bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactive molecular dynamics simulation of the high-temperature pyrolysis of 2,2′,2′′,4,4′,4′′,6,6′,6′′-nonanitro-1,1′:3′,1′′-terphenyl (NONA)
Authors: Song Liang , Zhao Feng-Qi , Xu Si-Yu , Ju Xue-Hai
Published: February 2020

The bimolecular and fused ring compounds are found in the high-temperature pyrolysis of NONA using ReaxFF molecular dynamics simulations.
Photochemical anti–syn isomerization around the –N–N bond in heterocyclic imines
Authors: Hricovíni Michal , Asher James , Hricovíni Miloš
Published: February 2020

Irradiation with UV light (365 nm) leads to photochemically-induced isomerization from the anti- to the higher-energy syn-form around the –N–N linkage.
ATP-responsive mitochondrial probes for monitoring metabolic processes of glioma stem cells in a 3D model
Authors: Lin Ling , Yi Linglu , Zhao Fanghao , Wu Zengnan , Zheng Yajing , Li Nan , Lin Jin-Ming , Sun Jiashu
Published: February 2020

The metastatic cascade of cancer stem cells (CSCs) is always accompanied by elevated levels of adenosine triphosphate (ATP) as well as the alteration of energy metabolism to support their differentiation and migration.
pH stability and disassembly mechanism of wild-type simian virus 40
Authors: Asor Roi , Khaykelson Daniel , Ben-nun-Shaul Orly , Levi-Kalisman Yael , Oppenheim Ariella , Raviv Uri
Published: February 2020

At high pH, wtSV40 swells, and its minichromosome pokes a hole in the capsid and escapes, following which the capsid disintegrates.
A robust esterified nanofibre electrode for proton exchange membrane fuel cells
Authors: Qi Manman , Hou Ming , Zeng Yachao , Gao Yanyan , Yang Yue , He Liang , Chen Haiping , Zhang Hongjie , Song Wei , Shao Zhigang
Published: February 2020

An esterified nanofibre electrode with enhanced dimensional stability has been proposed for proton exchange membrane fuel cells.
Progress in nickel chalcogenide electrocatalyzed hydrogen evolution reaction
Authors: Anantharaj S. , Kundu Subrata , Noda Suguru
Published: February 2020

Nickel chalcogenides are a special class of electrocatalysts that possess exceptional HER activity and this review gives a comprehensive overview of their recent development.
Enhanced biosensing strategies using electrogenerated chemiluminescence: recent progress and future prospects
Authors: Husain Rashaad A. , Barman Snigdha Roy , Chatterjee Subhodeep , Khan Imran , Lin Zong-Hong
Published: February 2020

An overview of enhancement strategies for highly sensitive ECL-based sensing of bioanalytes enabling early detection of cancer.
A lysosome-targeted near-infrared fluorescent probe for imaging endogenous cysteine (Cys) in living cells
Authors: Cai Songtao , Liu Chang , Jiao Xiaojie , Zhao Liancheng , Zeng Xianshun
Published: February 2020

A lysosome-targeted near-infrared (NIR) fluorescent probeSHCy-Cfor detecting and imaging endogenous Cys in living cells has been developed.
Electrical fatigue behavior of NBT-BT-xKNN ferroelectrics: effect of ferroelectric phase transformations and oxygen vacancies
Authors: Shi Xi , Kumar Nitish , Hoffman Mark
Published: February 2020

The reduction of degradation rate at high cycles indicates the subsequent contribution from micro-scale surface damage, leading to irreversible fatigue.
Modulation of the optoelectronic properties of a donor–acceptor conjugate between a cationic polythiophene and a peptide appended perylene bisimide ampiphile
Authors: Hazra Soumyajit , Shit Arnab , Ghosh Radhakanta , Basu Kingshuk , Banerjee Arindam , Nandi Arun K.
Published: February 2020

The morphology of a cationic polythiophene changes from core–shell to a mixed fibrillar network with black spots, quenching of the PL-intensity and an enhanced photo switching property on addition of peptide appended perylene bisimide.
Color switching in V3O7·H2O films cycled in Li and Na based electrolytes: novel vanadium oxide based electrochromic materials
Authors: Mjejri Issam , Rougier Aline
Published: February 2020

Vanadium oxides exhibiting various V/O stoichiometries are considered as one of the most promising chromogenic materials for energy purposes.
Correction: A facile strategy to realize a single/double photon excitation-dependent photosensitizer for imaging-guided phototherapy against HeLa cancer cells at separate irradiation channels
Authors: Kong Lin , Huang Ze , Zhang Shuai-Shuai , Song Jian , Zhang Yu-Yang , Bai Xiang-Yang , Yang Jia-Xiang , Li Lin
Published: February 2020

Correction for ‘A facile strategy to realize a single/double photon excitation-dependent photosensitizer for imaging-guided phototherapy against HeLa cancer cells at separate irradiation channels’ by Lin Kong et al., Chem. Commun., 2020, 56, 571–574.
Equatorial coordination optimization for enhanced axiality of mononuclear Dy(iii) single-molecule magnets
Authors: Yu Ke-Xin , Ding You-Song , Zhai Yuan-Qi , Han Tian , Zheng Yan-Zhen
Published: February 2020

The optimization of equatorial sites leads to significant improvement of the magnetic properties of Dy(iii) SMMs.
Brønsted and Lewis acid adducts of triazenes
Authors: Landman Iris R. , Suleymanov Abdusalom A. , Fadaei-Tirani Farzaneh , Scopelliti Rosario , Chadwick F. Mark , Severin Kay
Published: February 2020

