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Notes: Low temperature scanning electron microscopy (LTSEM) has been used to analyze the superconducting properties of integrated magnetometers involving a dc superconducting quantum interference device. The study yielded spatially resolved information on the critical temperature Tc and critical current density Jc in the upper and lower superconducting layers of the YBa2Cu3O7−δ/SrTiO3/YBa2Cu3O7−δ structure. The Tc of the lower film was depressed by several kelvin, and the Jc of the upper film was lower where it crossed the edge of a lower YBa2Cu3O7−δ film covered with SrTiO3. A gradient in Tc was observed in the lower film near the edge of a via, arising presumably from oxygen diffusion during fabrication. © 1996 American Institute of Physics.

Notes: We have investigated La1.85Sr0.15CuO4−δ grain boundary Josephson junctions (GBJs) fabricated on [001] tilt SrTiO3 bicrystals with misorientation angles of 24° and 36.8°. The resistive transition and the current–voltage characteristics of the GBJs are found to be close to those predicted by the resistively shunted junction (RSJ) model. Their product of the critical current density, Jc, and the normal resistance times area ρn, scales proportional to about (Jc)q with q=0.5–0.6 similar to what is found for YBa2Cu3O7−δ GBJs. By analyzing Fiske resonances the Swihart velocity of the GBJs and the ab-plane London penetration depth of La1.85Sr0.15CuO4−δ are obtained to c¯=2.5×106 m/s and λL=200 nm at 4.2 K, respectively. © 1996 American Institute of Physics.

Notes: Associated with non-steady magnetohydrodynamic (MHD) flow in the liquid metallic core of the Earth, with typical relative speeds of a fraction of a millimetre per second, are fluctuations in dynamic pressure of about 103 N m−2. Acting on the non-spherical core-mantle boundary (CMB), these pressure fluctuations give rise to a fluctuating net topographic torque Lt(t) (i=1, 2, 3)—where t denotes time—on the overlying solid mantle. Geophysicists now accept the proposal by one of us (RH) that Li-(t) makes a significant and possibly dominant contribution to the total torque Li*(t) on the mantle produced directly or indirectly by core motions. Other contributions are the ‘gravitational’ torque associated with fluctuating density gradients in the core, the ‘electromagnetic’ torque associated with Lorentz forces in the weakly electrically conducting lower mantle, and the ‘viscous’ torque associated with shearing motions in the boundary layer just below the CMB. the axial component L3*(t) of Li* (t) contributes to the observed fluctuations in the length of the day [LOD, an inverse measure of the angular speed of rotation of the solid Earth (mantle, crust and cryosphere)], and the equatorial components (Li* (t)) L* (t) contribute to the observed polar motion, as determined from measurements of changes in the Earth's rotation axis relative to its figure axis.In earlier phases of a continuing programme of research based on a method for determining Li(t) from geophysical data (proposed independently about ten years ago by Hide and Le Mouël), it was shown that longitude-dependent irregular CMB topography no higher than about 0.5 km could give rise to values of L3(t) sufficient to account for the observed magnitude of LOD fluctuations on decadal time-scales. Here, we report an investigation of the equatorial components (L1(t), L2(t)) = L(t) of Li(t) taking into account just one topographic feature of the CMB—albeit possibly the most pronounced—namely the axisymmetric equatorial bulge, with an equatorial radius exceeding the polar radius by 9.5 ± 0.1 km (the mean radius of the core being 3485 2 km, 0.547 times that of the whole Earth). A measure of the local horizontal gradient of the fluctuating pressure field near the CMB can be obtained from the local Eulerian flow velocity in the ‘free stream’ below the CMB by supposing that nearly everywhere in the outer reaches of the core—the ‘polosphere’ (Hide 1995)—geostrophic balance obtains between the pressure gradient and Coriolis forces. the polospheric velocity fields used were those determined by Jackson (1989) from geomagnetic secular variations (GSV) data on the basis of the geostrophic approximation combined with the assumption that, on the time-scales of the GSV, the core behaves like a perfect electrical conductor and the mantle as a perfect insulator.In general agreement with independent calculations by Hulot, Le Huy & Le Mouël (1996) and Greff-Lefftz & Legros (1995), we found that in magnitude L (t) for epochs from 1840 to 1990 typically exceeds L3(t) by a factor of about 10, roughly equal to the ratio of the height of the equatorial bulge to that strongly implied for irregular topography by determinations of L3(t) (see Hide et al. 1993). But L (t) still apparently falls short in magnitude by a factor of up to about 5 in its ability t o account for the amplitude of the observed time-series of polar motion on decadal time-scales (DPM), and it is poorly correlated with that time-series. So we conclude that unless uncertainties in the determination of the DPM time-series from observations-which we also discuss-have been seriously underestimated, the action of normal pressure forces associated with core motions on the equatorial bulge of the core-mantle boundary makes a significant but not dominant contribution to the excitation of decadal polar motion. Other geophysical processes such as the movement of groundwater and changes in sea-level must also be involved.

