bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon dioxide and water incorporation mechanisms in SrFeO3−δ phases: a computational study
Authors: Ford L. J. , Slater P. R. , Christie J. K. , Goddard P.
Published: October 2020

With a higher propensity for low temperature synthesis routes along with a move toward lower solid oxide fuel cell operating temperatures, water and carbon dioxide incorporation in strontium ferrite is of importance.
Dynamics in the BMIM PF6/acetonitrile mixtures observed by femtosecond optical Kerr effect and molecular dynamics simulations
Authors: Polok Kamil , Beisert Matthieu , Świątek Adam , Maity Nishith , Piatkowski Piotr , Gadomski Wojciech , Miannay François Alexandre , Idrissi Abdenacer
Published: October 2020

We have measured the the optical Kerr effect signal time evolution up to 4 ns for mixtures of BMIM PF6 ionic liquid and acetonitrile. Analysis was made in the time and frequency domains with help of molecular dynamics simulations.
The magnetism of titanium-defected undoped rutile TiO2: first-principles calculations
Authors: Dai Houmei , Li Xin , Cai Xiaolin , Wei Ran
Published: October 2020

The magnetic moments of O1, O3, O4, and O5 are shown to be different from those of O2 and O6.
Mechanism of the highly effective peptide bond hydrolysis by MOF-808 catalyst under biologically relevant conditions
Authors: Conic Dragan , Pierloot Kristine , Parac-Vogt Tatjana N. , Harvey Jeremy N.
Published: October 2020

DFT calculations provide insight into the speciation of the Zr6 nodes in MOF-808 in water, and reveal the detailed mechanism of its nanozymatic activity towards peptide bond hydrolysis in glycine–glycine as a model substrate.
Flexible energy generation and storage devices: focus on key role of heterocyclic solid-state organic ionic conductors
Authors: Vaghasiya Jayraj V. , Mayorga-Martinez Carmen C. , Pumera Martin
Published: October 2020

This review addresses the vital role of solid-state electrolytes to develop highly efficient, customizable flexible energy generation and storage devices.
Electronic structure influences on the formation of the solid electrolyte interphase
Authors: Song Weixin , Scholtis Elena Stein , Sherrell Peter C. , Tsang Deana K. H. , Ngiam Jonathan , Lischner Johannes , Fearn Sarah , Bemmer Victoria , Mattevi Cecilia , Klein Norbert , Xie Fang , Riley D. Jason
Published: October 2020

We elucidate how the electronic structure of battery electrodes can manipulate SEI film formation, morphology, and composition.
A unique space confined strategy to construct defective metal oxides within porous nanofibers for electrocatalysis
Authors: Hu Qi , Wang Ziyu , Huang Xiaowan , Qin Yongjie , Yang Hengpan , Ren Xiangzhong , Zhang Qianling , Liu Jianhong , He Chuanxin
Published: October 2020

A facile route is developed for the synthesis of defective metal oxide nanoparticles within porous nanofibers by capitalizing on the distinct pyrolysis behaviors of metal–organic compounds and polymers for efficient overall water splitting.
A water-based process for the surface functionalisation of ceramic fibres
Authors: Henry L. , Biscay N. , Huguet C. , Loison S. , Aymonier C.
Published: October 2020

This research work applied the hydrothermal process for the surface treatment of ceramic fibres in replacement of conventional process using strong acids.
Ultra-high rate capability of nanoporous carbon network@V2O5sub-micron brick composite as a novel cathode material for asymmetric supercapacitors
Authors: Jiao Yue , Wan Caichao , Wu Yiqiang , Han Jingquan , Bao Wenhui , Gao He , Wang Yaoxing , Wang Chengyu , Li Jian
Published: October 2020

A novel cathode material, composed of biomass-derived nanoporous carbon network and V2O5sub-micron bricks, delivers a high areal capacitance of 786 mF cm−2at 0.2 mA cm−2and superior cycling stability.
Gate-controlled spin–valley–layer locking in bilayer transition-metal dichalcogenides
Authors: Khani H. , Piri Pishekloo S.
Published: October 2020

We study the transport of spin, valley and layer pseudospin through a magnetoelectric barrier in AB-stacked bilayer TMDs and demonstrate an electrically controllable platform for multifunctional and ultra-high-speed logic devices.
Highly dispersed Pt species anchored onto NH2-Ce-MOFs and their derived mesoporous catalysts for CO oxidation
Authors: Guo Zeyi , You Qi , Song Lianghao , Sun Guoxin , Chen Guozhu , Li Cuncheng , Yang Xianfeng , Hu Xun , Jiang Xuchuan
Published: October 2020

Highly dispersed ultrafine platinum particles anchored onto mesoporous CeO2 were successfully prepared by coordinating Pt ions with –NH2 in NH2-Ce-MOFs.
Single molecule force spectroscopy reveals that a two-coordinate ferric site is critical for the folding of holo-rubredoxin
Authors: Li Jiayu , Li Hongbin
Published: October 2020

The folding pathway of holo-rubredoxin was elucidated by using optical tweezers-based single molecule force spectroscopy technique. The results revealed the critical importance of the two-coordinate ferric site for the folding of holo-rubredoxin.
In silicodecryption of serotonin–receptor binding: local non-covalent interactions and long-range conformational changes
Authors: Mondal Padmabati
Published: October 2020