Spectroscopy and crystallographic data show that triazenes are protonated at N1 position.
Turning on electrocatalytic oxygen reduction by creating robust Fe–Nx species in hollow carbon frameworks via in situ growth of Fe doped ZIFs on g-C3N4
Authors: Wang Guizhi , Deng Jiang , Yan Tingting , Zhang Jianping , Shi Liyi , Zhang Dengsong
Published: February 2020

Robust Fe–Nx species in hollow carbon frameworks were in situ created to turn on electrocatalytic oxygen reduction.
A comparative study on the mechanical and reactive behavior of three fluorine-containing thermites
Authors: Wu Jiaxiang , Liu Qiang , Feng Bin , Wu Shuangzhang , Zhang Sheng , Gao Zhenru , Yin Qin , Li Yuchun , Xiao Liming , Huang Junyi
Published: February 2020

Solid fluorine-containing thermite with different PTFE content were fabricated by referring to the traditional thermite and adding PTFE as a binder or matrix to investigate the mechanical and reactive behavior of composites.
Efficient synthesis of niobium pentoxide nanowires and application in ethanolysis of furfuryl alcohol
Authors: Zhang Zhenwei , Wang Peng , Wu Zeying , Yue Chuanjun , Wei Xuejiao , Zheng Jiwei , Xiang Mei , Liu Baoliang
Published: February 2020

Nb2O5 nanowires with high specific surface area and crystallinity were prepared by using ammonium oxalate and an acetic acid solvent system.
Theranostic nanoparticles enabling the release of phosphorylated gemcitabine for advanced pancreatic cancer therapy
Authors: Wang Qingbing , Zhu Xingjun , Wu Zhiyuan , Sun Tao , Huang Wei , Wang Zhongmin , Ding Xiaoyi , Jiang Chen , Li Fuyou
Published: February 2020

A lanthanide-based visualizable photothermal controlled drug release nanosystem was developed to overcome the drug resistance of gemcitabine for pancreatic cancer.
Persulfides, at the crossroads between hydrogen sulfide and thiols
Authors: Benchoam Dayana , Cuevasanta Ernesto , Möller Matías N. , Alvarez Beatriz
Published: February 2020

Persulfides (RSSH/RSS−) can be formed in protein and non-protein thiols (RSH) through several different pathways, some of which are dependent on hydrogen sulfide (H2S/HS−). In addition to their roles in biosynthetic processes, persulfides are possible transducers of physiological effects of H2S through the modification of critical cysteines. Persulfides have a very rich biological chemistry that is currently under investigation. They are more nucleophilic and acidic than thiols and, unlike thiols, they can also be electrophilic. They are especially good one-electron reductants. Methods to detect their formation are under continuous development. In this minireview we describe the pathways of formation of persulfides, their biochemical properties and the techniques available for their detection, and we discuss the possible implications of their formation in biological systems.
3-Nitrotyrosine and related derivatives in proteins: precursors, radical intermediates and impact in function
Authors: Campolo Nicolás , Issoglio Federico M. , Estrin Darío A. , Bartesaghi Silvina , Radi Rafael
Published: February 2020

Oxidative post-translational modification of proteins by molecular oxygen (O2)- and nitric oxide (•NO)-derived reactive species is a usual process that occurs in mammalian tissues under both physiological and pathological conditions and can exert either regulatory or cytotoxic effects. Although the side chain of several amino acids is prone to experience oxidative modifications, tyrosine residues are one of the preferred targets of one-electron oxidants, given the ability of their phenolic side chain to undergo reversible one-electron oxidation to the relatively stable tyrosyl radical. Naturally occurring as reversible catalytic intermediates at the active site of a variety of enzymes, tyrosyl radicals can also lead to the formation of several stable oxidative products through radical–radical reactions, as is the case of 3-nitrotyrosine (NO2Tyr). The formation of NO2Tyr mainly occurs through the fast reaction between the tyrosyl radical and nitrogen dioxide (•NO2). One of the key endogenous nitrating agents is peroxynitrite (ONOO−), the product of the reaction of superoxide radical (O2•−) with •NO, but ONOO−-independent mechanisms of nitration have been also disclosed. This chemical modification notably affects the physicochemical properties of tyrosine residues and because of this, it can have a remarkable impact on protein structure and function, both in vitro and in vivo. Although low amounts of NO2Tyr are detected under basal conditions, significantly increased levels are found at pathological states related with an overproduction of reactive species, such as cardiovascular and neurodegenerative diseases, inflammation and aging. While NO2Tyr is a well-established stable oxidative stress biomarker and a good predictor of disease progression, its role as a pathogenic mediator has been laboriously defined for just a small number of nitrated proteins and awaits further studies.
Thermal stability of polyphenylsilsesquioxane‐modified meta‐aramid insulation paper
Authors: Tang Chao , Zheng Wei , Wang Lihan , Xie Jufang
Published: February 2020

The development of new materials for use in advanced distribution transformers is required to improve their heat resistance rating, operational safety, and reliability. The combination of polymer and nanoparticles is the preferred approach to improve the thermal stability of materials. In this study, the thermal stability of laboratory‐prepared meta‐aramid insulation paper modified with polyphenylsilsesquioxane (PPSQ) was evaluated. The results showed that the thermal stability of the modified insulation paper was superior to that of the unmodified paper. Molecular dynamics simulations were used to analyse the internal mechanism of the performance improvement achieved by modification with PPSQ. From a microscopic perspective, the addition of PPSQ provided a relatively larger structural space for the meta‐aramid fibre and increased the free volume of the entire system, which tightened the meta‐aramid fibre molecular chains, increased the density of the structure of the paper, and enhanced the mutual permeability between meta‐aramid fibre chains. Therefore, the stress can be better transmitted, the performance loss such as phase delamination was effectively prevented, and the bonding between the meta‐aramid fibres was strengthened.
Enhanced voltage distribution and breakdown strength performances of oil‐paper composite insulation by adding TiO2 nanoparticles
Authors: Huang Meng , Ying Yupeng , Liu Baixin , Lv Yuzhen , Qi Bo , Li Chengrong
Published: February 2020

