bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Differences in Metabolic Activity of Melanoma Models on Response to Lonidamine plus Doxorubicin
Authors: Nath Kavindra , Roman Jeffrey , Nelson David S. , Guo Lili , Lee Seung-Cheol , Orlovskiy Stepan , Muriuki Kevin , Heitjan Daniel F. , Pickup Stephen , Leeper Dennis B. , Blair Ian A. , Putt Mary E. , Glickson Jerry D.
Published: September 2018

Lonidamine (LND), a metabolic modulator, sensitizes DB-1 human melanoma to doxorubicin (DOX) chemotherapy by acidifying and de-energizing the tumor. This report compares the effects of LND on two human melanoma lines, DB-1 and WM983B, which exhibit different metabolic properties. Using liquid chromatography mass spectrometry and Seahorse analysis, we show that DB-1 was more glycolytic than WM983B in vitro. 31P magnetic resonance spectroscopy (MRS) indicates that LND (100 mg/kg, i.p.) induces similar selective acidification and de-energization of WM983B xenografts in immunosuppressed mice. Over three hours, intracellular pH (pHi) of WM983B decreased from 6.91 ± 0.03 to 6.59 ± 0.10 (p = 0.03), whereas extracellular pH (pHe) of this tumor changed from 7.03 ± 0.05 to 6.89 ± 0.06 (p = 0.19). A decline in bioenergetics (β-NTP/Pi) of 55 ± 5.0% (p = 0.03) accompanied the decline in pHi of WM983B. Using 1H MRS with a selective multiquantum pulse sequence and Hadamard localization, we show that LND induced a significant increase in tumor lactate levels (p < 0.01). LND pre-treatment followed by DOX (10 mg/kg, i.v.) produced a growth delay of 13.7 days in WM983B (p < 0.01 versus control), a growth delay significantly smaller than the 25.4 days that occurred with DB-1 (p = 0.03 versus WM983B). Differences in relative levels of glycolysis may produce differential therapeutic responses of DB-1 and WM983B melanomas.
A novel system-level approach using RNA-sequencing data identifies miR-30-5p and miR-142a-5p as key regulators of apoptosis in myocardial infarction
Authors: Kim Jin Ock , Park Jei Hyoung , Kim Taeyong , Hong Seong Eui , Lee Ji Young , Nho Kyoung Jin , Cho Chunghee , Kim Yong Sook , Kang Wan Seok , Ahn Youngkeun , Kim Do Han
Published: September 2018

This study identified microRNAs involved in myocardial infarction (MI) through a novel system-level approach using RNA sequencing data in an MI mouse model. This approach involved the extraction of DEGs and DEmiRs from RNA-seq data in sham and MI samples and the subsequent selection of two miRNAs: miR-30-5p (family) and miR-142a-5p, which were downregulated and upregulated in MI, respectively. Gene Set Enrichment Analysis (GSEA) using the predicted targets of the two miRNAs suggested that apoptosis is an essential gene ontology (GO)-associated term. In vitro functional assays using neonatal rat ventricular myocytes (NRVMs) demonstrated that miR-30-5p is anti-apoptotic and miR-142a-5p is pro-apoptotic. Luciferase assays showed that the apoptotic genes, Picalm and Skil, and the anti-apoptotic genes, Ghr and Kitl, are direct targets of miR-30-5p and miR-142a-5p, respectively. siRNA studies verified the results of the luciferase assays for target validation. The results of the system-level high throughput approach identified a pair of functionally antagonistic miRNAs and their targets in MI. This study provides an in-depth analysis of the role of miRNAs in the pathogenesis of MI which could lead to the development of therapeutic tools. The system-level approach could be used to identify miRNAs involved in variety of other diseases.
Autophagy and Akt in the protective effect of erythropoietin helix B surface peptide against hepatic ischaemia/reperfusion injury in mice
Authors: Tan Rumeng , Tian Hongzhe , Yang Bo , Zhang Bo , Dai Chen , Han Zhenyi , Wang Meixi , Li Yakun , Wei Lai , Chen Dong , Wang Guangyao , Yang Huifang , He Fan , Chen Zhishui
Published: September 2018

Helix B surface peptide (HBSP) is an erythropoietin (EPO)-derived peptide that protects tissue from the risks of elevated blood pressure and thrombosis. This study focused on the protection of HBSP in hepatic ischaemia/reperfusion (I/R) by enhancing the level of autophagy. In detail, we randomly divided C57BL/6 mice into sham-operated, hepatic ischaemia/reperfusion (I/R), I/R + HBSP, I/R + HBSP + 3-methyladenine (autophagy inhibitor), I/R + HBSP + rapamycin (mTOR inhibitor), and I/R + HBSP + Ly294002 (Akt inhibitor) groups. We assessed alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in mouse sera, and performed haematoxylin/eosin (HE) staining, immunohistochemistry, electron microscopy, immunofluorescence microscopy, and western blotting on liver tissue to detect the degree of liver injury, liver apoptosis, autophagy, and the expression of microtubule associated protein 1 light chain 3 alpha (Map1lc3, or LC3), Beclin 1, phospho-mTOR, mTOR, phospho-Akt (P-Akt), and Akt. HBSP relieved hepatic I/R injury in a concentration-independent manner. The expression of LC3II, LC3I, and Beclin 1, and the formation of autophagosomes, in the I/R + HBSP group were higher than those in the I/R group. The protective effects of HBSP were abolished by 3-methyladenine and, to a lesser extent, Ly294002, but enhanced by rapamycin. Furthermore, In vivo, HBSP also protected against hypoxia injury induced by cobalt chloride (CoCl2) through improving the level of autophagy. Therefore, HBSP protected against hepatic I/R injury, mainly via regulating autophagy by targeting mTOR.
Bridging of membrane surfaces by annexin A2
Authors: Grill David , Matos Anna L. L. , de Vries Wilke C. , Kudruk Sergej , Heflik Milena , Dörner Wolfgang , Mootz Henning D. , Jan Ravoo Bart , Galla Hans-Joachim , Gerke Volker
Published: September 2018

