bluuebunny/crossref_metadata_2025 huggingface dataset:
Memórias coletivas em disputa: o embate entre memórias e estratégias identitárias em entrevistas jornalísticas
Authors: Mariano Agnes Francine de Carvalho
Published: April 2020

O debate parte da premissa de que memórias constroem identidades, assim como são atravessadas por estratégias identitárias. Buscaremos aqui percorrer estudos sobre as relações entre a memória e a identidade, iluminando aspectos como diferentes manifestações da memória e relações entre memória e pertencimentos grupais, para chegarmos ao tema da circulação de diferentes memórias numa sociedade, podendo resultar em disputas de memórias. Como exemplo, observaremos trechos de uma entrevista em que o então candidato à vice-presidência general Hamilton Mourão e a jornalista Miriam Leitão expressam diferentes memórias a respeito do regime militar no Brasil. O que nos conduz a analisar riscos e vantagens das memórias abertas, que aceitam a existência de outras memórias, e fechadas, que buscam silenciar memórias divergentes.
Impressos, discursos e moralidade nos regimes autoritários instituídos no Brasil
Authors: Zaluski Jorge Luiz
Published: April 2020

Resenha da obra:COWAN, Benjamin A. Securing sex: morality and repression in the making of Cold War Brazil. Chapel Hill, NC: University of North Carolina Press, 2016.
Carbon and nitrogen ratio in the soils of the lithalsa landscapes in Sentsa River valley, East Sayan
Authors: Vasil'chuk Alla Constantinovna , Vasil'chuk Jessica Yur'evna , Budantseva Nadine Arkad'evna , Vasil'chuk Yurij Kirillovich , Terskaya Elena Vyacheslavovna , Krechetov Pavel Petrovich , Bludushkina Lyubov' Bakhtiyarovna
Published: April 2020

The subject of this study is the ratio of carbon and nitrogen content in the soil of the lithalsa landscape in the Sentsa River valley. The focus is on the spatial distribution of C/N ratio in the genetic soil horizons: humus (A), illuvial (B), the parent rock(C), as well as in the buried peat horizon (T). The carbon and nitrogen content is analyzed in 70 samples using the element analyzer C, H, N, S –O EA 1110. Sample preparation included drying the soil through a sieve and grinding it with a rubber pestle in a porcelain mortar. It is found that cryogenic concentration of soil solutions, cryogenic heaving, thermokarst, zoogenic turbations, peat burial, and alluvial loam deposition are the main processes determining the peculiarity of soil formation within lithalsa landscapes. The maximum variation in the ratio of carbon and nitrogen content is observed in the illuvial horizon, while in the humus horizon and in the parent rock, as well as in the buried peat horizon, this indicator is of a smaller range.
Some peculiarities of opera libretto as a potential literary genre
Authors: Poliakov Ilia Aruslanovich
Published: April 2020

This article analyzes the changes pertaining to such level of literary works as a system of characters, category of space and time, phonetic system and composition; as well as changes in epic and dramatic oeuvres in the process of transformation of the text of literary work into an opera libretto. Analysis is conducted on peculiarities of the aforementioned levels of literary text and libretto. As an example of epic work, the author selected the A. S. Pushkin’s verse novel “Eugene Onegin” and the eponymous opera composed by P. I. Tchaikovsky; as an example of dramatic work, the author picked the two poetic dramas from Pushkin’s cycle “The Stone Guest” and “The Miserly Knight” and the eponymous operas by A. Dargomyzhsky and S. V. Rachmaninoff respectively. The following methods were applied in the course of this study: comparative based on juxtaposition of musical-scenic interpretation and precedent literary text; typological for determination of patterns, classification and generalization of the results. The author comes to the conclusion that the transformation of epic and dramatic literary texts into the opera libretto has similarities and differences on all levels of the text. The possible reasons of such phenomenon are discussed. The author answers a question whether or not libretto can be attributed to as a genre of fiction writing.
Optogenetic control of excitatory post-synaptic differentiation through neuroligin-1 tyrosine phosphorylation
Authors: Letellier Mathieu , Lagardère Matthieu , Tessier Béatrice , Janovjak Harald , Thoumine Olivier
Published: April 2020

Neuroligins (Nlgns) are adhesion proteins mediating trans-synaptic contacts in neurons. However, conflicting results around their role in synaptic differentiation arise from the various techniques used to manipulate Nlgn expression level. Orthogonally to these approaches, we triggered here the phosphorylation of endogenous Nlgn1 in CA1 mouse hippocampal neurons using a photoactivatable tyrosine kinase receptor (optoFGFR1). Light stimulation for 24 hr selectively increased dendritic spine density and AMPA-receptor-mediated EPSCs in wild-type neurons, but not in Nlgn1 knock-out neurons or when endogenous Nlgn1 was replaced by a non-phosphorylatable mutant (Y782F). Moreover, light stimulation of optoFGFR1 partially occluded LTP in a Nlgn1-dependent manner. Combined with computer simulations, our data support a model by which Nlgn1 tyrosine phosphorylation promotes the assembly of an excitatory post-synaptic scaffold that captures surface AMPA receptors. This optogenetic strategy highlights the impact of Nlgn1 intracellular signaling in synaptic differentiation and potentiation, while enabling an acute control of these mechanisms.
Pre-stimulus phase and amplitude regulation of phase-locked responses are maximized in the critical state
Authors: Avramiea Arthur-Ervin , Hardstone Richard , Lueckmann Jan-Matthis , Bím Jan , Mansvelder Huibert D , Linkenkaer-Hansen Klaus
Published: April 2020

