bluuebunny/crossref_metadata_2025 huggingface dataset:
Component Test Facility (ComTest) Phase 1 Engineering for 760C (1400F) Advanced Ultra-Supercritical (A-USC) Steam Generator Development
Authors: Weitzel Paul S.
Published: October 2015

Babcock & Wilcox Power Generation Group, Inc. (B&W) has received a competitively bid award from the United States (U.S.) Department of Energy to perform the preliminary front-end engineering design of an advanced ultra-supercritical (A-USC) steam superheater for a future A-USC component test program (ComTest) achieving 760C (1400F) steam temperature. The current award will provide the engineering data necessary for proceeding to detail engineering, manufacturing, construction and operation of a ComTest. The steam generator superheater would subsequently supply the steam to an A-USC intermediate pressure steam turbine. For this study the ComTest facility site is being considered at the Youngstown Thermal heating plant facility in Youngstown, Ohio.

The ComTest program is important because it would place functioning A-USC components in operation and in coordinated boiler and turbine service. It is also important to introduce the power plant operation and maintenance personnel to the level of skills required and provide initial hands-on training experience. Preliminary fabrication, construction and commissioning plans are to be developed in the study. A follow-on project would eventually provide a means to exercise the complete supply chain events required to practice and refine the process for A-USC power plant design, supply, manufacture, construction, commissioning, operation and maintenance. Representative participants would then be able to transfer knowledge and recommendations to the industry.

ComTest is conceived as firing natural gas in a separate standalone facility that will not jeopardize the host facility or suffer from conflicting requirements in the host plant’s mission that could sacrifice the nickel alloy components and not achieve the testing goals. ComTest will utilize smaller quantities of the expensive materials and reduce the risk in the first operational practice for A-USC technology in the U.S. Components at suitable scale in ComTest provide more assurance before applying them to a full size A-USC demonstration plant. The description of the pre-front-end engineering design study and current results will be presented.
Study on the Parameters Influencing Efficiency of Micro-Gas Turbines: A Review
Authors: Jain Samarth , Roy Soumya , Aggarwal Abhishek , Gupta Dhruv , Kumar Vasu , Kumar Naveen
Published: October 2015

The art and science of gas turbine has traditionally seen a gradual and continuous change over the past few decades. Gas turbines are classified into impulse and reaction types and further into turbojet, turbofan, turboprop, after burning turbojet and micro gas turbine. These turbines find applications in airplanes, large scale industries etc. but these are less suitable for the small scale power generation units due to several factors. Micro gas turbines are set to play a significant role particularly in small-scale power generation using combined heat and power generation among all these types of turbines as the future of power generation lies in decentralised and distributed power generation systems. In the light of making use of the high temperature exhaust of a gas turbine, combined heat and power generation systems are being used to increase the power output and overall efficiency. Micro gas turbines are essentially single-stage, single-shaft and low pressure gas turbines whose capacity ranges from 30–150 KW. In comparison to the conventional turbines, micro gas turbines are compact and have low lubricating oil consumption leading to a simpler lube and sump oil system and because they have fewer rotating parts, this leads to lesser balancing problems. The analysis of micro gas turbines has shown that they are capable of meeting current emission standards of NOx and other pollutants. Even though the installation costs of micro gas turbines are high due to the complexity in adjusting to electrical grid frequency, still these distributed energy systems may prove to be more attractive in a competitive market to those seeking increased reliability as they empower these entities with the capacity of self-generation. The following text reviews the developments in the micro gas turbines with a special focus on the efficiency of its components such as the recuperator, the combustion chamber design and also explores the future prospects of the technology in terms of viability of its application in the automobile sector.
Evaluation for Scalability of a Combined Cycle Using Gas and Bottoming SCO2 Turbines
Authors: Moroz Leonid , Pagur Petr , Rudenko Oleksii , Burlaka Maksym , Joly Clement
Published: October 2015

Bottoming cycles are drawing a real interest in a world where resources are becoming scarcer and the environmental footprint of power plants is becoming more controlled. Reduction of flue gas temperature, power generation boost without burning more fuel and even production of heat for cogeneration applications are very attractive and it becomes necessary to quantify how much can really be extracted from a simple cycle to be converted to a combined configuration.

As supercritical CO2 is becoming an emerging working fluid [2, 3, 5, 7 and 8] due not only to the fact that turbomachines are being designed significantly more compact, but also because of the fluid’s high thermal efficiency in cycles, it raises an increased interest in its various applications. Evaluating the option of combined gas and supercritical CO2 cycles for different gas turbine sizes, gas turbine exhaust gas temperatures and configurations of bottoming cycle type becomes an essential step toward creating guidelines for the question, “how much more can I get with what I have?”.

