This study focuses on concentrations and fractionation of rare earth elements (REE) in a variety of minerals and bulk materials of hydrothermal greisen and vein mineralization in Paleoproterozoic ...monzodiorite to granodiorite related to the intrusion of Mesoproterozoic alkali- and fluorine-rich granite. The greisen consists of coarse-grained quartz, muscovite, and fluorite, whereas the veins mainly contain quartz, calcite, epidote, chlorite, and fluorite in order of abundance. A temporal and thus genetic link between the granite and the greisen/veins is established via high spatial resolution in situ Rb-Sr dating, supported by several other isotopic signatures (δ34S, 87Sr/86Sr, δ18O, and δ13C). Fluid-inclusion microthermometry reveals that multiple pulses of moderately to highly saline aqueous to carbonic solutions caused greisenization and vein formation at temperatures above 200–250°C and up to 430°C at the early hydrothermal stage in the veins. Low calculated ∑REE concentration for bulk vein (15 ppm) compared to greisen (75 ppm), country rocks (173–224 ppm), and the intruding granite (320 ppm) points to overall low REE levels in the hydrothermal fluids emanating from the granite. This is explained by efficient REE retention in the granite via incorporation in accessory phosphates, zircon, and fluorite and unfavorable conditions for REE partitioning in fluids at the magmatic and early hydrothermal stages. A noteworthy feature is substantial heavy REE (HREE) enrichment of calcite in the vein system, in contrast to the relatively flat patterns of greisen calcite. The REE fractionation of the vein calcite is explained mainly by fractional crystallization, where the initially precipitated epidote in the veins preferentially incorporates most of the light REE (LREE) pool, leaving a residual fluid enriched in the HREE from which calcite precipitated. Fluorite occurs throughout the system and displays decreasing REE concentrations from granite towards greisen and veins and different fractionation patterns among all these three materials. Taken together, these features confirm efficient REE retention in the early stages of the system and minor control of the REE uptake by mineral-specific partitioning. REE-fractionation patterns and fluid-inclusion data suggest that chloride complexation dominated REE transport during greisenization, whereas carbonate complexation contributed to the HREE enrichment in vein calcite.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In the deep biosphere, microbial sulfate reduction (MSR) is exploited for energy. Here, we show that, in fractured continental crystalline bedrock in three areas in Sweden, this process produced ...sulfide that reacted with iron to form pyrite extremely enriched in S-34 relative to S-32. As documented by secondary ion mass spectrometry (SIMS) microanalyses, the S-34(pyrite) values are up to +132 parts per thousand V-CDT and with a total range of 186 parts per thousand. The lightest S-34(pyrite) values (-54 parts per thousand) suggest very large fractionation during MSR from an initial sulfate with S-34 values (S-34(sulfate,0)) of +14 to +28 parts per thousand. Fractionation of this magnitude requires a slow MSR rate, a feature we attribute to nutrient and electron donor shortage as well as initial sulfate abundance. The superheavy S-34(pyrite) values were produced by Rayleigh fractionation effects in a diminishing sulfate pool. Large volumes of pyrite with superheavy values (+120 +/- 15 parts per thousand) within single fracture intercepts in the boreholes, associated heavy average values up to +75 parts per thousand and heavy minimum S-34(pyrite) values, suggest isolation of significant amounts of isotopically light sulfide in other parts of the fracture system. Large fracture-specific S-34(pyrite) variability and overall average S-34(pyrite) values (+11 to +16 parts per thousand) lower than the anticipated S-34(sulfate,0) support this hypothesis. The superheavy pyrite found locally in the borehole intercepts thus represents a late stage in a much larger fracture system undergoing Rayleigh fractionation. Microscale Rb-Sr dating and U/Th-He dating of cogenetic minerals reveal that most pyrite formed in the early Paleozoic era, but crystal overgrowths may be significantly younger. The C-13 values in cogenetic calcite suggest that the superheavy S-34(pyrite) values are related to organotrophic MSR, in contrast to findings from marine sediments where superheavy pyrite has been proposed to be linked to anaerobic oxidation of methane. The findings provide new insights into MSR-related S-isotope systematics, particularly regarding formation of large fractions of S-34-rich pyrite.
