bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD Analysis of Subcooled Wall Boiling at Shell Side of Steam Generator With TSP
Authors: Wang Chenglong , Zhang Dalin , Qiu Suizheng , Tian Wenxi , Su Guanghui
Published: November 2014

This paper addresses the numerical simulation of two-phase flow heat transfer among the tube bundles with tube support plate (TSP) of an integral type pressurized water reactor steam generator using RPI wall boiling model. The subcooled nucleate boiling phenomenon and the coupled heat transfer between the SG primary side and secondary side were obtained. Also, the effects of tube support plate (TSP) and the different inlet subcooling on the thermal-hydraulic characteristics of SG were studied. From the results of the present numerical simulation, it reasonably revealed the subcooled flow boiling occurred in the SG secondary side and the distributions of key parameters around TSP, elucidating that this model can provide useful information to the design of the steam generator.
An Improved Model to Study the Density Wave Oscillation in Tubes by Using Frequency Domain Method
Authors: Zhang Yifan , Li Huixiong , Wang Tai , Zhang Weiqiang , Sheng Tianyou
Published: November 2014

Density Wave Oscillation (DWO) in tubes was usually studied by using the frequency domain method. However, in the conventional model, the heat storage of wall metal was usually neglected to simplify the complex solving process of transfer functions, which might cause unreasonable results when the tube wall had a thick wall or complex geometry structures. Hence, in the present paper, an improved mathematical model was proposed based on the frequency domain theory to theoretically study the DWO in tubes. The present model was an improvement of the conventional model. The most notable improvement in the present model was that the heat storage of the tube wall metal, the internal wall heat flux and the external wall heat flux were all considered as dynamic parameters. Based on the improvement, the prediction of the DWO in tubes by using the present model might be more accurate and reasonable than that by using the conventional model, and this was proved by the comparison of the results obtained with the two models to the experimental results gained from literature. In the present study, it was shown that both the present model and the conventional model could predict the DWO in tubes well when the tube wall was thin, and it was also found that the present model was more appropriate than the conventional model when the tube wall was thick. Both the thickness of the tube wall and the specific heat of tube wall metal play negative roles in the system stability.
Heat Removal Capability of Core-Catcher in Consideration of Transformation of Cooling Channel
Authors: Kurita Tomohisa , Komuro Mitsuo , Suzuki Ryo , Yamada Masato , Tahara Mika , Yanagisawa Hiromasa
Published: November 2014

It is necessary to stabilize high temperature molten core in a severe accident for long time without electrical power. The core-catcher is to be installed at the bottom of the lower drywell in order to settle the molten core flowing down from a reactor vessel.

Toshiba’s core-catcher system consists of a round basin made up of inclined cooling channels to get natural circulation of the flooding water. So it can cover all pedestal floor and can work in passive manner.

We have been confirming an applicability of the core-catcher to actual plants. We have conducted full scaled tests with a unique cooling channel which has inclined rectangular flow section and changing the section area along flow direction in several conditions to evaluate the influence of the parameters on the natural circulation and heat removal capability. The test results showed good heat removal performance with nucleate boiling.

However, we should consider a transformation of the cooling channel, for example, by the falling corium. So we calculate the assumed transformation of the cooling channel and conduct natural circulation tests with obstruction in the cooling channel. We confirm that natural circulation flow is stably continues and the cooling channel can remove prescribed heat, even if a flow area have got narrow locally.
Analysis of the Damage Domains of SBO Sequences With RCP Passive Thermal Shutdown
Authors: Queral C. , Mena-Rosell L. , Jimenez G. , Sánchez-Perea M. , Hortal J. , Gómez-Magán J.
Published: November 2014

The integrated Safety Assessment (ISA) methodology, developed by the Spanish Nuclear Safety Council (CSN), has been applied to a thermal-hydraulic analysis of PWR Station Blackout (SBO) sequences in the context of the IDPSA (Integrated Deterministic-Probabilistic Safety Assessment) network objectives. The ISA methodology allows obtaining the damage domain (the region of the uncertain parameters space where the damage limit is exceeded) for each sequence of interest as a function of the operator actuations times. Given a particular safety limit or damage limit, several data of every sequence are necessary in order to obtain the exceedance frequency of that limit. In this application these data are obtained from the results of the simulations performed with MAAP code transients inside each damage domain and the time-density probability distributions of the manual actions. Damage limits that have been taken into account within this analysis are: local cladding damage (PCT>1477 K); local fuel melting (T>2499 K); fuel relocation in lower plenum and vessel failure. Therefore, to every one of these damage variables corresponds a different damage domain. The operation of the new passive thermal shutdown seals developed by several companies since Fukushima accident is considered in the paper. The results show the capability and necessity of the ISA methodology, or similar, in order to obtain accurate results that take into account time uncertainties.
Comparison of CORA and MELCOR Core Degradation Simulation and MELCOR Oxidation Model
Authors: Wang Jun , Corradini Michael L. , Fu Wen , Haskin Troy , Tian Wenxi , Zhang Yapei , Su Guanghui , Qiu Suizheng
Published: November 2014

