Digital Commons Network^™

From Scattering And Recoiling Spectrometry To Scattering And Recoiling Imaging, M. M. Sung, V. Bykov, A. Al-Bayati, C. Kim, S. S. Todorov, J. W. Rabalais

Scanning Microscopy

A new ion scattering technique, called scattering and recoiling imaging spectrometry (SARIS), is being developed. The SARIS technique uses a large, position sensitive microchannel plate (MCP) and time-of-flight methods to capture images of scattered and recoiled particles from a pulsed ke V ion beam. These images combine the advantage of atomic scale microscopy and spatial averaging simultaneously since they are created from a macroscopic surface area but they are directly related to the atomic arrangement of the surface. This paper de-scribes the basis of the SARIS technique, the instrument which is under development, and the scattering and recoiling …

Crystallographic Evidence For Dimerization Of Unliganded Tumor Necrosis Factor Receptor, James H. Naismith, Tracey Q. Devine, Barbara J. Brandhuber, Stephen R. Sprang

Biological Sciences Faculty Publications

Activation of the cell surface receptors for tumor necrosis factor (TNF) is effected by the aggregation of cytoplasmic domains that occurs when the extracellular domains of two or three receptors bind to trimeric TNFα or TNFβ. The structure of the type I TNF receptor extracellular domain (sTNF- R1), crystallized in the absence of TNF, has now been determined at 2.25-Å resolution. The receptor itself is an elongated molecule comprising four disulfide-rich domains in a nearly linear array. Contrary to expectations, the unliganded domains are found to associate into dimers of two distinct types, in which monomers are related by local …

Management Options (Discussion Paper) For The Shark Bay Snapper Limited Entry Fishery, Shark Bay Snapper Limited Entry Fishery Working Group, Doug Bathgate

Fisheries Management Papers

At the Annual Management Meeting of the Shark Bay Snapper Limited Entry Fishery held on 22 July 1994 industry put forward a proposal that supplementary and non-transferable quota that was "lost" to the fishery when a licence holding non-transferable quota was transferred should be retained by the Fisheries Department and leased back to licence holders on an annual basis. As a result of this proposal and the fact that the management arrangements for the fishery are extremely complex and in need of simplification, the Minster for Fisheries approved the establishment of a Working Group to examine the lease-back proposal and …

Management Of The Northern Demersal Scalefish Fishery, Jane Fowler

Fisheries Management Papers

In mid 1994, the Fisheries Department of Western Australia announced that it would prepare a discussion paper setting out options for future management of the demersal scalefish fishery off the Kimberley coast. This paper, which was to be the start of a wider consultative process, was also to include options for possible further development of the trap and line fisheries. This paper is only the first step in a process for developing formal long term management arrangements under the new fisheries legislation, the Fish Resources Management Act 1994. Its aim is to provide some background and to present some management …

Report On Future Management Options For The South West Trawl Limited Entry Fishery, South West Trawl Limited Entry Fishery Working Group

Fisheries Management Papers

As a result of community concern regarding trawling, the current management rules for the South West Trawl Limited Entry Fishery were finalised in February 1989 and the final plan was gazetted in October of that year. However, there was public disquiet about this trawling, and as a result of this disquiet, a research program was initiated by the Fisheries Department with funding received from both the Commonwealth and State Governments. The scientific report, "The impact of trawling for saucer scallops and western king prawns on the benthic communities in coastal waters off south-western Australia" by L J B Laurenson, P …

Effects Of Reproductive Mode On Demography And Life History In Arabis Fecunda (Brassicaceae), Peter Lesica, J. Stephen Shelly

Biological Sciences Faculty Publications

Life history theory predicts that trade-offs between growth and reproduction should be dictated by a population's mortality schedule. We tested this prediction with Arabis fecunda, a short-lived perennial that occurs in many different habitats in southwest Montana. Individuals produce either or both axillary or terminal inflorescences. Axillary-flowering plants are usually iteroparous and have smaller reproductive bouts, while terminal-flowering plants have larger reproductive bouts, and tend to be semelparous. We recorded size and fecundity of A. fecunda individuals from 1989 to 1993 in three different habitats. There was great variation in demographic and life history traits among the populations. A …

Static Forces And Moments Generated In The Insect Leg: Comparison Of A Three-Dimensional Musculo-Skeletal Computer Model With Experimental Measurements, Robert J. Full, Anna N. Ahn

