Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Life Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1231 - 1260 of 1421

Full-Text Articles in Entire DC Network

Ted Hall And The Science Of Biological Microprobe X-Ray Analysis: A Historical Perspective Of Methodology And Biological Dividends, Brij L. Gupta Mar 1991

Ted Hall And The Science Of Biological Microprobe X-Ray Analysis: A Historical Perspective Of Methodology And Biological Dividends, Brij L. Gupta

Scanning Microscopy

This review surveys the emergence of electron probe X-ray microanalysis as a quantitative method for measuring the chemical elements in situ. The extension of the method to the biological sciences under the influence of Ted Hall is reviewed. Some classical experiments by Hall and his colleagues in Cambridge, UK, previously unpublished, are described; as are some of the earliest quantitative results from the cryo-sections obtained in Cambridge and elsewhere. The progress of the methodology is critically evaluated from the earliest starts to the present state of the art. Particular attention has been focused on the application of the method in …


"Introduction" (To Alfred Russel Wallace; An Anthology Of His Shorter Writings), Charles H. Smith Jan 1991

"Introduction" (To Alfred Russel Wallace; An Anthology Of His Shorter Writings), Charles H. Smith

DLPS Faculty Publications

No abstract provided.


Part I - Papers Presented At The 1989 Plant Science Lecture Series Jan 1991

Part I - Papers Presented At The 1989 Plant Science Lecture Series

Journal of the Iowa Academy of Science: JIAS

The first six titles in this issue of the Journal of Iowa Academy of Science are papers presented at the 1989 edition of the Plant Science Lecture Series held annually at Iowa State University. This lecture series focuses each year on some aspect of plant biology, and each series is composed of six to eight seminars related to a theme that is selected to be timely and related to improvement of field, forage, forest and horticultural crops.


The Gulf Of California As A Large Marine Ecosystem, Patricia A. Morrissey Jan 1991

The Gulf Of California As A Large Marine Ecosystem, Patricia A. Morrissey

Marine Affairs Theses and Major Papers

Large marine regions characterized by unique bathymetry, hydrography and productivity, within which marine populations have adapted reproductive, growth, and feeding strategies constitute large marine ecosystems (LME) (Sherman and Alexander, 1986). The Gulf of California a semi-enclosed sea off the western coast of Mexico qualifies as a LME as it presents physical and biological characteristics not found in the adjoining Pacific. This area sustains the largest commercial fishery in the country which is the sardine fishery. the sardine population resident in the Gulf of California has coupled its reproductive and migration strategies to the environment of this region. Fluctuations of the …


State Of The Fisheries Report 1990, Fisheries Department Of Western Australia Dec 1990

State Of The Fisheries Report 1990, Fisheries Department Of Western Australia

Status Reports of the Fisheries and Aquatic Resources

The State of the Fisheries is published annually by the Fisheries Department as part of the statutory reporting process required under the Fisheries Act. This report covers developments and production in the State's fisheries up to the end of December 1990. Full details of the department's operations for this period are published separately in the department's annual reports for the financial years ending June 1990 and 1991. Figures provided in the tables are derived from catch returns completed by fishermen which are processed by the Australian Bureau of Statistics up to June 1990. Other information provided in the text comes …


Proto-Oncogene Regulation By Growth Factors In Bone Cells, Harold Lyndon Merriman Aug 1990

Proto-Oncogene Regulation By Growth Factors In Bone Cells, Harold Lyndon Merriman

Loma Linda University Electronic Theses, Dissertations & Projects

Previous studies have shown that bone cells in culture produce a number of growth factors that are important in bone regulation. Chick and mouse primary calvarial cultures consist of a mixture of cell types that make it difficult to interpret the results from these model systems. In contrast, MC3T3-E1 cells are a clonal mouse osteoblast-like cell line. Since MC3T3-E1 cells consist of a single population of calvarial cells, they make an ideal system in which to study the autocrine effects of bone growth factors.

