bluuebunny/crossref_metadata_2025 huggingface dataset:
Migration of Reversing Dunes Against the Sand Flow Path as a Singular Expression of the Speed‐Up Effect
Authors: Gao Xin , Narteau Clément , Gadal Cyril
Published: April 2021

We study the morphodynamics of reversing dunes on the gravel deposits of the alluvial fan of the Molcha river at the border between the Tibetan Plateau and the Taklamakan Desert. Independent sets of wind data show that this area of low sand availability is exposed to two prevailing winds from opposite directions and of different strengths. The predicted resultant transport direction of sand particles is westward. Nevertheless, satellite observations combined with field measurements and ground‐penetrating radar surveys reveal that isolated dunes a few meters high migrate eastward. This apparent dune migration paradox is resolved using numerical and analytical models that take into account the speed‐up effect and the continuous change in dune shape after each wind reversal. When a newly established wind hits what was before the steeper lee slope of the dune, the sand flux at the crest abruptly increases before relaxing back to a constant value as the crest migrates downwind and as the dune reaches a new steady shape. Integrated over the entire wind cycle, we find that this non‐linear behavior causes reversing dunes to migrate against the resultant transport direction. This migration reflects the difference in dune slope seen by irregular storm events blowing to the east and the westward wind of the daily cycle. Thus, we explore the impact of extreme events on dune morphodynamics and examine new aspects of the permanent feedback between dune topography and wind speed. We conclude that transient behaviors associated with crest reversals contribute to the observed diversity of dune patterns, even within the same area for dunes of different sizes.
Saharan Dust Effects on North Atlantic Sea‐Surface Skin Temperatures
Authors: Luo Bingkun , Minnett Peter J. , Zuidema Paquita , Nalli Nicholas R. , Akella Santha
Published: April 2021

Saharan dust outbreaks frequently propagate westward over the Atlantic Ocean; accurate quantification of the dust aerosol scattering and absorption effect on the surface radiative fluxes (SRF) is fundamental to understanding critical climate feedbacks. By exploiting large sets of measurements from many ship campaigns in conjunction with reanalysis products, this study characterizes the sensitivity of the SRF and skin Sea‐Surface Temperature (SSTskin) to the Saharan dust aerosols using models of the atmospheric radiative transfer and thermal skin effect. Saharan dust outbreaks can decrease the surface shortwave radiation up to 190 W/m2, and an analysis of the corresponding SSTskin changes using a thermal skin model suggests dust‐induced cooling effects as large as −0.24 K during daytime and a warming effect of up of 0.06 K during daytime and nighttime respectively. Greater physical insight into the radiative transfer through an aerosol‐burdened atmosphere will substantially improve the predictive capabilities of weather and climate studies on a regional basis.
Hypoxia-inducible factor-2α mediates senescence-associated intrinsic mechanisms of age-related bone loss
Authors: Lee Sun Young , Park Ka Hyon , Lee Gyuseok , Kim Su-Jin , Song Won-Hyun , Kwon Seung-Hee , Koh Jeong-Tae , Huh Yun Hyun , Ryu Je-Hwang
Published: April 2021

Aging is associated with cellular senescence followed by bone loss leading to bone fragility in humans. However, the regulators associated with cellular senescence in aged bones need to be identified. Hypoxia-inducible factor (HIF)−2α regulates bone remodeling via the differentiation of osteoblasts and osteoclasts. Here, we report that HIF-2α expression was highly upregulated in aged bones. HIF-2α depletion in male mice reversed age-induced bone loss, as evidenced by an increase in the number of osteoblasts and a decrease in the number of osteoclasts. In an in vitro model of doxorubicin-mediated senescence, the expression of Hif-2α and p21, a senescence marker gene, was enhanced, and osteoblastic differentiation of primary mouse calvarial preosteoblast cells was inhibited. Inhibition of senescence-induced upregulation of HIF-2α expression during matrix maturation, but not during the proliferation stage of osteoblast differentiation, reversed the age-related decrease in Runx2 and Ocn expression. However, HIF-2α knockdown did not affect p21 expression or senescence progression, indicating that HIF-2α expression upregulation in senescent osteoblasts may be a result of aging rather than a cause of cellular senescence. Osteoclasts are known to induce a senescent phenotype during in vitro osteoclastogenesis. Consistent with increased HIF-2α expression, the expression of p16 and p21 was upregulated during osteoclastogenesis of bone marrow macrophages. ChIP following overexpression or knockdown of HIF-2α using adenovirus revealed that p16 and p21 are direct targets of HIF-2α in osteoclasts. Osteoblast-specific (Hif-2αfl/fl;Col1a1-Cre) or osteoclast-specific (Hif-2αfl/fl;Ctsk-Cre) conditional knockout of HIF-2α in male mice reversed age-related bone loss. Collectively, our results suggest that HIF-2α acts as a senescence-related intrinsic factor in age-related dysfunction of bone homeostasis.
Superior thermal stability and fast crystallization behavior of a novel, biodegradable α-methylated bacterial polyester
Authors: Furutate Sho , Kamoi Junichi , Nomura Christopher T. , Taguchi Seiichi , Abe Hideki , Tsuge Takeharu
Published: April 2021

