936 resultados para Libraries affected by Hurricane Irene
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E-cadherin is a major cell-cell adhesion protein of epithelia that is trafficked to the basolateral cell surface in a polarized fashion. The exact post-Golgi route and regulation of E-cadherin transport have not been fully described. The Rho GTPases Cdc42 and Rac1 have been implicated in many cell functions, including the exocytic trafficking of other proteins in polarized epithelial cells. These Rho family proteins are also associated with the cadherin-catenin complexes at the cell surface. We have used functional mutants of Rac1 and Cdc42 and inactivating toxins to demonstrate specific roles for both Cdc42 and Rac1 in the post-Golgi transport of E-cadherin. Dominant-negative mutants of Cdc42 and Rac1 accumulate E-cadherin at a distinct post-Golgi step. This accumulation occurs before p120(ctn) interacts with E-cadherin, because p120(ctn) localization was not affected by the Cdc42 or Rac1 mutants. Moreover, the GTPase mutants had no effect on the trafficking of a targeting mutant of E-cadherin, consistent with the selective involvement of Cdc42 and Rac1 in basolateral trafficking. These results provide a new example of Rho GTPase regulation of basolateral trafficking and demonstrate novel roles for Cdc42 and Rac1 in the post-Golgi transport of E-cadherin.
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Background. Older adults typically exhibit dramatic reductions in the rate of force development and deficits in the execution of rapid coordinated movements. The purpose of the current study was to investigate the association between the reduced rate of force development exhibited by older adults and the ability to coordinate groups of muscles. Methods. The performance of a visually guided aiming task that required the generation of isometric torque about the elbow joint was compared in 10 young adults (age range, 19 to 29 years) and 10 older adults (age range, 65 to 80 years). Participants were required to exert isometric torque in flexion, extension, pronation, or supination, or in combinations of these directions, to reach a target in minimum time. Surface electromyograms were obtained from the biceps brachii, triceps brachii, brachioradialis, and flexor carpi radialis. Results. Older participants exhibited slower target acquisition times compared with young participants (p < .05), with the extent of the differences between the groups varying markedly between target locations. Conclusions. The impairment in performance, although partially attributable to a general decline in the ability to produce force rapidly, was also affected by the requirements for muscular coordination. At the neuromuscular level, differences between the young and the elderly were expressed most prominently in the bifunctional muscle biceps brachii and in certain temporal aspects of muscular coordination.
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Enhanced biological phosphorus removal (EBPR) performance is directly affected by the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs). This study investigates the effects of carbon source on PAO and GAO metabolism. Enriched PAO and GAO cultures were tested with the two most commonly found volatile fatty acids (VFAs) in wastewater systems, acetate and propionate. Four sequencing batch reactors (SBRs) were operated under similar conditions and influent compositions with either acetate or propionate as the sole carbon source. The stimulus for selection of the PAO and GAO phenotypes was provided only through variation of the phosphorus concentration in the feed. The abundance of PAOs and GAOs was quantified using fluorescence in situ hybridisation (FISH). In the acetate fed PAO and GAO reactors, Candidatus Accumulibacter phosphatis (a known PAO) and Candidatus Competibacter phosphatis (a known GAO) were present in abundance. A novel GAO, likely belonging to the group of Alphaproteobacteria, was found to dominate the propionate fed GAO reactor. The results clearly show that there are some very distinctive differences between PAOs and GAOs in their ability to take up acetate and propionate. PAOs enriched with acetate as the sole carbon source were immediately able to take up propionate, likely at a similar rate as acetate. However, an enrichment of GAOs with acetate as the sole carbon source took up propionate at a much slower rate (only about 5% of the rate of acetate uptake on a COD basis) during a short-term switch in carbon source. A GAO enrichment with propionate as the sole carbon source took up acetate at a rate that was less than half of the propionate uptake rate on a COD basis. These results, along with literature reports showing that PAOs fed with propionate (also dominated by Accumulibacter) can immediately switch to acetate, suggesting that PAOs are more adaptable to changes in carbon source as compared to GAOs. This study suggests that the PAO and GAO competition could be influenced in favour of PAOs through the provision of propionate in the feed or even by regularly switching the dominant VFA species in the wastewater. Further study is necessary in order to provide greater support for these hypotheses. (c) 2005 Wiley Periodicals, Inc.
