bluuebunny/crossref_metadata_2025 huggingface dataset:
Cutoff manipulation of anisotropic reactance lining in circular waveguides
Authors: Luo Zhangjie , Cui Tie Jun , Ma Hui Feng
Published: December 2018

The control of cutoffs is of great interest in designs of circular waveguides. In this paper, this topic is investigated for pure transverse-electric (TE) and transverse-magnetic (TM) modes by taking advantage of anisotropic reactance lining loadings. It is found that the cutoffs of TE and TM modes are determined by the reactance in the azimuthal and axial directions, respectively. When the reactance values are positive, the cutoff frequencies are lower than those of a normal conducting waveguide with the same cross-section. However, in contrast to the claim made in the previous literature that the negative reactance values caused the same reducing effect on the cutoffs as the positive values did, the cutoffs are found to be increased by the negative reactances. The theoretical results are validated by the simulations using commercial software, where a delicate model with an approximate curved anisotropic impedance boundary is proposed for the first time. By lowering the TE cutoffs and raising the TM ones, some intriguing applications, such as single-mode bandwidth extension and degenerate mode avoidance, are predicted, which would pave a way for designs of novel waveguide devices.
Compositional Variations in the Vicinity of the Lunar Crust‐Mantle Interface From Moon Mineralogy Mapper Data
Authors: Martinot M. , Flahaut J. , Besse S. , Quantin‐Nataf C. , van Westrenen W.
Published: December 2018

Moon Mineralogy Mapper spectroscopic data were used to investigate the mineralogy of a selection of impact craters' central peaks or peak rings, in order to characterize the lunar crust‐mantle interface, and assess its lateral and vertical heterogeneity. The depth of origin of the craters' central peaks or peak rings was calculated using empirical equations, and compared to Gravity Recovery and Interior Laboratory crustal thickness models to select craters tapping within +10/−20 km of the crust‐mantle interface. Our results show that plagioclase is widely detected, including in craters allegedly sampling lower crustal to mantle material, except in central peaks where Low‐Calcium Pyroxene was detected. Olivine detections are scarce, and identified in material assumed to be derived from both above and below the crust‐mantle interface. Mineralogical detections in central peaks show that there is an evolution of the pyroxene composition with depth, that may correspond to the transition from the crust to the mantle. The correlation between High‐Calcium Pyroxene and some pyroxene‐dominated mixture spectra with the location of maria and cryptomaria hints at the existence of lateral heterogeneities as deep as the crust‐mantle interface.
Geomorphic Evolution of a Gravel‐Bed River Under Sediment‐Starved Versus Sediment‐Rich Conditions: River Response to the World's Largest Dam Removal
Authors: East A. E. , Logan J. B. , Mastin M. C. , Ritchie A. C. , Bountry J. A. , Magirl C. S. , Sankey J. B.
Published: December 2018

Understanding river response to sediment pulses is a fundamental problem in geomorphic process studies, with myriad implications for river management. However, because large sediment pulses are rare and usually unanticipated, they are seldom studied at field scale. We examine fluvial response to a massive (~20 Mt) sediment pulse released by the largest dam removal globally, on the Elwha River, Washington, United States, in an 11‐year before‐after/control‐impact study of channel morphology and grain size. We test the hypothesis that for a given flow magnitude, greater geomorphic change occurs under sediment‐rich conditions than under sediment‐starved conditions. Channel response to flow forcing was significantly different during the sediment‐pulse peak, 1–2 years after dam removal began, than earlier or later. During peak sediment supply our hypothesis was supported; major geomorphic change occurred under low flows and unit stream power ≤60 W/m2. However, by 4–6 years after dam removal began, rates of geomorphic change and sensitivity to stream power had decreased substantially such that our hypothesis was no longer unequivocally supported. These findings are consistent with a two‐phase conceptual model of dam‐removal response, involving a transport‐limited state followed by a more supply‐limited state. From comparisons with other dam removals and natural sediment pulses, we infer that the longevity of sediment‐pulse signals in gravel‐bed rivers depends upon gradient, river discharge, valley morphology, and sediment grain size. Stream power associated with substantial geomorphic change varies with sediment supply, such that assigning a general threshold stream power to gravel‐bed rivers may be untenable.
Resistance Is Not Futile: Grain Resistance Controls on Observed Critical Shields Stress Variations
Authors: Yager Elowyn M. , Schmeeckle Mark W. , Badoux Alexandre
Published: December 2018

Estimates of the onset of sediment motion are integral for flood protection and river management but are often highly inaccurate. The critical shear stress (τ*c) for grain entrainment is often assumed constant, but measured values can vary by almost an order of magnitude between rivers. Such variations are typically explained by differences in measurement methodology, grain size distributions, or flow hydraulics, whereas grain resistance to motion is largely assumed to be constant. We demonstrate that grain resistance varies strongly with the bed structure, which is encapsulated by the particle height above surrounding sediment (protrusion, p) and intergranular friction (ϕf). We incorporate these parameters into a novel theory that correctly predicts resisting forces estimated in the laboratory, field, and a numerical model. Our theory challenges existing models, which significantly overestimate bed mobility. In our theory, small changes in p and ϕf can induce large changes in τ*c without needing to invoke variations in measurement methods or grain size. A data compilation also reveals that scatter in empirical values of τ*c can be partly explained by differences in p between rivers. Therefore, spatial and temporal variations in bed structure can partly explain the deviation of τ*c from an assumed constant value. Given that bed structure is known to vary with applied shear stresses and upstream sediment supply, we conclude that a constant τ*c is unlikely. Values of τ*c are not interchangeable between streams, or even through time in a given stream, because they are encoded with the channel history.
Occurrence and Origin of Methane Entrapped in Sediments and Rocks of a Calcareous, Alpine Glacial Catchment
Authors: Zhu Biqing , Henneberger Ruth , Weissert Helmut , Zeyer Josef , Schroth Martin H.
Published: December 2018

