bluuebunny/crossref_metadata_2025 huggingface dataset:
Time-dependent relaxed magnetohydrodynamics: Inclusion of cross helicity constraint using phase-space action
Authors: Dewar R. L. , Burby J. W. , Qu Z. S. , Sato N. , Hole M. J.
Published: June 2020

A phase-space version of the ideal magnetohydrodynamic (MHD) Lagrangian is derived from first principles and shown to give a relabeling transformation when a cross-helicity constraint is added in Hamilton's Action Principle. A new formulation of time-dependent “relaxed” magnetohydrodynamics is derived using microscopic conservation of mass and macroscopic constraints on total magnetic helicity, cross helicity, and entropy under variations of density, pressure, fluid velocity, and magnetic vector potential. This gives Euler–Lagrange equations consistent with previous work on both ideal and relaxed MHD equilibria with flow, but generalizes the relaxation concept from statics to dynamics. The application of the new dynamical formalism is illustrated for short-wavelength linear waves, and the interface connection conditions for Multiregion Relaxed MHD (MRxMHD) are derived. The issue of whether E+u×B=0 should be a constraint is discussed.
Low-pressure OH radicals reactor generated by dielectric barrier discharge from water vapor
Authors: Wang Li , Deng LunHua , Li Bao , Fang Bo , Zhao WeiXiong , Xu HuaiLiang
Published: June 2020

Hydroxyl (OH) radicals were generated by dielectric barrier discharge (DBD) from water vapor in a multi-pass cell with a volume of 8000 cm3. The cell was filled with the following water vapor at reduced pressure. The absolute OH number density was accurately determined by direct absorption spectroscopy using a tunable laser operating at 2.8 μm. The absolute OH number density was around 1012 molecules/cm3. Helium, methane, ethane, propane, and carbon monoxide were respectively introduced into the multi-pass cell to study their influences on the OH number density. The decay rate of OH number density was directly related to the reaction rates of the added gases. The low-pressure DBD OH multi-pass cell can be used as a reactor to further study the reaction kinetics associated with OH radicals.
High-Q nanobeam cavities on a silicon nitride platform enabled by slow light
Authors: Zhan Jiahao , Jafari Zeinab , Veilleux Sylvain , Dagenais Mario , De Leon Israel
Published: June 2020

Silicon nitride integrated photonic devices benefit from a wide working spectral range covering the visible and near-infrared spectra, which in turn enables important applications in bio-photonics, optical communications, and sensing. High-quality factor optical resonators are essential photonic devices for such applications. However, implementing such resonators on a silicon nitride platform is quite challenging due to the low refractive index contrast attainable with this material. Here, we demonstrate that silicon nitride photonic cavities comprising a slow-light waveguide bounded by mirrors can in principle exhibit quality factors in the order of several millions despite a relatively low refractive index contrast. We show that the energy stored in such a slow-light cavity exhibits a cubic dependence on the cavity length, which can enable extremely large quality factors with modest-length cavities. We present the design and experimental characterization of silicon nitride slow-light nanobeam-type cavities. Two sets of nanobeam cavities were fabricated to experimentally verify the cubic dependence of the Q factor on the cavity length. The highest measured Q factor in our devices is 4.42 × 105, which is limited by fabrication imperfections.
Chiral-anomaly induced large negative magnetoresistance and nontrivial π-Berry phase in half-Heusler compounds RPtBi (R=Tb, Ho, and Er)
Authors: Chen Jie , Li Hang , Ding Bei , Liu Enke , Yao Yuan , Wu Guangheng , Wang Wenhong
Published: June 2020

We report on the observation of a large negative magnetoresistance (MR) with magnitudes of −67%, −45%, and −31% in antiferromagnetic half-Heusler compounds TbPtBi, HoPtBi, and ErPtBi, respectively. It is found that with increasing temperature, the values of the negative MR vary smoothly and persist well above their Neel temperature TN. Besides the negative MR effects, we have further observed a nontrivial Berry phase (∼π) extracted from Shubnikov–de Haas oscillation in HoPtBi. These results together with band structure calculations unambiguously give evidence of the chiral anomaly effect and are valuable for understanding the Weyl fermions in magnetic lanthanide half-Heusler compounds.
Effect of secondary reflector on solar flux intensity and uniformity of a Fresnel concentrator
Authors: Minaeian Ali , Alemrajabi A. , Chavoshi M. , Mostafaeipour A. , Seifi Z.
Published: June 2020