This study is focused on identifying the main non-covalent interactions controlling the stability of serotonin–receptor complexes as well as the main conformational changes in the receptor due to serotonin–receptor binding.
Function and regulation of corin in physiology and disease
Authors: Dong Ningzheng , Niu Yayan , Chen Yue , Sun Shijin , Wu Qingyu
Published: October 2020

Atrial natriuretic peptide (ANP) is of major importance in the maintenance of electrolyte balance and normal blood pressure. Reduced plasma ANP levels are associated with the increased risk of cardiovascular disease. Corin is a type II transmembrane serine protease that converts the ANP precursor to mature ANP. Corin deficiency prevents ANP generation and alters electrolyte and body fluid homeostasis. Corin is synthesized as a zymogen that is proteolytically activated on the cell surface. Factors that disrupt corin folding, intracellular trafficking, cell surface expression, and zymogen activation are expected to impair corin function. To date, CORIN variants that reduce corin activity have been identified in hypertensive patients. In addition to the heart, corin expression has been detected in non-cardiac tissues, where corin and ANP participate in diverse physiological processes. In this review, we summarize the current knowledge in corin biosynthesis and post-translational modifications. We also discuss tissue-specific corin expression and function in physiology and disease.
Unveiling the cryo-EM structure of retromer
Authors: Chandra Mintu , Kendall Amy K. , Jackson Lauren P.
Published: October 2020

Retromer (VPS26/VPS35/VPS29) is a highly conserved eukaryotic protein complex that localizes to endosomes to sort transmembrane protein cargoes into vesicles and elongated tubules. Retromer mediates retrieval pathways from endosomes to the trans-Golgi network in all eukaryotes and further facilitates recycling pathways to the plasma membrane in metazoans. In cells, retromer engages multiple partners to orchestrate the formation of tubulovesicular structures, including sorting nexin (SNX) proteins, cargo adaptors, GTPases, regulators, and actin remodeling proteins. Retromer-mediated pathways are especially important for sorting cargoes required for neuronal maintenance, which links retromer loss or mutations to multiple human brain diseases and disorders. Structural and biochemical studies have long contributed to the understanding of retromer biology, but recent advances in cryo-electron microscopy and cryo-electron tomography have further uncovered exciting new snapshots of reconstituted retromer structures. These new structures reveal retromer assembles into an arch-shaped scaffold and suggest the scaffold may be flexible and adaptable in cells. Interactions with cargo adaptors, particularly SNXs, likely orient the scaffold with respect to phosphatidylinositol-3-phosphate (PtdIns3P)-enriched membranes. Pharmacological small molecule chaperones have further been shown to stabilize retromer in cultured cell and mouse models, but mechanisms by which these molecules bind remain unknown. This review will emphasize recent structural and biophysical advances in understanding retromer structure as the field moves towards a molecular view of retromer assembly and regulation on membranes.
ACE2 as therapeutic agent
Authors: Li Qiuhong , Grant Maria B. , Richards Elaine M. , Raizada Mohan K.
Published: October 2020

The angiotensin-converting enzyme 2 (ACE2) has emerged as a critical regulator of the renin–angiotensin system (RAS), which plays important roles in cardiovascular homeostasis by regulating vascular tone, fluid and electrolyte balance. ACE2 functions as a carboxymonopeptidase hydrolyzing the cleavage of a single C-terminal residue from Angiotensin-II (Ang-II), the key peptide hormone of RAS, to form Angiotensin-(1-7) (Ang-(1-7)), which binds to the G-protein–coupled Mas receptor and activates signaling pathways that counteract the pathways activated by Ang-II. ACE2 is expressed in a variety of tissues and overwhelming evidence substantiates the beneficial effects of enhancing ACE2/Ang-(1-7)/Mas axis under many pathological conditions in these tissues in experimental models. This review will provide a succinct overview on current strategies to enhance ACE2 as therapeutic agent, and discuss limitations and future challenges. ACE2 also has other functions, such as acting as a co-factor for amino acid transport and being exploited by the severe acute respiratory syndrome coronaviruses (SARS-CoVs) as cellular entry receptor, the implications of these functions in development of ACE2-based therapeutics will also be discussed.
The Impact of COVID-19 on Speech-Language Pathology Practices in Western Kenya
Authors: Gibson Rachael , Rochus David , Musasizi Duncan , Alouch Florence Omolo , Staley Bea
Published: October 2020

This clinical focus article describes speech-language pathology practices of one nongovernment organization in Western Kenya and the professional shifts brought about by COVID-19 in East Africa. This first-person account presents a local overview of the situation, including practical challenges, which are ongoing.
Fast and accurate approximation of the angle-averaged redistribution function for polarized radiation
Authors: Paganini A. , Hashemi B. , Alsina Ballester E. , Belluzzi L.
Published: October 2020

Context.Modeling spectral line profiles taking frequency redistribution effects into account is a notoriously challenging problem from the computational point of view, especially when polarization phenomena (atomic polarization and polarized radiation) are taken into account. Frequency redistribution effects are conveniently described through the redistribution function formalism, and the angle-averaged approximation is often introduced to simplify the problem. Even in this case, the evaluation of the emission coefficient for polarized radiation remains computationally costly, especially when magnetic fields are present or complex atomic models are considered.

