bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling of Particle Transport, Erosion and Deposition in Power Plant Gas Paths
Authors: Borello Domenico , Cardillo Lucio , Corsini Alessandro , Delibra Giovanni , Rispoli Franco , Salvagni Alessandro , Sheard A. G. , Venturini Paolo
Published: September 2016

Flow evolving in turbomachinery applications is turbulent and laden with particles, such as dust, ash, dirt, etc. This would affect the behaviour of the turbine components given that solid particles can impact and then bounce off, deposit or erode their surfaces. Erosion and deposition phenomena may seriously affect the components performance, because they alter the blade profile and hence the flow field. It is thus clear that the prediction of these phenomena would be of great help form both design optimization and maintenance of turbomachinery. Besides experiments, in the last decade CFD became one of the main tool for studying flow evolution within turbine components, phenomena that involve them, and prediction of problems. In particle-laden flows, CFD is used to simulate the flow field, but also solid particle transport and dispersion, impact mechanics, adhesion or rebound, and erosion. Several approaches can be used depending on the kind of application studied and information expected. Particle transport can be simulated adopting a single or cluster of particle tracking approach (Crowe et al, 2006). Since to have a statistically independent results a large number of simulated particles is needed, the for-mer approach can be used when the domain size is not too large; moreover the instantaneous flow field is needed, otherwise turbulent dispersion of particles has to be accounted for. The cluster of particles approach (i.e., Particle Cloud Tracking model, Baxter 1989) overcomes some of these problems, since it usually uses a model for particle dispersion, computing very few trajectories to simulate a large number of particles. Particle impact/rebound and deposit/erosion are modelled using one of the available choice. For instance, impact mechanics can be modelled according to the Johnson-Kendall-Roberts theory (1971) if the particle temperature is not large enough to modify the physical properties of the particles, or the Thornton and Ning variation (1997). When the effect of temperature becomes relevant, a temperature based sticking model is used, such as that of Walsh et al. (1990). Erosion can be studied according to the model of Tabackof (1979). Aim of this study is showing how CFD can be used to simulate particle deposition/erosion in all the components of a turbine (i.e. fan, turbine, compressor), and predict the most critical regions of a given component. This will be done introducing the numerical models used for some applications, describing reference test cases, and showing/discussing results.
Modelling the Microslip in the Flange Joint and its Effect on the Dynamics of a Multi-Stage Bladed Disk Assembly
Authors: Firrone Christian M. , Battiato Giuseppe , Epureanu Bogdan I.
Published: September 2016

The complex architecture of aircraft engines requires demanding computational efforts to take into account the dynamic coupling of the many components constituting the whole assembly. For this reason numerically efficient Reduced Order Models (ROM) and techniques have been developed with the aim of reproducing the global dynamics of the system being computationally fast at the same time. In particular, ROMs have been presented to perform the modal analysis and the calculation of the forced response of rotating components like turbine bladed disks multi-stage assembly. In order to study the effect that joints may have in terms of nonlinearities due to friction in complex structures, in this paper the flange joint is studied as a source of damping due to microslip occurring at the contact interface between two turbine disks. An analytical contact model is proposed to calculate the local microslip based on the different deformations that the two flanges take during vibration. The model is first introduced using a simple geometry representing two flanges in contact and then it is applied to a reduced FE model in order to calculate the nonlinear forced response.
Optimal Automated Fracture Risk Assessment of 3D Gas Turbine Engine Components
Authors: Enright Michael P. , Moody Jonathan P. , Sobotka James C.
Published: September 2016

High-energy rotating components of gas turbine engines may contain rare material anomalies that can lead to uncontained engine failures. A zone-based risk assessment approach can be used to estimate component fracture risk based on groupings of finite elements (FEs) called zones. Creating zones manually is time consuming and requires human judgment. Algorithms have been developed to automatically create zones based on individual FEs, but the associated computation times increase exponentially with the number of FEs. 3D FE models typically contain millions of finite elements. Computation of component risk using individual FE-based automated zoning algorithms may take days or even weeks to complete. An improved optimal autozoning methodology has been developed that substantially reduces the computation time associated with fracture risk assessments. It combines finite elements with similar properties (i.e., stress, temperature, proximity to the surface) into groups called “pre-zones”. An automated zone creation algorithm is applied to pre-zones rather than individual FEs, reducing the overall number of computations. In this paper, the optimal autozoning methodology is presented and illustrated for FE geometries in both 2D and 3D gas turbine engine components. Based on the demonstration problem results, it is shown that the computation speed associated with the optimal autozoning algorithm is expected to be three to four orders of magnitude faster than a previous algorithm that created zones at individual FEs. The pre-zoning-based algorithm also requires less memory than previous algorithms, enabling it to solve much larger models. The resulting algorithm provides a feasible and realistic solution for fracture risk assessment of 2D and 3D component finite element models.
Rotating Machinery Monitoring and Fault Diagnosis With Neural Network Enhanced Fuzzy Logic Expert System
Authors: Li Xiaojun , Palazzolo Alan , Wang Zhiyang
Published: September 2016

