1,564 research outputs found
An energy efficient approach for radon management in a HVAC environment: executive summary
No full textRadioactive radon gas, after being released from rocks, soils and building structures, can pose a significant health threat to the building occupants. This is of particular concern in tight HVAC (Heating, Ventilating and Air-Conditioning) serviced buildings where there is re-circulating air with limited fresh air intake. A thorough survey was initiated at the Hong Kong University of Science and Technology (HKUST) in 1996 and results indicate a radon average concentration of 107 Bq/m3, which is approximately 50% of the World Health Organisation's (WHO) recommended standard (200 Bq/m3). About 10% of the measurements were in excess of this WHO limit, while 46% of the samples also showed average peak radon concentrations (264 Bq/m3) in excess of this WHO limit.
To overcome these elevated indoor radon concentrations, their characteristics at HKUST was studied. Radon level was found to increase linearly as a function of the length of the HVAC shut off period, and decrease exponentially upon system resumption. Radon level predictive models were developed after a series of room chamber experiments with modification factors defined to account for the indoor sinks in an effort to enhance the accuracy and applicability of the models.
Following a campus-wide energy audit, two energy efficient radon management approaches were derived from the predictive models and were subsequently integrated into the existing HKUST operations. The first was defined as an Active Radon Control Approach (ARCA), where HVAC operation schedules were modified to yield an energy saving potential of around HK$2.7 Million a year. ARCA is optimised to reduce the radon dose to the HKUST occupants following the radiation protection principle of "As Low as Reasonably Achievable (ALARA)", and with considerations of economical and operational constraints.
The other was a Passive Radon Control Approach (PRCA) using Polyurethane-based (P-u) paint to cover building material surfaces to reduce the radon emission
Ionizing and non-ionizing radiation and the risk of childhood cancer-illustrated with domestic radon and radio frequency electromagnetic field exposure
No full textBackground
Children are exposed to many different environmental factors, including exposure to low-dose ionizing radiation and to non-ionizing radiation.
Low-dose ionizing radiation comprises anthropogenic modified radiation and natural ionizing radiation from cosmic rays from the atmosphere, terrestrial gamma radiation from radionuclides in rocks and soils and radiation from radon.
Non-ionizing radiation comprises optical radiation and radiation from electromagnetic fields. The latter comprises radiation from extremely low-frequency electromagnetic fields (ELF-EMF; high voltage power lines, electrical installations) and radiofrequency electromagnetic fields (RF-EMF; broadcast transmitters, mobile phone base stations, mobile and cordless phones).
Both ionizing and non-ionizing radiation are assumed to be associated with childhood cancer.
Aims
Within this dissertation, we primarily aimed to assess whether there is an association between domestic radon exposure and childhood cancers. We further investigated whether there is an association between low-dose ionizing gamma radiation and childhood cancers. We finally assessed whether there is an association between RF-EMF exposure from broadcast transmitters and childhood cancers.
Methods
We performed prospective census-based cohort designs, considering all children, aged less than 16 years and living in Switzerland at the date of census 2000 (December 5th 2000). Time at risk was set to begin at census and lasted until the date of diagnosis, death, emigration, a child’s 16th birthday or until the end of the year 2008. In terms of non-ionizing radiation from far-field RF-EMF sources from broadcast transmitters, we carried out a further prospective cohort analysis, considering all children, aged less than 16 years and living in Switzerland between 1985 and 2008.
We assessed exposure at baseline (date of census 2000) for each child’s home address. For the analyses on RF-EMF exposure to broadcast transmitters and childhood cancers where a longer follow-up was considered, we considered exposure at the time of diagnosis.
For the analyses on domestic radon exposure and childhood cancers, exposure assessment was based on a nationwide radon prediction model. For the analyses on low-dose ionizing gamma radiation and childhood cancers, exposure assessment was based on modelled and measured dose rates from outdoor gamma radiation. For the analyses on RF-EMF exposure to broadcast transmitters and childhood cancers, exposure assessment was based on modeled field strengths.
Results
We estimated arithmetic mean radon concentrations to be 85.7 Bq/m³ (range: 6.9-337.2 Bq/m³) for childhood cancer cases and 85.9 Bq/m³ (range: 0.7-490.1 Bq/m³) for the rest of the study population. Despite relative high radon levels in Switzerland, we found no evidence for an association between domestic radon exposure and childhood cancers.
We found increased leukaemia risk (including acute lymphoblastic leukaemia) with respect to gamma radiation for children who lived at the same address between 1995 and 2000.
Finally, we found no increased leukaemia risk but increased central nervous system (CNS) tumour risks with respect to RF-EMF exposure from broadcast transmitters.
Conclusions and Outlook
The findings of our analyses, indicating no association between domestic radon exposure and childhood cancers were consistent with past studies that estimated doses of domestic radon concentrations for different body organs (lung, red bone marrow, brain).
The results of the analyses on gamma radiation and childhood cancers indicate that low dose ionizing gamma radiation might be relevant in terms of childhood leukaemia. These results were also found to be consistent with dose estimations for different body organs (red bone marrow, brain). They indicated that the same gamma radiation dose to the red bone marrow over a longer time period is probably necessary for gamma radiation to lead to childhood leukaemia.