Aims.We aim to develop an efficient algorithm to numerically evaluate the angle-averaged redistribution function for polarized radiation.

Methods.The proposed approach is based on a low-rank approximation via trivariate polynomials whose univariate components are represented in the Chebyshev basis.

Results.The resulting algorithm is significantly faster than standard quadrature-based schemes for any target accuracy in the range [10−6, 10−2].
Basic physical and mechanical properties of cement composites after temperature exposure
Authors: Konakova Dana , Vejmelkova Eva , Scheinherrova Lenka , Keppert Martin , Cheng An , Cerny Robert
Published: October 2020

Basic physical and mechanical properties of several cement composites are determined as functions of thermal load and the results are compared with reference materials. Bulk density, matrix density, and open porosity are measured using the water vacuum saturation method. Compressive and bending strengths are determined according to the European standard. High-temperature coefficient of thermal expansion is obtained using a comparative measurement. Experimental results show that composites based on Portland cement do not resist high temperatures well. Their applicability is limited to 400 °C, due to the damage caused by hydrates decomposition. On the other hand, composites based on calcium aluminate cement exhibit a better thermal stability and retain residual strength even after being exposed to 1000 °C.
The impact of the curing process on the efflorescence and mechanical properties of basalt fibre reinforced fly ash-based geopolymer composites
Authors: Korniejenko Kinga , Mierzwiński Dariusz , Szabó Roland , Papné Halyag Nóra , Louda Petr , Thorhallsson Eythor Rafn , Mucsi Gábor
Published: October 2020

Efflorescence is one of the limitations of the widespread use of geopolymers. This problem is caused by excess unreacted sodium oxide remaining inside materials. Unreacted sodium oxide creates white efflorescence on the surface of the produced material in the form of sodium carbonate heptahydrate Na2CO3∙ 7H2O. It decreases not only the aesthetic value of the final products, but also the mechanical properties of the material. The aim of this article is to analyse the influence of the curing method on the appearance of efflorescence on geopolymer composites reinforced by short basalt, especially on mechanical properties. Class F fly ash from the ‘Skawina’ coal-fired power plant (located in Skawina, Lesser Poland, Poland) was used as raw material for the geopolymerization process. The article compares two methods of curing: typical laboratory conditions (in the air) and samples submerged in water. Three series of fly ash-based geopolymer were cast: basalt fibres were added as 1% and 2% by weight of fly ash and one control series without any fibres. The investigation was performed using visual analysis, including microstructure investigation, and the testing of mechanical properties (compressive strength at ambient temperature) after 28 days.
Towards the sustainable use of granite powder waste for manufacturing of cementitious composites
Authors: Chajec Adrian
Published: October 2020

The article is devoted to the description of the current state of knowledge about the possibilities of sustainable use of granite powder waste for manufacturing of cementitious composites. Granite powder waste is waste material resulting from the treatment of granite stone. In dry form, it is harmful to the environment and causes its degradation. One way to reduce its harmful effects is to use it for the sustainable production of cement composites and to use it as supplementary cementitious material (SCM). The results of researches carried out so far related to the impact of granite powder waste on the properties of fresh and hardened cementitious mixes are described. These results were compared and research gaps related to these studies were indicated. In summary, conclusions have been pointed out that indicate that granite powder waste can potentially be used as supplementary cementitious material, but comprehensive, comprehensive research related to this additive should also be carried out.
Basic Physical, Mechanical, Thermal and Hygric Properties of Concrete with Coarse Aggregates Fabricated from Recycled Concrete Pavements
Authors: Fiala Lukáš , Doleželová Magdaléna , Kočí Václav , Lin Wei-Ting , Hager Izabela
Published: October 2020

Concrete production unfavourably affects the environment due to high energy demands of cement production and consumption of limited natural resources. Therefore, waste utilization in fabrication of cementitious material is beneficial and legitimate. Significant reduction of environmental impact can be secured by utilization of various types of wastes or byproducts used for a partial substitution of cement binder or aggregates. However, the use of waste materials usually leads to deterioration of material properties of the designed composites. Therefore, it is very important to thoroughly investigate important materials properties to verify performance and practical usability of the newly designed materials. In this paper, three types of concrete mixes were designed. The reference concrete involved fine and coarse natural riverbed aggregates and two other mixes were designed using both, natural and recycled aggregates represented by crushed concrete paving cobbles. Concretes were tested in terms of basic physical properties (bulk density), mechanical properties (compressive strength), thermal properties (thermal conductivity, specific heat capacity, thermal diffusivity), and hygric properties (water vapour diffusion resistance factor, water vapour sorption at 97% RH, water absorption coefficient, moisture diffusivity) and experimentally determined data were compared and discussed. It was observed that materials properties of concretes with recycled aggregates are comparable with those of the reference concrete which is a promising fact from the environmental point of view.
The Use of Geopolymers for the Disposal of Asbestos-containing Materials
Authors: Łach Michał , Lichocka Katarzyna , Hebdowska-Krupa Maria , Lin Wei-Ting , Korniejenko Kinga
Published: October 2020

