Pocket nickel cadmium cell and battery evaluation

The Nickel Cadmium 129-ampere hour cell was tested in order to characterize the cell under controlled conditions. Results of charge characterization and discharge characterization are reported. Ampere hour efficiency, open circuit stand, and cycle life operation results are included. The battery is briefly described

Instrumental considerations and applications of elemental bio‐imaging

University of Technology, Sydney. Faculty of Science.Elemental Bio-Imaging (EBI) is an established application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) that determines spatial distributions of in situ trace element concentrations in thin sections of biological tissues. This project provides an examination of instrumental considerations relating to method development and refinement, and the utilisation of amended methods for the analysis of element concentration distributions in specific biological samples. The first instrumental consideration examined improving the methods used for matrixmatched tissue standard preparation. The main disadvantage to the previously proposed tissue standard preparation was a decrease in the homogeneity of sectioned tissue as the concentrations of spiked elements increased. The decrease in homogeneity was due to the use of relatively low concentration (1000 μg mL-1) certified single element standard solutions. Substituting the low concentration solutions for higher concentration solutions, prepared using soluble metal salts, allowed for smaller quantities of solution to be spiked into the tissue. This increased homogeneity and the ability to spike a greater number of analytes into each tissue standard. The appropriateness of increasing laser scan speed for the reduction of total experimental analysis time was also examined. EBI experiments normally employ scan speeds where the distance traversed in one second is equal to or less than the diameter of the laser beam. Consequently, data for a higher‐resolution (pixel size = 15 μm x 15 μm) image of a 5 mm x 5 mm tissue section can take upwards of 30 hours to acquire. Appropriate laser scan speeds may be calculated by consideration of the relationship between laser scan speed, laser spot diameter and the total scan cycle of the quadrupole mass analyser. A simple method to calculate the laser scan speeds capable of reducing the acquisition time by up to a factor of five whilst maintaining dimensional integrity of the image is presented in this thesis. Two applications were developed utilising increased laser scan speeds. Both applications were related to the study of the neurodegenerative disorder, Alzheimer’s disease, and examined particular variables and their effects on the distribution of metals in the brain. The first application examined the effectiveness of a new drug, PBT-2, on the redistribution of elements in mouse brains with the zinc transporter-3 gene removed. Results indicated PBT‐2 had little effect on the distribution of 66Zn, 63Cu and 56Fe in the midbrain. The second application examined the effect of intermittent hypoxia and a diet of advanced glycation end‐products on element distribution in the brain. The most intriguing results were seen in the images for 59Co. A 100-fold elevation in the concentrations of 59Co was observed between mice exposed to intermittent hypoxia, those in a control environment and wild-type mice not exposed to the experiment’s settings. An examination into the use of H2 as a reaction gas was conducted. The improvement of the analytical performance of imaging experiments was considered for a range of masses with spectral interferences, including the 40Ar16O+ spectral interference on 56Fe+. At low (< 1.0 mL min-1) H2 flow rates, greater spectral interference due to H+ adducts were observed for 57Fe than with the reaction mode off. At higher flow rates, up to 3.0 mL H2 per minute, the spectral interferences were reduced leading to an improvement in the limits of analysis for masses with O- and N-based polyatomic interferences. EBI is typically performed using spatial resolutions of 30 μm x 30 μm and above. Higher resolution imaging is desirable for many biological applications. As a culmination of the project, the combination of the use of improved matrix‐matched tissue standards with the use of the reaction cell and increased image acquisition speeds was employed. The combination of improved parameters resulted in a high quality image of the area of the brain including the substantia nigra being prepared at a resolution of 6 μm x 6 μm for 56Fe

Development of single-cell protectors for sealed silver-zinc cells

Three design approaches to cell-level protection were developed, fabricated, and tested. These systems are referred to as the single-cell protector (SCP), multiplexed-cell protector(MCP). To evaluate the systems 18-cell battery packs without cell level control were subjected to cycle life test. A total of five batteries were subjected to simulate synchronous orbit cycling at 40% depth of discharge at 22C. Batteries without cell-level protection failed between 345 and 255 cycles. Cell failure in the cell level protected batteries occurred between 412 and 540. It was determined that the cell-level monitoring and protection is necessary to attain the long cycle life of a AgZn battery. The best method of providing control and protection of the AgZn cells depends on the specific application and capability of the user

Development of single cell protectors for sealed silver-zinc cells, phase 1

A single cell protector (SCP) assembly capable of protecting a single silver-zinc (Ag Zn) battery cell was designed, fabricated, and tested. The SCP provides cell-level protection against overcharge and overdischarge by a bypass circuit. The bypass circuit consists of a magnetic-latching relay that is controlled by the high and low-voltage limit comparators. Although designed specifically for secondary Ag-Zn cells, the SCP is flexible enough to be adapted to other rechargeable cells. Eighteen SCPs were used in life testing of an 18-cell battery. The cells were sealed Ag-Zn system with inorganic separators. For comparison, another 18-cell battery was subjected to identical life test conditions, but with battery-level protection rather than cell-level. An alternative approach to the SCP design in the form of a microprocessor-based system was conceptually designed. The comparison of SCP and microprocessor approaches is also presented and a preferred approach for Ag-Zn battery protection is discussed