Understanding why identical stimuli give differing neuronal responses and percepts is a central challenge in research on attention and consciousness. Ongoing oscillations reflect functional states that bias processing of incoming signals through amplitude and phase. It is not known, however, whether the effect of phase or amplitude on stimulus processing depends on the long-term global dynamics of the networks generating the oscillations. Here, we show, using a computational model, that the ability of networks to regulate stimulus response based on pre-stimulus activity requires near-critical dynamics—a dynamical state that emerges from networks with balanced excitation and inhibition, and that is characterized by scale-free fluctuations. We also find that networks exhibiting critical oscillations produce differing responses to the largest range of stimulus intensities. Thus, the brain may bring its dynamics close to the critical state whenever such network versatility is required.
R-spondin signalling is essential for the maintenance and differentiation of mouse nephron progenitors
Authors: Vidal Valerie PI , Jian-Motamedi Fariba , Rekima Samah , Gregoire Elodie P , Szenker-Ravi Emmanuelle , Leushacke Marc , Reversade Bruno , Chaboissier Marie-Christine , Schedl Andreas
Published: April 2020

During kidney development, WNT/β-catenin signalling has to be tightly controlled to ensure proliferation and differentiation of nephron progenitor cells. Here, we show in mice that the signalling molecules RSPO1 and RSPO3 act in a functionally redundant manner to permit WNT/β-catenin signalling and their genetic deletion leads to a rapid decline of nephron progenitors. By contrast, tissue specific deletion in cap mesenchymal cells abolishes mesenchyme to epithelial transition (MET) that is linked to a loss of Bmp7 expression, absence of SMAD1/5 phosphorylation and a concomitant failure to activate Lef1, Fgf8 and Wnt4, thus explaining the observed phenotype on a molecular level. Surprisingly, the full knockout of LGR4/5/6, the cognate receptors of R-spondins, only mildly affects progenitor numbers, but does not interfere with MET. Taken together our data demonstrate key roles for R-spondins in permitting stem cell maintenance and differentiation and reveal Lgr-dependent and independent functions for these ligands during kidney formation.
Opponent regulation of action performance and timing by striatonigral and striatopallidal pathways
Authors: Bakhurin Konstantin I , Li Xiaoran , Friedman Alexander D , Lusk Nicholas A , Watson Glenn DR , Kim Namsoo , Yin Henry H
Published: April 2020

The basal ganglia have been implicated in action selection and timing, but the relative contributions of the striatonigral (direct) and striatopallidal (indirect) pathways to these functions remain unclear. We investigated the effects of optogenetic stimulation of D1+ (direct) and A2A+ (indirect) neurons in the ventrolateral striatum in head-fixed mice on a fixed time reinforcement schedule. Direct pathway stimulation initiates licking, whereas indirect pathway stimulation suppresses licking and results in rebound licking after stimulation. Moreover, direct and indirect pathways also play distinct roles in timing. Direct pathway stimulation produced a resetting of the internal timing process, whereas indirect pathway stimulation transiently paused timing, and proportionally delayed the next bout of licking. Our results provide evidence for the continuous and opposing contributions of the direct and indirect pathways in the production and timing of reward-guided behavior.
Serotonin signaling by maternal neurons upon stress ensures progeny survival
Authors: Das Srijit , Ooi Felicia K , Cruz Corchado Johnny , Fuller Leah C , Weiner Joshua A , Prahlad Veena
Published: April 2020

Germ cells are vulnerable to stress. Therefore, how organisms protect their future progeny from damage in a fluctuating environment is a fundamental question in biology. We show that in Caenorhabditis elegans, serotonin released by maternal neurons during stress ensures the viability and stress resilience of future offspring. Serotonin acts through a signal transduction pathway conserved between C. elegans and mammalian cells to enable the transcription factor HSF1 to alter chromatin in soon-to-be fertilized germ cells by recruiting the histone chaperone FACT, displacing histones, and initiating protective gene expression. Without serotonin release by maternal neurons, FACT is not recruited by HSF1 in germ cells, transcription occurs but is delayed, and progeny of stressed C. elegans mothers fail to complete development. These studies uncover a novel mechanism by which stress sensing by neurons is coupled to transcription response times of germ cells to protect future offspring.
Microstructure and Mechanical Properties of the As‐Cast AlLiCuMgZr Alloy with High Li Content and Different Cu/Mg Ratios
Authors: Yu Tianfu , Qian Bingyu , Wu Ruizhi , Sun Jianfeng , Zhao Hui
Published: April 2020

The microstructures and mechanical properties of as‐cast AlLiCuMgZr alloys with high Li content and different Cu/Mg ratios are investigated. The results show that the tensile strength increases and the elongation almost keeps unchanged, with the decrease in Cu/Mg ratio. The tensile fracture exhibits typical intergranular fracture. The main phases of as‐cast alloys are α(Al), δ′(Al3Li), and T2(Al6Li3Cu). With the decrease in Cu/Mg ratio, the size of the δ′(Al3Li) phase increases, and the amount of T2(Al6Li3Cu) phase at the grain boundary decreases. Moreover, the fine S1(Al2MgLi) phase and S′(Al2CuMg) phase are formed inside the grains near the grain boundaries. The improved properties are attributed to the solution strengthening and second‐phase strengthening of δ′(Al3Li).
Nanopatterned Nafion Microelectrode Arrays for In Vitro Cardiac Electrophysiology
Authors: Choi Jong Seob , Smith Alec S. T. , Williams Nisa P. , Matsubara Tatsuya , Choi Minji , Kim Joon‐Wan , Kim Hyung Jin , Choi Seungkeun , Kim Deok‐Ho
Published: April 2020