MELCOR is widely used and sufficiently trusted for severe accident analysis. However, the occurrence of Fukushima has increased the focus on severe accident codes and their use. A MELCOR core degradation calculation was conducted at the University of Wisconsin – Madison. The calculation results were checked by comparing with a past CORA experiment. MELCOR calculation results included the flow rate of argon and steam, the generation rate of hydrogen. Through this work, the performance of MELCOR COR package was reviewed in detail. This paper compares the hydrogen generation rates predicted by MELCOR to the CORA test data. While agreement is reasonable it could be improved. Additionally, the MELCOR zirconium oxidation model was analyzed.
Assessment Study of RELAP5/SCDAP Capability to Reproduce Liquid Metal Fluid Thermal Hydraulic Behaviour
Authors: Fiori F. , Zhou Zhiwei
Published: November 2014

The paper presents the assessment of RELAP5/SCDAP code capabilities to simulate the thermal-hydraulic behavior of liquid metal coolants. The preliminary part of the study dealt with a bibliographic review of the heat transfer correlations available for liquid metals, in particular for lead-bismuth eutectic. The most appropriate correlation, according to the thermal-hydraulic condition of the Chinese ADS design has been implemented and tested in the code. The experiment facilities used for the assessment study are the South Korean HELIOS facility, the KYLIN-II facility and the TALL facility. The first one is a T-H loop which is down scaled by a factor of 5000 of the reference PEACER-300 concept reactor, and has been recently used for an international benchmark organized by the OECD/NEA. As the first phase of the benchmark is concluded, the data is available in the open literature. The second facility is constructed and operated in the Institute of Nuclear Safety Energy of the Chinese Academy of Science in Hefei (CAS). The third facility has been constructed and operated at KTH Royal Institute of Technology of Stockholm. The full height facility was designed and operated to investigate the heat transfer performance of different heat exchangers and the thermal-hydraulic characteristics of natural and forced circulation flow under steady and transient conditions. A consistent and systematic approach for the nodalization development and assessment procedures that respond to the IAEA guidelines is discussed and thoroughly applied. The present paper discusses the results of the assessment study of the RELAP5/SCDAP capability when working with liquid metal fluid. The procedures and the database developed constitute the base in our institute for further study in case more experimental data will be available.
Japanese Codes and Standards for Dual Purpose Metal Casks for Spent Nuclear Fuel
Authors: Saegusa Toshiari , Hirose Makoto , Irie Norikazu , Shimizu Masashi
Published: November 2014

The first Japanese spent fuel interim storage facility away from a reactor site is about to be commissioned in Mutsu City, Aomori Prefecture. In designing, licensing and construction of the Dual Purpose Casks (DPCs, for transport and storage) for this facility, codes and standards established by the Atomic Energy Society of Japan (AESJ) and by the Japan Society of Mechanical Engineers (JSME) have been applied.

The AESJ established the first standard for DPCs as “Standard for Safety Design and Inspection of Metal Casks for Spent Fuel Interim Storage Facilities” in 2002 (later revised in 2010). The standard provides the design requirements to maintain the basic safety functions of DPCs, namely containment, heat removal, shielding, criticality prevention and the structural integrity of the cask itself and of the spent fuel cladding during transport and storage. Inspection methods and criteria to ensure maintenance of the basic safety functions and structural integrity over every stage of operations involving DPCs including pre-shipment after storage are prescribed as well. The structural integrity criteria for major DPC components refer to the rules provided by the JSME.

JSME completed the structural design and construction code (the Code) for DPCs as “Rules on Transport/Storage Packagings for Spent Nuclear Fuel” in 2001 (later revised in 2007). Currently, the scope of the rules cover the Containment Vessel, Basket, Trunnions and Intermediate Shell as major components of DPCs. Rules for these components are based on those for components of nuclear power plants (NPP) with similar safety functions, but special considerations based on their shapes, loading types and required functions are added.

The Code has differences from that for NPP components with considerations to DPC characteristics;

- The primary stress and the secondary stress generated in Containment Vessels shall be evaluated under Service Conditions A to D (from ASME Sec III, Div.1).

- Stress generated in the seal region lid bolts of Containment Vessels shall not exceed yield strength under Service Conditions A to D in order to maintain the containment function.

- Fatigue analysis on Baskets is not required, and Trunnions can be designed only for Service Conditions A and B with special stress limits consistent with conventional assessment methods for transport packages.

- Stress limits for earthquakes during storage are specified.

- Ductile cast iron with special fracture toughness requirements can be used as a material for Containment Vessels.

DPC specific considerations in standards and rules will be focused on in this paper. Additionally, comparison with the ASME Code will be discussed.
Development of Steam Generator Model Using RELAP5 to Simulate Two-Phase Natural Circulation for Pressurized Water Reactor
Authors: Miyata Shinya , Kamohara Satoru , Sakuma Wataru , Nishi Hiroaki
Published: November 2014

In typical pressurized water reactor (PWR), to cope with beyond design basis events such as station black out (SBO) or small break loss of coolant accident with safety injection system failure, injection from accumulator sustains core cooling by compensating for loss of coolant. Core cooling is sustained by single- or two-phase natural circulation or reflux condensation depending on primary coolant mass inventory. Behavior of the natural circulation in PWR has been investigated in the facilities such as Large Scale Test Facility (LSTF) which is a full-height and full-pressure and thermal-hydraulic simulator of typical four-loop PWR. Two steady-state natural circulation tests were conducted in LSTF at both high and low pressure. These two tests were conducted changing the primary mass inventory as a test parameter, while keeping the other parameters such as core power, steam generator (SG) pressure, and steam generator water level as they are.

