bluuebunny/crossref_metadata_2025 huggingface dataset:
Failure Analysis Prediction Versus Industry Failure Experience of Air Operated Valves in the Nuclear Industry
Authors: Ezekoye L. Ike
Published: December 2016

Safety related valves in the nuclear industry are designed to meet the requirements of the design specifications for the systems in which they are to be installed. In developing valve specifications, systems and valve engineers collaborate to craft the essential requirements needed to support the procurement of the valves that meet the design requirements, and thereby provide reliable service during plant life. The specification requirements, together with the ASME Boiler and Pressure Vessel Code and Standards, provide a strong basis for assuring both structural integrity and functionality of the valve assemblies.

The functional requirements cover the duties of the valves. As these valves are safety related, they are generally subjected to preoperational testing and possibly additional qualification testing during manufacture, to ensure that the valves can perform their safety related functions in service. The nuclear experience of engineered products such as valves shows that considerable amount of analysis and documentation of component stresses are performed to ensure compliance with the ASME code and specification requirements.

The ASME Code requirements, together with the normal controls applied during manufacture of safety related valves, enhance the reliability of the valves. However, valve failures still occur during plant operation. In this paper, the failures of air operated valves (AOVs) used in nuclear applications were reviewed and the data compared against the failures predicted by valve suppliers based on weak link analysis of the valves. The study shows that there are significant differences between what the suppliers consider structurally likely to fail, what the purchaser expects to fail, and what really fails from field experience. The study shows that field failures are complex. They can be initiated by many factors, most of which are not obvious and cannot be controlled by the valve designer. The complexity of field failures of air operated valves is discussed in this paper.
Numerical Simulation of CFRP Reinforced Steel Pipe Elbows Subjected to Cyclic Loading
Authors: Chatzopoulou Giannoula , Skarakis Ioannis , Karamanos Spyros A. , Tsouvalis Nicholas G. , Pournara Aglaia E.
Published: December 2016

Strengthening of pipelines and piping systems under extreme loading conditions increases their operation safety level towards safeguarding their structural integrity. Motivated by the structural integrity of pipelines and piping systems, the present study aims at investigating the effect of Carbon Fiber Reinforced Plastic (CFRP) wrapping on the mechanical response of cyclically-loaded steel pipe elbows. Based on experimental testing results, a finite element model is developed, which simulates reinforced and non-reinforced pipe elbows specimens subjected to low-cyclic fatigue. For the description of the material nonlinearities, an efficient cyclic-plasticity material model is also employed, capable of describing both the yield plateau region of the steel stress-strain curve and the Bauschinger effect that appears under reverse plastic loading conditions. The results from the numerical models are compared successfully with the experimental data. Furthermore, a parametric analysis is conducted in order to examine the effect of internal pressure on the structural behavior of unreinforced and reinforced elbows, subjected to cyclic loading.
Emergency Core Cooling System Sump Strainer Fibre Bypass Testing and Measurement
Authors: Cheng Qingwu , Adams Harry , Yetisir Metin
Published: December 2016

The potential of losing post-Loss Of Coolant Accident (LOCA) recirculation capability due to debris blockage of Emergency Core Cooling (ECC) strainers resulted in early replacements of ECC strainers in most nuclear power plants. To validate the performance of ECC strainers, extensive testing representing plant conditions is required. Such testing programs include thin-bed and full debris load pressure drop tests, fibre bypass tests and chemical effects tests. Multiple testing loops and state-of-the-art analysis techniques have provided in-depth understanding of sump strainer performance and the effect of chemical precipitation on debris bed head loss.

ECC strainers typically use perforated plates as filtering surfaces with 1.6 to 2.5 mm holes and 35 to 40% open area, allowing some particulates and fibres to pass through the strainer filtering surfaces. Recently, the bypassed fibrous debris has been identified as a potential safety concern due to its possible deposition in the reactor core and blocking of flow into fuel assemblies. In some cases, the amount of fibre that is specified as allowed to enter a reactor core is only 15 g per fuel assembly for pressurized water reactors. Characterization and quantification of bypassed fibre debris for nuclear power plants are needed to address regulatory requirements. Testing methodology and analysis techniques to address regulatory requirements and concerns are presented in this paper. In particular, a newly developed technique is presented to address debris bypass quantification.
Three-Dimensional Finite Element Analyses of Compact Tension Specimens of Irradiated Zr-2.5Nb Materials Using Submodeling
Authors: Sung Shin-Jang , Pan Jwo , Lam Poh-Sang , Scarth Douglas A.
Published: December 2016

