Demixing and polymerization in systems of anisotropic globular particles: A molecular dynamics simulation study

1991

We report a first set of results of Molecular Dynamics simulations of phase separation in a two-dimensional system of identical particles bearing attachment sites at their surface. Morphology of regions of aggregation so obtained appear similar to images of biologically self-assembled structures. Also, they evidence the relevance of the region of thermodynamic instability and of the presence and range of interaction of specific attachment sites. Particles of our system are apt to represent indifferently, though grossly, globular proteins or rigid cells, bearing specific and fixed adhesion sites at their surface. Results illustrate some basic aspects of the origin of the morphology of extend…

Quasi-compactness of dominated positive operators andC o-semigroups

1991

A new glucose-repressible gene identified from the analysis of chromatin structure in deletion mutants of yeast SUC2 locus.

1991

We have previously shown that some changes occur in the chromatin structure of the 3' flank of the yeast SUC2 gene in going from a repressed to an active state. In an attempt to find out the causes of these changes, we have carried out experiments in which mutant copies of SUC2 locus lacking either 5' or 3' flanks have been analysed for their transcriptional activity and chromatin structure. These experiments allowed us to discard any relationship between SUC2 transcription and chromatin changes within its 3'flank. Sequencing of this flank and mRNA analysis, however, resulted in the location of a putative peroxisomal 3-oxoacyl-CoA thiolase gene (POT1), which is repressible by glucose. The d…

Cycloaddition Reactions in Organic Synthesis. VonW. Carruthers. Pergamon Press, Oxford 1990. VIII, 373 S., Paperback $ 30.00. - ISBN 0-08-034712-6

1991

The oligomerisation of phenylacetylenes with rhodium(I) and P ligands as the catalytic system

1991

Abstract The dependence of the oligomerisation of phenylacetylene to cyclotrimers and dimers upon a Rh(I) complex with different P ligands as the catalytic system has been studied. The influence of substituents in the phenyl ring of the substrate has been examined as well. A selective cyclotrimerisation of phenylacetylenes is achieved with [1,5-C6H10RhCl]2 as the catalyst. A decrease of the selectivity appears with very bulky o-substituents or a substitution in the 2,6-position of phenylacetylene. [P]-control maps indicate a mono-association of the ligand accompanied by a reduced activity of the system. The second association of a P ligand results in an inhibition of the cyclotrimerisation …

The in vitro metabolic activation of dibenz[a,h]anthracene, catalyzed by by rat liver microsomes and examined by 32P-postlabelling.

1991

DNA has been incubated in vitro with dibenz[a,h]anthracene (DB[a,H]A) and the related 5,6-diol and 3,4-diol in the presence of 3-methylcholanthrene- or Aroclor 1254-induced rat liver microsomes. After incubation, the DNA was extracted and examined for the presence of aromatic adducts using the nuclease P1 modification of the 32P-postlabelling technique. The maps of PEI-cellulose plates and autoradiography showed that 92% of the radioactivity contained in DB[a,h]A-DNA adduct spots is derived from the related 3,4-diol and that about 50% of the adducts may be formed following the conversion of this diol to the bay-region anti- and syn-3,4-diol 1,2-oxides.

Action of the racemate and the isomers of the platelet-activating factor antagonist bepafant (WEB 2170) after oral administration to guinea-pigs and …

1991

The aim of the present study was to clarify whether there is a difference in terms of potency and pharmacodynamic half time between the isomers and the racemate of the platelet-activating factor antagonist WEB 2170 (bepafant) after oral administration to guineapigs or rats. The following experiments were performed in the guinea-pig. Infusion of platelet-activating factor at 30 ng/ (kg × min) for 30 min to anaesthetized guinea-pigs induced a decrease of respiratory flow and mean arterial blood pressure. Oral pretreatment with WEB 2170 or isomers, respectively, 60 min before infusion of plateletactivating factor inhibited these changes in a dose-dependent manner. The ED50S for inhibition of r…

On Horn spectra

1991

Abstract A Horn spectrum is a spectrum of a Horn sentence. We show that to solve Asser's problem, and consequently the EXPTIME = ? NEXPTIME question it suffices to consider the class of Horn spectra. We also pose the problem whether or not the generator of every Horn spectrum is a spectrum. We prove that from a negative solution of the generator problem, a negative answer for the EXPTIME = ? NEXPTIME question follows. Some other relations between the generator problem and Asser's problem are given. Finally, the relativized version of the generator problem is formulated and it is shown that it has an affirmative solution for some oracles, and a negative solution for some others.