Mitsubishi Heavy Industries (MHI) plans new natural circulation tests to cover wider range of core power and pressure as test-matrix (including the previous LSTF tests) to validate applicability of the model in wider range of core power and pressure conditions including the SBO conditions. In this paper, the previous LSTF natural circulation tests are reviewed and the new test plan will be described. Additionally, MHI also started a feasibility study to improve the steam generator tube and inlet/outlet plenum model using the M-RELAP5 code [4]. Newly developed model gives reasonable agreement with the previous LSTF tests and applies to the new test conditions. The feasibility findings will also be described in this paper.
HTR-PM Simulation Analysis of Accident Conditions Based on vPower Platform
Authors: Yang Tang , Zhou Yangping , Zhou Zhiwei , Dabin Zhang
Published: November 2014

HTR engineering simulator can be achieved by embedding THERMIX code into the vPower simulation environment. The engineering simulator consists of double-module reactors, two steam generators and entire secondary loop system for power generation with a water-steam Rankin cycle. The engineering simulator can be applied to simulate the steady-state operation, but also transient and accident state of HTR-PM. This paper analyzes the trends of reactor power, helium flow, steam generator inlet parameters, turbine inlet parameters and other key parameters under accident conditions, as well as the mutual influence between the two module reactors during accident process. Current simulation results are in good agreement with the design values and safety analysis results of HTR-PM.
Modeling of Cladding Thermal Evolution Along Cask Storage
Authors: Penalva Jaime E. , Feria Francisco , Herranz Luis E.
Published: November 2014

One of the safety requirements in dry storage of spent fuel is to ensure the cladding integrity. In this regard, the understanding of the cladding mechanical performance along the storage period is indispensable, both to analyse the failure probability and to characterize the state of the cladding so that fuel management is conducted with accurate knowledge of the material conditions. The main interest is focused on cladding degrading mechanisms as creep and hydrogen related (e.g. hydrides embrittlement), which are strongly influenced by temperature. Therefore, cladding thermal characterization along dry storage is an important element to predict fuel rod mechanical performance.

Cladding temperature decay models found in the literature are fuel burnup independent and they cannot be applied to storage periods longer than some decades. The goal of this work is to develop a simplified model of cladding temperature as a function of burnup that spans up to 300 years of cask storage. To do so, a methodology is established based on FLUENT steady state calculations fed by heat decay data found in the literature for different burnups (33–63 MWd/kgU). From the results, a temperature correlation as a function of burnup and out-of-reactor time has been derived. It shows an average relative error less than 2% with respect FLUENT calculations.

Finally, significance of having an accurate thermal characterization of the fuel rod has been highlighted by comparing fuel rod thermo-mechanics based on the derived correlation and the one resulting from using a correlation developed by EPRI.
Implications of Applying Semi-Scale Pump Test Data to Two-Phase RCP Performance Modeling for PWR LOCA Analyses
Authors: Jacob Mathew C. , Coon Michael T. , Blaisdell John A. , Espinosa Ruben J.
Published: November 2014

Emergency Core Cooling System (ECCS) analyses using Loss of Coolant Accident (LOCA) codes utilize two-phase Reactor Coolant Pump (RCP) performance models formulated on the basis of data from tests conducted on the Semi-scale pump (Reference 1) operating at 60 Hz frequency. In some PWRs, the RCPs operate at a frequency of 50 Hz. This paper presents the results of an evaluation performed to determine the applicability of RCP two-phase performance models developed on the basis of data from the Semi-scale tests for analyzing ECCS performance of new generation PWRs. The evaluation addressed two major issues: (1) the applicability of the two-phase RCP performance model developed using the data from the Semi-scale pump tests (Reference 1) for full scale Pressurized Water Reactor (PWR) LOCA simulations, and (2) the relevance of the two-phase RCP performance model developed on the basis of test data for the Semi-scale pumps running at 60 Hz frequency to PWR RCPs running at 50 Hz frequency with higher specific speeds.

Reviews of pump performance test data available in the open literature identified two-phase performance data appropriate for use in substantiating the validity of current PWR pump performance models. These data supported the conclusion that the two-phase head performance degradation for the Semi-scale Mod-1 pump is conservative compared to the two-phase pump performance data generated from testing of pumps representative of full scale PWR RCPs. A review of ECCS analyses results available in the literature determined that the use of the current RCP two-phase performance model (developed using the Semi-scale Mod-1 pump test data) for a typical PWR plant resulted in about a 100 °F increase in the Peak Clad Temperature (PCT) for a Large Break LOCA (LBLOCA) in comparison to the PCTs calculated using the two-phase pump performance model developed on the basis of test data for pumps representative of full scale PWR RCPs.

