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Articles 43831 - 43860 of 51624

Full-Text Articles in Life Sciences

Effects Of Non-Point Nutrient Loading On Planktonic Community Structure And Function In A Great Lakes Coastal Wetland, Brian M. Binion Jul 1995

Effects Of Non-Point Nutrient Loading On Planktonic Community Structure And Function In A Great Lakes Coastal Wetland, Brian M. Binion

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Brian M. Binion on July 26, 1995.


Water Quality Analysis Of Eastern Kentucky Reservoirs, Stephen E. Davis Iii Jul 1995

Water Quality Analysis Of Eastern Kentucky Reservoirs, Stephen E. Davis Iii

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Stephen E. Davis III on July 19, 1995.


The Feasibility Of Trophic Manipulation In Grayson Lake, Kentucky, U.S.A., Russell Walker Crawford Jul 1995

The Feasibility Of Trophic Manipulation In Grayson Lake, Kentucky, U.S.A., Russell Walker Crawford

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Masters of Science by Russell Walker Crawford on July 19, 1995.


Renal Responses To Differential Rates Of Blood Volume Expansion In The Toad, Bufo Marinus, Mark Edward Bolke Jul 1995

Renal Responses To Differential Rates Of Blood Volume Expansion In The Toad, Bufo Marinus, Mark Edward Bolke

Dissertations and Theses

Three aspects of renal function were measured in the toad, Bufo marinus (N=lO): (1) effect of rate of blood volume expansion on renal functions (UFR; GFR; urine and plasma ion concentrations; and ion excretion rates), (2) effect of hypo- and hyperosmotic blood volume expansions on renal functions, and (3) role of GFR and tubular processes in the differential response of UFR under different osmotic expansion stresses. Renal responses to differential rates of blood volume expansion have not been investigated in amphibians. Rate responses will be analyzed considering effects: ( 1) during infusion (neural, or, short term regulation of extracellular fluid …


Variation In Plasma Prostaglandin E2 Level In Mouse During Infection With Trichinella Spiralis And Trichinella Pseudospiralis, Zahra Mehdizadehkashi Jul 1995

Variation In Plasma Prostaglandin E2 Level In Mouse During Infection With Trichinella Spiralis And Trichinella Pseudospiralis, Zahra Mehdizadehkashi

Dissertations and Theses

Polymorphonuclear leukocytes infiltrate tissues in response to an inflammatory stimulus such as endotoxin or parasite products. Previous studies have shown an extensive cellular infilteration about the parasitized skeletal muscle of mouse infected with the nematode, Trichinella spiralis. Infection of the host with Trichinella pseudospiralis, on the other hand, is associated with a dramatic suppression of inflammatory cellular response. Prostaglandin Bi is a product of arachidonic acid metabolism and is synthesized by variety of cell types. Prostaglandins of the E series have been generally known to suppress inflammatory responses. In the present study, I have investigated the possible relation between plasma …


Chemical Fate Of Bunker C Fuel Oil In A Subtropical Marine Environment Following A Spill In Tampa Bay, Florida, Dana Lynn Wetzel Jul 1995

Chemical Fate Of Bunker C Fuel Oil In A Subtropical Marine Environment Following A Spill In Tampa Bay, Florida, Dana Lynn Wetzel

USF Tampa Graduate Theses and Dissertations

A hydrocarbon chemistry study was performed on sediments, oil masses and mangrove prop roots of a mangrove island in Boca Ciega Bay, Florida following a spill of Bunker C fuel oil in Tampa Bay. Normal alkane (n-alkane) and polycylic aromatic hydrocarbon (PAH) profiles were monitored for effects of degradation and weathering in these mediums for a period of one year. Initial findings indicated a loss of lower molecular weight n-alkanes and PAH's in sediments and prop roots. There was little or no loss of these low molecular weight components in the oil mass samples. Hydrocarbon profiles at the end of …


The Chemotactic Response Of Neutrophils To Components Of The Sera Of Mice Infected With Trichinella Spiralis, Sara Lynn Youngman Jul 1995