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In this experiment, creatinine (C) excretion by sheep was measured when they were fed different diets at different levels of intake. Creatinine excretion was not affected by the level of feed intake or the addition of salt to lucerne-based diets. However, differences between individual animals were significant. Creatinine excretion was significantly affected by diets, which were formulated by combining different amounts of lucerne chaff, oaten chaff and sorghum. It was also found that there were significant diurnal changes in the ratios of purine derivatives to creatinine (PD:C) in 3 hourly urine samples when the animals were fed either once or twice daily, but the average value for the PD:C ratio of any two urine samples taken 12 h apart was close to the daily mean. The results of this experiment suggest that if separate determination of the creatinine excretion by individual animals is made and the average value of the ratio of PD:C in two spot urine samples taken 12 h apart is used to predict PD excretion by spot urine sampling, microbial nitrogen flow can be estimated more accurately than when a fixed value of creatinine excretion is used for all animals and only a single urine sample is taken. (c) 2005 Elsevier B.V. All rights reserved.
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The cause of seasonal failure of a nitrifying municipal landfill leachate treatment plant utilizing a fixed biofilm was investigated by wastewater analyses and batch respirometric tests at every treatment stage. Nitrification of the leachate treatment plant was severely affected by the seasonal temperature variation. High free ammonia (NH3-N) inhibited not only nitrite oxidizing bacteria (NOB) but also ammonia oxidizing bacteria (AOB). In addition, high pH also increased free ammonia concentration to inhibit nitrifying activity especially when the NH4-N level was high. The effects of temperature and free ammonia of landfill leachate on nitrification and nitrite accumulation were investigated with a semi-pilot scale biofilm airlift reactor. Nitrification rate of landfill leachate increased with temperature when free ammonia in the reactor was below the inhibition level for nitrifiers. Leachate was completely nitrified up to a load of 1.5 kg NH4-N m(-3) d(-1) at 28 degrees C. The activity of NOB was inhibited by NH3-N resulting in accumulation of nitrite. NOB activity decreased more than 50% at 0.7 mg NH3-N L-1. Fluorescence in situ hybridization (FISH) was carried out to analyze the population of AOB and NOB in the nitrite accumulating nitrifying biofilm. NOB were located close to AOB by forming small clusters. A significant fraction of AOB identified by probe Nso1225 specifically also hybridized with the Nitrosonlonas specific probe Nsm156. The main NOB were Nitrobacter and Nitrospira which were present in almost equal amounts in the biofilm as identified by simultaneous hybridization with Nitrobacter specific probe Nit3 and Nitrospira specific probe Ntspa662. (c) 2005 Elsevier Ltd. All rights reserved.
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1. Some of the most damaging invasive plants are dispersed by frugivores and this is an area of emerging importance in weed management. It highlights the need for practical information on how frugivores affect weed population dynamics and spread, how frugivore populations are affected by weeds and what management recommendations are available. 2. Fruit traits influence frugivore choice. Fruit size, the presence of an inedible peel, defensive chemistry, crop size and phenology may all be useful traits for consideration in screening and eradication programmes. By considering the effect of these traits on the probability, quality and quantity of seed dispersal, it may be possible to rank invasive species by their desirability to frugivores. Fruit traits can also be manipulated with biocontrol agents. 3. Functional groups of frugivores can be assembled according to broad species groupings, and further refined according to size, gape size, pre- and post-ingestion processing techniques and movement patterns, to predict dispersal and establishment patterns for plant introductions. 4. Landscape fragmentation can increase frugivore dispersal of invasives, as many invasive plants and dispersers readily use disturbed matrix environments and fragment edges. Dispersal to particular landscape features, such as perches and edges, can be manipulated to function as seed sinks if control measures are concentrated in these areas. 5.Where invasive plants comprise part of the diet of native frugivores, there may be a conservation conflict between control of the invasive and maintaining populations of the native frugivore, especially where other threats such as habitat destruction have reduced populations of native fruit species. 6. Synthesis and applications. Development of functional groups of frugivore-dispersed invasive plants and dispersers will enable us to develop predictions for novel dispersal interactions at both population and community scales. Increasingly sophisticated mechanistic seed dispersal models combined with spatially explicit simulations show much promise for providing weed managers with the information they need to develop strategies for surveying, eradicating and managing plant invasions. Possible conservation conflicts mean that understanding the nature of the invasive plant-frugivore interaction is essential for determining appropriate management.
