bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sex Differences in Hemodynamic and Microvascular Mechanisms of Myocardial Ischemia Induced by Mental Stress
Authors: Sullivan Samaah , Hammadah Muhammad , Al Mheid Ibhar , Wilmot Kobina , Ramadan Ronnie , Alkhoder Ayman , Isakadze Nino , Shah Amit , Levantsevych Oleksiy , Pimple Pratik M. , Kutner Michael , Ward Laura , Garcia Ernest V. , Nye Jonathon , Mehta Puja K. , Lewis Tené T. , Bremner J. Douglas , Raggi Paolo , Quyyumi Arshed A. , Vaccarino Viola 
Published: December 2017

Objective—
To investigate sex-specific vascular mechanisms for mental stress-induced myocardial ischemia (MSIMI).

Approach and Results—
Baseline data from a prospective cohort study of 678 patients with coronary artery disease underwent myocardial perfusion imaging before and during a public speaking stressor. The rate-pressure product response was calculated as the difference between the maximum value during the speech minus the minimum value during rest. Peripheral vasoconstriction by peripheral arterial tonometry was calculated as the ratio of pulse wave amplitude during the speech over the resting baseline; ratios <1 indicate a vasoconstrictive response. MSIMI was defined as percent of left ventricle that was ischemic and as a dichotomous variable. Men (but not women) with MSIMI had a higher rate-pressure product response than those without MSIMI (6500 versus 4800 mm Hg bpm), whereas women (but not men) with MSIMI had a significantly lower peripheral arterial tonometry ratio than those without MSIMI (0.5 versus 0.8). In adjusted linear regression, each 1000-U increase in rate-pressure product response was associated with 0.32% (95% confidence interval, 0.22–0.42) increase in inducible ischemia among men, whereas each 0.10-U decrease in peripheral arterial tonometry ratio was associated with 0.23% (95% confidence interval, 0.11–0.35) increase in inducible myocardial ischemia among women. Results were independent of conventional stress-induced myocardial ischemia.

Conclusions—
Women and men have distinct cardiovascular reactivity mechanisms for MSIMI. For women, stress-induced peripheral vasoconstriction with mental stress, and not increased hemodynamic workload, is associated with MSIMI, whereas for men, it is the opposite. Future studies should examine these pathways on long-term outcomes.
Quantification of the Arrhythmogenic Effects of Spontaneous Atrial Extrasystole Using High-Resolution Epicardial Mapping
Authors: Teuwen Christophe P. , Kik Charles , van der Does Lisette J.M.E. , Lanters Eva A.H. , Knops Paul , Mouws Elisabeth M.J.P. , Bogers Ad J.J.C. , de Groot Natasja M.S. 
Published: December 2017

Background
Atrial extrasystoles (AES) can initiate atrial fibrillation. However, the impact of spontaneous AES on intra-atrial conduction is unknown. The aims of this study were to examine conduction disorders provoked by AES and to correlate these conduction differences with patient characteristics, mapping locations, and type of AES.

Methods and Results

High-resolution epicardial mapping (electrodes N=128 or N=192; interelectrode distance, 2 mm) of the entire atrial surface was performed in patients (N=164; 69.5% male; age 67.2±10.5 years) undergoing open-chest cardiac surgery. AES were classified as premature, aberrant, or prematurely aberrant. Conduction delay and conduction block were quantified during sinus rhythm and AES and subsequently compared. Median incidence of conduction delay and conduction block during sinus rhythm was 1.2% (interquartile, 0%−2.3%) and 0.4% (interquartile, 0%−2.1%). In comparison, the median incidence of conduction delay and conduction block during 339 AES was respectively 2.8% (interquartile, 1.3%−4.6%) and 2.2% (interquartile, 0.3%−5.1%) and differed between the types of AES (prematurely aberrant>aberrant>premature). The degree of prematurity was not associated with a higher incidence of conduction disorders (
P
>0.05). In contrast, a higher degree of aberrancy was associated with a higher incidence of conduction disorders; AES emerging as epicardial breakthrough provoked most conduction disorders (
P
≥0.002). AES caused most conduction disorders in patients with diabetes mellitus and left atrial dilatation (
P
<0.05).

Conclusions
Intraoperative high-resolution epicardial mapping showed that conduction disorders are mainly provoked by prematurely aberrant AES, particularly in patients with left atrial dilation and diabetes mellitus or emerging as epicardial breakthrough.
Prognostic Implications of Magnetic Resonance–Derived Quantification in Asymptomatic Patients With Organic Mitral Regurgitation
Authors: Penicka Martin , Vecera Jan , Mirica Daniela C. , Kotrc Martin , Kockova Radka , Van Camp Guy 
Published: December 2017

Background:
Magnetic resonance imaging (MRI) is an accurate method for the quantitative assessment of organic mitral regurgitation (OMR). The aim of the present study was to compare the discriminative power of MRI quantification and the recommended Doppler echocardiography (ECHO)–derived integrative approach to identify asymptomatic patients with OMR and adverse outcome.