Asbestos is widely known as a hazardous material and can contribute to many diseases. Its removal and neutralization are complicated, it requires proper preparation and the use of appropriate technology. Immobilization of asbestos materials in geopolymers seems to be one of the alternatives to its storage in landfills. However, this requires several studies confirming the possibility of asbestos immobilization in geopolymers. Also, asbestos dust contains silicon and aluminum, which may prove useful in the production of geopolymers. The paper presents research results regarding the possibility of using geopolymers based on fly ashes for neutralizing asbestos. An up-to-date literature review on the technology of managing asbestos-containing products is presented. As a result of the research, partial usefulness of geopolymerization technology for binding and neutralizing waste with asbestos was found. The research was carried out using waste asbestos-cement composites. Mixtures based on geopolymers were made in which ground asbestos material was introduced in an amount of 30, 50 and 70% by weight. Compressive strength tests have shown that geopolymers with the addition of asbestos have compressive strength: over 34 MPa for a composition containing 30% of asbestos material and about 14 MPa for a composition containing 70% of asbestos material. SEM observations have shown that asbestos fibers do not dissolve in the geopolymer production process and they can still be a threat if the geopolymer matrix is damaged.
Microstructure of biopolymer-modified aerial lime mortars
Authors: Žižlavský Tomáš , Vyšvařil Martin , Bayer Patrik , Rovnaníková Pavla
Published: October 2020

Cellulose-based viscosity-modifying admixtures are used on daily basis in a wide range of building materials, dominantly in pre-mixed mortar systems. Lately, alternative admixtures such as different “gums” have emerged. In building materials, the gums have similar viscosity-enhancingeffects as cellulose ethers with different efficiency. Various ways of production, as well as diverse working mechanisms of the biopolymers are to be considered while choosing the most suitable admixture for the intended use. Influence of alternative admixtures in several doses on the microstructure of lime mortars was studied in this paper. Mortars were prepared with the same workability and the air content in fresh mortar was determined, for it can have notable impact on microstructure of hardened mortar. Hydroxypropyl derivative of chitosan showed air entraining ability, while the carboxymethyl derivative reported slight decrease in amount of air entrained into the mixture. In the case of diutan gum, the most water-demanding admixture, the percentage of entrained air dropped with growing dose. Admixture addition increased the volume of pores in diameter lower than 0.1 μm, and in region of pores around 10 μm. Only the diutan gum affected the distribution of capillary pores, which are typical for lime mortars. Hygric properties were in correlation with air content values.
Effect of the amount of river sediment on the basic properties of cement mortars
Authors: Zdeb Tomasz , Tracz Tomasz , Adamczyk Marcin
Published: October 2020

According to current legal regulations, bottom sediment in watercourses containing heavy metals are considered dangerous to the environment and should be properly managed after extraction. Due to the well-known excellent ability of the products of cement hydration to immobilize heavy metals, the possibility of utilizing this type of waste products in cement composites was preliminary tested. For this purpose, basic research was carried out on the technological and mechanical characteristics of binders containing sediment from one of the rivers located in Lesser Poland. Standard mortars made of Portland cement CEM I and river sediment dried at 105°C were used for the tests. This supplement replaced cement in the amount of 10%, 20%, 30% and 40% by weight. The technological properties such as: water demand, setting time, consistency and mechanical properties were verified. Compressive and tensile strength at bending of hardened mortars were tested at different curing periods, i.e. after 14, 28 and 90 days. The obtained test results confirm that the fraction of river sediment in the binder in the amount of 10% generally does not adversely affect the properties of mortars, however, its greater amount is reflected in changes in the technological features and in a clear reduction of mechanical properties of the tested mortars.
The influence of superplasticizer and shrinkage reducing admixture type on air-content and related properties of HPSCC
Authors: Łaźniewska-Piekarczyk Beata
Published: October 2020

Theoretically, high-performance concrete with w/c ratio about 0.30 and w/b about 0.28 should have low porosity, low water permeability and high strength. The purpose of this study was to examine the influence of the superplasticizers( with and without air-entraining effect) and shrinkage reducing admixture based on a high molecular weight basis alcohol amount on the air-content, compressive strength, shrink and resistance to water penetration of high-performance self-compacting concrete (HPSCC). The test results have shown that despite the low water content, concrete modified with inadequately selected SP and high amount of SRA has a high porosity and low strength and water permeability. The types of superplasticizers and amount of SRA are significant due to porosity parameters, compressive strength and water-permeability of HPSCC. The water permeability and compressive strength of HPSCC depending on the effects of amount of SRA admixtures on the volume of pores in HPSCC. Moreover, shrinkage of incidental air-entrained concrete, despite its lower endurance, after 28 days of hardening it is smaller than non-aerated concrete.
Considerations on design, development and testing of Electrical Machines for automotive HVAC
Authors: Martis Radu , Pop-Piglesan Florin , Cosman Sorin , Martis Claudia
Published: October 2020

