972 resultados para And leaf water potential
Bacteria in the cold deep-sea benthic boundary layer and sediment-water interface of the NE Atlantic
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The objective of this study was to determine how structure, stratigraphy, and weathering influence fate and transport of contaminants (particularly U) in the ground water and geologic material at the Department of Energy (DOE) Environmental Remediation Sciences Department (ERSD) Field Research Center (FRC). Several cores were collected near four former unlined adjoining waste disposal ponds. The cores were collected, described, analyzed for U, and compared with ground water geochemistry from surrounding multilevel wells. At some locations, acidic U-contaminated ground water was found to preferentially flow in small remnant fractures weathering the surrounding shale (nitric acid extractable U [UNA] usually <50 mg kg–1) into thin (
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The paper deals with use of a food grade coagulant (guar gum) as a replacement for synthetic coagulants for potable water treatment.
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The O removal through water formation is an important process in the Fischer-Tropsch synthesis. In this study, both steps in water formation (O + H --> OH, OH + H --> H2O) are studied on the stepped Co(0001) at high coverages using density functional theory. We find the following. (i) In both O-O and O-OH co-adsorption systems, two transition states (TSs) were located for the O hydrogenation: in one TS, both O and H are on the same terrace, and in the other they are at the interface between the step edge and the terrace below. (ii) In both the O-O and O-OH co-adsorption systems, the O hydrogenation at the interface is easier (E-a = 0.32 eV in the O-O system, E-a = 1.10 eV in the O-OH system) than that on the same terrace (E-a = 1.49 eV in the O-O system, E-a = 1.80 eV in the O-OH system). (iii) In both the O-O and O-OH co-adsorption systems, only one TS for the OH hydrogenation was located, in which both OH and H are on the same terrace. (iv) Compared to the OH hydrogenation in the O-OH system (E-a = 1.46 eV), the reaction in the OH-OH system (E-a = 0.64 eV) is much easier. The barrier differences and the water effect on the Fischer-Tropsch synthesis are discussed. A possible route with low barriers for water formation is proposed.
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Acetaminophen [N-acetyl-p-aminophenol (APAP)] is the most common antipyretic/analgesic medicine worldwide. If APAP is overdosed, its metabolite, N-acetyl-p-benzo-quinoneimine (NAPQI), causes liver damage. However, epidemiological evidence has associated previous use of therapeutic APAP doses with the risk of chronic obstructive pulmonary disease (COPD) and asthma. The transient receptor potential ankyrin-1 (TRPA1) channel is expressed by peptidergic primary sensory neurons. Because NAPQI, like other TRPA1 activators, is an electrophilic molecule, we hypothesized that APAP, via NAPQI, stimulates TRPA1, thus causing airway neurogenic inflammation. NAPQI selectively excites human recombinant and native (neuroblastoma cells) TRPA1. TRPA1 activation by NAPQI releases proinflammatory neuropeptides (substance P and calcitonin gene-related peptide) from sensory nerve terminals in rodent airways, thereby causing neurogenic edema and neutrophilia. Single or repeated administration of therapeutic (15-60 mg/kg) APAP doses to mice produces detectable levels of NAPQI in the lung, and increases neutrophil numbers, myeloperoxidase activity, and cytokine and chemokine levels in the airways or skin. Inflammatory responses evoked by NAPQI and APAP are abated by TRPA1 antagonism or are absent in TRPA1-deficient mice. This novel pathway, distinguished from the tissue-damaging effect of NAPQI, may contribute to the risk of COPD and asthma associated with therapeutic APAP use.-Nassini, R., Materazzi, S., Andre, E., Sartiani, L., Aldini, G., Trevisani, M., Carnini, C., Massi, D., Pedretti, P., Carini, M., Cerbai, E., Preti, D., Villetti, G., Civelli, M., Trevisan, G., Azzari, C., Stokesberry, S., Sadofsky, L., McGarvey, L., Patacchini, R., Geppetti, P. Acetaminophen, via its reactive metabolite N-acetyl-p-benzo-quinoneimine and transient receptor potential ankyrin-1 stimulation causes neurogenic inflammation in the airways and other tissues in rodents. FASEB J. 24, 4904-4916 (2010). www.fasebj.org
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A stationary phase model is used to study supercritical waves generated by high speed ferries. Some general relationships in terms of wave angle, propagation direction, dispersion relationship and depth wavelength relationship are explored and discussed. In particular, it is shown that the wave pattern generated by high speed craft at supercritical speeds depends mainly on the relationship of water depth and ship speed and that the wave patterns are similar in terms of location of crests and troughs for a given depth Froude number. In addition it is found that the far field wave pattern can be described adequately using a single moving point source. The theoretical model compares well with towing tank measurements and full scale data over a range of parameters and hull shapes. The paper also demonstrates that the far field wave pattern at supercritical speeds should be non-dimensionalised by water depth and not hull length unlike it is usually done for subcritical speeds.