bluuebunny/crossref_metadata_2025 huggingface dataset:
Update on the role of emerging stem cell technology in head and neck medicine
Authors: Spencer Harry , Moshkbouymatin Navid , Webb William Richard , Joshi Anil , D'Souza Alwyn
Published: March 2021

Head and neck surgery is a broad discipline that involves the management of complex conditions such as burns, skin cancer, head and neck cancer, congenital abnormalities, and facial rejuvenation. For patients with cancer, surgery, radiotherapy, and chemotherapy are often the main modes of treatment. Many patients require follow‐up reconstructive surgery, and the use of stem cells offers novel treatments that could aid recovery. Laryngeal, tracheal, and neuronal tissues are frequently damaged by surgery in the head and neck and these tissues have little intrinsic regenerative ability. Pluripotent embryonic stem cells retain the ability to differentiate into a wide variety of cells meaning that large tissue defects can be reduced by stimulating new cell growth. Research has demonstrated potential benefits of using stem cells in facial rejuvenation procedures and the management of burns sequelae. The advancements made in the use of adult progenitor stem cells as a possible source for pluripotent stem cells (induced pluripotent stem cells) mean that ethical considerations around the use of embryological tissue can be minimized, allowing for more research to take place. Currently, the evidence base for the use of stem cells in head and neck surgery is limited, but it has now been proven that stem cells can act as a source for lost or damaged tissue in the head and neck. With continuous advancements being made in the fields of tissue engineering, it is likely that stem cells will play a major role in head and neck surgery in the future.
Seven‐year‐olds' references to internal states when playing with toy figures and a video game
Authors: Hashmi Salim , Paine Amy L. , Hay Dale F.
Published: March 2021

References to internal states (e.g., thoughts, feelings, and desires) indicate children's appreciation of people's inner worlds. Many children spend time playing video games; however, the nature of children's speech when doing so has received little attention. We investigated the use of internal state language (ISL) as 251 seven‐year‐olds played with toy figures and a video game designed for the study. Although children used ISL more when playing with toy figures, children used ISL in both contexts, highlighting video game play as a context where children demonstrate their appreciation of inner worlds. Children's speech in the two contexts differed in how ISL was used: references to children's own internal states were more common when playing the video game, and the characters' internal states more common when playing with the toy figures. These findings are discussed with reference to the format of the play activities affording different opportunities to discuss internal states.

Highlights

In traditional play children refer to internal states, however, it is unclear whether this occurs when they play video games.

Children referred to internal states when playing with toy figures and a video game, but did so more with the toys.

Children's video game play can be used as a new context for the study of children's social understanding.
Strategic resources for assessing PFAS ecological risks at AFFF sites
Authors: Conder Jason , Zodrow Jeanmarie , Arblaster Jennifer , Kelly Barry , Gobas Frank , Suski Jamie , Osborn Erin , Frenchmeyer Meredith , Divine Craig , Leeson Andrea
Published: March 2021

The use of aqueous film forming foam (AFFF) in the United States has caused concern about the potential effects of per- and polyfluoroalkyl substances (PFAS) on ecological resources. Moreover, the limited availability of scientific information and a lack of guidance have collectively resulted in significant challenges for ecological risk assessors supporting site-specific investigations and management decisions at PFAS-impacted sites. To address these needs, the environmental science and technology program of the Department of Defense (DoD), the Strategic Environmental Research and Development Program (SERDP), began funding four desktop review projects in 2018. Project teams were tasked with developing strategic guidance for assessing ecological risk at AFFF-impacted DoD sites. The projects focused specifically on ecological risk assessment practices for threatened and endangered (T&E) species; however, the recommendations and approaches presented in the projects are also applicable and adaptable to common species. The present review provides risk assessors and site managers an overview of how the resources provided in these projects can support ecological-risk-based management decisions at AFFF and other PFAS-impacted sites. Additionally, we synthesize perspectives offered by the four projects on a path forward for PFAS ecological risk assessment, including research needs that we recommend should be prioritized by the scientific community. Integr Environ Assess Manag 2021;17:746–752. © 2021 SETAC

KEY POINTS

Aqueous film forming foam (AFFF) use has resulted in concern regarding potential ecological risks associated with per- and polyfluoroalkyl substances (PFAS), and a lack of guidance has resulted in significant challenge for site-specific investigations and management decisions at AFFF sites. The Strategic Environmental Research and Development Program (SERDP) began funding four desktop review projects in 2018 to develop strategic guidances for assessing ecological risk at AFFF-impacted sites. This review provides risk assessors and site managers an overview of how the resources provided in these projects can support ecological risk-based management decisions at AFFF and other PFAS-impacted sites. The review also highlights key research needs that, if addressed, will aid in improving site-specific ecological risk assessments for PFAS at AFFF sites.
An improved framework for polyp image segmentation based on SegNet architecture
Authors: Afify Heba M. , Mohammed Kamel K. , Hassanien Aboul Ella
Published: March 2021

