bluuebunny/crossref_metadata_2025_split huggingface dataset:
A framework for defining FLASH dose rate for pencil beam scanning
Authors: Folkerts Michael M. , Abel Eric , Busold Simon , Perez Jessica Rika , Krishnamurthi Vidhya , Ling C. Clifton 
Published: September 2020

PurposeTo develop a method of (a) calculating the dose rate of voxels within a proton field delivered using pencil beam scanning (PBS), and (b) reporting a representative dose rate for the PBS treatment field that enables correspondence between multiple treatment modalities. This method takes into account the unique spatiotemporal delivery patterns of PBS FLASH radiotherapy.MethodsThe dose rate at each voxel of a PBS radiation field is approximately the quotient of the voxel’s dose and “effective” irradiation time. Each voxel’s “effective” irradiation time starts when the cumulative dose rises above a chosen threshold value, and stops when its cumulative dose reaches its total dose minus the same threshold value. The above calculation yields a distribution of dose rates for the voxels within a PBS treatment field. To report a representative dose rate for the PBS field, we propose a user‐selectable parameter of pth percentile of the dose rate distribution, such that (100 − p) % of the field is above the corresponding dose rate. To demonstrate the method described above, we design FLASH transmission fields using 250 MeV protons and calculate the PBS dose rate distributions in both two‐dimensional (2D) and three‐dimensional (3D) models. To further evaluate the formalism, we provide an example of a clinical PBS treatment field.ResultsWith the 2D PBS transmission field, it is demonstrated that the time to accumulate the total dose at a voxel is limited to a fraction of the delivery time of the entire field. In addition, the spatial distributions of dose and dose rate are quite different within the field. For the 10 × 10 cm2 PBS field irradiating a 3D water phantom, the prescribed dose of 10 Gy at 10 cm depth is delivered in 1.0 s. The dose rate decreases in the irradiated volume with increasing depth (until the Bragg peak) due to increase of beam spot size by Coulomb scattering. For example, 95% of the irradiated volume between 0 and 10 cm depth receive >40 Gy/s, whereas between 0–20 cm and 0–30 cm depth, 95% of the irradiated volume received >36 Gy/s and >24 Gy/s, respectively. For the clinical PBS treatment field, the scanning pattern conforms to the PTV. PBS dose rate data are presented for the PTV and adjacent normal organs.ConclusionWe have developed a method of calculating the dose rate distribution of a PBS proton field and have recommended nomenclature for reporting PBS treatment dose rate. We believe that standardizing the method for calculating and reporting PBS treatment dose rates, in a manner that corresponds with other treatment modalities, will advance the research and potential application of PBS FLASH radiotherapy.
Predicting 3D body shape and body composition from conventional 2D photography
Authors: Tian Isaac Y. , Ng Bennett K. , Wong Michael C. , Kennedy Samantha , Hwaung Phoenix , Kelly Nisa , Liu En , Garber Andrea K. , Curless Brian , Heymsfield Steven B. , Shepherd John A. 
Published: September 2020