In this paper, the crack tip stresses along the front of a crack in a compact tension (CT) specimen of irradiated Zr-2.5Nb material are investigated by three-dimensional finite element analyses using the submodeling technique. A parametric study on two-dimensional submodeling of a CT specimen was first conducted to determine the appropriate mesh near the crack tip of a global model and the appropriate size of a submodel. The results show that the collapsed elements should be used near the crack tip in a global model and the region of a submodel should at least enclose the plastic zone to achieve acceptable results. With the submodeling strategy, a three-dimensional finite element analysis of the CT specimen is conducted. The distributions of the opening stress and out-of-plane normal stress ahead of the front of a crack in the CT specimen are obtained. Based on the computational results with the hydride fracture stress of 750 MPa for both radial and circumferential hydrides, all radial hydrides ahead of the crack front and the circumferential hydrides in the middle portion of the specimen should fracture at the specimen load of 3,000 N. Circumferential hydrides near the free surfaces do not fracture and the size of the zone without fractured circumferential hydrides increases with the increasing radial distance to the crack front. The computational results also show the three-dimensional effects on the variation of the plastic zone size and shape along the crack front, that is different from the conventional understanding of a dog-bone shape where the plastic zone on the free surface follows that under plane stress conditions and the plastic zone near the middle portion of the crack front follows that under plane strain conditions.
Three-Dimensional Finite Element Analyses of Thin-Sliced Compact Tension Specimens of Irradiated Zr-2.5Nb Materials With Consideration of Split Circumferential Hydrides
Authors: Sung Shin-Jang , Pan Jwo , Lam Poh-Sang , Scarth Douglas A.
Published: December 2016

In this paper, the low energy mode associated with split circumferential hydrides is examined by conducting three-dimensional finite element analyses of thin-sliced compact tension (CT) specimens of irradiated Zr-2.5Nb materials with split circumferential hydrides. Finite element models of thin-sliced CT specimens with split circumferential hydrides and various slice thicknesses are developed with the assumption of the plane strain condition in the thickness direction except in the split circumferential hydride regions. The computational results indicate that with split circumferential hydrides, the crack tip opening displacement (CTOD) can increase 50% for thinner thin-sliced specimens under the same load per unit thickness. With the use of a strain-based failure criterion with split circumferential hydrides, the load per unit thickness for thinner thin-sliced specimens can reduce by at most 70% to meet the failure criterion.
Undertaking Bolted Joint Integrity Management: Getting to Zero Leaks Quickly and Effectively
Authors: Kaye Alwyn
Published: December 2016

Leaks can and are being eliminated in a wide array of industries. There is a sweeping change across all the oil and gas, chemical and petrochemical and many related industries and businesses that use pressure equipment. This reflects social change and ever increasing demands for safe and reliable pressure equipment performance. No longer are leaks considered acceptable or the normal course of business. Codes, standards and specifications globally are changing and improving to reflect the need for improved performance. The implementation by individuals and organisations to follow this important drive to zero leaks has been hindered by fragmented guidance and misunderstanding of the plethora of options presented in the marketplace.

In industries that need to demonstrate performance, reliability and compliance, the need to create the structure and platform to make this successful has never been more pressing than it is now. Transformation of plant and equipment from normalized deviance and tolerance of leaks and failures to improved reliability is not only possible but essential in a world of resolve to cost containment and environmental protection.

This paper demonstrates the viability and importance of this change in philosophy followed by action. Examples are provided of the methodology of review and analysis through calculation followed by application. These must come together with basic plant operation in a comprehensive program of changed values and beliefs in order to be successful in the outcome. How to put it all together, is discussed and described. The paper authenticates the issues and describes the approaches needed by using case studies to demonstrate the principles and techniques needed to achieve success in implementation. It is understood that some minor modifications based on end user situations and needs may require adaptation or adjustment of some details. However the principles outlined are in keeping with and closely follow the intent and adherence to the European Standards EN-1591 and ASME Post-Construction Committee ASME PCC-1 “Guidelines for Pressure Boundary Bolted Joint Assembly”. [1,2]
Flaw Stability Analysis of Semi-Elliptical Surface Cracks in Canisters Under the Influence of Welding Residual Stress
Authors: Shi Jinhua , Wei Liwu , Lam Poh-Sang
Published: December 2016

Many stainless steel canisters for the dry storage of spent nuclear fuel are located in coastal regions. Because the heat treatment for relieving the welding residual stress is not required during fabrication, these canisters may be susceptible to chloride induced stress corrosion cracking due to the deliquescence of chloride-bearing marine salts or dust that enter the overpack system and deposit on the canister external surface. The NDE techniques and the associated delivery system are being developed to conduct periodic inservice inspections. The acceptance standards are needed to disposition findings should flaw-like indications be found. The instability crack lengths and depths for these flaws in the form of semi-elliptical shape near the welds are determined with R6 procedure. The cracks are subject to the canister design pressure and handling loads as well as the estimated welding residual stresses.
Experimental Investigation of Resonant Coupling Between Turbulent Flow Past a Rectangular Cavity and a Standing Gravity Wave
Authors: Reaume Jonathan , Oshkai Peter
Published: December 2016

Coupling between self-excited oscillations of turbulent flow of water in an open channel along the opening of a rectangular cavity and the standing gravity wave in the cavity was investigated experimentally for a range of inflow velocities and characteristic depths of the water. The objective of the current investigation is to examine the effect of water depth on the onset of fully coupled oscillations of the shear flow past the cavity. Video recording of the oscillating free-surface inside the resonator cavity in conjunction with free-surface elevation measurements using a capacitive wave gauge provided representation of the resonant wave modes of the cavity as well as the degree of the flow-wave coupling in terms of the amplitude and the quality factor of the associated spectral peak. Moreover, application of digital particle image velocimetry (PIV) provided insight into the evolution of the vortical structures that formed across the cavity opening. Coherent oscillations were attainable for a wide range of water depths. Variation of the water depth affected the degree of coupling between the shear layer oscillations and the gravity wave as well as the three-dimensionality of the flow structure.
Validation of FE Analysis Using a Test to Destruction Experiment for a Vessel Post Weld Heat Treatment Stand
Authors: Slee Adam J. , Stevenson Alan , Pellereau Ben , Holbourn John , Wright Keith
Published: December 2016