Given their ubiquity in modern society, the development of biodegradable and renewably sourced plastics is essential for the creation of an environmentally sustainable society. One of the drawbacks for currently available biodegradable plastics such as poly(l-lactic acid) (PLLA) and polyhydroxyalkanoates (PHAs) is that it is difficult to simultaneously achieve mechanical flexibility and certain crystallization behavior in these materials, which limits their use as replacements for established petroleum-based plastics such as isotactic polypropylene (iPP). Here, we report the synthesis and characterization of a new biodegradable plastic, poly(3-hydroxy-2-methylbutyrate) [P(3H2MB)], which is a member of the bacterial PHA family whose members include an α-methylated monomer unit. Biosynthesis of P(3H2MB) was achieved using recombinant Escherichiacoli expressing an engineered pathway. Biosynthesized P(3H2MB) exhibited the highest melting temperature (197 °C) among the biosynthesized PHAs and improved thermal resistance. It also exhibited improved crystallization behavior and mechanical flexibility nearly equal to those of iPP. The primary nucleation rate of P(3H2MB) was faster than that of P(3HB), and the spherulite morphology of P(3H2MB) was much finer than that of P(3HB). This crystal morphology may result in more rapid crystallization behavior, increased transparency, and enhanced mechanical properties. The superior physical properties of P(3H2MB) have the potential to open new avenues for the production of high-performance biodegradable plastics for replacing petroleum-based bulk commodity plastics.
Intracellular gallium nitride microrod laser
Authors: Song Minho S. , Baek Hyeonjun , Lee Keundong , Yoo Dongha , Chung Kunook , Lee Jamin , Moon Hyungseok C. , Lee Byung Hun , Park Hye Yoon , Yi Gyu-Chul
Published: April 2021

We report laser emission from gallium nitride (GaN) microrods that are introduced into mammalian cells and the application of these microrods for cell labeling. GaN microrods were grown on graphene-coated SiO2/Si substrates by metal-organic vapor phase epitaxy. The GaN microrods are easily detached from the substrates because of the weakness of the van der Waals forces between GaN and graphene. The uptake of microrods into HeLa cells via endocytosis and viability after uptake were investigated. Normal cellular activities, including migration and division, were observed over 2 weeks in culture. Furthermore, the photoluminescence spectra of the internalized microrods exhibited sharp laser emission peaks with a low lasing threshold of 270 kW/cm2.
Genetic variability in COVID-19-related genes in the Brazilian population
Authors: Secolin Rodrigo , de Araujo Tânia K. , Gonsales Marina C. , Rocha Cristiane S. , Naslavsky Michel , Marco Luiz De , Bicalho Maria A. C. , Vazquez Vinicius L. , Zatz Mayana , Silva Wilson A. , Lopes-Cendes Iscia
Published: April 2021

SARS-CoV-2 utilizes the angiotensin-converting enzyme 2 (ACE2) receptor and transmembrane serine protease (TMPRSS2) to infect human lung cells. Previous studies have suggested that different host ACE2 and TMPRSS2 genetic backgrounds might contribute to differences in the rate of SARS-CoV-2 infection or COVID-19 severity. Recent studies have also shown that variants in 15 genes related to type I interferon immunity to influenza virus might predispose patients toward life-threatening COVID-19 pneumonia. Other genes (SLC6A20, LZTFL1, CCR9, FYCO1, CXCR6, XCR1, IL6, CTSL, ABO, and FURIN) and HLA alleles have also been implicated in the response to infection with SARS-CoV-2. Currently, Brazil has recorded the third-highest number of COVID-19 cases worldwide. We aimed to investigate the genetic variation present in COVID-19-related genes in the Brazilian population. We analyzed 27 candidate genes and HLA alleles in 954 admixed Brazilian exomes. We used the information available in two public databases (http://www.bipmed.org and http://abraom.ib.usp.br/) and additional exomes from individuals born in southeast Brazil, the region of the country with the highest number of COVID-19 patients. Variant allele frequencies were compared with the 1000 Genomes Project phase 3 (1KGP) and gnomAD databases. We detected 395 nonsynonymous variants; of these, 325 were also found in the 1KGP and/or gnomAD. Six of these variants were previously reported to influence the rate of infection or clinical prognosis of COVID-19. The remaining 70 variants were identified exclusively in the Brazilian sample, with a mean allele frequency of 0.0025. In silico analysis revealed that seven of these variants are predicted to affect protein function. Furthermore, we identified HLA alleles previously associated with the COVID-19 response at loci DQB1 and DRB1. Our results showed genetic variability common to other populations and rare and ultrarare variants exclusively found in the Brazilian population. These findings might lead to differences in the rate of infection or response to infection by SARS-CoV-2 and should be further investigated in patients with this disease.
A meta-analysis on individual differences in primary emotional systems and Big Five personality traits
Authors: Marengo Davide , Davis Kenneth L. , Gradwohl Gökçe Özkarar , Montag Christian
Published: April 2021

