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Background and purpose Augmented Na(+) /Ca(2+) exchanger (NCX) activity may play a crucial role in cardiac arrhythmogenesis; however, data regarding the anti-arrhythmic efficacy of NCX inhibition are debatable. Feasible explanations could be the unsatisfactory selectivity of NCX inhibitors and/or the dependence of the experimental model on the degree of Ca(2+) i overload. Hence, we used NCX inhibitors SEA0400 and the more selective ORM10103 to evaluate the efficacy of NCX inhibition against arrhythmogenic Ca(2+) i rise in conditions when [Ca(2+) ]i was augmented via activation of the late sodium current (INaL ) or inhibition of the Na(+) /K(+) pump. Experimental approach Action potentials (APs) were recorded from canine papillary muscles and Purkinje fibres by microelectrodes. NCX current (INCX ) was determined in ventricular cardiomyocytes utilizing the whole-cell patch clamp technique. Ca(2+) i transients (CaTs) were monitored with a Ca(2+) -sensitive fluorescent dye, Fluo-4. Key results Enhanced INaL increased the Ca(2+) load and AP duration (APD). SEA0400 and ORM10103 suppressed INCX and prevented/reversed the anemone toxin II (ATX-II)-induced [Ca(2+) ]i rise without influencing APD, CaT or cell shortening, or affecting the ATX-II-induced increased APD. ORM10103 significantly decreased the number of strophanthidin-induced spontaneous diastolic Ca(2+) release events; however, SEA0400 failed to restrict the veratridine-induced augmentation in Purkinje-ventricle APD dispersion. Conclusions and implications Selective NCX inhibition - presumably by blocking rev INCX (reverse mode NCX current) - is effective against arrhythmogenesis caused by [Na(+) ]i -induced [Ca(2+) ]i elevation, without influencing the AP waveform. Therefore, selective INCX inhibition, by significantly reducing the arrhythmogenic trigger activity caused by the perturbed Ca(2+) i handling, should be considered as a promising anti-arrhythmic therapeutic strategy.

Background and Purpose At present there are no small molecule inhibitors that show strong selectivity for the Na+/Ca2+ exchanger (NCX). Hence, we studied the electrophysiological effects of acute administration of ORM-10103, a new NCX inhibitor, on the NCX and L-type Ca2+ currents and on the formation of early and delayed afterdepolarizations. Experimental Approach Ion currents were recorded by using a voltage clamp technique in canine single ventricular cells, and action potentials were obtained from canine and guinea pig ventricular preparations with the use of microelectrodes. Key Results ORM-10103 significantly reduced both the inward and outward NCX currents. Even at a high concentration (10 μM), ORM-10103 did not significantly change the L-type Ca2+ current or the maximum rate of depolarization (dV/dtmax), indicative of the fast inward Na+ current. At 10 μM ORM-10103 did not affect the amplitude or the dV/dtmax of the slow response action potentials recorded from guinea pig papillary muscles, which suggests it had no effect on the L-type Ca2+ current. ORM-10103 did not influence the Na+/K+ pump or the main K+ currents of canine ventricular myocytes, except the rapid delayed rectifier K+ current, which was slightly diminished by the drug at 3 μM. The amplitudes of pharmacologically- induced early and delayed afterdepolarizations were significantly decreased by ORM-10103 (3 and 10 μM) in a concentration-dependent manner. Conclusions and Implications ORM-10103 is a selective inhibitor of the NCX current and can abolish triggered arrhythmias. Hence, it has the potential to be used to prevent arrhythmogenic events. Linked Article This article is commented on by Terracciano and Hancox, pp. 765–767 of this issue. To view this commentary visit http://dx.doi.org/10.1111/bph.12299