Using conceptual design tools for the cycle system generates fast and reliable results to draw this type of conclusion. This paper presents both the qualitative and quantitative advantages of combined cycles for scalability using machines ranging from small to several hundred MW gas turbines to determine which configurations of S-CO2 bottoming cycles are best for pure electricity production.
Control of Turbulent Combustion Flow Inside a Gas Turbine Combustion Chamber Using Plasma Actuators
Authors: Ghasemi E. , Soleimanikutanaei Soheil , Lin Cheng-Xian
Published: October 2015

In this paper, effects of a standard plasma actuator on non-premixed turbulent reacting flows in a unique gas turbine combustion chamber have been studied numerically. The computational simulation is conducted by employing the Reynolds Averaged Navier-Stokes (RANS) approach. Chemical reaction kinetics has been modeled using the eddy dissipation concept (EDC) model. The numerical simulation has been carried out by Finite Element Methods. High voltage potential between two copper electrodes separated by a dielectric material has been applied which leads to the generation of plasma and an electric field, which creates a body force. It was found that by orienting the plasma force in the desired direction, combustion rate can be accelerated or controlled. The numerical results have been presented through velocity, temperature, and species concentration profiles under different combustion conditions.
Decision Making for the Collaborative Energy Supply System of Oregon and Washington
Authors: DuPont Bryony , Azam Ridwan , Proper Scott , Cotilla-Sanchez Eduardo , Hoyle Christopher , Piacenza Joseph , Oryshchyn Danylo , Zitney Steve , Bossart Stephen
Published: October 2015

As demand for electricity in the United States continues to increase, it is necessary to explore the means through which the modern power supply system can accommodate both increasing affluence (which is accompanied by increased per-capita consumption) and the continually growing global population. Though there has been a great deal of research into the theoretical optimization of large-scale power systems, research into the use of an existing power system as a foundation for this growth has yet to be fully explored. Current successful and robust power generation systems that have significant renewable energy penetration — despite not having been optimized a priori — can be used to inform the advancement of modern power systems to accommodate the increasing demand for electricity. Leveraging ongoing research projects at Oregon State University and the National Energy Technology Laboratory, this work explores how an accurate and state-of-the-art computational model of the Oregon/Washington (OR/WA) energy system can be employed as part of an overarching power systems optimization scheme that looks to inform the decision making process for next generation power supply systems. Research scenarios that explore an introductory multi-objective power flow analysis for the OR/WA grid will be shown, along with a discussion of future research directions.
Integrating the ASME Performance Test Code 19.1 Approach of Calculating Measurement Uncertainty With the Regression Based Test Methods for Reporting Photovoltaic System Performance
Authors: Lawrence Cecil
Published: October 2015

Solar Photovoltaic (PV) power plants have high performance test measurement uncertainty due to instrument precision limitations and spatial variations associated with irradiance and soiling measurement. Accurate prediction of the measurement uncertainty is critical for both the Owner and the EPC contractor to appropriately manage their risk. While there are several methods for testing the performance of PV plants, regression analysis based methods, like the PVUSA Method and the PPI rating method, are widely used. However, there is limited guidance on uncertainty analysis when using these methods. Most utilities and power producers have familiarity with the ASME PTC 19.1 code for measurement uncertainty analysis and often require the guidelines of PTC 19.1 be followed for evaluating the measurement uncertainty for the performance testing of PV plants. However there is lack of published literature on using the ASME PTC 19.1 approach with regression based PV performance test methods. This paper expands on the limited guidance provided by ASME PTC 19.1 Section 8-6 for regression based analysis and presents a detailed approach of calculating measurement uncertainty for PV power plants when using regression based testing methods. The paper also presents the importance of obtaining a good regression fit to the measurement uncertainty and elaborates on methods to reduce the measurement uncertainty. The overall approach discussed in this paper was applied on performance testing of two large utility-scale PV plants.
Water-Ammonia Cycles for the Utilization of Low Temperature Geothermal Resources
Authors: Fiaschi Daniele , Manfrida Giampaolo , Talluri Lorenzo
Published: October 2015

The research deals with the possibility of effective exploitation of low temperature geothermal energy resources, which are generally much more widespread worldwide compared to conventional high temperature ones, typically available only in limited areas of the Earth. The basic idea is the application of an advanced binary cycle, only thermally coupled to the primary endogen heat source. The selected reference-power cycle is the well-known Kalina, which gives the possibility of optimizing the matching between heat capacities of the geothermal fluid (i.e. typically hot water or saturated steam) and the cycle working fluid, which is a non azeotropic NH3-H2O mixture with variable vaporization temperature at a fixed pressure.

The heat transfer diagrams of the main Kalina heat exchangers, namely the condenser and the evaporator, are analysed with the aim of minimizing the irreversibilities related to the heat transfer. At different fixed NH3-H2O composition and condenser pressures, the evaporator pressure shows an efficiency optimizing value between 40 and 55 bar, generally increasing at higher condenser pressure. At fixed geothermal heat source temperature, condenser/evaporator pressures and working mixture composition, the cycle efficiency increases with increasing evaporator temperature, because of the reduction in the approach temperature difference between the geothermal and the working fluid. Higher efficiencies are found at higher NH3 concentrations.

The proposed Water-Ammonia power cycle is further enhanced introducing a chiller (thus making the power cycle a CCP unit), thanks to the properties of the fluid mixture downstream the absorber, through an intermediate heat exchanger between the condenser and the evaporator.

Mainly due to the better matching of heat capacities between the geothermal and the working fluid, the proposed power cycle offers the possibility of interesting improvements in electrical efficiency compared to traditionally proposed binary cycles using ORCs, at fixed temperature level of the heat source. In the investigated proposal, values of electric efficiency between 15 and 20% are found.