It was determined from the current study that the frequency (50 Hz vs. 60 Hz) of the electrical power that drives the pump motor is not of much consequence for two-phase RCP performance modeling, since (1) the RCP performance model is characterized via normalized pump performance parameters, and (2) for the LBLOCA analysis of interest, the RCPs are assumed to lose power at the start of the event.
Modelling of Water Ingress in to Vacuum Vessel
Authors: Kaliatka Tadas , Ušpuras Eugenijus , Kaliatka Algirdas
Published: November 2014

An event of water coolant ingress into vacuum vessel is one of the most important events leading to severe consequences in nuclear fusion reactors. The ingress of coolant to the vacuum vessel could appear due to coolant pipe rupture of in-vessel components. Vacuum vessel could not withstand the high pressure inside. Pressure increase in vacuum vessel is due to water evaporation because of pressure difference and water contact with high temperature plasma facing components. If pressure in vacuum vessel is too high — safety valve opens and the steam containing activated dust will be transferred form the vacuum vessel to the environment. Therefore, it is important to understand the thermo hydraulic processes in vacuum vessel during the ingress of coolant event (ICE).

There are few experimental investigations performed, modeling of ICE. In this article ingress of coolant event in vacuum vessel was modeled using RELAP5 code. RELAP5 is a “best estimate” system code suitable for the thermo-hydraulic analysis of all transients and postulated accidents in nuclear fission, light water reactor systems, including both large and small-break loss-of-coolant accidents as well as the full range of operational transients. The use of RELAP5 code for the accident analysis in nuclear fusion reactors allows to perform integral analysis of thermal-hydraulic processes in the cooling system and vacuum vessel. The comparisons of calculation results and experimental data showed that with some limitations the RELAP5 program could be used for the analysis of the thermal hydraulic processes in the vacuum vessel during ICE.
Computational Simulation of Turbulent Natural Convection in a Volumetrically Heated Hemispherical Cavity
Authors: Vieira Camila Braga , Ničeno Bojan , Su Jian
Published: November 2014

This work presents an analysis of the turbulent natural convection in a volumetrically hemisphere cavity, representing a lower plenum of a Light Water Reactor (LWR) vessel. Considering isothermal top and bottom walls at temperature of 298.5 K and a fluid with Prandtl number (Pr) equal to 8.52, the experiment performed by Asfia et al. [1] was reproduced, so that their experimental data could be used for the validation of the numerical data provided by the present work. Ranging the internal Rayleigh numbers (Rai) from 108 to 3.03 × 1013, numerical simulations were performed using the open-source Computational Fluid Dynamics (CFD) code OpenFOAM (Open Field Operation and Manipulation), making use of the “code-friendly” modification of the turbulence model V2-f, a Reynolds Averaged Navier-Stokes (RANS) based equation model. The calculation of the turbulent heat fluxes was done by the Simple Gradient Diffusion Hypothesis (SGDH), which proved to be adequate for the case considered. Bearing in mind the complexity of the phenomena inside a molten core after a severe accident in a nuclear power plant, some assumptions were done such as the fluid was considered Newtonian, with no-phase change and homogeneous. Numerical correlations of Nusselt number (Nu¯) over the bottom and top walls as function of the Rai were obtained and a good agreement with the experimental data provided by Asfia et al. [1] was reached for the local heat transfer with respect to the angle for the cooled top wall.
Shipment of Spent Nuclear Fuel From the Czech Republic for Reprocessing
Authors: Podlaha Josef
Published: November 2014

After more than 50 years of operation of the research reactor operated by ÚJV Řež, a. s. (ÚJV) or the Research Centre Řež, as the case may be, a large amount of spent nuclear fuel (SNF) of Russian origin has accumulated.

In 2005, ÚJV joined the Russian Research Reactor Fuel Return (RRRFR) program under the US-Russian Global Threat Reduction Initiative (GTRI) and started the process of SNF shipment from the LVR-15 research reactor back to the Russian Federation (RF) using the ŠKODA VPVR/M transport packaging system (TPS). Two SNF shipments from ÚJV were carried out in 2007 and 2013. After the shipments were completed, only low-enriched nuclear fuel with a maximum enrichment below 20% of 235U remained on the territory of the Czech Republic.

ÚJV also participates in shipments of SNF from other countries. The services of ÚJV comprise mainly ŠKODA VPVR/M TPS leasing, technical oversight and expertise during cask handling, SNF loading and cask closing and sealing. Up to now, ÚJV has participated in thirteen shipments of SNF from eight countries; one shipment is currently being prepared.

High-level radioactive waste (HLW) will be generated from SNF reprocessing. The vitrified HLW will be returned to the Czech Republic as stated in the Russian-Czech Intergovernmental Agreement on Co-operation in Nuclear Energy. The return of the waste represents very complex and complicated work, technically, legally and contractually.
Development of Inherently Safe Technologies for Large Scale BWRs: (5) Operation Support System for Plant Accidents
Authors: Kanada Masaki , Kamoshida Ryota , Ishii Yoshihiko , Ishikawa Tadaaki , Arita Setsuo , Katono Kenichi
Published: November 2014

When accident events are caused by a large-scale natural disaster, conditions beyond those at the plant site may affect the accident. As well, quick diagnosis and recognition of damaged equipment are necessary. We have been developing inherently safe technologies for boiling water reactor (BWR) plants in response to these. An operation support system for plant accident events is one of these technologies. Our operation support system identifies accident events and predicts the progression of plant behavior.

The system consists of three main functions: sensor integrity diagnosis, accident event identification, and plant simulation functions.

The sensor integrity diagnosis function diagnoses whether sensor signals have maintained their integrity by correlating redundant sensors with the plant design information.

The accident event identification function extracts a few of candidate accident events using alarm and normal sensor signals received by the sensor integrity diagnosis function. The scale and position of the accident event are determined by comparing plant simulation results with normal sensor signals.