A polyp is one of the major causes of gastroenterology, which leads to colorectal cancer. The detection of polyps by colonoscopy imaging is a significant challenge because of the diversity in polyp structure and lack of examination accuracy. To solve this problem, the automatic segmentation of polyps can be used to enhance examination accuracy and reduce gastrointestinal (GI) disease. In this paper, the framework of polyp image segmentation is developed by a deep learning approach, especially a convolutional neural network. This proposed framework used the Kvasir‐SEG database, which contains 1000 GI polyp images and corresponding segmentation masks according to annotation by medical experts. This database is divided into 900 for training images and 100 for testing images. This framework is based on image preprocessing and two types of SegNet architecture to obtain the segmented polyp image. This paper has demonstrated state‐of‐the‐art performance on both VGG‐16, and VGG‐19 networks for training and testing data to address colorectal cancer screening rates. The results confirmed that the VGG‐19 model has outperformed the VGG‐16 model via all evaluation parameters except sensitivity for the polyp segmentation on the Kvasir‐SEG dataset. Additionally, it will support gastroenterologists during medical strategy to correctly choose the treatment with less time.
Homocysteine induced a calcium‐mediated disruption of mitochondrial function and dynamics in endothelial cells
Authors: Chen Li‐ting , Xu Ting‐ting , Qiu Ya‐qing , Liu Nuo‐ya , Ke Xin‐yu , Fang Lu , Yan Jie‐ping , Zhu Dan‐yan
Published: March 2021

Homocysteine (Hcy) is a sulfur‐containing amino acid that originated in methionine metabolism and the elevated level of Hcy in plasma is considered to be an independent risk factor for cardiovascular diseases (CVD). Endothelial dysfunction plays a major role in the development of CVD, while the potential mechanism of Hcy‐induced endothelial dysfunction is still unclear. Here, in Hcy‐treated endothelial cells, we observed the destruction of mitochondrial morphology and the decline of mitochondrial membrane potential. Meanwhile, the level of ATP was reduced and the reactive oxygen species was increased. The expressions of dynamin‐related protein 1 (Drp1) and phosphate‐Drp1 (Ser616) were upregulated, whereas the expression of mitofusin 2 was inhibited by Hcy treatment. These findings suggested that Hcy not only triggered mitochondrial dysfunction but also incurred an imbalance of mitochondrial dynamics in endothelial cells. The expression of mitochondrial calcium uniporter (MCU) was activated by Hcy, contributing to calcium transferring into mitochondria. Interestingly, the formation of mitochondria‐associated membranes (MAMs) was increased in endothelial cells after Hcy administration. The inositol 1,4,5‐triphosphate receptor (IP3R)–glucose‐regulated protein 75 (Grp75)–voltage‐dependent anion channel (VDAC) complex, which was enriched in MAMs, was also increased. The accumulation of mitochondrial calcium could be blocked by inhibiting with the IP3R inhibitor Xestospongin C (XeC) in Hcy‐treated cells. Then, we confirmed that the mitochondrial dysfunction and the increased mitochondrial fission induced by Hcy could be attenuated after Hcy and XeC co‐treatment. In conclusion, Hcy‐induced mitochondrial dysfunction and dynamics disorder in endothelial cells were mainly related to the increase of calcium as a result of the upregulated expressions of the MCU and the IP3R–Grp75–VDAC complex in MAMs.
Nephroprotective effect of Emblica officinalis fruit extract against malachite green toxicity in piscine model: Ultrastructure and oxidative stress study
Authors: Sinha Reshma , Jindal Rajinder , Faggio Caterina
Published: March 2021

Malachite green (MG) is a multi‐application dye with raised concern as aquatic toxicant. Cyprinus carpio fingerlings were exposed to MG and simultaneously fed with Emblica officinalis (EO) fruit extract to mitigate the MG induced nephrotoxicity. MG exposure developed depressed activity of antioxidant enzymes such as catalase, superoxide dismutase, glutathione‐s‐transferase, and reduced glutathione, while levels of malondialdehyde got significantly (p < .05) elevated after 60 days MG exposure. H&E staining revealed increased intracellular space, vacuolation, fluid‐filled spaces, damaged brush border lining of proximal convoluted tubule (PCT), focal necrosis, nuclear transformations and shrunken glomerulus. Further, Transmission electron microscope study detailed structural cytotoxicity with the appearance of the heterochromatic nucleus, electron‐dense lysosomal bodies, damaged brush border lining of PCT, and necrosis; glomerulus exhibited erythrocyte infiltration and fused pedicels of podocyte. While, EO extract supplemented diet culminated in the restoration of the renal cytoarchitecture and significantly (p < .05) enhanced activity of antioxidant enzymes.
The next‐generation coronavirus diagnostic techniques with particular emphasis on the SARS‐CoV‐2
Authors: Hemida Maged G.
Published: March 2021