The Chemotactic Response Of Neutrophils To Components Of The Sera Of Mice Infected With Trichinella Spiralis, Sara Lynn Youngman

Dissertations and Theses

Neutrophils accumulate around Trichinella spiralis larvae encysted in skeletal muscle cells of the host. The magnitude of the neutrophil infiltration follows a pattern relating to the stage of infection of T.spiralis. This study was performed to determine if there are factors chemotactic for neutrophils present in the sera of mice infected with T.spiralis, and if present, to compare the chemotactic potential of sera from several time points during the infection. Female MRL++ mice hosted the T.spiralis infection and provided neutrophils for all experiments. The chemotactic potentials of sera were tested by placing 150 ul of serum collected …


Investigation Of The Substrate Recognition Characteristics And Kinetics Of Mammalian Mitochondrial Dna Topoisomerase I, Zeki Topcu Jul 1995

Investigation Of The Substrate Recognition Characteristics And Kinetics Of Mammalian Mitochondrial Dna Topoisomerase I, Zeki Topcu

Theses and Dissertations in Biomedical Sciences

Topoisomerases are DNA-modifying enzymes found in prokaryotes, eukaryotes, viruses and organelles such as chloroplast and mitochondria. Information about these enzymes in eukaryotic systems is mostly limited to nuclear enzymes, although our laboratory has been characterizing the biochemical and biophysical properties of the mammalian mitochondrial topoisomerases. We have determined the polarity of the attachment of mitochondrial topoisomerase I to its substrate DNA. To study the substrate preference and kinetic parameters of mitochondrial topoisomerase I, selected regions of mammalian mitochondrial DNA (mtDNA) were inserted into pGEM plasmid vectors following a series of modification and optimization experiments of currently available methods for PCR-cloning. …


Demography, Reproduction, Diet And Crop Depredation In Three Species Of Rodents In Natural And Irrigated Fields In Nigeria, Safianu Rabiu Jul 1995

Demography, Reproduction, Diet And Crop Depredation In Three Species Of Rodents In Natural And Irrigated Fields In Nigeria, Safianu Rabiu

Biological Sciences Theses & Dissertations

Rodent populations of Arvicanthis, Mastomys and Tatera were studied during July 1990 to August 1992 in both natural and irrigated savannah fields of northern Nigeria. Tatera was entirely absent from the irrigated fields. Irrigation enhanced higher rodent population densities in the magnitude of three to four times over densities in the natural field. Arvicanthis was the most abundant of the three species in both sites. Tatera was the least common in the natural site. Adult survival rates in Arvicanthis and Tatera were significantly higher than Mastomys. Survival rates of both adult and young differed between the wet and dry …


Zooplankton Community Dynamics In The Elizabeth River, Virginia, William C. Sharp Jul 1995

Zooplankton Community Dynamics In The Elizabeth River, Virginia, William C. Sharp

Biological Sciences Theses & Dissertations

Zooplankton community structure and dynamics were studied over a 12 month period in the Elizabeth River, an industrially polluted tidal river in the Chesapeake Bay estuarine system. An additional site in this estuary (Hampton Roads) was sampled for comparative purposes. Multivariate analysis indicated five distinct temporal groups occurred during the year, but there were no significant differences in spatial composition within the river. Maximum zooplankton concentrations were observed in July and lowest abundances were observed in February, March, and November. Copepods, especially Acartia species, were the most abundant components of the zooplankton community, comprising 67 to 93% of the total …


Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus On The Eastern Shore Of Virginia, John A. March Jr. Jul 1995

Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus On The Eastern Shore Of Virginia, John A. March Jr.