This paper presents an intelligent monitoring and fault diagnosis approach for rotating machinery by utilizing artificial neural networks and fuzzy logic expert systems (FLES). A recurrent neural network (RNN) is introduced to filter the input signal before they are forwarded to the expert system. The RNN is trained based on existing operational data so that it can adapt to a specific machine’s configurations and conditions. The RNN is able to generate proper baseline signal even if the machine is not under the exact same condition. A fuzzy logical expert system is then used for diagnosis based on the residual signal generated by the RNN. The system is incorporated into an existing comprehensive roto-dynamics software package named LVTRC.
Parametrically Induced Damping in a Cracked Rotor
Authors: Kulesza Zbigniew , Sawicki Jerzy T.
Published: September 2016

The tendency to higher speeds in turbomachinery results in the design of more flexible shafts, which run at speeds above several of their natural frequencies. Due to stress concentration and high spin speed, the rotor dynamic system is more prone to cracks that propagate faster due to low-cycle fatigue loading. The propagating shaft crack usually leads to sudden machine failure, its damage and a serious accident. Therefore, an early shaft crack detection and warning is an important research task.

A transverse shaft crack in a rotor is usually modeled as a local change in the shaft stiffness. It is commonly assumed that this local stiffness change is not constant and varies as a result of a so-called breathing mechanism. This mechanism is explained with periodical opening and closing of crack faces under the load of external forces applied to the rotor. The rotor with a periodically varied stiffness can be modeled as a parametrically excited linear system.

In the presence of a parametric excitation, the vibrations of the system can be amplified or damped at specific excitation frequencies. Usually, the frequencies at which the vibrations are amplified are important, since they can affect stability of the system, and the frequencies at which the vibrations are damped seem to not be of interest. However, the increased damping at specific frequencies is a significant feature of a parametrically excited system that can have some potentially useful applications. The results of earlier studies demonstrate that one of the possible applications of the parametrically-induced damping can be an early detection of a shaft crack.

The unique feature of the increased damping in parametrically excited systems is that this phenomenon can appear only at specific excitation frequencies and at other specific conditions that are not always met. This paper presents the results of a numerical analysis of the influence of Rayleigh’s damping and gyroscopic effects on the increase in damping in a parametrically excited rotor with a cracked shaft. It is shown that the increase in damping in a parametrically excited system is a rare phenomenon that can be observed only at properly selected values of the excitation frequency and Rayleigh’s damping. Furthermore, gyroscopic effects influence the exact values of anti-resonance frequencies at which the phenomenon appears.
Design of Hybrid Hydrostatic/Hydrodynamic Journal Bearings for Optimum Self-Compensation Under Misaligning External Loads
Authors: Martinez Esparza L. F. , Cervantes de Gortari J. G. , Chicurel Uziel E. J.
Published: September 2016

A method to design hybrid hydrostatic/hydrodynamic journal bearings, with the criterion of optimized self-compensation under misaligning loads, is presented. An analysis considering laminar and turbulent flow of a Newtonian incompressible lubricant between the bearing and a misaligned shaft, with restricted lubricant supply to each recess, is discussed. The mathematical model considers the modified steady state Reynolds lubrication equation, an exact function for the local bearing radial clearance with a misaligned shaft, the continuity integral-differential equations at the recess limits and boundary conditions at the cavitation zone and outer limits. The finite-difference method was used, and a modular computer program was developed. The procedure follows a univariate search to determine the optimum size and position of recesses and therefore obtain the design with the maximum reactive moment under misaligning loads. A validation of the model was obtained comparing the results with experimental and calculated data from literature. Results for a 4+4 LBP hybrid bearing design are presented.
Saturated Water Journal Bearings of a Turbo Compressor
Authors: Shoyama Tadayoshi , Kouda Kazuyuki , Ogata Takeshi
Published: September 2016

We have developed a water lubricated journal bearing for water vapor turbo compressor. Utilizing working fluid as liquid lubricant has advantages on high efficiency and structural simplicity of oil-free system. But the evaporation of lubricant effects on various kinds of dynamic properties which must be considered during the development of turbo compressors. The loss, stability, and heat transfer of water lubricated bearings, and the effects of cavitation were studied. When the sub-cool of lubricant water is small, vaporous cavitation is likely to appear. Vaporous cavitation is essentially different from gaseous cavitation of general oil-lubricated bearings in that the evaporation of lubricant occurs which involves latent heat. Because the vaporous cavitation reduces the viscosity loss, and the bearing is cooled not only by sensible heat but also by latent heat, the bearing temperature elevation is suppressed. Another effect of cavitation is stabilization of half speed whirl. We conducted two experiments. Firstly, a sub-scale bearing experiment which consists of 2 conical journal bearings, to investigate the above effects quantitatively and develop a prediction method. Secondly, a full-scale bearing experiment to demonstrate the bearings. As a result, we could drive a 28kg rotor at 31,000rpm stably and efficiently with water lubricated journal bearings.
Do the standard expressions for the electromagnetic field momentum need any modifications?
Authors: Singal Ashok K.
Published: September 2016

