bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nickel‐cobalt‐zinc ferrite nanoparticles for radio‐frequency/terahertz frequency‐selective surface application
Authors: Arya Meenakshi , Gandhi Mayuri N. , Prabhu Shriganesh S. , Achanta Venu Gopal , Duttagupta Siddhartha P 
Published: February 2021

AbstractNanoparticles of Ni0.5Co0.2Zn0.3Fe2O4 were prepared using the sol‐gel combustion route. The nanoparticles were characterised by x‐ray diffraction to confirm single‐phase formation in a cubic spinel structure. Micro‐ and nanostructural analyses were carried out using field emission‐scanning electron microscopy and field emission‐transmission electron microscopy, respectively. A planetary ball milling technique was used to grind the powder into nanoparticles; the average particle size was 64 nm. Energy‐dispersive X‐ray spectroscopy was used to determine the atomic composition of the sample. Radio‐frequency characteristics were recorded for dielectric measurement in a frequency range of 1 Hz to 15 MHz using a broadband dielectric spectrometer. Terahertz (THz) time‐domain spectroscopy was performed to study THz‐optical parameters such as refractive index, dielectric constant, and conductivity at room temperature in a frequency range of 0.3−2.2 THz using an indigenously developed THz time‐domain spectroscopy setup. The magnetic properties of the sample were studied using a SQUID vibrating sample magnetometer under an applied magnetic field of ±10 kOe. An examination of M‐H loops revealed that the saturation magnetization , remanent magnetization and coercivity increased with an increase in temperature from 300 to 50 K.
RECONSTRUCTING THE AXIAL VOID VELOCITY PROFILE IN BWRs FROM MEASUREMENTS OF THE IN-CORE NEUTRON NOISE
Authors: Pázsit Imre , Hursin Mathieu , Nylén Henrik , Dykin Victor 
Published: February 2021

The problem of determining the axial velocity profile from the in-core neutron noise measurements is revisited, with the purpose of developing an objective method for the determination of the void fraction. Until now it was assumed that in order to determine a realistic velocity profile which shows an inflection point and hence has to be at least a third order polynomial, one needs four transit times and hence five in-core detectors at various axial elevations. However, attempts to determine a fourth transit time by adding a TIP detector to the existing four LPRMs and cross-correlate it with any of the LPRMs were unsuccessful so far. In this paper we thus propose another approach, where the TIP detector is only used for the determination of the axial position of the onset of boiling.
By this approach it is sufficient to use only three transit times. Moreover, with another parametrisation of the velocity profile, it is possible to reconstruct the velocity profile even without knowing the onset point of boiling, in which case the TIP is not needed. In the paper the principles are explained and the strategy is demonstrated by concrete examples.
APPLICATION OF CALCULATED MSM FACTORS USING TRIPOLI4® SEQUENCE ON BORON LINED PROPORTIONAL COUNTER ROD WORTH MEASUREMENT
Authors: Couybes J. , Nicolas S. , Chabert L. , Manifacier L. , Barbosa T. , Gerlier R. 
Published: February 2021

The topic addressed deals with the determination of adjoint parameters for instrumentation relevance. This is a crucial subject for comprehension of subcritical levels in the frame of safety analysis. Indeed, such states require interpretation and raw data cannot be processed as such. To do so, the transcription of core reactivity through instrumentation located in the reactor periphery is considered with the use of MSM factors [1],[2]. We implement this method inside a TRIPOLI4® [3] sequence in order to establish predictive mapping of MSM factors and figure out optimal position for instrumentation location at the beginning of reactor operations.
Firstly, MSM factors are introduced, along with the designer point of view for geometry construction based on ROOT package [4]. At this point, the methodology of TRIPOLI4® calculation is explained in detail, including the sequencing associated to and how the Green Functions are performed within TRIPOLI4®.
In this second part and within the verification framework, the previous method is extended to a “fictitious core” developed in TechnicAtome for Monte Carlo [5] calculation and for different core pattern loadings. After the completion of these numerical validations gained on a High Performing Cluster, the method is then expanded to critical mock up [6] and challenged to recent experimental results for validation. The comparisons end up with a good agreement between predictive calculation and experimental values of reactivity worth.
Finally the document ends with a mid-term projection for outlooks and improvements, for ensuring an enhancement of the safety approach. Several items are discussed especially, fine tuning for the spatial meshing (regarding instrumentation size) and the impact on TRIPOLI4® Monte Carlo code with the development of new features. Then, the authors focus on sensitivity effect concerning delayed neutron spectrum and kinetics parameters. As a conclusion, this paper proposes to validate the method exposed in the near future, using experimental data coming from many years of critical mock up operations.
IMPROVING A POSTERIORI SPATIAL DISCRETIZATION ERROR ESTIMATION FOR SN TRANSPORT BY SINGULAR CHARACTERISTICS TRACKING
Authors: Hart Nathan H. , Azmy Yousry Y. 
Published: February 2021