Glacial ecosystems are an important indicator of climate change, and dynamics of the greenhouse gas methane (CH4) in these systems has become a major research topic of late. We investigated occurrence and origin of recently discovered, sediment‐entrapped CH4 within the Wildstrubel glacial catchment (Switzerland) using geochemical analyses on gas extracted from sediments and rocks, including gas content and CH4 stable isotope measurements, and computation of gas wetness (ratio of CH4 to ethane and propane). We also examined the potential occurrence of microbial CH4 production in subglacial, supraglacial, and glacier forefield sediments based on molecular analyses targeting mcrA (a marker gene for microbial CH4 production) and based on observed CH4 production during laboratory incubation experiments. Substantial amounts of entrapped CH4 were detected in all sediment (65.7 ± 28.6 μg CH4/g) and most rock samples (up to 145.5 μg CH4/g). Similar gas wetness (0.7–126.7) and CH4 stable isotope values (δ13CCH4: −26.9‰ to −31.2‰, δDCH4: −118.5‰ to −158.6‰) in sediment and rock samples provided strong evidence that entrapped CH4 was of common, thermogenic origin. Molecular analyses (up to ~105 mcrA gene copies per gram) and laboratory incubation experiments (production rates up to 1.55 μg CH4 g−1 day−1) provided evidence for local hot spots of viable methanogens in waterlogged, glacier forefield sediments but not in subglacial sediments. Nonetheless, microbial CH4 production appeared to be only of minor importance at our field site, as indicated by results of our geochemical analyses. Our findings illustrate the crucial importance of appropriate geochemical analyses to provide solid evidence on the origin of CH4 in glacial systems.
Observation of Short‐Period Ionospheric Disturbances Using a Portable Digital Ionosonde at Sanya
Authors: Lan Jiaping , Ning Baiqi , Li Guozhu , Zhu Zhengping , Hu Lianhuan , Sun Wenjie
Published: December 2018

A number of ionosondes have been operated in China to detect ionospheric disturbances for many years. These ionosondes, however, are not very suitable for the short‐period (<15 min) disturbances due to their poor time resolutions (>5 min). During recent years, the Institute of Geology and Geophysics, Chinese Academy of Sciences, together with the South Central University for Nationalities has been developing a portable digital ionosonde (PDI) equipped with the capability to detect and characterize small‐scale/short‐period ionospheric disturbances and to be quickly assembled and set up at temporary field stations for low‐latitude campaign coordinated observations. The PDI uses a set of technologies (e.g., code multiplexing and antenna/transmitter matching) that allow it to obtain quality Doppler ionograms at a good time resolution with small transmitting antennas. A preliminary analysis of observations by the PDI at Sanya (18.3°N, 109.6°E) shows the presence of ionospheric disturbances with periods ranging between several and tens of minutes. Interestingly, the disturbances (with different periods) were found to simultaneously occur at different F region altitudes, for example, with periods of ~5 and 20 min below and above ~180 km, respectively. The absence of shorter‐period disturbance at higher altitude is consistent with acoustic gravity waves through the region with intrinsic periods above the Brunt‐Väisälä period. The short‐period disturbances observed in F region bottomside are not evident in total electron content. The results demonstrate the capability of PDI to detect ionospheric disturbances with temporal scales down to a few minutes in routine ionogram mode. Future prospects of PDI are outlined.
Whole genome MBD-seq and RRBS analyses reveal that hypermethylation of gastrointestinal hormone receptors is associated with gastric carcinogenesis
Authors: Kim Hee-Jin , Kang Tae-Wook , Haam Keeok , Kim Mirang , Kim Seon-Kyu , Kim Seon-Young , Lee Sang-Il , Song Kyu-Sang , Jeong Hyun-Yong , Kim Yong Sung
Published: December 2018

DNA methylation is a regulatory mechanism in epigenetics that is frequently altered during human carcinogenesis. To detect critical methylation events associated with gastric cancer (GC), we compared three DNA methylomes from gastric mucosa (GM), intestinal metaplasia (IM), and gastric tumor (GT) cells that were microscopically dissected from an intestinal-type early gastric cancer (EGC) using methylated DNA binding domain sequencing (MBD-seq) and reduced representation bisulfite sequencing (RRBS) analysis. In this study, we focused on differentially methylated promoters (DMPs) that could be directly associated with gene expression. We detected 2,761 and 677 DMPs between the GT and GM by MBD-seq and RRBS, respectively, and for a total of 3,035 DMPs. Then, 514 (17%) of all DMPs were detected in the IM genome, which is a precancer of GC, supporting that some DMPs might represent an early event in gastric carcinogenesis. A pathway analysis of all DMPs demonstrated that 59 G protein-coupled receptor (GPCR) genes linked to the hypermethylated DMPs were significantly enriched in a neuroactive ligand–receptor interaction pathway. Furthermore, among the 59 GPCRs, six GI hormone receptor genes (NPY1R, PPYR1, PTGDR, PTGER2, PTGER3, and SSTR2) that play an inhibitory role in the secretion of gastrin or gastric acid were selected and validated as potential biomarkers for the diagnosis or prognosis of GC patients in two cohorts. These data suggest that the loss of function of gastrointestinal (GI) hormone receptors by promoter methylation may lead to gastric carcinogenesis because gastrin and gastric acid have been known to play a role in cell differentiation and carcinogenesis in the GI tract.
Neuronal photoactivation through second-harmonic near-infrared absorption by gold nanoparticles
Authors: de Boer Wieteke D. A. M. , Hirtz Jan J. , Capretti Antonio , Gregorkiewicz Tom , Izquierdo-Serra Mercè , Han Shuting , Dupre Christophe , Shymkiv Yuriy , Yuste Rafael
Published: December 2018