All HMC Faculty Publications and Research

As a first step towards the integration of information on neural control, biomechanics and isolated muscle function, we constructed a three-dimensional musculo-skeletal model of the hind leg of the death-head cockroach Blaberus discoidalis. We tested the model by measuring the maximum force generated in vivo by the hind leg of the cockroach, the coxa-femur joint angle and the position of this leg during a behavior, wedging, that was likely to require maximum torque or moment production. The product of the maximum force of the leg and its moment arm yielded a measured coxa-femur joint moment for wedging behavior. The …

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 …

Vitamin E Deficiency As A Model Of Precocious Brain Aging: Assessment By X-Ray Microanalysis And Morphometry, Carlo Bertoni-Freddari, Patrizia Fattoretti, Ugo Caselli, Roberta Paoloni, William Meier-Ruge

Scanning Microscopy

Vitamin E (α-tocopherol) is a known biological antioxidant able to quench the lipid peroxidation chain and to protect the cellular structures (e.g., plasma membranes) from the attack of free radicals which are reported to play a primary role in aging. To assess whether the absence of α-tocopherol from the diet of young laboratory animals may be considered a reliable model of precocious brain aging, intracellular ionic content of brain cortex pyramidal cells, ultrastructural features of synaptic contact zones, synaptic mitochondria and perykarial mitochondria positive to the succlillc dehydrogenase (SDH) histochemical reaction with copper ferrocyanide have been investigated by X-ray microanalysis …

A High-Bandwidth Frequency-Domain Photon Migration Instrument For Clinical Use, Steen J. Madsen, Eric R. Anderson, Richard C. Haskell, Bruce J. Tromberg

All HMC Faculty Publications and Research

We have developed a high-bandwidth frequency-domain photon migration (FDPM) instrument which is capable of noninvasively determining the optical properties of biological tissues in near-real-time. This portable, inexpensive, diode-based instrument is unique in the sense that we employ direct diode laser modulation and avalanche photodiode detection. Diffusion models were used to extract the optical properties (absorption and transport scattering coefficients)of tissue-simulating solutions.from the 300 kHz to I GHz photon density wave data.

High Resolution Electron Microscopy Of The Interface Between Dental Calculus And Denture Resin, Yoshihiko Hayashi

Scanning Microscopy

Dental calculus may grow on the denture surface. In order to demonstrate the mechanism of deposition, the interface between calculus and denture resin was investigated using a high resolution electron microscope. Ultrathin sections were also used for electron diffraction of selected areas to reveal any mineral phase.

The mineral layers without mineralized bacteria adjacent to the denture surface revealed a marked variation in thickness and crystal shape. Three types of crystal shape were observed at the junction: needle-like, rod-like and plate-like crystals. High resolution electron microscopy (HREM) showed that both rod-like and plate-like crystals were an aggregation of fine crystallites. …

The Influence Of 5-Fluorouracil On The Endothelium In Small Arteries. An Electron Microscopic Study In Rabbits, M. Cwikiel, B. Zhang, J. Eskilsson, J. B. Wieslander, M. Albertsson

Scanning Microscopy

5-Fluorouracil (5-FU) is a widely used antineoplastic agent. 5-FU induced cardiotoxicity is a still relatively unknown side-effect of this drug. This phenomenon could be due to a direct cytotoxic effect on the endothelial cells. We tested this hypothesis in an experimental study in rabbits, by scanning or transmission electron microscopic evaluation of endothelium in small arteries (the central artery of the ear) after in vivo treatment with 5-FU. Both local and systemic effects of 5-FU on endothelium were studied 15, 30, 60 and 120 minutes after intra-arterial or intraperitoneal treatment. Perfusion fixation at physiological pressure and temperature was used in …

Cathodoluminescence Contrast Of Localized Defects Part I. Numerical Model For Simulation, K. L. Pey, D. S. H. Chan, J. C. H. Phang

Scanning Microscopy

A three-dimensional model has been developed for cathodoluminescence contrast of localized defects in semiconductors. The numerical model incorporates electron-solid interaction effects, charge transport phenomena and optical losses. Electron-solid interaction is modelled by a Monte Carlo method. Three-dimensional continuity equation and derivative boundary conditions are discretized by a central-difference quotients scheme. Localized defects are represented by regions of enhanced non-radiative recombination. The discretized linear difference equations of the boundary value problem are solved by the successive-over-relaxation method. A method for avoiding the divergence problem during the successive-over-relaxation calculation is illustrated. The solutions of the model are compared with the analytical results …