Previously, we have developed a novel spatial discretization error estimator, the “residual source” estimator, in which an error transport problem, analogous to the discretized transport equation, is solved to acquire an estimate of the error, with a residual term acting as a fixed source. Like all error estimators, the residual source estimator suffers inaccuracy and imprecision in the proximity of singular characteristics, lines across which the solution is irregular. Estimator performance worsens as the irregularities become more pronounced, especially so if the true solution itself is discontinuous.
This work introduces a modification to the residual approximation procedure that seeks to reduce the adverse effects of the singular characteristics on the error estimate. A partial singular characteristic tracking scheme is implemented to reduce the portion of the error in the numerical solution born by irregularities in the true solution. This treated numerical solution informs the residual approximations.
The partial singular characteristic tracking scheme greatly enhances the numerical solution for a problem with prominent singular characteristics. The residual approximation and resultant residual source error estimate are likewise improved by the scheme, which only incurs the computational cost of an extra inner iteration.
TOWARDS CAD-BASED GEOMETRY MODELLING WITH THE RANDOM RAY METHOD
Authors: Shriwise Patrick C. , Tramm John R. , Davis Andrew , Romano Paul K. 
Published: February 2021

The Advanced Random Ray Code (ARRC) is a high performance computing application capable of high-fidelity simulations of full core nuclear reactor models. ARRC leverages a recently developed stochastic method for neutron transport, known as The Random Ray Method (TRRM), which offers a variety of computational and numerical advantages as compared to existing methods. In particular, TRRM has been shown to be capable of efficient simulation of explicit three dimensional geometry representations without assumptions about axial homogeneity. To date, ARRC has utilized Constructive Solid Geometry (CSG) combined with a nested lattice geometry which works well for typical pressurized water reactors, but is not performant for the general case featuring arbitrary geometries.
To facilitate simulation of arbitrarily complex geometries in ARRC efficiently, we propose performing transport directly on Computer-Aided Design (CAD) models of the geometry. In this study, we utilize the Direct-Accelerated Geometry Monte Carlo (DAGMC) toolkit which tracks particles on tessellated CAD geometries using a bounding volume hierarchy to accelerate the process, as a replacement for ARRC’s current lattice-based accelerations. Additionally, we present a method for automatically subdividing the large CAD regions in the DAGMC model into smaller mesh cells required by random ray to achieve high accuracy. We test the new DAGMC geometry implementation in ARRC on several test problems, including a 3D pincells, 3D assemblies, and an axial section of the Advanced Test Reactor. We show that DAGMC allows for simulation of complex geometries in ARRC that would otherwise not be possible using the traditional approach while maintaining solution accuracy.
DEVELOPMENT OF A COUPLED SUBPLANE CAPABILITY IN MPACT
Authors: Stimpson Shane , Graham Aaron , Collins Benjamin 
Published: February 2021

Recent efforts in the development of the deterministic transport code MPACT have been devoted to preparing the 2D/1D subplane method to be a production-level capability, as well as leveraging a multilevel coarse mesh finite difference (CMFD) approach to substantially reduce the runtime of target problems. For example, as compared to the previous default 2D/1D solver in MPACT on a standard quarter core model, the new solver reduces in core-hour requirements by ~5–6×.
Previous work focused solely on cases without multiphysics feedback, which is obviously important for analyzing the more realistic problems of operating reactors. The work presented in this article focuses on efforts to incorporate thermal hydraulics (TH) coupling through CTF by leveraging what are termed as subgrid solvers, which effectively treat material heterogeneities within subplane regions. Previous efforts have targeted using subgrid solvers for control rods and spacer grids; in this work, they are applied to account for the material property heterogeneities with regards to temperature/density distributions. This will allow the fidelity of coupling to be maintained while still reaping the performance benefits.
These new developments are demonstrated on two problems: (1) a single assembly case with feedback, known as Progression Problem 6a, and (2) a 3×3 cluster of assemblies with feedback based on Progression Problem 4a. The results demonstrate notable performance improvement potential for cases with TH feedback, but this approach is more dependent on the iteration process.
REDUCED-ORDER MODELLING OF PARAMETERIZED TRANSIENT FLOWS IN CLOSED-LOOP SYSTEMS
Authors: German Péter , Tano Mauricio , Ragusa Jean C. , Fiorina Carlo 
Published: February 2021