Background and purpose: The Na+/Ca2+ exchanger (NCX) may play a key role in myocardial contractility. The operation of the NCX is affected by the action potential (AP) configuration and the intracellular Na+ concentration. This study examined the effect of selective NCX inhibition by 0.1, 0.3 and 1.0 μM SEA0400 on the myocardial contractility in the setting of different AP configurations and different intracellular Na+ concentrations in rabbit and rat hearts. Experimental approach: The concentration-dependent effects of SEA0400 on INa/Ca were studied in rat and rabbit ventricular cardiomyocytes using a patch clamp technique. Starling curves were constructed for isolated, Langendorff-perfused rat and rabbit hearts. The cardiac sarcolemmal NCX protein densities of both species were compared by immunohistochemistry. Key results: SEA0400 inhibited INa/Ca with similar efficacy in the two species; there was no difference between the inhibitions of the forward or reverse mode of the NCX in either species. SEA0400 increased the systolic and the developed pressure in the rat heart in a concentration-dependent manner, for example, 1.0 μM SEA0400 increased the maximum systolic pressures by 12% relative to the control, whereas it failed to alter the contractility in the rabbit heart. No interspecies difference was found in the cardiac sarcolemmal NCX protein densities. Conclusions and implications: NCX inhibition exerted a positive inotropic effect in the rat heart, but it did not influence the contractility of the rabbit heart. This implies that the AP configuration and the intracellular Na+ concentration may play an important role in the contractility response to NCX inhibition.

Poly(ethylene terephthalate) (PET) surface was treated by plasma immersion ion implantation (Pill or PI 3 ) in nitrogen. The treatment conditions like acceleration voltage, ion fluence and fluence rate were varied systematically. The Pill-induced alterations in the surface chemical composition and bonding of the constituent elements were studied by XPS. Nanoindentation and nanoscratch measurements were applied to investigate the related changes in the hardness, elastic modulus and wear resistance. Nitrogen Pill treatment of PET led to incorporation of nitrogen and decrease of surface O/C ratio. The bulk plasmon loss energy of the C 1s peak increased, implying compaction of the surface layer. Pill treatment increased the mean surface roughness and hardness (H), and decreased the elastic modulus (E). Process conditions were found, under which a four-fold increase was obtained in the wear resistance. Improvement in wear resistance was accompanied by increase in the H/E ratio.

New siloxane-organic polyesters, bearing azo-type units in the side chain, were synthesized by direct solution polycondensation at room temperature, starting from 2,2'-[4-[(4-nitrophenyl)azo]phenyl]iminobisethanol (Disperse Red 19) and different siloxane diacids, using dicyclohexylcarbodiimide as an activator and 4-(N,N-dimethylamino)pyridinium-p-toluenesulfonate as the catalyst. The structure of the obtained polyesters was confirmed by 1 H and 13 C NMR as well as IR spectroscopy. The molecular weight and polydispersity were estimated by GPC. The thermotropic behavior was investigated by POM, DSC and TOA. The surface composition was determined by ESCA (XPS) analysis and proved enrichment in silicon for all samples. All compounds show good solubility in common organic solvents.

Ultra-high molecular weight polyethylene (UHMWPE) was treated by hydrogen plasma immersion ion implantation (PIII). Accelerating voltages (U) between 15 and 30 kV, fluences (F) between 1 x 10 17 and 3 × 10 17 cm -2 with fluence rates (FR) between 3 × 10 13 and 7 × 10 13 cm -2 s -1 were applied. The surface chemical characterisation was performed by XPS. Nanomechanical properties like hardness (H), reduced modulus (E) and slope of scratch (S) of the untreated and modified surfaces were characterised by nanoindentation and nanoscratch measurements. The results demonstrate that hydrogen PIII-treatment can significantly and favourably modify the nanomechanical properties of UHMWPE. The dependence of these properties on the main process parameters has been determined.

Plasma immersion ion implantation is an emerging, versatile, relatively simple and cost-effective surface modification technique, alternative to conventional ion implantation. With this method even irregularly shaped objects can be uniformly treated, enhancing thus their surface properties. Ultra-high molecular weight polyethylene is a principal biomaterial currently used in total joint arthroplasty, the wear of which and in particular the wear debris induced osteolysis is the main cause of the premature failure of the hip joint prostheses. In order to improve the wear resistance of ultra-high molecular weight polyethylene, in this work it was surface treated by plasma immersion ion implantation in helium. Process parameters like acceleration voltage, fluence and fluence rate were varied systematically. X-ray photoelectron spectroscopy was applied to monitor the surface chemical changes. Alterations induced in the surface mechanical and wear properties like hardness, reduced modulus and volume loss were determined by nanoindentation and multipass wear test measurements. The results demonstrate that the applied treatment can significantly modify the surface chemical and nanomechanical properties and increase the wear resistance of ultra-high molecular weight polyethylene. Copyright © 2006 John Wiley & Sons, Ltd.

