bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Evaluation of SCS for AHTR and Time Assessment of Operation Procedures
Authors: Ogura Takahito , Nakata Junya , Mori Mititsugu , Sakashita Hiroto , Miwa Shuichiro
Published: November 2014

The Advanced High-Temperature Reactor (AHTR) is a new nuclear power reactor concept being investigated in some countries including the United States. The coolant is a liquid salt with a melting point of 460°C and a boiling point of 1430°C. The AHTR uses Silo Cooling System (SCS) as the decay heat removal system in a Beyond-Design-Basis Accident (BDBA). SCS has two accident mitigations. The first component is low-cost, and thick steel rings which conduct heating up the silo wall for BDBA. The second component is an annular ring of an inexpensive, solidified BDBA salt, which is heated from the bottom and melts when the temperature of the salt increases above the melting point, then flows into the silo, and floods the whole silo to its top level. SCS could make AHTR free from catastrophic accidents, where core melting or vessel failure never takes place since the BDBA salt near the top of silo passively absorbs decay heat. On the other hand, AHTR decreases its heat removal ability to avoid freezing of the salt and blocking the flow of the liquid when the temperatures are low. We performed the numerical calculation of AHTR heat removal system and evaluated whether it has the ability to remove decay heat with the robustness for a long-time cooling operation after BDBA. Furthermore, we need to build up and optimize the operation plan of SCS in AHTR, taking its thermal characteristics of this system into account. It is essential to avoid severe accidents which we can suppose as the possible catastrophic scenario.

In this paper, we calculated temperature distributions using the thermal-hydraulics code developed for AHTR, and assessed the performance in a long term cooling period under BDBA conditions. Finally, we investigated the temperature distributions of the whole plant, predicting the accident scenario without air-cooled passive decay heat-removal system. We obtained important conclusion about SCS of the AHTR that its heat removal ability was enough to avoid catastrophic accidents under Loss of Heat Sink (LOHS) conditions.
Influence of the Temperature History on Secondary Hydriding and Mechanical Properties of Zircaloy-4 Claddings: An Analysis of the QUENCH-LOCA Bundle Tests
Authors: Stuckert J. , Große M. , Rössger C. , Steinbrück M. , Walter M.
Published: November 2014

Two out-of-pile bundle tests, QUENCH-L0 and QUENCH-L1, were performed recently at Karlsruhe Institute of Technology (KIT) in the framework of the QUENCH-LOCA program devoted to the investigation of the so-called secondary hydriding of the cladding. The overall objective of this bundle test series is the investigation of ballooning, burst and secondary hydrogen uptake of the cladding under representative design basis accident conditions as well as detailed post-test investigation of cladding mechanical properties to analyze the material behavior with respect to embrittlement. The program was started in 2010 with the QUENCH-L0 commissioning test using 21 electrically heated rods with as-received Zircaloy-4 claddings followed in 2012 by the QUENCH-L1 reference test using the same material. These two tests differ in 1) heat-up rate during the first transient and 2) presence of a cool-down phase before quenching. The maximum heating rate reached during QUENCH-L0 was only 2.5 K/s, whereas the transient phase of QUENCH-L1 was performed with the maximum rate of 7 K/s. The state of the QUENCH-L0 bundle was practically “frozen” immediately after the transient phase by fast injection of two-phase fluid. The reference test QUENCH-L1, was performed with a typical cooling phase after the transient phase. It provides data on Zircaloy-4 cladding embrittlement based on more prototypical temperature history. Post-test neutron radiography and tomography revealed formation of hydrogen bands around the oxidized inner cladding surface in vicinity of the burst openings for both tests. However, the concentration of hydrogen absorbed inside these bands was different for both tests: whereas the maximum hydrogen concentration for QUENCH-L0 reached 2560 wppm, the corresponding value for QUENCH-L1 was only 1690 wppm. Complementary model calculations confirm that the differences in hydrogen concentrations are mainly related to the differences in temperature sequences. Subsequent tensile tests with tube segments at room temperature revealed the dependence of the mechanical behaviour on hydrogen concentration: tubes with hydrogen contents above 1500 wppm were simultaneously double ruptured along the hydrogen bands, whereas tubes with hydrogen concentrations below 1500 wppm failed at the middle of burst openings.
Modified Layer of Protection Analysis for Nuclear Safety Assessment
Authors: Gheyasi Seyed Mohsen , Pourgol-Mohammad Mohammad
Published: November 2014

Layer of Protection Analysis (LOPA) is extensively used for safety analysis of non-nuclear facilities e.g., chemical processes. It is simpler and less expensive methodology comparing full probabilistic risk assessment methods. It evaluates the probability of failure per demand for the safety system failures and the resulting consequences. LOPA is widely used in chemical process safety analysis however it is introduced as a practical technique for risk assessing in many other industries. This research examines utilization of LOPA method for nuclear systems as a quick evaluation of the safety level. The changes are proposed to classic LOPA method by using event tree method for event scenario identification and development. The so-called modified layer of protection analysis (Modified-LOPA) methodology utilizes Bayesian updating for more precise quantification of the failure probabilities and updating data. A simple example of a fire protection system shows application of this method.
ANDREA 2: Improved Version of Code for Reactor Core Analysis
Authors: Havlůj František , Vočka Radim , Vysoudil Jiří
Published: November 2014

