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Solubility testing of actinides on breathing-zone and area air samples

Description: A solubility testing method for several common actinides has been developed with sufficient sensitivity to allow profiles to be determined from routine breathing zone and area air samples in the workplace. Air samples are covered with a clean filter to form a filter-sample-filter sandwich which is immersed in an extracellular lung serum simulant solution. The sample is moved to a fresh beaker of the lung fluid simulant each day for one week, and then weekly until the end of the 28 day test period. The soak solutions are wet ashed with nitric acid and hydrogen peroxide to destroy the organic components of the lung simulant solution prior to extraction of the nuclides of interest directly into an extractive scintillator for subsequent counting on a Photon-Electron Rejecting Alpha Liquid Scintillation (PERALS{reg_sign}) spectrometer. Solvent extraction methods utilizing the extractive scintillators have been developed for the isotopes of uranium, plutonium, and curium. The procedures normally produce an isotopic recovery greater than 95% and have been used to develop solubility profiles from air samples with 40 pCi or less of U{sub 3}O{sub 8}. Profiles developed for U{sub 3}O{sub 8} samples show good agreement with in vitro and in vivo tests performed by other investigators on samples from the same uranium mills.
Date: February 1, 1996
Creator: Metzger, R.L.; Jessop, B.H. & McDowell, B.L.
Partner: UNT Libraries Government Documents Department

A multilayer approach to fabricate bioactive glass coatings on Ti alloys

Description: Glasses in the system Si-Ca-Na-Mg-P-K-O with thermal expansion coefficients close to that of Ti6Al4V were used to coat the titanium alloy by a simple enameling technique. Firings were done in air at temperatures between 800 and 840 C and times up to 1 minute. Graded compositions were obtained by firing multilayered glass coatings. Hydroxyapatite (HA) particles were mixed with the glass powder and the mixture was placed on the outer surface of the coatings to render them more bioactive. Coatings with excellent adhesion to the substrate and able to form apatite when immersed in a simulated body fluid (SBF) can be fabricated by this methodology.
Date: December 1, 1998
Creator: Gomez-Vega, J. M.; Saiz, E.; Tomsia, A. P.; Marshall, G. W. & Marshall, S. J.
Partner: UNT Libraries Government Documents Department

Method for detecting and diagnosing disease caused by pathological protein aggregation

Description: A method is provided for detecting pathological macromolecules in a patient, comprising obtaining body fluid from the patient, pretreating the body fluid, subjecting the pretreated body fluid to size-exclusion chromatography to create an excluded fluid, and analyzing the excluded fluid to detect macromolecules having a predetermined molecular weight. The method also allows for comparing elution spectra with reference spectra of suspect pathologic proteins.
Date: December 31, 1994
Creator: Stevens, F.J.
Partner: UNT Libraries Government Documents Department

Kinetics of red blood cell aggregation: an example of geometric polymerization

Description: The kinetics of the process by which red blood cells aggregate into long cylindrical, and sometimes branched, structures called rouleaux is studied within the framework of both reversible and irreversible addition and condensation polymerization reactions. However, unlike usual polymer kinetics, here we take into account the geometry of the subunits and the geometry of the growing structure. Geometric factors such as the amount of reactive wall area influence the probability of branching and hence the final shape of the aggregate. The inclusion of loop formation reactions is shown to be crucial in obtaining physically realistic equilibrium solutions of the kinetic equations. 11 references, 3 figures.
Date: April 2, 1984
Creator: Perelson, A.S. & Samsel, R.W.
Partner: UNT Libraries Government Documents Department

Physiopathology of blood platelets: a model system for studies of cell-to-cell interaction. Progress report, November 1, 1979-October 31, 1980

Description: This report covers the studies on basic mechanisms of cellular interactions, utilizing platelets as a model system and, when possible, concentrating on the influence that environmental factors (nutritional, metabolic, cellular, immunologic and others) have on them. The four major sections include: platelet interaction with tumor cells; a model for the study of cell-to-cell interaction; interaction of platelets with vessel walls; and platelet interactions with immune proteins.
Date: January 1, 1980
Partner: UNT Libraries Government Documents Department

[News Clip: Heat danger]

Description: Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date: May 31, 1985, 6:00 p.m.
Creator: KXAS-TV (Television station : Fort Worth, Tex.)
Partner: UNT Libraries Special Collections

