bluuebunny/crossref_metadata_2025 huggingface dataset:
SCFβ-TrCP-mediated degradation of TOP2β promotes cancer cell survival in response to chemotherapeutic drugs targeting topoisomerase II
Authors: Shu Jianfeng , Cui Danrui , Ma Ying , Xiong Xiufang , Sun Yi , Zhao Yongchao
Published: February 2020

Topoisomerase II (TOP2)-targeting anticancer chemotherapeutic drugs, termed TOP2 poisons, are widely used and effective in the clinic by stabilizing TOP2-DNA covalent complexes to induce DNA double-strand breaks (DSBs) and ultimately, cause cell death. The stabilized TOP2-DNA complex is known to be degraded by proteasome, whereas the underlying mechanism for instant TOP2β degradation in response to TOP2 poisons and the subsequent biological consequence remain elusive. Here, we reported that TOP2 poison-induced TOP2β degradation is mediated by SCFβ-TrCP ubiquitin ligase. Specifically, DNA damage signal, triggered by teniposide (VM-26) treatment, activates ATM, cooperating with CK1 to phosphorylate TOP2β on Ser1134 and Ser1130, respectively, in a canonical degron motif to facilitate β-TrCP binding and subsequent degradation. Inactivation of ATM, CK1 or SCFβ-TrCP by small molecular inhibitors or genetic knockdown/knockout abrogates TOP2β degradation. Biologically, blockage of TOP2β degradation in combination with VM-26 treatment impairs DNA damage response and repair, leading to an accelerated cell death via apoptosis. Thus, it appears that TOP2β degradation is a cellular defensive mechanism to facilitate the exposure of DSBs to trigger DNA damage response and repair. Collectively, our findings reveal a new strategy to improve the efficacy of TOP2 poisons in combination with small-molecule inhibitors against TOP2β degradation.
Ice Ic without stacking disorder by evacuating hydrogen from hydrogen hydrate
Authors: Komatsu Kazuki , Machida Shinichi , Noritake Fumiya , Hattori Takanori , Sano-Furukawa Asami , Yamane Ryo , Yamashita Keishiro , Kagi Hiroyuki
Published: February 2020

Water freezes below 0 °C at ambient pressure ordinarily to ice Ih, with hexagonal stacking sequence. Under certain conditions, ice with a cubic stacking sequence can also be formed, but ideal ice Ic without stacking-disorder has never been formed until recently. Here we demonstrate a route to obtain ice Ic without stacking-disorder by degassing hydrogen from the high-pressure form of hydrogen hydrate, C2, which has a host framework isostructural with ice Ic. The stacking-disorder free ice Ic is formed from C2 via an intermediate amorphous or nano-crystalline form under decompression, unlike the direct transformations occurring in ice XVI from neon hydrate, or ice XVII from hydrogen hydrate. The obtained ice Ic shows remarkable thermal stability, until the phase transition to ice Ih at 250 K, originating from the lack of dislocations. This discovery of ideal ice Ic will promote understanding of the role of stacking-disorder on the physical properties of ice as a counter end-member of ice Ih.
A phosphorylation-based switch controls TAA1-mediated auxin biosynthesis in plants
Authors: Wang Qian , Qin Guochen , Cao Min , Chen Rong , He Yuming , Yang Liyuan , Zeng Zhejun , Yu Yongqiang , Gu Yangtao , Xing Weiman , Tao W. Andy , Xu Tongda
Published: February 2020

Auxin determines the developmental fate of plant tissues, and local auxin concentration is precisely controlled. The role of auxin transport in modulating local auxin concentration has been widely studied but the regulation of local auxin biosynthesis is less well understood. Here, we show that TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA1), a key enzyme in the auxin biosynthesis pathway in Arabidopsis thaliana is phosphorylated at Threonine 101 (T101). T101 phosphorylation status can act as an on/off switch to control TAA1-dependent auxin biosynthesis and is required for proper regulation of root meristem size and root hair development. This phosphosite is evolutionarily conserved suggesting post-translational regulation of auxin biosynthesis may be a general phenomenon. In addition, we show that auxin itself, in part via TRANS-MEMBRANE KINASE 4 (TMK4), can induce T101 phosphorylation of TAA1 suggesting a self-regulatory loop whereby local auxin signalling can suppress biosynthesis. We conclude that phosphorylation-dependent control of TAA1 enzymatic activity may contribute to regulation of auxin concentration in response to endogenous and/or external cues.
Two-stage electro–mechanical coupling of a KV channel in voltage-dependent activation
Authors: Hou Panpan , Kang Po Wei , Kongmeneck Audrey Deyawe , Yang Nien-Du , Liu Yongfeng , Shi Jingyi , Xu Xianjin , White Kelli McFarland , Zaydman Mark A. , Kasimova Marina A. , Seebohm Guiscard , Zhong Ling , Zou Xiaoqin , Tarek Mounir , Cui Jianmin
Published: February 2020

In voltage-gated potassium (KV) channels, the voltage-sensing domain (VSD) undergoes sequential activation from the resting state to the intermediate state and activated state to trigger pore opening via electro–mechanical (E–M) coupling. However, the spatial and temporal details underlying E–M coupling remain elusive. Here, utilizing KV7.1’s unique two open states, we report a two-stage E–M coupling mechanism in voltage-dependent gating of KV7.1 as triggered by VSD activations to the intermediate and then activated state. When the S4 segment transitions to the intermediate state, the hand-like C-terminus of the VSD-pore linker (S4-S5L) interacts with the pore in the same subunit. When S4 then proceeds to the fully-activated state, the elbow-like hinge between S4 and S4-S5L engages with the pore of the neighboring subunit to activate conductance. This two-stage hand-and-elbow gating mechanism elucidates distinct tissue-specific modulations, pharmacology, and disease pathogenesis of KV7.1, and likely applies to numerous domain-swapped KVchannels.
Tropical cyclone rainbands can trigger meteotsunamis
Authors: Shi Luming , Olabarrieta Maitane , Nolan David S. , Warner John C.
Published: February 2020