In this study, nanopatterned Nafion microelectrode arrays for in vitro cardiac electrophysiology are reported. With the aim of defining sophisticated Nafion nanostructures with highly ionic conductivity, fabrication parameters such as Nafion concentration and curing temperature are optimized. By increasing curing temperature and Nafion concentration, the replication fidelity of Nafion nanopatterns when copied from a polydimethylsiloxane master mold are controlled. It is also found that cross‐sectional morphology and ion current density of nanopatterned Nafion strongly depends on the fabrication parameters. To investigate this dependency, current‐voltage analysis is conducted using organic electrochemical transistors overlaid with patterned Nafion substrates. Nanopatterned Nafion is found to allow higher ion current densities than unpatterned surfaces. Furthermore, higher curing temperatures are found to render Nafion layers with higher ion/electrical transfer properties. To optimize nanopattern dimensions, electrical current flows, and film uniformity, a final configuration consisting of 5% nanopatterned Nafion cured at 65 °C is chosen. Microelectrode arrays (MEAs) are then covered with optimized Nafion nanopatterns and used for electrophysiological analysis of two types of induced pluripotent stem cell‐derived cardiomyocytes (iPSCs‐CMs). These data highlight the suitability of nanopatterned Nafion, combined with MEAs, for enhancing the cellular environment of iPSC‐CMs for use in electrophysiological analysis in vitro.
Flexible Nb4C3Tx Film with Large Interlayer Spacing for High‐Performance Supercapacitors
Authors: Zhao Shuangshuang , Chen Chaofan , Zhao Xin , Chu Xuefeng , Du Fei , Chen Gang , Gogotsi Yury , Gao Yu , Dall'Agnese Yohan
Published: April 2020

MXenes derived from 413 MAX phases are rarely studied but they have the potential to have superior electrical and mechanical properties thanks to a thicker monolayer (four layers of transition metal and three layers of carbon or nitrogen). In this paper, Nb4C3Tx MXene nanosheets are delaminated and freestanding film with 1.77 nm interlayer spacing is obtained, which is larger than that of most previous MXenes. When Nb4C3Tx freestanding films are tested as supercapacitors electrodes, Nb4C3Tx shows high volumetric capacitance, 1075, 687, and 506 F cm−3 in 1 m H2SO4, 1 m KOH, and 1 m MgSO4, respectively, at the scan rate of 5 mV s−1. An in situ X‐ray diffraction technique is used to study the structural changes during the electrochemical charging in 1 m H2SO4 and 1 m MgSO4. There is almost no change in the 21 Å interlayer spacing during the cycling, because the space between the MXene layers is sufficient to accommodate the insertion and deinsertion of cations. This can lead to stable performance of Nb4C3Tx MXene energy storage devices.
Nitrogen‐Doped Ti3C2 MXene: Mechanism Investigation and Electrochemical Analysis
Authors: Lu Chengjie , Yang Li , Yan Bingzhen , Sun Liangbo , Zhang Peigen , Zhang Wei , Sun ZhengMing
Published: April 2020

Nitrogen doping has been proven to be a facile modification strategy to improve the electrochemical performance of 2D MXenes, a group of promising candidates for energy storage applications. However, the underlying mechanisms, especially the positions of nitrogen dopants, and its effect on the electrical properties of MXenes, are still largely unexplored. Herein, a comprehensive study is carried out to disclose the nitrogen doping mechanism in Ti3C2 MXene, by employing theoretical simulation and experimental characterization. Three possible sites are found in Ti3C2Tx (T = F, OH, and O) to accommodate the nitrogen dopants: lattice substitution (for carbon), function substitution (for –OH), and surface absorption (on –O). Moreover, electrochemical test results confirm that all the three kinds of nitrogen dopants are favorable for improving the specific capacitance of the Ti3C2 electrode, and the underlying factors are successfully distinguished. By revealing the nitrogen doping mechanisms in Ti3C2 MXene, this work provides theoretical guidelines for modulating the electrochemical properties of MXene materials for energy storage applications.
2D MXenes for Electromagnetic Shielding: A Review
Authors: Iqbal Aamir , Sambyal Pradeep , Koo Chong Min
Published: April 2020

Since the first report on electromagnetic interference (EMI) shielding of 2D Ti3C2Tx in 2016, MXenes have captured the leadership position among lightweight shielding materials due to many advantages, including their excellent shielding performance, outstanding metallic conductivity, low density, large specific surface area, tunable surface chemistry, and solution processability. MXenes triggered a huge interest in the materials research community, leading to over 100 reported publications on MXenes' EMI shielding within 3 years. Many MXenes composites and hybrids in different structural forms, such as compact and laminate structures, layer‐by‐layer assemblies, porous foams and aerogels, and segregated structures, have been explored to further improve the intrinsic EMI shielding properties of MXenes. This article comprehensively reviews the recent advancements in MXene‐based EMI shielding materials with different structural morphologies and provides an insight into future challenges and guidelines for finding material solutions for the next‐generation shielding applications.
Secondary Bonds Modifying Conjugate‐Blocked Linkages of Biomass‐Derived Lignin to Form Electron Transfer 3D Networks for Efficiency Exceeding 16% Nonfullerene Organic Solar Cells
Authors: Hu Hui‐Chao , Xu Huimin , Wu Junying , Li Lijuan , Yue Fengxia , Huang Liulian , Chen Lihui , Zhang Xingye , Ouyang Xinhua
Published: April 2020