The Affective Neuroscience Personality Scales (ANPS) were constructed as a self-report assessment to measure individual differences in Jaak Panksepp’s cross-species primary emotional systems: SEEKING, PLAY, CARE (positive emotions) and FEAR, SADNESS, ANGER (negative emotions). Beginning with the first published work on the ANPS in 2003, individual differences on the ANPS measures of these six primary emotional systems have been consistently linked to Big Five personality traits. From a theoretical perspective, these primary emotional systems arising from subcortical regions, shed light on the nature of the Big Five personality traits from an evolutionary perspective, because each of these primary emotional systems represent a tool for survival endowing mammalian species with inherited behavioral programs to react appropriately to complex environments. The present work revisited 21 available samples where both ANPS and Big Five measures have been administered. Our meta-analytical analysis provides solid evidence that high SEEKING relates to high Openness to Experience, high PLAY to high Extraversion, high CARE/low ANGER to high Agreeableness and high FEAR/SADNESS/ANGER to high Neuroticism. This seems to be true regardless of the ANPS inventory chosen, although much more work is needed in this area. Associations between primary emotional systems and Conscientiousness were in the lower effect size area across all six primary emotions, thereby supporting the idea that Conscientiousness rather seems to be less directly related with the subcortical primary emotions and likely is the most cognitive/cortical personality construct out of the Big Five. In sum, the present work underlines the idea that individual differences in primary emotional systems represent evolutionarily ancient foundations of human personality, given their a) meaningful links to the prominent Big Five model and b) their origins lying in subcortical areas of the human brain.
Culturable nitrogen-transforming bacteria from sequential sedimentation biofiltration systems and their potential for nutrient removal in urban polluted rivers
Authors: Font Nájera Arnoldo , Serwecińska Liliana , Mankiewicz-Boczek Joanna
Published: April 2021

Novel heterotrophic bacterial strains—Bzr02 and Str21, effective in nitrogen transformation, were isolated from sequential sedimentation-biofiltration systems (SSBSs). Bzr02, identified as Citrobacter freundii, removed up to 99.0% of N–NH4 and 70.2% of N–NO3, while Str21, identified as Pseudomonas mandelii, removed up to 98.9% of N–NH4 and 87.7% of N–NO3. The key functional genes napA/narG and hao were detected for Bzr02, confirming its ability to reduce nitrate to nitrite and remove hydroxylamine. Str21 was detected with the genes narG, nirS, norB and nosZ, confirming its potential for complete denitrification process. Nitrogen total balance experiments determined that Bzr02 and Str21 incorporated nitrogen into cell biomass (up to 94.7% and 74.7%, respectively), suggesting that nitrogen assimilation was also an important process occurring simultaneously with denitrification. Based on these results, both strains are suitable candidates for improving nutrient removal efficiencies in nature-based solutions such as SSBSs.
Analysis of the chromosomal clustering of Fusarium-responsive wheat genes uncovers new players in the defence against head blight disease
Authors: Perochon Alexandre , Benbow Harriet R. , Ślęczka-Brady Katarzyna , Malla Keshav B. , Doohan Fiona M.
Published: April 2021

There is increasing evidence that some functionally related, co-expressed genes cluster within eukaryotic genomes. We present a novel pipeline that delineates such eukaryotic gene clusters. Using this tool for bread wheat, we uncovered 44 clusters of genes that are responsive to the fungal pathogen Fusarium graminearum. As expected, these Fusarium-responsive gene clusters (FRGCs) included metabolic gene clusters, many of which are associated with disease resistance, but hitherto not described for wheat. However, the majority of the FRGCs are non-metabolic, many of which contain clusters of paralogues, including those implicated in plant disease responses, such as glutathione transferases, MAP kinases, and germin-like proteins. 20 of the FRGCs encode nonhomologous, non-metabolic genes (including defence-related genes). One of these clusters includes the characterised Fusarium resistance orphan gene, TaFROG. Eight of the FRGCs map within 6 FHB resistance loci. One small QTL on chromosome 7D (4.7 Mb) encodes eight Fusarium-responsive genes, five of which are within a FRGC. This study provides a new tool to identify genomic regions enriched in genes responsive to specific traits of interest and applied herein it highlighted gene families, genetic loci and biological pathways of importance in the response of wheat to disease.
Activity patterns of primary school children during participation in The Daily Mile
Authors: Hatch Lorna M. , Williams Ryan A. , Dring Karah J. , Sunderland Caroline , Nevill Mary E. , Cooper Simon B.
Published: April 2021

The Daily Mile is a popular physical activity initiative in primary schools, yet little is known regarding the activity patterns of children during The Daily Mile. Eighty children (10.4 ± 0.7 years) participated in The Daily Mile (20-min). Activity patterns were assessed using global positioning systems (total distance and age-specific speed zones), alongside heart rate. Cardiorespiratory fitness was assessed using the Multi-Stage Fitness Test. Participants covered a distance of 2511 ± 550 m during The Daily Mile, and heart rate was 163 ± 27 beats.min−1. Participants travelled the furthest distance, and were most intermittent, during the first 5 min (main effect of time, both p < 0.001). Boys ran further and their activity was more intermittent compared to girls (main effect of sex, both p < 0.001). Moreover, the highest fit children ran further than less fit children (main effect of fitness, p < 0.001). This study provides novel evidence of the nature of physical activity during The Daily Mile; demonstrating that children covered, on average, 1.5-miles and exercised at a moderate-to-vigorous intensity. Furthermore, boys covered a greater distance and were more intermittent than girls; whilst higher fit children ran further than lower fit children. In summary, The Daily Mile makes a valuable contribution to in-school physical activity targets in all children.
Large-scale screening of natural genetic resource in the hydrocarbon-producing microalga Botrycoccus braunii identified novel fast-growing strains
Authors: Kawamura Koji , Nishikawa Suzune , Hirano Kotaro , Ardianor Ardianor , Nugroho Rudy Agung , Okada Shigeru
Published: April 2021

