bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and direct assay of large macrocycle diversities by combinatorial late-stage modification at picomole scale
Authors: Habeshian Sevan , Merz Manuel Leonardo , Sangouard Gontran , Mothukuri Ganesh Kumar , Schüttel Mischa , Bognár Zsolt , Díaz-Perlas Cristina , Vesin Jonathan , Bortoli Chapalay Julien , Turcatti Gerardo , Cendron Laura , Angelini Alessandro , Heinis Christian
Published: July 2022

Macrocycles have excellent potential as therapeutics due to their ability to bind challenging targets. However, generating macrocycles against new targets is hindered by a lack of large macrocycle libraries for high-throughput screening. To overcome this, we herein established a combinatorial approach by tethering a myriad of chemical fragments to peripheral groups of structurally diverse macrocyclic scaffolds in a combinatorial fashion, all at a picomole scale in nanoliter volumes using acoustic droplet ejection technology. In a proof-of-concept, we generate a target-tailored library of 19,968 macrocycles by conjugating 104 carboxylic-acid fragments to 192 macrocyclic scaffolds. The high reaction efficiency and small number of side products of the acylation reactions allowed direct assay without purification and thus a large throughput. In screens, we identify nanomolar inhibitors against thrombin (Ki = 44 ± 1 nM) and the MDM2:p53 protein-protein interaction (Kd MDM2 = 43 ± 18 nM). The increased efficiency of macrocycle synthesis and screening and general applicability of this approach unlocks possibilities for generating leads against any protein target.
Electroredox carbene organocatalysis with iodide as promoter
Authors: Zhou Peng , Li Wenchang , Lan Jianyong , Zhu Tingshun
Published: July 2022

Oxidative carbene organocatalysis, inspired from Vitamin B1 catalyzed oxidative activation from pyruvate to acetyl coenzyme A, have been developed as a versatile synthetic method. To date, the α-, β-, γ-, δ- and carbonyl carbons of (unsaturated)aldehydes have been successfully activated via oxidative N-heterocyclic carbene (NHC) organocatalysis. In comparison with chemical redox or photoredox methods, electroredox methods, although widely used in mechanistic study, were much less developed in NHC catalyzed organic synthesis. Herein, an iodide promoted electroredox NHC organocatalysis system was developed. This system provided general solutions for electrochemical single-electron-transfer (SET) oxidation of Breslow intermediate towards versatile transformations. Radical clock experiment and cyclic voltammetry results suggested an anodic radical coupling pathway.
Single-molecule FRET uncovers hidden conformations and dynamics of human Argonaute 2
Authors: Willkomm Sarah , Jakob Leonhard , Kramm Kevin , Graus Veronika , Neumeier Julia , Meister Gunter , Grohmann Dina
Published: July 2022

Human Argonaute 2 (hAgo2) constitutes the functional core of the RNA interference pathway. Guide RNAs direct hAgo2 to target mRNAs, which ultimately leads to hAgo2-mediated mRNA degradation or translational inhibition. Here, we combine site-specifically labeled hAgo2 with time-resolved single-molecule FRET measurements to monitor conformational states and dynamics of hAgo2 and hAgo2-RNA complexes in solution that remained elusive so far. We observe dynamic anchoring and release of the guide’s 3’-end from the PAZ domain during the stepwise target loading process even with a fully complementary target. We find differences in structure and dynamic behavior between partially and fully paired canonical hAgo2-guide/target complexes and the miRNA processing complex formed by hAgo2 and pre-miRNA451. Furthermore, we detect a hitherto unknown conformation of hAgo2-guide/target complexes that poises them for target-directed miRNA degradation. Taken together, our results show how the conformational flexibility of hAgo2-RNA complexes determines function and the fate of the ribonucleoprotein particle.
The megabase-scale crossover landscape is largely independent of sequence divergence
Authors: Lian Qichao , Solier Victor , Walkemeier Birgit , Durand Stéphanie , Huettel Bruno , Schneeberger Korbinian , Mercier Raphael
Published: July 2022

Meiotic recombination frequency varies along chromosomes and strongly correlates with sequence divergence. However, the causal relationship between recombination landscapes and polymorphisms is unclear. Here, we characterize the genome-wide recombination landscape in the quasi-absence of polymorphisms, usingArabidopsis thalianahomozygous inbred lines in which a few hundred genetic markers were introduced through mutagenesis. We find that megabase-scale recombination landscapes in inbred lines are strikingly similar to the recombination landscapes in hybrids, with the notable exception of heterozygous large rearrangements where recombination is prevented locally. In addition, the megabase-scale recombination landscape can be largely explained by chromatin features. Our results show that polymorphisms are not a major determinant of the shape of the megabase-scale recombination landscape but rather favour alternative models in which recombination and chromatin shape sequence divergence across the genome.
Green gentrification in European and North American cities
Authors: Anguelovski Isabelle , Connolly James J. T. , Cole Helen , Garcia-Lamarca Melissa , Triguero-Mas Margarita , Baró Francesc , Martin Nicholas , Conesa David , Shokry Galia , del Pulgar Carmen Pérez , Ramos Lucia Argüelles , Matheney Austin , Gallez Elsa , Oscilowicz Emilia , Máñez Jésua López , Sarzo Blanca , Beltrán Miguel Angel , Minaya Joaquin Martinez
Published: July 2022