Tropical cyclones are one of the most destructive natural hazards and much of the damage and casualties they cause are flood-related. Accurate characterization and prediction of total water levels during extreme storms is necessary to minimize coastal impacts. While meteotsunamis are known to influence water levels and to produce severe consequences, their impacts during tropical cyclones are underappreciated. This study demonstrates that meteotsunami waves commonly occur during tropical cyclones, and that they can contribute significantly to total water levels. We use an idealized coupled ocean–atmosphere–wave numerical model to analyze tropical cyclone-induced meteotsunami generation and propagation mechanisms. We show that the most extreme meteotsunami events are triggered by inherent features of the structure of tropical cyclones: inner and outer spiral rainbands. While outer distant spiral rainbands produce single-peak meteotsunami waves, inner spiral rainbands trigger longer lasting wave trains on the front side of the tropical cyclones.
Deep Analysis of Residue Constraints (DARC): identifying determinants of protein functional specificity
Authors: Tondnevis Farzaneh , Dudenhausen Elizabeth E. , Miller Andrew M. , McKenna Robert , Altschul Stephen F. , Bloom Linda B. , Neuwald Andrew F.
Published: February 2020

Protein functional constraints are manifest as superfamily and functional-subgroup conserved residues, and as pairwise correlations. Deep Analysis of Residue Constraints (DARC) aids the visualization of these constraints, characterizes how they correlate with each other and with structure, and estimates statistical significance. This can identify determinants of protein functional specificity, as we illustrate for bacterial DNA clamp loader ATPases. These load ring-shaped sliding clamps onto DNA to keep polymerase attached during replication and contain one δ, three γ, and one δ’ AAA+ subunits semi-circularly arranged in the order δ-γ1-γ2-γ3-δ’. Only γ is active, though both γ and δ’ functionally influence an adjacent γ subunit. DARC identifies, as functionally-congruent features linking allosterically the ATP, DNA, and clamp binding sites: residues distinctive of γ and of γ/δ’ that mutually interact in trans, centered on the catalytic base; several γ/δ’-residues and six γ/δ’-covariant residue pairs within the DNA binding N-termini of helices α2 and α3; and γ/δ’-residues associated with the α2 C-terminus and the clamp-binding loop. Most notable is a trans-acting γ/δ’ hydroxyl group that 99% of other AAA+ proteins lack. Mutation of this hydroxyl to a methyl group impedes clamp binding and opening, DNA binding, and ATP hydrolysis—implying a remarkably clamp-loader-specific function.
Boundary and vulnerability estimation of the internal borderzone using ischemic stroke lesion mapping
Authors: Grange Sylvain , Grange Rémi , Garnier Pierre , Varvat Jérôme , Marinescu Doina , Barral Fabrice-Guy , Boutet Claire , Schneider Fabien C.
Published: February 2020

Distinction between deep and superficial middle cerebral artery (MCA) territories and their junctional vascular area (the internal borderzone or IBZ) constitutes a predictor of stroke patient outcome. However, the IBZ boundaries are not well-defined because of substantial anatomical variance. Here, we built a statistical estimate of the IBZ and tested its vulnerability to ischemia using an independent sample. First, we used delineated lesions of 122 patients suffering of chronic ischemic stroke grouped in deep, superficial and territorial topographies and statistical comparisons to generate a probabilistic estimate of the IBZ. The IBZ extended from the insular cortex to the internal capsule and the anterior part of the caudate nucleus head. The IBZ showed the highest lesion frequencies (~30% on average across IBZ voxels) in our chronic stroke patients but also in an independent sample of 87 acute patients. Additionally, the most important apparent diffusion coefficient reductions (−6%), which reflect stroke severity, were situated within our IBZ estimate. The IBZ was most severely injured in case of a territorial infarction. Then, our results are in favour of an increased IBZ vulnerability to ischemia. Moreover, our probabilistic estimates of deep, superficial and IBZ regions can help the everyday spatial classification of lesions.
Three members of the yeast N-BAR proteins family form heterogeneous lattices in vivo and interact differentially with two RabGAP proteins
Authors: Prigent Magali , Chaillot Julien , Tisserand Hélène , Boy-Marcotte Emmanuelle , Cuif Marie-Hélène
Published: February 2020

The yeast N-BAR (Bin/Amphiphysin/Rvs167) protein Rvs167 is recruited by the Rab GTPase Activating Proteins (RabGAP) Gyp5 and Gyl1 to the tip of small buds to act in exocytosis. Investigating other N-BAR proteins involved in Gyp5/Gyl1/Rvs167 complexes, we found that Rvs161, an Rvs167 paralog, is absent from the complexes formed at the tip of small buds. Immunoprecipitation and Bimolecular Fluorescence Complementation (BiFC) analysis show that both Rvs167 and Rvs161 interact in vivo with Gvp36, an N-BAR protein. Rvs167 molecules also interact independently of Rvs161 and Gvp36. Rvs167/Rvs167 and Rvs167/Gyp5 interactions predominate over other combinations at the tip of small buds, suggesting that N-BAR lattices enriched in Rvs167 molecules form at these sites. By combining BiFC with markers specific to each organelle, we analyzed systematically in living cells the locations of the BiFC signals generated by combinations of the three N-BAR proteins. We show that the BiFC signals differ according to organelle and cell site, strongly suggesting heterogeneity in the composition of N-BAR protein lattices in vivo. Our results reveal that the organization of N-BAR protein lattices in vivo is complex and are consistent with N-BAR proteins forming various types of dimers and lattices of variable composition.
Identification of Quantitative Trait Loci Controlling Ethylene Production in Germinating Seeds in Maize (Zea mays L.)
Authors: Kong Dongdong , Fu Xiuyi , Jia Xiaohui , Wang Wenhui , Li Yi , Li Jiansheng , Yang Xiaohong , Ju Chuanli
Published: February 2020

