bluuebunny/crossref_metadata_2025 huggingface dataset:
Coherent diffractive imaging of microtubules using an X-ray laser
Authors: Brändén Gisela , Hammarin Greger , Harimoorthy Rajiv , Johansson Alexander , Arnlund David , Malmerberg Erik , Barty Anton , Tångefjord Stefan , Berntsen Peter , DePonte Daniel P. , Seuring Carolin , White Thomas A. , Stellato Francesco , Bean Richard , Beyerlein Kenneth R. , Chavas Leonard M. G. , Fleckenstein Holger , Gati Cornelius , Ghoshdastider Umesh , Gumprecht Lars , Oberthür Dominik , Popp David , Seibert Marvin , Tilp Thomas , Messerschmidt Marc , Williams Garth J. , Loh N. Duane , Chapman Henry N. , Zwart Peter , Liang Mengning , Boutet Sébastien , Robinson Robert C. , Neutze Richard
Published: June 2019

X-ray free electron lasers (XFELs) create new possibilities for structural studies of biological objects that extend beyond what is possible with synchrotron radiation. Serial femtosecond crystallography has allowed high-resolution structures to be determined from micro-meter sized crystals, whereas single particle coherent X-ray imaging requires development to extend the resolution beyond a few tens of nanometers. Here we describe an intermediate approach: the XFEL imaging of biological assemblies with helical symmetry. We collected X-ray scattering images from samples of microtubules injected across an XFEL beam using a liquid microjet, sorted these images into class averages, merged these data into a diffraction pattern extending to 2 nm resolution, and reconstructed these data into a projection image of the microtubule. Details such as the 4 nm tubulin monomer became visible in this reconstruction. These results illustrate the potential of single-molecule X-ray imaging of biological assembles with helical symmetry at room temperature.
Nickel@Siloxene catalytic nanosheets for high-performance CO2 methanation
Authors: Yan Xiaoliang , Sun Wei , Fan Liming , Duchesne Paul N. , Wang Wu , Kübel Christian , Wang Di , Kumar Sai Govind Hari , Li Young Feng , Tavasoli Alexandra , Wood Thomas E. , Hung Darius L. H. , Wan Lili , Wang Lu , Song Rui , Guo Jiuli , Gourevich Ilya , Ali Feysal M. , Lu Jingjun , Li Ruifeng , Hatton Benjamin D. , Ozin Geoffrey A.
Published: June 2019

Two-dimensional (2D) materials are of considerable interest for catalyzing the heterogeneous conversion of CO2 to synthetic fuels. In this regard, 2D siloxene nanosheets, have escaped thorough exploration, despite being composed of earth-abundant elements. Herein we demonstrate the remarkable catalytic activity, selectivity, and stability of a nickel@siloxene nanocomposite; it is found that this promising catalytic performance is highly sensitive to the location of the nickel component, being on either the interior or the exterior of adjacent siloxene nanosheets. Control over the location of nickel is achieved by employing the terminal groups of siloxene and varying the solvent used during its nucleation and growth, which ultimately determines the distinct reaction intermediates and pathways for the catalytic CO2 methanation. Significantly, a CO2 methanation rate of 100 mmol gNi−1 h−1 is achieved with over 90% selectivity when nickel resides specifically between the sheets of siloxene.
Triple nitrogen-vacancy centre fabrication by C5N4Hn ion implantation
Authors: Haruyama Moriyoshi , Onoda Shinobu , Higuchi Taisei , Kada Wataru , Chiba Atsuya , Hirano Yoshimi , Teraji Tokuyuki , Igarashi Ryuji , Kawai Sora , Kawarada Hiroshi , Ishii Yu , Fukuda Ryosuke , Tanii Takashi , Isoya Junichi , Ohshima Takeshi , Hanaizumi Osamu
Published: June 2019

Quantum information processing requires quantum registers based on coherently interacting quantum bits. The dipolar couplings between nitrogen vacancy (NV) centres with nanometre separation makes them a potential platform for room-temperature quantum registers. The fabrication of quantum registers that consist of NV centre arrays has not advanced beyond NV pairs for several years. Further scaling up of coupled NV centres by using nitrogen implantation through nanoholes has been hampered because the shortening of the separation distance is limited by the nanohole size and ion straggling. Here, we demonstrate the implantation of C5N4Hn from an adenine ion source to achieve further scaling. Because the C5N4Hn ion may be regarded as an ideal point source, the separation distance is solely determined by straggling. We successfully demonstrate the fabrication of strongly coupled triple NV centres. Our method may be extended to fabricate small quantum registers that can perform quantum information processing at room temperature.
The prion-like domain of Drosophila Imp promotes axonal transport of RNP granules in vivo
Authors: Vijayakumar Jeshlee , Perrois Charlène , Heim Marjorie , Bousset Luc , Alberti Simon , Besse Florence
Published: June 2019