An economic analysis is presented, demonstrating that the CCP system is able to produce electricity at decreased unit cost with respect to the power-only unit.
Developing Green, Highly Efficient Coal-Fired Power Technologies
Authors: Weizhong Feng
Published: October 2015

Optimization and innovation of all systems are needed to increase the energy saving and reduce emissions in coal-fired power plants. Design changes can be made that are inexpensive, low risk and effective.

A series of optimization and innovation designs have been developed to significantly increase the efficiency of 2×1000MW ultra supercritical (USC) units in China. The turbine efficiency limitations due to solid particle erosion are eliminated by these improvements. The normal deterioration of the turbine efficiency has also been eliminated.

The units net efficiency at the rated operation conditions including the Flue Gas Desulphurization (FGD) and Selective Catalytic Reduction (SCR) systems now exceeds 46.5% for a single reheat system.
Concentrated Solar Power Hybrid Gas Turbine Demonstration Test Results
Authors: Teraji David G.
Published: October 2015

One of the most promising renewable energy concepts is the Concentrated Solar Power (CSP) tower with a hybrid combined cycle gas turbine power block. U.S. Department of Energy studies [4] indicate that this type of system can achieve greater than 60% thermal efficiency and result in a lower the levelized cost of electricity (LCOE) as compared to the CSP technology operating today. The air Brayton gas turbine part of the combined cycle system can also operate in a hybrid mode with natural gas resulting in optimizing the plant performance and making it available for fully dispatchable power output even when the solar thermal is not available. Since this concept had not been tested on a MW scale, a CSP tower hybrid gas turbine demonstration plant called Solugas was built near Seville, Spain. A 4.6 MW Mercury™ 50 gas turbine was modified to operate with a high temperature air receiver. The demonstration tests were conducted to ensure the turbine can operate over a broad range of conditions with and without solar energy. The performance and operation safety were critical test objectives. The demonstration test results were excellent and met all program objectives.
Performance Study of a Dimpled-Protruded Air-to-Air Plate Heat Exchanger
Authors: Alqutub Amro M. , Linjawi Majid T. , Alrawi Ismail M.
Published: October 2015

In the present study, the overall heat transfer coefficient, friction factors, and effectiveness of a dimple-protrusion air-to-air counter-flow plate heat exchanger have been measured at low Reynolds number (500 < Re < 4,000). The heat exchanger consists of 4 channels per flow direction built using 1 mm aluminum plates. Dimples are specially arranged such that protrusions are opposed for applications that require structural support to withstand high pressure difference between the two fluids. A maximum heat enhancement level of 3.2 was obtained with a penalty of increased friction factor by 9 times which leads to a maximum performance factor of 1.5. The effectiveness obtained was found to be almost independent of Reynolds number on most tested Re. A detailed uncertainty analysis has been performed to determine the uncertainty in the results.
A Computer Program for Working Fluid Selection of Low Temperature Organic Rankine Cycle
Authors: Ali Muhammad Ansab , Khan Tariq Saeed , Hajri Ebrahim Al , Ayub Zahid H.
Published: October 2015

Fossil fuels are continuously depleting while the global energy demand is growing at a fast rate. Additionally, fossil fuels based power plants contribute to environmental pollution. Search for alternate energy resources and use of industrial waste heat for power production are attractive topics of interest these days. One way of enhancing power production and decreasing the environmental impact is by recuperating and utilizing low grade thermal energy. In recent years, research on use of organic Rankine cycle (ORC) has gained popularity as a promising technology for conversion of heat into useful work or electricity. Due to simple structure of ORC system, it can be easily integrated with any energy source like geothermal energy, solar energy and waste heat. A computer program has been developed in engineering equation solver (EES) environment that analyzes and selects appropriate working fluid for organic Rankine cycle design based on available heat sources. For a given heat source, the program compares energy and exergy performance of various working fluids. The program also includes recuperator performance analysis and compares its effectiveness on the overall thermal performance of the Rankine cycle. This program can assist in preliminary design of ORC with respect to best performing refrigerant fluid selection for the given low temperature heat source.
Sensitivity estimation in time‐of‐flight list‐mode positron emission tomography
Authors: Herraiz J. L. , Sitek A.
Published: October 2015

Purpose:

An accurate quantification of the images in positron emission tomography (PET) requires knowing the actual sensitivity at each voxel, which represents the probability that a positron emitted in that voxel is finally detected as a coincidence of two gamma rays in a pair of detectors in the PET scanner. This sensitivity depends on the characteristics of the acquisition, as it is affected by the attenuation of the annihilation gamma rays in the body, and possible variations of the sensitivity of the scanner detectors. In this work, the authors propose a new approach to handle time‐of‐flight (TOF) list‐mode PET data, which allows performing either or both, a self‐attenuation correction, and self‐normalization correction based on emission data only.

Methods:

The authors derive the theory using a fully Bayesian statistical model of complete data. The authors perform an initial evaluation of algorithms derived from that theory and proposed in this work using numerical 2D list‐mode simulations with different TOF resolutions and total number of detected coincidences. Effects of randoms and scatter are not simulated.

Results:

The authors found that proposed algorithms successfully correct for unknown attenuation and scanner normalization for simulated 2D list‐mode TOF‐PET data.

