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Fluornatromicrolite is a new mineral species of the pyrochlore supergroup (microlite group), with fluorine dominant at the second anion site. The type locality is the Alto Quixaba granitic pegmatite near Quixaba village, municipality of Frei Martinho, Paraiba, Brazil. Fluornatromicrolite forms adamantine green regular to flattened octahedral crystals in albite. The streak is white, the Mohs hardness is 5, and the calculated density is 6.568 g/cm 3 . The chemical composition is (Na 1.10 Ca 0.64 Bi 0.15 ) Ta 2.00 O 5.91 F 1.02 , or, ideally (Na,Ca,Bi) 2 Ta 2 O 6 F. The mineral is cubic, space group Fd 3 m , with a 10.4451(2) A, V 1139.56(8) A 3 and Z = 8. The crystal structure was refined to R = 0.034 using 2861 reflections obtained with Mo K α radiation on a four-circle automatic diffractometer. The structure is built up of TaO 6 octahedra and (Na,Ca,Bi)O 6 F 2 polyhedra. The (Na,Ca,Bi)–F distances are significantly shorter than the (Na,Ca,Bi)–O distances.

Abnormalities in the white matter microstructure of the attentional system have been implicated in the aetiology of attention deficit hyperactivity disorder (ADHD). Diffusion tensor imaging (DTI) is a promising magnetic resonance imaging (MRI) technology that has increasingly been used in studies of white matter microstructure in the brain. The main objective of this work was to perform an exploratory analysis of white matter tracts in a sample of children with ADHD versus typically developing children (TDC). For this purpose, 13 drug-naive children with ADHD of both genders underwent MRI using DTI acquisition methodology and tract-based spatial statistics. The results were compared to those of a sample of 14 age- and gender-matched TDC. Lower fractional anisotropy was observed in the splenium of the corpus callosum, right superior longitudinal fasciculus, bilateral retrolenticular part of the internal capsule, bilateral inferior fronto-occipital fasciculus, left external capsule and posterior thalamic radiation (including right optic radiation). We conclude that white matter tracts in attentional and motor control systems exhibited signs of abnormal microstructure in this sample of drug-naive children with ADHD.

Nanowires of an iodine containing Pb–Sb-sulfosalt have been synthesized by chemical vapor transport. Their structure was studied using high-resolution transmission electron microscopy and X-ray powder diffraction. The lattice parameters show values equal to a=4.9801(4) nm, b=0.41132(8) nm (with two-fold superstructure), c=2.1989(1) nm and β=99.918(6)°. These parameters and the results of a multislice simulation are in good agreement with the mineral pillaite, Cu0.10Pb9.16Sb9.84S22.94Cl1.06O0.5 (space group C 2 / m , a=4.949(1) nm, b=0.41259(8) nm, c=2.1828(4) nm, and β=99.62(3)°). Microprobe and EDX analyses yielded a chemical composition of Cu0.507(5)Pb8.73(9)Sb8.15(8)I1.6S20.0(2) which is close to natural pillaite but contains no oxygen and iodine instead of chlorine. The structure of the investigated material is based on chains of M–S polyhedra (M=Pb or Sb) typical for the architecture of sulfosalts implying iodine atoms in trigonal prismatic coordination with Pb atoms from the M–S polyhedra of neighboring chains. The [010] superstructure of the specimen was found to be unstable under electron beam irradiation with a rapid decrease of the b lattice parameter from 0.8 to 0.4 nm within 5 min.