Thin, modified surface layers were created on ultrahigh molecular weight polyethylene (UHMWPE) by treating them with low-energy (∼1 keV) fast atom beams (FAB) of argon, helium, hydrogen and nitrogen. Nanomechanical properties including multipass wear characteristics, dry friction coefficient and topography (roughness) were measured on these modified surfaces. As a result of FAB treatment, the volume loss—calculated from the geometrical characteristics of the Rockwell head and from the depth of the permanent scratch track—could decrease by more than 1 order of magnitude, implying a similar increase in the wear resistance. FAB treatment increased also the dry friction coefficient, while the mean roughness was not altered significantly. Copyright © 2006 John Wiley & Sons, Ltd.

The sodium-calcium exchanger (NCX) was considered to play an important role in arrhythmogenesis under certain conditions such as heart failure or calcium overload. In the present study, the effect of SEA-0400, a selective inhibitor of the NCX, was investigated on early and delayed afterdepolarizations in canine ventricular papillary muscles and Purkinje fibres by applying conventional microelectrode techniques at 37 degrees C. The amplitude of both early and delayed afterdepolarizations was markedly decreased by 1 microM SEA-0400 from 26.6+/-2.5 to 14.8+/-1.8 mV (n=9, P

Carbon–nickel (CNi) and carbon-nitride–nickel (CNxNi) films were deposited onto native SiO2 covered Si substrates by DC magnetron sputtering from a graphite–nickel composite target using Ar or N2 for sputtering at about 2.6 Pa. The substrate temperature varied between 25 and 800°C. The structure, composition and mechanical properties of CNi and CNxNi thin layers (200–300 nm) have been investigated by high-resolution transmission electron microscopy (HRTEM), XPS, nano-indentation and nano-scratch techniques. The layers were predominantly crystalline irrespective of their deposition conditions. At low deposition temperature, up to 200°C, the columnar crystallites were identified as hexagonal Ni3C, separated by narrow ‘walls’ of amorphous carbon. At substrate temperatures above 400°C, however, a graphitic multilayer arrangement of the carbon matrix was developed around the nano-crystalline cubic nickel–nickel carbide islands. The mechanical properties of the films varied also significantly with the deposition temperature. The highest nano-hardness of about 14 GPa was measured for the film grown at 200°C, while lower values (2–4 GPa) were obtained for high-temperature films. High hardness values were related to the presence of Ni3C. The lowest friction coefficients were obtained for films containing high amounts of multi-layered graphite-like carbon developed at intermediate deposition temperatures. Copyright © 2004 John Wiley & Sons, Ltd.

Surface modification of commercially pure Ti and of Ti6Al4V alloy samples was performed by plasma immersion ion implantation with 25 kV energy. Plasma was generated by RF discharge in air, in nitrogen, or in a mixture of nitrogen and methane. Treatment in air plasma produced an oxide layer on the surface without appreciable incorporation of nitrogen, as detected by XPS. Significant surface enrichment of aluminium was measured after air plasma treatment of Ti6Al4V, but no such segregation was observed after nitrogen plasma treatment. These effects are interpreted by involvement of thermodynamic driving forces. Development of rutile and a sub-stoichiometric oxide were identified on Ti while no crystalline phases could be evaluated on the Ti6Al4V upon oxidation. The cubic TiN phase was found after nitrogen PIII treatment on both Ti and Ti6Al4V. Nanomechanical tests showed a significant increase in the hardness for Ti6Al4V after oxidizing PIII treatment in air. Considerable change in hardness could not be measured, however, after nitriding PIII treatments. Copyright © 2004 John Wiley & Sons, Ltd.

This article deals with the study of the efficiency of different compatibilizing agents in the intumescent polypropylene/polyamide-6/ammonium polyphosphate (PP/PA-6/APP) blend. The migration of additive was first investigated by X-ray photoelectron spectroscopy. The study showed that ethylene–butyl acrylate–maleic anhydride is not efficient in preventing the exudation of APP to the surface. However, ethylene vinyl acetate (EVA) prevented such a phenomenon. Second, the modifications in the blends were analyzed as a function of their compositions. Optical microscopy analysis showed that adding EVA to PP/PA-6/APP promoted a decrease in the size of PA-6 droplets. X-ray diffraction was used to characterize the effect of each component on the PP crystallinity. It was clearly shown that the crystallinity depends on the composition of the blend. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 402–411, 2004

