bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Abyssal Hill Roughness on the Benthic Tide
Authors: Shakespeare Callum J. , Arbic Brian K. , McC. Hogg Andrew
Published: May 2021

The flow of tides over rough bathymetry in the deep ocean generates baroclinic motion including internal waves and bottom‐trapped tides. The stresses generated by this motion feedback on the amplitude and phase of the large‐scale tide. Quantifying the stresses associated with tidal flow over abyssal hills is especially important, as this scale of bathymetry is often unresolved in global baroclinic tide models, and the stresses must therefore be parameterized. Here, we extend the previous theoretical work of the authors to determine the amplitude, phasing, and vertical location of the stresses exerted on a flow driven by a time‐periodic body force when it encounters rough bathymetry. The theory compares favorably with a suite of fully nonlinear numerical simulations. It is shown that all topographic stresses are applied directly above the bathymetry, leading to a two‐layer baroclinic flow, with the near‐bottom spatial‐mean flow (the benthic tide) strongly modified by topographic stresses, and the flow at height unperturbed by the presence of topography. Our results provide a framework to improve baroclinic tide models by (i) providing a simple parameterization for the subinertial stress which is currently not included in any models, (ii) establishing that parameterized stresses should be applied in the diffusive boundary layer directly above the topography, independent of where internal tides may dissipate, and (iii) identifying a minimum resolution of ∼10 km for baroclinic tidal models to adequately capture wave resonance effects that can significantly impact the magnitude of the benthic tide.
Tiny Volcanoes Are a Big Deal on Mars
Authors: Klemetti Erik
Published: May 2021

Cinder cones and fissure vents provide clues about the evolution of the Red Planet’s mantle and crust.
Shaping the Future of Science: COVID‐19 Highlighting the Importance of GeoHealth
Authors: Gorris Morgan E. , Anenberg Susan C. , Goldberg Daniel L. , Kerr Gaige Hunter , Stowell Jennifer D. , Tong Daniel , Zaitchik Benjamin F.
Published: May 2021

From the heated debates over the airborne transmission of the novel coronavirus to the abrupt Earth system changes caused by the sudden lockdowns, the dire circumstances resulting from the coronavirus disease 2019 (COVID‐19) pandemic have brought the field of GeoHealth to the forefront of visibility in science and policy. The pandemic has inadvertently provided an opportunity to study how human response has impacted the Earth system, how the Earth system may impact the pandemic, and the capacity of GeoHealth to inform real‐time policy. The lessons learned throughout our responses to the COVID‐19 pandemic are shaping the future of GeoHealth.
Evaluation of Flow‐Log Data From Crystalline Rocks With Steady‐State Pumping and Ambient Flow
Authors: Zou Liangchao , Cvetkovic Vladimir
Published: May 2021

Alternative evaluation methods are assessed by numerical modeling of pumping tests in three‐dimensional fracture networks. Network scale heterogeneity, fracture‐to‐fracture scale heterogeneity, and individual fracture scale heterogeneity (fracture roughness) are considered as representative of multi‐scale hydraulic and structural heterogeneity of crystalline rocks. The results show that ambient hydraulic gradient has a negligible effect on transmissivity inference of sparsely fractured rocks using flow logs. Consequently, the common dual pumping method used to account for the ambient flow can be simplified to a single pumping. This could potentially reduce the site characterization effort in typical applications such as nuclear waste disposal. The transmissivity inference method based on the Thiem solution provides representative median transmissivity. It, however, underestimates relatively high transmissivities due to its inability to account for the impact of fracture roughness. These findings have important implications regarding pumping test schemes and data interpretation methods in the hydrogeological characterization of sparsely fractured rocks using flow‐log data.
Explaining the Shortcomings of Log‐Transforming the Dependent Variable in Regression Models and Recommending a Better Alternative: Evidence From Soil CO2 Emission Studies
Authors: Liaw Kao‐Lee , Khomik Myroslava , Arain M. Altaf
Published: May 2021

Log‐transforming the dependent variable of a regression model, though convenient and frequently used, is accompanied by an under‐prediction problem. We found that this underprediction can reach up to 20%, which is significant in studies that aim to estimate annual budgets. The fundamental reason for this problem is simply that the log‐function is concave, and it has nothing to do with whether the dependent variable has a log‐normal distribution or not. Using field‐observed data of soil CO2 emission, soil temperature and soil moisture in a saturated‐specification of a regression model for predicting emissions, we revealed that the under‐predictions of the log‐transformed approach were pervasive and systematically biased. The key determinant of the problem's severity was the coefficient of variation in the dependent variable that differed among different combinations of the values of the explanatory factors. By applying a parsimonious (Gaussian‐Gamma) specification of the regression model to data from four different ecosystems, we found that this under‐prediction problem was serious to various extents, and that for a relatively weak explanatory factor, the log‐transformed approach is prone to yield a physically nonsensical estimated coefficient. Finally, we showed and concluded that the problem can be avoided by switching to the nonlinear approach, which does not require the assumption of homoscedasticity for the error term in computing the standard errors of the estimated coefficients.
CXCR4 intracellular protein promotes drug resistance and tumorigenic potential by inversely regulating the expression of Death Receptor 5
Authors: Nengroo Mushtaq A. , Maheshwari Shrankhla , Singh Akhilesh , Verma Ayushi , Arya Rakesh K. , Chaturvedi Priyank , Saini Krishan K. , Singh Anup K. , Sinha Abhipsa , Meena Sanjeev , Gupta Annapurna , Mishra Anjali , Sarkar Jayanta , Datta Dipak
Published: May 2021