During terminal differentiation of keratinocytes the expression of various proteins, which are required for the formation of the epidermal water barrier in the skin of land dwelling animals, is upregulated. Using a cell culture model for the differentiation of human keratinocytes and real-time PCR, we quantified the mRNA levels of several proteins involved in differentiation and ceramide metabolism. A calcium shift (1.1 mM CaCl2, 10 microM linoleic acid) for 8 days triggered an increase in mRNA levels of keratin 10 (75-fold), profilaggrin (55-fold), glucosylceramide synthase (40-fold), beta-glucocerebrosidase (30-fold), prosaposin (15-fold), acid sphingomyelinase (5-fold), and serine palmitoyltransferase (SPTLC2, 4-fold). However, mRNA levels of keratin 14 and acid ceramidase did not change significantly. On the other hand nitric oxide added at concentrations lower than 0.25mM stimulates proliferation of keratinocytes (Krischel et al., J. Invest. Dermatol. 111, 286-291, 1998). Accordingly, the NO donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP, 0.2 mM) had no effect on the morphology of cultured keratinocytes, whereas in cultured human fibroblasts apoptosis was induced. The expression patterns obtained suggest that keratinocytes remain in a basal proliferative state, with a 3-fold increase in keratin 14 expression, a marked decrease in mRNA levels of differentiation markers and of most ceramide-metabolizing enzymes to negligible levels. The inhibitor of the NO synthase, N(G)-nitro-L-arginine-methyl ester (L-NAME, 10 mM), induced a transient increase in ceramide formation, followed by apoptosis in keratinocytes but not in fibroblasts. Both, SNAP and L-NAME, decreased the mRNA levels of all proteins involved in ceramide metabolism.

Epidermal keratinocytes are exposed to a low water concentration at the stratum corneum-stratum granulosum interface. When epithelial tissues are osmotically perturbed, cellular protection and cell volume regulation is mediated by accumulation of organic osmolytes such as taurine. Previous studies reported the presence of taurine in the epidermis of several animal species. Therefore, we analyzed human skin for the presence of the taurine transporter (TAUT) and studied the accumulation of taurine as one potential mechanism protecting epidermal keratinocytes from dehydration. According to our results, TAUT is expressed as a 69 kDa protein in human epidermis but not in the dermis. For the epidermis a gradient was evident with maximal levels of TAUT in the outermost granular keratinocyte layer and lower levels in the stratum spinosum. No TAUT was found in the basal layer or in the stratum corneum. Keratinocyte accumulation of taurine was induced by experimental induction of skin dryness via application of silica gel to human skin. Cultured human keratinocytes accumulated taurine in a concentration- and osmolarity-dependent manner. TAUT mRNA levels were increased after exposure of human keratinocytes to hyperosmotic culture medium, indicating osmosensitive TAUT mRNA expression as part of the adaptation of keratinocytes to hyperosmotic stress. Keratinocyte uptake of taurine was inhibited by beta-alanine but not by other osmolytes such as betaine, inositol, or sorbitol. Accumulation of taurine protected cultured human keratinocytes from both osmotically induced and ultraviolet-induced apoptosis. Our data indicate that taurine is an important epidermal osmolyte required to maintain keratinocyte hydration in a dry environment.

Butyltins are widely used biocides and accumulate in the food chain. Tributyltin is an imposex-inducing endocrine disrupter in animals. Imposex is characterized by the development of additional male sex organs on females. In a previous study, we identified tributyltin as an inhibitor of human cytochrom P450 aromatase activity. The present work focuses on the impact of butyltins on human androgen metabolism. Activation of androgens is mediated by two human 5alpha-reductase isoenzymes. 5alpha-Reductase type 1 was completely inhibited by tributyltin chloride (IC50=19.9 microM) and dibutyltin dichloride (IC50=32.9 microM), whereas 5alpha-reductase type 2 was only inhibited by tributyltin chloride (IC50=10.8 microM). Both isoenzymes were not affected by tetrabutyltin or monobutyltin indicating that at least two butyl groups bound to the positively charged Sn are required for the interaction of butyltins with the enzymes. Tributyltin inhibited 5alpha-reductase type 1 competitively whereas an irreversible inhibition was evident for the type 2 isoenzyme. In contrast to the distinct effects on 5alpha-reductases, reductive brain 17beta-hydroxysteroid dehydrogenase activity was not inhibited by any butyltin. Insufficient activation of androgens is responsible for developmental disorders of the male reproductive system such as hypospadias. At pharmacologic levels butyltins might contribute to the onset of developmental disorders of the male reproductive system. At present, however, it is unknown whether these levels are reached after acute or chronic exposure to butyltins.

