bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence, infection intensity and geographical distribution of schistosomiasis among pre-school and school aged children in villages surrounding Lake Nyasa, Tanzania
Authors: Mazigo Humphrey Deogratias , Uisso Cecilia , Kazyoba Paul , Nshala Andreas , Mwingira Upendo J.
Published: January 2021

Planning and implementation of schistosomiasis control activities requires an understanding of the prevalence, intensity of infection and geographical distribution of the disease in different epidemiological settings. Although, Tanzania is known to be highly endemic to schistosomiasis, there is paucity of data on the geographical distribution of schistosomiasis in potential large water bodies in the country. Thus, the present study was conducted to determine the prevalence, infection intensities and geographical distribution of schistosomiasis along villages located on the shoreline of Lake Nyasa, southern Tanzania. A cross-sectional study was conducted among 1560 children aged 1–13 years old living in villages located along the shoreline of Lake Nyasa. A single urine and stool sample was obtained from each participating child and screened for S.mansoni using Kato Katz (KK) technique to detect eggs and using point-of-care circulating Cathodic Antigen (POC-CCA) test to detect antigen in urine. Urine filtration technique was used to screen for S.haematobium eggs in urine samples. Villages/primary school were mapped using geographical information system and prevalence map was generated using ArcView GIS software. The overall prevalence of S.mansoni based on KK technique and POC-CCA test was 15.1% (95%CI: 13.4–16.9) and 21.8% (95%CI: 18.5–25.3) respectively. The prevalence S.haematobium was 0.83% (95%CI: 0.5–1.4) and that of haematuria was 0.9%. The arithmetic mean egg intensities for S.haematobium and S.mansoni were 18.5 mean eggs/10 ml (95%CI: 5.9–57.6) of urine and 34.7 mean epg (95%CI: 27.7–41.7) respectively. Villages located on the southern end of the lake had significantly high prevalence of S.mansoni than those located on the northern part (χ2 = 178.7838, P = 0.001). Cases of S.haematobium were detected only in three villages. Both S.mansoni and S.haematobium infections occur in villages located along the shoreline of Lake Nyasa at varying prevalence. These finding provide insights that can provide guidance in planning and implementation of MDA approach and other recommended measures such as improvement in sanitation, provision of clean water and behaviour changes through public health education.
Mitochondrial gene expression in single cells shape pancreatic beta cells' sub-populations and explain variation in insulin pathway
Authors: Medini H. , Cohen T. , Mishmar D.
Published: January 2021

Mitochondrial gene expression is pivotal to cell metabolism. Nevertheless, it is unknown whether it diverges within a given cell type. Here, we analysed single-cell RNA-seq experiments from human pancreatic alpha (N = 3471) and beta cells (N = 1989), as well as mouse beta cells (N = 1094). Cluster analysis revealed two distinct human beta cells populations, which diverged by mitochondrial (mtDNA) and nuclear DNA (nDNA)-encoded oxidative phosphorylation (OXPHOS) gene expression in healthy and diabetic individuals, and in newborn but not in adult mice. Insulin gene expression was elevated in beta cells with higher mtDNA gene expression in humans and in young mice. Such human beta cell populations also diverged in mitochondrial RNA mutational repertoire, and in their selective signature, thus implying the existence of two previously overlooked distinct and conserved beta cell populations. While applying our approach to human alpha cells, two sub-populations of cells were identified which diverged in mtDNA gene expression, yet these cellular populations did not consistently diverge in nDNA OXPHOS genes expression, nor did they correlate with the expression of glucagon, the hallmark of alpha cells. Thus, pancreatic beta cells within an individual are divided into distinct groups with unique metabolic-mitochondrial signature.
Field evaluation of two mosquito traps in Zhejiang Province, China
Authors: Hou Juan , Wu Yinping , Mao Zhiyuan , Zhu Xinhong , Wu Yuyan , Liu Qinmei , Wang Jinna , Li Tianqi , Gong Zhenyu , Dong Xuanjun , Wang Zhen
Published: January 2021

Mosquito-borne Diseases are a common but severe public health threat. However, there is a lack of consensus on the effect of different mosquito trapping devices in China. This study firstly compared the BGM trap with the CDC light trap, commonly used in Chinese mosquito surveillance. Field trials of traps' efficiency were conducted in Yiwu city, China, from May 21st, 2018 to November 31st, 2018. Sixty-five comparisons were completed in five different biotopes (an urban residential area, a rural residential area, a park, a hospital, and a pig shelter). Concerning the number of mosquitoes per trap, the BGM trap outperformed three out of five biotopes. In contrast, the CDC light trap only showed better performance in the pig shelter. For specific species, the BGM trap outperformed in capturingAe. albopictus, while the CDC light trap caught significantly moreCx. tritaeniorhynchus. RegardingAe. albopictusandCx. pipienss.l.surveillance, the BGM trap is more suitable. The BGM trap shows significantly higher or similar efficiency than the CDC light trap in trapping common mosquito species in China, except in the pig shelter. Therefore, we recommend that Chinese researchers and public health practitioners use the BGM trap in future mosquito surveillance.
Author Correction: High-performance vector bending and orientation distinguishing curvature sensor based on asymmetric coupled multi-core fibre
Authors: Arrizabalaga Oskar , Sun Qi , Beresna Martynas , Lee Timothy , Zubia Joseba , Pascual Javier Velasco , de Ocáriz Idurre Sáez , Schülzgen Axel , Antonio‑Lopez Jose Enrique , Amezcua‑Correa Rodrigo , Villatoro Joel , Brambilla Gilberto
Published: January 2021

