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1995

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Articles 181 - 210 of 324

Full-Text Articles in Biology

The Effects Of Dietary Vitamin E Supplementation On Platelet Aggregation And Plasma Oxidized Low Density Lipoprotein In Hypercholesterolemic Rats, Russell W. Thurman Apr 1995

The Effects Of Dietary Vitamin E Supplementation On Platelet Aggregation And Plasma Oxidized Low Density Lipoprotein In Hypercholesterolemic Rats, Russell W. Thurman

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 by Russell W. Thurman on April 28, 1995.


Phytoplankton In Mt. St. Helens Lakes, Washington, Cynthia Fay Baker Apr 1995

Phytoplankton In Mt. St. Helens Lakes, Washington, Cynthia Fay Baker

Dissertations and Theses

Phytoplankton communities in fifteen lakes in the Mt. St. Helens area were surveyed to assess the abundance and species present. Eleven of the lakes were inside the blast zone of the 1980 eruption and four were located outside the blast zone as a comparison. The hypothesis is that lakes will cluster together based on the algal species present and that some algae will be correlated with certain environmental conditions. A cluster analysis was performed to determine if the lakes would group together based on algal abundance. There did not appear to be any distinct clustering among the study lakes, but …


Alterations In Mdck And Llc-Pk1 Cells Exposed To Oxalate And Calcium Oxalate Monohydrate Crystals, R. L. Hackett, P. N. Shevock, S. R. Khan Apr 1995

Alterations In Mdck And Llc-Pk1 Cells Exposed To Oxalate And Calcium Oxalate Monohydrate Crystals, R. L. Hackett, P. N. Shevock, S. R. Khan

Scanning Microscopy

Structural analysis of human kidney stones reveals the presence of cellular membranes and other cell fragments. Experimentally, calcium oxalate crystallization is facilitated when an exogenous nephrotoxin is given with ethylene glycol, thus providing cellular degradation products to act as heterogenous nuclei. In this report, we tested whether oxalate alone could act as a cell toxin capable of producing damaged cells without the presence of an exogenous agent. Cultured LLC-PK1 and MDCK cells, when exposed to 1.0 mmol KOx, a concentration at the limit of metastability for calcium oxalate nucleation, were severely damaged as measured by specific lactate dehydrogenase (LDH) …


Radiation Nephropathy: A Review, M. E. C. Robbins, S. M. Bonsib Apr 1995

Radiation Nephropathy: A Review, M. E. C. Robbins, S. M. Bonsib

Scanning Microscopy

The marked radiosensitivity of renal tissue represents a limitation on the total radiotherapeutic dose that safely can be applied to treatment volumes that include the kidneys. Radiation nephropathy is characterized by a progressive reduction in renal hemodynamics associated with a severe anemia. The latter is often normochromic normocytic in character, but can progress to a microangiopathic hemolytic anemia. The pathogenic mechanisms responsible for the development of radiation nephropathy remain ill-defined. Experimental studies which allow serial determinations of functional, morphologic, and cell kinetic radiation-induced changes indicate that primarily glomerular but also tubular alterations occur in the primary stages of radiation nephropathy. …


A New Scanning Electron Microscopy Approach To The Quantification Of Bone Mineral Distribution: Backscattered Electron Image Grey-Levels Correlated To Calcium Kα-Line Intensities, P. Roschger, H. Plenk Jr., K. Klaushofer, J. Eschberger Apr 1995

A New Scanning Electron Microscopy Approach To The Quantification Of Bone Mineral Distribution: Backscattered Electron Image Grey-Levels Correlated To Calcium Kα-Line Intensities, P. Roschger, H. Plenk Jr., K. Klaushofer, J. Eschberger