The potential zoonotic coronaviruses (SARS‐CoV, MERS‐CoV, and SARS‐CoV‐2) are of global health concerns. Early diagnosis is the milestone in their mitigation, control, and eradication. Many diagnostic techniques are showing great success and have many advantages, such as the rapid turnover of the results, high accuracy, and high specificity and sensitivity. However, some of these techniques have several pitfalls if samples were not collected, processed, and transported in the standard ways and if these techniques were not practiced with extreme caution and precision. This may lead to false‐negative/positive results. This may affect the downstream management of the affected cases. These techniques require regular fine‐tuning, upgrading, and optimization. The continuous evolution of new strains and viruses belong to the coronaviruses is hampering the success of many classical techniques. There are urgent needs for next generations of coronaviruses diagnostic assays that overcome these pitfalls. This new generation of diagnostic tests should be able to do simultaneous, multiplex, and high‐throughput detection of various coronavirus in one reaction. Furthermore, the development of novel assays and techniques that enable the in situ detection of the virus on the environmental samples, especially air, water, and surfaces, should be given considerable attention in the future. These approaches will have a substantial positive impact on the mitigation and eradication of coronaviruses, including the current SARS‐CoV‐2 pandemic.
Design of a multi‐octave power amplifier using broadband load‐pull X‐parameters
Authors: Wu Meilin , Cai Jialin , King Justin , Chen Shichang , Su Jiangtao , Cao Wenhui
Published: March 2021

The design of a multi‐octave power amplifier (PA) based on a broadband load‐pull X‐parameter model is described for the first time in this work. A 10‐W GaN package transistor is employed for model X‐parameter model extraction. Once the model is extracted, it is compared with the equivalent circuit model provided from the device manufacturer, and it is found that the X‐parameter model accuracy is comparable to that of the original circuit model. In particular, the X‐parameter model can accurately determine the areas of the load Smith chart leading to optimal output power and drain efficiency, essential considerations for extracting maximum device performance. A Chebyshev low‐pass architecture is utilized for both the input and the output matching network designs. Finally, a multi‐octave bandwidth PA, from 0.6 to 2.3 GHz, is designed. Simulation results of the broadband X‐parameter model and the measured results of the realized PA are compared, with a high fidelity match evident, thus demonstrating the efficacy of the design procedure of multi‐octave PA with broadband X‐parameters. The output power of the realized PA across the operating frequency band remains between 39.51 and 42.41 dBm, while the drain efficiency remains above 60%, reaching as high as 73% around 2 GHz. The gain of the PA is greater than 11 dB over the complete frequency band.
Subchondral bone microarchitecture and mineral density in human osteoarthritis and osteoporosis: A regional and compartmental analysis
Authors: Li Yunfei , Liem Yulia , Dall'Ara Enrico , Sullivan Niall , Ahmed Haroon , Blom Ashley , Sharif Mohammed
Published: March 2021

Osteoarthritis (OA) and osteoporosis (OP) are historically considered to be inversely correlated but there may be an overlap between the pathophysiology of the two diseases. This study aimed to investigate the subchondral bone microarchitecture and matrix mineralization, and the association between them in OA and OP in relation to the degree of cartilage degeneration. Fifty‐six osteochondral plugs were collected from 16 OA femoral heads. They were graded on a regional basis according to the stages of cartilage degeneration, as evaluated by a new macroscopic and a modified microscopic grading system. Twenty‐one plugs were collected from seven femoral heads with OP. Plugs were scanned by microcomputed tomography and the microarchitectural and mineral properties were obtained for both subchondral plate and trabecular bone. Microarchitecture and material and apparent densities of subchondral bone in OP were similar to regions with early cartilage degeneration but different from regions with advanced cartilage degradation in OA femoral heads. Subchondral trabecular bone was more mineralized than subchondral plate in both OP and OA, and this compartmental difference varied by severity of cartilage degradation. Furthermore, the relationship among trabecular bone volume fraction, tissue mineral density, and apparent bone density was similar in OP and different stages of OA. Subchondral bone microarchitecture and mineral properties in OP are different from OA in a regionalized manner in relation to stages of cartilage degeneration. Both regional and compartmental differences at structural, material, and cellular levels need to be studied to understand the transition of OA subchondral bone from being osteoporotic to sclerotic.
MEK inhibition preferentially suppresses anchorage‐independent growth in osteosarcoma cells and decreases tumors in vivo
Authors: Shimizu Takatsune , Kimura Kiyomi , Sugihara Eiji , Yamaguchi‐Iwai Sayaka , Nobusue Hiroyuki , Sampetrean Oltea , Otsuki Yuji , Fukuchi Yumi , Saitoh Kaori , Kato Keiko , Soga Tomoyoshi , Muto Akihiro , Saya Hideyuki
Published: March 2021

Osteosarcoma is the most common high‐grade malignancy of bone, and novel therapeutic options are urgently required. Previously, we developed mouse osteosarcoma AXT cells that can proliferate both under adherent and nonadherent conditions. Based on metabolite levels, nonadherent conditions were more similar to the in vivo environment than adherent conditions. A drug screen identified MEK inhibitors, including trametinib, that preferentially decreased the viability of nonadherent AXT cells. Trametinib inhibited the cell cycle and induced apoptosis in AXT cells, and both effects were stronger under nonadherent conditions. Trametinib also potently decreased viability in U2OS cells, but its effects were less prominent in MG63 or Saos2 cells. By contrast, MG63 and Saos2 cells were more sensitive to PI3K inhibition than AXT or U2OS cells. Notably, the combination of MAPK/ERK kinase (MEK) and PI3K inhibition synergistically decreased viability in U2OS and AXT cells, but this effect was less pronounced in MG63 or Saos2 cells. Therefore, signal dependence for cell survival and crosstalk between MEK–ERK and PI3K–AKT pathways in osteosarcoma are cell context‐dependent. The activation status of other kinases including CREB varied in a cell context‐dependent manner, which might determine the response to MEK inhibition. A single dose of trametinib was sufficient to decrease the size of the primary tumor and circulating tumor cells in vivo. Moreover, combined administration of trametinib and rapamycin or conventional anticancer drugs further increased antitumor activity. Thus, given optimal biomarkers for predicting its effects, trametinib holds therapeutic potential for the treatment of osteosarcoma.
Using archaeological data and sediment parameters to review the formation of the Gravettian layers at Krems‐Wachtberg
Authors: Händel Marc , Thomas Roswitha , Sprafke Tobias , Schulte Philipp , Brandl Michael , Simon Ulrich , Einwögerer Thomas
Published: March 2021