Although urban greening is universally recognized as an essential part of sustainable and climate-responsive cities, a growing literature on green gentrification argues that new green infrastructure, and greenspace in particular, can contribute to gentrification, thus creating social and racial inequalities in access to the benefits of greenspace and further environmental and climate injustice. In response to limited quantitative evidence documenting the temporal relationship between new greenspaces and gentrification across entire cities, let alone across various international contexts, we employ a spatially weighted Bayesian model to test the green gentrification hypothesis across 28 cities in 9 countries in North America and Europe. Here we show a strong positive and relevant relationship for at least one decade between greening in the 1990s–2000s and gentrification that occurred between 2000–2016 in 17 of the 28 cities. Our results also determine whether greening plays a “lead”, “integrated”, or “subsidiary” role in explaining gentrification.
An in situ hydrogel-mediated chemo-immunometabolic cancer therapy
Authors: Wang Bo , Chen Jing , Caserto Julia S. , Wang Xi , Ma Minglin
Published: July 2022

Metabolic reprogramming of the tumor microenvironment (TME) and poor immunogenicity are two of the challenges that cancer immunotherapies have to overcome for improved clinical benefits. Among various immunosuppressive metabolites that keep anti-tumor immunity in check, the tryptophan catabolite kynurenine (Kyn) is an attractive target for blockade given its role in mediating immunosuppression through multiple pathways. Here, we present a local chemo-immunometabolic therapy through injection of a supramolecular hydrogel concurrently releasing doxorubicin that induces immunogenic tumor cell death and kynureninase that disrupts Kyn-mediated immunosuppressive pathways in TME. The combination synergically enhances tumor immunogenicity and unleashes anti-tumor immunity. In mouse models of triple negative breast cancer and melanoma, a single low dose peritumoral injection of the therapeutic hydrogel promotes TME transformation toward more immunostimulatory, which leads to enhanced tumor suppression and extended mouse survival. In addition, the systemic anti-tumor surveillance induced by the local treatment exhibits an abscopal effect and prevents tumor relapse post-resection. This versatile approach for local chemo-immunometabolic therapy may serve as a general strategy for enhancing anti-tumor immunity and boosting the efficacy of cancer immunotherapies.
Resilience of S309 and AZD7442 monoclonal antibody treatments against infection by SARS-CoV-2 Omicron lineage strains
Authors: Case James Brett , Mackin Samantha , Errico John M. , Chong Zhenlu , Madden Emily A. , Whitener Bradley , Guarino Barbara , Schmid Michael A. , Rosenthal Kim , Ren Kuishu , Dang Ha V. , Snell Gyorgy , Jung Ana , Droit Lindsay , Handley Scott A. , Halfmann Peter J. , Kawaoka Yoshihiro , Crowe James E. , Fremont Daved H. , Virgin Herbert W. , Loo Yueh-Ming , Esser Mark T. , Purcell Lisa A. , Corti Davide , Diamond Michael S.
Published: July 2022

Omicron variant strains encode large numbers of changes in the spike protein compared to historical SARS-CoV-2 isolates. Although in vitro studies have suggested that several monoclonal antibody therapies lose neutralizing activity against Omicron variants, the effects in vivo remain largely unknown. Here, we report on the protective efficacy against three SARS-CoV-2 Omicron lineage strains (BA.1, BA.1.1, and BA.2) of two monoclonal antibody therapeutics (S309 [Vir Biotechnology] monotherapy and AZD7442 [AstraZeneca] combination), which correspond to ones used to treat or prevent SARS-CoV-2 infections in humans. Despite losses in neutralization potency in cell culture, S309 or AZD7442 treatments reduced BA.1, BA.1.1, and BA.2 lung infection in susceptible mice that express human ACE2 (K18-hACE2) in prophylactic and therapeutic settings. Correlation analyses between in vitro neutralizing activity and reductions in viral burden in K18-hACE2 or human FcγR transgenic mice suggest that S309 and AZD7442 have different mechanisms of protection against Omicron variants, with S309 utilizing Fc effector function interactions and AZD7442 acting principally by direct neutralization. Our data in mice demonstrate the resilience of S309 and AZD7442 mAbs against emerging SARS-CoV-2 variant strains and provide insight into the relationship between loss of antibody neutralization potency and retained protection in vivo.
Rapid northern hemisphere ice sheet melting during the penultimate deglaciation
Authors: Stoll Heather M. , Cacho Isabel , Gasson Edward , Sliwinski Jakub , Kost Oliver , Moreno Ana , Iglesias Miguel , Torner Judit , Perez-Mejias Carlos , Haghipour Negar , Cheng Hai , Edwards R. Lawrence
Published: July 2022

The rate and consequences of future high latitude ice sheet retreat remain a major concern given ongoing anthropogenic warming. Here, new precisely dated stalagmite data from NW Iberia provide the first direct, high-resolution records of periods of rapid melting of Northern Hemisphere ice sheets during the penultimate deglaciation. These records reveal the penultimate deglaciation initiated with rapid century-scale meltwater pulses which subsequently trigger abrupt coolings of air temperature in NW Iberia consistent with freshwater-induced AMOC slowdowns. The first of these AMOC slowdowns, 600-year duration, was shorter than Heinrich 1 of the last deglaciation. Although similar insolation forcing initiated the last two deglaciations, the more rapid and sustained rate of freshening in the eastern North Atlantic penultimate deglaciation likely reflects a larger volume of ice stored in the marine-based Eurasian Ice sheet during the penultimate glacial in contrast to the land-based ice sheet on North America as during the last glacial.
The different prognostic significance of polysialic acid and CD56 expression in tumor cells and lymphocytes identified in breast cancer
Authors: Soukhtehzari Sepideh , Berish Richard B. , Fazli Ladan , Watson Peter H. , Williams Karla C.
Published: July 2022