Biological Sciences Theses & Dissertations

The population dynamics of Oryzomys palustris, the marsh rice rat, and of Microtus pennsylvanicus, the meadow vole, were determined during a year-long mark-and-recapture study on the Eastern Shore of Virginia. Three nights of trapping per month were conducted on two live trap grids totaling 5456 total trap nights. The grids were located on Nature Conservancy land, one in Oyster, and the second at Steelman's Landing, which is east of Townsend in Northampton County Virginia. Trapped animals were evaluated using established criteria. Reproductive activity, age and sex composition, and density of the population, capture probability, survival rate, and recruitment were determined. …


In Vitro Expression Of Human Zona Pellucida Protein 3, Chih-Wei Chen Jul 1995

In Vitro Expression Of Human Zona Pellucida Protein 3, Chih-Wei Chen

Theses and Dissertations in Biomedical Sciences

Human zona pellucida protein 3 (hZP3) is the putative receptor on the zona pellucida of the mature oocyte that recognizes and binds sperm, and therefore plays a critical role in fertilization.

A full length cDNA of hZP3 (1278 bp) was amplified from the human ovary mRNA by reverse transcription-polymerase chain reaction (RT-PCR). The hZP3 cDNA was subcloned into PSK and pREP4 expression vectors. The cDNA of hZP3 was further characterized by restriction mapping, PCR, auto-sequencing and Southern blot analysis by using an internal oligonucleotide probe, and found to be identical to the one reported by J. Dean. Using autosequencing, 289 …


Identification And Characterization Of Mitochondrial Dna Variants In Alzheimer's Disease, Natasha Singh Hamblet Jul 1995

Identification And Characterization Of Mitochondrial Dna Variants In Alzheimer's Disease, Natasha Singh Hamblet

Theses and Dissertations in Biomedical Sciences

Alzheimer's Disease (AD) is a complex neurodegenerative disorder that affects a significant portion of the human population regardless of ethnicity or gender. A mitochondrial hypothesis of AD has been proposed based on a number of studies which establish altered oxidative phosphorylation (OXPHOS) and ATP synthesis in AD tissue. ATP demand is most prevalent in the brain; damage to OXPHOS could severely impair brain metabolism, thereby leading to a decline in cognitive function. Four out of five complexes in the OXPHOS pathway are partly encoded by mitochondrial DNA (mtDNA); thus, this may be a crucial site of lesions that alter brain …


The Effects Of Repulping Variables On Deinking Of Flexographic Inks, Sylvia Ciampa Jun 1995

The Effects Of Repulping Variables On Deinking Of Flexographic Inks, Sylvia Ciampa

Masters Theses

The effects of repulping variables (pH, surfactant concentration, time, and temperature) on deinking paper printed with flexographic ink were studied. A series of alcohol ethoxylate surfactants was evaluated. The one with HLB= 11.8 was selected for the majority of the study.

pH was the variable that presented the greatest effect on repulping and deinking. The brightness after repulping and the final brightness after deinking was significantly higher at pH 5 than at pH 9.

Paper was repulped for 15, 25, and 40 minutes respectively. Highest brightness after repulping and highest gain in brightness by flotation was observed after 15 minutes …


Differential Distribution Of D4 And D2 Dopamine Receptors In Rat Brain: An Autoradiographic Study Using [3H]Ym-09151-2 And [3H]Raclopride, Nancy C. Stratman Jun 1995

Differential Distribution Of D4 And D2 Dopamine Receptors In Rat Brain: An Autoradiographic Study Using [3H]Ym-09151-2 And [3H]Raclopride, Nancy C. Stratman

Masters Theses

Extrapyramidal side effects (EPS) are associated with most antipsychotics for the treatment of schizophrenia since these agents antagonize dopamine D2 receptors in the nigrostriatal pathway, a brain system that regulates motor functions. Clozapine, an atypical antipsychotic agent in that it does not produce EPS, was found to be more selective for the D4 than the D2 receptor. The purpose of this study was to locate the D4 receptor in rat brain by autoradiographic comparison studies with [3H]YM-09151-2, a D2 , D3, and D4 radioligand, to [3H]raclopride, a D …


The Interaction Of Coated Paper Surfaces And Water- And Solvent-Based Rotogravure Printing Inks, Tanja M. Gnad Jun 1995

The Interaction Of Coated Paper Surfaces And Water- And Solvent-Based Rotogravure Printing Inks, Tanja M. Gnad

