No evidence of platelet activation in obesity.

1993

Retention behaviour of volatile compounds in normal-phase high-performance liquid chromatography on a diol column

1993

Abstract Retention data on a diol column for over 300 compounds of the chemical classes usually contained in aroma extracts of plants and foodstuffs are reported. A concept that largely corrects for minor fluctuations of the mobile phase composition and of the flow-rate was used to measure capacity factors. The mobile phase was composed of pentane and diethyl ether. The high volatility of these two solvents makes the method perfectly adaptable to the prefractionation of aroma extracts and the semi-preparative isolation of compounds. Non-polar compounds such as hydrocarbons are not retained on diol. Polar compounds can be readily eluted, with the exception of strong acids and bases.

The sex determining region of Chironomus thummi is associated with highly repetitive DNA and transposable elements.

1993

The dominant male sex determiner in chromosome III of the midge Chironomus thummi thummi is closely linked to a large cluster of tandem-repetitive DNA elements, the Cla elements, which are otherwise highly repetitive and distributed over more than 200 sites on all chromosomes. Chromosome III displays a hemizygous cluster of Cla elements in males but not in females. The chromosomal location of this hemizygous Cla element cluster is in the region of the male determiner M as localized by cytogenetic analysis. With Cla elements as hybridization probe, it was possible to clone a large part of the sex determining region. Molecular analysis of the DNA of males and females in this region displayed …

Temporary Employment in the Nordic Countries: A `Trap' or a `Bridge'?

1993

N,N,N-Alkyloctyldimethylammonium Chlorides in Water: A Thermodynamic Investigation

1993

Abstract Specific conductivities, densities, heat capacities and enthalpies of dilution at 298 K and osmotic coefficients at 310 K were measured for N,N,N -octylbutyldimethylammonium, N,N,N -octylpentyldimethylammonium, and N,N -dioctyldimethylammonium chlorides in water as functions of concentration. From the specific conductivity data, the CMC and the degree of the counterion dissociation have been calculated. It is shown that additional CH 2 groups in the variable alkyl chain affect both CMC and β less than they do in the single chain surfactants. The partial molar volumes, heat capacities, relative enthalpies, nonideal free energies, and entropies at 298 K were derived as functions of t…

Stochastic model for complex surface-reaction systems with application toNH3formation

1993

A stochastic model is introduced that is appropriate to describe surface-reaction systems. These reaction systems are well suited for the description via master equations using their Markovian behavior. In this representation an infinite chain of master equations for the distribution functions of the state of the surface, of pairs of surface sites, etc., arises. This hierarchy is truncated by a superposition approximation. The resulting lattice equations are solved in a small region which contains all of the structure-sensitive aspects and can be connected to continuous functions which represent the behavior of the system for large distances from a reference point. In the present paper, we …

A guide to the use of pore-forming toxins for controlled permeabilization of cell membranes

1993

Depending on the size of the pores one wishes to produce in plasma membranes, the choice will probably fall on one of the three toxins discussed above. S. aureus alpha-toxin should be tried first when pores of 1-1.5 nm diameter are required. This is generally the case when Ca2+ and nucleotide dependence of a given process is being studied. If alpha-toxin does not work, this is probably due to the fact that the toxin either does not produce pores, or that the pores are too small. In this case, high concentrations of alpha-toxin should be tried. If this still does not work, we recommend the use of HlyA. When very large pores are to be created, e.g. for introduction of antibodies into the cell…

Thirty years of synaptosome research.

1993

Detached synapses (synaptosomes), first isolated by the author in 1958 and identified as such in 1960, are sealed presynaptic nerve terminals often with a portion of the target cell--sometimes amounting to a complete dendritic spine--adhering to their external surface. They can be prepared in high yield from brain tissue and also in decreasing yield from spinal cord, retina, sympathetic ganglia, myenteric plexus and electric organs. They are sealed structures which, under metabolizing conditions, respire, take up oxygen and glucose, extrude Na+, accumulate K+, maintain a normal membrane potential and, on depolarization, release transmitter in a Ca(2+)-dependent manner. They thus provide an …

Pain therapy in acute renal colic

1993

Der extreme Schmerz einer Nierenkolik bedarf einer schnellen, nebenwirkungsarmen und suffizienten Schmerztherapie. Diese geht dem kausalen Therapieansatz, der Beseitigung der Harnwegsobstruktion, voraus. Durch den Einsatz von Prostaglandinsynthesehemmern ist eine direkte Beeinflussung der Pathophysiologie des Kolikschmerzes moglich. Mittel der ersten Wahl sind Metamizol, Indometacin und Diclofenac. Die Substanzen sollten, falls moglich, intravenos appliziert werden. Opiate und Opioide sind Mittel der zweiten Wahl. Auf die Gabe von Spasmolytika kann verzichtet werden.