The protein-mediated formation of membrane contacts is a crucial event in many cellular processes ranging from the establishment of organelle contacts to the docking of vesicles to a target membrane. Annexins are Ca2+ regulated membrane-binding proteins implicated in providing such membrane contacts; however, the molecular basis of membrane bridging by annexins is not fully understood. We addressed this central question using annexin A2 (AnxA2) that functions in secretory vesicle exocytosis possibly by providing membrane bridges. By quantitatively analyzing membrane contact formation using a novel assay based on quartz crystal microbalance recordings, we show that monomeric AnxA2 can bridge membrane surfaces Ca2+ dependently. However, this activity depends on an oxidative crosslink involving a cysteine residue in the N-terminal domain and thus formation of disulfide-linked dimers. Alkylated AnxA2 in which this cysteine residue has been modified and AnxA2 mutants lacking the N-terminal domain are not capable of bridging membrane surfaces. In contrast, a heterotetrameric complex comprising two membrane binding AnxA2 subunits linked by a S100A10 dimer can provide membrane contacts irrespective of oxidation status. Thus, monomeric AnxA2 only contains one lipid binding site and AnxA2-mediated linking of membrane surfaces under non-oxidative intracellular conditions most likely requires AnxA2-S100 complex formation.
Drug screening of biopsy-derived spheroids using a self-generated microfluidic concentration gradient
Authors: Mulholland Theresa , McAllister Milly , Patek Samantha , Flint David , Underwood Mark , Sim Alexander , Edwards Joanne , Zagnoni Michele
Published: September 2018

Performing drug screening of tissue derived from cancer patient biopsies using physiologically relevant 3D tumour models presents challenges due to the limited amount of available cell material. Here, we present a microfluidic platform that enables drug screening of cancer cell-enriched multicellular spheroids derived from tumour biopsies, allowing extensive anticancer compound screening prior to treatment. This technology was validated using cell lines and then used to screen primary human prostate cancer cells, grown in 3D as a heterogeneous culture from biopsy-derived tissue. The technology enabled the formation of repeatable drug concentration gradients across an array of spheroids without external fluid actuation, delivering simultaneously a range of drug concentrations to multiple sized spheroids, as well as replicates for each concentration. As proof-of-concept screening, spheroids were generated from two patient biopsies and a panel of standard-of-care compounds for prostate cancer were tested. Brightfield and fluorescence images were analysed to provide readouts of spheroid growth and health, as well as drug efficacy over time. Overall, this technology could prove a useful tool for personalised medicine and future drug development, with the potential to provide cost- and time-reduction in the healthcare delivery.
Direct Photochemical C–H Carboxylation of Aromatic Diamines with CO2 under Electron-Donor- and Base-free Conditions
Authors: Matsumoto Takeshi , Uchijo Daiki , Koike Takuji , Namiki Ryoya , Chang Ho-Chol
Published: September 2018

We report the photochemical carboxylation of o-phenylenedimamine in the absence of a base and an electron donor under an atmosphere of CO2, which afforded 2,3-diaminobenzoic acid (DBA) in 28% synthetic yield and 0.22% quantum yield (Φ(%)). The synthetic yield of DBA in this reaction increased to 58% (Φ(%) = 0.47) in the presence of Fe(II). The photochemical reaction described in this work provides an effective strategy to use light as the driving force for the direct carboxylation of organic molecules by CO2.
Synthesis and Evaluation of Herbal Chitosan from Ganoderma Lucidum Spore Powder for Biomedical Applications
Authors: Zhu Li-Fang , Yao Zhi-Cheng , Ahmad Zeeshan , Li Jing-Song , Chang Ming-Wei
Published: September 2018

Chitosan is an extremely valuable biopolymer and is usually obtained as a byproduct from the shells of crustaceans. In the current work, chitosan is obtained from an herbal source (Ganoderma lucidum spore powder (GLSP)) for the first time. To show this, both standard (thermochemical deacetylation, (TCD)) and emerging (ultrasound-assisted deacetylation (USAD)) methods of chitosan preparation were used. The obtained chitosan was characterized by elemental analysis, XRD (X-ray diffraction), FT-IR (Fourier transform infrared spectroscopy) and thermogravimetric measurements. The process resulted in chitosan possessing comparable values of DD, [η] and $$\,\overline{{\rm{Mv}}}$$

Mv

¯

to the commercial product. Chitosan obtained via both processes (TCD and USAD) displayed excellent biocompatibility; although the USAD prepared biopolymer exhibited significantly improved fibroblast (L929 cell) viability and enhanced antibacterial zones for both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The findings of new herbal chitosan mark key developments of natural biomaterials; marking a potential shift from conventional sea-based organisms.
Determination of phospholipid and fatty glyceride in liposome by RP-HPLC with capacitively coupled contactless conductivity detector
Authors: Huang Xing , Zhang Kaipeng , Tong Yanli , Zhong Yongsheng , Chen Zuanguang
Published: September 2018

In this study, a gradient RP-HPLC with capacitively coupled contactless conductivity detection (RP-HPLC-C4D) method for simultaneous determination of phospholipid and fatty glyceride in liposome was developed.
Encoding function into polypeptide-oligonucleotide precision biopolymers
Authors: Liu Weina , Boldt Felix , Tokura Yu , Wang Tao , Agrawalla Bikram Keshari , Wu Yuzhou , Weil Tanja
Published: September 2018

