Showing papers by "Istanbul University published in 1981"
TL;DR: The Karakaya marginal sea was already closed by earliest Jurassic times because early Jurassic sediments unconformably overlie its deformed lithologies as discussed by the authors, and it was closed by collision of the Bitlis-Poturge fragment with Arabia.
2,899 citations
TL;DR: The most promising approach to preventing or reducing the incidence of midline fracture of dentures appears to be reinforcement in the anterior part of the palate of the denture.
Abstract: The causes of midline fracture of dentures are discussed in both clinical and materials science terms. Many midline fractures can be avoided by the application of established prosthodontic principles in constructing and maintaining dentures. Improvements in the resins and processing techniques can also reduce the incidence of midline fracture. The most promising approach to preventing or reducing the incidence of this problem appears to be reinforcement in the anterior part of the palate of the denture.
188 citations
TL;DR: Two new α-dioximes, 1,4-diphenyl-2,3-bis(hydroxyimino)-piperazine, DBPH2, and bis(α-mercaptopyridyl)glyoxime, and their stereoisomers have been isolated as mentioned in this paper.
Abstract: Two new α-dioximes, 1,4-diphenyl-2,3-bis(hydroxyimino)-piperazine, DBPH2, and bis(α-mercaptopyridyl)glyoxime, BMGH2, and their stereoisomers have been isolated Their complexes with various transition metal ions have been synthesized The transformation of the amphi-DBPNi(II) complex to anti-form has been investigated The structures of all isolated compounds were proposed on the basis of analyses, ir and uv-visible data
74 citations
TL;DR: In this paper, the authors considered the case where the boundary extends to infinity in an infinitely extended angular space and an edge that is parallel to the cylinder axis is assumed to be a perfect absorber for angularly propagating waves.
Abstract: When a cylindrically curved perfectly conducting concave surface is terminated abruptly, an incident whispering gallery (WG) mode undergoes diffraction. This phenomenon is studied here for the canonical problem of a thin boundary and an edge that is parallel to the cylinder axis. To confine attention to diffraction by a single edge, it is assumed that the boundary extends to infinity in an infinitely extended angular space that is equivalent to placing along some radial plane intersecting the boundary a perfect absorber for angularly propagating waves. The problem can then be phrased as a functional equation problem of the Hilbert type which is solved exactly. An asymptotic approximation in the high frequency limit ka \gg 1 , where k is the wavelength and a the radius of curvature, is obtained in explicit form and phrased so as to exhibit the diffraction coefficient for edge-diffracted rays and the launching coefficients for creeping waves on the convex side as well as WG modes on the concave side. These quantities are of interest for placing the results within the context of the geometrical theory of diffraction (GTD) and are relevant to the analysis of curved two-dimensional reflectors of finite width, where WG modes excited by diffraction of the incident field at one edge provide illumination of the other edge. The induced surface current density function is also derived. The asymptotic results, including an observed shift of the shadow boundary relative to the direction of incidence of the WG mode, are explained completely in terms of half-plane diffraction of one of the modal ray congruences, thereby confirming via this canonical problem the validity of the GTD for diffraction of modal fields. For the limiting case a \rightarrow \infty , all expressions are shown to reduce to those for the classical half-plane problem.
55 citations
TL;DR: The purple pigment of the gorgonianParamuricea chamaeleon has been isolated and identified as linderazulene (I).
Abstract: The purple pigment of the gorgonianParamuricea chamaeleon has been isolated and identified as linderazulene (I).
33 citations
01 Jun 1981
TL;DR: In this article, the authors presented a quasilinearization solution for vertical rectangular fin when condensation occurs, assuming that the average convective heat and mass transfer coefficients are constant along the height of the fin.
Abstract: There may be condensation on the fin surfaces of the air conditioning systems due to the temperature of the fin surfaces being below the dew point temperature of the water vapor in the surrounding air. Heat and mass transfer occur from the saturated air layer to the liquid water film and the latent heat of condensation is transferred to the fin. This study presents a quasilinearization solution for vertical rectangular fins when condensation occurs, assuming that the average convective heat and mass transfer coefficients are constant along the height of the fin. Rectangular fins with and without condensation on the surface have been compared and optimum fin dimensions have been given. The optimum fin length, the fin effectiveness and the average fin temperature in the case of condensation were found to be smaller than in the case of no condensation.
