bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mineral reactions in sulphide systems as indicators of evolving fluid geochemistry – a case study from the Apollo mine, Siegerland, FRG
Authors: Wagner Thomas , Cook Nigel J. 
Published: December 2006

AbstractThe textural and paragenetic relationships of sulphide and sulphosalt minerals within Cu-Pb-Sb-Bi hydrothermal vein mineralization at the Apollo mine, Siegerland, Germany, are interpreted in terms of various reaction sequences. An earlier primary sulphide mineralization hosted within a siderite vein of the Siegerland type, with pyrite, chalcopyrite, sphalerite and galena as main component phases, has been overprinted by Sb-, Bi- and Cu-rich fluids. This superposition resulted in the formation of new quartz-stibnite veins, and various mineral reactions with the primary sulphides including the formation of the sulphosalt minerals semseyite, tetrahedrite, meneghinite, jaskolskiite, boulangerite, bournonite and zinkenite. Based on microprobe analyses of reaction pairs and determination of mineral proportions in some cases, a series of quantitative data for each mineral reaction may be generated. This, in turn, allows for the construction of isocon diagrams permitting the relative mobility and immobility of all chemical elements involved in each reaction to be discussed. Two stages of reactive replacement are identified, characterized by immobile behaviour of S and supply of Sb and Cu during the first stage and relative immobility of S and Sb with no further supply of metals during the second stage. Formation of sulphosalts inside the siderite vein during the first stage is interpreted as a decrease of disequilibrium between hydrothermal fluids and pre-existing vein minerals. Replacement processes of the second stage are interpreted as an equilibration of geochemical contrasts between different points within the siderite vein and also between the siderite and quartz-stibnite vein systems. The geochemical evolution of fluid composition during the entire mineralizing event may therefore be modelled, based on the transfer of chemical components reflected in the succession of mineral reactions. Such an approach has applications to comparable polyphase mineralization sequences, in which an understanding of fluid evolution patterns may greatly assist in the development of genetic models for mineral deposits. Solid-state diffusion and grain-boundary diffusion are considered to be the dominant mechanisms for short-range mass transport, whereas diffusion of ionic and complex species through the fluid is considered to be of major importance in long-range mass transport.
Mineralogical characterization of paulingite from Vinarická Hora, Czech Republic
Authors: Lengauer C. L. , Giester G. , Tillmanns E. 
Published: December 2006

AbstractA sample of the zeolite paulingite from the locality Vinarická Hora was investigated by means of chemical, thermal, powder and single crystal X-ray methods. The fully transparent, colourless to pale yellow crystals exhibit the form {110} and occur together with phillipsite. The chemical composition is (Ca2.57K2.28Ba1.39Na0.38)(Al11.55Si30.59O84)·27H2O, Z = 16 with minor amounts of Mg (<0.05), Sr (<0.13), Mn (<0.01), and Fe (<0.04). The chemical differences from previously described paulingites are a high Ba-content, a lower Si/(Al+Fe) ratio of 2.64, and a reduced water-content. The calculated density is 2.098 g cm−3, and the observed refractive index is 1.482(2). The dehydration behaviour is characterized by a main weight loss from 24–190°C (−11.2 wt.%, ≅ 21H2O) and a minor weight loss from 190–390°C (−3.1 wt.%, ≅ 6H2O). The rehydration capability was proven up to 150°C. The dehydration process during the main weight loss is accompanied by a reduction of the cell volume of 11%. The refined lattice parameters of the X-ray powder data are a a = 35.1231 (5) Å and a = 33.7485(8) Å of an untreated and a dehydrated sample, respectively. A breakdown of the paulingite structure can be observed while the remaining water content decomposes. The single crystal X-ray refinement of this chemically different sample material derived three main cation positions, which are inside a so called paulingite or π-cage (Ca), between 8-rings of neighbouring π-cages (Ba), and in the centre of the non-planar 8-rings of the γ-cage (K). Further partially occupied cation positions (Ca,Na) were located in the planar 8-rings of the α- and γ-cages. No positions within the double 8-membered rings were detected. The water is localized around the main cation positions and in three clusters of partially occupied sites.
Composition of trioctahedral micas in the Karlovy Vary pluton, Czech Republic and a comparison with those in the Coruubian batholith, SW England
Authors: Stone M. , Klomínský J. , Rajpoot G. S. 
Published: December 2006

