showing 36 of ~574560 from 574555 documents
4-Vinylphthalic anhydride
1994
4-Vinylphthalic anhydride can be prepared from phthalic acid via bromination and subsequent olefination (Heck-reaction). Homo- and copolymerization with styrene was accomplished using AIBN as initiator. The copolymer compositions were determined by infrared-spectroscopy. The copolymerization parameters are rs=0,15 and rVPA=3,09, the corresponding Q, e values of 4-vinylphthalic anhydride are estimated as Q=3,34 and e=0.09.
Rey propietario o rey soberano
1994
La soberanía del rey en Ámerica.
Stannacycloalkyl and stannepinyl derivatives of dipeptides
1994
Stannacyclohexyl and stannacycloheptyl derivatives of dipeptides (CH2)nSnAA · xH2O (H2AA = H2GlyGly, with n = 5, x = 2 or n = 6, x = 1; H2AA = H2GlyAla, H2GlyVal, H2GlyMet, with n = 5, 6, x = 1) and stannepinyl glycylglycinate monohydrate have been obtained by the reaction of (CH2)nSnCl2 or stannepinyl dichloride with Na2AA. According to infrared and 119Sn Mossbauer data of the solid compounds, AA acts as a tridentate ONN ligand and tin has a trigonalbipyramidal environment. An analogous structure has been inferred from 1H, 13C, and 119Sn NMR data for the undissociated molecules in methanol solution.
Incidence and clinical importance of perioperative histamine release: randomised study of volume loading and antihistamines after induction of anaest…
1994
Although histamine release is recognised as a common event during anaesthesia and surgery, few clinicians judge the resultant cardiorespiratory disturbances serious enough to warrant prophylaxis with antihistamines. We have assessed the incidence and importance of histamine release in a randomised 2 x 2 factorial study. 240 patients representing a routine throughput of major general surgery were studied during a standardised induction of anaesthesia and preoperative loading of the circulation with either Ringer solution or Haemaccel-35, with or without antihistamine prophylaxis with dimetindene (H1) plus cimetidine (H2). Cardiorespiratory disturbances were graded as detectable, clinically r…
Metachromatic behavior of methylorange in the presence of ionenes
1994
The addition of different ionenes, polycations with defined structure and charge distances, to methylorange1 in very dilute solutions of water resulted in an observable shift of the absorption maxima from 464 nm to shorter wavelengths. The extent of this so-called metachromasy effect was found to be dependent on the nature of the hydrophobic unit of the polymer backbone. The comparison of UV/VIS spectra's of these solutions with the absorption of a film of a model substance — a dication with methylorange as counteranion — lead to the conclusion that ionenes undergo an exchange of the counteranions when added to a dilute solution of methylorange. Precipitation is slowed down, but the absorpt…
Molecular cloning of a tyrosine kinase gene from the marine spongeGeodia cydonium: a new member belonging to the receptor tyrosine kinase class II fa…
1994
We have isolated and characterized a cDNA from the marine sponge Geodia cydonium coding for a new member of the tyrosine protein kinase (TK) family. The cDNA encodes a protein of M(r) = 68,710, termed GCTK, which is homologous to class II receptor tyrosine kinases (RTKs). GCTK contains conserved amino acids (aa) characteristic of all protein kinases, and the sequences DLATRN and PIRWMATE which are highly specific for TKs. Furthermore, the sequence N-L-Y-x(3)-Y-Y-R is highly homologous to the sequence D-[LIV]-Y-x(3)-Y-Y-R found only in class II RTKs. The sponge TK, when compared with mammalian class II RTKs, shows maximum 31% homology in the TK domain indicating that this the oldest member o…
Combination chemotherapy of 5-fluorouracil, epidoxorubicin and mitomycin C in the palliative treatment of locally advanced and/or metastatic adenocar…
1994
Thirty-seven consecutive patients with advanced and/or metastatic gastric adenocarcinoma received a combination of 5-fluorouracil 600 mg/m2 on days 1, 8, 29, 36; epidoxorubicin 75 mg/m2 i.v. on days 1, 29; mitomycin C 10 mg/m2 i.v. on day 1. This cycle was repeated every 8 weeks. Out of a total of 34 evaluable patients, 2 (5.8%) had a complete response and 7 (20.6%) had a partial response with an overall median duration of 40 weeks (range 20-128). The median survival of responding patients was not reached after a mean follow-up of 76 weeks, while that of patients with no change and progressive disease was reached at 36 and 13 weeks respectively. Treatment was generally well tolerated with h…
The glass transition in polymer melts
1994
This paper presents some results of a Monte Carlo simulation for the glass transition in two- and three-dimensional polymer melts. The melt was simulated by the bond-fluctuation model on a d-dimensional cubic lattice which was combined with a two-level hamiltonian favouring long bonds in order to generate a competition between the energetic and topological constraints in the system. This competition prevents crystallization and makes the melt freeze in an amorphous structure as soon as the internal relaxation times match the observation time of the simulation set by the cooling rate. The freezing point of the melt, i.e the glass transition temperature Tg, thus depends upon the cooling rate …
Kinetic-Spectrophotometric Determination of Primary and Secondary Amines by Reaction with 1-2 Naphthoquinone-4-Sulphonate.