Prion-like domains (PLDs), defined by their low sequence complexity and intrinsic disorder, are present in hundreds of human proteins. Although gain-of-function mutations in the PLDs of neuronal RNA-binding proteins have been linked to neurodegenerative disease progression, the physiological role of PLDs and their range of molecular functions are still largely unknown. Here, we show that the PLD of Drosophila Imp, a conserved component of neuronal ribonucleoprotein (RNP) granules, is essential for the developmentally-controlled localization of Imp RNP granules to axons and regulates in vivo axonal remodeling. Furthermore, we demonstrate that Imp PLD restricts, rather than promotes, granule assembly, revealing a novel modulatory function for PLDs in RNP granule homeostasis. Swapping the position of Imp PLD compromises RNP granule dynamic assembly but not transport, suggesting that these two functions are uncoupled. Together, our study uncovers a physiological function for PLDs in the spatio-temporal control of neuronal RNP assemblies.
Environmental pH and peptide signaling control virulence of Streptococcus pyogenes via a quorum-sensing pathway
Authors: Do Hackwon , Makthal Nishanth , VanderWal Arica R. , Saavedra Matthew Ojeda , Olsen Randall J. , Musser James M. , Kumaraswami Muthiah
Published: June 2019

Bacteria control gene expression in concert with their population density by a process called quorum sensing, which is modulated by bacterial chemical signals and environmental factors. In the human pathogen Streptococcus pyogenes, production of secreted virulence factor SpeB is controlled by a quorum-sensing pathway and environmental pH. The quorum-sensing pathway consists of a secreted leaderless peptide signal (SIP), and its cognate receptor RopB. Here, we report that the SIP quorum-sensing pathway has a pH-sensing mechanism operative through a pH-sensitive histidine switch located at the base of the SIP-binding pocket of RopB. Environmental acidification induces protonation of His144 and reorganization of hydrogen bonding networks in RopB, which facilitates SIP recognition. The convergence of two disparate signals in the SIP signaling pathway results in induction of SpeB production and increased bacterial virulence. Our findings provide a model for investigating analogous crosstalk in other microorganisms.
Emergence of plasmid stability under non-selective conditions maintains antibiotic resistance
Authors: Wein Tanita , Hülter Nils F. , Mizrahi Itzhak , Dagan Tal
Published: June 2019

Plasmid acquisition is an important mechanism of rapid adaptation and niche expansion in prokaryotes. Positive selection for plasmid-coded functions is a major driver of plasmid evolution, while plasmids that do not confer a selective advantage are considered costly and expected to go extinct. Yet, plasmids are ubiquitous in nature, and their persistence remains an evolutionary paradox. Here, we demonstrate that non-mobile plasmids persist over evolutionary timescales without selection for the plasmid function. Evolving a minimal plasmid encoding for antibiotics resistance in Escherichia coli, we discover that plasmid stability emerges in the absence of antibiotics and that plasmid loss is determined by transcription-replication conflicts. We further find that environmental conditions modulate these conflicts and plasmid persistence. Silencing the transcription of the resistance gene results in stable plasmids that become fixed in the population. Evolution of plasmid stability under non-selective conditions provides an evolutionary explanation for the ubiquity of plasmids in nature.
Active catalyst construction for CO2 recycling via catalytic synthesis of N-doped carbon on supported Cu
Authors: Wu Yajuan , Wang Tao , Wang Hongli , Wang Xinzhi , Dai Xingchao , Shi Feng
Published: June 2019

Bridging homogeneous and heterogeneous catalysis is a long-term pursuit in the field of catalysis. Herein, we report our results in integration of nano- and molecular catalysis via catalytic synthesis of nitrogen doped carbon layers on AlOx supported nano-Cu which can finely tune the catalytic performance of the supported copper catalyst. This synthetic catalytic material, which can be generated in situ by the reaction of CuAlOx and 1,10-Phen in the presence of hydrogen, could be used for controllable synthesis of N,N-dimethylformamide (DMF) from dimethylamine and CO2/H2via blocking reaction pathways of further catalytic hydrogenation of DMF to N(CH3)3. Detailed characterizations and DFT calculations reveal that the presence of N-doped layered carbon on the surface of the nano-Cu particles results in higher activation energy barriers during the conversion of DMF to N(CH3)3. Our primary results could promote merging of homogeneous catalysis and heterogeneous catalysis and CO2recycling.
Spectral phase control of interfering chirped pulses for high-energy narrowband terahertz generation
Authors: Jolly Spencer W. , Matlis Nicholas H. , Ahr Frederike , Leroux Vincent , Eichner Timo , Calendron Anne-Laure , Ishizuki Hideki , Taira Takunori , Kärtner Franz X. , Maier Andreas R.
Published: June 2019

Highly-efficient optical generation of narrowband terahertz radiation enables unexplored technologies and sciences from compact electron acceleration to charge manipulation in solids. State-of-the-art conversion efficiencies are currently achieved using difference-frequency generation driven by temporal beating of chirped pulses but remain, however, far lower than desired or predicted. Here we show that high-order spectral phase fundamentally limits the efficiency of narrowband difference-frequency generation using chirped-pulse beating and resolve this limitation by introducing a novel technique based on tuning the relative spectral phase of the pulses. For optical terahertz generation, we demonstrate a 13-fold enhancement in conversion efficiency for 1%-bandwidth, 0.361 THz pulses, yielding a record energy of 0.6 mJ and exceeding previous optically-generated energies by over an order of magnitude. Our results prove the feasibility of millijoule-scale applications like terahertz-based electron accelerators and light sources and solve the long-standing problem of temporal irregularities in the pulse trains generated by interfering chirped pulses.
Long-term effect of feeding snacks at age 6 years on body mass index at ages 12 and 22 years
Authors: Sata Mizuki , Yamagishi Kazumasa , Sairenchi Toshimi , Ikeda Ai , Irie Fujiko , Watanabe Hiroshi , Iso Hiroyasu , Ota Hitoshi
Published: June 2019