Novel polymeric azomethines of 5,5′-methylene-bissalicylaldehyde with two siloxane diamines {H2N(CH2)3(CH3)2SiO[(CH3)2SiO]mSi(CH3)2(CH2)3NH2, where m = 0 or 6.5} were obtained. Their structures were confirmed by elemental and spectral [IR, ultraviolet–visible (UV–vis), and 1H NMR] analysis. The obtained polyazomethines were converted into the chelates of some divalent metals (copper, cobalt, and nickel). The resulting complexes were characterized by electronic and IR spectral measurements, elemental analysis, and thermal studies. From IR and UV–vis studies, the phenolic oxygen and imine nitrogen of the ligand were found to be the coordination sites. The thermogravimetric data indicated that the chelates were less stable than the corresponding ligands and that the thermostability depended on the siloxane segment length and the nature of the metal. Both the macromolecular ligands and the parts of the resultant chelates were soluble in common organic solvents, such as CHCl3, CH2Cl2, dimethylformamide, and dimethyl sulfoxide. The surface compositions of the ligands and some chelates were examined by X-ray photoelectron spectroscopy. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3169–3179, 2003

The synthesis and characterization of some novel cationic siloxanes copolymers containing quaternary ammonium salt (QAS) groups in the backbone is reported in this article. One cationic oligomer having QAS in the backbone and reactive groups like 2,3-epoxypropyl and 2-hydroxy-3-chloropropyl (RCO) as well as 1,3-bis(3-aminopropyl)tetramethyldisiloxane or α,ω-bis(3-aminopropyl)oligodimethylsiloxane (AP) were used as precursors for this goal. Elemental analysis, IR and 1H NMR spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy were used to characterize the obtained copolymers. The thermal stability of the cationic siloxane copolymer increased when the siloxane oligomer having a high number of siloxane units in the chain (AP) was used as a precursor. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3570–3578, 2002

Metal arachidate Langmuir-Blodgett (LB) films with Pb 2+ and Cd 2+ cations and varying numbers of monomolecular layers (2 and 4 monolayers, ML) were deposited on trimethylsilylated glass substrates. The arachidate salt formation was commenced during the film deposition from a water-based solution. The extent of salt formation and the build-up of the LB layer were evaluated by quantitative XPS. The completeness of the salt formation was assessed by the atomic ratio of the carboxylic (-COO-)-type carbon component with C is binding energy at ∼288.5 eV to that of the selected line of the actual cation. The surface coverage of the glass substrate by the LB film was assessed by calculations based on a substrate-overlayer model using the XPS MultiQuant program. According to this model, the attenuation of the Si 2p photoelectron signal from the substrate by the 2 and 4 ML LB films (with 56 and 112 A thickness, respectively) was calculated and compared with the measured intensities, enabling the completeness of the layer to be evaluated. The layer thickness values calculated from the measured intensity of the layer constituents reflected accurately the thickness derived from the geometry of the arachidate molecule, confirming both the adequacy of the model and the accuracy of the measurement. In agreement with earlier results it was confirmed that salt-based LB films are fairly stable under high vacuum conditions, although slow decomposition of lead arachidate films was detected during prolonged x-ray irradiation.

Aluminium hydroxide and magnesium hydroxide powder samples coated by zinc hydroxystannate (ZHS) to various extents have been studied by x-ray photoelectron spectroscopy (XPS). For quantification of the XPS results a model was applied in which the substrate was covered by islands of ZHS, and this system was considered to be covered by a uniformly thin carbonaceous contamination overlayer. The surface coverage by ZHS and the thickness values of the carbonaceous and ZHS layers were determined for each sample by the recently developed XPS MultiQuant program. Relationships were established between the surface coverage, the layer thickness and the applied bulk concentration of ZHS. Low coating thickness values in the range of several nanometres have been obtained, which may account for the previously observed high flame retardant and smoke suppressant efficacy of zinc hydroxystannate-coated fillers when applied in various polymeric formulations.