Negative symptomatology: psychopharmacological strategies and methodological aspects for drug evaluation

1993

Thermodynamics of Toda lattice models: application to DNA

1993

Abstract Our generalised Bethe ansatz method is used to formulate the statistical mechanics of the classical Toda lattice in terms of a set of coupled integral equations expressed in terms of appropriate action-angle variables. The phase space as coordinatised by these action-angle variables is constrained; and both the soliton number density and the soliton contribution to the free energy density can be shown to decouple from the phonon degrees of freedom and to depend only on soliton-soliton interactions. This makes it possible to evaluate the temperature dependence of the soliton number density which, to leading order, is found to be proportional to T 1 3 .

Relaxation and phonons in viscous and glassy orthoterphenyl by neutron scattering

1993

We present an extended set of incoherent neutron scattering measurements on the van der Waals liquido-terphenyl, obtained by time-of-flight and backscattering spectroscopy. In the supercooled liquid regime, data from three instruments are combined and analysed in terms of the selfcorrelationS(Q, t). In the time range 1...100 ps, the crossover from α-to β-relaxation is well described by the masterfunction of mode coupling theory, and fitted parameters are consistent with the previously established critical temperatureT c [Z. Phys. B83, 175 (1991)]. In the glassy regime, vibrations are harmonic and can be described by a density of states. Deviations at lowQ are quantitatively explained by a m…

Thalamic hyperdensity — is it a diagnostic marker for Sandhoff disease?

1993

Sandhoff disease, also known as GM2-gangliosidoses variant 0, is caused by the deficient activity of both hexosaminidase A and hexosaminidase B. We report a 15-month-old boy diagnosed with Sandhoff disease by demonstrating the enzyme deficiency. The interesting finding was bilateral thalamic hyperdensity on the CT scan. The hyperdensity in all previously published cases was homogeneous and symmetric and limited to the thalamus; the cause still remains unknown. We suggest that the finding of dense thalami may be useful as a specific diagnostic criterion for the GM2-gangliosidoses and especially for Sandhoff disease.

Extended irreversible thermodynamics of liquid helium II

1993

In this work a macroscopic monofluid theory of liquid helium II, which is based on the extended irreversible thermodynamics, is formulated both in the presence and in the absence of dissipative phenomena. The work is a generalization of previous papers, where the extended thermodynamics of an ideal monoatomic fluid was applied to liquid helium II. It is shown that the behavior of helium II can be described by means of an extended thermodynamic theory where four fields, namely density, temperature, velocity, and heat flux are involved as independent fields. In the presence of dissipative phenomena, constitutive relations for the trace and the deviator of the nonequilibrium stress tensor are …

Determination of Homovanillic Acid in Human Plasma Using HPLC with Electrochemical Detection and Automated Solid Phase Extraction

1993

Abstract An isocratic HPLC method with electrochemical detection for the quantification of homovanillic acid (HVA) is described. The method included automated solid phase extraction on C-18-reversed phase material, followed by separation on a 3-μm Nucleosil 100 C18 column (250 mm × 4.6 mm I. D.) with a 100 mM citric acid solution (pH 6.6) containing 4% acetonitrile (v/v) as eluent at a flow rate of 0.6 ml/min. Isovanillinic acid served as internal standard. Extractability of both analytes was ca. 80 %. After extraction of 1 ml of plasma, coefficients of variation of replicate analyses were below 10 % in the naturally occuring concentration range.

