Research into chemical separation techniques for production of Bi-213 via irradiation of Ra-226 [abstract]

Abstract only availableBismuth 213 is an alpha radioimmunotherapeutic agent used in cancer treatment. Neutron bombardment of radium 226 is being investigated as an alternative method of producing Bi-213. For this project, a literature search of existing chemical separation steps for the production of Bis-213 for radioimmunotherapy was performed in order to optimize the combination of irradiation schemes with chemical separation steps. For the first step, the separation of actinium and radium from thorium 229 and recovery of radium for further irradiation, several successful methods were described in the literature. Organic cation exchange columns such as AG50W-X8 have traditionally been used to perform this step, but these suffer high radiolysis, which newer methods have tried to address. Some of these are an extraction chromatography method using a UTEVA column followed by a RE-resin column on a silica gel support, an inorganic titanium phosphate ion exchanger, and sublimation of the anhydrous chlorides of Th-229 and its daughter isotopes performed in a quartz tube, featuring complete separation of the elements while radium is retained at the bottom of the tube and available for further irradiation in one step. For the second part of the process, the elution of Bis-213 from an Ac-225 generator, quite a few successful techniques are described in the literature. Some of the better ones found are a multicolumn selectivity inversion generator, a renewable column, tandem column extraction chromatography, a PNNL automated generator, a MSKCC generator, an inorganic hydrated zirconium cation exchanger, and silica based resins, as well as the more traditional organic cation and anion exchange columns. A method using alpha recoil of Bis-213 from Ac-225 incorporated into a sealed isotope generator has the benefit of resulting in no radioactive, chemical, or mixed wastes, in contrast to chemical separation methods. In conclusion, several promising separation techniques were found in the literature

Non‐linear mixing effects on mass‐47 CO2 clumped isotope thermometry: Patterns and implications

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110849/1/rcm7175.pd

Design of an Automatic System for the University of Missouri Research Reactor's (MURR) Small Diameter Pneumatic-Tube (P-Tube) System [abstract]

Abstract only availableThe nuclear research facility at the University of Missouri-Columbia (MURR) has proposed a redesign of the process for irradiating the samples with INAA (Instrumental Neutron Activation Analysis) in order to increase efficiency (sample throughput), to lower the costs of experiments and to minimized dosage radiation exposure for workers. INAA was discovered in 1936 when Hevesy and Levi found that samples containing certain unusual earth elements became highly radioactive after been in contact to a source of neutrons. From this observation, they rapidly acknowledged the potential of employing nuclear neutron bombardment of samples followed by measurement of the induced radioactivity to smooth the progress of both quantitative and qualitative detection of the elements present in the samples. This new design includes a circular sample storage tray, a pneumatic gripper (for both sealing and for sending and returning of the sample from the reactor), a rotary table motor and two slider motors--one for the gripper and one for moving the sample closer to the counter machine. After the new design was conceived, the Research Reactor needed an automatic control system for the motors that were going to move the samples so they could be sent to the reactor and to the radiation detection room. My responsibility was to design the control system for the operation of the motors. The design (programming) software that I chose to use was LABVIEW programmi EMAILED 7/26/07!

Paleoelevation estimates for the northern and central proto–Basin and Range from carbonate clumped isotope thermometry

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99057/1/tect20016.pd

Analyzing the effects of lactose on calcium absorption in premature infants using HR-ICP-Mass Spectrometry

Abstract only availableWith advances in neonatal care, premature infants are surviving at increasing rates. During the third trimester of pregnancy, the bone mineral content of infants rapidly increases. It is therefore becoming essential to accurately mimic the womb environment to maintain growth and sustain the health of premature infants as if they were in utero. Regulating calcium absorption in premature infants is crucial primarily for bone formation, as 99% of the calcium in the human body is found in the bones and the teeth. The effect of lactose containing formulas on calcium absorption in premature infants has not been well established. Concerns have been noted in the scientific community regarding lactose intolerance especially in premature infants, as lactase, the enzyme responsible for lactose digestion, is most readily detectible during the third trimester of pregnancy. In this study, in conjunction with Dr. Laura Hillman of the University of Missouri Hospital, each infant was fed lactose and maltose formulas during different weeks using a dual tracer method in which two calcium isotopes were administered, 44Ca orally and 46Ca intravenously. Urine samples were collected after 24 hours. Analysis related natural abundances of calcium isotopes to the measured values in the urine. Polyatomic ion interferences were differentiated from the calcium peaks by analyzing the samples at a resolution of 4000. Mathematical corrections for interferences caused by titanium and doubly charged strontium were determined by measuring the specific isotopes 47Ti and 87Sr++ and using known natural abundances of the interfering isotopes to correct each calcium count rate. Mathematical calculations relate the enriched isotope ratio measurements of 44Ca and 46Ca to calcium absorption. Analysis regarding the effect of lactose on calcium absorption is ongoing. Our data precision on the ICP-MS was acceptable with percent relative standard deviations (%RSD) for external precision over the course of a week at 1.4, 2.2, 0.71, and 1.4 for isotope ratios 42Ca: 43Ca, 42Ca: 44Ca, 42Ca: 46Ca, and 42Ca: 48Ca respectively. Daily internal precision (%RSD) values were .37, 1.3, .69, and 1.5. The precision shows the viability of utilizing HR-ICP-MS analysis for calcium isotope ratios.NSF-REU/NIH Program in Radiochemistr