Ronneburgite is a new chain vanadate mineral from Ronneburg, Thuringia, Germany. It occurs as reddish-brown crystals of equant, flattened, or short prismatic habit, up to 0.5 mm in length. The crystals have an adamantine luster and are translucent. Ronneburgite is biaxial negative with refractive indices n α = 1.925(5), n β = 1.960(10), n γ = 1.988(4), and 2 V x = 82°. Electron microprobe analysis (K 2 O = 16.93, MnO = 12.44, MgO = 0.62, V 2 O 5 = 68.54; total = 98.53 wt%) gives the empirical formula K 1.91 Mn 0.93 Mg 0.08 V 4.00 O 11.96 , which simplifies to K 2 MnV 4 O 12 . Ronneburgite is mono-clinic, space group P 2 1 / n , with a = 8.183(3), b = 9.247(3), c = 8.651(2) A, and β = 109.74(2)°. The measured density is 2.84 g/cm 3 ; the calculated density for Z = 2 is 2.85 g/cm 3 . Single-crystal X-ray structure determination (R 1 = 0.046 for 1846 reflections) shows that ronneburgite contains infinite vierer-single metavanadate chains [(VO 3 ) n ] n− of corner-sharing VO 4 tetrahedra along [101]. Although the empirical formula and calculated bond valences indicate that V is 5+ and Mn is 2+, the crystal color, a “poor” structural compatibility index, and Mn-O distances between those expected for Mn 2+ -O and Mn 3+ -O indicate that some Mn 3+ and V 4+ ions are present. K + ions and octahedral Mn n+ ions bridge between the metavanadate chains by coordinating to their oxygen atoms.

Recently, we established keratin 10-deficient mice, serving as a model for the hyperkeratotic skin disorder epidermolytic hyperkeratosis. The considerable ichthyosis in these mice suggested alterations in terminal differentiation and in the formation of a functional epidermal barrier. Here, we report on the ultrastructural organization and composition of the stratum corneum lipids and on the expression of two major cornified envelope proteins. Electron microscopy of ruthenium tetroxide postfixed skin samples demonstrated a normal extrusion and morphology of lamellar bodies as well as the formation of bona fide lamellar layers in neonatal keratin 10-deficient mice. When we studied the composition of the major stratum corneum lipids, however, we found significant changes. Most importantly, the analysis of ceramide subpopulations revealed that the total amount of ceramide 2 was elevated in keratin 10-deficient mice, whereas ceramides 1, 3, 4, and 5 were decreased among total stratum corneum lipids. The amount of the ceramide precursors sphingomyelin and glucosylceramide was reduced in the stratum corneum without accompanying changes in the mRNA coding for acid sphingomyelinase. Notably, we found an increased mRNA and protein content for involucrin in neonatal keratin 10-deficient mice, whereas the expression of loricrin was not changed. Our data demonstrate that, although the formation of lipid layers in the stratum corneum appeared to be normal, its lipid composition is significantly altered in keratin 10-deficient mice.

The zonation, exsolution and replacement phenomena occurring in natural sphalerites and known as the «chalcopyrite disease» were experimentally simulated by solid-state diffusion studies using (Zn,Fe)S crystals as receptors and CuInS 2 , CuFeS 2 , Cu 5 FeS 4 , Cu 2−x S and CuS as metal sources, at temperatures between 400 and 750°C. Therefore, the expression «diffusion-induced segregations» (DIS) is proposed instead of «disease». The driving force for the diffusion is a chemical-potential gradient between the sphalerite crystal (receptor) and the surrounding sulphide powders (diffusion source). Diffusion coefficients of (Cu + In) in ZnS were experimentally determined. The nature of the DIS phases (intermediate solid solution, chalcopyrite, bornite, digenite) and the corresponding textures (dusty, blebs, worm-like, water-melon) depend on the Fe content of the sphalerite, time, temperature, Cu:Fe ratio in the diffusion source, and the sulphur fugacity. General rules for DIS phenomena are deduced from the experimental results and compared to natural occurrences. All the natural «disease» textures of Cu-rich phases in sphalerite can be reproduced by our experiments