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Asymmetric air-sea heat flux response and ocean impact to synoptic-scale atmospheric disturbances observed at JKEO and KEO buoys
Authors: Tomita Hiroyuki , Cronin Meghan F. , Ohishi Shun
Published: January 2021

This study aims to identify patterns of surface heat fluxes, and corresponding surface ocean responses, associated with synoptic-scale atmospheric events and their modulation on seasonal time scales. In particular, northerly and southerly wind events associated with atmospheric disturbances were analyzed using high-temporal resolution time-series data from two moored buoys (JKEO: 2007–2010 and KEO: 2004–2019) north and south of the Kuroshio Extension current. Although each synoptic-scale wind event generally impacted both sites, the composite surface heat flux was larger at the northern site, especially for northerly events. Both types of wind events were observed throughout the year, with a minimum during June-July–August. Northerly wind events tended to be accompanied by lowered air-temperature, while southerly events tended to have elevated air-temperature relative to the previous three days. The resulting anomalous surface heat loss was asymmetric, with larger changes in northerly events compared to the southerly events. A large and significant ocean response of − 0.28 to − 0.46 K (p-value < 0.05) in SST was confirmed only for northerly events in spring–summer at the northern site, while smaller changes were found at the southern site. The results of this study suggest that sub-monthly air-sea interactions may affect seasonal variability and potentially climate change over longer timescales.
Development of phenotypic assays for identifying novel blockers of L-type calcium channels in neurons
Authors: Hagan Rebecca , Rex Elizabeth , Woody David , Milewski Monika , Glaza Thomas , Maher Michael P. , Liu Yi
Published: January 2021

L-type calcium channels (LTCCs) are highly expressed in the heart and brain and are critical for cardiac and neuronal functions. LTCC-blocking drugs have a long and successful record in the clinic for treating cardiovascular disorders. In contrast, establishment of their efficacy for indications of the central nervous system remains challenging given the tendency of existing LTCC drugs being functionally and mechanistically more selective for peripheral tissues. LTCCs in vivo are large macromolecular complexes consisting of a pore-forming subunit and other modulatory proteins, some of which may be neuro-specific and potentially harbor mechanisms for neuronal selectivity. To exploit the possibility of identifying mechanistically novel and/or neuro-selective blockers, we developed two phenotypic assays—a calcium flux-based primary screening assay and a patch clamp secondary assay, using rat primary cortical cultures. We screened a library comprised of 1278 known bioactive agents and successfully identified a majority of the potent LTCC-blocking drugs in the library. Significantly, we identified a previously unrecognized LTCC blocker with a novel mechanism, which was corroborated by patch clamp and binding studies. As such, these phenotypic assays are robust and represent an important step towards identifying mechanistically novel and neuro-selective LTCC blockers.
A numerical solution to the effects of surface roughness on water–coal contact angle
Authors: Li Chong , Zhang Jian , Han Jun , Yao Banghua
Published: January 2021

Coal dust is a great threat to coal mine workers' health and safety in coal mine production. Wet dust removal is one of the effective dust removal methods. As a solid, coal has different rough surfaces, which have a certain effect on the wetting effect of coal. In this paper, three coal samples with different surface wettability are used as the research objects. Phase-field interface tracking method is used to simulate the wetting of droplets on rough surfaces. From the simulation results, it can be concluded that the influence of the rough interface on the contact angle of the droplets is in accordance with the change rule described in the Wenzel model. As the roughness increases, the contact angle of the hydrophilic lignite surface gradually decreases. As the roughness increases, the contact angle of hydrophobic coking coal gradually increases. The change trend of the contact on the surface of weakly hydrophilic anthracite coal is the same as that of lignite. Due to the local and global differences, the contact angles obtained from the numerical model are slightly different from the values calculated from the Wenzel model.
Incorporation of tetracarboxylate ions into octacalcium phosphate for the development of next-generation biofriendly materials
Authors: Yokoi Taishi , Goto Tomoyo , Hara Mitsuo , Sekino Tohru , Seki Takahiro , Kamitakahara Masanobu , Ohtsuki Chikara , Kitaoka Satoshi , Takahashi Seiji , Kawashita Masakazu
Published: January 2021

Octacalcium phosphate (OCP; Ca8(HPO4)2(PO4)4 ∙ 5H2O) is a precursor of hydroxyapatite found in human bones and teeth, and is among the inorganic substances critical for hard tissue formation and regeneration in the human body. OCP has a layered structure and can incorporate carboxylate ions into its interlayers. However, studies involving the incorporation of tetracarboxylic and multivalent (pentavalent and above) carboxylic acids into OCP have not yet been reported. In this study, we investigate the incorporation of pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid), a type of tetracarboxylic acid, into OCP. We established that pyromellitate ions could be incorporated into OCP by a wet chemical method using an acetate buffer solution containing pyromellitic acid. The derived OCP showed a brilliant blue emission under UV light owing to the incorporated pyromellitate ions. Incorporation of a carboxylic acid into OCP imparted new functions, which could enable the development of novel functional materials for biomedical applications.
Facile PEG-based isolation and classification of cancer extracellular vesicles and particles with label-free surface-enhanced Raman scattering and pattern recognition algorithm
Authors: Yin Pengju , Li Guoqian , Zhang Baoyue , Farjana Haque , Zhao Lei , Qin Hongwei , Hu Bo , Ou Jianzhen , Tian Jie
Published: January 2021

