bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ex Vivo Mechanical Tests and Multiscale Computational Modeling Highlight the Importance of Intramural Shear Stress in Ascending Thoracic Aortic Aneurysms
Authors: Korenczuk Christopher E. , Dhume Rohit Y. , Liao Kenneth K. , Barocas Victor H. 
Published: October 2019

Abstract
Ascending thoracic aortic aneurysms (ATAAs) are anatomically complex in terms of architecture and geometry, and both complexities contribute to unpredictability of ATAA dissection and rupture in vivo. The goal of this work was to examine the mechanism of ATAA failure using a combination of detailed mechanical tests on human tissue and a multiscale computational model. We used (1) multiple, geometrically diverse, mechanical tests to characterize tissue properties; (2) a multiscale computational model to translate those results into a broadly usable form; and (3) a model-based computer simulation of the response of an ATAA to the stresses generated by the blood pressure. Mechanical tests were performed in uniaxial extension, biaxial extension, shear lap, and peel geometries. ATAA tissue was strongest in circumferential extension and weakest in shear, presumably because of the collagen and elastin in the arterial lamellae. A multiscale, fiber-based model using different fiber properties for collagen, elastin, and interlamellar connections was specified to match all of the experimental data with one parameter set. Finally, this model was used to simulate ATAA inflation using a realistic geometry. The predicted tissue failure occurred in regions of high stress, as expected; initial failure events involved almost entirely interlamellar connections, consistent with arterial dissection—the elastic lamellae remain intact, but the connections between them fail. The failure of the interlamellar connections, paired with the weakness of the tissue under shear loading, is suggestive that shear stress within the tissue may contribute to ATAA dissection.
Educational impact of a pilot paediatric simulation-based training course in Botswana
Authors: Glomb Nicolaus W , Shah Manish I , Kosoko Adeola A , Doughty Cara B , Galapi Cafen , Laba Bushe , Rus Marideth C 
Published: October 2019

BackgroundAs emergency medical services (EMS) systems develop globally in resource-limited settings, equipping providers with paediatric training is essential. Low-fidelity simulation-based training is an effective modality for training healthcare workers, though limited data exist on the impact of such training programmes. The objective of this study was to evaluate the paediatric portion of a simulation-based curriculum for prehospital providers in Botswana.MethodsThis was a prospective cohort study of EMS providers from more populated regions of Botswana, who attended a 2-day training that included didactic lectures, hands-on skills stations and low-fidelity simulation training. We collected data on participant self-efficacy with paediatric knowledge and skills and performance on both written and simulation-based tests. Self-efficacy and test data were analysed, and qualitative course feedback was summarised.ResultsThirty-one EMS providers participated in the training. Median self-efficacy levels increased for 13/15 (87%) variables queried. The most notable improvements were observed in airway management, newborn resuscitation and weight estimation. Mean written test scores increased by 10.6%, while mean simulation test scores increased by 21.5% (p<0.0001). One hundred per cent of the participants rated the course as extremely useful or very useful.Discussion/ConclusionWe have demonstrated that a low-fidelity simulation-based training course based on a rigorous needs assessment may enhance short-term paediatric knowledge and skills for providers in a developing EMS system in a limited-resource setting. Future studies should focus on studying larger groups of learners in similar settings, especially with respect to the impact of educational programmes like these on real-world patient outcomes.
Berry–Esséen bound for the parameter estimation of fractional Ornstein–Uhlenbeck processes
Authors: Chen Yong , Kuang Nenghui , Li Ying 
Published: October 2019

For an Ornstein–Uhlenbeck process driven by fractional Brownian motion with Hurst index [Formula: see text], we show the Berry–Esséen bound of the least squares estimator of the drift parameter based on the continuous-time observation. We use an approach based on Malliavin calculus given by Kim and Park [Optimal Berry–Esséen bound for statistical estimations and its application to SPDE, J. Multivariate Anal. 155 (2017) 284–304].
Topographic Mechanics and Applications of Liquid Crystalline Solids
Authors: Warner Mark 
Published: October 2019