We report a novel synthesis strategy to prepare precision polymers providing exact chain lengths, molecular weights and monomer sequences that allow post modifications by convenient DNA hybridization.
Mn–Fe layered double hydroxide nanosheets: a new photothermal nanocarrier for O2-evolving phototherapy
Authors: Ruan Yudi , Jia Xiaodai , Wang Chao , Zhen Wenyao , Jiang Xiue
Published: September 2018

Iron–manganese layered double hydroxide nanosheets were developed as an effective photothermal nanocarrier for loading a photosensitizer.
Exogenous-oxidant-free electrochemical oxidative C–H sulfonylation of arenes/heteroarenes with hydrogen evolution
Authors: Yuan Yong , Yu Yi , Qiao Jin , Liu Pan , Yu Banying , Zhang Wukun , Liu Huilin , He Min , Huang Zhiliang , Lei Aiwen
Published: September 2018

This work describes an exogenous-oxidant-free radical C–H sulfonylation using an electrochemical oxidative protocol.
Methanol as hydrogen source: transfer hydrogenation of aromatic aldehydes with a rhodacycle
Authors: Aboo Ahmed H. , Bennett Elliot L. , Deeprose Mark , Robertson Craig M. , Iggo Jonathan A. , Xiao Jianliang
Published: September 2018

A rhodacycle catalyses efficient hydrogenation of aldehydes, deriving the hydrogen from methanol.
Rh(iii)-Catalyzed ortho-C-(sp2)–H amidation of ketones and aldehydes under synergistic ligand-accelerated catalysis
Authors: Hande Akshay Ekanath , Ramesh Vinay Bapu , Prabhu Kandikere Ramaiah
Published: September 2018

Rh(iii)-Catalyzed ortho-C–H amidation of ketones and aldehydes under cooperative metal organocatalysis has been utilized for synthesizing various ortho-amidocarbonyl analogs, and the reaction for the aldehyde proceeds >at ambient temperature.
1,4-Conjugate addition/esterification of ortho-quinone methides in a multicomponent reaction
Authors: Chen Renjie , Liu Yu , Cui Sunliang
Published: September 2018

A novel 1,4-conjugate addition/esterification of ortho-quinone methides in a multicomponent reaction has been developed for facilely accessing 3,3-diarylpropanamides.
Evaluation of the formation and carbon dioxide capture by Li4SiO4 using in situ synchrotron powder X-ray diffraction studies
Authors: Grasso M. L. , Blanco M. V. , Cova F. , González J. A. , Arneodo Larochette P. , Gennari F. C.
Published: September 2018

The formation pathway of Li4SiO4 involves Li2SiO3 as an intermediate. Carbonation of Li4SiO4 under dynamical conditions retards the double shell formation, improving CO2 capture capacity.
Monte Carlo simulation on the dynamics of a semi-flexible polymer in the presence of nanoparticles
Authors: Peng Yi , Zhang Huan , Huang Xiao-Wei , Huang Jian-Hua , Luo Meng-Bo
Published: September 2018

Polymer dynamics vary non-monotonically with chain stiffness at strong polymer–nanoparticle attraction: stiff polymers can move faster than flexible ones.
Rate exchange rather than relaxation controls structural recovery
Authors: Riechers Birte , Richert Ranko
Published: September 2018

Observing frequency invariant aging dynamics suggests that the homogeneous process of rate exchange rather than heterogeneous relaxation governs structural recovery.
The low temperature D+ + H2 → HD + H+ reaction rate coefficient: a ring polymer molecular dynamics and quasi-classical trajectory study
Authors: Bhowmick Somnath , Bossion Duncan , Scribano Yohann , Suleimanov Yury V.
Published: September 2018

The D+ + H2 → HD + H+ reaction rate coefficient has been calculated at low temperatures (20–100 K) by ring polymer molecular dynamics and quasi-classical trajectory methods.
A sulphur and uranium fiesta! Synthesis, structure, and characterization of neutral terminal uranium(vi) monosulphide, uranium(vi) η2-disulphide, and uranium(iv) phosphine sulphide complexes
Authors: Pagano Justin K. , Arney David S. J. , Scott Brian L. , Morris David E. , Kiplinger Jaqueline L. , Burns Carol J.
Published: September 2018

Three new uranium species, (C5Me5)2U(N-2,6-iPr2-C6H3)(S), (C5Me5)2U(N-2,6-iPr2-C6H3)(η2-S2), and (C5Me5)2U(N-2,6-iPr2-C6H3)(SPMe3) have been prepared.
Post-synthetic modification of zirconium metal–organic frameworks by catalyst-free aza-Michael additions
Authors: Amer Hamzah Harina , Crickmore Tom S. , Rixson Daniel , Burrows Andrew D.
Published: September 2018

UiO-66-NH2 reacts with acrylonitrile, acrylic acid, methyl acrylate and methyl vinyl ketone leading to post-synthetic modification of the MOF through C–N bond formation. The acrylonitrile-modified MOF undergoes further reaction to form a tetrazolate-modified MOF.
Influence of the sublayer structure of thin-film composite reverse osmosis membranes on the overall water flux
Authors: Lee Jaewoo , Yoon Hongsik , Yoo Jae Hyun , Choi Dong-Chan , Nahm Chang H. , Lee Sang Hyun , Chae Hee-Ro , Kim Yong Hyup , Lee Chung-Hak , Park Pyung-Kyu
Published: September 2018