Extracellular vesicles and particles (EVPs), which contain the same surface proteins as their mother cells, are promising biomarkers for cancer liquid biopsy.
Metabolism in action: stable isotope probing using vibrational spectroscopy and SIMS reveals kinetic and metabolic flux of key substrates
Authors: Chisanga Malama , Muhamadali Howbeer , McDougall Danielle , Xu Yun , Lockyer Nicholas , Goodacre Royston
Published: January 2021

Raman and infrared are used to measure dynamics in bacterial metabolism by employing stable isotope probing with temporal acquisition. The work is complemented by SIMS for confirmation of 13C incorporation into bacterial biomass.
A direct synthesis of carboxylic acidsviaplatinum-catalysed hydroxycarbonylation of olefins
Authors: Schneider Carolin , Franke Robert , Jackstell Ralf , Beller Matthias
Published: January 2021

A selective platinum-catalysed hydroxycarbonylation of aliphatic olefins has been achieved.
Palm oil consumption and its repercussion on endogenous fatty acids distribution
Authors: Li Ruizhi , Cao Chen , Zheng Zhaojun , Yang Xiaoyan , Tan Chin Ping , Xu Yongjiang , Liu Yuanfa
Published: January 2021

The consumption of saturated lipids in combination with a sedentary lifestyle increases the risk of obesity and metabolic syndrome.
Distributed colorimetric interferometer for mapping the pressure distribution in a complex microfluidics network
Authors: Zhu Xiongfeng , Man Tianxing , Tan Xing Haw Marvin , Chung Pei-Shan , Teitell Michael A. , Chiou Pei-Yu
Published: January 2021

A distributed color interferometry-based pressure-sensing platform with more than 10 000 pressure sensing spots spanning a 1 cm2cross-sectional area.
Budded baculoviruses as a receptor display system to quantify ligand binding with TIRF microscopy
Authors: Laasfeld Tõnis , Ehrminger Robin , Tahk Maris-Johanna , Veiksina Santa , Kõlvart Karl Rene , Min Mart , Kopanchuk Sergei , Rinken Ago
Published: January 2021

Characterization of ligand binding properties to receptors and other membrane proteins in budded baculovirus nanoparticles using TIRF microscopy.
Mechanism orienting structure construction of electrodes for aqueous electrochemical energy storage systems: a review
Authors: Li Tian , Qin TingTing , Yang ChangLin , Zhang WenLi , Zhang Wei
Published: January 2021

Comprehensive structural design engineering & some suggestions for fine modifications of electrode materials at the atomic and molecular levels are proposed to combine the advantages of supercapacitor- & battery-type materials for designing electrode materials for AEESSs.
Palladium-catalyzed dearomative cyclocarbonylation of allyl alcohol for the synthesis of quinolizinones
Authors: Xu Pengcheng , Qian Bo , Qi Zaojuan , Gao Bao , Hu Bin , Huang Hanmin
Published: January 2021

Palladium-catalyzed dearomative cyclocarbonylation of allyl alcohol for the synthesis of quinolizinones with potential bioactivity has been developed for the first time.
Light-induced efficient and residue-selective bioconjugation of native proteins via indazolone formation
Authors: Guo An-Di , Wu Ke-Huan , Chen Xiao-Hua
Published: January 2021

The generality was demonstrated for rapid functionalization of native proteins via light-induced lysine-selective indazolone formation in vitro and in vivo, which suggests a new avenue to bioconjugation, medicinal chemistry and chemical biology.
Metal organic chemical vapour deposition regrown large area GaN‐on‐GaN current aperture vertical electron transistors with high current capability
Authors: Doering Philipp , Driad Rachid , Reiner Richard , Waltereit Patrick , Mikulla Michael , Ambacher Oliver
Published: January 2021

In this work, a large area current aperture vertical electron transistor (CAVET) is fabricated on bulk GaN substrates grown by metal organic chemical vapour deposition (MOCVD). The current blocking layer (CBL) is formed by low dose Mg‐implantation to allow for MOCVD regrowth under standard growth conditions, which simultaneously serves as an in‐situ annealing process. Small transistors are evaluated regarding gate‐aperture overlap (LGAP) to derive a robust layout in order to suppress source‐drain leakage. Optimized gate‐aperture dimensions are adopted and combined with a common comb structure design and the established gate‐source module of the lateral HEMT to demonstrate a large area CAVET comb structure. The multi‐finger device exhibits an on‐state resistance of RON = 2.15 Ω and a chip area of A = 2 × 2 mm². The large area CAVET reveals a maximum drain current of ID,MAX = 20.1 A at a drain‐source voltage of VDS = 45 V, corresponding to a power of P = 900 W.
Spin-speed independent thickness and molecular adsorption behaviour of polyelectrolyte multilayers
Authors: Boranna Rakshith , Nataraj Chandrika Thondagere , Jagannath Raviprasad Kogravalli , Pahal Suman , Varma Manoj M. , Prashanth Gurusiddappa R.
Published: January 2021

