Synthesis and properties of amphiphilic “dumbbell”-shaped grafted block copolymers, 1. Anionic synthesis via a polyfunctional initiator

1994

Two poly(ethylene oxide) stars linked by a long polystyrene chain represent a novel amphiphilic architecture (dumbbell), which is available by anionic grafting of ethylene oxide from a hydroxylated polybutadiene-block-polystyrene-block-polybutadiene triblock copolymer. The short butadiene end-blocks (DPB = 36) of a BSB triblock copolymer with a long styrene middle block (DPS = 650) was first modified by hydroboration and oxidation. A multifunctional alkoxide initiator is thus prepared by titration of the hydroxyl groups of the “polybutadiene” end-block with cumylpotassium. Gelation and precipitation of the polyfunctional initiator in THF could be avoided by complexing the cation (K+) with a…

VIGIL System: A Computer Vision-Based AID System. Evaluation in a Ring Motorway Section in Madrid

1994

Abstract The VIGIL system is an Automatic Incident and Congestion Detection System based on computer vision technology tor motorway applications. VIGIL is constituted by two main modules, the Local Sensor Module and the Central System module. The objective of this paper is to describe the VIGIL Central System functions, mainly the alarm filtering and management capabilities, and to present the field trial currently carried out in Madrid within the ARTIS project (Advanced RTI in Spain) supported by the Tranport Telematic Programme of the EC.

Block and graft copolymers of 2-oxazolines

1994

The cationic ring-opening polymerization of 2-oxazolines is known to be initiated by alkyl halides, Lewis acids and esters of strong acids. The polymerization proceeds by a living mechanism. Numerous block and graft copolymers have already been described. Recently it was found that chloroformates (R-O-CO-CI) are also useful initiators. The mechanism of the initiation and propagation is discussed. This type of initiators allows the synthesis of different novel two-block and three-block copolymers, star-shape polymers, and a graft copolymer with a polyvinylacetate backbone.

Photoconductivity of Poly(Arylenevinylene)S and Poly(Hetarylenevinylene)S

1994

Abstract The intramolecular condensation of aromatic Schiff bases leads under strong alkaline conditions to the poly(arylenevinylene)s and poly(hetarylenevi-nylene)s A - H. Due to the extreme stereoselectivity the resulting products are rigid, (E)-configurated polymers. The broad band gap of the unsubstituted intrinsic insulators is decreased by alkoxy substituents. Investigations of the photoconductivity and the photoreactivity, as well as of the AC-conductivity of some undoped, doped and quaternized systems are performed.

Phase partitioning of aerosol particles in clouds at Kleiner Feldberg

1994

The partitioning of aerosol particles between cloud droplets and interstitial air by number and volume was determined both in terms of an integral value and as a function of size for clouds on Mt. Kleiner Feldberg (825 m asl), in the Taunus Mountains north-west of Frankfurt am Main, Germany. Differences in the integral values and the size dependent partitioning between two periods during the campaign were observed. Higher number and volume concentrations of aerosol particles in the accumulation mode were observed during Period II compared to Period I. In Period I on average 87 ± 11% (±one standard deviation) and 73 ± 7% of the accumulation mode volume and number were incorporated into cloud…

Quantitative investigations on the human entorhinal area: left-right asymmetry and age-related changes

1994

The total nerve cell numbers in the right and in the left human entorhinal areas have been calculated by volume estimations with the Cavalieri principle and by cell density determinations with the optical disector. Thick gallocyanin-stained serial frozen sections through the parahippocampal gyrus of 22 human subjects (10 female, 12 male) ranging from 18 to 86 years were analysed. The laminar composition of gallocyanin (Nissl)-stained sections could easily be compared with Braak's (1972, 1980) pigmentoarchitectonic study, and Braak's nomenclature of the entorhinal laminas was adopted. Cell-sparse laminae dissecantes can more clearly be distinguished in Nissl than in aldehydefuchsin preparati…

Numerical Taxonomy of Vibrionaceae Isolated from Oysters and Seawater Along an Annual Cycle

1994

Summary A numerical taxonomic study on Gram negative heterotrophic facultative anaerobic bacteria isolated from marine samples (oysters and seawater of Western Mediterranean Sea) was performed. Three hundred sixty eight strains, including reference strains of most species of the Vibrionaceae , were characterized (96 tests per strain). Cluster analysis of similarity matrices obtained with S SM and S J coefficients was performed and S J -based tree and 0.75 S level selected for definition of phena. Larger phena corresponded to non-luminescent Vibrio splendidus biotype 1 and V. harveyi . The species V. tubiashii (an oyster larvae pathogen), V. pelagius, V. mediterranei, V. orientalis and Photo…

Activity and immunohistochemistry of DT-diaphorase in hamster and human kidney tumours.

