Validation of the DIFFAL, HPAC and HotSpot Dispersion Models Using the Full-Scale Radiological Dispersal Device (FSRDD) Field Trials Witness Plate Deposition Dataset.

Three atmospheric dispersion models--DIFFAL, HPAC, and HotSpot--of differing complexities have been validated against the witness plate deposition dataset taken during the Full-Scale Radiological Dispersal Device (FSRDD) Field Trials. The small-scale nature of these trials in comparison to many other historical radiological dispersion trials provides a unique opportunity to evaluate the near-field performance of the models considered. This paper performs validation of these models using two graphical methods of comparison: deposition contour plots and hotline profile graphs.

Properties of the transferrin associated with rat intestinal mucosa.

The transferrin that is isolated from washed intestinal mucosal cell preparations consists partly of a fraction that has properties distinguishing it from serum transferrin. The serum transferrin contaminating mucosal preparations, even when fully saturated with iron and in the presence of proteinase inhibitors, also acquires the properties of the mucosal transferrin when the mucosa is homogenised. The mucosal transferrin is modified by a single cleavage of the polypeptide chain yielding a disulphide-linked peptide of 6550 daltons linked to the parent protein by a disulphide bridge.

Cleavage of fibrin-derived D-dimer into monomers by endopeptidase from puff adder venom (Bitis arietans) acting at cross-linked sites of the gamma-chain. Sequence of carboxy-terminal cyanogen bromide gamma-chain fragments.

Puff adder venom contains a protease capable of cleaving the gamma-chain of cross-linked D-dimer, derived from the plasmin digestion of fibrin, into apparently symmetrical monomers. The cross-linked gamma-chains are separated in the process without apparent loss of mass and without loss of the substituent at the glutamine cross-link site, if fluorescent D-dimer (the lysine analogue dansylcadaverine used as substituent) is used as substrate [Purves, L. R.

Respiratory sensitivity before and after birth.

A description is first given of respiratory activity in the fetus and its control. Evidence suggests that when the fetus makes respiratory movements, it is in a state comparable to REM sleep in the newborn and adult and that in the alternating periods of apnoea, it is in quiet sleep. It does not appear that the respiratory movements are normally regulated by chemical or reflex, e.

Chemoreceptors and their reflexes with special reference to the fetus and newborn.

Such evidence as there is indicates that hypoxia excites peripheral chemoreceptors in the adult by causing a fall in the rate of oxidative phosphorylation and that this process is potentiated by a rise in PCO2 which most probably acts by altering intracellular pH. What is unclear is whether this occurs in Type I cells or in sensory fibres and whether either should be regarded as the primary receptor. There is also uncertainty about the role of noradrenaline and dopamine, which are stored and presumably secreted in the chemoreceptor complex: are they, respectively, excitatory and inhibitory transmitters or do they modulate an underlying chemoreceptive process? In the fetus, the carotid body chemoreceptors are largely insensitive despite an adequate chemical stimulus; they are activated at or shortly after birth by an unknown process and thereafter, in the newborn period, they appear to be involved in sensing chemical changes in arterial plasma and assisting in respiratory stability but there is some evidence that they only become fully effective some days or even weeks after birth.