The science behind the build-up mechanism of polyelectrolyte multilayers is important for developing devices for various engineering applications. Here we, study the dependency of thickness of polyelectrolyte multilayer films, fabricated using spin-assisted layer-by-layer self-assembly of polyelectrolytes technique, with respect to varying spin-speed while keeping all other parameters of the fabrication process-window constant. The thickness measurements were performed using variable angle spectroscopic ellipsometry and atomic force microscopy. The experimentally observed results were validated mathematically using a Flory type theory. In addition, the bio-molecular adsorption studies on these polyelectrolyte multilayer films fabricated at various spin-speeds, were also quantitatively analyzed using fluorescence microscopy studies. It was seen that the effect of spin-speed on the thickness of polyelectrolyte multilayers was negligible. In addition, it was also observed that the bio-molecular adsorption modalities onto these substrates were also independent of the spin-speed. This finding prompts to develop low-cost alternative technologies for various biomedical engineering applications, like functionalized substrates for centrifugal assay for fluorescence-based cell adhesion, wherein stability of films against strong mechanical forces generated during spinning can play an important role.
Développement et maintenance du système neuromusculaire
Authors: Guillermin Camille , Bouchet Mathilde , Garcès Alain , Enriquez Jonathan
Published: January 2021

Diseases of the locomotor system are at the origin of disabilities with severe social and economic consequences. The study of the neuromuscular system development and maintenance has become a key challenge for the scientific community in order to design efficient therapies. My thesis project aims to elucidate the mechanisms at the origin of the communication between motoneuron axons and their muscle targets in order to understand how specific innervations are generated during development and maintained during adulthood. The first part of the project will address the understanding of the mechanisms controlling the specific muscle-axon recognition during development. I will perform live imaging and fixed tissues experiments to visualize and understand the development of myoblasts and motoneurons at the same time. Then, I will perform transcriptomic experiments to discover molecules playing a role in the specific axon-muscle recognition. The second part of the project is meant to elucidate the mechanism controlling the system maintenance in the adult. To answer this question I will study the function of morphological transcription factors in adulthood, which are known as transcription factors controlling the morphology of motoneurons during development. To conclude, this project will lead to novel biological concepts that will increase our fundamental knowledge on developmental biology. Understanding the mechanisms that specify the muscle innervation will allow to find efficient ways to tackle neuromuscular diseases.
Trachéotomie chez les enfants atteints de maladies neuromusculaires et scolarisation en milieu ordinaire
Authors: Bonraisin Laure , Destremaut Cécile , Lagrue Emmanuelle
Published: January 2021

Les enfants atteints de maladies neuromusculaires nécessitent parfois une assistance ventilatoire au long cours. Parmi les techniques employées, la ventilation sur trachéotomie reste par définition invasive et à même de mettre en péril l’intégration scolaire du jeune malade.
La dystrophie musculaire des ceintures de type R9 liée au gène FKRP
Authors: Villar Quiles Rocío Nur , Richard Isabelle , Bouchet-Seraphin Céline , Stojkovic Tanya
Published: January 2021

Les mutations du gène FKRP codant la fukutin-related protein (FKRP) sont à l’origine d’un large éventail de myopathies allant de formes sévères de dystrophies musculaires congénitales associées à des anomalies structurales du système nerveux central, jusqu’à des tableaux de myalgies à l’effort ou d’hyperCKémie asymptomatique, en passant par une forme de dystrophie musculaire des ceintures, la LGMD-R9 (ex-LGMD-2I), pour limb girdle muscular dystrophy récessive de type R9. La LGMD-R9 se caractérise par un déficit proximal des ceintures prédominant initialement aux membres inférieurs, avec une atteinte respiratoire et cardiaque pouvant conditionner le pronostic vital. Le taux sérique de CPK est nettement élevé et s’accompagne, sur la biopsie musculaire, d’une formule dystrophique associée à une réduction de la glycosylation de l’α-dystroglycane visible en immunomarquage et par immunoblot. L’IRM musculaire montre typiquement une atteinte des muscles proximaux (iliopsoas, adducteurs, grands fessiers, quadriceps) avec une relative préservation des muscles de la loge antérieure des cuisses (gracilis et sartorius). L’analyse génétique, par séquençage spécifique du gène FKRP ou d’un panel regroupant l’ensemble des gènes impliqués dans la glycosylation de l’α-dystroglycane, ou bien d’un panel plus large de gènes, confirme généralement le diagnostic, la mutation la plus fréquente étant le faux-sens p.(Leu276Ile). Actuellement, le traitement de la LGMD-R9 est symptomatique, requérant une approche pluridisciplinaire. Une étude prospective d’histoire naturelle de la maladie est en cours en Europe (GNT-015-FKRP). Des approches thérapeutiques inédites sont envisagées, telles que la thérapie génique médiée par des vecteurs dérivés du virus adéno-associé (AAV). Celle-ci est efficace dans les modèles animaux, permettant une correction des défauts de glycosylation de l’a-dystroglycane et une augmentation de sa capacité de liaison à la matrice extracellulaire. En parallèle, des études précliniques ont montré, dans un modèle animal, l’efficacité du ribitol, un pentose alcool retrouvé dans des composés naturels, ce qui a conduit à un essai de phase I dont le développement clinique est en cours.
Les sarcoglycanopathies
Authors: Fernández-Eulate Gorka , Leturcq France , Laforêt Pascal , Richard Isabelle , Stojkovic Tanya
Published: January 2021