1994

We have studied the biochemical and immunohistochemical changes of DT-diaphorase in diethylstilbestrol (DES)-induced hamster kidney tumours and human biopsies from normal kidneys and renal clear cell carcinoma. The activities of primary and secondary antioxidants in these hamster and human tissues are also reported. DT-diaphorase is decreased in the different subcellular fractions of hamster and human tissues. In hamster kidney the activities of the one-electron quinone reductases show a nearly two-fold increase. Immunohistochemical findings confirm the decrease in DT-diaphorase in hamster and human tissues. This image is of special interest in the case of nephroblastoma (Wilms' tumour), si…

Reaction time paradigms in subjects at risk for schizophrenia.

1994

Abstract Deviant response patterns in experimental reaction time paradigms in schizophrenic probands are well documented. Although simple reaction times are strongly influenced by the current psychopathological status of the proband (e.g. florid psychotic patients versus remitted patients) these influences are less clear for measures obtained from more complex reaction time paradigms. These include the crossover paradigm (reaction time to stimuli presented after constant preparatory intervals in comparison to reaction time to stimuli presented after irregular preparatory intervals) and the modality shift paradigm (reaction time to a stimulus (light or tone) when the modality of the stimulus…

Monitoring of the pesticide levels in natural waters of the Valencia Community (Spain)

1994

SCREENING OF CHEMICAL SPILL RISKS TO MUNICIPAL SEWAGE TREA TMENT PLANTS

1994

Seven operational mishaps were specified on the basis of a questionnaire on wastewater treatment plants, some of them large. In this study a process was developed for screening the chemical spill risks to municipal biological sewage treatment plant. Data on wastewater treatment processes, potential spill sources and chemical properties were combined to determine the threshold chemical quantities which may inhibit the removal of carbonaceous material, prevent nitrification and methanogenesis, cause sludge contamination or lead to the aeration capacity being exceeded. Two sewage treatment plants and eleven industrial sites were chosen for field studies. The influence of spill duration and mai…

In-witro-NMR-Spektroskopie an gesunden, mastopathisch veränderten und karzinomatös befallenen Brustdrüsen-gewebsproben, korreliert mit histologischen…

1994

Es wurden bei 57 Patientinnen mit klinischem Verdacht auf Mammakarzinom 121 Gewebeproben entnommen und mittels der 1H-NMR-Spektroskopie bei 300 MHz in vitro nach Korrelation mit histologischen Befunden untersucht. Im interessanten Spektralbereich zwischen 2,7 und 4,1 ppm wurden starke Signale beobachtet, die Fett, (Phosphoryl-)Cholin, Kreatin(-phosphat) sowie Karnitin zugeordnet wurden. Weiterhin konnten mit hoher Regelmasigkeit 8 schwachere, zum Teil uberlappende Signale der Substanzen Glukose, Glyzin, Threonin, Serin, Inositol und Saccharose nachgewiesen werden. Hierbei wurden Linienintensitaten uber ein iteratives Fitprogramm bestimmt. Uber deren Quotienten konnten unterschiedliche Geweb…

Instrument intercomparison study on cloud droplet size distribution measurements: Holography vs. laser optical particle counter

1994

During the EUROTRAC Ground Based Cloud Experiment (GCE) 1990, a newly developed HODAR (Holographic Droplet and Aerosol Recording) was operated for the first time to measure cloud droplet size distributions by recording Fraunhofer in-line holograms of small cloud sample volumes in situ and analyzing the holographic images in the laboratory.