We investigate here the question raised in the literature about the correct expression for the electromagnetic field momentum, especially when static or stationary fields are involved. For this, we examine a couple of simple but intriguing cases. First, we consider a system configuration in which electromagnetic field momentum is present even though the system is stationary. We trace the electromagnetic momentum to be present in the form of a continuous transport of electromagnetic energy from one part of the system to another, without causing any net change in the energy of the system. In a second case, we show that the electromagnetic momentum is zero irrespective of whether the charged system is static or in motion, even though the electromagnetic energy is present throughout. We demonstrate that the conventional formulation of electromagnetic field momentum describes the systems consistently without any real contradictions. Here, we also make exposition of a curiosity where electromagnetic energy decreases when the charged system gains velocity. Then we discuss the more general question that has been raised: Are the conventional formulas for energy-momentum of electromagnetic fields valid for all cases? Specifically, in the case of so-called “bound fields,” do we need to change to some modified definitions? We show that in all cases it is only the conventional formulas that lead to results consistent with the rest of physics, including the special theory of relativity, and that any proposed modifications are thus superfluous.
Cytokine-induced memory-like natural killer cells exhibit enhanced responses against myeloid leukemia
Authors: Romee Rizwan , Rosario Maximillian , Berrien-Elliott Melissa M. , Wagner Julia A. , Jewell Brea A. , Schappe Timothy , Leong Jeffrey W. , Abdel-Latif Sara , Schneider Stephanie E. , Willey Sarah , Neal Carly C. , Yu Liyang , Oh Stephen T. , Lee Yi-Shan , Mulder Arend , Claas Frans , Cooper Megan A. , Fehniger Todd A.
Published: September 2016

Cytokine-induced differentiation of memory-like natural killer cells enhances antileukemia responses.
The Effects of Signal Erosion and Core Genome Reduction on the Identification of Diagnostic Markers
Authors: Sahl Jason W. , Vazquez Adam J. , Hall Carina M. , Busch Joseph D. , Tuanyok Apichai , Mayo Mark , Schupp James M. , Lummis Madeline , Pearson Talima , Shippy Kenzie , Colman Rebecca E. , Allender Christopher J. , Theobald Vanessa , Sarovich Derek S. , Price Erin P. , Hutcheson Alex , Korlach Jonas , LiPuma John J. , Ladner Jason , Lovett Sean , Koroleva Galina , Palacios Gustavo , Limmathurotsakul Direk , Wuthiekanun Vanaporn , Wongsuwan Gumphol , Currie Bart J. , Keim Paul , Wagner David M.
Published: September 2016

Whole-genome sequence (WGS) data are commonly used to design diagnostic targets for the identification of bacterial pathogens. To do this effectively, genomics databases must be comprehensive to identify the strict core genome that is specific to the target pathogen. As additional genomes are analyzed, the core genome size is reduced and there is erosion of the target-specific regions due to commonality with related species, potentially resulting in the identification of false positives and/or false negatives.

IMPORTANCE
A comparative analysis of 1,130
Burkholderia
genomes identified unique markers for many named species, including the human pathogens
B. pseudomallei
and
B. mallei
. Due to core genome reduction and signature erosion, only 38 targets specific to
B. pseudomallei
/mallei were identified. By using only public genomes, a larger number of markers were identified, due to undersampling, and this larger number represents the potential for false positives. This analysis has implications for the design of diagnostics for other species where the genomic space of the target and/or closely related species is not well defined.
A Regulatory Circuit Composed of a Transcription Factor, IscR, and a Regulatory RNA, RyhB, Controls Fe-S Cluster Delivery
Authors: Mandin Pierre , Chareyre Sylvia , Barras Frédéric
Published: September 2016

Fe-S clusters are cofactors conserved through all domains of life. Once assembled by dedicated ISC and/or SUF scaffolds, Fe-S clusters are conveyed to their apo-targets via A-type carrier proteins (ATCs).
Escherichia coli
possesses four such ATCs. ErpA is the only ATC essential under aerobiosis. Recent studies reported a possible regulation of the
erpA
mRNA by the small RNA (sRNA) RyhB, which controls the expression of many genes under iron starvation. Surprisingly,
erpA
has not been identified in recent transcriptomic analysis of the iron starvation response, thus bringing into question the actual physiological significance of the putative regulation of
erpA
by RyhB. Using an sRNA library, we show that among 26 sRNAs, only RyhB represses the expression of an
erpA-lacZ
translational fusion. We further demonstrate that this repression occurs during iron starvation. Using mutational analysis, we show that RyhB base pairs to the
erpA
mRNA, inducing its disappearance. In addition, IscR, the master regulator of Fe-S homeostasis, represses expression of
erpA
at the transcriptional level when iron is abundant, but depleting iron from the medium alleviates this repression. The conjunction of transcriptional derepression by IscR and posttranscriptional repression by RyhB under Fe-limiting conditions is best described as an incoherent regulatory circuit. This double regulation allows full expression of
erpA
at iron concentrations for which Fe-S biogenesis switches from the ISC to the SUF system. We further provide evidence that this regulatory circuit coordinates ATC usage to iron availability.