PurposeTotal and regional body composition are important indicators of health and mortality risk, but their measurement is usually restricted to controlled environments in clinical settings with expensive and specialized equipment. A method that approaches the accuracy of the current gold standard method, dual‐energy x‐ray absorptiometry (DXA), while only requiring input from widely available consumer grade equipment, would enable the measurement of these important biometrics in the wild, enabling data collection at a scale that would have previously been prohibitive in time and expense. We describe an algorithm for predicting three‐dimensional (3D) body shape and composition from a single frontal 2‐dimensional image acquired with a digital consumer camera.MethodsDuplicate 3D optical scans, two‐dimensional (2D) optical images, and DXA whole‐body scans were available for 183 men and 233 women from the Shape Up! Adults Study. A principal component analysis vector basis was fit to 3D point clouds of a training subset of 152 men and 194 women. The relationship between this vector space and DXA‐derived body composition was modeled with linear regression. The principal component 3D shape was then fitted to match a silhouette extracted from a 2D photograph of a novel body. Body composition was predicted from the resulting 3D shape match using the linear mapping between the principal component parameters and the DXA metrics. Accuracy of body composition estimates from the silhouette method was evaluated against a simple model using height and weight as a baseline, and against DXA measurements as ground truth. Test‐retest precision of the silhouette method was evaluated using the duplicate 2D optical images and compared against precision of the duplicate DXA scans. Paired t‐tests were performed to detect significant differences between the sets.ResultsResults were reported on a held‐out set. Body composition prediction achieved R2s of 0.81 and 0.74 for percent fat prediction of males and females, respectively, on a held‐out test set consisting of 31 males and 39 females. Precision estimates for fat mass were 2.31% and 2.06% for males and females, respectively, compared to 1.26% and 0.68% for DXA scans. The t‐tests revealed no statistically significant differences between the silhouette method measurements and DXA measurements, or between retests.ConclusionTotal and regional body composition measures can be estimated from a single frontal photograph of a human body. Body composition prediction using consumer level photography can enable early screening and monitoring of possible physiological indicators of metabolic disease in regions where medical imagery or clinical assessment is inaccessible.
Achievable dose reductions with gonadal shielding for children and adults during abdominal/pelvic radiographic examinations: A Monte Carlo simulation
Authors: Somasundaram Elanchezhian , Brady Samuel L. , Strauss Keith J. 
Published: September 2020

PurposeRecently, medical professionals have reconsidered the practice of routine gonadal shielding for radiographic examinations. The objective of this study was to evaluate the gonadal dose reduction achievable with gonadal shields in the primary beam during abdominal/pelvic radiographic examinations under ideal and non‐ideal shielding placement.MethodsCT scans of CIRS anthropomorphic phantoms were used to perform voxelized Monte Carlo simulations of the photon transport during abdominal/pelvic radiographic examinations with standard filtration and 0.1 mm Cu + 1 mm Al added filtration to estimate gonadal doses for an adult, 5 yr old, and newborn phantom with and without gonadal shields. The reduction in dose when the shields were not placed at the ideal locations was also evaluated. The ratio of the number of scattered‐to‐primary photons (SPR) across the anteroposterior (AP) dimension of the phantoms was also reported.ResultsThe simulated dose reduction with ideal shielding placement for the testes and ovaries ranged from 80% to 90% and 55% to 70% respectively. For children, a misalignment of the shield to the gonad of 4 cm reduced the measured dose reduction to the gonads to <10%. For adults, this effect did not occur until the misalignment increased to ~6 cm. Effects of dose reduction with and without the gonadal shields properly placed were similar for standard filtration and added filtration. SPR at the level of the testes was consistently <1 for all phantoms. SPR for ovaries was ~1.5 for the adult and 5‐yr old, and ~1 for the newborn phantom.ConclusionDose reduction with ideal alignment of the simulated gonadal shield to the gonads in this study was greater for the testes than the ovaries; both reductions were substantial. However, the dose reductions were greatly reduced (to <10%) for both sexes with misalignment of the gonads to the shields by 4 cm for children and 6 cm for adults.
A spectral method with volume penalization for a nonlinear peridynamic model
Authors: Lopez Luciano , Pellegrino Sabrina F. 
Published: September 2020

AbstractThe peridynamic equation consists in an integro‐differential equation of the second order in time which has been proposed for modeling fractures and damages in the context of nonlocal continuum mechanics. In this article, we study numerical methods for the one‐dimension nonlinear peridynamic problems. In particular we consider spectral Fourier techniques for the spatial domain while we will use the Störmer–Verlet method for the time discretization. In order to overcome the limitation of working on periodic domains due to the spectral techniques we will employ a volume penalization method. The performance of our approach is validated with the study of the convergence with respect to the spatial discretization and the volume penalization. Several tests have been performed to investigate the properties of the solutions.
Welcome Mats and On‐Ramps for Older Adults: The Impact of the Affordable Care Act's Medicaid Expansions on Dual Enrollment in Medicare and Medicaid
Authors: McInerney Melissa , Mellor Jennifer M. , Sabik Lindsay M. 
Published: September 2020