Masters Theses

The print quality of 24 different coating formulations was studied when printing with both water- and solvent-based rotogravure ink. Coating was done on a Cylindrical Laboratory Coater (CLC). The coated paper samples were supercalendered to achieve a smooth surface which is necessary when printing with rotogravure. The supercalendered coated paper samples where tested for optical and surface properties and also printed with water-based and solvent-based ink on a Moser Gravure Proof Press. The print quality of the printed samples was quantified by image analysis. The results showed that fine ground calcium carbonate gave the lowest percent bridging between ink dots, …


The Excitatory Amino Acid (Eaa) Antagonist Dextrorphan Increases Morphine Antinociception In Spinally Transected Rats, Francisco Q. Rhein Jun 1995

The Excitatory Amino Acid (Eaa) Antagonist Dextrorphan Increases Morphine Antinociception In Spinally Transected Rats, Francisco Q. Rhein

Honors Theses

No abstract provided.


A Model Of Cytomegalovirus Association With The Development Of Heart Graft Atherosclerosis, Evan Skowronski Jun 1995

A Model Of Cytomegalovirus Association With The Development Of Heart Graft Atherosclerosis, Evan Skowronski

Loma Linda University Electronic Theses, Dissertations & Projects

The development of graft atherosclerosis in heart transplant recipients has been associated with the development of post-transplant cytomegalovirus infection. The mechanism of this involvement, however, remains unclear. I undertook a study to determine the role of cytomegalovirus in the development of graft atherosclerosis. First, a rapid method of detecting cytomegalovirus based on capillary polymerase chain reaction and gel electrophoresis was employed to determine the presence of cytomegalovirus in a wide variety of clinical samples. Detection of cytomegalovirus is a lengthy procedure under normal conditions, and timely detection of cytomegalovirus in transplant recipients may allow intervention early enough to block the …


Ornithine Decarboxylase And Polyamines In Perinatal Hypoxia, Satyaseelan Packianathan Jun 1995

Ornithine Decarboxylase And Polyamines In Perinatal Hypoxia, Satyaseelan Packianathan

Loma Linda University Electronic Theses, Dissertations & Projects

Hypoxic and hypoxic/ischemic episodes contribute to various neurological aberrations, learning disabilities, et cetera in surviving infants. Despite major advances in understanding the pathophysiology of hypoxia, the cellular basis for hypoxic-mediated injury remains poorly understood. In addition, the role of developmentally essential enzymes vis á vis their contributions, or lack thereof, to hypoxic-mediated injury has not been adequately investigated. In the series of studies comprising this dissertation, we tested the hypothesis that acute and/or chronic hypoxia affect the activity of omithine decarboxylase (ODC; E.C. 4.1.1.17), the developmentally essential enzyme in polyamine biosynthesis, in the fetal and newborn rat brain. Fetal and …


Periodontal Repair In Dogs : Evaluation Of Rhbmp-2 Carriers, Lauralee Nygaard Jun 1995

Periodontal Repair In Dogs : Evaluation Of Rhbmp-2 Carriers, Lauralee Nygaard

Loma Linda University Electronic Theses, Dissertations & Projects

This study evaluated candidate carriers for recombinant human bone morphogenic protein-2 (rhBMP-2) in periodontal reconstructive surgery.

Canine demineralized bone matrix (DBM), bovine inorganic crystallene bone matrix (Bio-Oss), bovine derived microfibrillar collagen matrix (Helistat), poly (D,L-lactide-coglycolide) micropaiticles (PLGA), and polylactic acid granules (Drilac) were used with rhBMP-2 (20 (µg/100 µl implant volume) in routine critical size canine supraalveolar periodontal defects. Contralateral defects in six beagle dogs were randomly assigned to receive: DBM/rhBMP-2, DBM-control, Bio-Oss/rhBMP-2, Helistat/rhBMP-2, PLGA/rhBMP-2, or Drilac/rhBMP-2, all with autologous blood except for Helistat and PLGA. Animals were sacrificed eight weeks post-surgery and block sections of the defects were processed …


Maturational Changes In Cerebrovascular Ca2+ In Hypoxia, Shelley D. Zurcher Jun 1995