Nowadays, consumption of renewable energies such as solar energies is increasing. Electricity in solar systems is produced using either photovoltaics or concentrated solar power (CSP) systems. Therefore, concentrating technologies are key parts of CSP systems. The lower cost of linear Fresnel collectors makes them attractive for electricity production and thermal energy applications. However, due to partly losing the reflected rays, their optical efficiency is low. By installing a secondary reflector above the absorber tube of Fresnel collectors, lost rays are mostly redirected toward the absorber tube and a higher optical efficiency is achieved. The geometry and configuration of secondary reflectors have an intense influence on the optical efficiency. Therefore, there is a need to determine the most appropriate shape and configuration of secondary reflectors. In this study, four different types and orientations of secondary reflectors including circular, flat, few segmented, and parabolic were investigated and compared optically. All the geometric parameters were optimized for each case individually. To calculate the solar flux intensity and uniformity on the absorber tube, a ray-tracing method was implemented using a mathematical code that was developed based on MATLAB software. All the secondary reflectors were simulated in the code, with variable geometrical parameters. A wide range of geometrical parameters were investigated to obtain the most efficient geometry of every secondary reflector design in flux intensity and flux uniformity in comparison with the other cases. The results showed that few flat segmented collectors increase the flux to 87.9%. In addition, the highest uniformity of solar flux was obtained by using the circular and parabolic secondary reflectors. Considering the manufacturing cost as an important parameter, the flat reflector was the favorable one from the flux quantity point of view. Finally, if all the three criteria, i.e., flux quantity, its distribution, and manufacturing cost, were essential to be considered, the flat reflector might be chosen as the most appropriate secondary reflector.
Refractive index prediction models for polymers using machine learning
Authors: Lightstone Jordan P. , Chen Lihua , Kim Chiho , Batra Rohit , Ramprasad Rampi
Published: June 2020

The refractive index (RI) is an important material property and is necessary for making informed materials selection decisions when optical properties are important. Acquiring accurate empirical measurements of RI is time consuming, and while semi-empirical and computational determination of RI is generally faster than empirical determination, predictions are less accurate. In this work, we utilized experimentally measured RI data of polymers to build a machine learning model capable of making accurate near-instantaneous predictions of RI. The Gaussian process regression model is trained using data of 527 unique polymers. Feature engineering techniques were also used to optimize model performance. This new model is one of the most chemically diverse and accurate RI prediction models to date and improves upon our previous work. We also concluded that the model is capable of providing insights about structure–property relationships important for estimating the RI when designing new polymer backbones.
Electrostatic wave propagation in an array of metallic wires
Authors: Moradi Afshin
Published: June 2020

Propagation of electrostatic waves in an array of parallel infinitely long metallic wires is investigated. General expressions for the dispersion relation and polarization are presented. Existence of electrostatic oscillations is due to the anisotropic property of the system. Similar results can be found for the electrostatic plasma waves propagating at an angle to a static magnetic field in an array of metallic nanospheres.
Iron-doped VSe2 nanosheets for enhanced hydrogen evolution reaction
Authors: Wang Chaolun , Wu Xing , Zhang Xuan , Mu Gang , Li Panlin , Luo Chen , Xu Hejun , Di Zengfeng
Published: June 2020

Alloying is critical for regulating the electron states of layered two-dimensional (2D) materials, which has a significant influence on the physical and chemical properties of 2D materials, such as electrochemical catalysis, magnetism, and the bandgap of semiconductors. Here, we report the alloy of Fe-doped VSe2 with good homogeneity at the atomic level by using a one-step synthesis method. Fe-doped VSe2 presents enhanced hydrogen evolution reaction (HER) performance. It is found that Fe-doped VSe2 shows improved catalytic activity compared to the virgin VSe2, including a lower overpotential and a smaller Tafel slope. The enhanced HER performance indicates a lower Gibbs free energy of the HER process, resulting from the doping-induced regulation of the electron states. Our work presents a facile method to prepare transition metal-doped 2D materials and offers a general way to regulate the catalytic properties of 2D materials for energy conversion applications.
Vibrational properties of LaNiO3 films in the ultrathin regime
Authors: Schober Alexander , Fowlie Jennifer , Guennou Mael , Weber Mads C. , Zhao Hongjian , Íñiguez Jorge , Gibert Marta , Triscone Jean-Marc , Kreisel Jens
Published: June 2020

Collective rotations and tilts of oxygen polyhedra play a crucial role in the physical properties of complex oxides such as magnetism and conductivity. Such rotations can be tuned by preparing thin films in which dimensionality, strain, and interface effects come into play. However, little is known of the tilt and rotational distortions in films a few unit cells thick including the question of if coherent tilt patterns survive at all in this ultrathin limit. Here, a series of films of perovskite LaNiO3 is studied and it is shown that the phonon mode related to oxygen octahedral tilts can be followed by Raman spectroscopy down to a film thickness of three pseudocubic perovskite unit cells (∼1.2 nm). To push the limits of resolution to the ultrathin regime, a statistical analysis method is introduced to separate the Raman signals of the film and substrate. Most interestingly, these analyses reveal a pronounced hardening of the tilt vibrational mode in the thinnest films. A comparison between the experimental results, first principles simulations of the atomic structure, and the standing wave model, which accounts for size effects on the phononic properties, reveals that in the ultrathin regime, the Raman spectra are a hybrid entity of both the bulk and surface phononic behavior. These results showcase Raman spectroscopy as a powerful tool to probe the behavior of perovskite films down to the ultrathin limit.
Interference in between the acts of pre- and postselection
Authors: Rostom A.
Published: June 2020