The Gravettian site Krems‐Wachtberg in northeast Austria produced a wealth of archaeological and sedimentary data. Precondition for a detailed study of the formation processes is co‐occurrence of find layers with in situ and redeposited material. We use archaeological data and sediment parameters to review and refine a formation model that was based solely on field observations. The archaeological perspective relies upon the rich chipped stone assemblage where each artefact is attributed with 3D position, orientation, stratigraphy, typo‐technological description, and raw material determination. This enabled systematic refitting and 3D analyses of the results. High‐resolution sampling of the sediment sequence which was conducted in six columns at different locations of the excavated area provided comparable results for grain size, colour and carbonate content. The study illustrates the complementary benefits of field observations, archaeological data and sediment parameters. While detailed loess stratigraphy creates the frame for understanding palaeoenvironmental processes, archaeological data enhances visibility of local post‐occupational sedimentary processes. This allows the archaeological sequence to be placed into a cycle of gradual de‐ and restabilisation of the palaeosurface. Burial of the ~31k cal abp occupation layer occurred by solifluction, slope wash and aeolian deposition between two stable phases marked by tundra gley soils.
The impact of COVID‐19 on the technology sector: The case of TATA Consultancy Services
Authors: Ntasis Lazaros , Koronios Konstantinos , Pappas Theodoros
Published: March 2021

Two of the most unpredictable uncertainty indices could explain the business and stock price performance of TATA Consultancy Services (TCS) before and after the COVID‐19 pandemic. This pandemic affects business performance and predictability from uncertainty indices. With the second spread of the pandemic, IT industries have been prepared for the high networking bandwidth. Moreover, the bivariate VAR(1)‐GARCH(1,1) model is weaker during the COVID‐19 period. IT outsourcing after the worldwide outbreak of the disease is one of the most thriving enterprises globally. The coronavirus crisis is expected to have an impact on the IT outsourcing industry. Most of the uncertainty indices of these days are built up from news outlets explored in the case study of TCS. Quantitative examination strategies have been utilized to explore the impact of doubt indices in TCS and the residuals if the organization's emergency persists.
Liver Fat Assessment in Multiview Sonography Using Transfer Learning With Convolutional Neural Networks
Authors: Byra Michal , Han Aiguo , Boehringer Andrew S. , Zhang Yingzhen N. , O'Brien William D. , Erdman John W. , Loomba Rohit , Sirlin Claude B. , Andre Michael
Published: March 2021

Objectives

To develop and evaluate deep learning models devised for liver fat assessment based on ultrasound (US) images acquired from four different liver views: transverse plane (hepatic veins at the confluence with the inferior vena cava, right portal vein, right posterior portal vein) and sagittal plane (liver/kidney).

Methods

US images (four separate views) were acquired from 135 participants with known or suspected nonalcoholic fatty liver disease. Proton density fat fraction (PDFF) values derived from chemical shift‐encoded magnetic resonance imaging served as ground truth. Transfer learning with a deep convolutional neural network (CNN) was applied to develop models for diagnosis of fatty liver (PDFF ≥ 5%), diagnosis of advanced steatosis (PDFF ≥ 10%), and PDFF quantification for each liver view separately. In addition, an ensemble model based on all four liver view models was investigated. Diagnostic performance was assessed using the area under the receiver operating characteristics curve (AUC), and quantification was assessed using the Spearman correlation coefficient (SCC).

Results

The most accurate single view was the right posterior portal vein, with an SCC of 0.78 for quantifying PDFF and AUC values of 0.90 (PDFF ≥ 5%) and 0.79 (PDFF ≥ 10%). The ensemble of models achieved an SCC of 0.81 and AUCs of 0.91 (PDFF ≥ 5%) and 0.86 (PDFF ≥ 10%).

Conclusion

Deep learning‐based analysis of US images from different liver views can help assess liver fat.
Point‐of‐Care Ultrasound Pronator Quadratus Hematoma Sign for Detection of Clinically Non‐Angulated Pediatric Distal Forearm Fractures
Authors: Snelling Peter J. , Keijzers Gerben , Ware Robert S.
Published: March 2021

Objectives

Point‐of‐care ultrasound (POCUS) diagnosis of distal forearm fractures relies on the identification of buckling or breach of hyperechoic bone cortex. We describe the pronator quadratus hematoma (PQH) formation visualized on POCUS, the PQH sign, as it may aid diagnosis of pediatric distal forearm cortical breach fractures.