Scanning Microscopy

The introduction of backscattered electron (BSE) imaging in scanning electron microscopy (SEM) has led to new possibilities for the evaluation of mineral distributions in bone on a microscopic level. The different grey-levels seen in the BSE-images can be used as a measure for the local mineral content of bone. In order to calibrate these BSE-grey-levels (BSE-GL) and correlate them to mineral contents, various attempts, using reference samples with known weighted mean atomic number and/or using simulated bone tissues with known hydroxyapatite concentrations, have been made. In contrast, a new approach is presented here based on measurements of the X-ray intensities …


Carriage Rates Of The Nosocomial Pathogen Staphylococcus Aureus In Hospital Workers, Mark Peterson Apr 1995

Carriage Rates Of The Nosocomial Pathogen Staphylococcus Aureus In Hospital Workers, Mark Peterson

Capstone Research Projects

In the 1950s, Staphylococcus aureus caused a worldwide epidemic of hospital acquired infections (nosocomial infections). By so doing, this bacterium forced nosocomial infections to be recognized as a major problem in the health care system. In that decade, it was discovered that Staphylococcus aureus is vectored by nurses in three different manners, and that carriage rates increase with length of clinical exposure to sources of the bacteria in the hospital environment.

Once subdued by antibiotics, multiple drug resistant strains of Staphylococcus aureus are again causing major nosocomial problems. In 1989, Cookson reported that a direct relationship exists between the degree …


Characterization And Expression Of Pseudomonas Fluorescens L-Arabinose Dehydrogenase: Genetic Elements In Pseudomonas Putida, Carol M. Wierenga Apr 1995

Characterization And Expression Of Pseudomonas Fluorescens L-Arabinose Dehydrogenase: Genetic Elements In Pseudomonas Putida, Carol M. Wierenga

Masters Theses

An assay based on the spectrophotometeric properties of NAD/NADH was developed to detect the degradation of L-arabinose to L-arabinolactone. This assay was used to determine the expression of the L-arabinose utilization genes contained in Pseudomonas fluorescens and in the plasmid, designated pPZ221, contained in Pseudomonas putida. The results from this assay, in conjunction with various growth kinetics, indicate that pPZ221 is inducible and repressible for L-arabinose utilization. Thus, the P. fluorescens chromosomal insert in pPZ221 for L-arabinose utilization does appear to contain the regulatory genes necessary for controlling the expression of an L-arabinose operon.


Gold Coating Of Respiratory Cilia For Scanning Electron Microscopy, E. Toskala, J. Nuutinen, M. Rautiainen, A. Pelttari Mar 1995

Gold Coating Of Respiratory Cilia For Scanning Electron Microscopy, E. Toskala, J. Nuutinen, M. Rautiainen, A. Pelttari

Scanning Microscopy

The optimal thickness of gold coating of cilia for scanning electron microscopy was studied using respiratory mucosa obtained from pigs. We tested 8 different coating times, from 10 seconds to 4 minutes, which resulted in gold layer thicknesses varying from 16 ± 1 nm to 100 ± 3 nm. The thickness of the gold layer with a coating time of 60 seconds and voltage of 2.5 kV was 43 ± 5 nm. This thickness of gold layer gave good image quality without causing any electric charging. With thinner gold films, the amount of electric charging increased. When the coating time …


Early Elemental And Ionic Changes In Cultured Cells After Stimulation With Epidermal Growth Factor, Julian E. Beesley, Simon R. Hall, Martin J. Page, Karen Affleck Mar 1995

Early Elemental And Ionic Changes In Cultured Cells After Stimulation With Epidermal Growth Factor, Julian E. Beesley, Simon R. Hall, Martin J. Page, Karen Affleck

Scanning Microscopy

Stimulation of A43 l cells (a human vulval epidermal cell line) with 50 ng/ml of epidermal growth factor (EGF) in the presence of 1. 7 mM extracellular calcium produced a sharp and sustained rise in intracellular ionic Ca2+, increased elemental Na, decreased K and a rise in Ca. In the absence of extracellular calcium, the initial Ca2+ rise remained but the sustained elevation of intracellular Ca2+ was abolished, Na and K fluxes were variable and the Ca did not change. Increased Na and decreased K was marked at 2 minutes and returned to the control value after 60 minutes. The …