1994
Abstract A kinetic-spectrophotometric method for the determination of primary and secondary amines is described. It is based on the coloured reaction of these amines with sodium 1,2 Naphthoquinone 4-sulphonate (NQS) in the presence of a non-ionic surfactant. For each determination the optimum conditions were studied and found to be as follows: pH 10.5. Carbonate-bicarbonate buffer 0.1M, Triton X-100 0.1%, Temperature 45°C, and NQS 6.4 × 10−3 M and interval of time 45–180s at wavelength 490 nm. The parameters used for the quantitative determinations are the reaction rate and the increase in the absorbance of the kinetic curves. This procedure has been applied to the determination of ephedrin…
Domperidone plus Magnesium Hydroxide and Aluminum Hydroxide: A Valid Therapy in Children with Gastroesophageal Reflux: A Double-Blind Randomized Stud…
1994
To evaluate the efficacy of different drug combinations in treating severe gastroesophageal reflux (GER), we studied 80 children with GER. The patients were randomly divided into four groups: group A was treated with domperidone plus magnesium hydroxide and aluminum hydroxide, group B with domperidone plus alginate, group C with domperidone alone, and group D received placebo. At the time of diagnosis and 8 weeks after treatment the patients were clinically evaluated and underwent 24-h continuous esophageal pH monitoring. After treatment a complete regression of symptoms was observed in 16 of 20 patients in group A, in 8 of 20 in group B (A versus B, p < 0.018), in 9 of 20 in group C (A ver…
Psychological Factors in Childhood Asthma
1994
The influence of the personality of asthmatic children and their mothers on the course of their illness is analysed, taking as a basis a sample of 48 asthmatic children. This is done through the assessment of the role of personality in the change that takes place, after the application of various psychological treatments (relaxation, systematic desensitization and stress inoculation) in three variables: number of days of illness, symptomatic relief drug use and school absences. The results obtained highlight the influence of personality on therapeutic success. Consequently, this study shows the importance of tending to personality traits in order to forecast and improve the effectiveness of…
Resting energy expenditure and body composition in morbidly obese, obese and control subjects
1994
Resting energy expenditure (REE) was investigated by indirect calorimetry in relation to body composition and to different degrees of obesity in order to assess if a defective energy expenditure contributes to extra body fat accumulation. Differences were found between control subjects (group C; BMI 23 +/- 0.5 kg/m2, REE 5890 +/- 218 kJ/day; mean +/- SEM) and obese subjects (group O; BMI 34.2 +/- 0.9 kg/m2, REE 7447 +/- 360 kJ/day; P0.0001) and between group C and morbidly obese subjects (group MO; BMI 49.9 +/- 1.6 kg/m2, REE 8330 +/- 360 kJ/day; P0.0001); REE was not significantly different between groups O and MO. Body composition data were obtained by means of body impedance analysis. Ev…
Deflazacort in Duchenne dystrophy: Study of long-term effect
1994
A randomized double-blind controlled trial of deflazacort was conducted in 28 Duchenne muscular dystrophy patients either treated with deflazacort 2.0 mg/kg alternate-day therapy or placebo. The deflazacort group showed significant improvement in climbing stairs (P < 0.01), in rising from a chair, Gower's maneuver, and walking (P < 0.0025) after 6 months of treatment. After 1 year, all the above changes remained significantly improved and the MRC index was significantly better (P < 0.05) in the treated group. After 2 years, a significant change was found in the MRC index: higher scores in walking, chair rising (P < 0.02), and grade and time of Gower's maneuver (P < 0.05) were found. The mea…
Influence of anti-inflammatory flavonoids on degranulation and arachidonic acid release in rat neutrophils.