Notes: The banding pattern of Alu I-digested prepro-gonadotropin releasing hormone gene is species-specific in Atlantic salmon and brown trout and can be applied for identification of their hybrids.

Notes: A novel method, heteroduplex analysis, was applied for detecting variation in an amplified growth hormone (GH) gene segment of common bream Abramis brama. Two-allele polymorphism was detected within a 262 bp restriction fragment. The frequency of the variant haplotype in the Main River was 0–50 and in the Danube River 0–32, but the difference was Statistically not significant.

Notes: Zusammenfassung Menschliche Blutplättchen enthalten außer einer schwachen antifibrinolytischen Aktivität (nachweisbar in Urokinase- oder plasminhaltigen Systemen) eine starke Proaktivator-Aktivität (nachweisbar in Streptokinasehaltigen Systemen). Die antifibrinolytische Komponente wird durch Erhitzen (15 min, 80° C) nicht zerstört und ist nicht auswaschbar; sie kann durch die Proaktivator-Aktivität überdeckt werden. Diese letztere ist hitzelabil, durch Waschen graduell, aber nicht vollständig zu entfernen; sie wird möglicherweise aus dem Plasma adsorbiert. Die Bedeutung des hohen Proaktivatorgehaltes für die klinische Anwendung von Streptokinasepräparaten wird kurz diskutiert. Eine ausführliche Darstellung unserer Untersuchungen ist in „Thrombosis et Diathesis haemorrhagica“ vorgesehen.

Notes: Abstract The unorthodox two-component sensor protein BvgS ofBordetella pertussis contains several interesting sequence motifs of unknown functional relevance, such as a histidine motif in its output domain, which is conserved among several unorthodox sensor proteins, a putative nucleotide binding site [Walker box type A] in its linker region, and a region in its periplasmic domain with significant homology to the TonB protein ofEscherichia coli. We investigated potential functions of these sequences by constructingB. pertussis strains that express mutant BvgS derivatives. The His1172 residue in the output domain was exchanged for Gln, and the Walker motif was mutated either by the replacement of Lys625 by Arg, or of Gly624 by Val and Lys625 by Leu. To analyse the TonB motif, the periplasmic domain of BvgS was replaced with the corresponding domain of EvgS, anE. coli sensor that is highly homologous to BvgS but lacks the similarity with TonB. All mutations except the conservative Lys/Arg exchange in the Walker box caused the inactivation of BvgS, indicating the functional importance of the conserved motifs. The activity of the mutant proteins could be restored by complementation in trans with various separately expressed, truncated parts of BvgS. Mutations in the BvgS receiver domain could be complemented not only by a construct expressing the wild-type receiver and output domains, but also by the derivative containing the His-Gln exchange. Therefore, the histidine motif, although important for BvgS function, is not essential for complementation of BvgS mutants. The mutations in the Walker box and in the periplasmic domain could be complemented by a truncated BvgS derivative lacking the receiver and output domains. The characterization of a spontaneous revertant of the strain expressing the originally inactive EvgS/BvgS hybrid protein revealed the presence of a mutation in the BvgS linker region, conferring constitutive activity on the protein. As TonB energizes transport processes across the outer membrane ofE. coli, the strain expressing the constitutive EvgS/BvgS hybrid protein lacking the TonB motif was used in preliminary investigations of a possible direct involvement of BvgS in transport processes.