HVAC represents one of the highest energy consumer in a vehicle and for full electric vehicles, the design of HVAC and the dimensioning of its driving system is of utmost importance in order to avoid the limitation of driving range. Due to its advantages, especially when it comes to power density, PMSM is one of the most used electrical machines for a wide range of automotive applications, including HVAC systems. The paper presents the generation of the requirements, design, analysis and HiL testing of a PMSM for HVAC applications. The challenge is to develop a machine answering to the requirements for an electric vehicle HVAC at low- voltage. An experimental model of the machine was tested using a test- bench, based on HiL techniques.
Mechanical behaviour and permeability of geopolymer mortars
Authors: Sitarz Mateusz , Choińska Marta , Hager Izabela , Khelidj Abdelhafid
Published: October 2020

Geopolymers may be considered as an alternative materials to Portland cement ones, providing an opportunity to exploit industrial wastes or co-products with promising short and long-term performances in the construction field, f.ex. for reparation issues. However, these materials are porous and consequently their durability depends on the risk of intrusion of aggressive agents. In order to assess their durability, we propose to investigate in this study gas permeability of sound and mechanically loaded specimens. Loading is performed using a splitting tensile test driven by a crack opening displacement up to a level of 50 microns. Tests are performed on four types of blended fly-ash (FA) and ground granulated blast furnace slag (GGBFS) geopolymer mortars, containing four different levels of GGGBF slag in the binder: 0%, 10%, 30% and 50% wt. Results show a positive effect of blending with slag in terms of modulus of elasticity and tensile and compressive strength, as well as the permeability. However, permeability recovery after cracking is the lowest when blending is the highest.
The magnetic circuit dynamics of a magnetorheological valve with a permanent magnet
Authors: Kubík Michal , Jeniš Filip , Hašlík Igor
Published: October 2020

The magnetorheological (MR) damper uses magnetorheological fluid which, when subjected to magnetic stimuli, generates an increase of damping forces. A significant problem of these dampers is their poor failsafe ability due to power supply interruption. In the case of faults, the damper remains in a low damping state, which is dangerous. This problem can be solved by accommodating a permanent magnet in the magnetic circuit of the damper. However, the magnetic circuit dynamic of this type of damper has rarely been studied. The main aim of this paper is to introduce the magnetic circuit dynamics of the magnetorheological damper/control valve with a permanent magnet. Firstly, the design of the magnetorheological valve with NdFe42 permanent magnet in the magnetic circuit is introduced. The response time of the magnetic field on the unit step of the control signal was calculated by transient magnetic simulation in Ansys Electronics software. The response time of the magnetic field was simulated in the range of 1.2 to 5 ms depending on the electric current magnitude and orientation. The presented MR damper was manufactured and tested. The experiments prove that the permanent magnet significantly affects the dynamics of the magnetic circuit.
Conséquences de l’oxydation sur l’absorption d’eau dans les matrices PEEK et PEI
Authors: Courvoisier Emilie , Bicaba Yoann , Colin Xavier
Published: October 2020

Les conséquences du vieillissement thermique sur les propriétés de transport d’eau (i.e. la solubilité et la diffusivité) dans les matrices PEEK et PEI ont été étudiées dans cinq atmosphères humides : 10, 30, 50, 70 et 90 % HR, en immersion dans l’eau distillée (correspondant en théorie à 100 % HR) et à trois températures : 30, 50 et 70 °C. Les produits d’oxydation ont été caractérisés par spectrophotométrie IRTF et les propriétés de transport d’eau ont été déterminées par des essais de sorption d’eau en enceinte climatique ou en immersion dans l’eau distillée. Les hydroxyles, qui sont de loin les produits d’oxydation les plus polaires, augmentent sensiblement la concentration d’eau à l’équilibre, mais ralentissent aussi la diffusion de l’eau dans ces deux matériaux. En revanche, la perméabilité à l’eau (qui est le produit de ces deux grandeurs) ne varie pratiquement pas pendant le vieillissement thermique. Des relations entre la structure chimique et les propriétés de transport d’eau ont été établies pour permettre le calcul des évolutions des gradients de concentration d’eau dans ces deux matériaux dans leurs conditions habituelles de fonctionnement.
Synthesis of gem-Difluoroalkenes via a Sequence of Hydroboration and 1,2-Elimination of α,β-Unsaturated Carbonyls
Authors: Jiang Gaoxi , An Shiyun , Zhang Jinlong
Published: October 2020

We reported a simple protocol for the synthesis of gem-difluoroalkenes via a reaction sequence of hydroboration and 1,2-elimination of α,β-unsaturated carbonyl substrates under mild conditions. Two steps of this method could be executed in one pot. The β-CF2H- and β-CFH2-α,β-unsaturated carbonyls can be obtained smoothly from the α,β-unsaturated gem-difluoroamide with NaH as the base and via a boration–1,2-elimination sequence.
A Growing Dilemma: Antenatal Corticosteroids and Long-Term Consequences
Authors: Asztalos Elizabeth V. , Murphy Kellie E. , Matthews Stephen G.
Published: October 2020

Objective A single course of synthetic antenatal corticosteroids is standard care for women considered to be at risk for preterm birth before 34 weeks of gestation. While the intended target is the fetal lung, the fetal brain contains remarkably high levels of glucocorticoid receptors in structures critical in the regulation of behavior and endocrine function. Negative programming signals may occur which can lead to permanent maladaptive changes and predispose the infant/child to an increased risk in physical, mental, and developmental disorders.