Sesquiterpene Lactones fromCentaurea paui

1994

Abstract A new elemanolide and two new heliangolides as well as (2R,3R)-(+)-3-hydroxy-2-methyl-butyrolactone have been isolated from Centaurea paui. The structures were elucidated by high field NMR techniques and chemical transformation.

Granulomatous slack skin: report of a case associated with Hodgkin's disease and a review of the literature.

1994

We report a case of granulomatous slack skin (GSS) associated with Hodgkin's disease, and review the literature on this entity. GSS, a variant of cutaneous T-cell lymphoma, clinically presents with erythematous patches in the flexures, which gradually transform into bulky, pendulous areas of skin. Histology shows an elastolytic granulomatous infiltrate, with atypical lymphoid cells, and occasional epidermotropism. As far as we are aware, 10 cases of GSS, including our patient, have been reported in detail. The male:female ratio of these cases is 9:1, and the age range 15-51 years. Five cases were associated with Hodgkin's disease, one with small lymphocytic lymphoma, and one developed cutan…

The synthesis and X-ray study of (η6-benzamide)- and (η6-phenylacetamide)tricarbonyl chromium complexes. Structural effects of the substituent

1994

(η6-Benzamide)tricarbonylchromium and tricarbonyl(η6-phenylacetamide)chromium (1 and 2) have been synthesized from the corresponding amides and chromium hexacarbonyl. Decalin, a mixture of decalin and butyl acetate, and neat butyl acetate have been used as the reaction media. The first system gave best yields. Both amide complexes form adducts with non-complexed molecules of the type [(CO3)CrL] · L through hydrogen bonds, suggested on the basis of 1H and 13C NMR spectroscopy. Similar associations by hydrogen bonds exist in the solid state structure of 3 and 4. The π-donor-acceptor abilities of the substituents on the rings are discussed on the basis of geometrical parameters and 13C NMR dat…

Economical device for measuring thickness of a thin polymer film

1994

An inexpensive device (about $2K) for thickness measurements of thin (<1 μm) polymer films has been constructed. The homogeneous film is placed on a bulk substrate and three semiconductor lasers of different wavelengths are used to measure the reflectances at normal incidence. The thickness can be deduced with typically 4–8 nm uncertainty.

A mesoscopic approach to radiation-induced defect aggregation in alkali halides stimulated by the elastic interaction of mobile Frenkel defects

1994

The radiation-induced aggregation of Frenkel defects in alkali halides is studied in terms of a mesoscopic approach. The asymmetry in elastic interactions between mobile interstitials (I–I) and bet...

Mott scattering as a probe of long range QCD effects

1994

We investigate the possibility of using the Mott scattering between identical nuclei to assess the existence of long range QCD effects, e.g., a color van der Waals interaction, as suggested recently. We show that the inclusion of atomic effects is very important and should be considered in order to extract limits on the strength of the color van der Waals force. We compare our calculations with the analysis of a recent heavy ion experiment.

Prevalence and causes of blindness and low vision in the Casteldaccia Eye Study.

1994

In a population-based survey performed on the middle-aged and elderly population of Casteldaccia, Sicily, we found that the prevalence of blindness was 0.47% and the prevalence of low vision 1.22%. Unilateral blindness affected 2.81% of the population and unilateral low vision 4.12%. Visual impairment was much more frequently seen in subjects aged 70 years or more than in younger persons. The main cause of visual impairment was cataract, followed by amblyopia, which was responsible for many cases of unilateral low vision.

The influence of leflunomide on cell cycle, IL-2-receptor (IL-2-R) and its gene expression

1994

Leflunomide is a novel immunomodulatory drug shown to be very effective in animal models of autoimmune diseases and transplantation rejection, as well as in human rheumatoid arthritis. Leflunomide's main metabolite, A77 1726, has been shown to be reversibly antiproliferativein vitro. Pursuing this, we performed cell cycle analysis by flow cytometry of a B-cell lymphoma line and found that at concentrations >2.5 μM cells accumulated in the early S-phase. In order to determine A77 1726's effects on cell activation, human peripheral blood lymphocytes (PBL) were cultured in the presence of PHA or OKT 3 antibody. Flow cytometric evaluation of IL-2 and transferrin receptor expression exhibited a …

