bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prevalence of Olfactory Dysfunction in Coronavirus Disease 2019 (COVID‐19): A Meta‐analysis of 27,492 Patients
Authors: Saniasiaya Jeyasakthy , Islam Md Asiful , Abdullah Baharudin 
Published: November 2020

Objectives/HypothesisOlfactory dysfunction has been observed as one of the clinical manifestations in COVID‐19 patients. We aimed to conduct a systematic review and meta‐analysis to estimate the overall pooled prevalence of olfactory dysfunction in COVID‐19 patients.Study DesignSystematic review and meta‐analyses.MethodsPubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between 1 December 2019 and 23 July 2020. We used random‐effects model to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I2 statistic and Cochran's Q test. Robustness of the pooled estimates was checked by different subgroup and sensitivity analyses This study is registered with PROSPERO (CRD42020183768).ResultsWe identified 1162 studies, of which 83 studies (n = 27492, 61.4% female) were included in the meta‐analysis. Overall, the pooled prevalence of olfactory dysfunction in COVID‐19 patients was 47.85% [95% CI: 41.20–54.50]. We observed olfactory dysfunction in 54.40% European, 51.11% North American, 31.39% Asian, and 10.71% Australian COVID‐19 patients. Anosmia, hyposmia, and dysosmia were observed in 35.39%, 36.15%, and 2.53% of the patients, respectively. There were discrepancies in the results of studies with objective (higher prevalence) versus subjective (lower prevalence) evaluations. The discrepancy might be due to false‐negative reporting observed in self‐reported health measures.ConclusionsThe prevalence of olfactory dysfunction in COVID‐19 patients was found to be 47.85% based on high‐quality evidence. Due to the subjective measures of most studies pooled in the analysis, further studies with objective measures are advocated to confirm the finding.Level of Evidence2 Laryngoscope, 131:865–878, 2021
Responses of plant, soil bacterial and fungal communities to grazing vary with pasture seasons and grassland types, northern Tibet
Authors: Zhang Haorui , Fu Gang 
Published: November 2020

AbstractSynthetic responses of plant and soil microbial communities to grazing are indefinite in alpine grasslands on the Tibetan Plateau. Three paired, fenced and free grazing sites (alpine steppe meadow for winter pasture [ASMWP]; alpine steppe meadow for summer pasture [ASMSP]; alpine meadow for summer pasture [AMSP]) were used to compare how pasture season and grassland type affect responses of the α‐diversity and community composition of plant, soil bacteria and fungi to grazing. Cold‐season grazing reduced soil moisture by 12.10%, ammonium nitrogen (NH4+‐N) by 53.71%, the ratio of available nitrogen to phosphorus by 64.11%, species richness (SR) by 31.4% and the Shannon by 11.9% of plant community on the ASMWP. Warm‐season grazing reduced nitrate nitrogen by 30.45%, SR of soil bacterial community by 21.98% on the ASMSP, but increased soil NH4+‐N by 90.02% on the AMSP. Warm‐season grazing‐induced changes in plant community composition were mainly related to the composition of forbs on the AMSP. Grazing‐induced changes in the community composition of soil bacteria were mainly related to Proteobacteria, Acidobacteria, Bacteroidetes, Firmicutes and Verrucomicrobia on the ASMWP, and Proteobacteria, Acidobacteria, Bacteroidetes, Chloroflexi and TM7 on the ASMSP. Grazing‐induced changes in the community composition of soil fungi were mainly related to Ascomycota and Basidiomycota on the ASMWP, Basidiomycota on the ASMSP and Ascomycota on the AMSP. Therefore, the effects of grazing on plant and soil microbial communities may vary with grassland types and pasture seasons, which may be related to grazing‐induced changes in available nitrogen, the ratio of available nitrogen to phosphorus and soil moisture.
The potential role of turbulence in modulating the migration of demersal zooplankton
Authors: Tanaka Mamoru , Genin Amatzia , Endo Yoshinari , Ivey Gregory N. , Yamazaki Hidekatsu 
Published: November 2020