AbstractFor many low‐income Medicare beneficiaries, Medicaid provides important supplemental insurance that covers out‐of‐pocket costs and additional benefits. We examine whether Medicaid participation by low‐income adults age 65 and up increased as a result of Medicaid expansions to working‐age adults under the Affordable Care Act (ACA). Previous literature documents so‐called “welcome mat” effects in other populations but has not explicitly studied older persons dually eligible for Medicare and Medicaid. We extend this literature by estimating models of Medicaid participation among persons age 65 and up using American Community Survey data from 2010 to 2017 and state variation in ACA Medicaid expansions. We find that Medicaid expansions to working‐age adults increased Medicaid participation among low‐income older adults by 1.8 percentage points (4.4 percent). We also find evidence of an “on‐ramp” effect; that is, low‐income Medicare beneficiaries residing in expansion states who were young enough to gain coverage under the 2014 ACA Medicaid expansions before aging into Medicare were 4 percentage points (9.5 percent) more likely to have dual Medicaid coverage relative to similar individuals who either turned 65 before the 2014 expansions or resided in non‐expansion states. This on‐ramp effect is an important mechanism behind welcome mat effects among some older adults.
A comparative study on enhancement of mechanical and tribological properties of nitrile rubber composites reinforced by different functionalized graphene sheets: Molecular dynamics simulations
Authors: Cui Jianzheng , Zhao Jing , Wang Shijie , Li Yunlong 
Published: September 2020

AbstractMolecular dynamics (MD) simulations were adopted to compare the enhanced mechanical and tribological properties of nitrile rubber composites reinforced by different functionalized graphene sheets. Functional groups such as hydroxyl (OH), carboxyl (COOH), and ester (COOCH3) were adopted. The constant strain method was applied to measure the mechanical properties of graphene/nitrile rubber composites. Sandwiched molecular models were developed to investigate the tribological properties of graphene/nitrile rubber composites by applying a shear load. The MD simulation results showed that the incorporation of functionalized graphene enhanced the Young's modulus, bulk modulus, and shear modulus of the nitrile rubber matrix. In addition, the coefficient of friction and abrasion rate of the functionalized graphene/nitrile rubber composites decreased. The mechanisms for the interfacial interactions between the functionalized graphene and nitrile rubber matrix were determined by calculating the mean square displacement of rubber chains, binding energy, and the radial distribution function between functional groups and polar atoms in the rubber matrix, respectively. The results of the atomistic simulations indicated that stronger interfacial interactions and better stability and dispersion of graphene in rubber matrices can be obtained by introducing functionalized graphene. Owing to the combination of hydrogen bonding and strong van der Waals interactions, the COOH‐functionalized graphene behaves the best effect on the enhancement of mechanical and tribological properties of the nitrile rubber composites.
Chromosomal microarray analysis in fetuses with central nervous system anomalies: An 8‐year long observational study from a tertiary care university hospital
Authors: Santirocco Maddalena , Plaja Alberto , Rodó Carlota , Valenzuela Irene , Arévalo Silvia , Castells Neus , Abuli Anna , Tizzano Eduardo , Maiz Nerea , Carreras Elena 
Published: September 2020

AbstractOBJECTIVESTo evaluate the prevalence of DNA copy number variants (CNVs) detected with array comparative genomic hybridization (CGH) in fetuses with central nervous system (CNS) anomalies. Secondary objectives were to describe the prevalence of CNV in specific CNS abnormalities, in isolated defects or associated with other malformations or fetal growth restriction (FGR).METHODSObservational cohort study in 238 fetuses with CNS anomalies in which an array‐CGH had been performed between January 2009 and December 2017. Pathogenic CNV and variants of unknown significance (VUS) were reported.RESULTSPathogenic CNVs were found in 16/238 cases (6.7%), VUS in 18/238 (7.6%), and normal result in 204/238 (85.7%) cases. Pathogenic CNVs were more frequent in posterior fossa anomalies (cerebellar hypoplasia 33%, megacisterna magna 20%), moderate ventriculomegaly (11%) and spina bifida (3.7%). Pathogenic CNVs and VUS were found in 7/182 (3.8%) and 14/182 (7.7%) cases of isolated anomalies, in 9/49 (18.4%) and 4/49 (8.2%) presenting another malformation, and in 0/7 and 0/7 cases with associated FGR (P = .001, P = .741, respectively).CONCLUSIONThese results provide strong evidence toward performing array in fetuses with CNS anomalies, particular in cases of posterior fossa anomalies. The prevalence of pathogenic CNVs is higher in association with other malformations.
Re‐entrant auxetic structures fabricated by fused deposition modeling: An experimental study of influence of process parameters under compressive loading
Authors: Vyavahare Swapnil , Kumar Shailendra 
Published: September 2020