Algal biofuel research aims to make a renewable, carbon–neutral biofuel by using oil-producing microalgae. The freshwater microalga Botryococcus braunii has received much attention due to its ability to accumulate large amounts of petroleum-like hydrocarbons but suffers from slow growth. We performed a large-scale screening of fast-growing strains with 180 strains isolated from 22 ponds located in a wide geographic range from the tropics to cool-temperate. A fast-growing strain, Showa, which recorded the highest productivities of algal hydrocarbons to date, was used as a benchmark. The initial screening was performed by monitoring optical densities in glass tubes and identified 9 wild strains with faster or equivalent growth rates to Showa. The biomass-based assessments showed that biomass and hydrocarbon productivities of these strains were 12–37% and 11–88% higher than that of Showa, respectively. One strain, OIT-678 established a new record of the fastest growth rate in the race B strains with a doubling time of 1.2 days. The OIT-678 had 36% higher biomass productivity, 34% higher hydrocarbon productivity, and 20% higher biomass density than Showa at the same cultivation conditions, suggesting the potential of the new strain to break the record for the highest productivities of hydrocarbons.
Detection of loci exhibiting pleiotropic effects on body weight and egg number in female broilers
Authors: Tarsani Eirini , Kranis Andreas , Maniatis Gerasimos , Hager-Theodorides Ariadne L. , Kominakis Antonios
Published: April 2021

The objective of the present study was to discover the genetic variants, functional candidate genes, biological processes and molecular functions underlying the negative genetic correlation observed between body weight (BW) and egg number (EN) traits in female broilers. To this end, first a bivariate genome-wide association and second stepwise conditional-joint analyses were performed using 2586 female broilers and 240 k autosomal SNPs. The aforementioned analyses resulted in a total number of 49 independent cross-phenotype (CP) significant SNPs with 35 independent markers showing antagonistic action i.e., positive effects on one trait and negative effects on the other trait. A number of 33 independent CP SNPs were located within 26 and 14 protein coding and long non-coding RNA genes, respectively. Furthermore, 26 independent markers were situated within 44 reported QTLs, most of them related to growth traits. Investigation of the functional role of protein coding genes via pathway and gene ontology analyses highlighted four candidates (CPEB3, ACVR1, MAST2andCACNA1H) as most plausible pleiotropic genes for the traits under study. Three candidates (CPEB3, MAST2andCACNA1H) were associated with antagonistic pleiotropy, whileACVR1with synergistic pleiotropic action. Current results provide a novel insight into the biological mechanism of the genetic trade-off between growth and reproduction, in broilers.
Bayesian analysis of cytokines and chemokine identifies immune pathways of HBsAg loss during chronic hepatitis B treatment
Authors: Narayanan Sriram , Au Veonice Bijin , Khakpoor Atefeh , Yan Cheng , Ahl Patricia J. , Kaliaperumal Nivashini , Lee Bernett , Xiang Wen Wei , Wang Juling , Lee Chris , Tay Amy , Lim Seng Gee , Connolly John E.
Published: April 2021

Our objective was to examine differences in cytokine/chemokine response in chronic hepatitis B(CHB) patients to understand the immune mechanism of HBsAg loss (functional cure) during antiviral therapy. We used an unbiased machine learning strategy to unravel the immune pathways in CHB nucleo(t)side analogue-treated patients who achieved HBsAg loss with peg-interferon-α(peg-IFN-α) add-on or switch treatment in a randomised clinical trial. Cytokines/chemokines from plasma were compared between those with/without HBsAg loss, at baseline, before and after HBsAg loss. Peg-IFN-α treatment resulted in higher levels of IL-27, IL-12p70, IL-18, IL-13, IL-4, IL-22 and GM-CSF prior to HBsAg loss. Probabilistic network analysis of cytokines, chemokines and soluble factors suggested a dynamic dendritic cell driven NK and T cell immune response associated with HBsAg loss. Bayesian network analysis showed a dominant myeloid-driven type 1 inflammatory response with a MIG and I-TAC central module contributing to HBsAg loss in the add-on arm. In the switch arm, HBsAg loss was associated with a T cell activation module exemplified by high levels of CD40L suggesting T cell activation. Our findings show that more than one immune pathway to HBsAg loss was found with peg-IFN-α therapy; by myeloid-driven Type 1 response in one instance, and T cell activation in the other.
Mixed convection stagnation point flow of the blood based hybrid nanofluid around a rotating sphere
Authors: Gul Taza , Ali Basit , Alghamdi Wajdi , Nasir Saleem , Saeed Anwar , Kumam Poom , Mukhtar Safyan , Kumam Wiyada , Jawad Muhammad
Published: April 2021

In this new world of fluid technologies, hybrid nanofluid has become a productive subject of research among scientists for its potential thermal features and abilities, which provides an excellent result as compared to nanofluids in growing the rate of heat transport. Our purpose here is to introduce the substantial influences of magnetic field on 2D, time-dependent and stagnation point inviscid flow of couple stress hybrid nanofluid around a rotating sphere with base fluid is pure blood, $${\text{TiO}}_{2} \,\,{\text{and}}\,\,{\text{Ag}}$$

TiO
2

and

Ag

as the nanoparticles. To translate the governing system of partial differential equations and the boundary conditions relevant for computation, some suitable transformations are implemented. To obtain the analytical estimations for the corresponding system of differential expression, the innovative Optimal Homotopy Analysis Method is used. The characteristics of hybrid nanofluid flow patterns, including temperature, velocity and concentration profiles are simulated and analyzed in detail due to the variation in the evolving variables. Detailed research is also performed to investigate the influences of relevant constraints on the rates, momentum and heat transport for both $${\text{TiO}}_{2} + {\text{Ag}} + Blood$$