Transvaskuläre Fensterung eines dissektierenden Aortenaneurysmas

1994

The Kleiner Feldberg Cloud Experiment 1990. An overview

1994

An overview is given of the Kleiner Feldberg cloud experiment performed from 27 October until 13 November 1990. The experiment was carried out by numerous European research groups as a joint effort within the EUROTRAC-GCE project in order to study the interaction of cloud droplets with atmospheric trace constituents. After a description of the observational site and the measurements which were performed, the general cloud formation mechanisms encountered during the experiment are discussed. Special attention is given here to the process of moist adiabatic lifting. Furthermore, an overview is given regarding the pollutant levels in the gas phase, the particulate and the liquid phase, and som…

Detection of vitellogenin in a subpopulation of sea urchin coelomocytes.

1994

Sea urchin vitellogenin is a high molecular weight glycoprotein, which is the precursor of the major yolk protein present in the unfertilized egg. Vitellogenin processing into the major yolk protein and its further enzymatic cleavage during sea urchin embryonic development, has been extensively described, and the adhesive properties of the processed molecule have been studied. The function of vitellogenin in the adult, where it has been found in the coelomic fluid of both male and female individuals, is still unknown, although its role on promoting the adhesion of embryonic cells has been shown. In this report we describe the detection of vitellogenin in lysates of whole circulating coelomo…

Su di un caso di Schwannoma primitivo intraorbitario

1994

Gli Schwannomi costituiscono il 6,8% dei tumori intracranici ed originano solitamente dai nervi sensitivi, con particolare predilezione per il V e VIII nervo cranico. Uno schwannoma a partenza da un nervo oculomotore costituisce invece una evenienza piuttosto rara, e solo 17 casi di s. del III n.c. sono stati documentati in letteratura. Sono da considerare ancora più rari gli schwannomi ad esclusiva localizzazione intraorbitaria (1–5, 7% dei tumori orbitari). Solitamente tipico dell'uomo adulto, con l'eccezione dei soggetti affetti da Neurofibromatosi di tipo 2, lo schwannoma orbitario esordisce solitamente come un processo espansivo a lento accrescimento, determinante diplopia, esoftalmo …

The Body in Tourism

1994

Oral chloral hydrate provides effective and safe sedation in paediatric magnetic resonance imaging.

1994

SUMMARY Sedation is routinely required for successful Magnetic Resonance imaging in infants and children. Five hundred and ninety-six paediatric patients (270 female and 326 male, age (mean±SD) 41±30 months and weight 14.8±6.5 kg) entered an open, non-comparative, prospective study to assess oral chloral hydrate sedation in a large and homogeneous paediatric population undergoing Magnetic Resonance imaging. Chloral hydrate syrup 70 mg/ml was administered 20–40 min prior to the procedure. Effective sedation was reached in 94.1% with a total dose (mean±SEM) of 68±1 mg/kg (range 20–170 mg/kg). Statistical analysis of sedation failures vs. successful examinations after the total dose showed sig…

Pressure Dependence of Positron Annihilation in Si

1994

The pressure dependence of the electron-positron and the electron-electron momentum densities in silicon are studied. The observations that the electron-positron momentum density increases more rapidly with pressure than the electron-electron momentum density alone is explained in terms of increased positron penetration into the ion cores. The computational technique used here is based on the independent-particle model (IPM) coupled with the use of the electron pseudo-wave functions.

Separation of polycyclic aromatic hydrocarbons under isocratic conditions by a column switching technique

1994

A simple and efficient method of separating a 20-component PAH-mixture (RSM 1647 standard mixture +benzene, toluene, perylene and coronene) by RP-HPLC is described. Separation was by using two Superspher-100 RP-18 cartridges thermostatted at different temperatures under isocratic conditions with water-acetonitrile eluent. The analysis time with complete resolution of all components can be reduced to 15 min.