Protein glycosylation, the attachment of carbohydrates onto proteins, is a fundamental process that alters the biological activity of proteins. Changes to glycosylation states are associated with many forms of cancer including breast cancer. Through immunohistological analysis of breast cancer patient tumors, we have discovered the expression of an atypical glycan—polysialic acid (polySia)—in breast cancer. Notably, we have identified polySia expression in not only tumor cells but also on tumor-infiltrating lymphocytes (TILs) and our study reveals ST8Sia4 as the predominant polysialyltransferase expressed. Evaluation of ST8Sia4 expression in tumor cells identified an association between high expression levels and poor patient outcomes whereas ST8Sia4 expression in infiltrating stromal cells was associated with good patient outcomes. Investigation into CD56, a protein known to be polysialylated, found CD56 and polySia expression on breast tumor cells and TILs. CD56 expression did not positively correlate with polySia expression except in patient tumors which expressed HER2. In these HER2 expressing tumors, CD56 expression was significantly associated with HER2 expression score. Evaluation of CD56 tumor cell expression identified a significant association between CD56 expression and poor patient outcomes. By contrast, CD56 expression on TILs was significantly associated with good clinical outcomes. Tumors with CD56+ TILs were also consistently polySia TIL positive. Interestingly, in tumors where TILs were CD56 low-to-negative, a polySia+ lymphocyte population was still identified and the presence of these lymphocytes was a poor prognostic indicator. Overall, this study provides the first detailed report of polySia and CD56 in breast cancer and demonstrates that the prognostic significance is dependent on the cell type expression within the tumor.
Effects of different inspiratory muscle warm-up loads on mechanical, physiological and muscle oxygenation responses during high-intensity running and recovery
Authors: Marostegan Anita B. , Gobatto Claudio A. , Rasteiro Felipe M. , Hartz Charlini S. , Moreno Marlene A. , Manchado-Gobatto Fúlvia B.
Published: July 2022

Inspiratory muscle warm-up (IMW) has been used as a resource to enhance exercises and sports performance. However, there is a lack of studies in the literature addressing the effects of different IMW loads (especially in combination with a shorter and applicable protocol) on high-intensity running and recovery phase. Thus, this study aimed to investigate the effects of three different IMW loads using a shorter protocol on mechanical, physiological and muscle oxygenation responses during and after high-intensity running exercise. Sixteen physically active men, randomly performed four trials 30 s all-out run, preceded by the shorter IMW protocol (2 × 15 breaths with a 1-min rest interval between sets, accomplished 2 min before the 30 s all-out run). Here, three IMW load conditions were used: 15%, 40%, and 60% of maximal inspiratory pressure (MIP), plus a control session (CON) without the IMW. The force, velocity and running power were measured (1000 Hz). Two near-infrared spectroscopy (NIRS) devices measured (10 Hz) the muscle’s oxygenation responses in biceps brachii (BB) and vastus lateralis (VL). Additionally, heart rate (HR) and blood lactate ([Lac]) were also monitored. IMW loads applied with a shorter protocol promoted a significant increase in mean and minimum running power as well as in peak and minimum force compared to CON. In addition, specific IMW loads led to higher values of peak power, mean velocity (60% of MIP) and mean force (40 and 60% of MIP) in relation to CON. Physiological responses (HR and muscles oxygenation) were not modified by any IMW during exercise, as well as HR and [Lac] in the recovery phase. On the other hand, 40% of MIP presented a higher tissue saturation index (TSI) for BB during recovery phase. In conclusion, the use of different loads of IMW may improve the performance of a physically active individual in a 30 s all-out run, as verified by the increased peak, mean and minimum mechanical values, but not in performance assessed second by second. In addition, 40% of the MIP improves TSI of the BB during the recovery phase, which can indicate greater availability of O2 for lactate clearance.
Predicting high recombinant protein producer strains of Pichia pastoris MutS using the oxygen transfer rate as an indicator of metabolic burden
Authors: Wollborn David , Munkler Lara Pauline , Horstmann Rebekka , Germer Andrea , Blank Lars Mathias , Büchs Jochen
Published: July 2022

The methylotrophic yeast Pichia pastoris (Komagataella phaffii) is a widely used host for recombinant protein production. In this study, a clonal library of P. pastoris MutS strains (S indicates slow methanol utilization) was screened for high green fluorescent protein (GFP) production. The expression cassette was under the control of the methanol inducible AOX promoter. The growth behavior was online-monitored in 48-well and 96-well microtiter plates by measuring the oxygen transfer rate (OTR). By comparing the different GFP producing strains, a correlation was established between the slope of the cumulative oxygen transfer during the methanol metabolization phase and the strain’s production performance. The correlation corresponds to metabolic burden during methanol induction. The findings were validated using a pre-selected strain library (7 strains) of high, medium, and low GFP producers. For those strains, the gene copy number was determined via Whole Genome Sequencing. The results were consistent with the described OTR correlation. Additionally, a larger clone library (45 strains) was tested to validate the applicability of the proposed method. The results from this study suggest that the cumulative oxygen transfer can be used as a screening criterion for protein production performance that allows for a simple primary screening process, facilitating the pre-selection of high producing strains.
Automated methodology for optimal selection of minimum electrode subsets for accurate EEG source estimation based on Genetic Algorithm optimization
Authors: Soler Andres , Moctezuma Luis Alfredo , Giraldo Eduardo , Molinas Marta
Published: July 2022