IMPORTANCE
Regulatory small RNAs (sRNAs) have emerged as major actors in the control of gene expression in the last few decades. Relatively little is known about how these regulators interact with classical transcription factors to coordinate genetic responses. We show here how an sRNA, RyhB, and a transcription factor, IscR, regulate expression of an essential gene,
erpA
, in the bacterium
E. coli
. ErpA is involved in the biogenesis of Fe-S clusters, an important class of cofactors involved in a plethora of cellular reactions. Interestingly, we show that RyhB and IscR repress expression of
erpA
under opposite conditions in regard to iron concentration, forming a regulatory circuit called an “incoherent network.” This incoherent network serves to maximize expression of
erpA
at iron concentrations where it is most needed. Altogether, our study paves the way for a better understanding of mixed regulatory networks composed of RNAs and transcription factors.
Cathelicidin Antimicrobial Peptides with Reduced Activation of Toll-Like Receptor Signaling Have Potent Bactericidal Activity against Colistin-Resistant Bacteria
Authors: Kao Cheng , Lin Xiaoyan , Yi Guanghui , Zhang Yunliang , Rowe-Magnus Dean A. , Bush Karen
Published: September 2016

The world is at the precipice of a postantibiotic era in which medical procedures and minor injuries can result in bacterial infections that are no longer effectively treated by antibiotics. Cathelicidins are peptides produced by animals to combat bacterial infections and to regulate innate immune responses. However, cathelicidins are potent activators of the inflammatory response. Cathelicidins with reduced proinflammatory activity and potent bactericidal activity in the low micromolar range against Gram-negative bacteria have been identified. Motifs in cathelicidins that impact bactericidal activity and cytotoxicity to human cells have been elucidated and used to generate peptides that have reduced activation of proinflammatory cytokine production and reduced cytotoxicity to human cells. The resultant peptides have bactericidal activities comparable to that of colistin and can kill colistin-resistant bacteria.

IMPORTANCE
Cathelicidins are antimicrobial peptides that can also increase inflammatory responses. This combination of activities can cause complications in the treatment of bacterial infections despite the pressing need for new antimicrobials. We have identified cathelicidins with decreased activation of inflammatory responses. The peptides kill Gram-negative bacteria at low micromolar concentrations by binding to and perturbing the integrity of the bacterial membrane. The peptides were also engineered to further decrease lysis of human red blood cells. The peptides have activities comparable to those of the polymyxins, a class of antibiotics to which plasmid-borne resistance is rapidly spreading and can kill colistin-resistant bacteria. These peptides are promising candidates for the development of novel antibacterial agents.
Heterogeneity among Isolates Reveals that Fitness in Low Oxygen Correlates with Aspergillus fumigatus Virulence
Authors: Kowalski Caitlin H. , Beattie Sarah R. , Fuller Kevin K. , McGurk Elizabeth A. , Tang Yi-Wei , Hohl Tobias M. , Obar Joshua J. , Cramer Robert A.
Published: September 2016

Previous work has shown that environmental and clinical isolates of
Aspergillus fumigatus
represent a diverse population that occupies a variety of niches, has extensive genetic diversity, and exhibits virulence heterogeneity in a number of animal models of invasive pulmonary aspergillosis (IPA). However, mechanisms explaining differences in virulence among
A. fumigatus
isolates remain enigmatic. Here, we report a significant difference in virulence of two common lab strains, CEA10 and AF293, in the murine triamcinolone immunosuppression model of IPA, in which we previously identified severe low oxygen microenvironments surrounding fungal lesions. Therefore, we hypothesize that the ability to thrive within these lesions of low oxygen promotes virulence of
A. fumigatus
in this model. To test this hypothesis, we performed
in vitro
fitness and
in vivo
virulence analyses in the triamcinolone murine model of IPA with 14 environmental and clinical isolates of
A. fumigatus
. Among these isolates, we observed a strong correlation between fitness in low oxygen
in vitro
and virulence. In further support of our hypothesis, experimental evolution of AF293, a strain that exhibits reduced fitness in low oxygen and reduced virulence in the triamcinolone model of IPA, results in a strain (EVOL20) that has increased hypoxia fitness and a corresponding increase in virulence. Thus, the ability to thrive in low oxygen correlates with virulence of
A. fumigatus
isolates in the context of steroid-mediated murine immunosuppression.

IMPORTANCE
Aspergillus fumigatus
occupies multiple environmental niches, likely contributing to the genotypic and phenotypic heterogeneity among isolates. Despite reports of virulence heterogeneity, pathogenesis studies often utilize a single strain for the identification and characterization of virulence and immunity factors. Here, we describe significant variation between
A. fumigatus
isolates in hypoxia fitness and virulence, highlighting the advantage of including multiple strains in future studies. We also illustrate that hypoxia fitness correlates strongly with increased virulence exclusively in the nonleukopenic murine triamcinolone immunosuppression model of IPA. Through an experimental evolution experiment, we observe that chronic hypoxia exposure results in increased virulence of
A. fumigatus
. We describe here the first observation of a model-specific virulence phenotype correlative with
in vitro
fitness in hypoxia and pave the way for identification of hypoxia-mediated mechanisms of virulence in the fungal pathogen
A. fumigatus.
Emergence of a Potent Multidrug Efflux Pump Variant That Enhances
Campylobacter
Resistance to Multiple Antibiotics
Authors: Yao Hong , Shen Zhangqi , Wang Yang , Deng Fengru , Liu Dejun , Naren Gaowa , Dai Lei , Su Chih-Chia , Wang Bing , Wang Shaolin , Wu Congming , Yu Edward W. , Zhang Qijing , Shen Jianzhong
Published: September 2016