Chemokine receptor CXCR4 overexpression in solid tumors has been strongly associated with poor prognosis and adverse clinical outcome. However, blockade of CXCL12-CXCR4 signaling axis by inhibitors like Nox-A12, FDA approved CXCR4 inhibitor drug AMD3100 have shown limited clinical success in cancer treatment. Therefore, exclusive contribution of CXCR4-CXCL12 signaling in pro-tumorigenic function is questionable. In our pursuit to understand the impact of chemokine signaling in carcinogenesis, we reveal that instead of CXCR4-CXCL12 signaling, presence of CXCR4 intracellular protein augments paclitaxel resistance and pro-tumorigenic functions. In search of pro-apoptotic mechanisms for CXCR4 mediated drug resistance; we discover that DR5 is a new selective target of CXCR4 in breast and colon cancer. Further, we detect that CXCR4 directs the differential recruitment of transcription factors p53 and YY1 to the promoter of DR5 in course of its transcriptional repression. Remarkably, inhibiting CXCR4-ligand-mediated signals completely fails to block the above phenotype. Overexpression of different mutant versions of CXCR4 lacking signal transduction capabilities also result in marked downregulation of DR5 expression in colon cancer indeed confirms the reverse relationship between DR5 and intracellular CXCR4 protein expression. Irrespective of CXCR4 surface expression, by utilizing stable gain and loss of function approaches, we observe that intracellular CXCR4 protein selectively resists and sensitizes colon cancer cells against paclitaxel therapy in vitro and in vivo. Finally, performing TCGA data mining and using human breast cancer patient samples, we demonstrate that expression of CXCR4 and DR5 are inversely regulated. Together, our data suggest that targeting CXCR4 intracellular protein may be critical to dampen the pro-tumorigenic functions of CXCR4.
TRIM25 regulates oxaliplatin resistance in colorectal cancer by promoting EZH2 stability
Authors: Zhou Sha , Peng Jianhong , Xiao Liuniu , Zhou Caixia , Fang Yujing , Ou Qingjian , Qin Jiayi , Liu Mengzhong , Pan Zhizhong , Hou Zhenlin
Published: May 2021

Resistance to chemotherapy remains the major cause of treatment failure in patients with colorectal cancer (CRC). Here, we identified TRIM25 as an epigenetic regulator of oxaliplatin (OXA) resistance in CRC. The level of TRIM25 in OXA-resistant patients who experienced recurrence during the follow-up period was significantly higher than in those who had no recurrence. Patients with high expression of TRIM25 had a significantly higher recurrence rate and worse disease-free survival than those with low TRIM25 expression. Downregulation of TRIM25 dramatically inhibited, while overexpression of TRIM25 increased, CRC cell survival after OXA treatment. In addition, TRIM25 promoted the stem cell properties of CRC cells both in vitro and in vivo. Importantly, we demonstrated that TRIM25 inhibited the binding of E3 ubiquitin ligase TRAF6 to EZH2, thus stabilizing and upregulating EZH2, and promoting OXA resistance. Our study contributes to a better understanding of OXA resistance and indicates that inhibitors against TRIM25 might be an excellent strategy for CRC management in clinical practice.
TP53INP1 exerts neuroprotection under ageing and Parkinson’s disease-related stress condition
Authors: Dinh Emilie , Rival Thomas , Carrier Alice , Asfogo Noemi , Corti Olga , Melon Christophe , Salin Pascal , Lortet Sylviane , Kerkerian-Le Goff Lydia
Published: May 2021

TP53INP1 is a stress-induced protein, which acts as a dual positive regulator of transcription and of autophagy and whose deficiency has been linked with cancer and metabolic syndrome. Here, we addressed the unexplored role of TP53INP1 and of itsDrosophilahomolog dDOR in the maintenance of neuronal homeostasis under chronic stress, focusing on dopamine (DA) neurons under normal ageing- and Parkinson’s disease (PD)-related context.Trp53inp1−/−mice displayed additional loss of DA neurons in the substantia nigra compared to wild-type (WT) mice, both with ageing and in a PD model based on targeted overexpression of α-synuclein. NigralTrp53inp1expression of WT mice was not significantly modified with ageing but was markedly increased in the PD model.Trp53inp2expression showed similar evolution and did not differ between WT andTrp53inp1−/−mice. InDrosophila, pan-neuronaldDORoverexpression improved survival under paraquat exposure and mitigated the progressive locomotor decline and the loss of DA neurons caused by the human α-synuclein A30P variant.dDORoverexpression in DA neurons also rescued the locomotor deficit in flies with RNAi-induced downregulation ofdPINK1ordParkin. Live imaging, confocal and electron microscopy in fat bodies, neurons, and indirect flight muscles showed thatdDORacts as a positive regulator of basal autophagy and mitophagy independently of the PINK1-mediated pathway. Analyses in a mammalian cell model confirmed that modulatingTP53INP1levels does not impact mitochondrial stress-induced PINK1/Parkin-dependent mitophagy. These data provide the first evidence for a neuroprotective role of TP53INP1/dDOR and highlight its involvement in the regulation of autophagy and mitophagy in neurons.
Graphether: a reversible and high-capacity anode material for sodium-ion batteries with ultrafast directional Na-ion diffusion
Authors: Ye Xiao-Juan , Zhu Gui-Lin , Meng Lan , Guo Yan-Dong , Liu Chun-Sheng
Published: May 2021