Liquid crystal elastomers and glasses suffer huge length changes on heating, illumination, exposure to humidity, etc. A challenge is to program these changes to give a complex mechanical response for micromachines and soft robotics. Also desirable can be strong response, where bend is avoided in favor of stretch and compression, even in the slender shells that are our subject. A new mechanics paradigm arises from such materials—spatially programmed anisotropy allows a spatially varying metric to develop upon stimulation, with evolving Gaussian curvature, topography changes, and superstrong actuation. We call this metric mechanics or topographical mechanics. Thus programmed, liquid crystalline solids meet the above aims. A frontier is the complete programming and control of topography, driving both Gaussian and mean curvature evolution. That, and smart shells, which sense and self-regulate, and exotic new realizations of anisotropic responsive structures, are our concluding themes.
Comparison of murine steatohepatitis models identifies a dietary intervention with robust fibrosis, ductular reaction, and rapid progression to cirrhosis and cancer
Authors: Wei Guangyan , An Ping , Vaid Kahini A. , Nasser Imad , Huang Pinzhu , Tan Li , Zhao Shuangshuang , Schuppan Detlef , Popov Yury V. 
Published: October 2019

Progressive fibrosis, functional liver failure, and cancer are the central liver-related outcomes of nonalcoholic steatohepatitis (NASH) but notoriously difficult to achieve in mouse models. We performed a direct, quantitative comparison of hepatic fibrosis progression in well-defined methionine- and choline-deficient (MCD) and choline-deficient, amino-acid defined (CDAA) diets with increasing fat content (10–60% by calories) in C57Bl/6J and BALB/cAnNCrl mice. In C57Bl/6J mice, MCD feeding resulted in moderate fibrosis at week 8 (up to twofold increase in total hepatic collagen content) and progressive weight loss irrespective of dietary fat. In contrast, CDAA-fed mice did not lose weight and developed progressive fibrosis starting from week 4. High dietary fat in the CDAA diet model induced the lipid metabolism genes for sterol regulatory element-binding protein and stearoyl-CoA desaturase-2 and increased ductular reaction and fibrosis in a dose-dependent manner. Longitudinal analysis of CDAA with 60% fat (HF-CDAA) feeding revealed pronounced ductular reaction and perisinusoidal bridging fibrosis, with a sevenfold increase of hepatic collagen at week 12, which showed limited spontaneous reversibility. At 24 wk, HF-CDAA mice developed signs of cirrhosis with pan-lobular “chicken wire” fibrosis, 10-fold hydroxyproline increase, regenerative nodules, portal hypertension and elevated serum bilirubin and ammonia levels; 80% of mice (8/10) developed multiple glypican-3- and/or glutamine synthetase-positive hepatocellular carcinomas (HCC). High-fat (60%) supplementation of MCD in C57Bl/6J or feeding the HF-CDAA diet fibrosis-prone BALB/cAnNCrl strain failed to result in increased fibrosis. In conclusion, HF-CDAA feeding in C57Bl/6J mice was identified as an optimal model of steatohepatitis with robust fibrosis and ductular proliferations that progress to cirrhosis and HCC within 24 wk. This robust model will aid the testing of interventions and drugs for severe NASH. NEW & NOTEWORTHY Via quantitative comparison of several dietary models, we report HF-CDAA feeding in C57Bl/6 mice as an excellent model recapitulating several key aspects of fibrotic NASH: 1) robust, poorly reversible liver fibrosis, 2) prominent ductular reaction, and 3) progression to cirrhosis, portal hypertension, and liver cancer within 24 wk. High fat dose-dependently activates SREBP2/SCD2 genes and drives liver fibrosis in e HF-CDAA model. These features qualify the model as a robust and practical tool to study mechanisms and novel treatments addressing severe human NASH.
Deep Learning Based on Standard H&E Images of Primary Melanoma Tumors Identifies Patients at Risk for Visceral Recurrence and Death
Authors: Kulkarni Prathamesh M. , Robinson Eric J. , Sarin Pradhan Jaya , Gartrell-Corrado Robyn D. , Rohr Bethany R. , Trager Megan H. , Geskin Larisa J. , Kluger Harriet M. , Wong Pok Fai , Acs Balazs , Rizk Emanuelle M. , Yang Chen , Mondal Manas , Moore Michael R. , Osman Iman , Phelps Robert , Horst Basil A. , Chen Zhe S. , Ferringer Tammie , Rimm David L. , Wang Jing , Saenger Yvonne M. 
Published: October 2019

Abstract

Purpose:
Biomarkers for disease-specific survival (DSS) in early-stage melanoma are needed to select patients for adjuvant immunotherapy and accelerate clinical trial design. We present a pathology-based computational method using a deep neural network architecture for DSS prediction.