AbstractTrioctahedral micas in the Karlovy Vary pluton range in composition from Fe-biotites in the granites of the Older Intrusive Complex (OIC) through siderophyllite and lithian siderophyllite to zinnwaldite in the granites of the Younger Intrusive Complex (YIC). Li + AlVI + Si would appear to substitute for Fe2+ + AlIV in biotite with a formula similar to that given in Henderson et al. (1989), but Li + Si appears to substitute for Fe2+ + AlIV in the Li-micas. In mica vs. host rock plots, Rb and F show positive linear covariation except for the Li-mica granites, but femic constituents and tFeO/(tFeO + MgO) have separate trends for OIC and YIC granites and micas. Further differences between OIC and YIC granite micas are seen in their Ti and Mg contents and in plots like V vs. SiO2, AlIVvs. Fe/(Fe+Mg) and Li vs. total iron as Fe2+ and in the results of discriminant analysis. These reveal a geochemical hiatus between OIC and YIC granite micas that coincides with a major temporal hiatus.Biotite compositions in the YIC granites are similar to those in the granites of the Cornubian batholith and reveal a similar magmatic evolution and genesis in which later biotites evolve to lithian siderophyllites with some enrichment in trace alkalis and F. It is suggested that the biotite granites in the YIC were derived from the products of partial fusion of the OIC granites. A less well-marked geochemical hiatus exists between YIC biotites and zinnwaldites. In some plots (e.g. Si vs. Li, Li vs. tFe) apparent continuity between biotite and the Li-micas suggests continuous evolution, but in others (e.g. Rb vs. TiO2, Rb(biotite) vs. Rb(rock)), Li-mica data points stand apart from the biotites suggesting, like the whole rock data, a separate evolution. Comparison with the more abundant data for Li-micas of the Cornubian batholith suggests derivation of the Li-mica granites by partial fusion of the OIC/YIC granite residues.
Jadeite–K-feldspar rocks and jadeitites from northwest Turkey
Authors: Okay Aral I. 
Published: December 2006

AbstractBlueschist-facies rocks with jadeite-K-feldspar-lawsonite paragenesis occur as exotic blocks in Miocene debris flows in the blueschist belt of northwest Turkey. The jadeite-K-feldspar rocks have a very fine grain size and although recrystallized locally retain a relict porphyritic volcanic texture. The former nepheline microphenocrysts, recognized from their characteristic shapes, are pseudomorphed by jadeite and K-feldspar, while the relict magmatic aegirine has rims of jadeite. The matrix of the rock consists of very fine-grained aggregates of jadeite, K-feldspar and lawsonite. In some blocks, jadeite makes up >60% of the mode. Jadeite, K-feldspar and lawsonite in the blocks are essentially pure end-member in composition. P-T estimates for these rocks are 8 ± 2 kbar and 300 ± 50°C. The preserved volcanic texture, relict aegirine and the bulk rock composition indicate that these rocks represent metamorphosed phonolites. The paragenesis in these rocks shows that jadeite-K-feldspar is a stable mineral pair in blueschist-facies P-T conditions.
Omphacite-diopside vein in an omphacitite block from the Osayama serpentinite melange, Sangun-Renge metamorphic belt, southwestern Japan
Authors: Tsujimori Tatsuki 
Published: December 2006

AbstractOmphacite (Jd46.1–52.0Ae0–8.4Aug48.0–51.2) and diopside (Jd4.3–6.3Ae0–0.4Aug93.6–95.6) coexist in a vein cutting an omphacitite block in a serpentinite melange of the Oeyama ophiolite, central Chugoku Mountains. The compositional gap between omphacite and diopside is significantly wider than for other omphacitediopside pairs reported in the literature. The intergrowth texture of the omphacite-diopside vein suggests that the clinopyroxene pair was contemporaneously crystallized in the fracture from a Ca-bearing, alkali-rich fluid in a sub-solvus condition. Such a fluid may have been introduced from the surrounding serpentinized clinopyroxene-bearing harzburgite. The stability of omphacite and Al-rich pumpellyite in the matrix and the omphacite-diopside vein indicate that the earlier matrix recrystallization and later fracture filling may have both taken place under high-P-T condition during the melange-forming stage.
Alkali-deficient tourmaline from the Sullivan Pb-Zn-Ag deposit, British Columbia
Authors: Jiang Shao-Yong , Palmer Martin R. , Slack John F. 
Published: December 2006