Fish community response to the addtion of wood in Smith Creek, Virginia

Large woody debris (LWD) is an important component of healthy stream ecosystems. LWD shapes stream physical habitat features, captures and stores organic matter, and serves as shelter, feeding sites, and reproductive substrate for fish and other aquatic organisms. Loss of in-stream LWD and sources of LWD as a result of human activities has negatively impacted many streams. Recently, restoration of in-stream LWD and riparian sources of LWD have become important facets of stream restoration, though many projects involving LWD restoration lack monitoring and evaluation. I evaluated the effects of adding LWD on the fish community in Smith Creek, a small coolwater stream located in Northwest Virginia with a history of habitat degradation due to intense agricultural activity throughout the watershed. I added wooden pallets to previously established fish monitoring stream sections and employed a repeated measures design to examine changes in fish community metrics two years after wood addition. Analyses revealed a significant decrease in density of a dominant benthic species and increase in densitiy of mid-column fish species and a decrease in density of benthic fish species in complex wood treated sections. These results suggest possible interactions between increases in habitat complexity and fish communities in degraded streams. This research can provide valuable information about expected fish community responses to the restoration or addition of LWD in streams and could have implications for future management decisions involving riparian forest management and stream habitat restoration

Reducing Lag in Virtual Displays Using Multiple Model Adaptive Estimation

Multiple Model Adaptive Estimation is an effective method for reducing lag in virtual environment displays. Lag in displays (the time from head motion to the appearance of the proper image on the display) is a significant detriment to realism in virtual environments. Increasing the speed of the computers which control the virtual display is not a final answer. No matter how fast the processors work, there will always be demands to do more. Predicting angular head positions (look-angles) can reduce the lag by allowing the computer to calculate the appropriate scene before it is needed on the display. Single predictors cannot adequately cover the dynamic range of head motion. Using a bank of three elemental filters, lag in head orientation can be significantly reduced when compared to systems with no predictor or the single, nonadaptive Kalman filter predictor proposed by Liang. Predictions lead to small overshoots when the angular velocity of the head reverses direction, but the overshoot lasts for only one frame and is not significantly larger than the nonadaptive predictor

Neutron activation analysis of mercury in petroleum distillates

Abstract only availableIn liquefied natural gas (LNG) plants and nitrogen rejections units (NRU) that utilize aluminum heat exchangers, mercury (Hg) contaminates can result in corrosion of equipment, poisoning of catalysts, mechanical failure, and gas leakage. The purity of the product streams from these plants is also important due to the fact that many of the resulting products such as naphtha are used as feedstock for ethylene production and various solvents. Analytical methods such as chemical extractions (CE), combustion/trap (CT), atomic fluorescent spectrometry (AFS), and inductively coupled plasma optical emission spectrometry (ICP-OES) have been used to measure mercury in petroleum distillates. These methods require extensive sample preparation. A mercury analytical method that can be applied to distillates in routine operation that minimizes mercury loss from sampling preparation is needed. Neutron Activation Analysis (NAA) is a sensitive analytical technique that can be applied to samples as received. The objective of this work was to develop a NAA procedure for testing Hg in naphtha. Virgin naphtha samples were spiked with Hg at concentrations of 20, 50, 200, 500, 1000 and 1500 ng/g. One set of samples were prepared 3 days prior to irradiation and the second set was prepared and irradiated the same day. Analysis of the samples proved that even at small samples sizes (~800 µl) concentrations of 50 to 1500 ng/g of mercury in naphtha are easily detected and give a linear response. Samples that were prepared and irradiated on the same day showed less Hg loss than those prepared 3 days prior to irradiation. Analysis of multiple (n=5) 200 ng/g samples yielded a precision of 9% RSD. The minimum detectable amount of Hg using this technique is 5 ng.NSF-REU Radiochemistr

Emerging Issues: A Global Analysis: Legal Recognition and Equal Treatment of Transgender Citizens

Transgender individuals across nations have been subjected to a range of restrictive barriers, which limit their legal recognition of fundamental rights and protections. These obstacles place a stigma on transgender individuals, subjecting the community to a wide range of discrimination. These boundaries range in severity; some countries simply impose restrictions of use for certain facilities, while other countries resort to physical abuse. Recently, certain countries have enacted laws to give transgender members the same legal recognition that other citizens are afforded while other countries fail to accept the transgender community and continue to uphold restrictive barriers