bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wideband high‐gain multiresonance antenna based on polarization‐dependent metasurface
Authors: Chen Dongxu , Yang Wanchen , Xue Quan , Che Wenquan 
Published: September 2020

AbstractIn this article, a novel polarization‐dependent metasurface (PDMS) structure is presented and applied to realize a wideband high‐gain antenna with multiple resonances. The PDMS element is obtained by cutting slots into the square patch unit cell of conventional metasurface (MS). Very different from the conventional MS structure, the proposed PDMS element exhibits different reflection phases and resonance frequencies, depending on the polarization state of the incident plane wave. By properly tailoring the reflection‐phase curves under different polarizations, a proper PDMS structure is introduced. Then, by arranging the PDMS elements along different orientations, a multiresonance radiator can be realized. When applying the proposed radiator to the slot‐coupled MS antenna, one broadband PDMS‐based antenna with multiple adjacent resonance frequencies can be realized by the combination of coupling slot‐mode and PDMS modes. For verification, a PDMS radiator with 4 × 4 unit cells is designed accordingly and applied to realize one C‐band broadband PDMS‐based antenna in a low profile (0.06 λ0). The measured results of the fabricated prototype PDMS‐based antenna exhibit a large –10 dB impedance bandwidth of 55% (4.31‐7.58 GHz), a maximum available gain of 10.898 dBi, and a 2‐dB gain bandwidth of 30.81% (5.1‐6.96 GHz).
Deterministic linear Boltzmann transport equation solver for patient‐specific CT dose estimation: Comparison against a Monte Carlo benchmark for realistic scanner configurations and patient models
Authors: Principi Sara , Wang Adam , Maslowski Alexander , Wareing Todd , Jordan Petr , Schmidt Taly Gilat 
Published: September 2020

PurposeEpidemiological evidence suggests an increased risk of cancer related to computed tomography (CT) scans, with children exposed to greater risk. The purpose of this work is to test the reliability of a linear Boltzmann transport equation (LBTE) solver for rapid and patient‐specific CT dose estimation. This includes building a flexible LBTE framework for modeling modern clinical CT scanners and to validate the resulting dose maps across a range of realistic scanner configurations and patient models.MethodsIn this study, computational tools were developed for modeling CT scanners, including a bowtie filter, overrange collimation, and tube current modulation. The LBTE solver requires discretization in the spatial, angular, and spectral dimensions, which may affect the accuracy of scanner modeling. To investigate these effects, this study evaluated the LBTE dose accuracy for different discretization parameters, scanner configurations, and patient models (male, female, adults, pediatric). The method used to validate the LBTE dose maps was the Monte Carlo code Geant4, which provided ground truth dose maps. LBTE simulations were implemented on a GeForce GTX 1080 graphic unit, while Geant4 was implemented on a distributed cluster of CPUs.ResultsThe agreement between Geant4 and the LBTE solver quantifies the accuracy of the LBTE, which was similar across the different protocols and phantoms. The results suggest that 18 views per rotation provides sufficient accuracy, as no significant improvement in the accuracy was observed by increasing the number of projection views. Considering this discretization, the LBTE solver average simulation time was approximately 30 s. However, in the LBTE solver the phantom model was implemented with a lower voxel resolution with respect to Geant4, as it is limited by the memory of the GPU. Despite this discretization, the results showed a good agreement between the LBTE and Geant4, with root mean square error of the dose in organs of approximately 3.5% for most of the studied configurations.ConclusionsThe LBTE solver is proposed as an alternative to Monte Carlo for patient‐specific organ dose estimation. This study demonstrated accurate organ dose estimates for the rapid LBTE solver when considering realistic aspects of CT scanners and a range of phantom models. Future plans will combine the LBTE framework with deep learning autosegmentation algorithms to provide near real‐time patient‐specific organ dose estimation.
Adaptive slice‐specific z‐shimming for 2D spoiled gradient‐echo sequences
Authors: Soellradl Martin , Strasser Johannes , Lesch Andreas , Stollberger Rudolf , Ropele Stefan , Langkammer Christian 
Published: September 2020