Methods Framed around these areas of concerns for physical, mental, and developmental disorders, this narrative review drew on studies (animal and clinical), evaluating the long-term effects of antenatal corticosteroids to present the case that a more targeted approach to the use of antenatal corticosteroids for the betterment of the fetus urgently needed.

Results Studies raised concerns about the potential negative long-term consequences, especially for the exposed fetus who was born beyond the period of the greatest benefit from antenatal corticosteroids. The long-term consequences are more subtle in nature and usually manifest later in life, often beyond the scope of most clinical trials.

Conclusion Continued research is needed to identify sufficient safety data, both short term and long term. Caution in the use of antenatal corticosteroids should be exercised while additional work is undertaken to optimize dosing strategies and better identify women at risk of preterm birth prior to administration of antenatal corticosteroids.

Key Points
The role of business models in firm internationalization: An exploration of European electricity firms in the context of the energy transition
Authors: Bohnsack René , Ciulli Francesca , Kolk Ans
Published: October 2020

This article ties in directly with recently intensified interest in business models in international business (IB), using the energy transition as empirical context to explore their relevance in firm internationalization. The global energy transition presents a challenge for almost all industries, but some face specific difficulties particularly important from an IB perspective. We study a set of European firms that used to operate in a highly regulated context with (partial) state ownership, until government-directed market liberalization started to allow further competition and internationalization. Existing firms were prompted to adapt their business models to these changes, with new ventures entering the market to reap opportunities with novel energy-related technologies and business models. Linking insights from strategic management to the IB literature, we conceptualize business model-related specific advantages (BMSAs), and explore the role of BMSAs in the internationalization of the firms in our sample. We also uncover barriers to BMSA recombination in (potential) host countries, consider BMSA location-boundedness, and discuss implications for firms’ international expansion by presenting a new framework. Consequences for the energy transition and the actors already involved and (in)directly confronted with it are explicated, while outlining promising areas for further research, building on the insights and limitations of our study.
A microfluidic flow meter with micromachined thermal sensing elements
Authors: Zhao Pu-Jun , Gan Rong , Huang Liji
Published: October 2020

The design, fabrication, operation, calibration, and performance of a microfluidic flow meter utilizing a micromachined (MEMS) thermal time-of-flight sensing chip are presented. The MEMS sensing chip integrates multiple sensing elements (thermistors) on a silicon substrate. This sensing chip works on the principle of thermal excitation with a modulated power source from the microheater while the responses of the sensing elements at both upstream and downstream of the modulated thermal source are processed for both the time differences and the amplitudes of the heat transfer in the microfluidic flow. Unlike most of the current flow meter products based on the thermal sensing principle that only offer the calorimetric mass flow rates, this flow meter can measure not only the mass flow rate but also the flow media properties. Experimental results for water and isopropyl alcohol are discussed, which demonstrate the capability and performance of the novel microfluidic flow meter.
Asymptotic behavior for the 1D stochastic Landau–Lifshitz–Bloch equation
Authors: Qiu Zhaoyang , Tang Yanbin , Wang Huaqiao
Published: October 2020

The stochastic Landau–Lifshitz–Bloch equation describes the phase spins in a ferromagnetic material and has a significant role in simulating heat-assisted magnetic recording. In this paper, we consider the deviation of the solution to the 1D stochastic Landau–Lifshitz–Bloch equation, that is, we give the asymptotic behavior of the trajectory uε−u0ελ(ε) as ɛ → 0+, for λ(ε)=1ε and 1, respectively. In other words, the large deviation principle and the central limit theorem are established, respectively.
Transverse beam envelope structures in strongly coupled stimulated Brillouin scattering
Authors: Schmitz H. , Trines R. , Bingham R.
Published: October 2020

We use a newly developed code to investigate cross beam energy transfer via Brillouin scattering in the strong coupling limit. The code couples a single fluid model of the plasma to the complete set of Maxwell's equations. The code can describe beam interaction at arbitrary angles. We observe that the formation of a transverse structure on both beams is caused when the pump beam is fully depleted within the width of the beam. We present a simplified envelope model that confirms the results of the simulation. This transverse beam structure formation has implications for short pulse amplification. The results may also be relevant for fast ignition schemes for inertial confinement fusion.
Alloy segregation at stacking faults in zincblende GaN heterostructures
Authors: Ding B. , Frentrup M. , Fairclough S. M. , Kappers M. J. , Jain M. , Kovács A. , Wallis D. J. , Oliver R. A.
Published: October 2020

Current cubic zincblende III-Nitride epilayers grown on 3C-SiC/Si(001) substrates by metal-organic vapor-phase epitaxy contain a high density of stacking faults lying on the {111} planes. A combination of high-resolution scanning transmission electron microscopy and energy dispersive x-ray spectrometry is used to investigate the effects of alloy segregation around stacking faults in a zincblende III-nitride light-emitting structure, incorporating InGaN quantum wells and an AlGaN electron blocking layer. It is found that in the vicinity of the stacking faults, the indium and aluminum contents were a factor of 2.3 ± 1.3 and 1.9 ± 0.5 higher, respectively, than that in the surrounding material. Indium and aluminum are also observed to segregate differently in relation to stacking faults with indium segregating adjacent to the stacking fault while aluminum segregates directly on the stacking fault.
Excitation induced enhancement of spectral response and energy transfer mechanisms in Fe/Sm modified ZnO phosphors
Authors: Kaur Puneet , Kaur Simranpreet , Kriti  , Arora Deepawali , Vashishtha Pargam , Gupta Govind , Chen Chi-Liang , Dong Chung-Li , Asokan Kandasami , Singh Davinder Paul
Published: October 2020

