bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fully automated segmentation of left ventricular scar from 3D late gadolinium enhancement magnetic resonance imaging using a cascaded multi‐planar U‐Net (CMPU‐Net)
Authors: Zabihollahy Fatemeh , Rajchl Martin , White James A. , Ukwatta Eranga 
Published: January 2020

PurposeThree‐dimensional (3D) late gadolinium enhancement magnetic resonance (LGE‐MR) imaging enables the quantification of myocardial scar at high resolution with unprecedented volumetric visualization. Automated segmentation of myocardial scar is critical for the potential clinical translation of this technique given the number of tomographic images acquired.MethodsIn this paper, we describe the development of cascaded multi‐planar U‐Net (CMPU‐Net) to efficiently segment the boundary of the left ventricle (LV) myocardium and scar from 3D LGE‐MR images. In this approach, two subnets, each containing three U‐Nets, were cascaded to first segment the LV myocardium and then segment the scar within the presegmented LV myocardium. The U‐Nets were trained separately using two‐dimensional (2D) slices extracted from axial, sagittal, and coronal slices of 3D LGE‐MR images. We used 3D LGE‐MR images from 34 subjects with chronic ischemic cardiomyopathy. The U‐Nets were trained using 8430 slices, extracted in three orthogonal directions from 18 images. In the testing phase, the outputs of U‐Nets of each subnet were combined using the majority voting system for final label prediction of each voxel in the image. The developed method was tested for accuracy by comparing its results to manual segmentations of LV myocardium and LV scar from 7250 slices extracted from 16 3D LGE‐MR images. Our method was also compared to numerous alternative methods based on machine learning, energy minimization, and intensity‐thresholds.ResultsOur algorithm reported a mean dice similarity coefficient (DSC), absolute volume difference (AVD), and Hausdorff distance (HD) of 85.14% ± 3.36%, 43.72 ± 27.18 cm3, and 19.21 ± 4.74 mm for determining the boundaries of LV myocardium from LGE‐MR images. Our method also yielded a mean DSC, AVD, and HD of 88.61% ± 2.54%, 9.33 ± 7.24 cm3, and 17.04 ± 9.93 mm for LV scar segmentation on the unobserved test dataset. Our method significantly outperformed the alternative techniques in segmentation accuracy (P < 0.05).ConclusionsThe CMPU‐Net method provided fully automated segmentation of LV scar from 3D LGE‐MR images and outperformed the alternative techniques.
Spatially guided nonlocal mean approach for denoising of PET images
Authors: Arabi Hossein , Zaidi Habib 
Published: January 2020

PurposeNonlocal mean (NLM) filtering proved to be an effective tool for noise reduction in natural and medical imaging. The technique relies on existing redundant information in the input image to discriminate the genuine signal from noise. However, due to the prohibitively long computation time, the search for finding similar information is confined by a predefined search window, which may hamper the performance of this filter. In this work, a spatially guided non local mean (SG‐NLM) approach was proposed to overcome this issue. The proposed method was evaluated on whole‐body positron emission tomography images presenting with high noise levels, which adversely affect lesion detectability and quantitative accuracy.MethodsIn the SG‐NLM method, as opposed to the conventional NLM method, where a predefined search window is defined to confine exhaustive search for finding similar patterns, the information about similar patterns is extracted from the clustered version (created based on signal intensity levels) of the input image as well as information about prominent edges. The performance of the SG‐NLM was evaluated against post‐reconstruction NLM, Gaussian, bilateral and BayesShrink Wavelet denoising approaches. A digital phantom containing three small inserts mimicking lesions in the lung, experimental study using the Jaszczak phantom and whole‐body PET/CT clinical studies were utilized to assess the performance of abovementioned denoising approaches.ResultsThe SG‐NLM method led to a signal‐to‐noise (SNR) increase from 21.3 (unfiltered PET image) to 30.1 in computer simulations of small lesions while the NLM mean filer resulted in an SNR of 29.4 (P < 0.05). The experimental Jaszczak phantom study demonstrated that the contrast‐to‐noise ratio (CNR) increased from 11.3 when using the Gaussian filter to 18.6 and 19.5 when using NLM and SG‐NLM filters (P < 0.05), respectively. The superior performance of the SG‐NLM approach was confirmed by clinical studies where the bias in malignant lesions decreased to −2.3 ± 1.1% compared to −11.7 ± 2.4 and −2.9 ± 1.1 achieved using the Gaussian and NLM methods (P < 0.05), respectively.ConclusionsThe proposed SG‐NLM achieves promising compromise between noise reduction and signal preservation compared to the conventional NLM method. The superior performance of the SG‐NLM method was accomplished without adding extra burden to the computational complexity of the conventional NLM filter, which makes it attractive for denoising PET images.
Experimental measurement of ionization chamber angular response and associated magnetic field correction factors in MR‐linac
Authors: Iakovenko Viktor , Keller Brian , Sahgal Arjun , Sarfehnia Arman 
Published: January 2020