Methods:
The study population consisted of 258 asymptomatic patients (63±14 years, 60% men) with preserved left ventricular ejection fraction (>60%) and chronic moderate and severe OMR (flail 25%, prolapse 75%) defined by using the ECHO-derived integrative approach. All patients underwent MRI to quantify regurgitant volume (RV) of OMR by subtracting the aortic forward flow volume from the total left ventricular stroke volume. Severe OMR was defined as RV≥60 mL.

Results:

Mean ECHO-derived RV was on average 17.1 mL larger than the MRI-derived RV (
P
<0.05). Concordant grading of OMR severity with both techniques was observed in 197 (76%) individuals with 62 (31%) patients having severe OMR (MRI SEV-ECHO SEV) and 135 (69%) patients having moderate OMR (MRI MOD-ECHO MOD). The remaining 61 (24%) individuals had discordant findings (MRI SEV-ECHO MOD or MRI MOD-ECHO SEV) between the 2 techniques. The majority of these differences in OMR classification were observed in patients with late systolic or multiple jets (both κ<0.2). Patients with eccentric jets showed moderate agreement (κ=0.53; 95% confidence interval, 0.41–0.64). In contrast, a very good agreement (κ=0.90; 95% confidence interval, 0.82–0.98) was observed in a combination of holosystolic, central, and single jet. During a median follow-up of 5.0 years (interquartile range, 3.5–6.0 years), 38 (15%) patients died and 106 (41%) either died or developed indication for mitral valve surgery. In separate Cox regression analyses, the MRI-derived left ventricular end-systolic volume index, RV, and OMR category (severe versus moderate), and the ECHO-derived OMR category were independent predictors of all-cause mortality (all
P
<0.05). The MRI-derived RV showed the largest area under the curve to predict mortality (0.72) or its combination with the development of indication for mitral valve surgery (0.83).

Conclusions:
The findings of the present study suggest that the MRI-derived assessment of OMR can better identify patients with severe OMR and adverse outcome than ECHO-derived integrative approach warranting close follow-up and perhaps, early mitral valve surgery.
Risk Factors of Sudden Cardiac Death in the Young
Authors: Jayaraman Reshmy , Reinier Kyndaron , Nair Sandeep , Aro Aapo L. , Uy-Evanado Audrey , Rusinaru Carmen , Stecker Eric C. , Gunson Karen , Jui Jonathan , Chugh Sumeet S. 
Published: December 2017

Background:
Prevention of sudden cardiac arrest (SCA) in the young remains a largely unsolved public health problem, and sports activity is an established trigger. Although the presence of standard cardiovascular risk factors in the young can link to future morbidity and mortality in adulthood, the potential contribution of these risk factors to SCA in the young has not been evaluated.

Methods:
We prospectively ascertained subjects who experienced SCA between the ages of 5 and 34 years in the Portland, Oregon, metropolitan area (2002–2015, catchment population ≈1 million). We assessed the circumstances, resuscitation outcomes, and clinical profile of subjects who had SCA by a detailed evaluation of emergency response records, lifetime clinical records, and autopsy examinations. We specifically evaluated the association of standard cardiovascular risk factors and SCA, and sports as a trigger for SCA in the young.

Results:

Of 3775 SCAs in all age groups, 186 (5%) occurred in the young (mean age 25.9±6.8, 67% male). In SCA in the young, overall prevalence of warning signs before SCA was low (29%), and 26 (14%) were associated with sports as a trigger. The remainder (n=160) occurred in other settings categorized as nonsports. Sports-related SCAs accounted for 39% of SCAs in patients aged ≤18, 13% of SCAs in patients aged 19 to 25, and 7% of SCAs in patients aged 25 to 34. Sports-related SCA cases were more likely to present with shockable rhythms, and survival from cardiac arrest was 2.5-fold higher in sports-related versus nonsports SCA (28% versus 11%;
P
=0.05). Overall, the most common SCA-related conditions were sudden arrhythmic death syndrome (31%), coronary artery disease (22%), and hypertrophic cardiomyopathy (14%). There was an unexpectedly high overall prevalence of established cardiovascular risk factors (obesity, diabetes mellitus, hypertension, hyperlipidemia, smoking) with ≥1 risk factors in 58% of SCA cases.

