bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Activity for the Investigation of Mixing and Thermal Stratification Phenomena in the CIRCE Pool Facility
Authors: Martelli D. , Tarantino M. , Di Piazza I. 
Published: October 2016

Since the Lead-cooled Fast Reactor (LFR) has been conceptualized in the frame of GEN IV International Forum (GIF), ENEA is strongly involved in the HLM technology development.
In particular, several experimental campaign employing HLM loop and pool facilities (CIRCE [1], NACIE [2], HELENA [3], HERO [4]) are carried out in order to support HLM technologies development.
In this frame, suitable experiments were carried out on the CIRCE pool facility refurbished with the Integral Circulation Experiment (ICE) test section in order to investigate the thermal hydraulics and the heat transfer in grid spaced Fuel Pin Bundle cooled by liquid metal providing, among the others aim, experimental data in support of codes validation for the European fast reactor development.
The study of thermal stratification in large pool reactor is relevant in the design of HLM nuclear reactor especially for safety issue. Thermal stratification should induce thermomechanical stresses on the structures and in accidental scenario conditions, could opposes to the establishment of natural circulation which is a fundamental aspect for the achievements of safety goals required in the GEN-IV roadmap.
In the present work, a Protected Loss of Heat Sink with Loss Of Flow (PLOHS+LOF) scenario is experimentally simulated and the mixed convection with thermal stratification phenomena is investigated during the simulated transient, as foreseen in the frame of Horizon 2020 SESAME project [5].
A full characterization of thermal stratification inside the pool is presented, and the main results gained during the run are reported.
The two tests named A (20 h) and B (6 h) here reported, essentially differs for the power supplied to the fuel bundle during the full power run (800 kW and 600 kW respectively). After the transition to natural circulation conditions, the power supplied to the bundle is decreased to about 30 kW simulating the decay heat.
Finally the Nusselt number for the central subchannel of the fuel bundle simulator (FPS) is evaluated and compared with values obtained from Ushakov and Mikityuk correlations [6–7].
Investigation of Liquid Metal Embrittlement of AISI 316L Steels
Authors: Stefanini L. , Lo Frano Rosa , Stergar Erich 
Published: October 2016

To support the feasibility and the deployment of LFRs one of the main issues to be solved is the reliability of structural materials to be exposed to liquid metal coolant.
Particularly the Liquid Metal Embrittlement (LME) of steels is of interest for nuclear reactors and spallation sources projects because structural materials for these systems are selected according to their corrosion resistance, irradiation embrittlement and compatibility with the coolant.
This study was performed in the framework of MYRRHA project, a new-generation sub-critical reactor (based on the Accelerator Driving System concept) that uses Lead-Bismuth Eutectic (LBE) as coolant.
LME phenomenon has been investigated by performing theoretical and experimental activity profiting and basing on the results obtained for the T91 m/f steel in contact with LBE.
This paper first reviews the model of Kamdar: weak points and contradictions are highlighted.
From an experimental point of view to verify the occurrence of LME, Slow Strain Rate Tensile tests were performed on the AISI 316L in LBE environment at SCK-CEN laboratories.
Besides, a fracture surface analysis was carried out together with a microstructural analysis by using that Scanning Electron Microscopy. This was done in order to confirm the results obtained by the mechanical tests and to look for impurities in the metallic matrix. These impurities are an interesting feature in case of high scatter in the results.
Indeed one of the difficulties was the opacity and conductivity of the medium.
The methodological approach and the procedure are also duly described along with preliminary results.
Development of High Efficiency Containment Venting System by Using AgX
Authors: Narabayashi Tadashi , Sugano Yuuhei , Imaeda Hiroki , Chiba Go , Sato Nobuaki , Endo Koji , Kobayashi Toshiki 
Published: October 2016