Indirect majority and minority influence: An exploratory study

1991

In a 2 × 2 design, 85 subjects were asked to estimate the size of angles (direct influence) that were either 90 or 85°, after being confronted with incorrect judgements of a majority (88 per cent) or a minority (12 per cent) of people estimating the angles at 50°. Additionally, pre- and post-test measures were used to establish indirect influence on subjects' judgements pertaining to acute angles (i.e. on the estimation of the length of lines constituting the angles, and on the imaginary weight of figures represented by these angles). Overall, little direct influence is observed. This may partly be due to the introduction of a denial of the credibility of the source in all conditions. In fa…

Stimulation of pancreas and gastric carcinoma cell growth by interleukin 3 and granulocyte-macrophage colony-stimulating factor.

1991

Hematopoietic growth factors have recently been well characterized by complementary DNA scloning. For human epidermal growth factor, granulocyte-macrophage colony-stimulating factor recombinant proteins have been expressed in Escherichia coli . To reduce the toxic side effects of chemotherapy on the bone marrow, recombinant human granulocyte-macrophage colony—stimulating factor and recombinant human interleukin 3 were applied to patients suffering of gastrointestinal cancers. To determine the influence of recombinant human granulocyte-macrophage colony—stimulating factor and recombinant human interleukin 3 on human pancreas and gastric cancer cell cells in vitro, a sensitive microculture te…

Siderophore production in Aeromona spp. Isolated from European eel, Anguilla anfuilla L.

1991

Coordination behavior of cinoxacine: Synthesis and crystal structure of tris (cinoxacinate) cobaltate(II) of sodium hexahydrate (HCx = 1-ethyl-4(1H) …

1991

The synthesis, crystal, and molecular structure of Co(Cx)3Na6H2O are reported. The Cobalt(II) compound crystallizes in the trigonal system, space group R 3 with Z = 6, in a cell of dimensions a= 18.688(7) (A), c= 20.142(6) A. Least-squares refinement of 1331 reflections [I≥3σ(I)] gave a final R = 0.088 for all observed reflections. The structure consists of anionic monomeric units of (Co(Cx)3−) and sodium cations. Three Cinoxacinate ions are chelated through Oceto and Ocarbox atoms. The Co(II) ion positioned on the third axis is bonded to six oxygen atoms in a slightly distorted octahedral environment.

Packing meterials with surface barriers, controlled distribution and topography of ligands for sample clean-up and analysis of biologically active so…

1991

Various types of, so-called, restricted access packings have been developed for sample clean-up and analysis of biologically active solutes by means of HPLC. The unique feature of these packings is that they prevent the access of matrix components such as protein whilst selectively retaining the drug components and their metabolites. This results from the fact that the particles of the packings possess a surface barrier for large solutes at the external or internal surface area and exhibit a controlled gradient in the chemical surface composition. They are grouped, according to their particle structures, into internal-surface reversed phases (ISRP), shielded hydrophobic phases (SHP), semi-p…

2p-shell admixtures in pion single charge exchange on 13C

1991

Abstract The pion charge exchange process 13 C (π + , π 0 ) 13 N(gs) is calculated with an extended nuclear wave function for the A=13 system that includes configurations outside the 1p-shell. A small amount of 2p-shell admixtures leads to an improved description of the experimental excitation function. We also find a strong sensitivity of the differential cross sections as well as asymmetry to contributions from higher shells.

Selftype is a special case

1991

It is pointed out that selftype is actually only a special case of a construct that has been well described in the literature.