Les sarcoglycanopathies font partie des dystrophies musculaires des ceintures (LGMD) autosomiques récessives et représentent la troisième cause la plus fréquente d’entre elles. Elles sont consécutives à un déficit d’un des sarcoglycanes α, β, γ, ou δ. La présentation clinique habituelle est celle d’une atteinte symétrique des muscles des ceintures pelvienne et scapulaire ainsi que du tronc, associée à une atteinte cardiorespiratoire plus ou moins sévère et une élévation franche des créatine-phospho-kinases (CPK). Les premiers symptômes apparaissent au cours de la première décennie, la perte de la marche survenant souvent au cours de la deuxième décennie. Les lésions sont de type dystrophique sur la biopsie musculaire. Il s’y associe une diminution ou une absence d’immunomarquage du sarcoglycane correspondant au gène muté, et dans une moindre mesure des trois autres sarcoglycanes associés. De nombreuses mutations ont été rapportées dans les quatre gènes impliqués et quelques-unes d’entre elles sont prépondérantes dans certaines populations. à ce jour, il n’existe pas de traitement curatif ce qui n’empêche pas de voir se développer de nombreux essais cliniques, notamment en thérapie génique.
Calpaïnopathies
Authors: Malfatti Edoardo , Richard Isabelle
Published: January 2021

Les calpaïnopathies sont des dystrophies musculaires des ceintures héréditaires, le plus souvent avec une transmission autosomique récessive (AR). Des formes autosomiques dominantes (AD) de présentation moins sévère sont de plus en plus rapportées. Les calpaïnopathies avec mutations autosomiques récessives du gène de la calpaïne 3(CAPN3)sont associées à la dystrophie musculaire des ceintures de type R1 (OMIM 253600) ou LGMD-2A, selon l’ancienne nomenclature. La LGMD-R1 est la plus fréquente de toutes les formes de LGMD, sa prévalence étant estimée entre 10 et 70 cas par million d’habitants. Il existerait ainsi entre 670 et 4 200 patients atteints de LGMD-R1 en France. Les patients présentent une myopathie proximale symétrique et axiale se manifestant entre la première et la deuxième décennie. L’évolution est variable. Le taux de Créatine-Phospho-Kinase sérique est élevé et il n’y a pas d’atteinte cardiaque. Au niveau thérapeutique, la forme autosomique récessive de calpaïnopathie se prête à des stratégies de remplacement de gène. La viabilité d’un transfert de calpaïne 3 médié par un AAV recombinant a été démontrée dans des modèles animaux et un passage en clinique est attendu dans les prochaines années. En attendant, des études d’histoire naturelle sont nécessaires afin de préparer les futurs essais cliniques.
New exponential dispersion models for count data: the ABM and LM classes
Authors: Bar-Lev Shaul K. , Ridder Ad
Published: January 2021

In their fundamental paper on cubic variance functions (VFs), Letac and Mora (The Annals of Statistics, 1990) presented a systematic, rigorous and comprehensive study of natural exponential families (NEFs) on the real line, their characterization through their VFs and mean value parameterization. They presented a section that for some reason has been left unnoticed. This section deals with the construction of VFs associated with NEFs of counting distributions on the set of nonnegative integers and allows to find the corresponding generating measures. As EDMs are based on NEFs, we introduce in this paper two new classes of EDMs based on their results. For these classes, which are associated with simple VFs, we derive their mean value parameterization and their associated generating measures. We also prove that they have some desirable properties. Both classes are shown to be overdispersed and zero inflated in ascending order, making them as competitive statistical models for those in use in both, statistical and actuarial modeling. To our best knowledge, the classes of counting distributions we present in this paper, have not been introduced or discussed before in the literature. To show that our classes can serve as competitive statistical models for those in use (e.g., Poisson, Negative binomial), we include a numerical example of real data. In this example, we compare the performance of our classes with relevant competitive models.
Faraday waves under perpendicular electric field and their application to the walking droplet phenomenon
Authors: Fernández-Mateo Raúl , Pérez Alberto T.
Published: January 2021

Vertically oscillating fluid surfaces have been a subject extensively studied in the past, as well as surface instabilities produced by electrohydrodynamic waves in similar configurations. In the present work, the unification of both effects and their consequences on the stability of the surface. Given the versatility of electromagnetic fields, application to the phenomenon of walking droplets is suggested; the dispersion relation and bouncing regimes of and the force on the droplets are revisited, and feasible experimental configurations are proposed.
Effects of surface topography on low Reynolds number droplet/bubble flow through a constricted passage
Authors: Singla Aditya , Ray Bahni
Published: January 2021

This paper is an attempt to study the effects of surface topography on the flow of a droplet (or a bubble) in a low Reynolds number flow regime. Multiphase flows through a constricted passage find many interesting applications in chemistry and biology. The main parameters that determine the flow properties such as flow rate and pressure drop and govern the complex multiphase phenomena such as drop coalescence and breakup in a straight channel flow are the viscosity ratio, droplet size, and ratio of the viscous forces to the surface tension forces (denoted by the capillary number). However, in flow through a constricted passage, in addition to the above-mentioned parameters, various other geometric parameters such as constriction ratio, length, shape of the constriction, phase angle, and spacing between the constrictions also start playing an important role. Most of the studies done on the problem of drop flow through a constricted passage have aimed to understand the role of physical parameters, with some studies extending their analysis to understand the variation of one or two geometric parameters. However, no study could be found, which explicitly evaluates the role of surface topography. An attempt has been made to unify the current literature as well as analyze the effect of the geometric parameters by understanding the physics and mechanisms involved. The non-dimensional numbers that govern this problem are then identified using the scaling analysis.
Multiphysics modeling of the initiating capability of detonators. II. Booster initiation
Authors: Ioannou Eleftherios , Nikiforakis Nikolaos
Published: January 2021

