The Effects of Lubricant Rheology on the Performance of Journal Bearings

Experiments have been carried out on a relatively simple journal bearing rig to test the theory that extra load-carrying capacity is generated the elasticity of viscoelastic lubricants. Model lubricants were used. The viscoelastic lubricants were solutions of high-molecular-weight polyisobutene in low-molecular-weight polyisobutene while the inelastic lubricant was low-molecular-weight polyisobutene.

The extra load-carrying capacity has been established. An analysis of the detailed results strongly indicates that the extra benefit of elasticity is much greater than that predicted by existing theory.     

Revised calculation route for two group macroscopic cross-section library for RBMK-1500 type reactor

To increase the accuracy of predicted reactivity effects and coefficients for the unit equipped with a RBMK-1500 type reactor at Ignalina NPP, the calculation route used to generate the library of nuclear data constants applied in the neutronic/thermal hydraulic analysis has been updated with a modern version of the WIMS lattice code, WIMS8. The previously available two group library used with the QUABOX/CUBBOX-HYCA code, adapted to model the physical and nuclear processes in a RBMK-1500 reactor core, was created using the freely available WIMSD reactor physics cell code and its associated nuclear data library. In this article, the results that are obtained under the performance of the new two group cross-section library generated with WIMS8 for RBMK-1500 design core are presented. This discussion is mostly concentrated on the prediction of the key physics parameter for the RBMK type reactor, the void reactivity coefficient, as this parameter has been underestimated, especially at higher fuel irradiation.     

Cardiovascular effects of a new inotropic agent, U. K. 14275, in patients with coronary heart disease

1 The chronotropic and inotropic properties of U.K. 14275, a phosphodiesterase inhibitor were assessed in patients with coronary heart disease. 2 Left ventricular function was assessed in eight patients with acute myocardial infarction using the non-invasive measurement of systolic time intervals. 3 Twelve patients with angina pectoris were studied during diagnostic coronary arteriography. Left ventricular function was assessed using a high fidelity catheter tipped transducer in the left ventricle. 4 In both groups of patients U.K. 14275 infused intravenously in doses of 32, 64, 128 and 256 microgram kg-1 bodyweight min-1 enhanced the contractile state of the left ventricle without altering the heart rate.     

A prospective atmospheric emission inventory for cadmium--the European community as a study area

The quantities of cadmium emitted to the atmosphere from natural and human sources have been estimated for the member states of the European Community, allowing the construction of an atmospheric emission inventory for cadmium at the regional level. A survey of the available emission data was used to calculate an emission factor (g cadmium emitted tonne -1 material consumed or produced) for each source. This value was applied to the most recent consumption or production data for the region to obtain an annual discharge estimate. Predictions of future trends in cadmium emissions from human sources over the next two decades were based on economic forecasts for the process in question. The iron and steel industries and refuse incineration are the two largest sources of airborne cadmium in the region, followed by volcanic action and zinc production. It is forecast that there will be an increase in cadmium emissions over the next two decades due mainly to the iron and steel industries and zinc production. A comparison of the emission estimates obtained in this study with those given in previously published inventories reveal disparities in the source strengths for some processes. In particular, it would appear that cadmium emissions from coal combustion and non-ferrous metal production have been overestimated in some past studies.     

Phospholipid head-group conformations; intermolecular interactions and cholesterol effects

The predominant orientation of the phosphorylcholine polar head group in phosphatidylcholine and sphingomyelin bilayers and cholesterol perturbations of that orientation have been identified by exploiting the 31P (1H) nuclear Overhauser effect (NOE) in the 31P NMR spectra of phospholipid bilayers. In pure egg phosphatidylcholine bilayers, a NOE of 40% is observed. The magnitude of the NOE has been measured as a function of continuous-wave proton-decoupler frequency in order to identify the proton source of the NOE. In pure egg phosphatidylcholine bilayers, the maximum NOE occurs at the N-methyl proton resonance position of the choline moiety. In a modified phosphatidylcholine in which all the N-methyl protons were replaced by deuterium, the NOE arose from methylene protons next to the phosphate. In mixed systems of phosphatidylcholine and phosphatidylethanolamine, and phosphatidylcholine and diphosphatidylglycerol, both phospholipid resonances attained maximum NOE at the position of the N-methyl proton resonance of phosphatidylcholine. An analogous result was obtained with pure sphingomyelin. These results are explained by orienting the phosphorylcholine portion of the molecule parallel to the surface of the bilayer so that the positively charged N-methyl moiety is located close to the negatively charged phosphate on a neighboring phospholipid in an intermolecular interaction. Addition of cholesterol is shown to disrupt the intermolecular interaction in phosphatidylcholine bilayers.     

Genetic studies on chromosome 12 in late-onset Alzheimer disease

BACKGROUND: Gastroesophageal reflux (GER) appears to be related to laryngeal carcinoma. Little is known about GER and gastropharyngeal reflux (GPR) in the laryngectomized patient. Therefore, GER and GPR were studied in laryngectomized patients. METHODS: In 11 patients, 24-hour double-probe pH monitoring was performed in an ambulant setting. An optic fiberscope was used for the accurate positioning of the proximal probe in the upper esophageal sphincter. RESULTS: In 9 of 11 patients pathologic GPR was found. Four of these 9 patients had reflux in upright and supine position, 5 patients had reflux only in upright position. CONCLUSIONS: A high incidence of GPR in laryngectomized patients was found. These results raise the question whether all laryngectomized patients should be investigated for reflux and in the presence of pathologic reflux findings should be treated with reflux prophylaxis.