In recent years, the core physics code ANDREA has been significantly improved and its capabilities were vastly extended. The code implementation has been overhauled to more modern, object-oriented and modular architecture. The code structure was adapted to allow use of multiple different neutronics solvers and to tackle various spatial and energy discretization models. The data library formats and processing workflow have been completely generalized, and different transport codes (e.g. HELIOS, SERPENT or SCALE) can be used to prepare several-group cross-section libraries for ANDREA. The new version of the code has gone through extensive validation both on the benchmarks and experimental data. The modular architecture of ANDREA code allow for its ongoing development. Currently we focus on coupling of ANDREA code with TRANSURANUS code.
Effects of Carbide Precipitate Formation on the Change in Ultrasonic Velocity in Austenitic Stainless Steels
Authors: Okita Taira , Etoh Junji , Sagisaka Mitsuyuki , Matsunaga Takashi , Isobe Yoshihiro
Published: November 2014

Ultrasonic tests were conducted for 304 type austenitic stainless steels with different annealing conditions and effects of carbide precipitate formation on the velocity changes were evaluated. The velocity increased with higher annealing temperature and/or longer annealing time. SEM observations indicated that carbide precipitates were formed mainly on grain boundaries. Results show that it is not the precipitation itself but the removal of carbon from the matrix that determines the velocity change.
CFD Simulation of Deflagration to Detonation Transition for Nuclear Safety
Authors: Hwang Eduardo , Ribeiro Felipe Porto , Su Jian
Published: November 2014

The present work aims to develop an efficient methodology for evaluating the Deflagration to Detonation Transition (DDT) in accidental scenarios from inherent hydrogen risk in water-cooled NPPs (Nuclear Power Plants). The physical problem is flame acceleration through a confined geometry congested with periodic obstacles, up to formation of a travelling shock wave. The problem was modeled by the Reynolds-averaged Navier-Stokes equations (RANS) with the standard k-ε turbulence model. There are two main combustion models: EDC (Eddy Dissipation Concept) whose equations are the transport equations for chemical species involved; and BVM (Burning Velocity Model) a transport equation for reaction progress (one scalar), to be used with three available turbulent flame speed correlations (Peters, Mueller and Zimont), and a new formulation based on Piston Action of the expanding burnt gas. The present work compared characteristics of these combustion models regarding flame acceleration in the midsize mc043 experiment, in order to apply the proposed combustion model in large scale DDT simulations. Experiment mc043 is consists of igniting a 12-meter long tube with 70 annular obstacles, filled with lean hydrogen-air mixture. The numerical results revealed that the proposed model is superior to BVM model correlations in predicting shock wave formation, and may provide a computationally more efficient option to the EDC model.
Time-Dependent, Three Dimensional Nodal Transport Code Development Based on Unstructured Mesh
Authors: He Mingtao , Wu Hongchun , Cao Liangzhi , Zheng Youqi , Zhou ShengCheng
Published: November 2014

A space-time nodal transport code, DAISY, was developed to evaluate dynamic neutron behavior in innovative nuclear system. The steady transport process is based on an arbitrary triangles-z mesh nodal method which can treat complicated geometry configuration with enough precision and acceptable calculated quantity. This code employs the improved quasi-static method for neutron kinetics with a predictor-corrector scheme to improve computational efficiency. The direct method and the point approximation for neutron kinetics are also implemented into DAISY to evaluate the precision and efficiency of this predictor-corrector scheme. This code was verified by several transient benchmarks. It shows that the predictor-corrector scheme in DAISY can greatly reduce the computational time with enough precision.
Experimental Study of the Cadmium Effects on Iodine Transport in the Primary Circuit During Severe Nuclear Accident
Authors: Gouëllo M. , Kalilainen J. , Rantanen P. , Kärkelä T. , Auvinen A.
Published: November 2014

In case of a severe accident in a light water reactor, iodine is one of the most important fission products in the context of reactor safety because of its significant total fuel inventory, high specific activity and radiotoxicity. Consequently, understanding its behavior under severe accident transient conditions is a major point in the optimization of the accident management and mitigation.

An experimental study has been launched at VTT investigating the behavior of iodine on primary circuit surfaces during a severe nuclear accident. The paper presents results obtained from the heating of metallic cadmium and caesium iodide in a crucible at temperature below 400°C under three different atmospheres. Aerosols and gaseous species released from the reaction crucible were sampled at 150°C on filters and liquid scrubbers and analyzed with HR-ICP-MS.

At first, experiments were conducted with one precursor (cadmium or caesium iodide). It was observed that cadmium is predominantly present as aerosol in all atmospheres but represents less than 1% of mass what has been recovered from the facility leaching. To the contrary, caesium iodide experiment showed that sampled iodine exists mainly as gaseous species.

