bluuebunny/crossref_metadata_2025 huggingface dataset:
Particulate Matter Emission Comparison of Spark Ignition Direct Injection (SIDI) and Port Fuel Injection (PFI) Operation of a Boosted Gasoline Engine
Authors: Su Jianye , Lin Weiyang , Sterniak Jeff , Xu Min , Bohac Stanislav V.
Published: February 2014

Spark ignition direct injection (SIDI) gasoline engines, especially in downsized boosted engine platforms, are increasing their market share relative to port fuel injection (PFI) engines in U.S., European and Chinese vehicles due to better fuel economy by enabling higher compression ratios and higher specific power output. However, particulate matter (PM) emissions from engines are becoming a concern due to adverse human health and environment effects, and more stringent emission standards. To conduct a PM number and size comparison between SIDI and PFI systems, a 2.0 L boosted gasoline engine has been equipped and tested with both systems at different loads, air fuel ratios, spark timings, fuel pressures and injection timings for SIDI operation and loads, air fuel ratios and spark timings for PFI operation.

Regardless of load, air fuel ratio, spark timing, fuel pressure, and injection timing, particle size distribution from SIDI and PFI is shown to be bimodal, exhibiting nucleation and accumulation mode particles. SIDI produces particle numbers that are an order of magnitude greater than PFI. Particle number can be reduced by retarding spark timing and operating the engine lean, both for SIDI and PFI operation. Increasing fuel injection pressure and optimizing injection timing with SIDI also reduces PM emissions. This study provides insight into the differences in PM emissions from boosted SIDI and PFI engines and an evaluation of PM reduction potential by varying engine operating parameters in boosted SIDI and PFI gasoline engines.
Lower Compression Ring and Oil Control Ring Changes for Modern Diesel Engines
Authors: Bieneman Jason
Published: February 2014

The operating environment for piston rings in modern diesel engines continues to become more severe. Engine manufacturers are not only making changes to the engine to meet the government mandated emissions standards, but at the same time they are increasing both engine efficiencies and specific power levels. In order to meet these performance demands, Peak Cylinder Pressures (PCP) are increasing and piston compression heights are being reduced. These changes require significant upgrades to the Power Cylinder Unit (PCU), including piston and piston ring pack, as historic solutions no longer provide the robustness required for the next generation high output diesel engines.

Much attention has already been paid to improving top compression ring technology [1]. This paper will instead focus on how the lower compression ring and oil control ring are impacted by these increasing demands; as well as how design changes to these rings can help the engine manufacturers meet their performance goals. Changes to ring base material, ring face coatings, and running surface geometries will be explained along with a brief discussion about the influence of the ring’s boundary conditions and the changes that are simultaneously being made to surrounding components. These recommendations will be supported with bench test, simulations using the MIT ring pack code [2], and engine test results using numerous MDD/HDD engines.
Computational Analysis of Combustion of High and Low Cetane Fuels in a Compression Ignition Engine
Authors: Kavuri Chaitanya , Singh Satbir , Krishnan Sundar Rajan , Srinivasan Kalyan Kumar , Ciatti Stephen
Published: February 2014

Past research has shown that combustion of low cetane fuels in CI engines results in higher fuel conversion efficiencies. However, when high-cetane fuels like diesel are substituted with low-cetane fuels like gasoline, the engine operation tends to suffer from high CO emissions at low loads and combustion noise at high loads. In this paper, we present a computational analysis of a light-duty CI engine operating on diesel, kerosene and gasoline. These fuels cover a range of cetane numbers from 46 for diesel to 25 for gasoline. Similar to experiments, the model predicted higher CO at low load operation with gasoline. Predictions of in-cylinder details were utilized to understand differences in combustion characteristics of the three fuels. The in-cylinder mass contours and the evolution of model predicted in-cylinder mixture in Φ–T coordinates were then used to explain the emission trends. From the analysis, over-mixing due to early single injection was identified as the reason for high CO with low load gasoline Low Temperature Combustion (LTC). Additional simulations were performed by introducing techniques like cetane enhancement, adding hot EGR and variation of the injection scheme. Their effects on low load gasoline LTC were studied. Finally, it is shown that use of a dual pulse injection scheme with hot EGR helped to reduce the CO emissions for low load gasoline LTC while maintaining low NOx emissions.
Artificial Neural Network for Predicting Cetane Number of Biofuel Candidates Based on Molecular Structure
Authors: Sennott T. , Gotianun C. , Serres R. , Ziabasharhagh M. , Mack J. H. , Dibble R.
Published: February 2014