Optical activation of neurons requires genetic manipulation or the use of chemical photoactivators with undesirable side effects. As a solution to these disadvantages, here, we demonstrate optically evoked neuronal activity in mouse cortical neurons in acute slices and in vivo by nonlinear excitation of gold nanoparticles. In addition, we use this approach to stimulate individual epitheliomuscular cells and evoke body contractions in Hydra vulgaris. To achieve this, we use a low-power pulsed near-infrared excitation at the double-wavelength of the plasmon resonance of gold nanoparticles, which enables optical sectioning and allows for high spatial precision and large penetration depth. The effect is explained by second-harmonic Mie scattering, demonstrating light absorption by a second-order nonlinear process, which enables photothermal stimulation of the cells. Our approach also minimizes photodamage, demonstrating a major advancement towards precise and harmless photoactivation for neuroscience and human therapeutics.
Sharpening emitter localization in front of a tuned mirror
Authors: Heil Hannah S. , Schreiber Benjamin , Götz Ralph , Emmerling Monika , Dabauvalle Marie-Christine , Krohne Georg , Höfling Sven , Kamp Martin , Sauer Markus , Heinze Katrin G.
Published: December 2018

Single-molecule localization microscopy (SMLM) aims for maximized precision and a high signal-to-noise ratio1. Both features can be provided by placing the emitter in front of a metal-dielectric nanocoating that acts as a tuned mirror2–4. Here, we demonstrate that a higher photon yield at a lower background on biocompatible metal-dielectric nanocoatings substantially improves SMLM performance and increases the localization precision by up to a factor of two. The resolution improvement relies solely on easy-to-fabricate nanocoatings on standard glass coverslips and is spectrally and spatially tunable by the layer design and wavelength, as experimentally demonstrated for dual-color SMLM in cells.
Magnetic field sensors using arrays of electrospun magnetoelectric Janus nanowires
Authors: Bauer Matthew J. , Wen Xiao , Tiwari Prabal , Arnold David P. , Andrew Jennifer S.
Published: December 2018

The fabrication and characterization of the first magnetoelectric sensors utilizing arrays of Janus magnetoelectric composite nanowires composed of barium titanate and cobalt ferrite are presented. By utilizing magnetoelectric nanowires suspended across electrodes above the substrate, substrate clamping is reduced when compared to layered thin-film architectures; this results in enhanced magnetoelectric coupling. Janus magnetoelectric nanowires are fabricated by sol–gel electrospinning, and their length is controlled through the electrospinning and calcination conditions. Using a directed nanomanufacturing approach, the nanowires are then assembled onto pre-patterned metal electrodes on a silicon substrate using dielectrophoresis. Using this process, functional magnetic field sensors are formed by connecting many nanowires in parallel. The observed magnetic field sensitivity from the parallel array of nanowires is 0.514 ± .027 mV Oe−1 at 1 kHz, which translates to a magnetoelectric coefficient of 514 ± 27 mV cm−1 Oe−1.
Integrative system biology analyses of CRISPR-edited iPSC-derived neurons and human brains reveal deficiencies of presynaptic signaling in FTLD and PSP
Authors: Jiang Shan , Wen Natalie , Li Zeran , Dube Umber , Del Aguila Jorge , Budde John , Martinez Rita , Hsu Simon , Fernandez Maria V. , Cairns Nigel J. ,   Dominantly Inherited Alzheimer Network (DIAN),   International FTD-Genomics Consortium (IFGC), Harari Oscar , Cruchaga Carlos , Karch Celeste M.
Published: December 2018

Mutations in the microtubule-associated protein tau (MAPT) gene cause autosomal dominant frontotemporal lobar degeneration with tau inclusions (FTLD-tau).MAPTp.R406W carriers present clinically with progressive memory loss and neuropathologically with neuronal and glial tauopathy. However, the pathogenic events triggered by the expression of the mutant tau protein remain poorly understood. To identify the genes and pathways that are dysregulated in FTLD-tau, we performed transcriptomic analyses in induced pluripotent stem cell (iPSC)–derived neurons carryingMAPTp.R406W and CRISPR/Cas9-corrected isogenic controls. We found that the expression of theMAPTp.R406W mutation was sufficient to create a significantly different transcriptomic profile compared with that of the isogeneic controls and to cause the differential expression of 328 genes. Sixty-one of these genes were also differentially expressed in the same direction betweenMAPTp.R406W carriers and pathology-free human control brains. We found that genes differentially expressed in the stem cell models and human brains were enriched for pathways involving gamma-aminobutyric acid (GABA) receptors and pre-synaptic function. The expression of GABA receptor genes, includingGABRB2andGABRG2, were consistently reduced in iPSC-derived neurons and brains fromMAPTp.R406W carriers. Interestingly, we found that GABA receptor genes, includingGABRB2andGABRG2, are significantly lower in symptomatic mouse models of tauopathy, as well as in brains with progressive supranuclear palsy. Genome wide association analyses reveal that common variants withinGABRB2are associated with increased risk for frontotemporal dementia (P < 1 × 10−3). Thus, our systems biology approach, which leverages molecular data from stem cells, animal models, and human brain tissue can reveal novel disease mechanisms. Here, we demonstrate thatMAPTp.R406W is sufficient to induce changes in GABA-mediated signaling and synaptic function, which may contribute to the pathogenesis of FTLD-tau and other primary tauopathies.
Cyclin A2/E1 activation defines a hepatocellular carcinoma subclass with a rearrangement signature of replication stress
Authors: Bayard Quentin , Meunier Léa , Peneau Camille , Renault Victor , Shinde Jayendra , Nault Jean-Charles , Mami Iadh , Couchy Gabrielle , Amaddeo Giuliana , Tubacher Emmanuel , Bacq Delphine , Meyer Vincent , La Bella Tiziana , Debaillon-Vesque Audrey , Bioulac-Sage Paulette , Seror Olivier , Blanc Jean-Frédéric , Calderaro Julien , Deleuze Jean-François , Imbeaud Sandrine , Zucman-Rossi Jessica , Letouzé Eric
Published: December 2018