Plant seed germination is a crucial developmental event that has significant effects on seedling establishment and yield production. This process is controlled by multiple intrinsic signals, particularly phytohormones. The gaseous hormone ethylene stimulates seed germination; however, the genetic basis of ethylene production in maize during seed germination remains poorly understood. In this study, we quantified the diversity of germination among 14 inbred lines representing the parental materials corresponding to multiple recombinant inbred line (RIL) mapping populations. Quantitative trait loci (QTLs) controlling ethylene production were then identified in germinating seeds from an RIL population constructed from two parental lines showing differences in both germination speed and ethylene production during germination. To explore the possible genetic correlations of ethylene production with other traits, seed germination and seed weight were evaluated using the same batch of samples. On the basis of high-density single nucleotide polymorphism-based genetic linkage maps, we detected three QTLs for ethylene production in germinating seeds, three QTLs for seed germination, and four QTLs for seed weight, with each QTL explaining 5.8%–13.2% of the phenotypic variation of the trait. No QTLs were observed to be co-localized, suggesting that the genetic bases underlying the three traits are largely different. Our findings reveal three chromosomal regions responsible for ethylene production during seed germination, and provide a valuable reference for the future investigation of the genetic mechanism underlying the role of the stress hormone ethylene in maize germination control under unfavourable external conditions.
Effect of High Calorie Diet on Intestinal Flora in LPS-Induced Pneumonia Rats
Authors: Bai Chen , Liu Tiegang , Xu Jingnan , Ma Xueyan , Huang Ling , Liu Shaoyang , Yu He , Chen Jianxin , Gu Xiaohong
Published: February 2020

Intestinal flora plays an important role in inflammatory response to systemic or local organs of its host. High calorie diet has been shown to aggravate the condition of pneumonia and delay recovery, especially in children. However, the underlying mechanisms remain unclear. This study placed SPF rats in a conventional environment, high calorie diet or LPS atomization was performed respectively or combined. Analysis of high-throughput sequencing of intestinal content combined with animal weight, organ index, serum inflammatory factors indicators and bioinformatics found that after pulmonary infection combined with a high-calorie diet, rats showed significant changes such as weight loss and increased lung weight index, and their lung and intestinal tissues showed more obvious inflammatory changes. And its gut flora structure suggests, the abundance of Leuconostocaceae in significantly reduced; abundance of Staphylococcus, Planococcaceae, Staphylococcus, Staphylococcaceae, Bacillales, Gemellales and Aerococcus significant increased. The study showed that high calorie diet and LPS atomization synergistically promoted pneumonia process in rat pups, which is related to changes in structure of intestinal flora. It is worth noting that pneumonia rats fed by convention diet also causing intestinal flora imbalance.
The mirtron miR-1010 functions in concert with its host gene SKIP to balance elevation of nAcRβ2
Authors: Amourda Christopher , Saunders Timothy E.
Published: February 2020

Mirtrons are non-canonical miRNAs arising by splicing and debranching from short introns. A plethora of introns have been inferred by computational analyses as potential mirtrons. Yet, few have been experimentally validated and their functions, particularly in relation to their host genes, remain poorly understood. Here, we found that Drosophila larvae lacking either the mirtron miR-1010 or its binding site in the nicotinic acetylcholine receptor β2 (nAcRβ2) 3′UTR fail to grow properly and pupariate. Increase of cortical nAcRβ2 mediated by neural activity elevates the level of intracellular Ca2+, which in turn activates CaMKII and, further downstream, the transcription factor Adf-1. We show that miR-1010 downregulates nAcRβ2. We reveal that Adf-1 initiates the expression of SKIP, the host gene of miR-1010. Preventing synaptic potentials from overshooting their optimal range requires both SKIP to temper synaptic potentials (incoherent feedforward loop) and miR-1010 to reduce nAcRβ2 mRNA levels (negative feedback loop). Our results demonstrate how a mirtron, in coordination with its host gene, contributes to maintaining appropriate receptor levels, which in turn may play a role in maintaining homeostasis.
Solution-Based Synthesis of Few-Layer WS2 Large Area Continuous Films for Electronic Applications
Authors: Abbas Omar A. , Zeimpekis Ioannis , Wang He , Lewis Adam H. , Sessions Neil P. , Ebert Martin , Aspiotis Nikolaos , Huang Chung-Che , Hewak Daniel , Mailis Sakellaris , Sazio Pier
Published: February 2020

Unlike MoS2 ultra-thin films, where solution-based single source precursor synthesis for electronic applications has been widely studied, growing uniform and large area few-layer WS2 films using this approach has been more challenging. Here, we report a method for growth of few-layer WS2 that results in continuous and uniform films over centimetre scale. The method is based on the thermolysis of spin coated ammonium tetrathiotungstate ((NH4)2WS4) films by two-step high temperature annealing without additional sulphurization. This facile and scalable growth method solves previously encountered film uniformity issues. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to confirm the few-layer nature of WS2 films. Raman and X-Ray photoelectron spectroscopy (XPS) revealed that the synthesized few-layer WS2 films are highly crystalline and stoichiometric. Finally, WS2 films as-deposited on SiO2/Si substrates were used to fabricate a backgated Field Effect Transistor (FET) device for the first time using this precursor to demonstrate the electronic functionality of the material and further validate the method.
Optimisation of Storage and Transportation Conditions of Cultured Corneal Endothelial Cells for Cell Replacement Therapy
Authors: Wahlig Stephen , Peh Gary S. L. , Adnan Khadijah , Ang Heng-Pei , Lwin Chan N. , Morales-Wong F. , Ong Hon Shing , Lovatt Matthew , Mehta Jodhbir S.
Published: February 2020