Based on this work, MC3T3-E1 cells are now known to produce IGF-I, TGF-beta and IGF-II in …


Degradation Of Refractory Organic Pollutants In Tar, Water And Soil Matrices By Ozone Or Hydrogen Peroxide With Ultraviolet Light, Liang-Jiun Uang Jan 1990

Degradation Of Refractory Organic Pollutants In Tar, Water And Soil Matrices By Ozone Or Hydrogen Peroxide With Ultraviolet Light, Liang-Jiun Uang

Theses

The objective of this research is to develop a method to degrade refractory Tar materials, higher molecular weight 3-5 ring Poly Aromatic Hydrocarbons (PAH's) or degrading these highly refractory PAH structures so that they are amenable to further treatment by biological or chemical methods. The process utilized to achieve this is to treat contaminated soils or tar materials with hydrogen peroxide or ozone plus ultraviolet light. Analysis of 27 specific PAH's was done by gas chromatograph (Flame Ionization Detection) for the reactants and products. The contaminated soil showed significantly lower levels of these PAH's after treatment.


The Cladocera Of Lake West Okoboji, Iowa - Revisited, Kenneth L. Lang Jan 1990

The Cladocera Of Lake West Okoboji, Iowa - Revisited, Kenneth L. Lang

Journal of the Iowa Academy of Science: JIAS

Seven stations, established in 1968 to sample Cladocera, were sampled again, using the same methods, in 1988. Seven species, all of them in low abundance, are new records for Lake West Okoboji. In 1988, there was little difference 1) in the ranking of the stations relative to abundance of cladocerans, 2) the distribution and abundance of the species by habitat-type, 3) the seasonality of the predominant species in the specific habitats, 4) the temporal patterns of the number of species and total cladoceran abundance in the specific habitats, compared to 1968. On the average there were more species but lower …


Degradation Of Wheat Streak Mosaic Virus Capsid Protein During Leaf Senescence, Myron K. Brakke, Rose N. Skopp, L. C. Lane Jan 1990

Degradation Of Wheat Streak Mosaic Virus Capsid Protein During Leaf Senescence, Myron K. Brakke, Rose N. Skopp, L. C. Lane

Department of Plant Pathology: Faculty Publications

Wheat streak mosaic virus capsid protein degraded in vivo by proteolysis as leaves senesced. The capsid protein of virus purified from young systemically infected leaves had an apparent size or 45 kDa in 12% sodium dodecyl sulfate-polyacrylamide gels with minor amounts of 43, 42, 33, and 3E kDa proteins. The proportion of smaller proteins increased with the age of the leaf. In some virus preparations only 3 1 kDa capsid protein was detected. In vitro proteolysis of virions with 45 kDa protein produced virions with 31 kDa protein. Virions with 31 kDa capsid protein sedimented slightly more slowly than those …


Can Genetically Engineered Crops Become Weeds?, Kathleen H. Keeler Nov 1989

Can Genetically Engineered Crops Become Weeds?, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

There are significant differences if the distribution of weedy characteristics among weeds, normal plants, and crops. The world’s most serious weeds possess on the average 10 or 11 of these characters, a random collection of British plants have an average seven of the traits, and crop plants only five. For the average crop to become as “weedy” as the average weed, it would need to acquire five weedy traits. Even using the unlikely assumption that those traits are single loci in which a dominant mutation would provide the weedy character, this would require the simultaneous acquisition of five gene substitutions. …


Embryonic Chicken Fibroblast Collagen Binding Proteins: Distribution, Role In Substratum Adhesion, And Relationship To Integrins, Roy C. Ogle, A. Jeannette Potts, Marchall Yacoe, Charles D. Little Oct 1989

Embryonic Chicken Fibroblast Collagen Binding Proteins: Distribution, Role In Substratum Adhesion, And Relationship To Integrins, Roy C. Ogle, A. Jeannette Potts, Marchall Yacoe, Charles D. Little