The production of next-generation biofuels is being explored through a variety of chemical and biological approaches, all aiming at lowering costs and increasing yields while producing viable alternatives to gasoline or diesel fuel. Chemical synthesis can lead to a huge variety of different fuels and the guidelines from which molecules yield desirable properties as a fuel are largely based on intuition. One such property of interest is the cetane number (CN), a measure of the ignition quality of diesel fuel. The present work improves on existing models and extends them to more oxygenates (primarily ethers) to increase the model’s generalizability to the large variety of new potential biofuels currently of interest to researchers. This predictive model uses artificial neural networks (ANN’s) as a tool for quantitative structure property relationship (QSPR) analysis. Predicting the cetane number of a fuel is especially important because testing a fuel requires large volumes of pure sample (100mL for derived cetane number, >1L for cetane number), the production of which can be difficult, costly and time-consuming at the lab scale. To this end, a predictive model will allow chemists to eliminate unlikely targets and focus their attention on promising candidates.
Study of Performance Characteristics of Opposed-Piston Folded-Cranktrain Engines
Authors: Zhao Zhenfeng , Zhang Fujun , Huang Ying , Zhang Zhenyu , Wu Dan
Published: February 2014

This paper discusses a prototype of horizontally opposed-piston folded-cranktrain two-stroke diesel engine with combined supercharger and high-pressure common rail fuel system by Beijing Institute of Technology. The cranktrain dynamics, the thermodynamics (include the combustion process and the scavenging) are investigated, which is the main difference between this type of engine and conventional engines. The aim of the work is to design and develop a prototype of opposed-piston folded-cranktrain engine. The investigated results showed that maximum speeds of two pistons are all 13.99m/s, while the mean velocity is 9.4 m/s; the maximum acceleration on negative side is 3765 m/s2 when the piston is near the BDC and the maximum acceleration on positive side is 2944 m/s2 when the pistons is near the TDC; scavenging efficiency can get to 89% and the final air utilization is 55%.

The prototype of opposed-piston folded-cranktrain engine has been developed.
Assessment of Different Cavitation Models in Mixture and Eulerian Framework for Two-Phase Flow in Diesel Injectors
Authors: Saha Kaushik , Li Xianguo
Published: February 2014

A comparative study using different cavitation models in mixture and Eulerian framework is carried out for the analysis of two-phase flows in diesel injectors. Three different cavitation models are investigated here: recently developed modified single-fluid, Schnerr-Sauer and Zwart-Gerber-Belamri models. The last two models have been implemented in both mixture and Eulerian framework. The numerical predictions are compared both qualitatively and quantitatively with experimental results available in the literature. Qualitative assessments have been carried out with experimental images of two-phase flow in an optically accessible nozzle. Quantitative comparisons have been done with measured mass flow rates and velocity profiles. It appears that at low pressure differentials there can be considerable discrepancy in the predictions of the vapour distribution from the three models considered. The modified single-fluid approach turns out to be comparatively better with respect to the other two models. Implementation in mixture and Eulerian framework yields noticeable differences in the results because of the relative velocity of the two phases. Numerical experiments have been carried out with different two-phase turbulence modelling approaches, pressure-velocity coupling algorithms, gradient calculation methods and under-relaxation factors to assess the robustness of the models. Additionally comparisons have been carried out for conditions under high inlet pressure in an axisymmetric nozzle to understand the performance of the models under realistic operating conditions.
A Study on Biodiesel NOx Emission Control With the Reduced Chemical Kinetics Model
Authors: Li Juncheng , Lee Chia-fon F. , Han Zhiyu , Shen Cai , Wang Mianzhi
Published: February 2014

In this paper, the effects of the start of injection (SOI) timing and EGR rate on the nitrogen oxide (NOx) emissions of biodiesel-powered diesel engine are studied with computational fluid dynamics (CFD) coupling with a chemical kinetics model. A surrogate biodiesel mechanism consisting of two fuel components is employed as the combustion model of soybean biodiesel. The in-cylinder combustion processes of the cases with four injection timings and three exhaust gas recirculation (EGR) rates are simulated. The simulation results show that the NOx emissions of biodiesel combustion can be effectively improved by SOI retardation or increasing EGR rate. The calculated NOx emissions of the cases with default EGR rate are reduced by 20.3% and 32.9% when the injection timings are delayed by 2-degree and 4-degree crank angle, respectively. The calculated NOx emissions of the cases with 24.0% and 28.0% EGR are reduced by 38.4% and 62.8%, respectively, compared to that of the case with default SOI and 19.2% EGR. But higher EGR rate deteriorates the soot emission. When EGR rate is 28.0% and SOI is advanced by 2-degree, the NOx emission is reduced by 55.1% and soot emission is controlled as that of the case with 24% EGR and default SOI.
Comparison of 1-D vs 3-D Combustion Boundary Conditions for SI Engine Thermal Load Prediction
Authors: Iqbal O. , Jonnalagedda S. , Arora K. , Zhong L. , Gaikwad S.
Published: February 2014

The thermal field generated in an engine block and cylinder head as a result of combustion loading is of paramount significance for structural durability. Computational fluid dynamics and heat transfer modeling provide strong tools; perhaps the best and most precise available for predicting thermal fields within cylinder head and engine block. However, an enduring challenge has been the temperature prediction on metal wall as a response to the time dependent fluctuations in the fluids. Fluid (coolant) flow in an engine is steady for a given engine speed and load, but combustion dynamics are inherently transient. In this study, an effective set of convective boundary condition data (as combustion load) is generated using two different approaches in a stand-alone simulation and mapped onto a decoupled Conjugate Heat Transfer (CHT) model to predict the temperature distribution in the engine.

