bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melt Electrospinning Polyethylene Fibers in Inert Atmosphere
Authors: Morikawa Kai , Vashisth Aniruddh , Bansala Taruna , Verma Pawan , Green Micah J. , Naraghi Mohammad 
Published: September 2020

AbstractElectrospinning is commonly used for fabrication of polymer fibers. Melt electrospinning, instead of the commonly used solution electrospinning, offers many advantages in generating polymer fibers without using solvents. However, polymer melts have high viscosity which poses major limitations in producing low diameter fibers. Here, melt electrospinning is investigated at elevated temperatures in inert atmosphere to reduce fiber diameters while suppressing thermal degradation. Two types of spinneret configurations, syringe and wire, with two distinct outcomes are studied. In syringe‐based electrospinning, increasing the nozzle temperature from 300 to 360 °C in nitrogen reduced fiber diameter significantly from 33 ± 5 to 10 ± 4 µm. Electrospinning in nitrogen leads to formation of fibers even at a high nozzle temperature of 360 °C, while this temperature leads to thermal degradation when spinning in air. In contrast, increasing the temperature of wire electrospinning setup do not lead to a noticeable reduction in diameter. This is attributed to the viscosity‐dependent flow rate in this method. Increasing the temperature leads to increased flow rates, promoting the formation of thicker fibers, while the increased stretchability promotes the formation of thinner fibers. The results clearly demonstrate advantages of developing polymer microfibers in inert atmosphere to avoid thermal degradation with a temperature‐independent flow control.
Nanomechanical Properties of a Supramolecular Helix Stabilized by Non‐Covalent Interactions
Authors: Wang Huijie , Shen Bowen , Song Yu , Lee Myongsoo , Zhang Wenke 
Published: September 2020

AbstractSupramolecular helices have unique properties and many potential applications, such as chiral separation and asymmetric catalysis. Mechanical property (stability) of the supramolecular helix plays important roles in their functions. Due to the limitation of detection method, it is quite challenging to investigate nanomechanical properties of individual supramolecular helices stabilized by pure supramolecular interactions. Here atomic force microscopy (AFM)‐based single molecule force spectroscopy (SMFS) is used to study the nanomechanical properties of a thermal‐responsive supramolecular helix. The unwinding force plateau is observed in the force‐extension curve, and the rupture force of the helix is dependent on the loading rate. In addition, the force‐induced unwinding process is reversible and there is almost no energy dissipation in the process. Furthermore, the result of thermal shape‐fluctuation analysis shows that the persistence length of the supramolecular helix is about 222 nm, which is much larger than helical structure formed by double‐stranded DNA (dsDNA). However, because of its unique backbone structure, the supramolecular helix exhibits higher dynamic flexibility during force‐induced deformation, since the persistence length determined from the stretching experiment is much smaller (1.1 nm).
Analysis of Heterozygous PRKN Variants and Copy‐Number Variations in Parkinson's Disease
Authors: Yu Eric , Rudakou Uladzislau , Krohn Lynne , Mufti Kheireddin , Ruskey Jennifer A. , Asayesh Farnaz , Estiar Mehrdad A. , Spiegelman Dan , Surface Matthew , Fahn Stanley , Waters Cheryl H. , Greenbaum Lior , Espay Alberto J. , Dauvilliers Yves , Dupré Nicolas , Rouleau Guy A. , Hassin‐Baer Sharon , Fon Edward A. , Alcalay Roy N. , Gan‐Or Ziv 
Published: September 2020