The findings from the analyses on RF-EMF exposure from broadcasting and childhood leukaemia were found to be consistent with results from animal, in-vitro and laboratory studies. On the contrary, the findings indicating increased CNS tumours from RF-EMF exposure to broadcast transmitters contradict results from former studies. Our results are further in contradiction to a previous case-control study on wireless phones. This study could not find an increased risk for CNS tumours from the use of wireless phones that lead to substantially higher exposure to the head.
Although no evidence for an association with childhood cancers was found, domestic radon exposure is of public health relevance with regard to lung cancer in adults.
The findings from the analyses on gamma radiation and childhood cancers indicate that gamma radiation is of public health relevance as well, especially when children are exposed to the same gamma radiation dose over a longer time period.
Statements on possible public health relevance concerning non-ionizing radiation of RF-EMF from broadcasting on the other hand are not yet possible, as the results for CNS tumours need further clarification
Beam Synthesis Based on Inverse Discrete Radon Transform for Linear Pulsed Arrays
No full textThis letter presents an investigation of possibilities
A method for direct beam synthesis in linear pulsed
arrays of isotropic transmitters has been presented. By using the discrete Radon transform (DRT) and its inverse (IDRT), a known Radon transform framework has been adapted for gaining insight into a noniterative beamforming method. Theoretical analysis and numerical modeling, which validate this method, were conducted
Relationship between biodistribution of a novel thymidine phosphorylase (TP) imaging probe and TP expression levels in normal mice
No full textObjective: Thymidine phosphorylase (TP) is a key enzyme in the pyrimidine nucleoside salvage pathway and its expression is upregulated in a wide variety of solid tumors. In mice, we previously observed high and specific accumulation levels of our TP imaging probe, radioiodinated 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU) not only in high-TP-expressing tumors, but also in the liver and small intestine. To clarify the reason for the high accumulation levels of radioiodinated IIMU in the liver and small intestine, we investigated the expression levels of TP in mice in comparison with the biodistribution of radioiodinated IIMU (123I-IIMU). Methods: BALB/cCrSlc mice were injected with 123I-IIMU, and the radioactivity levels [%ID/g (normalized to a mouse of 25 g body weight)] in the tissues of interest were determined 0.5, 1, 3 and 24 h after the injection (n = 5, each time point). To determine the expression levels of TP, BALB/cCrSlc and ddy mice (n = 3/each strain) were euthanized, and the heart, liver, lung, spleen, kidney, stomach, small intestine, large intestine and brain were collected. The mRNA and protein expression levels of TP in these organs were examined by quantitative reverse transcription-polymerase chain reaction and western blot analyses, respectively. Results: In BALB/cCrSlc mice administered 123I-IIMU, markedly high radioactivity levels were observed in the liver [1.568 ± 0.237 (%ID/g)] and small intestine [0.506 ± 0.082 (%ID/g)], whereas those in the other tissues were fairly low [<0.010 ± 0.003 (%ID/g)] 30 min after the injection. The highest expression levels of TP mRNA were also observed in the liver and small intestine among the tissues tested. Immunoblotting showed intense immunoreactive bands of the TP protein for the liver and small intestine, whereas no notable bands were detected for other tissues. Similar expression profiles of TP mRNA and protein were observed in ddy mice. Conclusion: We confirmed TP expression in various tissues of mice at the mRNA and protein levels: high TP expression levels were observed in the liver and small intestine. These high TP expression levels are consistent with the high accumulation levels of 123I-IIMU in these tissues. Our results may provide important information about the physiological accumulation of 123I-IIMU, which may be useful for the clinical diagnostic imaging of TP
Raw data for all grab samples and radon survey samples in this study.