In the first approach, a predictive combustion model, tuned to dyno test data, is solved in a 1-D simulation code. This provides the cycle-averaged convective boundary condition that can be used for a CHT model as a uniform heat source. In the second, more detailed approach, in-cylinder combustion simulations involving transient piston and valve motion with flame propagation modeling are carried out using a 3-D simulation code. The 3-D methodology gives a detailed distribution of convective boundary conditions on the walls touching the combustion gases. In order to predict the gradients in heat transfer coefficient with high accuracy, the resulting temperature distribution from the CHT simulation is fed back into the combustion model to regenerate the set of convective boundary conditions. This process is repeated until a converged set of convective boundary conditions are obtained.

In this paper engine temperature predictions obtained using combustion loads from both 1-D and 3-D approaches will be compared with the thermocouple data from engine dyno test.
Simulation of n-Heptane and Surrogate Fuels for Advanced Combustion Engines (FACE) in a Single-Cylinder Compression Ignition Engine
Authors: Taglialegami Joseph , Bogin Gregory , Osecky Eric , Dean Anthony M.
Published: February 2014

A CFD model of a HATZ diesel engine was developed for the purpose of simulating low temperature combustion (LTC) of surrogate diesel fuels for the Fuels for Advanced Combustion Engines (FACE). Initial validation of the model was performed using n-heptane data from a single cylinder HATZ diesel engine. Simulations were run with both a detailed n-heptane mechanism and several reduced mechanisms to determine the suitability of using a reduced mechanism to capture the main ignition characteristics and emissions. It was found that a 173 species n-heptane mechanism predicts start of combustion (SOC) within 0.5 crank angle degrees of the detailed 561 species mechanism. The 173 species mechanism required 27 hours of computational time to reach the end of the simulation whereas the 561 species detailed mechanism required 41 hours under the same conditions. Two additional reduced mechanisms, containing 85 and 35 species, were provided reasonable accuracy with a computational time of 8 hours and 2 hours, respectively. Due to the varying physical and chemical properties of the FACE surrogates, a sensitivity analysis of the effects of the physical properties was conducted by changing the n-heptane physical properties to those of n-hexadecane while keeping the chemistry the same. As expected, when the fuel properties of n-hexadecane (which is less volatile than n-heptane) were used with the n-heptane kinetics, SOC was delayed and the net heat release rate was reduced.

The FACE fuels were developed to fulfill the need for research grade fuels that are able to represent common refinery stream fuels. Since the FACE fuels consist of hundreds of fuel components, it is not feasible to model the actual FACE fuels in a full-scale engine model. An alternative is to develop surrogates consisting of relatively few species for which detailed mechanisms are available. Even then this mechanism would need to be reduced to make the computation practical. For this work, a detailed diesel surrogate mechanism was reduced from 4016 species to 1046 species to match the characteristics for FACE fuels 1, 3, 5, 8, and 9. The surrogates only contain 4–7 species. Using the single chemical mechanism to represent five surrogate FACE fuels, it was found that ∼200°C of air preheat was required to achieve autoignition in the HATZ model compared to the 130°C of air preheat required experimentally. Initial runs have found that there were similar trends in SOC and heat release between the FACE fuel surrogate experiments and simulations for the respective fuels. Future work will require improvements on the single chemical mechanism to represent the five surrogate FACE fuels.
Joan of Arc in New Age Spirituality
Authors: Kavan Heather
Published: February 2014

This paper explores New Age interpretations of Joan of Arc, both as a fifteenth-century woman and as a spiritual being. The central focus is on messages believed to be from Joan (or “Jeanne”), channeled by Starla Hinman. I analyze the content and impact of these messages, and conclude that a new archetype of Joan has emerged—as a woman of the future who can positively transform the world. Additionally, I discuss five ways in which spiritual seekers perceive Joan today: as a mystic, an ascended master, a personification of the divine feminine, a torch-bearer of the Holy Grail, and the embodiment of Michaelic and Marian essences
Historiography and New Religious Movements: The Case of Modern Italian Witchcraft
Authors: Stella Federico
Published: February 2014

I examine the influence of historiography on neo-Paganism and in particular on modern Italian witchcraft. I show how historiographical narratives have influenced some aspects of contemporary religious ideology, particularly the case of the influence of the theses of Charles Godfrey Leland and Margaret Alice Murray on the doctrine of modern Italian witchcraft. The appendix records an interview with an anonymous Italian writer on witchcraft, Dragon Rouge
Responsive and “smart” antibacterial surfaces: Common approaches and new developments (Review)
Authors: Cavallaro Alex , Taheri Shima , Vasilev Krasimir
Published: February 2014

Bacterial infections are continuing to pose a significant threat to human health. Coatings with inherent antibacterial properties are becoming increasingly common as an infection preventative measure. The aim of this review is to highlight recent progress in development of “smart” and responsive antibacterial surfaces. The review describes various strategies utilized for generation of such surfaces and the specific stimuli that are used to trigger antibacterial action. It also provides a critical discussion of the advantages and drawbacks of different approaches. The review concludes with a perspective about the future of the field and outlines the challenges and obstacles that need to be overcome in order to make future advances.
Mammographic quantitative image analysis and biologic image composition for breast lesion characterization and classification
Authors: Drukker Karen , Duewer Fred , Giger Maryellen L. , Malkov Serghei , Flowers Chris I. , Joe Bonnie , Kerlikowske Karla , Drukteinis Jennifer S. , Li Hui , Shepherd John A.
Published: February 2014

Purpose:

To investigate whether biologic image composition of mammographic lesions can improve upon existing mammographic quantitative image analysis (QIA) in estimating the probability of malignancy.