PurposeTo measure ionization chamber dose response as a function of the angle between magnetic field direction and ionization chamber orientation in magnetic resonance‐guided radiation therapy (MRgRT) system, and to evaluate angular dependence of magnetic field correction factor for reference dosimetry.MethodsMeasurements were performed on an Elekta MR‐linac that integrates a 1.5‐T Philips MRI and a 7‐MV FFF photon beam accelerator. The response of four reference class chambers (Exradin‐A19, A1SL, IBA FC65‐G, and CC13, paired with a PTW UE electrometer) was studied. An in‐house built MR‐compatible water tank and an accompanying cylindrical insert that allowed chamber rotation around the cylinder's axis was used. The EPID onboard imaging was used to center chamber at the MR‐linac isocenter (143.5 cm, SAD), as well as to verify position at each datapoint.ResultsA clear angular dependence of dose response for all chambers has been measured. The most significant effect of magnetic field on relative chamber response in the presence of magnetic field was observed in the orientation when chamber axis is perpendicular to the direction of magnetic field with the tip pointing in the same direction as Lorentz force. This effect is more pronounced for larger volume chambers; the maximum relative variation in the chamber response (between the setup described above and the one where chamber and magnetic field are parallel) is a 5.3% and 4.6% increase for A19 and FC65‐G, respectively, and only 2.0% and 1.9% for smaller volume A1SL and CC13 chamber, respectively. We measured the absolute magnitude of the magnetic field correction factor for the Exradin‐A19, A1SL, IBA FC65‐G, and CC13 to be 0.938 ± 1.13%, 0.968 ± 0.99%, 0.950 ± 1.13%, and 0.975 ± 1.13%, respectively. The values are for perpendicular orientation of the chamber relative to magnetic field and parallel to the Lorentz force.ConclusionsExperimental measurements carried out in this study have verified the optimal orientation of ionization chamber in terms of minimizing effect of magnetic field on the chamber dose response. This study provides a detailed high‐resolution measurement of absolute values for four reference class chambers as a function of the angle between ionization chamber’s central axis and the direction of strong magnetic field over a full 360° rotation. The experimental results of this study can further be used for optimization of the actual sensitive volume of the chamber (and analysis of dead volume) in future Monte Carlo chamber simulations in the presence of strong magnetic fields. In addition, it will provide some necessary data for future reference dosimetry protocols for MR‐linac.
A fluence modulation and scatter shielding apparatus for dedicated breast CT: Theory of operation
Authors: Ghazi Peymon 
Published: January 2020

PurposeTo introduce an auxiliary apparatus of fluence modulation and scatter shielding for dedicated breast computed tomography (bCT) and the corresponding patient‐specific method of image acquisition.MethodsThe apparatus is composed of two assemblies, referred to herein as the “Dynamic Fluence Gate” (FG) and “Scatter Shield” (SS), that work in synchrony to form a narrow beam sweeping the entire fan angle coverage of the imaging system during a projection. The apparatus, as a whole, is referred to as FG‐SS. FG and SS are pre‐patient and post‐patient units, respectively. Each is composed of a rotating drum, on top of which are installed two sheets of high x‐ray attenuating material, a sensory system, and the constituent robotics. The sheets of each unit are positioned such that an opening — a window Fluence Modulation and Scatter Shielding is formed between them. The rotations of the drums and positioning of the sheets are synchronized and adjusted such that a line of sight is created between the source, FG window, the breast, and the SS window. With line of sight achieved, the narrow beam transitions from the source to the detector. The fluence of the narrow beam during a projection depends on the size, shape, and positioning of the breast. The FG‐SS method of imaging is discussed mathematically and demonstrated using computer simulations. A series of Monte Carlo simulations are conducted to evaluate the performance of the system as relates to its impact on the imager’s dynamic range, dose distribution to the breast, noise inhomogeneity in reconstructed images, and scatter buildup in projections within small, medium, and large breasts composed of homogeneous medium breast tissue.ResultsImplementation of FG‐SS results in near scatter‐free projections, reduction in both dose and the required dynamic range of the imager, and equalization of the quantum noise distribution in the reconstructed image. Using the disclosed design, the dynamic range was reduced by factors ranging from 1.6 to 5.5 across the range of breast sizes studied. A reduction in the acquisition of the scattered rays, varying between the factors of 6.1 (in the small breast) and 9.8 (in that large breast) was achieved and consequently, shading artifacts were suppressed. Noise in the CT image was equalized by reducing the overall spatial variation from 29% to <5% in small breast and from 45% to 14% in the large breast. An overall reduction in deposited dose to the breast was achieved — between 26% and 39% depending on the breast size.ConclusionsUtilization of the FG‐SS apparatus and technique was demonstrated via simulations to result in: significant reductions in dose to the breast, reductions in scatter uptake in projections, reduced required dynamic range of the imager, and homogenizing of quantum noise throughout the reconstructed image.
Influence of thermal oxidation and maleinized liquid polybutadiene on dynamic and static performance of short aramid fiber‐reinforced carbon black‐ethylene propylene diene monomer composites
Authors: Yang Bo , Li Peng , Luo Zhu , Zhong Jincheng , Yin Lianpeng 
Published: January 2020