Abtsract

Oil–paper composite insulation (OPCI) is used as the main insulation material in the converter transformer. However, the dielectric properties of insulating oil and oil‐impregnated paper are markedly mismatched under direct current (DC) voltage, resulting in an unbalanced distribution of voltage, which is considered to be a major cause of large insulation margin but frequent failures. Therefore, it is necessary to adjust the voltage distribution in OPCI to enhance its breakdown strength. In this work, surface‐treated TiO2 nanoparticles were employed to modify OPCI. The polarisation current tests revealed that by changing the additive amount of nanoparticles, the polarisation intensities of both oil and oil‐impregnated paper could be adjusted. Based on this, a model taking relaxation polarisations into full consideration was established to analyse the voltage distribution in OPCI and predict the optimal concentration. The prepared OPCI with the concentration of 0.02 g/L has desired balanced voltage distribution due to the influence of nanoparticles on interface charge, and therefore high breakdown strengths under both DC voltage and polarity reversal voltage, which can be increased by 22.6% at most. This work puts forward a novel idea to improve insulation property of OPCI and provides a reference for broader application of nanomaterial in power equipment.
Profit‐oriented cooperative caching algorithm for hierarchical content centric networking
Authors: Yang Meiyi , Zhang Mingchuan , Zhu Junlong , Liu Ruoshui , Wu Qingtao , Wassell Ian J.
Published: February 2020

Cooperative caching among nodes is a hot topic in Content Centric Networking (CCN). However, the cooperative caching mechanisms are performed in an arbitrary graph topology, leading to the complex cooperative operation. For this reason, hierarchical CCN has received widespread attention, which provides simple cooperative operation due to the explicit affiliation between nodes. In this study, the authors propose a heuristic cooperative caching algorithm for maximising the average provider earned profit under the two‐level CCN topology. This algorithm divides the cache space of control nodes into two fractions for caching contents which are downloaded from different sources. One fraction caches duplicated contents and the other caches unique contents. The optimal value of the split factor can be obtained by maximising the earned profit. Furthermore, they also propose a replacement policy to support the proposed caching algorithm. Finally, simulation results show that the proposed caching algorithm can perform better than some traditional caching strategies.
Highly sensitive microgrid protection using overcurrent relays with a novel relay characteristic
Authors: Darabi Ahmad , Bagheri Mehdi , B. Gharehpetian Gevork
Published: February 2020

Following the high penetration of synchronous generators (SGs) in the power network, optimal overcurrent coordination improvement under faulty conditions has become a crucial problem. To reduce the overcurrent relay operating time, a new overcurrent relay curve is proposed in this study. Then, the overcurrent coordination problem is overcome by using a robust combinatorial optimisation method. Additionally, SG sizing and location is performed to verify the merits of both the proposed relay curve and the applied optimisation algorithm. The proposed relay curve performance is compared with other non‐standard relays characteristic available in the literature for a standard microgrid. Then, the proposed relay curve is applied to both the 8‐bus transmission and the 33 kV distribution portion of the 30‐bus IEEE standard power test systems. Then, the SG transient stability for different fault locations is analysed. Finally, an accurate comparison between the proposed relay curve and standard/non‐standard curves available in the literature is provided by applying the same optimisation method and network topology. The simulation results confirm the superiority of the proposed relay curve.
Extended high‐gain observer‐based DC‐link voltage regulation in dual‐stage grid‐tied PV system under balanced and unbalanced voltages
Authors: Errouissi Rachid , Al‐Durra Ahmed
Published: February 2020

This study presents the design and experimental validation of feedback control along with a high‐gain observer to regulate the DC‐link voltage in dual‐stage grid‐tied photovoltaic (PV) system. In particular, the composite controller is designed to ensure accurate and fast control of the DC‐link voltage in response to abrupt changes in either the delivered active power or grid voltages. The high‐gain observer is employed to estimate the unknown disturbance, which is then cancelled by the feedback controller to ensure asymptotic regulation. Fast disturbance estimation is required to retain the nominal transient response specified under the feedback controller, which mandates using high‐observer gain. However, high‐observer gain magnifies the effect of the measurement noise, which results in poor steady‐state performances. This problem is addressed here by using a non‐linear gain to allow for on‐line adjustment of the observer gain. Specifically, a large observer gain is used during transients to ensure fast disturbance estimation, while a reduced observer gain is employed in the steady‐state regime to mitigate the effect of the measurement noise. Experimental results demonstrated the ability of the proposed controller to achieve accurate control, good transient response, fast disturbance rejection, and negligible sensitivity to the measurement noise.
GNSS attitude estimation based on adaptive Kalman filtering using phase measurement
Authors: Zhang Siyu , Chang Guobin , Chen Chao , Zhang Laihong , Zhu Ting
Published: February 2020