Structure of plant bile pigments

Description: Selective peptide cleavage has provided a general procedure for the study of the structure, including stereochemistry, of plant bile pigments. The information derived from the synthesis and spectral analysis of a series of 2,3-dihydrodioxobilins allows the determination of the trans relative stereochemistry for ring A of the ..beta../sub 1/-phycocyanobilin from C-phycocyanin as well as for ring A of phytochrome. A complete structure proof of the five phycoerythrobilins attached to the ..cap alpha.. and ..beta.. subunits of B-phycoerythrin is described. One of these tetrapyrroles is doubly-peptide linked to a single peptide chain through two thioethers at the C-3' and C-18' positions. The four remaining phycoerythrobilins are singly-linked to the protein through thioethers at the C-3' position and all possess the probable stereochemistry C-2(R), C-3(R), C-3'(R), and C-16(R).
Date: December 1, 1983
Creator: Schoenleber, R.W.
Partner: UNT Libraries Government Documents Department

The antibody approach of labeling blood cells

Description: Although the science of blood cell labeling using monoclonal antibodies directed against specific cellular antigens is still in its early stages, considerable progress has recently been accomplished in this area. The monoclonal antibody approach offers the promise of greater selectivity and enhanced convenience since specific cell types can be labeled in vivo, thus eliminating the need for complex and damaging cell separation procedures. This article focuses on these developments with primary emphasis on antibody labeling of platelets and leukocytes. The advantages and the shortcomings of the recently reported techniques are criticality assessed and evaluated.
Date: January 1, 1991
Creator: Srivastava, S.C.
Partner: UNT Libraries Government Documents Department

Resorption Rate Tunable Bioceramic: Si, Zn-Modified Tricalcium Phosphate

Description: This dissertation is organized in an alternate format. Several manuscripts which have already been published or are to be submitted for publication have been included as separate chapters. Chapter 1 is a general introduction which describes the dissertation organization and introduces the human bone and ceramic materials as bone substitute. Chapter 2 is the background and literature review on dissolution behavior of calcium phosphate, and discussion of motivation for this research. Chapter 3 is a manuscript entitled ''Si,Zn-modified tricalcium phosphate: a phase composition and crystal structure study'', which was published in ''Key Engineering Materials'' [1]. Chapter 4 gives more crystal structure details by neutron powder diffraction, which identifies the position for Si and Zn substitution and explains the stabilization mechanism of the structure. A manuscript entitled ''Crystal structure analysis of Si, Zn-modified Tricalcium phosphate by Neutron Powder Diffraction'' will be submitted to Biomaterials [2]. Chapter 5 is a manuscript, entitled ''Dissolution behavior and cytotoxicity test of Si, Zn-modified tricalcium phosphate'', which is to be submitted to Biomaterials [3]. This paper discusses the additives effect on the dissolution behavior of TCP, and cytotoxicity test result is also included. Chapter 6 is the study of hydrolysis process of {alpha}-tricalcium phosphate in the simulated body fluid, and the phase development during drying process is discussed. A manuscript entitled ''Hydrolysis of {alpha}-tricalcium phosphate in simulated body fluid and phase transformation during drying process'' is to be submitted to Biomaterials [4]. Ozan Ugurlu is included as co-authors in these two papers due to his TEM contributions. Appendix A is the general introduction of the materials synthesis, crystal structure and preliminary dissolution result. A manuscript entitled ''Resorption rate tunable bioceramic: Si and Zn-modified tricalcium phosphate'' was published in Ceramic Engineering and Science Proceedings (the 29th International Conference on Advanced Ceramics and Composites - Advances in Bioceramics ...
Date: August 9, 2006
Creator: Wei, Xiang
Partner: UNT Libraries Government Documents Department

Chapter 9: Model Systems for Formation and Dissolution of Calcium Phosphate Minerals

Description: Calcium phosphates are the mineral component of bones and teeth. As such there is great interest in understanding the physical mechanisms that underlie their growth, dissolution, and phase stability. Control is often achieved at the cellular level by the manipulation of solution states and the use of crystal growth modulators such as peptides or other organic molecules. This chapter begins with a discussion of solution speciation in body fluids and relates this to important crystal growth parameters such as the supersaturation, pH, ionic strength and the ratio of calcium to phosphate activities. We then discuss the use of scanning probe microscopy as a tool to measure surface kinetics of mineral surfaces evolving in simplified solutions. The two primary themes that we will touch on are the use of microenvironments that temporally evolve the solution state to control growth and dissolution; and the use of various growth modifiers that interact with the solution species or with mineral surfaces to shift growth away from the lowest energy facetted forms. The study of synthetic minerals in simplified solution lays the foundation for understand mineralization process in more complex environments found in the body.
Date: July 29, 2006
Creator: Orme, C. A. & Giocondi, J. L.
Partner: UNT Libraries Government Documents Department