Conclusions:
Sports was a trigger of SCA in a minority of cases, and, in most patients, SCA occurred without warning symptoms. Standard cardiovascular risk factors were found in over half of patients, suggesting the potential role of public health approaches that screen for cardiovascular risk factors at earlier ages.
Helicity and Vorticity of Pulmonary Arterial Flow in Patients With Pulmonary Hypertension: Quantitative Analysis of Flow Formations
Authors: Schäfer Michal , Barker Alex J. , Kheyfets Vitaly , Stenmark Kurt R. , Crapo James , Yeager Michael E. , Truong Uyen , Buckner J. Kern , Fenster Brett E. , Hunter Kendall S. 
Published: December 2017

Background

Qualitative and quantitative flow hemodynamic indexes have been shown to reflect right ventricular (
RV
) afterload and function in pulmonary hypertension (
PH
). We aimed to quantify flow hemodynamic formations in pulmonary arteries using 4‐dimensional flow cardiac magnetic resonance imaging and the spatial velocity derivatives helicity and vorticity in a heterogeneous PH population.

Methods and Results

Patients with PH (n=35) and controls (n=10) underwent 4‐dimensional flow magnetic resonance imaging study for computation of helicity and vorticity in the main pulmonary artery (
MPA
), the right pulmonary artery, and the
RV
outflow tract. Helicity and vorticity were correlated with standard
RV
volumetric and functional indexes along with
MPA
stiffness assessed by measuring relative area change. Patients with
PH
had a significantly decreased helicity in the
MPA
(8 versus 32 m/s
2
;
P
<0.001), the right pulmonary artery (24 versus 50 m/s
2
;
P
<0.001), and the
RV
outflow tract–
MPA
unit (15 versus 42 m/s
2
;
P
<0.001). Vorticity was significantly decreased in patients with PH only in the right pulmonary artery (26 versus 45 1/s;
P
<0.001). Total helicity computed correlated with the cardiac magnetic resonance imaging–derived ventricular‐vascular coupling (−0.927;
P
<0.000), the
RV
ejection fraction (0.865;
P
<0.0001), cardiac output (0.581;
P
<0.0001), mean pulmonary arterial pressure (−0.581;
P
=0.0008), and relative area change measured at the
MPA
(0.789;
P
<0.0001).

Conclusions
The flow hemodynamic character in patients with PH assessed via quantitative analysis is considerably different when compared with healthy and normotensive controls. A strong association between helicity in pulmonary arteries and ventricular‐vascular coupling suggests a relationship between the mechanical and flow hemodynamic domains.
Can a Simple Dynamical System Describe the Interplay between Drag and Buoyancy in Terrain-Induced Canopy Flows?
Authors: De Roo Frederik , Banerjee Tirtha 
Published: December 2017

Abstract
Under nonneutral stratification and in the presence of topography, the dynamics of turbulent flow within a canopy is not yet completely understood. This has, among other consequences, serious implications for the measurement of surface–atmosphere exchange by means of eddy covariance: for example, the measurement of carbon dioxide fluxes is strongly influenced if drainage flows occur during night, when the flow within the canopy decouples from the flow aloft. An improved physical understanding of the behavior of scalars under canopy turbulence in complex terrain is urgently needed. In the present work, the authors investigate the dynamics of turbulent flow within sloped canopies, focusing on the slope wind and potential temperature. The authors concentrate on the presence of oscillatory behavior in the flow variables in terms of switching of flow regimes by conducting linear stability analysis. The authors revisit and correct the simplified theory that exists in the literature, which is based on the interplay between the drag force and the buoyancy. The authors find that the simplified description of this dynamical system cannot exhibit the observed richness of the dynamics. To augment the simplified dynamical system’s analysis, the authors make use of large-eddy simulation of a three-dimensional hill covered by a homogeneous forest and analyze the phase synchronization behavior of the buoyancy and drag forces in the momentum budget to explore the turbulent dynamics in more detail.
Impact of Winter Ural Blocking on Arctic Sea Ice: Short-Time Variability
Authors: Chen Xiaodan , Luo Dehai , Feldstein Steven B. , Lee Sukyoung 
Published: December 2017