Methods

A prospective cohort of children presenting to an emergency department with isolated, clinically non‐angulated distal forearm injuries received POCUS by an expert emergency physician sonologist who identified the presence or absence of the PQH sign. They secondarily recorded the difference between the size of the pronator quadratus (PQ) muscle on both the affected and non‐affected forearms (PQ delta thickness). Children received an x‐ray subsequent to POCUS and were diagnosed based on an x‐ray reported by a radiologist masked to POCUS findings.

Results

Thirty‐eight children were recruited. All 22 patients with cortical breach fracture had PQH sign present (100%; 95%CI: 85–100%), while all 16 patients without cortical breach fracture had PQH sign absent (100%; 95%CI: 79–100%). PQ delta thickness ranged from 2.1 to 10.2 mm in cortical breach fractures, 0.0 to 1.1 mm in buckle fractures, and 0.2 to 0.8 mm in patients without fracture.

Conclusions

The PQH sign correctly distinguished all children with, and without, cortical breach fractures. All PQ delta thicknesses were ≧2.1 mm when cortical breach fracture was present and ≦1.1 mm when cortical breach fracture was absent. The PQH sign and PQ delta thickness are promising measurements to identify pediatric distal forearm cortical breach fractures, and their utility should be confirmed in larger studies with sonologists of different abilities.
High‐throughput NGS‐based genotyping and phenotyping: Role in genomics‐assisted breeding for soybean improvement
Authors: Bhat Javaid Akhter , Yu Deyue
Published: March 2021

Soybean is an important food crop that provides edible protein and oil for human and animal nutrition. Conventional phenotypic‐based breeding approaches have made significant contribution in the last century by developing many improved soybean varieties. However, due to the longer time taken to develop a variety, low genetic gain per unit time, and adverse environmental influence of phenotypic‐based selection, conventional approaches are not sufficient to maintain pace with growing population and climate change. In this context, the recent method of genotypic selection, that is, genomics‐assisted breeding (GAB) is considered a promising approach to address the challenges in soybean breeding. However, to harness the true potential of GAB in soybean improvement, the great coverage and precision in the genotyping and phenotyping are required. Previously, a huge gap was observed between the discovery and practical use of quantitative trait loci (QTLs) in soybean improvement. It has been suggested that low marker density and manually collected phenotypes are the major reasons for this failure. Hence, high‐throughput genotyping (HTG) providing higher genome‐wide marker density, as well as accurate and precise phenotyping using high‐throughput digital phenotyping (HTP) platforms, can significantly increase the success of QTL and candidate gene identification in soybean. These approaches can greatly increase the practical utility of GAB in soybean and also offer a faster characterization of germplasm and breeding materials. This review provides the detailed information on how the recent innovations in genomics and phenomics can assists in improving the efficiency and potential of GAB in soybean improvement.
Longitudinal Changes in Neuromelanin MRI Signal in Parkinson's Disease: A Progression Marker
Authors: Gaurav Rahul , Yahia‐Cherif Lydia , Pyatigorskaya Nadya , Mangone Graziella , Biondetti Emma , Valabrègue Romain , Ewenczyk Claire , Hutchison R. Matthew , Cedarbaum Jesse M. , Corvol Jean‐Christophe , Vidailhet Marie , Lehéricy Stéphane
Published: March 2021

Background

Development of reliable and accurate imaging biomarkers of dopaminergic cell neurodegeneration is necessary to facilitate therapeutic drug trials in Parkinson's disease (PD). Neuromelanin‐sensitive MRI techniques have been effective in detecting neurodegeneration in the substantia nigra pars compacta (SNpc). The objective of the current study was to investigate longitudinal neuromelanin signal changes in the SNpc in PD patients.

Methods

In this prospective, longitudinal, observational case–control study, we included 140 PD patients and 64 healthy volunteers divided into 2 cohorts. Cohort I included 99 early PD patients (disease duration, 1.5 ± 1.0 years) and 41 healthy volunteers analyzed at baseline (V1), where 79 PD patients and 32 healthy volunteers were rescanned after 2.0 ± 0.2 years of follow‐up (V2). Cohort II included 41 progressing PD patients (disease duration, 9.3 ± 3.7 years) and 23 healthy volunteers at V1, where 30 PD patients were rescanned after 2.4 ± 0.5 years of follow‐up. Subjects were scanned at 3 T MRI using 3‐dimensional T1‐weighted and neuromelanin‐sensitive imaging. Regions of interest were delineated manually to calculate SN volumes, volumes corrected by total intracranial volume, signal‐to‐noise ratio, and contrast‐to‐noise ratio.

Results

Results showed (1) significant reduction in volume and volume corrected by total intracranial volume between visits, greater in progressing PD than nonsignificant changes in healthy volunteers; (2) no significant effects of visit for signal intensity (signal‐to‐noise ratio); (3) significant interaction in volume between group and visit; (4) greater volume corrected by total intracranial volume at baseline in female patients and greater decrease in volume and increase in the contrast‐to‐noise ratio in progressing female PD patients compared with male patients; and (5) correlations between neuromelanin SN changes and disease severity and duration.