School of Medical Diagnostics & Translational Sciences Publications

Collagen binding proteins (CBP) are hydrophobic, cell surface polypeptides, isolated by collagen affinity chromatography. Antibodies to CBPs inhibit the attachment of embryonic chicken heart fibroblasts to native type I collagen fibrils in a dose-dependent manner. The CBP antibodies also induce rounding and detachment of cells adherent to a planar substratum. This process of antibody-mediated substratum detachment resulted in a clustering of CBP and cell-associated extracellular matrix at the cell surface, and the rearrangement of filamentous actin. Other functional studies showed that cells grown within a three-dimensional gel of type I collagen cannot be immunostained at the cell surface with CBP …


The Third International Workshop On Multiple Endocrine Neoplasia Type 2 Syndromes, Friedhelm Raue, Charles E. Jackson Sep 1989

The Third International Workshop On Multiple Endocrine Neoplasia Type 2 Syndromes, Friedhelm Raue, Charles E. Jackson

Henry Ford Hospital Medical Journal

No abstract provided.


Quantitative Electron Probe X-Ray Microanalysis In Biology, T. A. Hall Jul 1989

Quantitative Electron Probe X-Ray Microanalysis In Biology, T. A. Hall

Scanning Microscopy

This review summarizes existing formalisms for the quantitative analysis of biological specimens, and considers the analysis of bulk specimens, micro-droplets, homogenates, and thin or ultrathin sections, respectively. For (ultra)thin sections, one may use elemental ratios for semi-quantitative analysis, measure elemental concentrations as mmol/volume using peripheral standards, or as mmol/kg using the continuum method. Often it is physiologically more relevant to know the concentration of ions as mmol/kg water. This can be achieved by analysing the specimen first in the frozen-hydrated state and then again after freeze-drying, or by using a peripheral standard. Attention has to be given to the selection …


Spectroscopic Study Of Decomposition Products Of Gossypol, David Bernard Hankins Jul 1989

Spectroscopic Study Of Decomposition Products Of Gossypol, David Bernard Hankins

Chemistry & Biochemistry Theses & Dissertations

Basic research into reproductive physiology has begun to identify possible new approaches to controlling fertility. Gossypol, a natural polyphenol compound isolated from cottonseed oil, has been shown to be an effective male antifertility agent. The decomposition products of gossypol which are thought to possess more potent antifertility effects than the parent compound gossypol have been studied extensively in more recent research. The purpose of this research is to develop techniques and methods which could be used to identify decomposition products of gossypol. A model decomposition reaction by which a smaller molecule can be isolated in a pure state has been …


Age And Growth Of King Mackerel, Scomberomorus Cavalla, From The Atlantic Coast Of The United States, Mark R. Collins, David J. Schmidt, C. Wayne Waltz, James L. Pinckney Jan 1989

Age And Growth Of King Mackerel, Scomberomorus Cavalla, From The Atlantic Coast Of The United States, Mark R. Collins, David J. Schmidt, C. Wayne Waltz, James L. Pinckney

Faculty Publications

Whole sagittae from 683 and sectioned sagittae from 773 "adult" (age> 0 ; 437-1.310 mm FL), and lapilli from 29 larval (2-7 mm SL) and 69 young-of-the-year (79-320 mm FL) king mackerel, were examined. All fish were from waters off the Atlantic coast of the southeastern United States (Cape Canaveral, Florida to Cape Fear. North Carolina). Back-calculated lengths at ages and von Bertalanffy growth equations were calculated from both whole and sectioned sagittae. Ages determined from sectioned sagittae were significantly greater than ages determined from whole sagittae, and the magnitude of the difference increased with age (from sections). Rings on …


The Quest Of Dr. Ernest F. Bashford For Knowledge About Cancer Etiology In Man And Mouse, Anne J. Krush Jan 1989

The Quest Of Dr. Ernest F. Bashford For Knowledge About Cancer Etiology In Man And Mouse, Anne J. Krush

