986 resultados para Foam cell
Resumo:
Atmospheric-pressure plasma (APP) has been successfully used to treat several types of cancers in vivo and in vitro, with the effect being primarily attributed to the generation of reactive oxygen species (ROS). However, the mechanisms by which APP induces apoptosis in cancer cells require further elucidation. In this study, the effects of APP on the expression of 500 genes in melanoma Mel007 cancer cells were examined. Pro-apoptotic phorbol-12-myristate-13-acetate-induced protein (PMAIP1), also known as NOXA, was highly expressed as a result of APP treatment in a dose-dependent manner. Blocking of ROS using scavenger NAC or silencing of NOXA gene by RNA interference inhibited the APP-induced NOXA genes upregulation and impaired caspases 3/7 mediated apoptosis, confirming the important role plasma-generated ROS species and pro-apoptotic NOXA play in APP-induced cancer cell death.
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A novel type of magnesium-air primary cell has been evolved which employs non-polluting and abundantly available materials. The cell is based on the scheme Mg/Mg(NO3)2, NaNO2, H20/Q(C). The magnesium anode utilization is about 90% at a current density of 20 mAcm -2. The anode has been shown to exhibit a low open-circuit corrosion, a relatively uniform pattern of corrosion and a low negative difference effect in the electrolyte developed above as compared to the conventional halide or perchlorate electrolytes. In the usual air-depolarized mode of operation, the cell has been found to be capable of continuous discharge over several months at a constant cell voltage of about 1 V and a current density of 1 mAcm -2 at the cathode. The long service-life capability arises from the formation of a protective film on the porous carbon cathode and fast sedimentation of the anodic product (magnesium hydroxide) in the electrolyte. The cell has a shelf-life in the activated state of about a year due to the low open-circuit corrosion of the anode. These favourable features suggest the practical feasibility of developing economical, long-life, non-reserve magnesium-air ceils for diverse applications using magnesium anodes with a high surface area and porous carbon-air electrodes.
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The oxidation of sodium sulphide in the presence of fine activated carbon particles (4.33 μm) has been studied at 75°C in a foam bed contactor. The existing single-stage model of a foam bed reactor has been modified to take into account the effect of heterogeneous catalyst particles and the absorption in the storage section. The variables studied are catalyst loading, initial sulphide concentration and the average liquid hold-up in the foam bed. It is seen that the rates of oxidation of sodium sulphide are considerably enhanced by an increase in the loading of activated carbon particles. The rate of conversion of sodium sulphide also increases with an increase in the average liquid hold-up in the foam. The modified model predicts these effects fairly well. The contribution of reaction in the storage section is found to be less than 2% of the overall rate of conversion in the contactor.
Resumo:
Separately, polyphenols and plant cell walls (PCW) are important contributors to the health benefits associated with fruits and vegetables. However, interactions with PCW which occur either during food preparation or mastication may affect bioaccessibility and hence bioavailability of polyphenols. Binding interactions between anthocyanins, phenolic acids (PAs) and PCW components, were evaluated using both a bacterial cellulose-pectin model system and a black carrot puree system. The majority of available polyphenols bound to PCW material with 60-70% of available anthocyanins and PAs respectively binding to black carrot puree PCW matter. Once bound, release of polyphenols using acidified methanol is low with only similar to 20% of total anthocyanins to similar to 30% of PAs being released. Less than 2% of bound polyphenol was released after in vitro gastric and small intestinal (S.I.) digestion for both the model system and the black carrot puree PCW matter. Confocal laser scanning microscopy shows localised binding of anthocyanins to PCW. Very similar patterns of binding for anthocyanins and PAs suggest that PAs form complexes with anthocyanins and polysaccharides. Time dependent changes in extractability with acidified methanol but not the total bound fraction suggests that initial nonspecific deposition on cellulose surfaces is followed by rearrangement of the bound molecules. Minimal release of anthocyanins and PAs after simulated gastric and S.I. digestion indicates that polyphenols in fruits and vegetables which bind to the PCW will be transported to the colon where they would be expected to be released by the action of cell wall degrading bacteria.
Resumo:
Bacterial cellulose and cellulose-pectin composites were used as well-defined model plant cell wall (PCW) systems to study the interaction between phenolic acids (PA) derived from purple carrot juice concentrate (PCJC) and PCW components. Significant PA depletion from solution occurred, with pure cellulose initially (30 s-1 h) absorbing more than cellulose-pectin composites in the first hour (ca 20% cf 10-15%), but with all composites absorbing similar levels (ca 30%) after several days. Individual PAs bound to different relative extents with caffeic acid > chlorogenic acid > ferulic acid. Extrapolation of data for these model systems to carrot puree suggests that nutritionally-significant amounts of PAs could bind to cell walls, potentially restricting bioavailability in the small intestine and, as a consequence, delivering PAs to the large intestine for fermentation and metabolism by gut bacteria. (C) 2012 Elsevier Ltd. All rights reserved.