This paper details the methodology of validating a furnace heat treatment stand subjected to elevated temperatures using Finite Element Analysis (FEA). An initial heat treatment stand was designed for use with a superfluous vessel, which was then analysed and validated with a tested to destruction experiment. A revised design of heat treatment stand was then developed for Post Weld Heat Treatment (PWHT) of an actual vessel, supported by the validated analysis methodology.

A 3D model of each stand was created in Abaqus using shell elements for the beam and plate sections, and spring elements for bolts. This analysis incorporated a full contact model to correctly capture the flexural characteristics of the individual components during loading of the stand. An elastic-perfectly-plastic Limit Load Analysis (LLA) was initially used to determine the expected plastic collapse load for both designs of stand at a range of temperatures. This was followed by a buckling analysis to capture how susceptible the stand was to elastic structural instability. In order to determine the sensitivity of the structures to buckling, initial elastic imperfections were seeded into a post buckling LLA; other sensitivity studies included centre of gravity offset and consideration of creep.

The test to destruction of the stand has provided validation for the analysis methodology. The analysis of the revised design has shown acceptable margin exists at PWHT temperatures.
A Systematic Approach to Re-Using of Used or Out-of-Service Static Equipment
Authors: Ebrahimi Kaveh
Published: December 2016

The constant uncertainty within the hydrocarbon production and refining market coupled with the continued pressure to reduce greenhouse gas emissions and costs is increasing the need for operators of petroleum facilities to seek cost-effective ways of utilizing used or out-of-service equipment instead of installing new equipment. As an example, there may be equipment in parts of a refinery that have been out of service for a while, which the operator or end user would like to use in similar applications in the same refinery or other plants elsewhere.

Once an operator decides to look at the possibility of re-using used or out-of-service equipment, a few important steps need to be taken to determine whether the equipment is still operable and suitable for its new intended service. As inspection, moving or relocating of major equipment within operating plants is usually possible only during planned turnarounds, the correct identification of necessary steps, prioritizing of tasks, and precise planning and coordination of activities to evaluate the condition of used or out-of-service equipment are critical to meet the usual tight deadlines of the decision making process.

This article is structured primarily as an attempt to assist the organizations in charge of evaluation of used or out-of-service equipment to identify and plan the necessary steps in order to determine their suitability for their new intended service. Many of the issues discussed here can be also applied to any life extension evaluation program, and therefore throughout this report the term out-of-service is interchangeable with ‘used’ equipment. The focus of this article is mainly static equipment as re-using of machinery or rotating equipment would require a rather different approach [1].

Two case studies included at the end of this report demonstrate the benefits of adopting a systematic approach in evaluating used equipment.
Inner Detection of Corrosion by Ultrasonic Phased Array in Underground Compressed Natural Gas Storage Well
Authors: Miao Cunjian , Guo Weican , Ling Zhangwei , Tang Ping
Published: December 2016

Compressed natural gas (CNG) storage well is a kind of pressure vessel buried underground. The detection of corrosion, which may be induced by the surrounding soil and different medium, is important for the safety security of the well, and protects it from CNG leakage or casing explosion. Among non-destructive examination techniques for corrosion detecting, the ultrasonic techniques are popularly utilized, in which the phased array approach can offer distinct advantages. To investigate both reliability and applicability of the phased array technique in the storage well, a complex design with a 512-element ultrasonic phased array that covered the entire cross-section was discussed, and phased array parameters were determined, including array elements, array element size, ultrasonic frequency and so on. An ultrasonic testing system was designed based on the above design, including a frame for holding phased array probes, a specific vessel for storing ultrasonic cards and other components, and an in-pipe robot designed for instruments’ moving in the storage well. The general corrosion condition described by thickness images were captured by the ultrasonic testing system with B, C and D-scan functions, in which circumferential electronic linear scanning was performed by the phased array probes and axial scanning was done by a mechanical scanning device. A method for minimizing the external pressure from water column necessary for coupling was put forward in the scanning and detection process. The sample for CNG storage well with artificial defects was built in laboratory environments and experiments were conducted to validate detection effects, and the phased array technique provided good sensitivity and efficiency, which may lead to a successful application in CNG storage well examination.
Evolving Design Methods for Modern High Temperature Power Plant Components
Authors: Perrin Ian , Parker Jonathan
Published: December 2016

This paper summarizes recommendations made as part of the work considering modernization of ASME Section I (Power Boilers). It is not intended to provide a comprehensive review of issues regarding design guidelines for components. However, to introduce the context of the approaches that are recommended, background is provided on a number of topics related to Design-By-Analysis, Design-By-Formula, Design-For-Safety and Design-For-Lifetime. Benefits, shortcomings or inconsistencies associated with particular approaches are discussed. It is apparent that no one current Code or Standard has a method that can be universally adopted. This paper outlines the features of a Design-By-Analysis approach that is both relevant, technically consistent and which considers the key modes of structural behavior and material response.
Calculation Methods for Thick Walled Components Under Creep Fatigue: Review and Advanced Concepts
Authors: Oesterlin Heiner , Maier Gerhard
Published: December 2016