Attitude estimation using multi‐antenna Global Navigation Satellite System (GNSS) has caught broad attention in recent years. The methods of indirectly calculating attitude parameters based on baseline vectors have been widely used. However, the accuracy of such methods needs to be further improved. An algorithm of directly estimating attitude parameters based on adaptive Kalman filtering (AKF) is proposed. The high‐precision phase measurements are used and the system noise covariance matrix corresponding to Euler angles and angle rates is adaptively adjusted according to the maximum a posteriori estimation principle. To decrease the linearisation errors and speed the filtering convergence, a switching strategy is implemented. Namely, when the number of fixed ambiguities is equal to or more than three, the authors deem that the attitude estimate is sufficiently accurate, hence the initial state vector is constructed to start filtering. Otherwise, the attitude parameters are indirectly obtained. The static and simulation experiments are carried out. A comparative study is implemented with the two methods of indirectly calculating attitude parameters. The static and simulation results demonstrate that the proposed method has a competent performance in both accuracy and fixing success rate. The simulation results also show that the adaptability of the AKF method is nice.
Emitter signals modulation recognition based on discriminative projection and collaborative representation
Authors: Li Dongjin , Yang Ruijuan , Dong Ruijie , Zuo Jiajun
Published: February 2020

To enhance the modulation recognition performance of emitter signals under low signal‐to‐noise ratio (SNR), a recognition system based on secondary time–frequency distribution, discriminative projection, and collaborative representation is proposed. Firstly, a novel time–frequency processing method, including sparse‐domain noise reduction and secondary feature extraction, is proposed to reduce noise interference and information redundancy in time–frequency images. In this way, secondary time–frequency distribution with high stability and detailed representation is obtained. Then, the classifier based on discriminative projection and collaborative representation was designed to enhance the ability of low‐dimensional representation and between‐class discrimination, which optimised using the mini‐batch random gradient descent method. As shown in the simulation, the overall average recognition success rate of this system aiming at eight types of emitter signals reaches 95.6% at the SNR of −8 dB. Results of simulation and analysis indicate the superiority of the proposed classification system in terms of robustness, timeliness, and adaptability.
Pull‐in analysis of microbeam laminated with LASMP
Authors: Guo Jun , Yang Yunze , Zhai Haorui
Published: February 2020

This work focuses on the pull‐in phenomena of electrically actuated size‐dependent microbeam laminated with the light‐activated shape memory polymer, which can realise the Young's modulus variation under the light exposure. Based on the modified couple stress theory, a size‐dependent microbeam model is developed. The dynamic governing equation of the microbeam is derived according to the Hamilton principle and solved by the Galerkin method and Runge–Kutta method numerically. The reliability and accuracy of the present method are validated experimentally. The static and dynamic pull‐in behaviours of the microbeam are studied when the microbeam is under a purely direct current voltage and alternating current voltage, respectively. Influences of the size effect and dynamic Young's modulus on pull‐in behaviour of the microbeam are discussed comprehensively. This research may be helpful and useful in electrostatically actuated microstructure applications and provide a theoretical foundation for designers and engineers.
SNe Ia from double detonations: Impact of core-shell mixing on the carbon ignition mechanism
Authors: Gronow Sabrina , Collins Christine , Ohlmann Sebastian T. , Pakmor Rüdiger , Kromer Markus , Seitenzahl Ivo R. , Sim Stuart A. , Röpke Friedrich K.
Published: February 2020

Sub-Chandrasekhar mass white dwarfs accreting a helium shell on a carbon-oxygen core are potential progenitors of normal Type Ia supernovae. This work focuses on the details of the onset of the carbon detonation in the double detonation sub-Chandrasekhar model. In order to simulate the influence of core-shell mixing on the carbon ignition mechanism, the helium shell and its detonation are followed with an increased resolution compared to the rest of the star treating the propagation of the detonation wave more accurately. This significantly improves the predictions of the nucleosynthetic yields from the helium burning. The simulations were carried out with the AREPO code. A carbon-oxygen core with a helium shell was set up in one dimension and mapped to three dimensions. We ensured the stability of the white dwarf with a relaxation step before the hydrodynamic detonation simulation started. Synthetic observables were calculated with the radiative transfer code ARTIS. An ignition mechanism of the carbon detonation was observed, which received little attention before. In this “scissors mechanism”, the impact the helium detonation wave has on unburnt material when converging opposite to its ignition spot is strong enough to ignite a carbon detonation. This is possible in a carbon enriched transition region between the core and shell. The detonation mechanism is found to be sensitive to details of the core-shell transition and our models illustrate the need to consider core-shell mixing taking place during the accretion process. Even though the detonation ignition mechanism differs form the converging shock mechanism, the differences in the synthetic observables are not significant. Though they do not fit observations better than previous simulations, they illustrate the need for multi-dimensional simulations.
Proton acceleration in pulsar magnetospheres
Authors: Guépin Claire , Cerutti Benoît , Kotera Kumiko
Published: February 2020

Pulsars have been identified as good candidates for the acceleration of cosmic rays, up to ultra-high energies. However, a precise description of the acceleration processes at play is still to be established. Using 2D particle-in-cell simulations, we study proton acceleration in axisymmetric pulsar magnetospheres. Protons and electrons are extracted from the neutron star surface by the strong electric field induced by the rotation of the star, and electrons and positrons are produced in the magnetosphere through pair production process. As pair production has a crucial impact on electromagnetic fields, on gaps and thus on particle acceleration, we study its influence on the maximum energy and luminosity of protons escaping the magnetosphere. Protons are accelerated and escape in all our simulations. However, the acceleration sites are different for the protons and the pairs. As shown in previous studies, pairs are accelerated to their highest energies at the Y-point and in the equatorial current sheet, where magnetic reconnection plays an important role. In contrast, protons gain most of their kinetic energy below the light-cylinder radius within the separatrix current layers, but they are not confined within the equatorial current sheet. Their maximum Lorentz factors can reach 15% to 75% of the maximum Lorentz factor obtained by acceleration through the full vacuum potential drop from pole to equator, and increase with decreasing pair production. Their luminosity can reach 0.2% to 4% of the theoretical spin down luminosity of an aligned pulsar, and the minimum luminosity is obtained at the transition between the force-free and electrosphere regimes. These estimates support that millisecond pulsars could accelerate cosmic rays up to PeV energies and that new born millisecond pulsars could accelerate cosmic rays up to ultra-high energies.
The origin of tail-like structures around protoplanetary disks
Authors: Vorobyov Eduard I. , Skliarevskii Alexandr M. , Elbakyan Vardan G. , Takami Michihiro , Liu Hauyu Baobab , Liu Sheng-Yuan , Akiyama Eiji
Published: February 2020

Aims. We study the origin of tail-like structures recently detected around the disk of SU Aurigae and several FU Orionis-type stars.

