bluuebunny/crossref_metadata_2025 huggingface dataset:
Multilocus Sequence Typing Reveals both Shared and Unique Genotypes of Cryptococcus neoformans in Jiangxi Province, China
Authors: Chen Yan-Hui , Yu Feng , Bian Ze-Yuan , Hong Jian-Ming , Zhang Nan , Zhong Qiao-Shi , Hang Ya-Ping , Xu Jianping , Hu Long-Hua
Published: January 2018

Cryptococcosis is a globally distributed infectious fungal disease. However, much remains unknown about its molecular epidemiology in many parts of the world. In this study, we analyzed 86 clinical Cryptococcus neoformans isolates from 14 regions in Jiangxi Province in south central China. Each isolate was from a different patient and 35 of the 86 (40.7%) patients were infected with HIV. All strains belonged to serotype A and mating type α (MATα). Genotyping based on DNA sequences at seven nuclear loci revealed eight sequence types (STs) among the 86 isolates, including two novel STs that have not been reported from other parts of the world. ST5 was the dominant genotype and our comparative analyses showed that these genotypes in Jiangxi likely originated by dispersal from other regions within and outside of China and/or mutations from another genotype within Jiangxi. Though none of the isolates was resistant to the five tested antifungal drugs (flucytosine, amphotericin B, fluconazole, itraconazole, and voriconazole), obvious differences in their minimum inhibitory concentrations were observed, even among isolates of the same ST. Our results suggest that continuous monitoring should be conducted to understand the changing dynamics of C. neoformans in this and other regions.
Highly sensitive colorimetric detection of allergies based on an immunoassay using peroxidase-mimicking nanozymes
Authors: Cho Seongyeon , Lee Sang Min , Shin Ho Yun , Kim Min Su , Seo Yiel Hea , Cho Yong Kyun , Lee Jinwoo , Lee Sang Pyo , Kim Moon Il
Published: January 2018

A highly efficient colorimetric allergy detection system is developed based on an immunoassay utilizing the peroxidase-mimicking activity of hierarchically structured platinum nanoparticles.
Zn-Porphyrin propped with hydantoin anchor: synthesis, photophysics and electron injection/recombination dynamics
Authors: Ram Kumar Poomani , Mothi Ebrahim M. , Ramesh Mohan , Kathiravan Arunkumar
Published: January 2018

In this work, Zn-porphyrin with a hydantoin anchor (ZnPHy) was designed and synthesized for dye-sensitized solar cell (DSC) applications.
Facile, non-destructive characterization of 2d photonic crystals using UV-vis-spectroscopy
Authors: Schöps V. , Lenyk B. , Huhn T. , Boneberg J. , Scheer E. , Offenhäusser A. , Mayer D.
Published: January 2018

The quality of particle monolayers and size evolution of their particles during dry etching can be monitored by radiative losses of photonic modes into dielectric substrates.
Ab initio calculations and kinetic modeling of thermal conversion of methyl chloride: implications for gasification of biomass
Authors: Singla Mallika , Rasmussen Morten Lund , Hashemi Hamid , Wu Hao , Glarborg Peter , Pelucchi Matteo , Faravelli Tiziano , Marshall Paul
Published: January 2018

Ab initio theory is used to obtain rate coefficients for key reactions in the CH3Cl subset; kinetic modeling is then used for analysis of practical application.
Effect of Al content on the strength of terminal silanol species in ZSM-5 zeolite catalysts: a quantitative DRIFTS study without the use of molar extinction coefficients
Authors: Bräuer Pierre , Situmorang Olivia , Ng Pey Ling , D’Agostino Carmine
Published: January 2018

DRIFTS is used to quantify the effect of Al content on the strength of silanol sites in ZSM-5 zeolites. The applied protocol does not require the use of molar extinction coefficients.
Catalytic conversion of biomass-derived levulinic acid into alcohols over nanoporous Ru catalyst
Authors: Lv Jinkun , Rong Zeming , Sun Liming , Liu Chengyun , Lu An-Hui , Wang Yue , Qu Jingping
Published: January 2018

1,4-pentanediol or monohydric alcohol were achieved with high selectivity from levulinic acid under relatively mild conditions using nanoporous Ru.
Zirconia catalysed acetic acid ketonisation for pre-treatment of biomass fast pyrolysis vapours
Authors: Jahangiri Hessam , Osatiashtiani Amin , Bennett James A. , Isaacs Mark A. , Gu Sai , Lee Adam F. , Wilson Karen
Published: January 2018

Weak Lewis acid sites (and/or resulting acid–base pairs) on monoclinic ZrO2 are identified as the active species responsible for acetic acid ketonisation to acetone.
Emerging investigator series: methylmercury speciation and dimethylmercury production in sulfidic solutions
Authors: Kanzler Charlotte R. , Lian Peng , Trainer Emma Leverich , Yang Xiaoxuan , Govind Niranjan , Parks Jerry M. , Graham Andrew M.
Published: January 2018

Experimental and computational evidence show that dimethylmercury is produced from decomposition of bis(methylmercury(ii)) sulfide.
An integrated process for the production of 2,5-dihydroxymethylfuran and its polymer from fructose
Authors: Upare Pravin P. , Hwang Young Kyu , Hwang Dong Won
Published: January 2018

Fructose is selectively transformed to poly(2,5-furandimethylene succinate) by integration of dehydration, hydrogenation, and condensation with succinic acid in 1-butanol.
Online isotope analysis of 37Cl/35Cl universally applied for semi-volatile organic compounds using GC-MC-ICPMS
Authors: Renpenning Julian , Horst Axel , Schmidt Matthias , Gehre Matthias
Published: January 2018