Methods:

The study population consisted of 45 breast lesions imaged with dual‐energy mammography prior to breast biopsy with final diagnosis resulting in 10 invasive ductal carcinomas, 5 ductal carcinomain situ, 11 fibroadenomas, and 19 other benign diagnoses. Analysis was threefold: (1) The raw low‐energy mammographic images were analyzed with an established in‐house QIA method, “QIA alone,” (2) the three‐compartment breast (3CB) composition measure—derived from the dual‐energy mammography—of water, lipid, and protein thickness were assessed, “3CB alone”, and (3) information from QIA and 3CB was combined, “QIA + 3CB.” Analysis was initiated from radiologist‐indicated lesion centers and was otherwise fully automated. Steps of the QIA and 3CB methods were lesion segmentation, characterization, and subsequent classification for malignancy in leave‐one‐case‐out cross‐validation. Performance assessment included box plots, Bland–Altman plots, and Receiver Operating Characteristic (ROC) analysis.

Results:

The area under the ROC curve (AUC) for distinguishing between benign and malignant lesions (invasive and DCIS) was 0.81 (standard error 0.07) for the “QIA alone” method, 0.72 (0.07) for “3CB alone” method, and 0.86 (0.04) for “QIA+3CB” combined. The difference in AUC was 0.043 between “QIA + 3CB” and “QIA alone” but failed to reach statistical significance (95% confidence interval [–0.17 to + 0.26]).

Conclusions:

In this pilot study analyzing the new 3CB imaging modality, knowledge of the composition of breast lesions and their periphery appeared additive in combination with existing mammographic QIA methods for the distinction between different benign and malignant lesion types.
Efficacy of fixed filtration for rapid kVp‐switching dual energy x‐ray systems
Authors: Yao Yuan , Wang Adam S. , Pelc Norbert J.
Published: February 2014

Purpose:

Dose efficiency of dual kVp imaging can be improved if the two beams are filtered to remove photons in the common part of their spectra, thereby increasing spectral separation. While there are a number of advantages to rapid kVp‐switching for dual energy, it may not be feasible to have two different filters for the two spectra. Therefore, the authors are interested in whether a fixed added filter can improve the dose efficiency of kVp‐switching dual energy x‐ray systems.

Methods:

The authors hypothesized that a K‐edge filter would provide the energy selectivity needed to remove overlap of the spectra and hence increase the precision of material separation at constant dose. Preliminary simulations were done using calcium and water basis materials and 80 and 140 kVp x‐ray spectra. Precision of the decomposition was evaluated based on the propagation of the Poisson noise through the decomposition function. Considering availability and cost, the authors chose a commercial Gd2O2S screen as the filter for their experimental validation. Experiments were conducted on a table‐top system using a phantom with various thicknesses of acrylic and copper and 70 and 125 kVp x‐ray spectra. The authors kept the phantom exposure roughly constant with and without filtration by adjusting the tube current. The filtered and unfiltered raw data of both low and high energy were decomposed into basis material and the variance of the decomposition for each thickness pair was calculated. To evaluate the filtration performance, the authors measured the ratio of material decomposition variance with and without filtration.

Results:

Simulation results show that the ideal filter material depends on the object composition and thickness, and ranges across the lanthanide series, with higher atomic number filters being preferred for more attenuating objects. Variance reduction increases with filter thickness, and substantial reductions (40%) can be achieved with a 2× loss in intensity. The authors’ experimental results validate the simulations, yet were overall slightly worse than expectation. For large objects, conventional (non‐K‐edge) beam hardening filters perform well.

Conclusions:

This study demonstrates the potential of fixed K‐edge filtration to improve the dose efficiency and material decomposition precision for rapid kVp‐switching dual energy systems.
Combining Internal- and External-Training-Load Measures in Professional Rugby League
Authors: Weaving Dan , Marshall Phil , Earle Keith , Nevill Alan , Abt Grant
Published: February 2014

Purpose:

This study investigated the effect of training mode on the relationships between measures of training load in professional rugby league players.

Methods:

Five measures of training load (internal: individualized training impulse, session rating of perceived exertion; external—body load, high-speed distance, total impacts) were collected from 17 professional male rugby league players over the course of two 12-wk preseason periods. Training was categorized by mode (small-sided games, conditioning, skills, speed, strongman, and wrestle) and subsequently subjected to a principal-component analysis. Extraction criteria were set at an eigenvalue of greater than 1. Modes that extracted more than 1 principal component were subjected to a varimax rotation.