AbstractDespite suggestions that turbulence can affect the migration of zooplankton, field observations of such effects are scarce. This is especially the case for bottom‐associated (demersal) zooplankton that reside in the typically turbulent near‐bottom environment. Using moored sensors deployed at two coastal sites in the North Pacific and the Red Sea, we present observations of the effects of turbulence on the nocturnal emergence of demersal zooplankton. A cabled observatory consisting of a plankton camera, an acoustic current profiler and environmental sensors, was deployed near bottom in 20 m of water near Oshima Island, Japan. Observations were also obtained from a second site near a coral reef in 16 m of water in the Red Sea. Acoustic backscatter data obtained from current profilers at both sites provided a proxy for zooplankton density. Combined with simultaneous estimates of turbulence intensity, the observations suggest that the nocturnal emergence of demersal zooplankton was hindered by elevated levels of turbulence. While our findings are inferred from acoustic data, agreement between the two different sites supports our hypothesis that demersal zooplankton may remain near the bed during times of strong turbulence.
Biodegradable oxygen biosensors via electrospinning
Authors: Cybyk Daniel B. , Reinsch Bonnie M. , Presley Kayla F. , Schweller Ryan M. , Tedeschi Andrea , Burns Teresa , Chaparro Francisco J. , Ly Jack T. , Dalton Matthew J. , Lozano Monica , Grusenmeyer Tod A. , Lannutti John J. 
Published: November 2020

AbstractMonitoring oxygenation in vivo is critical to ensuring human health, particularly in the context of ‘silent’ hypoxia. Utilizing blends of biodegradable polycaprolactone (PCL) and gelatine, we sought to develop an electrospun oxygen sensor that maintains the advantages of robust, phosphorescent oxygen‐sensing chromophores while providing resorbable polymeric scaffolds benefiting from tailorable degradation times ranging from hours to weeks. Electrospun sensors successfully provide accurate oxygen measurements for periods >1 month. In vitro testing took place in a custom aqueous testing system over five weeks in 37°C phosphate‐buffered saline (PBS); dissolved oxygen concentrations were maintained at 0–5% O2 where physoxia characteristic of the subdermal environment is defined as 2–5% O2. Excited state chromophore lifetime (τ) is quenched in the presence of dissolved diatomic oxygen and is influenced by characteristics of the surrounding matrix. The observed final deoxygenated τ (τ0) values were split into 3 groups: polysulphone (PSU)‐PCL (~397 µs) >75:25, 50:50 and 25:75 PCL:gelatine (~191–182 µs) > PCL, 10:90 PCL:gelatine, 1:99 crosslinked PCL:gelatine (~145–135 µs). Highly linear Stern–Volmer activity enabling accurate and precise calibration was observed even after 35 days of exposure; this proves that non‐core–shell fibres consisting of blends of PCL and gelatine can yield predictable lifetime values for >30 days in vitro. Scanning electron microscopy and mass loss data revealed that sensor degradation is highly tailorable, allowing for the fabrication of sensors engineered for a specific biomedical time frame. In contrast, core–shell fibre sensors showed more variability in lifetime following internal degradation likely caused by caproic acid entrapment by the PCL ‘shell’. This work demonstrates that biodegradable and biocompatible optically monitored sensors can be fabricated to provide direct, accurate assessments of oxygenation, even as the sensor platform degrades in a controlled manner. Such technologies have the potential to substantially change respiratory disease management.
Single pencil beam benchmark of a module for Monte Carlo simulation of proton transport in the PENELOPE code
Authors: Verbeek Nico , Wulff Jörg , Bäumer Christian , Smyczek Sabrina , Timmermann Beate , Brualla Lorenzo 
Published: November 2020