By comparison to one-precursor studies, a change in the behavior of element was noticed when cadmium was added to caesium iodide. Different observations let to suggest a reaction between caesium iodide and cadmium in the crucible. The reaction would lead to the formation of compound made of cadmium and iodine in condensed phase below 150°C. More gaseous iodine was found from the sampling line with Ar/H2O/H2 atmosphere than in Ar/H2O atmosphere, suggesting that the cadmium is more reactive toward iodine in hydrogen-free atmosphere.
Current Implementation of the Quality Assurance Program at the United States Los Alamos National Laboratory
Authors: Van Valkenburg Taunia , Petru Ernie F. , Diepolder Paula R. , Sandquist Gary M.
Published: November 2014

The Los Alamos National Laboratory (LANL) is a one of the largest and diverse science and technological institutions in the world. The size and sophistication of LANL’s facilities and workforce present a unique challenge to develop and implement a Quality Assurance (QA) program that meets LANL’s needs. LANL has updated its QA Program to a targeted, requirements-based approach, and broadened its Quality Assurance technical expertise into essential technical areas. The expanded areas of expertise include engineering, project management, nuclear facility operations, and weapons design and fabrication. This approach is achieving success as evidenced on an institutional level by LANL’s receipt of various national, international and local awards for its products and services. Success is also realized on the QA Program level with sufficient recognition of the importance of the QA Program by the LANL workforce. However, QA program challenges remain in areas of expanding the importance of QA; streamlining the grading process and ensuring the program is commensurate with risk and customer expectations; maintaining sufficient authority and freedom from line management for deployed QA personnel while continuing to increase the technical breadth of QA personnel. These are the focus areas to continuously improve the LANL QA Program.
Nuclear-Coupled Thermal Hydraulics Stability of a Natural Circulation Lead-Cooled Fast Reactor
Authors: Lu Qiyue , Uddin Rizwan
Published: November 2014

Stability analyses are carried out for a natural circulation lead-cooled fast reactor which is at its design stage. Because of its natural circulation feature, flow stability as well as nuclear-coupled thermal hydraulics stability is of some concern. Modal Expansion Method (MEM) and Reduced Order Model (ROM) are used for neutronics and thermal hydraulics part, respectively. These two separate models are coupled through feedback effects. Different simulation scenarios on the separate and coupled models are reported.
Post-Fukushima Assessment of the AP1000® Plant
Authors: Schulz Terry L. , Kindred Thomas A. , Friedman Bryan N. , Glavin John E. , Malinowski Adam D. , Mathewson Phil A.
Published: November 2014

The AP1000 plant is an 1100-MWe class pressurized water reactor with passive safety features and extensive plant simplifications that enhance construction, operation, maintenance, and safety with reduced plant costs. The AP1000 passive nuclear power plant is uniquely equipped to withstand an extended station blackout scenario such as the events following the earthquake and tsunami at the Fukushima Daiichi nuclear power station without compromising core and containment integrity. Without AC power, using passive safety technology, the AP1000 plant provides cooling for the core, containment and spent fuel pool for more than 3 days without the need for operator actions. Following this passive coping period, minimal operator actions are needed to extend the operation of the passive features to 7 days using installed equipment. With the re-supply of fuel oil the coping time may be extended for an indefinite time. Connections for a few, small, easily transportable components provide a diverse backup means of extending passive system operation after the first 3 days. As a result, the AP1000 design provides very robust protection of public safety and the utility investment.

Following the accident at the Fukushima Dai-ichi nuclear power station in Japan, several initiatives were launched worldwide to assess the lessons learned. These include, but are not limited to, the European Nuclear Safety Regulators Group (ENSREG) stress tests, the Office for Nuclear Regulation (ONR) Final Report, the International Atomic Energy Agency (IAEA) Expert Mission Report, and the U.S. NRC Near-Term Task Force Recommendations. The AP1000 design has been assessed against these initiatives and lessons learned.

The purpose of this paper is to describe:

• How the accident at the Fukushima Dai-ichi nuclear power station was evaluated and translated into conclusions and recommendations for nuclear power plants worldwide

• How the AP1000 plant was evaluated in light of the recommendations resulting from the various post-Fukushima assessments

• The key conclusions resulting from the post-Fukushima evaluation of the AP1000 design
ÚJV Řež, a.s. Research Programme Supporting Development of Deep Geological Repository in the Czech Republic
Authors: Havlová Václava
Published: November 2014

ÚJV Řež, a.s. as a company with a long term experience in radioactive waste management (RWM) has been running a comprehensive research programme, supporting development of deep geological repository (DGR) in the Czech Republic.

Recently ÚJV Řež, a.s. research has focused on the different aspects of safety functions that DGR barriers should provide. Moreover, the research has also recently paid strong attention to real conditions that can be present in DGR (anaerobic reducing conditions, increased T due to heat generation by radioactive waste, contact of different materials within repository, real scale of the rock massive etc.). Both types of experiments, laboratory and in-situ experiments in underground laboratories, were included in the research programme. The presentation gives a brief overview of experimental trends, being conducted for materials and conditions, concerned in Czech repository concept.
External Event Risk Assessment: Methodology and Application
Authors: Lo Frano Rosa , Burgazzi Luciano
Published: November 2014

The 2011 Fukushima accident revealed various gaps related to probabilistic approach, used for the plant risk assessment against external events. In consideration of that and analysing the evolution of the accident scenario, some issues need to be re-considered and/or improved for a reliable NPP risk evaluation in Fukushima conditions.

This study is therefore aimed at the evaluation of the NPP safety performance when subjected to external events, such as the earthquake and/or tsunami (inundation phase), by applying the IDPSA (Integrated Deterministic Probabilistic Safety Analysis) approach, which combines the Probabilistic and Deterministic Safety Assessment ones.

To the purpose “stress tests” suggestions, presently foreseen by the European and International Associations, have been taken into account.