We investigated the effect of snacking habits in childhood on changes in body mass index (BMI) and high BMI in adolescence and adulthood. In total, 2141 Japanese children from the Ibaraki Children’s Cohort Study were evaluated at age 6 years (baseline), then at ages 12 and 22 years. We examined associations between snacking (scheduled times, when children wanted, and freely) at age 6 years and changes in BMI over time and the proportion of high BMI at ages 12 and 22 years, using time-dependent mixed-effects and logistic regression models. Compared with children who snacked at scheduled times, those provided snacks when they wanted experienced larger increases in BMI over time between ages 6 and 22 years (multivariable time-dependent effect: 0.03 kg/m2 for boys, p = 0.047; 0.04 kg/m2 for girls, p = 0.019). No differences were observed in children who snacked freely. A higher proportion of high BMI was found in boys who were provided snacks when they wanted compared with those who snacked at scheduled times. The multivariable odds ratio (95% confidence interval) was 1.52 (1.04–2.23) at age 12 years and 2.23 (1.12–4.45) at age 22 years. No differences were observed for girls at either age. Children who were provided snacks when they wanted showed larger increases in BMI over time compared with those who snacked at scheduled times. Boys who were provided snacks when they wanted showed the higher proportion of high BMI at follow-up.
Lower Incidence Rate of Type 1 Diabetes after Receipt of the Rotavirus Vaccine in the United States, 2001–2017
Authors: Rogers Mary A. M. , Basu Tanima , Kim Catherine
Published: June 2019

We evaluated whether rotavirus vaccination is associated with the incidence of type 1 diabetes among children. We designed a cohort study of 1,474,535 infants in the United States from 2001–2017, using data from a nationwide health insurer. There was a 33% reduction in the risk of type 1 diabetes with completion of the rotavirus vaccine series compared to the unvaccinated (95% CI: 17%, 46%). Completion of the pentavalent vaccine series was associated with 37% lower risk of type 1 diabetes (95% CI: 22%, 50%). Partial vaccination (incompletion of the series) was not associated with the incidence of type 1 diabetes. There was a 31% reduction in hospitalizations in the 60-day period after vaccination (95% CI: 27%, 35%) compared to unvaccinated children. Overall, there was a 3.4% decrease in incidence annually in children ages 0–4 in the United States from 2006–2017 which coincides with the vaccine introduction in 2006. We conclude that rotavirus vaccination is associated with a reduced incidence of type 1 diabetes. Rotavirus vaccination may be the first practical measure that could play a role in the prevention of this disease.
Author Correction: Quinoxaline protects zebrafish lateral line hair cells from cisplatin and aminoglycosides damage
Authors: Rocha-Sanchez Sonia M. , Fuson Olivia , Tarang Shikha , Goodman Linda , Pyakurel Umesh , Liu Huizhan , He David Z. , Zallocchi Marisa
Published: June 2019

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
Rif1 promotes association of G-quadruplex (G4) by its specific G4 binding and oligomerization activities
Authors: Masai Hisao , Fukatsu Rino , Kakusho Naoko , Kanoh Yutaka , Moriyama Kenji , Ma Yue , Iida Keisuke , Nagasawa Kazuo
Published: June 2019

Rif1 is a conserved protein regulating replication timing and binds preferentially to the vicinity of late-firing/dormant origins in fission yeast. The Rif1 binding sites on the fission yeast genome have an intrinsic potential to generate G-quadruplex (G4) structures to which purified Rif1 preferentially binds. We previously proposed that Rif1 generates chromatin architecture that may determine replication timing by facilitating the chromatin loop formation. Here, we conducted detailed biochemical analyses on Rif1 and its G4 binding. Rif1 prefers sequences containing long stretches of guanines and binds preferentially to the multimeric G4 of parallel or hybrid/mix topology. Rif1 forms oligomers and binds simultaneously to multiple G4. We present a model on how Rif1 may facilitate the formation of chromatin architecture through its G4 binding and oligomerization properties.
Near-infrared spectroscopy as a tool for in vivo analysis of human muscles
Authors: Currà Antonio , Gasbarrone Riccardo , Cardillo Alessandra , Trompetto Carlo , Fattapposta Francesco , Pierelli Francesco , Missori Paolo , Bonifazi Giuseppe , Serranti Silvia
Published: June 2019

Recent advances in materials and fabrication techniques provided portable, performant, sensing optical spectrometers readily operated by user-friendly cabled or wireless systems. Such systems allow rapid, non-invasive, and not destructive quantitative analysis of human tissues. This proof-of-principle investigation tested whether infrared spectroscopy techniques, currently utilized in a variety of areas, could be applied in living humans to categorize muscles. Using an ASD FieldSpec® 4 Standard-Res Spectroradiometer with a spectral sampling capability of 1.4 nm at 350–1000 nm and 1.1 nm at 1001–2500 nm, we acquired reflectance spectra in visible short-wave infra-red regions (350–2500 nm) from the upper limb muscles (flexors and extensors) of 20 healthy subjects (age 25–89 years, 9 women). Spectra off-line analysis included preliminary preprocessing, Principal Component Analysis, and Partial Least-Squares Discriminant Analysis. Near-infrared (NIR) spectroscopy proved valuable for noninvasive assessment of tissue optical properties in vivo. In addition to the non-invasive detection of tissue oxygenation, NIR spectroscopy provided the spectral signatures (ie, “fingerprints”) of upper limb flexors and extensors, which represent specific, accurate, and reproducible measures of the overall biological status of these muscles. Thus, non-invasive NIR spectroscopy enables more thorough evaluation of the muscular system and optimal monitoring of the effectiveness of therapeutic or rehabilitative interventions.
Human Sialic acid O-acetyl esterase (SIAE) – mediated changes in sensitivity to etoposide in a medulloblastoma cell line
Authors: Mather Rebecca L. , Loveson Katie F. , Fillmore Helen L.
Published: June 2019