The support layer of RO membranes can significantly affect the permeability depending on its sublayer structure.
Parallel anti-sense two-step cascade for alcohol amination leading to ω-amino fatty acids and α,ω-diamines
Authors: Sung Sihyong , Jeon Hyunwoo , Sarak Sharad , Ahsan Md Murshidul , Patil Mahesh D. , Kroutil Wolfgang , Kim Byung-Gee , Yun Hyungdon
Published: September 2018

A novel ‘parallel anti-sense’ cascade, employing aldehyde reductase and ω-transaminase, has been reported to produce bioplastic monomers with excellent conversion.
A poly(3-hydroxybutyrate)–chitosan polymer conjugate for the synthesis of safer gold nanoparticles and their applications
Authors: Silvestri Daniele , Wacławek Stanisław , Sobel Bartłomiej , Torres-Mendieta Rafael , Novotný Vít , Nguyen Nhung H. A. , Ševců Alena , Padil Vinod V. T. , Müllerová Jana , Stuchlík Martin , Papini Marco Petrangeli , Černík Miroslav , Varma Rajender S.
Published: September 2018

The solvation of polyhydroxybutyrate in water was attained by conjugation with chitosan.
A critical review on isotopic fractionation correction methods for accurate isotope amount ratio measurements by MC-ICP-MS
Authors: Yang Lu , Tong Shuoyun , Zhou Lian , Hu Zhaochu , Mester Zoltán , Meija Juris
Published: September 2018

Proper correction of mass-dependent and mass-independent isotopic fractionation is crucial to obtain accurate isotope amount ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS).
H.E.R.M.E.S: rapid blood-plasma separation at the point-of-need
Authors: Vemulapati Sasank , Erickson David
Published: September 2018

We demonstrate H.E.R.M.E.S, a novel magnetic-bead based method to perform rapid blood-plasma separation at the point of need that can augment the performance of present-day diagnostic testing platforms.
Zn(ii)–nucleobase metal–organic nanofibers and nanoflowers: synthesis and photocatalytic application
Authors: Sharma Bhagwati , Mahata Arup , Mandani Sonam , Thakur Neha , Pathak Biswarup , Sarma Tridib K.
Published: September 2018

The interaction of Zn2+ ions with pure nucleobases guanine and cytosine under alkaline conditions leads to the formation of nanoscale metal–organic nanofibers and nanoflowers with excellent photocatalytic activity for the degradation of organic pollutant dyes.
A novel photosensitizer based on a ruthenium(ii) phenanthroline bis(perylenediimide) dyad: synthesis, generation of singlet oxygen andin vitrophotodynamic therapy
Authors: Aksakal Nuray Esra , Kazan Hasan Hüseyin , Eçik Esra Tanrıverdi , Yuksel Fatma
Published: September 2018

In this study, a novel photosensitizer having two perylenediimide units and a phenanthroline ruthenium(ii) coordination moiety (Ru-BP)has been developed for photodynamic therapy (PDT) of cancer cells.
Naked-eye and ratiometric fluorescence probe for fast and sensitive detection of hydrogen sulfide and its application in bioimaging
Authors: Ma Jianlong , Li Feifei , Li Qiang , Li Yijing , Yan Chaoxian , Lu Xiaofeng , Guo Yong
Published: September 2018

A sensitive and ultrafast ratiometric fluorescence probe for the detection of hydrogen sulfide (H2S) in HeLa cells and zebrafish.
Distinct roles of SNARE-mimicking lipopeptides during initial steps of membrane fusion
Authors: Koukalová Alena , Pokorná Šárka , Boyle Aimee L. , Lopez Mora Nestor , Kros Alexander , Hof Martin , Šachl Radek
Published: September 2018

A molecular explanation is provided which clarifies the regulatory mechanism by which lipopeptide mediated membrane fusion occurs.
Correction: Solid-state nanopore analysis on conformation change of p53TAD–MDM2 fusion protein induced by protein–protein interaction
Authors: Chae Hongsik , Kwak Dong-Kyu , Lee Mi-Kyung , Chi Seung-Wook , Kim Ki-Bum
Published: September 2018

Correction for ‘Solid-state nanopore analysis on conformation change of p53TAD–MDM2 fusion protein induced by protein–protein interaction’ by Hongsik Chae et al., Nanoscale, 2018, DOI: 10.1039/c8nr06423g.
Functionalization of boron-doped diamond with a push–pull chromophore via Sonogashira and CuAAC chemistry
Authors: Raymakers Jorne , Krysova Hana , Artemenko Anna , Čermák Jan , Nicley Shannon S. , Verstappen Pieter , Gielen Sam , Kromka Alexander , Haenen Ken , Kavan Ladislav , Maes Wouter , Rezek Bohuslav
Published: September 2018

Functionalization of boron-doped diamond with a push–pull chromophore via Sonogashira cross-coupling affords better photovoltaic performances as compared to functionalization via CuAAC.
Effect of organic and inorganic ions on the lower critical solution transition and aggregation of PNIPAM
Authors: Pérez-Fuentes Leonor , Bastos-González Delfi , Faraudo Jordi , Drummond Carlos
Published: September 2018

We have studied the effect of different ions belonging to the extended Hofmeister series on the thermosensitive polymer poly(N-isopropylacrylamide) (PNIPAM), by combining Differential Scanning Calorimetry (DSC) and Dynamic Light Scattering (DLS).
Electrochemical polymerization for two-dimensional conjugated polymers
Authors: Zhang Qing , Dong Huanli , Hu Wenping
Published: September 2018