The present study aims to analyze the tunability of photonic emissions as a function of excitation wavelengths in Fe/Sm co-doped ZnO phosphors. We have investigated the up-conversion (UC) and down-conversion (DC) luminescences in detail along with possible channels for energy transfer and their local electronic structures. These phosphors are polycrystalline with a hexagonal wurtzite structure, and the co-doping of Fe/Sm ions leads the 3D-pyramid like morphology of the ZnO to transform in flower-shaped nanorods. Further, from the UV–Vis spectra, it is found that bandgap contracts due to the formation of defects. The DC emission spectra (λex = 325 nm) show an enhancement of polychromatic emission as a function of the Sm concentration and tune from orange to red along with the transition from the warm to cool region in the Commission International de l'Eclairage 1931 XY spectral chromaticity coordinates. X-ray absorption spectra confirm the presence of Fe2+/Fe3+ ions and Sm3+ ions. Using the decay kinetics and transfer efficiencies, the energy transfer between the host defect levels and dopant ions is explained with the help of the energy level diagram. The UC emission spectra (λex = 980 nm) exhibit monochromatic red emission along with a strong near-infrared emission lying in the cool region with 100% color purity. These phosphors are expected to find applications in solid-state lighting applications, optoelectronics, and biomedical engineering, etc.
Measurements of enhanced performance in an indirect drive inertial confinement fusion experiment when reducing the contact area of the capsule support
Authors: Ralph J. E. , Döppner T. , Hinkel D. E. , Hurricane O. , Landen O. , Smalyuk V. , Weber C. R. , Bigelow J. , Bachmann B. , Casey D. T. , Clark D. , Diaz S. , Felker S. , Hammel B. A. , Khan S. F. , Nikroo A. , Pak A. , Patel P. K. , Callahan D. A. , Sater J. , Springer P. , Stadermann M. , Walters C. , Havre M. , Volegov P. L.
Published: October 2020

Experimental results from indirectly driven inertial confinement fusion experiments testing the performance gained from using an alternate capsule tent support are reported. The polar tent describes an alternate geometry for the thin membrane used to support the Deuterium–Tritium (DT) filled capsule. Here, the contact area is reduced by 23 times by locating the tent support close to the poles of the capsule. The polar tent experiments are repeats of previous 3 shock 1.63 MJ, 400 TW high foot experiments and use a 165 μm thick silicon doped carbon hydrogen plastic (CH) shell. Using the polar tent support, we report a DT neutron yield of 1.07 ×1016, 76% higher than the expected YDT∝V7.7 scaling. This is, at the time of writing, the highest neutron yield to date from a CH shell implosion. Furthermore, we find that the inferred pressure when using the polar tent is significantly above the model based on analytic scaling even when accounting for tent effects. Analysis of x-ray and neutron images shows the reduction of lobes produced by nominal tent features. The reduction of these features in the polar tent experiments leads to decreased low mode (P2 and P4) asymmetry compared to the nominal tent results.
Extended full-MHD simulation of non-linear instabilities in tokamak plasmas
Authors: Pamela S. J. P. , Bhole A. , Huijsmans G. T. A. , Nkonga B. , Hoelzl M. , Krebs I. , Strumberger E. ,   JET Contributors
Published: October 2020

Non-linear magnetohydrodynamic (MHD) simulations play an essential role in active research and understanding of tokamak plasmas for the realization of a fusion power plant. The development of MHD codes such as JOREK is a key aspect of this research effort. In this paper, we present an operational version of the full-MHD model implemented in JOREK, a significant advancement from the reduced-MHD model used for previous studies, where assumptions were made on the perpendicular dynamics and the toroidal magnetic field. The final model is presented in detail, and benchmarks are performed using both linear and non-linear simulations, including comparisons between the new full-MHD model of JOREK and the previously extensively studied reduced-MHD model, as well as results from the linear full-MHD code CASTOR3D. For the cases presented, this new JOREK full-MHD model is numerically and physically reliable, even without the use of numerical stabilization methods. Non-linear modeling results of typical tokamak instabilities are presented, including disruption and edge-localized-mode physics, most relevant to current open issues concerning future tokamaks such as ITER and DEMO.
A numerical study on the interaction between two cross-flow turbines in tandem configuration to support a simplified turbine model approach
Authors: Tremblay Olivier G. , Dumas Guy
Published: October 2020