Clonal analysis of liver-infiltrating T cells in patients with LKM-1 antibody-positive autoimmune chronic active hepatitis

1991

SUMMARY Autoantibodies against microsomal antigen of liver and kidney (LKM-1) are diagnostic markers for a subgroup of autoimmune chronic active hepatitis (AI-CAH). Cytochrome P4S0dbl, now classified as cytochrome P450 IID6, is the major antigen of LKM-1 antibodies. Immunohistological studies suggest that hepatic injury in AI-CAH is mediated by liver-infiltrating T cells. In the present study the specificity and function of liver-infiltrating T cells was analysed at the clonal level. Phenotypical characterization of 189 T cell clones isolated from four liver biopsies of LKM-1 antibody-positive patients showed an enrichment of CD4+CD8- T cells. Five CD4+CD8- T cell clones proliferated specif…

Laser spectroscopy and laser cooling of relativistic stored ion beams

1991

Abstract Experiments with relativistic ions at the test storage ring TSR [P. Baumann et al., Nucl. Instr. and Meth. A268 (1988) 531] demonstrate the potential of the interaction of laser light with energetic stored ions for spectroscopic purposes as well as for manipulation of the ion velocity. Latest results for Li+ ions are reported. At the ion energies available at ESR [B. Franzke, Nucl. Instr. and Meth. B24 B25 (1987) 19] it will become possible to prepare and store bare ions up to U92+. Experiments using these exotic beams are discussed and an outlook to the situation at even higher energies is given.

Investigation of the Effect of Duodenoscopy on Sphincter of Oddi Manometry

1991

To investigate whether endoscopy affects sphincter of Oddi (SO) manometry, three patients who had undergone previous cholecystectomy and had a T-tube in situ for drainage were studied. Manometry was performed using a perfused triple lumen manometry catheter (diameter 1.7 mm), which was advanced into the SO lumen through the T-tube. SO motility, baseline pressure, common bile duct pressure and duodenal pressure were monitored before and during endoscopy while the tip of the endoscope was in the mouth, esophagus (upper third, precardial), stomach and duodenum. Endoscopy and even a moderate insufflation of air necessary to pass the pylorus and inspect the papilla of Vater did not affect the pa…

Hydrophilic membranes based on poly(vinyl methyl ether-crosslinked-polystyrene) semi-interpenetrating networks

1991

Microporous membranes were prepared from poly(vinyl methyl ether - crosslinked-polystyrene) (PVME-cross-PS) semi-IPN's by extraction of poly(vinyl methyl ether) (PVME) with water. Membrane morphology and properties are fixed during the process of swelling, phase separation, PVME extraction and vitrification which occurs upon immersing the samples in water. The membranes are characterized by swelling (water uptake), the relative amounts of free and bound water, and their permselectivity towards KCI solution.

On the number of factors of Sturmian words

1991

Abstract We prove that for m ⩾1, card( A m ) = 1+∑ m i =1 ( m − i +1) ϕ ( i ) where A m is the set of factors of length m of all the Sturmian words and ϕ is the Euler function. This result was conjectured by Dulucq and Gouyou-Beauchamps (1987) who proved that this result implies that the language (∪ m ⩾0 A m ) c is inherently ambiguous. We also give a combinatorial version of the Riemann hypothesis.

Investigation of diffusion and migration of hydrogen, deuterium and tritium in palladium in a Hall field

1991

Abstract The migration of hydrogen, deuterium and tritium in palladium in a Hall field at 343 K was investigated, using resistance and isotope methods. It was found that all isotopes of hydrogen migrate towards the negative Hall electrode. The effective charges of the migration in a Hall field are 194 ±3 e for hydrogen and 464± 5 e for deuterium and tritium. The results obtained confirm predictions of a tentative model based on the electron-balistic theories of migration in a Hall field.

Polyhedral results for a vehicle routing problem

1991

Abstract The Vehicle Routing Problem is a well known, and hard, combinatorial problem, whose polyhedral structure has deserved little attention. In this paper we consider the particular case in which all the demands are equal (since in the general case the associated polytope may be empty). From a known formulation of the problem we obtain the dimension of the corresponding polytope and we study the facetial properties of every inequality in it.

Evidence for T cell receptor-HLA class II molecule interaction in the response to superantigenic bacterial toxins

1991

The staphylococcal enterotoxins and related microbial T cell mitogens stimulate T cells by cross-linking variable parts of the T cell receptor (TcR) with MHC class II molecules on accessory or target cells. In this report we describe that a given combination of T cell, accessory cell (AC) and toxin can be non-stimulatory. However, the same T cell can respond to the same toxin on another AC and the same AC can present the same toxin to another T cell. This indicates that in the complex formed between TcR, toxin and class II molecule an interaction between TcR and class II molecule takes place.

