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Future space missions will operate in increasingly hostile environments, such as those in low-perihelion solar orbits and Jovian magnetosphere. This exploration involves the selection of optical materials and components resistant to the environmental agents. The conditions in space are reproduced on ground through the use of ion accelerators. The effects of He particles coming from the solar wind impinging on a gold thin film have been systematically investigated, considering absorbed doses compatible with the duration of the European Space Agency Solar Orbiter mission. Structural and morphological changes have been proved to be dependent not only on the dose but also on the irradiation flux. A predictive model of the variation of thin film reflectance has been developed for the case of lower flux irradiation. The results are discussed regarding reliability and limitations of laboratory testing. The outcomes are important to address the procedures for the space qualification tests of optical coatings.

The localization of charge carriers by electronic repulsion was suggested by Mott in the 1930s to explain the insulating state observed in supposedly metallic NiO. The Mott metal–insulator transition has been subject of intense investigations ever since1–3—not least for its relation to high-temperature superconductivity4. A detailed comparison to real materials, however, is lacking because the pristine Mott state is commonly obscured by antiferromagnetism and a complicated band structure. Here we study organic quantum spin liquids, prototype realizations of the single-band Hubbard model in the absence of magnetic order. Mapping the Hubbard bands by optical spectroscopy provides an absolute measure of the interaction strength and bandwidth—the crucial parameters that enter calculations. In this way, we advance beyond conventional temperature–pressure plots and quantitatively compose a generic phase diagram for all genuine Mott insulators based on the absolute strength of the electronic correlations. We also identify metallic quantum fluctuations as a precursor of the Mott insulator–metal transition, previously predicted but never observed. Our results suggest that all relevant phenomena in the phase diagram scale with the Coulomb repulsion U, which provides a direct link to unconventional superconductivity in cuprates and other strongly correlated materials. A thorough analysis of the optical and transport properties of several two-dimensional organic conductors and insulators with varying on-site correlation strengths and bandwidths led to a quantitative phase diagram for pristine Mott insulators.

The thermal stability of a SiNx passivation layer and its influence on the annealing behavior of an amorphous Ta73Si27 diffusion barrier deposited between copper and SiO2 were analyzed by X-ray diffraction, glow discharge optical emission spectroscopy, Auger electron spectroscopy, scanning electron microscopy, and transmission electron microscopy. During heat treatment at a temperature Tan = 500 °C, diffusion of Cu atoms out of the Cu metallization into the SiNx passivation occurs. The Cu diffusion intensifies with increasing annealing temperature and annealing time and seems to be a necessary precondition for a defect formation process observed within the Cu metallization. Depending on the chemical composition of the SiNx/Cu interface, voids in the μm-range can be formed within the Cu film. Compared to an unpassivated sample, heat treatment leads to a reduced diffusion of Ta atoms from the barrier through the copper into the SiNx/Cu interface. The barrier crystallization process into Ta5Si3 occurring during annealing at Tan = 600 °C is principally not affected by the presence of a SiNx passivation. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Crystallisation and annealing behaviour of two caesium borosilicate glass samples with approximate boroleucite composition were characterised by means of differential scanning calorimetry measurements as well as X-ray powder diffraction investigations with subsequent profile fitting of the observed patterns according to the Rietveld and/or Pawley method. While one sample crystallised primarily in an orthorhombic phase (a= 6.592(3) Å, b= 11.825(5) Å, c= 12.620(6) Å; possible space groups: Pmc21((26), setting: P21am), Pma2 (28) and Pmma((51), setting: Pmam)) which has been unknown until now and transformed irreversibly into the well-known cubic boroleucite phase at T≈ 850 °C, cubic caesium boroleucite (space group: Ia3̅d(230)) was crystallised directly from the other sample. In this case, the orthorhombic phase was metastable. At the onset temperature of glass crystallisation Tx, on= 770 °C, it existed only for about 75 min. The change of the lattice parameter aof the cubic unit cell of caesium boroleucite in the course of the thermal treatments was explained by the alteration of the size of the TO4tetrahedra (T = Si, B).

SummaryCutaneous T-cell lymphomas represent a group of malignant lymphoproliferative disorders characterised by the occurrence of a monoclonal population of T-lymphocytes. Diagnosis of early stages of this disease is a difficult challenge for both the dermatologist and the dermatopathologist. With the aid of the polymerase chain reaction it is possible to amplify specific regions of the T-cell receptor gamma gene. The amplification products can then be separated by denaturing gradient gel electrophoresis in order to detect a monoclonal population of T-lymphocytes in the infiltrate. We studied 4 patients with the clinicopathologic diagnosis of mycosis fungoides and 2 patients diagnosed as large plaque parapsoriasis. A monoclonal population was detected in 3 of the 4 mycosis fungoides cases and in 1 of the patients with large plaque parapsoriasis. This indicates that our analysis can help us establishing a diagnosis, and it can also help us to identify patients with a possible early stage of the disease, which clinically or histologically is not yet recognised as such.

