Alpha-receptor subsensitivity of isolated atria from rats following repeated injections of phenylephrine or isoprenaline

Summary Daily injections of phenylephrine or isoprenaline for 4 or 7 days lowered the chronotropic sensitivity of -adrenoreceptors in isolated rat atria.This study was supported by grants from the National Science Council of Finland.     

In situ measurements of the physical characteristics of Titan's environment

On the basis of previous ground-based and fly-by information, we knew that Titan's atmosphere was mainly nitrogen, with some methane, but its temperature and pressure profiles were poorly constrained because of uncertainties in the detailed composition. The extent of atmospheric electricity ('lightning') was also hitherto unknown. Here we report the temperature and density profiles, as determined by the Huygens Atmospheric Structure Instrument (HASI), from an altitude of 1,400 km down to the surface. In the upper part of the atmosphere, the temperature and density were both higher than expected. There is a lower ionospheric layer between 140 km and 40 km, with electrical conductivity peaking near 60 km. We may also have seen the signature of lightning. At the surface, the temperature was 93.65 +/- 0.25 K, and the pressure was 1,467 +/- 1 hPa.     

CHARACTERISTICS OF AKD EMULSION PREPARED BY CATIONIC STARCH WITH WELL-DEFINED STRUCTURES

Alkyl ketene dimers (AKD) have been used in the papermaking industry as reactive internal sizing agents for more than 30 years. AKD emulsions are normally stabilised by cationic starch. The advantages and disadvantages of the emulsions prepared in this way have been well documented. However, the influence of factors such as electrolytes, polyelectrolytes oligomers and pH on AKD emulsion stability has not been addressed. Polyelectrolyte oligomers often arise as impurities in cationic starch or as by-products during the cationisation of starches. The key objectives of this work have been to use starches purified by dialysis and precipitation to study (a)emulsion stabilising properties, (b) factor affecting emulsion characterisation and (c) the adsorption behaviour on AKD particles.Size exclusion chromatography (SEC) and intrinsic viscosity measurements were performed to evaluate molecular weight and MW distribution of cationic starches. NMR and Elemental analysis were conducted to characterise the degree of substitution (DS), and electrophoresis mobility was used to measure the surface charge characteristics of the emulsion particles.Within the experimental concentration ranges, the amount of the cationic starch adsorbed on the AKD particle surfaces has been shown to increase proportionally with the addition level but a high proportion remained unabsorbed. Molecular weight and charge density of cationic starch have also been observed and shown to be important. The zeta-potential of the emulsion particles was strongly dependent on the concentrations of the electrolytes added as well as pH. Excessive electrolytes and extreme pH conditions tended to reduce the zeta potential of the AKD particles.     

The Role of Credit in Predicting US Recessions

We study the role of credit in forecasting US recession periods with probit models. We employ both classical recession predictors and common factors based on a large panel of financial and macroeconomic variables as control variables. Our findings suggest that a number of credit variables are useful predictors of US recessions over and above the control variables both in and out of sample. In particular, the excess bond premium, capturing the cyclical changes in the relationship between default risk and credit spreads, is found to be a powerful predictor of recession periods. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of conflict stress on adrenoreceptors and metabolic activity of the rat heart

Summary Exposure of rats to a conflict situation (electric shocks associated with water supply) increased the activities of oxidative enzymes and of heksokinase in the myocardium. The stress also led to subsensitivity of atrial -adrenoreceptors.     

Observational evidence for the accretion-disk origin for a radio jet in an active galaxy

Accretion of gas onto black holes is thought to power the relativistic jets of material ejected from active galactic nuclei (AGN) and the 'microquasars' located in our Galaxy. In microquasars, superluminal radio-emitting features appear and propagate along the jet shortly after sudden decreases in the X-ray fluxes. This establishes a direct observational link between the black hole and the jet: the X-ray dip is probably caused by the disappearance of a section of the inner accretion disk as it falls past the event horizon, while the remainder of the disk section is ejected into the jet, creating the appearance of a superluminal bright spot. No such connection has hitherto been established for AGN, because of insufficient multi-frequency data. Here we report the results of three years of monitoring the X-ray and radio emission of the galaxy 3C120. As has been observed for microquasars, we find that dips in the X-ray emission are followed by ejections of bright superluminal knots in the radio jet. The mean time between X-ray dips appears to scale roughly with the mass of the black hole, although there are at present only a few data points.     

Interactions between VEGFR and Notch signaling pathways in endothelial and neural cells

Notch cell interaction mechanism governs cell fate decisions in many different cell contexts throughout the lifetime of all Metazoan species. It links the fate of one cell to that of its neighbors through cell-to-cell contacts, and binding of Notch receptors expressed on one cell to their membrane bound ligands on an adjacent cell. Environmental cues, such as growth factors and extracellular matrix molecules, superimpose a dynamic regulation on this canonical Notch signaling pathway. In this review, we will focus on Notch signaling in the vertebrate vascular and nervous systems and examine its role in angiogenesis, neurogenesis, and neurovascular interactions. We will also highlight the molecular relationships of the Notch pathway with vascular endothelial growth factors (VEGFs) and their high-affinity tyrosine kinase VEGF receptors, key regulators of both angiogenesis and neurogenesis.