Conclusions:

A new method is presented that can be used for corrections for attenuation and normalization (sensitivity) using TOF list‐mode data.
Effect of intervening tissues on ultrasonic backscatter measurements of bone: An in vitro study
Authors: Hoffmeister Brent K. , Spinolo P. Luke , Sellers Mark E. , Marshall Peyton L. , Viano Ann M. , Lee Sang-Rok
Published: October 2015

Ultrasonic backscatter techniques are being developed to diagnose osteoporosis. Tissues that lie between the transducer and the ultrasonically interrogated region of bone may produce errors in backscatter measurements. The goal of this study is to investigate the effects of intervening tissues on ultrasonic backscatter measurements of bone. Measurements were performed on 24 cube shaped specimens of human cancellous bone using a 5 MHz transducer. Measurements were repeated after adding a 1 mm thick plate of cortical bone to simulate the bone cortex and a 3 cm thick phantom to simulate soft tissue at the hip. Signals were analyzed to determine three apparent backscatter parameters (apparent integrated backscatter, frequency slope of apparent backscatter, and frequency intercept of apparent backscatter) and three backscatter difference parameters [normalized mean backscatter difference (nMBD), normalized slope of the backscatter difference, and normalized intercept of the backscatter difference]. The apparent backscatter parameters were impacted significantly by the presence of intervening tissues. In contrast, the backscatter difference parameters were not affected by intervening tissues. However, only one backscatter difference parameter, nMBD, demonstrated a strong correlation with bone mineral density. Thus, among the six parameters tested, nMBD may be the best choice for in vivo backscatter measurements of bone when intervening tissues are present.
Triathlon Magazine Canada and the (Re-)Construction of Female Sporting Bodies
Authors: Couture Jesse
Published: October 2015

This paper provides a critical look at the ways in which the female sporting body is discursively constructed within Triathlon Magazine Canada (TMC), Canada’s only triathlon-exclusive magazine. By exploring both visual and narrative representations of the athletic female sporting body, this paper exposes some of the discursive tensions that seem to persist in this popular triathlon-specific text. Both the sport of triathlon and the bodies of triathletes may each be understood as sites where essentialist ideas about the body can be effectively disrupted or challenged but TMC represents a façade of gender progressivism insofar as it (re)produces many of the same heteronormative representations of gender found in other popular sport magazines.
Synthesis, Bioactivity Evaluation, and Toxicity Assessment of Novel Salicylanilide Ester Derivatives as Cercaricides against Schistosoma japonicum and Molluscicides against Oncomelania hupensis
Authors: Wang Weisi , Qin Zhiqiang , Zhu Dan , Wei Yufen , Li Shizhu , Duan Liping
Published: October 2015

A series of novel salicylanilide ester derivatives were synthesized, characterized, and evaluated for cercaricidal potential against
Schistosoma japonicum
and molluscicidal potential against
Oncomelania hupensis
. Four derivatives exhibited remarkable cercaricidal activity superior to that of niclosamide. Among them, the most active compound, 4-chloro-2-((2-methoxy-4-nitrophenyl)carbamoyl)phenyl 4-methoxybenzoate (compound 4c), showed a marked minimum effective cercaricidal concentration as low as 0.43 μM and significant molluscicidal activity, with a 50% lethal concentration (LC
50
) of 0.206 g/m
2
. Particularly, compound 4c displayed 88-fold decreased fish toxicity on
Danio rerio
and 44-fold reduced cytotoxicity on human kidney HEK293 cells in comparison with the toxicity of niclosamide. The results indicated that 4c could serve as a promising drug candidate, with environmental safety properties, against
Schistosoma japonicum
at transmission stages. The preliminary molecular mechanism of target compounds in
Schistosoma japonicum
cercariae was also investigated. Salicylanilide ester derivatives exhibited an inhibitory effect on nitric oxide synthase (NOS) but no effect on lactate dehydrogenase (LDH) and acetylcholinesterase (AChE), and a strong and significant correlation between NOS inhibitory efficacy and cercaricidal activity was observed. In addition, 4c could downregulate the expression of NOS in a dose-dependent manner. These results suggested that NOS was probably one of the drug targets of salicylanilide esters.
Cadazolid Does Not Promote Intestinal Colonization of Vancomycin-Resistant Enterococci in Mice
Authors: Seiler Peter , Enderlin-Paput Michel , Pfaff Philippe , Weiss Maria , Ritz Daniel , Clozel Martine , Locher Hans H.
Published: October 2015

The promotion of colonization with vancomycin-resistant enterococci (VRE) is one potential side effect during treatment of
Clostridium difficile
-associated diarrhea (CDAD), resulting from disturbances in gut microbiota. Cadazolid (CDZ) is an investigational antibiotic with potent
in vitro
activity against
C. difficile
and against VRE and is currently in clinical development for the treatment of CDAD. We report that CDZ treatment did not lead to intestinal VRE overgrowth in mice.
Activity of Tobramycin against Cystic Fibrosis Isolates of Burkholderia cepacia Complex Grown as Biofilms
Authors: Kennedy Sarah , Beaudoin Trevor , Yau Yvonne C. W. , Caraher Emma , Zlosnik James E. A. , Speert David P. , LiPuma John J. , Tullis Elizabeth , Waters Valerie
Published: October 2015