AbstractThe present article is focused on investigating the influence of process parameters under compressive loading in case of reentrant auxetic structures fabricated by fused deposition modeling (FDM). Auxetic structures of acrylonitrile butadiene styrene (ABS) and poly‐lactic acid (PLA) materials are fabricated. Three process parameters of FDM namely layer thickness, raster angle, and number of contours are considered to investigate their influence on compressive strength, stiffness, and specific energy absorption (SEA). Experiments are performed on the basis of central composite design and analysis is performed using ANOVA. It is found that compressive strength of auxetic structure improves with increase in layer thickness. But with increase in raster angle, it increases first and then decreases. Compressive stiffness of structures initially decreases and then increases with increase in raster angle, while it increases with increase in number of contours. SEA of structures increases with decrease in layer thickness. Based on the analysis of experimental results, regression models are developed to predict these responses. Also, multi‐response optimization is performed to optimize strength, stiffness, and SEA. Auxetic structures failed under compressive loading are also examined using scanning electron microscope.
Pilot pragmatic randomized trial of mHealth mindfulness‐based intervention for advanced cancer patients and their informal caregivers
Authors: Kubo Ai , Kurtovich Elaine , McGinnis MegAnn , Aghaee Sara , Altschuler Andrea , Quesenberry Charles , Kolevska Tatjana , Liu Raymond , Greyz‐Yusupov Natalya , Avins Andrew 
Published: September 2020

AbstractObjectiveAssess the feasibility of conducting a cluster randomized controlled trial (RCT) comparing technology‐delivered mindfulness‐based intervention (MBI) programs against a waitlist control arm targeting advanced cancer patients and their informal caregivers.MethodsTwo‐arm cluster RCT within Kaiser Permanente Northern California. We recruited patients with metastatic solid malignancies or hematological cancers and their informal caregivers. Intervention‐group participants chose to use either a commercially available mindfulness app (10–20 min/day) or a webinar‐based mindfulness course for 6 weeks. The waitlist control group received usual care. We assessed feasibility measures and obtained participant‐reported data on quality of life (QoL; primary outcome) and distress outcomes (secondary) pre‐ and postintervention.ResultsA hundred and three patients (median age 67 years; 70% female; 81% White) and 39 caregivers (median age 66 years; 79% female; 69% White) were enrolled. Nearly all participants chose the mindfulness app over the webinar‐based program. Among the participants in the intervention arm who chose the mobile‐app program and completed the postintervention (6‐week) survey, 21 (68%) patients and 7 (47%) caregivers practiced mindfulness at least 50% of the days during the 6‐week study period. Seventy‐four percent of intervention participants were “very” or “extremely” satisfied with the mindfulness program. We observed improvements in anxiety, QoL, and mindfulness among patients in the intervention arm compared to those in the control group.ConclusionsWe demonstrated the feasibility of conducting a cluster RCT of mHealth MBI for advanced cancer patients and their caregivers. Such remote interventions can be helpful particularly during the COVID‐19 pandemic.
HIV and Proteomics: What We Have Learned from High Throughput Studies
Authors: Grabowska Kinga , Harwood Emma , Ciborowski Pawel 
Published: September 2020

AbstractThe accelerated development of technology over the last three decades has driven biological sciences to high‐throughput profiling experiments, now broadly referred to as systems biology. The unprecedented improvement of analytical instrumentation has opened new avenues for more complex experimental designs and expands the knowledge in genomics, proteomics, and other omics fields. Despite the collective efforts of hundreds of researchers, gleaning all the expected information from omics experiments is still quite far. This paper summarizes what has been learned from high‐throughput proteomics studies thus far, and what is believed should be done to reveal even more valuable information from such studies. It is drawn from the background in using proteomics to study human immunodeficiency virus 1 infection of macrophages and/or T cells, but it is believed that some conclusions will be more broadly applicable.
Learning peptide recognition rules for a low‐specificity protein
Authors: Wheeler Lucas C. , Perkins Arden , Wong Caitlyn E. , Harms Michael J. 
Published: September 2020