Maturational Changes In Cerebrovascular Ca2+ In Hypoxia, Shelley D. Zurcher

Loma Linda University Electronic Theses, Dissertations & Projects

The clinical consequences of hypoxic cerebrovascular insults in the neonate, can be severe. It would therefore be valuable to understand the mechanisms of hypoxia-induced cerebrovasodilation. These studies were done in ovine middle cerebral and common carotid arteries to help elucidate the mechanisms through which calcium handling is involved in hypoxic cerebral vasodilation, comparing newborns and adults. The present studies demonstrate that calcium sensitivity (measured by the pD2) and the maximum contractile response to calcium increased with maturation. In addition, hypoxia depressed the maximum response to calcium and this effect was greater in adult than in newborn arteries. These results suggest …


Modulation Of Neutrophil Functions By Neurotransmitters Implicated In Stress, Chok Ping Wan Jun 1995

Modulation Of Neutrophil Functions By Neurotransmitters Implicated In Stress, Chok Ping Wan

Loma Linda University Electronic Theses, Dissertations & Projects

Stress has long been implicated in immune modulation. People under chronic stress have no change in the circulating basal levels of catecholamines while plasma levels of neuropeptide Y (NPY) are significantly increased. Sympathetic nerve fibers with NPY have been found to innervate immune organs. It was hypothesized that NPY might be a mediator in immune modulation in people under chronic stress. Human neutrophils were used as a model to study the effects of NPY alone or together with norepinephrine on the immune system. We now report that NPY modulates oxidative burst (OB) triggered by zymosan in human neutrophils while it …


Regulation Of The Insulin-Like Growth Factor System By Retinoic Acid In Human Osteoblast Cells, Yuehua Zhou Jun 1995

Regulation Of The Insulin-Like Growth Factor System By Retinoic Acid In Human Osteoblast Cells, Yuehua Zhou

Loma Linda University Electronic Theses, Dissertations & Projects

Retinoic acid (RA) is an important regulator of growth and differentiation in many cell types, including bone. However, its effects on human osteoblast cell growth and differentiation have not been well studied. Therefore, I investigated the effect of RA on proliferation and differentiation of normal human bone cells (HBCs) and human osteosarcoma, SaOS-2 cells. RA decreased baseline as well as serum-stimulated proliferation in normal HBCs. To determine the effect of RA on differentiation, expression of several osteoblastic differentiation markers were studied. RA decreased type I procollagen mRNA levels and l,25(OH)2D3-stimulated osteocalcin and alkaline phosphatase (ALP) mRNA …


Experimental Peri-Implant Tissue Breakdown In Rhesus Monkeys, Oliver Hanisch Jun 1995

Experimental Peri-Implant Tissue Breakdown In Rhesus Monkeys, Oliver Hanisch

Loma Linda University Electronic Theses, Dissertations & Projects

The aim of this investigation was to characterize peri-implant tissue breakdown following ligature-induced plaque accumulation around osseointegrated implants in the rhesus monkey. Two hydroxyapatite-coated cylindrical implants were inserted bilaterally in the second premolar and first molar region of both mandible and maxilla in four non-human primates (Macaca mulatto). The implants were left submerged to osseointegrate for one year. Eight weeks after healing abutment connection, a two-month plaque control program was initiated. At the end of this period, clinical and radiographic recordings were carried out, and peri-implant subgingival microbial samples were obtained (baseline). Subsequently, cotton ligatures were placed around …


Physiologically-Based Pharmacokinetic Modeling Of Skin Absorption Using Dermal Subcompartments, Richard L. Bookout Jr. Jun 1995

Physiologically-Based Pharmacokinetic Modeling Of Skin Absorption Using Dermal Subcompartments, Richard L. Bookout Jr.