Resumo:
The crush bands that form during plastic deformation of closed-cell metal foams are often inclined at 11-20 degrees to the loading axis, allowing for shear displacement of one part of the foam with respect to the other. Such displacement is prevented by the presence of a lateral constraint. This was analysed in this study, which shows that resistance against shear by the constraint leads to the strain-hardening effect in the foam that has been reported in a recent experimental study. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Resumo:
The incidence of colon cancer is high in Western societies, and in Finland it is among the three most common cancer types in both females and males. Environmental factors, including diet, affect colon cancer development. During the last few years, a vast amount of new, functional foods have been introduced to the consumers. Several products are already available that are marketed as promoting intestinal health. To be able to reliably call a dietary compound a chemopreventive substance it is of fundamental importance to understand the mechanism by which it affects tumour formation and the integrity of the epithelial cells. In this thesis, three different dietary compounds were studied in an experimental model of colon cancer. Inulin is a non-digestible fibre found naturally in chicory roots, artichokes and onions, amongst others. Nowadays it is widely used as an added dietary fibre in several food products. Conjugated linoleic acid (CLA) is a conjugated form of the fatty acid linoleic acid. CLA is formed by bacterial fermentation of linoleic acid in the rumen of cows and other ruminants. Concomitantly, it can naturally be found in milk and meat of ruminants. White currant is a colourless berry low in phenolic compounds that are believed to prevent cancer formation. Contrary to what was expected, inulin and the conjugated linoleic acid isomer trans-10, cis-12, were tumour growth promoting dietary constituents when fed to Min mice. Both diets decreased the NF-kappaB levels in the mucosa, but physiological adenoma development did not affect NF-kappaB. Diet altered beta-catenin and p53 signalling in the adenomas, confirming their involvement in adenoma growth. White currant, on the other hand, was chemopreventive, despite its low contents of phenolic compounds. The chemopreventive effect was accompanied by increased p53 levels in the mucosa, and decreased beta-catenin and NF-kappaB levels in the adenoma. This could explain the reduced adenoma number and size. The results underline the importance of carefully testing new dietary compounds in different settings to reliably confirm their health benefits. In this study two compounds that are consumed and believed to add to our health proved to be cancer promotive. A berry with low phenolic contents, on the other hand, was chemopreventive.
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Exposure to aqueous film forming foam (AFFF) was evaluated in 149 firefighters working at AFFF training facilities in Australia by analysis of PFOS and related compounds in serum. A questionnaire was designed to capture information about basic demographic factors, lifestyle factors and potential occupational exposure (such as work history and self-reported skin contact with foam). The results showed that a number of factors were associated with PFAA serum concentrations. Blood donation was found to be linked to low PFAA levels, and the concentrations of PFOS and PFHxS were found to be positively associated with years of jobs with AFFF contact. The highest levels of PFOS and PFHxS were one order of magnitude higher compared to the general population in Australia and Canada. Study participants who had worked ten years or less had levels of PFOS that were similar to or only slightly above those of the general population. This coincides with the phase out of 3M AFFF from all training facilities in 2003, and suggests that the exposures to PFOS and PFHxS in AFFF have declined in recent years. Self-reporting of skin contact and frequency of contact were used as an index of exposure. Using this index, there was no relationship between PFOS levels and skin exposure. This index of exposure is limited as it relies on self-report and it only considers skin exposure to AFFF, and does not capture other routes of potential exposure. Possible associations between serum PFAA concentrations and five biochemical outcomes were assessed. The outcomes were serum cholesterol, triglycerides, high-density lipoproteins, low density lipoproteins, and uric acid. No statistical associations between any of these endpoints and serum PFAA concentrations were observed.
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This research project investigated a bioreactor system capable of high density cell growth intended for use in regenerative medicine and protein production. The bioreactor was based on a drip-perfusion concept and constructed with minimal costs, readily available components, and straightforward processes for usage. This study involved the design, construction, and testing of the bioreactor where the results showed promising three dimensional cell growth within a polymer structure. The accessibility of this equipment and the capability of high density, three dimensional cell growth would be suitable for future research in pharmaceutical drug manufacturing, and human organ and tissue regeneration.
