An anisotropic numerical model for thermal hydraulic analyses: application to liquid metal flow in fuel assemblies

A CFD analysis has been carried out to study the thermal–hydraulic behavior of liquid metal coolant in a fuel assembly of triangular lattice. In order to obtain fast and accurate results, the isotropic two-equation RANS approach is often used in nuclear engineering applications. A different approach is provided by Non-Linear Eddy Viscosity Models (NLEVM), which try to take into account anisotropic effects by a nonlinear formulation of the Reynolds stress tensor. This approach is very promising, as it results in a very good numerical behavior and in a potentially better fluid flow description than classical isotropic models. An Anisotropic Shear Stress Transport (ASST) model, implemented into a commercial software, has been applied in previous studies, showing very trustful results for a large variety of flows and applications. In the paper, the ASST model has been used to perform an analysis of the fluid flow inside the fuel assembly of the ALFRED lead cooled fast reactor. Then, a comparison between the results of wall-resolved conjugated heat transfer computations and the results of a decoupled analysis using a suitable thermal wall-function previously implemented into the solver has been performed and presented

Integrating immune checkpoint blockade with anti-neo/mutated antigens reactivity to increase the clinical outcome of immunotherapy

Antibodies to immune checkpoints have entered the clinical arena and have been shown to provide a clinical benefit for metastatic melanoma and, possibly, for other tumors as well. In this review paper we summarize this therapeutic activity and underline the functional mechanisms that may be involved. Among them, we discuss the so far neglected role of tumor-associated antigens (TAAs) deriving from tumor somatic mutations and summarize the results of recent trials showing the immunogenic strength of such TAAs which can be specifically targeted by T cells activated by immune checkpoint antibodies. Finally we discuss new immunotherapy approaches that involve the combination of self/shared- or neo-TAAs-based vaccines and immune checkpoint blockade antibodies, to increase the clinical response of metastatic melanoma patients

A multi-family GLRT for detection in polarimetric SAR images

This paper deals with detection from multipolarization SAR images. The problem is cast in terms of a composite hypothesis test aimed at discriminating between the Polarimetric Covariance Matrix (PCM) equality (absence of target in the tested region) and the situation where the region under test exhibits a PCM with at least an ordered eigenvalue smaller than that of a reference covariance. This last setup reflects the physical condition where the back scattering associated with the target leads to a signal, in some eigen-directions, weaker than the one gathered from a reference area where it is apriori known the absence of targets. A Multi-family Generalized Likelihood Ratio Test (MGLRT) approach is pursued to come up with an adaptive detector ensuring the Constant False Alarm Rate (CFAR) property. At the analysis stage, the behaviour of the new architecture is investigated in comparison with a benchmark (but non-implementable) and some other adaptive sub-optimum detectors available in open literature. The study, conducted in the presence of both simulated and real data, confirms the practical effectiveness of the new approach

Knowledge Rich Natural Language Queries over Structured Biological Databases

Increasingly, keyword, natural language and NoSQL queries are being used for information retrieval from traditional as well as non-traditional databases such as web, document, image, GIS, legal, and health databases. While their popularity are undeniable for obvious reasons, their engineering is far from simple. In most part, semantics and intent preserving mapping of a well understood natural language query expressed over a structured database schema to a structured query language is still a difficult task, and research to tame the complexity is intense. In this paper, we propose a multi-level knowledge-based middleware to facilitate such mappings that separate the conceptual level from the physical level. We augment these multi-level abstractions with a concept reasoner and a query strategy engine to dynamically link arbitrary natural language querying to well defined structured queries. We demonstrate the feasibility of our approach by presenting a Datalog based prototype system, called BioSmart, that can compute responses to arbitrary natural language queries over arbitrary databases once a syntactic classification of the natural language query is made

Conceptual design of the enhanced coolant purification systems for the European HCLL and HCPB test blanket modules

The Coolant Purification Systems (CPSs) is one of the most relevant ancillary systems of European Helium Cooled Lead Lithium (HCLL) and Helium Cooled Pebble Bed (HCPB) Test Blanket Modules (TBMs) which are currently in the preliminary design phase in view of their installation and operation in ITER. The CPS implements mainly two functions: the extraction and concentration of the tritium permeated from the TBM modules into the primary cooling circuit and the chemistry control of helium primary coolant. During the HCLL and HCPB-TBSs (Test Blanket Systems) Conceptual Design Review (CDR) in 2015 it was recognized the need of reducing the tritium permeation into the Port Cell #16 of ITER. To achieve this and, then, to lower the tritium partial pressure in the Helium Cooling Systems in normal operation, the helium flow-rate treated by each CPS has been increased of almost one order of magnitude. In 2017, to satisfy the CDR outcomes and the new design requirements requested by Fusion for Energy (F4E, the European Domestic Agency for ITER), ENEA performed a preliminary design of the “enhanced” CPSs. This paper presents the current design of the “enhanced” CPSs, focusing on design requirements, assumptions, selection of technologies and preliminary components sizing