This article places special focus on the recent research progress of the EP method in synthesizing CPs. In particular, their potential applications as 2D CPs are summarized, with a basic introduction of the EP method, its use in synthesizing CPs as well as the promising applications of the obtained CPs in different fields. Discussions of current challenges in this field and future research directions are also given.
A stimuli responsive material of perovskite quantum dots composited nano-porous glass
Authors: Han Yuhong , Sun Jiayi , Ye Shi , Zhang Qinyuan
Published: September 2018

The water-responsive behavior of the perovskite halides composited porous glass was in situ imaged by a confocal microscope.
High-performance vertical GaN-based near-ultraviolet light-emitting diodes on Si substrates
Authors: Li Yuan , Wang Wenliang , Huang Liegen , Zheng Yulin , Li Xiaochan , Tang Xin , Xie Wentong , Chen Xiaofen , Li Guoqiang
Published: September 2018

High-performance vertical GaN-based near-ultraviolet (UV) light-emitting diodes (LEDs) on Si substrates with an electroluminescence emission wavelength of 395 nm have been fabricated by designing epitaxial structures to reduce the dislocation density and enhance the electron confinement and hole injection.
Enhanced sparse Bayesian learning‐based channel estimation with optimal pilot design for massive MIMO–OFDM systems
Authors: AL‐Salih Hayder , Nakhai Mohammad Reza , Le Tuan Anh
Published: September 2018

The pilot contamination problem creates a limitation to the potential benefits of massive multiple input multiple output (MIMO) systems. To mitigate the pilot contamination, in this study, the authors propose a novel channel estimation for massive MIMO systems, using sparse Bayesian learning (SBL) based on a pattern‐coupled hierarchical Gaussian framework. In the proposed technique, the sparsity of each channel coefficient is controlled by its own hyperparameter and the hyperparameters of its immediate neighbours. The simulation results show that the channel coefficients can be estimated more efficiently in contrast to the conventional channel estimators in terms of channel estimation with pilot contamination. Furthermore, they derive the mean square error (MSE) analytical expression for the proposed technique and based on that MSE expression, a pilot design criterion is proposed to design the optimal pilot to improve the estimation accuracy of the proposed algorithm using the Lagrange multiplier optimisation method. Results show that they can reduce the MSE of the SBL estimator by employing the optimal pilot sequence.
BER performance of an MRT‐HQAM system over Rayleigh fading channels with channel estimation errors and feedback delay
Authors: Evans Adam , Quazi Tahmid , Xu Hongjun
Published: September 2018

In this study, the bit error rate (BER) performance of multiple‐input‐multiple‐output (MIMO) hierarchical quadrature amplitude modulation systems employing maximum ratio transmission (MRT‐HQAM) is investigated under the effects of imperfect channel state information (ICSI) due to the channel estimation error and feedback delay. Theoretical expressions for the BER performance of the MRT‐HQAM systems are derived using the two common ICSI models that exist in the current literature, specifically when studying the MIMO beam‐forming systems with ICSI, where the error term due to the ICSI is assumed to contribute to either the noise component or to the signal component. The BER results for the two ICSI models are presented and then compared. In addition, various antenna configurations are studied to illustrate the performance gains achievable with additional antennas, and to identify the ideal antenna configuration for a given number of antennas. Moreover, the hierarchical modulation parameter is varied to determine the varying levels of sensitivity of the hierarchical layers in the presence of ICSI. The theoretical BER expressions provided for both ICSI models are verified by simulation results.
Multiclass multistep discontinuous Galerkin discretisation for multiscale electromagnetic wave propagation simulations
Authors: Souza Fidel , Mesquita Renato C. , Silva Elson J.
Published: September 2018

The classical numerical methods for the simulation of wave propagation phenomena in multiscale systems can demand an unnecessary computational cost. This study proposes a multiclass strategy to be applied to the linear multistep time integration methods in the formalism of the discontinuous Galerkin (DG) space discretisation. The multiclass scheme is applied specifically to linear multistep strong stability preserving method (SSPMS). The potential of this strategy is demonstrated by numerical tests applied to two electromagnetic problems. The results show that the proposed schemes promote a significant improvement compared with the standard SSPMS and the fourth‐order Runge–Kutta. Furthermore, in order to obtain a real speed up, this study presents a class parameter that produces a previous knowledge to determine the number of classes.
Effects of structure and material of polluted insulators on the wetting characteristics
Authors: Yang Lin , Bi Jikai , Zhang Fei , Hao Yanpeng , Li Licheng , Liao Yifan , Zhang Fuzeng
Published: September 2018

Umbrella‐type structure, the material of insulators and surface positions influence the wetting process of polluted insulator surfaces tremendously. Using a custom‐made phase‐angle‐difference (PAD) detection device, the PAD of the different positions of different polluted insulators is measured, and the PAD curves and partial pollution surface electrical conductivity γ20 varying with time are plotted. The results show that there is a certain difference in the wetting characteristics of different positions. The saturated wetting time of different positions of LXAY‐70 insulators is 12.5–15 min; that for LXHY5‐70 insulators is 12–25 min; that for XWP2‐70 insulators is 8–14 min; and that for FXBW‐10/70 insulators is 18–26.5 min. The umbrella‐type structure is shown to have a direct effect on the wetting process of polluted insulators. The complicated umbrella‐type structure, especially the existence of umbrella ribs, causes an uneven degree of wetting between the upper and lower surfaces, and leads to the increase of the difference in wetting state between the different positions. Furthermore, there is a certain difference in the wetting speed of insulators comprised of different materials. Hydrophilic porcelain and glass insulators are more easily wetted than composite insulators, even though the hydrophobicity class of composite insulators is 7.
Understanding the influence of ambience on thermal ageing of natural ester liquid
Authors: Thakur Soumya , Panigrahi Suraj Kumar , Mishra A.K. , Sarathi Ramanujam
Published: September 2018