Experimental Design:
The model was trained on 108 patients from four institutions and tested on 104 patients from Yale School of Medicine (YSM, New Haven, CT). A receiver operating characteristic (ROC) curve was generated on the basis of vote aggregation of individual image sequences, an optimized cutoff was selected, and the computational model was tested on a third independent population of 51 patients from Geisinger Health Systems (GHS).

Results:
Area under the curve (AUC) in the YSM patients was 0.905 (P &lt; 0.0001). AUC in the GHS patients was 0.880 (P &lt; 0.0001). Using the cutoff selected in the YSM cohort, the computational model predicted DSS in the GHS cohort based on Kaplan–Meier (KM) analysis (P &lt; 0.0001).

Conclusions:
The novel method presented is applicable to digital images, obviating the need for sample shipment and manipulation and representing a practical advance over current genetic and IHC-based methods.
Cryoballoon or Radiofrequency Ablation for Atrial Fibrillation Assessed by Continuous Monitoring
Authors: Andrade Jason G. , Champagne Jean , Dubuc Marc , Deyell Marc W. , Verma Atul , Macle Laurent , Leong-Sit Peter , Novak Paul , Badra-Verdu Mariano , Sapp John , Mangat Iqwal , Khoo Clarence , Steinberg Christian , Bennett Matthew T. , Tang Anthony S.L. , Khairy Paul ,   For the CIRCA-DOSE Study Investigators, Parkash Ratika , Guerra Peter , Dyrda Katia , Rivard Lena , Racine Normand , Sterns Lawrence , Leather Rick , Seifer Colette , Jolly Umjeet , Raymond Jean-Marc , Roux Jean-Francois , Nault Isabelle , Sarrazin Jean-Francois , Ramanathan Krishnan , Cheung Christopher , Fordyce Christopher , McKinney Jimmy , Luong Christina , Rizkallah Jacques , Angaran Paul , Ha Andrew , Glover Benedict , Skanes Allan , Gula Lorne 
Published: October 2019

Background:
Advanced generation ablation technologies have been developed to achieve more effective pulmonary vein isolation (PVI) and minimize arrhythmia recurrence after atrial fibrillation (AF) ablation.

Methods:
We randomly assigned 346 patients with drug-refractory paroxysmal AF to contact force–guided radiofrequency ablation (CF-RF; n=115), 4-minute cryoballoon ablation (Cryo-4; n=115), or 2-minute cryoballoon ablation (Cryo-2; n=116). Follow-up was 12 months. The primary outcome was time to first documented recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia) between days 91 and 365 after ablation or a repeat ablation procedure at any time. Secondary end points included freedom from symptomatic arrhythmia and AF burden. All patients received an implantable loop recorder.

Results:

One-year freedom from atrial tachyarrhythmia defined by continuous rhythm monitoring was 53.9%, 52.2%, and 51.7% with CF-RF, Cryo-4, and Cryo-2, respectively (
P
=0.87). One-year freedom from symptomatic atrial tachyarrhythmia defined by continuous rhythm monitoring was 79.1%, 78.2%, and 73.3% with CF-RF, Cryo-4, and Cryo-2, respectively (
P
=0.26). Compared with the monitoring period before ablation, AF burden was reduced by a median of 99.3% (interquartile range, 67.8%–100.0%) with CF-RF, 99.9% (interquartile range, 65.3%–100.0%) with Cryo-4, and 98.4% (interquartile range, 56.2%–100.0%) with Cryo-2 (
P
=0.36). Serious adverse events occurred in 3 patients (2.6%) in the CF-RF group, 6 patients (5.3%) in the Cryo-4 group, and 7 patients (6.0%) in the Cryo-2 group, with no significant difference between groups (
P
=0.24). The CF-RF group had a significantly longer procedure duration but significantly shorter fluoroscopy exposure (
P
<0.001 vs cryoballoon groups).