32 citations
29 citations
TL;DR: Methyl ethers of 6-hydroxykaempferol and quercetagetin and scutellarein were isolated from the leaves of Pulicaria dysenterica and the pattern of compounds is different from that previously recorded in the flowers.
22 citations
17 citations
TL;DR: The known compounds are quercetin 7,3′-dimethyl ether, querectin 3, 3,3´dimethyl- ether, isorhamnetin, quercettin 3.7´dimethyltimethyl ether (ISE), querceto-methyl ether (QME), quERCETin 3 β-glucoside (QBE), and quERCetin 3β-d−glucose (QDGL).
17 citations
TL;DR: In this paper, a ten-item, three-dimensional scale of political participation was developed for the first time, and the overall structure of the scale closely resembles the findings of Verba, Nie, and Kim.
Abstract: As an area which lends itself to empirical analysis, political participation has been subject to rigorous attempts at operationalization. In this article, an extension of these efforts is intended. Employing data collected in Kenya, Korea, and Turkey, a ten-item, three-dimensional scale of political participation is developed. The overall structure of the scale closely resembles the findings of Verba, Nie, and Kim—a fact which also lends support to the validity of the scale of political participation developed here. Easy to administer, valid, and reliable, the three-dimensional, ten-item scale provides a potential for cumulative analysis in the subfield of political participation.
TL;DR: In this article, the kinematic wave equations are solved using an implicit finite difference method for a diverging-converging surface, which is applicable to a natural watershed with a leaf-shaped geometry.
Abstract: For a diverging-converging surface, the kinematic wave equations are solved using an implicit finite difference method. This diverging-converging representation is applicable to a natural watershed that has a leaf-shaped geometry. The results are compared with other idealistic representations. These are: plane surface, diverging surface, and converging surface. The diverging-converging model gives hydrograph values between those of converging and diverging models, depending on the geometric parameters. In general, the geometry of a watershed has important effects on the runoff hydrograph for both equilibrium and partial equilibrium conditions.
TL;DR: In this paper, an analytical model was developed which describes the pressure behavior of a well located at the center of a multilayer region surrounded by a swept zone, and the results of injectivity and falloff tests were given.
Abstract: An analytical model was developed which describes the pressure behavior of a well located at the center of a multilayer region surrounded by a swept zone. The solution method for a circular well with a skin effect and wellbore storage is Laplace transformation followed by a numerical inversion scheme. Theoretical injectivity and falloff curves from such reservoirs are presented, and the influence of a skin effect and wellbore storage are also evaluated. The results of injectivity and falloff tests are given. Although the analytical model was used to simulate an in situ combustion operation, the results of this model would be ideal for any enhanced recovery processes dealing with a multilayer composite system similar to the studied stratified system with fluid banks. 11 refs.
TL;DR: The effects of lithium and chlorpromazine chronically administered alone and together on the dopamine metabolism in the rat striatum and frontal cortex were investigated by measurement of the levels of dopamine and its main metabolite, homovanillic acid.
Abstract: The effects of lithium and chlorpromazine chronically administered alone and together on the dopamine metabolism in the rat striatum and frontal cortex were investigated by measurement of the levels of dopamine (DA) and its main metabolite, homovanillic acid (HVA). Long-term chlorpromazine administration caused a significant increase in the striatal DA level and a decrease in that of HVA and HVA/DA ratio without any changes in those of the frontal cortex. The prolonged administration of lithium elevated the striatal levels of both HVA and DA, but no change in the frontal cortex was observed. The concurrent administration of chlorpromazine and lithium caused a significant increase in the frontal cortical DA level and a decrease in that of HVA and HVA/DA ratio. The striatal DA and HVA levels increased under the effect of the combined treatment, while the HVA/DA ratio remained unchanged.
TL;DR: In this article, the authors studied the a.c. polarization of anodic Al2O3 films in the thickness range 30-1500 A and the frequency range 300 Hz to 15 kHz and found that the interfacial polarization mechanism involving distinct regions separated by flaws and/or voids in the bulk was thought to become dominant with decreasing thickness.
TL;DR: This paper summarizes a comprehensive approach to and arranges systematically theories and techniques of planning and design (P and D) in terms of P and D theories, applied techniques and tools.