Scanning Electron Microscopic Observation Of Dark Cells After Streptomycin Perfusion Of The Vestibule In Guinea Pigs, Xianxi Ge, John J. Shea Jr. Mar 1995

Scanning Electron Microscopic Observation Of Dark Cells After Streptomycin Perfusion Of The Vestibule In Guinea Pigs, Xianxi Ge, John J. Shea Jr.

Scanning Microscopy

Hearing has been stabilized in the majority of patients studied in the treatment of Meniere's disease with streptomycin. This observation suggests that effects of streptomycin may ameliorate endolymphatic hydrops, possibly by attenuating the activity of secretory tissue. The purpose of this study is to observe the dark cells of the utricle in guinea pigs after streptomycin perfusion of the vestibule. Twelve pigmented guinea pigs weighing 250-350 grams were used in this study. The vestibules in five guinea pigs were perfused monolaterally with 150 μg of streptomycin in artificial perilymph and, in seven, the vestibules were perfused only with artificial perilymph …


The Effects Of Diethyldithiocarbamate (Ddc) On The Astrocytic Cytoskeleton, Mary F. Mcmanus, Louis D. Trombetta Mar 1995

The Effects Of Diethyldithiocarbamate (Ddc) On The Astrocytic Cytoskeleton, Mary F. Mcmanus, Louis D. Trombetta

Scanning Microscopy

The dithiocarbamates are a group of compounds that are used extensively in industry, agriculture and medicine. Exposure to these compounds has caused deleterious effects to both the central and peripheral nervous systems. Cultured rat hippocampal astroglia treated with 35 μg/ml diethyldithiocarbamate (DDC) in media were studied for alterations to the cytoskeleton. Examination by both immunohistochemistry and scanning electron microscopy revealed disruption of the cytoskeletal elements. This occurred in a progressive time-dependent manner. Electrophoretic patterns demonstrated two cytoskeletal protein alterations. The microtubular protein, β-tubulin, appeared to have an altered mobility while the major intermediate filament protein, glial fibrillary acidic protein (GF …


Gold, Electron Microscopy, And Cancer Therapy, James F. Hainfeld Mar 1995

Gold, Electron Microscopy, And Cancer Therapy, James F. Hainfeld

Scanning Microscopy

Radioactive gold has properties suitable for radiotherapy and can provide lethal irradiation to cells. If the gold is conjugated to a targeting molecule, such as an antibody, it may be possible to specifically deliver the dose to tumor cells. Various gold particles are possible candidates and include gold colloids with adsorption of antibodies or gold clusters with covalent attachment. Different sizes of gold particles are available and some may be preferred for certain situations. Problems with intravenous injection and in vivo delivery are numerous, and a more tractable application is the direct instillation into the urinary bladder of radiogold immunoconjugates …


Swift Heavy Ion Induced Electron Emission From Solids, Hermann Rothard Mar 1995

Swift Heavy Ion Induced Electron Emission From Solids, Hermann Rothard

Scanning Microscopy

Quite a number of experiments have been performed on electron emission from solids induced by slow (projectile velocity Vp < 1 atomic unit) or medium velocity heavy ions (projectile energy Ep < 1 MeV/u). Only a few experiments have been made with fast heavy ions (projectile atomic number Zp > 8, Ep > 2 MeV/u) concerning either electron emission yields -y, or double differential electron energy spectra d2n(0)/dEd0 as a function of the observation angle 0. We present the results obtained so far on electron emission induced by fast (Ep > 2 MeV/u) heavy ions (Zp ~ 6). Topics discussed include experimental results for electron yields, -energy and -angular distributions and channelling phenomena as well as the theoretical approaches. We also present new results from recent studies on the evolution of electron yields …