As the cornea is one of the most transplanted tissues in the body it has placed a burden on the provision of corneas from cadaveric donors. Corneal endothelial dysfunction is the leading indication for cornea transplant. Therefore, tissue engineering is emerging as an alternative approach to overcome the global shortage of transplant-grade corneas. The propagation and expansion of corneal endothelial cells has been widely reported. However, one obstacle to overcome is the transport and storage of corneal endothelial cells. In this study we investigated whether tissue engineered corneal endothelial cells can be preserved in hypothermic conditions. Human corneal endothelial cells (HCEnCs) were exposed to various temperatures (4 °C, 23 °C, and 37 °C) in both adherent and suspension storage models. Optimal storage media and storage duration was tested along with post-storage viability. Following storage and subsequent recovery at 37 °C, cell phenotype was assessed by immunofluorescence, gene and protein expression, and proliferative capacity analysis. Functionality was also assessed within a rabbit model of bullous keratopathy. Our data support our hypothesis that functional HCEnCs can be preserved in hypothermic conditions.
Clinical blood sampling for oxylipin analysis – effect of storage and pneumatic tube transport of blood on free and total oxylipin profile in human plasma and serum
Authors: Rund Katharina M. , Nolte Fabian , Doricic Julian , Greite Robert , Schott Sebastian , Lichtinghagen Ralf , Gueler Faikah , Schebb Nils Helge
Published: February 2020

Choice of blood specimen and suitable pre-analytical sample handling is crucial for quantitative oxylipin analysis in clinical studies.
Substrate interaction inhibits γ-secretase production of amyloid-β peptides
Authors: Zhao Jing , Xiao Yuanyuan , Liu Xinyue , Kim Soohyun , Wu Xianzhong , Barros Marilia , Zhuang Ran , Hou Xuben , Zhang Yingkai , Robakis Nikolaos K. , Li Yue-Ming , Dordick Jonathan S. , Ubarretxena-Belandia Iban , Wang Chunyu
Published: February 2020

A novel compound C1 interacts with C-terminal juxtamembrane lysines of amyloid precursor proteins and inhibits γ-secretase production of Aβ.
Synthesis of a conductive polymer thin film having a choline phosphate side group and its bioadhesive properties
Authors: Mukai Masaru , Cheng Chao-Hung , Ma Wei , Chin Mi , Lin Chia-Hsin , Luo Shyh-Chyang , Takahara Atsushi
Published: February 2020

A conductive polymer thin film having choline phosphate as the side group was prepared. The polymer thin film can prevent bovine serum albumin binding while present nice fibroblast cell adhesion.
Diamine-mediated degradative dimerisation of Morita–Baylis–Hillman ketones
Authors: Jha Ajit Kumar , Kumari Anju , Easwar Srinivasan
Published: February 2020

A degradative dimerisation of Morita–Baylis–Hillman ketones was observed in the presence of a primary diamine, resulting in methylene-bridged bis-1,3-dicarbonyl compounds.
Assembly of four new cobalt coordination polymers modulated by N-coligands: sensitive and selective sensing of nitroaromatics, Fe3+and Cr2O72−in water
Authors: Tu Qian-Qian , Ren Ling-Ling , Cui Ying-Ying , Cheng Ai-Ling , Gao En-Qing
Published: February 2020

Four new Co-CPs (1to4) have been obtained with the modulation of N-coligands.2and3can serve as multi-responsive sensors for rapid and sensitive detection of nitroaromatics, Fe3+and Cr2O72−in water.
Injection time controls the final morphology of nanocrystals during in situ-seeding synthesis of silver nanodisks
Authors: Gestraud Cécilia , Roblin Pierre , Morris Jeffrey F. , Meireles Martine , Hallez Yannick
Published: February 2020

We investigate an in situ-seeding synthesis of silver nanodisks based on the sequential addition of weak and strong reducing agents, ascorbic acid and sodium borohydride respectively, to silver nitrate at room temperature and in the presence of PVP.
Graphite-like polyoxometalate-based metal–organic framework as an efficient anode for lithium ion batteries
Authors: Yang Xiya , Zhu Peipei , Ma Xiaoliang , Li Wenjing , Tan Zenglong , Sha Jingquan
Published: February 2020

A new porous POM supported graphite-like MOF (Cu-POM) as a LIB anode material was designed and synthesized, and its lithium storage mechanism was explored using impedance spectra.
Direct EPR detection of atomic nitrogen in an atmospheric nitrogen plasma jet
Authors: Rostas Arpad Mihai , Ledernez Loic , Dietel Lisa , Heidinger Lorenz , Bergmann Michael , Altenburger Markus , Bruch Richard , Urban Gerald , Schleicher Erik , Weber Stefan
Published: February 2020

A nitrogen plasma generated by a self-designed microplasma device was analyzed by cw and pulse EPR spectroscopy in real time. Nitrogen atoms were detected and characterized in terms of spectral widths, relaxation times and actual concentrations.
A theoretical study on the binding and electrolytic splitting of hydrogen fluoride on Ni(111) and Ni(211)
Authors: Mattsson Stefan , Paulus Beate
Published: February 2020

Anhydrous hydrogen fluoride (HF) is electrochemically activated on Ni electrodes in the Simons process. We study the electrode/electrolyte interface using DFT methods and find the splitting of HF to be exothermic even at low cell potentials.
Gas phase dynamics, conformational transitions and spectroscopy of charged saccharides: the oxocarbenium ion, protonated anhydrogalactose and protonated methyl galactopyranoside
Authors: Dvores M. P. , Çarçabal P. , Maître P. , Simons J. P. , Gerber R. B.
Published: February 2020

