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A 65-year-old restrained female driver hit the steering column in a high-speed head-on collision. She presented to our center complaining of anterior chest pain with findings of a left chest wall contusion and persistence of her known systemic arterial hypertension. A chest radiograph showed bilateral rib fractures, right pneumothorax, and an abnormal mediastinum. Aortography showed a focal outpouching along the posterior mid descending thoracic aorta. The ulcer showed only minimal delay in contrast washout; no intimal flap was seen (Figs. 1A and 1 B). CT of the chest, performed without IV contrast, confirmed the focal outpouching ofthe aortic lumen and showed no peniaortic hematoma (Fig. 1C). Because of the magnitude and mechanism of injury and uncertainty about the angiographic diagnosis, the patient underwent an exploratory thoracotomy. No mediastinal hematoma was present. The external aortic wall was intact without adventitial discoloration. The region of the focal bulge of the descending thoracic aorta felt like a complex atheromatous plaque, compatible with a penetrating ulcer of the descending aorta (PUDA).

Activation calculations were performed f or 27 elements in the STARFIRE, Mirror Advanced Reactor Study (MARS), and GA Technologies, Inc. (GA) conceptual reactor first-wall neutron spectra. In all t...

The problem of optimizing electric propulsion heliocentric trajectories, including the effects of geocentric launch asymptote declination on launch vehicle performance capability, is formulated and a solution is developed using variational calculus techniques. The model of the launch vehicle performance includes a penalty associated with noneasterly launch plus another penalty arising from a noncoplanar launch from the parking orbit. Provisions for range safety constraints are included. The solution of the resultant optimization problem requires that the launch excess velocity be offset from the initial primer vector. Mission performance for example cases shown indicate a small to moderate performance degradation compared to corresponding cases where declination effects are ignored.

The chelating diarsine 2,2′-bis(dimethylarsino)biphenyl (dmab) forms a series of complexes with NiII of composition [NiX2(dmab)2](X = Cl, Br, I, or NCS) which are assigned a pseudo-octahedral structure on the basis of spectroscopic and magnetic-moment data. In solution in organic solvents the complexes dissociate to varying extents to form five-co-ordinate species. In addition, a series of diamagnetic five-co-ordinate complexes of composition [NiX(dmab)2][ClO4](X = Cl, Br, or I) have been prepared, and are assigned a trigonal-bipyramidal structure on the basis of electronic spectra. The diarsine also forms a diamagnetic square-planar complex [Ni(dmab)2][ClO4]2 which on treatment with iodide ion is converted into the five-co-ordinate [Nil(dmab)2][ClO4].

To define the most cost-effective means of diagnosing and following gastric ulcers, both benign and malignant, the University of Utah Medical Center (UUMC) experience between September 1980 and October 1983 was reviewed. Endoscopy (EGD) was utilized in the initial evaluation process in 96% of patients. Follow-up was performed by either a combination of EGD and double contrast upper GI (DCUGI) or EGD alone. Diagnostic and follow-up modality had no effect on survival. It appears that the high-frequency use of EGD for gastric ulcer management is not cost-effective. We suggest an algorithm in which EGD would be used only following failure either to demonstrate characteristic benign appearance on DCUGI or inadequate healing following therapeutic trial. A theoretical net savings of 55% is calculated by retrospective application of the algorithm to the UUMC experience; 30% savings is realized for diagnosis and 81% for follow-up. If adopted on a national scale, the algorithm proposed may result in a significant savings in health-care cost.

Recently evaluated and model estimated precursor data are used with preliminary ENDF/B-VI fission yields to calculate total and time-group anti nu/sub d/ and spectra. 8 refs.

The activation of 27 elements (Li, Be, B, C, N, O, Mg, Al, Si, P, S, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Sn, Hf, Ta, W, and Pb) was calculated for a two-year exposure at the STARFIRE first-wall position. Based on a reasonable extension of current NRC regulations for near-surface land disposal, restrictions on N, Al, Ni, Cu, Nb, Mo and Pb concentrations in first-wall materials may be required.

The purpose of this paper is to describe the framework within which the development of alloys exhibiting reduced activation is being pursued in the US and to survey the current status and future prospects of this effort. The goal is to reduce activation to a level precluding the need for geologic disposal in order to help make fusion power environmentally and economically attractive. Initial efforts at reducing activation are aimed at replacing problem elements — especially Nb, Mo, and Ni — with more benign elements in analogues of structural alloys such as Ti-modified 316 stainless steel, the ferritic/martensitic steels containing 9–12% Cr, and the lower Cr (2%) ferritic/bainitic steels. The intrinsically low activation vanadium alloys are also under study; these are not common structural materials, so a data base is only slowly accumulating. Although this work is at an early stage, it provides evidence for optimism that the goal can be met.

The US Fusion Materials program recently adopted a requirement that structural alloys qualify for shallow land burial at the end of their life. In the absence of a directly applicable regulation, the activation limits currently being used are taken from a US Nuclear Regulatory Commission regulation, 10CFR61, developed to handle existing waste streams from the commercial nuclear industry. Activation calculations are characterized by many uncertainties, e.g., in nuclear data, in handling of multi-step reactions, in appropriate neutron flux-spectra, in component lifetimes, and in the viability of isotopic tailoring. These uncertainties, coupled with uncertain regulatory criteria, mean that calculated concentration limits should be viewed only as a qualitative guide in developing reduced activation materials.

