Dynamics of spin state conversion processes in the solid state

1989

High spin (HS) ⇌ low spin (LS) conversions in transition metal complexes are nonradiative transitions between spin states. In this contribution, we present a study of the temperature and pressure dependence of the HS ⇌ LS intersystem crossing dynamics. For some iron(II) spin-crossover complexes, the rate constants were determined by line shape analysis of57Fe Mossbauer spectra. Their temperature dependence is described by an Arrhenius equation, their pressure dependence is interpreted within absolute rate theory. HS → LS conversion rates at low temperatures were determined from the relaxation of light-induced formation of HS states, monitored by optical spectroscopy. Deviations from a simpl…

Minimal peripheral blood cells carrying clonal markers of b cell disorders: Evidence for monoclonality of circulating lymphocytes in patients with mu…

1989

Peripheral blood lymphocytes (PBL) of 20 patients with multiple myeloma (MM) were assayed for clonality by Southern blot and cell surface marker analysis. Eight samples showed monoclonal origin of circulating lymphocytes by demonstrating rearrangements of the heavy chain immunoglobulin gene (IgH). In selected experiments, comparison of IgH rearrangements of bone marrow plasma cells and peripheral blood-derived mononuclear cells, highly enriched for B lymphocytes, proved to be identical. However, monoclonal circulating cells could not be detected in samples with rearranged IgH genes by surface marker phenotyping using one-color immunofluorescence analysis and a panel of monoclonal and polycl…

High-level secretion of tumor necrosis factor-alpha contributes to hematopoietic failure in hairy cell leukemia [see comments]

1989

Abstract Hairy cell leukemia (HCL) is frequently associated with severe pancytopenia. The authors detected high levels of tumor necrosis factor (TNF)-alpha in the bone marrow serum of patients with HCL and found anti-TNF-alpha neutralizing monoclonal antibodies (MoAbs) to be able to enhance hematopoiesis of HCL patients in in vitro colony assays. As potent producers of TNF-alpha, hairy cells could be identified, thus implicating the malignant population in the pathogenesis of hematopoietic failure due to inappropriate secretion of this cytokine.

Determination of oestrogen receptors with monoclonal antibodies in fine needle aspirates of breast carcinoma.

1989

Fifty patients with operable breast carcinoma underwent fine needle aspiration for cytological examination. The smears were prepared by means of the immunocytochemical method using monoclonal antibodies for the determination of the oestrogen receptors (ER). After surgery the contents of the ER were determined with the traditional biochemical technique. The results of the immunocytochemical method showed 31 positives, two of which disagreed with the biochemical results, 15 negatives and four cases which could not be assessed due to the absence of adequate numbers of cells. The ICA staining for ER was expressed on a semiquantitative basis; there was a significant correlation between this and …

TERATOMI SACRO-COCCIGEI: Osservazioni su 25 casi

1989

Gli Autori presentano i dati relativi ad uno studio retrospettivo su 25 casi di Teratoma sacrococcigeo, osservati tra il 1980 ed il 1988.

Magnetic resonance imaging in primary cerebral neuroblastoma

1989

Testing the Form of a Decision-maker's Multiattribute Value Function Based on Pairwise Preference Information

1989

In a recent paper we presented a test, based on pairwise preference information, to identify to which class of functions (linear, quasi-concave, or neither) a decision-maker's (implicit) value function belongs. In this note we investigate the power of the test. Some improvements to the test are also suggested.

Production of thermal dileptons in high energy nucleus-nucleus collisions

1989

A method for including realistic nuclear geometry and impact parameter effects in computations of production rates of thermal dileptons of mass in the 1.5 to 3 GeV range andy≈0 in nucleus nucleus collisions at $$\sqrt s = 20 - 200$$ GeV is given. A comparison with the Drell-Yan rate indicates that for large nuclei and energies thermal production gives a sizable contribution even atM=M Jψ and thus may contribute significantly toJ/ψ suppression as background enchancement.