A full scale creep-fatigue test component made of P91 was developed and tested as part of the MACPLUS (European Union FP7) project. Current international standards for lifetime assessment for thick walled power plant components were applied. In addition an advanced concept based on creep-fatigue crack growth was also used in finite element simulations. The results are compared with each other and the measurements of the heavily instrumented component. Individual strength and weaknesses as well as general challenges for creep-fatigue lifetime assessment are analyzed and discussed.
Closed-Form Relations for Stress Intensity Factor Influence Coefficients for Axial Outside Surface Flaws in Cylinders for Appendix A of ASME Section XI
Authors: Xu Steven X. , Lee Darrell R. , Scarth Douglas A. , Cipolla Russell C.
Published: December 2016

Linear elastic fracture mechanics based flaw evaluation procedures in Section XI of the ASME Boiler and Pressure Vessel Code require calculation of the stress intensity factor. Article A-3000 of Appendix A in ASME Section XI prescribes a method to calculate the stress intensity factor for a surface or subsurface flaw by making use of the flaw location stress distribution obtained in the absence of the flaw. The 2015 Edition of ASME Section XI implemented a number of significant improvements in Article A-3000, including closed-form equations for calculating stress intensity factor influence coefficients for circumferential flaws on the inside surface of cylinders. Closed-form equations for stress intensity factor influence coefficients for axial flaws on the inside surface of cylinders have also been developed. Ongoing improvement efforts for Article A-3000 include development of closed-form relations for the stress intensity factor coefficients for flaws on the outside surface of cylinders. The development of closed-form relations for stress intensity factor coefficients for axial flaws on the outside surface of cylinders is described in this paper.
Criteria for Selecting Materials to be Used for Hydrogen Refueling Station Equipment
Authors: Kobayashi Hideo , Yamada Toshihiro , Kobayashi Hiroshi , Matsuoka Saburo
Published: December 2016

In this research paper, the focus is on SUS316 and SUS316L, types of austenitic stainless steel, as materials to be used for hydrogen refueling station (HRS) equipment from which hydrogen will be filled into 70 MPa onboard containers. Data on its characteristics in high-pressure-hydrogen environments, as well as methods of quantitative evaluation, were examined. On the basis of data, criteria for selecting materials and the standards to be used for HRS equipment were established.

The results indicate that the temperature ranges in which SUS316 and SUS316L can be used for HRS equipment with a hydrogen pressure of ≤82 MPa are as follows.

If the actual reduction of area of 75% is ensured, SUS316 and SUS316L can be used in the temperature ranges between −45 and 250 °C for a Ni equivalent of ≥28.5%, between −10 and 250 °C for a Ni equivalent of ≥27.4%, and between 20 and 250 °C for a Ni equivalent of ≥26.3%.
Allowable Piping Imposed Nozzle Loads on Pumps of Large Diameter Nozzles
Authors: Shitolé Bhaskar Dattatray
Published: December 2016

Piping imposed loads are external forces and moments acting on pump suction and discharge nozzles. API 610 2010, 11th Edition, Table 5, provides a basis for nozzle sizes DN 50 to DN 400 for external forces and moments on pump nozzles. There is a frequent need in the industry for pumps of larger volumetric flow rates to have nozzle sizes larger than DN 400. The fast-track requirements of a project schedule needs a realistic and quick methodology for the pump manufacturer and piping stress engineer to have a basis for calculating external forces and moments imposed on nozzle sizes larger than DN 400.

This paper provides a methodology for determining forces and moments on pump nozzle sizes larger than DN 400. The methodology is based on the practical aspect of the most important property of pipe, which influences the quantity of force and moment it can impose.
Creep Life Assessment of High Temperature Advanced Ultrasupercritical (AUSC) Conceptual Boiler Thick-Walled Pressure Components Using Continuum Damage Mechanics Approach
Authors: Ganta B. Reddy , Soare Monica , Shen Chen
Published: December 2016

Several nickel-based superalloys have been tested for high temperature applications for use in advanced ultra-supercritical (AUSC) fossil-fired power plants through laboratory and steam loops during the last several years. These materials include Inconel 740H and Haynes 282 which are found to have superior creep strength properties and be appropriate for use in the critical high pressure and high temperature (1400°F) AUSC boiler pressure parts such as superheater outlet header. While these materials have been extensively tested for their creep properties in laboratory test specimens, a real life design application with creep constitutive models is very limited.

