816 research outputs found
Majorana spinors and extended Lorentz symmetry in four-dimensional theory
An extended local Lorentz symmetry in four-dimensional (4D) theory is
considered. A source of this symmetry is a group of general linear
transformations of four-component Majorana spinors GL(4,M) which is isomorphic
to GL(4,R) and is the covering of an extended Lorentz group in a 6D Minkowski
space M(3,3) including superluminal and scaling transformations. Physical
space-time is assumed to be a 4D pseudo-Riemannian manifold. To connect the
extended Lorentz symmetry in the M(3,3) space with the physical space-time, a
fiber bundle over the 4D manifold is introduced with M(3,3) as a typical fiber.
The action is constructed which is invariant with respect to both general 4D
coordinate and local GL(4,M) spinor transformations. The components of the
metric on the 6D fiber are expressed in terms of the 4D pseudo-Riemannian
metric and two extra complex fields: 4D vector and scalar ones. These extra
fields describe in the general case massive particles interacting with an extra
U(1) gauge field and weakly interacting with ordinary particles, i.e.
possessing properties of invisible (dark) matter.Comment: 24 page
Keratin 8 variants are infrequent in patients with alcohol-related liver cirrhosis and do not associate with development of hepatocellular carcinoma
Application of mineralogical, petrological and geochemical tools for evaluating the palaeohdrogeological evolution of the PADAMOT study sites
The role of Work Package (WP) 2 of the PADAMOT project – ‘Palaeohydrogeological Data
Measurements’ - has been to study late-stage fracture mineral and water samples from
groundwater systems in Spain, Sweden, United Kingdom and the Czech Republic, with the aim
of understanding the recent palaeohydrogeological evolution of these groundwater systems. In
particular, the project sought to develop and evaluate methods for obtaining information about
past groundwater evolution during the Quaternary (about the last 2 million years) by examining
how the late-stage mineralization might record mineralogical, petrographical and geochemical
evidence of how the groundwater system may have responded to past geological and
climatological changes.
Fracture-flow groundwater systems at six European sites were studied:
• Melechov Hill, in the Bohemian Massif of the Czech Republic: a shallow (0-100 m)
dilute groundwater flow system within the near-surface weathering zone in fractured
granitic rocks;
• Cloud Hill, in the English Midlands: a (~100 m) shallow dilute groundwater flow system
in fractured and dolomitized Carboniferous limestone;
• Los Ratones, in southwest Spain: an intermediate depth (0-500 m) dilute groundwater
flow system in fractured granitic rocks;
• Laxemar, in southeast Sweden: a deep (0-1000 m) groundwater flow system in fractured
granitic rocks. This is a complex groundwater system with potential recharge and
flushing by glacial, marine, lacustrine and freshwater during the Quaternary;
• Sellafield, northwest England: a deep (0-2000 m) groundwater flow system in fractured
Ordovician low-grade metamorphosed volcaniclastic rocks and discontinuous
Carboniferous Limestone, overlain by a Permo-Triassic sedimentary sequence with
fracture and matrix porosity. This is a complex coastal groundwater system with deep
hypersaline sedimentary basinal brines, and deep saline groundwaters in crystalline
basement rocks, overlain by a shallow freshwater aquifer system. The site was glaciated
several times during the Quaternary and may have been affected by recharge from glacial
meltwater;
• Dounreay, northeast Scotland: a deep (0-1400 m) groundwater flow system in fractured
Precambrian crystalline basement overlain by fractured Devonian sedimentary rocks.
This is within the coastal discharge area of a complex groundwater system, comprising
deep saline groundwater hosted in crystalline basement, overlain by a fracture-controlled
freshwater sedimentary aquifer system. Like Sellafield, this area experienced glaciation
and may potentially record the impact of glacial meltwater recharge.
In addition, a study has been made of two Quaternary sedimentary sequences in Andalusia in
southeastern Spain to provide a basis of estimating the palaeoclimatic history of the region that
could be used in any reconstruction of the palaeoclimatic history at the Los Ratones site:
• The Cúllar-Baza lacustrine sequence records information about precipitation and
palaeotemperature regimes, derived largely from the analysis of the stable isotope (δ18O
and δ13C) signatures from biogenic calcite (ostracod shells).
• The Padul Peat Bog sequence provided information on past vegetation cover and
palaeogroundwater inputs based on the study of fossil pollen and biomarkers as proxies
for past climate change.
Following on from the earlier EC 4th Framework EQUIP project, the focus of the PADAMOT
studies has been on calcite mineralization. Calcite has been identified as a late stage mineral, closely associated with hydraulically-conductive fractures in the present-day groundwater
systems at the Äspö-Laxemar, Sellafield, Dounreay and Cloud Hill sites. At Los Ratones and
Melechov sites late-stage mineralization is either absent or extremely scarce, and both the
quantity and fine crystal size of any late-stage fracture mineralization relevant to Quaternary
palaeohydrogeological investigations is difficult to work with. The results from the material
investigated during the PADAMOT studies indicate that the fracture fillings at these sites are
related to hydrothermal activity, and so do not have direct relevance as Quaternary indicators.