Detonators are explosive devices used for the initiation of secondary explosives in commercial and military applications. They are characterized by their initiating capability, which is a critical factor for their safe and effective use but challenging to assess accurately. In this two-part study, we employ numerical simulations to investigate the blast wave generated by detonators and examine their initiating capability. The first part follows the European underwater test, which evaluates detonators in isolation (direct method). The second part, presented here, investigates detonators placed within a receiving explosive charge (indirect method). Specifically, the detonator is placed inside a booster device, which contains secondary explosives and together forms an initiating system used to ignite mining blastholes. The physical system is modeled using a multiphysics methodology to accurately capture the response of the materials present in the configuration (explosives, metals, and fluids). The reactive model is extended to account for shock desensitization where explosives become more difficult to initiate after the passage of weak shock waves. The variability of the blast wave generated by detonators, observed in the first part of the study, can lead to partial desensitization resulting in pockets of unreacted explosives, which inhibit booster initiation and performance. The computational implementation is extensively validated and calibrated against the experiment before being employed for the study of booster initiation by a range of detonators. Results show that the booster is susceptible to shock desensitization, which occurs in varying degrees for different types of detonators and can significantly impact the performance of the initiating system.
Self-biased magneto-optical films based on CoFe2O4–silica nanocomposite
Authors: Choueikani F. , Jamon D. , Neveu S. , Blanc-Mignon M.-F. , Lefkir Y. , Royer F.
Published: January 2021

Composite thin films made of cobalt ferrite nanoparticles embedded in silica/zirconia sol-gel matrix are presented, and their versatility is illustrated through the impact of the nanoparticle features on the films’ final properties. The intrinsic magneto-optical potentiality of the nanoparticles is especially given by a peak around 1550 nm in the spectra of both the Faraday rotation and the magneto-optical figure of merit. These nanoparticles are inserted in the liquid preparation of a sol-gel host matrix, which is coated on a glass substrate at soft temperature. SEM and optical analysis show the absence of nanoparticle aggregates and defects into thin films and prove the ability of these films to be used as a guiding layer for photonic integration. The dispersion in the host matrix and the integration on a substrate do not affect the merit factor of the material. The specific Faraday rotation of the films is about 300°/cm for a volume fraction of nanoparticles of 1.5%, and it possesses a hysteresis loop. Its dependence on the nanoparticle mean size offers the possibility to achieve self-biased behavior. In addition, a magnetic field applied during the coating promotes an alignment of the magnetic easy axis of the nanoparticles along a preferential direction. It allows increasing even more the remanent magneto-optical effect and also reducing the birefringence and reaching a TE/TM phase matching of the film guided modes. It gives a way to tune these two parameters that play a crucial role in magneto-optical devices.
Wertheim’s thermodynamic perturbation theory with double-bond association and its application to colloid–linker mixtures
Authors: Howard Michael P. , Sherman Zachary M. , Milliron Delia J. , Truskett Thomas M.
Published: January 2021

We extend Wertheim’s thermodynamic perturbation theory to derive the association free energy of a multicomponent mixture for which double bonds can form between any two pairs of the molecules’ arbitrary number of bonding sites. This generalization reduces in limiting cases to prior theories that restrict double bonding to at most one pair of sites per molecule. We apply the new theory to an associating mixture of colloidal particles (“colloids”) and flexible chain molecules (“linkers”). The linkers have two functional end groups, each of which may bond to one of several sites on the colloids. Due to their flexibility, a significant fraction of linkers can “loop” with both ends bonding to sites on the same colloid instead of bridging sites on different colloids. We use the theory to show that the fraction of linkers in loops depends sensitively on the linker end-to-end distance relative to the colloid bonding-site distance, which suggests strategies for mitigating the loop formation that may otherwise hinder linker-mediated colloidal assembly.
Modeling and computation for non-equilibrium gas dynamics: Beyond single relaxation time kinetic models
Authors: Xu Xiaocong , Chen Yipei , Xu Kun
Published: January 2021

Many kinetic relaxation models have been proposed for the study of rarefied flows. Based on the single relaxation time model, a discrete velocity method-based unified gas-kinetic scheme (UGKS) has been constructed. The UGKS models the gas dynamics on the discretized space directly on account of accumulating flow evolution from particle transport and collision within a time step. Under the UGKS framework, a unified gas-kinetic wave-particle (UGKWP) method has been further developed for non-equilibrium flow simulation, where the time evolution of the gas distribution function is composed of analytical wave and individual particles. In the highly rarefied regime, the flow evolution is mainly described by the particle transport and collision. Because of the use of single relaxation time for particle collision, there is a noticeable discrepancy between the UGKWP solution and the full Boltzmann or direct simulation Monte Carlo (DSMC) result, such as the temperature distribution inside a shock layer at high Mach numbers. In this Letter, a modification of the particle collision time according to the particle velocity will be implemented in the UGKWP. As a result, the new model greatly improves the performance of the UGKWP in the capturing of non-equilibrium flows. There is an excellent match between UGKWP and DSMC or Boltzmann solution in the highly rarefied regime. In the continuum flow regime, due to the absence of particles, the modification of the particle collision time will not take effect and the UGKWP will get back to the hydrodynamic Navier–Stokes flow solver with correct dissipative coefficients at small cell Knudsen numbers.
Impurity effect on drift-resistive-inertial ballooning mode and associated transport at the edge of tokamak plasmas
Authors: Xu J. Q. , Peng X. D. , Hao G. Z. , Qu H. P. , Chen W. , Li J. Q.
Published: January 2021

