Bibliothek

Notizen: In the Western French Massif Central, the Argentat fault is a major structure through which As–Au fluids percolated in the Late Carboniferous along brittle fractures. New petrostructural investigations show that an early ductile normal-dextral faulting, coeval to leucogranite emplacement took place during the Late Visean syncollisional extension of the belt and was accompanied by a hydrothermal event marked by the growth of muscovites whose 40Ar/39Ar ages cluster around 335 Ma. This early fluid channelling is associated with brittle deformation only in the hangingwall of the Argentat fault, whereas ductile deformation is restricted to the footwall. These results provide new evidence for the upper crust implication during the syncollisional extension in the French Massif Central. This study stresses the interest of a detailed multimethod analysis to characterize hydrothermal processes, especially in basement areas where the tectonic, plutonic and metamorphic evolution is polyphased.

Notizen: In situ U–Th–Pb geochronology on monazite using Electron Probe Micro Analyser has been performed on migmatite in the southern French Variscan Massif Central in order to decipher its complex history. After the Early Visean (340 Ma) nappe stacking, the Cévennes area experienced a regional migmatization already dated 330–325 Ma in northern Cévennes. In these rocks two monazite populations are recognized on the basis of petrology texture and geochemistry. The oldest monazite generation that appears as inclusion in K-feldspar is dated at 331 ± 4 Ma. This age complies with that of the crustal melting experienced by the Cévennes metamorphic series. The youngest monazite generation is interstitial and gives an age of 320 ± 5 Ma. A hydrothermal origin, coeval with the peraluminous magmatism that predates the formation of the Late Carboniferous Velay Dome is proposed as a working hypothesis to account for the formation of this second monazite generation.

Notizen: In the north-eastern part of the North China Block, a mafic magmatic belt consisting of mafic–ultramafic rocks and marine sedimentary rocks crops out between the northern Archean Anshan Block and a southern Palaeoproterozoic Block. 40Ar/39Ar amphibole ages around 1.9 Ga from gabbros, and trace element analyses of gabbros, pyroxenite and shale show that these rocks formed along a Palaeoproterozoic active continental margin. The mafic magmatic belt is interpreted as an arc developed above a south-directed subduction zone, which was subsequently overthrust to the north upon the Anshan Archean Block. This study provides a new example agreeing with increasing evidence supporting plate mobility and thrust tectonics during the Palaeoproterozoic. These new insights must be considered with regard to the formation of the North China Block by magmatic accretion and tectonic collision.

Notizen: Abstract The pre-Oligocene structure of southwest Mexico, south of the trans-Mexico volcanic axis, is investigated from Taxco (Guerrero state, abbreviation: Gro) to the Pacific coast. Three volcano-sedimentary units are recognized; from east to west the calc-alkaline Teloloapan, tholeiitic Arcelia and calc-alkaline Zihuatanejo suites. Structural and stratigraphic data show that the Teloloapan volcanic arc, active during ?Late Jurassic and early Cretaceous, was built upon continental basement. The Teloloapan lavas are overlain by the Albian–Cenomanian Morelos platform carbonates and followed by the Upper Cretaceous Mexcala flysch. In contrast, the Arcelia pillow lavas are associated with sandstones and cherts of Albian-?Cenomanian age. The Zihuatanejo arc was also installed upon continental basement and its magmatic activity was in part coeval with Arcelia magmatism. Unlike the almost undeformed Zihuatanejo volcanic rocks, all the other volcanic units are involved in east-vergent thrusting and recumbent folding associated with ductile tectonics, as well as the Late Cretaceous Mexcala flysch overlying the Morelos platform carbonates. Contrasting with previous views, the present results do not support a major mid-Cretaceous thrusting event in the study area. The new geodynamic interpretation proposed here considers that the Arcelia rocks were formed in a marginal basin situated east of the Zihuatanejo arc. Closure of this basin in Paleocene times is responsible for the east vergent thrust tectonics in SW Mexico.