Ultrahigh molecular weight polyethylene (UHMWPE) samples were implanted with 46 and 80 keV nitrogen ions up to a fluence of 10 17 ions cm -2 . The modified surface layers were studied by XPS, Fourier transform infrared spectroscopy (FTIR), Rutherford backscattering spectrometry, elastic recoil detection analysis and dynamic ultra-microhardness measurements. By XPS at relatively low fluences (∼10 15 ions cm -2 ) the dominant N 1s peak component was detected at ∼400 eV, which was attributed to C=N-type bonds. With increasing fluence the share of component at ∼398.5 eV, assigned to C-N-type bonds, increased significantly. Changes in the FTIR spectra reflected dehydrogenation (creation of trans-vinylene groups) and oxidation (creation of carbonyl groups). Rutherford backscattering spectrometry allowed the depth profiles of the elements to be obtained. In each case, the thickness of the oxygen-containing layer proved to be greater than that of the nitrogen-containing layer. Elastic recoil detection analysis revealed the formation of a layer with a characteristically graded hydrogen depletion. The thickness of this layer was greater than the projected range of the nitrogen ions. Significant improvement in the surface hardness was observed for the ion-implanted UHMWPE in the whole range of indentation depth studied.

This study examines the extent of union solidarity in two post-communist countries, Hungary and east Germany. It tests the hypothesis that post-communist union members are sceptical and unsupportive of their new interest representation owing to a legacy of disappointing experiences with their former communist unions. A survey of the union members, the first of its kind, in the Hungarian and east German clothing industry revealed strong differences between members’ attitudes in both countries: east Germans were highly committed and supportive of their new union and works councils, whereas Hungarians lacked support for their institutions. The study points to the complexities of former and current attitudes and rejects the generic use of a communist legacy thesis. Instead, it links members’ attitudes to the different institutional context of interest representation in the two countries. It argues that the dual system of interest representation in Germany facilitates members’ trust in their new institutions, whereas the decentralized, overlapping institutions on Hungarian shop-floors impede union solidarity.

Analogic CNN algorithms are presented for various interpolation and approximation tasks in 3D. They are designed on the basis of mechanical analogies. Symmetric space-variant operations are implemented by the CNN algorithms; with switched templates, a key example is object rotation. Direction and speed coding are shown in detail.

Ultra-high molecular weight polyethylene (UHMWPE) was surface treated by beams of various inert and reactive atoms in the low keV range. Sum frequency generation (SFG) spectroscopy showed the complete destruction of ordered packing at the topmost surface. Rutherford backscattering (RBS) and elastic recoil detection analysis (ERDA) revealed a strong surface dehydrogenation. Depth-sensing nano-indentation and nanoscratch measurements testified to alterations in the nanomechanical properties. A correlation has been established between the scratch resistance and the plasmon loss energy of the C 1s XPS peak.

Polyvinyltrimethylsilane films were bombarded by 1 keV and 5 keV Ar + and N 2 + ions up to fluences of about 10 17 ions cm -2 . XPS studies showed the actual surface composition and the chemical bonding to be dependent on the nature of the projectile applied, the ion energy, the fluence, the presence or absence of low energy flooding electrons, and the time elapsed between the ion beam treatment steps. Exposure of the ion beam treated samples to ambient air resulted in a strong uptake of oxygen, the attack of which took place predominantly on Si and to a lesser extent on C

The oxidative degradation of silicone rubber surfaces in air plasmas obtained by RF or corona discharges and the subsequent recovery process were studied by X-ray photoelectron spectroscopy (XPS or ESCA). Using relatively short treatment times (5 min), the surface oxygen content was found to increase and that of carbon to decrease. Within 1 day some recovery toward the original composition was observed, but it was far from being complete. Angle-dependent measurements have shown an almost total recovery in the topmost layer. The degree of surface degradation of a solvent-extracted sample was much higher while its recovery was much smaller than the corresponding features of the nonextracted sample. According to GC and GC–MS analyses the extract contained a mixture of cyclic, and, in a minor quantity, linear dimethylsiloxane oligomers. Based on the above results the following steps were proposed for the oxidative damage and the subsequent recovery processes on silicone rubber surfaces: first the majority of surface methyl groups is removed and an oxidized layer containing Si atoms bound to 3 or 4 oxygens appears. The surface is later covered by a very thin (2–3 nm thick) “silicone oil” layer due to migration of low-molecular-weight components from the bulk. This diffusion-controlled migration step plays a more important role in the recovery process than the eventual reorientation of the newly formed polar groups from the surface toward the bulk. The proposed model is discussed in the light of published data. © 1994 John Wiley & Sons, Inc.