Background and purposePENH is a recently coded module for simulation of proton transport in conjunction with the Monte Carlo code PENELOPE. PENELOPE applies class II simulation to all type of interactions, in particular, to elastic collisions. PENH uses calculated differential cross sections for proton elastic collisions that include electron screening effects as well as nuclear structure effects. Proton‐induced nuclear reactions are simulated from information in the ENDF‐6 database or from alternative nuclear databases in ENDF format. The purpose of this work is to benchmark this module by simulating absorbed dose distributions from a single finite spot size proton pencil beam in water.Materials and methodsMonte Carlo simulations with PENH are compared with simulation results from TOPAS Monte Carlo (v3.1p2) and RayStation Monte Carlo (v6). Different beam models are examined in terms of mean energy and energy spread to match the measured profiles. The phase‐space file is derived from experimental measurements. Simulated absorbed dose distributions are compared to experimental data obtained with the ionization chamber array MatriXX 2D detector (IBA Dosimetry) in a water tank. The experiments were conducted with a clinical IBA pencil beam scanning dedicated nozzle. In all simulations a Fermi‐Eyges phase‐space representation of a single finite spot size proton pencil beam is used.ResultsIn general, there is a good agreement between simulated results and experimental data up to a distance of 3 cm from the central axis. In the core region (region where the dose is more than 10% of the maximum dose) PENH shows, overall, the smallest deviations from experimental data, with the largest radial rms (root mean square) smaller than 0.2. The results achieved by TOPAS and RayStation in that region are very close to those of PENH. For the halo region, that is the area of the dose distribution outside the core region reaching down to 0.01% of the maximum intensity, the largest rms achieved by TOPAS is always smaller than 0.5, yielding better results than the rest of the codes.ConclusionThe physics modeling of the PENELOPE/PENH code yields results consistent with measurements in the dose range relevant for proton therapy. The discrepancies between PENH appearing at distances larger than 3 cm from the central‐beam axis are accountable to the lack of neutron simulation in this code. In contradistinction, TOPAS has a better agreement with experimental data at large distances from the central‐beam axis because of the simulation of neutrons.
Imaging of polarized components of Cerenkov light and luminescence of water during carbon‐ion irradiation
Authors: Yamamoto Seiichi , Yabe Takuya , Akagi Takashi , Hirano Yoshiyuki 
Published: November 2020

PurposeThe luminescence image of water during the irradiation of carbon ions showed higher intensity at shallow depths than dose distribution due to the contamination of Cerenkov light from secondary electrons. Since Cerenkov light is coherent and polarized for the light produced during the irradiation of carbon ions to water, the reduction of Cerenkov light may be possible with a polarizer. In addition, there is no information on the polarization of the luminescence of water. To clarify these points, we measured the optical images of water during the irradiation of carbon ions with a polarizer by changing the directions of the transmission axis.MethodsImaging was conducted using a cooled charge‐coupled device (CCD) camera during the irradiation of 241.5 MeV/n energy carbon ions to a water phantom with a polarizer in front of the lens by changing the transmission axis parallel and perpendicular to the carbon‐ion beam.ResultsWith the polarizer parallel to the carbon‐ion beam, the intensity at the shallow depth was ~26% higher than that measured with the polarizer perpendicular to the beam. We found no significant intensity difference between these two images at deeper depths where the Cerenkov light was not included. The difference image of the parallel and perpendicular directions showed almost the same image as the simulated Cerenkov light distribution. Using the measured difference image, correction of the Cerenkov component was possible from the measured luminescence image of water during the irradiation of carbon ions.ConclusionWe could measure the difference of the Cerenkov light component by changing the transmission axis of the polarizer. Also we clarified that there was no difference in the luminescence of water by changing the transmission axis of the polarizer.
Internal dosimetry of [99mTc]NTP15‐5 radiotracer for cartilage imaging in preclinical and clinical models using the GATE Monte Carlo platform
Authors: Fois Giovanna Rosa , Valla Clémence , Jouberton Elodie , Sas Nicolas , Billoux Tommy , Auzeloux Philippe , Cachin Florent , Miot‐Noirault Elisabeth , Maigne Lydia 
Published: November 2020