1994
We assessed the effects of 24 flavonoid derivatives, reported as anti-inflammatory, on lysosomal enzyme secretion and arachidonic acid release in rat neutrophils. Amentoflavone, quercetagetin- 7-O -glucoside, apigenin, fisetin, kaem pferol, luteolin and quercetin were the most potent inhibitors of β-glucuronidase and lysozyme release. The first com pound was also able to inhibit basal release. These flavonoids besides chrysin and to a reduced extent, naringenin, significantly inhibited arachidonic acid release from membranes. A correlation between degranulation and arachidonic acid release was found for this series of compounds. Structureactivity relationships and implications for the anti-…
Possibilities of multinuclear NMR in the chemistry of heteroorganic compounds
1994
Zeaxanthin Dependent and Zeaxanthin Independent Changes in Nonphotochemical Energy Dissipation
1994
Summary The influence of zeaxanthin on high-energy-state quenching (qE) of room temperature chlorophyll fluorescence and on the quantum yield of oxygen evolution(ФO2) has been studied with isolated spinach thylakoids. A set of three different pretreatments was tested which all led to thylakoids with high contents of zeaxanthin. Depending on the presence of light the pretreatments differed strongly with respect to their effect on nonphotochemical fluorescence quenching. Independently from the extent of changes in nonphotochemical energy dissipation in the membrane energized state as reflected by nonphotochemical quenching the light pretreatments caused also changes in nonphotochemical energy…
Perspectives de croissance des dépenses d'enseignement supérieur
1994
Référence interne : 94040
Laboratory control of minimal heparinization during haemodialysis in patients with a risk of haemorrhage
1994
Abstract For patients undergoing dialysis with a high risk of haemorrhage there is no standardized procedure for anticoagulation during extracorporeal circulation. Minimal heparinization with a dose equivalent to half that used for chronic haemodialysis was employed in 49 patients (125 haemodialyses) performed after operative interventions (83.3%), after haemorrhagic events (5.2%) and after invasive investigations (11.5%). Using a biocompatible membrane and a low molecular weight heparin (bolus dose 500-1300 U; continuous infusion 100-400 U) it was possible to complete haemodialysis in 74 cases (Group 0) without clots appearing in the venous bubble trap of the tubing system. In 30 cases (Gr…
Photo and electroproduction of mesons
1994
The lecture provides an elementary introduction to photo and electroproduction of pseudoscalar mesons in the resonance region. After discussing the general structure of the elementary production amplitude and its symmetry properties the formalism is applied to some interesting physical problems.
Cytokeratins in the Histological Diagnosis of Malignant Tumors
1994
Cytokeratins, which comprise a multigene family of 20 related polypeptides (CKs 1–20), are constituents of the intermediate filaments of epithelial cells, in which they are expressed in various combinations depending on the epithelial type and the degree of differentiation. Of these, CK 19 (400 amino acids; 44.1 kilodaltons) is an example of a widely distributed CK, being expressed in various epithelia, including many simple epithelia. In contrast, the recently identified CK 20 (424 amino acids; 48.6 kilodaltons) is essentially confined to gastrointestinal epithelia, the urothelium and Merkel cells. The differential expression of individual CKs in various types of carcinomas makes them use…
On the mechanism of action of phenylephrine in rat atrial heart muscle
1994
Both in rat left atrial heart and in aortic smooth muscle preparations, phenylephrine (PE) caused a concentration-dependent increase in force of contraction (FC) in the presence of atenolol (10 mumol/l), which was antagonized by phentolamine, prazosin and WB 4101 in a competitive manner. The pA2 values of the antagonists in the cardiac tissue were 10-20fold lower than those in the rat thoracic aorta. In the spontaneously beating right atrium, PE exerted a positive chronotropic action, which was not significantly antagonized by phentolamine or prazosin. It is therefore assumed that the effects of phenylephrine in the left atrium and in the aorta are mediated by different subtypes of alpha 1-…
Les effets négatifs de la dévaluation du Franc CFA sur l'éducation sont-ils inéluctables ?