Pulmonary infection with
Burkholderia cepacia
complex in cystic fibrosis (CF) patients is associated with more-rapid lung function decline and earlier death than in CF patients without this infection. In this study, we used confocal microscopy to visualize the effects of various concentrations of tobramycin, achievable with systemic and aerosolized drug administration, on mature
B. cepacia
complex biofilms, both in the presence and absence of CF sputum. After 24 h of growth, biofilm thickness was significantly reduced by exposure to 2,000 μg/ml of tobramycin for
Burkholderia cepacia
,
Burkholderia multivorans
, and
Burkholderia vietnamiensis
; 200 μg/ml of tobramycin was sufficient to reduce the thickness of
Burkholderia dolosa
biofilm. With a more mature 48-h biofilm, significant reductions in thickness were seen with tobramycin at concentrations of ≥100 μg/ml for all
Burkholderia
species. In addition, an increased ratio of dead to live cells was observed in comparison to control with tobramycin concentrations of ≥200 μg/ml for
B. cepacia
and
B. dolosa
(24 h) and ≥100 μg/ml for
Burkholderia cenocepacia
and
B. dolosa
(48 h). Although sputum significantly increased biofilm thickness, tobramycin concentrations of 1,000 μg/ml were still able to significantly reduce biofilm thickness of all
B. cepacia
complex species with the exception of
B. vietnamiensis
. In the presence of sputum, 1,000 μg/ml of tobramycin significantly increased the dead-to-live ratio only for
B. multivorans
compared to control. In summary, although killing is attenuated, high-dose tobramycin can effectively decrease the thickness of
B. cepacia
complex biofilms, even in the presence of sputum, suggesting a possible role as a suppressive therapy in CF.
The C-Terminal Zwitterionic Sequence of CotB1 Is Essential for Biosilicification of the Bacillus cereus Spore Coat
Authors: Motomura Kei , Ikeda Takeshi , Matsuyama Satoshi , Abdelhamid Mohamed A. A. , Tanaka Tatsuya , Ishida Takenori , Hirota Ryuichi , Kuroda Akio
Published: October 2015

Silica is deposited in and around the spore coat layer of
Bacillus cereus
, and enhances the spore's acid resistance. Several peptides and proteins, including diatom silaffin and silacidin peptides, are involved in eukaryotic silica biomineralization (biosilicification). Homologous sequence search revealed a silacidin-like sequence in the C-terminal region of CotB1, a spore coat protein of
B. cereus
. The negatively charged silacidin-like sequence is followed by a positively charged arginine-rich sequence of 14 amino acids, which is remarkably similar to the silaffins. These sequences impart a zwitterionic character to the C terminus of CotB1. Interestingly, the
cotB1
gene appears to form a bicistronic operon with its paralog,
cotB2
, the product of which, however, lacks the C-terminal zwitterionic sequence. A Δ
cotB1B2
mutant strain grew as fast and formed spores at the same rate as wild-type bacteria but did not show biosilicification. Complementation analysis showed that CotB1, but neither CotB2 nor C-terminally truncated mutants of CotB1, could restore the biosilicification activity in the Δ
cotB1B2
mutant, suggesting that the C-terminal zwitterionic sequence of CotB1 is essential for the process. We found that the kinetics of CotB1 expression, as well as its localization, correlated well with the time course of biosilicification and the location of the deposited silica. To our knowledge, this is the first report of a protein directly involved in prokaryotic biosilicification.

IMPORTANCE
Biosilicification is the process by which organisms incorporate soluble silicate in the form of insoluble silica. Although the mechanisms underlying eukaryotic biosilicification have been intensively investigated, prokaryotic biosilicification was not studied until recently. We previously demonstrated that biosilicification occurs in
Bacillus cereus
and its close relatives, and that silica is deposited in and around a spore coat layer as a protective coating against acid. The present study reveals that a
B. cereus
spore coat protein, CotB1, which carried a C-terminal zwitterionic sequence, is essential for biosilicification. Our results provide the first insight into mechanisms required for biosilicification in prokaryotes.
Effect of LexA on Chromosomal Integration of CTXϕ in Vibrio cholerae
Authors: Pant Archana , Anbumani D , Bag Satyabrata , Mehta Ojasvi , Kumar Pawan , Saxena Shruti , Nair G. Balakrish , Das Bhabatosh
Published: October 2015

The genesis of toxigenic
Vibrio cholerae
involves acquisition of CTXϕ, a single-stranded DNA (ssDNA) filamentous phage that encodes cholera toxin (CT). The phage exploits host-encoded tyrosine recombinases (XerC and XerD) for chromosomal integration and lysogenic conversion. The replicative genome of CTXϕ produces ssDNA by rolling-circle replication, which may be used either for virion production or for integration into host chromosome. Fine-tuning of different ssDNA binding protein (Ssb) levels in the host cell is crucial for cellular functioning and important for CTXϕ integration. In this study, we mutated the master regulator gene of SOS induction,
lexA
, of
V. cholerae
because of its known role in controlling levels of Ssb proteins in other bacteria. CTXϕ integration decreased in cells with a Δ
lexA
mutation and increased in cells with an SOS-noninducing mutation,
lexA
(Ind
−
). We also observed that overexpression of host-encoded Ssb (VC0397) decreased integration of CTXϕ. We propose that LexA helps CTXϕ integration, possibly by fine-tuning levels of host- and phage-encoded Ssbs.