The main issues as emerging from the Fukushima accident, specifically the LOOP/SBO (Loss Of Offsite Power/Station Black Out) caused by a flooding or tsunami, were analysed. The results indicated that although the containment building is suffering local damaging, no loss of structural integrity occurs.
Study on Flow and Heat Transfer Characteristics of Different States of Water Under Natural Circulation
Authors: Ju Zhongyun , Zhou Tao , Li Jingjing , Xiao Zejun
Published: November 2014

Software CFX is used to build a typical natural circulation loop to study flow and heat transfer characteristics of water vapor, the vapor-liquid two-phase and supercritical water under natural circulation. During the process of natural circulation, the variation of parameters, heat transfer coefficient and mass flow is compared. It is found that when formed a natural circulation, the steam has a lower mass flow and heat transfer coefficient, while the two parameters of two-phase and supercritical water are higher. Indicates that the heat transfer capability of steam is weak, the steam cannot transfer heat out opportunely when serious accidents take place. The two-phase water is of high heat transfer coefficient. Supercritical water is of strong exchange capacity, supercritical water under natural circulation is a promising flow pattern.
Sensitivity Analysis of the Response of PWR Containment During a Loss of Coolant Accident Using RELAP5-3D and MELCOR
Authors: Vaghetto Rodolfo , Franklin Andrew , Vanni Alessandro , Hassan Yassin A.
Published: November 2014

The prediction of specific parameters for the reactor containment, such as pressure and sump pool temperature, is of paramount importance when studying the thermal-hydraulic phenomena involved in the debris generation, transport, and accumulation during Loss of Coolant Accidents (LOCA). The response of the reactor containment during these events may significantly vary depending of several factors such as break size and location, and other plant-specific features. When modeling the reactor and containment response using systems codes, the predictions may also depend on the selection of physical models, correlations and their coefficients. A sensitivity analysis of the response of a typical Pressurized Water Reactor (PWR) 4-loop reactor system and associated containment during a large break LOCA was conducted using RELAP5-3D and MELCOR to investigate the influence of geometrical parameters (break location), physical models (chiked flow models), and related coefficients (discharge coefficient at the break), on the containment response. The simulation results showed how the containment response changed by varying the selected parameters and confirmed the importance of identifying and studying the factors triggering the containment engineered features (containment sprays) when simulation the containment response.
Pressure Loss Coefficient of Spacer Grid for a Tight-Lattice Rod Bundle
Authors: In Wang-Kee , Shin Chang-Hwan , Kwack Young-Kyun , Lee Chi-Young , Oh Dong-Seok , Chun Tae-Hyun
Published: November 2014

Experimental and CFD (Computational Fluid Dynamics) analyses were conducted to determine the pressure loss coefficient of a spacer grid for a tight-lattice rod bundle simulating a dual-cooled annular fuel (DCAF) assembly. The DCAF is designed to have both internally and externally cooled channels by adopting annular pellet and dual claddings. The Korea Atomic Energy Research Institute proposed the DCAF assembly for the Korean optimum power reactor (OPR1000) which is a 12×12 square rod bundle with a rod pitch-to-diameter ratio (P/D) of 1.08. The pressure loss across the spacer grid specially designed for the 12×12 rod bundle is required in order to determine the inner to outer cooling channel flow split. Hence, the pressure drop of the spacer grid was measured using the full-size rod bundle for a Reynolds number ranging from 2e+04 to 2e+05. A CFD analysis was also performed to predict the pressure drop of the spacer grid used in the full-size bundle experiment. Only a single grid span of the test rod bundle was modeled in this CFD simulation. The grid loss coefficients by both the experiment and CFD analysis was shown to decrease as the Reynolds number increases. The measured loss coefficient was estimated from 1.30 to 1.50 for the normal operating condition of the reactor core with the DCAF, i.e., Re=3.5e+05. The CFD simulation predicted the grid loss coefficient being approximately 5% higher than the measured value.
Sensitivity Study on Turbulence Models for the Prediction of the Reactor Internal Flow
Authors: Lee Gong Hee , Bang Young Seok , Woo Sweng Woong , Cheong Ae Ju
Published: November 2014

In this study, in order to assess the prediction performance of Reynolds-averaged Navier-Stokes (RANS)-based turbulence models for the analysis of flow distribution inside the 1/5 scaled-down APR+ (Advanced Power Reactor Plus), the simulation was conducted with the commercial computational fluid dynamics software, ANSYS CFX R.13. The results predicted were then compared with the measured data. It was concluded that reactor internal-flow pattern differed locally; depending on the turbulence models used. In particular, the prediction performance of turbulence models showed the largest difference in the regions from the flow skirt to fuel assembly inlet. The prediction performance of the k-ε model was superior to other turbulence models. This model also predicted the relatively uniform distribution of core-inlet flow-rate.
Experimental Investigation of Nanotubes Utilization as a Nuclear Fuel Matrix Additive
Authors: Varmuza Jan , Katovsky Karel , Skalicka Jiri , Foral Stepan , Matejkova Jitka
Published: November 2014

Great operational challenges are placed on nuclear power plants. These challenges are usually reflected in the expansion of fuel cycle length, long-time operation or power uprates. The one way is to optimize the equipment or replace it with equipment with higher efficiency. The second way is to optimize the fuel and its cladding. In this area it is possible to work mainly on the development of new materials which have better nuclear or mechanical properties.