Precursor-based synthetic pathways to nanometer NdNiO3−x particles

1993

Abstract The oxygen deficient neodymium nickel perovskite, NdNiO3−x, has been obtained by different low temperature-low oxygen pressure synthetic procedures. Besides a solid-matrix based route, both ordered and disordered chemical-precursors have been used as starting products. X-ray powder diffraction shows that the structure of this defective perovskite is orthorhombic. The study of the grain morphology of the products as resulting from the different synthetic procedures indicates that the main parameter determining the average particle size, which is in the nanometer range, is the maximum temperature achieved in the synthesis. Resistivity and DSC measurements show the existence of a meta…

Participation of Intracellular Calcium Stores in Serotonin-Induced Contractions in Rat Aorta

1993

Serotonin 1 mumol/l induces a contractile response in the isolated rat aorta in both the presence or absence of extracellular Ca. The present study analyzes the influence of temperature and caffeine on subsequent serotonin-induced contractions. In Ca-free medium, the contraction elicited by serotonin was higher at 25 degrees C than at 37 degrees C. In addition, the existence of two independent intracellular Ca pools releasable by serotonin, one of them also sensitive to caffeine, is postulated. The results also showed that addition of serotonin decreases the contractile response to this agonist in Ca-free medium.

Metabolism of Linoleic Acid or Mevalonate and 6-Pentyl-α-Pyrone Biosynthesis by Trichoderma Species

1993

The understanding of the biosynthetic pathway of 6-pentyl-α-pyrone in Trichoderma species was achieved by using labelled linoleic acid or mevalonate as a tracer. Incubation of growing cultures of Trichoderma harzianum and T. viride with [U- 14 C]linoleic acid or [5- 14 C]sodium mevalonate revealed that both fungal strains were able to incorporate these labelled compounds (50 and 15%, respectively). Most intracellular radioactivity was found in the neutral lipid fraction. At the initial time of incubation, the radioactivity from [ 14 C]linoleic acid was incorporated into 6-pentyl-α-pyrone more rapidly than that from [ 14 C]mevalonate. No radioactivity incorporation was detected in 6-pentyl-…

The influence of the “hot”-dimer adsorption mechanism on the kinetics of a monomer-dimer surface reaction

1993

“Hot” dimers are molecules which after adsorption dissociate and each of the remaining “hot” monomers fly apart up to a maximum distance R from the original adsorption site. The influence of the “hot”-dimer adsorption mechanism on relevant aspects of the bimolecular catalyzed reaction of the type A − (1/2)B2(“hot”) → AB is studied by means of the Monte-Carlo simulation technique. The temporal evolution of both the reactant's coverages as well as the rate of AB-production is evaluated and discussed. Due to the enhanced probability of “hot” species for encounters with other adsorbed particles, the rate of AB-production becomes faster when increasing R. This behavior may be relevant in the dyn…

Immunohistochemical determination of estrogen and progesterone receptor content in human breast cancer

1993

Immunohistochemistry of Estrogen Receptor (ER) and Progesterone Receptor (PR) has been performed in 687 cases of human breast cancer. The staining results have been compared by (1) computer-assisted image analysis (QIC Score) and (2) subjective grading of the cryostat sections ("German" IRS). Tumors without or with only weak ER or PR content may be distinguished by both methods from tumors with a high receptor content. The QIC Score values belonging to the intermediate IRS grades are distributed over a wide range, but no negative cases were found in these categories. It is concluded from our results that subjective grading of the slides is a simple, rapid and useful method for the determina…

Rapid microwave assisted hydrolysis of formetanate

1993

Abstract A fast microwave-assisted hydrolysis procedure has been developed for the derivatization of formetanate previously to the flow-injection spectrophotometric determination of m -aminophenol by reaction with p -aminophenol. Formetanate is quantitatively hydrolyzed with 0.1 M NaOH in 150 s using a closed polyetrafluoroethylene reactor with 115 ml internal volume and a radiation power of 390 W. The above procedure has been applied, as a previous step, for the flow-injection spectrophotometric determination of formetanate in spiked water samples and accurate and precise results have been found. The method permits to obtain a limit of detection of 0.025 mg 1 −1 of formetanate. The relativ…

Preparation of mixed oxides MNdO3, with M=Cr, Fe. Comparison of several methods

1993

Abstract Different methods for the formation of NdCrO3 and NdFeO3, having the perovskite-like structure, were studied including the ceramic method, simultaneous precipitation of hydroxides and simultaneous crystallization from aqueous solutions of nitrates. Preparation of mixed oxides from hydroxides simultaneously precipitated lowered the temperature and time required for their formation. In the case of NdCrO3 the formation process from hydroxides and nitrates occurred through the chromate, NdCrO4, without intermediate decomposition of the precursor to metal oxides, which lead to the mixed oxide by 600°C.