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Transient prenatal vitamin D deficiency produces hyperlocomotion in the adult rat. The aim of this study was to examine the effects of acute restraint on the behaviour of DVD and control rats in the open field. Rats were conceived and born to developmentally vitamin D (DVD) deficient or replete (control) dams and, at 8 weeks of age, were monitored for 30 min in an open field using automated video tracking software. Half of the rats were restrained within a towel for 5 min immediately before the open field test. The remainder received minimal handling prior to the open field test. Repeating previous findings, DVD deficient animals had enhanced locomotion during the first 10 min of the open field test compared to control rats. By contrast, there were no differences in locomotor activity after acute restraint stress. The time rats spent in the corners and side of the open field was affected by prenatal diet. DVD rats spent less time in the corners and more time in the side than control rats across the whole 30 min test. This difference was not seen in rats with acute restraint stress. The time spent in the centre was not altered by prenatal diet or acute restraint. Thus, transient prenatal vitamin D deficiency induces a transient spontaneous hyperlocomotion in adulthood that is modulated by acute restraint stress. (c) 2006 Elsevier B.V. All rights reserved.
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Adiponectin is a secreted, multimeric protein with insulin-sensitizing, antiatherogenic, and antiinflammatory properties. Serum adiponectin consists of trimer, hexamer, and larger high-molecular-weight (HMW) multimers, and these HMW multimers appear to be the more bioactive forms. Multimer composition of adiponectin appears to be regulated; however, the molecular mechanisms involved are unknown. We hypothesize that regulation of adiponectin multimerization and secretion occurs via changes in posttranslational modifications (PTMs). Although a structural role for intertrimer disulfide bonds in the formation of hexamers and HMW multimers is established, the role of other PTMs is unknown. PTMs identified in murine and bovine adiponectin include hydroxylation of multiple conserved proline and lysine residues and glycosylation of hydroxylysines. By mass spectrometry, we confirmed the presence of these PTMs in human adiponectin and identified three additional hydroxylations on Pro71, Pro76, and Pro95. We also investigated the role of the five modified lysines in multimer formation and secretion of recombinant human adiponectin expressed in mammalian cell lines. Mutation of modified lysines in the collagenous domain prevented formation of HMW multimers, whereas a pharmacological inhibitor of prolyl- and lysyl-hydroxylases, 2,2'-dipyridyl, inhibited formation of hexamers and HMW multimers. Bacterially expressed human adiponectin displayed a complete lack of differentially modified isoforms and failed to form bona fide trimers and larger multimers. Finally, glucose-induced increases in HMW multimer production from human adipose explants correlated with changes in the two-dimensional electrophoresis profile of adiponectin isoforms. Collectively, these data suggest that adiponectin multimer composition is affected by changes in PTM in response to physiological factors.
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Mesoporous chromium oxide (Cr2O3) nanocrystals were first synthesized by the thermal decomposition reaction of Cr(NO3)(3)(circle)9H(2)O using citric acid monohydrate (CA) as the mesoporous template agent. The texture and chemistry of chromium oxide nanocrystals were characterized by N-2 adsorption-desorption isotherms, FTIR, X-ray diffraction (XRD), UV-vis, and thermoanalytical methods. It was shown that the hydrate water and CA are the crucial factors in influencing the formation of mesoporous Cr2O3 nanocrystals in the mixture system. The decomposition of CA results in the formation of a mesoporous structure with wormlike pores. The hydrate water of the mixture provides surface hydroxyls that act as binders, making the nanocrystals aggregate. The pore structures and phases of chromium oxide are affected by the ratio of precursor-to-CA, thermal temperature, and time.
