Showing papers by "Case Western Reserve University published in 1968"

Rates of change of eigenvalues and eigenvectors.

Abstract: Exact expressions for rates of change of eigenvalues and eigenvector to facilitate computerized design of complex structures

Physics of Electric Propulsion

Abstract: Book on physics of electric propulsion covering gas acceleration principles, flow heating and space thrustor design

The Influence of Chemical Agents on the Accumulation of Adenosine 3',5'-Phosphate in Slices of Rabbit Cerebellum

Abstract: Incubation of slices of rabbit cerebellum with norepinephrine for a few minutes resulted in large increases in the tissue content of adenosine 3',5'-phosphate. Exposure of slices to norepinephrine for more than 6 min led to a progressive disappearance of this nucleotide. Theophylline, a known inhibitor of cyclic-3',5'-ribonucleotide phosphodiesterase, had relatively little effect by itself upon the slice content of adenosine 3',5'-phosphate, but potentiated the effects of norepinephrine severalfold. In a survey of substances known to occur in the central nervous system, histamine, and to a lesser extent serotonin, were observed to produce effects similar to those of norepinephrine. The effects of histamine and norepinephrine were additive; phenoxybenzamine and diphenhydramine were observed to inhibit the effects of histamine at concentrations having relatively little influence on the action of norepinephrine while dichloroisoproterenol specifically prevented the effects of norepinephrine. Prolonged exposure of slices to norepinephrine desensitized slices to the readdition of norepinephrine, but not to histamine and vice versa. ACKNOWLEDGMENTS This work was supported in part by Grants AM-06141, NB-05716, and GM-661 from the U.S. Public Health Service. The authors also wish to acknowledge the skillful technical assistance of Mrs. Arleen Maxwell Haley and Mr. George Thorne in carrying out this work.

Disappearance rates of endogenous luteinizing hormone and chorionic gonadotropin in man.

Abstract: Assessment of the rates of disappearance of endogenous LH and HCG from serum following complete surgical hypophysectomy and removal of the placenta was made. The hormone levels were measured by a specific radioimmunoassay. The disappearance rates for both LH and HCG appear to follow a double exponential curve although there may be a possible additional exponential. The initial disappearance involves a fast process (t½ about 21 min for LH, t½ about 11 hr for HCG) followed by a slower process of disappearance (t½ about 235 min for LH, t½ about 23 hr for HCG), which probably reflects the distribution of these hormones in at least 2 compartments.

The normal microcirculation of diaphyseal cortex and its response to fracture.

Abstract: The normal patterns of arterial and capillary blood supply of canine diaphyseal cortex and the effect of fracture on these patterns have been described by means of microangiograms. Primary arterioles of medullary origin arborize within the inner two-thirds to three-quarters of the cortex and then anastomose with the scattered blood vessels of the periosteal circulation derived from muscular arterial branches. The medullary circulation thus supplies the greater proportion of cortical bone, but function of the medulloperiosteal vascular anastomoses appears to be essential for blood to flow through the cortex in the vessels derived from the medulla. Interruption of the local periosteal circulation by tight application of a bone plate suppresses even the medullary blood supply of the cortex beneath the plate, whereas loosening of the plate allows ingrowth of new periosteal vessels and leads to filling of cortical vessels again at all depths. This observation supports the contention that blood flow through the cortex is normally centrifugal. However, the periosteal circulation appears to be able to maintain the vascularity of the outer third of the cortex by itself when medullary arterioles are obliterated by an intramedullary rod. Evidently, therefore, the usual direction of flow through the cortex can be reversed, as was also shown by Brookes, and this permits the periosteal circulation to revascularize the cortex when its medullary blood supply has been chronically inhibited. During the healing of undisplaced closed fractures, the medullary circulation remains dominant throughout. With displaced fractures, however, when the main medullary vessels are disrupted, an enhanced periosteal circulation, derived from torn muscles in the vicinity, becomes at first the primary source of blood for the area of healing. The early external callus receives its blood supply from the periosteal circulation through vessels which are oriented perpendicularly to the cortical surface. As healing progresses, the medullary circulation is re-established across the fracture or osteotomy site. This circulation continues to hypertrophy, while the temporarily increased periosteal circulation recedes, and soon the medullary system provides all the blood for the areas of most effective osseous bridging. Eventually, the medullary circulation comes to be the main supplies of blood even to external callus through arterial branches which traverse the porous cortex, thereby carrying to the extreme the basic centrifugal trend of the blood supply of tubular bone. Finally, as late bone remodeling advances, the normal vascular pattern is reestablished with medullary vessels meeting periosteal vessels in vital anastomoses within the outer cortical layers. It is idle to argue whether the medullary or periosteal circulation is the more important in the blood supply of tubular bone. While medullary vessels are distributed to the greater portion of the normal cortex, they appear to require their periosteal anastomoses to function properly. The anatomic ascendency of the medullary circulation is even more obvious during the course of bone repair; but here also periosteal connections are probably essential, since, when medullary arterioles are supplying large masses of external callus, the flow of blood surely must still be outward. When the normal outward flow of blood through the cortex is blocked, the periosteal arterioles have more ability than medullary arterioles to function and proliferate; the direction of blood flow therefore reverses and becomes inward. The final conclusion, therefore, is that the medullary supply of the diaphyseal cortex, when available, dominates the anatomic vascular picture, but the periosteal supply has under adverse conditions greater staying power.