Two-dimensional graphether as a reversible and high-capacity anode material for sodium-ion batteries with ultrafast directional Na-ion diffusion.
Live and ultrasound-inactivated Lacticaseibacillus casei modulate the intestinal microbiota and improve biochemical and cardiovascular parameters in male rats fed a high-fat diet
Authors: Brandão Larissa Ramalho , de Brito Alves José Luiz , da Costa Whyara Karoline Almeida , Ferreira Georgianna de Araújo Henriques , de Oliveira Matthaws Pereira , Gomes da Cruz Adriano , Braga Valdir de Andrade , Aquino Jailane de Souza , Vidal Hubert , Noronha Melline Fontes , Cabral Lucélia , Pimentel Tatiana Colombo , Magnani Marciane
Published: May 2021

This study aimed to evaluate the effects of ingestion of live and ultrasound-inactivated Lacticaseibacillus casei 01 for 28 days on biochemical and cardiovascular parameters, and intestinal microbiota of rats fed a high-fat diet.
Inhibition of the intestinal postprandial glucose transport by gallic acid and gallic acid derivatives
Authors: Wang Huijun , Fowler Mark I. , Messenger David J. , Ordaz-Ortiz Jose Juan , Gu Xuelan , Shi Songshan , Terry Leon A. , Berry Mark J. , Lian Guoping , Wang Shunchun
Published: May 2021

Gallic acid structures are crucial for glucose transport inhibition in natural products.
Metallic glue for designing composite materials with tailorable properties
Authors: Fu Jianan , Yang Jian , Wu Kai , Lin Hongji , Wen Wenxin , Ruan Wenqing , Ren Shuai , Zhang Zhenxuan , Liang Xiong , Ma Jiang
Published: May 2021

A new and universal method for developing novel materials with tailorable properties by using metallic glasses as a glue to bond two materials as composites.
A dual responsive photonic liquid for independent modulation of color brightness and hue
Authors: Liu Yun , Fan Qingsong , Zhu Guanghao , Shi Gongpu , Ma Huiru , Li Wei , Wu Tianlong , Chen Jitao , Yin Yadong , Guan Jianguo
Published: May 2021

The brightness and hue of structural colors can be independently, continuously, and reversibly tuned in an aqueous suspension containing Fe3O4@poly(N-isopropyl acrylamide) flexible photonic nanochains by changing the magnetic field and temperature.
Photo-directing chemoepitaxy: the versatility of poly(aryl methacrylate) films in tuning block copolymer wetting
Authors: Zhao Jiacheng , McCallum Francis J. , Yu Ye , Fu Changkui , Kaitz Joshua A. , Cameron James F. , Trefonas Peter , Blakey Idriss , Peng Hui , Whittaker Andrew K.
Published: May 2021

UV irradiated poly(aryl methacrylate) films can induce a change in the orientation of the domains of an overlayer of PS-b-PMMA from parallel to perpendicular lamellar structures.
A single active ring model with velocity self-alignment
Authors: Teixeira Emanuel F. , Fernandes Heitor C. M. , Brunnet Leonardo G.
Published: May 2021

Active particles held together in a ring. Decreasing bending and noise intensities induces a change from a persistent random walk to an expontaneous collective motion polarized along the larger ring dimension, guiding the movement.
Oxygen ion transport in doped ceria: effect of vacancy trapping
Authors: Kilic Mehmet Emin , Lee Jong-Ho , Lee Kwang-Ryeol
Published: May 2021

The diffusion of oxygen in a ceria electrolyte is governed by the vacancy trapping effect of trivalent dopants.
Ionophobic nanopores enhancing the capacitance and charging dynamics in supercapacitors with ionic liquids
Authors: Gan Zhongdong , Wang Yanlei , Wang Mi , Gao Enlai , Huo Feng , Ding Weilu , He Hongyan , Zhang Suojiang
Published: May 2021

This work unravels a new charging mechanism of “co-ion adsorption” in the supercapacitor with ionophobic nanopores, which can synergistically promote the differential capacitance and charging dynamics of supercapacitors with ionic liquids.
Low-work-function LaB6 for realizing photodynamic-enhanced photothermal therapy
Authors: Tang Shuanglong , Huang Weicheng , Gao Yan , An Na , Wu Yadong , Yang Bin , Yan Mei , Cao Jingyan , Guo Chongshen
Published: May 2021

This work presents plasmonic-enhanced ROS activation on low-work-function material for direct near-infrared-driven photodynamic-enhanced photothermal synergistic treatment.
Singlet-oxygen generated by a metal–organic framework for electrochemical biosensing
Authors: Ling Pinghua , Cheng Shan , Chen Nuo , Gao Feng
Published: May 2021

A sensing strategy with the advantages of enzymes and photoelectrochemical sensing with amplified signals was designed for electrochemical biosensing.
Exploring a layered iodide perovskite crystal with centimetered dimension for extended spectral polarization-sensitive photodetection
Authors: Li Xiaoqi , Li Dong , Peng Yu , Liu Yi , Wang Jiaqi , Li Lina , Yao Yunpeng , Liu Xitao , Luo Junhua
Published: May 2021

Via strategies of symmetry-reduction and halide remolding, a narrow bandgap layered iodide perovskite, (s-BA)2(MA)Pb2I7, has been developed which exhibits highly structural anisotropy and extended spectral polarization-sensitive photoresponse.
Integrated analysis of ceRNA network and tumor-infiltrating immune cells in esophageal cancer
Authors: Chen Yuhua , Zhou Hao , Wang Zhendong , Huang Zhanghao , Wang Jinjie , Zheng Miaosen , Ni Xuejun , Liu Lei
Published: May 2021

Background: Esophageal cancer (ESCA) is one of the most commonly diagnosed cancers in the world. Tumor immune microenvironment is closely related to tumor prognosis. The present study aimed at analyzing the competing endogenous RNA (ceRNA) network and tumor-infiltrating immune cells in ESCA.

