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This work describes the application of a hybrid two-step enantioselective separation process. As a first step, pertraction using supported liquid membranes provides an initial enrichment, while the following preferential crystallization delivers the enantiopure crystals as final product. Mandelic acid in water was studied as a model system. Using a suitable chiral selector, pertraction provides enrichments exceeding 10% and reaching up to 20% in the permeate phase, which was sufficient to allow for subsequent selective preferential crystallization. Based on the individual performances of pertraction and crystallization, overall yields and productivities are estimated. The calculated productivities are compared with values achievable in alternatively applicable chromatographic separation processes using chiral stationary phases. The realized hybrid pertraction-crystallization process is in its present state for the example considered still inferior to preparative chromatography. Strategies for further improvement are suggested.

We have studied the interaction of carbon monoxide with a Re(10-10) surface between 150 and 800 K by means of low-energy electron diffraction (LEED), temperature-programmed thermal desorption, and ...

The aim of this study was to analyze the color Doppler sonographic findings in primary epiploic appendagitis. Color Doppler sonographic findings of ten patients with primary epiploic appendagitis were reviewed. The following sonographic features were analyzed: identification of a mass adjacent to the colonic wall; identification of spotty color areas with arterial flow in this mass and detection of abnormalities of the colonic wall adjacent to the infiltrated fatty tissue. A well-delineated hyperechoic mass adjacent to the colonic wall was detected in each patient with sonography. No colonic wall abnormalities were observed nor color Doppler signal in and around the hyperechoic area. Absence of flow at color Doppler sonography is an additional feature of epiploic appendagitis.

Event-related brain potentials were recorded while subjects performed either a rotation or a size scaling transformation of a mental image. Images had to be rotated 0 degrees, 60 degrees, or 120 degrees or their size had to be enlarged by factors of 1:1, 1:3, or 1:5. Both tasks were accompanied by pronounced negative slow potentials, which extended over several seconds. The relative maximum of these shifts emerged at central to occipital leads. Over the occipital cortex, the negative potential had a similar amplitude level in all conditions and both tasks. However, at parietal and central areas, the negative slow wave changed in relation to the difficulty of the task. The amplitude increased with increasing rotation demands and if the scaling operation required an exact computation of the coordinates of the image. None of these effects could be attributed to an inverse change of P300.

We report the case of an 82-year-old female presenting with acute epigastric abdominal pain after traumatic blow on the epigastrum. High-resolution multimodal imaging comprising Ultrasound, CT and MR, correlation with laboratory blood analyses and a 6 months CT follow-up allowed us to make a definite diagnosis of traumatic heterotopic pancreatitis. This case emphasizes the relevance of a well-targeted high-definition ultrasound study in the following of the first imaging modality.

We have deposited Au films in ultra-high vacuum onto a rhenium ([Formula: see text]) surface in submonolayer and multilayer concentrations and studied them by means of low- and medium-energy electron diffraction in the temperature range between 300 and 800 K. In the submonolayer range, Au forms several low-energy electron diffraction (LEED) phases, namely, a (1 × 3), a (1 × 4), a (1 × 5) and a (1 × 6) phase, consisting of one-dimensionally ordered Au chains in the [[Formula: see text]] direction, until the formation of a complete pseudomorphic monolayer is indicated by a (1 × 1) LEED phase. In the multilayer regime, a (1 × 8) LEED phase appears over a surprisingly wide coverage range from about two to at least eight monolayers, which we interpret as a hexagonal uniaxially compressed reconstructed Au overlayer on pseudomorphically grown hexagonal close-packed gold layers. In order to get access to absolute Au coverages, we have performed LEED (I,V) measurements and carried out a LEED structure determination for the (1 × 1) phase. We propose the formation of a full Au monolayer in which both the Re trough and top-row sites are being covered by Au atoms. The data are discussed and compared with those from previous studies on related systems.

Septic endarteritis complicating arterial cannulation is an exceptional condition. The authors report a quick and feasible surgical procedure to reconstruct a femoral bifurcation with reversed bifurcated saphenous vein graft.

A case of leiomyosarcoma of the superficial femoral vein detected in the follow-up of a non resolving deep venous thrombosis is presented. A short review of the literature focused on this unusual entity is presented.

Pancreaticopleural fistula secondary to chronic pancreatitis is a rare cause of recurrent pleural effusion. The demonstration of the fistula with endoscopic retrograde pancreatography and CT is invasive or limited. We report in two patients the use of magnetic resonance pancreatography as a noninvasive alternative to endoscopic retrograde pancreatography for the diagnosis of pancreaticopleural fistula.

We describe a case of pancreatic cystosis in an 18-year-old man suffering from cystic fibrosis, who presented with acute epigastric pain. Ultrasound and computed tomographic studies revealed multiple pancreatic cysts of various size, measuring up to 5 cm. Pancreatic macrocystosis is an extremely rare manifestation in cystic fibrosis.