Medulloblastoma (MB), the most common malignant paediatric brain tumour occurs in the cerebellum. Advances in molecular genomics have led to the identification of defined subgroups which are associated with distinct clinical prognoses. Despite this classification, standard therapies for all subgroups often leave children with life-long neurological deficits. New therapeutic approaches are therefore urgently needed to reduce current treatment toxicity and increase survival for patients. GD3 is a well-studied ganglioside which is known to have roles in the development of the cerebellum. Post-partum GD3 is not highly expressed in the brain. In some cancers however GD3 is highly expressed. In MB cells GD3 is largely acetylated to GD3A. GD3 is pro-apoptotic but GD3A can protect cells from apoptosis. Presence of these gangliosides has previously been shown to correlate with resistance to chemotherapy. Here we show that the GD3 acetylation pathway is dysregulated in MB and as a proof-of-principle we show that increased GD3 expression sensitises an MB cell line to etoposide.
Sex-specific maternofetal innate immune responses triggered by group B Streptococci
Authors: Allard Marie-Julie , Giraud Antoine , Segura Mariela , Sebire Guillaume
Published: June 2019

Group B Streptococcus (GBS) is one of the most common bacteria isolated in human chorioamnionitis, which is a major risk factor for premature birth and brain injuries. Males are at greater risk than females for developing lifelong neurobehavioural disorders, although the origins of this sex bias remain poorly understood. We previously showed that end-gestational inflammation triggered by GBS led to early neurodevelopmental impairments mainly in the male rat progeny. Identifying key inflammatory players involved in maternofetal immune activation by specific pathogens is critical to develop appropriate novel therapeutic interventions. We aimed to map out the GBS-induced profile of innate immune biomarkers in the maternal-placental-fetal axis, and to compare this immune profile between male and female tissues. We describe here that the GBS-induced immune signalling involved significantly higher levels of interleukin (IL)-1β, cytokine-induced neutrophil chemoattractant-1 (CINC-1/CXCL1) and polymorphonuclear cells (PMNs) infiltration in male compared to female maternofetal tissues. Although male – but not female – fetuses presented increased levels of IL-1β, fetuses from both sexes in-utero exposed to GBS had increased levels of TNF-α in their circulation. Levels of IL-1β detected in fetal sera correlated positively with the levels found in maternal circulation. Here, we report for the first time that the maternofetal innate immune signalling induced by GBS presents a sexually dichotomous profile, with more prominent inflammation in males than females. These sex-specific placental and fetal pro-inflammatory responses are in keeping with the higher susceptibility of the male population for preterm birth, brain injuries and neurodevelopmental disorders such as cerebral palsy and autism spectrum disorders.
How Stereotypes Affect Pain
Authors: Schwarz Katharina A. , Sprenger Christian , Hidalgo Pablo , Pfister Roland , Diekhof Esther K. , Büchel Christian
Published: June 2019

Stereotypes are abundant in everyday life – and whereas their influence on cognitive and motor performance is well documented, a causal role in pain processing is still elusive. Nevertheless, previous studies have implicated gender-related stereotype effects in pain perception as potential mediators partly accounting for sex effects on pain. An influence of stereotypes on pain seems indeed likely as pain measures have proven especially susceptible to expectancy effects such as placebo effects. However, so far empirical approaches to stereotype effects on pain are correlational rather than experimental. In this study, we aimed at documenting gender-related stereotypes on pain perception and processing by actively manipulating the participants’ awareness of common stereotypical expectations. We discovered that gender-related stereotypes can significantly modulate pain perception which was mirrored by activity levels in pain-associated brain areas.
Enhancing thermoelectric performance by Fermi level tuning and thermal conductivity degradation in (Ge1−xBix)Te crystals
Authors: Wei Pai-Chun , Cai Cheng-Xun , Hsing Cheng-Rong , Wei Ching-Ming , Yu Shih-Hsun , Wu Hsin-Jay , Chen Cheng-Lung , Wei Da-Hua , Nguyen Duc-Long , Chou Mitch M. C. , Chen Yang-Yuan
Published: June 2019