Fabricating high‐efficient electron transporting interfacial layers (ETLs) with isotropic features is highly desired for all‐directional electron transfer/collection from an anisotropic active layer, achieving excellent power conversion efficiency (PCEs) on nonfullerene acceptor (NFA) organic solar cells (OSCs). The complicated synthesis and cost‐consumption in exploring versatile materials arouse great interest in the development of binary‐doping interlayers without phase separation and flexible manipulation. Herein, for the first time, a novel cathode interfacial layer based on biomass‐derived demethylated kraft lignin (DMeKL) is proposed. Features of multiple phenolic‐hydroxyl (PhOH) and uniform‐distributed render DMeKL to exhibit an excellent bonding capacity with amino terminal substituted perylene diiminde (PDIN), and successfully form a high‐efficient isotropic electron transfer 3D network. Synchronously, secondary bonds completely modify conjugate‐blocked linkages of DMeKL, significantly enhance the electron transporting performance on cross‐section and vertical‐sections, and repair the contact of PDIN with active layer. The DMeKL/PDIN‐based 3D‐network exhibits well‐matched work function (WF) (–4.34 eV) with cathode (–4.30 eV) and energy level of electron acceptor (–4.11 eV). DMeKL/PDIN‐based NFAs‐OSC shows excellent short‐circuit current density (26.61 mA cm–2) and PCE (16.02%) beyond the classic PDIN‐based NFA‐OSC (25.64 mA cm–2, 15.41%), which is the highest PCEs among biomaterials interlayers. The results supply a novel method to achieve high‐efficient cathode interlayer for NFAs‐OSCs.
Orthotopic Bone Regeneration within 3D Printed Bioceramic Scaffolds with Region‐Dependent Porosity Gradients in an Equine Model
Authors: Diloksumpan Paweena , Bolaños Rafael Vindas , Cokelaere Stefan , Pouran Behdad , de Grauw Janny , van Rijen Mattie , van Weeren René , Levato Riccardo , Malda Jos
Published: April 2020

The clinical translation of three‐dimensionally printed bioceramic scaffolds with tailored architectures holds great promise toward the regeneration of bone to heal critical‐size defects. Herein, the long‐term in vivo performance of printed hydrogel‐ceramic composites made of methacrylated‐oligocaprolactone‐poloxamer and low‐temperature self‐setting calcium‐phosphates is assessed in a large animal model. Scaffolds printed with different internal architectures, displaying either a designed porosity gradient or a constant pore distribution, are implanted in equine tuber coxae critical size defects. Bone ingrowth is challenged and facilitated only from one direction via encasing the bioceramic in a polycaprolactone shell. After 7 months, total new bone volume and scaffold degradation are significantly greater in structures with constant porosity. Interestingly, gradient scaffolds show lower extent of remodeling and regeneration even in areas having the same porosity as the constant scaffolds. Low regeneration in distal regions from the interface with native bone impairs ossification in proximal regions of the construct, suggesting that anisotropic architectures modulate the cross‐talk between distant cells within critical‐size defects. The study provides key information on how engineered architectural patterns impact osteoregeneration in vivo, and also indicates the equine tuber coxae as promising orthotopic model for studying materials stimulating bone formation.
Mechanochemical Patternable ECM‐Mimetic Hydrogels for Programmed Cell Orientation
Authors: Lavrador Pedro , Gaspar Vítor M. , Mano João F.
Published: April 2020

Native human tissues are supported by a viscoelastic extracellular matrix (ECM) that can adapt its intricate network to dynamic mechanical stimuli. To recapitulate the unique ECM biofunctionality, hydrogel design is shifting from typical covalent crosslinks toward covalently adaptable networks. To pursue such properties, herein hybrid polysaccharide‐polypeptide networks are designed based on dynamic covalent assembly inspired by natural ECM crosslinking processes. This is achieved through the synthesis of an amine‐reactive oxidized‐laminarin biopolymer that can readily crosslink with gelatin (oxLAM‐Gelatin) and simultaneously allow cell encapsulation. Interestingly, the rational design of oxLAM‐Gelatin hydrogels with varying aldehyde‐to‐amine ratios enables a refined control over crosslinking kinetics, viscoelastic properties, and degradability profile. The mechanochemical features of these hydrogels post‐crosslinking offer an alternative route for imprinting any intended nano‐ or microtopography in ECM‐mimetic matrices bearing inherent cell‐adhesive motifs. Different patterns are easily paved in oxLAM‐Gelatin under physiological conditions and complex topographical configurations are retained along time. Human adipose‐derived mesenchymal stem cells contacting mechanically sculpted oxLAM‐Gelatin hydrogels sense the underlying surface nanotopography and align parallel to the anisotropic nanoridge/nanogroove intercalating array. These findings demonstrate that covalently adaptable features in ECM‐mimetic networks can be leveraged to combine surface topography and cell‐adhesive motifs as they appear in natural matrices.
High‐Rate Printing of Micro/Nanoscale Patterns Using Interfacial Convective Assembly
Authors: Chai Zhimin , Korkmaz Adnan , Yilmaz Cihan , Busnaina Ahmed A.
Published: April 2020