AbstractAlkali-deficient tourmalines are found in albitized rocks from the hanging-wall of the Sullivan Pb-Zn-Ag deposit (British Columbia, Canada). They approximate the Mg-equivalent of foitite with an idealized formula □(Mg2Al)Al6Si6O18(BO3)3(OH)4. Major chemical substitutions in the tourmalines are the alkali-defect type [Na*(x) + Mg*(Y) = □(x) + Al(Y)] and the uvite type [Na*(x) + Al(Y) = Ca(x) + Mg*(Y)], where Na* = Na + K, Mg* = Mg + Fe + Mn. The occurrence of these alkali-deficient tourmalines reflects a unique geochemical environment that is either alkali-depleted overall or one in which the alkalis preferentially partitioned into coexisting minerals (e.g. albite).Some of the alkali-deficient tourmalines have unusually high Mn contents (up to 1.5 wt.% MnO) compared to other Sullivan tourmalines. Manganese has a strong preference for incorporation into coexisting garnet and carbonate at Sullivan, thus many tourmalines in Mn-rich rocks are poor in Mn (<0.2 wt.% MnO). It appears that the dominant controls over the occurrence of Mn-rich tourmalines at Sullivan are the local availability of Mn and the lack of other coexisting minerals that may preferentially incorporate Mn into their structures.
Vitamin K–containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7
Authors: Schurgers Leon J. , Teunissen Kirsten J. F. , Hamulyák Karly , Knapen Marjo H. J. , Vik Hogne , Vermeer Cees 
Published: December 2006

Abstract
Vitamin K is a cofactor in the production of blood coagulation factors (in the liver), osteocalcin (in bone), and matrix Gla protein (cartilage and vessel wall). Accumulating evidence suggests that for optimal bone and vascular health, relatively high intakes of vitamin K are required. The synthetic short-chain vitamin K1 is commonly used in food supplements, but recently the natural long-chain menaquinone-7 (MK-7) has also become available as an over-the-counter (OTC) supplement. The purpose of this paper was to compare in healthy volunteers the absorption and efficacy of K1 and MK-7. Serum vitamin K species were used as a marker for absorption and osteocalcin carboxylation as a marker for activity. Both K1 and MK-7 were absorbed well, with peak serum concentrations at 4 hours after intake. A major difference between the 2 vitamin K species is the very long half-life time of MK-7, resulting in much more stable serum levels, and accumulation of MK-7 to higher levels (7- to 8-fold) during prolonged intake. MK-7 induced more complete carboxylation of osteocalcin, and hematologists should be aware that preparations supplying 50 μg/d or more of MK-7 may interfere with oral anticoagulant treatment in a clinically relevant way.
Changes in dietary pattern in 15 year old adolescents following a 4 month dietary intervention with school breakfast – a pilot study
Authors: Ask Anne S , Hernes Sigrunn , Aarek Ingebjørg , Johannessen Gaute , Haugen Margaretha 
Published: December 2006

Abstract

Background
Few studies on impact of meals served in school have been published. However, implications of school meals are an actual issue of both public and political concern in several countries. The objective of this study was to evaluate if breakfast served in a lower secondary school could improve dietary habits and school performance among the students.

Methods
All students in 10th grade in a lower secondary school, consisting of two school classes, were invited to participate in a controlled study. The students in one class were offered a free breakfast at the beginning of each school day for 4 months, while the students in the second class were controls. Both classes were educated in the importance of healthy eating, and a data program enabling them to evaluate dietary intake was introduced. The students answered two questionnaires, one on school performance and one short food frequency questionnaire, four weeks before study start and one week after. Body weight and height were measured by the school nurse at the beginning and end of the study. Because of few students in each group, non-parametrical statistic analyses were used.

Results
All students in the intervention group had breakfast at school during the intervention. One week after the intervention the students in the class who received breakfast had returned to their normal breakfast pattern. In the control group the frequency of a lunch intake had increase, as compared to before study start (p < 0.01). An improved food pattern was seen among the male students in the intervention group, as measured by a healthy eating index after the intervention (p < 0.01). Body Mass Index increased statistically significant in both males and females in the control group (p < 0,01 for males and p < 0.05 for females), but not in the intervention group. Improvement in school performance following school breakfast was not found, but the males in the intervention group reported a significant increase in school contentment (p < 0.05).

