Publications by authors named "Murray Hamilton"

Article Synopsis
  • The study investigates how seasonal changes affect nectar availability for pollinators, specifically comparing early spring with summer conditions.
  • It tests two hypotheses: one suggesting consistent resource limitation throughout the seasons and another proposing more relaxed limitations in spring that become severe later.
  • Results indicate lower nectar depletion in spring compared to summer, supporting the idea of a seasonal mismatch, while highlighting that factors like time of day and different flower types significantly influence nectar availability.
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The optical design of a simple low-cost polarimetric balloon-borne backscatter sonde for detecting cloud thermodynamic phase is described. Simulations are performed to determine the best choice of polarization as well as the layout of the detectors with respect to the emitter. The variety of scattering angles of the detected photons, due to finite size detectors, has at least as great an effect as multiple scattering in determining the ratio of cross-polarized to co-polarized signal.

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The oximes pralidoxime (2-PAM), its dimethanesulphonate salt derivative P2S, and obidoxime (toxogonin) are currently licensed and fielded for the treatment of chemical warfare (CW) organophosphorous (OP) nerve agent poisoning. While they are effective against several of the identified threat CW OP agents, they have little efficacy against others such as soman (GD) and cyclosarin (CF). In addition, they are also significantly less effective than other investigational oximes against the nerve agent known as Russian VX (RVX).

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Wavelength accuracy and stability are key requirements for differential absorption lidar (DIAL). We present a control and timing design for the dual-stabilized cw master lasers in a pulsed master-oscillator power-amplifier configuration, which forms a robust low-cost water-vapor DIAL transmitter system. This design operates at 823 nm for water-vapor spectroscopy using Fabry-Perot-type laser diodes.

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This document will address the contributions of defence research to both military and civilian applications. Compared to civilian research capabilities, particularly in terms of personnel, defence research resources are limited. Additionally, many of the research targets are either classified or involve applications that have (or had) limited civilian use.

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Abstract Combinatorial library screening offers a rapid process for identifying potential therapies to toxins. Hinge peptide libraries, which rely on conformational diversity rather than traditional molecular diversity, reduce the need for huge numbers of syntheses and screening steps and greatly expedite the discovery process of active molecules. Hinge peptide libraries having the structures: Acetyl-X1-X2-hinge-X3-X4-NH2 (capped) and X1-hinge-X2-X3 (uncapped), where X1 through X4 are near-equimolar mixtures of twelve L-amino acids and hinge = 4-aminobutyric acid, were screened for inhibitory activity in bioassays for botulinum neurotoxins A and B (BoNT/A, BoNT/B) and saxitoxin.

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Exposure to the organophosphate nerve agent soman produces seizures that in turn lead to neuropathology. This study describes the temporal and spatial evolution of brain pathology following soman-induced convulsions and the attenuation of these alterations after neuroprotective intervention with magnetic resonance imaging (MRI). Neuroimaging 12 h after soman exposure, the hippocampus and thalamus exhibited significant decreases (23%) in apparent diffusion coefficients (ADC).

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The purpose of this study was to evaluate the efficacy of a novel barrier cream formulation at reducing the percutaneous toxicity of a 2xLD(50) liquid challenge of nerve agent (VX). The study was conducted in vitro and in vivo using the domestic pig. Pretreatment of the (inner ear skin) exposure site with barrier cream eliminated mortality, reduced cholinesterase inhibition and prevented any physiological or biochemical signs of intoxication.

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Anesthetized pigs were injected i.m. with 500 mg HI-6 dichloride (HI-6 2Cl) (1-[[[4-(aminocarbonyl)-pyridinio]methoxy]methyl]-2[(hydroxyimino)methyl]pyridinium dichloride; CAS 34433-31-3)) or the molar equivalent of HI-6 dimethanesulphonate (HI-6 DMS) 633 mg.

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O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate (VX) is an extremely toxic organophosphate nerve agent that has been weaponized and stockpiled in a number of different countries, and it has been used in recent terrorist events. It differs from other well-known organophosphate nerve agents in that its primary use is as a contact poison rather than as an inhalation hazard. For this reason, we examined the effects of application site and skin decontamination on VX toxicity in anesthetized domestic swine after topical application.

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The site specificity of the percutaneous absorption of methyl salicylate (MeS) and the organophosphate nerve agent VX (O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate) was examined in anaesthetized domestic swine that were fully instrumented for physiological endpoints. Four different anatomical sites (ear, perineum, inguinal crease and epigastrium) were exposed to the MeS and the serum levels were measured over a 6-h time period. The dose absorbed at the ear region was 11 microg cm(-2) with an initial flux of 0.

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1. ATP receptors of the P2X class have previously been identified on autonomic nerve endings and on a limited population of CNS neurons. 2.

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