Printing of electronics has been receiving increasing attention from academia and industry over the recent years. However, commonly used printing techniques have limited resolution of micro‐ or sub‐microscale. Here, a directed‐assembly‐based printing technique, interfacial convective assembly, is reported, which utilizes a substrate‐heating‐induced solutal Marangoni convective flow to drive particles toward patterned substrates and then uses van der Waals interactions as well as geometrical confinement to trap the particles in the pattern areas. The influence of various assembly parameters including type of mixing solvent, substrate temperature, particle concentration, and assembly time is investigated. The results show successful assembly of various nanoparticles in patterns of different shapes with a high resolution down to 25 nm. In addition, the assembly only takes a few minutes, which is two orders of magnitude faster than conventional convective assembly. Small‐sized (diameter below 5 nm) nanoparticles tend to coalesce during the assembly process and form sintered structures. The fabricated silver nanorods show single‐crystal structure with a low resistivity of 8.58 × 10−5 Ω cm. With high versatility, high resolution, and high throughput, the interfacial convective assembly opens remarkable opportunities for printing next generation nanoelectronics and sensors.
Surface Evolution of Lithium Titanate upon Electrochemical Cycling Using a Combination of Surface Specific Characterization Techniques
Authors: Rikarte Jokin , Acebedo Begoña , Vilalta‐Clemente Arantxa , Bonilla Francisco , Wilkinson Angus J. , Galceran Montserrat , Lousa Arturo , Rubio‐Zuazo Juan , Muñoz‐Márquez Miguel Ángel
Published: April 2020

Among the electrodes for Li‐ion batteries, Li4Ti5O12 (LTO) stands out as anode owing to its stability and safety, in part ascribed to its low surface reactivity. However, the overlayer formation on the LTO surface upon electrochemical cycling is reported in recent years; a rough surface layer of electrochemically inactive α‐Li2TiO3 on top of the LTO (111) surface is suggested on the grounds of scanning probe techniques and theoretical ab initio calculations which would negatively strike on the battery performance. Hence the investigation of the LTO surface evolution is key to achieve more stable and safer Li‐ion batteries. LTO (111) thin film electrodes are used as model system where a variety of surface specific characterization techniques are applied to unveil the surface behavior of LTO in Li‐ion batteries. In contrast with previous studies, with the help of high‐resolution transmission electron microscopy and synchrotron‐based surface X‐ray diffraction, α‐Li2TiO3 is found to be a surface preparation product. Of special importance is the use of high‐resolution electron backscatter diffraction to report an increase on the LTO surface strain upon electrochemical cycling which can have a critical effect in long cycling performance of LTO that is always considered a zero‐strain material.
Wide Line Surface‐Enhanced Raman Scattering Mapping
Authors: Ilchenko Oleksii , Slipets Roman , Rindzevicius Tomas , Durucan Onur , Morelli Lidia , Schmidt Michael S. , Wu Kaiyu , Boisen Anja
Published: April 2020

Surface‐enhanced Raman spectroscopy (SERS)‐based molecular detection at extremely low concentrations often relies on mapping of a SERS substrate. This yields a large number (>1000) of SERS spectra that can improve the limit of detection; however, the signal collection time is a major constraint. In this work, a wide line (WL) laser focusing technique aimed at fast mapping of SERS substrates is presented. The WL technique enables acquisition of thousands of SERS spectra in a few seconds without missing any of the electromagnetic “hot spots” in the illuminated area. In addition, the SERS signal averaging across the line in the WL mode displays extremely high signal‐to‐noise ratios. The advantages of the WL technique for SERS‐based sensing are verified using different analyte molecules, that is, p‐coumaric acid and melamine. Results show that the limit of detection can be improved by one order of magnitude compared to results obtained using a commercial Raman microscope.
Adaptability evaluation of ORYZA (v3) for single‐cropped rice under different establishment techniques in eastern China
Authors: Lu Bihui , Yu Kun , Wang Zhiming , Wang Jing , Shan Jie
Published: April 2020

The ORYZA (v3) rice model is the most exhaustive representation of the available knowledge on rice (Oryza sativa L.) growth and development and has become an integrated rice modelling tool suitable for different scenarios according to the demands of users. A 3‐yr field experiment was conducted under potential production conditions for single‐cropped rice during 2011–2013 in Jiangsu Province in eastern China. The simulation performance of ORYZA (v3) with respect to the growth and development of different rice varieties under different establishment methods was evaluated and validated. The adaptability and stability of the model and its effect on the production of the same or similar rice varieties in different districts and years were verified using calibrated parameters. The results revealed that ORYZA (v3) performed well in simulating the dynamics of crop biomass and leaf area index for both calibration and validation datasets in 2011–2013, as is reflected by the high adjusted linear correlation coefficient (r2), low normalized root mean square error (NRMSE) value, and lack of notable differences between simulated and observed data with 99% confidence. The NRMSE value of the final yield ranged from 4.30 to 8.99% for both Indica and Japonica rice throughout the growing seasons. The performance of transplanted Indica rice varieties was better than that of most Japonica rice varieties. Overall, our evaluation suggested the suitability of ORYZA (v3) for simulating rice growth and development of different single‐cropped varieties under different establishment techniques in eastern China.
Time–space coupled learning method for model reduction of distributed parameter systems with encoder‐decoder and RNN
Authors: Qing Xiangyun , Jin Jing , Niu Yugang , Zhao Shuangliang
Published: April 2020

Model reduction of a high‐dimensional distributed parameter system (DPS) reduces the complexity of the system for various applications, from monitoring to model predictive control, while retaining its intrinsic properties. Unfortunately, the assumption of time–space separability usually fails to hold for popular time–space separation model reduction methods because the space and time of the DPS are inherently coupled. In this study, a time–space coupled learning method for a data‐driven model reduction of the DPS is presented. The proposed method has the advantage of preserving the time–space coupling characteristics and increasing the number of degrees of freedom during the model reduction learning process. A novel deep‐learning architecture is presented by combining encoder‐decoder networks with recurrent neural networks. Given a high‐dimensional system without an exact partial differential equation description, the dimension‐reduced model and its temporal dynamics are jointly learned using the collected input and output data. The learned model is then applied to predict the low‐dimensional representations and reconstruct the high‐dimensional outputs. The proposed method was demonstrated on the catalytic rod in a tubular reactor with recycle, the results of which indicate a better modeling accuracy and lower intrinsic dimensionality compared with classical time–space separation model reduction methods.
Constructing Adaptive Photosensitizers via Supramolecular Modification Based on Pillararene Host–Guest Interactions
Authors: Shao Li , Pan Yutong , Hua Bin , Xu Shidang , Yu Guocan , Wang Mengbin , Liu Bin , Huang Feihe
Published: April 2020