Semiquantitative Analysis By Scanning Electron Microscopy Of Cochlear Hair Cell Damage By Ototoxic Drugs, Takehisa Saito, Yasuhiro Manabe, Noriyuki Honda, Takechiyo Yamada, Takehito Yamamoto, Hitoshi Saito Mar 1995

Semiquantitative Analysis By Scanning Electron Microscopy Of Cochlear Hair Cell Damage By Ototoxic Drugs, Takehisa Saito, Yasuhiro Manabe, Noriyuki Honda, Takechiyo Yamada, Takehito Yamamoto, Hitoshi Saito

Scanning Microscopy

The ototoxicity of cisplatin and carboplatin in the organ of Corti of the guinea pig was evaluated semiquantitatively. Damage of the stereocilia of outer hair cells (OHCs) observed by scanning electron microscopy (SEM) was classified into normal, grade 1 (10-50% loss of stereocilia), grade 2 (less than 50% remaining stereocilia), or grade 3 (missing stereocilia). The OHCs observed by light microscopy (LM) were classified as remaining or missing cells. Fifty OHCs of each row in the middle part of each turn of the cochlea were counted (a total of 150 cells per turn). Guinea pigs were administered 5 mg/kg of …


Structure Of The First C2 Domain Of Synaptotagmin I: A Novel Ca(2+)/Phospholipid-Binding Fold, R. Bryan Sutton, Bazbek A. Davletov, Albert M. Berghuis, Thomas C. Sudhof, Stephen R. Sprang Mar 1995

Structure Of The First C2 Domain Of Synaptotagmin I: A Novel Ca(2+)/Phospholipid-Binding Fold, R. Bryan Sutton, Bazbek A. Davletov, Albert M. Berghuis, Thomas C. Sudhof, Stephen R. Sprang

Biological Sciences Faculty Publications

C2 domains are regulatory sequence motifs that occur widely in nature. Synaptotagmin I, a synaptic vesicle protein involved in the Ca2+ regulation of exocytosis, contains two C2 domains, the first of which acts as a Ca2+ sensor. We now describe the three-dimensional structure of this C2 domain at 1.9 Å resolution in both the Ca2+-bound and Ca2+-free forms. The C2 polypeptide forms an eight-stranded β sandwich constructed around a conserved four-stranded motif designated as a C2 key. Ca2+ binds in a cup-shaped depression between two polypeptide loops located …


Comparison Of Cell Sediment And Surface Grown "Test Plaque" Using Scanning Electron Microscopy, S. M. Mccormack, C. M. D. Maran, K. M. Scott-Anne, D. T. Zero Mar 1995

Comparison Of Cell Sediment And Surface Grown "Test Plaque" Using Scanning Electron Microscopy, S. M. Mccormack, C. M. D. Maran, K. M. Scott-Anne, D. T. Zero

Scanning Microscopy

Scanning electron microscopy was used to compare the morphology, integrity and distribution of bacterial cells in a test plaque grown on the surface of enamel with that of the cell sediment plaque routinely used in a short-term intraoral caries model. Cultures of S. mutans IB-1600 or S. sobrinus 6715-13 were grown in complex media supplemented with either 2.0% sucrose (glucan plaque) or 0.2 % glucose (non-glucan plaque). Cell sediment (CS) plaque was prepared by centrifuging the cultures after incubation, recovering the cell sediment, and spreading it on Metricel membrane filter paper. Surface grown (SG) plaque was prepared by suspending saliva-coated …


Effect Of Sodium Saccharin On The Neonatal Rat Bladder, Samuel M. Cohen, Martin Cano, Margaret K. St. John, Emily M. Garland, Mohamad Khachab, Leon B. Ellwein Mar 1995

Effect Of Sodium Saccharin On The Neonatal Rat Bladder, Samuel M. Cohen, Martin Cano, Margaret K. St. John, Emily M. Garland, Mohamad Khachab, Leon B. Ellwein