Cyclins A2 and E1 regulate the cell cycle by promoting S phase entry and progression. Here, we identify a hepatocellular carcinoma (HCC) subgroup exhibiting cyclin activation through various mechanisms including hepatitis B virus (HBV) and adeno-associated virus type 2 (AAV2) insertions, enhancer hijacking and recurrent CCNA2 fusions. Cyclin A2 or E1 alterations define a homogenous entity of aggressive HCC, mostly developed in non-cirrhotic patients, characterized by a transcriptional activation of E2F and ATR pathways and a high frequency of RB1 and PTEN inactivation. Cyclin-driven HCC display a unique signature of structural rearrangements with hundreds of tandem duplications and templated insertions frequently activating TERT promoter. These rearrangements, strongly enriched in early-replicated active chromatin regions, are consistent with a break-induced replication mechanism. Pan-cancer analysis reveals a similar signature in BRCA1-mutated breast and ovarian cancers. Together, this analysis reveals a new poor prognosis HCC entity and a rearrangement signature related to replication stress.
Neural representation of visual concepts in people born blind
Authors: Striem-Amit Ella , Wang Xiaoying , Bi Yanchao , Caramazza Alfonso
Published: December 2018

How do we represent information without sensory features? How are abstract concepts like “freedom”, devoid of external perceptible referents, represented in the brain? Here, to address the role of sensory information in the neural representation of concepts, we used fMRI to investigate how people born blind process concepts whose referents are imperceptible to them because of their visual nature (“rainbow”, “red”). Activity for these concepts was compared to that of sensorially-perceptible referents (“rain”), classical abstract concepts (“justice”) and concrete concepts (“cup”), providing a gradient between fully concrete and fully abstract concepts in the blind. We find that anterior temporal lobe (ATL) responses track concept perceptibility and objecthood: preference for imperceptible object concepts was found in dorsal ATL, for abstract (non-object, non-referential) concepts in lateral ATL, and for perceptible concepts in medial ATL. These findings point to a new division-of-labor among aspects of ATL in representing conceptual properties that are abstract in different ways.
Frequency-tunable toughening in a polymer-metal-ceramic stack using an interfacial molecular nanolayer
Authors: Kwan Matthew , Braccini Muriel , Lane Michael W. , Ramanath Ganpati
Published: December 2018

Interfacial toughening in composite materials is reasonably well understood for static loading, but little is known for cyclic loading. Here, we demonstrate that introducing an interfacial molecular nanolayer at the metal-ceramic interface of a layered polymer-metal-ceramic stack triples the fracture energy for ~75–300 Hz loading, yielding 40% higher values than the static-loading fracture energy. We show that this unexpected frequency-dependent toughening is underpinned by nanolayer-induced interface strengthening, which facilitates load transfer to, and plasticity in, the polymer layer. Above a threshold interfacial bond strength, the toughening magnitude and frequency range are primarily controlled by the frequency- and temperature-dependent rheological properties of the polymer. These results indicate the tunability of the toughening behavior through suitable choice of interfacial molecular layers and polymers. Our findings open up possibilities for realizing novel composites with inorganic-organic interfaces, e.g., arresting crack growth or stimulating controlled fracture triggered by loads with specific frequency characteristics.
Decoding arm speed during reaching
Authors: Inoue Yoh , Mao Hongwei , Suway Steven B. , Orellana Josue , Schwartz Andrew B.
Published: December 2018

Neural prostheses decode intention from cortical activity to restore upper extremity movement. Typical decoding algorithms extract velocity—a vector quantity with direction and magnitude (speed) —from neuronal firing rates. Standard decoding algorithms accurately recover arm direction, but the extraction of speed has proven more difficult. We show that this difficulty is due to the way speed is encoded by individual neurons and demonstrate how standard encoding-decoding procedures produce characteristic errors. These problems are addressed using alternative brain–computer interface (BCI) algorithms that accommodate nonlinear encoding of speed and direction. Our BCI approach leads to skillful control of both direction and speed as demonstrated by stereotypic bell-shaped speed profiles, straight trajectories, and steady cursor positions before and after the movement.
Pan-cancer characterisation of microRNA across cancer hallmarks reveals microRNA-mediated downregulation of tumour suppressors
Authors: Dhawan Andrew , Scott Jacob G. , Harris Adrian L. , Buffa Francesca M.
Published: December 2018