Conclusions:
In this multicenter, randomized, single-blinded trial, CF-RF and 2 different regimens of cryoballoon ablation resulted in no difference in 1-year efficacy, which was 53% by time to first recurrence but >98% burden reduction as assessed by continuous cardiac rhythm monitoring.

Clinical Trial Registration:

URL:
https://www.clinicaltrials.gov
. Unique identifier: NCT01913522.
Black Carbon Increases Frequency of Extreme ENSO Events
Authors: Lou Sijia , Yang Yang , Wang Hailong , Lu Jian , Smith Steven J. , Liu Fukai , Rasch Philip J. 
Published: October 2019

ABSTRACTEl Niño–Southern Oscillation (ENSO) is the leading mode of Earth’s climate variability at interannual time scales with profound ecological and societal impacts, and it is projected to intensify in many climate models as the climate warms under the forcing of increasing CO2 concentration. Since the preindustrial era, black carbon (BC) emissions have substantially increased in the Northern Hemisphere. But how BC aerosol forcing may influence the occurrence of the extreme ENSO events has rarely been investigated. In this study, using simulations of a global climate model, we show that increases in BC emissions from both the midlatitudes and Arctic weaken latitudinal temperature gradients and northward heat transport, decrease tropical energy divergence, and increase sea surface temperature over the tropical oceans, with a surprising consequential increase in the frequency of extreme ENSO events. A corollary of this study is that reducing BC emissions might serve to mitigate the possible increasing frequency of extreme ENSO events under greenhouse warming, if the modeling result can be translated into the climate in reality.
IMERG V06: Changes to the Morphing Algorithm
Authors: Tan Jackson , Huffman George J. , Bolvin David T. , Nelkin Eric J. 
Published: October 2019

AbstractAs the U.S. Science Team’s globally gridded precipitation product from the NASA–JAXA Global Precipitation Measurement (GPM) mission, the Integrated Multi-Satellite Retrievals for GPM (IMERG) estimates the surface precipitation rates at 0.1° every half hour using spaceborne sensors for various scientific and societal applications. One key component of IMERG is the morphing algorithm, which uses motion vectors to perform quasi-Lagrangian interpolation to fill in gaps in the passive microwave precipitation field using motion vectors. Up to IMERG V05, the motion vectors were derived from the large-scale motions of infrared observations of cloud tops. This study details the changes introduced in IMERG V06 to derive motion vectors from large-scale motions of selected atmospheric variables in numerical models, which allow IMERG estimates to be extended from the 60°N–60°S latitude band to the entire globe. Evaluation against both instantaneous passive microwave retrievals and ground measurements demonstrates the general improvement in the precipitation field of the new approach. Most of the model variables tested exhibited similar performance, but total precipitable water vapor was chosen as the source of the motion vectors for IMERG V06 due to its competitive performance and global completeness. Continuing assessments will provide further insights into possible refinements of this revised morphing scheme in future versions of IMERG.
Effects of Under-Resolved Convective Dynamics on the Evolution of a Squall Line
Authors: Varble Adam , Morrison Hugh , Zipser Edward 
Published: October 2019

Abstract
Simulations of a squall line observed on 20 May 2011 during the Midlatitude Continental Convective Clouds Experiment (MC3E) using 750- and 250-m horizontal grid spacing are performed. The higher-resolution simulation has less upshear-tilted deep convection and a more elevated rear inflow jet than the coarser-resolution simulation in better agreement with radar observations. A stronger cold pool eventually develops in the 250-m run; however, the more elevated rear inflow counteracts the cold pool circulation to produce more upright convective cores relative to the 750-m run. The differing structure in the 750-m run produces excessive midlevel front-to-rear detrainment, reinforcing excessive latent cooling and rear inflow descent at the rear of the stratiform region in a positive feedback. The contrasting mesoscale circulations are connected to early stage deep convective draft differences in the two simulations. Convective downdraft condensate mass, latent cooling, and downward motion all increase with downdraft area similarly in both simulations. However, the 750-m run has a relatively greater number of wide and fewer narrow downdrafts than the 250-m run averaged to the same 750-m grid, a consequence of downdrafts being under-resolved in the 750-m run. Under-resolved downdrafts in the 750-m run are associated with under-resolved updrafts and transport mid–upper-level zonal momentum downward to low levels too efficiently in the early stage deep convection. These results imply that under-resolved convective drafts in simulations may vertically transport air too efficiently and too far vertically, potentially biasing buoyancy and momentum distributions that impact mesoscale convective system evolution.
Improving Tracheostomy Care in Resource-Limited Settings
Authors: Sandler Mykayla L. , Ayele Nohamin , Ncogoza Isaie , Blanchette Susan , Munhall Daphne S. , Marques Brittanie , Nuss Roger C. 
Published: October 2019