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The present study gives a contribution to the knowledge on the Na-feldspar and plagioclases, extending the database of the Raman spectra of plagioclases with different chemical compositions and structural orders. This information may be used for the future planetary explorations by “rovers”, for the investigation of ceramics nanocrystal materials and for the mineralogical phase identification in sediments. Na-feldspar and plagioclase solid solution have been investigated by Raman spectroscopy in order to determine the relationships between the vibrational changes and the plagioclase crystal chemistry and structure. We focused on the Raman micro-spectroscopy technique, being a non-destructive method, suited for contactless analysis with high spatial resolution. Chemical and structural analyses have been performed on natural samples to test the usefulness of Raman spectroscopy as a tool in the study of the pressure-induced structural deformations, the disordering processes due to change in the Al-Si distribution in the tetrahedral sites and, finally, in the determination of the anorthitic content (Anx) in plagioclase minerals. All the predicted 39 Ag Raman active modes have been identified and assigned to specific patterns of atomic vibrational motion. A detailed comparison between experimental and computed Raman spectra has been performed and previous assignments have been revised, solving some discrepancies reported in recent literature. The ab initio calculation at the hybrid HF/DFT level with the WC1LYP Hamiltonian has proven to give excellent agreement between calculated and experimentally measured Raman wavenumbers and intensities in triclinic minerals. A short digression on the 36 infrared active modes of Na-feldspar has been done too. The identification of all 39 computed Raman modes in the experimentally measured spectra of the fully ordered Na-feldspar, known as low albite, along with the detailed description of each vibrational mode, has been essential to extend the comparative analysis to the high pressure and high temperature structural forms of albite, which reflect the physical–chemical conditions of the hosting rocks. The understanding of feldspar structure response to pressure and temperature is crucial in order to constrain crustal behaviour. The compressional behaviour of the Na-feldspar has been investigated for the first time by Raman spectroscopy. The absence of phase transitions and the occurrence of two secondary compression mechanisms acting at different pressures have been confirmed. Moreover, Raman data suggest that the internal structural changes are confined to a small pressure interval, localized around 6 GPa, not spread out from 4 to 8 GPa as suggested by previous X-rays studies on elasticity. The dominant compression mechanisms act via tetrahedral tilting, while the T-O bond lengths remain nearly constant at moderate compressional regimes. At the spectroscopic level, this leads to the strong pressure dependencies of T-O-T bending modes, as found for the four modes at 478, 508, 578 and 815 cm-1. The Al-Si distribution in the tetrahedral sites affects also the Raman spectrum of Na-feldspar. In particular, peak broadening is more sensitive than peak position to changes in the degree of order. Raman spectroscopy is found to be a good probe for local ordering, in particular being sensitive to the first annealing steps, when the macroscopic order parameter is still high. Even though Raman data are scattered and there are outliers in the estimated values of the degree of order, the average peak linewidths of the Na-feldspar characteristic doublet band, labelled here as υa and υb, as a function of the order parameter Qod show interesting trends: both peak linewidths linearly increase until saturation. From Qod values lower than 0.6, peak broadening is no more affected by the Al-Si distribution. Moreover, the disordering process is found to be heterogeneous. SC-XRD and Raman data have suggested an inter-crystalline inhomogeneity of the samples, i.e., the presence of regions with different defect density on the micrometric scale. Finally, the influence of Ca-Na substitution in the plagioclase Raman spectra has been investigated. Raman spectra have been collected on a series of well characterized natural, low structural plagioclases. The variations of the Raman modes as a function of the chemical composition and the structural order have been determined. The number of the observed Raman bands at each composition gives information about the unit-cell symmetry: moving away from the C1 structures, the number of the Raman bands enhances, as the number of formula units in the unit cell increases. The modification from an “albite-like” Raman spectrum to a more “anorthite-like” spectrum occurs from sample An78 onwards, which coincides with the appearance of c reflections in the diffraction patterns of the samples. The evolution of the Raman bands υa and υb displays two changes in slope at ~An45 and ~An75: the first one occurs between e2 and e1 plagioclases, the latter separates e1 and I1 plagioclases with only b reflections in their diffraction patterns from I1 and P1 samples having b and c reflections too. The first variation represents exactly the e2→e1 phase transitions, whereas the second one corresponds in good approximation to the C1→I1 transition, which has been determined at ~An70 by previous works. The I1→P1 phase transition in the anorthite-rich side of the solid solution is not highlighted in the collected Raman spectra. Variations in peak broadening provide insights into the behaviour of the order parameter on a local scale, suggesting an increase in the structural disorder within the solid solution, as the structures have to incorporate more Al atoms to balance the change from monovalent to divalent cations. All the information acquired on these natural plagioclases has been used to produce a protocol able to give a preliminary estimation of the chemical composition of an unknown plagioclase from its Raman spectrum. Two calibration curves, one for albite-rich plagioclases and the other one for the anorthite-rich plagioclases, have been proposed by relating the peak linewidth of the most intense Raman band υa and the An content. It has been pointed out that the dependence of the composition from the linewidth can be obtained only for low structural plagioclases with a degree of order not far away from the references. The proposed tool has been tested on three mineralogical samples, two of meteoric origin and one of volcanic origin. Chemical compositions by Raman spectroscopy compare well, within an error of about 10%, with those obtained by elemental techniques. Further analyses on plagioclases with unknown composition will be necessary to validate the suggested method and introduce it as routine tool for the determination of the chemical composition from Raman data in planetary missions.