microRNAs are key regulators of the human transcriptome across a number of diverse biological processes, such as development, aging and cancer, where particular miRNAs have been identified as tumour suppressive and oncogenic. In this work, we elucidate, in a comprehensive manner, across 15 epithelial cancer types comprising 7316 clinical samples from the Cancer Genome Atlas, the association of miRNA expression and target regulation with the phenotypic hallmarks of cancer. Utilising penalised regression techniques to integrate transcriptomic, methylation and mutation data, we find evidence for a complex map of interactions underlying the relationship of miRNA regulation and the hallmarks of cancer. This highlighted high redundancy for the oncomiR-1 cluster of oncogenic miRNAs, in particular hsa-miR-17-5p. In addition, we reveal extensive miRNA regulation of tumour suppressor genes such as PTEN, FAT4 and CDK12, uncovering an alternative mechanism of repression in the absence of mutation, methylation or copy number changes.
Role of NS1 antibodies in the pathogenesis of acute secondary dengue infection
Authors: Jayathilaka Deshni , Gomes Laksiri , Jeewandara Chandima , Jayarathna Geethal. S. Bandara , Herath Dhanushka , Perera Pathum Asela , Fernando Samitha , Wijewickrama Ananda , Hardman Clare S. , Ogg Graham S. , Malavige Gathsaurie Neelika
Published: December 2018

The role of NS1-specific antibodies in the pathogenesis of dengue virus infection is poorly understood. Here we investigate the immunoglobulin responses of patients with dengue fever (DF) and dengue hemorrhagic fever (DHF) to NS1. Antibody responses to recombinant-NS1 are assessed in serum samples throughout illness of patients with acute secondary DENV1 and DENV2 infection by ELISA. NS1 antibody titres are significantly higher in patients with DHF compared to those with DF for both serotypes, during the critical phase of illness. Furthermore, during both acute secondary DENV1 and DENV2 infection, the antibody repertoire of DF and DHF patients is directed towards distinct regions of the NS1 protein. In addition, healthy individuals, with past non-severe dengue infection have a similar antibody repertoire as those with mild acute infection (DF). Therefore, antibodies that target specific NS1 epitopes could predict disease severity and be of potential benefit in aiding vaccine and treatment design.
A machine learning approach for online automated optimization of super-resolution optical microscopy
Authors: Durand Audrey , Wiesner Theresa , Gardner Marc-André , Robitaille Louis-Émile , Bilodeau Anthony , Gagné Christian , De Koninck Paul , Lavoie-Cardinal Flavie
Published: December 2018

Traditional approaches for finding well-performing parameterizations of complex imaging systems, such as super-resolution microscopes rely on an extensive exploration phase over the illumination and acquisition settings, prior to the imaging task. This strategy suffers from several issues: it requires a large amount of parameter configurations to be evaluated, it leads to discrepancies between well-performing parameters in the exploration phase and imaging task, and it results in a waste of time and resources given that optimization and final imaging tasks are conducted separately. Here we show that a fully automated, machine learning-based system can conduct imaging parameter optimization toward a trade-off between several objectives, simultaneously to the imaging task. Its potential is highlighted on various imaging tasks, such as live-cell and multicolor imaging and multimodal optimization. This online optimization routine can be integrated to various imaging systems to increase accessibility, optimize performance and improve overall imaging quality.
An AIEgen-based 3D covalent organic framework for white light-emitting diodes
Authors: Ding Huimin , Li Jian , Xie Guohua , Lin Guiqing , Chen Rufan , Peng Zhengkang , Yang Chuluo , Wang Baoshan , Sun Junliang , Wang Cheng
Published: December 2018

The design and synthesis of three-dimensional covalent organic frameworks (3D COFs) have still been considered as a big challenge. Here we report the design and synthesis of an AIEgen-based 3D COF (3D-TPE-COF), with a high surface area (1084 m2 g−1). According to powder X-ray diffraction and continuous rotation electron diffraction analyses, 3D-TPE-COF is identified to adopt a seven-fold interpenetrated pts topology. Interestingly, 3D-TPE-COF emits yellow fluorescence upon excitation, with a photoluminescence quantum yield of 20%. Moreover, by simply coating 3D-TPE-COF onto a commercial blue light-emitting diode (LED), a prototype white LED (WLED) under continuously driving without degradation for 1200 h was demonstrated. The present work suggests the possibility of using COF materials for stable WLEDs, which will greatly inspire us to design and synthesize fluorescent 3D COFs and facilitate the development of COF-based WLEDs in future.
Efficient oxygen evolution electrocatalysis in acid by a perovskite with face-sharing IrO6 octahedral dimers
Authors: Yang Lan , Yu Guangtao , Ai Xuan , Yan Wensheng , Duan Hengli , Chen Wei , Li Xiaotian , Wang Ting , Zhang Chenghui , Huang Xuri , Chen Jie-Sheng , Zou Xiaoxin
Published: December 2018