IMPORTANCE
Cholera toxin is the principal virulence factor responsible for the acute diarrheal disease cholera. CT is encoded in the genome of a lysogenic filamentous phage, CTXϕ.
Vibrio cholerae
has a bipartite genome and harbors single or multiple copies of CTXϕ prophage in one or both chromosomes. Two host-encoded tyrosine recombinases (XerC and XerD) recognize the folded ssDNA genome of CTXϕ and catalyze its integration at the dimer resolution site of either one or both chromosomes. Fine-tuning of ssDNA binding proteins in host cells is crucial for CTXϕ integration. We engineered the
V. cholerae
genome and created several reporter strains carrying Δ
lexA
or
lexA
(Ind
−
) alleles. Using the reporter strains, the importance of LexA control of Ssb expression in the integration efficiency of CTXϕ was demonstrated.
How GPs value guidelines applied to patients with multimorbidity: a qualitative study
Authors: Luijks Hilde , Lucassen Peter , van Weel Chris , Loeffen Maartje , Lagro-Janssen Antoine , Schermer Tjard
Published: October 2015

Objectives

To explore and describe the value general practitioner (GPs) attribute to medical guidelines when they are applied to patients with multimorbidity, and to describe which benefits GPs experience from guideline adherence in these patients. Also, we aimed to identify limitations from guideline adherence in patients with multimorbidity, as perceived by GPs, and to describe their empirical solutions to manage these obstacles.

Design

Focus group study with purposive sampling of participants. Focus groups were guided by an experienced moderator who used an interview guide. Interviews were transcribed verbatim. Data analysis was performed by two researchers using the constant comparison analysis technique and field notes were used in the analysis. Data collection proceeded until saturation was reached.

Setting

Primary care, eastern part of The Netherlands.

Participants

Dutch GPs, heterogeneous in age, sex and academic involvement.

Results

25 GPs participated in five focus groups. GPs valued the guidance that guidelines provide, but experienced shortcomings when they were applied to patients with multimorbidity. Taking these patients’ personal circumstances into account was regarded as important, but it was impeded by a consistent focus on guideline adherence. Preventative measures were considered less appropriate in (elderly) patients with multimorbidity. Moreover, the applicability of guidelines in patients with multimorbidity was questioned. GPs’ extensive practical experience with managing multimorbidity resulted in several empirical solutions, for example, using their ‘common sense’ to respond to the perceived shortcomings.

Conclusions

GPs applying guidelines for patients with multimorbidity integrate patient-specific factors in their medical decisions, aiming for patient-centred solutions. Such integration of clinical experience and best evidence is required to practise evidence-based medicine. More flexibility in pay-for-performance systems is needed to facilitate this integration. Several improvements in guideline reporting are necessary to enhance the applicability of guidelines in patients with multimorbidity.
The Malaysian Breast Cancer Survivorship Cohort (MyBCC): a study protocol
Authors: Islam Tania , Bhoo-Pathy Nirmala , Su Tin Tin , Majid Hazreen Abdul , Nahar Azmi Mohd , Ng Chong Guan , Dahlui Maznah , Hussain Samsinah , Cantwell Marie , Murray Liam , Taib Nur Aishah ,   MyBCC study group
Published: October 2015

Introduction

Over recent decades, the burden of breast cancer has been increasing at an alarming rate in Asia. Prognostic research findings from Western countries may not readily be adapted to Asia, as the outcome of breast cancer depends on a multitude of factors ranging from genetic, clinical and histological predictors, to lifestyle and social predictors. The primary aim of this study is to determine the impact of lifestyle (eg, nutrition, physical activity), mental and sociocultural condition, on the overall survival and quality of life (QoL) among multiethnic Malaysian women following diagnosis of breast cancer. This study aims to advance the evidence on prognostic factors of breast cancer within the Asian setting. The findings may guide management of patients with breast cancer not only during active treatment but also during the survivorship period.

Methods

This hospital-based prospective cohort study will comprise patients with breast cancer (18 years and above), managed in the University Malaya Medical Centre (UMMC). We aim to recruit 1000 cancer survivors over a 6-year period. Data collection will occur at baseline (within 3 months of diagnosis), 6 months, and 1, 3 and 5 years following diagnosis. The primary outcomes are disease-free survival and overall survival, and secondary outcome is QoL. Factors measured are demographic and socioeconomic factors, lifestyle factors (eg, dietary intake, physical activity), anthropometry measurements (eg, height, weight, waist, hip circumference, body fat analysis), psychosocial aspects, and complementary and alternative medicine (CAM) usage.

Ethics and dissemination

This protocol was approved by the UMMC Ethical Committee in January 2012. All participants are required to provide written informed consent. The findings from our cohort study will be disseminated via scientific publication as well as presentation to stakeholders including the patients, clinicians, the public and policymakers, via appropriate avenues.
Comparative safety and effectiveness of long-acting inhaled agents for treating chronic obstructive pulmonary disease: a systematic review and network meta-analysis
Authors: Tricco Andrea C , Strifler Lisa , Veroniki Areti-Angeliki , Yazdi Fatemeh , Khan Paul A , Scott Alistair , Ng Carmen , Antony Jesmin , Mrklas Kelly , D'Souza Jennifer , Cardoso Roberta , Straus Sharon E
Published: October 2015

Objective

To compare the safety and effectiveness of long-acting β-antagonists (LABA), long-acting antimuscarinic agents (LAMA) and inhaled corticosteroids (ICS) for managing chronic obstructive pulmonary disease (COPD).