The plant simulation function uses a detailed three-dimensional model of the nuclear reactor and plant. This simulation can predict future plant behavior on the basis of identified accident events.

This proposed operation support system provides available results of accident event identification and plant condition prediction to plant operators. This system will reduce the occurrence of false identifications of accident events and human errors of operators.
Testing of Purification and Purity Control System High Temperature Helium Loop
Authors: Berka Jan , Dámer Jozef
Published: November 2014

Helium purification system as a part of the HTHL and helium purification methods for future HTR or GFR reactors was tested in the series of experiments. The experiments were aimed (among others) to operation of CuO unit, which is part of the helium purification system. This unit is used for converting some minor impurities in helium coolant (namely H2 and CO) to compounds, which can be easily removed on molecular sieve adsorbents (H2O, CO2).

The CuO oxidation capabilities were tested at several temperatures (100, 150, 200 and 250°C) for helium containing different impurities. Final oxidation products were removed by molecular sieves after stabilization of gas composition inside the HTHL. The CuO oxidizer bed showed good performance in H2 and CO oxidation. The overall oxidation efficiency is highly dependable on CuO bed temperature.
Fault Insertion Testing of FPGA-Based NPP I&C Systems: SIL Certification Issues
Authors: Kharchenko Vyacheslav , Odarushchenko Oleg , Sklyar Vladimir , Ivasyuk Alexandr
Published: November 2014

Features of verification FPGA-based safety critical I&C systems (FBIC) using of fault-insertion technique (FIT) are analyzed. The FIT is applied in process of certification to meet requirements of IEC 61508 according with safety integrity level (SIL). Specific aspects of FBIC SIL-certification are described. Concept of FIT-ability, theoretical issues and optimal FIT procedure taking into account different points and means of fault insertion are offered. The developed technique and tool to verify FPGA-based platform RadICS using FIT procedure during SIL-certification are described.
Learning Through Delivery, Westinghouse AP1000® Plant Licensing
Authors: Gorgemans Julie , Corletti Michael M. , DeLong Richard A. , Schulz Terry L.
Published: November 2014

The AP1000® plant is an 1100-MWe pressurized water reactor (PWR) with passive safety features and extensive plant simplifications that enhance construction, operation, maintenance, safety, and costs.

Four AP1000 units are currently under construction on coastal sites of Sanmen and Haiyang, China. Additionally, the United States (US) Nuclear Regulatory Commission (NRC) issued combined licenses (COLs) to allow Southern Nuclear Operating Company (SNC) & South Carolina Electric & Gas Company (SCE&G) to construct and operate AP1000 plants at the existing Vogtle & VC Summer sites in Georgia and South Carolina, respectively. Although construction at both US sites is underway, the first four China AP1000 plants will become operational ahead of the U.S. Domestic AP1000 plants. Westinghouse is also actively engaged in deploying the AP1000 plant design in other regions throughout the world such as Europe. For example, the AP1000 plant design was evaluated by the UK Office for Nuclear Regulation as part of the UK Generic Design Assessment and received a statement of interim Design Acceptance in late 2011.

This paper reviews the past and on-going AP1000 plant licensing activities and discusses how the significant lessons learned gathered through the AP1000 plant worldwide deployment increase licensing certainty for any new AP1000 project.
Complete Genome Sequence of vB_EcoM_112, a T-Even-Type Bacteriophage Specific for Escherichia coli O157:H7
Authors: Coffey Brid , Ross R. Paul , O'Flynn Gary , O'sullivan Orla , Casey Aidan , Callanan Michael , Coffey Aidan , McAuliffe Olivia
Published: November 2014

Bacteriophage vB_EcoM_112 (formerly e11/2) is an
Escherichia coli
phage with specificity for the O157:H7 serotype. The vB_EcoM_112 genome sequence shares high degrees of similarity with the phage T4 genome sequence.
Draft Genome Sequences of Marine Flavobacterium
Nonlabens
Strains NR17, NR24, NR27, NR32, NR33, and Ara13
Authors: Nakanishi Masato , Meirelles Pedro , Suzuki Ryohei , Takatani Naoki , Mino Sayaka , Suda Wataru , Oshima Kenshiro , Hattori Masahira , Ohkuma Moriya , Hosokawa Masashi , Miyashita Kazuo , Thompson Fabiano L. , Niwa Ako , Sawabe Toko , Sawabe Tomoo
Published: November 2014

Here, we present the draft genome sequences of six carotenoid producers affiliated with
Nonlabens
spp. isolated from marine environments in both the northern and southern parts of Japan. The genomic information will help to elucidate the function and evolution of carotenoid synthetic gene clusters not only in the genus
Nonlabens
but also in the family
Flavobacteriaceae
.
Doubly connected domination in the join and Cartesian product of some graphs
Authors: Arriola Benjier H. , Canoy Sergio R.
Published: November 2014

Let G be a simple connected graph. A connected dominating set S ⊂ V(G) is called a doubly connected dominating set of G if the subgraph 〈V(G)\S〉 induced by V(G)\S is connected. We show that given any three positive integers a, b, and c with 4 ≤ a ≤ b ≤ c, where b ≤ 2a, there exists a connected graph G such that a = γr(G), b = γtr(G), and c = γcc(G), where γr, γtr, and γcc are, respectively, the restrained domination, total restrained domination, and doubly connected domination parameters. Also, we characterize the doubly connected dominating sets in the join of any graphs and Cartesian product of some graphs. The corresponding doubly connected domination numbers of these graphs are also determined.
On some groups with only two types of subgroups
Authors: Kurdachenko L. A. , Subbotin I. Ya. , Velichko T. I.
Published: November 2014

