567 research outputs found
The identification and significance of inputs to Anthrosols in North-West Europe
In recent years there has been a renewed interest in soils which are the result of past land management practices involving substantial additions of mineral and organic matter. However, there is still a substantial lack of detailed information on their formation. Anthrosols are distinguished by the presence of a deep top horizon and such soils were investigated at sites in Scotland, Denmark and The Netherlands. Field data and samples were collected from eight sites under arable cultivation, meadowland and woodland. Particle size distribution, pH, loss on ignition, ECEC, base saturation and total P were measured. Carbonaceous particles were identified through micromorphological analysis and the determination of O:C ratios using an electron microprobe. Despite the use of different inputs in recent centuries and different current land management, the resultant anthropogenic soils are remarkably similar in field and analytical properties. Nevertheless, subtle changes in particle size can be explained by parent material influences, material imported by farmers and by inputs by other processes such as by wind. The results from microprobe analysis demonstrate the importance of carbonaceous particles in storing phosphorus. Thus the inherent fertility of these Anthrosols can be explained in part by the application of carbonised material in the past
Historic landscape management: a validation of quantitative soil thin-section analyses
The archaeological interpretation of past land management practices can be greatly enhanced through examination of soil thin sections. Features relating to manuring practice are among those key to interpreting agricultural practices. The sources and the pro¬cesses leading to the distribution of these manure materials may further improve knowledge of the past landscape utilisation. The use of quantitative analyses to examine soil thin sections opens the possibility of considering these relationships between manured areas in greater detail and to extract more subtle spatial and temporal changes in past management. In this study the validation of this methodology has been tested with quantitative image analysis methods used to examine manure inputs to a well-documented historical landscape of Papa Stour, Shetland, where intensive manuring has been practised until the 1960s. By using both historic and ethnographic evidence to validate the image analysis protocol, differences in spatial and temporal distribution are examined for the practices of manuring with both fuel residues and with turf. The validation of the hypotheses expected from ethnographic and historical data that quantitative soils-based evidence allows the definition of variations in manuring strategies and provides a more secure basis from which to interpret manuring management strategies in archaeological landscapes
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Characterization of carbon monoxide, methane and nonmethane hydrocarbons in emerging cities of Saudi Arabia and Pakistan and in Singapore
We investigate the composition of 63 C2-C10 nonmethane hydrocarbons (NMHCs), methane (CH4) and carbon monoxide (CO), in Jeddah, Mecca, and Madina (Saudi Arabia), in Lahore, (Pakistan), and in Singapore. We established a database with which to compare and contrast NMHCs in regions where ambient levels and emissions are poorly characterized, but where conditions are favorable to the formation of tropospheric ozone, and where measurements are essential for improving emission inventories and modeling. This dataset will also serve as a base for further analysis of air pollution in Western Saudi Arabia including, but not limited to, the estimation of urban emissions and long range pollution transport from these regions. The measured species showed enhanced levels in all Saudi Arabian cities compared to the local background but were generally much lower than in Lahore. In Madina, vehicle exhaust was the dominant NMHC source, as indicated by enhanced levels of combustion products and by the good correlation between NMHCs and CO, while in Jeddah and Mecca a combination of sources needs to be considered. Very high NMHC levels were measured in Lahore, and elevated levels of CH4 in Lahore were attributed to natural gas. When we compared our results with 2010 emissions from the MACCity global inventory, we found discrepancies in the relative contribution of NMHCs between the measurements and the inventory. In all cities, alkenes (especially ethene and propene) dominated the hydroxyl radical (OH) reactivity (kOH) because of their great abundance and their relatively fast reaction rates with OH
Regional Differences Between Perisynovial and Infrapatellar Adipose Tissue Depots and Their Response to Class II and III Obesity in Patients with OA
Proline dehydrogenase is essential for proline protection against hydrogen peroxide induced cell death
Proline metabolism has an underlying role in apoptotic signaling that impacts tumorigenesis. Proline is oxidized to glutamate in the mitochondria with the rate limiting step catalyzed by proline dehydrogenase (PRODH). PRODH expression is inducible by p53 leading to increased proline oxidation, reactive oxygen species (ROS) formation, and induction of apoptosis. Paradoxical to its role in apoptosis, proline also protects cells against oxidative stress. Here we explore the mechanism of proline protection against hydrogen peroxide stress in melanoma WM35 cells. Treatment of WM35 cells with proline significantly increased cell viability, diminished oxidative damage of cellular lipids and proteins, and retained ATP and NADPH levels after exposure to hydrogen peroxide. Inhibition or siRNA-mediated knockdown of PRODH abolished proline protection against oxidative stress whereas knockdown of Δ1-pyrroline-5- carboxylate reductase, a key enzyme in proline biosynthesis, had no impact on proline protection. Potential linkages between proline metabolism and signaling pathways were explored. The combined inhibition of the mammalian target of rapamycin complex 1 (mTORC1) and mTORC2 eliminated proline protection. A significant increase in Akt activation was observed in proline treated cells after hydrogen peroxide stress along with a corresponding increase in the phosphorylation of the fork head transcription factor class O3a (FoxO3a). The role of PRODH in proline mediated protection was validated in the prostate carcinoma cell line, PC3. Knockdown of PRODH in PC3 cells attenuated phosphorylated levels of Akt and FoxO3a and decreased cell survival during hydrogen peroxide stress. The results provide evidence that PRODH is essential in proline protection against hydrogen peroxide mediated cell death and that proline/PRODH helps activate Akt in cancer cells