AbstractMany proteins interact with short linear regions of target proteins. For some proteins, however, it is difficult to identify a well‐defined sequence motif that defines its target peptides. To overcome this difficulty, we used supervised machine learning to train a model that treats each peptide as a collection of easily‐calculated biochemical features rather than as an amino acid sequence. As a test case, we dissected the peptide‐recognition rules for human S100A5 (hA5), a low‐specificity calcium binding protein. We trained a Random Forest model against a recently released, high‐throughput phage display dataset collected for hA5. The model identifies hydrophobicity and shape complementarity, rather than polar contacts, as the primary determinants of peptide binding specificity in hA5. We tested this hypothesis by solving a crystal structure of hA5 and through computational docking studies of diverse peptides onto hA5. These structural studies revealed that peptides exhibit multiple binding modes at the hA5 peptide interface—all of which have few polar contacts with hA5. Finally, we used our trained model to predict new, plausible binding targets in the human proteome. This revealed a fragment of the protein α‐1‐syntrophin that binds to hA5. Our work helps better understand the biochemistry and biology of hA5, as well as demonstrating how high‐throughput experiments coupled with machine learning of biochemical features can reveal the determinants of binding specificity in low‐specificity proteins.
New suitable deprotonating matrices for the analysis of carboxylic acids and some acidic compounds by matrix‐assisted laser desorption/ionization mass spectrometry in negative ion mode
Authors: Krivosheina Mariya S. , Borisov Roman S. , Zhilyaev Dmitry I. , Matveeva Mariya D. , Zaikin Vladimir G. 
Published: September 2020

RationaleDirect non‐derivatization analysis of organic acids and acidic compounds by matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry (MS) in positive ion mode is not always possible due to the low ionization efficiency of analytes. Some new efficient deprotonating matrices were suggested that allowed the production of negative ions from acidic compounds during MALDI‐MS experiments.MethodsVarious tested carboxyl‐containing compounds as well as compounds with acidic properties were mixed with the suggested deprotonating matrices [4‐dimethylaminobenzaldehyde (DMABA), N,N‐dimethylamino‐p‐phenylenediamine or 3‐aminoquinoline] and applied on a standard MALDI target followed by recording MALDI mass spectra in negative ion mode.ResultsAll the tested acidic compounds mixed with the suggested deprotonating matrices produced abundant [M − H]− ions under MALDI conditions. DMABA produced the strongest signals reflecting greater sensitivity of analysis.ConclusionsThe suggested deprotonating matrices are commercially available compounds and are good alternatives to well‐known matrices of this kind and, in particular, the often used 9‐aminoacridine. DMABA is the best of the tested potential matrices and is suitable for the detection of low molecular weight carboxyl‐containing compounds, substituted phenols, and mixtures of naphthenic acids by (−)MALDI‐MS.
First in‐human experience with a novel robotic platform and Magnetic Surgery System
Authors: Barajas‐Gamboa Juan S. , Huidobro Felipe , Jensen Joaquin , Luengas Rafael , Rodriguez John , Abril Carlos , Corcelles Ricard , Kroh Matthew 
Published: September 2020

AbstractBackgroundMagnetic technologies have been introduced to reduce invasiveness of surgical procedures. This study was aimed to analyse the performance of a novel combined magnetic‐robotic controller as an enhanced accessory to the Magnetic Surgical System in laparoscopic cholecystectomy (LC).MethodsThis was a prospective study of 10 consecutive patients undergoing LC with this novel surgical system.ResultsTen patients were included, nine were female. The mean age was 30.3 ± 9 years. All patients had chronic cholecystitis. Procedures were completed successfully. The median operative time was 50 ± 11 min. The system performed effectively in all cases with no need of additional interventions. There were no device‐related complications or side effects. All patients were discharged the same day. Recovery was uneventful during follow‐up.ConclusionsThis study demonstrates the first in‐human successful performance of surgeries utilizing a novel combination of magnetic and robotic technologies in one integrated system.