Kinetics of particle growth and particle composition of a commercial Al-Li alloy by means of small-angle scattering

1991

Abstract Extending previous work done on a similar alloy, small-angle X-ray scattering measurements are reported for a commercial Al-Cu-Li alloy (2–68% Cu and 1–88% Li by weight). Data have been analysed by means of an ellipsoidal model of precipitate particles using a method previously proposed by some of us which, incorporating interparticle interference effects, reproduces the fuli scattering intensities of the samples studied. Particie dimensions obtained from the fit indicate that the Lifshitz-Slyozov coarsening mechanism holds for ageing at higher temperatures and longer times. The activation energy for volume diffusivity obtained is similar to that of pure binary alloys. The scatteri…

Erste Ergebnisse der bildzytometrischen DNS-Analyse zur Beurteilung der Prognose beim papillaren Schilddr�senkarzinom

1991

Bei 19 Patienten, bei denen wegen eines papillaren Schilddrusenkarzinomes eine Resektion durchgefuhrt worden war, wurde neben der TNM-Klassifikation und den ublichen morphologischen Beurteilungskriterien zusatzlich eine bildanalytische DNS-Zytometrie durchgefuhrt. Es fanden sich 13 diploide and 6 aneuploide Tumoren. Bei Patienten mit diploiden Tumoren betrug die rezidivfreie Uberlebensrate Bowie die Uberlebensrate nach 103 Monaten 84% bzw. 92%, wah-rend 3 von 6 Patienten mit nichtdiploiden Tumoren in nerhalb von 70 Monaten ein Rezidiv erlitten. Zwischen dem DNS-Gehalt der Tumoren einerseits and dem Tumorstadium, der pT-Einteilung, dem Vorhandensein von Lymphknotenmetastasen and einer tumorb…

Computer vision profilometer: equipment and evaluation of measurements

1991

Abstract This paper describes a new equipment that measures roughness values by a computer vision (CV) technique. Measurements carried out by a CV profilometer are also evaluated. A laser source (power 2 mW), a cylindrical lens and a charge coupled device (CCD) TV-camera with a suitable optical system form an image of the profile of the sample under inspection. This image is then transformed into a binary image by thresholding and the line that divides the bright zone from the dark zone is the sample profile. From this line the characteristic roughness values can be calculated. The roughness measurements are carried out both by the CV profilometer and a stylus profilometer on eight specimen…

Characterization of endogenous noradrenaline release from intact and epithelium-denuded rat isolated trachea.

1991

1. Overflow of endogenous noradrenaline (NA) from the in vitro incubated rat trachea evoked by two periods of electrical field stimulation (S1, S2 at 3 or 15 Hz) or by high potassium (60 mM) was determined by high performance liquid chromatography (h.p.l.c.) with electrochemical detection. 2. In the presence of the neuronal uptake inhibitor desipramine, the alpha 2-adrenoceptor antagonist, yohimbine, enhanced the overflow of NA evoked by stimulation at 3 Hz by about 100% suggesting the presence of presynaptic inhibitory autoreceptors on the sympathetic nerves innervating the trachea. 3. When desipramine and yohimbine were present throughout the experiments, the overflow of NA evoked by the …

Acetazolamide-M(II) [M(II) = Co(II), Ni(II), Cu(II)] complexes with ethylamine, diethylamine, triethylamine, and potassium hidroxide

1991

Abstract Complexes of Co(II), Ni(II), and Cu(II) with dideprotonated Acm are synthesized and characterized. Acm acts as bidentate ligand through the N-sulfonamido atom and the N-thiadiazole atom except for K6CoAcm4·6H2O in which Acm behaves as monodentate through the N-sulfonamido atom.