In order to promote the development of photodynamic therapy (PDT), undesired side effects like low tumor specificity and the “always‐on” phenomenon should be avoided. An effective solution is to construct an adaptive photosensitizer that can be activated to generate reactive oxygen species (ROS) in the tumor microenvironment. Herein, we design and synthesize a supramolecular switch based on a host–guest complex containing a water‐soluble pillar[5]arene (WP5) and an AIEgen photosensitizer (G). The formation of the host–guest complex WP5⊃G quenches the fluorescence and inhibits ROS generation of G. Benefitting from the pH‐responsiveness of WP5, the binding site between G and WP5 changes in an acidic environment through a shuttle movement. Consequently, fluorescence and ROS generation of the host–guest complex can be switched on at pH 5.0. This work offers a new paradigm for the construction of adaptive photosensitizers by using a supramolecular method.
Influence of core size and capping ligand of gold nanoparticles on the desorption/ionization efficiency of small biomolecules in AP‐SALDI‐MS
Authors: Liu Zhen , Zhang Peng , Pyttlik Andrea , Kraus Tobias , Volmer Dietrich A.
Published: April 2020

Gold nanoparticles (AuNP) are frequently used in surface‐assisted laser desorption/ionization mass spectrometry (SALDI‐MS) for analysis of biomolecules because they exhibit suitable thermal and chemical properties as well as strong surface plasmonic effects. Moreover, the structures of AuNP can be controlled by well‐established synthesis protocols. This was important in the present work, which studied the influence of the nanoparticles’ structures on atmospheric pressure (AP)‐SALDI‐MS performance. A series of AuNP with different core sizes and capping ligands were investigated, to examine the desorption/ionization efficiency (DIE) under AP‐SALDI conditions. The results showed that both the AuNP core size as well as the nature of the surface ligand had a strong influence on DIE. DIE increased with the size of the AuNP and the hydrophobicity of the ligands. Chemical interactions between ligand and analytes also influenced DIE. Moreover, we discovered that removing the organic ligands from the deposited AuNP substrate layer by simple laser irradiation prior to LDI further amplified DIE values. The optimized AuNP were successfully used to analyze a wide arrange of different low molecular weight biomolecules as well as a crude pig brain extract, which readily demonstrated the ability of the technique to detect a wide range of lipid species within highly complex samples.
Preparation and properties study of waterborne polyurethane synthesized by mixing polyester diols and isocyanates
Authors: Meng Lingqiao , Shi Xingzhao , Zhang Ruilong , Yan Long , Liang Zhaopeng , Nie Yijing , Zhou Zhiping , Hao Tongfan
Published: April 2020

In view of environmental protection requirements, it is an inevitable trend for waterborne coatings to replace traditional coatings. Waterborne polyurethane (WPU), a kind of typical resin used in coatings, has become a research hot topic of waterborne coatings because of its advantages, such as non‐polluting, safe and reliable, excellent properties, good compatibility, and easy modification. In this article, solvent‐free WPU is prepared by mixing 4,4′‐dicyclohexylmethane diisocyanate/ isophorone diisocyanate (HMDI/IPDI) and polycarbonate diol/ Polycaprolactone diol (PCDL/PCL). Through the comparison of the properties of the polymer, the best amount of raw materials was determined. Specifically, R = 1.35 (R is NCO/OH ratio), the content of dimethylolpropionic acid (DMPA) is 5.5%, the content of trimethylol propane (TMP) is 2.5%, the mole ratio of HMDI/IPDI is 2:1, the mole ratio of PCDL/PCL is 2:1, and the preeminent WPU shows the excellent thermal stability, the contact angle of 118.04°, the hardness is H. The chemical structures and rough surface morphologies of the WPU films were characterized by FT‐IR, TG, AFM, and SEM, respectively. Therefore, considering the film properties, and the low cost, simple, and green process, this research will offer the possibility of application of this free‐solvent WPU in industrial production and large‐scale application.
Improvement of the processability and thermal stability of poly(vinyl chloride) with 5,6‐diamino‐1,3‐dimethyluracil
Authors: Ye Weihua , Chen Qinghua , Chen Zheng , Wen Zhi , Liao Zhengfu
Published: April 2020

Uracil derivatives are potential nontoxic thermal stabilizers of poly(vinyl chloride) (PVC) and have a better stabilization effect. 5,6‐diamino‐1,3‐dimethyluracil (DDU) was investigated as a thermal stabilizer for PVC. The stabilization effect of DDU was measured by thermogravimetric analysis, thermal aging test, and recording the time of the color change of the Congo red paper (Congo red test). Meanwhile, the processability of PVC stabilized by DDU was investigated through dynamic performance test. The results showed a better stabilizing effect compared with calcium stearate (CaSt2) and zinc stearate (ZnSt2). To explain the stabilization of DDU, the probable mechanism was suggested that DDU absorbed and chemically bonded with hydrogen chloride. Therefore, DDU could be used as a thermal stabilizer of PVC.
A basic ddRADseq two‐enzyme protocol performs well with herbarium and silica‐dried tissues across four genera
Authors: Jordon‐Thaden Ingrid E. , Beck James B. , Rushworth Catherine A. , Windham Michael D. , Diaz Nicolas , Cantley Jason T. , Martine Christopher T. , Rothfels Carl J.
Published: April 2020

Premise

The ability to sequence genome‐scale data from herbarium specimens would allow for the economical development of data sets with broad taxonomic and geographic sampling that would otherwise not be possible. Here, we evaluate the utility of a basic double‐digest restriction site–associated DNA sequencing (ddRADseq) protocol using DNAs from four genera extracted from both silica‐dried and herbarium tissue.

