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  • 1
    Electronic Resource
    Electronic Resource
    NADPH-diaphorase and NOS enzymatic activities in some neurons of reptilian gut and their relationships with two neuropeptides (1999)
    Springer
    Anatomy and embryology 199 (1999), S. 397-405 
    Details
    ISSN: 1432-0568
    Keywords: Key words Reptiles ; Gastrointestinal tract ; Nitric oxide ; VIP ; Galanin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The distribution of neurons containing the enzymes NADPH-diaphorase (NADPH-d) and nitric oxide synthase (NOS) has been studied in the gastrointestinal tract of lizard (Podarcis s. sicula) and snake (Thamnophis sirtalis). The techniques employed were the NADPH-d/nitroblue tetrazolium histochemical method, and the indirect immunofluorescence applied to cryostat sections and to whole-mount preparations. The colocalization of NADPH-d with NOS, with vasoactive intestinal polypeptide (VIP) and with galanin (Gal) was also studied, and a Western blot analysis using an antibody directed against mammalian Gal was performed on lizard stomach extracts. NADPH-d positive nerve cell bodies and fibres were found in the myenteric and submucous plexuses throughout the gastrointestinal tract of both reptiles. These nerve structures were also present in the other intramural nerve plexuses, although in smaller quantities. Both in lizard and snake, the stomach revealed a positive nerve population that was more dense than elsewhere in the gut. The population of the NADPH-d-positive neurons observed in the lizard was larger than that observed in the snake. The distribution of both populations was similar to those that have been described in the gut of several mammalian and non-mammalian vertebrates. Both in lizard and snake, a one-to-one correspondence was noted between NOS- and NADPH-d-containing nerve cell bodies, and the nitrergic neurons containing Gal appeared to be more numerous than those containing VIP. Western blot analysis recognised a single band with a molecular weight (3.4 kDa) very similar to that of porcine Gal. It is hypothesised that at least some of the nitrergic neurons of the lizard and snake gut are inhibitory motor neurons innervating the circular smooth musculature. In addition, the colocalization of NOS and VIP in neurons enhances their inhibitory action. The role of the neurons containing both NOS and Gal remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050238
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  • 2
    Electronic Resource
    Electronic Resource
    High-temperature properties of GaInAs/AlGaAs lasers with improved carrier confinement by short-period superlattice quantum well barriers (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 2863-2865 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The influence of the carrier confinement on the output characteristics of GaInAs/AlGaAs lasers was investigated. To improve the carrier confinement, AlGaAs/GaAs short-period superlattices were used as quantum well barriers. In comparison to lasers with GaAs barriers the structures with the modified barriers show improved temperature properties at low threshold current densities without deterioration of the internal quantum efficiency (〉95%). High characteristic temperatures (T0) well above 300 K were measured between 20 and 75 °C and laser operation up to 238 °C could be achieved. The large improvement in T0 is mainly attributed to the reduced thermionic emission of carriers out of the quantum well due to the increased barrier height and the carrier reflection above the barrier by the short-period superlattice. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.122611
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  • 3
    Electronic Resource
    Electronic Resource
    Magnetic-field-effect three-terminal device based on YBa2Cu3O7−δ grain boundary junctions (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 1843-1845 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Three-terminal YBa2Cu3O7−δ thin film devices based on a parallel array of grain boundary Josephson junctions were fabricated. The multiloop superconducting device is controlled by the magnetic field generated by a current Ictrl, which modulates the critical current Ic through the Josephson junction array. For these devices a current gain ranging between 2 at 77 K and 5 at 30 K was obtained. The spatial homogeneity of the device properties was studied by low-temperature scanning electron microscopy and by the determination of the supercurrent correlation function. Comparing the measured and the theoretically expected supercurrent correlation function shows that the device characteristics agree well with those expected from the device geometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356326
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  • 4
    Electronic Resource
    Electronic Resource
    The Effect of NO-Donors in Bovine and Rat Pineal Cells: Stimulation of cGMP and cGMP-Independent Inhibition of Melatonin Synthesis (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neuroendocrinology 7 (1995), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The presence of soluble guanylate cyclase in the pineal and its regulation by adrenergic pathways has been well documented. Recent evidence points to adrenergically stimulated nitric oxide generation as a mechanism for coupling this pathway. To what extent nitric oxide (NO) signalling can influence adrenergically stimulated melatonin synthesis has not been investigated. Cyclic guanosine 3′,5′-monophospate (cGMP) signal transduction in the bovine pineal has also received little attention. We describe in the present report: 1) a dose-dependent elevation of cGMP in response to the nitrovasodilators, sodium nitroprusside (SNP) and 3-morpholino-sydnonimine (SIN-l), 2) a dose-dependent inhibition of melatonin synthesis by SNP and SIN-1, but not by 8-Br-cGMP in both bovine and rat pineal cell cultures, which is not due to cytotoxicity as judged by two different approaches, and 3) immunohistochemical evidence for the presence of nitric oxide synthase (NOS) (EC 1.14.23.-) in the intact bovine pineal gland and in cultured bovine pinealocytes. These data support the view that NOS is a component of the cGMP-generating system in mammalian pinealocytes. Although NO-donor molecules are also potent activators of cGMP accumulation, they may have other important actions in the pineal, namely the inhibition of adrenergic-stimulated melatonin synthesis. As SNP and SIN-1 exerted this inhibitory effect on cells regardless of whether they were stimulated by isoproterenol, forskolin or 8-Br-CAMP it would appear that NO-donors can act ‘downstream’ from the receptor/adenylate cyclase level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2826.1995.tb00749.x
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  • 5
    Electronic Resource
    Electronic Resource