In this paper, development of a microstructure sensitive continuum damage mechanics (CDM) creep model for Haynes 282 base material that covers a wide range of stress levels and temperatures suitable for AUSC boiler design applications is described. Various creep mechanisms including diffusion and dislocation phenomena are included. This base material CDM model is then applied for a typical thick-walled high temperature header component and creep life assessment for the design life of the component is estimated. This analysis along with weldments and their creep properties still under development are considered crucial for identification of high creep damage regions in the component as well as proper design life assessment of the pressure parts.
Microrheology of growing Escherichia coli biofilms investigated by using magnetic force modulation atomic force microscopy
Authors: Gan Tiansheng , Gong Xiangjun , Schönherr Holger , Zhang Guangzhao
Published: December 2016

Microrheology of growing biofilms provides insightful information about its structural evolution and properties. In this study, the authors have investigated the microrheology of Escherichia coli (strain HCB1) biofilms at different indentation depth (δ) by using magnetic force modulation atomic force microscopy as a function of disturbing frequency (f). As δ increases, the dynamic stiffness (ks) for the biofilms in the early stage significantly increases. However, it levels off when the biofilms are matured. The facts indicate that the biofilms change from inhomogeneous to homogeneous in structure. Moreover, ks is scaled to f, which coincides with the rheology of soft glasses. The exponent increases with the incubation time, indicating the fluidization of biofilms. In contrast, the upper layer of the matured biofilms is solidlike in that the storage modulus is always larger than the loss modulus, and its viscoelasticity is slightly influenced by the shear stress.
Acoustic-assisted assembly of an individual monochromatic ultralong carbon nanotube for high on-current transistors
Authors: Zhu Zhenxing , Wei Nan , Xie Huanhuan , Zhang Rufan , Bai Yunxiang , Wang Qi , Zhang Chenxi , Wang Sheng , Peng Lianmao , Dai Liming , Wei Fei
Published: December 2016

Consistent-chirality carbon nanotube tangles with high on-currents in transistors.
Ultra-smooth glassy graphene thin films for flexible transparent circuits
Authors: Dai Xiao , Wu Jiang , Qian Zhicheng , Wang Haiyan , Jian Jie , Cao Yingjie , Rummeli Mark H. , Yi Qinghua , Liu Huiyun , Zou Guifu
Published: December 2016

A type of glassy graphene thin film was studied and applied for laser direct writing circuits.
One year later, Zika scientists prepare for a long war
Authors: Vogel Gretchen
Published: December 2016

Researchers still don't understand the risks, but worry about a possible second wave of birth defects.
The future of bionic dynamos
Authors: Dagdeviren Canan
Published: December 2016

Internal organs have the potential to power implantable devices
Ralph J. Cicerone (1943–2016)
Authors: Holdren John P. , McNutt Marcia K.
Published: December 2016

A leader in science and policy championed efforts to understand and tackle climate change
Chronic Rhinosinusitis and the Evolving Understanding of Microbial Ecology in Chronic Inflammatory Mucosal Disease
Authors: Hoggard Michael , Wagner Mackenzie Brett , Jain Ravi , Taylor Michael W. , Biswas Kristi , Douglas Richard G.
Published: December 2016

Chronic rhinosinusitis (CRS) encompasses a heterogeneous group of debilitating chronic inflammatory sinonasal diseases. Despite considerable research, the etiology of CRS remains poorly understood, and debate on potential roles of microbial communities is unresolved. Modern culture-independent (molecular) techniques have vastly improved our understanding of the microbiology of the human body. Recent studies that better capture the full complexity of the microbial communities associated with CRS reintroduce the possible importance of the microbiota either as a direct driver of disease or as being potentially involved in its exacerbation. This review presents a comprehensive discussion of the current understanding of bacterial, fungal, and viral associations with CRS, with a specific focus on the transition to the new perspective offered in recent years by modern technology in microbiological research. Clinical implications of this new perspective, including the role of antimicrobials, are discussed in depth. While principally framed within the context of CRS, this discussion also provides an analogue for reframing our understanding of many similarly complex and poorly understood chronic inflammatory diseases for which roles of microbes have been suggested but specific mechanisms of disease remain unclear. Finally, further technological advancements on the horizon, and current pressing questions for CRS microbiological research, are considered.
Whole-Genome Sequencing of Mycobacterium tuberculosis Provides Insight into the Evolution and Genetic Composition of Drug-Resistant Tuberculosis in Belarus
Authors: Wollenberg Kurt R. , Desjardins Christopher A. , Zalutskaya Aksana , Slodovnikova Vervara , Oler Andrew J. , Quiñones Mariam , Abeel Thomas , Chapman Sinead B. , Tartakovsky Michael , Gabrielian Andrei , Hoffner Sven , Skrahin Aliaksandr , Birren Bruce W. , Rosenthal Alexander , Skrahina Alena , Earl Ashlee M.
Published: December 2016