Methods

DNAs from Draba, Boechera, Solidago, and Ilex were processed with a ddRADseq protocol. The effects of DNA degradation, taxon, and specimen age were assessed.

Results

Although taxon, preservation method, and specimen age affected data recovery, large phylogenetically informative data sets were obtained from the majority of samples.

Discussion

These results suggest that herbarium samples can be incorporated into ddRADseq project designs, and that specimen age can be used as a rapid on‐site guide for sample choice. The detailed protocol we provide will allow users to pursue herbarium‐based ddRADseq projects that minimize the expenses associated with fieldwork and sample evaluation.
The History of the Synapse
Authors: Sotelo Constantino
Published: April 2020

Why did I choose this particular topic for my lecture rather than the history of neuroscience or the history of the neuron? Simply because I believe that every disciple has the obligation to pay homage to their mentors once in their lifetime. My formation as a neuroscientist involved three such mentors spanned across three countries. The first was Spain, where I was born, completed my medical studies, and had my first glimpse of neuroscience at the Cajal Institute with Fernando de Castro. It was him who, in 1961, advised me to spend some time abroad, and to that purpose he obtained me a scholarship from the French government, that allowed me to settle in Paris. Once in France I had the good fortune to meet Prof. René Couteaux, another generous mentor, who took care of my stay in the country. Two years later, he made me a proposition to which I could only answer in the affirmative by offering me a research position in France. I got married (the best thing that happened in my life), and spent the next 57 years working on the cerebellum. The third person I want to honor and remember in this presentation is Sanford Louis Palay who was my postdoc professor during the 2 years I worked at Harvard Medical School in Boston. And as it turns out, all three of my mentors have made positive contributions to the history of the synapse. So, without further delay, let us dive in. Anat Rec, 303:1252–1279, 2020. © 2020 American Association for Anatomy
Flickering of the jet‐ejecting symbiotic star MWC 560
Authors: Zamanov R. K. , Boeva S. , Stoyanov K. A. , Latev G. , Spassov B. , Kurtenkov A. , Nikolov G.
Published: April 2020

We analyzed the optical photometric data of short‐term variability (flickering) of the accreting white dwarf in the jet‐ejecting symbiotic star MWC 560. The observations were obtained on 17 nights during the period November 2011 to October 2019. The color‐magnitude diagram shows that the hot component of the system becomes redder as it gets brighter. For the flickering source, we find that it has color 0.14 < B − V < 0.40, temperature in the range 6,300 < Tfl < 11,000 K, and radius 1.2 < Rfl < 18 R⊙. We find a strong correlation (correlation coefficient 0.76, significance <0.001) between B band magnitude and the average radius of the flickering source—as the brightness of the system increases, the size of the flickering source also increases. The estimated temperature is similar to that of the bright spot of cataclysmic variables. In 2019, the flickering was missing, and the B–V color of the hot component became bluer.
Imaging anatomy of the vertebral canal for trans‐sacral hiatus puncture of the lumbar cistern
Authors: Trinh Austin , Hashmi Syed S. , Massoud Tarik F.
Published: April 2020

A standard lumbar puncture may be impossible for many anatomic or technical reasons. Previous accounts of caudal epidural anesthesia and other procedures via the sacral hiatus prompted us to test if image‐guided percutaneous trans‐sacral hiatus access to the lumbosacral subarachnoid cistern would be anatomically feasible. To study vertebral canal morphometry and curvature, we analyzed midsagittal computed tomography‐myelogram images of 40 normal subjects and digitally measured sacral curvatures between S1 to S5 and S2 to S4 using two methods whereby a lower angle signifies a straighter sacrum. We measured midsagittal vertebral canal area, hiatus width, dural sac termination levels, and distance from sacral hiatus to the dural sac tip (needle distance). Subjects were F:M = 25:15, with a mean age of 44.9 years. The two S1–S5 full sacral curvature mean angles were 57.3° and 60.4°. Almost all sacral hiatuses were at S4, and dural sac terminations were at S1–S2. The mean S2–S4 sacral curvature was 25.1°, and the mean needle distance was 57.7 mm. Using two‐way analysis of variance, there were significant sex differences for needle distances (p = .001), and full and limited sacral curvatures (p = .02, and p = .046, respectively). There were no significant linear regression correlations between age and sacral curvature, needle distance, canal area, or hiatus width. Therefore, despite a frequently prominent full sacral curvature, the combination of S1–S2 dural sac termination plus a relatively straight trajectory of the lower vertebral canal between S2 and S4 support the theoretical feasibility of percutaneous trans‐sacral hiatus and vertebral canal access to the lumbosacral cistern using a standard spinal needle.
English for specific purpose through facilitated and nonfacilitated MOOCs: An analysis of the learners' perspectives
Authors: Safdar Muhammad , Yasmin Musarat , Anwar Behzad
Published: April 2020