Resumo:
Bovine Viral Diarrhoea Virus (BVDV) is widely distributed in cattle industries and causes significant economic losses worldwide annually. A limiting factor in the development of subunit vaccines for BVDV is the need to elicit both antibody and T-cell-mediated immunity as well as addressing the toxicity of adjuvants. In this study, we have prepared novel silica vesicles (SV) as the new generation antigen carriers and adjuvants. With small particle size of 50 nm, thin wall (similar to 6 nm), large cavity (similar to 40 nm) and large entrance size (5.9 nm for SV-100 and 16 nm for SV-140), the SV showed high loading capacity (similar to 250 mu g/mg) and controlled release of codon-optimised E2 (oE2) protein, a major immunogenic determinant of BVDV. The in vivo functionality of the system was validated in mice immunisation trials comparing oE2 plus Quil A (50 mu g of oE2 plus 10 mu g of Quil A, a conventional adjuvant) to the oE2/SV-140 (50 mu g of oE2 adsorbed to 250 mu g of SV-140) or oE2/SV-140 together with 10 mu g of Quil A. Compared to the oE2 plus Quil A, which generated BVDV specific antibody responses at a titre of 10(4), the oE2/SV-140 group induced a 10 times higher antibody response. In addition, the cell-mediated response, which is essential to recognise and eliminate the invading pathogens, was also found to be higher [1954-2628 spot forming units (SFU)/million cells] in mice immunised with oE2/SV-140 in comparison to oE2 plus Quil A (512-1369 SFU/million cells). Our study has demonstrated that SV can be used as the next-generation nanocarriers and adjuvants for enhanced veterinary vaccine delivery. (C) 2014 Elsevier Ltd. All rights reserved.
Resumo:
The present study examined whether a specific property of cell microstructures may be useful as a biomarker of aging. Specifically, the association between age and changes of cellular structures reflected in electrophoretic mobility of cell nuclei index (EMN index) values across the adult lifespan was examined. This report considers findings from cross sections of females (n = 1273) aged 18–98 years, and males (n = 506) aged 19–93 years. A Biotest apparatus was used to perform intracellular microelectrophoresis on buccal epithelial cells collected from each individual. EMN index was calculated on the basis of the number of epithelial cells with mobile nuclei in reference to the cells with immobile nuclei per 100 cells. Regression analyses indicated a significant negative association between EMN index value and age for men (r = −0.71, p < 0.001) and women (r = −0.60, p < 0.001); demonstrating a key requirement that must be met by a biomarker of aging. The strength of association observed between EMN index and age for both men and women was encouraging and supports the potential use of EMN index for determining a biological age of an individual (or a group). In this study, a new attempt of complex explanation of cellular mechanisms contributing to age related changes of the EMN index was made. In this study, a new attempt of complex explanation of cellular mechanisms contributing to age related changes of the EMN index was made. EMN index has demonstrated potential to meet criteria proposed for biomarkers of aging and further investigations are necessary.
Resumo:
The antifungal drug, miconazole nitrate, inhibits the growth of several species of Candida. Candida albicans, one of the pathogenic species, was totally inhibited at a concentration of approximately 10 μg/ml. Endogenous respiration was unaffected by the drug at a concentration as high as 100 μg/ml, whereas exogenous respiration was markedly sensitive and inhibited to an extent of 85%. The permeability of the cell membrane was changed as evidenced by the leakage of 260-nm absorbing materials, amino acids, proteins, and inorganic cations. The results we present clearly show that the drug alters the cellular permeability, and thus the exogenous respiration becomes sensitive to the drug.
Resumo:
Location management problem that arise in mobile computing networks is addressed. One method used in location management is to designate sonic of the cells in the network as "reporting cells". The other cells in the network are "non-reporting cells". Finding an optimal set of reporting cells (or reporting cell configuration) for a given network. is a difficult combinatorial optimization problem. In fact this is shown to be an NP-complete problem. in an earlier study. In this paper, we use the selective paging strategy and use an ant colony optimization method to obtain the best/optimal set of reporting cells for a given a network.
Resumo:
On the basis of dodecahedral structure of a foam bed, a model to predict conversion in a foam bed contactor with mass transfer with chemical reaction has been developed. To verify the proposed model, experiments have been carried out in a semi-batch apparatus for the absorption of lean CO2 gas in a foam of sodium hydroxide solution. The proposed model predicts fairly well the experimentally found absorption values.
Resumo:
Healthy transparent cornea depends upon the regulation of fluid, nutrient and oxygen transport through the tissue to sustain cell metabolism and other critical processes for normal functioning. This research considers the corneal geometry and investigates oxygen distribution using a two-dimensional Monod kinetic model, showing that previous studies make assumptions that lead to predictions of near-anoxic levels of oxygen tension in the limbal regions of the cornea. It also considers the comparison of experimental spatial and temporal data with the predictions of novel mathematical models with respect to distributed mitotic rates during corneal epithelial wound healing.