Results:

Small-sided games and conditioning extracted 1 principal component, explaining 68% and 52% of the variance, respectively. Skills, wrestle, strongman, and speed extracted 2 principal components each explaining 68%, 71%, 72%, and 67% of the variance, respectively.

Conclusions:

In certain training modes the inclusion of both internal and external training-load measures explained a greater proportion of the variance than any 1 individual measure. This would suggest that in training modes where 2 principal components were identified, the use of only a single internal or external training-load measure could potentially lead to an underestimation of the training dose. Consequently, a combination of internal- and external-load measures is required during certain training modes.
Six Weeks of Unsupervised Nintendo Wii Fit Gaming Is Effective at Improving Balance in Independent Older Adults
Authors: Nicholson Vaughan Patrick , McKean Mark , Lowe John , Fawcett Christine , Burkett Brendan
Published: February 2014

Objective:

To determine the effectiveness of unsupervised Nintendo Wii Fit balance training in older adults.

Methods:

Forty-one older adults were recruited from local retirement villages and educational settings to participate in a six-week two-group repeated measures study. The Wii group (n = 19, 75 ± 6 years) undertook 30 min of unsupervised Wii balance gaming three times per week in their retirement village while the comparison group (n = 22, 74 ± 5 years) continued with their usual exercise program. Participants’ balance abilities were assessed pre- and postintervention.

Results:

The Wii Fit group demonstrated significant improvements (P < .05) in timed up-and-go, left single-leg balance, lateral reach (left and right), and gait speed compared with the comparison group. Reported levels of enjoyment following game play increased during the study.

Conclusion:

Six weeks of unsupervised Wii balance training is an effective modality for improving balance in independent older adults.
On-Field Signs and Symptoms Associated With Recovery Duration After Concussion in High School and College Athletes: A Critically Appraised Topic
Authors: Shim Jaebin , Smith Deanna H. , Van Lunen Bonnie L.
Published: February 2014

Clinical Scenario:

Over the past decade, sport-related concussions have received increased attention due to their frequency and severity over a wide range of athletics. Clinicians have developed return-to-play protocols to better manage concussions in young athletes; however, a standardized process projecting the length of recovery time after concussion has remained an elusive piece of the puzzle. The recovery times associated with such an injury once diagnosed can last anywhere from 1 wk to several months. Risk factors that could lead to protracted recovery times include a history of 1 or multiple concussions and a greater number, severity, and duration of symptoms after the injury. Examining the possible relationship between on-field or sideline signs and symptoms and recovery times would give clinicians the confident ability to properly treat and manage an athlete’s recovery process in a more systematic manner. Furthermore, identifying factors after a head injury that may be predictive of protracted recovery times would be useful for athletes, parents, and coaches alike.

Focused Clinical Question:

Which on-field and sideline signs and symptoms affect length of recovery after concussion in high school and college athletes?
Draft Genome Sequence of
Pedobacter
sp. Strain V48, Isolated from a Coastal Sand Dune in the Netherlands
Authors: Bitzer Adam S. , Garbeva Paolina , Silby Mark W.
Published: February 2014

Pedobacter
sp. strain V48 participates in an interaction with
Pseudomonas fluorescens
which elicits interaction-induced phenotypes. We report the draft genome sequence of
Pedobacter
sp. V48, consisting of 6.46 Mbp. The sequence will contribute to improved understanding of the genus and facilitate genomic analysis of the model interspecies interaction with
P. fluorescens
.
Whole-Genome Sequence of Muju Virus, an Arvicolid Rodent-Borne Hantavirus
Authors: Lee Jin Goo , Gu Se Hun , Baek Luck Ju , Shin Ok Sarah , Kim Heung-Chul , Klein Terry A. , Yanagihara Richard , Song Jin-Won
Published: February 2014

The complete genome sequence of Muju virus was determined from lung tissue samples of three royal voles (
Myodes regulus
) captured in Gangwon province in the Republic of Korea. Since few whole genome sequences of hantaviruses are available, this sequence may help to clarify the molecular phylogeny of arvicolid rodent-borne hantaviruses.
Idiopathic left ventricular apical hypoplasia
Authors: Raza Ali , Waleed Mohammad , Balerdi Matthew , Bragadeesh Thanjavur , Clark Andrew L
Published: February 2014

A 46-year-old man was found to have an abnormal ECG taken during a routine health and blood pressure check. His only symptom was non-specific central chest discomfort, unrelated to exertion. His ECG showed sinus rhythm, a normal axis and poor R wave progression across the chest leads and lateral T wave flattening. An echocardiogram showed a dilated left ventricle with a thin and hypokinetic septum bulging to the right. The apex was ‘not well seen’ but also appeared thin and hypokinetic. The right heart and valves were normal. The patient was further investigated for left ventricular hypoplasia.
Prevalence and trend of dyslipidaemia from 1996 to 2006 among normal and overweight adolescents in Taiwan
Authors: Kuo Philip , Syu Jhu-Ting , Tzou Isabel Lin , Chen Pi-Yun , Su Hsiu-Yueh , Chu Nain-Feng
Published: February 2014

Objectives

To evaluate the trend of dyslipidaemia from 1996 to 2006 and examine its relationship with weight status among adolescents in Taiwan.

