisted challenge infection with the same parasite. The data suggest that nonsterilizing immunity to malaria in chickens is B-cell independent.We wish to thank Drs. Burton J. Landau and E. J. L. Soulsby for their helpful criticism in the preparation of this manuscript. This work was aided in part by US-PHA Grant AI No. 12710-01.

Regulation of mammalian protein synthesis in vivo. Protein synthesis in rat liver and kidney after the administration of sublethal doses of cyclohyximide.

Abstract: Protein synthesis in vivo was studied at various times after the administration of sublethal doses of cycloheximide to rats. Cycloheximide caused an inhibition, followed by a dose-and time-dependent stimulation, of incorportation of labelled precursor into proteins of the liver and kidney. The stimulation of protein synthesis at 24h was not due to a change of precursor pool or the specific radioactivity of the precursor used. During the stimulatory period, leucine incorporation into various cellular protein fractions varied; incorporation into total nuclear protein was the most affected.