PurposeTo reduce the misbalance between compensation gradients and macroscopic field gradients, we introduce an adaptive slice‐specific z‐shimming approach for 2D spoiled multi‐echo gradient‐echoe sequences in combination with modeling of the signal decay.MethodsMacroscopic field gradients were estimated for each slice from a fast prescan (15 seconds) and then used to calculate slice‐specific compensation moments along the echo train. The coverage of the compensated field gradients was increased by applying three positive and three negative moments. With a forward model, which considered the effect of the slice profile, the z‐shim moment, and the field gradient, maps were estimated. The method was evaluated in phantom and in vivo measurements at 3 T and compared with a spoiled multi‐echo gradient‐echo and a global z‐shimming approach without slice‐specific compensation.ResultsThe proposed method yielded higher SNR in maps due to a broader range of compensated macroscopic field gradients compared with global z‐shimming. In global white matter, the mean interquartile range, proxy for SNR, could be decreased to 3.06 s−1 with the proposed approach, compared with 3.37 s−1 for global z‐shimming and 3.52 s−1 for uncompensated multi‐echo gradient‐echo.ConclusionAdaptive slice‐specific compensation gradients between echoes substantially improved the SNR of maps, and the signal could also be rephased in anatomical areas, where it has already been completely dephased.
An efficient transient‐state algorithm for evaluation of leakage through defective cutoff walls
Authors: Pan Yutao , Hicks Michael A. , Broere Wout 
Published: September 2020

AbstractArtificial barriers are widely used to prevent leakages. However, due to construction errors during the wall installation, passages with small dimensions may occasionally penetrate through the barrier, undermining its tightness. A three‐dimensional discretized algorithm (TDA) is proposed for quantitatively estimating the transient‐state discharge rate through defective cutoff walls. By discretizing the wall into a three‐dimensional refined mesh grid, the algorithm enables an examination of penetrating passages, an evaluation of defect dimensions, and an estimation of discharge rate through the penetrating passages. A rigorous realization‐by‐realization comparison between the TDA and the finite element method (FEM) was made, and it was found that the TDA results show strong correlations with the FEM results, but at a remarkably lower (1/103‐1/104) computational cost. The TDA generally gives a discharge rate that is 0.1‐1.0 times greater than its FEM counterpart, as the lengthened seepage distance due to random corrugations in the penetrating untreated zone cannot be replicated by the TDA.
Transport analysis in deformable porous media through integral transforms
Authors: Bonazzi Alessandra , Jha Birendra , de Barros Felipe P. J. 
Published: September 2020

AbstractGeomechanical deformation can alter the flow field that impacts solute mass fluxes. Despite its importance, the effects of the coupling between geomechanical deformation and the flow field on solute transport behavior are not fully known. In this paper, we study the impact of this coupling on the solute concentration distribution. The concentration field is semianalytically derived by making use of the generalized integral transform technique. We apply the semianalytical solution to two uniaxial consolidation problems, the classical Terzaghi's problem with a constant load and the case of periodic loading of a porous deformable layer. Our results indicate that geomechanical parameters, such as the Skempton's coefficient and the soil compressibility, can affect the peak concentration as well as the spatial moments of solute plume. In case of periodic loading, we show that the frequency of loading also plays a key role in regulating the temporal dynamics of the concentration field.
On minimizing downside risk in make‐to‐stock, risk‐averse firms
Authors: Li Bo , Arreola‐Risa Antonio 
Published: September 2020

AbstractConsider a single‐product, make‐to‐stock, risk‐averse firm with stochastic demand and manufacturing capacity. Temporarily unfilled demands are back‐ordered. Total cost is equal to the sum of inventory‐holding and back‐ordering costs over a continuous‐time, finite planning horizon. In this article, we study the problem of finding the base‐stock level that minimizes total cost conditional value‐at‐risk (CVaR), or total cost CVaR for short. We demonstrate that total cost CVaR is both convex in the base‐stock level and increasing in risk aversion. We derive a closed‐form approximation of total cost which is asymptotically exact in the planning horizon length. The approximation leads to a relatively simple determination of optimal base‐stock levels which are reasonably accurate for practical applications. We make observations and identify findings regarding the impact on optimal base‐stock levels of changes in risk aversion, manufacturing capacity, inventory‐holding and back‐ordering costs, and planning horizon length. We provide a detailed description of how our research results were applied in a real‐world, supply‐chain design project.
Revisiting the Evidence for the Reuse of Enteral Feeding Equipment in Ambulatory Patients: A Systematic Review
Authors: Osland Emma J. , Andersen Sarah , Coleman Emma , Marshall Belinda 
Published: September 2020