    Electric field controllable Josephson junctions of high quality in high-Tc superconductors (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 3031-3033 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Three-terminal Josephson junctions, the third terminal of which can be used to control the electronic properties of the device, are the key to a number of exciting device applications of high-Tc superconductors. To this end a novel device structure has been developed, which consists of an inverted metal-insulator-superconductor field-effect transistor into which a bicrystal grain boundary junction is embedded. These devices are excellent Josephson junctions as exemplified by their current–voltage characteristics and the magnetic field dependencies of the critical currents. The critical current of the junctions can be changed by 8% per volt applied to the gate electrode, the gate currents being negligible. Because they are sensitive to electric as well as magnetic fields, the junctions can be controlled by two independent inputs. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115567
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of the critical current density in grain boundary Josephson junctions on a nanometer scale (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 2289-2291 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The critical current Ic of YBa2Cu3O7−δ bicrystal grain boundary Josephson junctions (GBJs) have been measured in high magnetic fields up to B=12 T. Even at the highest applied magnetic fields, Ic varied periodically with varying magnetic field. By comparing the envelope of the measured Ic(B) dependencies to model calculations we obtain information on the spatial distribution of the supercurrent density jc on a length scale down to below 1 nm. Our analysis gives clear evidence that jc has spatial inhomogeneities on all length scales down to 1 nm with a probability distribution p(a) for the characteristic length scale a of the inhomogeneities. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113263
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  • 7
    Electronic Resource
    Electronic Resource
    Superconducting transport properties of Bi2Sr2CaCu2O8+x bicrystal grain boundary junctions (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 996-998 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have performed a detailed study of the superconducting transport properties of Bi2Sr2CaCu2O8+x bicrystal grain boundary junctions (GBJs). The GBJs were fabricated by the deposition of c-axis oriented epitaxial Bi2Sr2CaCu2O8+x films on SrTiO3 bicrystal substrates. The measured resistive transition R(T), the current-voltage characteristics (IVCs), the temperature dependence of the critical current density Jc(T), and the magnetic field dependence of the critical current Ic(B) of the Bi2Sr2CaCu2O8+x GBJs are similar to those observed for YBa2Cu3O7−δ GBJs. However, for the same misorientation angle the magnitude of Jc is almost an order of magnitude smaller for the BSCCO-GBJs. The R(T) dependencies and the IVCs of the BSCCO-GBJs are close to the prediction of the resistively shunted junction (RSJ) model. The Ic(B) dependencies are close to those of large Josephson junctions with overlap geometry. Our results show that BSCCO-GBJs may be useful for cryoelectronic applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109818
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  • 8
    Electronic Resource
    Electronic Resource
    Magnetic field dependence of the critical current in YBa2Cu3O7−δ bicrystal grain boundary junctions (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 783-785 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have performed a detailed study of the magnetic field dependence of the critical current, Ic(B), of YBa2Cu3O7−δ bicrystal grain boundary junctions (GBJs). GBJs with width W much larger than the Josephson penetration depth λJ show Ic(B) dependencies that are close to those of ideal large Josephson junctions with overlap geometry. The Ic(B) dependencies are symmetrical with respect to B=0 and Ic decreases linearly with increasing applied magnetic field for B≤BJ1, where BJ1 is the lower critical field of the GBJ. Furthermore, Ic(B=0) increases linearly with increasing width of the GBJs as expected for Josephson junctions with overlap geometry. From the measured Ic(B) dependencies the temperature dependence of BJ1 and the London penetration depth could be derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108578
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  • 9
    Electronic Resource
    Electronic Resource
    Distribution of the critical current density and flux trapping in YBa2Cu3O7−δ ramp-edge Josephson junctions (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 241-243 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the spatial distribution of the critical current density in YBa2Cu3O7−δ ramp edge Josephson junctions using low-temperature scanning electron microscopy. Applying this technique allows the imaging of the critical current density distribution with a spatial resolution of about 1 μm. Our measurements show that the geometry of the ramp-edge junction eases the trapping of magnetic flux quanta in the YBa2Cu3O7−δ layer covering the ramp edge. These trapped flux quanta result in a spatially inhomogeneous magnetic field parallel to the barrier layer, which in turn results in a spatially modulated supercurrent density and an unusual magnetic field dependence of the critical current.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.111516
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  • 10
    Electronic Resource
    Electronic Resource
    Solubility and molecular modeling of triflumizole-β-cyclodextrin inclusion complexes (1995)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 22 (1995), S. 15-32 
    Details
    ISSN: 1573-1111
    Keywords: β-Cyclodextrin ; triflumizole ; host-guest complex ; inclusion complex ; solvent accessible surface ; solubility enhancement ; hydrophobic effect ; dynamic Monte Carlo molecular docking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Solubility enhancement of the fungicide triflumicole byβ-cyclodextrin is explained using a thermodynamic approach. The influence of organic cosolvents on the overall equilibrium constants of triflumizole complexation withβ-cyclodextrin in aqueous solutions has been investigated. Their variance in mixed solvents is only partly explained by a competitive inclusion of substrate and cosolvent molecules inβ-cyclodextrin. The geometries of host-guest complexes have been estimated by molecular mechanics calculations. Their broad structural variety caused by the flexibility of host and guest molecules and different association possibilities of triflumizole have been analysed by a dynamic Monte Carlo docking method. The hydrophobic effect has been simulated by cominimization of the hydrophobic contributions to the solvation energy, calculated from the solvent accessible surface area of the complex and the conformational (potential) energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00706495
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