A Framework for implementing radiation-tolerant circuits on reconfigurable FPGAs

The outstanding versatility of SRAM-based FPGAs make them the preferred choice for implementing complex customizable circuits. To increase the amount of logic available, manufacturers are using nanometric technologies to boost logic density and reduce prices. However, the use of nanometric scales also makes FPGAs particularly vulnerable to radiation-induced faults, especially because of the increasing amount of configuration memory cells that are necessary to define their functionality. This paper describes a framework for implementing circuits immune to radiation-induced faults, based on a customized Triple Modular Redundancy (TMR) infrastructure and on a detection-and-fix controller. This controller is responsible for the detection of data incoherencies, location of the faulty module and restoration of the original configuration, without affecting the normal operation of the mission logic. A short survey of the most recent data published concerning the impact of radiation-induced faults in FPGAs is presented to support the assumptions underlying our proposed framework. A detailed explanation of the controller functionality is also provided, followed by an experimental case study

Lipid peroxidation and antioxidant responses in zebrafish models after exposure to low doses of ionizing radiation

OBJECTIVES: The use of zebrafish – Danio rerio – has grown considerably, demonstrating the increasing interest to use this model in biomedical research, essentially because of the level of homology shared with the human genome, complemented by an easy and reasonably affordable practical side. This work aims to study the radiobiological effects of exposure to low doses of ionizing radiation

Stunning tiroideu: uma abordagem técnica às suas causas, consequências e soluções.

Objectivos – Compreender o contributo da Medicina Nuclear num contexto de carcinoma diferenciado da tiróide (CDT). Debater a pertinência da cintigrafia de pesquisa pré-terapêutica com Iodo-131 (131I) na preparação do tratamento com o mesmo radionuclídeo. Entender o fenómeno stunning ou atordoamento tiroideu, as suas causas, consequências e soluções. Apontar e discutir as principais semelhanças e diferenças entre uma cintigrafia de pesquisa pré-terapêutica com 131I e o mesmo estudo mas com Iodo-123 (123I)

Electrochemical study of nickel(salen) and cobalt(salen) derivatives complexes in the presence of unsaturated halides

The electrochemical intramolecular cyclisation of allyl 2-bromophenyl ethers in N,N'-dimethylformamide at constant current in a diaphragmless cell has been developed using Ni(II) and Co(II) complexes as electron-transfer mediators. Cyclic compounds are obtained in good yields under appropriate experimental conditions

A Multi-Agent Control Architecture for Supply Chains using a Predictive Pull-Flow Perspective

Com o apoio RAADRI.Supply chains are large-scale distribution networks in which multiple types of commodities are present. In this paper, the operations management in supply chains is posed as a tracking control problem. All inventory levels in the network should be kept as close as possible to the desired values over time. The supply chain state is disturbed due to client demand at the end nodes. A multiagent control architecture to restore all inventory levels over the supply chain is proposed. First the model for the supply chain is broken down into smaller subsystems using a flow decomposition. The operations management for each subsystem will be decided upon by a dedicated control agent. The control agents solve their problems using a pull-flow perspective, starting at the end nodes and then propagating upstream. Adding new components to the supply chain will have as a consequence the inclusion of more control agents. The proposed architecture is easily scalable to large supply chains due to its modular feature. The multi-agent control architecture performance is illustrated using a supply chain composed of four levels (suppliers, consolidation, distribution, end nodes) using different levels of predictions about client demands. With the increase of prediction demand accuracy the proposed control architecture is able to keep the desired inventory level at the end nodes over time, which makes it suitable for use for just in time production strategies

Zebrafish and Nuclear Medicine methods and techniques: an each-day improving partnership

Aims: This work aims the introduction of zebrafish as a very promising and each day more interesting animal model in radiobiology. It will be briefly discussed the most relevant advantages and disadvantages related with the use of zebrafish, mentioning some of the previous studies using this model in Nuclear Medicine and concluding with its potential applications

Comparative study between two distinct methods for attenuation correction and the use of no-attenuation correction for the assessment of relative uptake of 99mTc-DMSA on pediatric patients

Although relative uptake values aren’t the most important objective of a 99mTc-DMSA scan, they are important quantitative information. In most of the dynamic renal scintigraphies attenuation correction is essential if one wants to obtain a reliable result of the quantification process. Although in DMSA scans the absent of significant background and the lesser attenuation in pediatric patients, makes that this attenuation correction techniques are actually not applied. The geometric mean is the most common method, but that includes the acquisition of an anterior (extra) projection, which it is not acquired by a large number of NM departments. This method and the attenuation factors proposed by Tonnesen will be correlated with the absence of attenuation correction procedures. Material and Methods: Images from 20 individuals (aged 3 years +/- 2) were used and the two attenuation correction methods applied. The mean time of acquisition (time post DMSA administration) was 3.5 hours +/- 0.8h. The absence of attenuation correction showed a good correlation with both attenuation methods (r=0.73 +/- 0.11) and the mean difference verified on the uptake values between the different methods were 4 +/- 3. The correlation was higher when the age was lower. The attenuation correction methods correlation was higher between them two than with the “no attenuation correction” method (r=0.82 +/- 0.8), and the mean differences of the uptake values were 2 +/- 2. Conclusion: The decision of not doing any kind of attenuation correction method can be justified by the minor differences verified on the relative kidney uptake values. Nevertheless, if it is recognized that there is a need for an accurate value of the relative kidney uptake, then an attenuation correction method should be used. Attenuation correction factors proposed by Tonnesen can be easily implemented and so become a practical and easy to implement alternative, namely when the anterior projection - needed for the geometric mean methodology – is not acquired

Assessing Defragmentation Strategies for FPGAs

Fragmentation on dynamically reconfigurable FPGAs is currently a major obstacle to the efficient management of its logic space. When resource allocation decisions have to be made at run-time a relocation of currently running functions may be necessary to release enough contiguous resources to implement incoming functions.Relocation should take into account any specifics of functions functionality and also those of the FPGAs architecture as to not affect systems performance. A simple and fast method to assess performance degradation of a function during relocation is proposed in this paper. This method is based on previous function labelling and on the concept of proximity vectors

Assessing radiobiological effects of diagnostic level doses of ionizing radiation on zebrafish using comet assay

This paper relates with the application of zebrafish – Danio rerio – to the study of radiobiological effects of medical diagnostic level – low doses – of ionizing radiation. In recent years, the use of zebrafish has grown considerably, pointing more and more as a very interesting model in biomedical research, essentially because of the level of homology shared with the human genome, complemented by an easy and reasonably affordable practical side

Single Low-Dose Ionizing Radiation Induces Genotoxicity in Adult Zebrafish and its Non-Irradiated Progeny

This study investigated to what extent a single exposure to low doses of ionizing radiation can induce genotoxic damage in irradiated adult zebrafish (Danio rerio) and its non-irradiated F1 progeny. Four groups of adult zebrafish were irradiated with a single dose of X-rays at 0 (control), 100, 500 and 1000 mGy, respectively, and couples of each group were allowed to reproduce following irradiation. Blood of parental fish and whole-body offspring were analysed by the comet assay for detection of DNA damage. The level of DNA damage in irradiated parental fish increased in a radiation dose-dependent manner at day 1 post-irradiation, but returned to the control level thereafter. The level of DNA damage in the progeny was directly correlated with the parental irradiation dose. Results highlight the genotoxic risk of a single exposure to low-dose ionizing radiation in irradiated individuals and also in its non-irradiated progeny.info:eu-repo/semantics/publishedVersio