Anhydrogalactose and the oxocarbenium ion have identical structure and electron delocalization in the sub-picosecond regime.
Single crystal neutron and magnetic measurements of Rb2Mn3(VO4)2CO3 and K2Co3(VO4)2CO3 with mixed honeycomb and triangular magnetic lattices
Authors: Smith Pellizzeri Tiffany M. , Sanjeewa Liurukara D. , Pellizzeri Steven , McMillen Colin D. , Garlea V. Ovidiu , Ye Feng , Sefat Athena S. , Kolis Joseph W.
Published: February 2020

Two new alkali vanadate carbonates with divalent transition metals have been synthesized as large single crystals via a high-temperature (600 °C) hydrothermal technique.
Metal-substituted tungstosulfates with Keggin structure: synthesis and characterization
Authors: Azuma Shinya , Kadoguchi Taiga , Eguchi Yohei , Hirabaru Hikaru , Ota Hiromi , Sadakane Masahiro , Yanagisawa Kazumichi , Hasegawa Takuya , Ueda Tadaharu
Published: February 2020

Simple synthetic procedures for accessing novel metal-substituted tungstosulfates [SMW11O39]4− (M = Mn2+, Co2+, Ni2+, and Cu2+) with Keggin-type structures were developed.
Determination of isotope fractionation of Cr(iii) during oxidation by LC/low-resolution MC-ICPMS
Authors: Karasiński Jakub , Nguyen-Marcińczyk Cuc Thi , Wojciechowski Marcin , Bulska Ewa , Halicz Ludwik
Published: February 2020

A robust and sensitive method for the precise isotopic analysis of 53Cr/50Cr during Cr(iii) oxidation by coupling ion pair reversed-phase chromatography and Multicollector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) is presented.
Integrating microfluidics and biosensing on a single flexible acoustic device using hybrid modes
Authors: Tao Ran , Reboud Julien , Torun Hamdi , McHale Glen , Dodd Linzi E. , Wu Qiang , Tao Kai , Yang Xin , Luo Jing Ting , Todryk Stephen , Fu Yongqing
Published: February 2020

A flexible thin film acoustofluidic device generates hybrid wave modes for microfluidic actuation (Lamb waves) and biosensing (thickness shear waves).
π-Extended push–pull azo-pyrrole photoswitches: synthesis, solvatochromism and optical band gaps
Authors: Balam-Villarreal J. A. , López-Mayorga B. J. , Gallardo-Rosas D. , Toscano R. A. , Carreón-Castro M. P. , Basiuk V. A. , Cortés-Guzmán F. , López-Cortés J. G. , Ortega-Alfaro M. C.
Published: February 2020

New push–pull biphenyl-azopyrrole photoswitches are efficiently obtainedviaa Suzuki cross-coupling reaction, give rise to J-type aggregates in binary MeOH : H2O solvents and undergo a water-assistedcis-to-transisomerization at room temperature.
6-Deoxy-6-fluoro galactofuranosides: regioselective glycosylation, unexpected reactivity, and anti-leishmanial activity
Authors: Vaugenot Jeane , El Harras Abderrafek , Tasseau Olivier , Marchal Rémi , Legentil Laurent , Le Guennic Boris , Benvegnu Thierry , Ferrières Vincent
Published: February 2020

Standard glycosylation of unprotected 6-fluorogalactofuranoside turned to three competitive reactions and afforded difuranosides able to impact growth of Leishmania tarentolae.
A simple and efficient approach toward deep-red to near-infrared-emitting iridium(iii) complexes for organic light-emitting diodes with external quantum efficiencies of over 10%
Authors: Chen Zhao , Zhang Hongyang , Wen Dawei , Wu Wenhai , Zeng Qingguang , Chen Shuming , Wong Wai-Yeung
Published: February 2020

The simplest and the most efficient deep-red to near-infrared-emitting emitters afford a new record external quantum efficiency for iridium(iii) complex based deep-red to near-infrared organic light-emitting diodes.
Size and charge dual-transformable mesoporous nanoassemblies for enhanced drug delivery and tumor penetration
Authors: Chen Liang , Zhao Tiancong , Zhao Mengyao , Wang Wenxing , Sun Caixia , Liu Lu , Li Qin , Zhang Fan , Zhao Dongyuan , Li Xiaomin
Published: February 2020

Size and charge dual-transformable core@satellite structured nanoassemblies are developed to overcome multiple biological barriers in a drug delivery system.
Design principles for metamorphic block copolymer assemblies
Authors: Ianiro Alessandro , Armes Steven P. , Tuinier Remco
Published: February 2020

Certain block copolymer assemblies in selective solvents undergo dynamic morphology transitions (metamorphism) on varying the solution temperature. We provide theoretical guidelines for an efficient design of these systems.
Tin negative electrodes using an FSA-based ionic liquid electrolyte: improved performance of potassium secondary batteries
Authors: Yamamoto Takayuki , Nohira Toshiyuki
Published: February 2020

Tin negative electrodes exhibited improved performance in an FSA-based ionic liquid electrolyte for potassium secondary batteries.
Bismuthanylstibanes
Authors: Marczenko Katherine M. , Chitnis Saurabh S.
Published: February 2020

The first examples of neutral Bi–Sb σ-bonds are reported and their reactivity is debuted.
A resorcinarene-based tetrabenzoimidazolylidene complex of rhodium
Authors: Ruiz-Botella Sheila , Vidossich Pietro , Ujaque Gregori , Peris Eduardo
Published: February 2020