Protein uptake into multivesicular bodies and storage granules in the fat body of an insect

Abstract: The fat body in Calpodes ethlius (Lepidoptera, Hesperiidae) takes up protein from the blood throughout the larval stage before pupation. Depending upon the phase of development, the protein appears in multivesicular bodies, in large storage granules, and in structures of intermediate form. There are three phases in the 8 days of the last larval stage; the first devoted to growth (molting to 66 hr), the second to synthesis for storage or export (M + 66 to M + 156 hr), and the third to preparation for pupation (M + 156 to pupation at M + 192 hr). From M + O to M + 156 and from M + 180 to M + 188 hr, protein is taken up into multivesicular bodies. Larger MVB's form a continuous series with the protein granules formed from M + 162 to M + 180 hr. Blood proteins increase in concentration and amount from M + 66 to M + 156 hr at the same time as the fat body cells have a high rate of incorporation of amino acids and a structure appropriate for protein synthesis. During granule formation, both amino acid incorporation and blood protein concentration decrease. Since foreign proteins injected into the blood appear in the granules, they are probably made mainly from sequestered blood. Protein uptake involves two stages: concentration between the cells, and ingestion in pinocytotic vesicles. The vesicles fuse to become MVB's or storage granules, depending upon their rates of growth and the addition of lytic enzymes. Since MVB's do not accumulate in the fat body and since many of them contain acid phosphatase and appear empty, they are presumed to be concerned in protein turnover.

Numerical methods of high-order accuracy for nonlinear boundary value problems

Abstract: with Dirichlet boundary conditions d D~u(O) = D k u ( l ) -0, D ........ dx' O ~ k < ~ n t , (/.2) where (1.3) ~Eu (x)~ = Z ( l)J+lDJEpj(x) DJu(x)l, n==_t. i=0 Basically, the Rayleigh-Ritz-Galerkin method for (1.1)--(1.2) was applied in [4] to a variety of finite dimensional subspaces, such as polynomial and spline subspaces, these subspaces having been selected in part with an eye toward efficient digital computation. Our aim here is simply to extend the results of [4] to nonlinear boundary conditions. Although such extensions will be explored more fully in [5], we restrict ourselves here, for ease of exposition, to the case n = t of (1.1), i.e.,

The polymorphism of poly(vinylidene fluoride). I. The effect of head-to-head structure

Abstract: The phenomenon of polymorphism in poly(vinylidene fluoride) has been observed recently by several authors. It has also been reported that high-resolution NMR measurements demonstrate the presence in this polymer of head-to-head linkages, resulting from the “backward” addition of from 5-6% of the monomer units. Since the van der Waals radii of fluorine (1.35 A) and hydrogen (1.1-1.2 A) are similar, the cocrystallization in a polymer chain of units that differ only by the substitution of fluorine atoms for hydrogen atoms is not unexpected. The two polymorphic forms of poly(vinylidene fluoride), examined in this investigation, have different chain conformations. Chains in phase I have a planar zigzag conformation, while chains in phase II are assumed to exhibit a 21 helical conformation. The incorporation into the polymer chain of small amounts of tetrafluoroethylene or trifluoroethylene comonomer favored the crystallization of phase I. This is in accord with the relative abilities, deduced from con...

Studies on adenosine 3',5'-phosphate in rabbit cerebral cortex.