Proline dehydrogenase is essential for proline protection against hydrogen peroxide induced cell death
Proline metabolism has an underlying role in apoptotic signaling that impacts tumorigenesis. Proline is oxidized to glutamate in the mitochondria with the rate limiting step catalyzed by proline dehydrogenase (PRODH). PRODH expression is inducible by p53 leading to increased proline oxidation, reactive oxygen species (ROS) formation, and induction of apoptosis. Paradoxical to its role in apoptosis, proline also protects cells against oxidative stress. Here we explore the mechanism of proline protection against hydrogen peroxide stress in melanoma WM35 cells. Treatment of WM35 cells with proline significantly increased cell viability, diminished oxidative damage of cellular lipids and proteins, and retained ATP and NADPH levels after exposure to hydrogen peroxide. Inhibition or siRNA-mediated knockdown of PRODH abolished proline protection against oxidative stress whereas knockdown of Δ1-pyrroline-5- carboxylate reductase, a key enzyme in proline biosynthesis, had no impact on proline protection. Potential linkages between proline metabolism and signaling pathways were explored. The combined inhibition of the mammalian target of rapamycin complex 1 (mTORC1) and mTORC2 eliminated proline protection. A significant increase in Akt activation was observed in proline treated cells after hydrogen peroxide stress along with a corresponding increase in the phosphorylation of the fork head transcription factor class O3a (FoxO3a). The role of PRODH in proline mediated protection was validated in the prostate carcinoma cell line, PC3. Knockdown of PRODH in PC3 cells attenuated phosphorylated levels of Akt and FoxO3a and decreased cell survival during hydrogen peroxide stress. The results provide evidence that PRODH is essential in proline protection against hydrogen peroxide mediated cell death and that proline/PRODH helps activate Akt in cancer cells
Holography and Eternal Inflation
We show that eternal inflation is compatible with holography. In particular,
we emphasize that if a region is asymptotically de Sitter in the future,
holographic arguments by themselves place no bound on the number of past
e-foldings. We also comment briefly on holographic restrictions on the
production of baby universes.Comment: 14 pages, 3 figures, revtex4, (v2 relation with work of Banks and
Fischler clarified, references added
Survey of whole air data from the second airborne Biomass Burning and Lightning Experiment using principal component analysis
Hydrocarbon and halocarbon measurements collected during the second airborne Biomass Burning and Lightning Experiment (BIBLE-B) were subjected to a principal component analysis (PCA), to test the capability for identifying intercorrelated compounds within a large whole air data set. The BIBLE expeditions have sought to quantify and understand the products of burning, electrical discharge, and general atmospheric chemical processes during flights arrayed along the western edge of the Pacific. Principal component analysis was found to offer a compact method for identifying the major modes of composition encountered in the regional whole air data set. Transecting the continental monsoon, urban and industrial tracers (e.g., combustion byproducts, chlorinated methanes and ethanes, xylenes, and longer chain alkanes) dominated the observed variability. Pentane enhancements reflected vehicular emissions. In general, ethyl and propyl nitrate groupings indicated oxidation under nitrogen oxide (NOx) rich conditions and hence city or lightning influences. Over the tropical ocean, methyl nitrate grouped with brominated compounds and sometimes with dimethyl sulfide and methyl iodide. Biomass burning signatures were observed during flights over the Australian continent. Strong indications of wetland anaerobics (methane) or liquefied petroleum gas leakage (propane) were conspicuous by their absence. When all flights were considered together, sources attributable to human activity emerged as the most important. We suggest that factor reductions in general and PCA in particular may soon play a vital role in the analysis of regional whole air data sets, as a complement to more familiar methods
Differential response to bacteria, and TOLLIP expression, in the human respiratory tract.
OBJECTIVES: The observation that pathogenic bacteria are commonly tolerated in the human nose, yet drive florid inflammation in the lung, is poorly understood, partly due to limited availability of primary human cells from each location. We compared responses to bacterial virulence factors in primary human nasal and alveolar cells, and characterised the distribution of Toll-interacting protein (TOLLIP; an inhibitor of Toll-like receptor (TLR) signalling) in the human respiratory tract. METHODS: Primary cells were isolated from nasal brushings and lung tissue taken from patients undergoing pulmonary resection. Cells were exposed to lipopolysaccharide, lipoteichoic acid, peptidoglycan, CpG-C DNA or tumour necrosis factor (TNF). Cytokines were measured in cell supernatants. TOLLIP was characterised using quantitative real-time PCR and immunofluorescence. RESULTS: In primary alveolar, but not primary nasal, cells peptidoglycan significantly increased secretion of interleukin (IL)-1β, IL-6, IL-8, IL-10 and TNF. TLR2 expression was significantly higher in alveolar cells and correlated with IL-8 production. TOLLIP expression was significantly greater in nasal cells. CONCLUSION: In conclusion, primary human alveolar epithelial cells are significantly more responsive to peptidoglycan than primary nasal epithelial cells. This may partly be explained by differential TLR2 expression. TOLLIP is expressed widely in the human respiratory tract, and may contribute to the regulation of inflammatory responses
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