Methods. Dynamic protostellar disks featuring ejections of gaseous clumps and quiescent protoplanetary disks experiencing a close encounter with an intruder star were modeled using the numerical hydrodynamics code FEOSAD. Both the gas and dust dynamics were taken into account, including dust growth and mutual friction between the gas and dust components. Only plane-of-the-disk encounters were considered.

Results. Ejected clumps produce a unique type of tail that is characterized by a bow-shock shape. Such tails originate from the supersonic motion of ejected clumps through the dense envelope that often surrounds young gravitationally unstable protostellar disks. The ejected clumps either sit at the head of the tail-like structure or disperse if their mass is insufficient to withstand the head wind of the envelope. On the other hand, close encounters with quiescent protoplanetary disks produce three types of the tail-like structure; we define these as pre-collisional, post-collisional, and spiral tails. These tails can in principle be distinguished from one another by particular features of the gas and dust flow in and around them. We find that the brown-dwarf-mass intruders do not capture circumintruder disks during the encounter, while the subsolar-mass intruders can acquire appreciable circumintruder disks with elevated dust-to-gas ratios, which can ease their observational detection. However, this is true only for prograde collisions; the retrograde intruders fail to collect appreciable amounts of gas or dust from the disk of the target. The mass of gas in the tail varies in the range 0.85–11.8 MJup, while the total mass of dust lies in the 1.75–30.1 M⊕ range, with the spiral tails featuring the highest masses. The predicted mass of dust in the model tail-like structures is therefore higher than what was inferred for similar structures in SU Aur, FU Ori, and Z CMa, making their observational detection feasible.

Conclusions. Tail-like structures around protostellar and protoplanetary disks can be used to infer interesting phenomena such as clump ejection or close encounters. In particular, the bow-shock morphology of the tails could point to clump ejections as a possible formation mechanism. Further numerical and observational studies are needed to better understand the detectability and properties of the tails.
Nanomolded buried light-scattering (BLiS) back-reflectors using dielectric nanoparticles for light harvesting in thin-film silicon solar cells
Authors: Desta Derese , Rizzoli Rita , Summonte Caterina , Pereira Rui N. , Larsen Arne Nylandsted , Balling Peter , Ram Sanjay K.
Published: February 2020

The article presents a nanoparticle-based buried light-scattering (BLiS) back-reflector design realized through a simplified nanofabrication technique for the purpose of light-management in solar cells. The BLiS structure consists of a flat silver back-reflector with an overlying light-scattering bilayer which is made of a TiO2 dielectric nanoparticles layer with micron-sized inverted pyramidal cavities, buried under a flat-topped silicon nanoparticles layer. The optical properties of this BLiS back-reflector show high broadband and wide angular distribution of diffuse light-scattering. The efficient light-scattering by the buried inverted pyramid back-reflector is shown to effectively improve the short-circuit-current density and efficiency of the overlying n-i-p amorphous silicon solar cells up to 14% and 17.5%, respectively, compared to the reference flat solar cells. A layer of TiO2 nanoparticles with exposed inverted pyramid microstructures shows equivalent light scattering but poor fill factors in the solar cells, indicating that the overlying smooth growth interface in the BLiS back-reflector helps to maintain a good fill factor. The study demonstrates the advantage of spatial separation of the light-trapping and the semiconductor growth layers in the photovoltaic back-reflector without sacrificing the optical benefit.
Prédire la réponse à la vaccination contre la grippe
Authors: Gonçalves Elena , Combadière Béhazine
Published: February 2020

La vaccination est l’un des progrès majeurs de la médecine moderne. Mais afin d’améliorer l’efficacité des vaccins existants et d’en élaborer de nouveaux, nous devons mieux connaître les mécanismes d’action à l’origine de l’immunité protectrice et les stratégies vaccinales permettant d’induire une défense durable. La voie cutanée est une stratégie de vaccination importante, en raison de la richesse qu’elle présente en cellules de l’immunité innée qui ont un rôle clé dans la qualité, l’intensité et la persistance des réponses adaptatives qu’elles induisent. L’intégration des données biologiques obtenues au cours d’un essai clinique de vaccination antigrippale nous donne un aperçu de l’impact de la voie d’immunisation et de la signature innée sur la qualité des réponses immunitaires.
L’azadirachtine, un pesticide naturel aux effets multiples
Authors: Aribi Nadia , Denis Béatrice , Kilani-Morakchi Samira , Joly Dominique
Published: February 2020

Une littérature abondante traite de l’impact négatif des pesticides conventionnels, très efficaces dans la gestion des ravageurs mais responsables d’une large pollution environnementale. Les pesticides d’origine naturelle qui auraient un moindre impact environnemental suscitent ainsi un intérêt majeur. Parmi ceux-ci, l’azadirachtine, commercialisée sous diverses formulations (huile de neem, Neem-Azal, Bioneem, etc.) reste la molécule la plus recommandée dans les agro-écosystèmes. L’argument d’une innocuité environnementale de l’azadirachtine est cependant nuancé par des effets collatéraux qui, bien que controversés, sont notables sur des organismes non ciblés.
Aktuelle Standards in der Diagnostik und Therapie aggressiver B-Zell-Lymphome
Authors: Friedrichs Birte , Schmitz Norbert , Lenz Georg
Published: February 2020

Was ist neu?