ABSTRACTBackgroundBiallelic PRKN mutation carriers with Parkinson's disease (PD) typically have an earlier disease onset, slow disease progression, and, often, different neuropathology compared to sporadic PD patients. However, the role of heterozygous PRKN variants in the risk of PD is controversial.ObjectivesOur aim was to examine the association between heterozygous PRKN variants, including single‐nucleotide variants and copy‐number variations (CNVs), and PD.MethodsWe fully sequenced PRKN in 2809 PD patients and 3629 healthy controls, including 1965 late‐onset (63.97 ± 7.79 years, 63% men) and 553 early‐onset PD patients (43.33 ± 6.59 years, 68% men). PRKN was sequenced using targeted next‐generation sequencing with molecular inversion probes. CNVs were identified using a combination of multiplex ligation‐dependent probe amplification and ExomeDepth. To examine whether rare heterozygous single‐nucleotide variants and CNVs in PRKN are associated with PD risk and onset, we used optimized sequence kernel association tests and regression models.ResultsWe did not find any associations between all types of PRKN variants and risk of PD. Pathogenic and likely‐pathogenic heterozygous single‐nucleotide variants and CNVs were less common among PD patients (1.52%) than among controls (1.8%, false discovery rate‐corrected P = 0.55). No associations with age at onset and in stratified analyses were found.ConclusionsHeterozygous single‐nucleotide variants and CNVs in PRKN are not associated with PD. Molecular inversion probes allow for rapid and cost‐effective detection of all types of PRKN variants, which may be useful for pretrial screening and for clinical and basic science studies targeting specifically PRKN patients. © 2020 International Parkinson and Movement Disorder Society
Frequency agile multiple‐input‐multiple‐output antenna design for 5G dynamic spectrum sharing in cognitive radio networks
Authors: Hussain Rifaqat , Khan Muhammad U. , Iqbal Naveed , AlMajali Eqab , Alja'Afreh Saqer S. , Johar Umar , Shamim Atif , Sharawi Mohammad S. 
Published: September 2020

AbstractIn this work, 2‐element slot‐based frequency reconfigurable (FR) multiple‐input‐multiple‐output (MIMO) antenna design antenna with a very wide‐sweep is proposed for dynamic spectrum sharing (DSS) in 5G technologies. FR is achieved using varactor diode with frequency tuning range from 1655 to 2605 MHz. The design is a low profile with planar structure having a single element footprint of 19.5 × 20 mm2. The two slot antenna elements of the MIMO configuration are etched out from a ground (GND) plane of dimensions of 60 × 120 mm2. The proposed antenna is narrow‐band and hence it is suitable for RF front‐end in the 5G‐enabled DSS in cognitive radio (CR) applications.
Toward improved 3D carotid artery imaging with Adaptive CaRdiac cOne BEAm computed Tomography (ACROBEAT)
Authors: Reynolds Tess , Dillon Owen , Prinable Joseph , Whelan Brendan , Keall Paul J. , O’Brien Ricky T. 
Published: September 2020

PurposeInterventional treatments of aneurysms in the carotid artery are increasingly being supplemented with three‐dimensional (3D) x‐ray imaging. The 3D imaging provides additional information on device sizing and stent malapposition during the procedure. Standard 3D x‐ray image acquisition is a one‐size fits all model, exposing patients to additional radiation and results in images that may have cardiac‐induced motion blur around the artery. Here, we investigate the potential of a novel dynamic imaging technique Adaptive CaRdiac cOne BEAm computed Tomography (ACROBEAT) to personalize image acquisition by adapting the gantry velocity and projection rate in real‐time to changes in the patient’s electrocardiogram (ECG) trace.MethodsWe compared the total number of projections acquired, estimated carotid artery widths and image quality between ACROBEAT and conventional (single rotation fixed gantry velocity and acquisition rate, no ECG‐gating) scans in a simulation study and a proof‐of‐concept physical phantom experimental study. The simulation study dataset consisted of an XCAT digital software phantom programmed with five patient‐measured ECG traces and artery motion curves. The ECG traces had average heart rates of 56, 64, 76, 86, and 100 bpm. To validate the concept experimentally, we designed and manufactured the physical phantom from an 8‐mm diameter silicon rubber tubing cast into Phytagel. An artery motion curve and the ECG trace with an average heart rate of 56 bpm was passed through the phantom. To implement ACROBEAT on the Siemens ARTIS pheno angiography system for the proof‐of‐concept experimental study, the Siemens Test Automation Control System was used. The total number of projections acquired and estimated carotid artery widths were compared between the ACROBEAT and conventional scans. As the ground truth was available for the simulation studies, the image quality metrics of Root Mean Square Error (RMSE) and Structural Similarity Index (SSIM) were also utilized to assess image quality.ResultsIn the simulation study, on average, ACROBEAT reduced the number of projections acquired by 63%, reduced carotid width estimation error by 65%, reduced RMSE by 11% and improved SSIM by 27% compared to conventional scans. In the proof‐of‐concept experimental study, ACROBEAT enabled a 60% reduction in the number of projections acquired and reduced carotid width estimation error by 69% compared to a conventional scan.ConclusionA simulation and proof‐of‐concept experimental study was completed applying a novel dynamic imaging protocol, ACROBEAT, to imaging the carotid artery. The ACROBEAT results showed significantly improved image quality with fewer projections, offering potential applications to intracranial interventional procedures negatively affected by cardiac motion.
Technical Note: Automatic segmentation of CT images for ventral body composition analysis
Authors: Fu Yabo , Ippolito Joseph E. , Ludwig Daniel R. , Nizamuddin Rehan , Li Harold H. , Yang Deshan 
Published: September 2020

