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A multigrid method for computing steady solutions of the compressible Navier–Stokes equations is described. The convection part of the equations is approximated by a simple low-order upwind-biased scheme employed for multigrid relaxation in combination with a higher order essentially non-oscillatory (ENO) scheme used to supply a defect correctionto the right-hand side of the discrete equations on the locally finest multigrid levels in a way ensuring the overall high accuracy of the solution. A damping technique is employed to stabilize and accelerate the defect-correction process.

We present an efficient parallelization strategy for speeding up the computation of a high-accuracy 3-dimensional serial Navier-Stokes solver that treats turbulent transonic high-Reynolds flows. The code solves the full compressible Navier-Stokes equations and is applicable to realistic large size aerodynamic configurations and as such requires huge computational resources in terms of computer memory and execution time. The solver can resolve the flow properly on relatively coarse grids. Since the serial code contains a complex infrastructure typical for industrial code (which ensures its flexibility and applicability to complex configurations), then the parallelization task is not straightforward. We get scalableimplementation on massively parallel machines by maintaining efficiency at a fixed value by simultaneously increasing the number of processors and the size of the problem. The 3-D Navier-Stokes solver was implemented on three MIMD message-passing multiprocessors (a 64-processors IBM SP2, a 20-processors MOSIX, and a 64-processors Origin 2000). The same code written with PVM and MPI software packages was executed on all the above distinct computational platforms. The examples in the paper demonstrate that we can achieve efficiency of about 60% for as many as 64 processors on Origin 2000 on a full-size 3-D aerodynamic problem which is solved on realistic computational grids.

If oesophagectomy is contra-indicated or dangerous, oesophageal bypass can restore the ability to swallow. It is not known if excluding the bypassed oesophagus by closing both ends will lead to serious complications. In this study we report on 89 patients who underwent bypass surgery for benign and malignant strictures of the oesophagus. The thoracic oesophagus was completely excluded in 51 patients and in 30 cases the bypass procedure was combined with distal oesophageal drainage. Gastro-oesophageal continuity was preserved in eight patients undergoing an extra-oesophageal colon bypass. The operative mortality was similar in the three groups. Neck abscesses, probably due to leakage from the upper end of the bypassed oesophagus, occurred in 17 per cent of patients with oesophageal exclusion and in 9 per cent of the remainder. Changes occurring in the bypassed oesophagus of 38 patients were monitored with computed axial tomography. Segmental, mucus-filled dilatations (mucocoeles) of the oesophagus were identified in 20 patients. In 19 patients these mucocoeles remained small and asymptomatic. One patient with achalasia developed an oesophago-airway fistula two years after operation. Provided both ends of the oesophagus are securely closed, oesophageal exclusion is not a dangerous manoeuvre in patients undergoing bypass surgery for locally invasive tumours or corrosive injuries of the oesophagus.

In using radionuclide imaging of the inferior vena cava RIVC to investigate the prevalence of membranous obstruction of the inferior vena cava IVC in patients with hepatocellular carcinoma, it was necessary first to determine if this technique would distinguish membranous obstruction of the IVC both from other causes of IVC obstruction likely to be encountered in these patients and from the picture obtained with severe ascites. RIVC readily distinguished an obstructed from a normally patent IVC. However, membranous obstruction of the IVC could not in most instances be differentiated from extrinsic compression of the IVC by an enlarged tumourous liver, occlusion of the lumen of the IVC by tumour, or the effect of severe ascites. In a proportion of the patients with membranous obstruction of the IVC, flow of the radionuclide through large superficial collateral vessels was seen, enabling this diagnosis to be made with confidence. Thus, if RIVC shows the IVC to be obstructed or if severe ascites is present, contrast venography will usually be necessary to determine the nature of the obstructing lesion.