The widespread use of proton exchange membrane water electrolysis requires the development of more efficient electrocatalysts containing reduced amounts of expensive iridium for the oxygen evolution reaction (OER). Here we present the identification of 6H-phase SrIrO3 perovskite (6H-SrIrO3) as a highly active electrocatalyst with good structural and catalytic stability for OER in acid. 6H-SrIrO3 contains 27.1 wt% less iridium than IrO2, but its iridium mass activity is about 7 times higher than IrO2, a benchmark electrocatalyst for the acidic OER. 6H-SrIrO3 is the most active catalytic material for OER among the iridium-based oxides reported recently, based on its highest iridium mass activity. Theoretical calculations indicate that the existence of face-sharing octahedral dimers is mainly responsible for the superior activity of 6H-SrIrO3 thanks to the weakened surface Ir-O binding that facilitates the potential-determining step involved in the OER (i.e., O* + H2O → HOO* + H+ + e¯).
Inhibitor binding mode and allosteric regulation of Na+-glucose symporters
Authors: Bisignano Paola , Ghezzi Chiara , Jo Hyunil , Polizzi Nicholas F. , Althoff Thorsten , Kalyanaraman Chakrapani , Friemann Rosmarie , Jacobson Matthew P. , Wright Ernest M. , Grabe Michael
Published: December 2018

Sodium-dependent glucose transporters (SGLTs) exploit sodium gradients to transport sugars across the plasma membrane. Due to their role in renal sugar reabsorption, SGLTs are targets for the treatment of type 2 diabetes. Current therapeutics are phlorizin derivatives that contain a sugar moiety bound to an aromatic aglycon tail. Here, we develop structural models of human SGLT1/2 in complex with inhibitors by combining computational and functional studies. Inhibitors bind with the sugar moiety in the sugar pocket and the aglycon tail in the extracellular vestibule. The binding poses corroborate mutagenesis studies and suggest a partial closure of the outer gate upon binding. The models also reveal a putative Na+ binding site in hSGLT1 whose disruption reduces the transport stoichiometry to the value observed in hSGLT2 and increases inhibition by aglycon tails. Our work demonstrates that subtype selectivity arises from Na+-regulated outer gate closure and a variable region in extracellular loop EL5.
Host-targeted niclosamide inhibits C. difficile virulence and prevents disease in mice without disrupting the gut microbiota
Authors: Tam John , Hamza Therwa , Ma Bing , Chen Kevin , Beilhartz Greg L. , Ravel Jacques , Feng Hanping , Melnyk Roman A.
Published: December 2018

Clostridium difficile is the leading cause of nosocomial diarrhea and colitis in the industrialized world. Disruption of the protective gut microbiota by antibiotics enables colonization by multidrug-resistant C. difficile, which secrete up to three different protein toxins that are responsible for the gastrointestinal sequelae. Oral agents that inhibit the damage induced by toxins, without altering the gut microbiota, are urgently needed to prevent primary disease and break the cycle of antibiotic-induced disease recurrence. Here, we show that the anthelmintic drug, niclosamide, inhibits the pathogenesis of all three toxins by targeting a host process required for entry into colonocytes by each toxin. In mice infected with an epidemic strain of C. difficile, expressing all three toxins, niclosamide reduced both primary disease and recurrence, without disrupting the diversity or composition of the gut microbiota. Given its excellent safety profile, niclosamide may address an important unmet need in preventing C. difficile primary and recurrent diseases.
Anomalous diffusion along metal/ceramic interfaces
Authors: Kumar Aakash , Barda Hagit , Klinger Leonid , Finnis Michael W. , Lordi Vincenzo , Rabkin Eugen , Srolovitz David J.
Published: December 2018

Interface diffusion along a metal/ceramic interface present in numerous energy and electronic devices can critically affect their performance and stability. Hole formation in a polycrystalline Ni film on an α-Al2O3 substrate coupled with a continuum diffusion analysis demonstrates that Ni diffusion along the Ni/α-Al2O3 interface is surprisingly fast. Ab initio calculations demonstrate that both Ni vacancy formation and migration energies at the coherent Ni/α-Al2O3 interface are much smaller than in bulk Ni, suggesting that the activation energy for diffusion along coherent Ni/α-Al2O3 interfaces is comparable to that along (incoherent/high angle) grain boundaries. Based on these results, we develop a simple model for diffusion along metal/ceramic interfaces, apply it to a wide range of metal/ceramic systems and validate it with several ab initio calculations. These results suggest that fast metal diffusion along metal/ceramic interfaces should be common, but is not universal.
Author Correction: Identifying long-term stable refugia for relict plant species in East Asia
Authors: Tang Cindy Q. , Matsui Tetsuya , Ohashi Haruka , Dong Yi-Fei , Momohara Arata , Herrando-Moraira Sonia , Qian Shenhua , Yang Yongchuan , Ohsawa Masahiko , Luu Hong Truong , Grote Paul J. , Krestov Pavel V. , LePage Ben , Werger Marinus , Robertson Kevin , Hobohm Carsten , Wang Chong-Yun , Peng Ming-Chun , Chen Xi , Wang Huan-Chong , Su Wen-Hua , Zhou Rui , Li Shuaifeng , He Long-Yuan , Yan Kai , Zhu Ming-Yuan , Hu Jun , Yang Ruo-Han , Li Wang-Jun , Tomita Mizuki , Wu Zhao-Lu , Yan Hai-Zhong , Zhang Guang-Fei , He Hai , Yi Si-Rong , Gong Hede , Song Kun , Song Ding , Li Xiao-Shuang , Zhang Zhi-Ying , Han Peng-Bin , Shen Li-Qin , Huang Diao-Shun , Luo Kang , López-Pujol Jordi
Published: December 2018

In the original version of this Article, an incorrect sample size was provided for the number of relict species (443 instead of 442) and the number of relict forests (423 instead of 422). These errors have been corrected in both the PDF and HTML versions of the Article.
Kinetics of pipeline steel corrosion studied by Raman spectroscopy-coupled vertical scanning interferometry
Authors: Heuer Janis , Luttge Andreas
Published: December 2018