Methods: The expression profiles of mRNAs, lncRNAs, and miRNAs were downloaded from the Cancer Genome Atlas database. A ceRNA network was established based on the differentially expressed RNAs by Cytoscape. CIBERSORT was applied to estimate the proportion of immune cells in ESCA. Prognosis-associated genes and immune cells were applied to establish prognostic models basing on Lasso and multivariate Cox analyses. The survival curves were constructed with Kaplan–Meier method. The predictive efficacy of the prognostic models was evaluated by the receiver operating characteristic (ROC) curves.

Results: The differentially expressed mRNAs, lncRNAs, and miRNAs were identified. We constructed the ceRNA network including 23 lncRNAs, 19 miRNAs, and 147 mRNAs. Five key molecules (HMGB3, HOXC8, HSPA1B, KLHL15, and RUNX3) were identified from the ceRNA network and five significant immune cells (plasma cells, T cells follicular helper, monocytes, dendritic cells activated, and neutrophils) were selected via CIBERSORT. The ROC curves based on key genes and significant immune cells all showed good sensitivity (AUC of 3-year survival: 0.739, AUC of 5-year survival: 0.899, AUC of 3-year survival: 0.824, AUC of 5-year survival: 0.876). There was certain correlation between five immune cells and five key molecules.

Conclusion: The present study provides an effective bioinformatics basis for exploring the potential biomarkers of ESCA and predicting its prognosis.
Molecular genetics of renal ciliopathies
Authors: Barroso-Gil Miguel , Olinger Eric , Sayer John A.
Published: May 2021

Renal ciliopathies are a heterogenous group of inherited disorders leading to an array of phenotypes that include cystic kidney disease and renal interstitial fibrosis leading to progressive chronic kidney disease and end-stage kidney disease. The renal tubules are lined with epithelial cells that possess primary cilia that project into the lumen and act as sensory and signalling organelles. Mutations in genes encoding ciliary proteins involved in the structure and function of primary cilia cause ciliopathy syndromes and affect many organ systems including the kidney. Recognised disease phenotypes associated with primary ciliopathies that have a strong renal component include autosomal dominant and recessive polycystic kidney disease and their various mimics, including atypical polycystic kidney disease and nephronophthisis. The molecular investigation of inherited renal ciliopathies often allows a precise diagnosis to be reached where renal histology and other investigations have been unhelpful and can help in determining kidney prognosis. With increasing molecular insights, it is now apparent that renal ciliopathies form a continuum of clinical phenotypes with disease entities that have been classically described as dominant or recessive at both extremes of the spectrum. Gene-dosage effects, hypomorphic alleles, modifier genes and digenic inheritance further contribute to the genetic complexity of these disorders. This review will focus on recent molecular genetic advances in the renal ciliopathy field with a focus on cystic kidney disease phenotypes and the genotypes that lead to them. We discuss recent novel insights into underlying disease mechanisms of renal ciliopathies that might be amenable to therapeutic intervention.
Leucine-rich repeat kinase 2-related functions in GLIA: an update of the last years
Authors: Filippini Alice , Gennarelli Massimo , Russo Isabella
Published: May 2021

Missense mutations in the leucine-rich repeat kinase-2 (LRRK2) gene represent the most common cause of autosomal dominant Parkinson's disease (PD). In the years LRRK2 has been associated with several organelles and related pathways in cell. However, despite the significant amount of research done in the past decade, the contribution of LRRK2 mutations to PD pathogenesis remains unknown. Growing evidence highlights that LRRK2 controls multiple processes in brain immune cells, microglia and astrocytes, and suggests that deregulated LRRK2 activity in these cells, due to gene mutation, might be directly associated with pathological mechanisms underlying PD. In this brief review, we recapitulate and update the last LRRK2 functions dissected in microglia and astrocytes. Moreover, we discuss how dysfunctions of LRRK2-related pathways may impact glia physiology and their cross-talk with neurons, thus leading to neurodegeneration and progression of PD.
Maternal microvascular dysfunction during preeclamptic pregnancy
Authors: Stanhewicz Anna E. , Nuckols Virginia R. , Pierce Gary L.
Published: May 2021

Preeclampsia is a hypertensive disorder of pregnancy effecting ∼5–8% of pregnancies in the United States, and ∼8 million pregnancies worldwide. Preeclampsia is clinically diagnosed after the 20th week of gestation and is characterized by new onset hypertension accompanied by proteinuria and/or thrombocytopenia, renal insufficiency, impaired liver function, pulmonary edema, or cerebral or visual symptoms. This broad definition emphasizes the heterogeneity of the clinical presentation of preeclampsia, but also underscores the role of the microvascular beds, specifically the renal, cerebral, and hepatic circulations, in the pathophysiology of the disease. While the diagnostic criteria for preeclampsia relies on the development of de novo hypertension and accompanying clinical symptoms after 20-week gestation, it is likely that subclinical dysfunction of the maternal microvascular beds occurs in parallel and may even precede the development of overt cardiovascular symptoms in these women. However, little is known about the physiology of the non-reproductive maternal microvascular beds during preeclampsia, and the mechanism(s) mediating microvascular dysfunction during preeclamptic pregnancy are largely unexplored in humans despite their integral role in the pathophysiology of the disease. Therefore, the purpose of this review is to provide a summary of the existing literature on maternal microvascular dysfunction during preeclamptic pregnancy by reviewing the functional evidence in humans, highlighting potential mechanisms, and providing recommendations for future work in this area.
Murine endometrial-derived mesenchymal stem cells suppress experimental autoimmune encephalomyelitis depending on indoleamine-2,3-dioxygenase expression
Authors: Manganeli Polonio Carolina , Longo de Freitas Carla , Garcia de Oliveira Marília , Rossato Cristiano , Nogueira Brandão Wesley , Ghabdan Zanluqui Nágela , Gomes de Oliveira Lilian , Ayumi Nishiyama Mimura Luiza , Braga Barros Silva Maysa , Lúcia Garcia Calich Vera , Gil Nisenbaum Marcelo , Halpern Silvio , Evangelista Lucila , Maluf Mariangela , Perin Paulo , Eduardo Czeresnia Carlos , Schatzmann Peron Jean Pierre
Published: May 2021