Abstract: Incubation of slices of rabbit cerebral cortex with histamine resulted in large accumulations of adenosine 3',5'-phosphate. Maximal levels of the nucleotide required about 15 min exposure to histamine and represented more than an 8-fold increase. Inclusion of theophylline (0.5 mM) in incubation media had little effect by itself on the accumulation of adenosine 3',5'-phosphate but increased the effect of histamine 3-fold. Norepinephrine increased the nucleotide level only about 70%, but only 2 min exposure to the agent was required to produce maximal values. This pattern of responses is in sharp contrast to that observed in cerebellar slices, but appears to be similar to that of other areas of rabbit brain. The content of adenosine 3',5'-phosphate in the cerebral cortex of rabbit heads frozen rapidly at intervals after decapitation rose about 8-fold within 90 sec after decapitation. Although phosphorylase a levels increased very rapidly after decapitation, no changes in phosphorylase a content of either cerebellar or cerebral cortex slices was detected under conditions producing large increases in adenosine 3',5'-phosphate. ACKNOWLEDGMENTS This work was supported in part by U.S. Public Health Service Grants AM-06141, NB-05716, and GM-661. The authors also wish to acknowledge the skillful technical assistance of Mrs. Arleen Maxwell Haley, Mr. George Thorne, and Mr. Neil Joebchen.

Components of Effectiveness in Small Organizations

Abstract: If it is to become effective in terms of survival and growth, an organization must fulfill (or satisfice) the needs and demands of its employees, its owners, and the relevant members of the society with which it transacts (its community, its governments, its customers, its suppliers, and its creditors). In this study, ninety-seven small-business organizations and their relevant societal components were surveyed in order to explore the extent to which the organization fulfilled the needs of these components. Data indicate relatively few significant relationships among various types of employee fulfillment, owner fulfillment, and societal fulfillment, and these few relationships are of a rather low magnitude. The feasibility of an organization concurrently fulfilling the variety of demands made upon it is discussed. The organization is viewed as an open system of interdependent components, with energy transfer within the organization as well as between the organization and the societal components. Frank Friedlander is associate professor of organizational behavior, school of management, at Case Western Reserve University, and Hal Pickle is associate professor in the department of business administration, Southwest Texas State College.

Critique on Theories Predicting Thermoelastic Properties of Fibrous Composites

Abstract: A critique on the theories predicting the thermoelastic properties of unidirectional fibrous composites is presented. The method of approach in these theories varies from netting analysis to complex statistical methods. This critique provides a concise description and evaluation of those theories which are instructive or illustrate an interesting approach in the prediction of the thermoelastic proper ties. It is intended to contribute to better understanding and judicious application of these theories, to familiarize the researcher with the state of the art and to provide him with a basis for future effort. Thermoelastic properties predicted by the various theories are arranged in check-list form for quick reference. Typical results are included for comparison purposes and current trends are dis cussed. References and publications which provide working equa tions and/or result comparison of these theories are cited.

A theory of modal control

Abstract: Although considerable progress has been made in various aspects of control theory, there still appears to be no adequate theory for the control of large-scale linear time-invariant multivariable systems. If the engineering specifications required of the controlled system can be effectively summarized in a quadratic performance measure, then linear optimal control theory, in principle, provides a linear feedback controller which would perform the required task. Even under these circumstances the computational problems may be insurmountable. In an effort to circumvent these difficulties Rosenbrock suggested the use of modal control as a design aid. Modal control may be defined as control which changes the modes (i.e., the eigenvalues of the system matrix) to achieve the desired control objectives. This paper presents a complete and rigorous theory of modal control as well as recursive algorithms which permit modal control to be realized.

Migration of lymphocytes and thymocytes in the rat i. the route of migration from blood to spleen and lymph nodes

Abstract: The cellular deficit in rats thymectomized at birth is primarily one of circulating small lymphocytes. The lymphocyte deficiency is similar to that induced in adult rats by chronic drainage from a thoracic duct fistula. In both cases, the animals show a reduction of small lymphocytes in peripheral blood, thoracic duct lymph, and in circumscribed areas of lymphoid tissue. The lympocyte deficiency in lymphoid tissue can be corrected by an intravenous injection of thoracic duct lymphocytes. The evidence suggests that the deficiency is corrected by small lymphocytes. Small lymphocytes pass from blood to lymphoid tissue along a route which includes the marginal sinus in splenic white pulp and postcapillary venules in the cortex of lymph nodes and Peyer's patches. Neither the ability of small lymphocytes to colonize lymphoid tissue nor their ability to traverse postcapillary venules are thymus-dependent phenomena. However, movement of small lymphocytes across postcapillary venules appears to modify the structure of endothelium. Intravenously injected small thymocytes migrate to lymphoid tissue in smaller numbers than small lymphocytes inoculated by the same route. The few thymocytes which localize in lymphoid tissue follow the same pathway as circulating small lymphocytes.