Summary: Lung injury was induced in young rats by a continuous infusion of hypoxanthine intravenously and breathing 100% oxygen for 48 h (group 1). Control animals were rats infused glucose and breathing 100% oxygen (group 2), rats infused hypoxanthine in room air (group 3), and untreated rats (group 4). In group 1 rats interstitial and alveolar edema was found with a tendency toward marked margination of polymorphonuclear neutrophils in small vessels (P < 0.025 compared with group 2). The main elastase inhibitor alpha,-antitrypsin (α-l-PI) was significantly elevated in group 1; 2-, 3− and 5-fold, respectively, when compared with groups 2, 3, and 4. The surfactant phopholipids from alveolar lavage were normal in all groups. The protein-rich fraction of the lavage fluid from group 1 rats inactivated, however, the surface properties of lung surfactant. Minimum surface tension in group 1 rats was 14.5 dyn/cm compared with 7.0 dyn/cm in group 2, 2.9 dyn/cm in group 3 and 3.5 dyn/cm in group 4 (P < 0.05, group 1 and 2 versus 4). We conclude that the combination of hypoxanthine and high levels of oxygen causes lung injury, possibly via free oxygen radicals. We discuss the possibility that these findings demonstrate a basic pathogenetic mechanism for the hypoxic-hyperoxic insult and can contribute to the understanding of pathogenesis of a variety of diseases both in pediatrics and adult medicine.

Abstract: The dielectric permittivity and conductivity of freshly excised dog skeletal muscle were measured at frequencies between 20 Hz and 1 MHz, with the tissue samples oriented either parallel or perpendicular to the applied electric field. At frequencies below 100 kHz a four-electrode technique was employed; at frequencies above 100 kHz a conventional two-electrode technique was used in conjunction with a commercial admittance bridge. All measurements were performed with the tissue sample at body temperature. Over the entire frequency range of the study, the dielectric properties of the muscle were found to be significantly anisotropic. At audio frequencies, the conductivity of the muscle measured in a direction parallel to the fibre orientation was typically found to be ten times higher than that measured perpendicular to the fibre axis; at frequencies approaching 1 MHz the conductivities measured in both directions approached a common value, near 8 ms cm−1. The dielectric permittivity in both orientations is strongly dependent on frequency. These data are analysed using the suspension equation, and comments are made on the mechanisms that are responsible for the observed properties. In an Appendix these results are related to some of the very early work on the subject.

Ohne Zusammenfassung:

Rabbits were inoculated with the C.P.M. strain of myxoma virus and the resulting subcutaneous tumors were fixed, embedded, and sectioned for observation with the electron microscope. Both round cells and the typical stellate myxomatous cells were observed in addition to changes in the collagen pattern at the intercellular spaces. The cytoplasm of the cells showed a great number of bodies of varying size and density, the largest of them having the size and other characteristics of the elementary bodies of the virus. Some of the bodies showed an internal structure, being formed by the tight clumping of small dense particles. Distribution curves of the diameter of the elementary bodies and of the smaller internal particles are presented. The morphological problems involved in the virus-host cell relationship are discussed in the case of the myxoma virus.

Guinea pigs were inoculated with the Vallée O type strain of the virus of foot-and-mouth disease. 42 to 48 hours after inoculation red blood cells washed in saline were found to be infective for normal guinea pigs suggesting that erythrocytes carry virus entities at the height of generalization of the disease. This infection is no longer obtained at 92 hours after inoculation when general symptoms of the disease decline. A replica-transfer technique was developed with which hemolyzed blood smears could be observed under the electron microscope. By direct examination and also shadow-casting with palladium, normal red cell membranes show only a very fine structure on the surface. Rounded masses of high electron density appear in the ghosts between 24 and 72 hours after inoculation with virus. The number and particularly the density of these masses tend to increase from 24 to 42 and 72 hours. In some cases they are disposed preferentially in single lines forming ring figures; in other cases they are distributed at random. At 42 hours after inoculation it was possible to detect dense particles of 20 to 70 mµ. within the masses. Measurements of 100 masses at 72 hours gave results ranging from 116 to 437 mµ with a mean diameter of 246 mµ. Results based on 105 electron micrographs and on thousands of cells demonstrate that practically all red cell membranes contained dense masses 24 to 72 hours after inoculation. 92 hours after inoculation, coinciding with the disappearance of infectivity of the erythrocytes, the masses could no longer be seen and the membranes looked entirely normal. Although the facts reported here may be suggestive of a relationship between the dense masses within the red cell membranes and the presence of virus entities in washed erythrocytes, no definite interpretation of these findings is postulated at present.