Cellular therapy with mesenchymal stem cells (MSCs) is a huge challenge for scientists, as little translational relevance has been achieved. However, many studies using MSCs have proved their suppressive and regenerative capacity. Thus, there is still a need for a better understanding of MSCs biology and the establishment of newer protocols, or to test unexplored tissue sources. Here, we demonstrate that murine endometrial-derived MSCs (meMSCs) suppress Experimental Autoimmune Encephalomyelitis (EAE). MSC-treated animals had milder disease, with a significant reduction in Th1 and Th17 lymphocytes in the lymph nodes and in the central nervous system (CNS). This was associated with increased Il27 and Cyp1a1 expression, and presence of IL-10-secreting T CD4+ cells. At EAE peak, animals had reduced CNS infiltrating cells, histopathology and demyelination. qPCR analysis evidenced the down-regulation of several pro-inflammatory genes and up-regulation of indoleamine-2,3-dioxygenase (IDO). Consistently, co-culturing of WT and IDO−/− meMSCs with T CD4+ cells evidenced the necessity of IDO on the suppression of encephalitogenic lymphocytes, and IDO−/− meMSCs were not able to suppress EAE. In addition, WT meMSCs stimulated with IL-17A and IFN-γ increased IDO expression and secretion of kynurenines in vitro, indicating a negative feedback loop. Pathogenic cytokines were increased when CD4+ T cells from AhR−/− mice were co-cultured with WT meMSC. In summary, our research evidences the suppressive activity of the unexplored meMSCs population, and shows the mechanism depends on IDO-kynurenines-Aryl hydrocarbon receptor (AhR) axis. To our knowledge this is the first report evidencing that the therapeutic potential of meMSCs relying on IDO expression.
Image‐denoising algorithm based on improved K‐singular value decomposition and atom optimization
Authors: Chen Rui , Pu Dong , Tong Ying , Wu Minghu
Published: May 2021

The traditional K‐singular value decomposition (K‐SVD) algorithm has poor image‐denoising performance under strong noise. An image‐denoising algorithm is proposed based on improved K‐SVD and dictionary atom optimization. First, a correlation coefficient‐matching criterion is used to obtain a sparser representation of the image dictionary. The dictionary noise atom is detected according to structural complexity and noise intensity and removed to optimize the dictionary. Then, non‐local regularity is incorporated into the denoising model to further improve image‐denoising performance. Results of the simulated dictionary recovery problem and application on a transmission line dataset show that the proposed algorithm improves the smoothness of homogeneous regions while retaining details such as texture and edge.
A critical comparison on attitude estimation: From gaussian approximate filters to coordinate‐free dual optimal control
Authors: Koumpis N. P. , Panagiotou P. A. , Arvanitakis I.
Published: May 2021

This paper conveys attitude and rate estimation without rate sensors by performing a critical comparison, validated by extensive simulations. The two dominant approaches to facilitate attitude estimation are based on stochastic and set‐membership reasoning. The first one mostly utilizes the commonly known Gaussian‐approximate filters, namely the EKF and UKF. Although more conservative, the latter seems to be more promising as it considers the inherent geometric characteristics of the underline compact state space and accounts—from first principles—for large model errors. The set‐theoretic approach from a control point of view is addressed, and it is shown that it can overcome reported deficiencies of the Bayesian architectures related to this problem, leading to coordinate‐free optimal filters. Lastly, as an example, a modified predictive filter is derived on the tangent bundle of the special orthogonal group .
Research on the protection scheme of MMC‐MTDC based on high frequency energy
Authors: Xue Shimin , Chen Shuo , Sun Yabing , Gu Cheng , Liu Baibing
Published: May 2021

The development of flexible HVDC transmission technology requires the improvement of the theory of relay protections. The protection method based on the time domain has poor resistance to transition resistance and is easily affected by interference factors. The protection based on frequency domain analysis can better reflect the essential characteristics of the fault, and it is also an urgent problem for relay protections. The blocking effect of boundary elements on both sides of the line on high‐frequency components is an important entry point for current protection research, but high‐frequency protections are very sensitive to noise signals. Therefore, this paper analyses the frequency characteristics of the voltage at the measuring point from the perspective of the traveling wave transmission process, and uses the S transform to design a protection method based on high‐frequency energy to realize the identification of internal and external faults. Finally, the ability to withstand transition resistance and anti‐noise of the protection proposed here is verified by using PSCAD/EMTDC. The protection can complete fault identification within 2 ms, which means that it has both reliability and quick action.
Cloud detection of GF‐7 satellite laser footprint image
Authors: Yao Jiaqi , Tang Xinming , Li Guoyuan , Guo Jinquan , Chen Jiyi , Yang Xiongdan , Ai Bo
Published: May 2021