PurposeBody composition is known to be associated with many diseases including diabetes, cancers, and cardiovascular diseases. In this paper, we developed a fully automatic body tissue decomposition procedure to segment three major compartments that are related to body composition analysis — subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and muscle. Three additional compartments — the ventral cavity, lung, and bones — were also segmented during the segmentation process to assist segmentation of the major compartments.MethodsA convolutional neural network (CNN) model with densely connected layers was developed to perform ventral cavity segmentation. An image processing workflow was developed to segment the ventral cavity in any patient’s computed tomography (CT) using the CNN model, then further segment the body tissue into multiple compartments using hysteresis thresholding followed by morphological operations. It is important to segment ventral cavity firstly to allow accurate separation of compartments with similar Hounsfield unit (HU) inside and outside the ventral cavity.ResultsThe ventral cavity segmentation CNN model was trained and tested with manually labeled ventral cavities in 60 CTs. Dice scores (mean ± standard deviation) for ventral cavity segmentation were 0.966 ± 0.012. Tested on CT datasets with intravenous (IV) and oral contrast, the Dice scores were 0.96 ± 0.02, 0.94 ± 0.06, 0.96 ± 0.04, 0.95 ± 0.04, and 0.99 ± 0.01 for bone, VAT, SAT, muscle, and lung, respectively. The respective Dice scores were 0.97 ± 0.02, 0.94 ± 0.07, 0.93 ± 0.06, 0.91 ± 0.04, and 0.99 ± 0.01 for non‐contrast CT datasets.ConclusionA body tissue decomposition procedure was developed to automatically segment multiple compartments of the ventral body. The proposed method enables fully automated quantification of three‐dimensional (3D) ventral body composition metrics from CT images.
Water calorimetry in MR‐linac: Direct measurement of absorbed dose and determination of chamber
Authors: D'Souza Mark , Nusrat Humza , Iakovenko Viktor , Keller Brian , Sahgal Arjun , Renaud James , Sarfehnia Arman 
Published: September 2020

PurposeTo use a portable 4°C cooled MR‐compatible water calorimeter to measure absorbed dose in a magnetic resonance‐guided radiation therapy (MRgRT) system. Furthermore, to use the calorimetric dose results and direct cross‐calibration to experimentally measure the combined beam quality and magnetic field correction factor () of a clinically used reference‐class ionization chamber placed under the same radiation field.MethodsAn Elekta Unity MR‐linac (7 MV FFF, B = 1.5 T) was used in this study. Measurements were taken using the in‐house designed and built water calorimeter. Following preparation and cooling of the system, the MR‐compatible calorimeter was positioned using a combination of MR and EPID imaging and the dose to water was measured by monitoring the radiation‐induced temperature change. Immediately after the calorimetric measurements, an A1SL ionization chamber was placed inside the calorimeter for direct cross‐calibration. The results allowed for a direct and absolute experimental measurement of for this chamber and comparison against existing Monte Carlo values.ResultsThe calorimeter was successfully positioned using imaging in under an hour. The 1‐hour setup time is from the time the calorimeter leaves storage to the first calorimetric measurement. Absorbed dose was successfully measured with a relative combined standard uncertainty of 0.71 % (k = 1). Through a cross‐calibration, the for an Exradin A1SL ionization chamber, set up perpendicular to the incident photon beam and opposite to the direction of the Lorentz force, was directly determined in water in absolute terms to be 0.977 ± 0.010. The currently published results, obtained via Monte Carlo calculations, agree with experimental measurements in this work within combined uncertainties.ConclusionsA novel design of an MR‐compatible water calorimeter was successfully used to measure absorbed dose in an MR‐linac and determine an experimental value of for a clinically used ionization chamber.
Evaluation of differences and dosimetric influences of beam models using golden and multi‐institutional measured beam datasets in radiation treatment planning systems
Authors: Tani Kensuke , Wakita Akihisa , Tohyama Naoki , Fujita Yukio , Kito Satoshi , Miyasaka Ryohei , Mizuno Norifumi , Uehara Ryuzo , Takakura Toru , Miyake Shunsuke , Shinoda Kazuya , Oka Yoshitaka , Saito Yasunori , Kojima Hideki , Hayashi Naoki 
Published: September 2020