High-density Electroencephalography (HD-EEG) has proven to be the EEG montage that estimates the neural activity inside the brain with highest accuracy. Multiple studies have reported the effect of electrode number on source localization for specific sources and specific electrode configurations. The electrodes for these configurations are often manually selected to uniformly cover the entire head, going from 32 to 128 electrodes, but electrode configurations are not often selected according to their contribution to estimation accuracy. In this work, an optimization-based study is proposed to determine the minimum number of electrodes that can be used and to identify the optimal combinations of electrodes that can retain the localization accuracy of HD-EEG reconstructions. This optimization approach incorporates scalp landmark positions of widely used EEG montages. In this way, a systematic search for the minimum electrode subset is performed for single- and multiple-source localization problems. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) combined with source reconstruction methods is used to formulate a multi-objective optimization problem that concurrently minimizes (1) the localization error for each source and (2) the number of required EEG electrodes. The method can be used for evaluating the source localization quality of low-density EEG systems (e.g. consumer-grade wearable EEG). We performed an evaluation over synthetic and real EEG datasets with known ground-truth. The experimental results show that optimal subsets with 6 electrodes can attain an equal or better accuracy than HD-EEG (with more than 200 channels) for a single source case. This happened when reconstructing a particular brain activity in more than 88% of the cases in synthetic signals and 63% in real signals, and in more than 88% and 73% of cases when considering optimal combinations with 8 channels. For a multiple-source case of three sources (only with synthetic signals), it was found that optimized combinations of 8, 12 and 16 electrodes attained an equal or better accuracy than HD-EEG with 231 electrodes in at least 58%, 76%, and 82% of cases respectively. Additionally, for such electrode numbers, lower mean errors and standard deviations than with 231 electrodes were obtained.
Genome doubling enabled the expansion of yeast vesicle traffic pathways
Authors: Purkanti Ramya , Thattai Mukund
Published: July 2022

Vesicle budding and fusion in eukaryotes depend on a suite of protein types, such as Arfs, Rabs, coats and SNAREs. Distinct paralogs of these proteins act at distinct intracellular locations, suggesting a link between gene duplication and the expansion of vesicle traffic pathways. Genome doubling, a common source of paralogous genes in fungi, provides an ideal setting in which to explore this link. Here we trace the fates of paralog doublets derived from the 100-Ma-old hybridization event that gave rise to the whole genome duplication clade of budding yeast. We find that paralog doublets involved in specific vesicle traffic functions and pathways are convergently retained across the entire clade. Vesicle coats and adaptors involved in secretory and early-endocytic pathways are retained as doublets, at rates several-fold higher than expected by chance. Proteins involved in later endocytic steps and intra-Golgi traffic, including the entire set of multi-subunit and coiled-coil tethers, have reverted to singletons. These patterns demonstrate that selection has acted to expand and diversify the yeast vesicle traffic apparatus, across species and time.
CRISPR/Cas9-based genome-wide screening of Dictyostelium
Authors: Ogasawara Takanori , Watanabe Jun , Adachi Remi , Ono Yusuke , Kamimura Yoichiro , Muramoto Tetsuya
Published: July 2022

Genome-wide screening is powerful method used to identify genes and pathways associated with a phenotype of interest. The simple eukaryote Dictyostelium discoideum has a unique life cycle and is often used as a crucial research model for a wide range of biological processes and rare metabolites. To address the inadequacies of conventional genetic screening approaches, we developed a highly efficient CRISPR/Cas9-based genome-wide screening system for Dictyostelium. A genome-wide library of 27,405 gRNAs and a kinase library of 4,582 gRNAs were compiled and mutant pools were generated. The resulting mutants were screened for defects in cell growth and more than 10 candidate genes were identified. Six of these were validated and five recreated mutants presented with growth abnormalities. Finally, the genes implicated in developmental defects were screened to identify the unknown genes associated with a phenotype of interest. These findings demonstrate the potential of the CRISPR/Cas9 system as an efficient genome-wide screening method.
Protein–protein interaction and non-interaction predictions using gene sequence natural vector
Authors: Zhao Nan , Zhuo Maji , Tian Kun , Gong Xinqi
Published: July 2022

Predicting protein–protein interaction and non-interaction are two important different aspects of multi-body structure predictions, which provide vital information about protein function. Some computational methods have recently been developed to complement experimental methods, but still cannot effectively detect real non-interacting protein pairs. We proposed a gene sequence-based method, named NVDT (Natural Vector combine with Dinucleotide and Triplet nucleotide), for the prediction of interaction and non-interaction. For protein–protein non-interactions (PPNIs), the proposed method obtained accuracies of 86.23% for Homo sapiens and 85.34% for Mus musculus, and it performed well on three types of non-interaction networks. For protein-protein interactions (PPIs), we obtained accuracies of 99.20, 94.94, 98.56, 95.41, and 94.83% for Saccharomyces cerevisiae, Drosophila melanogaster, Helicobacter pylori, Homo sapiens, and Mus musculus, respectively. Furthermore, NVDT outperformed established sequence-based methods and demonstrated high prediction results for cross-species interactions. NVDT is expected to be an effective approach for predicting PPIs and PPNIs.
A previous hemorrhagic stroke protects against a subsequent stroke via microglia alternative polarization
Authors: Lee Shin-Shin , Pang Li , Cheng Yin , Liu Jia Xin , Ng Anson Cho Kiu , Leung Gilberto Ka Kit
Published: July 2022