Ambience during thermal ageing of ester liquid has a high impact on corona inception voltage (CIV) under AC and DC voltages. The CIV is high with ester liquid thermally aged in nitrogen ambience and is the least with air aged. CIV is high under negative DC voltage followed by positive DC and AC voltages. CIV reduces with increase in harmonic voltage and the reduction is predominant with harmonic voltages with higher total harmonic distortions. Corona activity radiates ultra‐high‐frequency (UHF) signal with its dominant frequency at 1 GHz. Phase‐resolved partial discharge analysis carried out using UHF signal indicates that corona discharges occur at the peak of the voltage waveform. The magnitude of discharges is less in thermally aged liquid but the number of discharges increases. Fourier transform infrared spectroscopy analysis indicates the formation of carbonaceous particles with thermal ageing. Thermal ageing of ester liquid causes to form new chromophoric moieties causing red shift of absorption band in ultraviolet–visible spectra. Fluorescence spectroscopy traces the characteristic variations due to thermal ageing, which can be adopted for condition monitoring.
Comparing frequency‐dependent and distributed parameter with lumped losses power cable line models for cable insulation coordination against overvoltages
Authors: Marzinotto Massimo , Pelliccione Giuseppe
Published: September 2018

Simulations of transients are an obliged step for the insulation coordination of cable lines. Although a frequency‐dependent power cable line model better takes into account real conditions since resistive and inductive parameters vary with frequency, a distributed parameter with lumped losses power cable models can be useful to simplify and give higher flexibility to the insulation coordination study. In such a case, a dilemma rises up when a frequency shall be selected for the determination of the cable parameters. In this study, a comparative analysis between the two models has been performed considering a typical configuration layout, i.e. an overvoltage coming from an overhead line and stressing the cable line terminated on a transformer. The overvoltages stressing both cable insulation wall and cable thermoplastic jacket are evaluated using the same system configuration with both frequency‐dependent and distributed parameter with lumped losses power cable line models, in the latter case sweeping different frequency values for the determination of the cable parameters. A frequency range that minimise the differences between the overvoltage estimation using the two models is suggested.
Development of ultrahigh‐voltage standard voltage transformer based on series voltage transformer structure
Authors: Feng Zhou , Chunyang Jiang , Min Lei , Fuchang Lin , Shihai Yang
Published: September 2018

An ultrahigh‐voltage standard voltage transformer (VT) based on series voltage transformer (SVT) structure is described. A precise isolation VT is designed to realise the connection between the VTs of an SVT. Moreover, the ratio and errors of the SVT are discussed and calculated to reduce the magnetic error of the isolation VT, and capacitor compensation is proposed. Two calibration methods for the SVT are compared. The results are very approaching, and the largest differences between the two methods are <0.08 × 10−4 and 0.08 min. The results indicate that the errors of an SVT can be obtained by testing at only half the voltage of the SVT.
Prediction of drug synergy score using ensemble based differential evolution
Authors: Singh Harpreet , Rana Prashant Singh , Singh Urvinder
Published: September 2018

Prediction of drug synergy score is an ill‐posed problem. It plays an efficient role in the medical field for inhibiting specific cancer agents. An efficient regression‐based machine learning technique has an ability to minimise the drug synergy prediction errors. Therefore, in this study, an efficient machine learning technique for drug synergy prediction technique is designed by using ensemble based differential evolution (DE) for optimising the support vector machine (SVM). Because the tuning of the attributes of SVM kernel regulates the prediction precision. The ensemble based DE employs two trial vector generation techniques and two control attributes settings. The initial generation technique has the best solution and the other is without the best solution. The proposed and existing competitive machine learning techniques are applied to drug synergy data. The extensive analysis demonstrates that the proposed technique outperforms others in terms of accuracy, root mean square error and coefficient of correlation.
Switching control strategy for the HIV dynamic system with some unknown parameters
Authors: Ding Yi , Wang Wen‐June
Published: September 2018

In human immunodeficiency virus (HIV) infection, many factors may influence the counts of healthy cells, immune cells and viruses. Drug treatment design for the HIV dynamic system is a valuable subject to be studied. This study considers an HIV dynamic system model with some unknown parameters and unmeasurable CD8 + T cell count and proposes a switching control strategy to force all states of the system to achieve a healthy status. It is a switching form with two different drug therapies and is designed based on the Lyapunov function theory such that the states of the HIV system approach the health equilibrium asymptotically without the influence of unknown parameters and unmeasurable cell counts. The values of all states and drug concentrations are assured to be positive in the control process so that the control strategy can satisfy the actual treatment requirements. Finally, a numerical example is illustrated to show the effectiveness of the proposed control strategy.
Effect of annealing atmosphere on the structural and optical properties of the Nb‐doped β‐Ga2O3 films
Authors: Zhang Hao , Deng Jin‐Xiang , Kong Le , Pan Zhiwei , Bai Zhiying , Wang Jiyou
Published: September 2018

The Nb‐doped β‐Ga2O3 (β‐Ga2O3 :Nb) thin films have been deposited on the Si and quartz substrates by radio‐frequency magnetron technique in argon ambient. The effects of annealing atmosphere on the structural and optical properties of β‐Ga2O3 :Nb thin films have been investigated. The crystallinity of β‐Ga2O3 :Nb film is improved obviously after annealing. An increase in surface roughness is observed on annealed films. The bandgap from 5.19 to 5.26 eV is obtained after annealing in different atmosphere, which is larger than the 5.09 eV before annealing. Moreover, the red‐shift of photoluminescence emission peak is observed after annealing, and the annealing atmosphere has an influence on the peak intensity.
Electrostatic‐driven self‐assembled silica aerogel/tethacryloxyethyltrimethyl ammonium chloride/PMMA ternary nanocomposite with thermal insulation phase interfaces
Authors: Li Hongyan , Song Limeng , Fu Yongqiang , Sun Cong , Li Ruyi , Yang Aiwu , Liu Hongli
Published: September 2018