In this paper, two Galerkin projection based reduced basis approaches are investigated for the reduced-order modeling of parameterized incompressible Navier-Stokes equations for laminar transient flows. The first approach solves only the reduced momentum equation with additional, physics-based approximations for the dynamics of the pressure field. On the other hand, the second approach solves both the reduced momentum and continuity equations. The reduced bases for the velocity and pressure fields are generated using the method of snapshots combined with Proper Orthogonal Decomposition (POD) for data compression. To remedy the stability issues of the two-equation model, the reduced basis of the velocity is enriched with supremizer functions. Both reduced-order modeling approaches have been implemented in GeN-Foam, an OpenFOAM-based multi-physics solver. A numerical example is presented using a two-dimensional axisymmetric model of the Molten Salt Fast Reactor (MSFR) and the dynamic viscosity as the uncertain parameter.
The results indicate that the one-equation model is slightly more accurate in terms of velocity, while the two-equation model, built with the same amount of modes for the velocity, is far more accurate in terms of pressure. The speed-up factors for the reduced-order models are 3060 for the one-equation model and 2410 for the two-equation model.
DIAGNOSIS OF THE UNRESOLVED DOMAIN TREATMENT IN MONTE CARLO TRANSPORT CALCULATIONS THROUGH THE IDENTIFICATION AND MODELLING OF CRITICALITY SAFETY EXPERIMENTS
Authors: García-Herranz N. , Rodríguez J. , Jiménez-Carrascosa A. , Cabellos O. 
Published: February 2021

Monte Carlo neutron transport codes can be used for high-fidelity predictions of the performance of nuclear systems. However, validation against experiments is required in order to establish the credibility in the results and identify the inaccuracies due to the used calculation scheme and associated databases. The International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP) contains criticality safety benchmarks derived from experiments that have been performed at various nuclear critical facilities around the world and are very valuable for validation purposes.The main objective of this work is the identification and modelling of experimental benchmarks included at ICSBEP in support of the validation of Monte Carlo neutron transport calculations when applied to fast systems, and in particular, KENO-VI and associated AMPX-formatted continuous-energy libraries from SCALE package. In such systems, the predicted k-eff values can be very sensitive to the treatment of nuclear data in the Unresolved Resonance Region (URR). Consequently, benchmarks with intermediate and fast spectra are identified and modelled with KENO-VI. Then, calculated results with and without probability tables in the URR are compared with each other in order to identify the most sensitive configurations to the URR. As a result of the proposed study, recommendations are given about the benchmarks that should be modelled and analysed to qualify the processed continuous-energy libraries before their use in Monte Carlo transport codes for practical fast reactor applications.
CONSOLIDATION OF REACTOR PHYSICS EDUCATION – THE KHALIFA UNIVERSITY STUDENT FIELD TRIPS CASE STUDY
Authors: Alameri Saeed A. , Alrwashdeh Mohammad , Beeley Philip , Kim Myung-Hyun , Unlu Kenan 
Published: February 2021

In 2010, the Department of Nuclear Engineering at Khalifa University of Science and Technology (NUCE) established the MSc degree in Nuclear Engineering. This program was established to support the United Arab Emirates (UAE) emerging civil nuclear energy program and produce graduate engineers capable of supporting the safe construction, operation, maintenance and eventual decommissioning of the UAE nuclear reactors. In order to enhance and consolidate classroom teaching, an overseas “Field Trip” module was integrated into the MSc curriculum in order to provide practical exercises, demonstrations and site visits. With respect to the consolidation of reactor physics teaching in particular, the field trips over the past 9 years have utilized mainly the AGN Zero Power reactor at Kyung Hee University (2012-2015) and the Breazeale TRIGA reactor at Penn State University (2017-2018). In both cases students gained “hands-on” supervised experience in classical reactor experiments, shielding measurements, health physics and radiological protection control, and radioanalytical measurement methods, such as neutron activation analysis. At Penn State University, the experiments were extended to surveillance measurements, taking advantage of the facilities specialized modules in nuclear security.
This paper provides details of the arrangements made for the field trips and the learning outcomes these practical arrangements helped to satisfy meeting the overall degree outcomes. The case study will also illustrate where a nuclear energy newcomer State can take advantage of international collaborations without the need to invest in a national research reactor.
Surgical Aspects in Gene Therapy for Inherited Retinal Diseases
Authors: Fischer M. Dominik , Bartz-Schmidt Karl Ulrich , Dimopoulos Spyridon , Herrmann Philipp , Gerhardt Maximilian , Holz Frank G. , Priglinger Siegfried 
Published: February 2021