Fall risk assessment in elderly with and without history of falls: kinematic gait analysis: a comparative study

Objectives: The objective of this research was to verify if there was a variation in the MFC (Minimum Foot Clearance) value among elderly with and without history of falls and, if there were any, verify which joint of the lower limb was responsible for that variation. It was also a main objective to verify if there was a correlation between the risk of falling, achieved through the Timed Up and Go Test (TUG), and the MFC variation. Material and Methods: The sample consisted of a total of 30 elderly who met the inclusion and exclusion criteria. These were divided into the group without history of falls (n=15) and into the group with history of falls (n=15). The MFC and the joint movement amplitudes of the hip, knee and ankle, of the dominant lower limb, were assessed using the Kinovea programme and for the risk of fall assessment it was used the TUG. Results: There were no statistically significant differences in the MFC and TUG values between the groups with and without history of falls. However, there is a decrease of the MFC value for the group with history of falls, being the ankle the joint that most contributed to the MFC variation in the group without history of falls, and the knee in the group with history of falls. About the relation between MFC and TUG, it was obtained a negative correlation (r=-0,269) but it was not significant (p=0,150). Conclusion: In our sample no significant differences in the MFC value were obtained between the group with history of falls and the group without history of falls. Besides the lack of significant differences in the MFC value it was determined the articulation of the lower limb responsible for its variation, and it has been found, although with a p>0,05, that for the group with no history of falls it was the ankle that more contributed to this variation and the knee to the group with history of falls. Concerning to the TUG and MFC value correlation it wasn’t significant. Thus, it was concluded that the TUG use is more effective and sensitive in predicting the risk of falling when compared with the kinematic analysis to obtain the MFC value and the joints amplitude

Fall risk assessment in elderly with and without history of falls: relationship between disorders of balance, fear of falling and gait changes: a comparative study

Objectives: The aim of this study was to assess the changes that occur in the balance, fear of falling and kinematic parameters such as stride length, velocity and time support in elderly with and without a history of falling. Main objective was also to verify whether a relationship exists between changes in gait parameters evaluated, balance and fear of falling. Methods: The sample comprised 30 patients (15 with history of falls and 15 without a history of falls), which met the criteria for inclusion and exclusion. The kinematic evaluation was performed in the dominant leg, which was right in this sample. The stride length, speed and duration of support were assessed using the program Kinovea and for assessment of balance and fear of falling were assessed using the Berg Balance Scale and the Falls Efficacy Scale. Statistical analysis was performed with SPSS version 20. Results: There were no significant differences in the parameters analyzed, except for scores on the Berg Balance Scale (p=0.000) between groups with and without history of falls. However, there is a decrease in the length of the stride and duration of left leg support and the increased length of right leg support, the speed and the fear of falling. The relationship between the parameters obtained, there is only statistically significant result between speed and stride length (r=0.507, p=0.004) and between the score of the Berg Balance Scale and the stride length (r=0.393, p=0,032). Conclusion: Although not having obtained statistically significant results we can conclude that in elderly with a history of falls have changes in speed and stride length that can be related to balance disorders and the aging process itself. However, it is concluded that the use of the Berg Balance Scale is more responsive and effective in the detection of changes occurring in the individual after a fall, and subsequent evaluation of the risk of falling that performing a kinematic analysis

Fall risk assessment in elderly with and without history of falls: strength analysis of lower limb: a comparative study

Objectives: The objective of this research was to analyse muscle performance criteria of the knee joints and ankle flexor and extensor muscles among elderly with and without history of falls. Material and methods: The sample was non-probabilistic, of convenience, comprising a total of 30 elderly (15 with history of falls and 15 without history of falls) who met the inclusion and exclusion criteria. Data were collected through a characterization questionnaire and through the Biodex System Isokinetic Dynamometer. The isokinetic assessment consisted in collecting the Peak Torque per unit of mass (N.m/BW) and ratio FlexorsCon/ExtensorsCon (%) of the knee joints and ankle flexor and extensor muscles, with 5 repetitions and the 60º/s angular speed. This collection has been made in both lower limbs. Results: The sample consisted of 30 individuals, 15 from the group without history of falls and 15 from the group with history of falls with average age of (69,17±4,77) years old. The muscle performance parameters were not significantly different between the groups (p>0,05). Conclusion: The group of elderly with history of falls showed lower Peak Torque numbers per unit of mass (N.m/BW) for the knee and ankle joint comparing with the group without history of falls. In present research also the values of the ratio flexorsCon/ExtensorsCon was analyzed weren't differences found in the knee and ankle joint. Although there are no statistically significant differences between results obtained, approach we believe it will be beneficial to include strengthening exercises for the flexors and extensors muscles of these joints, thereby contributing to the prevention of falls