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Significant Pathway (significant + pathway)

Distribution by Scientific Domains

Medical Sciences	33%
Earth and Environmental Science	33%

Selected Abstracts

Quantification of Survival of Escherichia coli O157:H7 on Plants Affected by Contaminated Irrigation Water,

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2006
A. M. Ibekwe
Abstract Enterohemorrhagic E. coli O157: H7 (EHEC) is a major foodborne pathogen capable of causing diarrhea and vomiting, with further complications such as hemolytic-uremic syndrome (HUS). The aim of this study was to use the real-time PCR method to quantify the survival of Escherichia coli O157:H7/pGFP in phyllosphere (leaf surface), rhizosphere (volume of soil tightly held by plant roots), and non-rhizosphere soils (sand and clay) irrigated with contaminated water and compare the results obtained between real-time PCR method and conventional plate counts. The real-time PCR probe was designed to hybridize with the (eae) gene of E. coli O157:H7. The probe was incorporated into real-time PCR containing DNA extracted from the phyllosphere, rhizosphere, and non-rhizosphere soils irrigated with water artificially contaminated with E. coli O157:H7. The detection limit for E. coli O157:H7 quantification by real-time PCR was 2.3 × 103 in the rhizosphere and phyllosphere samples. E. coli O157:H7 survived longer in rhizosphere soil than the non-rhizosphere soil. The concentration of E. coli O157:H7/pGFP in rhizosphere soils was , 104 CFU/g in both soils at day 12 based on both plate count and real time PCR, with the clay soil significantly (P = 0.05) higher than the sandy soil. This data showed that E. coli O157H:7 can persist in the environment for more than 50 d, and this may pose some risk for both animal and human infection and provides a very significant pathway for pathogen recontamination in the environment. [source]

Bradykinin stimulates prostaglandin E2 production and cyclooxygenase activity in equine nonglandular and glandular gastric mucosa in vitro

EQUINE VETERINARY JOURNAL, Issue 4 2008
N. K. MORRISSEY
Summary Reasons for performing study: There are few data available regarding regulation of prostaglandin (PG) generation by equine gastric mucosae and the role of the cyclooxygenase (COX) isoforms in their production. Objectives: To: 1) characterise and quantify PGE2 output in vitro; 2) examine the sensitivity of PGE2 production to exogenous bradykinin (BK) exposure; 3) determine the contribution of the COX-1 and COX-2 pathways to basal and BK-stimulated PGE2 production; and 4) measure if BK influences electrogenic ion transport in equine gastric mucosae in vitro. Methods: Full thickness gastric sheets were obtained from horses at post mortem, stripped of muscle layers and mounted in Ussing chambers. Tissues were exposed to bradykinin (BK, 0.1 ,mol/l) either alone, or following pretreatment with a selective COX-2 inhibitor (NS-398, 1 ,mol/l) or a nonselective COX inhibitor (piroxicam, 1 ,mol/l), or were untreated. Results: BK administration increased PGE2 output from the basolateral but not the apical faces of both tissue types. Piroxicam, but not NS-398, reduced basolateral PGE2 release below control levels in both tissue types. Both piroxicam and NS-398 pretreatment inhibited BK-stimulated PGE2 release. In separate experiments, BK was without effect upon electrophysiological parameters of tissues mounted in Ussing chambers. Conclusions: PGE2 is produced by the nonglandular and glandular equine gastric mucosae in vitro. Significantly more PGE2 is released basolaterally than apically. BK stimulated the production of PGE2 from the basolateral side of both tissue types. These findings suggest that COX-1 is a significant pathway for basal PGE2 production from the basolateral faces of both nonglandular and glandular equine gastric mucosae in vitro. Potential relevance: The identification of the cells responsible for basolateral PGE2 release, via both COX-1 and COX-2 pathways, under basal and BK-stimulated conditions requires further study. [source]

Assessing the impacts and potential control of terrestrial plant colonization of a reservoir bed during an extreme drawdown event

LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 1 2009
A. Boulding
Abstract Extended periods of drawdown of reservoirs can result in the ,terrestrialization' of the lake bottom sediments, which describes the process whereby the exposed dry sediment takes on soil-like qualities. Opportunistic colonization of lake bed by terrestrial plants can occur under such conditions. A survey of plant communities of a large reservoir (Lake Hume) following its extreme drawdown, resulted in significant quantities of carbon, nitrogen and phosphorus being bound up in the terrestrial vegetation that colonized the lake bed. The phosphorus uptake from the sediment into plant material particularly could represent a significant pathway for phosphorus re-mobilization back into the lake. The potential of using stock grazing as a control measure for mitigating the effects of terrestrial plant colonization is also discussed. [source]