AbstractInherited retinal dystrophies (IRD) have been studied since their recognition by Franz Donders and Albrecht von Graefe. It nevertheless took 100 years for a causal therapy to take shape in the form of gene therapy: The approval of Voretigen Neparvovec (VN) for the treatment of hereditary retinal dystrophies due to RPE65 mutations was thus a significant milestone – for the era of personalised medicine in general and ophthalmology in particular. The clinical management around gene therapy applications is complex and requires the cooperation of various experts as a multidisciplinary team. This article describes the requirements, challenges, approaches, and open questions regarding the surgical aspects of gene therapy for retinal dystrophies. The first part outlines the standard surgical treatment. Based on this standard, alternative approaches are indicated for each individual step and their value discussed. Knowledge gaps are defined and in the outlook we speculate
on future developments.
Predicting the Relapse of Hyperthyroidism in Treated Graves’ Disease with Orbitopathy by Serial Measurements of TSH-Receptor Autoantibodies
Authors: Stöhr Mareile , Oeverhaus Michael , Lytton Simon D. , Horstmann Mareike , Zwanziger Denise , Möller Lars , Stark Achim , Führer-Sakel Dagmar , Bechrakis Nikolaos , Berchner-Pfannschmidt Utta , Banga J. Paul , Philipp Svenja , Eckstein Anja 
Published: February 2021

AbstractThe aim of this study was to investigate the potential of the new TSH-receptor antibody (TRAb) assays to predict remission or relapse of hyperthyroidism in patients with Graves’ disease (GD) and Graves’ orbitopathy (GO). TRAbs were measured retrospectively in sera from a cohort of GD patients with GO (n=117; remission n=38 and relapse n=79–Essen GO biobank) with automated binding immunoassays: TRAb Elecsys (Cobas Roche) and TRAb bridge assay (IMMULITE, Siemens), and the TSAb (thyroid stimulating Ab) cell-based bioassay (Thyretain, Quidel Corp.). To identify relapse risk/remission of hyperthyroidism patients were followed up at least 10 months after the end of antithyroid drug therapy (ATD) therapy. ROC plot analysis was performed to calculate cut-off levels of TRAb and TSAb for prediction of relapse and remission of hyperthyroidism. Cut-off serum levels are provided for timepoints around 3, 6, 10, and 15 months after the beginning of ATD. Repeated measurements of TRAb increase the rate of relapses predictions to 60% (Elecsys), 70% (IMMULITE), and 55% (Thyretain). Patients with remission have consistently TRAb levels below the cut off for relapse in repeated measurements. The cell-based bioassay was the most sensitive – and continued to be positive during follow up [at 15 months: 90% vs. 70% (IMMULITE) and 65% (Elecsys)]. Identification of relapsing hyperthyroidism is possible with automated immunoassays and cell-based bioassay especially with serial TRAb measurements during the course of ATD therapy. Patient who need eye surgery may profit from an early decision towards definitive treatment.
Custom-Made Pyrene Photocatalyst-Promoted Desulfonylation of Arylethenyl Sulfones Using Green-Light-Emitting Diodes
Authors: Orita Akihiro , Watanabe Hikaru , Nakajima Kazuki , Ekuni Kento , Edagawa Ryota , Akagi Yuta , Okuda Yasuhiro , Wakamatsu Kan 
Published: February 2021