AbstractUsing daily reanalysis data from 1979 to 2015, this paper examines the impact of winter Ural blocking (UB) on winter Arctic sea ice concentration (SIC) change over the Barents and Kara Seas (BKS). A case study of the sea ice variability in the BKS in the 2015/16 and 2016/17 winters is first presented to establish a link between the BKS sea ice variability and UB events. Then the UB events are classified into quasi-stationary (QUB), westward-shifting (WUB), and eastward-shifting (EUB) UB types. It is found that the frequency of the QUB events increases significantly during 1999–2015, whereas the WUB events show a decreasing frequency trend during 1979–2015.Moreover, it is shown that the variation of the BKS-SIC is related to downward infrared radiation (IR) and surface sensible and latent heat flux changes due to different zonal movements of the UB. Calculations show that the downward IR is the main driver of the BKS-SIC decline for QUB events, while the downward IR and surface sensible heat flux make comparable contributions to the BKS-SIC variation for WUB and EUB events. The SIC decline peak lags the QUB and EUB peaks by about 3 days, though QUB and EUB require lesser prior SIC. The QUB gives rise to the largest SIC decline likely because of its longer persistence, whereas the BKS-SIC decline is relatively weak for the EUB. The WUB is found to cause a SIC decline during its growth phase and an increase during its decay phase. Thus, the zonal movement of the UB has an important impact on the SIC variability in BKS.
Evaluation of Extratropical Cyclone Precipitation in the North Atlantic Basin: An Analysis of ERA-Interim, WRF, and Two CMIP5 Models
Authors: Booth James F. , Naud Catherine M. , Willison Jeff 
Published: December 2017

AbstractThe representation of extratropical cyclone (ETC) precipitation in general circulation models (GCMs) and the Weather Research and Forecasting (WRF) Model is analyzed. This work considers the link between ETC precipitation and dynamical strength and tests if parameterized convection affects this link for ETCs in the North Atlantic basin. Lagrangian cyclone tracks of ETCs in ERA-Interim (ERAI), GISS and GFDL CMIP5 models, and WRF with two horizontal resolutions are utilized in a compositing analysis. The 20-km-resolution WRF Model generates stronger ETCs based on surface wind speed and cyclone precipitation. The GCMs and ERAI generate similar composite means and distributions for cyclone precipitation rates, but GCMs generate weaker cyclone surface winds than ERAI. The amount of cyclone precipitation generated by the convection scheme differs significantly across the datasets, with the GISS model generating the most, followed by ERAI and then the GFDL model. The models and reanalysis generate relatively more parameterized convective precipitation when the total cyclone-averaged precipitation is smaller. This is partially due to the contribution of parameterized convective precipitation occurring more often late in the ETC’s life cycle. For reanalysis and models, precipitation increases with both cyclone moisture and surface wind speed, and this is true if the contribution from the parameterized convection scheme is larger or not. This work shows that these different models generate similar total ETC precipitation despite large differences in the parameterized convection, and these differences do not cause unexpected behavior in ETC precipitation sensitivity to cyclone moisture or surface wind speed.
Coordination of platelet agonist signaling during the hemostatic response in vivo
Authors: Shen Jian , Sampietro Sara , Wu Jie , Tang Juan , Gupta Shuchi , Matzko Chelsea N. , Tang Chaojun , Yu Ying , Brass Lawrence F. , Zhu Li , Stalker Timothy J. 
Published: December 2017

Key Points
Coordinated thromboxane A2 and ADP/P2Y12 signaling is required for platelet accumulation in the outer shell region of hemostatic plugs. Platelet activation within the hemostatic plug core region is predominantly mediated by thrombin.
Dynamic Risk Management of Commodity Operations: Model and Analysis
Authors: Devalkar Sripad K. , Anupindi Ravi , Sinha Amitabh 
Published: December 2017

Adverse commodity prices can cause significant negative cash flows and expose firms that deal in commodities to financial distress. In this paper we consider the dynamic risk management problem for a commodity processor operating in a partially complete market, facing both price uncertainty and significant financial distress costs. The firm procures an input commodity, processes it to produce an output commodity, and trades the output commodity in each period over a multiperiod horizon. The firm’s objective is to dynamically and jointly plan operational and financial hedging decisions to maximize the market-based value of cash flows under a time-consistent risk measure. We show that the optimal operational policy has the same price and horizon dependent threshold structure that obtains when markets are complete. We also characterize conditions under which a myopic policy is optimal. We present numerical studies to illustrate that (i) compared to using a myopic policy or a policy that neglects to model financial distress costs, the advantage of using the optimal policy is significant for firms that face moderate financial distress costs and have excess procurement capacity; (ii) more acute financial distress costs reduce the firm’s market-based value and throughput; and (iii) financial hedging provides considerable benefit by reducing the incidence of large negative cash flows. The online appendix is available at https://doi.org/10.1287/msom.2017.0647 .
Examining of the relationship between math anxiety and math achievement of elementary school students<p>İlkokul öğrencilerinin matematik kaygısı ile matematik başarıları arasındaki ilişkinin incelenmesi
Authors: Mutlu Yılmaz , Söylemez İhsan , Yasul Ali Fuad 
Published: December 2017