Design

2 cross-sectional surveys were conducted in 1996 and 2006.

Setting

The junior high schools in Taipei.

Participants

After multistage sampling, total of 1500 and 1283 junior high school students were chosen in 1996 and 2006. After excluding missing data, a total of 1353 (676 boys and 677 girls) and 1203 (585 boys and 618 girls) children were included in the final analyses in 1996 and 2006.

Outcome measures

Anthropometric measures as body height and weight were measured, and body mass index (BMI) was calculated. Blood lipid profiles as total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol were measured.

Results

From 1996 to 2006, the prevalence of dyslipidaemia and hypercholesterolaemia significantly increased from 13% (95% CI 11.3% to 15.0%) to 22.3% (95% CI 20.0% to 24.7%) and 6.2% (95% CI 5.0% to 7.6%) to 13.8% (95% CI 11.9% to 15.9%), respectively. The prevalence of hypertriglyceridaemia and low HDL-C dyslipidaemia increased from 3% (95% CI 1.8% to 4.5%) to 4.3% (95% CI 2.8% to 6.2%) and 6.5% (95% CI 4.8% to 8.6%) to 11.6% (95% CI 9.1% to 14.5%), with significance seen only in boys. When compared with normal weight participants, overweight boys and girls faced a 2-fold and 1.6-fold increased risk of dyslipidaemia, respectively, in the 2006 study. The increased risk of low HDL-C dyslipidaemia for overweight participants was 2.6-fold and 7.2-fold in boys and girls, respectively. In 2006, each unit increment of BMI was associated with 28%, 13% and 13% risk of hypertriglyceridaemia, low HDL-C and dyslipidaemia for boys, and 25% risk of low HDL-C dyslipidaemia in girls.

Conclusions

The prevalence of dyslipidaemia had increased significantly for boys and girls in normal weight and overweight adolescents. Early screening of dyslipidaemia and weight intervention programmes in adolescents will be the key to prevent dyslipidaemia and cardiovascular-related comorbidities.
Warfarin treatment among Finnish patients with atrial fibrillation: retrospective registry study based on primary healthcare data
Authors: Hallinen Taru , Soini Erkki J , Asseburg Christian , Kuosmanen Pekka , Laakkonen Ari
Published: February 2014

Objective

To assess the frequency of warfarin use, the achieved international normalised ratio (INR) balance among warfarin users and the primary healthcare outpatient costs of patients with atrial fibrillation (AF).

Design

Retrospective, non-interventional registry study.

Setting

Primary healthcare.

Participants

All patients with AF (n=2746) treated in one Finnish health centre between October 2010 and March 2012.

Methods

Data on healthcare resource use, warfarin use, individually defined target INR range and INR test results were collected from the primary healthcare database for patients with AF diagnosis. The analysed dataset consisted of a 1-year follow-up. Warfarin treatment balance was estimated with the proportion of time spent in the therapeutic INR range (TTR). The cost of used healthcare resources was valued separately with national and service provider unit costs to estimate the total outpatient treatment costs. The factors potentially impacting the treatment costs were assessed with a generalised linear regression model.

Results

Approximately 50% of the patients with AF with CHADS-VASc ≥1 used warfarin. The average TTR was 65.2% but increased to 74.5% among patients using warfarin continuously (ie, without gaps exceeding 56 days between successive INR tests) during follow-up. One-third of the patients had a TTR of below 60%. The average outpatient costs in the patient cohort were €314.44 with the national unit costs and €560.26 with the service provider unit costs. The costs among warfarin users were, on average, €524.11 or €939.54 higher compared with the costs among non-users, depending on the used unit costs. A higher TTR was associated with lower outpatient costs.

Conclusions

The patients in the study centre using warfarin were, on average, well controlled on warfarin, yet one-third of patients had a TTR of below 60%.
Association of serum alkaline phosphatase with mortality in non-selected European patients with CKD5D: an observational, three-centre survival analysis
Authors: Beige Joachim , Wendt Ralph , Girndt Matthias , Queck Karl-Heinz , Fiedler Roman , Jehle Peter
Published: February 2014

Objectives

For characterisation of mineral bone disease in chronic kidney disease (CKD), laboratory surrogates have been suggested. This observational should investigate the association of total and skeletal alkaline phosphatase (AP) with mortality of patients undergoing maintenance renal replacement therapy.

Setting

Three renal outpatient centers in eastern-central Germany (secondary and tertiary care).

Participants

Complete survival and laboratory datasets were available in 407 of 493 patients. Age and gender distribution was equivalent to a general population with end-stage CKD (CKD5D). Patients were included between 2008 and 2010 if at least 2 weeks of maintenance treatment were documented.

Primary outcome measures

Mortality was estimated by setting theend of dialysis dateas event date. Events other than death (change to another centre, life-sustaining renal function or transplantation) were censored.