Molekulare Charakterisierung aggressiver Lymphome Die sogenannte „cell of origin“-Klassifikation von diffusen großzelligen B-Zell-Lymphomen (DLBCL) ist mittlerweile Bestandteil der revidierten WHO-Klassifikation von 2017. Dabei werden ABC- und GCB-DLBCL unterschieden. In der Praxis erfolgt diese Einteilung in der Regel unter Anwendung der Immunhistochemie, wobei meist der sogenannte Hans-Algorithmus eingesetzt wird.

Erstlinientherapie von DLBCL-Patienten Die Hinzunahme verschiedener zielgerichteter Therapien konnte den Standard von 6–8 Zyklen R-CHOP-Chemoimmunotherapie bislang nicht verändern. Für junge Patienten bis 60 Jahre mit einem International Prognostic Index (IPI) von 0 kann die Therapie auf 4 Zyklen R-CHOP, gefolgt von 2 Applikationen Rituximab, reduziert werden.

Prophylaxe von ZNS-Rezidiven bei DLBCL-Patienten Eine intrathekale Therapie mit chemotherapeutischen Substanzen hat keinen Einfluss auf die Verhinderung von Rezidiven im Bereich des zentralen Nervensystems (ZNS). Die Anwendung des ZNS-IPI zur Identifizierung von Patienten mit hohem Risiko für ein ZNS-Rezidiv erscheint sinnvoll, auch wenn es hierzu keine Daten aus randomisierten Studien gibt. Für Patienten mit einem hohen Risiko können 2 systemische Zyklen mit hochdosiertem Methotrexat zusätzlich zur Erstlinientherapie empfohlen werden.

Behandlung von Patienten mit rezidiviertem oder therapierefraktärem DLBCL Patienten mit rezidiviertem und/oder refraktärem DLBCL erhalten eine Salvage-Chemotherapie, gefolgt von autologer oder allogener Stammzelltransplantation. Nach mindestens 2 Vortherapien sind aktuell 2 CAR-T-Zell-Produkte zugelassen. Dadurch erhalten auch ältere Patienten, die ggf. nicht für eine Transplantation infrage kommen, die Chance auf eine kurative Therapieoption.

Ausblick Neue Substanzgruppen wie Antikörper-Medikamenten-Konjugate oder bispezifische Antikörper zeigen in Studien von Patienten mit rezidiviertem oder therapierefraktärem DLBCL sehr vielversprechende Ergebnisse. Aktuell laufende klinische Studien prüfen den Einsatz weiterer neuer Substanzen.
Präventive Geriatrie: kognitiven Abbau verhindern
Authors: Meyer Anna Maria , Podolski Natalie , Pickert Lena , Polidori Maria Cristina
Published: February 2020

Prävention des kognitiven Abbaus Maßnahmen zur Früherkennung und zur Prävention des kognitiven Abbaus stehen im Vordergrund der Therapie. Im Gegensatz zur früheren Trennung zwischen neurodegenerativen und vaskulären Formen der Demenz wird aktuell die konsequente Therapie und Einstellung von kardiovaskulären Risikofaktoren angestrebt, um das Fortschreiten von möglicherweise allen Demenzformen zu verlangsamen. Die im Mai dieses Jahres von der Weltgesundheitsorganisation veröffentlichten Leitlinien geben Anhaltspunkte, wie dem Nachlassen der kognitiven Funktion mit zunehmendem Alter begegnet werden kann. Zu den Säulen der Prävention gehören eine ausgewogene Ernährung (für die Substitution einzelner, künstlicher Nährstoffe gibt es keine Evidenz), körperliche Aktivität (vor allem aerobes Training), ausreichender Schlaf, Konvivialität und soziale Interaktion (sensorische Störungen, gerade eine Beeinträchtigung des Hörens, dürfen nicht unterschätzt werden) sowie kognitive Aktivitäten und Übungen, die die allgemeinen, exekutiven und logischen Funktionen, die Denkgeschwindigkeit und das Arbeitsgedächtnis unterstützen.

Konsequenz für den klinischen Alltag Obwohl alle o. g. Bereiche des Lebensstils für die Prävention des kognitiven Abbaus wichtig sind, sind multidimensionale Interventionen nur dann für den Erhalt der Funktionen wirksam, wenn diese
Thromboseprophylaxe beim ambulanten Tumorpatienten
Authors: Hart Christina , Heudobler Daniel , Linnemann Birgit
Published: February 2020

Was ist neu?

Scores zur Stratifizierung des VTE-Risikos bei ambulanten Tumorpatienten Neben dem seit vielen Jahren bekannten Khorana-Score wurde kürzlich der CAT-Score publiziert, mit dem sich das Risiko für eine VTE innerhalb von 6 Monaten nach Einleitung einer Systemtherapie berechnen lässt. Als Berechnungsgrundlage dienen 2 Variablen: Tumorentität sowie Höhe der D-Dimere.

Prophylaxe mit niedermolekularem Heparin Für Tumorpatienten in der ambulanten Versorgung wird eine Thromboseprophylaxe derzeit routinemäßig nicht empfohlen. Eine Stratifizierung des VTE-Risikos vor Einleitung einer Systemtherapie sollte erfolgen. Weitere Risikofaktoren, die in die publizierten Scores nicht eingehen, z. B. VTE in der Anamnese oder Therapie mit antiangiogenen Substanzen, sollten berücksichtigt werden. Eine Prophylaxe mit NMH kann nach individueller Nutzen-Risiko-Abwägung bei Patienten mit erhöhtem VTE-Risiko und vertretbarer Erhöhung des Blutungsrisikos erwogen werden.