Nuclear power industry is a conservative one. It is necessary to have a detailed knowledge of materials properties of used equipment. Knowledge of the materials behavior is particularly required in the environment where the materials are exposed to neutron flux. This article focuses on new promising materials that can be used in a nuclear fuel, a nuclear reactor or its closest vicinity. Carbon nano materials can be included among these types of materials. Composite materials have generally improved mechanical and thermal properties with addition of nanoparticles. However the additives itself have an impact on the behavior of the neutron field.

This article describes an experiment that examined the behavior of neutrons in carbon nano fibers, carbon nano tubes and nano wires of aluminum oxide. The main goal of the experiment was to determine how neutron scattering is affected, when the sample is exposed to neutron beam. The article presents results, including additional testing of nano materials. Additional tests were carried out to verify the purity and parameters of the investigated samples.
Cross-sectional atomic force microscope in scanning electron microscope
Authors: Park Byong Chon , Song Woon , Hyun Kim Dal , Lee Ju-Yeop , Hong Jaewan , Seung Kim Jin
Published: November 2014

A newly designed atomic force microscope (referred to as “cross-sectional AFM” or “xAFM”) is demonstrated that enables tip–sample interactions to be studied directly from a cross-sectional scanning electron microscope (SEM) view during AFM operation. Previously, such interactions have only been modeled using computer simulations or sensor-generating data. The xAFM will allow researchers to acquire additional visual information not available with conventional microscopic techniques. The xAFM is operated in a tungsten filament SEM, by examining a grating sample that is cleaved and mounted on the sample scanner so that the cleaved cross section faces upwards toward the bottom of the electron column. The tip scans horizontally, parallel to and at a height slightly lower than the cross-sectional surface of the sample but within the depth of focus of the SEM. Three experiments are described that show the unique features of the xAFM. The first demonstrates direct observation of the “tip-convolution” in real-time SEM images. The second shows unambiguous identification of an artifact in the lateral force microscope, from which a “double dip” appears in the signal from a damaged tip in a backward scan of the grating surface. The third enables measurements from blurred SEM images of large-amplitude oscillating high-Q AFM cantilevers in vacuum.
Highly Dynamic Genomic Loci Drive the Synthesis of Two Types of Capsular or Secreted Polysaccharides within the Mycoplasma mycoides Cluster
Authors: Bertin Clothilde , Pau-Roblot Corinne , Courtois Josiane , Manso-Silván Lucía , Tardy Florence , Poumarat François , Citti Christine , Sirand-Pugnet Pascal , Gaurivaud Patrice , Thiaucourt François
Published: November 2014

Mycoplasmas of the
Mycoplasma mycoides
cluster are all ruminant pathogens.
Mycoplasma mycoides
subsp.
mycoides
is responsible for contagious bovine pleuropneumonia and is known to produce capsular polysaccharide (CPS) and exopolysaccharide (EPS). Previous studies have strongly suggested a role for
Mycoplasma mycoides
subsp.
mycoides
polysaccharides in pathogenicity.
Mycoplasma mycoides
subsp.
mycoides
-secreted EPS was recently characterized as a β(1→6)-galactofuranose homopolymer (galactan) identical to the capsular product. Here, we extended the characterization of secreted polysaccharides to all other members of the
M. mycoides
cluster:
M. capricolum
subsp.
capripneumoniae
,
M. capricolum
subsp.
capricolum
,
M. leachii
, and
M. mycoides
subsp.
capri
(including the LC and Capri serovars). Extracted EPS was characterized by nuclear magnetic resonance, resulting in the identification of a homopolymer of β(1→2)-glucopyranose (glucan) in
M. capricolum
subsp.
capripneumoniae
and
M. leachii
. Monoclonal antibodies specific for this glucan and for the
Mycoplasma mycoides
subsp.
mycoides
-secreted galactan were used to detect the two polysaccharides. While
M. mycoides
subsp.
capri
strains of serovar LC produced only capsular galactan, no polysaccharide could be detected in strains of serovar Capri. All strains of
M. capricolum
subsp.
capripneumoniae
and
M. leachii
produced glucan CPS and EPS, whereas glucan production and localization varied among
M. capricolum
subsp.
capricolum
strains. Genes associated with polysaccharide synthesis and forming a biosynthetic pathway were predicted in all cluster members. These genes were organized in clusters within two loci representing genetic variability hot spots. Phylogenetic analysis showed that some of these genes, notably
galE
and
glf
, were acquired via horizontal gene transfer. These findings call for a reassessment of the specificity of the serological tests based on mycoplasma polysaccharides.
Ecological Succession and Viability of Human-Associated Microbiota on Restroom Surfaces
Authors: Gibbons Sean M. , Schwartz Tara , Fouquier Jennifer , Mitchell Michelle , Sangwan Naseer , Gilbert Jack A. , Kelley Scott T.
Published: November 2014

Human-associated bacteria dominate the built environment (BE). Following decontamination of floors, toilet seats, and soap dispensers in four public restrooms,
in situ
bacterial communities were characterized hourly, daily, and weekly to determine their successional ecology. The viability of cultivable bacteria, following the removal of dispersal agents (humans), was also assessed hourly. A late-successional community developed within 5 to 8 h on restroom floors and showed remarkable stability over weeks to months. Despite late-successional dominance by skin- and outdoor-associated bacteria, the most ubiquitous organisms were predominantly gut-associated taxa, which persisted following exclusion of humans.
Staphylococcus
represented the majority of the cultivable community, even after several hours of human exclusion. Methicillin-resistant
Staphylococcus aureus
(MRSA)-associated virulence genes were found on floors but were not present in assembled
Staphylococcus
pan-genomes. Viral abundances, which were predominantly enterophages, human papilloma virus, and herpesviruses, were significantly correlated with bacterial abundances and showed an unexpectedly low virus-to-bacterium ratio in surface-associated samples, suggesting that bacterial hosts are mostly dormant on BE surfaces.
Association of Biodiversity with the Rates of Micropollutant Biotransformations among Full-Scale Wastewater Treatment Plant Communities
Authors: Johnson David R. , Helbling Damian E. , Lee Tae Kwon , Park Joonhong , Fenner Kathrin , Kohler Hans-Peter E. , Ackermann Martin
Published: November 2014