Fukushima Daiichi NPP accident would be terminated, if sufficient accident countermeasures, such as water proof door, mobile power, etc [1, 2]. In case of Europe, it had already installed the heat removal system and filtered containment venting system (FCVS) from the lessons of TMI and Chernobyl Accidents. The new regulatory standard in Japan, the filtered vent system (FCVS) should be installed, and prevent the radioactive material in case of the severe accident and the overpressure breakage prevention of a primary containment vessel (PCV) and also the robustization of the FCVS.
The authors examined the severe accident process in the 2nd unit of Fukushima Daiichi NPS, and found the vent by FCVS should be done before water injection into the core. The PCV spray and water injection into the pedestal basement should be also the countermeasures to the severe accident. Countermeasures for an intentional aircraft collision should be installed too.
Upon occurrence of a severe accident (SA), vent gas with radioactive fission products is blown out to a scrubbing pool through numerous venturi nozzles. Mist in steam moves upward to a metal fiber filter through a multi-hole baffle plate. After the mist is removed by that filter, radioactive methyl iodine (CH3I) is captured on the surface of a molecular sieve or AgX, made from zeolite particles with silver coating.
A FCVS visualized test facility was installed at Hokkaido University. An AgX filter is used down-stream of the scrubbing pool and metal fiver filter. Thickness of AgX filter is very important parameter to obtain enough decontamination factor (DF). The DF for the radioactive iodine exceeds 10,000 at bed depth (AgX filter thickness) greater than 75mm.
Dynamic Simulation Studies of Performed Additional Tests During FAT for Emergency Diesel Generators at Nuclear Power Plant
Authors: Kanaan Salah K. , Omanovic Amer 
Published: October 2016

In 2004, a decision was made to perform a modernization and a new power uprate of unit 2 at Oskarshamn nuclear power plant in Sweden. Among the most important reasons for this decision were new safety regulations from Swedish Radiation Safety Authority and ageing of important components. A project was established and became the largest nuclear power modernization in the world.
The modernization led to the need of analysing the auxiliary power system to ensure that it could supply the unit after the uprate, given tolerances on current, voltage and frequency. During the process of developing models for the diesel generator sets, it turned out that the suppliers could not deliver enough satisfactory material for modelling the diesel engines, the speed controllers and the magnetization systems. Therefore, Oskarshamn nuclear power plant with the help of the manufacturers of the diesel generator sets carried out additional measurements in order to collect data for modelling.
Based on electric circuit diagrams provided by the manufacturers, block diagrams of the magnetization systems were made. For the speed controllers, no information was available at all so it was assumed that the controller was of PI-type. The parameters of the magnetization systems and the speed controllers were then tuned using the measurement results.
Finally, a comparison between simulated results and the measurement results were made, showing good agreement. This is especially true in the most commonly used operating interval of the diesel generator sets.
Evaluation of Sodium Pool Fire and Thermal Consequence in Two-Cell Configuration
Authors: Ohno Shuji , Takata Takashi , Tajima Yuji 
Published: October 2016

Evaluation of accidental sodium leak, combustion, and its thermal consequence is one of the important issues to be assessed in the field of sodium-cooled fast reactor (SFR) since the liquid sodium is chemically active and might give thermal load to plant building structure due to its exothermic reaction with oxygen in air atmosphere. Therefore, many experimental investigations and numerical simulation tools development have been and still now are being carried out to understand the details of sodium fire behaviors and to contribute to the investigation and preparation of appropriate mitigation measures in the plant design.
From various kinds of sodium fire situations, the present paper treats the sodium pool fire and subsequent heat transfer behavior in air atmosphere two-cell geometry both experimentally and analytically because such two-cell configuration is considered as the typical one to possess important characteristic of multi-compartment system seen in an actual plant. Main description of this paper consists of a sodium pool fire experiment that was performed in a rectangular-shaped two-cell system with an opening between the cells, and the discussion of the experimental results. Inner volume of the experimental cells is about 70 m3. The amount of used sodium and the prepared pool surface area in the experiment are about 55 kg and 2.25 m2, respectively. The experiment has provided the temperature data measured in more than 100 positions for atmospheric gas and structures other than the data of oxygen concentration and suspended sodium aerosols concentration in the cells. The analyses of the measured data clarify the basic characteristics of sodium pool combustion and consequential heat and mass transfer in the cells, for instance, suggesting several features of multidimensional thermal-hydraulic behaviors such as thermal stratification near the opening between the two cells. In the discussion, numerical analysis using a lumped-parameter based zonal model safety analysis code ‘SPHINCS’ and the comparison of its results with the experimental data are also carried out to investigate the validity and applicability of the code to this type of sodium fire situation.
Climate change: The 2015 Paris Agreement thresholds and Mediterranean basin ecosystems
Authors: Guiot Joel , Cramer Wolfgang 
Published: October 2016

A warming limit for the Mediterranean basin
Pollen cores from sediments provide rich detail on the history of vegetation and climate in the Mediterranean during the Holocene (the most recent ~10,000 years). Guiot and Cramer used this information as a baseline against which to compare predictions of future climate and vegetation under different climate-change scenarios. Vegetation and land-use systems observed in the Holocene records may persist under a 1.5°C warming above preindustrial temperature levels. A 2°C warming, however, is likely over the next century to produce ecosystems in the Mediterranean basin that have no analog in the past 10,000 years.