1994
International audience
An integral representation for decomposable measures of measurable functions
1994
We start with a measurem on a measurable space (Ω,A), decomposable with respect to an Archimedeant-conorm ⊥ on a real interval [0,M], which generalizes an additive measure. Using the integral introduced by the second author, a Radon-Nikodym type theorem, needed in what follows, is given.
FU-3 monoclonal antibody: a specific marker for malignant fibrous histiocytoma? An analysis of 32 malignant soft tissue and bone sarcomas.
1994
An immunohistochemical study on frozen sections was carried out on 51 malignant tumours of soft tissue and bone using the FU-3 monoclonal antibody. This antibody is claimed to be specific for malignant fibrous histiocytoma (MFH) and liposarcoma and for normal and tumour cells located in perivascular fields. The results show a lack of specificity in MFH staining: several malignant tumours such as synovial sarcoma, fibrosarcoma, rhabdomyosarcoma, osteogenic sarcoma, and including an anaplastic malignant melanoma, presented positive staining somewhat similar to that found in MFH. The value of this antibody in the differential diagnosis of MFH is doubtful. It might be useful to recognize a comm…
Möglichkeiten und Grenzen der Spiral-CT bei der Untersuchung von Nierenbeckenkarzinomen
1994
PURPOSE To assess the value of spiral CT in comparison to conventional CT in the staging of renal pelvic carcinoma. PATIENTS AND METHODS 35 patients with renal pelvic carcinoma underwent preoperative CT; conventional technique (n = 21) and spiral CT (n = 14) with the reconstruction of thin sections were compared. RESULTS Non-invasive or minimal invasive tumours (TA, T1, T2) could not be differentiated with either technique. Small, flat tumours (TA) or multicentric tumours may be missed, even if spiral scanning is applied. The separation of local tumour growth from infiltration is significantly improved by spiral CT (12 of 12 patients instead of 18 out of 21 patients with the conventional te…
Isotopic product distributions in the near symmetric mass region in proton induced fission ofU238
1994
We have studied fission product yields using 19.8 MeV proton induced fission of a thin $^{238}\mathrm{U}$ target and the on-line mass separator IGISOL. The nonselectivity of the separation method used with respect to Z has allowed accurate determination of the yields of symmetric fission for the first time. The cumulative yields for the elements from Z=40 (Zr) up to Z=47 (Ag) have been determined from the beta- and gamma-radioactivity measurements. The independent fission product yield distributions for elements Tc, Ru, and Rh are obtained from the experimental data. An improved theoretical model for calculating mass and independent yields is described and applied. It is found that the char…
Clinical Psychology: Current Status and Future Prospects
1994
La psychologie clinique espagnole a une courte histoire d'a peine vingt ans. Les diplomes universitaires de psychologie clinique ont ete crees il y a maintenant une douzaine d'annees. Il est frappant de constater que leur apparition est contemporaine de l'avenement du processus de democratisation. Dans cet article, nous examinons les principales innovations legislatives a l'origine de son actuel statut scientifique et professionnel, ainsi que sa situation presente en tant que formation universitaire, specialite et profession. Par la meme occasion, nous soulignons les problemes qui restent en suspens et le besoin urgent de conforter la psychologie clinique en creant des structures qui lui so…
Stickoxid (NO): Umweltgift und körpereigener Botenstoff
1994
Interferon-α for chronic hepatitis C: An analysis of pretreatment clinical predictors of response
1994
To identify predictors of short-term and sustained ALT normalization after interferon treatment in adult patients with chronic hepatitis C, we performed a metanalysis of individual patients'data, with construction and cross-validation of a prediction rule, in 361 patients from two randomized trials. In one trial, 116 subjects with transfusion-related chronic hepatitis C were treated with lymphoblastoid interferon (5 MU/m 2 three times a week for 2 mo, then 3 MU/m 2 three times a week for 4 or 10 mo)
The Years in Mainz — II
1994
1H-naphtho[2,1-b]thiete and 2H-naphtho[2,3-b]thiete- synthesis and reactivity
1994
Abstract The title compounds 4 and 8 are obtained by flash vacuum pyrolysis of the corresponding hydroxymethylthionaphthols 3 and 7. Whereas 4 shows a smooth ring opening on heating, 8 is thermally stable but reacts photochemically. The different behavior is explained on the basis of an MNDO calculation. The valence isomers 4′ and 8′ represent thioquinonemethides, which are highly reactive components in [12π + 2π]cycloaddition processes (4 → 9, 10, 11; 8 → 12).