Setting

Systematic review and network meta-analysis (NMA).

Participants

208 randomised clinical trials (RCTs) including 134 692 adults with COPD.

Interventions

LABA, LAMA and/or ICS, alone or in combination, versus each other or placebo.

Primary and secondary outcomes

The proportion of patients with moderate-to-severe exacerbations. The number of patients experiencing mortality, pneumonia, serious arrhythmia and cardiovascular-related mortality (CVM) were secondary outcomes.

Results

NMA was conducted including 20 RCTs for moderate-to-severe exacerbations for 26 141 patients with an exacerbation in the past year. 32 treatments were effective versus placebo including: tiotropium, budesonide/formoterol, salmeterol, indacaterol, fluticasone/salmeterol, indacaterol/glycopyrronium, tiotropium/fluticasone/salmeterol and tiotropium/budesonide/formoterol. Tiotropium/budesonide/formoterol was most effective (99.2% probability of being the most effective according to the Surface Under the Cumulative RAnking (SUCRA) curve). NMA was conducted on mortality (88 RCTs, 97 526 patients); fluticasone/salmeterol was more effective in reducing mortality than placebo, formoterol and fluticasone alone, and was the most effective (SUCRA=71%). NMA was conducted on CVM (37 RCTs, 55 156 patients) and the following were safest: salmeterol versus each OF placebo, tiotropium and tiotropium (Soft Mist Inhaler (SMR)); fluticasone versus tiotropium (SMR); and salmeterol/fluticasone versus tiotropium and tiotropium (SMR). Triamcinolone acetonide was the most harmful (SUCRA=81%). NMA was conducted on pneumonia occurrence (54 RCTs, 61 551 patients). 24 treatments were more harmful, including 2 that increased risk of pneumonia versus placebo; fluticasone and fluticasone/salmeterol. The most harmful agent was fluticasone/salmeterol (SUCRA=89%). NMA was conducted for arrhythmia; no statistically significant differences between agents were identified.

Conclusions

Many inhaled agents are available for COPD, some are safer and more effective than others. Our results can be used by patients and physicians to tailor administration of these agents.

Protocol registration number

PROSPERO # CRD42013006725.
Resilience as a correlate of acute stress disorder symptoms in patients with acute myocardial infarction
Authors: Meister Rebecca E , Weber Tania , Princip Mary , Schnyder Ulrich , Barth Jürgen , Znoj Hansjörg , Schmid Jean-Paul , von Känel Roland
Published: October 2015

Objectives

Myocardial infarction (MI) may be experienced as a traumatic event causing acute stress disorder (ASD). This mental disorder has an impact on the daily life of patients and is associated with the development of post-traumatic stress disorder. Trait resilience has been shown to be a protective factor for post-traumatic stress disorder, but its association with ASD in patients with MI is elusive and was examined in this study.

Methods

We investigated 71 consecutive patients with acute MI within 48 h of having stable haemodynamic conditions established and for 3 months thereafter. All patients completed the Acute Stress Disorder Scale and the Resilience Scale to self-rate the severity of ASD symptoms and trait resilience, respectively.

Results

Hierarchical regression analysis showed that greater resilience was associated with lower symptoms of ASD independent of covariates (b=−0.22, p<0.05). Post hoc analysis revealed resilience level to be inversely associated with the ASD symptom clusters of re-experiencing (b=−0.05, p<0.05) and arousal (b=−0.09, p<0.05), but not with dissociation and avoidance.

Conclusions

The findings suggest that patients with acute MI with higher trait resilience experience relatively fewer symptoms of ASD during MI. Resilience was particularly associated with re-experiencing and arousal symptoms. Our findings contribute to a better understanding of resilience as a potentially important correlate of ASD in the context of traumatic situations such as acute MI. These results emphasise the importance of identifying patients with low resilience in medical settings and to offer them adequate support.
Acute neurological visual loss in young adults: causes, diagnosis and management
Authors: Sawaya R , El Ayoubi N , Hamam R
Published: October 2015

Visual loss in the young adult can be caused by demyelinating diseases, inflammatory and autoimmune processes, infections, ischaemic events, and compressive lesions of the optic nerve. Diagnosis of the aetiologies of visual loss is reached by combining data from radiological studies, electrophysiological tests, and blood and cerebrospinal fluid analysis. Treatment is primarily aimed at decreasing the insult on the optic nerve and eventually controlling the primary disorder. The literature discusses separately the different aetiologies of visual loss. We present a review of the clinical characteristics of visual loss in the young adult, the different diagnostic measures, and the latest therapeutic strategies. The aim of this work is to summarise this entity in a practical way to guide clinicians in the diagnosis and management of this disorder.
Northern cod comeback
Authors: Rose George A. , Rowe Sherrylynn
Published: October 2015