Microglia in hemorrhagic stroke contribute to both acute-phase exacerbation and late-phase attenuation of injury. Here, by using the mouse model, we reported that the shift in polarization of microglia from M1 to M2 phenotype could be altered by a past ‘mini’ stroke, resulting in better neurological function recovery, faster attenuation of lesion volume, and better survival. In mice with a previous stroke, M2 predominance appeared markedly in advance compared to mice without a previous stroke. Mechanistically, the RBC-mediated M2 polarization of microglia was synergistically enhanced by T cells: microglia cocultured with RBCs alone resulted in mild alterations to M2 markers, whereas in the presence of T cells, they expressed an early and sustained M2 response. These results suggest that by harnessing the microglia-mediated M2 polarization response, we could help mitigate devastating sequelae before a prospective hemorrhagic stroke even happens.
A dual-targeting peptide facilitates targeting anti-inflammation to attenuate atherosclerosis in ApoE−/− mice
Authors: Wu Bo , Zhong Yuanzhi , Chen Jinmin , Pan Xianmei , Fan Xianglin , Chen Peier , Fu Chenxing , Ou Caiwen , Chen Minsheng
Published: July 2022

A dual-targeting peptide towards inflamed endothelial cells is reported, which improves the antiatherogenic effect of anti-inflammatory drug puerarin.
A microporous Zr6@Zr-MOF for the separation of Xe and Kr
Authors: Guo Fu-An , Zhou Kang , Liu Jiaqi , Li Xingyu , Wang Hao
Published: July 2022

A microporous Zr6@Zr-MOF has been synthesized and characterized, which features the 4,6-c she topology with discrete hexanuclear Zr-oxo clusters residing at the pore windows. It displays selective adsorption of Xe over Kr.
Successive constructions of regular tetra-, hexa- and octanuclear microporous polyoxovanadates(iii) for gas adsorption
Authors: Xie Zhen-Lang , An Dong-Li , Weng Wei-Zheng , Zhou Zhao-Hui
Published: July 2022

Regular tetra-, hexa- and octanuclear microporous polyoxovanadates(iii) 1–4 are constructed successively. An interesting isolated intrinsic POMOF 4 with the functionalization of microchannels exhibits a notable affinity toward CO2 adsorption.
What is the best scenario to utilize landfill gas? Quantitative and qualitative approaches for technical, economic, and environmental feasibility
Authors: Byun Manhee , Kim Heehyang , Lee Aejin , Cheon Seunghyun , Gu Jiwon , Lim Hankwon
Published: July 2022

The feasibility study in technical, economic, and environmental aspects was performed for various landfill gas utilization scenarios: Hydrogen, electricity, methanol, formic acid, and dimethyl ether production.
A novel flame-resistant separator for high performance lithium–sulfur batteries
Authors: Wang Jianyi , Chen Menghui , Qin Weiwei , Zhou Meng
Published: July 2022

An optimized separator for deployment in Li–S batteries based on oxygen vacancy (OV)-rich BaTiO3 is presented that offers operational stability at elevated temperatures (60 °C) with high performance.
Meter-scale chemiluminescent carbon nanodot films for temperature imaging
Authors: Zheng Guang-Song , Shen Cheng-Long , Lou Qing , Han Jiang-Fan , Ding Zhong-Zheng , Deng Yuan , Wu Meng-Yuan , Liu Kai-Kai , Zang Jin-Hao , Dong Lin , Shan Chong-Xin
Published: July 2022

Meter-scale chemiluminescent carbon nanodot films have been constructed with outstanding thermographic sensitivity, being compatible with non-planar palm thermal imaging.
Remarkably enhanced dynamic oxygen migration on graphene oxide supported by copper substrate
Authors: Yan Zihan , Yang Wenjie , Yang Hao , Ji Chengao , Zeng Shuming , Zhang Xiuyun , Zhao Liang , Tu Yusong
Published: July 2022

Graphene oxide can become a dynamic covalent material when supported by a copper substrate; oxygen groups can migrate along the basal plane of GO via C–O bond breaking/reforming reactions and proton transfer to neighboring hydroxyl groups.
Lightweight electromagnetic wave absorbent composites with Fe3O4 nanocrystals uniformly decorated on the surface of carbon spheres
Authors: Dai Bushi , Qi Tao , Song Mengjie , Geng Mingqian , Dai Yuxiang , Qi Yang
Published: July 2022

The application of electromagnetic waves has reached every aspect of human life, but the search for superior electromagnetic wave absorbent materials has been a constant quest of researchers.
Surface hydroxyl groups: the key to a CrOx/TiO2 catalyst for efficient catalytic oxidation of 2,2′-hydrazine diisobutyronitrile
Authors: Zhang Hu , Zou Xingli , Wang Xueguang , Xie Haijiao , Jiao Zheng , Lu Xionggang
Published: July 2022