Conclusion
In a lower secondary school class served breakfast for 4 months, dietary intake changed to a more healthy profile and weight gain was reduced.
Reduced CD4+ subset and Th1 bias of the human iNKT cells in Type 1 diabetes mellitus
Authors: Kis Janos , Engelmann Peter , Farkas Klara , Richman Geoffrey , Eck Shawn , Lolley James , Jalahej Heyam , Borowiec Maciej , Kent Sally C , Treszl Andras , Orban Tihamer 
Published: December 2006

AbstractInvariant NKT (iNKT) cells are considered to be important in some autoimmune diseases including Type 1 diabetes mellitus (T1DM). So far, the published data are contradictory in regard to the role of iNKT cells in T1DM. We aimed to study iNKT cell frequency and the function of different iNKT cell subgroups in T1DM. We compared the results of four subject groups: healthy (H), long-term T2DM (ltT2DM; more than 1 year), newly diagnosed T1DM (ndT1DM; less than 3 months), and ltT1DM (more than 1 year) individuals. We measured the iNKT cell frequencies by costaining for the invariant TCR α-chain with 6B11-FITC and Vα24-PE. After sorting the Vα24+6B11+ cells, the generated iNKT clones were characterized. We tested CD4, CD8, and CD161 expression and IL-4 and IFN-γ production on TCR stimulation. The CD4+ population among the iNKT cells was decreased significantly in ltT1DM versus ndT1DM, ltT2DM, or H individuals. The T1DM iNKT cell cytokine profile markedly shifted to the Th1 direction. There was no difference in the frequency of iNKT cells in PBMC among the different patient groups. The decrease in the CD4+ population among the iNKT cells and their Th1 shift indicates dysfunction of these potentially important regulatory cells in T1DM.
Intergenomic Epistasis for Fitness: Within-Population Interactions Between Cytoplasmic and Nuclear Genes in Drosophila melanogaster
Authors: Dowling Damian K , Friberg Urban , Hailer Frank , Arnqvist Göran 
Published: December 2006

Abstract
The symbiotic relationship between the mitochondrial and nuclear genomes coordinates metabolic energy production and is fundamental to life among eukaryotes. Consequently, there is potential for strong selection to shape interactions between these two genomes. Substantial research attention has focused on the possibility that within-population sequence polymorphism in mitochondrial DNA (mtDNA) is maintained by mitonuclear fitness interactions. Early theory predicted that selection will often eliminate mitochondrial polymorphisms. However, recent models demonstrate that intergenomic interactions can promote the maintenance of polymorphism, especially if the nuclear genes involved are linked to the X chromosome. Most empirical studies to date that have assessed cytonuclear fitness interactions have studied variation across populations and it is still unclear how general and strong such interactions are within populations. We experimentally tested for cytonuclear interactions within a laboratory population of Drosophila melanogaster using 25 randomly sampled cytoplasmic genomes, expressed in three different haploid nuclear genetic backgrounds, while eliminating confounding effects of intracellular bacteria (e.g., Wolbachia). We found sizable cytonuclear fitness interactions within this population and present limited evidence suggesting that these effects were sex specific. Moreover, the relative fitness of cytonuclear genotypes was environment specific. Sequencing of mtDNA (2752 bp) revealed polymorphism within the population, suggesting that the observed cytoplasmic genetic effects may be mitochondrial in origin.
A Mixed-Model Approach to Association Mapping Using Pedigree Information With an Illustration of Resistance to Phytophthora infestans in Potato
Authors: Malosetti M , van der Linden C G , Vosman B , van Eeuwijk F A 
Published: December 2006