TiO
2

+
Ag
+
B
l
o
o
d

and $${\text{TiO}}_{2} + Blood$$

TiO
2

+
B
l
o
o
d

. One of the many outcomes of this analysis, it is observed that increasing the magnetic factor will decelerate the hybrid nanofluid flow velocity and improve the temperature profile. It may also be demonstrated that by increasing the Brownian motion factor, significant improvement can be made in the concentration field of hybrid nanofluid. The increase in the nanoparticle volume fraction from 0.01 to 0.02 in the case of the hybrid nanofluid enhances the thermal conductivity from 5.8 to 11.947% and for the same value of the nanoparticle volume fraction in the case of nanofluid enhance the thermal conductivity from 2.576 to 5.197%.
Synergistic zinc doping and defect engineering toward MoS2 nanosheet arrays for highly efficient electrocatalytic hydrogen evolution
Authors: Wang Yi-long , Huang Qing , Sun Guo-qi , Li Xiao-yun , Chen Li-hua , Su Bao-lian , Liu Jin-ping
Published: April 2021

Synergistic zinc doping and defect engineering toward freestanding MoS2 nanosheet arrays are realized via a one-step synthesis, enabling high efficiency for the HER.
Effects of disinfectants and particles on the occurrence of different microorganisms in drinking water distribution systems
Authors: Huo Lixin , Pan Linlin , Chen Ruya , Shi Baoyou , Wang Haibo , He Shouyang
Published: April 2021

The effects of disinfectants and particles on different bacteria, including total coliforms, heterotrophic plate count, opportunistic pathogens and amoeba hosts, were investigated in drinking water distribution systems from five treatment plants.
C–H hetero-functionalization of arenes through palladacyclopentane-type intermediates
Authors: Cao Liming , Hua Yu , Cheng Hong-Gang , Zhou Qianghui
Published: April 2021

In this review article, we summarized recent advances in C–H hetero-functionalization of arenes through palladacyclopentane-type intermediates.
Flexo-photoelectronic effect in n-type/p-type two-dimensional semiconductors and a deriving light-stimulated artificial synapse
Authors: Wang Xiang , Zhou Xin , Cui Anyang , Deng Menghan , Xu Xionghu , Xu Liping , Ye Yan , Jiang Kai , Shang Liyan , Zhu Liangqing , Zhang Jinzhong , Li Yawei , Hu Zhigao , Chu Junhao
Published: April 2021

We demonstrate flexo-photoelectronic effects of both n-type and p-type 2D semiconductors.
Target-switchable DNA hydrogels coupled with a Bi2Sn2O7/Bi2S3 heterojunction based on in situ anion exchange for the “signal-on” photoelectrochemical detection of DNA
Authors: Li Hongkun , Cai Qianqian , Yan Xiaoshi , Jie Guifen
Published: April 2021

In this paper, a novel photoelectrochemical (PEC) “signal-on” biosensor based on a Bi2Sn2O7/Bi2S3 heterojunction coupled with target-switchable DNA hydrogels is reported for the ultrasensitive detection of P53 gene DNA.
A ferroelastic molecular rotor crystal showing inverse temperature symmetry breaking
Authors: Miao Le-Ping , Chu Lin-Lin , Han Xiang-Bin , Liang Bei-Dou , Chai Chao-Yang , Fan Chang-Chun , Wang Xiao-Xu , Yao Ye-Feng , Zhang Wen
Published: April 2021

A molecular rotor crystal shows a ferroelastic phase transition with unique inverse temperature symmetry breaking which is a result of concerted molecular movement triggered by anisotropic steric repulsion among adjacent molecules.
New-phase retention in colloidal core/shell nanocrystals via pressure-modulated phase engineering
Authors: Wang Yixuan , Liu Hao , Wu Min , Wang Kai , Sui Yongming , Liu Zhaodong , Lu Siyu , Nie Zhihong , Tse John S. , Yang Xinyi , Zou Bo
Published: April 2021

Core/shell MnSe/MnS nanocrystals with the B31 phase are thermodynamically stable under high pressure and can survive under ambient conditions owing to the synergistic effect of subtle enthalpy differences and high surface energy in nanomaterials.
Stabilizing a three-center single-electron metal–metal bond in a fullerene cage
Authors: Jin Fei , Xin Jinpeng , Guan Runnan , Xie Xiao-Ming , Chen Muqing , Zhang Qianyan , Popov Alexey A. , Xie Su-Yuan , Yang Shangfeng
Published: April 2021

A novel trimetallic carbide clusterfullerene, Dy3C2@Ih(7)-C80, was successfully synthesized and isolated, and the encapsulated Dy3C2cluster adopts a bat ray configuration featuring an unprecedented three-center single-electron Dy–Dy–Dy bond.
Different hybrid machine intelligence techniques for handling IoT‐based imbalanced data
Authors: Mohindru Gaurav , Mondal Koushik , Banka Haider
Published: April 2021