Bacterial antibiotic efflux pumps are key players in antibiotic resistance. Although their role in conferring multidrug resistance is well documented, the emergence of “super” efflux pump variants that enhance bacterial resistance to multiple drugs has not been reported. Here, we describe the emergence of a resistance-enhancing variant (named RE-CmeABC) of the predominant efflux pump CmeABC in
Campylobacter
, a major zoonotic pathogen whose resistance to antibiotics is considered a serious antibiotic resistance threat in the United States. Compared to the previously characterized CmeABC transporters, RE-CmeABC is much more potent in conferring
Campylobacter
resistance to antibiotics, which was shown by increased MICs and reduced intracellular accumulation of antibiotics. Structural modeling suggests that sequence variations in the drug-binding pocket of CmeB possibly contribute to the enhanced efflux function. Additionally, RE-CmeABC expands the mutant selection window of ciprofloxacin, enhances the emergence of antibiotic-resistant mutants, and confers exceedingly high-level resistance to fluoroquinolones, an important class of antibiotics for clinical therapy of campylobacteriosis. Furthermore, RE-CmeABC is horizontally transferable, shifts antibiotic MIC distribution among clinical isolates, and is increasingly prevalent in
Campylobacter jejuni
isolates, suggesting that it confers a fitness advantage under antimicrobial selection. These findings reveal a new mechanism for enhanced multidrug resistance and an effective strategy utilized by bacteria for adaptation to selection from multiple antibiotics.

IMPORTANCE
Bacterial antibiotic efflux pumps are ubiquitously present in bacterial organisms and protect bacteria from the antibacterial effects of antimicrobials and other toxic compounds by extruding them out of cells. Thus, these efflux transporters represent an important mechanism for antibiotic resistance. In this study, we discovered the emergence and increasing prevalence of a unique efflux pump variant that is much more powerful in the efflux of antibiotics and confers multidrug resistance in
Campylobacter
, which is a major foodborne pathogen transmitted to humans via the food chain. Unlike other specific resistance determinants that only allow bacteria to resist a particular antimicrobial, the acquisition of a functionally enhanced efflux pump will empower bacteria with simultaneous resistance to multiple classes of antibiotics. These findings reveal a previously undescribed mechanism for enhanced multidrug resistance and open a new direction for us to understand how bacteria adapt to antibiotic treatment.
Primary tuberculous osteomyelitis of the mandible in a 3-year-old child
Authors: Sambyal Shruti S , Dinkar Ajit D , Jayam Cheranjeevi , Singh Bhanu Pratap
Published: September 2016

A 3-year-old girl child presented with swelling in her right lower jaw that had started 5 days previously. History revealed the child being non-immunised. Initial-evaluation revealed proptosis and bony hard swelling over the right body of the mandible. Radiological evaluation including a CT scan indicated expansile osteolytic lesion involving the body-ramus with onion-peel periosteal reaction suggesting osteomyelitis/malignancy. Blood investigations showed raised erythrocyte sedimentation rate and eosinophilia. Family screening for tuberculosis (TB) revealed that the patient, her father and siblings were PPD positive though chest screening and sputum examinations were negative in all of them. Lesion biopsy showed acute/chronic osteomyelitis with eosinophilia, tilting diagnosis towards eosinophilic granuloma/Hand–Schuller–Christian disease. Further investigations for diabetes insipidus, histiocytosis-X, skull–pelvic–femur radiographs, abdominal ultrasonography, ophthalmic consultation and PCR-TB test were negative. Histology, radiography, purified protein derivative (PPD)-positive result and history led to the diagnosis of primary TB of the mandible. Complete resolution occurred following antitubercular therapy. The case report emphasises that diagnosis of TB can sometimes be based on circumstantial evidence and positive response to antitubercular therapy even in view of a negative PCR result.
Patient safety during radiological examinations: a nationwide survey of residency training hospitals in Taiwan
Authors: Lee Yuan-Hao , Chen Clayton Chi-Chang , Lee San-Kan , Chen Cheng-Yu , Wan Yung-Liang , Guo Wan-Yuo , Cheng Amy , Chan Wing P
Published: September 2016

Objectives

Variations in radiological examination procedures and patient load lead to variations in standards of care related to patient safety and healthcare quality. To understand the status of safety measures to protect patients undergoing radiological examinations at residency training hospitals in Taiwan, a follow-up survey evaluating the full spectrum of diagnostic radiology procedures was conducted.

Design

Questionnaires covering 12 patient safety-related themes throughout the examination procedures were mailed to the departments of diagnostic radiology with residency training programmes in 19 medical centres (with >500 beds) and 17 smaller local institutions in Taiwan. After receiving the responses, all themes in 2014 were compared between medical centres and local institutions by using χ2or 2-sample t-tests.

Participants

Radiology Directors or Technology Chiefs of medical centres and local institutions in Taiwan participated in this survey by completing and returning the questionnaires.

