NeutralNet: Development and testing of a machine learning solution for pulse shape discrimination.

Accurate description of radiation fields containing neutrons continues to be a difficult task to complete. This difficulty arises because of the inherent sensitivity of neutron detectors to other types of radiation, and the ability of neutrons to generate secondary particles producing mixed field environments. This research looks at the development and performance of various machine learning architectures when applied to the task of pulse shape discrimination with liquid scintillators.

High-rate Gamma Spectrometry Using a LaBr3(Ce) Scintillator with a Fast Pulse Shaping.

The performance of a LaBr3(Ce) gamma spectrometer at high count rates was investigated up to an input count rate of 1.3 Mcps. In order to make its pulse processing faster, a preamplifier provided by the detector manufacturer was eliminated, and the signal from the photomultiplier tube was fed directly to a digital pulse processing system.

Optimization and characterization of a coincidence beta-ray spectrometer.

Aimed at beta spectrometry and dosimetry for mixed beta-gamma fields, a Si-plastic scintillator coincidence beta-ray spectrometer has been developed. The spectrometer collects pure beta-ray spectra by rejecting the gamma-ray detection events through coincidence. Both pulse height and arrival time of each detection event were recorded in list mode by a compact digital processing system.

Isolation of the effects of alpha-related components from total effects of radium at low doses.

Purpose: Radium is the most common source of alpha radiation exposure to humans and non-human species in the environment but the dosimetry is complicated by the decay chain which involves gamma exposure due to radon daughters. This paper seeks to determine the separate contributions of alpha and gamma doses to the total dose and total direct and non-targeted effect in a fish and a human cell line.

Materials And Methods: This study aimed to isolate the effect of alpha particles following exposure to low doses of radium in cells, and their progeny which received no further exposure.

One-Decade-Spanning transgenerational effects of historic radiation dose in wild populations of bank voles exposed to radioactive contamination following the chernobyl nuclear disaster.

The concept of historic radiation doses associated with accidental radioactive releases and their role in leading to radiation-induced non-targeted effects on affected wild animals are currently being evaluated. Previous research studying Fukushima butterfly, Chernobyl bird and fruit fly populations shows that the effects are transgenerational, underlined by the principles of genomic instability, and varied from one species to another. To further expand on the responses of and their sensitivity in different taxonomically distinct groups, the present study sought to reconstruct historic radiation doses and delineate their effects on bank voles (Clethrionomys glareolus) found within a 400-km radius of the Chernobyl Nuclear Power Plant meltdown site.

Effects of historic radiation dose on the frequency of sex-linked recessive lethals in Drosophila populations following the Chernobyl nuclear accident.

Contrary to the effects of high doses of radiation, the effects of low doses of radiation are still being investigated. Low doses and their non-targeted effects in particular are of special interest for researchers. The accident that occurred at the Chernobyl Nuclear Power Plant (NPP) gives researchers the opportunity to view these effects outside of a laboratory environment.

Transgenerational effects of historic radiation dose in pale grass blue butterflies around Fukushima following the Fukushima Dai-ichi Nuclear Power Plant meltdown accident.

Low dose radiation effects have been investigated in Chernobyl for many years but there is uncertainty about initial doses received by many animal species. However, the Fukushima Dai-ichi Nuclear Power Plant accident opens an opportunity to study the effects of the initial low historic dose on directly exposed species and their progeny during a time where the contaminating radionuclides are decaying. In this paper, it is proposed that historic acute exposure and its resulting non-targeted effects (NTEs) may be partially involved in the high mortality/abnormality rates seen across generations of pale grass blue butterflies (Zizeeria maha) around Fukushima.

Development of an advanced two-dimensional microdosimetric detector based on THick Gas Electron Multipliers.