In this work, a high thermoelectric figure of merit, zT of 1.9 at 740 K is achieved in Ge1−xBixTe crystals through the concurrent of Seebeck coefficient enhancement and thermal conductivity reduction with Bi dopants. The substitution of Bi for Ge not only compensates the superfluous hole carriers in pristine GeTe but also shifts the Fermi level (EF) to an eligible region. Experimentally, with moderate 6–10% Bi dopants, the carrier concentration is drastically decreased from 8.7 × 1020 cm−3 to 3–5 × 1020 cm−3 and the Seebeck coefficient is boosted three times to 75 μVK−1. In the meantime, based on the density functional theory (DFT) calculation, the Fermi level EF starts to intersect with the pudding mold band at L point, where the band effective mass is enhanced. The enhanced Seebeck coefficient effectively compensates the decrease of electrical conductivity and thus successfully maintain the power factor as large as or even superior than that of the pristine GeTe. In addition, the Bi doping significantly reduces both thermal conductivities of carriers and lattices to an extremely low limit of 1.57 W m−1K−1 at 740 K with 10% Bi dopants, which is an about 63% reduction as compared with that of pristine GeTe. The elevated figure of merit observed in Ge1−xBixTe specimens is therefore realized by synergistically optimizing the power factor and downgrading the thermal conductivity of alloying effect and lattice anharmonicity caused by Bi doping.
Binding and Flip as Initial Steps for BP-100 Antimicrobial Actions
Authors: Park Peter , Franco Leandro R. , Chaimovich Hernan , Coutinho Kaline , Cuccovia Iolanda M. , Lima Filipe S.
Published: June 2019

BP100 is a short antimicrobial peptide and can also act as a molecule-carrier into cells. Like with other antimicrobial peptides, the precise mechanism of membrane disruption is not fully understood. Here we use computer simulations to understand, at a molecular level, the initial interaction between BP100 and zwitterionic/negatively charged model membranes. In agreement with experimental results, our simulations showed BP100 folded into an alpha helix when in contact with negatively charged membranes. BP100 binding induced the aggregation of negatively charged lipids on mixed membranes composed of zwitterionic and anionic lipids. The peptide in alpha-helix conformation initially interacts with the membrane via electrostatic interactions between the negatively charged lipids and the positively charged residues of the peptide. At that point the peptide flips, burying the hydrophobic residues into the bilayer highlighting the importance of the hydrophobic effect contribution to the initial interaction of cationic antimicrobial peptides with membranes.
A high temporal resolution numerical algorithm for shock wave velocity diagnosis
Authors: Wu Yuji , Wang Feng , Wang Qiuping , Li Yulong , Jiang Shaoen
Published: June 2019

We propose a high temporal resolution numerical algorithm for shock wave velocity diagnosis. By analysing variations in the optical path and phasor of a light field, we determine a high temporal resolution shock wave velocity equation for a velocity interferometer system for any reflector (VISAR). The equation can be transformed into matrix form for numerical solution. To solve noise problems, a ‘filtering velocity spectrum’ method is proposed. Analysis of a VISAR data example shows that the resolution precision of shock wave velocity obtained from the numerical algorithm is the same as the temporal resolution of a streak camera. Moreover, it can observe the shock wave in greater detail. This algorithm can be used to observe detailed images and determine the mechanism and evolution of extreme shock waves, as well as provide data for research into hydrodynamic behaviour in inertial confinement fusion.
Grain Boundary Interfaces Controlled by Reduced Graphene Oxide in Nonstoichiometric SrTiO3-δ Thermoelectrics
Authors: Rahman Jamil Ur , Du Nguyen Van , Nam Woo Hyun , Shin Weon Ho , Lee Kyu Hyoung , Seo Won-Seon , Kim Myong Ho , Lee Soonil
Published: June 2019

Point defect or doping in Strontium titanium oxide (STO) largely determines the thermoelectric (TE) properties. So far, insufficient knowledge exists on the impact of double Schottky barrier on the TE performance. Herein, we report a drastic effect of double Schottky barrier on the TE performance in undoped STO. It demonstrates that incorporation of Reduced Graphene Oxide (RGO) into undoped STO weakens the double Schottky barrier and thereby results in a simultaneous increase in both carrier concentration and mobility of undoped STO. The enhanced mobility exhibits single crystal-like behavior. This increase in the carrier concentration and mobility boosts the electrical conductivity and power factor of undoped STO, which is attributed to the reduction of the double Schottky barrier height and/or the band alignment of STO and RGO that allow the charge transfer through the interface at grain boundaries. Furthermore, this STO/RGO interface also enhances the phonon scattering, which results in low thermal conductivity. This strategy significantly increases the ratio of σ/κ, resulting in an enhancement in ZT as compared with pure undoped STO. This study opens a new window to optimize the TE properties of many candidate materials.
Enhancement of hydrophobicity and UV aging resistance of Poly (p-phenylene benzobisoxazole) fibers modified by fluorosilane and UV absorber
Authors: Li Zhihua , Yang Yu , Li Hui , Liu Lanlan , Zou Dehua
Published: June 2019

Poly (p-phenylene benzobisoxazole) (PBO) fibers were functionalized by 3-Glycidoxypropyltrimethoxysilane (KH-560) and then coated with 1 H, 1 H, 2 H, 2H-Perfluorodecyltrimethoxysilane (HFTES) and UV absorber (UV-328) to improve hydrophobicity and UV aging resistance. The chemical compositions of PBO fibers before and after modification were analyzed by XPS and surface morphologies were observed by SEM. The hydrophobicity of PBO fibers was evaluated by the measurement of contact angle for water and the UV aging resistance was evaluated by the tensile strength retention ratio of PBO fibers. The results showed that KH-560 was successfully introduced onto the PBO fiber surface. The contact angle for water was increased by 128% from 51.7° to 127°, suggesting a huge improvement of hydrophobicity. The UV aging resistance of PBO fibers was also greatly improved. After 400 h UV exposure, the tensile strength retention ratio was increased to 53%, which was much higher than that of 21.4% for pristine PBO fibers. And the results of variable coating times demonstrated that the optimal UV aging resistance was obtained by coating three times.
Triazole-appended pyrano[2,3-c]pyrazolone based colorimetric chemosensors for recognition of Fe3+ ions and their molecular logic gate behavior
Authors: Jain Harshita , Deswal Nidhi , Joshi Ankita , Ramachandran C. N. , Kumar Rakesh
Published: June 2019