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Dr. Ernest F. Bashford, an English physician,lived from 1873 to 1923. For many years before his untimely death, he was an officer for the Imperial Cancer Research Fund. From articles in the British Medical Journal and other publications, Bashford prepared a volume of reprints (1903-1909) concerning problems, growth, and heredity of cancer, and experiments with breast cancer in mice. Cancer had been studied histologically and clinically, with only speculation as to its origin, nature, and cause in man. He suggested cooperative studies by investigators in many different fields. Concerned with why the growth of cancer seemed limitless, and with problems …


Immune, Growth And Carcass Responses Of Ram Lambs To Active Immunization Against Desulfated Cholecystokinin (Cck-8), W. E. Trout, J. C. Pekas, B. D. Schanbacher Jan 1989

Immune, Growth And Carcass Responses Of Ram Lambs To Active Immunization Against Desulfated Cholecystokinin (Cck-8), W. E. Trout, J. C. Pekas, B. D. Schanbacher

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

This study explored feed intake and carcass responses to active immunization against desulfated cholecystokinin-octapeptide (CCK-8) in ram lambs. Antibody titers 8 wk following primary immunization and booster immunizations given at 4 and 6 wk averaged greater than 1:1,000. Titers increased to greater than 1:10,000 by 16 wk following a final booster immunization at 11 wk. The antibodies developed against desulfated CCK-8 exhibited 29% and 13% cross-reactivities for sulfated CCK-8 and gastrin-17, respectively. Immunization against desulfated CCK-8 had no effect on feed intake, ADG, carcass weight or carcass quality grade. Backfat thickness and carcass yield grade were reduced (P < .05) by immunization. Organ weights at slaughter, including those of the pancreas and small intestines, were not affected by CCK-8 immunization, with the exception of the lungs, which were 16% lighter (P < .01) in immunized lambs. In conclusion, active immunization against desulfated CCK-8 resulted in development of high antibody titers against desulfated and sulfated CCK-8. Immunization against CCK-8 decreased fat content of the carcass but failed to affect feed intake, carcass weight or ADG.


Metabolic Bone Disease In Children, Michael P. Whyte Sep 1988

Metabolic Bone Disease In Children, Michael P. Whyte

Henry Ford Hospital Medical Journal

No abstract provided.


Department Of Entomology Newsletter - No. 5, Part 1, 1988, George R. Manglitz Sep 1988

Department Of Entomology Newsletter - No. 5, Part 1, 1988, George R. Manglitz

Hexapod Herald and Other Entomology Department Newsletters

When the last Newsletter was published in 1976 (No.4), it was assumed that it would be followed by another In 4 or 5 years. And indeed, considerable effort has been expended on the production of No.5. However, for various very good reasons No.5, although close to publication several times, aborted several times. Now largely because this is the centennial year of our Department, we feel that we can wait no longer. Because of that fact, the format of this Newsletter will be slightly different from those in the past. We have the "news" that you furnished about yourselves 5 or …


The Ultrastructure Of Dentine From Rat Incisors Following Exposure To Sodium Fluoride And Potassium Pyroantimonate Staining, J. Appleton Jul 1988

The Ultrastructure Of Dentine From Rat Incisors Following Exposure To Sodium Fluoride And Potassium Pyroantimonate Staining, J. Appleton

Scanning Microscopy

Weanling rats were given a single intra-peritoneal injection of sodium fluoride and control animals normal saline for four consecutive days. The fluoride produced a consistent response in the mineralizing dentine of the incisors in which a hypermineralized band was succeeded by a hypomineralized band. Potassium pyroantimonate staining for calcium ions showed that following injection of fluoride, in contrast to the controls, there were large amounts of calcium pyroantimonate in the pre-dentine and throughout the odontoblasts. This suggests that fluoride temporarily affects the membrane enzyme systems which maintain calcium concentration gradients between the odontoblasts and the matrix. The resultant influx of …


Proton Microprobe And Particle Induced X-Ray Emission (Pixe) Analysis For Studies Of Pathological Brain Tissue, K. G. Malmqvist, A. Brun, K. Inamura, E. Martins, L. G. Salford, B. K. Siesjö, U. A. S. Tapper, K. Themner Apr 1988