Two-dimensional isotropic orientational glasses: a computer-simulation study

1989

The analogue of the Edwards-Anderson model for isotropic vector spin glasses, but taking three-component quadrupoles instead of spins at each lattice site, is studied on the square lattice with extensive Monte Carlo calculations, using a nearest-neighbor symmetric gaussian interaction. It is shown that at low temperaturesT the model develops a short range order both with respect to glass like correlations and with respect to “ferromagnetic” correlations among the quadrupoles. The associated correlation lengths and susceptibilities diverge asT→0, and the critical exponents for this zero-temperature phase transition are estimated. Dynamic correlation functions are analyzed as well and it is s…

A M�ssbauer and ESR study of LiNbO3-Fe2O3 for low Fe2O3 concentrations

1989

Samples of the system LiNbO3-Fe2O3 prepared by water quenching and by the double-roller quenching method in the range up to 24 mol% Fe2O3 were investigated by Mossbauer and ESR spectroscopy. In the water quenched samples up to 11 mol% Fe2O3 only the Fe3+ and the Fe2+ valence states could be detected. The Fe2+ concentration decreased with increasing Fe2O3 content. Above 11 mol% Fe2O3 magnetically split Mossbauer spectra indicated the presence of Fe2O3 clusters. The isomer shift values of Fe3+ as a function of Fe2O3 concentration showed jumps at 6 and 11 mol% Fe2O3, whereas no significant changes could be detected in the quadrupole splitting values. The ESR data already exhibited the existenc…

Feinstrukturanalyse eines diskotischen Polymers durch Elektronenbeugung und hochauflösende Elektronenmikroskopie

1989

Majoron effects in rare kaon decays

1989

Abstract We analyze, in the framework of the recently introduced doublet majoron model, the contribution from the emission of a pair of light scalars to the decay K + → π + + nothing . We find that, for reasonable choices of the parameters, the new scalar contribution may be as large as one additional neutrino-antineutrino mode and provide a substantial modification of the pion spectrum. The effect may be a few times larger in the triplet majoron model.

Radiation tail in electron scattering: Approximations in the calculation and comparison to measurements

1989

Abstract Different approximations to the calculation of the radiation tail in electron scattering experiments are investigated with particular emphasis on problems related to the peaking approximation and to the convolution of the different contributions to the tail. The calculations are compared to measurements on C and W targets.

Polypeptides controlling hematopoietic cell development and activation. I. In vitro results.

1989

Recombinant DNA technology has been central in answering some of the most relevant questions in the research of regulation of the functional status of hematopoietic progenitor cells and their progeny. This leading article will focus on recent results that have emerged from studies utilizing recombinant molecules that control hematopoietic blood cell development and activation. The following features will be detailed: The molecular and biological characteristics and biochemistry of hematopoietic growth factors, synergizing factors and releasing factors, their role in the regulation of hematopoiesis and activation of normal and leukemic cells, their cellular sources, and regulation of product…

Medium for Screening Leuconostoc oenos Strains Defective in Malolactic Fermentation

1989

A new sensitive medium was developed to screen and isolate mutagenic Leuconostoc oenos strains defective in malolactic fermentation. The essential components of the medium included fructose (22 mM), l -malic acid (74.6 mM), bromocresol green (as pH indicator), and cellulose powder. The wild-type colonies turned blue, but defective malolactic colonies gave an acid reaction and remained yellow-green.

Elastic and quasielastic neutron scattering studies in KBr:KCN mixed crystals

1989

Neutron scattering studies in (KBr)1–x(KCN)x mixed crystals are presented utilizing powder diffraction, single crystal diffraction and time-of-flight techniques. Forx>0.6 (KBr)1–x(KCN)x crystals exhibit ferroelastic and ferroelectric low-temperature phases. Crystals withx<0.6 undergo transitions into an orientational glass state. Here we present a detailed phase diagram including new results for x=0.85 and x=0.65. For the latter system a stable rhombohedral low-temperature phase has been detected where the orientational disorder of the plastic phase is only partly removed and quadrupolar relaxations between three body diagonals are still possible. From the powder diffraction experimen…

Corrosion processes and their inhibition as studied by Mössbauer conversion and other electron spectroscopies

1989

To study corrosion processes of iron and steel and measures of their inhibition, a detailed knowledge of the phase composition and of phase transformations in very thin layers close to the attacked surface of the material is necessary. The information depths of integral (ICEMS) and depth selective (DCEMS) conversion electron Mossbauer spectroscopy are well suited for such investigations, but some effort is necessary if technical samples, i.e. nonenriched in57Fe, are to be studied. In many cases of practical importance, full information on the corroded surfaces cannot be got from Mossbauer spectra only, and a combination with Auger and photoelectron spectroscopies, in-including scanning and …