Science
, this issue p.
465
Molecular Bases Determining Daptomycin Resistance-Mediated Resensitization to β-Lactams (Seesaw Effect) in Methicillin-Resistant Staphylococcus aureus
Authors: Renzoni Adriana , Kelley William L. , Rosato Roberto R. , Martinez Maria P. , Roch Melanie , Fatouraei Maryam , Haeusser Daniel P. , Margolin William , Fenn Samuel , Turner Robert D. , Foster Simon J. , Rosato Adriana E. 
Published: October 2016

ABSTRACT

Antimicrobial resistance is recognized as one of the principal threats to public health worldwide, yet the problem is increasing. Infections caused by methicillin-resistant
Staphylococcus aureus
(MRSA) strains are among the most difficult to treat in clinical settings due to the resistance of MRSA to nearly all available antibiotics. The cyclic anionic lipopeptide antibiotic daptomycin (DAP) is the clinical mainstay of anti-MRSA therapy. The decreased susceptibility to DAP (DAP resistance [DAP
r
]) reported in MRSA is frequently accompanied by a paradoxical decrease in β-lactam resistance, a process known as the “seesaw effect.” Despite the observed discordance in resistance phenotypes, the combination of DAP and β-lactams has been proven to be clinically effective for the prevention and treatment of infections due to DAP
r
MRSA strains. However, the mechanisms underlying the interactions between DAP and β-lactams are largely unknown. In the study described here, we studied the role of
mprF
with DAP-induced mutations in β-lactam sensitization and its involvement in the effective killing by the DAP-oxacillin (OXA) combination. DAP-OXA-mediated effects resulted in cell wall perturbations, including changes in peptidoglycan insertion, penicillin-binding protein 2 (PBP 2) delocalization, and reduced membrane amounts of PBP 2a, despite the increased transcription of
mecA
through
mec
regulatory elements. We have found that the VraSR sensor-regulator is a key component of DAP resistance, triggering mutated
mprF
-mediated cell membrane (CM) modifications that result in impairment of PrsA location and chaperone functions, both of which are essential for PBP 2a maturation, the key determinant of β-lactam resistance. These observations provide for the first time evidence that synergistic effects between DAP and β-lactams involve PrsA posttranscriptional regulation of CM-associated PBP 2a.
Active-Site Protonation States in an Acyl-Enzyme Intermediate of a Class A β-Lactamase with a Monobactam Substrate
Authors: Vandavasi Venu Gopal , Langan Patricia S. , Weiss Kevin L. , Parks Jerry M. , Cooper Jonathan B. , Ginell Stephan L. , Coates Leighton 
Published: October 2016

ABSTRACT

The monobactam antibiotic aztreonam is used to treat cystic fibrosis patients with chronic pulmonary infections colonized by
Pseudomonas aeruginosa
strains expressing CTX-M extended-spectrum β-lactamases. The protonation states of active-site residues that are responsible for hydrolysis have been determined previously for the apo form of a CTX-M β-lactamase but not for a monobactam acyl-enzyme intermediate. Here we used neutron and high-resolution X-ray crystallography to probe the mechanism by which CTX-M extended-spectrum β-lactamases hydrolyze monobactam antibiotics. In these first reported structures of a class A β-lactamase in an acyl-enzyme complex with aztreonam, we directly observed most of the hydrogen atoms (as deuterium) within the active site. Although Lys 234 is fully protonated in the acyl intermediate, we found that Lys 73 is neutral. These findings are consistent with Lys 73 being able to serve as a general base during the acylation part of the catalytic mechanism, as previously proposed.
Congenital Cytomegalovirus: a “Now” Problem—No Really, Now
Authors: Bernstein David I. 
Published: October 2016