The emergence and spread of drug-resistant
Mycobacterium tuberculosis
(DR-TB) are critical global health issues. Eastern Europe has some of the highest incidences of DR-TB, particularly multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. To better understand the genetic composition and evolution of MDR- and XDR-TB in the region, we sequenced and analyzed the genomes of 138
M. tuberculosis
isolates from 97 patients sampled between 2010 and 2013 in Minsk, Belarus. MDR and XDR-TB isolates were significantly more likely to belong to the Beijing lineage than to the Euro-American lineage, and known resistance-conferring loci accounted for the majority of phenotypic resistance to first- and second-line drugs in MDR and XDR-TB. Using a phylogenomic approach, we estimated that the majority of MDR-TB was due to the recent transmission of already-resistant
M. tuberculosis
strains rather than repeated
de novo
evolution of resistance within patients, while XDR-TB was acquired through both routes. Longitudinal sampling of
M. tuberculosis
from 34 patients with treatment failure showed that most strains persisted genetically unchanged during treatment or acquired resistance to fluoroquinolones. HIV+ patients were significantly more likely to have multiple infections over time than HIV− patients, highlighting a specific need for careful infection control in these patients. These data provide a better understanding of the genomic composition, transmission, and evolution of MDR- and XDR-TB in Belarus and will enable improved diagnostics, treatment protocols, and prognostic decision-making.
A Fungus-Specific Protein Domain Is Essential for RasA-Mediated Morphogenetic Signaling in Aspergillus fumigatus
Authors: Al Abdallah Qusai , Norton Tiffany S. , Hill Amy M. , LeClaire Lawrence L. , Fortwendel Jarrod R.
Published: December 2016

Aspergillus fumigatus
is an important fungal pathogen against which limited treatments exist. During invasive disease,
A. fumigatus
hyphae grow in a highly polarized fashion, forming filaments that invade blood vessels and disseminate to distant sites. Once invasion and dissemination occur, mortality rates are high. We have previously shown that the Ras signaling pathway is an important regulator of the hyphal growth machinery supporting virulence in
A. fumigatus
. Here, we show that functional Ras signaling in
A. fumigatus
requires a novel, fungus-specific domain within the Ras protein. This domain is highly conserved among fungi, yet absent in higher eukaryotes, suggesting a potentially crucial difference in the regulation of Ras pathway activity between the human host and the fungal pathogen. Exploration of the mechanisms through which this domain regulates signaling could lead to novel antifungal therapies specifically targeting fungal Ras pathways.
Global Role of Cyclic AMP Signaling in pH-Dependent Responses in Candida albicans
Authors: Hollomon Jeffrey M. , Grahl Nora , Willger Sven D. , Koeppen Katja , Hogan Deborah A.
Published: December 2016

Candida albicans
is a human commensal and the causative agent of candidiasis, a potentially invasive and life-threatening infection.
C. albicans
experiences wide changes in pH during both benign commensalism (a common condition) and pathogenesis, and its morphology changes in response to this stimulus. Neutral pH is considered an activator of hyphal growth through Rim101, but the effect of low pH on other morphology-related pathways has not been extensively studied. We sought to determine the role of cyclic AMP signaling, a central regulator of morphology, in the sensing of pH. In addition, we asked broadly what cellular processes were altered by pH in both the presence and absence of this important signal integration system. We concluded that cAMP signaling is impacted by pH and that cAMP broadly impacts
C. albicans
physiology in both pH-dependent and -independent ways.
Randomised controlled trial of alternative messages to increase enrolment in a healthy food programme among individuals with diabetes
Authors: Gopalan A , Paramanund J , Shaw P A , Patel D , Friedman J , Brophy C , Buttenheim A M , Troxel A B , Asch D A , Volpp K G
Published: December 2016

Objectives

We compared the effectiveness of diabetes-focused messaging strategies at increasing enrolment in a healthy food programme among adults with diabetes.

Methods

Vitality is a multifaceted wellness benefit available to members of Discovery Health, a South Africa-based health insurer. One of the largest Vitality programmes is HealthyFood (HF), an incentive-based programme designed to encourage healthier diets by providing up to 25% cashback on healthy food purchases. We randomised adults with type 2 diabetes to 1 of 5 arms: (1) control, (2) a diabetes-specific message, (3) a message with a recommendation of HF written from the perspective of a HF member with diabetes, (4) a message containing a physician's recommendation of HF, or (5) the diabetes-specific message from arm 2 paired with an ‘enhanced active choice’(EAC). In an EAC, readers are asked to make an immediate choice (in this case, to enrol or not enrol); the pros and cons associated with the preferred and non-preferred options are highlighted. HF enrolment was assessed 1 month following the first emailed message.

Results

We randomised 3906 members. After excluding those who enrolled in HF or departed from the Vitality programme before the first intervention email, 3665 (94%) were included in a modified intent-to-treat analysis. All 4 experimental arms had significantly higher HF enrolment rates compared with control (p<0.0001 for all comparisons). When comparing experimental arms, the diabetes-specific message with the EAC had a significantly higher enrolment rate (12.6%) than the diabetes-specific message alone (7.6%, p=0.0016).

Conclusions

Messages focused on diabetes were effective at increasing enrolment in a healthy food programme. The addition of a framed active choice to a message significantly raised enrolment rates in this population. These findings suggest that simple, low-cost interventions can enhance enrolment in health promoting programmes and also be pragmatically tested within those programmes.

Trial registration number

NCT02462057.
Validity of self-reported myocardial infarction and stroke in regions with Sami and Norwegian populations: the SAMINOR 1 Survey and the CVDNOR project
Authors: Eliassen Bent-Martin , Melhus Marita , Tell Grethe S , Borch Kristin Benjaminsen , Braaten Tonje , Broderstad Ann Ragnhild , Graff-Iversen Sidsel
Published: December 2016

Objective

Updated knowledge on the validity of self-reported myocardial infarction (SMI) and self-reported stroke (SRS) is needed in Norway. Our objective was to compare questionnaire data and hospital discharge data from regions with Sami and Norwegian populations to assess the validity of these outcomes by ethnicity, sex, age and education.