AbstractShort aramid fiber (AF)‐reinforced rubber composites (SFRRs) possess better mechanical performance than carbon black‐filled rubber in many respects. However, the performance of an SFRR depends on interfacial adhesion to a large extent. In this article, AF was treated by thermal oxidation and then used to prepare AF‐reinforced carbon black‐ethylene propylene diene monomer (CB‐EPDM) composites in the presence of maleinized liquid polybutadiene rubber as the compatibilizer. The interfacial adhesion between the AF and matrix was evaluated by means of the relative debonding energy (RDE), and the corresponding dynamic and static performance was studied. The interfacial adhesion could be improved by a combination of fiber surface treatment and rubber compatibility, and the RDE was increased. Compared with those of the unmodified AF‐reinforced CB‐EPDM, the tensile moduli at 100% and 300% elongation and the tear strength increased by 27.4%, 16.7%, and 22.9%, respectively, and the stress‐controlled fatigue life of the notched sample increased by 140%. The results showed that the RDE decreased gradually with increasing average deformation after strain‐controlled fatigue for 30 000 cycles, and the RDE remained at a higher level in the AF‐reinforced CB‐EPDM when better interfacial adhesion was formed.
Metabolite variations and antioxidant activity of Muntingia calabura leaves in response to different drying methods and ethanol ratios elucidated by NMR‐based metabolomics
Authors: Zolkeflee Nur Khaleeda Zulaikha , Isamail Nor Amira , Maulidiani Maulidiani , Abdul Hamid Nur Ashikin , Ramli Nurul Shazini , Azlan Azrina , Abas Faridah 
Published: January 2020

AbstractIntroductionMuntingia calabura from the Muntingiaceae family has been documented for several medicinal uses. The combinations of drying treatment and extracting solvents for a plant species need to be determined and optimised to ensure that the extracts contain adequate amounts of the bioactive metabolites.ObjectiveEvaluate the metabolite variations and antioxidant activity among M. calabura leaves subjected to different drying methods and extracted with different ethanol ratios using proton nuclear magnetic resonance (1H‐NMR)‐based metabolomics.MethodologyThe antioxidant activity of M. calabura leaves dried with three different drying methods and extracted with three different ethanol ratios was determined by using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and nitric oxide (NO) scavenging assays. The metabolites variation among the extracts and correlation with antioxidant activity were analysed by 1H‐NMR‐based metabolomics.ResultsMuntingia calabura leaves extracted with 50% and 100% ethanol from air‐drying and freeze‐drying methods had the highest total phenolic content and the lowest IC50 value for the DPPH scavenging activity. Meanwhile, oven‐dried leaves extracted with 100% ethanol had the lowest IC50 value for the NO scavenging activity. A total of 43 metabolites, including sugars, organic acids, amino acids, phytosterols, phenolics and terpene glycoside were tentatively identified. A noticeable discrimination was observed in the different ethanol ratios by the principal component analysis. The partial least‐squares analysis suggested that 32 compounds out of 43 compounds identified were the contributors to the bioactivities.ConclusionThe results established set the preliminary steps towards developing this plant into a high value product for phytomedicinal preparations.
System optimisation quantitative model of on‐line NIR: a case of Glycyrrhiza uralensis Fisch extraction process
Authors: Zeng Jingqi , Zhou Zheng , Liao Yuan , Ma Lijuan , Huang Xingguo , Zhang Jing , Lin Ling , Zhu Jinyuan , Lei Leting , Cao Junjie , Shen Haoran , Zheng Yanfei , Wu Zhisheng 
Published: January 2020