Two novel triazole-appended pyrano[2,3-c]pyrazolone based colorimetric and reversible chemosensors have been synthesized for recognition of Fe3+ ions for practical applications.
Correction: Enzyme-mediated dual-targeted-assembly realizes a synergistic anticancer effect
Authors: Mang‡ Dingze , Zhang‡ Shijin , Wu Xia , Hu Xunwu , Mochizuki Toshiaki , Li Guanying , Zhang Ye
Published: June 2019

Correction for ‘Enzyme-mediated dual-targeted-assembly realizes a synergistic anticancer effect’ by Dingze Mang et al., Chem. Commun., 2019, 55, 6126–6129.
Stable, one-dimensional suspended and supported monatomic chains of pnictogens: a metal–insulator framework
Authors: Ersan F. , Aktürk E. , Ciraci S.
Published: June 2019

Group-VA elements P, As, Sb, and Bi can construct free-standing, stable zigzag monatomic chain structures, which show unusual properties.
Additive-free cobalt-catalysed hydrogenation of carbonates to methanol and alcohols
Authors: Ferretti Francesco , Scharnagl Florian Korbinian , Dall'Anese Anna , Jackstell Ralf , Dastgir Sarim , Beller Matthias
Published: June 2019

Homogeneously cobalt-catalyzed hydrogenation of cyclic and acyclic carbonates: beneficial effects of 2,2,2-trifluoroethanol and triphos-derivatives.
X-ray tomography shows the varying three-dimensional morphology of gold nanoaggregates in the cellular ultrastructure
Authors: Drescher Daniela , Büchner Tina , Guttmann Peter , Werner Stephan , Schneider Gerd , Kneipp Janina
Published: June 2019

Soft X-ray tomography data were used for volume rendering of both cellular organelles and intracellular gold nanoparticle aggregates. They reveal variation in properties of the nanoaggregates with incubation time, cell type, and particle properties.
Performance and structural features of LaNi0.5Co0.5O3 perovskite oxides for the dry reforming of methane: influence of the preparation method
Authors: Mousavi Maryam , Nakhaei Pour Ali
Published: June 2019

LaNiO3 and LaNi0.5Co0.5O3 as perovskites were synthesized in magnetized and non-magnetized water and the activity of the catalysts was evaluated in the methane dry reforming reaction with CO2.
General microemulsion synthesis of organic–inorganic hybrid hollow mesoporous silica spheres with enlarged pore size
Authors: Sun Yangyi , Zhang Chengyu , Mao Yijing , Pan Dongyu , Qi Dongming , Di Ningyu
Published: June 2019

General microemulsion synthesis of organic–inorganic hybrid hollow mesoporous silica spheres with enlarge pore size with different kinds of pore expanders.
TiO2 nanotrees for the photocatalytic and photoelectrocatalytic phenol degradation
Authors: Xie Juan , Wen Wei , Jin Qi , Xiang Xiao-Bo , Wu Jin-Ming
Published: June 2019

Constructing nanotrees is an effective method to enhance the photoelectrocatalytic efficiency of TiO2 using single-crystalline trunks with an appropriate length.
Advanced on-site glucose sensing platform based on a new architecture of free-standing hollow Cu(OH)2nanotubes decorated with CoNi-LDH nanosheets on graphite screen-printed electrode
Authors: Shahrokhian Saeed , Khaki Sanati Elnaz , Hosseini Hadi
Published: June 2019

Fabrication of new architecture of free-standing hollow Cu(OH)2nanotubes decorated with CoNi-LDH nanosheets on graphite screen-printed electrode for advanced on-site glucose sensing platform.
Insight into the antitumor activity of carbosilane Cu(ii)–metallodendrimers through their interaction with biological membrane models
Authors: Sanz del Olmo Natalia , Carloni Riccardo , Bajo Ana M. , Ortega Paula , Fattori Alberto , Gómez Rafael , Ottaviani Maria Francesca , García-Gallego Sandra , Cangiotti Michela , de la Mata F. Javier
Published: June 2019

We present a new family of water-soluble copper(ii) carbosilane metallodendrimers. The combined experimental and theoretical analysis reveals that they display different interactions with model membranes, which also dictate their antitumor behavior.
The role of olefin geometry in the activity of hydrocarbon stapled peptides targeting eukaryotic translation initiation factor 4E (eIF4E)
Authors: Song James M. , Gallagher Erin E. , Menon Arya , Mishra Lauren D. , Garner Amanda L.
Published: June 2019

Ring-closing metathesis of monosubstituted alkenyl amino acids leads to stapled peptides with differing olefin geometry and biological activity.
The first radiosynthesis of 2-amino-5-[18F]fluoropyridines via a “minimalist” radiofluorination/palladium-catalyzed amination sequence from anisyl(2-bromopyridinyl)iodonium triflate
Authors: Pauton Mathilde , Gillet Raphaël , Aubert Catherine , Bluet Guillaume , Gruss-Leleu Florence , Roy Sébastien , Perrio Cécile
Published: June 2019