Proton Microprobe And Particle Induced X-Ray Emission (Pixe) Analysis For Studies Of Pathological Brain Tissue, K. G. Malmqvist, A. Brun, K. Inamura, E. Martins, L. G. Salford, B. K. Siesjö, U. A. S. Tapper, K. Themner

Scanning Microscopy

Particle Indiced X-ray Emission and proton microprobe analyses have been applied for the investigation of regional elemental distributions in connection with various pathological states in the brain. Malignant brain tumours and adjacent histologically intact tissue removed during surgery were analysed with PIXE. Systematic elemental variations, e.g., for calcium and selenium, were observed in the tumour front. The proton microprobe was applied to study the Ca and K concentrations in various cell strata in hippocampus following transient ischaemia in rat brain. Significant increases in the Ca level occurred in selectively vulnerable cells within 48 h after the ischaemia.


Queen Pheromone Production And Its Physiological Correlates In Fire Ant Queens (Hymenoptera: Formicidae) Treated With Fenoxycarb, Martin S. Obin, B. Michael Glancey, W. A. Banks, Robert K. Vander Meer Jan 1988

Queen Pheromone Production And Its Physiological Correlates In Fire Ant Queens (Hymenoptera: Formicidae) Treated With Fenoxycarb, Martin S. Obin, B. Michael Glancey, W. A. Banks, Robert K. Vander Meer

Entomology Papers from Other Sources

Biological assays were used to evaluate the effect of the insect growth regulator fenoxycarb (ethyl (2-p-phenoxyphenoxy) ethyl carbamate) on production of queen-derived dealation inhibitory pheromone and the queen recognition pheromone of Solenopsis invicta Buren. Treated virgin and mated queens weighed less and were less capable of inhibiting dealation by female alates than were nontreated controls. Virgin queens that gained weight during the experimental trials produced more dealation inhibitory pheromone and more queen recognition pheromone than virgin queens that lost weight. Treated virgin queens with fenoxycarb-induced ovary dysfunction inhibited de alation in proportionally fewer alates than treated virgin queens of similar …


Quantitative Analysis Of Temperature., Moisture., And Diet Factors Affecting Insect Development, David W. Hagstrum, George A. Milliken Jan 1988

Quantitative Analysis Of Temperature., Moisture., And Diet Factors Affecting Insect Development, David W. Hagstrum, George A. Milliken

Entomology Papers from Other Sources

Extensive published data on the developmental times of nine species of stored-product Coleoptera in relation to temperature, moisture, and diet were described by regression equations. At most temperatures, the order of relative influence of these factors on development was temperature > moisture > diet. However, moisture and diet influenced larval development more than temperature near the optimal temperature for development of each species. Egg, larval, and pupal stage durations at 27°C averaged 15, 66, and 19% of the total developmental time, respectively, at moistures above 12%, and 12, 72, and 15% of total developmental time at moistures below 12%. Similar percentages were …


Cellular Politics: Ernest Everett Just, Richard B. Goldschmidt, And The Attempt To Reconcile Embryology And Genetics, Scott F. Gilbert Jan 1988

Cellular Politics: Ernest Everett Just, Richard B. Goldschmidt, And The Attempt To Reconcile Embryology And Genetics, Scott F. Gilbert

Biology Faculty Works

No abstract provided.


Adaptability Of Scanning Electron Microscopy To Studies Of Pollen Morphology, John J. Skvarla, John R. Rowley, William F. Chissoe Jan 1988

Adaptability Of Scanning Electron Microscopy To Studies Of Pollen Morphology, John J. Skvarla, John R. Rowley, William F. Chissoe

Aliso: A Journal of Systematic and Floristic Botany

We have explored methods to achieve excellent results in study of the pollen grain wall by using only one electron microscope, the scanning electron microscope (SEM). While the secondary electron imaging mode, the most common in use, has great value in characterizing the exine surface it is possible to obtain a more comprehensive representation of pollen grain walls by expanding the capability of the secondary mode and making use of backscatter and transmission imaging detectors. In this way information is obtained about internal exine features that are likely to be more stable phylogenetically than the generally late-to-form surface structure. We …