Purpose: The THick Gas Electron Multiplier (THGEM)-based tissue-equivalent proportional counter (TEPC) has been proven to be useful for microdosimetry due to its flexibility in varying the gaseous sensitive volume and achieving high multiplication gain. Aiming at measuring the spatial distribution of radiation dose for mixed neutron-gamma fields, an advanced two-dimensional (2D) THGEM-TEPC was designed and constructed at McMaster University which will enable us to overcome the operational limitation of the classical TEPCs, particularly for high-dose rate fields. Compared to the traditional TEPCs, anode wire electrodes were replaced by a THGEM layer, which not only enhances the gas multiplication gain but also offers a flexible and convenient fabrication for building 2D detectors.

A Pilot Study Measuring Aluminum in Bone in Alzheimer's Disease and control Subjects Using in vivo Neutron Activation Analysis.

Aluminum, being the most abundant metal in the earth's crust, is widely distributed in the environment, and is routinely taken up by the human body through ingestion and inhalation. Aluminum is not considered an essential element and it can be toxic in high concentrations. Most of the body burden of aluminum is stored in the bones.

Ultra-Violet Light Emission from HPV-G Cells Irradiated with Low Let Radiation From (90)Y; Consequences for Radiation Induced Bystander Effects.

In this study, we aimed to establish the emission of UV photons when HPV-G cells and associated materials (such as the cell substrate and cell growth media) are exposed to low LET radiation. The potential role of UV photons in the secondary triggering of biological processes led us to hypothesize that the emission and absorption of photons at this wavelength explain some radiation induced "bystander effects" that have previously been thought to be chemically mediated. Cells were plated in Petri-dishes of two different sizes, having different thicknesses of polystyrene (PS) substrate, and were exposed to β-radiation from (90)Y produced by the McMaster Nuclear Reactor.

In vivo quantification of bone-fluorine by delayed neutron activation analysis: a pilot study of hand-bone-fluorine levels in a Canadian population.

Humans can be exposed to fluorine (F) through their diet, occupation, environment and oral dental care products. Fluorine, at proper dosages, is believed to have positive effects by reducing the incidence of dental caries, but fluorine toxicity can occur when people are exposed to excessive quantities of fluorine. In this paper we present the results of a small pilot in vivo study on 33 participants living in Southwestern Ontario, Canada.

Effect of fluorescent whitening agent on the transcription of cell damage-related genes in zebrafish embryos.

7-Diethylamino-4-methylcoumarin (DEMC) is a fluorescent whitening agent (FWAs). There have been some studies on DEMC's protective effects against biological activity but there are few papers about the in vivo toxicity of DEMC. In this study, we used wild-type zebrafish embryos 3 days post fertilization (dpf).

Effect of dose rate on the radiation-induced bystander response.

Radiation-induced biological bystander effects have become a well-established phenomenon associated with the interaction of radiation with cells. These so-called bystander effects have been seen across a variety of end points for both high and low linear energy transfer (LET) radiations, utilizing a variety of dose rates and radiation sources. In this study, the effect of dose rate and different low LET sources on the bystander cell survival fraction (SF) was examined.

Effective target size for the induction of bystander effects in medium transfer experiments.

Although radiation-induced bystander effects are frequently observed biological phenomena, the mechanism for these effects has not been fully determined. The target-hit theory and related concepts from microdosimetry provide a convenient formalism to help identify the nature of the targets responsible for initiating the emission of diffusible factors in medium transfer experiments. We used the microdosimetric models proposed by Stewart et al.

A dose threshold for a medium transfer bystander effect for a human skin cell line.

The existence of radiation-induced bystander effects mediated by diffusible factors is now accepted, but the mechanisms and precise behavior at low doses remain unclear. We exposed cells to gamma-ray doses in the range 0.04 mGy-5 Gy, harvested the culture medium, and transferred it to unirradiated reporter cells.

Effects of chemical carcinogens and physicochemical factors on the UV spectrophotometric determination of DNA.

The ultraviolet (UV) absorbance ratio of 260/280 nm has been used as an indicator of DNA purity. However, the A260/A280 ratio may be beyond the normal range (1.8-1.