Results

The response rates of medical centres and local institutions were 95% and 100%, respectively. As indicated, large medical centres carried out more frequent clinically ordered, radiologist-guided patient education to prepare patients for specific examinations (CT, 28% vs 6%; special procedures, 78% vs 44%) and incident review and analysis (89% vs 47%); however, they required significantly longer access time for MRI examinations (7.00±29.50 vs 3.50±3.50 days), had more yearly incidents of large-volume contrast-medium extravasation (2.75±1.00 vs 1.00±0.75 cases) and blank radiographs (41% vs 8%), lower monthly rates of suboptimal (but interpretable) radiographs (0.00±0.01% vs 0.64±1.84%) and high-risk reminder reporting (0.01±0.16% vs 1.00±1.75%) than local institutions.

Conclusions

Our study elucidates the status of patient safety in diagnostic radiology in Taiwan, thereby providing helpful information to improve patient safety guidelines needed for medical imaging in the future.
Smoking cessation care among patients with head and neck cancer: a systematic review
Authors: McCarter Kristen , Martínez Úrsula , Britton Ben , Baker Amanda , Bonevski Billie , Carter Gregory , Beck Alison , Wratten Chris , Guillaumier Ashleigh , Halpin Sean A , Wolfenden Luke
Published: September 2016

Objective

To examine the effectiveness of smoking cessation interventions in improving cessation rates and smoking related behaviour in patients with head and neck cancer (HNC).

Design

A systematic review of randomised and non-randomised controlled trials.

Methods

We searched the following data sources: CENTRAL in the Cochrane Library, MEDLINE, EMBASE, PsycINFO and CINAHL up to February 2016. A search of reference lists of included studies and Google Scholar (first 200 citations published online between 2000 and February 2016) was also undertaken. The methodological quality of included studies was assessed using the Effective Public Health Practice Project Quality Assessment Tool (EPHPP). 2 study authors independently screened and extracted data with disagreements resolved via consensus.

Results

Of the 5167 studies identified, 3 were eligible and included in the review. Trial designs of included studies were 2 randomised controlled trials and 1 non-randomised controlled trial. 2 studies received a weak methodological rating and 1 received a moderate methodological rating. The trials examine the impact of the following interventions: (1) nurse delivered cognitive–behaviour therapy (CBT) via telephone and accompanied by a workbook, combined with pharmacotherapy; (2) nurse and physician brief advice to quit and information booklets combined with pharmacotherapy; and (3) surgeon delivered enhanced advice to quit smoking augmented by booster sessions. Only the trial of the nurse delivered CBT and pharmacotherapy reported significant increases in smoking cessation rates. 1 study measured quit attempts and the other assessed consumption of cigarettes per day and readiness to change. There was no significant improvement in quit attempts or cigarettes smoked per day among patients in the intervention groups, relative to control.

Conclusions

There are very few studies evaluating the effectiveness of smoking cessation interventions that report results specific to the HNC population. The 3 trials identified reported equivocal findings. Extended CBT counselling coupled with pharmacotherapy may be effective.

Trial registration number

CRD42016016421.
Comparison of count-based multimorbidity measures in predicting emergency admission and functional decline in older community-dwelling adults: a prospective cohort study
Authors: Wallace Emma , McDowell Ronald , Bennett Kathleen , Fahey Tom , Smith Susan M
Published: September 2016

Objectives

Multimorbidity, defined as the presence of 2 or more chronic medical conditions in an individual, is associated with poorer health outcomes. Several multimorbidity measures exist, and the challenge is to decide which to use preferentially in predicting health outcomes. The study objective was to compare the performance of 5 count-based multimorbidity measures in predicting emergency hospital admission and functional decline in older community-dwelling adults attending primary care.

Setting

15 general practices (GPs) in Ireland.

Participants

n=862, ≥70 years, community-dwellers followed-up for 2 years (2010–2012).Exposure at baseline: Five multimorbidity measures (disease counts, selected conditions counts, Charlson comorbidity index, RxRisk-V, medication counts) calculated using GP medical record and linked national pharmacy claims data.

Primary outcomes

(1) Emergency admission and ambulatory care sensitive (ACS) admission (GP medical record) and (2) functional decline (postal questionnaire).

Statistical analysis

Descriptive statistics and measure discrimination (c-statistic, 95% CIs), adjusted for confounders.

Results

Median age was 77 years and 53% were women. Prevalent rates ranged from 37% to 91% depending on which measure was used to define multimorbidity. All measures demonstrated poor discrimination for the outcome of emergency admission (c-statistic range: 0.62, 0.65), ACS admission (c-statistic range: 0.63, 0.68) and functional decline (c-statistic range: 0.55, 0.61). Medication-based measures were equivalent to diagnosis-based measures.

Conclusions

The choice of measure may have a significant impact on prevalent rates. Five multimorbidity measures demonstrated poor discrimination in predicting emergency admission and functional decline, with medication-based measures equivalent to diagnosis-based measures. Consideration of multimorbidity in isolation is insufficient for predicting these outcomes in community settings.
Variations in GPs' decisions to investigate suspected lung cancer: a factorial experiment using multimedia vignettes
Authors: Sheringham Jessica , Sequeira Rachel , Myles Jonathan , Hamilton William , McDonnell Joe , Offman Judith , Duffy Stephen , Raine Rosalind
Published: September 2016

Introduction

Lung cancer survival is low and comparatively poor in the UK. Patients with symptoms suggestive of lung cancer commonly consult primary care, but it is unclear how general practitioners (GPs) distinguish which patients require further investigation. This study examined how patients' clinical and sociodemographic characteristics influence GPs' decisions to initiate lung cancer investigations.

