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Institution

University of Guelph

EducationGuelph, Ontario, Canada
About: University of Guelph is a education organization based out in Guelph, Ontario, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 26542 authors who have published 50553 publications receiving 1715255 citations. The organization is also known as: U of G & Guelph University.


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Journal ArticleDOI
19 Jul 2001-Nature
TL;DR: Modelling indicates that the thermolysis of fluoropolymers in industrial and consumer high-temperature applications is likely to be a significant source of trifluoroacetate in urban rain water, and CFCs and fluorocarbons—groups that can destroy ozone and act as greenhouse gases, respectively—are detected among the other thermal degradation products, suggesting that continued use of fluor polymers may also exacerbate stratospheric ozone-depletion and global warming.
Abstract: Following the introduction of hydrochlorofluorocarbon (HCFCs) and hydrofluorocarbon (HFCs) gases as replacements for the ozone-destroying chlorofluorocarbons (CFCs), it has been discovered that HCFCs/HFCs can degrade in the atmosphere to produce trifluoroacetic acid1, a compound with no known loss mechanisms in the environment2,3, and higher concentrations in natural waters4 have been shown to be mildly phytotoxic5. Present environmental levels of trifluooracetic acid are not accounted by HCFC/HFC degradation alone8,9,10. Here we report that thermolysis of fluorinated polymers, such as the commercial polymers Teflon and Kel-F, can also produce trifluoroacetate and the similar compound chlorodifluoroacetate. This can occur either directly, or indirectly via products that are known to degrade to these haloacetates in the atmosphere11. The environmental significance of these findings is confirmed by modelling, which indicates that the thermolysis of fluoropolymers in industrial and consumer high-temperature applications (ovens, non-stick cooking utensils and combustion engines) is likely to be a significant source of trifluoroacetate in urban rain water (∼25 ng l-1, as estimated for Toronto). Thermolysis also leads to longer chain polyfluoro- and/or polychlorofluoro- (C3–C14) carboxylic acids which may be equally persistent. Some of these products have recently been linked with possible adverse health6 and environmental impacts and are being phased out of the US market7. Furthermore, we detected CFCs and fluorocarbons—groups that can destroy ozone and act as greenhouse gases, respectively—among the other thermal degradation products, suggesting that continued use of fluoropolymers may also exacerbate stratospheric ozone-depletion and global warming.

267 citations

Journal Article
TL;DR: It is proposed that 1,25-dihydroxyvitamin D3 blocks these autoimmune symptoms by stimulating the differentiation and/or function of cells that inhibit the encephalitogenic process by increasing IL-4 transcripts by 3- to 25-fold and TGF-beta 1 transcripts by 4- to 24-fold.
Abstract: Previously we demonstrated that 1,25-dihydroxyvitamin D3 blocks the progression of relapsing encephalomyelitis. We now propose that 1,25-dihydroxyvitamin D3 blocks these autoimmune symptoms by stimulating the differentiation and/or function of cells that inhibit the encephalitogenic process. To support this belief, we have found that 1,25-dihydroxyvitamin D3 administration to mice increases IL-4 transcripts by 3- to 25-fold and TGF-beta 1 transcripts by 4- to 24-fold. Similarly, IL-4 and TGF-beta 1 transcripts were higher in the central nervous system of 1,25-dihydroxyvitamin D3-treated mice compared with controls. The number of cells recoverable from the lymph nodes of 1,25-dihydroxyvitamin D3-treated mice was only 50% that of controls. Overall, 1,25-dihydroxyvitamin D3 treatment causes a net loss in the total number of lymphocytes while the number of IL-4 and TGF-beta 1 transcripts increased. The systemic and local increase in the expression of these two anti-inflammatory cytokines by 1,25-dihydroxyvitamin D3 may be responsible for the ability of this drug to block encephalomyelitis.

266 citations

Journal ArticleDOI
TL;DR: It appears that the current North American freshwater fish taxonomy at the species level significantly conceals diversity in some groups, although artificially creating diversity in others, according to a survey of named species.
Abstract: Freshwater ecosystems are being heavily exploited and degraded by human activities all over the world, including in North America, where fishes and fisheries are strongly affected. Despite centuries of taxonomic inquiry, problems inherent to species identification continue to hamper the conservation of North American freshwater fishes. Indeed, nearly 10% of species diversity is thought to remain undescribed. To provide an independent calibration of taxonomic uncertainty and to establish a more accessible molecular identification key for its application, we generated a standard reference library of mtDNA sequences (DNA barcodes) derived from expert-identified museum specimens for 752 North American freshwater fish species. This study demonstrates that 90% of known species can be delineated using barcodes. Moreover, it reveals numerous genetic discontinuities indicative of independently evolving lineages within described species, which points to the presence of morphologically cryptic diversity. From the 752 species analyzed, our survey flagged 138 named species that represent as many as 347 candidate species, which suggests a 28% increase in species diversity. In contrast, several species of parasitic and nonparasitic lampreys lack such discontinuity and may represent alternative life history strategies within single species. Therefore, it appears that the current North American freshwater fish taxonomy at the species level significantly conceals diversity in some groups, although artificially creating diversity in others. In addition to providing an easily accessible digital identification system, this study identifies 151 fish species for which taxonomic revision is required.

266 citations

Journal ArticleDOI
TL;DR: In this article, the synergistic integration of low carbon to nitrogen ratio (C/N) biomass with high C/N ratio lignocellulosic biomass in an anaerobic digestion (AD) system appears to be a logical option to enhance biogas yield.
Abstract: Global annual production of lignocellulosic biomass including undervalued agricultural residues and greenhouse biomass is about 181.5 billion tonnes. This undervalued biomass has a high potential to produce biogas in anaerobic digestion (AD). Among the various pre-treatment methods, hydrothermal (HT) pre-treatment of lignocellulosic biomass is a promising approach to increase biogas production in AD. However, the high carbon to nitrogen ratio (C/N) of lignocellulosic biomass is reported to be the major limiting factor for a higher biogas yield. Hence, the synergistic integration of low C/N ratio biomass with high C/N ratio lignocellulosic biomass in an AD system appears to be a logical option to enhance biogas yield. High moisture lignocellulosic biomass HT pretreatment and biogas production in AD have the potential for renewable energy production with limited use of process energy. However, hydrothermal process temperature, AD substrate C/N ratio and its inhibitory elements are important parameters for optimum biogas production. Greenhouse biomass pretreatment in hydrothermal process can produce biochar, biogas and biofertilizer, which can be used as input heat and nutrient source for greenhouses. Finally, the operation of greenhouse in this system can manage zero waste and reduce greenhouse gas (GHG) emissions and climate change.

266 citations

Journal ArticleDOI
TL;DR: GnIH in birds and mammals appears to act at all levels of the hypothalamo-pituitary-gonadal (HPG) axis, and possibly over different time-frames, and GnIH and its homologs appear to act as key neurohormones controlling vertebrate reproduction.

265 citations


Authors

Showing all 26778 results

NameH-indexPapersCitations
Dirk Inzé14964774468
Norbert Perrimon13861073505
Bobby Samir Acharya1331121100545
Eduardo Marbán12957949586
Benoît Roux12049362215
Fereidoon Shahidi11995157796
Stephen Safe11678460588
Mark A. Tarnopolsky11564442501
Robert C. Haddon11257752712
Milton H. Saier11170754496
Hans J. Vogel111126062846
Paul D. N. Hebert11153766288
Peter T. Katzmarzyk11061856484
John Campbell107115056067
Linda F. Nazar10631852092
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202368
2022391
20212,574
20202,547
20192,264
20182,155