Cathodoluminescence Contrast Of Localized Defects Part Ii. Defect Investigation, K. L. Pey, J. C. H. Phang, D. S. H. Chan

Scanning Microscopy

Cathodoluminescence contrast from defects with different geometrical and electronic properties have been studied using the numerical model developed in Part I. The contrast of a localized subsurface defect exhibits a maxima at a specific beam energy E_max which corresponds to the depth of the defect. The contrast of a dis-location which intersects the top surface perpendicularly is a decreasing function of beam energy. The differences in the image profiles of the two different kinds of defects allow the two types of imperfections to be distinguished. In addition, the resolution of a subsurface defect at beam energies lower than E …

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 …

Apoptosis Induced By Microtubule Disrupting Drugs In Normal Murine Thymocytes In Vitro, Vladimir Bumbaširević, Andjelija Škaro-Milić, Aleksandar Mirčić, Bogdan Djuričić

Scanning Microscopy

Disruption of cytoplasmic and spindle microtubules by colchicine or nocodazole increases mitotic index, but it also enhances apoptosis in isolated mouse thymocytes; the apoptotic index exceeds 20% after 4 hours of incubation with either drug (5% in controls). Apoptosis was confirmed by DNA fragmentation, and was blocked by calcium chelators and inhibitors of protein synthesis. The apoptotic effect of microtubule disrupting drugs (MOD) was directed to interphase thymocytes and was independent on MOD action on mitotic cells. However, cell death of mitotically arrested cells showed ultrastructural changes similar in many aspects to apoptosis.

The Criminological Significance Of The Comparative Analysis Of Serum Albumins Using Electrophoresis And Immuno Gel Diffusion, Rhonda E. Ross-Ries

Whittier Scholars Program

Scientists and forensic experts are making use of macromolecules and their separation. Proteins are unique macromolecules produced by individuals and have provided key evolutionary genetic relationships. Two of the most common techniques used to separate proteins for analyzation electrophoresis and the Ouchterlony technique. The purpose of this comparative analysis project was to broaden the researcher’s laboratory skills to compare the two techniques in terms of efficiency,, cost efficiency, accuracy of results, and interpretation of results. Albumins were chosen for analysis because these proteins are known to be important to biology and are in great concentration in blood plasma.

Optical Microscopy And Atomic Force Microscopy Imaging Of 2,4,6-Trinitrotoluene Droplets And Clusters On Mica, D. O. Henderson, M. A. George, A. Burger, R. Mu, Zhiyu Hu, G. C. Huston

Scanning Microscopy

Optical and atomic force microscopy (AFM) were used to image 2,4,6-trinitrotoluene (TNT) on a cleaved mica (001) surface. The vapor deposition of TNT resulted in ellipsoidal drop formation on the mica surface. The growth rate of the drop diameter was found to be linear with vapor dosing time while the drop density followed a 1/r² dependence, where r is the length of the major axis of the ellipsoid, for increasing dosing times. TNT platelets surrounded by a region depleted of drops were observed after 8 hours of dosing. The depleted region is attributed to a 10% shrinkage for liquid-solid …

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

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 …

3 Genes Of The Map Kinase Cascade, Mek-2, Mpk-1/Sur-1 And Let-60 Ras, Are Required For Meiotic Cell-Cycle Progression In Caenorhabditis-Elegans, Diane L. Church, Kun Liang Guan, Eric J. Lambie

Dartmouth Scholarship

In the germline of Caenorhabditis elegans hermaphrodites, meiotic cell cycle progression occurs in spatially restricted regions. Immediately after leaving the distal mitotic region, germ cells enter meiosis and thereafter remain in the pachytene stage of first meiotic prophase for an extended period. At the dorsoventral gonadal flexure, germ cells exit pachytene and subsequently become arrested in diakinesis. We have found that exit from pachytene is dependent on the function of three members of the MAP kinase signaling cascade. One of these genes, mek-2, is a newly identified C. elegans MEK (MAP kinase kinase). The other two genes, mpk-1/sur-1 (MAP kinase) …