In the era of automatic task processing or designing complex algorithms, to analyse data, it is always pertinent to find real‐life solutions using cutting‐edge tools and techniques to generate insights into the data. The data‐driven machine learning models are now offering more or less worthy results when they are certainly balanced in the input data sets. Imbalanced data occurs when an unequal distribution of classes occurs in the input datasets. Building a predictive model on the imbalanced data set would cause a model that appears to yield high accuracy but does not generalize well to the new data in the minority class. Now the time has come to look into the datasets which are not so‐called ‘balanced’ in nature but such datasets are generally encountered frequently in a workspace. To prevent creating models with false levels of accuracy, the imbalanced data should be rearranged before creating a predictive model. Those data are, sometimes, voluminous, heterogeneous and complex in nature and generate from different autonomous sources with distributed and decentralized control. The driving force is to efficiently handle these data sets using latest tools and techniques for research and commercial insights. The present article provides different such tools and techniques, in different computing frameworks, to handle such Internet of Things and other related datasets to review common techniques for handling imbalanced data in data ecosystems and offers a comparative data modelling framework in Keras for balanced and imbalanced datasets.
Design of FSS‐antenna‐radome system for airborne and ground applications
Authors: Tahseen Hafiz Usman , Yang Lixia , Zhou Xiang
Published: April 2021

Radome being an RF window and support structure for an antenna system is a very critical element of terrestrial and airborne radar systems. This paper presents an efficient X‐band frequency select surface (FSS)‐antenna‐radome system for airborne and ground applications. In the first step, an optimum wall configuration with lowest insertion loss is found out of A‐sandwich, C‐sandwich and multilayers wall configurations. In the second step, two 5×5 arrays (FSS screens) are designed that cover the whole antenna face in the broadside direction for a controlled and secure communication system. A slotted array on a dielectric substrate gives a bandpass feature with antenna for radome operation. A dipole array on a dielectric substrate gives a broader bandwidth with antenna somewhat different from antenna alone. It makes the antenna to stop radiating for a specific band. So, it gives bandstop feature. This proposed FSS‐antenna‐radome system is demonstrated with an X‐band high directional horn antenna over the frequency range 9.4–16 GHz under a sandwich‐wall dielectric radome. The bandpass and bandstop features make this proposed FSS‐antenna‐radome a good candidate for ground and airborne applications for secure communications. In bandpass feature, antenna becomes inaccessible to other antennas/radars except a narrow band.
Transformer inter‐turn failure detection based on leakage flux and vibration analysis
Authors: Hajiaghasi Salman , Hosseini Ahmadi Mohammad Milad , Goleij Pedram , Salemnia Ahmad
Published: April 2021

Inter‐turn winding fault is one of the most critical failures of the transformers. Here, a comprehensive transformer leakage flux analysis under inter‐turn winding fault is presented, and the feasibility and sensitivity of leakage flux‐based fault detection methods are investigated. The leakage flux fault detection strategies are classified into vibration‐based methods and search coil‐based methods. Flux leakage‐based methods have been studied and compared. Moreover, the effects of various important factors, such as fault severity, fault location, load power factor, and loading rate in transformer under inter‐turn faults are studied. Furthermore, two new online methods based on leakage flux and vibration analysis are proposed. In the first method, search coils voltage analysis is used for fault detection. In the second one, the vibration of the transformer is measured using the Digital Accelerometer (ADXL) sensor and compared with the vibration of the normal conditions, and based on the amount of vibration, fault detection is performed. The simulation and experimentation results on 20/0.4 kV, 50 kVA distribution transformer demonstrated that the implementation of leakage flux‐based methods provides valuable information on the transformer behaviour, which can be used to detect transformer winding faults.
MP2020: Visual quality assessment database for macro photography images
Authors: Sang Qingbing , Cao Yujie , Liu Lixiong , Hu Cong , Wu Xiaojun
Published: April 2021

With the development of mobile phone camera technology, mobile phones can take a large number of macro photography images that previously could only be taken by professional cameras. Therefore, it is of great significance to study the quality of macro photography images. For this reason, a macro photography image visual quality evaluation database is established and it is named as MP2020. The database contains 100 reference images and 800 distorted images of four distortion types, including 200 distorted images of JPEG 2000, 200 distorted images of JPEG, 200 distorted images of white noise, and 200 distorted images of Gaussian blur. The DMOS values in the database were calculated from 48000 data which are provided by 60 subjects. Ten classical image quality assessment algorithms were tested on the MP2020 database. The experimental results show that the existing image quality assessment algorithms, which are widely used, are not applicable to the macro photography images. Therefore, MP2020 would contribute to the improvement of existing algorithms and the development of new algorithms. MP2020 has been uploaded to GitHub for download.
A photo‐based quality assessment model for the estimation of PM2.5 concentrations
Authors: Sun Kezheng , Tang Lijuan , Huang Shuaifeng , Qian Jiansheng
Published: April 2021

Rapid economic growth has caused severe environmental pollution, which has aroused great concern. This pollution affects public health and impairs visibility, therefore, it should be given greater consideration. In this paper, a photo‐based PM2.5 concentration predictor is proposed based on the natural scene statistics without artificial assistance or extra information. Given that the quality of PM2.5 concentration images is determined by many factors, three types of influencing factors are analysed: the colourfulness, the structural degradation and the contrast. The first feature consists of the hue, saturation and colour descriptors, which measure the colourfulness of the PM2.5 concentration images. The second feature is determined based on the contrast can effectively portray the quality of PM2.5 concentration in the images. The third feature is extracted based on the natural scene statistics model, which measures the local and global structural degradation information and the naturalness of the PM2.5 concentration images. Finally, the three features are used to train a random forest model that can be used to predict the concentration of PM2.5. Experimental results illustrate that the performance of the proposed model is better than those of popular competitors on AQID.
Ecological cooperative adaptive cruise control of over‐actuated electric vehicles with in‐wheel motor in traffic flow
Authors: Xia Dong , Li Boyuan , Zhang Jie , Zhang Bangji , Zhang Nong
Published: April 2021