AbstractBackgroundThe reuse of enteral tube feeding (ETF) equipment is not recommended due to the risk of microbial contamination and subsequent risk of infection; however, this practice continues in many ambulatory settings. A systematic review of the literature was undertaken to review the evidence underpinning the cleaning and reuse of ETF equipment.MethodsStudies that investigated the reuse, decontamination, and/or cleaning of ETF equipment were considered for inclusion. Electronic databases were searched (no limits were placed on date of publication, age, or duration of reuse). Extracted data were assessed using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) and reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta‐Analyses recommendations.ResultsTen studies met inclusion criteria: 3 investigated changes to clinical outcomes with extending reuse from 24 to ≤72 hours using water rinses; 5 considered the efficacy of various cleaning methods assessed in laboratory conditions; 2 used a combination of both approaches. Sufficient data to allow GRADE assessment was found only for bottle‐type containers.ConclusionsA very low level of evidence supports the cleaning and reuse of rigid and "unspecified" bottle containers; no studies were found to inform the reuse of syringes used for bolus feeding or any equipment used for water infusion or flushes. There is an absence of literature evaluating the safety and clinical outcomes of cleaning and reusing ETF equipment, and research is required to support equipment reuse.
A simple Galerkin meshless method, the Fragile Points method using point stiffness matrices, for 2D linear elastic problems in complex domains with crack and rupture propagation
Authors: Yang Tian , Dong Leiting , Atluri Satya N. 
Published: September 2020

SummaryThe Fragile Points method (FPM) is an elementarily simple Galerkin meshless method, employing Point‐based discontinuous trial and test functions only, without using element‐based trial and test functions. In this study, the algorithmic formulations of FPM for linear elasticity are given in detail, by exploring the concepts of point stiffness matrices and numerical flux corrections. Advantages of FPM for simulating the deformations of complex structures, and for simulating complex crack propagations and rupture developments, are also thoroughly discussed. Numerical examples of deformation and stress analyses of benchmark problems, as well as of realistic structures with complex geometries, demonstrate the accuracy, efficiency, and robustness of the proposed FPM. Simulations of crack initiation and propagations are also given in this study, demonstrating the advantages of the present FPM in modeling complex rupture and fracture phenomena. The crack and rupture propagation modeling in FPM is achieved without remeshing or augmenting the trial functions as in standard, extended, or generalized finite element method. The simulation of impact, penetration, and other extreme problems by FPM will be discussed in our future articles.
Buprenorphine is a weak dopamine releaser relative to heroin, but its pretreatment attenuates heroin‐evoked dopamine release in rats
Authors: Isaacs Dominic P. , Leman Ryan P. , Everett Thomas J. , Lopez‐Beltran Hendrick , Hamilton Lindsey R. , Oleson Erik B. 
Published: September 2020