Results

The OR to die within follow-up for patients in the higher of two total AP strata was 2.70 (95% CI 1.76 to 4.15). In univariateKaplan-Meieranalysis, total AP had a strong association with all-cause mortality (LogRank=24.1, p<0.001). Mean total AP and individual lowest skeletal AP, but not mean skeletal AP entered step-wiseCoxmodels for survival from dialysis start (χ2=22.4; p<0.001) after adjusting for age, Kt/V, diabetes and vintage. Mean values of skeletal, total AP and parathyroid hormone were 14.8±8.9 µg/L, 91.9±55.3 U/L and 188±164 ng/L, respectively. Skeletal and total AP were highly correlated (R=0.86; p<0.001).

Conclusions

This unselected CKD5D population exhibited a clinical significant association of total AP with crude mortality and a stronger death risk association of total AP and individual lowest skeletal AP with crude mortality.
Measuring Armenia's progress on the Tobacco Control Scale: an evaluation of tobacco control in an economy in transition, 2005–2009
Authors: Movsisyan Narine K , Connolly Gregory N
Published: February 2014

Objectives

This study aimed to measure the 5-year progress in the implementation of WHO Framework Convention on Tobacco Control (FCTC) in Armenia by applying the Tobacco Control Scale, a rapid assessment tool developed to assess the strength of tobacco control policies in Europe.

Setting

Armenia, an economy in transition, has extreme smoking rates among men (62.5%) despite acceding to FCTC in 2004. However, little research has been carried out to evaluate Armenia's progress in tobacco control.

Methods

The Tobacco Control Scale total score was estimated for Armenia using the original methodology; however, a different source of data was used in estimating the subscores on tobacco price and tobacco control spending.

Results

Armenia's total score on Tobacco Control Scale has considerably improved from 2005 to 2009, mostly due to larger health warnings and advertising ban, and increased public spending on tobacco control. The scores for smoke-free public places, advertising ban, health warnings and treatment categories were below the European average in 2005 and 2007, while the price score was higher. Neither total tobacco control score nor any of its components showed a significant predictive value in a simple regression analysis using the total score and subscores as predictors for log-transformed per capita tobacco consumption.

Conclusions

Higher than the European average price score for Armenia cannot be explained by the concept of affordability alone and may reflect a measurement error due to peculiarities of transition economies. The applicability of the Tobacco Control Scale could be limited to countries with mature economies, but not to transition countries such as Armenia with different social, political and economic environment. The scale modification, such as an adjustment for the policy enforcement and the effectiveness of public tobacco control spending along with alternative measures of affordability would be warranted to enhance its applicability in low-income and middle-income countries.
Benefits and barriers to participation in colorectal cancer screening: a protocol for a systematic review and synthesis of qualitative studies
Authors: Honein-AbouHaidar Gladys N , Kastner Monika , Vuong Vincent , Perrier Laure , Rabeneck Linda , Tinmouth Jill , Straus Sharon , Baxter Nancy N
Published: February 2014

Introduction

Colorectal cancer (CRC) poses a serious health problem worldwide. While screening is effective in reducing CRC mortality, participation in screening tests is generally suboptimal and social inequities in participation are frequently reported. The goal of this review is to synthesise factors that influence an individual’s decision to participate in CRC screening, and to explore how those factors vary by sex, ethnicity and socioeconomic status.

Data sources

A primary search of Cumulative Index to Nursing and Allied Health Literature (CINAHL), MEDLINE, EMBASE, PsycINFO, and a secondary search of grey literature and articles taken from references of included articles (from inception to July 2013).

Design

A systematic review and Meta-study synthesis of qualitative studies that address perceived benefits and barriers to participation in CRC screening tests among adults 50 years of age or older.

Review methods

The two-staged Meta-study methodology by Paterson will be used to conduct this review. In stage 1, similarities/differences, patterns and themes will be identified across three levels of analysis while preserving the context of original studies. In stage 2, synthesis will extend beyond the analysis to generate new theory of the phenomenon through a process called Meta-synthesis.

Discussion

This review offers to generate a framework to better understand benefits and barriers that affect decision-making to participate in CRC screening among different sectors of the population. This framework will be a relevant tool for policy makers in framing educational materials, for patient-centered communication, and for researchers interested in the science of equity. This review is registered in PROSPERO (registration number: CRD42013005025).
Evidence-based clinical practice for the neurointerventionalist
Authors: Hirsch Joshua A , Turk Aquilla S , Mocco J , Fiorella David J , Jayaraman Mahesh V , Meyers Phillip M , Yoo Albert J , Manchikanti Laxmaiah
Published: February 2014

The field of neurointerventional (NI) surgery has developed in the context of technologic innovation. Many treatments readily provided in 2014 would have been hard to imagine as recently as 10 years ago. The reality of present day NI care is that, while providers, payors, policy makers and patients rely on evidence to guide NI decision-making, the available data are often less robust than participants might desire. In this paper we will explore the fundamentals of evidence-based clinical practice.
Asymptomatic left ventricular dysfunction with long-term clozapine treatment for schizophrenia: a multicentre cross-sectional cohort study
Authors: Chow V , Yeoh T , Ng A C C , Pasqualon T , Scott E , Plater J , Whitwell B , Hanzek D , Chung T , Thomas L , Celermajer D S , Kritharides L
Published: February 2014

Objectives

Patients with schizophrenia treated with clozapine are at risk of acute myocarditis and dilated cardiomyopathy. However, there are no data on the prevalence of subclinical cardiomyopathy or its associations.