Since electric vehicle with in‐wheel motor has advantages in aspects of vehicle dynamics control and energy‐efficient control, it has been widely applied in the vehicle platoon in the highway. This paper proposes an optimization and control structure that integrates ecological cooperative adaptive cruise control (CACC) for the vehicle platoon, and path tracking and ecological control allocation (Eco‐CA) for individual vehicle to improve the energy efficiency of electric vehicles in traffic flow. First, in the upper layer, the suitable driving mode is selected by finite‐state machine (FSM) based on surrounding environment. Then the path‐planner and ecological CACC in the higher layer are proposed to determine the desired path and desired speed and acceleration profile. After that, in the middle layer, longitudinal motion controller and yaw stability controller are integrated to achieve the desired control targets from upper layer. Finally, in the lower layer, each in‐wheel motor torque is optimized by Eco‐CA subsystem to reduce the energy consumption of driving motor and tyre friction loss. The simulation results demonstrate that the proposed control strategy can improve the energy efficiency and dynamics control performance.
Real‐time coordination of connected vehicles at intersections using graphical mixed integer optimization
Authors: Ge Qiang , Sun Qi , Wang Zhen , Li Shengbo Eben , Gu Ziqing , Zheng Sifa , Liao Lyuchao
Published: April 2021

Management of connected vehicles at unsignalised intersections is a large‐scale complex problem with safety constraints and time‐varying unsolved variables, which is crucial but hard to solve online. A faster coordination system, however, not only benefits from smaller time granularity to find optimum, but also has more robustness towards a scenario with fast‐moving vehicle nodes. This paper proposes a real‐time coordination scheme consisting of three stages. (a) Target velocity optimisation: collision‐free passage is formulated as a mixed integer linear programming problem, each approaching lane corresponding to an independent variable; (b) vehicle subgraph extraction: a directed graph is built and pruned based on the optimisation result, determining a subgraph wherein vehicle nodes pass without redundant time slot; (c) velocity profile synchronisation: velocity profile of the selected vehicles is planned synchronously, respecting inter‐subgraph constraints. The main contribution of this study is to propose a fast hierarchical optimization‐based coordination method, of which the complexity is invariant with the traffic density. Simulation has verified the effectiveness of the scheme from both microscopic behaviour and statistical characteristics, reducing single‐step computation time to 0.02 s, and saving average driving delay by 59.83% compared to the benchmark method.
Excitation of guided waves of grounded dielectric slab by a THz plane wave scattered from finite number of embedded graphene strips: Singular integral equation analysis
Authors: Kaliberda Mstislav E. , Lytvynenko Leonid M. , Pogarsky Sergey A. , Sauleau Ronan
Published: April 2021

The scattering and absorption of the H‐polarised wave by a finite number of graphene strips embedded into a grounded dielectric slab is considered in the terahertz frequency range. The rigorous and efficient method of singular integral equations is used here. The discretisation is based on the convergent meshless Nystrom‐type algorithm. Graphene is modelled as a zero thickness layer with a complex conductivity obtained from the Kubo formalism. Dependences of the total scattering cross section, including the part that is associated with dielectric slab guided waves, and absorption cross section as well as near field patterns are studied. The behaviour of the scattering and absorption characteristics is explained in terms of resonances on the natural modes supported by the studied structure. Special attention is paid to the excitation of the dielectric waveguide eigenwaves near the grating‐mode resonances.
Pure dipole radiation via exact solution of Maxwell's equations with spherical source electric current density
Authors: Garren David Alan
Published: April 2021

Magnetic loop antennas are valuable for low frequency radar and communications applications, especially for frequencies below 1 MHz. The present paper examines a possible new type of magnetic antenna which is based on a spherical distribution of source electric current. Specifically, this analysis examines a spherically shaped azimuthal electric current density with a magnitude that is proportional to the sine of the spherical elevation angle. A theoretic analytic investigation of the resultant electromagnetic (EM) fields yields an exact closed‐form solution of Maxwell's equations which is expressed in terms of a small number of elemental functions. This emanated radiation has a purely dipole structure, with the absence of any higher order multipole contributions. This pure dipole property might offer new applications in radar and communications, provided that suitable physical antenna systems can be fabricated based on the subject theoretical concepts.
[CII] emission properties of the massive star-forming region RCW 36 in a filamentary molecular cloud
Authors: Suzuki T. , Oyabu S. , Ghosh S. K. , Ojha D. K. , Kaneda H. , Maeda H. , Nakagawa T. , Ninan J. P. , Vig S. , Hanaoka M. , Saito F. , Fujiwara S. , Kanayama T.
Published: April 2021

Aims. We investigate the properties of [C II] 158 μm emission of RCW 36 in a dense filamentary cloud.

Methods. [C II] observations of RCW 36, covering an area of ~30′ × 30′, were carried out with a Fabry-Pérot spectrometer on board a 100-cm balloon-borne far-infrared (IR) telescope with an angular resolution of 90′′. Using AKARI and Herschel images, we compared the spatial distribution of the [C II] intensity with the emission from the large grains and polycyclic aromatic hydrocarbon (PAH).