AbstractAimsThe United States of America is currently in an opioid epidemic. Heroin remains the most lethal opioid option with its death rate increasing by over 500% in the last decade. The rewarding and reinforcing effects of heroin are thought to be mediated by its ability to increase dopamine concentration in the nucleus accumbens shell. By activating Gi/o‐coupled μ‐opioid receptors, opioids are thought to indirectly excite midbrain dopamine neurons by removing an inhibitory GABAergic tone. The partial μ‐opioid receptor agonist buprenorphine is a substitution‐based therapy for heroin dependence that is thought to produce a steady‐state level of μ‐opioid receptor activation. But it remains unclear how buprenorphine alters dopamine release relative to heroin and how buprenorphine alters the dopamine‐releasing effects of heroin. Because buprenorphine is a partial agonist at the μ‐opioid receptor and heroin is a full agonist, we predicted that buprenorphine would function as a weak dopamine releaser relative to heroin, while functioning as a competitive antagonist if administered in advance of heroin.MethodsWe performed fast‐scan cyclic voltammetry in awake and behaving rats to measure how heroin, buprenorphine HCl, and their combination affect transient dopamine release events in the nucleus accumbens shell. We also performed a complimentary pharmacokinetic analysis comparing opioid plasma levels at time points correlated to our neurochemical findings.ResultsBoth buprenorphine and heroin produced changes in the frequency of transient dopamine release events, although the effect of buprenorphine was weak and only observed at a low dose. In comparison with vehicle, the frequency of dopamine release events maximally increased by ~25% following buprenorphine treatment and by ~60% following heroin treatment. Distinct neuropharmacological effects were observed in the high‐dose range. The frequency of dopamine release events increased linearly with heroin dose but biphasically with buprenorphine dose. We also found that buprenorphine pretreatment occluded the dopamine‐releasing effects of heroin, but plasma levels of buprenorphine had returned to baseline at this time point.ConclusionThese findings support the notion that low‐dose buprenorphine is a weak dopamine releaser relative to heroin and that buprenorphine pretreatment can block the dopamine‐releasing effects of heroin. The finding that high‐dose buprenorphine fails to increase dopamine release might explain its relatively low abuse potential among opioid‐dependent populations. Because high‐dose buprenorphine decreased dopamine release before occluding heroin‐evoked dopamine release, and buprenorphine was no longer detected in plasma, we conclude that the mechanisms through which buprenorphine blocks heroin‐evoked dopamine release involve multifaceted pharmacokinetic and pharmacodynamic interactions.
Efficient approximation algorithm for the Schrödinger–Possion system
Authors: He Xuefei , Wang Kun 
Published: September 2020

AbstractIn this article, we study an efficient approximation algorithm for the Schrödinger–Possion system arising in the resonant tunneling diode (RTD) structure. By following the classical Gummel iterative procedure, we first decouple this nonlinear system and prove the convergence of the iteration method. Then via introducing a novel spatial discrete method, we solve efficiently the decoupled Schrödinger and Possion equations with discontinuous coefficients on no‐uniform meshes at each iterative step, respectively. Compared with the traditional ones, the algorithm considered here not only has a less restriction on the discrete mesh, but also is more accurate. Finally, some numerical experiments are shown to confirm the efficiency of the proposed algorithm.
Community stakeholders’ perspectives regarding acceptability of a life skills building intervention to empower women in Pakistan
Authors: Ali Tazeen Saeed , Karmaliani Rozina , Shah Nasim Zahid , Bhamani Shireen Shehzad , Khuwaja Hussain Maqbool Ahmed , McFarlane Judith , Wadani Zahid Hyder , Kulane Asli 
Published: September 2020

AbstractViolence against women (VAW) is a major determinant in the assessment of a women's mental health. Many interventions have addressed strategies to reduce VAW, however, little information is available regarding effectiveness in the local context, particularly the role of men in women's empowerment. In Pakistan, a qualitative approach was undertaken in all four of its provinces to describe the community residents’, both men and women, perceptions regarding the acceptability of a proposed life skills building (LSB) intervention involving men's engagement with regards to women's empowerment and VAW. Eighteen focus group discussions were conducted with men and women from locales within each province of Pakistan, averaging 6–10 participants per group. Fourteen key informant interviews were conducted with community stakeholders. The analysis identified three major themes: family life and male engagement, LSB training as an empowerment tool, and operationalization of the proposed LSB intervention. The proposed LSB intervention was well accepted by the participants with a strong urge to engage men in receiving the LSB training sessions. Men's engagement has been identified as an important element to facilitate women's empowerment. Participants suggested that these sessions should be held for two and a half hours per week within the community public spaces. In addition, these sessions should be based on an interactive approach. The focus of these sessions should include ideas surrounding positive relationships and economic skills building. Moreover, men's engagement will help to reduce VAW and improve the mental health of women in a patriarchal country like Pakistan.
The relationship between abdominal fat and change in left ventricular ejection fraction in cancer patients
Authors: Reding Kerryn W. , Ghemigian Khristine , Carbone Salvatore , D'Agostino Ralph , Jordan Jennifer H. , Meléndez Giselle , Lamar Zanetta S. , Klepin Heidi D. , Thomas Alexandra , Langford Dale , Vasu Sujethra , Hundley W. Gregory 
Published: September 2020