Notizen: A dermal duct tumor which clinically resembled an intradermal nevus and developed on the lower back of a 59-year-old woman is described. The diagnosis could only be reached by microscopic examination. The dermal duct tumor appears to originate from cells with differentiation towards the intradermal portion of the eccrine sweat duct.

Notizen: In 1994, a study of nickel release and allergic contact dermatitis from nickel-plated metals and stainless steels was published in this journal. It was shown that low-sulfur stainless steel grades like AISI 304, 316L or 430 (S〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:01051873:COD113:les" location="les.gif"/〉0.007%) release less than 0.03 μg/cm2/week of nickel in acid artificial sweat and elicit no reactions in patients already sensitized to nickel. In contrast, nickel-plated samples release around 100/μg/cm2week of Ni and high-sulfur stainless steel (AISI 303 - S =0.3%) releases about 1.5 μug/cm2/week in this acid artificial sweat. Applied on patients sensitized to nickel, these metals elicit positive reactions in 96% and 14%, respectively, of the patients. The main conclusion was that low-sulfur stainless sleets like AISI 304, 316L or 430, even when containing Ni, should not elicit nickel contact dermatitis, while metals having a mean corrosion resistance like a high-sulfur stainless steel (AISI 303) or nickel-plated steel should be avoided. The determining characteristic was in fact the corrosion resistance in chloride media, which, for stainless steels, is connected, among other factors, to the sulfur content. Thus, a question remained concerning the grades with an intermediate sulfur content, around 0.03%, which were not studied. They are the object of the study presented in this paper, 3 tests were performed: leaching experiments, dimethylglyoxime and HNO3 spot tests, and clinical patch tests: however, only stainless steels were tested: a low-sulfur AISI 304 and AISI 303 as references and 3 grades with a sulfur content around 0.03%: AISI 304L, AISI 304L added with Ca. AISI 304L + Cu. Leaching experiments showed that the 4 non-resulfurised grades released less than 0.5 μg/cm2/week in acid sweat while the reulfurized AISI 303 released around or more than 0.5 μug/cm2/week. This is explained by the poorer corrosion resistance of the resulfurized grade. Yet all these grades had the same reaction to the DMG test (negative result), which shows again its lack of sensitivity. In contrast, the HNO3 spot test distinguished AISI 303 from the non-resulfurized grades. Clinical patch tests again showed that some patients (4%) were intolerant to AISI 303, while none were intolerant to the other grades. Thus, this study confirms that non-resulfurized stainless steels (S〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:01051873:COD113:les" location="les.gif"/〉0.03%) like Ni-containing 304 and 3D4L should not elicit Ni contact dermatitis, while the resulfurized grades (5 〉 0.1%) should be avoided.

Notizen: peripheral blood cells from forty patients with atopic dermatitis and elevated serum IgE levels were studied by indirect immunofluorescence using monoclonal antibodies OKT3, OKT4, OKT8 to, respectively, human T cells, helper-inducer and suppressor-cytotoxic T cell subsets.Decreased T cells with the suppressor-cytotoxic phenotype, with an abnormal balance between helper and suppressor cell subsets, and decreased peripheral blood T cells counts were found as compared to controls. Results were similar in the three age-matches group (4 months–2 years, 2–15 years, 15–50 years) studied.No correlation could be established between serum IgE levels and the elevated helper/suppressor cell ratios.

Notizen: In a man with a long history of contact dermatitis to Frullania, patch testing to Fruttania ililatata and eamarisci was followed by an acute diffuse leucocytoclaslic vasculitis (Gou-eerot-Ruiter disease). Histoimmunologic and immunologic findings, with the presence of circulating immune complexes and skin deposits of complement C3, C4 and Clq in dermal vessels, were in favour of an immune complex reaction.The role of Frullania in this immune complex vasculitis is discussed; the incidence of such a vasculitis in patients with contact dermatitis is not uncommon, although poorly documented.