Direkte orale Antikoagulanzien zur VTE-Prophylaxe In 2 Studien konnte kürzlich gezeigt werden, dass Rivaroxaban und Apixaban wirksam sind in der Verhinderung einer VTE beim ambulanten Tumorpatienten. Das Risiko für schwere Blutungen war hierbei erhöht. Rivaroxaban und Apixaban sind in dieser Indikation bislang nicht zugelassen.

VTE-Prophylaxe bei Patienten mit multiplem Myelom Eine VTE-Prophylaxe ist bei Patienten mit multiplem Myelom, die unter Therapie mit Thalidomid oder Lenalidomid in Kombination mit hochdosiertem Dexamethason und/oder einem Anthrazyklin stehen, fest etabliert. Je nach zugrunde liegender Risikostratifizierung wird eine Prophylaxe mit Aspirin bei niedrigem Risiko oder NMH bei hohem Risiko empfohlen.
Asymptomatic and Unnoticed Intra-articular Screw Over 18 Years after Fracture of the Posterior Wall of the Acetabulum – a Question of Stability?
Authors: Audretsch Christof K. , Schmidutz Florian , Küper Markus Alexander
Published: February 2020

Fractures of the posterior wall of the acetabulum occur in a frequency of 25 – 30%. Multifragmentary fractures involving 40 – 50% of the acetabular surface, the quality of reduction as well as involvement of cartilage and acetabular labrum are considered to have an impact on the development of a reduced posterior stability of the hip joint. This results in a shift of the main weight bearing area with development of a posttraumatic osteoarthritis. In the presented case, a 42-year old male patient was operated on 18 years ago due to a posterior acetabular wall fracture. Retrospectively, one of the screws was located partially intraarticular. However, the patient was asymptomatic over the 18-year period. The first consultation was due to unspecific symptoms of osteoarthritis of the right hip joint especially during flexion and external rotation. Due to only mild radiological signs of osteoarthritis, we indicated only the removal of the intraarticular screw. The symptoms
postoperatively switched to a feeling of instability, so a total hip arthroplasty was performed. Since the operation, the patient is asymptomatic regarding the hip joint. The intraarticular screw seemed to stabilize the hip joint. This case demonstrates the importance of a good posterior guidance for the stability of the hip joint on one hand. On the other hand, it demonstrates the minor stress load of the posterior acetabular region, especially after fracture of the posterior wall. Therefore, a good posterior guidance should be one major aim of treatment of posterior acetabular wall fractures.
Effect of Tranexamic Acid on Coagulation and Fibrin Clot Properties in Children Undergoing Craniofacial Surgery
Authors: Fenger-Eriksen Christian , Lindholm Alexander D'Amore , Krogh Lisbeth , Hell Tobias , Berger Martin , Hermann Martin , Fries Dietmar , Juul Niels , Rasmussen Mads , Hvas Anne-Mette
Published: February 2020

Objective Craniosynostosis surgery in small children is very often associated with a high blood loss. Tranexamic acid (TXA) reduces blood loss during this procedure, although the potential underlying coagulopathy in these children is not known in detail. Objective was to determine the nature of any coagulopathy found during and after craniosynostosis surgery and to characterize the effect of TXA on fibrin clot formation, clot strength, and fibrinolysis.

Materials and Methods Thirty children received either TXA (bolus dose of 10 mg/kg followed by 8 hours continuous infusion of 3 mg/kg/h) or placebo. Dynamic whole blood clot formation assessed by thromboelastometry, platelet count, dynamic thrombin generation/thrombin-antithrombin, clot lysis assay, and fibrinogen/factor XIII (FXIII) levels were measured. Additionally, clot structure was investigated by real-time live confocal microscopy and topical data analysis.

Results Increased ability of thrombin generation was observed together with a tendency toward shortened activated partial thromboplastin time and clotting time. Postoperative maximum clot firmness was higher among children receiving TXA. FXIII decreased significantly during surgery in both groups.

Resistance toward tissue plasminogen activator-induced fibrinolysis was higher in children that received TXA, as evidenced by topical data analysis and by a significant longer lysis time. Fibrinogen levels were higher in the TXA group at 24 hours.

Conclusion A significant coagulopathy mainly characterized by changes in clot stability and not parameters of thrombin generation was reported. Tranexamic acid improved clot strength and reduced fibrinolysis, thereby avoiding reduction in fibrinogen levels.
Evaluating an Image-Guided Operating Room with Cone Beam CT for Skull Base Surgery
Authors: Muhanna Nidal , Douglas Catriona M. , Daly Michael J. , Chan Harley H.L. , Weersink Robert , Townson Jason , Monteiro Eric , Yu Eugene , Weimer Emilie , Kucharczyk Walter , Jaffray David A. , Irish Jonathan C. , de Almeida John R.
Published: February 2020

Importance Skull base surgery requires precise preoperative assessment and intraoperative management of the patient. Surgical navigation is routinely used for complex skull base cases; however, the image guidance is commonly based on preoperative scans alone.

Objective The primary objective of this study was to assess the image quality of intraoperative cone-beam computed tomography (CBCT) within anatomical landmarks used in sinus and skull base surgery. The secondary objective was to assess the registration error of a surgical navigation system based on intraoperative CBCT.

Design Present study is a retrospective case series of image quality after intraoperative cone beam CT.

Setting The study was conducted at Toronto General Hospital and Princess Margaret Cancer Centre, University Health Network, Toronto.