Biodiversities can differ substantially among different wastewater treatment plant (WWTP) communities. Whether differences in biodiversity translate into differences in the provision of particular ecosystem services, however, is under active debate. Theoretical considerations predict that WWTP communities with more biodiversity are more likely to contain strains that have positive effects on the rates of particular ecosystem functions, thus resulting in positive associations between those two variables. However, if WWTP communities were sufficiently biodiverse to nearly saturate the set of possible positive effects, then positive associations would not occur between biodiversity and the rates of particular ecosystem functions. To test these expectations, we measured the taxonomic biodiversity, functional biodiversity, and rates of 10 different micropollutant biotransformations for 10 full-scale WWTP communities. We have demonstrated that biodiversity is positively associated with the rates of specific, but not all, micropollutant biotransformations. Thus, one cannot assume whether or how biodiversity will associate with the rate of any particular micropollutant biotransformation. We have further demonstrated that the strongest positive association is between biodiversity and the collective rate of multiple micropollutant biotransformations. Thus, more biodiversity is likely required to maximize the collective rates of multiple micropollutant biotransformations than is required to maximize the rate of any individual micropollutant biotransformation. We finally provide evidence that the positive associations are stronger for rare micropollutant biotransformations than for common micropollutant biotransformations. Together, our results are consistent with the hypothesis that differences in biodiversity can indeed translate into differences in the provision of particular ecosystem services by full-scale WWTP communities.
Risk factors for long-bone fractures in children up to 5 years of age: a nested case–control study
Authors: Baker Ruth , Orton Elizabeth , Tata Laila J , Kendrick Denise
Published: November 2014

Aim

To investigate risk factors for first long-bone fractures in children up to 5 years old in order to provide evidence about which families could benefit from injury prevention interventions.

Methods

Population-based matched nested case–control study using The Health Improvement Network, a UK primary care research database, 1988–2004.

Maternal, household and child risk factors for injury were assessed among 2456 children with long-bone fractures (cases). 23 661controls were matched to cases on general practice. Adjusted ORs and 95% CIs were estimated using conditional logistic regression.

Results

Fractures of long-bones were independently associated with younger maternal age and higher birth order, with children who were the fourth-born in the family, or later, having a threefold greater odds of fracture compared to first-born children (adjusted OR 3.12, 95% CI 2.08 to 4.68). Children over the age of 1 year had a fourfold (13–24 months, adjusted OR 4.09 95% CI 3.51 to 4.76) to fivefold (37+ months, adjusted OR 4.88 95% CI 4.21 to 5.66) increase in the odds of a long-bone fracture compared to children aged 0–12 months. Children in families with a history of maternal alcohol misuse had a raised odds of long-bone fracture (adjusted OR 2.33, 95% CI 1.13 to 4.82) compared to those with no documented history.

Conclusions

Risk factors for long-bone fractures in children less than 5 years old included age above 1 year, increasing birth order, younger maternal age and maternal alcohol misuse. These risk factors should be used to prioritise families and communities for injury prevention interventions.
Trends and patterns of hormonal contraceptive prescribing for adolescents in primary care in the UK
Authors: Rashed Asia N , Hsia Yingfen , Wilton Lynda , Ziller May , Kostev Karel , Tomlin Stephen
Published: November 2014

Background

Hormonal contraceptives are the most common method used worldwide by teenagers to prevent unwanted pregnancies. To date there are limited data about such use by teenagers in the UK. This study investigated trends and patterns of hormonal contraceptive prescribing to adolescents aged 12–18 years in UK primary care between 2002 and 2011.

Methods

A retrospective cohort study using the IMS Disease Analyzer database was conducted. All females aged 12–18 years with ≥1 prescription for a contraceptive drug between 1 January 2002 and 31 December 2011 were included. Annual prevalence of contraceptive drug prescribing was calculated, and indications for prescribing, and types of contraceptive drug prescribed, were examined.

Results

In 2002, 13.7% (6135/44 532) of female adolescents received prescriptions for hormonal contraceptives, compared to 19.0% (6597/34 676) in 2011. The majority of female adolescents [2002: 76.2% (4676/6135); 2011: 65.7% (4334/6597)] received a contraceptive drug for ‘contraceptive management’. The combined oral contraceptive (COC), ‘progestogen+estrogen’, was the most commonly prescribed. Although use of progestogen-only contraceptives was lower than COCs, the number of patients who received desogestrel pills and etonogestrel implants increased during the study period; levonorgestrel pill use declined. Only one injectable progestogen, long-acting depot medroxyprogesterone acetate, was prescribed.