Conclusions

We observed a progressive and measurable decrease in neuromelanin‐based SN signal and volume in PD, which might allow a direct noninvasive assessment of progression of SN loss and could represent a target biomarker for disease‐modifying treatments. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
Effective diagnostic model construction based on discriminative breast ultrasound image regions using deep feature extraction
Authors: Yu Hailong , Sun Hang , Li Jing , Shi Liying , Bao Nan , Li Hong , Qian Wei , Zhou Shi
Published: March 2021

Purpose

This research aims to analyze the diagnostic contribution of different discriminative regions of the breast ultrasound image and develop a more effective diagnosis method taking advantage of the discriminative regions' complementarity.

Methods

First, the discriminative regions of the original breast ultrasound image as the inner region of the lesion, the marginal zone of the lesion, and the posterior echo region of the lesion were defined. The pretrained Inception‐V3 network was used to analyze the diagnostic contribution of these discriminative regions. Then, the network was applied to extract the deep features of the original image and the other three discriminative region images. Since there are many features, principal components analysis (PCA) was used to reduce the dimensionality of the extracted deep features. The selected deep features from different discriminative regions were fused to original image features and sent to the stacking ensemble learning classifier for classification experiments. In this study, 479 cases of breast ultrasound images, including 356 benign lesions and 123 malignant ones, were collected retrospectively and randomly divided into the training and validation set.

Results

Experimental results show that by using Inception‐V3, the diagnostic performance of each discriminative region is different, and the diagnostic accuracy and the area under the ROC curve (AUC) of the lesion marginal zone image (78.3%, 0.798) are higher than those of the lesion inner region image (73.3%, 0.763) and the posterior echo region image (71.7%, 0.688), but lower than those of the original image (80.0%, 0.817). Furthermore, the best classification performance was obtained when all the four types of deep features (from the original image and three discriminative region images) were fused, and the ensemble learning for classification evaluation was employed. Compared with the original image, the classification accuracy and AUC increased from 80.83%, 0.818 to 85.00%, 0.872, and the classification sensitivity and specificity varied from 0.710, 0.798 to 0.871, 0.787.

Conclusions

The inner region of the lesion, the marginal zone of the lesion, and the posterior echo region of the lesion play significant roles in the diagnosis of the breast ultrasound image. Deep feature fusion of these three kinds of images and the original image can effectively improve the accuracy of diagnosis.
Three‐dimensional image volumes from two‐dimensional digitally reconstructed radiographs: A deep learning approach in lower limb CT scans
Authors: Almeida Diogo F. , Astudillo Patricio , Vandermeulen Dirk
Published: March 2021

Purpose

Three‐dimensional (3D) reconstructions of the human anatomy have been available for surgery planning or diagnostic purposes for a few years now. The different image modalities usually rely on several consecutive two‐dimensional (2D) acquisitions in order to reconstruct the 3D volume. Hence, such acquisitions are expensive, time‐demanding and often expose the patient to an undesirable amount of radiation. For such reasons, along the most recent years, several studies have been proposed that extrapolate 3D anatomical features from merely 2D exams such as x rays for implant templating in total knee or hip arthroplasties.

Method

The presented study shows an adaptation of a deep learning‐based convolutional neural network to reconstruct 3D volumes from a mere 2D digitally reconstructed radiograph from one of the most extensive lower limb computed tomography datasets available. This novel approach is based on an encoder‐decoder architecture with skip connections and a multidimensional Gaussian filter as data augmentation technique.

Results

The results achieved promising values when compared against the ground truth volumes, quantitatively yielding an average of 0.77 ± 0.05 structured similarity index.

Conclusions

A novel deep learning‐based approach to reconstruct 3D medical image volumes from a single x‐ray image was shown in the present study. The network architecture was validated against the original scans presenting SSIM values of 0.77 ± 0.05 and 0.78 ± 0.06, respectively for the knee and the hip crop.
Apparent exchange rate imaging: On its applicability and the connection to the real exchange rate
Authors: Ludwig Dominik , Laun Frederik Bernd , Ladd Mark Edward , Bachert Peter , Kuder Tristan Anselm
Published: March 2021

Purpose

Water exchange between the intracellular and extracellular space can be measured using apparent exchange rate (AXR) imaging. The aim of this study was to investigate the relationship between the measured AXR and the geometry of diffusion restrictions, membrane permeability, and the real exchange rate, as well as to explore the applicability of AXR for typical human measurement settings.

Methods

The AXR measurements and the underlying exchange rates were simulated using the Monte Carlo method with different geometries, size distributions, packing densities, and a broad range of membrane permeabilities. Furthermore, the influence of SNR and sequence parameters was analyzed.

Results

The estimated AXR values correspond to the simulated values and show the expected proportionality to membrane permeability, except for fast exchange (ie, ) and small packing densities. Moreover, it was found that the duration of the filter gradient must be shorter than . In cell size and permeability distributions, AXR depends on the average surface‐to‐volume ratio, permeability, and the packing density. Finally, AXR can be reliably determined in the presence of orientation dispersion in axon‐like structures with sufficient gradient sampling (ie, 30 gradient directions).