Participants A total of 46 intraoperative scans (34 patients, 21 skull base, 13 head and neck) were studied.

Main Outcome and Measures Thirty anatomical landmarks (vascular, soft tissue, and bony) within the sinuses and anterior skull base were evaluated for general image quality characteristics: (1) bony detail visualization; (2) soft-tissue visualization; (3) vascular visualization; and (4) freedom from artifacts (e.g., metal). Levels of intravenous (IV) contrast enhancement were quantified in Hounsfield's units (HU). Standard paired-point registration between imaging and tracker coordinates was performed using 6 to 8 skin fiducial markers and the corresponding fiducial registration error (FRE) was measured.

Results Median score for bony detail on CBCT was 5, remaining at 5 after administration of IV contrast. Median soft-tissue score was 2 for both pre- and postcontrast. Median vascular score was 1 precontrast and 3 postcontrast. Median score for artifacts on CBCT were 2 for both pre-and postcontrast, and metal objects were noted to be the most significant source of artifact. Intraoperative CBCT allowed preresection images and immediate postresection images to be available to the skull base surgeon. There was a significant improvement in mean (standard deviation [SD]) CT intensity in the left carotid artery postcontrast 334 HU (67 HU) (p < 10−10). The mean FRE was 1.8 mm (0.45 mm).

Conclusion Intraoperative CBCT in complex skull base procedures provides high-resolution bony detail allowing immediate assessment of complex resections. The use of IV contrast with CBCT improves the visualization of vasculature. Image-guidance based on CBCT yields registration errors consistent with standard techniques.
Screening for the Most Common Mutations of CFTR Gene among Egyptian Children with Difficult-to-Treat Asthma
Authors: Al-Haggar Mohammad , Osman Engy , Eid Abdel-Rahman , Barakat Tarek , El-Morsi Samar
Published: February 2020

Cystic fibrosis (CF) is panethnic autosomal recessive disease that affects the exocrine glands of pancreas, lungs, and intestine. It is often misdiagnosed in developing countries as difficult-to-treat asthma. We enrolled 150 Egyptian families with one or more probands who were complaining of difficult-to-treat asthma, and 112 cases were studied extensively through history taking including pedigree construction and clinical examination. In addition, spirometry and computed tomography of the chest were done in selected cases. All cases were subjected to quantitative sweat chloride test and molecular screening for the three most common mutations of cystic fibrosis transconductance regulator (CFTR) gene (ΔF508, G542X, W1282X) using amplification refractory mutation system (ARMS) technique. Probands of difficult-to-treat asthma comprised 66 males and 46 females; their age range was 1 to 14 years. Sixty-one probands (54.5%) were carriers of one or more of the studied mutations (36 cases and 25 carriers). Six carriers of single mutations had mild respiratory symptoms and negative sweat test. The most common allele was ΔF508, 60 alleles in 56 individuals (4 were homozygous ΔF508/ΔF508) followed by W1282X in 25 individuals and G542X in 12 individuals. Allele W1282X had an increased risk of recurrent chest infection and bronchiectasis. Moreover, cases with two mutations had more severe symptoms compared with those with a single mutation. CFTR mutations and CF-related syndromes are not rare as thought in Egypt, especially among the high-risk difficult-to-treat asthma. The readily available ARMS technique is recommended for ΔF508 and/or W1282X screening on priority basis among these children.
Online customer behavior: perceptions regarding the types of risks incurred through online purchases
Authors: Marceda Bach Tatiana , da Silva Wesley Vieira , Mendonça Souza Adriano , Kudlawicz-Franco Claudineia , da Veiga Claudimar Pereira
Published: February 2020

Abastract

Deciding to make online purchases can be risky and retailers have an opportunity to influence the consumer’s decision-making process. The aim of this article is to gauge the impact of different types of risks on trust and decision making with regard to online purchases. We conducted a survey with adaptations to three theoretical scales. To analyze the impact of risk on the variables of trust and decision making, a confirmatory factor analysis was performed, and to clarify the relationships between these constructs, a structural equation model was prepared. A qualitative (n = 13) and quantitative study were conducted with primary data (n = 328) collected by means of a structured questionnaire using a sample of a group of consumers who reside in the south of Brazil. The article makes four main contributions to the field: (i) it identifies the influence of three latent constructs that might affect online purchase behavior; (ii) it gauges the risks associated with the latent construct of trust and the adaptation of scales of perceived risk and decision making; (iii) it highlights the need to reassess the strategies adopted by companies that sell online to reduce risks and consequently increase trust in decision making; and (iv) it evaluates the demographic variables that have a significant moderating effect on the relationships of the constructs of trust and decision making during the purchase process.
Equivalence of electric, magnetic, and electromagnetic Chern numbers for topological photonic crystals
Authors: De Nittis Giuseppe , Lein Max
Published: February 2020

Haldane [S. Raghu and F. D. M. Haldane, Phys. Rev. A 78, 033834 (2008)] predicted an analog of the integer quantum Hall effect in gyrotropic photonic crystals, where the net number of electromagnetic edge modes moving left-to-right is given by a bulk Chern number. His prediction—topological effects are bona fide wave and not quantum phenomena—has been confirmed in a number of experiments [Z. Wang et al., Nature 461, 772–775 (2009)]. However, theoretical physicists have tacitly used three different definitions for the bulk Chern numbers that enter the bulk-edge correspondence—on the basis of electromagnetic Bloch functions, electric Bloch functions, and magnetic Bloch functions. We use vector bundle theoretic arguments to prove that in media such as those considered by Haldane, these three potentially different Chern numbers necessarily agree with one another, and consequently, any one of them can be used in Haldane’s photonic bulk-edge correspondence.