The Hiv Seropositive State And Progression To Aids: An Overview Of Factors Promoting Progression, Paul H. Black, Elinor M. Levy Jan 1988

The Hiv Seropositive State And Progression To Aids: An Overview Of Factors Promoting Progression, Paul H. Black, Elinor M. Levy

New England Journal of Public Policy

We have considered factors that predispose to infection by the human immunodeficiency virus as well as the clinical consequences of infection. We have also reviewed what is known about the virological status of the asymptomatic carrier, particularly the female, and the fact that pregnancy may be a cofactor for progression of HIV disease in seropositive women. Additionally, we have discussed several other cofactors that may promote the progression of HIV infection. These include intercurrent infection, excessive use of recreational drugs and alcohol, malnutrition, and stress. With respect to stress, we have reviewed evidence indicating that certain personality factors, by buffering …


Variation In Chromosome Length Among Five Biotypes Of The Greenbug (Homoptera: Aphididae), Z. B. Mayo, K. J. Starks, D. J. Banks, R. A. Veal Jan 1988

Variation In Chromosome Length Among Five Biotypes Of The Greenbug (Homoptera: Aphididae), Z. B. Mayo, K. J. Starks, D. J. Banks, R. A. Veal

Department of Entomology: Faculty Publications

Chromosome-length measurements from five greenbug, Schizaphis graminum (Rondani), biotypes (B, C, E, F, and Maryland) were compared by discriminant analyses procedures. There were highly significant (P = 0.0001) differences in total lengths of chromosome sets among biotypes. In individual paired comparisons, where each biotype was compared with only one other biotype at a time, chromosome measurements correctly classified aphids to their respective biotype in 45-85% of the cases. Degree of correct classification was dependent on the two biotypes being compared and the discriminant function used in the analysis. Results indicate that there are two groups of biotypes that can be …


Effects Of A Dispersed And Undispersed Crude Oil On Mangroves, Seagrasses And Corals, T. G. Ballou, Richard E. Dodge, S. C. Hess, A. H. Knap, Thomas D. Sleeter Oct 1987

Effects Of A Dispersed And Undispersed Crude Oil On Mangroves, Seagrasses And Corals, T. G. Ballou, Richard E. Dodge, S. C. Hess, A. H. Knap, Thomas D. Sleeter

Marine & Environmental Sciences Faculty Reports

The primary objective of this study was to evaluate the application of dispersant to spilled oil as a means of reducing adverse environmental effects of oil spills in nearshore, tropical waters. The results of numerous laboratory and field studies have suggested that dispersants may play a useful role in reducing adverse impacts on sensitive and valued environments such as mangroves, seagrasses, and corals. However, the use of dispersants has not been allowed thus far in most situations because of a lack of direct experimental data on the various effects of dispersants and the environmental trade-offs presumed to occur as a …


Electron Energy Loss Spectroscopic Imaging In Biology, G. T. Simon, Y. M. Heng Sep 1987

Electron Energy Loss Spectroscopic Imaging In Biology, G. T. Simon, Y. M. Heng

Scanning Microscopy

One of the goals in biology is to relate the ultrastructure with the movement of elements to under stand better physiological and pathophysiological mechanisms. Electron energy loss spectroscopy (EELS) imaging, which was developed in the last decade, appears to be an ideal technique to make such correlation.

EELS takes advantage of the energy distribution of transmitted electrons which interacted with the specimen. All these electrons are collected and can be displayed as an energy loss spectrum for analytical purposes. Images can be produced from selected regions from the energy distribution allowing the mapping of specific elements. The main advantage of …


The Second International Workshop On Multiple Endocrine Neoplasia Type 2 Syndromes, Bruce A. J. Ponder, Charles E. Jackson Jun 1987

The Second International Workshop On Multiple Endocrine Neoplasia Type 2 Syndromes, Bruce A. J. Ponder, Charles E. Jackson

Henry Ford Hospital Medical Journal

No abstract provided.