AbstractIntroductionThe on‐line analysis of active pharmaceutical ingredients (APIs) during the extraction process in herbal medicine is a challenge. Establishing a reliable and robust model is a critical procedure for the industrial application of on‐line near‐infrared (NIR) technology.ObjectiveTo evaluate the advantages of on‐line NIR model development using system optimisation strategy, Glycyrrhiza uralensis Fisch was used as a case. The content of liquiritin and glycyrrhizic acid was monitored during pilot scale extraction process of Glycyrrhiza uralensis Fisch in three batches.MethodsHigh‐performance liquid chromatography (HPLC) was used as reference method for content determination of liquiritin and glycyrrhizic acid. The quantitative models of on‐line NIR were developed by system optimisation of processing trajectory. For comparison, the models were simultaneously developed by stepwise optimisation. Moreover, the modelling parameters obtained through system optimisation and stepwise optimisation were reused in three batches. Root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) were used to assess the model quality.ResultsThe average values of RMSEP and RPD of systematic model for liquiritin in three batches were 0.0361, 4.1525 (first batch), 0.0348, 4.7286 (second batch) and 0.0311, 4.9686 (third batch), respectively. In addition, the modelling parameters of systematic model for glycyrrhizic acid in three batches were same, and the average values of RMSEP and RPD were 0.0665 and 5.2751, respectively. The predictive performance and robustness of systematic models for the three batches were better than the comparison models.ConclusionThe work demonstrated that system optimisation quantitative model of on‐line NIR could be used to determine the contents of liquiritin and glycyrrhizic acid during Glycyrrhiza uralensis Fisch extraction process.
Aspirin for prevention of preeclampsia and fetal growth restriction
Authors: Loussert Lola , Vidal Fabien , Parant Olivier , Hamdi Safouane M. , Vayssiere Christophe , Guerby Paul 
Published: January 2020

AbstractFor the past decades, growing attention has been given to aspirin use during pregnancy. It favors placentation by its proangiogenic, antithrombotic, and anti‐inflammatory effects. Therefore, low doses of aspirin are prescribed in the prevention of placenta‐mediated complications, mainly preeclampsia and fetal growth restriction. However, questions regarding its clinical application are still debated. Aspirin is effective in preventing preeclampsia in a high‐risk population. Most guidelines recommend that risk stratification should rely on medical history. Nevertheless, screening performances dramatically improve if biochemical and biophysical markers are included. Concerning the appropriate timing and dose, latest studies suggest aspirin should be started before 16 weeks of pregnancy and at a daily dose of 100 mg or more. Further studies are needed to improve the identification of patients likely to benefit from prophylactic aspirin. Besides, the role of aspirin in the prevention of fetal growth restriction is still questioned.
Prenatal diagnosis of birth defects and termination of pregnancy in Hunan Province, China
Authors: Xie Donghua , Liang Changbiao , Xiang Yueyun , Wang Aihua , Xiong Lili , Kong Fanjuan , Li Haoxian , Liu Zhiyu , Wang Hua 
Published: January 2020

