694 research outputs found
Prospects for terahertz imaging the human skin cancer with the help of gold-nanoparticles-based terahertz-to-infrared converter
The design is suggested, and possible operation parameters are discussed, of
an instrument to inspect a skin cancer tumour in the terahertz (THz) range,
transferring the image into the infrared (IR) and making it visible with the
help of standard IR camera. The central element of the device is the THz-to-IR
converter, a Teflon or silicon film matrix with embedded 8.5 nm diameter gold
nanoparticles. The use of external THz source for irradiating the biological
tissue sample is presumed. The converter's temporal characteristics enable its
performance in a real-time scale. The details of design suited for the
operation in transmission mode (in vitro) or on the human skin in reflection
mode {in vivo) are specified.Comment: To be published in the proceedings of the FANEM2018 workshop - Minsk,
3-5 June 201
A universal uptake mechanism for cobalt(II) on soil constituents: ferrihydrite, kaolinite, humic acid, and organo-mineral composites
Cobalt is a waste product in many industrial processes and its most common radioactive isotope – ⁶⁰Co – is a by-product of nuclear reactors. To better understand the mobility and fate of Co in natural and contaminated environments we investigated Co sorption behaviour to the common soil and sediment constituents ferrihydrite, kaolinite, humic acid (HA), and ferrihydrite-HA and kaolinite-HA organo-mineral composites using sorption batch experiments, synchrotron X-ray absorption spectroscopy (EXAFS), and scanning transmission electron microscopy (STEM). We measured the sorption of Co to the end-member mineral and organic phases and the composites as a function of pH, ionic strength and Co concentration, and also for the composites as a function of organic carbon concentration, with composites made containing a wide range of organic carbon contents. We then determined the molecular mechanisms of Co sorption to the end-member phases and the composites, and used this information to develop molecularly constrained thermodynamic surface complexation models to quantify Co sorption. Sorption to the ferrihydrite-HA and kaolinite-HA organo-mineral composites was found to be intermediate to both of the end-member phases, displaying enhanced sorption respective to the mineral end-member phase at mid-low pH. EXAFS analysis shows that there is a universal sorption mechanism accounting for Co sorption to the end-member mineral and organic phases and the organo-mineral composites at mid-high pH, in which Co sorbs to these phases via inner-sphere bidentate binuclear surface complexes. At mid-low pH, sorption to all the phases except ferrihydrite is the result of outer-sphere complexation. Our new molecularly constrained thermodynamic surface complexation models for Co sorption to ferrihydrite, kaolinite, HA, and ferrihydrite-HA and kaolinite-HA organo-mineral composites, show that Co sorption to the composites cannot be modelled assuming linear additivity of Co sorption to the end-member phases
Mechanochemical Synthesis, Characterization and Reactivity of a Room Temperature Stable Calcium Electride
\ua9 2024 The Authors. Published by American Chemical Society.A new calcium-based Room temperature Stable Electride (RoSE), K[{Ca[N(Mes)(SiMe3)]3(e-)}2K3] (2), is successfully synthesized from the reaction of a calcium tris-amide, [Ca{N(Mes)(SiMe3)}3K] (1) (Mes = 2,4,6-trimethylphenyl), with potassium under mechanochemical treatment. The dimeric structure of K[{Ca[N(Mes)(SiMe3)]3(e-)}2K3] is calculated using ab initio random structure searching (AIRSS) methods. This shows the existence of highly localized anionic electrons (e-) and suggests poor electrical conductance, as confirmed via electroconductivity measurements. The two anionic electrons in 2 are strongly antiferromagnetically coupled, thus in agreement with the largely diamagnetic response from magnetometry. Reaction of 2 with pyridine affords 4,4′-bipyridine, while reaction with benzene gives C-H activation and formation of a calcium hydride complex, [K(η6-C6H6)4][{Ca[N(Mes)(SiMe3)](H)}2K3] (3). Computational DFT analysis reveals the crucial role played by the ligand framework in the stabilization of this new Ca-hydride complex
Gravitational Waves from Gravitational Collapse
Gravitational wave emission from the gravitational collapse of massive stars
has been studied for more than three decades. Current state of the art
numerical investigations of collapse include those that use progenitors with
realistic angular momentum profiles, properly treat microphysics issues,
account for general relativity, and examine non--axisymmetric effects in three
dimensions. Such simulations predict that gravitational waves from various
phenomena associated with gravitational collapse could be detectable with
advanced ground--based and future space--based interferometric observatories.Comment: 68 pages including 13 figures; revised version accepted for