A resorcinarene-based macromolecule bearing four rhodium benzoimidazolylidenes was obtained, and its fluxional behaviour was rationalized by means of DFT calculations.
Full-length NF-κB repressing factor contains an XRN2 binding domain
Authors: Alexandrova Jana , Piñeiro David , Jukes-Jones Rebekah , Mordue Ryan , Stoneley Mark , Willis Anne E.
Published: February 2020

NF-κB repressing factor (NKRF) was recently identified as an RNA binding protein that together with its associated proteins, the 5′–3′ exonuclease XRN2 and the helicase DHX15, is required to process the precursor ribosomal RNA. XRN2 is a multi-functional ribonuclease that is also involved in processing mRNAs, tRNAs and lncRNAs. The activity and stability of XRN2 are controlled by its binding partners, PAXT-1, CDKN2AIP and CDKN2AIPNL. In each case, these proteins interact with XRN2 via an XRN2 binding domain (XTBD), the structure and mode of action of which is highly conserved. Rather surprisingly, although NKRF interacts directly with XRN2, it was not predicted to contain such a domain, and NKRF's interaction with XRN2 was therefore unexplained. We have identified an alternative upstream AUG start codon within the transcript that encodes NKRF and demonstrate that the full-length form of NKRF contains an XTBD that is conserved across species. Our data suggest that NKRF is tethered in the nucleolus by binding directly to rRNA and that the XTBD in the N-terminal extension of NKRF is essential for the retention of XRN2 in this sub-organelle. Thus, we propose NKRF regulates the early steps of pre-rRNA processing during ribosome biogenesis by controlling the spatial distribution of XRN2 and our data provide further support for the XTBD as an XRN2 interacting motif.
β-Elemene suppresses tumor growth of diffuse large B-cell lymphoma through regulating lncRNA HULC-mediated apoptotic pathway
Authors: Hu Tonglin , Gao Yu
Published: February 2020

Background: Diffuse large B-cell lymphoma (DLBCL) is considered the most common aggressive subtype of lymphoma. A number of DLBCL patients fail to achieve a response to currently available therapies or develop resistance. β-Elemene is derived from herb Curcuma wenyujin, and exhibits anti-tumor activity in both solid and non-solid tumors through modulating several molecular signaling pathways. We aimed to explore the role of β-elemene in DLBCL treatment and elucidate the involved mechanism.

Materials and methods: Cell viability, apoptosis and expressions of related proteins were assessed and in vivo study were performed to determine the tumor suppressive effect of β-elemene and explore the molecular mechanisms.

Results: β-Elemene significantly suppressed the viability of DLBCL cells, and β-elemene down-regulated the lncRNA HULC expression and regulated key pro-apoptotic and anti-apoptotic proteins to induce significant apoptosis of DLBCL cells. HULC overexpression could decrease the β-elemene induced apoptosis, while HULC knockdown increased the apoptosis in DLBCL cells. In vivo study further confirmed that β-elemene could suppress the growth of DLBCL xenograft and regulate the HULC expression and the critical proteins of the apoptotic pathway.

Conclusion: β-Elemene performs as a tumor suppressor and modulator of HULC-mediated apoptotic pathway in DLBCL and will be an alternative candidate for clinical application.
Clinical characteristics of congenital lamellar cataract and myopia in a Chinese family
Authors: Liu Qing , Zhu Siquan
Published: February 2020

To investigate the clinical characteristics and the genetic defect in a Chinese family with congenital lamellar cataract with myopia. Three generations of a single family were recruited in the present study. A detailed family history and clinical data were recorded. A total of 100 unrelated ethnically matched controls without family history of congenital cataracts and myopia were also recruited. Genomic DNA was extracted from peripheral blood leukocytes. The sequencing of candidate genes was performed to screen out the disease-causing mutation. The effects of amino acid changes on the structure of proteins were predicted by bioinformatics analysis. Affected individuals presented lamellar lens opacities and myopia. Direct sequencing revealed a heterozygous c. 34 C>T variation in the αA-crystallin protein (CRYAA) gene, which resulted in the replacement of a highly conserved arginine by cystine at codon 12 (p.R12C). This mutation co-segregated with all affected individuals and was not observed in unaffected members or the 100 normal controls. Bioinformatic analysis showed that a highly conserved region was located around Arg12, an increase in local hydrophobicity was shown around the substitution site and the secondary structure of the mutant CRYAA protein has been changed. This is the case of a congenital lamellar cataract phenotype with myopia associated with the mutation of Arg12Cys (p.R12C) in CRYAA. Our finding confirms the high rate of mutations at this dinucleotide. In addition, these results demonstrate a myopia susceptibility locus in this region, which might also be associated with the mutation in CRYAA.
The mechanism of hsa-miR-424-5 combining PD-1 through mTORC signaling pathway to stimulate immune effect and participate in Type 1 diabetes
Authors: Wang Guofeng , Yan Yongxin , Zheng Zhichen , Zhang Tongyu
Published: February 2020

In the present study, hsa-miR-424-5p mimic plasmid and hsa-mir-424-5p inhibitor plasmid were designed and injected into rats respectively, and miRNA control plasmid was also constructed. Models of Type 1 diabetes (T1D) were built. After successful modeling, the expression of hsa-miR-424-5p in lymphocytes was analyzed by RT-PCR. The expression of protein PD-1, T-bet, CXCR3, STING in Th1 lymphocytes and content of IGF-1 in islet tissue were analyzed by flow analysis. The protein levels of SHP2, Rheb, mTORC1, Rictor and Raptor in islet tissue were analyzed by Western blot. The results showed that hsa-miR-424-5p mimic group had the highest expression of hsa-miR-424-5p in lymphocytes. The expression of PD-1 was in hsa-miR-424-5p inhibitor > miRNA control > hsa-miR-424-5p mimic, while the expression of T-bet, CXCR3 and STING was in hsa-miR-424-5p mimic > miRNA control > hsa-miR-424-5p inhibitor. The expression of IGF-1 protein in hsa-miR-424-5p inhibitor group was the highest (32.08%) and hardly expressed in hsa-miR-424-5p mimic group (2.36%). The expression of SHP2, Rheb, mTORC1, Rictor and Raptor of insulin histoproteins were in hsa-miR-424-5p mimic group > miRNA control of > hsa-miR-424-5p inhibitor group, with statistical differences. It indicates that hsa-miR-424-5p binding PD-1 signaling molecules can stimulate the immune effect through the mTORC signaling pathway and participates in the pathogenesis of T1D.
Balancing scheme for phase current and flying‐capacitor voltage in three‐level DC–DC converter
Authors: Choi Minho , Kye Chan‐Ho , Jeong Deog‐Kyoon
Published: February 2020