In this paper, we study the groups whose subgroups are either almost normal or contranormal. The main theorem of the paper describes locally soluble groups with this property. We also provide a description of locally soluble group, whose subgroups are almost normal or abnormal.
Automatic quantitative analysis of t-tubule organization in cardiac myocytes using ImageJ
Authors: Pasqualin Côme , Gannier François , Malécot Claire O. , Bredeloux Pierre , Maupoil Véronique
Published: November 2014

The transverse tubule system in mammalian striated muscle is highly organized and contributes to optimal and homogeneous contraction. Diverse pathologies such as heart failure and atrial fibrillation include disorganization of t-tubules and contractile dysfunction. Few tools are available for the quantification of the organization of the t-tubule system. We developed a plugin for the ImageJ/Fiji image analysis platform developed by the National Institutes of Health. This plugin (TTorg) analyzes raw confocal microscopy images. Analysis options include the whole image, specific regions of the image (cropping), and z-axis analysis of the same image. Batch analysis of a series of images with identical criteria is also one of the options. There is no need to either reorientate any specimen to the horizontal or to do a thresholding of the image to perform analysis. TTorg includes a synthetic “myocyte-like” image generator to test the plugin's efficiency in the user's own experimental conditions. This plugin was validated on synthetic images for different simulated cell characteristics and acquisition parameters. TTorg was able to detect significant differences between the organization of the t-tubule systems in experimental data of mouse ventricular myocytes isolated from wild-type and dystrophin-deficient mice. TTorg is freely distributed, and its source code is available. It provides a reliable, easy-to-use, automatic, and unbiased measurement of t-tubule organization in a wide variety of experimental conditions.
Identification and characterization of the minimal 5′-regulatory region of the human riboflavin transporter-3 (SLC52A3) in intestinal epithelial cells
Authors: Ghosal Abhisek , Sabui Subrata , Said Hamid M.
Published: November 2014

The human riboflavin (RF) transporter-3 (product of the SLC52A3 gene) plays an important role in intestinal RF absorption. Our aims in this study were to identify the minimal 5′-regulatory region of the SLC52A3 gene and the regulatory element(s) involved in its activity in intestinal epithelial cells, as well as to confirm promoter activity and establish physiological relevance in vivo in transgenic mice. With the use of transiently transfected human intestinal epithelial HuTu 80 cells and 5′-deletion analysis, the minimal SLC52A3 promoter was found to be encoded between −199 and +8 bp (using the start of the transcription start site as position 1). Although several putative cis-regulatory elements were predicted in this region, only the stimulating protein-1 (Sp1) binding site (at position −74/−71 bp) was found to play a role in promoter activity, as indicated by mutational analysis. Binding of Sp1 to the minimal SLC52A3 promoter was demonstrated by means of EMSA and supershift assays and by chromatin immunoprecipitation analysis. Studies with Drosophila SL2 cells (which lack Sp activity) confirmed the importance of Sp1 in driving the activity of the SLC52A3 minimal promoter; they further showed that Sp3 can also do the activation. Finally, with the use of luciferase gene fusions, the activity of the cloned SLC52A3 promoter was confirmed in vivo in transgenic mice. These studies report, for the first time, on the identification and characterization of the SLC52A3 promoter and also demonstrate the importance of Sp1 in regulating its activity in intestinal epithelial cells.
Cellular inhibitor of apoptosis protein 2 controls human colonic epithelial restitution, migration, and Rac1 activation
Authors: Seidelin Jakob Benedict , Larsen Sylvester , Linnemann Dorte , Vainer Ben , Coskun Mehmet , Troelsen Jesper Thorvald , Nielsen Ole Haagen
Published: November 2014

Identification of pathways involved in wound healing is important for understanding the pathogenesis of various intestinal diseases. Cellular inhibitor of apoptosis protein 2 (cIAP2) regulates proliferation and migration in nonepithelial cells and is expressed in human colonocytes. The aim of the study was to investigate the role of cIAP2 for wound healing in the normal human colon. Wound tissue was generated by taking rectosigmoidal biopsies across an experimental ulcer in healthy subjects after 5, 24, and 48 h. In experimental ulcers, the expression of cIAP2 in regenerating intestinal epithelial cells (IECs) was increased at the wound edge after 24 h ( P < 0.05), returned to normal after reepithelialization, and correlated with the inflammatory reaction in the experimental wounds ( P < 0.001). cIAP2 was induced in vitro in regenerating Caco2 IECs after wound infliction ( P < 0.01). Knockdown of cIAP2 caused a substantial impairment of the IEC regeneration through inhibition of migration ( P < 0.005). cIAP2 overexpression lead to formation of migrating IECs and upregulation of expression of RhoA and Rac1 as well as GTP-activation of Rac1. Transforming growth factor-β1 enhanced the expression of cIAP2 but was not upregulated in wounds in vivo and in vitro. NF-κB and MAPK pathways did not affect cIAP2 expression. cIAP2 is in conclusion a regulator of human intestinal wound healing through enhanced migration along with activation of Rac1, and the findings suggest that cIAP2 could be a future therapeutic target to improve intestinal wound healing.
Effects of cerebral ischemia on human neurovascular coupling, CO2 reactivity, and dynamic cerebral autoregulation
Authors: Salinet Angela S. M. , Robinson Thompson G. , Panerai Ronney B.
Published: November 2014