Surface hydroxyl groups could contribute to the formation of Cr–O–Ti bonds on the surface of the CrOx/TiO2 catalyst, which thus promote the oxidation of 2,2′-hydrazobis-isobutyronitrile.
Mesoporous hollow Fe3O4 nanoparticles regulate the behavior of neuro-associated cells through induction of macrophage polarization in an alternating magnetic field
Authors: Guo Weiru , Wu Xiaopei , Wei Wenying , Wang Youfa , Dai Honglian
Published: July 2022

The MHFPs prepared in this study, in collaboration with AMF, were internalized by macrophages. This regulated the M2 polarization of macrophages, which ultimately affected the behavior of neuro-associated cells.
Improved linear cryptanalysis on 25‐round SMS4
Authors: Fu Lishi , Jin Chenhui
Published: July 2022

SMS4 is the Chinese national standard for WLAN, which is also an ISO/IEC international standard. This paper presents a linear cryptanalysis on 25‐round SMS4 for the first time. Firstly, this paper adopts a new statistic in linear cryptanalysis, which is aimed to compute the distance between one cipher system and one random permutation, which can be used to distinguish the right key from the wrong keys by the different probability distributions they follow. Secondly, the attack principal and data complexity are given when this new statistic is used in multiple linear cryptanalysis. Thirdly, this paper presents 21‐round linear approximations with absolute correlation by fixing the least significant input bit of the Sbox with nonzero mask in the first round to be 1. Furthermore, this paper gives 48 21‐round linear approximations with absolute correlation . Based on the restrictions between those 48 linear approximations and fast Fourier transformation technique, the whole attack needs known plaintexts, 25‐round SMS4 encryptions along with memory accesses, and bytes of memory, which is the best cryptanalysis result on SMS4 so far. Finally, this paper generalizes the linear cryptanalysis method with conditioned linear approximation, which can also be adopted in attacking other ciphers.
Robust linear unmixing with enhanced constraint of classification for hyperspectral remote sensing imagery
Authors: Yu Haoyang , Chi Jinxue , Shang Xiaodi , Shen Xueji , Chanussot Jocelyn , Shi Yimin
Published: July 2022

Although hyperspectral data, especially spaceborne images, are rich in spectral information, their spatial resolution is usually low due to the limitation of sensor design and other factors. Therefore, for the application of hyperspectral images, unmixing technology is a key processing technology, such as linear mixing model and its derived algorithms have made a certain progress. However, a real scene often contains both pure and mixed pixels. The existing methods usually ignore the consideration and analysis of this situation in the process of model design and simulation experiment. In this context, this paper proposes a robust linear unmixing model with the enhanced constraint of classification for hyperspectral image. In general, it designs a framework combining unmixing and classification. In the task for real scene data, endmembers are extracted first, and then the hard classification term constructed after the expansion of endmembers (training samples) based on similarity is introduced to provide the sparsity constraint of the overall model, so as to realize relatively complete adjustment and effective image unmixing under complex conditions. Considering the scene with different distributions, the simulation experiment designs several groups of data tests, including different proportions of pure and mixing pixels. The unmixing results of three simulated datasets and two real datasets show that the unmixing results of this method are better than those of the other six comparison methods. This model improves the accuracy of unmixing and realizes effective unmixing.
Automatic emergency braking/anti‐lock braking system coordinated control with road adhesion coefficient estimation for heavy vehicle
Authors: Shaohua Li , Guiyang Wang , Hesen Wang , Lipeng Zhang
Published: July 2022

The road adhesion coefficient is a key factor influencing automatic emergency braking (AEB) and anti‐lock braking system (ABS) safety control of trucks. With the fading factor introduced, and the covariance gain adjusted in real time, the strong tracking unscented Kalman filter (STUKF) algorithm is modified to estimate the road adhesion coefficient more accurately. Composed of an ABS fuzzy sliding mode controller (SMC) and an AEB controller, an AEB/ABS coordinated control strategy with an adhesion coefficient estimation is designed for a three‐axle heavy vehicle. The control effects are verified through experiments on various road conditions based on a hardware‐in‐loop test platform. The test results show that the proposed control strategy has a better braking efficiency than the traditional AEB/ABS and AEB control strategy without adhesion coefficient estimation and can decrease braking distance by 8.4% and braking time by 5.9%, which is beneficial to the vehicle longitudinal safety.
Study on the local and global performance of homogeneous platoon with a bidirectional ring interconnection
Authors: Zhang Junying , Ma Xindi
Published: July 2022

This paper investigates the local and global performance of the platoon where multiple identical vehicles move in a closed roadway and cooperate based on nearest‐neighbour interactions. The information from the front neighbour, namely position, speed, and acceleration, is weighted non‐equally component‐wise to that from the back neighbour, which is quantified by the asymmetry level on each component. The local performance refers to the locally propagating attenuation for the bidirectional control, which captures whether the disturbance is amplified when propagating from a vehicle to its immediate neighbours. The global performance refers to the system transfer scalability, which characterises the scalability of system transfer matrix. Based on forward and backward wave transfer functions, several analytical necessary conditions of the locally propagating attenuation are obtained. Furthermore, two of these necessary conditions happen to be the same with the conditions for scalably asymptotic stability. Under mild assumptions, the locally propagating attenuation is sufficient for scalably asymptotic stability, the latter of which in turn implies the system transfer scalability. Numerical calculations further show that it is favourable for both performance measures to select the asymmetry levels on speed and acceleration with small magnitudes and located around the centre line of the band‐like region of scalably asymptotic stability.
On the scaling of three-dimensional shock-induced separated flow due to protuberances
Authors: Bhardwaj S. , Hemanth Chandra Vamsi K. , Sriram R.
Published: July 2022