Objectives: Tracheostomy care in leading pediatric hospitals is both multidisciplinary and comprehensive, including generalized care protocols and thorough family training programs. This level of care is more difficult in resource-limited settings lacking developed healthcare infrastructure and tracheostomy education among nursing and resident staff. The objective of this study was to improve pediatric tracheostomy care in resource-limited settings. Methods: In collaboration with a team of otolaryngologists, respiratory therapists, tracheostomy nurses, medical illustrators, and global health educators, image-based tracheostomy education materials and low-cost tracheostomy care kits were developed for use in resource-limited settings. In addition, a pilot study was conducted, implementing the image-based tracheostomy pamphlet, manual suctioning device and low-cost ambulatory supply kit (“Go-Bags”), within a low-fidelity simulated training course for nurses and residents in Kigali, Rwanda. Results: An image-based language and literacy-independent tracheostomy care manual was created and published on OPENPediatrics, an open-access online database of clinician-reviewed learning content. Participants of the training program pilot study reported the course to be of high educational and practical value, and described improved confidence in their ability to perform tracheostomy care procedures. Conclusions: Outpatient tracheostomy care may be improved upon by implementing image-based tracheostomy care manuals, locally-sourced tracheostomy care kits, and tailored educational material into a low-fidelity simulated tracheostomy care course. These materials were effective in improving technical skills and confidence among nurses and residents. These tools are expected to improve knowledge and skills with outpatient tracheostomy care, and ultimately, to reduce tracheostomy-related complications.
Preoperative Maxillary Sinus Imaging and the Outcome of Sinus Floor Augmentation and Dental Implants in Asymptomatic Patients
Authors: Ritter Amit , Rozendorn Noa , Avishai Gal , Rosenfeld Eli , Koren Ilan , Soudry Ethan 
Published: October 2019

Objectives: Preoperative maxillary sinus imaging findings have been suggested to be associated with complications and outcomes of sinus lift and dental implant procedures; nonetheless the evidence is controversial. The aim of this study was to examine the association between preoperative maxillary sinus imaging findings and outcomes of sinus lift and dental implant procedures in asymptomatic patients. Methods: We included all patients who underwent maxillary sinus lift and dental implant procedures between 2014 and 2017. Maxillary sinus imaging findings were extracted from pre-procedural dental computed tomography scans, and outcomes of the procedures were assessed. Results: A total of 145 procedures were included. No sinonasal symptoms were reported preoperatively. In 46% of cases maxillary sinus imaging was abnormal. The most common imaging finding was peripheral mucosal thickening (38%). Sinus floor cyst/polyp was identified in 13% of the cases, of which 47% occupied more than 50% of the sinus volume. Partial or complete opacification of the maxillary sinus was documented in 3% of cases. The sinus ostium and ostiomeatal complex were obstructed in 7% and 1%, respectively. Mucosal perforation was documented in 22% of cases and was inversely related to mucosal thickening ( P = 0.011). Other minor post-operative complications did not correlate with radiological findings. Post-surgical sinusitis was not observed in any of the patients regardless of pre-surgical imaging findings. Conclusions: Incidental maxillary sinus imaging findings such as mucosal swelling, cysts or polyps, regardless of their severity or size, and maxillary ostial obstruction may not need to be addressed prior to sinus augmentation and dental implant procedures in asymptomatic patients. Patients with complete sinus opacification should be referred to an otolaryngologist prior to surgery. Further controlled trials, in larger cohorts, are needed to corroborate our findings.