BECK, McKhann and Belnap1 made a noteworthy attempt to increase the vascularization of the brain in patients with mental retardation, convulsive disorders and various types of sensory and motor defects. These investigators established an arteriovenous fistula between the common carotid artery and the internal jugular vein, thereby converting the vein into an arterial channel. They chose the right side for the anastomosis, because a colored mixture injected into the right internal jugular vein in cadavers "filled the superior sagittal sinus and all of its visible branches." They concluded:... The right jugular vein drains the cerebral cortex and that [blood] reaching the left jugular comes from the deeper portions and cerebellum.... Operation upon the right side would contribute the majority of blood to the cortex and also significant amounts to the deep circulation.They operated on 11 patients and reported their results in four, stating that "although the postoperative follow-up

The fate of inhaled Fe259O3 in rats at short intervals of time after inhalation has been studied primarily to evaluate this material for cytokinetic studies of the lung. Following “nose only” types of exposures, complete analyses were performed on tissues and excreta. Upper and lower respiratory tract retention has been presented in two ways. The differences in clearance rates thus obtained are due to a significant early absorption or transport as reflected in carcass values. Suitability of Fe2O3 for cell studies is concluded to be adequate, but further emphasis is given to the need for characterization of this aerosol, particularly for solubility and ultrafiltrability in other test uses.

Blood and plasma smears of mice inoculated with two leukemic lines were studied under the electron microscope. In 15 mice of the AKR strain and in two C58 mice inoculated with the Hch leukemia line of the Instituto de Biología of Chile (372 to 382 transfers), dense submicroscopic particles were found in the blood plasma. In some cases isolated particles or clumps of them were found adsorbed on the red cell membranes. The particle size ranged between 19 and 58 mµ, with a large peak at 38 mµ. The survival time of the inoculated animals was of 5 days and the submicroscopic particles were constantly found between the 3rd and 5th day. Similar dense submicroscopic particles were found in blood plasma smears of three C58 mice at the 16th day after inoculation with the Ich leukemia line (86th transfer). The probable significance of these particles is discussed on the basis of the literature regarding the etiology of mouse leukemia.

1. Erythrocyte membranes from calves infected with Anaplasma marginaliswere studied under the electron microscope. The classical single marginal body of the parasite appears to be constituted of a central undivided mass and peripheral elementary bodies of high electron density, 170 to 220 mμ in diameter. In some cases the whole mass of the parasite is divided into these small submicroscopic bodies. In other erythrocytes the elementary bodies are dispersed and have a tendency to grow up. Distribution curves on measurements of 119 elementary bodies are presented. 2. The presence of the submicroscopic forms of the parasite is discussed in the light of the clinical and hematological evolution of the disease, the multiplication and the probable life-cycle of the parasite within the blood stream.

Stable beam transport may be the limiting factor in the development of a new generation of high current linear induction accelerators. In this paper we analyze several important beam stability topics, including radial oscillations induced by an accelerating gap, the diocotron, resistive wall, and cyclotron maser instabilities, and the transverse beam breakup and image displacement instabilities. At present image displacement appears to represent the most serious limitation to high current beam transport in linear accelerator structures.