A balancing scheme for phase current and voltage of the flying capacitor in a fully integrated multi‐level multi‐phase DC–DC converter is proposed. The proposed balancing scheme based on the ripple voltage of the flying capacitor can simultaneously mitigate the imbalance of phase current and voltage of the flying capacitor. A mathematical analysis shows the proposed scheme can obtain the current information of the flying capacitor during charging and discharging operations and finally obtain the average inductor‐current value. A prototype 4‐phase 350 MHz three‐level DC–DC converter shows <4.7% voltage imbalance of the flying capacitor and <36 mA phase‐current imbalance at output voltage and maximum load current of 0.9 V and 1.2 A, respectively.
Quadrature spatial modulation based multiuser MIMO transmission system
Authors: Castillo‐Soria Francisco Ruben , Basar Ertugrul , Cortez Joaquín , Cardenas‐Juarez Marco
Published: February 2020

This study presents a multiuser (MU) multiple‐input multiple‐output (MIMO) downlink transmission scheme based on the quadrature spatial modulation (QSM) concept, which uses the indices of the non‐zero entries in its transmission vector to modulate and transmit an independent sequence of bits for each user in the system. The MU interference is removed by using a matrix precoding technique based on channel state information (CSI) known as block diagonalisation (BD). The performance of the proposed scheme is compared with the conventional MU–MIMO–BD system for uncorrelated Rayleigh fading channels and correlated fading channels with imperfect CSI in the reception. Additionally, a low‐complexity near maximum likelihood (ML) detection algorithm for the MU–MIMO–QSM signal's detection is proposed. For the considered cases, the proposed MU–MIMO–QSM scheme exhibits gains up to 1 dB in bit error rate performance and a reduction in detection complexity up to 93% as compared to the conventional MU–MIMO–BD scheme for the optimal ML detection. The proposed algorithm performs very near to the optimal ML detector whilst achieving a complexity reduction of up to 58%.
On ASER performance of higher order QAM schemes in two‐way multiple‐relay networks under imperfect CSI
Authors: Kumar Nagendra , Singya Praveen Kumar , Bhatia Vimal
Published: February 2020

In this study, the authors present an analytical approach to evaluate the performance of a two‐way multi‐relay system with direct link using a three‐phase analogue network coding and opportunistic relay selection scheme. Herein, the imperfect channel state information is considered over independent and non‐identically distributed Nakagami‐m fading channels with integer‐valued fading parameter. For analysis, initially, the closed‐form expressions of cumulative distribution function and moment generating function (MGF) for the considered system are derived. Further, by using the MGF‐based approach, generalised expressions of average symbol error rate (ASER) for higher‐order quadrature amplitude modulation (QAM) schemes such as hexagonal QAM, rectangular QAM, and cross QAM are derived. They then analyse the asymptotic behaviour of ASER expression to evaluate the system's diversity order. Furthermore, a comparative analysis of the ASER performance for various QAM constellations is illustrated and impact of the number of relays, fading parameter, relay location, and channel estimation error are highlighted on the system's performance. Finally, all the analytical results are validated through Monte‐Carlo simulations.
Efficient differential signalling with reduced background radiation for multiple aperture FSO communication systems
Authors: Karimi Mohammad , Sadough Seyed Mohammad Sajad , Torabi Mohammad
Published: February 2020

The main objective of this study consists in reducing the correlated background radiations along with minimising the bit error rate (BER) for a multiple aperture free‐space optical (FSO) communication system based on differential signalling scheme. Instead of performing the conventional equal gain combining (EGC) of the two wavelengths, here, the authors propose to efficiently combine them at the receiver by using non‐equal channel‐dependent weighting factors. To this aim, they first derive the analytic expression of the BER of the considered system, which is necessary for optimising the background radiations. Second, by considering ON–OFF keying modulation, they optimise the decision threshold and the weighting factors of the two wavelength by minimising the BER. The performance merit of the proposed scheme is contrasted to the zero threshold scheme and to the EGC scheme in terms of the average BER, the average signal‐to‐noise ratio (SNR) and the background rejection at the receiver. They show that the proposed scheme can improve the SNR up to 17 dB, based on the correlation coefficient of the background radiations at two wavelengths. Moreover, simulation results confirm the superiority of the proposed scheme in terms of achievable BER compared to the aforementioned conventional methods.
Massive MIMO CSI reconstruction using CNN‐LSTM and attention mechanism
Authors: Zhang Zufan , Zheng Yue , Gan Chenquan , Zhu Qingyi
Published: February 2020