A collisional multi-ion-species fluid model is developed for the description of drift-resistive-inertial ballooning modes (DRIBMs) with collision rates calculated depending on the Spitzer–Härm transport coefficients. Numerical results have shown that the impurity effect on the linear stability of DRIBM and corresponding transport strongly depends on the impurity species, impurity fraction fz (fz = nz/ne, where nz and ne are impurity and electron densities, respectively), impurity density gradient (R/Lnz), and the type of the driving force of the DRIBM. The density gradient driven DRIBM (εn-RBM) is usually stabilized by light impurity while destabilized by heavy impurity at relatively small values of R/Lnz as fz increases. For large R/Lnz, the impurity will destabilize the εn-RBM regardless of the impurity species. The electron temperature gradient driven DRIBM (ηe-RBM) is destabilized with both the increase in fz and R/Lnz. A small fraction of light impurity has destabilizing effect on the ion temperature gradient driven DRIBM (ηi-RBM), and a large fz shows a stabilizing effect. Moreover, the heavy impurity species will destabilize the ηi-RBM. The features of the DRIBM driven by the coexistence of ion and electron temperature gradients share many similarities with the ηe-RBM as the electron temperature is a strong driving force of DRIBM. The ion particle transport induced by the DRIBM usually peaks at certain values of fz which is further enhanced with increasing R/Lnz for the case of light impurity, while it usually becomes larger as fz and R/Lnz increase in the presence of heavy impurity. The impurity transport is enhanced with the increasing of impurity fraction and the gradient in general. The dependence of impurity density peaking factor on impurity charge number and concentration is also discussed. These results will promote the understanding of the edge turbulent transport in the presence of impurities and provide controlling mechanisms by seeded impurity injection.
Competitive formation of intercalated versus supported metal nanoclusters during deposition on layered materials with surface point defects
Authors: Han Yong , Lii-Rosales Ann , Tringides Michael C. , Evans James W.
Published: January 2021

Intercalated metal nanoclusters (NCs) can be formed under the surface of graphite after sputtering to generate surface “portal” defects that allow deposited atoms to reach the subsurface gallery. However, there is a competition between formation of supported NCs on top of the surface and intercalated NCs under the surface, the latter only dominating at sufficiently high temperature. A stochastic model incorporating appropriate system thermodynamics and kinetics is developed to capture this complex and competitive nucleation and growth process. Kinetic Monte Carlo simulation shows that the model captures experimental trends observed for Cu and other metals and reveals that higher temperatures are needed to facilitate detachment of atoms from supported NCs enabling them to reach the gallery.
Predicting bond-currents in polybenzenoid hydrocarbons with an additivity scheme
Authors: Paenurk Eno , Feusi Stefan , Gershoni-Poranne Renana
Published: January 2021

We report on the construction and application of a new bond-current additivity scheme for polybenzenoid hydrocarbons. The method is based on identification of the smaller substructures contained in the system, up to tricyclic subunits. Thus, it enables the prediction of any cata-condensed unbranched polybenzenoid hydrocarbon, using a library consisting of only four building blocks. The predicted bond-currents can then be used to generate Nucleus Independent Chemical Shift (NICS) values, the results of which validate previous observations of additivity with NICS-XY-Scans. The limitations of the method are probed, leading to clearly delineated and apparently constant error boundaries, which are independent of the molecular size. It is shown that there is a relationship between the accuracy of the predictions and the molecular structure and specific motifs that are especially challenging are identified. The results of the additivity method, combined with the transparent description of its strengths and weaknesses, ensure that this method can be used with well-defined reliability for characterization of polybenzenoid hydrocarbons. The resource-efficient and rapid nature of the method makes it a promising tool for screening and molecular design.
Nonlinear ultrasonic guided waves—Principles for nondestructive evaluation
Authors: Lissenden Cliff J.
Published: January 2021

Research into the use of nonlinear ultrasonic guided waves for nondestructive evaluation is expanding at a high rate because of the great potential benefit that they possess for early detection of material degradation. However, development of inspection and testing strategies is complicated because (i) the underlying physical principles are complex, (ii) there is a broad spectrum of possible solutions but only a limited number that have been shown to be effective, and (iii) the nonlinearity is weak and thus its measurement is challenging. This Tutorial aims to provide a foundation for researchers and technology-transitioners alike, to advance the application of nonlinear ultrasonic guided waves and ultimately transform how the service lives of structural systems are managed. The Tutorial focuses on the physical principles of nonlinear ultrasonic guided waves leading to the so-called internal resonance conditions that provide a means for selecting primary waves that generate cumulative secondary waves. To detect material degradation, we are primarily interested in nonlinearity stemming from the material itself, which is represented as hyperelastic. For the special case of plates, internal resonance points have been identified and case studies are presented to illustrate some of the applications. The Tutorial has one new result not published in a research paper; finite element simulation of energy transfer from shear-horizontal primary waves to symmetric Lamb waves at the second harmonic.
Epitaxial strain tunable conductivity and charge transport of Ba0.6La0.4TiO3 thin films deposited by pulsed laser deposition
Authors: Zhang Aihua , Li Qiang , Wang Dao , Zhang Yan , Li Yushan , Zeng Min , Lu Xubing , Liu J.-M.
Published: January 2021