Supersonic flow over three-dimensional bodies protruding out of the turbulent boundary layer was investigated by means of experiments and numerical computations. A parametric study was performed by varying the shape and dimensions of the protuberance, as well as the freestream Mach numbers (1.5, 2, 2.5, 2.89, and 3.5). Surface streak line visualization, surface pressure measurements, and time-resolved Schlieren visualization were employed along with Reynolds-averaged Navier–Stokes computations to elicit the complex flow features such as the separation line, shock pattern, and the horseshoe vortex, which greatly influence the flow dynamics in the separated region. The rise in surface pressure at mid-span due to separation (plateau pressure) was dependent only on the incoming flow parameters and independent of protuberance geometry. The two-dimensional free interaction theory, applied for normal shock-induced separation, closely predicts the mid-span plateau pressure. Although protuberances are of varying shapes and dimensions, the inviscid bow shock (obtained from Euler computations) provided generalized scales, whose effects on shock boundary layer interactions are analyzed. The radius of curvature of the inviscid shock on the wall plane at the nose, which is theoretically related to the local second derivative (along the shock) of pressure jump, was found to be a determining parameter of mid-span separation length (Lsep). Since the spanwise distance of the sonic point on the inviscid shock was found to be strongly correlated with its nose radius of curvature, it follows that the “strong” portion of the inviscid bow shock fixes the mid-span separation location. These observations concerning mid-span plateau pressure, and the role of strong shock portion in fixing mid-span separation, suggest that the Lsep shall be predicted from a modification of the scaling laws for the length of plateau pressure region in two-dimensional shock boundary layer interaction, with the inclusion of a spanwise relieving effect. A correlation is obtained relating the Lsep with various incoming flow parameters and inviscid shock nose radius. The mid-span vortex core position was found to be linearly related to the Lsep. The radius of curvature of the separation shock is, however, found to be influenced by the entire inviscid shock, including the “weak” portion.
Jetting axial flow induced by nanosecond repetitively pulsed discharges in quiescent ambient air
Authors: Shcherbanev Sergey A , Krzymuski Tanguy , Xiong Yuan , Noiray Nicolas
Published: July 2022

This study investigates the phenomenon of jetting axial flow induced by nanosecond repetitively pulsed discharges (NRPD) in quiescent ambient air in a pin-to-pin electrode configuration. Axial stratification of discharge parameters (electron number density, temperature, specific energy, etc) influences the hydrodynamic effects leading to directed gas flow from the cathode towards the anode. The experimental results presented in this paper were obtained using schlieren imaging, optical emission spectroscopy (OES), and electrical measurements of the deposited energy. A jetting axial flow was induced for all considered gap distances (0.5–5 mm) and pulse repetition frequencies of

⩾

10 kHz. The direction of the induced flow is defined by the polarity of the applied high-voltage pulses. It was found that the flow does not arise immediately after the initiation of the first pulse of the applied burst but is induced after a certain number of pulses. Using temporally and spatially resolved OES the electron densities and temperatures were measured in the vicinity of the cathode and anode before and after the generation of the axial flow. A model explaining the generation and maintenance of the axial flow in NRPD and the role of the inhomogeneities of plasma parameters along the plasma channel on hydrodynamic effects is suggested and discussed.
Freestanding complex-oxide membranes
Authors: Pesquera David , Fernández Abel , Khestanova Ekaterina , Martin Lane W
Published: July 2022

Complex oxides show a vast range of functional responses, unparalleled within the inorganic solids realm, making them promising materials for applications as varied as next-generation field-effect transistors, spintronic devices, electro-optic modulators, pyroelectric detectors, or oxygen reduction catalysts. Their stability in ambient conditions, chemical versatility, and large susceptibility to minute structural and electronic modifications make them ideal subjects of study to discover emergent phenomena and to generate novel functionalities for next-generation devices. Recent advances in the synthesis of single-crystal, freestanding complex oxide membranes provide an unprecedented opportunity to study these materials in a nearly-ideal system (e.g. free of mechanical/thermal interaction with substrates) as well as expanding the range of tools for tweaking their order parameters (i.e. (anti-)ferromagnetic, (anti-)ferroelectric, ferroelastic), and increasing the possibility of achieving novel heterointegration approaches (including interfacing dissimilar materials) by avoiding the chemical, structural, or thermal constraints in synthesis processes. Here, we review the recent developments in the fabrication and characterization of complex-oxide membranes and discuss their potential for unraveling novel physicochemical phenomena at the nanoscale and for further exploiting their functionalities in technologically relevant devices.
Superconducting niobium nitride: a perspective from processing, microstructure, and superconducting property for single photon detectors
Authors: Cucciniello Nicholas , Lee Derek , Feng Henry Y , Yang Zihao , Zeng Hao , Patibandla Nag , Zhu Mingwei , Jia Quanxi
Published: July 2022

Superconducting niobium nitride (NbN) continues to be investigated decades on, largely in part to its advantageous superconducting properties and wide use in superconducting electronics. Particularly, NbN-based superconducting nanowire single-photon detectors (SNSPDs) have shown exceptional performance and NbN remains as the material of choice in developing future generation quantum devices. In this perspective, we describe the processing–structure–property relationships governing the superconducting properties of NbN films. We further discuss the complex interplay between the material properties, processing parameters, substrate materials, device architectures, and performance of SNSPDs. We also highlight the latest progress in optimizing SNSPD performance parameters.
Tuning the nonlinearity of graphene mechanical resonators by Joule heating
Authors: Suo Jiao-Jiao , Li Wei-Jie , Cheng Ze-Di , Zhao Zi-Fan , Chen Hui , Li Bo-Lin , Zhou Qiang , Wang You , Song Hai-Zhi , Niu Xiao-Bin , Deng Guang-Wei
Published: July 2022