Die perkutane Harnleiterokklusion

1991

One hundred and nineteen transrenal occlusions of 77 ureters were carried out in 71 patients. Thirty-one ureters were occluded by means of glue and in 21 Gianturco coils were introduced at the same time. Forty-six ureters were occluded by means of disposable silicone-filled latex balloons. Seventeen out of 31 ureters treated with glue (55%) and 32 out of 46 ureters with balloons (70%) were permanently occluded. On 42 occasions, re-occlusions had to be carried out, the average period from the initial occlusion being 2.5 weeks for glue and 19.5 weeks for balloons. In nine out of the 119 ureteric occlusions (7.5%), there were mild complications; these were easily treated and were of no consequ…

Problems with the Breitenlohner-Maison γ5-scheme in flavour changing neutral currents

1991

Abstract We calculate the flavour changing neutral current (FCNC) decay Z → Q q at one-loop order using two different γ 5 -prescriptions, namely the Breitenlohner-Maison-'t Hooft-Veltman (BM) γ 5 -scheme and a naively anticommuting γ 5 . The results obtained in the two schemes differ from one another. The BM γ 5 -scheme calculation violates the conventional Ward identity relating the Z → Q q and the unphysical scalar φ z → Q q proper vertices which the naive γ 5 -calculation satisfies. Hence, we conclude that it is incorrect to naively apply the BM γ 5 -scheme if the standard model is renormalized on-shell.

Molecular aggregates of quinuclidine and chlorophyll a

1991

A slightly polar molecule quinuclidine seems to form weakly bound aggregates in concentrated water solutions. Molecular dynamics simulation of a 6 mol water solution indicates clustering of quinuclidine molecules into an almost spherical structure with polar ends of the molecules pointing towards the solvent. Experimental evidence of aggregation was obtained by observing a small but obvious red shift of the o'' a absorption and a dramatic shortening of the fluorescence lifetime of the c n transition of concentrated solutions. The observed self-quenching is interpreted in terms of Frster model for energy transfer in the cluster. It is estimated that excitation may migrate on the cluster surf…

Serum androsterone conjugates differentiate between acne and hirsutism in hyperandrogenic women

1991

Objective To determine if among hyperandrogenic women acne may be differentiated from hirsutism by markers of peripheral androgen metabolism. Design Prospective outpatient study of 36 hyperandrogenic women and controls divided into groups based on the presence or absence of significant hirsutism and the presence or absence of moderate to severe acne. Serum levels of adrenal and ovarian derived androgens were elevated but similar in all patient groups. Interventions Measurement of serum androgens including metabolites of 5 α -reductase activity: 3 α -androstanediol glucuronide and sulfate and androsterone (A) glucuronide and sulfate. Results 3 α -androstanediol glucuronide and sulfate were e…

Colour-flow-mapping in patients with ventricular septal defect.

1991

Radiologische Verlaufskontrolle der Thoraxorgane beim Intensivpflegepatienten

1991

Correlation between chest radiographs and clinical indicators was studied in 212 patients in intensive care. 1. There was good correlation between raised pulmonary artery pressure and radiological signs of left heart insufficiency, but not with the value of central venous pressure. 2. Fever and leukocytosis nearly always precede radiological evidence of pneumonia; their persistence does not necessarily indicate persistent pneumonia. 3. Pneumonias, effusions, atelectases and emboli are more common on the right. 4. More than 70% of central venous catheters were incorrectly placed; most commonly, the catheter was placed too low. Life-threatening complications occurred in 1.3%.

Thiopentalkonzentrationsverlauf im Vollblut von schwangeren und nichtschwangeren Patientinnen in den ersten Minuten nach der Injektion

1991

Thiopentone concentrations in blood following injection of the induction solution (Thiopental, 2.5%) may be critical in the context of lethal complications arising during induction of anaesthesia and thereby the toxicological aspects of this drug can become an issue in forensic considerations. The study was designed to find out whether the dose of injected thiopentone may be calculated from blood levels measured in nine pregnant and ten non-pregnant patients. The doses injected ranged from 4-5 mg per kg body weight. The drug was administered as a single bolus dose to the patients undergoing Caesarean section. In the non-pregnant group the first dose of thiopentone was given over 25 s. After…

Variation in somatic cell count, California mastitis test, and electrical conductivity among various fractions of ewe's milk.

1991

Abstract Variation of three estimates of udder inflammation (SCC, California mastitis test, and electrical conductivity) among the foremilk, machine milk, and hand stripping samples were studied. Foremilk and hand stripping milks were taken from each individual teat; machine milk was taken from the entire udder. For this experiment a total of 30 Manchega ewes were subjected to machine milking during the 9th wk of lactation. Samples were taken in duplicate during two milkings on consecutive mornings. Significant differences were observed in the SCC and electrical conductivity, but not in California mastitis test, between foremilk and stripping milk The stripping fraction had higher SCC (70 ±…