IK1, a composite current of inward rectifying K+ ion channels (Kir 2.1, 2.2, 2.3 and possibly TWIK-1, TASK-1) plays a pivotal role in finalizing the repolarization and adjusting/stabilizing the res...

We have explored a new type of experiment in which the beam-induced surface changes of MgO, SiO2, Al2O3, TiO2, V2O5 and MgAl2O4 are determined by XPS after ion bombardment at 2.5 keV with Ar+ or N2+. The initial bombardment, typically with Ar+, led to a combined surface cleaning and loss of O. Although the relative extents of these were difficult to establish, the result was in every case to define the composition in an N-free situation. After a subsequent bombardment with N2+ the O content was distinctly lower than that after Ar+ impact, with the extra O deficiency in each case made up almost exactly by the N addition. For example, Al2O3 evolved from a nominal Al2O2.74 to a nominal Al2O2.20N0.48. The chemical state of this N was predominantly nitride-type, indicative of MN bonds (M, metal). The observed replacement of MO bonds with MN bonds is disfavoured by thermodynamics and this, combined with the already mentioned tendency for the extra O loss to be closely matched by the N addition, together constitute a strong indication that the disturbed lattice is to some extent relaxing randomly. Interestingly, however, the extent by which N replaces O increases as the energy change calculated for this replacement decreases. This confirms, in agreement with a large body of earlier work, that the changes in the oxides are to some extent also chemically guided. The similarity to ion beam mixing and to ion-beam-induced grain growth is worth noting, where again one finds a mixture of ballistic (i.e. random) and chemically guided behaviour.

RF-sputtered CrSiO cermet films deposited without and with a bias (200 V) have been studied by XPS and AES. Samples as deposited, etched by HF solution as well as annealed at temperatures up to 600°C have been considered. XPS results showed that the surface of the as-received samples were depleted in Cr and enriched in O with respect to the target composition. Silicon and Cr were present in both oxidized and reduced forms in the surface layer. Ar+ ion sputter profiles revealed that the composition of the subsurface approached that of the target and that Cr was present in the subsurface in reduced and Si in both oxidized and reduced states. AES in-depth profiling resulted in element concentration trends similar to but element ratios different from those observed by XPS. This was attributed to preferential sputtering coupled with the significantly different sampling depths of the two techniques. Cr3Si was identified by x-ray diffraction in samples treated at 600°C, but not even traces of it could be detected by this method below 400°C. The Si Auger parameter determined by XPS proved to be more sensitive in identifying silicide-type bonds in the CrSiO layers studied.

Under conditions of high temperature, polyimides and their prepolymers undergo a number of chemical transformations, the most part of which relate to reaction of polycondensation. New aspects of thermal cyclodehydration in the presence of heteroaromatic compounds used as stereospecific catalysts were studied. The mechanism of thermal decarboxylation and decarbonylation of polyimides under conditions of heating in inert and self-generating atmosphere was ascertained. A study of the polycondensation processes leading to the formation of ordered domains in polyconjugated products of high temperature thermolysis was carried out. The principal parameters of the thermochemical transformation of the polyimide structure depending on the chemical nature of the polyimide unit were determined by means of the kinetics of the structural changes of the basic fragments of polyimide series. The role of nitrogen atoms in the formation of the turbo-straticulate centres in the products of polyimide thermolysis is discussed. Bei hohen Temperaturen erfolgen in Polyimiden und ihren Prepolymeren eine Reihe chemischer Umwandlungen, die uberwiegend als Polykondensationsreaktionen anzusehen sind. Die thermische Cyclodehydrierung in Gegenwart von als stereospezifische Katalysatoren wirkenden heteroaromatischen Verbindungen wurde untersucht. Der Mechanismus der thermischen Decarboxylierung und Decarbonylierung von Polyimiden beim Erhitzen in inerter und in sich selbst generierender Atmosphare wurde ermittelt. Die Polykondensationsprozesse, die zur Bildung von geordneten Bereichen in den bei der Hochtemperaturthermolyse entstchenden Produkten fuhren, wurden untersucht. Die Parameter der thermochemischen Umwandlung der Polyimidstruktur wurden durch kinetische Untersuchungen in Abhangigkeit von der chemischen Natur der Polyimideinheit bestimmt. Die Bedeutung der Stickstoffatome fur die Bildung graphitahnlicher Zentren in den Thermolyseprodukten der Polyimide wird diskutiert.