As an alternative approach for measuring the weak effects associated with the artificial preparation of rare events in quantum metrology, we propose the study of the interference pattern generated by acts of pre- and postselection of a quantum system. An example of two Mach – Zehnder interferometers connected by a cross-Kerr nonlinearity is considered. Postselection of photon states at the output of one of the interferometers and the application of a controlled phase shift in one of its arms induces interference phenomena in the photodetection statistics at the output of the second interferometer. The nonlinearity parameter determines the shift and width of the structures in the interference pattern. The main features of this pattern are studied depending on the magnitude of the Kerr nonlinearity and the number of photons at the input of the interferometers.
Detection of the clock transition in thulium atoms by using repump laser radiation
Authors: Tregubov D.O. , Golovizin A.A. , Fedorova E.S. , Mishin D.A. , Provorchenko D.I. , Khabarova K.Yu. , Sorokin V.N. , Kolachevsky N.N.
Published: June 2020

A population transfer from the upper level of the clock transition in thulium atoms to the ground level is demonstrated by using radiation with a wavelength of 402 nm. The method for detecting the clock transition excitation that is not affected by technical fluctuations of the number of atoms in an optical lattice is investigated. The hyperfine splitting of the |4f12(3F2)5d5/2 6s2; J = 7/2〉 level in the thulium atom is measured to be 1480(9) MHz. The suggested method for population transfer can be applied to both the hyperfine components of the clock transition intended for compensating Zeeman effect in a thulium optical clock.
David Roderick Curtis 1927–2017
Authors: Redman Stephen J. , Porter Robert
Published: June 2020

David Curtis was a pioneer in the identification of excitatory and inhibitory transmitters released at synapses in the central nervous system. He made major contributions to the identification of gamma-amino butyric acid (GABA) and glycine as inhibitory transmitters released at inhibitory synapses. His work laid the foundation for the subsequent acceptance that L-glutamate was the major excitatory transmitter. David’s scientific work led to him receiving many accolades and honours, including Fellowships of the Australian Academy of Sciences, the Royal Society and a Companion of the Order of Australia.
Liquid network connectivity regulates the stability and composition of biomolecular condensates with many components
Authors: Espinosa Jorge R. , Joseph Jerelle A. , Sanchez-Burgos Ignacio , Garaizar Adiran , Frenkel Daan , Collepardo-Guevara Rosana
Published: June 2020

Significance

LLPS plays an important role in the spatiotemporal organization of the numerous molecular constituents of living cells, via formation of biomolecular condensates. Our simulations provide predictive rules governing the stability and composition of multicomponent biomolecular condensates. Biomolecules that increase the molecular connectivity of condensates are present in higher concentrations because connectivity is positively correlated with stability. Greater connectivity within highly multicomponent condensates manifests in higher critical temperatures in the phase diagrams of accessible systems involving just a few components. Hence, composition of highly multicomponent condensates can be predicted from the critical points of reduced-component mixtures. Our findings expand the mechanisms relating phase behavior of multicomponent intracellular mixtures to critical parameters (temperature, pH, salt concentration, etc.) of the constituent biomolecules.
MAML1/2 promote YAP/TAZ nuclear localization and tumorigenesis
Authors: Kim Jiyoung , Kwon Hyeryun , Shin You Keun , Song Gahyeon , Lee Taebok , Kim Youngeun , Jeong Wonyoung , Lee Ukjin , Zhang Xianglan , Nam Gilyeong , Jeung Hei-Cheul , Kim Wantae , Jho Eek-hoon
Published: June 2020

Significance

The Hippo-YAP/TAZ pathway plays pivotal roles in controlling tissue growth, and its abnormal regulation is frequently implicated in a variety of cancers. We have identified MAML1/2 as critical regulators for YAP/TAZ nuclear retention and transcription activities. Clinical analysis with specimens of a human cancer patient and a public cancer database reveals pathological association between MAML expression and YAP signature. Furthermore, our results suggest that the cell density governing YAP/TAZ subcellular localization can also function as an important intrinsic mechanism for miR30c-dependent regulation of MAML1 level. Our findings provide mechanistic insights of YAP/TAZ-dependent growth control pathway and tumorigenesis.
Incrementality and efficiency shape pragmatics across languages
Authors: Rubio-Fernandez Paula , Jara-Ettinger Julian
Published: June 2020

To correctly interpret a message, people must attend to the context in which it was produced. Here we investigate how this process, known as pragmatic reasoning, is guided by two universal forces in human communication: incrementality and efficiency, with speakers of all languages interpreting language incrementally and making the most efficient use of the incoming information. Crucially, however, the interplay between these two forces results in speakers of different languages having different pragmatic information available at each point in processing, including inferences about speaker intentions. In particular, the position of adjectives relative to nouns (e.g., “black lamp” vs. “lamp black”) makes visual context information available in reverse orders. In an eye-tracking study comparing four unrelated languages that have been understudied with regard to language processing (Catalan, Hindi, Hungarian, and Wolof), we show that speakers of languages with an adjective–noun order integrate context by first identifying properties (e.g., color, material, or size), whereas speakers of languages with a noun–adjective order integrate context by first identifying kinds (e.g., lamps or chairs). Most notably, this difference allows listeners of adjective–noun descriptions to infer the speaker’s intention when using an adjective (e.g., “the black…” as implying “not the blue one”) and anticipate the target referent, whereas listeners of noun–adjective descriptions are subject to temporary ambiguity when deriving the same interpretation. We conclude that incrementality and efficiency guide pragmatic reasoning across languages, with different word orders having different pragmatic affordances.
Structural basis for allosteric transitions of a multidomain pentameric ligand-gated ion channel
Authors: Hu Haidai , Howard Rebecca J. , Bastolla Ugo , Lindahl Erik , Delarue Marc
Published: June 2020