The corrosion and degradation of materials, such as pipeline steel, have a strong effect on both the environment and the economy. The quantification of these processes can therefore provide important information needed to manage their impact. In this study, a concept for the characterization and quantification of corrosion is demonstrated on API X70 steel immersed in 3.5 wt.% NaCl solution. Due to the difficulty of quantifying corrosion rates, e.g., through single mean values, a unique system is applied that directly couples Raman spectroscopy with vertical scanning interferometry to assess the physical and chemical aspects of steel corrosion kinetics. Vertical scanning interferometry allows the quantification of the topographical evolution of corrosion product formation and material dissolution in combination with the direct measurements of the respective rates. The Raman spectroscopy provides additional information about the (mineral) phases. Rate variations ranging from uniform corrosion to areas of high pit densities are quantified and analyzed in rate maps and subsequently visualized in rate spectra. The rate distribution is classified into different domains and pitting rates. Thus, a comprehensive quantitative assessment of the characteristic corrosion behavior is discussed.
The maturation of speech structure in psychosis is resistant to formal education
Authors: Mota Natália Bezerra , Sigman Mariano , Cecchi Guillermo , Copelli Mauro , Ribeiro Sidarta
Published: December 2018

Discourse varies widely with age, level of education, and psychiatric state. Word graphs have been recently shown to provide behavioral markers of formal thought disorders in psychosis (e.g., disorganized flow of ideas) and to track literacy acquisition in children with typical development. Here we report that a graph-theoretical computational analysis of verbal reports from subjects spanning 6 decades of age and 2 decades of education reveals asymptotic changes over time that depend more on education than age. In typical subjects, short-range recurrence and lexical diversity stabilize after elementary school, whereas graph size and long-range recurrence only steady after high school. Short-range recurrence decreases towards random levels, while lexical diversity, long-range recurrence, and graph size increase away from near-randomness towards a plateau in educated adults. Subjects with psychosis do not show similar dynamics, presenting at adulthood a children-like discourse structure. Typical subjects increase the range of word recurrence over school years, but the same feature in subjects with psychosis resists education.
Ultrasonography for lymph nodes metastasis identification in bitches with mammary neoplasms
Authors: Silva Priscila , Uscategui Ricardo Andres Ramirez , Maronezi Marjury Cristina , Gasser Beatriz , Pavan Letícia , Gatto Igor Renan Honorato , de Almeida Vivian Tavares , Vicente Wilter Ricardo Russiano , Feliciano Marcus Antônio Rossi
Published: December 2018

The aim of this study was to evaluate and compare the diagnostic accuracy of B-mode, Doppler ultrasonography and Acoustic Radiation Force Impulse (ARFI) elastography in the identification of axillary and inguinal lymph nodes metastasis in bitches with mammary neoplasms. The axillary (n = 96) and inguinal (n = 100) lymph nodes of 100 bitches were evaluated using B-Mode, Colour Doppler and ARFI-elastography. After this evaluation, mastectomy and lymph nodes excision were performed and these structures were histologically classified as free, reactive or metastatic. Ultrasonographic parameters were compared by Chi-Square or ANOVA tests and if they are significant, discriminative power analysis according to histopathological classification was performed (ROC analysis). The ARFI-elastography shear wave velocity (SWV) enabled metastasis identification in inguinal (sensitivity 95% specificity 87%) and axillary lymph nodes (sensitivity 100% specificity 94%). While B-Mode ultrasound Short/Long axis ratio evaluation of inguinal and axillary lymph nodes only resulted in a sensitivity around of 71% and specificity of 55%. In conclusion, B-Mode ultrasonography may contribute to diagnosis of metastasis in axillary and inguinal lymph nodes of bitches affected by mammary neoplasm with limited accuracy, while SWV evaluation proved to be an excellent diagnosis tool, which allows differentiation between free, reactive and tumour metastatic lymph nodes.
The autosomal Gsdf gene plays a role in male gonad development in Chinese tongue sole (Cynoglossus semilaevis)
Authors: Zhu Ying , Meng Liang , Xu Wenteng , Cui Zhongkai , Zhang Nianwei , Guo Hua , Wang Na , Shao Changwei , Chen Songlin
Published: December 2018

Gsdf is a key gene for testicular differentiation in teleost. However, little is known about the function of Gsdf in Chinese tongue sole (Cynoglossus semilaevis). In this study, we obtained the full-length Gsdf gene (CS-Gsdf), and functional characterization revealed its potential participation during germ cell differentiation in testes. CS-Gsdf transcription was predominantly detected in gonads, while the levels in testes were significantly higher than those in ovaries. During the different developmental stages in male gonads, the mRNA level was significantly upregulated at 86 dph, and a peak appeared at 120 dph; then, the level decreased at 1 and 2 yph. In situ hybridization revealed that CS-Gsdf mRNA was mainly localized in the Sertoli cells, spermatogonia, and spermatids in mature testes. After CS-Gsdf knockdown in the male testes cell line by RNA interference, a series of sex-related genes was influenced, including several sex differentiation genes, CS-Wnt4a, CS-Cyp19a1a and CS-Star. Based on these data, we speculated that CS-Gsdf may play a positive role in germ differentiation and proliferation via influencing genes related to sex differentiation.
CASP4 gene silencing in epithelial cancer cells leads to impairment of cell migration, cell-matrix adhesion and tissue invasion
Authors: Papoff Giuliana , Presutti Dario , Lalli Cristiana , Bolasco Giulia , Santini Simonetta , Manelfi Candida , Fustaino Valentina , Alemà Stefano , Ruberti Giovina
Published: December 2018

