Three penetrating captive bolt (PCB) placements were tested on cadaver heads from swine with estimated body weight (BW) >200 kg (sows = 232.9 ± 4.1 kg; boars = 229.3 ± 2.6 kg). The objectives were to determine tissue depth, cross-sectional brain area, visible brain damage (BD), regions of BD, and bolt-brain contact; and determine relationships between external head dimensions and tissue depth at each placement. A Jarvis PAS – Type P 0.25R PCB with a Long Stunning Rod Nosepiece Assembly and 3.5 gr power loads was used at the following placements on heads from 111 sows and 46 boars after storage at 2-4° C for approximately 62 h before treatment: FRONTAL (F) – 3.5 cm superior to the optic orbits at midline, TEMPORAL (T) – at the depression posterior to the lateral canthus of the eye within the plane between the lateral canthus and the base of the ear, or BEHIND EAR (BE) – directly caudal to the pinna of the ear on the same plane as the eyes and targeting the middle of the opposite eye. For sows, the bolt path was in the plane of the brain for 42/42 (100%, 95% CI: 91.6-100.0%) F heads, 39/40 (97.5%, 95% CI: 86.8-99.9%) T heads, and 34/39 (87.5%, 95% CI: 72.6-95.7%) BE heads; for the heads that could reliably be assessed for BD damage was detected in 25/26 (96.2%, 95% CI: 80.4-99.9%) F heads, 24/35 (68.6%, 95% CI: 50.7-83.2%) T heads, and 5/40 (12.5%, 95% CI: 4.2-26.8%) BE heads. For boars, the bolt path was in the plane of the brain for 17/17 (100.0%, 95% CI: 80.5-100.0%) F heads, 18/18 (100.0%, 95% CI: 81.5-100.0%) T heads, and 14/14 (100.0%, 95% CI: 76.8-100.0%) BE heads; damage was detected in 11/12 (91.7%, 95% CI: 61.5-99.8%) F heads, 2/15 (13.3%, 95% CI: 1.7-40.5%) T heads, and 7/14 (50.0%, 95% CI: 23.0-77.0%) BE heads. Tissue depth was reported as mean ± standard error followed by 95% one-sided upper reference limit (URL). For sows, total tissue thickness was different (P < 0.05) between placements (F: 52.7 ± 1.0 mm, URL: 64.1 mm; T: 69.8 ± 1.4 mm, URL: 83.9 mm; BE: 89.3 ± 1.5 mm, URL: 103.4 mm). In boars, total tissue thickness was different (P < 0.05) between placements (F: 41.2 ± 2.1 mm, URL: 56.3 mm; T: 73.2 ± 1.5 mm, URL: 83.4 mm; BE: 90.9 ± 3.5 mm, URL: 113.5 mm). For swine > 200 kg BW, F placement may be more effective than T or BE due to less soft tissue thickness, which may reduce concussive force. The brain was within the plane of bolt travel for 100% of F heads with brain damage for 96.2% and 91.7% of F sow and boar heads, respectively.
This paper describes an approach to measuring extinct fission products that would allow for the characterization of a nuclear test at any time. The isotopic composition of molybdenum in five samples of glassy debris from the 1945 Trinity nuclear test has been measured. Nonnatural molybdenum isotopic compositions were observed, reflecting an input from the decay of the short-lived fission products 95 Zr isotopes formed in the nuclear detonation. Together with a determination of the amount of plutonium in the debris, these measurements of extinct fission products allow for new estimates of the efficiency and yield of the historic Trinity test.nuclear forensics | nuclear testing | treaty monitoring | stable isotope perturbation measurements T he ability to confirm the occurrence and nature of a nuclear test is essential to modern nuclear treaty monitoring (1). A robust multination monitoring system is in place for underground nuclear tests, relying primarily on seismic signals and other prompt measures (1-3). Radiochemical measurements of actinides and fission products are also an integral part of treaty monitoring, but these too are time sensitive, relying on immediate access to samples containing short-lived radionuclides (3). In particular, the most useful refractory peak-yield fission products are short-lived and no longer detectable radiometrically in the debris from older tests (when months or years have passed since the test). An ability to determine the concentration of extinct fission products in old debris would allow for independent characterization of a nuclear test at any time and could serve as a valuable additional tool for ongoing nuclear nonproliferation and verification endeavors. We report here the first determination, to our knowledge, of the number of fissions that occurred in a nuclear test via high-precision mass-spectrometric measurements of perturbation in Zr fission products. These fission determinations are combined with plutonium measurements to estimate the efficiency and yield of the first nuclear test, Trinity.Seventy years have passed since the Trinity test and the exact yield and performance of the first atomic bomb are still debated. Many estimates of the bomb yield have been published, ranging from 8 to 61 kilotons (kT), with the official US Department of Energy yield of 21 kT based on historic radiochemical measurements (4-6). To determine the plutonium fission efficiency and yield of the Trinity device, a measurement of residual unreacted plutonium and the number of fissions was used (Eq. 1) (7). Although radiochemical measurements were performed in 1945, they were crude relative to modern standards, leaving some uncertainty in the official yield (8).where F total = total number of fissions in the device, Pu ingoing = total number of plutonium atoms in the device, f sample = number of fissions measured in the debris sample, and Pu sample = number of plutonium atoms measured in the debris sample. Although long-lived fission products such as 137 Cs and 90 Sr are detectable in Tr...
New measurement and assessment techniques have been applied to the radiochemical reevaluation of the Trinity Event. Thirteen trinitite samples were dissolved and analyzed using a combination of traditional decay counting methods and the mass spectrometry techniques. The resulting data were assessed using advanced simulation tools to afford a final yield determination of 24.8 ± 2 kilotons TNT equivalent, substantially higher than the previous DOE released value of 21 kilotons. This article is intended to complement the work of Susan Hanson and Warren Oldham, seen elsewhere in this issue. 1
A rapid and simple X-ray fluorescence-based method is reported for characterizing heavy atom derivatives of proteins for protein crystallography using multiple isomorphous replacement (MIR). MIR is a widely used technique for solving protein crystallographic structures which requires that a 'heavy atom' be incorporated into the protein to provide a strong signal in the diffraction pattern. Current methods for determining the effectiveness of these proteinheavy atom reactions are not always successful. In contrast, X-ray fluorescence quickly determines the presence of heavy atom modifications of proteins and the stoichiometry of these modifications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.