Serrabrancaite is a new manganese phosphate from the Alto Serra Branca pegmatite near Pedra Lavrada, Paraiba, Brazil. The mineral occurs as dark brown to dark greenish black isometric crystals up to 0.3 mm size. The crystals have an adamantine luster and are translucent. Chemical analysis yields (in wt%) Mn2O3 = 46.85, P2O5 = 42.72, H2O = 9.8, total = 99.37. The empirical formula is Mn0.98P1.00O3.98·0.90 H2O, simplified to MnPO4·H2O. Serrabrancaite is monoclinic, space group C 2/ c , with unit-cell parameters a = 6.914(2), b = 7.468(2), c = 7.364(2) A, β = 112.29(3)°, V = 351.8(1) A3. The measured density is 3.17(1) g/cm3, the calculated density for Z = 4 is 3.16 g/cm3. Serrabrancaite is isostructural with the sulfates of the kieserite group. The mineral is an alteration product from a phosphate pegmatite and is accompanied by vernadite and phosphosiderite.

Epidermal differentiation results in the formation of the extracellular lipid barrier in the stratum corneum, which mainly consists of ceramides, free fatty acids, and cholesterol. Differentiating keratinocytes of the stratum granulosum synthesize a series of complex long-chain ceramides and glucosylceramides with different chain lengths and hydroxylation patterns at intracellular membranes of the secretory pathway. Formation of complex extracellular ceramides parallels the transition of keratinocytes from the stratum granulosum to the stratum corneum, where their precursors, complex glucosylceramides and sphingomyelin, are secreted and exposed to extracellular lysosomal lipid hydrolases. Submerged cultures used so far showed a reduced ceramide content compared to the native epidermis or the air-exposed, organotypic culture system. In order to investigate the sphingolipid metabolism during keratinocyte differentiation, we optimized a simple cell culture system to generate the major barrier sphingolipids. This optimized model is based on the chemically well-defined serum-free MCDB medium. At low calcium ion concentrations (0.1mM), keratinocytes proliferate and synthesize mainly Cer(NS) and a small amount of Cer(NP). Supplementation of the MCDB cell culture medium with calcium ions (1.1mM) and 10 microM linoleic acid triggered differentiation of keratinocytes and synthesis of a complex pattern of free and covalently bound ceramides as found in native epidermis or air-exposed organotypic cultures, though at a reduced level. The mRNA levels of the differentiation markers keratin 10 and profilaggrin increased, as well as those of ceramide glucosyltransferase and glucosylceramide-beta-glucosidase. The described culture system was thus suitable for biochemical studies of the sphingolipid metabolism during keratinocyte differentiation. The addition of serum or vitamin A to the medium resulted in a decrease in ceramide and glucosylceramide content. Lowering the medium pH to 6, while maintained cell viability, led to an increase in the processing of probarrier lipids glucosylceramide and sphingomyelin to free ceramides and protein-bound ceramide Cer(OS).

Epidermal barrier function to water loss is maintained by lipid membrane domains located in the interstices of the stratum corneum. Exposure of the epidermis to a dry environment or UV irradiation stimulates barrier lipid synthesis and accumulation of the organic osmolyte taurine in the outermost granular keratinocyte layer. In this work we studied a possible relationship between these two different epidermal responses to environmental challenges. As a model system we selected anionic surfactant-induced barrier perturbation. Incubation of reconstructed epidermis with taurine inhibited cytotoxic and proinflammatory effects induced by sodium dodecyl sulfate including (i) a decrease in interleukin-1 alpha and prostaglandin E2 release, (ii) stabilization of keratinocyte membrane integrity, and (iii) improvement of keratinocyte viability. Repeated exposure of human skin to sodium dodecyl sulfate induced an increase in transepidermal water loss, inflammation, and hyperplasia. Topical application of taurine significantly decreased transepidermal water loss after repeated exposure to sodium dodecyl sulfate. Moreover, taurine significantly stimulated the synthesis of all three classes of barrier lipids (ceramides, cholesterol, and fatty acids) in reconstructed epidermis. In conclusion, our data suggest a role for taurine in preventing surfactant-induced dry and scaly skin by modulating the proinflammatory response and stimulating epidermal lipid synthesis.