Conclusion

Currently used experimental settings for in vivo human measurements are well suited for determining AXR, with the exception of single‐voxel analysis, due to limited SNR. The detection of changes in membrane permeability in diseased tissue is nonetheless challenging because of the AXR dependence on further factors, such as packing density and geometry, which cannot be disentangled without further knowledge of the underlying cell structure.
Black‐Asian Solidarities and the Impasses of “How‐To” Anti‐racisms
Authors: Rubio Elizabeth Hanna
Published: March 2021

During the 2020 summer of global uprisings in defense of Black life, widely circulated anti‐racist reading lists created heightened demand for books that promised to teach readers how to examine their internalized racism. Situated in U.S. racial liberalism’s extensive literary genealogy, anti‐racist “how‐to” literature has historically swooped in during moments of heightened racialized confusion to restore narratives of American exceptionalism. This literature sustains the tenuous promise that racism is something that one can challenge in interpersonal relationships and by following specific steps toward individualized behavior correction. Building on a broader body of work that has critiqued liberal anti‐racisms for detracting from abolitionst struggles against racialized injustice, this article specifically frames the limitations that “how‐to anti‐racisms” place on transgressive multiracial coalition building. Through ethnographic analysis of discourses and practices that move through various sites of contemporary Black‐Asian American activist encounters, I build on Black and radical women of color feminist theorizations of solidarity to show how “how‐tos” destabilize coalition building by overdetermining resolutions to conflict. I argue that in “settling” anti‐racism into a repertoire of predetermined steps, how‐to‐ism constrains the contradiction, anger, and uncertainty that is fundamental to forging the radical accountability central to abolitionist work.
“Stepping in the Gap to Make Family”: Care Calculation and Grandparent Caregiving in Detroit, Michigan
Authors: Richards Fayana
Published: March 2021

Scholars have long recognized the role that older Black American women play in providing care for their own grandchildren, nieces, nephews, and even non‐kin, arguing that kinship and caregiving relationships have been shaped by historical and structural factors. In this article, I consider intensive grandchild caregiving among Black American grandparents, primarily grandmothers, living in Detroit, Michigan. I highlight how the decision and process of providing care involves a “care calculation” where grandmothers evaluate their decision to caregive against existing financial, emotional, and bodily resources. In doing so, I argue that grandparent caregiving should be understood as a responsive and intentional process, where the decision to care for grandchildren and the performance of care work is more than simply responding to a set of certain circumstances and/or obligations based on biological kinship relations.
Potential Effects of Bigheaded Carps on Four Laurentian Great Lakes Food Webs
Authors: Rutherford Edward S. , Zhang Hongyan , Kao Yu-Chun , Mason Doran M. , Shakoor Ali , Bouma-Gregson Keith , Breck Jason T. , Lodge David M. , Chadderton W. Lindsay
Published: March 2021

Bigheaded carps (BHCs; Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis) are economically and culturally important in Asia and Europe but are considered highly invasive throughout the Mississippi River watershed and pose a threat to the food web and fisheries of the Laurentian Great Lakes. We used the Ecopath with Ecosim model framework to evaluate potential risk of BHC population growth and food web effects in four Great Lakes habitats, including mesotrophic waters of Saginaw Bay (Lake Huron) and Lake Erie and the oligotrophic main basins of Lakes Michigan and Huron. We simulated BHC population growth and food web effects under different scenarios of BHC production rates, prey vulnerability to BHCs, and availability of age-0 BHCs to predation by salmonines. In the main basins of Lakes Michigan and Huron, the projected BHC population growth was low or negative, with a projected final BHC biomass of 0.5–1.1 times the initial introductory biomass (2% of total fish biomass for each BHC species), and BHCs had negligible effects on most food web groups across all scenarios. In contrast, in Saginaw Bay and Lake Erie, the projected BHC biomass was 2.5–12.5 times higher than the initial biomass across all scenarios, and the largest increases occurred under scenarios of high prey vulnerability to BHCs and high BHC production rates. High projected BHC biomass in Saginaw Bay and Lake Erie had negative effects on zooplankton and planktivorous fish groups and mixed effects on piscivores but had relatively negligible effects on most other food web groups across all scenarios. Our results are consistent with reported BHC effects on food webs in the Mississippi River and its tributaries and inform efforts to prevent BHC invasion of the Great Lakes.
Spectral Wavelet‐feature Analysis and Classification Assisted Denoising for enhancing magnetic resonance spectroscopy
Authors: Ji Bing , Hosseini Zahra , Wang Liya , Zhou Lei , Tu Xinhua , Mao Hui
Published: March 2021