Previously we observed in male rats that intermittent administration of nicotine (NIC) during the dark phase reduces food intake (FI) by initially decreasing only dark phase meal size. This was ...followed several days later by an increase in dark phase meal frequency such that FI returned to normal, while body weight remained suppressed. Termination of NIC treatment resulted in a modest dark phase hyperphagia. Since some human females use NIC as a weight control drug, the present study investigated changes in FI and body weight regulation in adult female rats treated for five estrous cycles with saline or a 1.40 mg/kg/day (free base) dose of NIC, which was given in four equal i.p. doses during the dark phase. The rats were followed for 15 days after cessation of NIC. Initially both dark and light phase FI were reduced and this was caused by an immediate decrease in dark and light phase meal size; the attenuation of meal size continued after cessation of NIC. On day 7 of NIC, the rats compensated by significantly increasing the number of dark, but not light, phase meals they took. This resulted in a normal 24-h FI, which was caused by a dark phase increase in FI coupled with a continued decrease in light phase FI. Importantly, these changes in meal patterns persisted for some time after termination of NIC. Upon NIC cessation, the NIC group showed no hyperphagia even though their body weight was significantly decreased. These results document that administration of NIC during the dark phase resulted in a reorganization of the microstructure of FI in females rats that resembles, but does not exactly duplicate, that observed in male rats. Like males, long lasting alterations in the microstructure of FI (e.g., meal size and meal number), were noted in female rats for up to 2 weeks after cessation of NIC. These results differ from studies in which NIC was given continuously 24-h per day and indicate that dark phase NIC administration in rats may represent an appropriate model to study the impact of NIC on meal patterns.
The BioKnowledge Library is a relational database and web site (http://www.proteome.com) composed of protein-specific information collected from the scientific literature. Each Protein Report on the ...web site summarizes and displays published information about a single protein, including its biochemical function, role in the cell and in the whole organism, localization, mutant phenotype and genetic interactions, regulation, domains and motifs, interactions with other proteins and other relevant data. This report describes four species-specific volumes of the BioKnowledge Library, concerned with the model organisms Saccharomyces cerevisiae (YPD), Schizosaccharomyces pombe (PombePD) and Caenorhabditis elegans (WormPD), and with the fungal pathogen Candida albicans (CalPD). Protein Reports of each species are unified in format, easily searchable and extensively cross-referenced between species. The relevance of these comprehensively curated resources to analysis of proteins in other species is discussed, and is illustrated by a survey of model organism proteins that have similarity to human proteins involved in disease.
1 Department of Biomedical
Sciences, Baylor College of Dentistry, A Member of The Texas A & M
University System Health Science Center, Dallas, Texas 75246; and
2 Department of Anatomy,
Physiology ...and Cell Biology, School of Veterinary Medicine, and Food
Intake Laboratory, University of California, Davis, California,
95616
Within 3 h of ingesting an imbalanced amino
acid diet (Imb), rats show attenuated intake, which can be
ameliorated by prior administration of the serotonin receptor
antagonist tropisetron (Trop). Earlier work in which the dorsomedial
hypothalamic nucleus (DMN) was electrolytically lesioned (DMNL)
determined that this structure plays a role in the early detection of
and subsequent adaptation to Imb. However, that study did not address
whether cell bodies in the DMN, fibers of passage, or both were
involved in the DMNL response to Imb. In the present investigation in
experiment 1 , rats were given electrolytic DMNL
or a sham operation (Sham). The rats were injected with saline (Sal) or
Trop just before introduction of Imb. By 3 h Sal-DMNL rats consumed
more Imb than did the Sal-Sham rats; intake was normal by 12 h. Trop
enhanced Imb intake, with Trop and DMNL being additive. By
day 4 the DMNL rats were eating and gaining weight less than were Sham rats.
In experiment
2 , DMN cell bodies were destroyed by
ibotenic acid (Ibo). Sal-injected Ibo-lesioned and Sham rats showed
similar food intake depression on Imb; Trop similarly increased Imb
intake in both groups. By day
4 both Ibo-L rats were eating and
gaining weight less than were Sham rats. In
experiment
3 , groups of rats were given knife cuts posterior, lateral, ventral, dorsal, or anterior to the DMN. During the first 3 h of consuming Imb, all cuts except posterior enhanced the intake of Imb. Over the next 24 h the anterior cut group
continued to eat more Imb than did the Sham rats. In
experiment 4 DMNL rats were given novel diets;
the DMNL rats did not display a neophilic response. The data suggest
that fiber tracts that pass through the DMN may be involved in the
early detection of Imb. DMN cell bodies, or fibers of passage, are not
involved in the Trop effect. Finally, DMN cell bodies are necessary for
proper long-term adaptation to Imb.