AbstractObjectivesPrior studies have identified a relationship between body mass index (BMI) and intraperitoneal (IP) fat with heart failure; however, in prior studies of cancer patients receiving potentially cardiotoxic chemotherapy, elevations in BMI have not necessarily been associated with decrements in heart function. This study tested the hypothesis that IP fat may be associated with left ventricular ejection fraction (LVEF) decline among cancer patients receiving potentially cardiotoxic chemotherapy.MethodsIn this prospective study of 61 cancer patients (23 breast cancer, 32 lymphoma, and 6 sarcoma), IP fat and other assessments of body composition, and changes in LVEF from pre‐ to postcancer treatment using noninvasive magnetic resonance imaging was ascertained.ResultsAfter accounting for age, baseline LVEF, and confounding variables, pre‐ to 24‐month post‐treatment LVEF changes were inversely correlated with IP fat (r = −0.33; p = 0.02) and positively correlated with measures of subcutaneous (SQ) fat (r = 0.33; p = 0.01). These LVEF changes were not correlated with BMI (r = 0.12; p = 0.37).ConclusionAmong patients receiving potentially cardiotoxic chemotherapy, pretreatment IP fat was associated with subsequent declines in LVEF. There was no association between BMI and LVEF decline. These findings may be related to a potential protective effect of SQ fat.
Biofiber‐reinforced polymeric hybrid composites: An overview on mechanical and tribological performance
Authors: Chandgude Swapnil , Salunkhe Sachin 
Published: September 2020

AbstractThis article presents a thorough review of biofiber‐based hybrid composites along with the discussion on its mechanical and tribological performance in the polymeric matrix. Emphasis is centered on plant fibers as animal fibers are not frequently used and mineral fibers possess serious health issues. All five types of plant fibers and their hybrids are reviewed. Hybridization of plant fibers synergetically combines individual benefits while eliminating the limitations of single fiber use. Study regarding fiber origin, processability and extraction techniques, composition, chemical surface treatments, and applications are presented. Finally, the results obtained are summarized and future developments are discussed. The review concludes that biofiber hybrid composites possess great potential in several applications provided that satisfies design constraints and polymeric matrix compatibility issues.
Comparative pharmacokinetics of Ding‐Zhi‐Xiao‐Wan preparation and its single herbs in rats by using a putative multiple‐reaction monitoring UPLC‐MS/MS method
Authors: Sun Yufei , He Yang , Liu Shuxin , Gao Hongxue , Pi Zifeng , Song Fengrui , Liu Zhiqiang , Liu Shu 
Published: September 2020

AbstractIntroductionThe formula of Chinese medicine, Ding‐Zhi‐Xiao‐Wan (DZXW), has the distinct feature of compatibility therapy, which is attributed to the interactions of multi‐herbs. However, the quantification problem caused by the absence of pure reference standards is a bottleneck to clarify the compatibility advantages from the perspective of pharmacokinetics (PKs).ObjectiveThis study aimed to develop a putative multiple‐reaction monitor (PMRM) strategy for exploring the comparative PKs of DZXW and its single herbs.MethodsFirst, precursor ion and tandem mass spectrometry (MS/MS) chromatograms were obtained via ultra‐high‐performance liquid chromatography coupled with quadrupole time‐of‐flight MS (UHPLC–Q‐TOF‐MS) under different collision energy (CE) values. Then, the two most abundance ions in the MS/MS chromatograms were chosen as product ions, and CE values were selected according to the abundance of the product ion peaks. Next, a PMRM strategy consisting of optimal MRM parameters was constructed. Finally, the established PMRM parameters were imported to UHPLC coupled with triple quadrupole MS (UHPLC–TQ‐MS) for quantification.ResultsThe strategy was exemplified by the comparative PK study of DZXW and its single herbs. This strategy could extend the PK scopes of multi‐components. The quantitative results displayed substantial variations in PK parameters between DZXW and its single herbs.ConclusionThe PK parameters indicated that the DZXW formula could increase the exposure levels of most ingredients and reduce the maximum concentration (Cmax) of Radix Polygala, indicating that herb compatibility could produce synergistic effects and diminish possible toxic effects. This study provides a viable orientation for the compatibility investigation of traditional Chinese medicine.