Scanning Microscopy

In a two-generation bioassay, high doses of dietary sodium saccharin (NaSac) produce bladder carcinoma in rats, whereas acid saccharin (HSac) does not effect the urothelium. NaSac and HSac administered as 5% of the diet to F0 Sprague-Dawley (SD) and F344 rats, continued through to the weaned male rats for ten additional weeks. Control 3H-thymidine labeling index (LI) was high prior to and at birth (approximately 11%), declining rapidly by weaning (to < 0.2). Neither NaSac nor HSac increased proliferation through 7 days of age. NaSac increased the proliferation rate at later times, whereas HSac did not. The LI decreased to control levels in NaSac-fed rats switched to control diet after weaning and increased in control-fed rats switched to NaSac after birth or weaning. In a second experiment, 5% NaSac did not affect urothelial morphology of SD rats through 7 days. By 21 days post-birth, urothelial hyperplasia occurred in NaSac-fed rat. The LI in treated versus control was similar through gestation, with a slight difference by 7 days. LI was significantly different by 21 days post-birth, but was similar between males and females. These results provide additional evidence for the increased cell proliferative effects of NaSac during the neonatal period, but not during gestation.


Three-Dimensional Configuration Of Crypts Of Different Types Of Colorectal Adenomas, Keijiro Araki, Takuro Ogata Mar 1995

Three-Dimensional Configuration Of Crypts Of Different Types Of Colorectal Adenomas, Keijiro Araki, Takuro Ogata

Scanning Microscopy

The three-dimensional configuration of isolated crypts of normal human colonic mucosa and colorectal adenomas was examined by scanning electron microscopy. For isolation of the crypts, the digestion method with HCl was used for formalin fixed tissues, and the separation method with ethylenediaminetetraacetic acid (EDT A) following ultrasonication was applied to fresh tissues. In a comparative study, the NaOH cell-maceration method, which visualized the sub-basal laminal collagen sheath, was applied. The isolated crypts from the normal colon were visualized as a single straight tubule resembling a test tube. Most isolated crypts of the tubular adenomas were visualized as elongated fan-like structures …


Cell Surface Changes Of Hemopoietic Cells During Normal And Leukemic Differentiation: An Immuno-Scanning Electron Microscopy Study, D. Soligo, E. P. De Harven, N. Quirici, L. Caneva, G. Lambertenghi Deliliers Mar 1995

Cell Surface Changes Of Hemopoietic Cells During Normal And Leukemic Differentiation: An Immuno-Scanning Electron Microscopy Study, D. Soligo, E. P. De Harven, N. Quirici, L. Caneva, G. Lambertenghi Deliliers

Scanning Microscopy

Hemopoietic cells display a wide range of cell surface antigens which are either lineage specific or acquired during differentiation. Monoclonal antibodies can be used, in conjunction with colloidal gold markers, to identify under the scanning electron microscopy (SEM) at the single cell level, specific lineage or maturation stages in the hemopoietic bone marrow. Normal bone marrow cells, either gradient separated or purified by immuno-magnetic methods and leukemic cell samples, which can be considered as "frozen" stages of hemopoietic differentiation, have been studied with this method. Typical cell surface morphologies, which characterize immature progenitor cells and cells committed or differentiated towards …


Etiology Of Calcium Oxalate Nephrolithiasis In Rats. I. Can This Be A Model For Human Stone Formation?, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, R. De Water, J. C. Romijn, C. F. Verkoelen, L. C. Cao, F. H. Schröder Mar 1995

Etiology Of Calcium Oxalate Nephrolithiasis In Rats. I. Can This Be A Model For Human Stone Formation?, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, R. De Water, J. C. Romijn, C. F. Verkoelen, L. C. Cao, F. H. Schröder

Scanning Microscopy

Crystal retention is studied in a rat-model system as a possible mechanism for the etiology of human nephrolithiasis. A crystal-inducing diet (CID) of ethylene glycol plus NH4Cl in their drinking-water is offered to healthy rats to generate intratubular crystals. Subsequently, the fate of retained crystals is investigated by allowing the rats a tissue recovery/crystalluria phase for three, five and ten days, respectively, on normal drinking water.