Neoformed calcite has not been found at these two sites at the present depth of the investigations.
Furthermore, the HCO3
- concentration in all the Los Ratones groundwaters is mainly controlled
by complex carbonate dissolution. The carbonate mineral saturation indices do not indicate
precipitation conditions, and this is consistent with the fact that neoformed calcite, ankerite or
dolomite have not been observed petrographically
Potential medicinal value of some South African seaweeds
Eleven macroalgae were collected from the KwaZulu-Natal coast and nineteen species from the cooler Western Cape coast in March and April 2000. Ethanolic and aqueous extracts were made and tested for biological activity in the Cox-1 anti-inflammatory assay, in a nematode mortality bioassay for anthelminthic activity, an IC50 anticancer assay and a MIC antimicrobial assay. The ethanolic extracts were very active in the Cox-1 anti-inflammatory assay for almost all of the species tested. The aqueous extracts were not active. No anthelminthic mortality was detected in extracts from any of the species tested. Many of the extracts had cytotoxic activity against three cancer cell lines tested, with those from representative species of the Chlorophyta and Rhodophyta being the most effective. The extracts had much lower cytotoxic activity when tested on normal mouse fibroblasts (NIH3T3). Extracts from only a few species had antimicrobial activity with those of the Chlorophyta tested being the most effective against both the Gram-positive and Gram-negative bacteria
Non-Coding Keratin Variants Associate with Liver Fibrosis Progression in Patients with Hemochromatosis
Background: Keratins 8 and 18 (K8/K18) are intermediate filament proteins that protect the liver from various forms of injury. Exonic K8/K18 variants associate with adverse outcome in acute liver failure and with liver fibrosis progression in patients with chronic hepatitis C infection or primary biliary cirrhosis. Given the association of K8/K18 variants with endstage liver disease and progression in several chronic liver disorders, we studied the importance of keratin variants in patients with hemochromatosis. Methods: The entire K8/K18 exonic regions were analyzed in 162 hemochromatosis patients carrying homozygous C282Y HFE (hemochromatosis gene) mutations. 234 liver-healthy subjects were used as controls. Exonic regions were PCRamplified and analyzed using denaturing high-performance liquid chromatography and DNA sequencing. Previouslygenerated transgenic mice overexpressing K8 G62C were studied for their susceptibility to iron overload. Susceptibility to iron toxicity of primary hepatocytes that express K8 wild-type and G62C was also assessed. Results: We identified amino-acid-altering keratin heterozygous variants in 10 of 162 hemochromatosis patients (6.2%) and non-coding heterozygous variants in 6 additional patients (3.7%). Two novel K8 variants (Q169E/R275W) were found. K8 R341H was the most common amino-acid altering variant (4 patients), and exclusively associated with an intronic KRT8 IVS7+10delC deletion. Intronic, but not amino-acid-altering variants associated with the development of liver fibrosis. I
Evolución de los ácidos grasos en el mesocarpo del níspero (Mespilus germanica. L.) a diferentes estados de maduración
The fatty acid composition of medlar (Mespilus germanica L.) varied significantly among the ripening stages sampled at 157, 172 and 187 DAFs (days after full bloom). Twenty-one different fatty acids were detected in preclimacteric fruit and 17 when the climacteric began. Principal fatty acids, determined in medlar fruit harvested from October (157 and 172 DAFs) to November (187 DAF) were mainly palmitic acid (16:0), linoleic acid (18:2n-6), and a-linolenic acid (18:3n-3). While the content of saturated fatty acids [palmitic acid (16:0) and stearic acid (18:0)] increased, the content of the essential polyunsaturated fatty acids [linoleic acid (18:2n-6) and linolenic acid (18:3n-3)] decreased through ripening, in parallel with pulp darkening. The percentage of linoleic acid and a-linolenic acid in ripe, hard fruits was 60.0 and 13.5 % of dry wt at 157 DAF which decreased throughout ripening, remaining at 28.7 and 5.6 % of dry wt, respectively, in the fully softened and darkened pulp. A marked decreases in the double bond index, percentage of unsaturation and the ratio of unsaturation/saturation were also seen throughout the medlar ripening. The contribution of unsaturated fatty acid to the total fatty acid content decreased markedly as the medlar fruit became progressively softer and darkened.La composición en ácidos grasos del níspero (Mespilus germanica L.) varió significativamente entre los estados de maduración muestreados a los 157, 172 y 187 DAFs (días después de la floración). Veinte y un ácidos grasos diferentes fueron detectados en el fruto preclimatérico y 17 cuando comenzó el climaterio. Los ácidos grasos principales encontrados en nísperos, recolectados desde Octubre (157 y 172 DAFs) hasta Noviembre (187 DAF), fueron principalmente ácido palmítico (16:0), ácido linoléico (18:2n-6), y ácido a-linolénico (18:3n-3). En tanto que el contenido en ácidos grasos saturados (ácido palmítico (16:0) y ácido esteárico (18:0)) aumentó, el contenido en ácidos grasos esenciales (ácido linoleico (18:2n-6) y ácido linolénico (18:3n-6)) disminuyó durante la maduración, en paralelo con el oscurecimiento de la pulpa. El porcentaje de ácido linoleico y de ácido a-linolénico en frutos maduros sin reblandecer fue de 60.0 y 13.5 % del peso seco a 157 DAF, disminuyendo durante la maduración, y permaneciendo a 28.7 y 56 % del peso seco, respectivamente, en la pulpa completamente blanda y oscura. También se observó durante la maduración del níspero una marcada disminución en el número de dobles enlaces, en el tanto por ciento de instauración y en la relación instauración / saturación. La contribución de los ácidos grasos insaturados al contenido de ácidos grasos totales disminuyó marcadamente cuando el níspero comenzó progresivamente a reblandecerse y oscurecerse