Pentameric ligand-gated ion channels (pLGICs) are allosteric receptors that mediate rapid electrochemical signal transduction in the animal nervous system through the opening of an ion pore upon binding of neurotransmitters. Orthologs have been found and characterized in prokaryotes and they display highly similar structure–function relationships to eukaryotic pLGICs; however, they often encode greater architectural diversity involving additional amino-terminal domains (NTDs). Here we report structural, functional, and normal-mode analysis of two conformational states of a multidomain pLGIC, called DeCLIC, from a
Desulfofustis
deltaproteobacterium, including a periplasmic NTD fused to the conventional ligand-binding domain (LBD). X-ray structure determination revealed an NTD consisting of two jelly-roll domains interacting across each subunit interface. Binding of Ca
2+
at the LBD subunit interface was associated with a closed transmembrane pore, with resolved monovalent cations intracellular to the hydrophobic gate. Accordingly, DeCLIC-injected oocytes conducted currents only upon depletion of extracellular Ca
2+
; these were insensitive to quaternary ammonium block. Furthermore, DeCLIC crystallized in the absence of Ca
2+
with a wide-open pore and remodeled periplasmic domains, including increased contacts between the NTD and classic LBD agonist-binding sites. Functional, structural, and dynamical properties of DeCLIC paralleled those of sTeLIC, a pLGIC from another symbiotic prokaryote. Based on these DeCLIC structures, we would reclassify the previous structure of bacterial ELIC (the first high-resolution structure of a pLGIC) as a “locally closed” conformation. Taken together, structures of DeCLIC in multiple conformations illustrate dramatic conformational state transitions and diverse regulatory mechanisms available to ion channels in pLGICs, particularly involving Ca
2+
modulation and periplasmic NTDs.
Airborne bacteria confirm the pristine nature of the Southern Ocean boundary layer
Authors: Uetake Jun , Hill Thomas C. J. , Moore Kathryn A. , DeMott Paul J. , Protat Alain , Kreidenweis Sonia M.
Published: June 2020

Microorganisms are ubiquitous and highly diverse in the atmosphere. Despite the potential impacts of airborne bacteria found in the lower atmosphere over the Southern Ocean (SO) on the ecology of Antarctica and on marine cloud phase, no previous region-wide assessment of bioaerosols over the SO has been reported. We conducted bacterial profiling of boundary layer shipboard aerosol samples obtained during an Austral summer research voyage, spanning 42.8 to 66.5°S. Contrary to findings over global subtropical regions and the Northern Hemisphere, where transport of microorganisms from continents often controls airborne communities, the great majority of the bacteria detected in our samples were marine, based on taxonomy, back trajectories, and source tracking analysis. Further, the beta diversity of airborne bacterial communities varied with latitude and temperature, but not with other meteorological variables. Limited meridional airborne transport restricts southward community dispersal, isolating Antarctica and inhibiting microorganism and nutrient deposition from lower latitudes to these same regions. A consequence and implication for this region’s marine boundary layer and the clouds that overtop it is that it is truly pristine, free from continental and anthropogenic influences, with the ocean as the dominant source controlling low-level concentrations of cloud condensation nuclei and ice nucleating particles.
A molecular tandem cell for efficient solar water splitting
Authors: Wang Degao , Hu Jun , Sherman Benjamin D. , Sheridan Matthew V. , Yan Liang , Dares Christopher J. , Zhu Yong , Li Fei , Huang Qing , You Wei , Meyer Thomas J.
Published: June 2020

Significance

A major challenge for artificial photosynthesis is creating a photoelectrode to split water without an added bias. Here, we demonstrate the value of combining of a dye-sensitized photoelectrosynthesis cell and an organic solar cell in a photoanode for water oxidation. With the two component electrodes, and a counter Pt electrode for H
2
evolution, the electrode becomes part of a combined electrochemical cell for unassisted water splitting, 2H
2
O → O
2
+ 2H
2
. The results described here offer a major improvement in solar-to-hydrogen conversion efficiency (STH%) for a molecularly based solar fuel electrode. The STH% for water splitting was 1.5% for the tandem cell compared to ∼1% for natural photosynthesis.
Pivotal role of the transcriptional co-activator YAP in trophoblast stemness of the developing human placenta
Authors: Meinhardt Gudrun , Haider Sandra , Kunihs Victoria , Saleh Leila , Pollheimer Jürgen , Fiala Christian , Hetey Szabolcs , Feher Zsofia , Szilagyi Andras , Than Nandor Gabor , Knöfler Martin
Published: June 2020