ABSTRACT

Despite the clear need, progress toward a vaccine for congenital cytomegalovirus (CMV) has been slow. However, recent events have provided new interest, and several vaccine candidates are either in clinical trials or the trials are close to starting. In this issue of
Clinical and Vaccine Immunology
, Schleiss and colleagues show that a nonreplicating lymphocytic choriomeningitis virus (rLCMV)-vectored vaccine expressing CMV glycoprotein B (gB) and/or pp65 induces B and T cells and improves pup survival in a guinea pig model of congenital CMV infection (Clin Vaccine Immunol 24:e00300-16, 2017,
https://doi.org/10.1128/CVI.00300-16
). The combination vaccine appeared to be the most effective.
SNAP23-Dependent Surface Translocation of Leukotriene B
4
(LTB
4
) Receptor 1 Is Essential for NOX2-Mediated Exocytotic Degranulation in Human Mast Cells Induced by Trichomonas vaginalis-Secreted LTB
4
Authors: Min Arim , Lee Young Ah , Kim Kyeong Ah , El-Benna Jamel , Shin Myeong Heon 
Published: October 2016

ABSTRACT

Trichomonas vaginalis
is a sexually transmitted parasite that causes vaginitis in women and itself secretes lipid mediator leukotriene B
4
(LTB
4
). Mast cells are important effector cells of tissue inflammation during infection with parasites. Membrane-bridging SNARE (soluble
N
-ethylmaleimide-sensitive factor attachment protein receptor) complexes are critical for fusion during exocytosis. Although
T. vaginalis
-derived secretory products (TvSP) have been shown to induce exocytosis in mast cells, information regarding the signaling mechanisms between mast cell activation and TvSP is limited. In this study, we found that SNAP23-dependent surface trafficking of LTB
4
receptor 1 (BLT1) is required for nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2)-mediated exocytotic degranulation of mast cells induced by TvSP. First, stimulation with TvSP induced exocytotic degranulation and reactive oxygen species (ROS) generation in HMC-1 cells. Next, TvSP-induced ROS generation and exocytosis were strongly inhibited by transfection of BLT1 small interfering RNA (siRNA). TvSP induced trafficking of BLT1 from the cytosol to the plasma membrane. We also found that knockdown of SNAP23 abrogated TvSP-induced ROS generation, exocytosis, and surface trafficking of BLT1 in HMC-1 cells. By coimmunoprecipitation, there was a physical interaction between BLT1 and SNAP23 in TvSP-stimulated HMC-1 cells. Taken together, our results suggest that SNAP23-dependent surface trafficking of BLT1 is essential for exocytosis in human mast cells induced by
T. vaginalis
-secreted LTB
4
. Our data collectively demonstrate a novel regulatory mechanism for SNAP23-dependent mast cell activation of
T. vaginalis
-secreted LTB
4
involving surface trafficking of BLT1. These results can help to explain how the cross talk mechanism between parasite and host can govern deliberately tissue inflammatory responses.
Immunity Provided by an Outer Membrane Vesicle Cholera Vaccine Is Due to O-Antigen-Specific Antibodies Inhibiting Bacterial Motility
Authors: Wang Zhu , Lazinski David W. , Camilli Andrew 
Published: October 2016

ABSTRACTAn outer membrane vesicle (OMV)-based cholera vaccine is highly efficacious in preventing intestinal colonization in the suckling mouse model. Immunity from OMVs comes from immunoglobulin (Ig), particularly IgG, in the milk of mucosally immunized dams. Anti-OMV IgG rendersVibrio choleraeorganisms immotile, thus they pass through the small intestine without colonizing. However, the importance of motility inhibition for protection and the mechanism by which motility is inhibited remain unclear. By using bothin vitroandin vivoexperiments, we found that IgG inhibits motility by specifically binding to the O-antigen ofV. cholerae. We demonstrate that the bivalent structure of IgG, although not required for binding to the O-antigen, is required for motility inhibition. Finally, we show using competition assays in suckling mice that inhibition of motility appears to be responsible for most, if not all, of the protection engendered by OMV vaccination, thus providing insight into the mechanism of immune protection.
A Pyrosequencing-Based Approach to High-Throughput Identification of Influenza A(H3N2) Virus Clades Harboring Antigenic Drift Variants
Authors: Mishin Vasiliy P. , Baranovich Tatiana , Garten Rebecca , Chesnokov Anton , Abd Elal Anwar I. , Adamczyk Michelle , LaPlante Jennifer , St. George Kirsten , Fry Alicia M. , Barnes John , Chester Stephanie C. , Xu Xiyan , Katz Jacqueline M. , Wentworth David E. , Gubareva Larisa V. 
Published: October 2016