Habitat-Based Intraguild Predation By Caribbean Reef Octopus Octopus Briareus on Juvenile Caribbean Spiny Lobster Panulirus Argus

Intraguild predation occurs when species simultaneously compete for resources and interact as predator and prey, which describes the interaction between juvenile Caribbean spiny lobster Panulirus argus and Caribbean reef octopus Octopus briareus in the Florida Keys, USA. Octopuses are notorious predators of decapod crustaceans, and their use of crevice shelters suggests that they may also compete for shelter with their lobster prey. Lobsters use mainly chemical cues to detect and avoid octopus, so we hypothesized that the negative association between these species may be as much the consequence of avoidance of a superior competitor as it is of direct predation. Surveys of lobsters and octopuses occupying artificial shelters at 19 hard-bottom sites confirmed that lobsters do not share dens with octopuses, and also show that lobster and octopus abundances are negatively correlated. Tethering experiments on a subset of those sites revealed that predation on lobster was indeed higher on sites with more octopuses. Results from mesocosm studies indicated that although juvenile lobsters do not attain a size refuge from octopus predation, the presence of alternative prey and lobster conspecifics reduces the risk of predation on lobster by octopus. Mesocosm experiments also showed that octopuses were the competitive dominants when shelter was limited. Thus, the negative association between lobster and octopus in the field appears to be driven by both predation and avoidance of octopus-rich sites by lobsters, rather than competition per se. However, crevice shelters suitable for juvenile lobster are limited in many hard-bottom areas in the Florida Keys, so areas where octopuses are abundant may further limit the local accessibility of shelters for juvenile spiny lobsters even if the direct effects of predation by octopus are minimal

Functional effects of polymorphisms on glucocorticoid receptor modulation of human anxiogenic substance-P gene promoter activity in primary amygdala neurones

This work was funded by The BBSRC (BB/D004659/1) the Wellcome Trust (080980/Z/06/Z) and the Medical Research Council (G0701003). Colin Hay was funded by the Chief Scientist Office, Scotland. Scott Davidson was funded by a BBSRC strategic studentship (BBS/S/2005/12001). Philip Cowie was funded by the Scottish Universities Life Sciences Alliance (SULCA).Peer reviewedPublisher PD

Developmental Expression of Elements of Hepatic Cholesterol Metabolism In The Rat

The expression of several key enzymes and receptors of rat hepatic cholesterol metabolism was studied during development. Among major findings were: acyl coenzyme A:cholesterol acyltransferase, the cholesteryl ester hydrolases, cholesterol-7 alpha-hydroxylase and the alpha 2-macroglobulin receptor (LRP) were very low in fetal livers, but all were induced shortly before birth, suggesting that these elements are important for extrauterine life. Although the other elements continued to increase, by day 6 of postnatal life, cholesterol-7 alpha-hydroxylase had reached undetectable levels. It reappeared by day 12 of suckling, placing it in the group of late-appearing activities necessary for the fully mature hepatic phenotype. Changes in acyl coenzyme A:cholesterol acyltransferase activity appeared due predominantly to changes in amount of active protein. The cholesteryl ester hydrolase (CEH) activities all showed different developmental patterns, suggesting that each was a unique activity. The bile salt- dependent CEH activity was much higher in the suckling period than in the adult where it was almost undetectable, suggesting that this CEH may have its major importance in the suckling period of development. Low density lipoprotein receptors exhibited a pattern very different from that of the alpha 2-macroglobulin receptors and did not show consistent correlation with any other elements. At some developmental time points, the relationships amongst the elements differed significantly from the adult pattern. These studies provide for the first time an integrated picture of developmental expression of key elements of hepatic cholesterol metabolism and set the stage for further studies on their modes of regulation

Quantum Decoherence in a D-Foam Background

Within the general framework of Liouville string theory, we construct a model for quantum D-brane fluctuations in the space-time background through which light closed-string states propagate. The model is based on monopole and vortex defects on the world sheet, which have been discussed previously in a treatment of 1+1-dimensional black-hole fluctuations in the space-time background, and makes use of a T-duality transformation to relate formulations with Neumann and Dirichlet boundary conditions. In accordance with previous general arguments, we derive an open quantum-mechanical description of this D-brane foam which embodies momentum and energy conservation and small mean energy fluctuations. Quantum decoherence effects appear at a rate consistent with previous estimates.Comment: 16 pages, Latex, two eps figures include