Physical Sciences and Mathematics Commons^™

Phd Thesis (Doctorat De Spécialité): Université De Ouagadougou, 1999. Dr. Mamoudou H. Dicko. Purification Et Propriétés Physico-Chimiques Des Enzymes De Curculigo Pilosa, Gladiolus Klattianus Et Boscia Senegalensis Catalysant L'Hydrolyse Des Polysaccharides (Amidon Et Béta-Glucanes), Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

The objective of this study was the research of novel and inexpensive sources of polysaccharides degrading enzymes such as amylases and glucanases from local plants in order to justify their biotechnological applications. The isolation of two l3-amylases and an endo-1,3-ß-D-glucanase was reached using common protein purification methods such as buffer extraction, ammonium sulfate fractionation, ionexchange and gel filtration chromatographies. The methods used were simple and easily reproducible, suggesting the possibilfty of large-scale production. ln the crude extract of Curculigo pilosa tuber, only ß-amylase was detected as starch degrading enzyme and its activity was approximately 282 Uig of fresh material. The …

New Developments In A Hazard Identification Algorithm For Hormone Receptor Ligands, Steven P. Bradbury, Ovanes Mekenyan, Nina Nikolova, Stoyan Karabunarliev, Gerald T. Ankley, Bjorn Hansen

Steven P. Bradbury

Recently we described the Common REactivity PAttern (COREPA) technique to screen data sets of diverse structures for their ability to serve as ligands for steroid hormone receptors [1]. The approach identi®es and quanti®es similar global and local stereoelectronic characteristics associated with active ligands through a comparison of energeticallyreasonable conformer distributions for selected descriptors. For each stereoelectronic descriptor selected, discrete conformer distributions from a training set of ligands are evaluated and parameter ranges common for conformers from all the chemicals in the training set are identi®ed. The use of discrete partitions of parameter ranges to de®ne common reactivity patterns can, however, …

Biotransformation Of 4-Methoxyphenol In Rainbow Trout (Oncorhynchus Mykiss) Hepatic Microsomes, Steven P. Bradbury, R. Kolanczyk, P. Schmieder, T. Spizzo

Steven P. Bradbury

Rainbow trout liver microsomes were used to study the O-demethylation and ring hydroxylation of 4-methoxyphenol (4-MP) (4-hydroxyanisole) at 11 and 25°C by directly measuring the production of the primary metabolite hydroquinone (HQ), 4-methoxycatechol (4-MCAT), and additional metabolites. An HPLC method with integrated ultraviolet (UV) and electrochemical detection (ECD) was developed for metabolite identification and quantification at low concentrations. Sample handling with appropriate buffers, solvents, low temperature and light prevented loss of extremely labile metabolites. Saturation kinetics for the production of HQ via O-demethylation of 4-MP (0.66–40 mM) was never achieved, with substrate solubility being the limiting factor. The linear rate …

Jual Obat Aborsi Sidoarjo 082244058007 Obat Penggugur Kandungan, Arin Najwa, Jual Obat Aborsi Obat Penggugur Kandungan

arin najwa

Acetate Retention And Metabolism In Thehyporheic Zone Of A Mountain Stream, Michelle A. Baker

Michelle A. Baker

An in situ acetate injection was used to determine the influence of labile dissolved organic carbon (DOC) availability on microbial respiration in the hyporheic zone of a headwater stream. We added bromide as a conservative tracer and acetate as an organic substrate to the hyporheic zone of Rio Calaveras, New Mexico, via an injection well. Tracer was observed in four of eight capture wells. Three of the four wells showed increases in bromide without concurrent increases in acetate concentration, suggesting 100% acetate retention. One well had 38% acetate retention. Pore velocity and acetate retention were negatively correlated, suggesting hydrologic control …

Soil Amino Acid Utilization Among Species Of The Cyperaceae: Plant And Soil Processes, Ted K. Raab, David A. Lipson, Steven K. Scmidt, Russ K. Monson

Ted K. Raab

Amino acids are released during the decomposition of soil organic matter and have been shown to be utilized as a nitrogen source by some non-mycorrhizal species in the family Cyperaceae (the sedge family). Twelve out of 13 Cyperaceae species examined in the current study were capable of absorbing soil amino acids in the non-mycorrhizal state. With two exceptions (two species in the genus Kobresia), species from subalpine or alpine habitats exhibited lower rates of total nitrogen uptake compared to species from more temperate habitats, which is possibly explained by lower growth rates in the alpine and subalpine species and a …

The Effect Of Water Level Management On The Soils And Vegetation Of Two Coastal Louisiana Marshes, Brian J. Wilsey, K. M. Flynn, I. A. Mendelssohn