The existence of complex compounds of metallic salts with ammonia was recognised in the early years of last century. Platinum in particular readily unites with ammonia, and the early chemists, when studying the general chemistry of ammonium platino-and platini-chlorides, soon discovered highly crystalline ammonia derivatives of platinum which contained an unusually high proportion of the metal. In the formulation of such compounds difficulties at once arose. Thus Peyrone in 1844 knew three distinct compounds of the composition PtCl2N2H6, a pale lemoncoloured compound known as the second chloride of Reiset, an orange-coloured compound discovered by Peyrone himself, and finally a dark green insoluble substance known as Magnus' green salt, discovered by the latter in 1828. The existence of these three compounds, now known as trans and cis dichloro-diaminoplatinum [Pt(NH3)2Cl2], and as tetramino-platinous platinochloride [Pt(NH3)4]PtCl4 respectively, could not be satisfactorily explained on current theories of salt formation. Similar compounds in which aliphatic and cyclic mono-amines replaced the ammonia groups were discovered later, but it was not until 1889 that Jörgensen introduced the use of the simplest stable aliphatic diamine, viz. ethylene diamine.

The 1 : 1 complexes of the chelating diphosphine, 2,2′-biphenylylenebisdiethylphosphine, with nickel(II) halides and thiocyanate and with palladium(II) bromide have been prepared, and their magnetic properties and electronic and n.m.r. spectra studied.The nickel(II) chloride and bromide complexes in solution exhibit square planar-tetrahedral isomerism, while the corresponding iodide and thiocyanate complexes remain exclusively tetrahedral and square-planar respectively. The palladium(II) bromide complex has the square-planar configuration.A brief study has been made of the chelating properties of the analogous diarsine. This gives a stable 1 : 1 complex with palladium(II) bromide but does not apparently give 1 : 1 nickel(II) halide complexes.

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The co-ordination theory of Werner (‘Ann.,’ vol. 322, p. 261 (1902)) has led to a great advance in our knowledge of complex metallic compounds; as applied to such compounds as hexamminocobaltic chloride [Co(NH 3 ) 6 ]Cl 3 , it involves the assumption that the six component ammonia groups are situate at the apices of a regular octahedron of which the cobalt atom occupies the centre, and that the complex so constituted—the co-ordinated group—acts as a tribasic ion which combines as a whole with three equivalents of an acidic radicle. For the purpose of discussing the possibilities of geometrical arrangement of the component parts of a co-ordinated group, it will be convenient to number the octahedron apices in the following manner. The outline of the plan of a regular octahedron on one of its triangular faces is bounded by a regular hexagon, each apex of which represents an angular point of the octahedron; let these latter points be numbered consecutively from one to six. On the basis of this nomenclature the isomeric praseo- and violeo-compounds of the composition, [Co(NH 3 ) 4 Cl 2 ]Cl, become, respectively, the 1 : 2 : 4 : 5- tetrammino-3 : 6-dichlorocobaltic chloride and the 1 : 2 : 3 : 5-tetrammino- 4 : 6-dichlorocobaltic chloride. Werner’s theory indicates the possibility of stereoisomerism, accompanied by optical activity, when certain of the six ammonia groups in hexamminocobaltic chloride are replaced by differently constituted radicles; in this respect a close correspondence has been observed between theoretical anticipation and experimental results. A similar concordance between prevision and realisation has been found among compounds in which pairs of ammonia groups in the hexamminocobaltic chloride are replaced each by one molecule of ethylenediamine; theory indicates that the tere thylenediaminecobaltic chloride, [Co(NH 2 .CH 2 .CH 2 .NH 2 ) 3 ]Cl 3 , should be resolvable into enantiomorphously related components which contain the 1 : 2, 3 : 4, 5 : 6- and the 2 : 3, 4 : 5, 6 :1- tere thylenediaminecobaltic co-ordinated groups respectively, and salts of these two optically active radicles have been prepared.

We have recently shown (‘Roy. Soc. Proc.,’ A, 1924, vol. 107, p. 80) that 1:2:3-triaminopropane forms co-ordination compounds with certain trivalent metals, such as cobalt and rhodium; these compounds are of the general type of bis -propanetriamine cobaltic chloride, [Co 2(NH 2 .CH(CH 2 .NH 2 ) 2 )] Cl 3 , in accordance with Werner’s theory of co-ordination. In these compounds the triaminopropane behaves in a similar way to ethylenediamine, each amino-group taking part in the formation of the co-ordinated radicle. It is thus seen that the grouping, NH 2 .CH 2 .CH.NH 2 , which is present twice in the triamino- propane molecule, behaves for co-ordination purposes in the same way as the molecule of ethylenediamine, NH 2 .CH 2 .CH 2 .NH 2 . This analogy in behaviour appears worthy of further investigation, and we have therefore studied the manner in which β β' β"-triaminotriethylamine, N(CH 2 .CH 2 .NH 2 ) 3 , co-ordinates with the metals; in this substance the grouping, NH 2 .CH 2 .CH 2 .N:, occurs three times, but it would seem that the presence of the three primary amino-groups has greatly diminished the basic properties of the tertiary amino-radicle, since Ristenpart (‘Ber.,’ 1896, vol. 29, p. 2530) obtained only salts in which the substance acts as a tribasic amine. It might thus be anticipated that co-ordinated salts of the type I would be formed.