The Effect Of Arf-Excimer Laser Irradiation Of The Human Enamel Surface On The Bond Strength Of Orthodontic Appliances, U. Stratmann, K. Schaarschmidt, M. Schürenberg, U. Ehmer

Scanning Microscopy

This study investigated enamel laser conditioning as an alternative to acid etching in bracket therapy. In preliminary experiments optimal laser parameters for achieving a bond strength of 6-10 N/mm² were defined. Enamel surface morphology was assessed and the ablation depth was measured on serial enamel sections. Thirty human molars were exposed to 193 nm ArF-excimer laser radiation (energy density: 260 mJ/cm²) by single pulse application of 23 nanoseconds. Thirty molars were etched with phosphoric acid (37%) for 60 seconds. The brackets from the treated molars and 30 untreated molars were debonded vertically for tensile bond strength measurement. …

Synthesis Of Nitrosyl Metallpoprphyrins, Thomas M. Braxton Jr.

McCabe Thesis Collection

Nitric oxide, NO, is a molecule with great versatility and importance. Made up of only a single atom of nitrogen and a single atom of oxygen, nitric oxide is perhaps one of the smallest paramagnetic molecules found in nature. The functions of NO in the body are not all known, but this molecule definitely plays a variety of roles. It is involved in the regulation of blood pressure, and it sometimes acts as a messenger for cells as well as a killer of them. It also is important in the defense of the body against foreign invaders. The significance of …

The Nutritional Knowledge, Food Choices, And Exercise Habits Of Students At Langston University, Preston Solomon

McCabe Thesis Collection

The nutritional knowledge, food choice, and exercise habits of an individual determine his or her overall health and life expectancy. Information on these topics enables nutrition educators to develop strategies to improve knowledge and to tailor educational efforts which affect a large number of persons. Poor health in America today is an ever present reality. Heart disease, cancer, diabetes mellitus, cerebrovascular diseases, renal diseases, and pulmonary diseases are causes of death related in part to lack of nutritional knowledge and poor eating and exercise habits. A few of these diseases are chronic in nature and are the most deadly.

The …

Preliminary Keys To Carex (Cyperaceae) In New York State, Gordon Tucker

Faculty Research & Creative Activity

No abstract provided.

Preliminary Keys To Carex (Cyperaceae) In New York State, Gordon C. Tucker

Faculty Research & Creative Activity

No abstract provided.

Preliminary Keys To Carex (Cyperaceae) In New York State, Gordon C. Tucker

Faculty Research & Creative Activity

No abstract provided.

Circadian Rhythm Of Brain Gaba Levels In The Cockroach, Leucophaea Maderae, Juli Martin Mccay, Jeanette Marie Gibson

Mahurin Honors College Capstone Experience/Thesis Projects

Brain levels of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) were determined at three-hour intervals in roaches acclimated to a 12-hour lightl12-hour dark cycle (light onset 0600 h) at 25 ± 2° C using high performance liquid chromatography coupled with fluorometnc detection GABA levels were found to be highest at noon and lowest at 1800 h. A difference between the high and low levels at these two times remained during the second day under constant dark conditions, indicating that GABA levels do indeed vary on a circadian basis. Brain GABA levels were highest at a time of day that corresponded with …

The Bag And Size Limit Review: New Regulations And Summary Of Submissions, F. B. Prokop, J M. Collins

Fisheries Management Papers

Since the new bag and size limits were introduced in December 1991, there have been many suggestions for refinement and improvement of these regulations. This paper includes the summary of submissions to Fisheries Management Paper No 52 - Review of Bag and Size Limit Proposals for Western Australian Recreational Fishers and details new regulations which will come into force on 1 July 1995.

The Best Available Information - Its Implications For Recreational Fisheries Management, F. B. Prokop

Fisheries Management Papers

Workshop at Second National Fisheries Managers Conference, Bribie Island, Queensland, October 18, 1994. Recreational fisheries management is one of the growth areas in Australian fisheries. The Australian Society for Fish Biology Workshop topic for its 1994 Conference was Recreational Fishing - What's the Catch. It was acknowledged at the ASFB conference that there were generally poor levels of information and for the lower value commercial and recreational fisheries there may be no way to gather definitive research data for the foreseeable future. However, in even the high profile fisheries, public perceptions, attitudes, and political will do not allow for the …