PurposeThis study aims to perform dosimetry for [99mTc]NTP15‐5 radiotracer used in imaging of articular cartilage in rabbits and humans. The radiotracer (covered by a world patent WO 01/00621 A1) has been proposed in the previous years for the study of cartilage in osteoarthritis diseases. A sensitive imaging approach is essential to quantify osteoarthritis progression and monitor response to new therapies. [99mTc]NTP15‐5 binds to cartilage proteoglycans whose decreased content is associated to a loss of biomedical function of cartilage. We have implemented the whole dosimetry study concerning this new radiotracer for rabbits and humans using the GATE Monte Carlo platform.Materials and methodsAbsorbed doses to critical organs are determined using the MIRD formalism. Biodistribution data are obtained by organ sampling, measuring the activity in organs for three rabbits sacrificed at various times postadministration, and by SPECT/CT imaging at different times after injection. Most important sources are cartilages (in knees and intervertebral discs), due to localization together with the liver and kidneys due to excretion of the agent. S‐values are calculated from rabbit’s CT scan and human CT scan using the GATE v8.0 Monte Carlo platform. Cumulated activity in humans is extrapolated from animals using the %kg‐dose/g method. Particular attention is given to dose calculation in bones, bone marrow and organs at risk.ResultsThe dosimetry performed in rabbits shows highest absorbed doses for liver and kidneys with respectively 22.5 and 43.8 µGy per MBq of injected activity. In humans, we found absorbed doses for a maximum injected activity of 15 MBq/kg, that is, 1050 MBq for an adult of 70 kgs of 9.03 mGy for kidneys and 4.16 mGy for knee cartilages. Effective dose is 2.69 µSv/MBq.ConclusionsThe dosimetry profile of [99mTc]NTP15‐5 in the context of preclinical trials is of major importance in order to make sure that organs at risk are not overexposed. GATE provides all the capability needed to calculate dose profiles for internal dosimetry. The extrapolation of the dose for a human model is a first step towards clinical trials.
Source position measurement by Cherenkov emission imaging from applicators for high‐dose‐rate brachytherapy
Authors: Yogo Katsunori , Noguchi Yumiko , Okudaira Kuniyasu , Nozawa Marika , Ishiyama Hiromichi , Okamoto Hiroyuki , Yasuda Hiroshi , Oguchi Hiroshi , Yamamoto Seiichi 
Published: November 2020

PurposeWe developed a novel and simple method to measure the source positions in applicators directly for high‐dose‐rate (HDR) brachytherapy based on Cherenkov emission imaging, and evaluated the performance.MethodsThe light emission from plastic applicators used in cervical cancer treatments, irradiated by an 192Ir γ‐ray source, was captured using a charge‐coupled device camera. Moreover, we attached plastics of different shapes, including tapes, tubes, and plates to a metal applicator, to use as screens for the Cherenkov imaging. We determined the source positions and dwell intervals from the light profiles along with the applicator and compared these with preset values and dummy marker measurements.ResultsThe source positions and dwell intervals measured from the light images were comparable to the dummy marker measurements and preset values. The distance from the applicator tip to the first source positions agreed with the dummy marker measurements within 0.2 mm for the plastic tandem. The dwell intervals measured using the Cherenkov method agreed with the preset values within 0.6 mm. The distances measured with three plastic types on the metal applicator also agreed with the dummy marker measurements within 0.2 mm. The dwell intervals measured using the plastic tape agreed with the preset values within 0.7 mm.ConclusionsThe proposed method should be suitable for rapid and easy quality assurance (QA) investigations in HDR brachytherapy, as it enables source position using a single image. The method allows for real‐time, filmless measurements of the source positions to be obtained and is useful for rapid feedback in QA procedures.
Performance of a multileaf collimator system for a 1.5T MR‐linac
Authors: Zhang Ke , Tian Yuan , Li Minghui , Men Kuo , Dai Jianrong 
Published: November 2020

