Off-site population radiological dose and risk assessment for potential airborne emissions from the Weldon Spring Site

Radiological doses and health risks to the population around the Weldon Spring site from potential airborne emissions during remedial action at the chemical plant area of the site have been assessed with the Clean Air Act Assessment Package-1988 computer code. Two treatment options are being considered for waste produced by site cleanup activities: chemical stabilization/solidification and vitrification. Over the entire cleanup period of 7 years, the collective dose received by the people who live within 80 km (50 mi) of the site (about 3 million persons) is estimated to be about 34 person-rem for the chemical stabilization/ solidification option and 32 person-rem for the vitrification option. By comparison, the same population is expected to receive about 6 [times] 10[sup 6] person-rem from natural background radiation during that time. If only the population within a reasonable radius of impact is considered (about 10,700 persons live within 5 km [3 mi] of the site), the remedial action activities are estimated to result in about 5 person-rem over the entire cleanup period; the same population is expected to receive about 20,000 person-rem from natural background radiation during that time. Because the doses are low, no cancers or genetic effects are expected to occur among the population around the Weldon Spring site as a result of exposures resulting from potential radioactive releases to the atmosphere during remediation of the chemicalplant area

Selection of the best proper DC-SQUIDs in a multi-SQUID configuration

We have carried out experimental investigation of multi-DC-SQUID magnetometer configuration fabricated on YBa2Cu30 7-δ thin films onto 24 degree SrTiO3 bicrystal substrates by directly coupling the pick-up loop to DC-SQUIDs. The layout of the magnetometer pick-up loop was chosen as a square washer configuration by maximizing loop effective area and minimizing loop inductance. We have used De-Magnetron Sputtering technique for deposition of the films and chemical etching process for patterning the Josephson junctions having 4 μm widths. The use of multi-SQUID configuration is related to the selection of the best proper junctions for SQUID to improve the chip sensitivity with selectivity option of choosing the squid junctions rather than multichannel operation. Selection of the best junctions compared to each other depending on the junction critical currents and noise levels caused by the fabrication process and placements of the junctions on the grain boundary enable having an increased output signal of the DC-SQUID. © 2007 IEEE

A textile platform using mechanically reinforced hydrogel fibres towards engineering tendon niche

INTRODUCTION: Tendon injuries can result from tendon overuse or trauma, resulting in substantial pain and disability. Given that natural or surgical repair of tendons lead to a poor outcome in terms of mechanical properties and functionality, there is a great need for tissue engineering strategies. Textile platforms enable the generation of biomimetic constructs [1]. Therefore, the main goal of this study is the development of cell-laden hybrid hydrogel fibers reinforced with a mechanically robust core fiber and their assembly into braided constructs towards replicating tendon mechanical properties and architecture. METHODS: To fabricate mechanically reinforced hydrogel fibres, a commercially available suture was coated using a cell-hydrogel mixture of methacryloyl gelatine (GelMA) and alginate. Composite fibres (CFs) were obtained by ionic crosslinking of alginate followed by photocrosslinking of GelMA. CFs were assembled using braiding technique and the mechanical properties of single fibres and braided constructs were evaluated. Different cells were encapsulated in the hydrogel layer, including MC-3T3, mesenchymal stem cells (MSCs) and human tendon-derived cells (TDCs). Cell viability and metabolic activity were evaluated by LIVE/DEAD staining and presto blue assay of metabolic activity. The expression of tendon-related markers and matrix deposition were also investigated. RESULTS: CFs were fabricated with a GelMA:alginate hydrogel layer and using multifilament twisted cotton or biodegradable suturing threads. The biocompatibility of this system was evaluated on encapsulated cells (Fig.1a). Cells (MC-3T3, MSCs and TDCs) were homogeneously distributed along the hydrogel layer, being viable up to 14 days in culture. In addition, TDCs were spreading inside the hydrogel after less than 48 h. Moreover, to further improve the mechanical properties of CFs, braided constructs were generated (Fig. 1b). Braiding CFs together enhanced their tensile strength and the process did not affect the viability of encapsulated cells.DISCUSSION & CONCLUSIONS: CFs were generated with a load bearing core and a hydrogel layer towards mimicking both mechanical properties and the matrix-rich microenvironment of tendon tissue. Accordingly, cell behaviour can be further modulated by modifying the hydrogel composition or, ultimately, through the addition of bioactive cues. Finally, braiding CFs together allows tuning the mechanical properties of developed constructs to match those of native tendon tissues.Fundação para a Ciência e a Tecnologia in the framework of FCT-POPH-FSE, the PhD grant SFRH/BD/96593/2013 of R.C-