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Cardiovascular disease (CVD) is the leading cause of death in Europe responsible for more than 4.3 million deaths annually. The World Health Organisation funded the Monica project (1980s-1990s) which monitored ten million subjects aged 22-6Syrs, and demonstrated that coronary heart disease (CHD) mortality declined over 10 years, was due in two thirds of cases to reduced incidence of CHD (reduced risk behaviours e.g. poor diet and smoking) and one third by improved treatments. Epidemiological evidence suggests diets rich in antioxidants decrease incidence of CVD. Regular consumption of nuts, rich in vitamin E and polyphenols reduces atherosclerosis, an important risk for heart disease. Intervention studies to date using alpha tocopherol (an active component of vitamin E) have not consistently proved beneficial. This thesis aims to investigate the effect of almond supplementation on vascular risk factors in healthy young males (18-3Syrs); mature males and female(>SOyrs); and males considered at increased risk of CVD (18-3Syrs) in a cohort of 67 subjects. The effects of almond intake were assessed after 2Sg/d for four weeks followed by SOg/d for four weeks and compared to a control group which did not consume almonds or change their diet. Cardiovascular risk was assessed by plasma lipid profiles, apolipoprotein A1, plasma nitrates/nitrates, vascular flow, BMl, blood pressure, sVCAM-1 and protein oxidation. Systolic and diastolic blood pressures were reduced in almond supplemented volunteers but not in controls. Dietary monounsaturated fatty acids, polyunsaturated fatty acid content and total dietary fats were increased by almond supplementation. Neither sVCAM-1, venous occlusion plethysmography nor plasma nitrite levels were affected by almond intake in any independent group. No significant changes in plasma lipids, and apolipoprotein A1 were observed. In conclusion almonds supplementation caused a reduction in blood pressure that may be due to increased sensitivity of the baroreceptors after increased monounsaturated fatty acid intake.
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Mineralogical investigations have determined the sites of u and Th associated with two radioelement-enriched granites from different geological settings. In the Ririwai ring complex, Nigeria, the u- and Th-bearing accessories have been greatly affected by post-magmatic alteration of the biotite granite. Primary thorite, zircon and monazite were altered to Zr(±Y)-rich thorite, partially metamict zircon (enriched in Th, U, Y, P, Fe, Mn, Ca) and an unidentified LREE-phase respectively, by pervasive fluids which later precipitated Zr-rich coffinite. More intense, localised alteration and albitisation completely remobilised primary accessories and gave rise to a distinctive generation of haematite- and uranothorite-enriched zircon with clear, Hi-enriched rims and xenotime overgrowths. In the Ririwai lode, microclinisation and later greisenisation locally remobilised or altered zircon and deposited Y-ricl1 coffinite and Y(±Zr)-rich thorite which was overgrown by traces of xenotime and LREE-phase(s) of complex and variable composition. Compositions indicating extensive solid-solution among thorite, coffinite, xenotime and altered zircon are probably metastable and formed at low temperatures. The widespread occurrence of REE-rich fluorite suggests that F-complexing aided the mobility of REE, Y, U, Th and Zr during late-magmatic to post-magmatic alteration, while uranyl-carbonate complexing may have occurred during albitisation. The Caledonian, Helmsdale granite in northern Scotland has undergone pervasive and localised hydrothermal alteration associated with U enrichment. Zircon xenocrysts, primary sphene and apatite contain a small.proportion of this U which is largely adsorbed on to secondary iron-oxide, TiOand phyllosilicates.Additional sites for U in the overlying, Lower Devonian Ousdale arkose include coffinite, secondary uranyl phosphates, hydrocarbon and traces of xenotime and unidentified LREE-phases. U may have been leached from the granite and deposited in the arkose, along channelways associated with the Helmsdale fault, by convecting, hydrothermal fluids