This study aims to investigate relation between math anxiety and mathmatical achievement of 3hd and 4th grade elementary school students. The participants of the study were constituted of totally 474 students, while 288 of those were attending 3hd grade, other 186 attending 4th grade. They were used math anxiety scale (13 items) developed by Mutlu & Söylemez (2017) for 3hd and 4th grades and math achievement tests for 3hd (16 items) and 4th (24 items) grades developed by Fidan (2013) as data gathering tools. They were also used pearson product-moment correlation, linear regression, t-test, oneway anova and two-step clustering methods to analyse data. The data concerning math anxiety and achievement were analysed through pearson product-moment correlation and linear regression. The relation level was found -547 between students’ math anxiety and math achievement. Besides, it was located that math anxiety explains 35% total varience of math achievement. With all that, it was used two-step clustering analyse method over math anxiety and achievement. There were found significant differences between participants’ math anxiety and math achievement scores.Extended English abstract is in the end of Full Text PDF (TURKISH) file.ÖzetBu çalışma, ilkokul 3. ve 4. sınıf öğrencilerinin matematik kaygısı ile matematik başarısı arasındaki ilişkiyi incelemeyi amaçlamaktadır. Çalışmanın katılımcılarının 288’i 3. sınıf, 186’sı 4. sınıf olmak üzere toplamda 474 öğrenciden oluşmaktadır. Çalışmada veri toplamak üzere ilkokul 3. ve 4. sınıflar için Mutlu ve Söylemez (2017) tarafından geliştirilmiş olan 13 maddelik bir kaygı ölçeği ile 3. sınıflar için 16 maddeden oluşan, 4. Sınıflar için ise 24 maddeden oluşan Fidan (2013) tarafından geliştirilen matematik başarı testleri kullanılmıştır. Verilerin analizinde Pearson Momentler Çarpımı Korelasyonu, doğrusal regresyon, t-testi ve iki adımlı kümeleme analizi yapılmıştır. Öğrencilerin matematik kaygısı ve matematik başarısı puanları arasında ilişki düzeyi -.547 olarak bulunmuştur. Ayrıca matematik kaygısının matematik başarısına ilişkin toplam varyansın %35’ini açıkladığı tespit edilmiştir. Bununla beraber matematik kaygısı ve matematik başarısı ilişkisini incelemek üzere iki adımlı kümeleme analizi yapılmıştır. Katılımcıların matematik kaygı ve matematik başarı puanları üzerinde yapılan kümeleleme analizi ile gruplar belirlenmiş, grupların matematik başarıları ve matematik kaygıları arasında anlamlı farklılıklar olduğu tespit edilmiştir.
A new ELISA for autoantibodies to steroid 21-hydroxylase
Authors: del Pilar Larosa Maria , Chen Shu , Steinmaus Nora , Macrae Hannah , Guo Liang , Masiero Stefano , Garelli Silvia , Costa Miriam Dalla , Bossowski Artur , Furmaniak Jadwiga , Betterle Corrado , Smith Bernard Rees 
Published: December 2017

Abstract

Background:
A new ELISA for autoantibodies to steroid 21-hydroxylase (21-OH Ab) is described.

Methods:
In the assay test sample autoantibodies form a bridge between 21-OH coated onto the plate well and liquid phase 21-OH-biotin. Bound 21-OH-biotin is detected by the addition of streptavidin peroxidase and colorogenic peroxidase substrate.

Results:
Of 100 samples from patients with autoimmune Addison’s disease, 86 (86%) were positive for 21-OH Ab ELISA whereas 84 (84%) were positive in an immunoprecipitation assay based on 125I-labeled 21-OH. Six (0.6%) of 928 healthy adult blood donors and 1 (2.0%) of 49 adult patients with type 1 diabetes mellitus (T1DM) were positive by ELISA. No samples from adult patients with Graves’ disease (GD; n=50), celiac disease (n=29), systemic lupus erythematosis (n=9) or rheumatoid arthritis (n=20) were positive by ELISA. However, 2/51 (3.9%) children with GD, 3/69 (4.3%) children with Hashimoto’s thyroiditis (HT) and 3/119 (2.5%) children with T1DM alone or associated with autoimmune thyroid disorders were ELISA positive.

Conclusions:
The new assay should be useful for screening patients known to be at increased risk of developing clinical autoimmune Addison’s disease, in particular children with HT, GD and/or T1DM.