In November 2019, the GaoFen‐7(GF‐7) satellite was equipped with China's first laser altimeter with full waveform recording capability, which obtains high‐precision long‐range three‐dimensional coordinates. The influence of clouds is noticeable for laser transmission, and a footprint camera is used to determine laser pointing and to image the ground. However, the cloud inevitably appears in the laser footprint image. In this study, the authors propose a cloud detection scheme for footprint images based on deep learning. First, an adaptive pooling model is proposed according to the characteristics of the cloud region. Next, model fusion was performed based on the SegNet and U‐Net training results. Finally, test time augmentation was used to enhance the data and to improve cloud detection accuracy. The experimental results show that the fusion result of the model was approximately 5% better than that of the traditional cloud detection algorithm, which improved the shortcomings of the traditional algorithm, such as poor detection effect for thin clouds and complex underlying cloud surfaces. The related conclusions have certain reference significance for GF‐7 data processing and related research on footprint images.
Crowd activity recognition in live video streaming via 3D‐ResNet and region graph convolution network
Authors: Kang Junpeng , Zhang Jing , Li Wensheng , Zhuo Li
Published: May 2021

Since the era of we‐media, live video industry has shown an explosive growth trend. For large‐scale live video streaming, especially those containing crowd events that may cause great social impact, how to identify and supervise the crowd activity in live video streaming effectively is of great value to push the healthy development of live video industry. The existing crowd activity recognition mainly uses visual information, rarely fully exploiting and utilizing the correlation or external knowledge between crowd content. Therefore, a crowd activity recognition method in live video streaming is proposed by 3D‐ResNet and regional graph convolution network (ReGCN). (1) After extracting deep spatiotemporal features from live video streaming with 3D‐ResNet, the region proposals are generated by region proposal network. (2) A weakly supervised ReGCN is constructed by making region proposals as graph nodes and their correlations as edges. (3) Crowd activity in live video streaming is recognised by combining the output of ReGCN, the deep spatiotemporal features and the crowd motion intensity as external knowledge. Four experiments are conducted on the public collective activity extended dataset and a real‐world dataset BJUT‐CAD. The competitive results demonstrate that our method can effectively recognise crowd activity in live video streaming.
Thigh muscle segmentation using a hybrid FRFCM‐based multi‐atlas method and morphology‐based interpolation algorithm
Authors: Molaie Malihe , Aghaeizadeh Zoroofi Reza
Published: May 2021

The volume of lower extremity muscles is affected by some diseases. Quantification of thigh muscles in medical images can lead to an easier investigation of these diseases. Most of the previous works in thigh muscle segmentation are based on models and atlases that require manually segmented datasets in 3D. As manual segmentation of these muscles is a time‐consuming task, in this work, only one initial slice is segmented by a new hybrid FRFCM‐based multi‐atlas method and other slices are segmented based on this slice. In the proposed method, after noise reduction, the muscle region is extracted from other tissues by the FRFCM method. Then, an initial slice of each dataset is segmented by a multi‐atlas method. The segmented muscles in the initial slice are used to segment muscles in the other slices of each dataset. The proposed method was evaluated with 20 CT datasets. The average DSC, Precision, and Sensitivity of the method for individual muscle segmentation were , , and , respectively. The quantitative and intuitive results of the proposed method show the better results of this method in comparison to other state‐of‐the‐art thigh muscle segmentation techniques.
Novel pediatric suspension of nanoparticulate zafirlukast for the treatment of asthma: Assessment and evaluation in animal model
Authors: Li Hongmei , Yao Yingying , Fu Huizhi
Published: May 2021

The aim of the present study was to formulate the novel pediatric suspension containing nanoparticulate Zafirlukast (ZFR) for the treatment of pediatric asthma. The ZFR loaded nanoparticles (NPs) were formulated by ionotropic external gelation method using tripolyphosphate (TPP) and Tween 80. NPs were characterized for drug loading, encapsulation efficiency, surface morphology, saturation solubility, particle size, zeta potential and polydispersity index (PDI). The optimized NP formulation was used for the development of suspension. The suspensions were characterized for pH, viscosity, sedimentation volume, dissolution and drug content. The encapsulation efficiency of NPs was found between 93.24% and 98.57% with drug loading in the range of 26.50–35.90%. All formulations were found of nanosized in nature (150–220 nm) with zeta potential (19.18–21.41 mV). PDI of all NP formulations was found less than 0.3. The NPs were spherical and smooth in nature. The saturation solubility of ZFR was enhanced nearly 16 times   as compared to pure ZFR. The optimized suspension showed almost 100% ZFR release within the period of 30 min. The reduction in lung resistance (RI) was found nearly four fold as compared to the control group animals. The study supported the efficacy of suspension containing nanoparticulate ZFR in asthmatic animals.
Antenna position optimization method based on adaptive genetic algorithm with self‐supervised differential operator for distributed coherent aperture radar
Authors: Yang Xiaopeng , Li Yuqing , Liu Feifeng , Lan Tian , Teng Long , Sarkar Tapan K.
Published: May 2021