No full textGrab sample data are categorized by type (groundwater–gw, surface water–surf, and well) and location. Date collected and lat long indicate the sampling date and location of sampling. Rn concentrations (Bq/m3), temperature (°C), and salinity are given for each grab sample. Additionally, nutrient data (TN, TP, DIP, DSi, NOx, NH4+, DIN, and DON) are provided in μM. Radon survey data show location (lat long), date and time of measurement, water depth (m), salinity, and temperature (°C), and the radon concentration (Bq/m3). (XLSX)</p
TP-model transformation-based-control design frameworks
No full textThis book covers new aspects and frameworks of control, design, and optimization based on the TP model transformation and its various extensions. The author outlines the three main steps of polytopic and LMI based control design: 1) development of the qLPV state-space model, 2) generation of the polytopic model; and 3) application of LMI to derive controller and observer. He goes on to describe why literature has extensively studied LMI design, but has not focused much on the second step, in part because the generation and manipulation of the polytopic form was not tractable in many cases. The author then shows how the TP model transformation facilitates this second step and hence reveals new directions, leading to powerful design procedures and the formulation of new questions. The chapters of this book, and the complex dynamical control tasks which they cover, are organized so as to present and analyze the beneficial aspect of the family of approaches (control, design, and optimization). Additionally, the book aims to convey simple TP modeling; a new convex hull manipulation based possibilities for optimization; a general framework for stability analysis; standardized modeling and system description; relaxed and universal LMI based design framework; and a gateway to time-delayed systems
Spatio-temporal alignment and hyperspherical radon transform for 3D gait recognition in multi-view environments
No full textThis paper presents a view-invariant approach to gait recognition in multi-camera scenarios exploiting a joint spatio-temporal data representation and analysis. First,
multi-view information is employed to generate a 3D voxel reconstruction of the scene under study. The analyzed subject
is tracked and its centroid and orientation allow recentering and aligning the volume associated to it, thus obtaining a representation invariant to translation, rotation and scaling. Temporal periodicity of the walking cycle is extracted to align the input data in the time domain. Finally,
Hyperspherical Radon Transform is presented as an efficient tool to obtain features from spatio-temporal gait templates for classification purposes. Experimental results
prove the validity and robustness of the proposed method for gait recognition tasks with several covariates.Postprint (published version
The prediction theory of stationary random fields. III. Fourfold Wold decompositions
No full textAbstractIn this paper, we investigate various fourfold Wold-type decompositions of stationary random fields under different hypotheses of commutation properties. Spectral characterizations of the three multiplicities of the innovation subspaces are obtained. The equivalence relations between the weak commutation property, fourfold Wold-type decomposition, and quarter-plane moving average representation are proved. A complete spectral characterization of the weak commutation property is also given
IGD-TP Competence Maintenance, Education and Training Strategy and Action Plan for 2013-2016: DELIVERABLE (D-N°:3.2) Work Package 3
No full textThe purpose of this document is to define how the working group on Competence Maintenance, Education and Training (CMET) can support the IGD-TP Vision "2025". Also it was and it is still intended for outlining the activities of this working group and Joint Activity (no 14) during 2013-2016. In connection with its Vision statement (IGD-TP 2009 Vision Report) the IGD-TP committed to among its other goals to "Facilitate access to expertise and technology and maintain competences in the field of geological disposal for the benefit of Member States". The CMET working group was established in 2012 when its first Terms of Reference (ToR) version was approved by the IGD-TP Executive Group (EG). During 2013-2015 resourcing to support the group was received under SecIGD2 project with the EURATOM FP7 grant and with a direct contribution from the IGD-TP Executive Group members. This document was planned for production already during the first SecIGD2 project year. It was to be based on the needs of the IGD-TP's Joint Activities that were already deployed or planned to start in 2012, and on the needs of the CMET group members. The role of CMET group was to address Competence Maintenance, Education and Training needs from the demand side. However, at the early stage of deployment, it was somewhat difficult to express or the identify competence gaps in the activities or they had already been identified and resourced at the beginning of the joint activity. Thus there was not adequate amount of input for the first CMET working group meeting as a direct basis for a strategy formulation beyond the action plan, which had been prepared for the SecIGD2 project proposal. The SecIGD2 project's Work Package 3 in the project's description of work (DoW) that was originally prepared in alignment with the CMET Terms of Reference included the main action plan for the CMET group. With the exception of this document, the actions foreseen to be carried out by the CMET in the action plan have been implemented according to the original timetable. The actions are described in this report and two other public project documents, which are included in this report's references. The CMET working group members have contributed to the content of this report either directly via email commenting or by participating in the work group meeting discussion providing input to this report. The editors mentioned on this report's front page have been the persons who have produced this report document itself. The document represents the views of the authors and of the CMET working group. This document does not represent the views of the IGD-TP Executive Group.Geo-engineerin
The design and validation of a low-cost trans perineal (TP) prostate biopsy simulator for training: improving trainees' confidence and cognitive targeting skills.
No full textThe aim of this research was to create a novel and low-cost TP prostate biopsy simulator that has face, content and construct validity with high educational value. This research developed a trans perineal prostate (TP) biopsy simulator using 3D-printed moulds and tissue-mimicking materials. Important regions (anterior, mid, and posterior zones) were coded with different colours. Ultrasound visible abnormal lesions were embedded in the prostate phantom. Expert and novice participants in TP biopsies were recruited. Essential skills were identified through the consensus of six experts. These skills were assessed through tasks performed by participants. This included the accuracy and timing of systematic and target biopsies. Immediate feedback was determined by the colour of the biopsy cores taken. A survey was distributed to evaluate its realism and educational value. The material cost of one simulator was £7.50. This simulator was proven to have face, content, and construct validity. There was a significant difference (p = 0.02) in the accuracy of systematic biopsies between both experts and novices. Significant difference was also observed (p = 0.01), in accurately identifying target lesion on ultrasound between both groups. Participants rated the overall realism of the simulator 4.57/5 (range 3-5). 100% of the experts agreed that introducing this simulator to training will be beneficial. 85.7% of the participants strongly agree that the simulator improved their confidence in TP biopsies. There is value in integrating this proof-of-concept TP prostate biopsy simulator into training. It has highly rated educational value and has face, content, and construct validity. [Abstract copyright: © 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
- …