Synthesis, crystal structure and magnetic properties of [Cu2(bpym)(N3)4] (bpym=2,2′-bipyrimidine)

1993

Abstract The compound of formula [Cu 2 (bpym)(N 3 ) 4 ] (bpym=2,2′-bipyrimidine) has been synthesized and its crystal structure determined by X-ray diffraction methods. It crystallizes in the monoclinic space group P 2 1 / n with cell constants: a =10.071(2), b =6.376(1), c =11.617(2) A and β=95.93(1)°; V =742.0(2) A 3 , D (calc., Z =2)=2.029 g cm −3 , M r =453.4, F (000)=448, λ (Mo Kα)=0.71073 A, μ (Mo Kα)=29.1 cm −1 and T =298 K. A total of 2027 reflections was collected over the range 3⩽2θ⩽55°; of these, 1723 were unique and 1427 were considered as observed ( I >3σ( I )) and used in the structural analysis. The final R and R w residuals were 0.0275 and 0.0328, respectively. The structure…

Inclusive quasielastic neutrino reactions inC12andO16at intermediate energies

1993

Inclusive quasielastic neutrino (antineutrino) reactions on [sup 12]C and [sup 16]O at intermediate energies (50[lt][ital E][lt]400 MeV) are studied to investigate the effects of the nuclear medium on the total cross section and the energy spectrum of the outgoing leptons. The calculations are done in the local density approximation and various nuclear effects like Pauli blocking, Fermi motion, and strong-interaction renormalizations due to the presence of nucleons are taken into account. The corrections due to Coulomb effects are included which have been hitherto neglected in inclusive reactions. The results presented here are applicable to the inclusive reactions with neutrino beams plann…

A density functional for liquid3He

1993

We present a density functional for the description of liquid3He properties at zero temperature in a mean field approximation. Its basic ingredients are a zero-range, particle- and spin-density dependent effective interaction of Skyrme type, and a long-range effective interaction of Lennard-Jones type supplemented with a weighted density approximation similar to the one used in the study of classical fluids, to phenomenologically account for short range correlations. After fixing the value of its parameters, the functional yields a good description of the equation of state and Landau parameters (spin symmetric and spin antisymmetric as well) from saturation to solidification densities. The …

The onset of the rainy season in Yunnan province, PR China and its significance for agricultural operations

1993

Data of 134 stations located in Yunnan province, PR China were analysed in order to study the temporal and spatial characteristics of the onset of the rainy season and to investigate the consequences for farming operations. Using a precipitation threshold value, a time span of 12 weeks was found for the complete onset of the rainy season, while the range of onset dates varied from 37 days to 155 days. The onset occurred at different places across the province and showed active and break phases due to the interaction of four different branches of the atmospheric circulation. The onset of the growing season, determined by summing up decade precipitation totals, showed the same general pattern…

Scaling of the 4He(γ,p)t reaction in the Eγ = 80–160 MeV region

1993

The 4He(γ,p) 3H reaction cross section has been measured with tagged photons of energy 81–158 MeV. Protons were detected over the angular range 55°–125°. The scaling of the data as a function of momentum mismatch has been examined for two reaction models, the modified quasideuteron mechanism and quasifree knockout. Both models show clear scaling behaviour but comparison of the predicted and measured scaling function shapes favours the modified quasideuteron mechanism at momenta up to ≈500 MeV/c.

Molecular analysis in patients with mucopolysaccharidosis type II suggests that DXS466 maps within the Hunter gene

1993

Hunter disease is an X-linked mucopolysaccharidosis caused by deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). Using the IDS cDNA and DNA probes corresponding to loci flanking the IDS locus, we performed molecular genetic studies in two patients with Hunter syndrome. An interstitial deletion spanning the middle part of the IDS gene was found in the first patient. The second patient carries a gross gene rearrangement that can be detected after HindIII or EcoRI digestion of genomic DNA, and is similar to that found recently in seven unrelated Hunter patients. Our data suggest that the structural aberration observed is a partial intragenic inversion. As the same altered hybridiz…

Chemical characterization of peat fulvic acid fractions

1993

Abstract Milled peat fulvic acid (FA) preparation was fractionated by XAD-8 and conventional extraction methods. The fractions were further analyzed by IR and NMR and subjected to cupric oxide (CuO) oxidation. Carbohydrates of polydisperse FA were mostly not retained in the XAD-8 fractionation. The intensity of the signals due to double bonded carbons was much greater in the 13 C and proton NMR spectrum of the XAD-8 retained fraction than in the spectra of the XAD-8 non-retained or XAD-8 non-treated fractions. In CuO oxidation the main products of all FA fractions were 4-hydroxybenzaldehyde and 4-hydroxyacetophenone, both indicators of 4-hydroxyphenylpropane building blocks. Their concentra…