Radiofluorination of anisyl(2-bromopyridinyl)iodonium triflate under “minimalist” conditions: an entry to 2-amino-5-[18F]fluoropyridines via Buchwald–Hartwig amination.
A tetrahedral molecular cage with a responsive vertex
Authors: Pattillo Christopher C. , Moore Jeffrey S.
Published: June 2019

The first system to combine the orthogonality of alkyne metathesis and dynamic imine exchange is reported for the preparation of a molecular cage with a reversibly removable vertex.
Quasi-3D morphology and modulation of focal adhesions of human adult stem cells through combinatorial concave elastomeric surfaces with varied stiffness
Authors: Portone A. , Sciancalepore A. G. , Melle G. , Netti G. S. , Greco G. , Persano L. , Gesualdo L. , Pisignano D.
Published: June 2019

Concave surface topography led stem cells in a quasi-three dimensional configuration where stiffness steers mechanosensing highlighted by focal adhesion properties.
Biocompatible and multifunctional gold nanorods for effective photothermal therapy of oral squamous cell carcinoma
Authors: Liao Yu-Te , Liu Chia-Hung , Chin Yin , Chen Sin-Yuan , Liu Shing Hwa , Hsu Yih-Chih , Wu Kevin C.-W.
Published: June 2019

Functionalized gold nanorods were successfully synthesized for the effective photothermal therapy of oral cancer.
From single bacterial cell imaging towards in vivo single-molecule biochemistry studies
Authors: Endesfelder Ulrike
Published: June 2019

Bacteria as single-cell organisms are important model systems to study cellular mechanisms and functions. In recent years and with the help of advanced fluorescence microscopy techniques, immense progress has been made in characterizing and quantifying the behavior of single bacterial cells on the basis of molecular interactions and assemblies in the complex environment of live cultures. Importantly, single-molecule imaging enables the in vivo determination of the stoichiometry and molecular architecture of subcellular structures, yielding detailed, quantitative, spatiotemporally resolved molecular maps and unraveling dynamic heterogeneities and subpopulations on the subcellular level. Nevertheless, open challenges remain. Here, we review the past and current status of the field, discuss example applications and give insights into future trends.
Output feedback control of large‐scale non‐linear time‐delay systems with unknown measurement sensitivities
Authors: Li Hanfeng , Zhang Xianfu , Hou Ting
Published: June 2019

This study is concerned with the output feedback stabilisation problem for a class of large‐scale non‐linear time‐delay systems with unknown measurement sensitivities. The non‐linear terms are assumed to be bounded by states or delayed states multiplied by outputs polynomial functions. The state observers are given by the dynamic gain control design technique. By constructing an appropriate Lyapunov–Krasovskii functional, the global asymptotic stability of the closed‐loop control system is analysed. A numerical example is given to illustrate the effectiveness of the proposed control scheme.
Optimal output anti‐synchronisation of cooperative‐competitive multi‐agent systems via distributed observer
Authors: Wu Yanzhi , Zhao Yiyi , Hu Jiangping
Published: June 2019

This study considers an optimal output anti‐synchronisation problem for linear multi‐agent systems with non‐identical dynamics and antagonistic interactions. It is assumed that the agents are non‐introspective, i.e. they cannot get their own states or outputs, and can only get a linear combination of relative outputs in the neighbourhood. First, a state transformation is made, which aims at reducing the dimension of the model underlying the output anti‐synchronisation errors by removing redundant modes that have no effect on the output anti‐synchronisation errors. Then, optimal state feedback controllers are proposed for agents to realise the output anti‐synchronisation by constructing discounted performance functions and by solving the discounted algebraic Riccati equation. Moreover, by using an iterative technique, an offline algorithm is provided to solve the linear quadratic tracking problem. In addition, a distributed node‐based adaptive observer is proposed to produce an estimate of the state with only relative output information of neighbouring agents by utilising a high‐gain approach. The convergence of the proposed adaptive observer is analysed with the help of a Lyapunov function method. Finally, numerical simulations are carried out to demonstrate the effectiveness of the proposed approach.
Impulsive observer‐based output control for PMSG‐based Wind Energy Conversion System
Authors: Vinodkumar Arumugam , Prakash Mani , Joo Young Hoon
Published: June 2019

The main intention of this study is to design the fuzzy impulsive observer‐based output controller scheme for hybrid Takagi–Sugeno (T–S) fuzzy permanent magnet synchronous generator (PMSG) model. Initially, the non‐linearities of the PMSG differential model is equivalently transformed into linear sub‐models via T–S fuzzy approach. Then, the theoretical sufficient conditions are derived by utilising the Lyapunov stability theory. Distinct to the existing studies, the overall contributions of the present work is summarised as follows: (i) the paper proposes the impulsive controller, which is a combination of both continuous and discontinuous factors that can handle the uncertainties in a complex T–S fuzzy PMSG model. (ii) The time‐dependent Lyapunov functional (based on parallel distributed compensation method) has introduced for the given model, and then the sufficient conditions are proposed as solvable linear matrix inequalities. The simulation concerning the industrial problem of PMSG model is validated with the proposed theoretical conditions that guarantee the global asymptotic stability performance of the chaotic model.
Distributed adaptive three‐dimension formation control based on improved RBF neural network for non‐linear multi‐agent time‐delay systems
Authors: Zhang Mingyang , Yu Xinyi , Ding Peixuan , Ou Linlin , Zhang Weidong
Published: June 2019