The process of exotubulosis is observed in cortex and medulla of aldehyde-fixed kidneys after three days recovery. After five days, crystals are predominantly seen there in the interstitium. After ten days, cortex …


Etiology Of Calcium Oxalate Nephrolithiasis In Rats. Ii. The Role Of The Papilla In Stone Formation, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, R. De Water, J. C. Romijn, C. F. Verkoelen, L. C. Cao, J. M. Van 'T Noordende, F. H. Schröder Mar 1995

Etiology Of Calcium Oxalate Nephrolithiasis In Rats. Ii. The Role Of The Papilla In Stone Formation, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, R. De Water, J. C. Romijn, C. F. Verkoelen, L. C. Cao, J. M. Van 'T Noordende, F. H. Schröder

Scanning Microscopy

In kidneys of healthy rats submitted to a crystal-inducing diet (CID) with ethylene glycol (EG) and NH4Cl, the fate of retained crystals in the papillar region is studied during a recovery period of one, five or ten days, as model system for human nephrolithiasis. Scanning electron microscopy (SEM) shows, at papillary tips bulging into the calycine space, crystal masses covered either by the epithelium or a thin fibrous veil, or by unidentified mobile cuboidal cells. After CID plus one or five days recovery, small sub-epithelial swellings are seen of large sub-epithelial crystals at or around the papillary tip. …


Dynamic Diseases In Neurology And Psychiatry, John Milton, Deborah Black Mar 1995

Dynamic Diseases In Neurology And Psychiatry, John Milton, Deborah Black

WM Keck Science Faculty Papers

Thirty-two (32) periodic diseases of the nervous system are identified in which symptoms and/or signs recur. In 10/32, the recurrence of a symptom complex is one of the defining features of the illness, whereas in 22/32 oscillatory signs occur in the setting of an ongoing nervous system disorder. We discuss the possibility that these disorders may be dynamic diseases.


Characterization Of A Saccharomyces Cerevisiae Strain Deleted For The Rad27 Gene; A Structural Homolog Of The Rad2 Nucleotide Excision Repair Gene, Michael S. Reagan, Wolfram Siede, Errol C. Friedberg Mar 1995

Characterization Of A Saccharomyces Cerevisiae Strain Deleted For The Rad27 Gene; A Structural Homolog Of The Rad2 Nucleotide Excision Repair Gene, Michael S. Reagan, Wolfram Siede, Errol C. Friedberg

Biology Faculty Publications

No abstract provided.


Dynamical Disease: Identification, Temporal Aspects And Treatment Strategies For Human Illness, Jacques Bélair, Leon Glass, Uwe An Der Heiden, John Milton Mar 1995

Dynamical Disease: Identification, Temporal Aspects And Treatment Strategies For Human Illness, Jacques Bélair, Leon Glass, Uwe An Der Heiden, John Milton

WM Keck Science Faculty Papers

Dynamical diseases are characterized by sudden changes in the qualitative dynamics of physiological processes, leading to abnormal dynamics and disease. Thus, there is a natural matching between the mathematical field of nonlinear dynamics and medicine. This paper summarizes advances in the study of dynamical disease with emphasis on a NATO Advanced Research Workshop held in Mont Tremblant, Quebec, Canada in February 1994. We describe the international effort currently underway to identify dynamical diseases and to study these diseases from a perspective of nonlinear dynamics. Linear and nonlinear time series analysis combined with analysis of bifurcations in dynamics are being used …


Draft Report Of The South Coast Estuarine Fishery Working Group, South Coast Estuarine Fishery Workng Group Mar 1995

Draft Report Of The South Coast Estuarine Fishery Working Group, South Coast Estuarine Fishery Workng Group

Fisheries Management Papers

The South Coast Estuarine Working Group was established in 1991 at the request of commercial fishermen by the Minister of the day. This report outlines a draft management plan for the South Coast Estuarine fishery that was made available for public comment.