Machine learning based prediction of squamous cell carcinoma in ex vivo confocal laser scanning microscopy

Image classification with convolutional neural networks (CNN) offers an unprecedented opportunity to medical imaging. Regulatory agencies in the USA and Europe have already cleared numerous deep learning/machine learning based medical devices and algorithms. While the field of radiology is on the forefront of artificial intelligence (AI) revolution, conventional pathology, which commonly relies on examination of tissue samples on a glass slide, is falling behind in leveraging this technology. On the other hand, ex vivo confocal laser scanning microscopy (ex vivo CLSM), owing to its digital workflow features, has a high potential to benefit from integrating AI tools into the assessment and decision-making process. Aim of this work was to explore a preliminary application of CNN in digitally stained ex vivo CLSM images of cutaneous squamous cell carcinoma (cSCC) for automated detection of tumor tissue. Thirty-four freshly excised tissue samples were prospectively collected and examined immediately after resection. After the histologically confirmed ex vivo CLSM diagnosis, the tumor tissue was annotated for segmentation by experts, in order to train the MobileNet CNN. The model was then trained and evaluated using cross validation. The overall sensitivity and specificity of the deep neural network for detecting cSCC and tumor free areas on ex vivo CLSM slides compared to expert evaluation were 0.76 and 0.91, respectively. The area under the ROC curve was equal to 0.90 and the area under the precision-recall curve was 0.85. The results demonstrate a high potential of deep learning models to detect cSCC regions on digitally stained ex vivo CLSM slides and to distinguish them from tumor-free skin

Dependence of Josephson junction critical current on the deposition rate of YBa2Cu3O7-δ thin films

We have reported the effect of YBa2Cu3O 7-δ (YBCO) thin film deposition rate on the 24 and 30 degree STO bicrystal Josephson junctions critical currents by fabricating series of junctions with different deposition rates. Dependence of YBCO thin film structures on the deposition rate was investigated. We have observed that the critical currents of junctions are strongly affected by the thin film deposition rate. © 2007 American Institute of Physics

The superconducting transition width and illumination wavelength dependence of the response of MgO substrate YBCO transition edge bolometers

Dependence of the phase and magnitude of the response of MgO substrate YBa2Cu3O7-δ (YBCO) transition edge bolometers to the near infrared radiation on the superconducting transition width is presented in this work. The bolometers were made of YBCO thin films of 200 nm thickness that were grown on single crystal MgO (1 0 0) substrates by DC inverted cylindrical magnetron sputtering. We have measured the responses of both large and small area devices with respect to the bias temperature and radiation modulation frequency. We have observed that the superconducting transition width has major effects on the response of the bolometers such as; on a dip of the phase of the response versus modulation frequency curve around 1 Hz, the rate of decrease of the magnitude of the response, and dependence of the phase of the response on temperature at mid-range modulation frequency. We have investigated a correlation between the superconducting transition width and the YBCO film surface morphology of the devices. In addition, the illumination wavelength dependence of the optical response of both wide and narrow transition width devices has been investigated. Here we present the analysis and the possible mechanisms that can affect the response of the bolometers at the superconducting transition region. © 2007 Elsevier B.V. All rights reserved

Stochastic description of infiltration between aquifers

Aim of this work is to propose a stochastic description of the leakage between two aquifers separated by a semi-permeable layer with low hydraulic conductivity. The source of uncertainty here considered is the random fluctuation of the phreatic surface of surficial aquifer, originated from random rainfall events. The study focuses on an area surrounding a pumping well penetrating the deep aquifer and impacting its piezometric level, where infiltration from the surficial aquifer can be more harmful. Closed form expressions for the leakage between the surficial and the deep aquifer are used to obtain the long-term probability distribution of leakage flow rate, assuming the shallow phreatic surface dynamics modeled with a Poisson- driven stochastic process. A sensitivity analysis is performed to verify the variability of the probability distribution of leakage within the range of feasible parameter values, then the stochastic model is applied to three field cases where time series of the piezometric levels of the phreatic aquifer are available. Results show that the induced variability of the discharge flowing between aquifers is remarkable and that in general it cannot be neglected despite the low hydraulic conductivity of the semi-permeable layer. The proposed probabilistic model is a useful tool for evaluating the risk associated to contaminant transport into deep aquifers and its fate in relation to groundwater withdrawal