Methods

A factorial experiment was conducted among a national sample of 227 English GPs using vignettes presented as simulated consultations. A multimedia-interactive website simulated key features of consultations using actors (‘patients’). GP participants made management decisions online for six ‘patients’, whose sociodemographic characteristics systematically varied across three levels of cancer risk. In low-risk vignettes, investigation (ie, chest X-ray ordered, computerised tomography scan or respiratory consultant referral) was not indicated; in medium-risk vignettes, investigation could be appropriate; in high-risk vignettes, investigation was definitely indicated. Each ‘patient’ had two lung cancer-related symptoms: one volunteered and another elicited if GPs asked. Variations in investigation likelihood were examined using multilevel logistic regression.

Results

GPs decided to investigate lung cancer in 74% (1000/1348) of vignettes. Investigation likelihood did not increase with cancer risk. Investigations were more likely when GPs requested information on symptoms that ‘patients’ had but did not volunteer (adjusted OR (AOR)=3.18; 95% CI 2.27 to 4.70). However, GPs omitted to seek this information in 42% (570/1348) of cases. GPs were less likely to investigate older than younger ‘patients’ (AOR=0.52; 95% CI 0.39 to 0.7) and black ‘patients’ than white (AOR=0.68; 95% CI 0.48 to 0.95).

Conclusions

GPs were not more likely to investigate ‘patients’ with high-risk than low-risk cancer symptoms. Furthermore, they did not investigate everyone with the same symptoms equally. Insufficient data gathering could be responsible for missed opportunities in diagnosis.
DSA-Dynavision in pretreatment planning for coil embolization of indirect carotid–cavernous fistula
Authors: Botsford Alex , Shankar Jai Jai Shiva
Published: September 2016

Introduction

Indirect carotid cavernous fistulas are treated with coil embolization when they present with orbital/visual symptoms or if there is cortical venous reflux. Most of the time, the treatment is done by non-specifically packing the whole cavernous sinus with coils. The purpose of this case series was to examine whether DSA-Dynavision before embolization would improve treatment by shortening the procedure time, requiring fewer coils, or reducing the complication rate.

Materials and method

8 patients with 9 fistula sites were retrospectively identified. DSA-Dynavision and non-DSA-Dynavision patients were compared in a retrospective cohort study.

Results

Mean total coil length was significantly shorter for the group who had DSA-Dynavision than for those who had non-DSA-Dynavision (130.5 cm vs 190 cm, p=0.034) and mean procedural time was significantly shorter for the DSA-Dynavision group (171.1 min vs 280.3 min, p=0.025). A transient neurological complication was seen in only one patient.

Conclusions

The use of DSA-Dynavision in pre-procedural planning facilitates selective coil embolization of the foot of the vein.
Use of neutrophil to lymphocyte ratio for predicting histopathological grade of canine mast cell tumours
Authors: Macfarlane M. J. , Macfarlane L. L. , Scase T. , Parkin T. , Morris J. S.
Published: September 2016

Canine mast cell tumours (MCTs) are variable in their biological behaviour and treatment decisions depend heavily on the histopathological grade. Biomarkers such as neutrophil to lymphocyte ratio (NLR) and albumin to globulin ratio are used to predict the biological behaviour of human neoplasms, but have not been widely studied in dogs. A retrospective analysis identified 62 cases of gross MCT (14 high‐grade, 48 low‐grade tumours). Median NLR was significantly different between high‐ and low‐grade MCT and tumours at different locations. A multivariable model identified increasing NLR (OR 2.0) and age (OR 1.7) to be associated with an increased risk of high‐grade MCT. Receiver operating characteristic curve analysis identified an NLR threshold value of 5.67 (sensitivity 85.7 per cent; specificity 54.2 per cent) for predicting a high‐grade MCT. An NLR threshold of 5.67 could be useful alongside existing tools (appearance, location, etc.) to help to predict the grade of MCT. With further validation, this biomarker could be used to guide clinical decisions before obtaining a histopathological diagnosis.
IMPACT OF CLIMATE CHANGE ON CHINA’S RICE PRODUCTION — AN EMPIRICAL ESTIMATION BASED ON PANEL DATA (1979–2011) FROM CHINA’S MAIN RICE-PRODUCING AREAS
Authors: WANG DAN , HAO YU , WANG JIANPEI
Published: September 2016

Climate change is attracting increasing attention from the international community. To assess the impact of climate change on China’s rice production, this paper re-organizes the main rice-producing areas by adding up the annual production of the provincial level regions between 1979 and 2011, utilizes Cobb–Douglas function using daily weather data over the whole growing season. Our analysis of the panel data shows that minimum temperatures (Tmin), maximum temperatures (Tmax), temperature difference (TD) and precipitation (RP) are the four key climate determinants of rice production in China. Among these, temperature difference is surprisingly significant and all except maximum temperatures have positive effects. However, because the actual minimum temperatures and precipitation in China’s main rice-producing areas declined while the maximum temperatures and the temperature difference increased during our sample period, climate change has actually provided a negative contribution to the increase in China’s rice production.
MONETARY SHOCKS AND STOCK MARKET FLUCTUATIONS: WITH AN APPLICATION TO THE CHINESE STOCK MARKET
Authors: ZHANG BO , HU JINYAN , JIANG MINGMING , GUO FENG
Published: September 2016