TL;DR: Serum IgG, IgA, and IgM levels have been measured in patients with brain tumours and only in astrocytomas have significant differences been found with respect to the other brain tumour types.
Abstract: Serum IgG, IgA, and IgM levels have been measured in patients with brain tumours. Only in astrocytomas have significant differences been found with respect to the other brain tumours. The specific elevation of IgM levels in astrocytoma grade III (X=313+36, n=4) and astrocytoma grade IV (X=671+ 146, n=4) in comparison with astrocytoma grade II (X=180, n=2) shows clear correlation with the malignancy of astrocytomas.
TL;DR: The results indicate that marasmic protein energy malnutrition may lead to defects in the hGH secretory function of the hypothalamopituitary axis.
Abstract: . Gunoz, H., Neyzi, O., Sencer, E., Molvalilar, S. and Argun, A. (Departments of Pediatrics and Internal Medicine, Istanbul Faculty of Medicine, University of Istanbul, Turkey). Growth hormone secretion in protein energy malnutrition. Acta Paediatr Scand, 70: 521,.–Plasma hGH levels were assessed in 15 infants with protein energy malnutrition following insulin induced hypoglycemia, arginine and L-Dopa provocation tests and intravenous glucose tolerance test. Fasting hGH levels were high in 85.7 % of the cases. An adequate hGH response to stimulation was obtained in only 42.8 % of the cases with insulin induced hypoglycemia; in 52.5 % with arginine; in 30.8 % with L-Dopa. Response to at least one type of provocation was obtained in all 5 cases to which all three tests were applied. Exaggerated or delayed response to provocative stimuli was also encountered in a number of the cases. Intravenous glucose tolerance test did not lead to suppression in hGH secretion or to increase in insulin secretion in these subjects. The results indicate that marasmic protein energy malnutrition may lead to defects in the hGH secretory function of the hypothalamopituitary axis.
TL;DR: The death of a sibling of the Gγ - δ0 β0-thalassemia homozygote with a diagnosis of thalassemia major suggests that both types of δ 0 β0 -thalasseia could follow a severe clinical and hematological course.
Abstract: Two homozygous δ0 β0-thalassemia patients, one with the GγAγ type and the other with the Gγ type, and their heterozygous parents are described. Red cell indices among the heterozygotes with the GγAγ type of δ0β0-thalassemia were markedly different from those in heterozygotes with the Gγ type. However, the imbalance in in vitro hemoglobin synthesis was quite similar in the two heterozygous conditions. The same was observed for the homozygous patients; the in vitro chain synthesis was severely imbalanced as seen in β-thalassemia major. The clinical and some of the hematological findings were milder in the Gγ-δ0 β0-thalassemia homozygote than in the GγAγ - δ0 β0-thalassemia homozygote. The death of a sibling of the Gγ - δ0 β0-thalassemia homozygote with a diagnosis of thalassemia major suggests that both types of δ0 β0 -thalassemia could follow a severe clinical and hematological course. The discovery of the Gγ type of δ0 β0-thalassemia in a Turkish child shows that two types of δ0 β0 - thalassemia can be fo...
TL;DR: A new anthraquinone, 1-hydroxy-2-hydroxymethyl-8-methoxyanthrquinone was isolated from the root of Digitalis davisiana as discussed by the authors.
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TL;DR: Kizilcamin lif morfolojisi ve odunundan sulfat selulozu elde etme olanaklari uzerine arastirmalar.
Abstract: Kizilcamin lif morfolojisi ve odunundan sulfat selulozu elde etme olanaklari uzerine arastirmalar
TL;DR: In this article, the Langevin noise analysis of a critical, infinite-length, zero-power line reactor is given using Langevin technique and a one-speed model is used and delayed neutrons are ignored.
TL;DR: Belgrad Ormani saricam tohum bahcesi ve bahcede ciceklenme ve tohum olusumundaki gelismeler uzerine bazi tespitler
Abstract: Belgrad Ormani saricam tohum bahcesi ve bahcede ciceklenme ve tohum olusumundaki gelismeler uzerine bazi tespitler
TL;DR: Kuzey Trakya orman yetisme bolgesinde granit anatasi ustundeki bir toprak katenasinin analitik olarak incelenmesi
Abstract: Kuzey Trakya orman yetisme bolgesinde granit anatasi ustundeki bir toprak katenasinin analitik olarak incelenmesi
01 Jan 1981