Magnetic resonance spectroscopy (MRS) is capable of revealing important biochemical and metabolic information of tissues noninvasively. However, the low concentrations of metabolites often lead to poor signal‐to‐noise ratio (SNR) and a long acquisition time. Therefore, the applications of MRS in detection and quantitative measurements of metabolites in vivo remain limited. Reducing or even eliminating noise can improve SNR sufficiently to obtain high quality spectra in addition to increasing the number of signal averaging (NSA) or the field strength, both of which are limited in clinical applications. We present a Spectral Wavelet‐feature ANalysis and Classification Assisted Denoising (SWANCAD) approach to differentiate signal and noise peaks in magnetic resonance spectra based on their respective wavelet features, followed by removing the identified noise components to improve SNR. The performance of this new denoising approach was evaluated by measuring and comparing SNRs and quantified metabolite levels of low NSA spectra (e.g. NSA = 8) before and after denoising using the SWANCAD approach or by conventional spectral fitting and denoising methods, such as LCModel and wavelet threshold methods, as well as the high NSA spectra (e.g. NSA = 192) recorded in the same sampling volumes. The results demonstrated that SWANCAD offers a more effective way to detect the signals and improve SNR by removing noise from the noisy spectra collected with low NSA or in the subminute scan time (e.g. NSA = 8 or 16 s). The potential applications of SWANCAD include using low NSA to accelerate MRS acquisition while maintaining adequate spectroscopic information for detection and quantification of the metabolites of interest when a limited time is available for an MRS examination in the clinical setting.
Corrigendum 2 to: A geometric view of Krylov subspace methods on singular systems
Authors: Hayami Ken , Sugihara Kota
Published: March 2021

In [Hayami K, Sugihara M. Numer Linear Algebra Appl. 2011; 18:449–469], the authors analyzed the convergence behavior of the generalized minimal residual (GMRES) method for the least squares problem , where A ∈ Rn × n may be singular and , by decomposing the algorithm into the range and its orthogonal complement components. However, we found that the proof of the fact that GMRES gives a least squares solution if was not complete. In this article, we will give a complete proof.
Condition numbers for the truncated total least squares problem and their estimations
Authors: Meng Qing‐Le , Diao Huai‐An , Bai Zheng‐Jian
Published: March 2021

In this paper, we present explicit expressions for the mixed and componentwise condition numbers of the truncated total least squares (TTLS) solution of under the genericity condition, where A is a m × n real data matrix and is a real m‐vector. Moreover, we reveal that normwise, componentwise, and mixed condition numbers for the TTLS problem can recover the previous corresponding counterparts for the total least squares (TLS) problem when the truncated level of the TTLS problem is n. When A is a structured matrix, the structured perturbations for the structured truncated TLS (STTLS) problem are investigated and the corresponding explicit expressions for the structured normwise, componentwise, and mixed condition numbers for the STTLS problem are obtained. Furthermore, the relationships between the structured and unstructured normwise, componentwise, and mixed condition numbers for the STTLS problem are studied. We devise reliable condition estimation algorithms for the TTLS problem by utilizing small‐sample statistical condition estimation techniques. The proposed condition estimation algorithms employ the singular value decomposition (SVD) of the augmented matrix to reduce the computational complexity, where both unstructured and structured normwise, mixed, and componentwise condition estimations are considered. The proposed condition estimation algorithms can be integrated into the SVD‐based direct solver for the small and medium size TTLS problem to give the error estimation for the numerical TTLS solution. Numerical experiments are reported to illustrate the reliability of the proposed condition estimation algorithms.
An XFEM multilayered heaviside enrichment for fracture propagation with reduced enhanced degrees of freedom
Authors: Bybordiani Milad , Latifaghili Amir , Soares Delfim , Godinho Luis , Dias‐da‐Costa Daniel
Published: March 2021

The development of advanced numerical techniques such as eXtended/Generalized Finite Elements Methods (XFEM/GFEM) has provided means for accurate prediction of material failure. However, the present theories mostly rely on a global formulation, where the system of equations is subject to progressive dimension increase with crack evolution. In this regard, an independent multilayered enrichment is proposed for the XFEM/GFEM family of methods where a few elements in close proximity are assigned to an enrichment layer independent of the remaining ones. The enhanced degrees of freedom can be condensed out at the layer level, which leads to system dimensions, sparsity, and bandness identical to those of the underlying finite elements. Nodal and elemental enrichment methods are shown to be particular limit cases of present approach. The robustness of the proposed approach is first demonstrated in element‐level examples. The use of only few adjacent elements in a group enrichment is shown to suffice for acceptable results while the order of the condition number of the final stiffness matrix resembles the underlying uncracked finite element counterpart. Finally, using several structural examples, the accuracy and robustness of the method is shown in terms of force–displacement response, stress fields, and traction continuity in nonlinear problems.
Stroke survivors’ experiences with rebuilding life in the community and exercising at home: A qualitative study
Authors: van Dongen Lisa , Hafsteinsdóttir Thóra B. , Parker Ethna , Bjartmarz Ingibjörg , Hjaltadóttir Ingibjörg , Jónsdóttir Helga
Published: March 2021

Aim

This study aimed to explore how stroke survivors deal with stroke‐related impairments when rebuilding their lives in the community and their experiences of exercising at home.

Design

An explorative and descriptive qualitative study.

Methods

A purposive sample of ten stroke survivors residing at home was recruited to explore experiences of rebuilding their lives in the community and exercising at home. One focus group interview was conducted followed by semi‐structured interviews. Data were analysed using thematic analysis.

Results

Three main themes were identified: “Framing exercise within the context of everyday life” describes how stroke survivors integrate exercise in everyday activities with varying success and the social importance of exercising; “Managing the challenges of physical impairment” describes the taxing undertakings in daily living, loss of concentration and identity; “Long‐term challenges of everyday life” describes how the stroke survivors manage depression and live with a sense of uncertainty.