Design

Validation study using cross-sectional questionnaire data and hospital discharge data from all Norwegian somatic hospitals.

Participants and setting

16 865 men and women aged 30 and 36–79 years participated in the Population-based Study on Health and Living Conditions in Sami and Norwegian Populations (SAMINOR) 1 Survey in 2003–2004. Information on SMI and SRS was available from self-administered questionnaires for 15 005 and 15 088 of these participants, respectively. We compared this information with hospital discharge data from 1994 until SAMINOR 1 Survey attendance.

Primary and secondary outcomes

Sensitivity, specificity, positive predictive value (PPV), negative predictive value and κ.

Results

The sensitivity and PPV of SMI were 90.1% and 78.9%, respectively; the PPV increased to 93.1% when all ischaemic heart disease (IHD) diagnoses were included. The SMI prevalence estimate was 2.3% and hospital-based 2.0%. The sensitivity and PPV of SRS were 81.1% and 64.3%, respectively. The SRS prevalence estimate was 1.5% and hospitalisation-based 1.2%. Moderate to no variation was observed in validity according to ethnicity, sex, age and education.

Conclusions

The sensitivity and PPV of SMI were high and moderate, respectively; for SRS, both of these measures were moderate. Our results show that SMI from the SAMINOR 1 Survey may be used in aetiological/analytical studies in this population due to a high IHD-specific PPV. The SAMINOR 1 questionnaire may also be used to estimate the prevalence of acute myocardial infarction and acute stroke.
Improving access and continuity of care for homeless people: how could general practitioners effectively contribute? Results from a mixed study
Authors: Jego Maeva , Grassineau Dominique , Balique Hubert , Loundou Anderson , Sambuc Roland , Daguzan Alexandre , Gentile Gaetan , Gentile Stéphanie
Published: December 2016

Objectives

To analyse the views of general practitioners (GPs) about how they can provide care to homeless people (HP) and to explore which measures could influence their views.

Design

Mixed-methods design (qualitative –> quantitative (cross-sectional observational) → qualitative). Qualitative data were collected through semistructured interviews and through questionnaires with closed questions. Quantitative data were analysed with descriptive statistical analyses on SPPS; a content analysis was applied on qualitative data.

Setting

Primary care; views of urban GPs working in a deprived area in Marseille were explored by questionnaires and/or semistructured interview.

Participants

19 GPs involved in HP's healthcare were recruited for phase 1 (qualitative); for phase 2 (quantitative), 150 GPs who provide routine healthcare (‘standard’ GPs) were randomised, 144 met the inclusion criteria and 105 responded to the questionnaire; for phase 3 (qualitative), data were explored on 14 ‘standard’ GPs.

Results

In the quantitative phase, 79% of the 105 GPs already treated HP. Most of the difficulties they encountered while treating HP concerned social matters (mean level of perceived difficulties=3.95/5, IC 95 (3.74 to 4.17)), lack of medical information (mn=3.78/5, IC 95 (3.55 to 4.01)) patient's compliance (mn=3.67/5, IC 95 (3.45 to 3.89)), loneliness in practice (mn=3.45/5, IC 95 (3.18 to 3.72)) and time required for the doctor (mn=3.25, IC 95 (3 to 3.5)). From qualitative analysis we understood that maintaining a stable follow-up was a major condition for GPs to contribute effectively to the care of HP. Acting on health system organisation, developing a medical and psychosocial approach with closer relation with social workers and enhancing the collaboration between tailored and non-tailored programmes were also other key answers.

Conclusions

If we adapt the conditions of GPs practice, they could contribute to the improvement of HP's health. These results will enable the construction of a new model of primary care organisation aiming to improve access to healthcare for HP.
Beyond hand hygiene: a qualitative study of the everyday work of preventing cross-contamination on hospital wards
Authors: Hor Su-yin , Hooker Claire , Iedema Rick , Wyer Mary , Gilbert Gwendolyn L , Jorm Christine , O'Sullivan Matthew Vincent Neil
Published: December 2016

Background

Hospital-acquired infections are the most common adverse event for inpatients worldwide. Efforts to prevent microbial cross-contamination currently focus on hand hygiene and use of personal protective equipment (PPE), with variable success. Better understanding is needed of infection prevention and control (IPC) in routine clinical practice.

Methods

We report on an interventionist video-reflexive ethnography study that explored how healthcare workers performed IPC in three wards in two hospitals in New South Wales, Australia: an intensive care unit and two general surgical wards. We conducted 46 semistructured interviews, 24 weeks of fieldwork (observation and videoing) and 22 reflexive sessions with a total of 177 participants (medical, nursing, allied health, clerical and cleaning staff, and medical and nursing students). We performed a postintervention analysis, using a modified grounded theory approach, to account for the range of IPC practices identified by participants.

Results

We found that healthcare workers' routine IPC work goes beyond hand hygiene and PPE. It also involves, for instance, the distribution of team members during rounds, the choreography of performing aseptic procedures and moving ‘from clean to dirty’ when examining patients. We account for these practices as the logistical work of moving bodies and objects across boundaries, especially from contaminated to clean/vulnerable spaces, while restricting the movement of micro-organisms through cleaning, applying barriers and buffers, and trajectory planning.