The great “northern” cod (Gadus morhua) stock, formerly among the world’s largest and the icon for depletion and supposed nonrecovery of marine fishes, is making a major comeback after nearly two decades of attrition and fishery moratorium. Using acoustic-trawl surveys of the main prespawning and spawning components of the stock, we show that biomass has increased from tens of thousands of tonnes to >200 thousand tonnes within the last decade. The increase was signalled by massive schooling behaviour in late winter first observed in 2008 in the southern range of the stock (Bonavista Corridor) after an absence for 15 years, perhaps spurred by immigration. Increases in size composition and fish condition and apparent declines in mortality followed, leading to growth rates approaching 30% per annum. In the spring of 2015, large increases in cod abundance and size composition were observed for the first time since the moratorium in the more northerly spawning groups of this stock complex. The cod rebound has paralleled increases in the abundance of capelin (Mallotus villosus), whose abundance declined rapidly in the cold early 1990s but has recently increased during a period of warm ocean temperatures. With continued growth in the capelin stock and frugal management (low fishing mortality), this stock could rebuild, perhaps within less than a decade, to historical levels of sustainable yield. More generally, if this stock can recover, the potential exists for recovery of many other depleted stocks worldwide.
Ergodicity and dynamical localization for Delone–Anderson operators
Authors: Germinet François , Müller Peter , Rojas-Molina Constanza
Published: October 2015

We study the ergodic properties of Delone–Anderson operators, using the framework of randomly colored Delone sets and Delone dynamical systems. In particular, we show the existence of the integrated density of states and, under some assumptions on the geometric complexity of the underlying Delone sets, we obtain information on the almost-sure spectrum of the family of random operators. We then exploit these results to study the Lifshitz-tail behavior of the integrated density of states of a Delone–Anderson operator at the bottom of the spectrum. Furthermore, we use Lifshitz-tail estimates as an input for the multi-scale analysis to prove dynamical localization.
Rigidity of maximal holomorphic representations of Kähler groups
Authors: Spinaci Marco
Published: October 2015

We investigate representations of Kähler groups [Formula: see text] to a semisimple non-compact Hermitian Lie group [Formula: see text] that are deformable to a representation admitting an (anti)-holomorphic equivariant map. Such representations obey a Milnor–Wood inequality similar to those found by Burger–Iozzi and Koziarz–Maubon. Thanks to the study of the case of equality in Royden’s version of the Ahlfors–Schwarz lemma, we can completely describe the case of maximal holomorphic representations. If [Formula: see text], these appear if and only if [Formula: see text] is a ball quotient, and essentially reduce to the diagonal embedding [Formula: see text]. If [Formula: see text] is a Riemann surface, most representations are deformable to a holomorphic one. In that case, we give a complete classification of the maximal holomorphic representations, which thus appear as preferred elements of the respective maximal connected components.
A novel visualization of the geometry of special relativity
Authors: Marr John H.
Published: October 2015

The mathematical treatment and graphical representation of Special Relativity (SR) are well established, yet carry deep implications that remain hard to visualize. This paper presents a new graphical interpretation of the geometry of SR that may, by complementing the standard works, aid the understanding of SR and its fundamental principles in a more intuitive way. From the axiom that the velocity of light remains constant to any inertial observer, the geodesic is presented as a line of constant angle on the complex plane across a set of diverging reference frames. The resultant curve is a logarithmic spiral, and this view of the geodesic is extended to illustrate the relativistic Doppler effect, time dilation, length contraction, the twin paradox, and relativistic radar distance in an original way, whilst retaining the essential mathematical relationships of SR. Using a computer-generated graphical representation of photon trajectories allows a visual comparison between the relativistic relationships and their classical counterparts, to visualize the consequences of SR as velocities become relativistic. The model may readily be extended to other situations, and may be found useful in presenting a fresh understanding of SR through geometric visualization.
Remote Imaging Radar with Ultra-Wideband Chaotic Signals Over Fiber Links
Authors: Xu Hang , Wang Bingjie , Han Hong , Liu Li , Li Jingxia , Wang Yuncai , Wang Anbang
Published: October 2015

We experimentally demonstrate radar remote imaging using a radio technique based on ultra-wideband chaotic signals over fiber links. The radar system includes three parts, i.e. a central station, some optical fiber links and a base station. At the central station, an ultra-wideband chaotic signal is generated from an improved Colpitts oscillator and then is up-converted as a probe signal. The probe signal is then converted to be in optical domain by the external modulation technique on laser diode for transmitting over a fiber link to a remote base station. At the base station, the probe signal is converted to be in electrical domain and then launched by a microwave antenna. After being received by another antenna, the echo signal from a target is converted to be in optical domain and then transmitted over a fiber link back to the central station. By optical-to-electrical conversion and down conversion, the echo chaotic signal is recovered. Utilizing the correlation method and back projection algorithm, an image of the target in the two-dimensional space can be realized at the central station. Our experiments successfully performed remote imaging for both planar and spherical reflectors with a distance over 10 km. The down-range resolution of 6-cm and 8-cm cross-range resolution were obtained, respectively. We will show that the power spectrum of the probe signal is adjustable in the spectral mask according to the Federal Communications Commission standards, therefore can avoid interference to the existing narrowband radio signals.