Various pregnancy complications, such as severe forms of preeclampsia or intrauterine growth restriction, are thought to arise from failures in the differentiation of human placental trophoblasts. Progenitors of the latter either develop into invasive extravillous trophoblasts, remodeling the uterine vasculature, or fuse into multinuclear syncytiotrophoblasts transporting oxygen and nutrients to the growing fetus. However, key regulatory factors controlling trophoblast self-renewal and differentiation have been poorly elucidated. Using primary cells, three-dimensional organoids, and CRISPR-Cas9 genome-edited JEG-3 clones, we herein show that YAP, the transcriptional coactivator of the Hippo signaling pathway, promotes maintenance of cytotrophoblast progenitors by different genomic mechanisms. Genetic or chemical manipulation of YAP in these cellular models revealed that it stimulates proliferation and expression of cell cycle regulators and stemness-associated genes, but inhibits cell fusion and production of syncytiotrophoblast (STB)-specific proteins, such as hCG and GDF15. Genome-wide comparisons of primary villous cytotrophoblasts overexpressing constitutively active YAP-5SA with YAP KO cells and syncytializing trophoblasts revealed common target genes involved in trophoblast stemness and differentiation. ChIP-qPCR unraveled that YAP-5SA overexpression increased binding of YAP–TEAD4 complexes to promoters of proliferation-associated genes such as
CCNA
and
CDK6
. Moreover, repressive YAP–TEAD4 complexes containing the histone methyltransferase EZH2 were detected in the genomic regions of the STB-specific
CGB5
and
CGB7
genes. In summary, YAP plays a pivotal role in the maintenance of the human placental trophoblast epithelium. Besides activating stemness factors, it also directly represses genes promoting trophoblast cell fusion.
A Spatiotemporal Trajectory Data Index Based on the Hilbert Curve Code
Authors: Wu YuHao , Cao Xuefeng , An Zipeng
Published: June 2020

Massive trajectory data have been accumulated with the rapid development of global positioning technology and the popularisation of intelligent mobile terminal. However, the generation of massive data does not necessarily lead to the increase in effective data. An index method meeting the efficient management requirements of spatiotemporal trajectory data needs to be designed for the efficient spatiotemporal analysis and calculation of data. This paper proposes a spatiotemporal index method based on the Hilbert curve code to solve this problem. Firstly, the method constructs a multi-scale spatiotemporal grid model covering the whole world by dividing the three-dimensional space composed of time, latitude and longitude. Secondly, the grid cell codes are designed based on the Hilbert curve for hierarchical organisation of the trajectory data. Finally, the corresponding query process based on the code index is proposed in accordance with the different spatiotemporal query requirements of trajectory data. The comparison experiments show that the proposed method is more efficient than the existing spatiotemporal index method and can effectively support the management of massive multi-scale trajectory data.
Research on Urban Building Extraction Method Based on Deep Learning Convolutional Neural Network
Authors: Lv Beiru , Peng Ling , Wu Tong , Chen Ruonan
Published: June 2020

Buildings’ location information is an important basic data for the construction of refined smart city. Using remote sensing images to obtain building information is both high-quality and efficiency. However, urban village building is a very special category in remote sensing image of urban area. The distribution patterns of buildings inside the urban village is quite unique, such as high building density, narrow streets and lanes, concentrated illegal buildings, which brings various high-risk security risks. Therefore, how to use remote sensing technique to detect the structural characteristics and explore the spatial distribution patterns of urban village buildings through massive urban image data is of great significance to both planning and governing urban villages. Traditional remote sensing image building extraction methods have the problems of large workload, low efficiency and slow update, and the buildings in the urban village has complex building types and serious interference of deposits. To tackle the above issues, this paper adopts the deep learning convolutional neural network algorithm which is the advanced method in the field of computer vision, and proposes a building extraction method based on high-resolution remote sensing images. In this paper, Mask R-CNN, an instance segmentation method, is used to extract urban village buildings. After trained on 678 samples, this method reached 66% mAP on test dataset. In addition, spatial distribution patterns of the research area are analysed based on the detection result. The spatial analyzation results show that buildings in the research area are with small average building area and large building density and do not compliance with regulations of People’s Republic of China on the Planning and Design Standards for Urban Residential Areas.
Sensitivity Analysis of Vegetation Coverage to Soil Loss Rate in Red Soil Region of South China
Authors: Yifeng Liu , Xiaoqin Wang , Miaojin Chen
Published: June 2020

Vegetation is an important basic component of terrestrial ecosystem and one of the most sensitive factors affecting soil erosion. How to analyse the quantitative relationship between fractional vegetation cover (FVC) and soil erosion and determine the sensitive coverage of erosion is of great significance for guiding government departments to implement soil and water conservation policies. In this paper, through the variable-controlling mothed, the forest land, grassland and bare land in Changting County, a typical red soil region in southern China, were used as experimental areas to study the sensitivity of FVC change to soil erosion. The soil erosion amount was calculated by RUSLE model, and soil loss rate (rsl) were used to characterize soil erosion. The results show that when FVC changes from 0 to 0.8, the fitting curves rsl are in accordance with the logistic model distributions, with a high coefficient of determination R2, and the sensitivity of rsl is less sensitive in the range of 0∼0.05, it is most sensitive when FVC reaches a certain level, and there is basically no sensitivity when it reaches 0.7 or above; the fitting curves of rsl at different slope levels are similar to their overall distribution, which are consistent with the logistic models, and R2 is above 0.99, the curves of rsl at each slope level are different in the same FVC interval, for areas with poor vegetation coverage (0∼0.2) and high slope (>25°), the curve is less sensitive to terrain; rsl generally has higher sensitivity in the range of 0.2∼0.6 coverage; in areas above 0.6, the sensitivity decreases to zero.
3D printed oxidized alginate-gelatin bioink provides guidance for C2C12 muscle precursor cell orientation and differentiation via shear stress during bioprinting
Authors: Distler Thomas , Solisito Aditya A , Schneidereit Dominik , Friedrich Oliver , Detsch Rainer , Boccaccini Aldo R
Published: June 2020