The high diagnostic ability of sonography for the solid organs of the upper abdomen and the biliary and genitourinary tract is well established. The gut on the other hand has been more or less ignored by many sonographers in routine abdominal screening and evaluation of the acute abdomen. This is regrettable because sonography, like CT, is an excellent modality for assessing mural abnormalities of various origin (i.e. neoplastic, inflammatory, ischemic or hemorrhagic), as well as possible involvement of the adjacent soft tissues and solid organs. Considerable sonographic skill and "tenacity" and an adequate equipment are however indispensable to achieve high diagnostic reliability in the detection and interpretation of abnormalities of the G-I tract. Our own and other's experience suggest that the time devoted to sonographic screening of the gut is very worthwhile especially in acute clinical conditions. Acute appendicitis is one of the typical examples where sonography has found widespread acceptance. This article reviews the application of graded compression sonography in the evaluation of appendicitis, for using on technique, diagnostic criteria, and differential diagnosis.

We have deposited Au films in ultra-high vacuum onto a rhenium () surface in submonolayer and multilayer concentrations and studied them by means of low- and medium-energy electron diffraction in the temperature range between 300 and 800 K. In the submonolayer range, Au forms several low-energy electron diffraction (LEED) phases, namely, a (1 × 3), a (1 × 4), a (1 × 5) and a (1 × 6) phase, consisting of one-dimensionally ordered Au chains in the [] direction, until the formation of a complete pseudomorphic monolayer is indicated by a (1 × 1) LEED phase. In the multilayer regime, a (1 × 8) LEED phase appears over a surprisingly wide coverage range from about two to at least eight monolayers, which we interpret as a hexagonal uniaxially compressed reconstructed Au overlayer on pseudomorphically grown hexagonal close-packed gold layers. In order to get access to absolute Au coverages, we have performed LEED (I,V) measurements and carried out a LEED structure determination for the (1 × 1) phase. We propose the formation of a full Au monolayer in which both the Re trough and top-row sites are being covered by Au atoms. The data are discussed and compared with those from previous studies on related systems.

Seventeen kidneys removed from patients with renal carcinoma were submitted to ex vivo ultrasonography and then to serial pathological examination in an attempt to detect secondary tumours in apparently normal tissue. Ex vivo ultrasonography failed to reveal further tumours, but 2 lesions measuring 5 and 8 mm were found on pathological examination. These preliminary data suggest that intra-operative ultrasonography may be of little value in detecting secondary tumours in conservative surgery for renal carcinoma.

Liver ultrasound was prospectively evaluated in 104 subjects who underwent liver biopsy, including 24 patients without evidence of liver disease (controls), and 80 with a broad spectrum of liver pathology. Ultrasonography was very specific (100%) and moderately sensitive (70%) in the detection of liver pathology, and hepatic neoplasms, steatosis, and fibrosis were detected by ultrasound in 80%, 80%, and 67% of cases respectively. In addition, ultrasonography diagnosed other pathologies--mainly biliary tract disease and abdominal neoplasms--in 26% of the patients.

A description of Monsanto's FLOWTRAN (Flowsheet Translator) system is given. A sample chemical process is first used to illustrate the system. Then the manner in which FLOWTRAN's design addresses some of the commonly encountered problems in chemical process simulations is discussed. Finally some reactions of industrial and academic users to the system are indicated.

A differential type of flow reactor, 0.25-in. I.D., was used to study the kinetics of the hydrogenation of ethylene on an alumina-supported nickel catalyst. This is apparently the first investigation made above atmospheric pressures. Data were obtained from 14.7 to 70 1b./sq. in. abs. and feed compositions from 40 to 90 mole % hydrogen. Measurements at temperatures from 30° to 80°C. indicated an apparent activation energy of 11,600 cal./g.-mole. It was found that the activity of the catalytic surface was reduced by exposure to ethylene, or mixtures containing an excess of ethylene, owing to the formation of acetylene residues. Pretreatment of the catalyst at temperatures of 170°C. with mixtures of ethylene and hydrogen stabilized the catalyst so that reliable rate data could be obtained. The rate measurements at 70°C. were correlated by an equation. While the mechanism of the reaction cannot be determined from the data, the rate expression and other kinetic studies suggest a process in which hydrogen is adsorbed on the small fraction of the surface not occupied by acetylenic residues and the reaction takes place between this adsorbed hydrogen and ethylene in the gas phase.

Two digital computer routines were developed to process flame speed data resulting from the burning of compounds in air and oxygen, and to correlate particular structural configuration with flame speed. In both routines a high degree of flexibility has been incorporated to assure efficient utilization under several forseeable circumstances. The first routine, FSC, processes the raw experimental data to obtain flame speeds, equivalence ratios, and the equivalence ratio at the maximum flame speed. This information is stored on a master magnetic tape for subsequent calculations. The second routine, FSR, permits sel ion of specific data groups from the master tape for analysis. A linear model was chosen for the correlation.