Lung injury was induced in young rats by a continuous infusion of hypoxanthine intravenously and breathing 100 oxygen for 48 h (group 1). Control animals were rats infused glucose and breathing 100 oxygen (group 2), rats infused hypoxanthine in room air (group 3), and untreated rats (group 4). In group 1 rats interstitial and alveolar edema was found with a tendency toward marked margination of polymorphonuclear neutrophils in small vessels (P< 0.025 compared with group 2). The main elastase inhibitor alpha,-antitrypsin (α-l-PI) was significantly elevated in group 1; 2-, 3− and 5-fold, respectively, when compared with groups 2, 3, and 4. The surfactant phopholipids from alveolar lavage were normal in all groups. The protein-rich fraction of the lavage fluid from group 1 rats inactivated, however, the surface properties of lung surfactant. Minimum surface tension in group 1 rats was 14.5 dyn/cm compared with 7.0 dyn/cm in group 2, 2.9 dyn/cm in group 3 and 3.5 dyn/cm in group 4 (P < 0.05, group 1 and 2 versus4). We conclude that the combination of hypoxanthine and high levels of oxygen causes lung injury, possibly via free oxygen radicals. We discuss the possibility that these findings demonstrate a basic pathogenetic mechanism for the hypoxic-hyperoxic insult and can contribute to the understanding of pathogenesis of a variety of diseases both in pediatrics and adult medicine.

The computed tomographic (CT) findings of malakoplakia of the bladder are presented. Although the CT findings were not considered specific for this condition, the presence of a solid bladder mass with or without extension beyond the confines of the bladder in a young woman with urinary tract infection should suggest the possibility of this diagnosis.

The propensity of pancreatic fluid collections to dissect along established tissue planes is well known. Pancreatic pseudocysts have been described in virtually every organ in the body but particular attention has been paid to findings of pseudocysts in the anterior pararenal space, the lesser sac, the spleen, the mediastinum and the perirenal space (Asokan et al, 1977; Warshaw etal, 1972; McAllen, 1977). More recently, the finding of pseudocysts in the left lobe of the liver has been described (Siegelman et al, 1980). We recently had the opportunity of studying two patients with pseudocysts involving the left lobe of the liver.A 55-year-old man, with a heavy alcoholic history, was admitted with sharp chest pain radiating to the left side of the abdomen, vomiting, diarrhoea and shortness of breath. Physical examination revealed a distended abdomen with a 5–6 cm tender hepatomegaly. There was generalised abdominal tenderness and guarding, with an impression of a vague mass in the left hypochondrium.The haemoglobin was 11.7 g/dl, white blood cell count 16 100 mm-3, serum amylase 132U and erythrocyte sedimentation rate 90mm/h-1. The results of liver function tests were within normal limits.Abdominal X ray revealed numerous fluid levels and free fluid in the abdomen. Chest X ray showed hyperinflated lung fields and a left pleural effusion. Abdominal sonography revealed ascites and two large cystic collections with debris within them; one was adjacent to, and appeared to involve, the left lobe of the liver; the other was in the lesser sac area.

THIS communication outlines a probability model which seems to provide an adequate basis for making predictions concerning the occurrence of largest earthquake magnitudes over time: (a) The number of earthquakes in a year is a Poisson random variable with mean α; (b) X, the earthquake magnitude, is a random variable distributed with cumulative distribution function:

A method is discussed for determining the parameters of a nonlinear device by measurement of the harmonics generated in the output when a sinusoidal wave is applied at the input. Formulas are developed, in terms of the measured quantities, for determining the coefficients of the power series describing the input-output characteristic and the coefficients of the Fourier series giving the harmonic conversion transconductance.

Ohne Zusammenfassung:

This collection of chapters on the pathology, diagnosis, and treatment of central nervous system (CNS) tumors is directed toward a team approach in the radiotherapeutic management of some of the complicated problems that these patients have. Each section is written with the expertise of long experience. However, the volume itself has the disadvantage of discontinuity, almost inevitable in most works by multiple authors. This is offset in great measure by the precise condensation of information and the concise summarization of today's radiation therapeutic method and some of the results.A brief overview of the diagnosis of CNS tumors includes radiologic, radionuclide, ultrasound, and electroencephalographic methods. Computerized axial tomography is mentioned briefly, undoubtedly reflecting the state of the art at the time the chapter on radiodiagnosis was written. The physiology and clinical implications of increased intracranial pressure are well considered. While there is no attempt to go into the details