publication in Living Reviews in Relativity (http://www.livingreviews.org
Which circulating antioxidant vitamins are confounded by socioeconomic deprivation? The MIDSPAN family study
<p><b>Background:</b> Antioxidant vitamins are often described as having “independent” associations with risk of cancer, cardiovascular disease (CVD) and mortality. We aimed to compare to what extent a range of antioxidant vitamins and carotenoids are associated with adulthood and childhood markers of socioeconomic deprivation and to adverse lifestyle factors.</p>
<p><b>Methods and Findings:</b> Socioeconomic and lifestyle measures were available in 1040 men and 1298 women from the MIDSPAN Family Study (30–59 years at baseline) together with circulating levels of vitamins A, C, E, and carotenoids (α-carotene, β-carotene, lutein and lycopene). Markers of socioeconomic deprivation in adulthood were consistently as strongly associated with lower vitamin C and carotenoid levels as markers of adverse lifestyle; the inverse association with overcrowding was particularly consistent (vitamin C and carotenoids range from 19.1% [95% CI 30.3–6.0] to 38.8% [49.9–25.3] lower among those in overcrowded residencies). These associations were consistent after adjusting for month, classical CVD risk factors, body mass index, physical activity, vitamin supplements, dietary fat and fibre intake. Similar, but weaker, associations were seen for childhood markers of deprivation. The association of vitamin A or E were strikingly different; several adult adverse lifestyle factors associated with higher levels of vitamin A and E, including high alcohol intake for vitamin A (9.5% [5.7–13.5]) and waist hip ratio for vitamin E (9.5% [4.8–14.4]), with the latter associations partially explained by classical risk factors, particularly cholesterol levels.</p>
<p><b>Conclusions:</b> Plasma vitamin C and carotenoids have strong inverse associations with adulthood markers of social deprivation, whereas vitamin A and E appear positively related to specific adverse lifestyle factors. These findings should help researchers better contextualize blood antioxidant vitamin levels by illustrating the potential limitations associated with making causal inferences without consideration of social deprivation.</p>
Intraspecfic variation in cold-temperature metabolic phenotypes of Arabidopsis lyrata ssp petraea
Atmospheric temperature is a key factor in determining the distribution of a plant species. Alongside this, plant populations growing at the margin of their range may exhibit traits that indicate genetic differentiation and adaptation to their local abiotic environment. We investigated whether geographically separated marginal populations of Arabidopsis lyrata ssp. petraea have distinct metabolic phenotypes associated with exposure to cold temperatures. Seeds of A. petraea were obtained from populations along a latitudinal gradient, namely Wales, Sweden and Iceland and grown in a controlled cabinet environment. Mannose, glucose, fructose, sucrose and raffinose concentrations were different between cold treatments and populations, especially in the Welsh population, but polyhydric alcohol concentrations were not. The free amino acid compositions were population specific, with fold differences in most amino acids, especially in the Icelandic populations, with gross changes in amino acids, particularly those associated with glutamine metabolism. Metabolic fingerprints and profiles were obtained. Principal component analysis (PCA) of metabolite fingerprints revealed metabolic characteristic phenotypes for each population and temperature. It is suggested that amino acids and carbohydrates were responsible for discriminating populations within the PCA. Metabolite fingerprinting and profiling has proved to be sufficiently sensitive to identify metabolic differences between plant populations at different atmospheric temperatures. These findings show that there is significant natural variation in cold metabolism among populations of A. l. petraea which may signify plant adaptation to local climates
Collapse of a giant iceberg in a dynamic Southern Ocean marine ecosystem: In situ observations of A-68A at South Georgia
Large icebergs (>20 km long) are responsible for most of the freshwater discharged into the Southern Ocean. We report on in situ and satellite observations made during the break-up phase around South Georgia of the giant tabular iceberg A-68A. The in situ measurements were obtained during a 4-day visit by a research vessel in February 2021, where physical, chemical and biological measurements were made at a range of distances away