AbstractObjectiveThe aim of this study was to analyse the characteristics of the prenatal diagnosis (PD) of birth defects (BDs) and termination of pregnancy (TOP) for fetal anomalies and to suggest perinatal management.MethodsBD surveillance data were collected from 52 registered hospitals in Hunan between 2015 and 2018. The PD and TOP rates of BDs were calculated to examine the associations between infant sex, maternal age, and region.ResultsFrom 2015 to 2018, a total of 18 931 fetuses with BDs were identified, of which 10 299 fetuses (54.4%) were diagnosed prenatally and 9343 pregnancies (90.7% among PDs and 49.3% among BDs) were terminated. The mean gestational age at diagnosis for fetuses with BDs was 25.1 ± 5.9 weeks and showed a downward trend over the study period. The average PD rate of the BDs was higher in rural areas than in urban areas (58.1% vs 50.3%), higher for female than male fetuses (57.25% vs 48.92%), and higher for mothers older than age 35 than for those younger (58.62% vs 53.69%). The average TOP rate of fetuses with BDs in rural areas was higher than that in urban areas (91.99% vs 89.12%) and decreased with increasing maternal age ( = 7.926, P = .005). The five BDs with the highest PD rates were conjoined twins (100%), anencephaly (97.87%), congenital hydrocephalus (97.66%), chromosomal malformation (96.07%), and encephalocele (95.54%). The five BDs with the highest TOP rates among the PDs were conjoined twins (100%), exstrophy of the urinary bladder (100%), chromosomal malformation (98.09%), encephalocele (98%), and anencephaly (97.28%).ConclusionsMore than half of BDs were diagnosed prenatally, with the majority diagnosed at less than 28 gestational weeks. The TOP rates following PD in Hunan Province were high, especially for rural and younger mothers. The findings suggest a need for high‐quality, targeted counselling following PD.
Prenatal ultrasound findings of holoprosencephaly spectrum: Unusual associations
Authors: El‐Dessouky Sara H. , Aboulghar Mona M. , Gaafar Hassan M. , Abdella Rana M. , Sharaf Marwa F. , Ateya Mohamed I. , Elarab Ahmed Ezz , Zidan Walaa H. , Helal Rania M. , Aboelsaud Samah M. , Eid Maha M. , Abdel‐Salam Ghada M.H. 
Published: January 2020

AbstractObjectiveThe objective of this study is to evaluate the prenatal diagnosis, postnatal characteristics, and the spectrum of associated findings in fetuses with holoprosencephaly (HPE).MethodsFetal neurosonograms, postnatal assessment, and chromosomal analysis were performed in a cohort of 25 fetuses with HPE.ResultsThe prevalence of HPE in high‐risk pregnancies was 4.4:10 000. The alobar subtype was the most frequently encountered, with 17 cases (68%). Interestingly, among them, four cases (16%) presented with the rare agnathia‐otocephaly complex. Chromosomal abnormalities were detected in 11 cases (44%), the most frequent being trisomy 13 in seven cases (five alobar, one semilobar, and one lobar HPE), followed by trisomy 18 in two cases with semilobar HPE. One case of alobar HPE had 45, XX, t(18;22) (q10;q10), −18p karyotyping, and one case of semilobar HPE was associated with triploidy. Facial malformations in HPE spectrum ranged from cyclopia, proboscis, and arrhinia that were associated with the alobar subtype to hypotelorism and median cleft that were frequent among the semilobar and lobar subtypes. Associated neural tube defects were identified in 12% of cases.ConclusionOur study illustrates the clinical and genetic heterogeneity of HPE and describes different chromosomal abnormalities associated with HPE.
Graphite fluoride and fluorographene as a new class of solid lubricant additives for high‐performance polyamide 66 composites with excellent mechanical and tribological properties
Authors: Sun Haoyang , Li Tao , Lei Fan , Yang Meng , Li Dandan , Huang Xianhang , Sun Dazhi 
Published: January 2020

AbstractFluorographene (FG) with layer numbers of 3–4 was successfully prepared through facile microwave‐assisted liquid phase exfoliation of raw graphite fluoride (GrF). The raw GrF and the as‐prepared FG were then directly incorporated into polyamide 66 (PA66) by melt processing without using any surfactants. Microstructural, mechanical and tribological properties of the prepared PA66 composites were investigated. Various characterization results showed that both GrF and FG, as novel solid lubricants, can effectively improve the mechanical and anti‐wear performances of the PA66 matrix. It was also found that FG is better at improving mechanical properties and reducing the friction of PA66 than GrF at low concentrations owing to the large surface–volume ratio. The addition of 0.5 wt% FG into PA66 exhibits a ca 13% increase in tensile modulus, ca 5% increase in tensile strength, ca 18% reduction in coefficient of friction (COF) and ca 43% reduction in wear rate. However, at relatively high concentrations, such as 1.0 wt%, GrF shows a better reinforcement effect than FG owing to a uniform dispersion of GrF in the PA66 matrix. The addition of 1.0 wt% GrF into PA66 exhibits a ca 18% increase in tensile modulus, ca 5% increase in tensile strength, ca 37% reduction in COF and ca 46% reduction in wear rate. Wear tests also show that the excellent wear resistance of the PA66 composites is due to the improved mechanical properties and the lubrication of GrF and FG between the worn surfaces. Our current work demonstrates the tremendous potentials of fluorinated carbon materials for enhancing mechanical and anti‐wear properties of polymeric materials. © 2020 Society of Chemical Industry