Massive Open Online Courses (MOOCs) have gained attention from learners and teachers across the globe, but high dropout rate is a matter of concern, which makes it imperative to understand the reasons. From the theoretical perspective that learners learn more effectively through collaborative and socially cohesive communities, this qualitative study is focused to understand how learners experience facilitated and nonfacilitated MOOCs. It attempts to explore learners' perspectives from two different groups of learners learning the same MOOC of English for journalism. One of the groups is facilitated for the first week of the course by instructors through face‐to‐face interactions, whereas the other is not. The perspectives of the learners from both groups regarding their experiences are analyzed through comparative and contrastive thematic analysis of the data collected through participant observation and semistructured interviews of focus groups selected through purposive sampling technique. Though learning the same ESP MOOC, the learners (18–35 in age; all of them university students), register partly similar and largely contrastive learning experiences across the facilitated and nonfacilitated MOOC environments. It is found that the learners, when facilitated, develop a stronger sense of belongingness, accountability, responsibility, peer competition, networking, and solution of issues, which results in retention of the learners. This study foregrounds the effectiveness of hybrid MOOCs, in terms of retention and satisfaction of learners.
Appellate decision in bankruptcy case creates financial risks for higher ed institutions
Authors: Gelpi Aileen
Published: April 2020

In November 2019, the U.S. First Circuit Court of Appeals decided in In re Palladino, No. 17‐1334 (11/12/19, U.S. 1st Circuit Court of Appeals), that a bankruptcy trustee may claw back from a college or university tuition payments by the parents of an adult child if the payments were made within two years of the filing of a bankruptcy petition and the parents were insolvent at that time. The court specifically refused to address whether it would reach the same outcome if the child was a minor at the time the payments were made.
Magnetically driven microfluidics for isolation of circulating tumor cells
Authors: Luo Laan , He Yongqing
Published: April 2020

Circulating tumor cells (CTCs) largely contribute to cancer metastasis and show potential prognostic significance in cancer isolation and detection. Miniaturization has progressed significantly in the last decade which in turn enabled the development of several microfluidic systems. The microfluidic systems offer a controlled microenvironment for studies of fundamental cell biology, resulting in the rapid development of microfluidic isolation of CTCs. Due to the inherent ability of magnets to provide forces at a distance, the technology of CTCs isolation based on the magnetophoresis mechanism has become a routine methodology. This historical review aims to introduce two principles of magnetic isolation and recent techniques, facilitating research in this field and providing alternatives for researchers in their study of magnetic isolation. Researchers intend to promote effective CTC isolation and analysis as well as active development of next‐generation cancer treatment. The first part of this review summarizes the primary principles based on positive and negative magnetophoretic isolation and describes the metrics for isolation performance. The second part presents a detailed overview of the factors that affect the performance of CTC magnetic isolation, including the magnetic field sources, functionalized magnetic nanoparticles, magnetic fluids, and magnetically driven microfluidic systems.
Bridging the Gap: Plant‐Endophyte Interactions as a Roadmap to Understanding Small‐Molecule Communication in Marine Microbiomes
Authors: Samples Robert M. , Balunas Marcy J.
Published: April 2020

Probing the composition of the microbiome and its association with health and disease states is more accessible than ever due to the rise of affordable sequencing technology. Despite advances in our ability to identify members of symbiont communities, untangling the chemical signaling that they use to communicate with host organisms remains challenging. In order to gain a greater mechanistic understanding of how the microbiome impacts health, and how chemical ecology can be leveraged to advance small‐molecule drug discovery from microorganisms, the principals governing communication between host and symbiont must be elucidated. Herein, we review common modes of interkingdom small‐molecule communication in terrestrial and marine environments, describe the differences between these environments, and detail the advantages and disadvantages for studies focused on the marine environment. Finally, we propose the use of plant‐endophyte interactions as a stepping stone to a greater understanding of similar interactions in marine invertebrates, and ultimately in humans.
Evolution of Glucose Dehydrogenase for Cofactor Regeneration in Bioredox Processes with Denaturing Agents
Authors: Qian Wen‐Zhuo , Ou Ling , Li Chun‐Xiu , Pan Jiang , Xu Jian‐He , Chen Qi , Zheng Gao‐Wei
Published: April 2020

Glucose dehydrogenase (GDH) is a general tool for driving nicotinamide (NAD(P)H) regeneration in synthetic biochemistry. An increasing number of synthetic bioreactions are carried out in media containing high amounts of organic cosolvents or hydrophobic substrates/products, which often denature native enzymes, including those for cofactor regeneration. In this work, we attempted to improve the chemical stability of Bacillus megaterium GDH (BmGDHM0) in the presence of large amounts of 1‐phenylethanol by directed evolution. Among the resulting mutants, BmGDHM6 (Q252L/E170K/S100P/K166R/V72I/K137R) exhibited a 9.2‐fold increase in tolerance against 10 % (v/v) 1‐phenylethanol. Moreover, BmGDHM6 was also more stable than BmGDHM0 when exposed to hydrophobic and enzyme‐inactivating compounds such as acetophenone, ethyl 2‐oxo‐4‐phenylbutyrate, and ethyl (R)‐2‐hydroxy‐4‐phenylbutyrate. Coupled with a Candida glabrata carbonyl reductase, BmGDHM6 was successfully used for the asymmetric reduction of deactivating ethyl 2‐oxo‐4‐phenylbutyrate with total turnover number of 1800 for the nicotinamide cofactor, thus making it attractive for commercial application. Overall, the evolution of chemically robust GDH facilitates its wider use as a general tool for NAD(P)H regeneration in biocatalysis.