from the main and subsidiary icebergs. These results were compared to a far-field station 133 km away. Up�stream of the iceberg field, water column structure was similar to ambient water although there was evidence of iceberg-associated phytoplankton as a likely remnant of the passage of the icebergs. Nevertheless, enhancement of primary productivity along the path of the icebergs was not resolved in either in situ or monthly mean satellite observations. There was a considerable brash-ice field moving ahead of the icebergs which limited the number of downstream sampling stations. One downstream station within 2 km of iceberg A-68P showed several ice-melt influenced features that distinguished it from most other stations. Firstly, there was a strong stratified meltwater influenced layer that reached to around 120 m. This had the effect of deepening underlying water masses, with
the core of the temperature minimum layer around 50 m deeper than elsewhere. Secondly, there was evidence of rapid downward displacement of both particulate material and certain phytoplankton taxa that may be a further result of this water mass deepening. Thirdly, macronutrient profiles were altered, with concentrations of nitrate, silicic acid and phosphate characteristic of deeper layers being found closer to the surface and a dilution of the ambient nutrient pool just above the iceberg draft that we ascribe to meltwater released from basal melting. Meanwhile, nutrient recycling processes associated with organic matter remineralisation were also modified by the physical restructuring of the water column and biotic components. Finally, the ice-associated phytoplankton
taxa Pseudo-nitszchia/Nitszchia, found in both upstream and downstream locations, were abundant at this < 2 km-distant station through melting out from the iceberg and subsequent rapid growth. Overall, we resolved alterations to water column structure, nutrient profiles and phytoplankton community composition at fine to medium scales around the iceberg field. Nevertheless, although there may have been longer term and larger scale impacts, the dynamic oceanographic environment, including the presence of a strong oceanographic front and
shelf-edge processes, dominated during the collapse of A-68A
Pathogenic variants in MT-ATP6: A UK-based Mitochondrial Disease Cohort Study
Distinct clinical syndromes have been associated with pathogenic MT-ATP6 variants. In this cohort study, we identified 125 individuals (60 families) including 88 clinically affected individuals and 37 asymptomatic carriers. Thirty-one individuals presented with Leigh syndrome and seven with Neuropathy Ataxia Retinitis Pigmentosa. The remaining 50 patients presented with variable non-syndromic features including ataxia, neuropathy and learning disability. We confirmed maternal inheritance in 39 families, and demonstrated tissue segregation patterns and phenotypic threshold are variant-dependent. Our findings suggest that MT-ATP6-related mitochondrial disease is best conceptualised as a spectrum disorder and should be routinely included in genetic ataxia and neuropathy gene panels. This article is protected by copyright. All rights reserved
Dietary Supplementation with Probiotics Improves Hematopoiesis in Malnourished Mice
BACKGROUND: Lactobacillus rhamnosus CRL1505 (Lr) administered during the repletion of immunocompromised-malnourished mice improves the resistance against intestinal and respiratory infections. This effect is associated with an increase in the number and functionality of immune cells, indicating that Lr could have some influence on myeloid and lymphoid cell production and maturation. OBJECTIVE: This study analyzed the extent of the damage caused by malnutrition on myeloid and lymphoid cell development in the spleen and bone marrow (BM). We also evaluated the impact of immunobiotics on the recovery of hematopoiesis affected in malnourished mice. METHODS: Protein malnourished mice were fed on a balanced conventional diet for 7 or 14 consecutive d with or without supplemental Lr or fermented goat's milk (FGM). Malnourished mice and well-nourished mice were used as controls. Histological and flow cytometry studies were carried out in BM and spleen to study myeloid and lymphoid cells. RESULTS: Malnutrition induced quantitative alterations in spleen B and T cells; however, no alteration was observed in the ability of splenic B cells to produce immunoglobulins after challenge with LPS or CpG. The analysis of BM B cell subsets based on B220, CD24, IgM and IgD expression showed that malnutrition affected B cell development. In addition, BM myeloid cells decreased in malnourished mice. On the contrary, protein deprivation increased BM T cell number. These alterations were reverted with Lr or FGM repletion treatments since normal numbers of BM myeloid, T and B cells were observed in these groups. CONCLUSIONS: Protein malnutrition significantly alters B cell development in BM. The treatment of malnourished mice with L. rhamnosus CRL1505 was able to induce a recovery of B cells that would explain its ability to increase immunity against infections. This work highlights the possibility of using immunobiotics to accelerate the recovery of lymphopoyesis in immunocompromised-malnourished hosts
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