PurposeThe purpose of this study was to evaluate the performance of a multileaf collimator (MLC) system for the high magnetic field of the Elekta Unity magnetic resonance linear accelerator (MR‐linac).MethodsPerformance was evaluated as recommended in AAPM Report Nos. 72 and 142, and MLC motor radiofrequency (RF) shielding was also evaluated. Fields of 99.8 × 99.8 mm2 and 199.6 × 199.6 mm2 were examined to calculate the leaf width. Profiles of 28.4 × 28.4 mm2, 57.0 × 57.0 mm2, 99.8 × 99.8 mm2, and 199.6 × 199.6 mm2 fields at center and off‐axis positions were measured using a microDiamond detector and BEAMSCAN® MR water phantom to determine the field penumbra. EBT3 film was exposed to a 190.0 × 220.0 mm2 field composed of two strip segments to assess the tongue‐and‐groove (T&G) effect. Outputs of 100.0 × 100.0 mm2 open and blocked fields at center and off‐axis positions were measured using a PTW TW31021 ion chamber and a film with the full MLC‐blocked field to determine transmission. The minimum gap fields were also exposed on EBT3 film at center and off‐axis positions to assess leakage between leaf tips in the “closed” position. The picket fence test was performed using a megavoltage imager to analyze leaf positional reproducibility. RF shielding was measured via real‐time MR imaging of a homogeneous phantom and quantified using the signal‐to‐noise ratio (SNR).ResultsThe leaf widths were 7.00 ± 0.00 and 7.10 ± 0.00 mm for 99.8 × 99.8 and 199.6 × 199.6 mm2 fields, respectively. The leaf side penumbra ranged from 5.11 ± 0.08 to 11.28 ± 0.29 mm and the leaf tips penumbra ranged from 4.47 ± 0.03 to 6.25 ± 0.15 mm for the field size range of 28.4 × 28.4 mm2 to 199.6 × 199.6 mm2. The T&G effect resulted in an underdose of up to 23.41 ± 0.88%. The max leaf transmission was 0.33 ± 0.00% when MLCs were all closed and diaphragms were all opened, and this value was reduced to 0.18 ± 0.00% when the diaphragm blocked the field with a minimum MLC gap. The leaf tip leakage rates were 60.08 ± 0.05% at field center and 2.94 ± 0.00% approximately 100 mm off‐axis. At 6 months, the short‐term leaf position reproducibility was 0.11 mm (2σ), and the long‐term leaf position reproducibility was 0.19 mm (2σ). Leaf motion led to small fluctuations of the SNR of up to 1.64%.ConclusionThe new MLC system has a comparable T&G effect, low radiation leakage, high positioning reproducibility, and good RF shielding for the Elekta Unity MR‐linac. However, more attention is required for the positional change of the leaf side penumbra.
Deconvolution‐based distortion correction of EPI using analytic single‐voxel point‐spread functions
Authors: Patzig Franz , Mildner Toralf , Schlumm Torsten , Müller Roland , Möller Harald E. 
Published: November 2020

PurposeTo develop a postprocessing algorithm that corrects geometric distortions due to spatial variations of the static magnetic field amplitude, B0, and effects from relaxation during signal acquisition in EPI.Theory and MethodsAn analytic, complex point‐spread function is deduced for k‐space trajectories of EPI variants and applied to corresponding acquisitions in a resolution phantom and in human volunteers at 3 T. With the analytic point‐spread function and experimental maps of B0 (and, optionally, the effective transverse relaxation time, ) as input, a point‐spread function matrix operator is devised for distortion correction by a Thikonov‐regularized deconvolution in image space. The point‐spread function operator provides additional information for an appropriate correction of the signal intensity distribution. A previous image combination algorithm for acquisitions with opposite phase blip polarities is adapted to the proposed method to recover destructively interfering signal contributions.ResultsApplications of the proposed deconvolution‐based distortion correction (“DecoDisCo”) algorithm demonstrate excellent distortion corrections and superior performance regarding the recovery of an undistorted intensity distribution in comparison to a multifrequency reconstruction. Examples include full and partial Fourier standard EPI scans as well as double‐shot center‐out trajectories. Compared with other distortion‐correction approaches, DecoDisCo permits additional deblurring to obtain sharper images in cases of significant effects.ConclusionRobust distortion corrections in EPI acquisitions are feasible with high quality by regularized deconvolution with an analytic point‐spread function. The general algorithm, which is publicly released on GitHub, can be straightforwardly adapted for specific EPI variants or other acquisition schemes.
Efficient reliability analysis of slopes integrating the random field method and a Gaussian process regression‐based surrogate model
Authors: Zhu Bin , Hiraishi Tetsuya , Pei Huafu , Yang Qing 
Published: November 2020

AbstractEfficient evaluation of slope stability is a frontier in geo‐disaster prevention fields. While many slope stability evaluation methods, ranging from deterministic to probabilistic, have been proposed, reliability methods are particularly advantageous as they can account for uncertainties during slope stability evaluation. To address the problem of the low efficiency of direct Monte Carlo simulations and overcome the defects of the traditional response surface method, in this work, a novel probabilistic procedure that integrates a Gaussian process regression‐based surrogate model and the random limit equilibrium method for slope stability evaluation while accounting for the spatial variability of soil strength is proposed. The novel Gaussian process regression‐based surrogate model is efficiently used in the Monte Carlo simulation to reduce the number of calls for direct stability analysis of a slope with spatially varied soil strength. To verify the accuracy and efficiency of the proposed procedure, it was applied to three case studies: the first one is a slope in saturated clay under undrained conditions; the second one is a slope for which the friction angle and cohesion values are cross‐correlated; and the third one is a real slope with multiple soil layers. The results obtained from the comparisons with other methods confirmed the precision and feasibility of the proposed procedure.