Recent studies have provided new insights into the occurrence, causes, and pathogenetic consequences of changes in the skin pH in atopic dermatitis, particularly with respect to skin barrier function and colonization with Staphylococcus aureus. Growing evidence suggests an impaired release of proton donors, such as amino acids, urocanic acid, and lactic acid, to the stratum corneum in atopic dermatitis, as a result of reductions in filaggrin proteolysis and sweat secretion. In addition, an impaired formation of free fatty acids from sebaceous lipids and epidermal phospholipids seems to be involved. Because both lipid organization and lipid metabolism in the stratum corneum requires an acidic pH, these alterations might contribute to the disturbance of skin barrier function observed in atopic dermatitis. Furthermore, bacterial growth and virulence of S. aureus, as well as defensive host mechanisms, have increasingly been delineated as pH dependent, giving rise to a new understanding of the pathophysiology underlying increased skin colonization seen in atopic dermatitis.

Over the repository lifetime, the waste package containment barriers will perform various functions that will change with time. During the operational period, the barriers will function as vessels for handling, emplacement, and waste retrieval (if necessary). During the years following repository closure, the containment barriers will be relied upon to provide substantially complete containment, through 10,000 years and beyond. Following the substantially complete containment phase, the barriers and the waste package internal structures help minimize release of radionuclides by aqueous- and gaseous-phase transport. These requirements have lead to a defense-in-depth design philosophy. A multi-barrier design will result in a lower breach rate distributed over a longer period of time, thereby ensuring the regulatory requirements are met. The design of the Engineered Barrier System (EBS) has evolved. The initial waste package design was a thin walled package, 3/8 inch of stainless steel 304, that had very limited capacity, (3 PWR and 4 BWR assemblies) and performance characteristics, 300 to 1,000 years. This design required over 35,000 waste packages compared to today's design of just over 10,000 waste packages. The waste package designs are now based on a defense-in-depth/multi-barrier philosophy and have a capacity similar to the standard storage and rail transported spent nuclear fuel casks. Concurrent with the development of the design of the waste packages, a comprehensive waste package materials testing program has been undertaken to support the selection of containment barrier materials and to develop predictive models for the long-term behavior of these materials under expected repository conditions. The testing program includes both long-term and short-term tests and the results from these tests combination with the data published in the open literature are being used to develop models for predicting performance of the waste packages.

The epidermal permeability barrier for water is essentially maintained by extracellular lipid membranes within the interstices of the stratum corneum. Ceramides, the main components of these membranes, derive in large part from hydrolysis of glucosylceramides mediated by the lysosomal enzyme beta-glucocerebrosidase. As analyzed in this work, the beta-glucocerebrosidase deficiency in type 2 Gaucher mice (RecNci I) resulted in an accumulation of all epidermal glucosylceramide species accompanied with a decrease of the related ceramides. However, the levels of one ceramide subtype, which possesses an alpha-hydroxypalmitic acid, was not altered in RecNci I mice suggesting that the beta-glucocerebrosidase pathway is not required for targeting of this lipid to interstices of the stratum corneum. Most importantly, omega-hydroxylated glucosylceramides which are protein-bound to the epidermal cornified cell envelope of the transgenic mice accumulated up to 35-fold whereas levels of related protein-bound ceramides and fatty acids were decreased to 10% of normal control. These data support the hypothesis that in wild-type epidermis omega-hydroxylated glucosylceramides are first transferred enzymatically from their linoleic esters to proteins of the epidermal cornified cell envelope and then catabolized to protein-bound ceramides and fatty acids, thus contributing at least in part to the formation of the lipid-bound envelope.