Abstract
Association or linkage disequilibrium (LD)-based mapping strategies are receiving increased attention for the identification of quantitative trait loci (QTL) in plants as an alternative to more traditional, purely linkage-based approaches. An attractive property of association approaches is that they do not require specially designed crosses between inbred parents, but can be applied to collections of genotypes with arbitrary and often unknown relationships between the genotypes. A less obvious additional attractive property is that association approaches offer possibilities for QTL identification in crops with hard to model segregation patterns. The availability of candidate genes and targeted marker systems facilitates association approaches, as will appropriate methods of analysis. We propose an association mapping approach based on mixed models with attention to the incorporation of the relationships between genotypes, whether induced by pedigree, population substructure, or otherwise. Furthermore, we emphasize the need to pay attention to the environmental features of the data as well, i.e., adequate representation of the relations among multiple observations on the same genotypes. We illustrate our modeling approach using 25 years of Dutch national variety list data on late blight resistance in the genetically complex crop of potato. As markers, we used nucleotide binding-site markers, a specific type of marker that targets resistance or resistance-analog genes. To assess the consistency of QTL identified by our mixed-model approach, a second independent data set was analyzed. Two markers were identified that are potentially useful in selection for late blight resistance in potato.
Simulations Provide Support for the Common Disease–Common Variant Hypothesis
Authors: Peng Bo , Kimmel Marek 
Published: December 2006

Abstract
The success of mapping genes involved in complex diseases, using association or linkage disequilibrium methods, depends heavily on the number and frequency of susceptibility alleles of these genes. These methods will be economically and statistically feasible if common diseases are usually influenced by one or a few susceptibility alleles at each locus (common disease–common variant, CDCV, hypothesis), but not so if there is a high degree of allelic heterogeneity. Here, we use forward-time population simulations to investigate the impact of various genetic and demographic factors on the allelic spectra of human diseases, on the basis of two models proposed by Reich and Lander and by Pritchard. Factors considered are more complex demographies, a finite-allele mutation model, population structure and migration, and interaction between disease susceptibility loci. The conclusion is that the CDCV hypothesis holds and that the phenomenon is caused by transient effects of demography (population expansion). As a result, we devise a multilocus generalization of the Reich and Lander model and demonstrate how interaction between loci with respect to their response to selection may lead to complex effects. We discuss the implications for mapping of complex diseases.
Mapping Temporally Varying Quantitative Trait Loci in Time-to-Failure Experiments
Authors: Johannes Frank 
Published: December 2006

AbstractExisting methods for mapping quantitative trait loci (QTL) in time-to-failure experiments assume that the QTL effect is constant over the course of the study. This assumption may be violated when the gene(s) underlying the QTL are up- or downregulated on a biologically meaningful timescale. In such situations, models that assume a constant effect can fail to detect QTL in a whole-genome scan. To investigate this possibility, we utilize an extension of the Cox model (EC model) within an interval-mapping framework. In its simplest form, this model assumes that the QTL effect changes at some time point t0 and follows a linear function before and after this change point. The approximate time point at which this change occurs is estimated. Using simulated and real data, we compare the mapping performance of the EC model to the Cox proportional hazards (CPH) model, which explicitly assumes a constant effect. The results show that the EC model detects time-dependent QTL, which the CPH model fails to detect. At the same time, the EC model recovers all of the QTL the CPH model detects. We conclude that potentially important QTL may be missed if their time-dependent effects are not accounted for.
Hybrid Mitochondrial Plasmids From Senescence Suppressor Isolates of Neurospora intermedia
Authors: Maas M F P M , Hoekstra Rolf F , Debets Alfons J M 
Published: December 2006

Abstract
We analyzed several natural suppressor isolates of the pKalilo-based fungal senescence syndrome of Neurospora intermedia. The pKalilo plasmid did not increase in titer in these isolates. Nor did it show integration “de novo.” In at least two of the senescence suppressor isolates, pKalilo had formed stable recombinants with other mitochondrial elements. pKalilo/mtDNA recombination junctions were complete and appeared to have been formed via a nonhomologous recombination mechanism. Further analysis revealed that pKalilo had recombined a novel, 2.6-kb cryptic mitochondrial retroplasmid, similar to the mitochondrial retroplasmid pTHR1 from Trichoderma harzianum and retroplasmids of the “Varkud” homology group. The recombinant molecules consisted of pKalilo, the novel element, and short intervening stretches of mtDNA. The latter stretches clearly corresponded to “in vivo” mitochondrial cDNA, suggesting that the molecules had formed via the action of a template-switching reverse transcriptase. We discuss how different types of mitochondrial plasmids interact and how their detrimental effect on the host may be suppressed.