The performance of the distributed coherent aperture radar (DCAR) is heavily influenced by the antenna positions. Therefore, an antenna position optimization method is proposed based on the adaptive genetic algorithm with a self‐supervised differential operator. In the proposed method, the antenna positions are firstly coded as the chromosomes of the population with multiple constraints, and the reciprocal of the peak side lobe level (PSLL) of the beam pattern is calculated as the fitness function for optimization. Then, the adaptive probabilities are calculated for the crossover and mutation of chromosomes and a self‐supervised differential operator is utilized in the mutation. Finally, the optimal antenna positions for DCAR can be obtained with the lowest PSLL compared with the existing methods. The effectiveness of the proposed method is verified by linear and planar DCARs, respectively.
General design methodology of code multi‐correlator discriminator for GNSS multi‐path mitigation
Authors: Qi Yunhan , Yao Zheng , Lu Mingquan
Published: May 2021

Multi‐path becomes a main source of positioning errors in new‐generation global navigation satellite systems (GNSS). Code multi‐correlator discriminators (MCD), represented by narrow early‐minus‐late (NEML) and double delta (DD) discriminators which are designed for binary phase offset keying (BPSK) signals, are one of the main multi‐path mitigation techniques. However, because of the complicated auto‐correlation function and intricate relationships among multiple correlators, it is hard to implement a trial and error approach, which is the conventional design method of discriminator structures, to specifically design code MCD structures for new GNSS signals which have complicated spreading waveforms. In this article, instead of a trial and error approach, a general design methodology for designing code MCD structures based on heuristic optimisation for multi‐path mitigation is proposed. The proposed method can specifically design code MCD structures for signals with various modulations and receivers with different bandwidths, indicating the adaptability of the proposed method. Multi‐path mitigation performances of such designed structures are better than those of traditional code discriminator structures with strong tracking robustness and slight degradation of thermal noise performance. Designed code MCD structures are also insensitive to multi‐path relative amplitudes and bandwidths of receivers, ensuring the practicality of the designed code MCD structures.
Coverage control of multiple robots in cluttered three‐dimensional environments
Authors: Kim Jonghoek
Published: May 2021

Distributed network systems can be utilized to measure environmental conditions such as temperature, sound, pollution levels, humidity, wind, and so on. Multiple autonomously moving mobile sensors are used to construct distributed sensor networks in an unknown cluttered 3‐D workspace. The proposed strategy is to deploy mobile sensors (robots) sequentially and individually to extend the network until the network fully covers the entire open space. This strategy results in 3‐D sensor networks without sensing holes and does not require global localization of a robot except for a single robot called the Communication Navigation Aid. The authors believe this article is unique in constructing sensor networks in 3‐D workspaces cluttered with many obstacles. Moreover, this article presents an innovative recovery algorithm to handle sensor failures in the constructed network. Network connectivity is maintained while robots move in unknown 3‐D cluttered environments. Once a robot is deployed at its designated location, it becomes localized in global coordinate systems. Utilizing MATLAB, the effectiveness of the proposed deployment methods is demonstrated.
Analysis of hybrid polarization frequency domain spectrum characteristics of oil‐paper insulation transformers
Authors: Zou Yang , He Jin , He Qianlin , Wang Mengqi
Published: May 2021

This paper utilizes a hybrid Debye model to accurately simulate the relaxation response process of the oil‐paper insulation of a transformer to explore the application of frequency domain dielectric spectroscopy (FDS) in nondestructive diagnosis of the aging condition of oil‐paper insulation. Via FDS test data, the model parameters can be identified, and the influence laws of FDS can be obtained through the variation of model parameters. To explore the effects of insulating paper moisture content, insulating paper layers, and test temperature on FDS characteristics, an FDS experimental platform is established. The results show that the hybrid Debye model can effectively reflect the relaxation response process of oil‐paper insulation under different conditions, as well as that a physical relationship between the model parameters and oil‐paper dielectric polarization exists. In addition, the parameters of the hybrid Debye model can be used as the characteristic quantities for the non‐destructive evaluation of the oil‐paper insulation state, providing new ideas for the non‐destructive evaluation of the oil‐paper insulation state.
Aqueous Self-Assembly of Peptide–Diketopyrrolopyrrole Conjugates with Variation of N-Alkyl Side Chain and π-Core Lengths
Authors: Panda Sayak Subhra , Tovar John D.
Published: May 2021

Peptidic sequences when conjugated to π-electronic groups form self-assembled networks of π-electron pathways. These materials hold promise for bio-interfacing charge transporting applications because of their aqueous processability and compatibility. In this work, we incorporated diketopyrrolopyrrole (DPP), a well-established π-core for organic electronic applications, within the peptidic sequence. We embedded different numbers of thiophene rings (2 and 3) on both sides of the DPP to alter the length of the π-cores. We also varied the length of the N-alkyl side chains (methyl, butyl, hexyl) attached to the DPP core. These variations allowed us to explicitly study the effect of π-core and N-alkyl side-chain length on photophysical properties and morphology of the resulting nanomaterials. All of these molecules formed H-type aggregates in the assembled state. Longer π-cores have relatively red-shifted absorption maxima, whereas the N-alkyl variation did not present significant photophysical changes.
CD1a selectively captures endogenous cellular lipids that broadly block T cell response
Authors: Cotton Rachel N. , Wegrecki Marcin , Cheng Tan-Yun , Chen Yi-Ling , Veerapen Natacha , Le Nours Jérôme , Orgill Dennis P. , Pomahac Bohdan , Talbot Simon G. , Willis Richard , Altman John D. , de Jong Annemieke , Van Rhijn Ildiko , Clark Rachael A. , Besra Gurdyal S. , Ogg Graham , Rossjohn Jamie , Moody D. Branch
Published: May 2021