PurposeThe beam model in radiation treatment planning systems (RTPSs) plays a crucial role in determining the accuracy of calculated dose distributions. The purpose of this study was to ascertain differences in beam models and their dosimetric influences when a golden beam dataset (GBD) and multi‐institution measured beam datasets (MBDs) are used for beam modeling in RTPSs.MethodsThe MBDs collected from 15 institutions, and the MBDs' beam models, were compared with a GBD, and the GBD’s beam model, for Varian TrueBeam linear accelerator. The calculated dose distributions of the MBDs' beam models were compared with those of the GBD’s beam model for simple geometries in a water phantom. Calculated dose distributions were similarly evaluated in volumetric modulated arc therapy (VMAT) plans for TG‐119 C‐shape and TG‐244 head and neck, at several dose constraints of the planning target volumes (PTVs), and organs at risk.ResultsThe agreements of the MBDs with the GBD were almost all within ±1%. The calculated dose distributions for simple geometries in a water phantom also closely corresponded between the beam models of GBD and MBDs. Nevertheless, there were considerable differences between the beam models. The maximum differences between the mean energy of the energy spectra of GBD and MBDs were −0.12 MeV (−10.5%) in AcurosXB (AXB, Eclipse) and 0.11 MeV (7.7%) in collapsed cone convolution (CCC, RayStation). The differences in the VMAT calculated dose distributions varied for each dose region, plan, X‐ray energy, and dose calculation algorithm. The ranges of the differences in the dose constraints were −5.6% to 3.0% for AXB and −24.1% to 2.8% for CCC. In several VMAT plans, the calculated dose distributions of GBD's beam model tended to be lower in high‐dose regions and higher in low‐dose regions than those of the MBDs' beam models.ConclusionsWe found that small differences in beam data have large impacts on the beam models, and on calculated dose distributions in clinical VMAT plan, even if beam data correspond within ±1%. GBD’s beam model was not a representative beam model. The beam models of GBD and MBDs and their calculated dose distributions under clinical conditions were significantly different. These differences are most likely due to the extensive variation in the beam models, reflecting the characteristics of beam data. The energy spectrum and radial energy in the beam model varied in a wide range, even if the differences in the beam data were <±1%. To minimize the uncertainty of the calculated dose distributions in clinical plans, it was best to use the institutional MBD for beam modeling, or the beam model that ensures the accuracy of calculated dose distributions.
Mechanism and quantitative assessment of saturation transfer for water‐based detection of the aliphatic protons in carbohydrate polymers
Authors: Zhou Yang , van Zijl Peter C.M. , Xu Jiadi , Yadav Nirbhay N. 
Published: September 2020

PurposeCEST MRI experiments of mobile macromolecules, for example, proteins, carbohydrates, and phospholipids, often show signals due to saturation transfer from aliphatic protons to water. Currently, the mechanism of this nuclear Overhauser effect (NOE)‐based transfer pathway is not completely understood and could be due either to NOEs directly to bound water or NOEs relayed intramolecularly via exchangeable protons. We used glycogen as a model system to investigate this saturation transfer pathway in sugar polymer solution.MethodsTo determine whether proton exchange affected saturation transfer, saturation spectra (Z‐spectra) were measured for glycogen solutions of different pH, D2O/H2O ratio, and glycogen particle size. A theoretical model was derived to analytically describe the NOE‐based signals in these spectra. Numerical simulations were performed to verify this theory, which was further tested by fitting experimental data for different exchange regimes.ResultsSignal intensities of aliphatic NOEs in Z‐spectra of glycogen in D2O solution were influenced by hydroxyl proton exchange rates, whereas those in H2O were not. This indicates that the primary transfer pathway is an exchange‐relayed NOE from these aliphatic protons to neighboring hydroxyl protons, followed by the exchange to water protons. Experimental data for glycogen solutions in D2O and H2O could be analyzed successfully using an analytical theory derived for such relayed NOE transfer, which was further validated using numerical simulations with the Bloch equations.ConclusionThe predominant mechanism underlying aliphatic signals in Z‐spectra of mobile carbohydrate polymers is intramolecular relayed NOE transfer followed by proton exchange.
A note on the accuracy of the generalized‐α scheme for the incompressible Navier‐Stokes equations
Authors: Liu Ju , Lan Ingrid S. , Tikenogullari Oguz Z. , Marsden Alison L. 
Published: September 2020