In the planning of hydrokinetic turbine array deployment and for the performance prediction of its constituent turbines, the use of simplified turbine models is essential to alleviate the computational costs. The Effective Performance Turbine Model (EPTM) introduced in 2018 is a promising tool for that purpose, allowing array analysis and optimization. Its performance predictions scale with a local flow velocity characterization, which ensures to take into account inherently blockage effects and mean, local flow conditions. However, the characteristics of the local flow within an array also include different types of perturbation such as shear, large-scale temporal fluctuations, and turbulence. To ensure that the model is still reliable in those conditions, this paper presents a validation of the EPTM through the analysis of a large-scale tandem turbine configuration. In fact, three unsteady-Reynolds-averaged-Navier–Stokes simulations of a cross-flow turbine tandem configuration with a longitudinal spacing of six diameters have been conducted in this study, in addition to a simulation of a single turbine with turbulent ambient conditions. This set of simulations allows us to study independently the different types of perturbations associated with array deployment. Whereas the slow-varying large-scale upstream velocity fluctuations do not seem to affect significantly the turbine operation, the upstream non-uniform velocity distribution affects appreciably the extracted power. We find also that the value of the effective power coefficient associated with the EPTM needs to be adapted to the array simulation. Compared to the case of a single turbine in a uniform flow with a low turbulence level, we show that a smaller effective power coefficient value must be used in array simulations. An important result is that the different types of perturbations are found to yield similar effective performance coefficients, which suggests that the same set of values can be used throughout the array. With the appropriate set of values, we show that the EPTM succeeds to predict accurate downstream turbine performance.
Aeroacoustic design and broadband noise predictions of a fan stage with serrated outlet guide vanes
Authors: Polacsek C. , Cader A. , Buszyk M. , Barrier R. , Gea-Aguilera F. , Posson H.
Published: October 2020

This work, realized in the framework of the European project TurboNoiseBB, presents an advanced aeroacoustic design methodology of Outlet Guide Vanes (OGVs) with leading edge serrations, including details on their broadband noise and aerodynamic performance. The serrated OGV corresponds to a modified stator from an aeroengine fan stage tested at the AneCom AeroTest’s facility (Germany). Sinusoidal leading edge patterns with varying amplitude and wavelength along the span are designed in collaboration with Safran Aircraft Engines. Serrations are adjusted to account for the turbulence characteristics provided by Reynolds-Averaged Navier–Stokes (RANS) calculations. Optimal parameters are found using simple design rules discussed in this paper. Down selection of serrated OGV designs (patent pending) is conducted through a RANS control of aerodynamic performances and in accordance with industrial specifications, ensuring acceptable penalties on the loss coefficient and isentropic efficiency. Broadband noise simulations are performed using a computational aeroacoustic (CAA) code that solves the linearized Euler equations with a synthetic turbulence model. Additionally, the acoustic response of the serrated leading edge airfoils is also estimated using the most relevant analytical formulation in the literature, based on the Wiener–Hopf technique. Numerical predictions at approach conditions are compared to available experimental measurements (on the untreated baseline case) and analytical Amiet-based and Wiener–Hopf solutions, showing satisfactory agreement in the sound power spectrum in the bypass duct. Finally, the acoustic performances estimated at the design stage are numerically assessed by both the CAA and Wiener–Hopf methods, providing around 2.5 dB and 3.5 dB reduction in the overall power level, respectively.
On the bremsstrahlung background of the neutron yield diagnostic in deuterium-filled capsule implosions driven by Z-pinch dynamic hohlraums on an 8-MA pulsed power facility
Authors: Yi Qiang , Guo Hongsheng , Hu Qingyuan , Meng Shijian , Yang Jianlun , Ning Jiamin , Huang Zhanchang , Yang Ruihua , Yan Xiaosong , Lu Jian , Ye Fan , Jiang Shuqing , Liang Chuan , Li Mingjia , Wang Wenchuan , Chen Faxin , Xu Zeping , Xu Rongkun , Li Zhenghong
Published: October 2020

The thermonuclear yield from deuterium-filled capsule implosions driven by Z-pinch dynamic hohlraums on an 8-MA pulsed power facility is diagnosed by Ag activation and neutron time-of-flight (nTOF). However, both detector systems suffer from an excessive bremsstrahlung background. Tests on the Ag activation system suggest that the facility may produce such an intense super-MeV x-ray background that the resulting photonuclear-excitation reactions can overwhelm the potential neutron signal. In the nTOF detectors, the high bremsstrahlung background generates such an excessive afterglow in the scintillator that confirming any thermonuclear yield may require a liquid scintillator with a much lower afterglow together with a gated photomultiplier.
Two-dimensional electronic Stark spectroscopy of a photosynthetic dimer
Authors: Nguyen Hoang H. , Loukianov Anton D. , Ogilvie Jennifer P. , Abramavicius Darius
Published: October 2020

Stark spectroscopy, which measures changes in the linear absorption of a sample in the presence of an external DC electric field, is a powerful experimental tool for probing the existence of charge-transfer (CT) states in photosynthetic systems. CT states often have small transition dipole moments, making them insensitive to other spectroscopic methods, but are particularly sensitive to Stark spectroscopy due to their large permanent dipole moment. In a previous study, we demonstrated a new experimental method, two-dimensional electronic Stark spectroscopy (2DESS), which combines two-dimensional electronic spectroscopy (2DES) and Stark spectroscopy. In order to understand how the presence of CT states manifest in 2DESS, here, we perform computational modeling and calculations of 2DESS as well as 2DES and Stark spectra, studying a photosynthetic dimer inspired by the photosystem II reaction center. We identify specific cases where qualitatively different sets of system parameters produce similar Stark and 2DES spectra but significantly different 2DESS spectra, showing the potential for 2DESS to aid in identifying CT states and their coupling to excitonic states.