Background Gradual telomere erosion eventually limits the replicative life span of somatic cells and is regarded as an ultimate tumour suppressor mechanism, eliminating cells that have accumulated genetic alterations. Telomerase, which has been found in over 85% of human cancers, elongates telomeres and may be required for tumorigenesis by the process of immortalisation. Malignant mesothelioma is an incurable malignancy with a poor prognosis. The disease becomes symptomatic decades after exposure to carcinogenic asbestos fibres, suggesting the long term survival of pre-malignant cell clones. This study investigated the presence of telomerase in pleural malignant mesothelioma, which may be the target for future anti-telomerase drugs. Methods Telomerase activity was semi-quantitatively measured in extracts from 22 primary pleural mesotheliomas, two benign solitary fibrous tumours of the pleura, four mesothelioma cell lines, and six short term mesothelial cell cultures from normal pleura using a non-isotopic dilution assay of the telomeric repeat amplification protocol. Results Twenty of the 22 primary mesotheliomas (91%) and all tumour derived mesothelioma cell lines were telomerase positive. Different levels of enzyme activity were observed in the tumours of different histological subtypes. Telomerase activity could not be detected in the six normal mesothelial cell cultures or in the two mesotheliomas. Both benign solitary fibrous tumours showed strong telomerase activity. Conclusions Telomerase activity is found in a high proportion of mesotheliomas and anti-telomerase drugs might therefore be useful clinically. The results are consistent with the hypothesis that telomerase activity may be a feature of carcinogenesis in mesotheliomas and possibly in many other cancers.

Summary In connection with the fact that BB rats are homogeneous for haplotype RTlu and their parental Wistar rat stock is heterogenous for haplotypes RTlu and RTla the influence of the RTl haplotypes on some hematologic and metabolic traits was studied. The findings indicate marked differences between BB rats and their parental strain independent of haplotype RTl so that the changed genetic background of the BB rat rather than the haplotype per se seems to be the reason for the differences observed.

The mean spherical approximation (MSA) has proved to be a very general and flexible method to analyze equilibrium statistical mechanical systems. In this note we test its accuracy against a simple one-dimensional model, i.e., a lattice gas of polarizable molecules where the internal degree of freedom is treated as quantized harmonic oscillators which interact via harmonic forces. This model can be solved exactly. We find a very good agreement between the MSA and exact solutions.

Summary Primary roots of maize seedlings have been treated with solutions of lanthanum and lead salts in an attempt to demonstrate endocytosis. Subsurface cells in the root cap reveal deposits of these heavy metals in coated pits in the plasma membrane and in coated vesicles. In addition lead deposits were observed in coated evaginations (pits) on large (secretory) vesicles present at the trans-pole of the Golgi apparatus and on small vacuoles. Lead was also found in the peripheral regions of individual cisternae throughout the dictyosomal stack. We interpret our results as providing evidence for coated pit/coated vesicle-mediated endocytosis and for the direct recycling of plasma membrane to the Golgi apparatus.

Like other hedgehog species investigated hitherto, also the Middle African species Atelerix albiventris has a diploid number of 48 chromosomes. However, Aethechinus and Atelerix display quite distinct cytogenetic characteristics compared to the hedgehog genera Erinaceus, Hemiechinus and Paraechinus. Individual chromosome structures and reactivities permit the recognition of similarities to the Algerian hedgehog Aethechinus algirus and indicate their close relationship.

The present status of Robertsonian karyotype variation in populations of wild mice from Belgium is presented. Two fusions, Rb(4.12)1Nam and Rb(5.10)3Nam, were identified in the central plain of this flat country. Surrounding this region only mice with the usual 2n=40 karyotype occurred. From the distribution pattern some possible relationships to other Rb populations from Europe are discussed.

An analysis of the temperature variation of different moments of electronic absorption and emission bands of defects is given. The relaxation around a lattice defect and the changes of the force constants during an electronic transition are calculated. A Green's function formulation of the single moments allows a compact description of the coupling of all lattice oscillators to the electronic transition by perturbed projected phonon densities. The range of perturbed shells of ions around the defect can easily be adapted to the special model of the center. A numerical discussion forF-centers in KBr gives simultaneously the experimentally observed Stake's shift and half width of the bands for fairly reasonable values of the relaxation parameters (lattice ion displacements and force constants). A plausible explanation is found for the wellknown discrepancy of the effective frequencies which define the temperature behaviour of the half widths in absorption and emission.

Zusammenfassung Im Laufe eines 3/4 Jahres wurde bei 93 Patienten mit chronischer Emphysembronchitis und bei 27 Patienten mit rezidivierenden Magen- und Duodenalulcera der Fingerabdrucktest nachShwachman undGahm durchgeführt. Diese einfache Methode der Schweißelektrolytbestimmung ermöglicht ohne quantitative Analyse in einem großen Teil der Fälle durch das eindeutig positive Testergebnis eine Aussage im Sinne der Erhöhung des Elektrolytgehaltes über die Norm. Damit bedeutet dieses Verfahren, das bei positivem Ausfall auf das Vorliegen einer Mucoviscidosis hinweist, für die Klinik eine Bereicherung im Sinne einer Suchreaktion, ohne allerdings die quantitative Elektrolytbestimmung im Schweiß ersetzen zu können. Auch bei Begutachtungen kann sich der Fingerabdrucktest in diesem Sinne nützlich erweisen.