A three‐dimensional (3D) porous silica aerogel (SA)/tethacryloxyethyltrimethyl ammonium chloride (MTC)/polymethylmethacrylate (PMMA) (SMP) ternary nanocomposite was fabricated through electrostatic‐driven self‐assembly by in situ polymerisation. The as‐prepared products were characterised by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Zeta potential (ZETA), multi‐assay gel permeation chromatography, the synchronous thermal analyser (TG), differential scanning calorimetry and so on. The results show that the ternary hybrid aerogels have an interconnected 3D nanoporous structure with a diameter of about 20–40 nm. Furthermore, positively charged MTC was successfully absorbed on the negatively charged SiO2 aerogels surface to form high‐thermal insulation phase interfaces. The SMP hybrid aerogels revealed a favourable mechanical property and an excellent thermal insulation property. Overall, the present study introduces the static electrical phase interfaces that are physical interactions between the silica phase and the polymer phase to distinctly improve the thermal insulation property of SiO2‐based aerogels, which could become a promising insulating material for broadening applications.
Facile fabrication of TiO2@TiO2 transparent free‐standing film for photocatalysis
Authors: Zhang Shanmei , Hu Yue , Hu Luyang , Zhang Yumin , Zhou Yufeng , Li Benxia
Published: September 2018

A transparent titanium dioxide (TiO2)@TiO2 film with free‐standing structure was synthesised by employing a cellulose paper as the template. By one‐step hydrothermal method and subsequent thermal annealing, the fibre of cellulose paper was changed into porous TiO2 core layer. The flower‐like micro/nanostructure TiO2 particle layer was intimately distributed on the porous TiO2 core layer. The average diameter of the TiO2@TiO2 fibre for the film was 11 μm. The size of spherical granular TiO2 on the fibre surface was around 330 ± 130 nm. It was noted that the microtopography of fibre surface could be adjusted by tuning the hydrothermal temperature. The scanning electron microscopy and N2 adsorption–desorption measurement results indicated that the prepared film possessed a large mass of mesopores and macropores. On the basis of the special microstructure, the TiO2@TiO2 film exhibited high photocatalytic activity for methylene blue under ultraviolet irradiation. This work might provide a new insight for preparation of transparent photocatalytic film toward water purification.
Photocatalytic removal of cyanide and Cr(IV) from wastewater in the presence of each other by using TiO2/UV
Authors: Koohestani Hassan
Published: September 2018

Cyanide (CN) and chromium (VI) are hazardous, toxic pollutants whose presence in water and wastewater can seriously affect human and its environment, hence the necessity of controlling these contaminants. In this work, by using TiO2/UV, the simultaneous photocatalytic reduction of Cr(VI) and oxidation of CN in aqueous suspensions were investigated. Variations of this study were pH, pollutant concentration, and reaction time. CN and total chromium were determined by Titrimetric method, and Colourimetric method, respectively. Maximum removal of chromium and CN occurs at pH 2.3 and 10, respectively. In the binary system, the electron–hole recombination is blocked and as a result, total efficiency increases. An increase in the initial concentrations of CN and Cr(VI) led to a rise in the reduction efficiency of Cr(VI) and CN up to an optimum amount, and then it went into decline as the concentration of the pollutants increased any further. The maximum quantum efficiency of Cr(VI) photoreduction with CN being present was calculated to be 23% at room temperature. Furthermore, the kinetic experimental was investigated and it became evident that the pseudo‐first‐order kinetic model is capable of defining Cr(VI) and CN both. Finally, based on the obtained results, a TiO2 system is proposed to remove both pollutants.
Energy gap variation due to Al content in SmFe1−x Alx O3 and its application in optics
Authors: Fawzy Ahmed Mohamed , Eessaa Ashraf Kamal , Saeid Yasser A.
Published: September 2018

The optical properties of Al‐doped SmFeO3 (SmFe1−x Alx O3, for x varying from 0 to 0.15), were monitored by diffuse reflectance spectroscopy (DRS). The diffuse reflectance spectra were used to study the surface properties of the samples. The DRS spectra exhibit three reflection bands at different regions. The product was characterised by X‐ray diffraction to confirm the formation of single‐phase crystals of the perovskite structure. The bandgap, a major factor in determining the optical performance of any material, was found to be tunable with Al content (x).
Mesoporous MnO/C composite synthesised from the precursor of Mn3 (C6H5O7)2 and the application in Li‐ion batteries
Authors: Shanshan Bao , Junfeng Li , Yang Gao , Ping Li , Bo Yue , Yanjun Li , Wenxian Sun , Xuefei Lai
Published: September 2018

A facile and scalable route for the in‐situ synthesis of porous MnO/C nanocomposite by annealing Mn3 (C6H5O7)2 precursor has been developed. MnO particles were encapsulated inside the carbon matrix to form a skeletal architecture. Such a mesoporous structure provided more active sites and effective channels for Li+ and electrolyte, and act as the supporting structure for MnO particles during the cycling process. As an anode material for lithium ion batteries, the porous MnO/C composite had a specific capacity of 831.7 mAh g−1 at 100 mA g−1 and delivered a stable cycling capacity of 564.1 mAh g−1 after 59 cycles, indicating that the porous MnO/C nanocomposite could significantly improve the structural stability and might be a suitable electrode material for lithium‐ion batteries.
CARMENES input catalogue of M dwarfs
Authors: Díez Alonso E. , Caballero J. A. , Montes D. , de Cos Juez F. J. , Dreizler S. , Dubois F. , Jeffers S. V. , Lalitha S. , Naves R. , Reiners A. , Ribas I. , Vanaverbeke S. , Amado P. J. , Béjar V. J. S. , Cortés-Contreras M. , Herrero E. , Hidalgo D. , Kürster M. , Logie L. , Quirrenbach A. , Rau S. , Seifert W. , Schöfer P. , Tal-Or L.
Published: September 2018