Role of Alcohol on the Fracture Resistance of Dentin

Description: Healthy dentin, the mineralized tissue that makes up the bulk of the tooth, is naturally hydrated in vivo; however, it is known that various chemical reagents including acetone and ethanol can induce dehydration and thereby affect its properties. Here, we seek to investigate this in light of the effect alcohol can have on the mechanical properties of dentin, specifically by measuring the stiffness, strength and toughness of dentin in simulated body fluid and scotch whisky. Results indicate that chemical dehydration induced by the whisky has a significant beneficial effect on the elastic modulus, strength and fracture toughness of dentin. Although this makes teeth more resistant to fracture, the change in properties is fully reversible upon rehydration. This effect is considered to be associated with increased cross-linking of the collagen molecules from intermolecular hydrogen-bonding where water is replaced with weaker hydrogen-bond forming solvents such as alcohol.
Date: May 1, 2006
Creator: Nalla, Ravi K.; Kinney, John H.; Tomsia, Antoni P. & Ritchie,Robert O.
Partner: UNT Libraries Government Documents Department

Application of NMR Methods to Identify Detection Reagents for Use in the Development of Robust Nanosensors

Description: Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful technique for studying bi-molecular interactions at the atomic scale. Our NMR lab is involved in the identification of small molecules, or ligands that bind to target protein receptors, such as tetanus (TeNT) and botulinum (BoNT) neurotoxins, anthrax proteins and HLA-DR10 receptors on non-Hodgkin's lymphoma cancer cells. Once low affinity binders are identified, they can be linked together to produce multidentate synthetic high affinity ligands (SHALs) that have very high specificity for their target protein receptors. An important nanotechnology application for SHALs is their use in the development of robust chemical sensors or biochips for the detection of pathogen proteins in environmental samples or body fluids. Here, we describe a recently developed NMR competition assay based on transferred nuclear Overhauser effect spectroscopy (trNOESY) that enables the identification of sets of ligands that bind to the same site, or a different site, on the surface of TeNT fragment C (TetC) than a known ''marker'' ligand, doxorubicin. Using this assay, we can identify the optimal pairs of ligands to be linked together for creating detection reagents, as well as estimate the relative binding constants for ligands competing for the same site.
Date: April 29, 2004
Creator: Cosman, M; Krishnan, V V & Balhorn, R
Partner: UNT Libraries Government Documents Department

Functionalized Silicon Membranes for Selective Bio-Organisms Capture

Description: Membranes with various pore size, length, morphology and density have been synthesized out of diverse materials for size exclusion-based separation. An example of application is the sterilization of intravenous lines by exclusion of bacteria and viruses using Polyvinylidene Fluoride membranes with 0.1 {micro}m diameter pores. The need for chemically specific filtration has recently been addressed, but for small molecules only. An important problem remaining to be solved is the selective capture of large bio-organisms for decontamination or analysis of air and liquids such as drinking water and body fluids. To achieve this goal, materials with controlled pore diameter, length and surface chemistry are required. In this letter, we present the first functionalized silicon membranes and demonstrate their ability to selectively capture simulated bio-organisms. These extremely versatile and rigid devices open the door on a new class of materials able to recognize the external fingerprints of bio-organisms such as size and outer membrane proteins for specific capture and detection applications.
Date: January 9, 2003
Creator: Letant, S E; Hart, B R; van Buuren, A W & Terminello, L J
Partner: UNT Libraries Government Documents Department

Quantification of erythroid and granulocytic precursor cells in plateletpheresis residues

Description: Mononuclear cell fractions of human blood and plateletpheresis residues were compared for their content of hemopoietic precursor cells. Erythroid burst-forming units (BFU-E) averaged 560 +- 130 per ml of blood and granulocyte--monocyte colony forming units (CFU-C) averaged 240 +- 90 per ml blood. Estimates based on a blood volume of 7% of body weight indicate that the total blood pools of BFU-E and CFU-C are about 3.5 x 10/sup 6/ and 1.5 x 10/sup 6/ cells respectively. Sequential studies were performed over 3 days following one plateletpheresis in 4 donors. CFU-C and BFU-E approximately doubled between 48 and 72 hours after a plateletpheresis. During this time there was no significant alteration in the percent of null, T or B lymphocytes in blood. Thus, plateletpheresis appears to lead to a mobilization of precursor cells, which results in a transient increase in their concentration in blood. Therefore, pheresis 48 to 72 hours after an initial short-term procedure could harvest much larger numbers of precursor cells. Moreover, such techniques would put blood precursor cell content of plateletpheresis residues within reach of the precursor cell content in the volume of human marrow used for transplantation.
Date: January 1, 1978
Creator: Abboud, C.N.; Brennan, J.K.; Lichtman, M.A. & Nusbacher, J.
Partner: UNT Libraries Government Documents Department