Biofabrication can be a tool to three-dimensionally (3D) print muscle cells embedded inside hydrogel biomaterials, ultimately aiming to mimic the complexity of the native muscle tissue and to create in-vitro muscle analogues for advanced repair therapies and drug testing. However, to 3D print muscle analogues of high cell alignment and synchronous contraction, the effect of biofabrication process parameters on myoblast growth has to be understood. A suitable biomaterial matrix is required to provide 3D printability as well as matrix degradation to create space for cell proliferation, matrix remodelling capacity, and cell differentiation. We demonstrate that by the proper selection of nozzle size and extrusion pressure, the shear stress during extrusion-bioprinting of mouse myoblast cells (C2C12) can achieve cell orientation when using oxidized alginate-gelatin (ADA-GEL) hydrogel bionk. The cells grow in the direction of printing, migrate to the hydrogel surface over time, and differentiate into ordered myotube segments in areas of high cell density. Together, our results show that ADA-GEL hydrogel can be a simple and cost-efficient biodegradable bioink that allows the successful 3D bioprinting and cultivation of C2C12 cells in-vitro to study muscle engineering.
Improving alginate printability for biofabrication: establishment of a universal and homogeneous pre-crosslinking technique
Authors: Hazur Jonas , Detsch Rainer , Karakaya Emine , Kaschta Joachim , Teßmar Jörg , Schneidereit Dominik , Friedrich Oliver , Schubert Dirk W , Boccaccini Aldo R
Published: June 2020

Many different biofabrication approaches as well as a variety of bioinks have been developed by researchers working in the field of tissue engineering. A main challenge for bioinks often remains the difficulty to achieve shape fidelity after printing. In order to overcome this issue, a homogeneous pre-crosslinking technique, which is universally applicable to all alginate-based materials, was developed. In this study, the Young’s Modulus after post-crosslinking of selected hydrogels, as well as the chemical characterization of alginate in terms of M/G ratio and molecular weight, were determined. With our technique it was possible to markedly enhance the printability of a 2% (w/v) alginate solution, without using a higher polymer content, fillers or support structures. 3D porous scaffolds with a height of around 5 mm were printed. Furthermore, the rheological behavior of different pre-crosslinking degrees was studied. Shear forces on cells as well as the flow profile of the bioink inside the printing nozzle during the process were estimated. A high cell viability of printed NIH/3T3 cells embedded in the novel bioink of more than 85% over a time period of two weeks could be observed.
Multi-layer lithography using focal plane changing for SU-8 microstructures
Authors: Chen Qiming , Zhou Jinyun , Zheng Qi , Hu Yiming
Published: June 2020

In this paper, we report on a type of SU-8 microstructure with vertical sidewalls used for polydimethydiloxane (PDMS) microchannels. Multi-layer lithography using focal plane changing approach is proposed to expose the SU-8 photoresist based on a digital micromirror device (DMD) maskless lithography system. We used a light-emitting diode source with a wavelength of 405 nm. The thickness of the SU-8 is divided into multi-layers according to the depth of focus. Each layer corresponds to a depth of focus, and then, a virtual mask is designed for the layer. Finally, each layer is exposed to changes in the focal plane. The results indicate that the actual profile of the SU-8 mold shows good agreement with the design profile without any T-profiles. Additionally, there is better linewidth in the proposed method compared with multi-exposure by a single fixed focal plane. The PDMS microchannels result also demonstrate the stability of the SU-8 mold.
Investigating the mechanical behavior of hydroxyapatite-reduced graphene oxide nanocomposite under different loading rates
Authors: Nosrati Hassan , Sarraf-Mamoory Rasoul , Le Dang Quang Svend , Ahmadi Amir Hossein , Canillas Perez Maria , Bünger Cody Eric
Published: June 2020

In this study, the hydroxyapatite (HA)-reduced graphene oxide (rGO) nanocomposite was investigated for its mechanical properties. The nanocomposite used in this study was made in two stages. The HA-rGO powders were first synthesized by hydrogen gas injected hydrothermal method, and then consolidated by spark plasma sintering. HA-rGO nanocomposite was subjected to Vickers indentation experiments with different loading rates. Various analyzes have been used in this study, including x-rays diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, fast fourier transform, and inverse fast fourier transform. The findings of this study showed that the HA in this nanocomposite was reinforced with rGO sheets coated with HA. As the loading rate increased, the slope of the curves in the elastic region was increased, indicating that the elastic modulus was increased. Also, the contact depth at higher loading rates was increased. Plastic deformation was higher at higher loading rates and the hardness had increased. As the loading rate increased from 300 mN to 1 N, the hardness and elastic modulus increased with more slope than when the loading rate changed from 1 N to 2 N. The presence of rGO sheets had partially controlled the HA brittleness.
Minor Literature
Authors: El Moncef Salah
Published: June 2020