In this work, Ba0.6La0.4TiO3 (BLTO) thin films with a thickness of ∼30 nm were deposited by pulsed laser deposition on four different types of substrates, [MgO(100), LaAlO3(100), DyScO3(110), and GdScO3(110)], and their structures, charge transport behaviors, and related transport mechanisms were comprehensively explored. X-ray diffraction characterization revealed that all the BLTO films are epitaxially grown with strain ranging from ∼+0.65% to ∼−0.63%. All the films show a distinct semiconductor–metal transition behavior, and the transition temperature (TSM) decreases upon increasing the compressive strain. Their conductivities follow successively the variable-range hopping and small-polaron hopping mechanisms below TSM, and thermal excitation mechanism above TSM, while the corresponding temperature ranges are substrate dependent. Finally, Hall effect measurements confirmed that all the BLTO films possess semiconductor conduction behaviors, and the epitaxial strain can enhance carrier density. These results demonstrate that epitaxial strain can effectively tune the charge transport behaviors of BLTO thin films.
Underpinned exploration for magnetic structure, lattice dynamics, electronic properties, and disproportionation of yttrium nickelate
Authors: Du Jinglian , Shang Shun-Li , Wang Yi , Zhang Ang , Xiong Shoumei , Liu Feng , Liu Zi-Kui
Published: January 2021

Magnetic behavior and disproportionation effect of nickelates are closely related to the nature of their ground state. In the present work, the magnetic structure, lattice dynamics, electronic properties, and disproportionation effect of yttrium nickelate (YNiO3) in its ground state P21/n structure were investigated by first-principles and phonon calculations based on density functional theory (DFT). The strong correlated interactions were treated by the DFT + U approach and the meta-generalized-gradient approximation approach implemented under the strongly constrained appropriately normed functional. The S-type antiferromagnetic insulating ground state of YNiO3 was captured well by both approaches. The disproportionation effect is quantitatively characterized through the Born effective charge, indicating the ligand-hole picture of Ni2+ → Ni2−δ+ Ni2+δ with δ = 0.3. The predicted phonon frequency at the Γ point agrees well with the measured value from infrared experiments, including the longitudinal and transverse optical splitting. The analysis based on stretching force constants indicated that the interaction between Ni and O atoms in the small nonmagnetic NiO6 octahedral clusters is stronger than that in the large magnetic NiO6 octahedral clusters.
An improved magnetostriction model of silicon steel considering the saturated magnetic domain wall movement
Authors: Ben Tong , Chen Fangyuan , Chen Long , Yan Rongge
Published: January 2021

To obtain the deformation characteristic of silicon steel with yoke clamping applied under an alternating magnetic field, a stress-dependent magnetostriction model of silicon steel must be constructed. Due to the magnetic domain’s rotation and the magnetic domain wall movement with stress applied, the material’s magnetostrictive deformation will reverse and saturate in both magnitude and direction. Therefore, the saturated magnetic domain wall movement effect must be considered in the stress-dependent magnetostriction model. Firstly, a hysteresis stress-dependent magnetostriction model based on the Jiles-Atherton (J-A) model and Zheng-Liu (Z-L) model is proposed. Then, the magnetostrictive deformation curves of the non-oriented silicon steel with external stresses are measured. The magnetic field and deformation parameters that control the saturated magnetic domain wall movement are extracted and applied to the model. Finally, the magnetostrictive loops with the magnetic field under varying stress are obtained based on the proposed model. The proposed model’s effectiveness and accuracy are verified by comparing the measurement results with the simulation results.
Ac magnetoresistance and microwave absorption in Sr2FeMoO6
Authors: Das Rajasree , Chaudhuri Ushnish , Mahendiran Ramanathan
Published: January 2021

This work investigates the microwave absorption property of the ferrimagnetic double perovskite, Sr2FeMoO6 (SFMO) using two different methods: magnetoimpedance (MI) and lock-in based broadband magnetic resonance detection. In the MI method, radio frequency (rf) current (f = 0.001 to 2.8 GHz) is injected into the sample. When dc magnetic field is swept, rf resistance exhibits a single sharp peak centred at H = 0 for f < 0.1 MHz. As f increases, the peak at H = 0 transforms into a dip accompanied by symmetrical double peaks at H = ±HP, which we attribute to the ferromagnetic resonance within the grains. HP increases with increasing frequency of the current. In the lock-in based broadband method the sample, placed on top of a coplanar waveguide, experiences an intense microwave magnetic field from the waveguide, and the field derivative of microwave power absorption is measured as the dc magnetic field is swept. Correlation between MI and microwave power absorption is shown. Landé g factors obtained from both the measurements are close, equal to 2.085, which implies the presence of Fe3+ cations. Large ac magnetoresistance in SFMO compared to its dc value, dominated by the dynamics of transverse permeability and ferromagnetic resonance within grains could be exploited for high-frequency device applications.