Results. The [C II] emission is in good spatial agreement with shell-like structures of a bipolar lobe observed in IR images, which extend along the direction perpendicular to the direction of cold dense filament. We found that the [C II]–160 μm relation for RCW 36 shows a higher brightness ratio of [C II]/160 μm than that for RCW 38, while the [C II]–9 μm relation for RCW 36 is in good agreement with that for RCW 38.

Conclusions. Via a spectral decomposition analysis on a pixel-by-pixel basis using IR images, the [C II] emission is spatially well correlated with PAH and cold dust emissions. This means that the observed [C II] emission predominantly comes from photo-dissociation regions. Moreover, the L[C II]∕LFIR ratio shows large variation (10−2–10−3), as compared with the L[C II]/LPAH ratio. In view of the observed tight correlation between L[C II]∕LFIR and the optical depth at λ = 160 μm, the large variation in L[C II]∕LFIR can be simply explained by the geometrical effect, that is, LFIR has contributions from the entire dust-cloud column along the line of sight, while L[C II] has contributions from far-UV illuminated cloud surfaces. Based on the picture of the geometry effect, the enhanced brightness ratio of [C II]/160 μm is attributed to the difference in gas structures where massive stars are formed: filamentary (RCW 36) and clumpy (RCW 38) molecular clouds; thus suggesting that RCW 36 is dominated by far-UV illuminated cloud surfaces, as compared with RCW 38.
Simulations of starspot anomalies within TESS exoplanetary transit light curves
Authors: Tregloan-Reed J. , Unda-Sanzana E.
Published: April 2021

Aims. We determine the starspot detection rate in exoplanetary transit light curves for M and K dwarf stars observed by the Transiting Exoplanet Survey Satellite (TESS) using various starspot filling factors and starspot distributions.

Methods. We used 3.6 × 109 simulations of planetary transits around spotted stars using the transit-starspot model PRISM. The simulations cover a range of starspot filling factors using one of three distributions: uniform, polar-biased, and mid-latitude. After construction of the stellar disc and starspots, we checked the transit cord for starspots and examined the change in flux of each starspot to determine whether or not a starspot anomaly would be detected. The results were then compared to predicted planetary detections for TESS.

Results. The results show that for the case of a uniform starspot distribution, 64 ± 9 M dwarf and 23 ± 4 K dwarf transit light curves observed by TESS will contain a starspot anomaly. This reduces to 37 ± 6 M dwarf and 12 ± 2 K dwarf light curves for a polar-biased distribution and 47 ± 7 M dwarf and 21 ± 4 K dwarf light curves for a mid-latitude distribution.

Conclusions. Currently there are only 17 M dwarf and 10 K dwarf confirmed planetary systems from TESS, none of which are confirmed as showing starspot anomalies. All three starspot distributions can explain the current trend. However, with such a small sample, a firm conclusion cannot be made at present. In the coming years when more TESS M and K dwarf exoplanetary systems have been detected and characterised, it will be possible to determine the dominant starspot distribution.
The final orbital separation in common envelope evolution
Authors: Politano M.
Published: April 2021

In the majority of population synthesis calculations of close binary stars, the common envelope (CE) phase is modeled using a standard prescription based upon the conservation of energy, known as the alpha prescription. In this prescription, the orbital separation of the secondary and giant core at the end of the CE phase is taken to be the orbital separation when the envelope becomes unbound. However, recent observations of planetary nebulae with binary cores (BPNe), believed to be the immediate products of CE evolution, indicate orbital periods that are significantly shorter than predicted by population synthesis models using the alpha prescription. We argue that unbinding the envelope provides a necessary, but not sufficient, condition to escape a merger during CE evolution. The spiral-in of the secondary must also be halted. This requires the additional dynamical constraint that the frictional torque on the secondary be reduced to approximately zero. In this paper, we undertake a preliminary examination of the effect of adding this dynamical constraint in population synthesis calculations of BPNe. We assume that the frictional torque will be sufficiently reduced when the secondary enters a region within the giant where the mass-radius profile is flat. We crudely estimate the location of this region as a function of the core mass based upon existing stellar models of AGB stars between 1 and 7 M⊙. We calculate a theoretical orbital period distribution of BPNe using a population synthesis code that incorporates this dynamical constraint along with the alpha prescription.
Edaphoclimatic factors determining sunflower yields spatiotemporal dynamics in northern Ukraine
Authors: Zymaroieva Anastasiia , Zhukov Oleksandr , Fedoniuk Tetiana , Pinkina Tetyana , Vlasiuk Volodymyr
Published: April 2021

The climate and soil conditions have a significant impact on sunflower yields. Sunflower yield dynamics in the Central European mixed forests (Polissya) and Eastern European forest-steppe ecoregions in Ukraine from 1991 to 2017 was proved to fit a log-logistic model most adequately. The model has four characteristic parameters: the Lower Limit indicates the lowest level of yield over the study period; the Slope indicates the rate of yield increase over time; the ED50 is the time required to reach half of the maximum yield level and simultaneously the point with the highest rate of yield increase; the Upper Limit shows the highest yield level. The parameters of the yield model are used to meaningfully interpret the causes of yield dynamics. Edaphoclimatic factors account for 34 to 58% of the variation in the yield trend parameters. The soil texture and soil organic carbon (SOC) predominate among the edaphic factors that determine the variability of sunflower yield. Continentality of climate and degree of temperature variability during the growing season are the main climatic determinants of sunflower yield parameters.