The epidermal permeability barrier is maintained by extracellular lipid membranes within the interstices of the stratum corneum. Ceramides, the major components of these multilayered membranes, derive in large part from hydrolysis of glucosylceramides mediated by stratum corneum beta-glucocerebrosidase (beta-GlcCerase). Prosaposin (pSAP) is a large precursor protein that is proteolytically cleaved to form four distinct sphingolipid activator proteins, which stimulate enzymatic hydrolysis of sphingolipids, including glucosylceramide. Recently, pSAP has been eliminated in a mouse model using targeted deletion and homologous recombination. In addition to the extracutaneous findings noted previously, our present data indicate that pSAP deficiency in the epidermis has significant consequences including: 1) an accumulation of epidermal glucosylceramides together with below normal levels of ceramides; 2) alterations in lipids that are bound by ester linkages to proteins of the cornified cell envelope; 3) a thickened stratum lucidum with evidence of scaling; and 4) a striking abnormality in lamellar membrane maturation within the interstices of the stratum corneum. Together, these results demonstrate that the production of pSAP, and presumably mature sphingolipid activator protein generation, is required for normal epidermal barrier formation and function. Moreover, detection of significant amounts of covalently bound omega-OH-GlcCer in pSAP-deficient epidermis suggests that deglucosylation to omega-OH-Cer is not a requisite step prior to covalent attachment of lipid to cornified envelope proteins.

Fe1.8Ni1.2P8, tetragonal, I4 (No. 82), a = 9.085(5) A, c = 4.481(3) A, V = 369.8 A 3 , Z =8 ,Rgt(F) = 0.037, wRref(F 2 ) = 0.086, T = 293 K. Source of material Single crystals of the phosphides from “Orange River” were obtained by using a solution with HNO3 (3%) and methanol. After dissolving the meteorite samples only sulphides, carbides, oxides, phosphides and other crystals remained. The solution with the crystals was filtered and the phosphides were picked up from thefiltermaterial.Theywerepreparedandfixedonglasfibresfor X-ray experiments. The chemical composition was determined by electron microprobe analysis (Cameca SX 100). The crystals are homogeneous and don’t show zonations, twinnings or intergrowth sections. Discussion The (Fe,Ni)3P single crystals (xenomorph variant named Schreibersite) from the “Orange River” meteorite with a Fe:Ni-ratioof1.5:1(Fe1.8Ni1.2P)showabodycenteredtetragonal crystal structure with the well known space group I4 typical for meteoritic phosphides. The distribution of Fe and Ni on the three symmetryindependentmetalpositionswasdeterminedearlieron Rhabdites from “North Chile” meteorite using a Co-tube with a wavelength near by the Fe absorption edge. This result showed thatNipreferstheM2andM3sitesavoidingM1[1](cf.also[2]). Additional measurements with synchrotron radiation (HASYLAB at DESY, Hamburg) near the Fe absorption edge in order to separate Fe and Ni using the anomalous dispersion and thedeltasynthesis[3,4]showedthesameordering:Feprefersthe M1 and M2 sites whereas Ni prefers the M2 and M3 sites. Considering this fact, the site occupancy factors of the Fe and Ni atomswerefixedduringrefinement[5].ThebestR-valueisevoked by a distribution with Fe on M1, Fe/Ni on M2 and Ni on M3.

Lead concentrations and lead isotope ratios were analyzed in two firn/ice cores covering the period from 1650 to 1994, which were obtained from the 4450 m high glacier saddle Colle Gnifetti located in the Monte Rosa massif at the Swiss-Italian border. This study presents the first glaciochemical time series with annual resolution, spanning several centuries of lead concentrations and lead isotopic compositions in precipitation in Europe. Lead concentrations in firn dated from the 1970s are approximately 25 times higher than in ice dated from the 17th century, confirming the massive rise in lead pollution in Europe during the last few centuries. A decline of the lead concentration is then observed during the last two decades, i.e., from 1975 to 1994. The lead isotope ratio 206Pb/207Pb decreased from about 1.18 in the 17th and 18th centuries to about 1.12 in the 1970s. These variations are in good agreement with available information on variations in anthropogenic lead emissions from West European countries, especially from the use of lead additives in gasoline.