Conclusions

Use of hormonal contraceptives among adolescents increased between 2002 and 2011, and COC usage was dominant. The increasing use of hormonal contraceptives in adolescents, especially in younger adolescents, warrants further investigation, including research into the long-term safety of these medicines in this age group.
Patients with systemic lupus erythematosus and haematological malignancy at a tertiary care centre: timing, histopathology and therapy
Authors: Knight Jason S , Blayney Douglas W , Somers Emily C
Published: November 2014

Objectives

Patients with systemic lupus erythematosus (SLE) are at higher risk of haematological malignancies (HMs) than the general population. Most reports have focused on HM diagnosed after SLE, and have excluded concurrent and preceding diagnoses. Information on response to therapy is also limited.

Methods

We identified 13 296 cases of HM and 10 539 potential patients with SLE at our centre; 45 patients were confirmed to have HM and SLE. Our retrospective case series was based on these 45 patients.

Results

Of the 45 patients, 64% were diagnosed with HM ≥1 yearafterdiagnosis with SLE, and 36% with HMbefore or concurrent withSLE. Of the 29 patients with HM after SLE, 13 had diffuse large B cell lymphoma (DLBCL), 6 indolent lymphoma, 4 leukaemia, 3 Hodgkin's disease, and 1 each Burkitt's lymphoma, T cell lymphoma and multiple myeloma. Eleven patients with DLBCL were treated with cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone (CHOP) or rituximab-CHOP; hydroxydaunorubicin, oncovin and prednisone; only four achieved durable remission. Of the 16 patients diagnosed with HM before or concurrent with SLE, 9 were diagnosed with HM more than 2 years before SLE and tended to be in remission prior to SLE diagnosis. Seven patients were diagnosed with HM and SLE concurrently; in terms of their HM, six achieved remission or stable disease.

Conclusions

In summary, DLBCL was the most common type of lymphoma in patients diagnosed with HM after SLE; these patients presented with advanced-stage disease and had poor outcomes. In contrast, patients diagnosed with HM before or concurrent with SLE had early stage disease and typically achieved remission.
Diet and sex modify exercise and cardiac adaptation in the mouse
Authors: Konhilas John P. , Chen Hao , Luczak Elizabeth , McKee Laurel A. , Regan Jessica , Watson Peter A. , Stauffer Brian L. , Khalpey Zain I , Mckinsey Timothy A. , Horn Todd , LaFleur Bonnie , Leinwand Leslie A.
Published: November 2014

The heart adapts to exercise stimuli in a sex-dimorphic manner when mice are fed the traditional soy-based chow. Females undergo more voluntary exercise (4 wk) than males and exhibit more cardiac hypertrophy per kilometer run (18, 32). We have found that diet plays a critical role in cage wheel exercise and cardiac adaptation to the exercise stimulus in this sex dimorphism. Specifically, feeding male mice a casein-based, soy-free diet increases daily running distance over soy-fed counterparts to equal that of females. Moreover, casein-fed males have a greater capacity to increase their cardiac mass in response to exercise compared with soy-fed males. To further explore the biochemical mechanisms for these differences, we performed a candidate-based RT-PCR screen on genes previously implicated in diet- or exercise-based cardiac hypertrophy. Of the genes screened, many exhibit significant exercise, diet, or sex effects but only transforming growth factor-β1 shows a significant three-way interaction with no genes showing a two-way interaction. Finally, we show that the expression and activity of adenosine monophosphate-activated kinase-α2 and acetyl-CoA carboxylase is dependent on exercise, diet, and sex.
Intracellular Osteopontin Inhibits Toll-like Receptor Signaling and Impedes Liver Carcinogenesis
Authors: Fan Xiaoyu , He Chunyan , Jing Wei , Zhou Xuyu , Chen Rui , Cao Lei , Zhu Minhui , Jia Rongjie , Wang Hao , Guo Yajun , Zhao Jian
Published: November 2014

Osteopontin (OPN) has been implicated widely in tumor growth and metastasis, but the range of its contributions is not yet fully understood. In this study, we show that genetic ablation of Opn in mice sensitizes them to diethylnitrosamine (DEN)-induced hepatocarcinogenesis. Opn-deficient mice (Opn−/− mice) exhibited enhanced production of proinflammatory cytokines and compensatory proliferation. Administering OPN antibody or recombinant OPN protein to wild-type or Opn−/− mice-derived macrophages, respectively, had little effect on cytokine production. In contrast, overexpression of intracellular OPN (iOPN) in Opn-deficient macrophages strongly suppressed production of proinflammatory cytokines. In addition, we found that iOPN was able to interact with the pivotal Toll-like receptor (TLR) signaling protein MyD88 in macrophages after stimulation with cellular debris, thereby disrupting TLR signaling in macrophages. Our results indicated that iOPN was capable of functioning as an endogenous negative regulator of TLR-mediated immune responses, acting to ameliorate production of proinflammatory cytokines and curtail DEN-induced hepatocarcinogenesis. Together, our results expand the important role of OPN in inflammation-associated cancers and deepen its relevance for novel treatment strategies in liver cancer. Cancer Res; 75(1); 86–97. ©2014 AACR.
PLK1 Phosphorylates PAX3-FOXO1, the Inhibition of Which Triggers Regression of Alveolar Rhabdomyosarcoma
Authors: Thalhammer Verena , Lopez-Garcia Laura A. , Herrero-Martin David , Hecker Regina , Laubscher Dominik , Gierisch Maria E. , Wachtel Marco , Bode Peter , Nanni Paolo , Blank Bernd , Koscielniak Ewa , Schäfer Beat W.
Published: November 2014