Using a simple theoretical model, this paper provides a micro-foundation of applying vector auto-regressive (VAR) models to explore the effects of monetary shocks on stock market fluctuations. We analytically show that, when monetary shocks change investors’ wealth and portfolio liquidity, their degree of risk aversion associated with wealth and liquidity changes accordingly, which is then channeled to their investment decision and finally to the stock market fluctuations. Both the wealth effect and liquidity effect of monetary shocks have inter-temporal impacts on stock pricing. Therefore, monetary shocks and stock price fluctuations should be treated as a unified vector system that is auto-correlated. Based on the theoretical analysis, this paper further studies the impacts of different forms of monetary shocks on the Chinese stock market over the period 2005 to 2012 with a non-linear VAR model. We find that monetary shocks in China have significant and asymmetric effects on the stock market performance over different market cycles. Our estimation suggests that changes in monetary policy may increase stock market volatility, even though these monetary policies are often aimed at stabilizing the Chinese macro-economic activities.
X-events and their interpretation
Authors: Corianò Claudio , Frampton Paul H.
Published: September 2016

We point out that when doubly-charged bileptons are pair produced at the LHC, kinematics dictate that they are both almost at rest in the lab frame and therefore their decays lead to final state muons in a characteristic X-shape with only very tiny track curvature because of the high muon energies. Such X-events have essentially no Standard Model background and provide a smoking gun for the 331 model.
The studies of the spin Hamiltonian parameters and local structures for various 3d3 hexacyanometallates of paramagnetic salts with diluents
Authors: Dong Hui-Ning , Liu Xu-Sheng , Zhou Hong-Fei
Published: September 2016

The spin Hamiltonian parameters (SHPs) ([Formula: see text] factors, hyperfine structure constants and zero-field splittings (ZFSs)) and local structures for various [Formula: see text] hexacyanometallates of paramagnetic salts K3Cr(CN)6 and K4V(CN)[Formula: see text]3H2O with the diluents K3Co(CN)6, K3Mn(CN)6 and K4Fe(CN)[Formula: see text]3H2O are theoretically investigated from the perturbation calculations of these parameters for a rhombically distorted octahedral [Formula: see text] cluster. The paramagnetic systems are found to undergo the local axial distortions [Formula: see text] [Formula: see text]0.19, −0.18 and 0.09 Å[Formula: see text] and the planar bond angle variations [Formula: see text] [Formula: see text] 3.5[Formula: see text], 5.3[Formula: see text] and 1.4[Formula: see text] for K3Cr(CN)6 with K3Co(CN)6, K3Cr(CN)6 with K3Mn(CN)6 and K4V(CN)[Formula: see text]3H2O with K4Fe(CN)[Formula: see text] 3H2O, respectively. The signs for ZFSs [Formula: see text] and [Formula: see text] are analyzed in the light of those for [Formula: see text] and the rhombic distortion angle [Formula: see text] [Formula: see text] related to an ideal octahedron. Microscopically, the magnitudes of [Formula: see text] and [Formula: see text] can be conveniently illustrated by the axial (ADD) and perpendicular distortion degrees (PDD), respectively, for the paramagnetic systems with the corresponding diluents. The local structural properties are analyzed from the relative ionic radius deviation [Formula: see text] of the equivalent diluent cation from the host paramagnetic cation, the axial and perpendicular ZFS variations [Formula: see text] and [Formula: see text] for ZFSs with the diluent related to the host, the relative deviation [Formula: see text]Dq of the cubic crystal-field parameter for the diluent related to the host. The above studies would be helpful to the investigations on synthesis, structures and properties of [Formula: see text] hexacyanometallates in paramagnetic salts.
Diffusion coefficients of nitric oxide in water: A molecular dynamics study
Authors: Pokharel Sunil , Pantha Nurapati , Adhikari N. P.
Published: September 2016

Self-diffusion coefficients along with the mutual diffusion coefficients of nitric oxide (NO) and SPC/E water (H2O) as solute and solvent of the mixture, have been studied within the framework of classical molecular dynamics level of calculations using GROMACS package. The radial distribution function (RDF) of the constituent compounds are calculated to study solute–solute, solute–solvent and solvent–solvent molecular interactions as a function of temperature. A dilute solution of five NO molecules (mole fraction 0.018) and 280 H2O molecules (mole fraction 0.982) has been taken as the sample. The self-diffusion coefficient of the solvent is calculated by using mean square displacement (MSD) where as that for solute (NO) is calculated by using MSD and velocity auto-correlation function (VACF). The results are then compared with the available experimental values. The results from the present work for water come in good agreement, very precise at low temperatures, with the experimental values. The diffusion coefficients of NO, on the other hands, agree well with the available theoretical studies, and also with experiment at low temperatures (up to 310 K). The results at the higher temperatures (up to 333 K), however, deviate significantly with the experimental observations. Also, the mutual diffusion coefficients of NO in water have been calculated by using Darken’s relation. The temperature dependence of the calculated diffusion coefficients follow the Arrhenius behavior.