Insect salivary glands: stimulation of fluid secretion by 5-hydroxytryptamine and adenosine-3',5'-monophosphate.

Abstract: Low concentrations (10(-9)M) of 5-hydroxytryptamine increase the rate of fluid secretion by isolated salivary glands of adult Calliphora. 5-Hydroxytry ptamine is present in Calliphora brain. Adenosine-3',5'-monophosphate (cyclic AMP) also stimulates fluid secretion and may be involved in the mode of action of 5-hydroxytryptamine.

Some aspects of stereochemistry and hydrogen bonding of carbohydrates related to polysaccharide conformations

Abstract: Some general rules governing hydrogen bonding at the ring oxygens of furanosides, pyranosides, and bridge oxygens of glycosides have been formulated from existing data on crystal structures of carbohydrates. Ring oxygens of the majority of the glycopyranosides in the hemiacetal or acetal form are involved in hydrogen bonding such that the hydrogen bond direction is usually equatorial to the ring plane and not axial. In contrast, there are no known examples of ring oxygens of glycofuranosides and methyl-glycopyranosides displaying hydrogen bonding in the crystal. Also, the bridge oxygens of glycosides are not involved in hydrogen bonding. The observed shortening in the exocyclic and endocyclic anomeric C(1)O bonds and the geminal CO bonds indicate that compounds with two oxygen atoms attached to the same saturated carbon atom may participate in double-bond-no-bond resonance interaction in the same manner as difluoromethane. It is also possible that under these circumstances the carbon atom exhibits greater than tetracovalency. The “anomeric effect” may also be related to (a) the differences in the “double bonding” or bond shortening in the anomeric CO bonds of the anomeric glycopyranosides, (b) the shorter intramolecular O(1)…O(5) non-bonded interaction, and (c) the smaller O(1)C(1)O(5) valence angle in the equatorial anomer compared to the axial anomer. An analysis has been made of the energetically preferred conformations about the glycosyl and glycosidic bonds of 1,4- and 1,3-polysuc-charides. In the 1a, 4e-glycopyranosides the projected angle ϕ1 [O(5)C(1)OR, where R = C or H] is positive, while it is negative in the 1e, 4e-glycopyranosides. Angle ϕ2 [C(1)OC(4′)C(3′)] is positive in both the 1,4-anomeric polyglycosides. 1e, 4e- and 1a, 4e -polysaccharides are stabilized by intramolecular O(5)…HO(3′) and O(2′)…O(3′) hydrogen bonding, respectively, and generate linear and helical (cyclic) structures, respectively. 1e, 3e- and 1a, 3e-polysaccharides may be stablized by one of two possible intramolecular hydrogen-bonding schemes such that the 1a, 3e -polysaccharides generate helical structures while the 1a, 3e-polysaccharides generate nonhelical structures. The conformation about the C(5)C(6) bond in the pyranosides falls into two groups where the angle ϕ00 [O(5)C(5)C(6)O(6)] is either positive, ∼+60 ± 30°, or negative, ∼–60 ± 30°, the former conformation being found more frequently. In the furanosides the latter conformation is preferred.

Microangiography in Bone Healing

Abstract: The blood supply of healing undisplaced closed fractures of the radius and tibia in adult mongrel dogs was studied by means of microangiograms and histological preparations. The microangiograms were prepared from decalcified longitudinal slices across the fracture site, one millimeter in thickness. The corresponding histological preparations were made from the same slices of tissue. The vascular pattern at the site of fracture, at intervals from one day to eight weeks after fracture, was compared with the normal vascular pattern. Immediately after fracture there was a marked opening up of the existing arterial tree. With the advancement of healing, both medullary and periosteal circulations increased greatly by the development of new blood vessels; but the medullary arterial system, when intact, played the major role in the supply of blood to the uniting callus and in the revascularization of the necrotic cortex at the fracture site. The ascendency of the medullary blood supply increased as healing progressed. In the dog the normal configuration of the blood supply of the compacta is similar to that in man; the inner two-thirds of the cortex is supplied by branches of the nutrient artery. Our experimental findings in the dog support clinical experience. The periosteal circulation of long bones can take over when the medullary circulation has been interrupted by displacement of the fracture fragments or by surgery—as will be described in subsequent reports of experiments in progress. However, the medullary arterial supply, when available, dominates the vascular picture in rapid fracture healing.