Kinetics and mechanism of group transfer polymerization of N-butyl acrylate catalyzed by Hgl2 /(CH3 )3 Sil in toluene

1994

The group transfer polymerization (GTP) of n-butyl acrylate (nBuA) using 1-methoxy-1-(trimethylsiloxy)-2-methyl-1-propene (MTS) as an initiator, mercuric iodide (HgI2) as a catalyst in toluene at room temperature gives a very good control of molecular weight and narrow molecular weight distribution. (Mw/Mn < 1.2). Kinetic studies in this system reveal that this reaction is rather slow, half-lives being in the range of hours. The kinetic order of the apparent rate constant of propagation with respect to initiator and catalyst concentrations were found to be near to unity. However, the first-order time-conversion plots exhibit considerable induction periods. Upon addition of trimethylsilyl io…

Generalized model of the effect of pH on lactate fermentation and citrate bioconversion in Lactococcus lactis ssp. Lactis biovar. diacetylactis

1994

An aroma-imparting mesophilic lactic starter (Lactococcus lactis ssp. lactis biovar. diacetylactis) was studied in batch culture in medium with 50 g·l−1 lactose and 2 g·l−1 citrate. The effect of pH on the physiology of growth and the production of flavour compounds was investigated with a mathematical model. The specific rates of growth and of lactose fermentation obeyed a law of non-competitive inhibition by lactic acid produced, inhibition increasing as the pH of the medium decreased. The pH thus acted indirectly by increasing the proportion of non-dissociated lactic acid, identified as the inhibiting form of lactic acid. The generalized model, taking into account the effect of pH, was t…

Preparation and properties of Tl2Ba2CaCu2O8 thin films

1994

Anex situ process has been developed to produce thin superconducting Tl2Ba2CaCu2O8 films. The properties of films grown on different substrates using different annealing regimes were studied. Critical temperatures of 103–107 K were measured on films prepared in a broad range of annealing temperatures on SrTiO3, LaAlO3, and Y-ZrO2 substrates. A critical current density,Jc, of 2×106 A/cm2 at 77 K was measured on LaAlO3. Film morphology was studied by SEM, AFM, and STM.

Evaluation of a Computer Vision Based Automatic Incident and Congestion Detection System in an Urban Context

1994

Abstract The objective of the document is to describe an Automatic Incident and Congestions Detection System based on computer vision technology, in an urban environment. The document outlines the main technical features of the system and presents the first evaluation results obtained in a field trial currently carried out in protect INVAII) II. within the Transport Telematics Programme of the EC. CCTV cameras are installed in urban street intersections lor surveillance purposes. Based on image processing techniques. the Video Analyzers or Local Sensor Modules (LSM) connected to a number of selected cameras, obtain the traffic status measurements within the field of view of each one of them…

Solution Properties of Poly-Electrolytes. XI. Adsorption Effects in Aqueous Size-Exclusion Chromatog-Raphy of Polyanions

1994

Abstract Elution profiles of a series of polymer standards such as sodium poly(styrene sulphonate), poly(acrylic acid) and poly(L-glutamic acid) have been obtained from size-exclusion chromatography experiments using separately two types of hydrophilic supports. A variety of mobile phase compositions have been performed to enhance adsorption effects in order to study how this phenomenon can affect to the chromatographic separation mechanism of polyanions. Distribution coefficient values, in general greater than unity, have served to quantify the adsorption effect, as well as to analyze their dependence on eluent ionic strength, on the ionic groups of the support and on the chemical nature a…

Fate-mapping in the procephalic region of the embryonic Drosopbila head

1994

Using intracellular horseradish peroxidase injection we traced the developmental fate of early gastrula cells of the procephalic region in the stage 16/17 embryo. Morphogenetic movements in the developing brain are described in three dimensions. The results are related to head segmentation, and an early gastrula fate map of pregnathal head segments is proposed.

Acid and gastric metaplasia in the duodenum.

1994

Duodenal and antral mucosal biopsy specimens were obtained from 139 patients with dyspeptic complaints to study the prevalence and extent of gastric metaplasia in the duodenal bulb in relation to Helicobacter pylori (H pylori) infection and duodenal ulcer disease. On logistic regression, the presence and extent of gastric metaplasia was not significantly associated with H pylori infection. The prevalence of gastric metaplasia, however, was found to be higher in patients with current or past evidence of duodenal ulcer disease in comparison with subjects with functional dyspepsia (p = 0.01). A follow up study on 22 patients before and at least one year after eradication of H pylori showed tha…