Cerebral blood flow (CBF) regulation can be impaired in acute ischemic stroke but the combined effects of dynamic cerebral autoregulation (CA), CO2 cerebrovascular reactivity (CVR), and neurovascular coupling (NVC), obtained from simultaneous measurements, have not been described. CBF velocity in the middle cerebral artery (MCA) (CBFv, transcranial Doppler), blood pressure (BP, Finometer), and end-tidal Pco2 (PetCO2, infrared capnography) were recorded during a 1-min passive movement of the arm in 27 healthy controls [mean age (SD) 61.4 (6.0) yr] and 27 acute stroke patients [age 63 (11.7) yr]. A multivariate autoregressive-moving average model was used to separate the contributions of BP, arterial Pco2 (PaCO2), and the neural activation to the CBFv responses. CBFv step responses for the BP, CO2, and stimulus inputs were also obtained. The contribution of the stimulus to the CBFv response was highly significant for the difference between the affected side [area under the curve (AUC) 104.5 (4.5)%] and controls [AUC 106.9 (4.3)%; P = 0.008]. CBFv step responses to CO2 [affected hemisphere 0.39 (0.7), unaffected 0.55 (0.8), controls 1.39 (0.9)%/mmHg; P = 0.01, affected vs. controls; P = 0.025, unaffected vs. controls] and motor stimulus inputs [affected hemisphere 0.20 (0.1), unaffected 0.22 (0.2), controls 0.37 (0.2) arbitrary units; P = 0.009, affected vs. controls; P = 0.02, unaffected vs. controls] were reduced in the stroke group compared with controls. The CBFv step responses to the BP input at baseline and during the paradigm were not different between groups ( P = 0.07), but PetCO2 was lower in the stroke group ( P < 0.05). These results provide new insights into the interaction of CA, CVR, and NVC in both health and disease states.
Sulforaphane alleviates muscular dystrophy inmdxmice by activation of Nrf2
Authors: Sun Chengcao , Yang Cuili , Xue Ruilin , Li Shujun , Zhang Ting , Pan Lei , Ma Xuejiao , Wang Liang , Li Dejia
Published: November 2014

Sulforaphane (SFN), one of the most important isothiocyanates in the human diet, is known to have chemo-preventive and antioxidant activities in different tissues via activation of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated induction of antioxidant/phase II enzymes, such as heme oxygenase-1 and NAD(P)H quinone oxidoreductase 1. However, its effects on muscular dystrophy remain unknown. This work was undertaken to evaluate the effects of SFN on Duchenne muscular dystrophy. Four-week-old mdx mice were treated with SFN by gavage (2 mg·kg body wt−1·day−1for 8 wk), and our results demonstrated that SFN treatment increased the expression and activity of muscle phase II enzymes NAD(P)H quinone oxidoreductase 1 and heme oxygenase-1 with a Nrf2-dependent manner. SFN significantly increased skeletal muscle mass, muscle force (∼30%), running distance (∼20%), and GSH-to-GSSG ratio (∼3.2-fold) of mdx mice and decreased the activities of plasma creatine phosphokinase (∼45%) and lactate dehydrogenase (∼40%), gastrocnemius hypertrophy (∼25%), myocardial hypertrophy (∼20%), and malondialdehyde levels (∼60%). Furthermore, SFN treatment also reduced the central nucleation (∼40%), fiber size variability, and inflammation and improved the sarcolemmal integrity of mdx mice. Collectively, these results show that SFN can improve muscle function and pathology and protect dystrophic muscle from oxidative damage in mdx mice associated with Nrf2 signaling pathway, which indicate Nrf2 may have clinical implications for the treatment of patients with muscular dystrophy.
Antiangiogenic Therapy for Glioblastoma: Current Status and Future Prospects
Authors: Batchelor Tracy T. , Reardon David A. , de Groot John F. , Wick Wolfgang , Weller Michael
Published: November 2014

Glioblastoma is characterized by high expression levels of proangiogenic cytokines and microvascular proliferation, highlighting the potential value of treatments targeting angiogenesis. Antiangiogenic treatment likely achieves a beneficial impact through multiple mechanisms of action. Ultimately, however, alternative proangiogenic signal transduction pathways are activated, leading to the development of resistance, even in tumors that initially respond. The identification of biomarkers or imaging parameters to predict response and to herald resistance is of high priority. Despite promising phase II clinical trial results and patient benefit in terms of clinical improvement and longer progression-free survival, an overall survival benefit has not been demonstrated in four randomized phase III trials of bevacizumab or cilengitide in newly diagnosed glioblastoma or cediranib or enzastaurin in recurrent glioblastoma. However, future studies are warranted. Predictive markers may allow appropriate patient enrichment, combination with chemotherapy may ultimately prove successful in improving overall survival, and novel agents targeting multiple proangiogenic pathways may prove effective.

See all articles in this CCR Focus section, “Discoveries, Challenges, and Progress in Primary Brain Tumors.”