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The drug efflux pump P-glycoprotein (P-gp) (ABCB1) confers multidrug resistance, a major cause of failure in the chemotherapy of tumours, exacerbated by a shortage of potent and selective inhibitors. A high throughput assay using purified P-gp to screen and characterise potential inhibitors would greatly accelerate their development. However, long-term stability of purified reconstituted ABCB1 can only be reliably achieved with storage at -80 °C. For example, at 20 °C, the activity of ABCB1 was abrogated with a half-life of <1 day. The aim of this investigation was to stabilise purified, reconstituted ABCB1 to enable storage at higher temperatures and thereby enable design of a high throughput assay system. The ABCB1 purification procedure was optimised to allow successful freeze drying by substitution of glycerol with the disaccharides trehalose or maltose. Addition of disaccharides resulted in ATPase activity being retained immediately following lyophilisation with no significant difference between the two disaccharides. However, during storage trehalose preserved ATPase activity for several months regardless of the temperature (e.g. 60% retention at 150 days), whereas ATPase activity in maltose purified P-gp was affected by both storage time and temperature. The data provide an effective mechanism for the production of resilient purified, reconstituted ABCB1.
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Periodontitis, a ubiquitous chronic inflammatory disease, is associated with reduced antioxidant defences and neutrophil hyperactivity in terms of reactive oxygen species (ROS) generation. Its phenotype is thus characterized by oxidative stress. We have determined the effect of antioxidant micronutrients ascorbate and α-tocopherol on neutrophil ROS generation. Peripheral neutrophils from periodontally-healthy individuals (n = 20) were challenged with phorbol myristate acetate, IgG-opsonised Staphylococcus aureus, Fusobacterium nucleatum or PBS in the presence and absence of micronutrients (50 μM). Total and extracellular ROS were measured by luminol and isoluminol chemiluminescence respectively. Total and extracellular unstimulated, baseline ROS generation was unaffected by α-tocopherol, but inhibited by ascorbate and a combination of both micronutrients. Fcγ-receptor (Fcγ-R)-stimulated total or extracellular ROS generation was not affected by the presence of individual micronutrients. However, the combination significantly reduced extracellular FcγR-stimulated ROS release. Neither micronutrient inhibited TLR-stimulated total ROS, but the combination caused inhibition. Ascorbate and the micronutrient combination, but not α-tocopherol, inhibited extracellular ROS release by TLR-stimulated cells. Such micronutrient effects in vivo could be beneficial in reducing collateral tissue damage in chronic inflammatory diseases, such as periodontitis, while retaining immune-mediated neutrophil function. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
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This study proposes a new type of greenhouse for water re-use and energy saving for agriculture in arid and semi-arid inland regions affected by groundwater salinity. It combines desalination using reverse osmosis (RO), re-use of saline concentrate rejected by RO for cooling, and rainwater harvesting. Experimental work was carried at GBPUAT, Pantnagar, India. Saline concentrate was fed to evaporative cooling pads of greenhouse and found to evaporate at similar rates as conventional freshwater. Two enhancements to the system are described: i) A jet pump, designed and tested to use pressurized reject stream to re-circulate cooling water and thus maintain uniform wetness in cooling pads, was found capable of multiplying flow of cooling water by a factor of 2.5 to 4 while lifting water to a head of 1.55 m; and ii) Use of solar power to drive ventilation fans of greenhouse, for which an electronic circuit has been produced that uses maximum power-point tracking to maximize energy efficiency. Re-use of RO rejected concentrate for cooling saves water (6 l d-1 m-2) of greenhouse floor area and the improved fan could reduce electricity consumption by a factor 8.