Theses and Dissertations

Dermal penetration of chemicals and drugs is important to both toxicologists and pharmacologists. Drug developers try to enhance and environmental professionals try to limit penetration of chemicals through the skin. Both can use predictive biologically-based mathematical models to assist in understanding the processes involved. When these models are based on physiological and biochemical parameters which can be measured in the laboratory, they can be extremely useful. Appropriately validated models based on first principles can be predictive of human exposures when the processes involved are adequately understood. In this thesis we develop four new physiologically-based pharmacokinetic (PBPK) models to predict blood …


Effect Of Ototoxic Drugs On The Amphibian Auditory System: Injection Of Gentamicin Sulfate Into Anuran Otic Capsules And Recovery Of Thresholds, Michael Patrick Brown May 1995

Effect Of Ototoxic Drugs On The Amphibian Auditory System: Injection Of Gentamicin Sulfate Into Anuran Otic Capsules And Recovery Of Thresholds, Michael Patrick Brown

Dissertations and Theses

Hair cell trauma from aminoglycosides, which may lead to permanent loss of hair cells in mammals, was studied physiologically in frogs by measuring an auditory evoked potential (AEP) in Rana pipiens. The AEP was evaluated in order to measure threshold shift (TS) and recovery from TS after the administration of the aminoglycoside antibiotic, gentamicin. To obtain an AEP, chronic electrodes were implanted into the cranium near the cochlear nucleus. The frogs were then exposed to frequency-specific narrow band "clicks" which included a single period 1 kHz sinewave, and a computer synthesized high frequency and low frequency click. Amphibians have two …


Transitions In Masculinity And Hemingway's Developed "Code", Daniel Polk May 1995

Transitions In Masculinity And Hemingway's Developed "Code", Daniel Polk

Honors Theses

The "Hemingway Code" is much more than two words that fit nicely together for a scholar's usage; the words signify a much deeper championing of masculinity, almost a haunting presence. For Ernest Hemingway living life every day, every moment with its fullest masculine fervor, became an obsession, a never-ending quest to be at one with the attitude of never complaining, never crying out, panicking, thinking too much, or regretting. To live a manly life in a series of tactical victories, performed with steadfast ritualistic mannerisms, is to embody masculinity, and therefore the "Hemingway Code."


Post-Glacial Vegetational History Of The Great Bog, Belgrade, Maine, John Dawson May 1995

Post-Glacial Vegetational History Of The Great Bog, Belgrade, Maine, John Dawson

Senior Scholar Papers

A 6-m vibracore taken from the Great Bog in Belgrade, Maine, was sampled for pollen analysis at 10-cm intervals. Samples were processed in the laboratory using standard techniques developed by Faegri and Iversen. The sediment in the sample was reduced to a residue of pollen which was mounted on microscope slides. A minimum of 300 pollen grains was identified and counted at each level using a compound microscope at 400x magnification. Five radiocarbon dates were taken from the core at stratigraphic boundaries. Lastly, pollen concentration and pollen accumulation rates were calculated. The uppermost 3.8 m of the core is fine …


Use Of Microprojectile Bombardment In Transient Expression Assays To Analyze Protochlorophyllide Reductase Gene Expression In Greening Maize Seedling Leaf Cells, Jennifer J. Marden May 1995

Use Of Microprojectile Bombardment In Transient Expression Assays To Analyze Protochlorophyllide Reductase Gene Expression In Greening Maize Seedling Leaf Cells, Jennifer J. Marden

Senior Scholar Papers

In young cells of leaf meristems the progenitors of chloroplasts are small organelles known as proplastids, which divide and differentiate into chloroplasts. However, in the absence of light, proplastids undergo a different sequence of development and become etioplasts. When light is supplied to etiolated plants during the "greening" process, etioplasts differentiate into chloroplasts containing chlorophyll. An important light dependent step in chlorophyll biosynthesis is the photoreduction of protochlorophyllide to chlorophyllide by the NADPH:protochlorophyllide reductase (PCR) enzyme. This enzyme is present at high activity only in etiolated tissue and during early stages of light-induced chlorophyll synthesis. The enzyme and its corresponding …


Chemical Characterization Of Condensate From Steam Classified Municipal Solid Waste, Gregory C. Batson May 1995

Chemical Characterization Of Condensate From Steam Classified Municipal Solid Waste, Gregory C. Batson

Honors Capstone Projects and Theses

No abstract provided.