Conclusions

Attention to the logistics of moving people and objects around healthcare spaces, especially into vulnerable areas, allows for a more comprehensive approach to IPC through better contextualisation of hand hygiene and PPE protocols, better identification of transmission risks, and the design and promotion of a wider range of preventive strategies and solutions.
Graphene through the looking glass of QFT
Authors: Fialkovsky Ignat V. , Vassilevich Dmitri V.
Published: December 2016

This paper is aimed to review and promote the main applications of the methods of quantum field theory (QFT) to description of quantum effects in graphene. We formulate the effective electromagnetic action following from the Dirac model for the quasi-particles in graphene and apply it for derivation of different observable effects like the induced mean charge, quantized conductivity, Faraday effect and Casimir interaction involving graphene samples.
Quantum AdaBoost algorithm via cluster state
Authors: Li Yuan
Published: December 2016

The principle and theory of quantum computation are investigated by researchers for many years, and further applied to improve the efficiency of classical machine learning algorithms. Based on physical mechanism, a quantum version of AdaBoost (Adaptive Boosting) training algorithm is proposed in this paper, of which purpose is to construct a strong classifier. In the proposed scheme with cluster state in quantum mechanism is to realize the weak learning algorithm, and then update the corresponding weight of examples. As a result, a final classifier can be obtained by combining efficiently weak hypothesis based on measuring cluster state to reweight the distribution of examples.
Improved thermoelectric properties of hole-doped Bi2−xNaxBa2Co2Oy ceramics
Authors: Gao Wenxian , Wang Guangjiang , Li Xinjian , Hu Xing , Song Hongzhang
Published: December 2016

In this work, Bi[Formula: see text]Na[Formula: see text]Ba2Co2O[Formula: see text] ([Formula: see text][Formula: see text]=[Formula: see text]0.00, 0.05, 0.10, 0.15, 0.20, 0.25 and 0.30) ceramic samples were prepared by the conventional solid phase method. The influence of Na element doping on the thermoelectric properties of samples was investigated from 300 K to 950 K. Compared with undoped sample, the Seebeck coefficients of Na-doped samples have only a slight decrease. While, the electrical resistivity of the Na-doped samples reduces, for Bi[Formula: see text]Na[Formula: see text]Ba2Co2O[Formula: see text] ceramic samples with [Formula: see text][Formula: see text][Formula: see text][Formula: see text]0.15, the electrical resistivity decreases with increasing Na doping amounts due to the hole-doping effect. In addition, its temperature-dependent resistivity exhibits metallic electrical conductivity behavior. While, the samples with [Formula: see text][Formula: see text][Formula: see text][Formula: see text]0.20 exhibit semiconductor electrical conductivity behavior at the temperature range of 473–823 K, because of the significant reduction of the electrical resistivity and the slight decrease of Seebeck coefficients, the power factors of the doped samples get a significant improvement. For the most suitable doped sample Bi[Formula: see text]Na[Formula: see text]Ba2Co2O[Formula: see text], its ZT value can reach a better value of 0.2 at 873 K.
New correlation for the temperature-dependent viscosity for saturated liquids
Authors: Tian Jianxiang , Zhang Laibin
Published: December 2016

Based on the recent progress on both the temperature dependence of surface tension [H. L. Yi, J. X. Tian, A. Mulero and I. Cachading, J. Therm. Anal. Calorim. 126 (2016) 1603, and the correlation between surface tension and viscosity of liquids [J. X. Tian and A. Mulero, Ind. Eng. Chem. Res. 53 (2014) 9499], we derived a new multiple parameter correlation to describe the temperature-dependent viscosity of liquids. This correlation is verified by comparing with data from NIST Webbook for 35 saturated liquids including refrigerants, hydrocarbons and others, in a wide temperature range from the triple point temperature to the one very near to the critical temperature. Results show that this correlation predicts the NIST data with high accuracy with absolute average deviation (AAD) less than 1% for 21 liquids and more than 3% for only four liquids, and is clearly better than the popularly used Vogel–Fulcher–Tamman (VFT) correlation.
Influence of photoconductivity on the study of trap levels in polyimide films by photo-stimulated discharge
Authors: He Li-Juan , Yang Xiong , Niu Hui-Qin , Yuan Zhen-Hua , Li Da-Wei , Chen Chun-Tian
Published: December 2016

In this paper, the distribution of the charge trap levels in polyimide (PI) films was investigated by using photo-stimulated discharge (PSD) technique, which was to explore the effect of photoconductivity on photo-stimulated discharge current. The PSD spectra show that the photo-stimulated discharge current of the PI films is mainly distributed in the range of 649–320 nm, but there are two significant current peaks when the wavelength is 300 nm and 244 nm, respectively. By studying the reason of generating two current peaks, it is concluded that the two current peaks are not generated by trapped charge de-trapping but generated by photoconductivity of charge-transfer complex in the PI films. According to the research, it is concluded that the trap levels in PI films are mainly distributed in the range of 1.92 eV–3.88 eV.