Poincaré's role in the Crémieu-Pender controversy over electric convection

1989

Summary In the course of 1901, V. Cremieu published the results of some experiments carried out to test the magnetic effects of electric convection currents. According to Cremieu, his experiments had proved that convection currents had no magnetic effects and consequently they were not equivalent to conduction currents, that is they were not ‘real’ electric currents. These negative results conflicted with those of well-known experiments carried out by other researchers, in particular with Rowland's experiments, and with Maxwell's, Hertz's and Lorentz's theories, which was more shocking. The publication of Cremieu's experiments raised a controversy which involved directly or indirectly some …

Therapeutic laser guidelines: On the effects of laser radiation on human skin-fibroblast metabolism in culture

1989

A promising field of laser utilization is the modification of cell behaviour. Acting on cell biological functions it might be possible to use them to improve medical therapies. This possibility suggests investigation of dosimetry guidelines employing different wavelenghts, power and exposure durations for future potential use of lasers in medicine.

Strategien bei Problemen mit rekursiver Lösung

1989

Recursion is not only a means for describing mathematical concepts, it is also an important problem solving tool in both mathematics and computer sciences. Recursion is the object of interest in our research project. In this article, we are going to report on an investigation aiming at the identification of strategies 7th and 8th graders use while coping with the recursive TOWER OFHANOI problem. Our hypothesis is that there are preliminary concepts for the concept of recursion which may vary for different students. We will describe some preliminary concepts in this paper.

Mucoepidermoid mammary carcinoma. Immunohistochemical and biochemical analyses of intermediate filaments.

1989

The histological features of mucoepidermoid mammary carcinomas (MMCs) are presented, and criteria for distinguishing these tumours from squamous epithelial metaplasia in other mammary carcinomas are considered. Immunohistochemical and gel-electrophoretic analyses of the intermediate-filament proteins in one MMC case revealed a complex pattern of cytokeratin polypeptide expression. The simple-epithelium-type cytokeratins 7, 8, 18, and 19 were detected mainly in nonsquamous (including mucinous) cells, while the stratified-epithelium-type cytokeratins 5, 6, 14, 16, and 17 were present in squamous cells. However, in both the nonsquamous and squamous regions of the tumour, cytokeratins of the "r…

Perkutane transluminäre Angioplastie nach transarterieller Schienung

1989

Cerebral arachnoid cyst: a lesion of the child's brain.

1989

39 patients with 42 arachnoid cysts have been reviewed in a retrospective study. All kinds of arachnoid cysts reported in the literature were also found in this study. These consist mainly of congenital primary and post-traumatic secondary cysts. Cysts which cause no major neurological deficits require conservative treatment of symptoms only. Cysts which cause major symptoms because of their space occupying nature, however, require surgical treatment. Craniotomy with removal of membranes to allow free physiological circulation of CSF is the treatment of choice in our hands. Cysto-peritoneal shunting is an alternative procedure for patients in a poor condition. More than 50% (23 out of 39 ca…

Comparacion de la presion arterial y transcutanea de oxigeno en la fibrobroncoscopia

1989

Se efectua un estudio comparativo de la presion parcial de oxigeno obtenida por puncion arterial (PaO 2 ) y con un electrodo de presion transcutanea de oxigeno (PtcO 2 ), tomadas simultaneamente antes y despues de la fibrobroncoscopia, realizada en 16 individuos con diversas patologias respiratorias. La fibrobroncoscopia produjo disminucion de la PaO 2 respecto a las cifras previas (F = 8,97; p 2 (F = 0,1; p = ns), existiendo con ambos metodos diferencias en la respuesta individual a la prueba. Se encontro escasa concordancia entre PaO 2 y PtcO 2 , tanto al inicio como al final de la exploracion. Consideramos por tanto que la determinacion transcutanea de oxigeno no puede sustituir a la art…

Structural „memory effects” influencing decompositions of glucose alkoxide anions produced from monoterpene glycoside isomers in tandem mass spectrom…

1989

Isomeric glycoconjugates have been distinguished using desorption negative-ion chemical ionization/tandem mass spectrometry (DNCI–MS/MS). The structure of the leaving terpene influences the orientation of consecutive decompositions during collisionally activated decomposition (CAD) of [M–H]− ions which pass through a glucose alkoxide intermediate ion. This apparent „memory effect” can be rationalized by considering the production of anion-induced dipole complexes.