Low Serum Hepcidin Is Associated With Reduced Shortâ Term Survival in Adults With Acute Liver Failure
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149282/1/hep30486_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149282/2/hep30486.pd
Evaluation of Implants, Clover, and Fescue Variety on Stocker Steers – Year 2
Sixty-four growing steers were used in a split-plot experiment, where the whole plot was pasture, and the split-plot was the implant level. Whole plot treatment was a 4 × 2 factorial with four levels of fescue (High Endophyte, Low Endophyte, Novel, or Endophyte Free) and two levels of legume (Legumes or No Legumes). The split-plot included four implant levels (No Implant, Synovex One Grass, Revalor-G, or Ralgro). Data collected were weights, hair coat scores, hair length, rectal temperature (every 28 days), and ultrasound carcass characteristics when steers were coming off grass. Steers on High Endophyte had the lowest average daily gain (ADG) and final weight and smallest loin muscle as compared to steers on all other fescue types. The gain differentiation was observed beginning at day 56 through the end of the study. Overall, ADG was not impacted by the addition of legume. Steers that were implanted with Synovex One Grass had a greater gain, final weight, and lower hair score as compared to non-implanted steers. For many of the other measures, steers implanted with Ralgro or Revalor-G resulted in changes between non-implanted steers and those receiving Synovex One Grass. Steers on high endophyte fescue had greater final weight and ADG than non-implanted steers or those receiving Ralgro, with Synovex One Grass being intermediate. Gains for steers on endophyte free pastures were also impacted by the type of implant where Synovex One Grass steers had greater gains than non-implanted and Revalor-G steers, with Ralgro being intermediate. In this second year of research, the use of low to no endophyte fescue and the addition of implants increased gains
Provisional Assessment of Candidate High-Temperature Thermal Conductivity Reference Materials in the EMRP “Thermo” Project
This article describes the provisional assessment of a short list of four candidate high-temperature thermal conductivity reference materials in a European research project, “Thermo.” These four candidate materials are low-density calcium silicate, amorphous silica, high-density calcium silicate, and exfoliated vermiculite. Based on initial tests on material composition and microstructure changes, dimensional stability, mechanical stability, chemical stability and uniformity, the best two candidate materials that would be considered for further detailed characterization in the next stage are low-density calcium silicate and high-density calcium silicate. These two materials are dimensionally, mechanically, and chemically stable, which are more robust and easier to handle than others. However, the specimens need to be selected to meet the requirement for material uniformity in terms of density, i.e., density variation within 2%
iP & OEIP - Cytokinin Micro Application Modulates Root Development with High Spatial Resolution
State-of-the-art technology based on organic electronics can be used as a flow-free delivery method for organic substances with high spatial resolution. Such highly targeted drug micro applications can be used in plant research for the regulation of physiological processes on tissue and cellular levels. Here, for the first time, an organic electronic ion pump (OEIP) is reported that can transport an isoprenoid-type cytokinin, N-6-isopentenyladenine (iP), to intact plants. Cytokinins (CKs) are plant hormones involved in many essential physiological processes, including primary root (PR) and lateral root (LR) development. Using the Arabidopsis thaliana root as a model system, efficient iP delivery is demonstrated with a biological output - cytokinin-related PR and LR growth inhibition. The spatial resolution of iP delivery, defined for the first time for an organic compound, is shown to be less than 1 mm, exclusively affecting the OEIP-targeted LR. Results from the application of the high-resolution OIEP treatment method confirm previously published findings showing that the influence of CKs may vary at different stages of LR development. Thus, OEIP-based technologies offer a novel, electronically controlled method for phytohormone delivery that could contribute to unraveling cytokinin functions during different developmental processes with high specificity
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