ABSTRACT

The rapid evolution of influenza A(H3N2) viruses necessitates close monitoring of their antigenic properties so the emergence and spread of antigenic drift variants can be rapidly identified. Changes in hemagglutinin (HA) acquired by contemporary A(H3N2) viruses hinder antigenic characterization by traditional methods, thus complicating vaccine strain selection. Sequence-based approaches have been used to infer virus antigenicity; however, they are time consuming and mid-throughput. To facilitate virological surveillance and epidemiological studies, we developed and validated a pyrosequencing approach that enables identification of six HA clades of contemporary A(H3N2) viruses. The identification scheme of viruses of the H3 clades 3C.2, 3C.2a, 3C.2b, 3C.3, 3C.3a, and 3C.3b is based on the interrogation of five single nucleotide polymorphisms (SNPs) within three neighboring HA regions, namely 412 to 431, 465 to 481, and 559 to 571. Two bioinformatics tools, IdentiFire (Qiagen) and FireComb (developed in-house), were utilized to expedite pyrosequencing data analysis. The assay's analytical sensitivity was 10 focus forming units, and respiratory specimens with threshold cycle (

C
T

) values of <34 typically produced good quality pyrograms. When applied to 120 A(H3N2) virus isolates and 27 respiratory specimens, the assay displayed 100% agreement with clades determined by HA sequencing coupled with phylogenetics. The multi-SNP analysis described here was readily adopted by another laboratory with pyrosequencing capabilities. The implementation of this approach enhanced the findings from virological surveillance and epidemiological studies between 2013 and 2016, which examined more than 3,000 A(H3N2) viruses.
Ankyrin Repeat Proteins of Orf Virus Influence the Cellular Hypoxia Response Pathway
Authors: Chen Da-Yuan , Fabrizio Jacqueline-Alba , Wilkins Sarah E. , Dave Keyur A. , Gorman Jeffrey J. , Gleadle Jonathan M. , Fleming Stephen B. , Peet Daniel J. , Mercer Andrew A. 
Published: October 2016

ABSTRACT

Hypoxia-inducible factor (HIF) is a transcriptional activator with a central role in regulating cellular responses to hypoxia. It is also emerging as a major target for viral manipulation of the cellular environment. Under normoxic conditions, HIF is tightly suppressed by the activity of oxygen-dependent prolyl and asparaginyl hydroxylases. The asparaginyl hydroxylase active against HIF, factor inhibiting HIF (FIH), has also been shown to hydroxylate some ankyrin repeat (ANK) proteins. Using bioinformatic analysis, we identified the five ANK proteins of the parapoxvirus orf virus (ORFV) as potential substrates of FIH. Consistent with this prediction, coimmunoprecipitation of FIH was detected with each of the ORFV ANK proteins, and for one representative ORFV ANK protein, the interaction was shown to be dependent on the ANK domain. Immunofluorescence studies revealed colocalization of FIH and the viral ANK proteins. In addition, mass spectrometry confirmed that three of the five ORFV ANK proteins are efficiently hydroxylated by FIH
in vitro
. While FIH levels were unaffected by ORFV infection, transient expression of each of the ORFV ANK proteins resulted in derepression of HIF-1α activity in reporter gene assays. Furthermore, ORFV-infected cells showed upregulated HIF target gene expression. Our data suggest that sequestration of FIH by ORFV ANK proteins leads to derepression of HIF activity. These findings reveal a previously unknown mechanism of viral activation of HIF that may extend to other members of the poxvirus family.

IMPORTANCE
The protein-protein binding motif formed from multiple repeats of the ankyrin motif is common among chordopoxviruses. However, information on the roles of these poxviral ankyrin repeat (ANK) proteins remains limited. Our data indicate that the parapoxvirus orf virus (ORFV) is able to upregulate hypoxia-inducible factor (HIF) target gene expression. This response is mediated by the viral ANK proteins, which sequester the HIF regulator FIH (factor inhibiting HIF). This is the first demonstration of any viral protein interacting directly with FIH. Our data reveal a new mechanism by which viruses reprogram HIF, a master regulator of cellular metabolism, and also show a new role for the ANK family of poxvirus proteins.