Methods

100 consecutive patients with schizophrenia treated with clozapine for >1 year and without a history of cardiac pathology (group 1), 21 controls with a history of schizophrenia treated with non-clozapine antipsychotics for >1 year (group 2) and 20 controls without schizophrenia (group 3) were studied. Comprehensive evaluation by clinical examination, ECG, transthoracic echocardiography including left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) and biochemical profiles were performed.

Results

Patients with schizophrenia were of similar age, but had higher body mass index (BMI), rates of smoking and hyperlipidaemia than controls. Patients with schizophrenia had received clozapine or non-clozapine antipsychotics for a mean duration of 6.8±5.3 and 9.7±6.1 years, respectively. Patients taking clozapine demonstrated globally impaired LVEF (58.3%: group 1 vs 62.2%: group 2 vs 64.8%: group 3, p<0.001) and GLS (−16.7%: group 1 vs −18.6%: group 2 vs −20.2%: group 3, p<0.001). Moreover, LVEF was <50% in 9/100 (9%) patients receiving clozapine and in non-clozapine schizophrenia patients or healthy controls, but this was not statistically significantly different (analysis of covariance, p=0.19). Univariate analysis in patients taking clozapine found that impaired LV was not predicted by high-sensitivity troponin T, but was associated with features of the metabolic syndrome (including increased triglycerides, low high-density lipoprotein cholesterol (HDL-C), high-sensitivity C reactive protein and BMI), elevated neutrophil count, elevated heart rate, smoking and N-terminal probrain natriuretic peptide. In patients taking clozapine, multivariable analysis identified elevated neutrophil count and low HDL-C as the only independent predictors of impaired GLS.

Conclusions

Asymptomatic mild LV impairment is common in patients with schizophrenia receiving long-term clozapine treatment and is associated with neutrophilia and low HDL-C.
Medical student views on the use of Facebook profile screening by residency admissions committees
Authors: George Daniel R , Green Michael J , Navarro Anita M , Stazyk Kelly K , Clark Melissa A
Published: February 2014

Purpose

Previous research has shown that >50% of residency programmes indicate that inappropriate Facebook postings could be grounds for rejecting a student applicant. This study sought to understand medical students’ views regarding the impact of their Facebook postings on the residency admissions process.

Study design

In 2011–2012, we conducted a national survey of 7144 randomly selected medical students representing 10% of current enrollees in US medical schools. Students were presented with a hypothetical scenario of a residency admissions committee searching Facebook and finding inappropriate pictures of a student, and were asked how the committee ought to regard these pictures.

Results

The response rate was 30% (2109/7144). Respondents did not differ from medical students nationally with regard to type of medical school and regional representation. Of the three options provided, the majority of respondents (63.5%) indicated ‘the pictures should be considered along with other factors, but should not be grounds for automatic rejection of the application’. A third (33.7%) believed ‘the pictures should have no bearing on my application; the pictures are irrelevant’. A small minority of respondents (2.8%) felt ‘the pictures should be grounds for automatic rejection of the application’.

Conclusions

That the views of students regarding the consequences of their online activity differ so greatly from the views of residency admissions committees speaks to the need for better communication between these parties. It also presents opportunities for medical schools to help students in their residency application process by increasing awareness of social media screening strategies used by some residency programmes, and fostering self-awareness around the use of social media during medical school and especially during the residency application process.
Decreased serum protein associated with Mycobacterium avium subspecies paratuberculosis shedding in German Holstein cows
Authors: Donat K. , Erhardt G. , Soschinka A. , Brandt H. R.
Published: February 2014

Using well established metabolic parameters, this study aimed to substantiate differences in protein and energy metabolism between Mycobacterium avium subspecies paratuberculosis (MAP) positive and negative dairy cows tested by faecal culture. A total of 227 MAP‐positive and 239 MAP‐negative German Holstein cows kept in 13 MAP‐positive dairy herds were selected for metabolic testing. The serum concentrations of total protein (TP), bilirubin, cholesterol and betahydroxybutyrate were measured as well as the activities of Glutamate‐Dehydrogenase (GLDH) and Aspartate‐Aminotransferase. MAP‐positive cows were characterised by a decreased mean TP (66.5 g/l) compared to the MAP‐negative controls (73.2 g/l). Mean log10 GLDH activities tended to be higher in MAP‐positive than MAP‐negative cows. Concerning TP, there was a significant interaction between MAP status and farm. Within four farms, the difference between MAP‐positive and MAP‐negative animals differed significantly, while in the other farms this difference was not significant. It is concluded that a decreased TP and an increased GLDH indicate alterations in protein metabolism. These findings suggest an enhanced liver cell turnover in MAP‐positive cows. The results contribute to an understanding of the metabolic alterations in MAP‐positive dairy cows.