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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Toxicity and adsorbance abilities of Alcell lignin to bacteria

Sitnikov, Dmitri. January 1999 (has links)
AlcellRTMlignin has been used commercially in adhesive preparation and brake pad linings and experimentally in animal feeds to reduce or eliminate diarrheal attacks in farm animals. Our study dealt with elucidating the antibacterial effect of AlcellRTMlignin. It would appear that adsorbance of E. coli cells to AlcellRTMlignin particles is not essential for destruction of the organism. / The antibacterial activity was delayed by the inclusion of Mg 2+ ions in the AlcellRTMlignin filtrate or in the enumeration medium (BHIA). Addition of bile salts to the enumeration medium (BHIA) enhanced the culturability loss of E. coli cells suspended in the filtrate of AlcellRTMlignin. Using FTIR methodology, it appears, that compounds of AlcellRTMlignin affect phospholipid-phospholipid and/or phospholipid-protein interactions in bacterial membranes, causing the patching of membrane phospholipids and proteins. / Additional studies are necessary to evaluate interactions of compounds of AlcellRTMlignin with bacterial cells.
202

Molecular genetic manipulations in the white-rot fungus Trametes versicolor

DosSantos, Gary P. January 2000 (has links)
Although several enzymes presumed to be part of the delignification/kraft pulp biobleaching system of the white-rot basidiomycete Trametes versicolor have been studied, characterized, and even exploited as pulp treatments, the complete system remains poorly understood. Little is known about which enzymes are essential for delignification, how they are regulated, or whether there remain unknown enzymes essential to wood decay in this system. Auxotrophic mutants of T. versicolor 52J were developed and characterized. Plasmid pUC18 was complemented with the T. versicolor 52J genome to create a gene library. Transformation with this plasmid-gene library converted argB and ade2 auxotrophs of T. versicolor 52J to prototrophy. Attempts to rescue the plasmids responsible were unsuccessful. Several different pre-existing plasmid constructs were examined for their potential as selectable markers on the fungus. One of these, pGPhT, worked well at conferring phleomycin resistance. Given that there are now available partial or complete sequences for four T. versicolor laccases, the single cellobiose dehydrogenase, and a lignin peroxidase isozyme, these genetic tools should be very useful in dissecting the mechanisms of white-rot delignification.
203

Biochemical and environmental controls of litter decomposition

Sariyildiz, Temel January 2000 (has links)
No description available.
204

Selective hydrogenation of lignin-derived model compounds to produce nylon 6 precursors

Zhou, Xiaojuan 12 January 2015 (has links)
This study investigated the conversion of monomeric lignin fragments into cyclohexanols for use as a source of lignin-derived monomers for renewable Nylon 6 production. Lignin-derived monomeric phenolic species was transformed to their cyclohexanol analogs via selective catalytic hydrogenation. A fixed-bed flow reactor was used to evaluate the selective hydrogenation of individual model phenolic species (guaiacol, 4-methylguaiacol or diphenyl ether). The catalyst composition studied was Ni/SiO₂, which was previously shown to form cyclohexanol as an intermediate from phenol. A primary focus was on tuning the reaction conditions to form desired products, while avoiding the formation of bicyclic species which can be precursors to catalyst deactivation, or fully hydrogenated products of lower value. Reaction pathways of guaiacol, 4-methylguaiacol and diphenyl ether were studied. Major products obtained from guaiacol, 4-methylguaiacol and diphenyl ether reactions were 2-methoxycyclohexanone, 4-methylcyclohexanol and cyclohexanol, respectively. Spent catalyst was analyzed for extent of deactivation.
205

Hormonal regulation of cell development and polyphenol biosynthesis in cultured Populus trichocarpa cells /

Hoffman, Sister Angela, January 1989 (has links)
Thesis (Ph. D.)--Oregon Graduate Center, 1989.
206

Cellulose digestibility, ethanol yield, and lignin recovery from corn stover fractionated by a two-stage dilute-acid and dilute-alkaline process

Joiner, David B.. January 2005 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.
207

Die Röntgenmikroanalyse von Lignin als Untersuchungsmethode für Holz und Holzwerkstoffe /

Schindel, Klaus. January 1998 (has links)
Universiẗat, Fak. f. Forstwiss. u. Waldökologie, Diss.--Göttingen, 1999.
208

Evaluation of transgenes for stress tolerance, lignin modification, and growth enhancement in poplar /

Elias, Ani Anna. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 115-126). Also available on the World Wide Web.
209

Functional decreases in hydraulic and mechanical properties of field-grown transgenic poplar trees caused by modification of the lignin synthesis pathway through downregulation of the 4-coumarate:coenzyme A ligase gene /

Voelker, Steven L. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 105-116). Also available on the World Wide Web.
210

Structure and reactivity of dissolved organic matter as determined by ultra-high resulution [i.e. resolution] electrospray ionization mass spectrometry

Kim, Sunghwan, January 2003 (has links)
Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xix, 184 p.; also contains graphics (some col.). Includes abstract and vita. Advisor: Patrick G. Hatcher, Dept. of Chemistry. Includes bibliographical references (p. 168-184).

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