Enhancer Trap Technique: A Novel Tool For Identification And Developmental Characterization Of Genes Of Drosophila, Amit Singh Mar 1995

Enhancer Trap Technique: A Novel Tool For Identification And Developmental Characterization Of Genes Of Drosophila, Amit Singh

Biology Faculty Publications

The classical technique of mutational screen for identification of genes controlling early development has now approached saturation. A new era in genetic identification and developmental characterization of genes in Drosophila has commenced with the advent of the enhancer trap technique. This technique involves mobilization of a P-lacZ vector to diverse chromosomal locations in the fruit fly genome to bring it under the regulation of developmentally expressed genes or their enhancer elements. The technique offers a strikingly elegant method of gaining entry into fruit fly genes.


Reproductive Structure And Organogenesis In A Cottonwood, Populus Deltoides (Salicaceae), Robert B. Kaul Mar 1995

Reproductive Structure And Organogenesis In A Cottonwood, Populus Deltoides (Salicaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

The organogenesis of inflorescences, flowers, and fruits was followed for two years in a male and a female tree of eastern cottonwood, Populus deltoides. Soon after anthesis, an inflorescence for the next year is initiated as a continuation of the apical meristem in most axillary buds of the extension shoot of the current year. Bract and then floral primordia arise helically, and by the end of summer all floral appendages are evident. Individual perianth parts are evident early in ontogeny but not at anthesis; they are vascularized independently by distal traces of discrete vascular strands that also serve the …


Review Of "Correspondence: Karl Ernst Von Baer [1792-1876] And Anton Dohrn [1840-1909]" By C. Groeben And J. Oppenheimer, Scott F. Gilbert Mar 1995

Review Of "Correspondence: Karl Ernst Von Baer [1792-1876] And Anton Dohrn [1840-1909]" By C. Groeben And J. Oppenheimer, Scott F. Gilbert

Biology Faculty Works

No abstract provided.


Notes On The Microstructure Of The Nautilus Shell, P. R. Mitchell, P. P. Phakey Feb 1995

Notes On The Microstructure Of The Nautilus Shell, P. R. Mitchell, P. P. Phakey

Scanning Microscopy

The shell of the Nautilus was examined using scanning electron microscopy, transmission electron microscopy and polarized light microscopy. The structure consisted of two major layers: a porcellaneous outer layer and a nacreous inner layer. Most of the porcellaneous layer was composed of granular crystals randomly distributed with a substructure suggestive of bundles of acicular crystallites. A separate prismatic sublayer of the porcellaneous material was composed of a more regular arrangement of crystals. The nacre was composed of alternating crystalline lamellae and films of organic material. The lamellae were formed of many polygonal crystal platelets. The growth surface of the nacre …


Zooplankton Community Structure In Lakes Near Mt. St. Helens, Wa, Larry Duane Scharnberg Feb 1995

Zooplankton Community Structure In Lakes Near Mt. St. Helens, Wa, Larry Duane Scharnberg

Dissertations and Theses

Eighteen lakes around Mt. St. Helens (MSH) were sampled for zooplankton from September '92 until September '94. Samples were enumerated and identified to the species level in most cases. Standard deviation and t-tests were performed to determine the precision of enumeration methods and replication of duplicate tows. Palatability indexes based upon predator preferences were developed and coupled with length-frequency analyses as indicators of predation pressure. The weighted means of the summer samples were then subjected to cluster analysis in an attempt to categorize lakes with respect to zooplankton community structure. Lastly, the community compositions and abundances of MSH lakes were …