As they developed their theory of minor literature in the mid-1970s, Gilles Deleuze and Félix Guattari created more than a concept of literary criticism. Articulating minor thought as a theoretical mode of engagement that impels the minor author to evolve into an agent of transformative experimentation and collective awareness, Deleuze and Guattari’s Kafka theorizes this radically reassessed function of the writer in terms of marginal subjectivity—the subject position of an “immigrant” whose task is to craft an innovative “minor language” on the margin of the “major language” of mainstream society, along with projecting new visions of diverse collectivities within the traditional nation-state that challenge and transform its identitarian definitions of gender, class, ethnic, cultural, and linguistic “standards.” It is around this paradigmatic conception of the minor subject as perpetual immigrant and “nomadic” other that Gloria Anzaldúa and Kathy Acker develop their own variations on the Deleuze–Guattarian minor mode: narrative presentations of the deterritorialized subjects that inhabit the pluralistic Borderlands (Borderlands/La Frontera) and the transnational Empire (Empire of the Senseless). Seeking to renew standard English in order to develop within it innovative esthetic, social, and global visions, the two authors confront their readers with the experiences of minority existence, endeavoring to develop, through the prototypical narrative agents at the center of their works, emergent modalities of hybrid transnational subjectivity—a new post-statist subject, in sum. By depicting their central narrative agents as transnational nomads confronted with the limitations and potentialities of their minority status, Acker and Anzaldúa engage in highly complex social and ontological explorations of the plural inflections of the minor subject as they are expressed in the hybrid idioms he or she adopts and the sociocultural choices they make. In presenting the reader with narrative agents who dwell on the margin of the general social norm, both authors posit the minor subject as the embodiment of a “borderline” existence in which the Borderlands and the Empire are not conceived as geopolitical spaces but rather as conceptual sites of social experimentation; collective realms governed by a universal desire to supersede all borders, imaginary or geopolitical. A central conclusion emerges from Acker’s and Anzaldúa’s visions of the transnational, hybrid subject and collectivity: the deterritorialized movements of groups and individuals envisioned by both authors are at the heart of the postmodern nomad’s aspirations—an inherently transnational quest for self-fulfillment through which she or he seeks unfamiliar horizons as she or he experiments with various elements of hybridity, allowing him/herself to apprehend the existential conditions of his/her exile as affirmative instruments toward asserting the global in relation to the local and the transnational in relation to the national.
Everyday
Authors: Galperin William
Published: June 2020

The central issue surrounding the “everyday” in relation to literature and to literary study is etymological: a distinction between the “everyday,” a Romantic-period neologism that names both a site of interest and a representational alternative to both the probable and the fantastic; and “everydayness,” a mid-19th-century coinage, reflecting developments particular to urbanization, industrialization, and the rise of capital. This distinction has largely vanished, reflecting the influence of social science, and theory on the humanities and the flight in general from phenomenology. Nevertheless, as the first discourse actually to register the uncanniness of the everyday, literature provides an approach to everyday life that is not only in contrast to the limitations and routines linked to everydayness but also a reminder of possibilities and enchantments that are always close at hand. Although Maurice Blanchot’s axiom that “the everyday is never what we see a first time, but only see again” is as applicable to “everyday life studies” as it is to literature and to related theories of perception, there are fundamental differences. From the perspective of the human sciences and social theory, this discovery is recursive: “the everyday” proceeds from something that “escapes”—which, like ideology, is never quite seen—to something suddenly visible or seen again but with no alteration apart from being retrieved and corralled as a condition of being understood and in many cases lamented. In literature, the escape is ongoing. A parallel world of which we are unaware, or unmindful, becomes visible as if for the first time, but as a condition of remaining missable and always discoverable.
Queer
Authors: González Octavio , Nordgren Todd G.
Published: June 2020

The definitional limits of the term queer have been under conceptual, political, and ethical dispute since its reclamation from its pejorative meaning during the early AIDS crisis of the 1980s and early 1990s. Reflecting activist recuperation, queer became a means to inspire and propel a coalitional politics oriented toward nonconformity and anti-normativity among diverse sexualities and across divisions of gender. Concomitantly, queer theory arose in academia as a way to expand upon and break what some scholars saw as the restrictive disciplinary boundaries of gay and lesbian studies, which were explicitly grounded in post–Stonewall identity politics. The term’s radical potential derives in part from its grammatical fluidity, as it operates as noun, adjective, and verb—combining action, identification, and effect into a single word. In the late 1990s and early 2000s, queer of color critique drew upon a different genealogy, beyond the postmodern rupture inaugurated by Michel Foucault’s work on sexuality and “biopower,” by foregrounding black and women of color feminisms, critical race studies, and postcolonial studies in order to analyze the intersections of race, nationality, coloniality, class, sex, and gender with a Foucauldian understanding of sexuality as a privileged mode of modern power– knowledge. Queer of color critique inspired and was mirrored in investigations of the analytic boundaries of the term, often defined as a binary distinction between a minoritizing and universalizing definition of queer.
American Literature in Japanese Shojo Comics
Authors: Ogushi Hisayo
Published: June 2020