Inflammatory caspases, including human caspase-4 (CASP4), play key roles in innate immune responses to promote fusion of phagosomes harboring pathogenic bacteria with lysosomes, halt intracellular replication of pathogens, maturation and secretion of pro-inflammatory cytokines. The role of inflammatory caspases in cancer cells remains poorly investigated. Here, we explored the consequences of modulating CASP4 expression levels on the migratory behavior of epithelial cancer cell lines. By a gene silencing approach and in vitro and in vivo studies we show that down-regulation of CASP4 leads to impaired cell migration and cell-matrix adhesion. This phenotype is accompanied by an increased actin cytoskeleton polymerization, changes in the overall organization of adherens junctions (AJs) and number and size of focal adhesions. Interestingly, the cell migration deficit could be reversed by epithelial growth factor treatment, and depletion of calcium ions unveiled a role of CASP4 in the novo assembly of AJs, suggesting that the role of CASP4 is not cell-autonomous. Finally, CASP4-silenced A431 cells exhibited a severe reduction in their ability to invade lung tissue, when injected into nude mice. Overall, our data support the emerging evidence that inflammatory caspases can regulate cell migration through actin remodeling and uncover a novel role of CASP4 in cancer cell behavior.
In Vivo Evaluation of PAX6 Overexpression and NMDA Cytotoxicity to Stimulate Proliferation in the Mouse Retina
Authors: Ranaei Pirmardan Ehsan , Soheili Zahra-Soheila , Samiei Shahram , Ahmadieh Hamid , Mowla Seyed Javad , Naseri Marzieh , Daftarian Narsis
Published: December 2018

Retinal degenerative diseases, due to the lack of regeneration systems and self-renewable cells, often lead to visual impairment. Pax6 is a pleiotropic transcription factor and its expression level determines self-renewal status or differentiation of retinal cells. Here, we investigated the fate of simultaneous induction of retinal ganglion cell death and Pax6 overexpression in retro-differentiation of retinal cells and their commitment to re-enter into the cell cycle. Induction of acute retinal ganglion cell death and generation of mouse experimental model was performed by N-methyl D-aspartic acid (NMDA) injection. Recombinant AAV2 virus harboring PAX6 cDNA and reporter gene was injected into untreated and model mouse eyes. Histological analyses, including IHC and retinal flatmounts immunostaining were performed. The number of Ki67+ cells was clearly increased in model mice, presumably due to NMDA treatment and regardless of Pax6 over-expression. Unlike previous studies, Ki67+ cells were found in GCL layer and interestingly ONL cells expressed Sox2 stemness marker after NMDA cytotoxicity. The potential of retinal cells for robust Ki67 expression, after injury, and expression of Sox2, confirmed their intrinsic plasticity and made a vivid prospect for retinal regenerative medicine.
T cell-derived lymphotoxin limits Th1 response during HSV-1 infection
Authors: Yang Kaiting , Liang Yong , Sun Zhichen , Liu Longchao , Liao Jing , Xu Hairong , Zhu Mingzhao , Fu Yang-Xin , Peng Hua
Published: December 2018

Though lymphotoxin (LT) is highly expressed by type I helper T (Th1) cells, its contribution to CD4+T cell differentiation during infections and diseases remains a mystery. In HSV-1 infection, we observed that LTβR signaling is required to limit the Th1 response. Using bone marrow chimeric mice, mixed-T-cell chimeric mice, and LTβRin vivoblockades, we unexpectedly observed that LT, especially T cell-derived LT, played an indispensable role in limiting the Th1 response. The LTβR-Ig blockade promoted the Th1 response by increasing infiltration of monocytes and monocyte-derived DCs and up-regulating IL-12 secretion in the lymphoid environment. Our findings identified a novel role for T cell-derived LT in manipulating Th1 differentiation.
Elucidating the contribution of ETC complexes I and II to the respirasome formation in cardiac mitochondria
Authors: Jang Sehwan , Javadov Sabzali
Published: December 2018

Mitochondrial electron transport chain (ETC) plays a central role in ATP synthesis, and its dysfunction is associated with human diseases. Recent studies revealed that individual ETC complexes are assembled into supercomplexes. The main supercomplex, respirasome composed of complexes I, III, and IV has been suggested to improve electron channeling and control ROS production, maintain the structural integrity of ETC complexes and prevent protein aggregation in the inner mitochondrial membrane. However, many questions related to the structural organization of the respirasome, particularly, a possible role of complexes I and II in respirasome formation remain unclear. Here, we investigated whether genetic and pharmacological inhibition of complexes I and II affect respirasome assembly in cardioblast cells and isolated cardiac mitochondria. Pharmacological inhibition of the enzymatic activity of complexes I and II stimulated disruption of the respirasome. Likewise, knockdown of the complex I subunit NDUFA11 stimulated dissociation of respirasome and reduced the activity of complexes I, III, and IV. However, silencing of the membrane-anchored SDHC subunit of complex II had no effect on the respirasome assembly but reduced the activity of complexes II and IV. Downregulation of NDUFA11 or SDHC reduced ATP production and increased mitochondrial ROS production. Overall, these studies, for the first time, provide biochemical evidence that the complex I activity, and the NDUFA11 subunit are important for assembly and stability of the respirasome. The SDHC subunit of complex II is not involved in the respirasome however the complex may play a regulatory role in respirasome formation.