Brian J. Wilsey

Wetland degradation and loss is the result of a combination of natural causes and anthropogenic activities and is a serious problem in coastal Louisiana, where approximately 80% of the total US coastal wetland loss since the 1930’s has occurred. One method currently used to address this wetland loss problem is structural marsh management,which is the use of levees and water control structures to control hydroperiod. The effects of structural marsh management on two managed marshes in Southern Louisiana (Unit 4 of the Rockefeller Wildlife Refuge and the Fina LaTerre Mitigation Bank) were evaluated by comparing the soils and the dominant …

Temporal Changes In Purity And Specific Activity Of Tritium-Labeled 2,3,7,8-Tetrachlorodibenzo-Ρ-Dioxin: Radiopurity Model For Toxicology, Steven P. Bradbury, Joseph D. Fernandez, Philip M. Cook, Brian C. Butterworth

Steven P. Bradbury

The specific activity (S) and radiopurity (R) of tritium labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin, [3H]TCDD, were measured by gas chromatography/mass spectrometry (GC/ MS) while attempting to accurately characterize TCDD doses received by invertebrates, fish, and fish embryos during several toxicology studies conducted over a 3 year period. The [3H]TCDD sample was found to consist of six TCDD analogues involving hydrogen, deuterium, and tritium substitution at the 1,6-dibenzo-p-dioxin carbon positions and a complex mixture of impurities (with and without tritium labels). Planar aromatic impurities were identified as tolyl- TCDD adducts and appeared to result from the decay of 3H radiolabels to produce TCDD carbocations …

Derivation Of Wildlife Values For Mercury, Steven P. Bradbury, John Nichols, Jeff Swartout

Steven P. Bradbury

A procedure has been developed to estimate surface water concentrations of toxicants (“wildlife values”) that will protect the viability of wildlife populations associated with aquatic resources. This procedure was designed primarily to protect piscivorous birds and mammals from compounds that bioaccumulate in fish and was used in the Great Lakes Water Quality Initiative (GLI) to calculate wildlife values (WV) for mercury, DDT/DDE, total polychlorinated biphenyls (PCBs), and 2,3,7,8-tetrachlorodibenzodioxin (TCDD). Published in 1995, and expressed as total mercury in unfiltered water, the final wildlife value (WVf) for mercury derived in the GLI was 1300 pg Hg/L. This value was selected as …

New Testing Apparatus For Assessing Interactive Effects Of Suspended Solids And Chemical Stressors On Plankton Invertebrates, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer

Steven P. Bradbury

To better predict and interpret the responses of aquatic organisms to environmentally relevant chemical exposures, it is necessary to investigate the combined effects of physical (e.g., suspended solids) and chemical stressors. One of the limitations in investigating suspended solids–chemical interactions has been the lack of an appropriate testing system. The specific objective of the current study was to develop and assess a suspended solids testing apparatus (SSTA) for studies on the combined effects of suspended solids and chemicals on aquatic invertebrates. The SSTA was designed to permit the assessment of varying suspended solids concentrations on Daphnia magna at a constant …

Sensory And Motor Interdependence In Postural Adjustments, Gin Mccollum

Gin McCollum

The sensory reafference from a movement depends upon the movement, and the movement chosen depends upon the available senses, as demonstrated by vestibular patients who abandon certain movements. Often, one variable is assumed to be dependent whereas the other is independent; however, sensory and motor dynamics in posture are interdependent as conditions upon each other. This paper applies conditional dynamics to characterize the global structure of interdependence between sensory states and motor strategies in fast postural adjustments. The mathematical formalism incorporates rich but disparate experimental, clinical, and theoretical results about sensory and motor control of posture.

The control structures presented …

Graded Functional Activation In The Visuo-Spatial System With The Amount Of Task Demand, Patricia Carpenter, Marcel Just, Timothy Keller, William Eddy, Keith Thulborn

Marcel Adam Just

No abstract provided.

Time Course Of Fmri-Activation In Language And Spatial Networks During Sentence Comprehension, Patricia A. Carpenter, Marcel Adam Just, Timothy A. Keller, William F. Eddy, Keith R. Thulborn

Marcel Adam Just

No abstract provided.

Plasticity Of Language-Related Brain Function During Recovery From Strok, Keith R. Thulborn, Patricia A. Carpenter, Marcel Adam Just

Marcel Adam Just

No abstract provided.

Computational Modeling Of High-Level Cognition And Brain Function, Marcel Adam Just, Patricia A. Carpenter, Sashank Varma

Marcel Adam Just

No abstract provided.