We optimized lipidomics methods to broadly detect endogenous lipids bound to cellular CD1a proteins. Whereas membrane phospholipids dominate in cells, CD1a preferentially captured sphingolipids, especially a C42, doubly unsaturated sphingomyelin (42:2 SM). The natural 42:2 SM but not the more common 34:1 SM blocked CD1a tetramer binding to T cells in all human subjects tested. Thus, cellular CD1a selectively captures a particular endogenous lipid that broadly blocks its binding to TCRs. Crystal structures show that the short cellular SMs stabilized a triad of surface residues to remain flush with CD1a, but the longer lipids forced the phosphocholine group to ride above the display platform to hinder TCR approach. Whereas nearly all models emphasize antigen-mediated T cell activation, we propose that the CD1a system has intrinsic autoreactivity and is negatively regulated by natural endogenous inhibitors selectively bound in its cleft. Further, the detailed chemical structures of natural blockers could guide future design of therapeutic blockers of CD1a response.
Comment on ‘Coincident ion acceleration and electron extraction for space propulsion using the self-bias formed on a set of RF biased grids bounding a plasma source’
Authors: Fu S H , Ding Z F
Published: May 2021

The neutralizer-free ion thruster based on radio frequency (RF) acceleration was proposed as an attractive approach. This comment presents problems arising from such RF acceleration. Two mayor limitations in developing the neutralizer-free RF ion thruster into a practical technology are found to be involved with the grounded grid: (a) the high frequency bias required by low ion impingement from the upstream; (b) serious backstreaming of electron due to the grounded grid that cannot establish a potential barrier. Limitation (a) will degrade the ion production efficiency and cause more serious thermal deformation of the biased grids, especially for large-sized RF ion thrusters. Limitation (b) is the Achilles’ heel of a neutralizer-free RF-biased ion thruster: it in fact operates from the very beginning in the failure mode occurring in the final stage of seriously-eroded DC (direct current) biased ion thruster. The backstreaming electrons will substantially reduce the lifetime of neutralizer-free RF ion thrusters. In the current stage, the RF acceleration is not a promising neutralizer-free technology.
Electronic structure of cubic boron arsenide probed by scanning tunneling spectroscopy
Authors: Lee Hwijong , Gamage Geethal Amila , Lyons John L , Tian Fei , Smith Brandon , Glaser Evan R , Ren Zhifeng , Shi Li
Published: May 2021

The unusually high lattice thermal conductivity of semiconducting cubic boron arsenide (BAs) has motivated studies of the bulk electronic band structure of BAs for its potential use as an active layer material in electronic devices. However, the surface electronic structure of BAs remains to be investigated. Scanning tunneling spectroscopy (STS) is employed here to probe the electronic structure of as-grown and in situ cleaved surfaces of BAs single crystals. The bandgap measured at several interior locations of the cleaved surface is about 2.1 eV, close to our calculated bulk bandgap value of 2.05 eV. In comparison, the measured bandgap within several micrometers from the two edges of the cleaved surface decreases to about 1.9 eV. This decrease is attributed to tunneling from an increased concentration of shallow acceptors. Several of the tunneling peaks observed by STS within the bandgap are close to the calculated energy levels for bulk lattice defects and substitutional impurities. In contrast to some other III–V compound semiconductors where surface relaxation prevents intrinsic surface states from appearing in the bulk bandgap, some measured tunneling peaks in the BAs bulk bandgap can contain contributions from intrinsic surface states calculated for boron dangling bonds.
Permeability of anodic alumina membranes grown on low-index aluminium surfaces
Authors: Roslyakov I V , Petukhov D I , Napolskii K S
Published: May 2021

Porous anodic aluminium oxide (AAO) membranes have various practical applications in separation and purification technologies. Numerous approaches have been utilized to tailor the transport properties of porous AAO films, but all of them assume an isotropic nature of anodized aluminium. Here, the impact of aluminium crystallography on the permeability of AAO membranes is disclosed. A comparative study of AAO membranes formed on low-index aluminium surfaces by anodizing in a sulphuric acid electrolyte is presented. Small-angle x-ray scattering is used to quantify the out-of-plane pore arrangement. AAO grown on an Al(100) substrate possesses a porous structure with minimal point defects and pore tortuosity, providing the highest permeability of individual gases in a series of AAO membranes. These findings can also be applied for the fabrication of highly permeable AAO membranes on polycrystalline Al foils.
Nitrogen fixation in pulsed microwave discharge studied by infrared absorption combined with modelling
Authors: Bahnamiri Omid Samadi , Verheyen Claudia , Snyders Rony , Bogaerts Annemie , Britun Nikolay
Published: May 2021

A pulsed microwave surfaguide discharge operating at 2.45 GHz was used for the conversion of molecular nitrogen into valuable compounds in several gas mixtures: N2:O2, N2:O2:CO2 and N2:CO2. The ro-vibrational absorption bands of the molecular species were monitored by a Fourier transform infrared apparatus in the post-discharge region in order to evaluate the relative number density of species, specifically NO production. The effects of specific energy input, pulse frequency, gas flow fraction, gas admixture and gas flow rate were studied for better understanding and optimization of the NO production yield and the corresponding energy cost (EC). By both the experiment and modelling, a highest NO yield is obtained at N2:O2 (1:1) gas ratio in N2:O2 mixture. The NO yield reveals a small growth followed by saturation when pulse repetition frequency increases. The energy efficiency start decreasing after the energy input reaches about 5 eV/molec, whereas the NO yield rises steadily at the same time. The lowest EC of about 8 MJ mol−1 corresponding to the yield and the energy efficiency of about 7% and 1% are found, respectively, in an optimum discharge condition in our case.