body weight; serotonin receptors; serotonin receptor blockers; 5-HT 3 ; rat; essential amino acid
deficiency; food intake
The Yeast Proteome Database (YPDtrade mark) has been for several years a resource for organized and accessible information about the proteins of Saccharomyces cerevisiae. We have now extended the YPD ...format to create a database containing complete proteome information about the model organism Caenorhabditis elegans (WormPDtrade mark). YPD and WormPD are designed for use not only by their respective research communities but also by the broader scientific community. In both databases, information gleaned from the literature is presented in a consistent, user-friendly Protein Report format: a single Web page presenting all available knowledge about a particular protein. Each Protein Report begins with a Title Line, a concise description of the function of that protein that is continually updated as curators review new literature. Properties and functions of the protein are presented in tabular form in the upper part of the Report, and free-text annotations organized by topic are presented in the lower part. Each Protein Report ends with a comprehensive reference list whose entries are linked to their MEDLINE s. YPD and WormPD are seamlessly integrated, with extensive links between the species. They are freely accessible to academic users on the WWW at http://www. proteome.com/databases/index.html, and are available by subscription to corporate users.
The 2,4,6‐trinitrobenzenesulfonic acid (TNBS)‐murine model has been used for immunopathogenesis of inflammatory bowel disease. The use of TNBS induces severe colonic inflammation when administered ...intrarectally in mice. The colitis which results from this procedure also presents clinical and histopathological findings common in periodontitis. This study will characterize parameters needed for successful induction of TNBS‐colitis as well as monitoring periodontal disease levels among 20 adult CD1 mice. The experimental groups were given 25 μL gingival injections of TNBS and the sham groups were given 25 μL saline solution (0.9% NaCl) in each quadrant of both maxillary and mandibular arches. Each group received 50 μL of TNBS or saline solution orally thrice weekly and was given both a gel diet in addition to solid mouse pellets. Oral and systemic tissue samples were collected at 2, 4, 6, 10 weeks. Radiographic examinations of both arches were taken to supplement histologic evaluations of changes in tooth supporting structures. Soft tissue samples were obtained from the large intestines and analyzed for the extent of systemic inflammation caused by TNBS. Colitis was present from second week on, with TNBS treatment. Radiographic and histochemical analyses revealed some changes in the alveolar bone pattern. Morphologic changes were noted in the colonic mucosa with extensive inflammatory infiltrates and some ulceration. This novel approach can help elucidate the relationship between alveolar bone loss and systemic manifestation common to gingival and periodontal disease for future therapeutic purposes.
Grant Funding Source: PerioSciences, LLC
Within 3 h of ingesting an imbalanced amino acid diet (Imb), rats show attenuated intake, which can be ameliorated by prior administration of the serotonin receptor antagonist tropisetron (Trop).
Georgy and Vladimir Stenberg, central participants of the Russian avant-garde and the first to use the term "constructivist", were Swedish. Thanks to the first international 'two-person' museum ...exhibition on the Stenberg brothers, in the summer of 1997 at the Museum of Modern Art in New York, interest in their work has been renewed. The focus of the MoMA exhibition was on the film posters. In addition to the Stenbergs' work as constructivists and theatre scenographers, this is the part of their work that has brought them most international fame. There is, however, one aspect which, if mentioned at all, is mentioned only in passing: the Stenbergs were chief designers for the Red Square in Moscow.
In addition to a brief presentation of the Swedish heritage of Vladimir Augustovich (1899 - 1982) and Georgy Augustovich Stenberg (1900 - 1933), the aim of this article is to introduce the Stenbergs as designers for the celebrations in the Red Square. Other key places along the parade route in central Moscow were the Palace of the Soviets and Gorky Park. The Stenberg brothers participated in all three projects. In order to get an idea of what proportions these mass stagings had, I will discuss them in the context of the reconstruction of Moscow into a parade centre, the first five-year plan, and the cultural revolution, all of which took place at the same time as the Stenbergs established themselves as designers for street festivities. First of all, however, I shall give a short background of Georgy and Vladimir Stenberg and their aesthetical standpoints in art.
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