AbstractWe investigate the temporal accuracy of two generalized‐ schemes for the incompressible Navier‐Stokes equations. In a widely‐adopted approach, the pressure is collocated at the time step tn + 1 while the remainder of the Navier‐Stokes equations is discretized following the generalized‐ scheme. That scheme has been claimed to be second‐order accurate in time. We developed a suite of numerical code using inf‐sup stable higher‐order non‐uniform rational B‐spline (NURBS) elements for spatial discretization. In doing so, we are able to achieve high spatial accuracy and to investigate asymptotic temporal convergence behavior. Numerical evidence suggests that only first‐order accuracy is achieved, at least for the pressure, in this aforesaid temporal discretization approach. On the other hand, evaluating the pressure at the intermediate time step recovers second‐order accuracy, and the numerical implementation is simplified. We recommend this second approach as the generalized‐ scheme of choice when integrating the incompressible Navier‐Stokes equations.
A condensed algorithm for adaptive component mode synthesis of viscoelastic flexible multibody dynamics
Authors: Tang Yixuan , Hu Haiyan , Tian Qiang 
Published: September 2020

AbstractA condensed algorithm for adaptive component mode synthesis is proposed to compute the dynamics of viscoelastic flexible multibody systems efficiently and accurately. As studied, the continuous use of modes derived from the initial configuration will lead to poor convergence when dealing with geometric nonlinearity caused by large deformations and overall rotations. The modal reduction at a series of quasi‐static equilibrium configurations should be updated accordingly. According to the loss rate of system energy in the updating process of modal bases, an adaptive mode selection is proposed to reserve the optimal modal bases with their modal number automatically so as to achieve a high‐accuracy simulation. In the proposed condensed iteration algorithm, the order of reduced dynamic equations in the Newton‐Raphson is far less than the number of the unknowns to be discrete in generalized‐α scheme. Using an analytical mapping between the two parts of unknowns, the new algorithm solves a small part of the unknowns iteratively and solves the others noniteratively. Therefore, the saving of time cost comes not only from the proposed adaptive component mode synthesis, but also from the proposed condensed iteration algorithm. The modal bases of subsystems are updated by a series of frame‐like quasi‐static equilibrium configurations independently, in conjunction with the Craig‐Bampton method. Thus, the challenges in the model reduced of extensive ranges of stiffness and damping are removed via the successively updated modal bases. Finally, three numerical tests are made to illuminate the high accuracy and efficiency of the new algorithm proposed.
Weight Reduction Through a Cognitive Behavioral Therapy Lifestyle Intervention in PCOS: The Primary Outcome of a Randomized Controlled Trial
Authors: Jiskoot Geranne , Timman Reinier , Beerthuizen Annemerle , Dietz de Loos Alexandra , Busschbach Jan , Laven Joop 
Published: September 2020

ObjectiveLong‐term weight loss is important and difficult to achieve for many women with polycystic ovary syndrome (PCOS). Lifestyle interventions (LS) in PCOS have shown moderate short‐term effects. Three‐component LS that combine nutrition advice, exercise, and cognitive behavioral therapy have not been tested in long‐term interventions.MethodsWomen (N = 183) with PCOS who were trying to conceive and had BMI > 25 kg/m2 were assigned to 20 group sessions of cognitive behavioral therapy combined with nutrition advice and exercise (LS with or without Short Message Service [SMS] via mobile phone) or care as usual (CAU).ResultsMore weight loss was observed in LS than in CAU (P < 0.001). Adding SMS was even more effective (P = 0.017). In CAU, 13 of 60 (21.8%) succeeded in achieving a 5% weight loss, as did 32 of 60 (52.8%) in LS without SMS and 54 of 63 (85.7%) in LS with SMS. The odds of achieving a 5% weight loss were 7.0 (P < 0.001) in LS compared with CAU. More than 18 of 60 (29.0%) of the women in CAU gained weight versus 5 of 60 (8.5%) and 2 of 63 (3.1%) in LS without or with SMS, respectively. The overall dropout rate was 116 of 183 (63.4%).ConclusionsA three‐component LS program resulted in reasonable weight loss in women with PCOS. Adding SMS resulted in more weight loss.