In massive multiple‐input multiple‐output (MIMO) systems, the channel state information (CSI) feedback enables performance gain in frequency division duplex networks. However, with the increase in the number of antennas, the feedback overhead of CSI will also enhance. To this end, this study addresses the issue of massive MIMO CSI reconstruction using convolutional neural network (CNN), long short‐term memory (LSTM) and attention mechanism, and proposes an efficient network architecture (denoted as CNN‐LSTM‐A). To achieve a compromise between performance and complexity, the proposed method significantly reduces the number of training parameters by utilising a single‐stage network rather than a multiple‐stage network. Finally, simulation results show that the authors method can reduce the feedback overhead of CSI effectively, and achieves better performance in terms of CSI compression and recovery accuracy compared with existing state‐of‐the‐art methods.
The MUSE-Faint survey
Authors: Zoutendijk Sebastiaan L. , Brinchmann Jarle , Boogaard Leindert A. , Gunawardhana Madusha L. P. , Husser Tim-Oliver , Kamann Sebastian , Ramos Padilla Andrés Felipe , Roth Martin M. , Bacon Roland , den Brok Mark , Dreizler Stefan , Krajnović Davor
Published: February 2020

Aims. It has been shown that the ultra-faint dwarf galaxy Eridanus 2 may host a stellar cluster in its centre. If this cluster is shown to exist, it can be used to set constraints on the mass and abundance of massive astrophysical compact halo objects (MACHOs) as a form of dark matter. Previous research has shown promising expectations in the mass range of 10−100 M⊙, but lacked spectroscopic measurements of the cluster. We aim to provide spectroscopic evidence regarding the nature of the putative star cluster in Eridanus 2 and to place constraints on MACHOs as a constituent of dark matter.

Methods. We present spectroscopic observations of the central square arcminute of Eridanus 2 from MUSE-Faint, a survey of ultra-faint dwarf galaxies with the Multi Unit Spectroscopic Explorer on the Very Large Telescope. We derived line-of-sight velocities for possible member stars of the putative cluster and for stars in the centre of Eridanus 2. We discuss the existence of the cluster and determine new constraints for MACHOs using the Fokker–Planck diffusion approximation.

Results. Out of 182 extracted spectra, we identify 26 member stars of Eridanus 2, seven of which are possible cluster members. We find intrinsic mean line-of-sight velocities of 79.7+3.1−3.8 km s−1 and 76.0+3.2−3.7 km s−1 for the cluster and the bulk of Eridanus 2, respectively, as well as intrinsic velocity dispersions of < 7.6 km s−1 (68% upper limit) and 10.3+3.9−3.2 km s−1, respectively. This indicates that the cluster most likely exists as a distinct dynamical population hosted by Eridanus 2 and that it does not have a surplus of dark matter over the background distribution. Among the member stars in the bulk of Eridanus 2, we find possible carbon stars, alluding to the existence of an intermediate-age population. We derived constraints on the fraction of dark matter that can consist of MACHOs with a given mass between 1 and 105 M⊙. For dark matter consisting purely of MACHOs, the mass of the MACHOs must be less than ∼7.6 M⊙ and ∼44 M⊙ at a 68- and 95% confidence level, respectively.
Reactivity of formic acid (HCOOH) with H atoms on cold surfaces of interstellar interest
Authors: Chaabouni Henda , Baouche Saoud , Diana Stephan , Minissale Marco
Published: February 2020

Context. Formic acid (HCOOH) is the simplest organic carboxylic acid in chemical synthesis and the significant species in interstellar chemistry. HCOOH has been abundantly detected in interstellar ices, dense molecular clouds and star-forming regions.

Aims. Laboratory hydrogenation experiments of HCOOH molecules with H atoms were performed with two cryogenic ultra-high vacuum devices on amorphous solid water ices, and highly oriented pyrolytic graphite surfaces. The aim of this work is to study the reactivity of HCOOH molecules with H atoms at low surface temperature 10 K, low surface coverage of one monolayer to three layers, and low H-atom flux of about 3.0 × 1012 molecule cm−2 s−1.

Methods. HCOOH and H beams were deposited on cold surfaces held at 10 K, and the condensed films were analyzed by in-situ Reflection Absorption InfraRed Spectroscopy and temperature programmed desorption (TPD) mass spectrometry technique by heating the sample from 10 to 200 K.

Results. Using the temperature programmed during exposure desorption technique, we highlight the possible dimerization of HCOOH molecules at low surface temperatures between 10 and 100 K. In our HCOOH+H experiments, we evaluated a consumption of 20–30% of formic acid by comparing the TPD curves at m/z 46 of pure and H-exposed HCOOH ice.

Conclusions. The hydrogenation HCOOH+H reaction is efficient at low surface temperatures. The main products identified experimentally are carbon dioxide (CO2) and water (H2O) molecules. CO bearing species CH3OH, and H2CO are also detected mainly on graphite surfaces. A chemical surface reaction route for the HCOOH+H system is proposed to explain the product formation.
Impact of vertical gas accretion on the carbon-to-oxygen ratio of gas giant atmospheres
Authors: Cridland Alexander J. , Bosman Arthur D. , van Dishoeck Ewine F.
Published: February 2020

Recent theoretical, numerical, and observational works have suggested that when a growing planet opens a gap in its disk the flow of gas into the gap is dominated by gas falling vertically from a height of at least one gas scale height. Our primary objective is to include, for the first time, the chemical impact that accreting gas above the midplane will have on the resulting carbon-to-oxygen ratio (C/O). We compute the accretion of gas onto planetary cores beginning at different disk radii and track the chemical composition of the gas and small icy grains to predict the resulting C/O in their atmospheres. In our model, all of the planets which began their evolution inward of 60 AU open a gap in the gas disk, and hence are chemically affected by the vertically accreting gas. Two important conclusions follow from this vertical flow: (1) more oxygen-rich icy dust grains become available for accretion onto the planetary atmosphere; (2) the chemical composition of the gas dominates the final C/O of planets in the inner (<20 AU) part of the disk. This implies that with the launch of theJames WebbSpace Telescope we can trace the disk material that sets the chemical composition of exoplanetary atmospheres.