Aims. The main goal of this work is to measure rotation periods of the M-type dwarf stars being observed by the CARMENES exoplanet survey to help distinguish radial-velocity signals produced by magnetic activity from those produced by exoplanets. Rotation periods are also fundamental for a detailed study of the relation between activity and rotation in late-type stars.

Methods. We look for significant periodic signals in 622 photometric time series of 337 bright, nearby M dwarfs obtained by long-time baseline, automated surveys (MEarth, ASAS, SuperWASP, NSVS, Catalina, ASAS-SN, K2, and HATNet) and for 20 stars which we obtained with four 0.2–0.8 m telescopes at high geographical latitudes.

Results. We present 142 rotation periods (73 new) from 0.12 d to 133 d and ten long-term activity cycles (six new) from 3.0 a to 11.5 a. We compare our determinations with those in the existing literature; we investigate the distribution of Prot in the CARMENES input catalogue, the amplitude of photometric variability, and their relation to v sini and pEW(Hα); and we identify three very active stars with new rotation periods between 0.34 d and 23.6 d.
Metallicity effect and planet mass function in pebble-based planet formation models
Authors: Brügger N. , Alibert Y. , Ataiee S. , Benz W.
Published: September 2018

Context. One of the main scenarios of planet formation is the core accretion model where a massive core forms first and then accretes a gaseous envelope. This core forms by accreting solids, either planetesimals or pebbles. A key constraint in this model is that the accretion of gas must proceed before the dissipation of the gas disc. Classical planetesimal accretion scenarios predict that the time needed to form a giant planet’s core is much longer than the time needed to dissipate the disc. This difficulty led to the development of another accretion scenario, in which cores grow by accretion of pebbles, which are much smaller and thus more easily accreted, leading to more rapid formation.

Aims. The aim of this paper is to compare our updated pebble-based planet formation model with observations, in particular the well-studied metallicity effect.

Methods. We adopt the Bitsch et al. (2015a, A&A, 575, A28) disc model and the Bitsch et al. (2015b, A&A, 582, A112) pebble model and use a population synthesis approach to compare the formed planets with observations.

Results. We find that keeping the same parameters as in Bitsch et al. (2015b, A&A, 582, A112) leads to no planet growth due to a computation mistake in the pebble flux (2018b). Indeed a large fraction of the heavy elements should be put into pebbles (Zpeb∕Ztot = 0.9) in order to form massive planets using this approach. The resulting mass functions show a huge amount of giants and a lack of Neptune-mass planets, which are abundant according to observations. To overcome this issue we include the computation of the internal structure for the planetary atmosphere in our model. This leads to the formation of Neptune-mass planets but no observable giants. Furthermore, reducing the opacity of the planetary envelope more closely matches observations.

Conclusions. We conclude that modelling the internal structure for the planetary atmosphere is necessary to reproduce observations.
Discovery of large scale shock fronts correlated with the radio halo and radio relic in the A2163 galaxy cluster
Authors: Thölken Sophia , Reiprich Thomas H. , Sommer Martin W. , Ota Naomi
Published: September 2018

Context. Galaxy clusters form at the intersections of the filamentary large scale structure in merging events and by the accretion of matter along these filaments. Imprints of these formation processes should be visible in the intracluster medium and can arise in shock fronts, which are detectable via discontinuities in, for example, the gas temperature and density profiles. However, relatively few observational examples of prominent shocks have been detected in X-rays so far.

Aims. In this study, we investigate the X-ray properties of the intracluster gas and the radio morphology of the extraordinary cluster A2163. This cluster shows an irregular morphology in various wavelengths and has one of the most luminous and extended radio halos known. Additionally, it is one of the hottest clusters known. We aim to measure the temperature and density profiles in two azimuthal directions to search for the presence of shock fronts.

Methods. We performed a spectral analysis of data from two Suzaku observations, one in the north-east (NE) and one in the southwest (SW) direction of A2163, and used archival XMM-Newton data to remove point sources in the field of view. We deprojected the temperature and density profiles and accounted for the Suzaku point spread function. From the detected discontinuities in the density and temperature profiles, we estimated the Mach numbers and velocities of the shock fronts. To compare our findings in the X-ray regime with the radio emission, we obtained radio images of the cluster from an archival Very Large Array (VLA) observation at 20 cm.

Results. We identify three shock fronts in A2163 in our spectral X-ray study. A clear shock front lies in the NE direction at a distance of 1.4 Mpc from the center, with a Mach number of M = 1.7+0.3−0.2, estimated from the temperature discontinuity. This shock coincides with the position of a known radio relic. We identify two additional shocks in the SW direction, one with M = 1.5+0.5−0.3 at a distance of 0.7 Mpc, which is likely related to a cool core remnant, and a strong shock with M = 3.2+0.6−0.7 at a distance of 1.3 Mpc, which also closely matches the radio contours. The complex structure of A2163 as well as the different Mach numbers and shock velocities suggest a merging scenario with two unequal merging constituents, where two shock fronts emerged at an early stage of the merger and traveled outwards while an additional shock front developed in front of the merging cluster cores.