Pediatric tumors harbor very low numbers of somatic mutations and therefore offer few targets to improve therapeutic management with targeted drugs. In particular, outcomes remain dismal for patients with metastatic alveolar rhabdomyosarcoma (aRMS), where the chimeric transcription factor PAX3/7-FOXO1 has been implicated but problematic to target. In this report, we addressed this challenge by developing a two-armed screen for druggable upstream regulatory kinases in the PAX3/7-FOXO1 pathway. Screening libraries of kinome siRNA and small molecules, we defined PLK1 as an upstream-acting regulator. Mechanistically, PLK1 interacted with and phosphorylated PAX3-FOXO1 at the novel site S503, leading to protein stabilization. Notably, PLK1 inhibition led to elevated ubiquitination and rapid proteasomal degradation of the PAX3-FOXO1 chimeric oncoprotein. On this basis, we embarked on a preclinical validation of PLK1 as a target in a xenograft mouse model of aRMS, where the PLK1 inhibitor BI 2536 reduced PAX3-FOXO1–mediated gene expression and elicited tumor regression. Clinically, analysis of human aRMS tumor biopsies documented high PLK1 expression to offer prognostic significance for both event-free survival and overall survival. Taken together, these preclinical studies validate the PLK1–PAX3-FOXO1 axis as a rational target to treat aRMS. Cancer Res; 75(1); 98–110. ©2014 AACR.
Acute Targeting of General Transcription Factor IIB Restricts Cardiac Hypertrophy via Selective Inhibition of Gene Transcription
Authors: Sayed Danish , Yang Zhi , He Minzhen , Pfleger Jessica M. , Abdellatif Maha
Published: November 2014

Background—

We previously reported that specialized and housekeeping genes are differentially regulated via de novo recruitment and pause-release of RNA polymerase II, respectively, during cardiac hypertrophy. However, the significance of this finding remains to be examined. Therefore, the purpose of this study was to determine the mechanisms that differentially regulate these gene groups and exploit them for therapeutic targeting.

Methods and Results—

Here, we show that general transcription factor IIB (TFIIB) and cyclin-dependent kinase 9 are upregulated during hypertrophy, both targeted by microRNA-1, and play preferential roles in regulating those 2 groups of genes. Chromatin immunoprecipitation-sequencing reveals that TFIIB is constitutively bound to all paused, housekeeping, promoters, whereas de novo recruitment of TFIIB and polymerase II is required for specialized genes that are induced during hypertrophy. We exploited this dichotomy to acutely inhibit induction of the latter set, which encompasses cardiomyopathy, immune reaction, and extracellular matrix genes, using locked nucleic acid–modified antisense TFIIB oligonucleotide treatment. This resulted in suppression of all specialized genes, while sparing the housekeeping ones, and, thus, attenuated pathological hypertrophy.

Conclusions—

The data for the first time reveal distinct general TFIIB dynamics that regulate specialized versus housekeeping genes during cardiac hypertrophy. Thus, by acutely targeting TFIIB, we were able to inhibit selectively the former set of genes and ameliorate pressure overload hypertrophy. We also demonstrate the feasibility of acutely and reversibly targeting cardiac mRNA for therapeutic purposes using locked nucleic acid–modified antisense oligonucleotides.
Socioeconomic Inequalities in Quality of Care and Outcomes Among Patients With Acute Coronary Syndrome in the Modern Era of Drug Eluting Stents
Authors: Yong Celina M. , Abnousi Freddy , Asch Steven M. , Heidenreich Paul A.
Published: November 2014

Background

The rapidly changing landscape of percutaneous coronary intervention provides a unique model for examining disparities over time. Previous studies have not examined socioeconomic inequalities in the current era of drug eluting stents (
DES
).

Methods and Results

We analyzed 835 070 hospitalizations for acute coronary syndrome (
ACS
) from the Healthcare Cost and Utilization Project across all insurance types from 2008 to 2011, examining whether quality of care and outcomes for patients with
ACS
differed by income (based on zip code of residence) with adjustment for patient characteristics and clustering by hospital. We found that lower‐income patients were less likely to receive an angiogram within 24 hours of a
ST
elevation myocardial infarction (
STEMI
) (69.5% for
IQ
1 versus 73.7% for
IQ
4,
P
<0.0001,
OR
0.79 [0.68 to 0.91]) or within 48 hours of a Non‐
STEMI
(47.6% for
IQ
1 versus 51.8% for
IQ
4,
P
<0.0001,
OR
0.86 [0.75 to 0.99]). Lower income was associated with less use of a
DES
(64.7% for
IQ
1 versus 71.2% for
IQ
4,
P
<0.0001,
OR
0.83 [0.74 to 0.93]). However, no differences were found for coronary artery bypass surgery. Among
STEMI
patients, lower‐income patients also had slightly increased adjusted mortality rates (10.8% for
IQ
1 versus 9.4% for
IQ
4,
P
<0.0001,
OR
1.17 [1.11 to 1.25]). After further adjusting for time to reperfusion among
STEMI
patients, mortality differences across income groups decreased.

Conclusions

For the most well accepted procedural treatments for
ACS
, income inequalities have faded. However, such inequalities have persisted for
DES
use, a relatively expensive and until recently, controversial revascularization procedure. Differences in mortality are significantly associated with differences in time to primary
PCI
, suggesting an important target for understanding why these inequalities persist.