Addressing soil gas vapor intrusion using sustainable building solutions

REMEDIATION, Issue 4 2009
Ellen Moyer
Soil gas vapor intrusion (VI) emerged in the 1990s as one of the most important problems in the investigation and cleanup of thousands of sites across the United States. A common practice for sites where VI has been determined to be a significant pathway is to implement interim building engineering controls to mitigate exposure of building occupants to VI while the source of contamination in underlying soil and groundwater is assessed and remediated. Engineering controls may include passive barriers, passive or active venting, subslab depressurization, building pressurization, and sealing the building envelope. Another recent trend is the emphasis on "green" building practices, which coincidentally incorporate some of these same engineering controls, as well as other measures such as increased ventilation and building commissioning for energy conservation and indoor air quality. These green building practices can also be used as components of VI solutions. This article evaluates the sustainability of engineering controls in solving VI problems, both in terms of long-term effectiveness and "green" attributes. Long-term effectiveness is inferred from extensive experience using similar engineering controls to mitigate intrusion of radon, moisture, mold, and methane into structures. Studies are needed to confirm that engineering controls to prevent VI can have similar long-term effectiveness. This article demonstrates that using engineering controls to prevent VI is "green" in accelerating redevelopment of contaminated sites, improving indoor air quality, and minimizing material use, energy consumption, greenhouse gas emissions, and waste generation. It is anticipated that engineering controls can be used successfully as sustainable solutions to VI problems at some sites, such as those deemed technically impracticable to clean up, where remediation of underlying soil or groundwater contamination will not be completed in the foreseeable future. Furthermore, green buildings to be developed in areas of potential soil or groundwater contamination may be designed to incorporate engineering controls to prevent VI. © 2009 Wiley Periodicals, Inc. [source]

Pathways Among Exposure to Violence, Maternal Depression, Family Structure, and Child Outcomes Through Parenting: A Multigroup Analysis

AMERICAN JOURNAL OF ORTHOPSYCHIATRY, Issue 3 2010
T'Pring R. Westbrook
The present study examined the impact of proximal (maternal depression, family structure) and distal (exposure to violence) risk factors on parenting characteristics (warmth, control), which were in turn hypothesized to affect child social-emotional functioning. Using the Family and Child Experiences Study (FACES) 2000 cohort, findings revealed that study variables were significant predictors of child social-emotional functioning. Despite limited significant pathways in the structural equation models, the cumulative effect of the variables resulted in models accounting for 21%,37% of the outcome. Multigroup analysis revealed that although the amount of variance explained varied, the model held across subgroups. Findings support theories such as the family stress model that suggest that family risk factors negatively influencing children's development through influencing parenting behaviors. Findings also support considering both warmth and control as key parenting dimensions. It may be impractical for practitioners to address the myriad of potential risks encountered by low-income families, but parents can be equipped with mental health services, parent education, and other assistance to help them maintain positive parenting practices in the face of challenges. [source]

Mechanism of Laccase,TEMPO-Catalyzed Oxidation of Benzyl Alcohol

CHEMCATCHEM, Issue 7 2010
Sander
Abstract The oxidation of benzyl alcohol by air, catalyzed by the organocatalyst TEMPO and the enzyme laccase has been investigated. To establish the kinetically significant pathways and corresponding kinetic parameters, a series of experiments is conducted with synthesized stable oxidized and reduced forms of the organocatalyst, the oxoammonium cation, and hydroxylamine. The time course of TEMPO and its oxidized and reduced derivatives is monitored off line by a combination of GC analysis, UV/Vis spectroscopy, EPR spectroscopy, and FTIR spectroscopy. TEMPO is found to be regenerated through noncatalyzed comproportionation of the oxoammonium cation with hydroxylamine. A kinetic model is presented based on the experimentally determined kinetically significant pathways. The time dependences of the concentrations of the three redox states of TEMPO and benzyl alcohol are adequately described by the model. The results provide new leads for the development of a practical process for a combined laccase,TEMPO-catalyzed selective oxidation of alcohols. [source]