High-temperature industrial heat pump. Management plan

Description: The management plan for the development and demonstration of a high-temperature industrial heat pump for milk drying is presented. Section 2 describes the overall objective, technical approach, and program scope for development and demonstration of a heat pump system for use in an existing milk drying operation. The high temperature industrial heat pump program organization, its relationships to higher-level AiResearch organizations, subcontractor relationships, and personnel responsibilities are discussed in Section 3. The program management and control functions and data management techniques are described in Section 4. The activity for each work breakdown structure is described in Section 5. The program schedule is schematically shown in Section 6 and cost management reports are described in Section 7.
Date: March 12, 1979
Creator: Deckman, G
Partner: UNT Libraries Government Documents Department

Sorting of a murine granulocytic progenitor cell by use of laser light scattering measurements

Description: Multiangle light-scattering measurements provided a useful basis for analysis and separation of bone marrow cell suspensions. Six to eight major subpopulations of cells could be distinguished by simultaneous measurements of forward and 90/sup 0/ light-scattering, which is more than with any other known cell separation method. The observation that CFU-c were found in only one of these subpopulations confirms the conclusions that CFU-c are a homogeneous population of a single cell type.
Date: January 1, 1977
Creator: Visser, J.W.M.; Cram, L.S.; Martin, J.C.; Salzman, G.C. & Price, B.J.
Partner: UNT Libraries Government Documents Department

Kinetics of reversible-sequestration of leukocytes by the isolated perfused rat lung

Description: The kinetics and morphology of sequestration and margination of rat leukocytes were studied using an isolated perfused and ventilated rat lung preparation. Whole rat blood, bone marrow suspension, or leukocyte suspensions, were used to perfuse the isolated rat lung. The lung was also perfused with latex particle suspensions and the passage of particles through the lung capillaries was studied. When a leukocyte suspension was perfused through the lung in the single-pass mode, the rate of sequestration decreased as more cells were perfused. In contrast, latex particles of a size comparable to that of leukocytes were totally stopped by the lung. When the leukocyte suspension was recirculated through the lung, cells were rapidly removed from circulation until a steady state was reached, after which no net removal of cells by the lung occurred. These results indicate that leukocytes are reversibly sequestered from circulation. The sequestered cells marginated and attached to the luminal surface of the endothelium of post-capillary venules and veins. A mathematical model was developed based on the assumption that the attachment and detachment of leukocytes to blood vessel walls follows first-order kinetics. The model correctly predicts the following characteristics of the system: (a) the kinetics of the sequestration of leukocytes by the lung; (b) the existence of a steady state when a suspension of leukocytes is recirculated through the lung; and (c) the independence of the fraction of cells remaining in circulation from the starting concentration for all values of starting concentration. (ERB)
Date: August 1, 1980
Creator: Goliaei, B.
Partner: UNT Libraries Government Documents Department

Application of Snyder's method for estimation of body burden and intake to blood to uranium bioassay data

Description: The problem of estimating internal exposure from the intake of uranium is discussed. Excreta samples are routinely taken from workers at regular intervals during normal operations and/or after an accidental release of radioactive substances to the immediate environment of the worker. Data on the activity excreted per day is analyzed to estimate the intake of uranium into the blood and the body. (ACR)
Date: January 1, 1983
Creator: Bernard, S.R.
Partner: UNT Libraries Government Documents Department

Flow cytometry for health monitoring in space

Description: Monitoring the health of space station or lunar base residents will be necessary to provide knowledge of the physiological status of astronauts. Flow cytometric techniques are uniquely capable of providing cellular, chromosome, hormone level and enzyme level information. The use of dyes provides the basis for fluorescently labeling specific cellular components. Laser induced fluorescence from stained cells is quantitated in a flow cytometer to measure cellular components such as DNA, RNA and protein. One major application of a flow cytometer will be to perform a complete blood count including hematocrit, hemoglobin content, and numbers of platelets, erythrocytes, granulocytes, lymphocytes and monocytes. A newly developed flow cytometry based fluoroimmunoassay will be able to measure levels of serum enzymes and hormones. It will also be possible to quantitate radiation exposure and some forms of chromosome damage with flow cytometric measurements. With relatively simple modifications to existing technology, it will be possible to construct a flight rated cytometer. 11 references, 6 figures, 2 tables.
Date: January 1, 1984
Creator: Jett, J.H.; Martin, J.C.; Saunders, G.C. & Stewart, C.C.
Partner: UNT Libraries Government Documents Department

Flow cytometric measurements of cell surface phenomena

Description: The study of cell surface phenomena by flow cytometry has been pursued by several groups. These studies have produced new insights into a variety of areas of biology. However, the capabilities of flow systems have not been fully exploited. A technique for discriminating between surface and volume fluorescence is proposed along with a method to quantitate cap formation in lymphocytes.
Date: January 1, 1979
Creator: Jett, J.H.
Partner: UNT Libraries Government Documents Department