In the Meiji era, the modernization of Japan was achieved through the process of the westernization of political, military, and educational systems. Accordingly, the Japanese willingly acquired and learned Western thought by translating literary resources for Japanese readers: the works of writers such as Ralph Waldo Emerson, Edgar Allan Poe, and Nathaniel Hawthorne were frequently translated and introduced at this time. Concurrently, Japanese girls belonging to the urban middle class began to form their own institutionalized culture called shojo, through which they could communicate their interests in literature or art, and/or share aspects of their ordinary school lives. Shojo culture was supported by newly founded magazines targeting schoolgirls with names like Shojo Sekai, Shojo-kai, Shojo-no-tomo, and Jogaku Zasshi. In Japanese shojo, articles on American women and translated literary pieces written by American and European authors, including Frances Hodgson Burnett, were popular. The work of female American writers like Harriet Beecher Stowe, Louisa May Alcott, and Jean Webster was also translated as juvenile literature for Japanese children. Thus, American culture and literature significantly influenced the Japanese shojo culture. Nobuko Yoshiya, a well-known Japanese author of so-called girls’ novels, stated that she followed Western female writers such as Alcott, Burnett, and George Eliot. The Japanese translations of American literature decreased considerably during World War II. After the war, this literary corpus was rediscovered and was widely translated for Japanese audiences under the supervision of the General Headquarters (GHQ) or the Supreme Commander for the Allied Powers (SCAP). In addition to novels for girls, comics for young female readers (shojo manga) also aroused readers’ interest and became immensely popular. Some manga writers depicted Western settings in their narratives and innumerable “American girls” whose exotic and fashionable aura fascinated Japanese girls. These made-in-Japan “American girls” primarily represented the concept of liberty, autonomy, and abundance: qualities desired by Japanese schoolgirls. At the end of the 20th century, however, the representation of America in the genre of shojo manga gradually became more realistic and less enraptured.
The Single European Act
Authors: Dinan Desmond
Published: June 2020

The Single European Act (SEA) of 1986 was the first major reform of the founding treaties of the three original European Communities, the forerunners of the European Union (EU). The main purpose of the SEA was to facilitate implementation of the Single Market Program by the end of 1992, notably by making it possible for national governments to enact the necessary legislation in the Council of Ministers by means of qualified-majority voting (QMV). To complement the shift of decision-making from unanimity to QMV, the SEA also increased the legislative authority of the European Parliament by introducing the cooperation procedure. This was intended to help close the EC’s perceived democratic deficit, or at least to prevent it from widening. The SEA included changes in other policy areas as well as the single market, such as cohesion policy, environmental policy, research and technology policy, and intergovernmental cooperation on foreign policy (European Political Cooperation). The SEA, and the Single Market Program with which it is closely associated, became synonymous with the acceleration of European integration in the late 1980s. Procedurally and substantively, the SEA set a precedent for other, far-reaching treaty reforms, especially the Maastricht Treaty of 1992. Jacques Delors, who became commission president in 1985, is widely credited with having engineered the SEA. The leaders of France, Germany, and the United Kingdom may have played a more important role, especially as the SEA emerged out of a complicated intergovernmental conference, which culminated in a meeting of the European Council in December 1985. From the perspective of more than three decades later, with the EU facing serious setbacks, the SEA looks like a shining light in the history of European integration.
HIV/AIDS Politics and Policy in U.S. States and Localities
Authors: Siplon Patricia
Published: June 2020

From the earliest days of its recognition in the United States, the condition that came to be known as acquired immunodeficiency syndrome (AIDS) has been associated with the gay community. In fact, when the U.S. Centers for Disease Control and Prevention (CDC) first made written notice of the syndrome in 1981, the acronym GRID (gay-related immune disease) was commonly, although not officially, used to describe it. In the five years that followed, the causal agent, human immunodeficiency virus (HIV), was discovered, specific demographic groups were identified as at heightened risk of infection, and transmission routes—including sexual activity, intravenous drug use, and transfusion of blood and blood products—were determined.

Identification of HIV with the gay community as a major risk group had important ramifications for prevention and treatment policy, as the community mobilized a rights-based approach that advocated harm reduction over abstinence and access and affordability of treatment over the interests of the private market. These concepts carried into later debates as the world recognized the global severity of HIV and grappled for the first time ever with a goal of universal treatment access in the world’s poorest countries where the pandemic is most severe. Identification of HIV with values, conceptual structures, leadership, and mobilization drawn from the gay community also had ramifications on the social and political contexts of AIDS treatment and prevention globally, as governments and cultures that had ignored or demonized their gay populations have increased their interactions with them as “risk groups” and as political actors. Despite the remarkable inroads made into accessibility of treatment, the world remains without a vaccine, a cure, or the political will to fully implement universal treatment access, which means that eradication of the global pandemic remains elusive.