Based on the improved radial basis function (RBF) neural networks, the distributed three‐dimension formation control scheme in the presence of dynamic uncertainties is studied for non‐linear multi‐agent systems with time delay. A virtual leader which tracks the desired signal is followed by all agents adaptively. Linear reduced‐order observers are designed on the basis of absolute and local state errors of each agent. The local state error and absolute state error are generated between neighbouring agents and each individual agent in formation, respectively. The time delay for each agent in the formation can be offset by designing a Lyapunov function, which can simplify the controller design. To deal with non‐linear dynamic uncertainties and unavoidable disturbance, improved RBF neural networks are employed. In comparison with traditional RBF neural networks, improved RBF neural networks can provide better convergence performance. Subsequently, the formation controller is designed and the stability of the systems is validated by using a new Lyapunov function. Numerical simulation is conducted to demonstrate the effectiveness of the proposed method for non‐linear multi‐agent time‐delay systems.
Inductive decoupling‐based multi‐channel LED driver without electrolytic capacitors
Authors: Ye Cikai , Das Pritam , Sahoo Sanjib Kumar
Published: June 2019

Light‐emitting diode (LED) drivers in outdoor street lighting applications suffer from short‐lifetime because of the prolonged exposure to harsh environmental conditions such as high operating temperature, high humidity etc. A long‐lifetime multi‐channel LED driver consisting of front‐end AC–DC boost power factor correction (PFC) converter followed by a DC–DC power conversion stage with dimming capability for LED‐based street light is proposed in this study. This LED driver uses an inductor‐based auxiliary decoupling circuit at the output of the AC–DC converter for mitigating the double‐line‐frequency power ripple present in the DC bus. The inductive ripple power storage circuit has a longer lifetime than a conventional capacitive storage circuit which is usually implemented by electrolytic capacitors. A digital control method is proposed to realise the decoupling control along with PFC control by a single non‐digital signal processor micro‐controller ST STM32F103RBT6. The proposed LED driver for street lighting is analysed and validated on a 150 W test setup. A comparison of active decoupling AC–DC converters for eliminating secondary‐harmonic power ripple is displayed.
IoT‐based approach to condition monitoring of the wave power generation system
Authors: Qian Peng , Feng Bo , Zhang Dahai , Tian Xiange , Si Yulin
Published: June 2019

Accurate and reliable fault detecting plays a key role in application of grid‐connected wave power generation systems. This study presents a novel IoT‐based approach to condition monitoring of the wave power generation system, which has faster operating rate and lower hardware requirement. The compressed sensing (CS) method is adopted to compress the data, which aims to reduce the data uploaded to cloud platform; and then, the extreme learning machine (ELM) algorithm is used to achieve the condition monitoring of wave power generation system in cloud platform. In order to validate the effectiveness of the proposed method, the IoT‐based wave power generation condition monitoring system test platform is established. The experiment results illustrate the high efficiency and reliability of proposed method. The proposed method has a potential of practical applications.
Comparison of SBR and MLFMM techniques for the computation of RCS of a fighter aircraft
Authors: Bilal Ahmad , Hamza Syed Muhammad , Taj Ziauddin , Salamat Shuaib
Published: June 2019

In this work, an extensive correlation between two commonly used radar cross‐section (RCS) computation techniques, i.e. shooting and bouncing rays (SBR) and multilevel fast multipole method (MLFMM), is performed. Numerical results are compared with the measured data, obtained from an anechoic chamber, for a 1:8 scaled down model of a fighter aircraft. It is ascertained that the SBR method, notwithstanding its numerical simplicity, can provide qualitatively similar and reasonably accurate RCS results for an object of varying complexity.
Pebble-driven planet formation for TRAPPIST-1 and other compact systems
Authors: Schoonenberg Djoeke , Liu Beibei , Ormel Chris W. , Dorn Caroline
Published: June 2019

Recently, seven Earth-sized planets were discovered around the M-dwarf star TRAPPIST-1. Thanks to transit-timing variations, the masses and therefore the bulk densities of the planets have been constrained, suggesting that all TRAPPIST-1 planets are consistent with water mass fractions on the order of 10%. These water fractions, as well as the similar planet masses within the system, constitute strong constraints on the origins of the TRAPPIST-1 system. In a previous work, we outlined a pebble-driven formation scenario. In this paper we investigate this formation scenario in more detail. We used a Lagrangian smooth-particle method to model the growth and drift of pebbles and the conversion of pebbles to planetesimals through the streaming instability. We used the N-body code MERCURY to follow the composition of planetesimals as they grow into protoplanets by merging and accreting pebbles. This code is adapted to account for pebble accretion, type-I migration, and gas drag. In this way, we modelled the entire planet formation process (pertaining to planet masses and compositions, not dynamical configuration). We find that planetesimals form in a single, early phase of streaming instability. The initially narrow annulus of planetesimals outside the snowline quickly broadens due to scattering. Our simulation results confirm that this formation pathway indeed leads to similarly-sized planets and is highly efficient in turning pebbles into planets. Our results suggest that the innermost planets in the TRAPPIST-1 system grew mostly by planetesimal accretion at an early time, whereas the outermost planets were initially scattered outwards and grew mostly by pebble accretion. The water content of planets resulting from our simulations is on the order of 10%, and our results predict a “V-shaped” trend in the planet water fraction with orbital distance: from relatively high (innermost planets) to relatively low (intermediate planets) to relatively high (outermost planets).