Some Demographic and Economic Characteristics of Practitioners
1994
Les donnees presentees ici sont extraites d'une grande enquete realisee en Mars 1990 aupres des praticiens espagnols. On a travaille sur un echantillon stratifie tire au hasard. L'essentiel des conclusions touche a la jeunesse de ce groupe professionnel et a l'existence de discriminations dues au sexe pour ce qui est des conditions de travail et des avantages economiques. Il existe des differences frappantes entre les diverses specialites en ce qui concerne les heures de travail, le type d'organisations qui les accueillent, le salaire et l'assujetissement fiscal. Les demissions sont essentiellement dues a des raisons d'ordre economique. Une profession n'existe que si elle est pourvue d'un s…
Rapidity distributions of dileptons from a hadronizing quark-gluon plasma
1994
It has been predicted that dilepton production may be used as a quark-gluon plasma probe. We calculate the rapidity distributions of thermal dileptons produced by an evolving quark-gluon plasma assuming a longitudinal scaling expansion with initial conditions locally determined from the hadronic rapidity density. These distributions are compared with Drell-Yan production and semileptonic charm decays at invariant mass $M = 2$, 4, and 6 GeV.
External-ion accumulation in a Penning trap with quadrupole excitation assisted buffer gas cooling
1994
Abstract A pulsed ion beam from an external source is injected into a Penning trap and accumulated by repeatedly lowering during ion capture to prevent the ions already captured from escaping. For the same reason the newly captured ions have to be cooled, which achieved by buffer gas collisions. To prevent radial on loss, the ions are exposed to azimuthal quadrupole excitation. By choosing the appropriate frequency (range) this method (selective quadrupole excitation assisted capture and centering (SQUEACE) allows a mass selection during the capture process and leads to a centering of those ions in the Penning trap. The multiple ion bunch capture results in a significant improvement in sign…
Some comments on the history of vacuum microbalance techniques
1994
Abstract Based on the reviews of Behrndt, Iwata, Duval, Jenemann and Gast, we present a chronology of vacuum microbalance techniques in table form. The earliest discoveries of weights and balances are dated to about 3000 B.C. In the 19th century, balances were operated in vacuum for meteorological purposes. Thermogravimetry began with Talabot who, in 1833 in Lyon, equipped a laboratory with thermobalances for quality control of Chinese silk. At the beginning of the 20th century, microbalances were placed in high-vacuum apparatus.
Dietary protein deficiency affects n-3 and n-6 polyunsaturated fatty acids hepatic storage and very low density lipoprotein transport in rats on diff…
1994
Fatty livers and the similarity between the skin lesions in kwashiorkor and those described in experimental essential fatty acid (EFA) deficiency have led to the hypothesis that protein and EFA deficiencies may both occur in chronic malnutrition. The relationship between serum very low density lipoprotein (VLDL) and hepatic lipid composition was studied after 28 d of protein depletion to determine the interactions between dietary protein levels and EFA availability. Rats were fed purified diets containing 20 or 2% casein and 5% fat as either soybean oil rich in EFA, or salmon oil rich in eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, or hydrogenated coconut, oil poor in EFA. Animal…