Structural study, thermal expansion and electrical conductivity of the composition NaSnZr(PO4)3

1993

Abstract The structure of the composition NaSnZr(PO4)3 and its evolution with temperature has been studied. The structure presents the space group R 3 c. The refinement of the structure shows that the Sn and Zr atoms are statistically distributed over the same crystallographic position. The unit cell expands in the c direction and contracts in the a direction, remaining the space group R 3 c at temperatures between 26 and 1000°C. The low value of the electrical conductivity at 400°C, 5.729×10−7S/cm and the low density of the pellets limited the use as electrical conductor.

Associations between type of treatment and illness-specific locus of control in type 1 diabetes patients

1993

Abstract This study examined differences in diabetes-specific locus of control beliefs of 82 insulin-treated Type I diabetes patients undergoing either conventional therapy (CT), intensified conventional therapy (ICT) or continuous subcutaneous insulin infusion (CSII). Compared to CT with its adherence to a strict regimen, ICT and CSII allow a much greater flexibility in timing of meals and daily activities. On the other hand, such flexibility requires a much more active role of the patient. The hypotheses of higher internality and lower powerful others locus of control beliefs in ICT and CSII patients than in CT patients could be supported for powerful others locus of control only. A one-y…

Laser cooling of stored high-velocity ions by means of the spontaneous force

1993

A longitudinal laser cooling of ion beams at about 5% of the velocity of light has been performed at the Heidelberg Test Storage Ring with various cooling schemes employing the spontaneous force. For a 7.29-MeV $^{9}\mathrm{Be}^{+}$ beam with an initial longitudinal temperature of 2700 K, the main characteristics of laser cooling in a storage ring are discussed. When undamped, the transverse betatron oscillations of the coasting ions limit the longitudinal temperature after laser cooling to typically 1 K. After damping the transverse motion by precooling the ions with an electron cooler, longitudinal temperatures of below 30 mK have been obtained in the subsequent laser cooling. In this cas…

Magnetic excitations of a doped two-dimensional antiferromagnet

1993

Magnetic excitations of the two-dimensional (2D) t-J model are considered in the presence of a small concentration of holes c. The spin-wave approximation used implies long-range antiferromagnetic ordering from the beginning. Migdal's theorem is shown to be valid for the model considered. The energy spectrum of the magnons is determined with the help of the one-pole approximation for the hole Green's function. If the concentration of mobile holes is larger than a critical value an additional branch of overdamped magnons arises near the \ensuremath{\Gamma} and M points of the Brillouin zone. This is connected with the generation of electron-hole pairs (the Stoner excitations) by magnons. The…

Representation of Strongly Stationary Stochastic Processes

1993

A generalization of the orthogonality conditions for a stochastic process to represent strongly stationary processes up to a fixed order is presented. The particular case of non-normal delta correlated processes, and the probabilistic characterization of linear systems subjected to strongly stationary stochastic processes are also discussed.

Transition metal derivatives of low oxidation state phosphorus oxoacids: synthetic pathways and structural studies

1993

Abstract A general synthetic approach intended to rationalize the solution preparative chemistry of transition metal phosphites and hypophosphites is presented. As previously shown for other derivatives containing also tetrahedral or pseudotetrahedral oxoanions, the hydrolytic processes affecting the cationic moieties play a determinant role on the very nature of the final solid. In fact, despite the limited number of donor atoms in the anions, the crystal chemistry of these compounds is quite intricate because of both the variety of possible cationic aggregates and the many ways to interconnect them through pseudotetrahedral anionic groups.

High‐temperature behavior of impurities and dimensionality of the charge transport in unintentionally and tin‐doped indium selenide

1993

A systematic study of the electron transport and shallow impurity distribution in indium selenide above room temperature or after an annealing process is reported by means of far‐infrared‐absorption and Hall‐effect measurements. Evidences are found for the existence of a large concentration of deep levels (1012–1013 cm−2), related to impurities adsorbed to stacking faults in this material. Above room temperature impurities can migrate from those defect zones and then become shallow in the bulk. The subsequent large increase of 3D electrons can change the dimensionality of the electron transport, which in most cases was 2D. The temperature dependence of the resistivity parallel to the c axis…