Steroid Formation by Isolated and Recombined Ovarian Granulosa and Thecal Cells

Abstract: Granulosa and thecal cells were isolated from 2 human ovarian follicles and the separated and recombined cells were incubated in vitro with acetate-1-14C. Radioactively labeled cholesterol, pregnenolone, progesterone, 17-hydroxyprogesterone, androstenedione and estrone were isolated in radiochemically pure form from each of the experimental situations utilizing either granulosa, theca or a mixture of the 2 cell types. In addition, labeled dehydroepiandrosterone was isolated only from the incubation with granulosa cells, while labeled estradiol-17β was isolated only from the thecal cell and recombined studies.

The two juvenile hormones from the cecropia silk moth.

Abstract: Some years ago we reviewed the status of the insect juvenile hormone (JH) and its isolation.1 Since then two noteworthy contributions toward purification of the hormone have appeared.2' In all these purification attempts adult male Cecropia silk moths4 proved to be an invaluable source material. The first nearly pure hormone preparation was isolated in 1965.1 We obtained it from Cecropia oil (second batch) and characterized it by means of a gas-liquid chromatographic (GLC) analysis in conjunction with an ultrasensitive argon ionization systemA The hormonal activity was located exclusively in the two major peaks B and E. Both these substances had a specific activity of the same magnitude as the original preparation. They were retained on neopentyl glycol adipate (NGA) columns at ratios of 1.60 and 1.29 relative to methyl stearate. Only one contamination, peak H, was apparent, which amounted to less than 10 per cent of the total peak area. Thus our 3 X 105-fold enriched preparation was at least 90 per cent pure. A host of subsidiary gas chromatographic peaks (A,D, etc.) were artifacts that resulted from reactions of the active compounds in the analytical system. These substances were produced even though the hormonal preparations had been injected with a Hamilton syringe directly onto the packed glass columns, but they were more plentiful in the fractions that had been previously submitted to a GLC separation and collected after passage through the brass detector cell. Since the same pyrolytic products were formed whether they were derived from compound B or compound E, the two hormonally active compounds had to be closely related structurally. We have now processed a new (third) batch of Cecropia oil by a five-step purification sequence similar to that applied to the second batch. These steps w-ere: (I) molecular distillation at -1 mTorr and 1000C; (II) separation from acidic products formed; (III) leaching with cold aqueous methanol; (IV) SiO2 chromatography; and (V) A1203 chromatography. One modification had been made in step IV in which an improved silica gel system was substituted for the zinc carbonate sy-stem6 previously used. This resulted in eliminating compound H. In the Galleria N-lX test, fractions of the final preparation again exhibited a potrency of some 3 X 105 JH units per milligram (Table 1). Our GLC unit wsas perfected by construction of a metal-free injector and a glass effluent splitter. As a result, the hormone preparation could be processed through the system without contacting any metal. From then on, much simplified chromatograms have been recorded (Fig. 1). The GLC analysis of the biologically most active fractions of the pure preparation revealed that they were composed of only two substances: compounds B and E (Table 1). When the

Kinetics of the reaction of renin with nine synthetic peptide substrates

Abstract: A number of peptides have been synthesized which represent portions of the tetradecapeptide renin substrate molecule, and which contain the hydrolyzable leu-leu bond. An automatic chemical method for determination of the velocity of the reaction of renin with these compounds was developed. Application of the method at several levels of substrate concentration permitted construction of Lineweaver-Burk plots, and calculation of Michaelis constants (Km) and maximal velocities (Vmax). The results show that the maximum affinity of the enzyme (lowest Km) for substrate is achieved only with the full tetradecapeptide molecule (asp1-arg2-val3-tyr4-ileu5-his6-pro7-phe8-his9-leu10-leu11-val12-tyr13-ser14). Removal of asp1 and arg2 from the N-terminal increases the Km eight-fold. Further, moderate increase in Km occurs when the next amino acids, val3, tyr4 and ileu5, are removed. The further removal of his6 results in a marked reduction in the Vmax. Removal of ser14 from the C-terminal of the nonapeptide his6-pro7-phe8-his9-leu10-leu11-val12-tyr13-ser14 does not greatly affect the Km nor the Vmax. Further removal of tyr13 from this compound results in complete loss of substrate activity. It is suggested that the compounds his6-pro7-phe8-his9-leu10-leu11-val12-tyr13-ser14 or his6-pro7-phe8-his9-leu10-leu11-val12-tyr13 might be used as substrates for the chemical assay and standardization of renin.