AbstractThe Sonogashira coupling of 1,3,6,8-tetrabromopyrene with 4-[(–)-β-citronellyloxy]phenylethyne was employed to synthesize 1,3,6,8-tetra[4-(citronellyloxy)phenylethynyl]pyrene. The pyrene derivative catalyzed the reductive desulfonylation of ethenyl sulfones via visible-light irradiation (514 nm green light-emitting diodes) in the presence of i-Pr2NEt. The β-citronellyloxy groups provided the sufficient solubility to the highly π-expanded pyrene catalyst, and their polar oxygen functionalities enabled the easy separation of the catalyst from the products via column chromatography.
The Accuracy of Direct Targeting Using Fusion of MR and CT Imaging for Deep Brain Stimulation of the Subthalamic Nucleus in Patients with Parkinson's Disease
Authors: Almahariq Fadi , Sedmak Goran , Vuletić Vladimira , Dlaka Domagoj , Orešković Darko , Marčinković Petar , Raguž Marina , Chudy Darko 
Published: February 2021

Abstract
Introduction In 33 consecutive patients with Parkinson's disease (PD) undergoing awake deep brain stimulation (DBS) without microelectrode recording (MER), we assessed and validated the precision and accuracy of direct targeting of the subthalamic nucleus (STN) using preoperative magnetic resonance imaging (MRI) and stereotactic computed tomography (CT) image fusion combined with immediate postoperative stereotactic CT and postoperative MRI, and we report on the side effects and clinical results up to 6 months' follow-up.
Materials and Methods Preoperative nonstereotactic MRI and stereotactic CT images were merged and used for planning the trajectory and final lead position. Immediate postoperative stereotactic CT and postoperative nonstereotactic MRI provided the validation of the final electrode position. Changes in the Unified Parkinson's Disease Rating Scale III (UPDRS III) scores and the levodopa equivalent daily doses (LEDD) and appearance of adverse side effects were assessed.
Results The mean Euclidian distance (ED) error between the planned position and the final position of the lead in the left STN was 1.69 ± 0.82 mm and that in the right STN was 2.12 ± 1.00. The individual differences between planned and final position in each of the three coordinates were less than 2 mm. The UPDRS III scores improved by 75% and LEDD decreased by 45%. Few patients experienced complications, such as postoperative infection (n = 1), or unwanted side effects, such as emotional instability (n = 1).
Conclusion Our results confirm that direct targeting of an STN on stereotactic CT merged with MRI could be a valid method for placement the DBS electrode. The magnitude of our targeting error is comparable with the reported errors when using MER and other direct targeting approaches.
TIA1 potentiates tau phase separation and promotes generation of toxic oligomeric tau
Authors: Ash Peter E. A. , Lei Shuwen , Shattuck Jenifer , Boudeau Samantha , Carlomagno Yari , Medalla Maria , Mashimo Bryce L. , Socorro Guillermo , Al-Mohanna Louloua F. A. , Jiang Lulu , Öztürk Muhammet M. , Knobel Mark , Ivanov Pavel , Petrucelli Leonard , Wegmann Susanne , Kanaan Nicholas M. , Wolozin Benjamin 
Published: February 2021

Significance
Phase separation of proteins is increasingly thought to play a fundamental role in biological processes. Recent studies show that tau protein phase separates, but the biological significance is unknown since artificial crowding agents are typically used and the resulting tau is not toxic. We now demonstrate that TIA1 potentiates RNA-mediated phase separation of tau, thereby enabling a process that occurs at physiological concentrations and also directs the formation of biologically active, highly neurotoxic oligomeric tau. Coordinated phase separation of functionally related proteins provides a general mechanism through which membraneless organelles can direct biological activities.
Bromodomain proteins regulate human cytomegalovirus latency and reactivation allowing epigenetic therapeutic intervention
Authors: Groves Ian J. , Jackson Sarah E. , Poole Emma L. , Nachshon Aharon , Rozman Batsheva , Schwartz Michal , Prinjha Rab K. , Tough David F. , Sinclair John H. , Wills Mark R. 
Published: February 2021

SignificanceHuman cytomegalovirus (HCMV) reactivation is a major cause of posttransplant morbidity/mortality. One approach toward reducing this is purging the transplant donor and/or recipient of latently infected cells prior to stem-cell or organ harvest/engraftment. Our findings show the involvement of host bromodomain (BRD) proteins in regulation of HCMV latency and reactivation. Bromodomain and extra-terminal inhibitor (I-BET) treatment of latently infected cells causes reactivation of lytic gene expression by release of transcription activator P-TEFb (CDK9/CycT1) from BRD4-associated repressive complexes, with subsequent recruitment via host superelongation complex (SEC). This results in immune targeting and T cell-mediated killing of these otherwise latently infected cells and provides a therapeutic “shock and kill” strategy that could reduce HCMV-mediated disease in the transplant setting.