Clin Cancer Res; 20(22); 5612–9. ©2014 AACR.
Facing the Future of Brain Tumor Clinical Research
Authors: Gilbert Mark R. , Armstrong Terri S. , Pope Whitney B. , van den Bent Martin J. , Wen Patrick Y.
Published: November 2014

This edition of CCR Focus provides critical reviews of several important areas in the field, including the application of findings from genomic investigations of brain tumors to improve diagnosis, clinical trial design, and ultimately optimizing individual patient treatment. Another article is a critical review provided by experts in the field that discusses the recent clinical trials using angiogenesis inhibitors, possible explanations for the results, and how to move forward. There is a concise discussion of the application of immunotherapy to brain tumors by key investigators in this field, reflecting the potential opportunities as well as the disease-specific challenges. Finally, leading pediatric brain tumor investigators provide an overview of the field and insights about the recent seminal discoveries in two pediatric brain tumors, supporting the paradigm that laboratory investigations lead to more precise diagnosis, prognosis, and ultimately better treatment. Herein, an overview of the recent advances and challenges in the area of clinical and translational brain tumor research is provided to set the stage for the contributions that follow.

See all articles in this CCR Focus section, “Discoveries, Challenges, and Progress in Primary Brain Tumors.”

Clin Cancer Res; 20(22); 5591–600. ©2014 AACR.
Visual Selective Attention Is Impaired in Children Prenatally Exposed to Opioid Agonist Medication
Authors: Konijnenberg Carolien , Melinder Annika
Published: November 2014

Aims: To examine whether prenatal exposure to opioid agonist medication is associated with visual selective attention and general attention problems in early childhood. Method: Twenty-two children (mean age = 52.17 months, SD = 1.81) prenatally exposed to methadone, 9 children (mean age = 52.41 months, SD = 1.42) prenatally exposed to buprenorphine and 25 nonexposed comparison children (mean age = 51.44 months, SD = 1.31) were tested. Visual selective attention was measured with a Tobii 1750 Eye Tracker using a spatial negative priming paradigm. Attention problems were measured using the Child Behavior Checklist. Results: The comparison group demonstrated a larger spatial negative priming effect (mean = 23.50, SD = 45.50) than the exposed group [mean = -6.84, SD = 86.39, F(1,50) = 5.91, p = 0.019, η2 = 0.11]. No difference in reported attention problems was found [F(1,51) = 1.63, p = 0.21, η2 = 0.03]. Neonatal abstinence syndrome and prenatal exposure to marijuana were found to predict slower saccade latencies in the exposed group (b = 54.55, SE = 23.56, p = 0.03 and b = 88.86, SE = 32.07, p = 0.01, respectively). Conclusion: Although exposed children did not appear to have attention deficits in daily life, lower performance on the SNP task indicates subtle alteration in the attention system.
Hiatal Hernia Mimicking ST Elevation Myocardial Infarction
Authors: Narala Karthiek , Banga Sandeep , Hsu Mark , Mungee Sudhir
Published: November 2014

A 72-year-old man with a history of hypertension, hiatal hernia, prostate cancer and lung cancer was admitted with complaints of abdominal pain, sweating and rigors. An electrocardiogram showed ST elevation in multiple leads. Noninvasive and invasive cardiovascular work-up was performed that was negative for occlusive coronary artery disease. Further studies demonstrated a large hiatal hernia; this was found to be the culprit causing his symptoms. Hiatal hernia is a very rare cause of ST segment elevation and should be considered in the differential diagnosis of disorders that can cause ST elevation.
Lipolysis, and Not Hepatic Lipogenesis, Is the Primary Modulator of Triglyceride Levels in Streptozotocin-Induced Diabetic Mice
Authors: Willecke Florian , Scerbo Diego , Nagareddy Prabhakara , Obunike Joseph C. , Barrett Tessa J. , Abdillahi Mariane L. , Trent Chad M. , Huggins Lesley A. , Fisher Edward A. , Drosatos Konstantinos , Goldberg Ira J.
Published: November 2014

Objective—

Diabetic hypertriglyceridemia is thought to be primarily driven by increased hepatic de novo lipogenesis. However, experiments in animal models indicated that insulin deficiency should decrease hepatic de novo lipogenesis and reduce plasma triglyceride levels.

Approach and Results—

To address the discrepancy between human data and genetically altered mouse models, we investigated whether insulin-deficient diabetic mice had triglyceride changes that resemble those in diabetic humans. Streptozotocin-induced insulin deficiency increased plasma triglyceride levels in mice. Contrary to the mouse models with impaired hepatic insulin receptor signaling, insulin deficiency did not reduce hepatic triglyceride secretion and de novo lipogenesis-related gene expression. Diabetic mice had a marked decrease in postprandial triglycerides clearance, which was associated with decreased lipoprotein lipase and peroxisome proliferator-activated receptor α mRNA levels in peripheral tissues and decreased lipoprotein lipase activity in skeletal muscle, heart, and brown adipose tissue. Diabetic heterozygous lipoprotein lipase knockout mice had markedly elevated fasting plasma triglyceride levels and prolonged postprandial triglycerides clearance.

Conclusions—

Insulin deficiency causes hypertriglyceridemia by decreasing peripheral lipolysis and not by an increase in hepatic triglycerides production and secretion.