We report the prenatal exclusion of partial trisomy in a family with maternal pericentric inversion of chromosome 21 by fluorescence in situ hybridization (FISH). After determining the structural rearrangement in the mother and her affected son with 46,XY,rec(21)dup(21q)inv(21)(p11q22) resulting in Down syndrome (DS), a chorionic villus sample from the current pregnancy was analysed for the copy number of the DS critical region with a cosmid contig. The signal distribution was normal and the cytogenetic analysis revealed that the fetus had inherited the inverted chromosome 21 in a balanced form. FISH probes specific for the DS region are of great value in supporting cytogenetic results, regardless of the structural status of chromosome 21.

On base of polyimides with various chemical structures, which are considered to be the main structure types of polyimides, some carbonized products were obtained. By means of pyrolyse gas chromatography and X-ray photoelectron spectroscopy the chemical changes in the polyimides during heating were studied. A mechanism of the carbonization process is suggested. Ausgehend von Polyimiden mit unterschiedlichen chemischen Strukturen, die als die wichtigsten Strukturtypen von Polyimiden angesehen werden, wurden einige carbonisierte Produkte erhalten. Mit Hilfe der Pyrolyse-Gaschromatographie und Rontgen-Photoelektronen-Spektroskopie wurden die beim Erhitzen der Polyimide ablaufenden chemischen Anderungen verfolgt. Ein Mechanismus fur den Carbonisierungsprozes wird vorgeschlagen.

Thermochemical reactions in solid phase at the synthesis, thermodegradation, and carbonization of polyimides were investigated. Model compounds and model reactions play a significant role in the elucidation of the mechanism of solid state polycondensation reactions. The methods of thermal analysis prove a unique tool for the study of solid state reactions. Die thermochemischen Reaktionen in fester Phase bei Synthese, thermischem Abbau und Carbonisierung von Polyimiden wurden untersucht. Modellverbindungen und Modellreaktionen spielen bei der Aufklarung des Mechanismus der Polykondensationsreaktionen in fester Phase eine wesentliche Rolle. Die thermische Analyse erwies sich als geeignete Methode zur Untersuchung von Festkorperreaktionen.

We report on two sisters with Perrault's syndrome, i.e., autosomal recessive ovarian dysgenesis associated with sensorineural deafness. They were deaf-mute and of normal height with a few minor somatic anomalies. Both had streak gonads and an apparently normal female 46,XX chromosome constitution. The parents were apparently not consanguineous. The mother had normal hearing. Other relatives were not available for study. Epilepsy, which occurred in three relatives including one of the index patients, may have been inherited coincidentally from the mother's family.

The methods of mass-spectrometric thermal analysis, IR spectroscopy, pyrolysis gas chromatography and X-ray photoelectron spectroscopy were used for the investigation of the effect of benzimidazole (BI) on the thermal behaviour of poly(4,4′-oxydiphenylene)-pyromellitamic acid (PAA). It is shown that the formation of a complex of PAA with BI is accompanied by the ordering of amide groups of the polymer, which leads to a decrease in the number of defective units in the resulting polyimide. Mit den Methoden Massenspektrometrie—Thermoanalyse, IR-Spektroskopie, Pyrolyse—Gaschromatographie und Rontgenphotoelektronen-Spektroskopie wurde der Einflus von Benzimidazol (BI) auf das Verhalten von Poly(4,4′-oxydiphenylen)-pyromellitamidsaure (PAA) bei der thermischen Cyclisierung untersucht. Es wird gezeigt, das die Bildung eines Komplexes von PAA mit BI eine Ordnung der Carboxyamid-Gruppen des Polymers bewirkt, was eine Abnahme der Fehlstrukturen in dem resultierenden Polyimid zur Folge hat.

The significance of trisomy 20 mosaicism in cultured amniotic fluid cells is still confusing. We report a case of amniotic cell normal/trisomy 20 mosaicism diagnosed prenatally. The pregnancy was carried to term and a normal baby girl was delivered. The authors consider that in cases of amniotic fluid cell normal/trisomy 20 mosaicism the termination of pregnancy may not be advised, however, the parents should be fully informed.