As an inherent property of the device itself, nonlinearity in micro-/nano- electromechanical resonators is difficult to eliminate, and it has shown a wide range of applications in basic research, sensing and other fields. While many application scenarios require tunability of the nonlinearity, inherent nonlinearity of a mechanical resonator is difficult to be changed. Here, we report the experimental observation of a Joule heating induced tuning effect on the nonlinearity of graphene mechanical resonators. We fabricated multiple graphene mechanical resonators and detected their resonant properties by an optical interference method. The mechanical vibration of the resonators will enter from the linear to the nonlinear intervals if we enhance the external driving power to a certain value. We found that at a fixed drive power, the nonlinearity of a mechanical resonator can be tuned by applying a dc bias current on the resonator itself. The tuning mechanism could be explained by the nonlinear amplitude-frequency dependence theory. Our results may provide a research platform for the study of mechanical nonlinearity by using atomic-thin layer materials.
Fault diagnosis method for machinery based on multi-source conflict information fusion
Authors: Wei Jianfeng , Zhang Faping , Lu Jiping , Yang Xiangfei , Yan Yan
Published: July 2022

Multi-source information fusion diagnosis is usually more reliable than fault diagnosis with a single source employed. However, fusion results may be absurd when fusing highly conflicting information. To address this problem, the Dempster–Shafer (DS) evidence theory is updated by weighting each piece of evidence according to the corresponding contribution to the decision, and a novel fault diagnosis method based on multi-source conflict information fusion is proposed. First, the basic probability assignment of evidence corresponding to the sensor information is given by introducing the feature parameters of electromyographic signals and using the back-propagation neural network. Then, the importance of each piece of evidence is determined by solving the difference degree and exclusion degree among the evidence, and the evidence is assigned weights according to the degree of importance of each piece of evidence in the fusion decision-making process. Next, the weighted evidence is combined for making decisions and further diagnosis after weighted averaging of the evidence with different weights. Finally, the performance of the proposed method is assessed using receiver operating characteristic (ROC) curves. The experimental results show that the areas under the ROC curves for the proposed method are 0.3229, 0.0729 and 0.9271 higher than those of the traditional DS method, Murphy’s method and Yager’s method, respectively, which proves that the proposed method has better diagnostic performance and reliability.
Spectral-coherence guided variational mode extraction and its application in rolling bearing fault diagnosis
Authors: Sun Zhenduo , Zhang Heng , Pang Bin , Su Dandan , Xu Zhenli , Sun Feng
Published: July 2022

Variational mode extraction (VME), inspired by variational mode decomposition (VMD), is a novel fault diagnosis technique that can efficiently extract narrowband modes from multi-component signals. Compared with VMD, VME is more accurate and faster when extracting the narrowband component. However, the preset center frequency ω
c and balance factor α seriously affect the performance of VME. Therefore, spectral-coherence guided VME (SCVME), capable of determining the hyper-parameters automatically, is proposed for fault diagnosis of rolling bearings. First, by considering the advantages of spectral coherence (SCoh) for characterizing the cyclostationarity of bearing faults, its energy spectrum is constructed. The energy spectrum of SCoh can intuitively reveal the fault information energy hidden in each frequency, which provides sufficient support for the determination of the center frequency ωc. Subsequently, a novel signal evaluation index named cyclic pulse intensity (CPI) is proposed to adaptively optimize the balance factor α. It is verified that the proposed CPI index is superior to common metrics, such as kurtosis, spectral kurtosis and l
2/l
1 norm, used for identifying periodic pulses. Finally, the modes containing fault information are accurately extracted by VME according to the optimal parameters (ωc
, α). The effectiveness of the proposed method is demonstrated by simulations and experiments. In addition, comparisons with the VMD and Autogram methods are carried out to highlight the superiority of the SCVME method.
A novel high-speed bi-directional piezoelectric inchworm actuator based on flexible supported baffles
Authors: Sun Tiantian , Yan Peng
Published: July 2022

Typical bionic piezoelectric inchworm actuators utilize at least two clamping piezo-stacks (PZTs) and one driving PZT to achieve bi-directional actuation, resulting in complex structures, complicated electronic systems, and high cost. Actuators with lesser PZTs (1 or 2) can effectively alleviate these problems; however, existing designs are limited to unidirectional or bidirectional low-speed motion. This study proposes a high-speed bi-directional inchworm actuator with two PZTs, where the clamping switching is achieved by only one PZT through innovative use of flexible supported baffles and enhanced clamping mechanisms. The design also reduces the six sub-steps of the driving principle (alternate elongation and shortening of three PZTs) required for each step of typical designs to four, thus effectively increasing the maximum speed of the actuation. Experimental results show that the proposed design facilitates bi-directional motions in a stable manner with a maximum speed of 5.1 mm s−1, which is approximately 23 times faster than the existing design with two PZTs. The proposed design can effectively expand the application range of dual-piezoelectric inchworm actuators and can find a promising application in the field of high-speed precision positioning.