SOLITON STATISTICAL MECHANICS AND THE THERMALISATION OF BIOLOGICAL SOLITONS

1989

Finances, Costs and Productivity of Higher Education

1989

Evapotranspiration: concepts and application

1989

International audience

Taprostene (CG-4203)

1989

Mathematical modeling of fetal limb growth

1989

Using ultrasound measurements of the femur, tibia, humerus, radius (N = 515), and fibula and ulna (N = 385) from normal fetuses between 12 and 40 completed weeks of gestation, growth models were determined for each bone by computer analysis. On the basis of residual analysis, growth of fetal limb bones could best be expressed as a function of tangens hyperbolicus. Growth profiles and growth data are shown with 5th, 10th, 50th, 90th, and 95th percentiles. These results are compared with previous investigations of limb bone measurements.

Nature of93Rb levels studied in IBFM

1989

The structure of the low-lying states with negative parity of3793Rb56 has been studied in the framework of the Interacting Boson-Fermion Model (IBFM) using the even-even neighbour3894Sr56 as a core. A good description of the properties of the levels has been obtained. A sensitive test of the quality of the theoretical studies is the decay pattern of the second excited state at 267 keV with a half-life of 2.0(2) ns. The calculations givet1/2=2.26 ns and they predict the existence of a 13 keV transition into the first excited state, the existence of which has been confirmed afterwards by experiments.

Antiproliferative effect of interferons on human prostate carcinoma cell lines.

1989

The effect of purified human fibroblast beta-interferon (B-IFN) and recombinant alpha-2b-interferon (A-IFN) on cell proliferation was investigated in two human prostate carcinoma cell lines, named PC-3 and DU-145. Both cell lines respond to the antiproliferative action of interferon, B-IFN being more effective than A-IFN. PC-3 is more sensitive than DU-145 cell line, showing 95% inhibition of cell proliferation at the highest concentration of B-IFN. As interferons, besides reducing cell growth, are able to modify steroid receptor content in different hormone-sensitive human tumours, our results may be of some relevance as these drugs might be used to regulate both cell proliferation and hor…

false

1989

The reaction kinetics for the group transfer polymerization (GTP) of tert-butyl methacrylate (TBMA) using a silyl ketene acetal initiator and a nucleophilic catalyst are investigated. The reaction is shown to be of first order in both monomer and catalyst concentrations. The “livingness” of this system appears to be influenced by the reaction temperature. At temperatures above −20°C, deactivation is observed, with its severity increasing with increasing temperature. This deactivation is attributed to a depletion of catalyst by side reactions. It was demonstrated that reactivation is made possible by the addition of more catalyst. This result is in contrast to the anionic polymerization of T…

Synthesen und Strukturen von Ethyl‐, Propyl‐, Butyl‐ und Mesitylantimon

1989

Die Enthalogenierung von Alkylantimondibromiden RSbBr2 (R = Et, Pr, Bu) mit Mg in THF fuhrt zu gelben Losungen, die uberwiegend die Antimonfunfringe (RSb)5 neben den Vierringen (RSb)4 enthalten. Die Trimeren (RSb)3 konnen massenspektrometrisch nachgewiesen werden. Beim Entfernen des Losungsmittels bilden sich reversibel die Polymeren (RSb)x (x » 5) in Form schwarzer Festkorper. In den Ringen nehmen die Substituenten R maximale trans-Positionen ein. Die Kristallstruktur von (MesSb)4 · Benzol enthalt linear …Sb4…Sb4…-verknupfte Cyclotetrastiban-Aren-Komplexe mit guter η6-Haptizitat des Benzolmolekuls an eines der vier Sb-Atome (Ringmitte…Sb 3.81 A, Winkel zur Flachennormale 5°). Der Sb4-Ring …

Internalized myofiber capillaries: Observations on their origin and clinical features

1989

Internalized capillaries limited to type 1 muscle fibers were noted in seven patients. They occurred in each case in association with a similar admixture of neurogenic and myopathic features that included atrophic and hypertrophic fibers, internal nuclei, fiber splitting, and endomyseal and perimyseal fibrosis. Internalized capillaries in enlarged type 1 fibers arose from fiber splits on step section study of four patients. They occurred in the gastrocnemius, quadriceps, and soleus muscles from patients with a variety of disorders that included Becker dystrophy, diabetes mellitus and strenuous leg activities, Achilles tendon rupture, and myotonic dystrophy. Exercise-induced myalgias were no…

IL LEMBO LIBERO di MUCOSA VESCICALE NELLA CORREZIONE DELL'IPOSPADIA

1989

Gli Autori descrivono l'utilizzo della muscosa vescicale nel trattamento dell'ipospadia