This study demonstrates a sensitive compound-specific online method for chlorine isotopes in semi-volatile organic compounds.
Flocculation on a chip: a novel screening approach to determine floc growth rates and select flocculating agents
Authors: P. Radhakrishnan Anand N. , Marques Marco P. C. , Davies Matthew J. , O'Sullivan Brian , Bracewell Daniel G. , Szita Nicolas
Published: January 2018

A novel microfluidic flocculation screening tool to efficiently compare flocculating agents and rapidly find the best flocculating condition usingin situdetection of flocculation growth rates.
Synthesis and properties of wide bandgap polymers based on tetraphenylsilane and their applications as hosts in electrophosphorescent devices
Authors: Li Xiaoxiao , Bai Qing , Li Jinyu , Lu Fang , Sun Xiaoyi , Lu Ping
Published: January 2018

By introducing the electron-withdrawing diphenylphosphine oxide in PFSCPO, its doped OLEDs achieve enhanced current and external quantum efficiencies than the PFSC-hosted device.
Hydrophilic K2Mn4O8 nanoflowers as a sensitive photothermal theragnosis synergistic platform for the ablation of cancer
Authors: Peng Yuxuan , Zhang Fei , Huang Xiaojuan , Li Bo , Guan Guoqiang , Zhang Wenlong , Zou Rujia , Lu Xinwu , Hu Junqing
Published: January 2018

Hydrophilic flower-like K2Mn4O8 is fabricated and works simultaneously as an effective photothermal agent and an ultrasensitive T1-weighted MRI enhancing agent.
Four new quaternary chalcogenides A2Ba7Sn4Q16 (A = Li, Na; Q = S, Se): syntheses, crystal structures determination, nonlinear optical performances investigation
Authors: Abudurusuli Ailijiang , Wu Kui , Pan Shilie
Published: January 2018

Four new quaternary chalcogenides with interesting structures and potential nonlinear optical performances were synthesized for the first time.
Facile synthesis of FeCo alloys encapsulated in nitrogen-doped graphite/carbon nanotube hybrids: efficient bi-functional electrocatalysts for oxygen and hydrogen evolution reactions
Authors: Du Bing , Meng Qing-Ting , Sha Jing-Quan , Li Ji-Sen
Published: January 2018

Novel FeCo alloys encapsulated in nitrogen-doped graphite/carbon nanotube composite based on MOFs was firstly obtained. Impressively, the hybrid demonstrates the outstanding electrocatalytic performance for the oxygen and hydrogen evolution reaction.
A highly selective and sensitive chemosensor forl-tryptophan by employing a Schiff based Cu(ii) complex
Authors: Saini Anoop Kumar , Saraf Mohit , Kumari Pratibha , Mobin Shaikh M.
Published: January 2018

Construction of a new Cu(ii) complex (1) based modified glassy carbon electrode (1-GCE) for highly selective and sensitive detection ofl-tryptophan (l-Trp).
New insights into the protogenic and spectroscopic properties of commercial tannic acid: the role of gallic acid impurities
Authors: Ghigo G. , Berto S. , Minella M. , Vione D. , Alladio E. , Nurchi V. M. , Lachowicz J. , Daniele P. G.
Published: January 2018

Assessment of a protonation model for tannic acid and characterization of the spectral features of its protonated and dissociated species.
Natural products and ring-closing metathesis: synthesis of sterically congested olefins
Authors: Lecourt C. , Dhambri S. , Allievi L. , Sanogo Y. , Zeghbib N. , Ben Othman R. , Lannou M.-I. , Sorin G. , Ardisson J.
Published: January 2018

This review highlights RCM reactions towards the synthesis of sterically congested natural products throughout the recent evolution of catalysts.
A crystalline and 3D periodically ordered mesoporous quaternary semiconductor for photocatalytic hydrogen generation
Authors: Weller Tobias , Deilmann Leonie , Timm Jana , Dörr Tobias S. , Beaucage Peter A. , Cherevan Alexey S. , Wiesner Ulrich B. , Eder Dominik , Marschall Roland
Published: January 2018

The first crystalline and 3D periodically ordered mesoporous quaternary semiconductor for photocatalytic hydrogen production has been prepared.
A thieno[3,4-b]thiophene linker enables a low-bandgap fluorene-cored molecular acceptor for efficient non-fullerene solar cells
Authors: Fan Haijun , Vergote Thomas , Xu Shengjie , Chen Shanshan , Yang Changduk , Zhu Xiaozhang
Published: January 2018

By introducing a thieno[3,4-b]thiophene linker, a low-bandgap fluorene-cored molecular acceptor was achieved, delivering a high PCE of 9.02%.
Controlling nanodomain morphology of epoxy thermosets templated by poly(caprolactone)-block-poly(dimethylsiloxane)-block-poly(caprolactone) ABA triblock copolymer
Authors: Yang Jingyi , Zhou Quan , Shen Kang , Song Ning , Ni Lizhong
Published: January 2018

FTIR spectrum of PDMS and PCL-b-PDMS-b-PCL triblock copolymer..
Hexagonal nanoplates of high-quality γ-gallium oxide: controlled synthesis and good heterogeneous catalytic performance for thiophenes
Authors: Yang Zun , Song Le Xin , Wang Ya Qian , Ruan Mao Mao , Teng Yue , Xia Juan , Yang Jun , Chen Shan Shan , Wang Fang
Published: January 2018

Hexagonal nanoplates of high-quality γ-gallium oxide were successfully synthesized by using a competitive and cooperative interaction model.
Structural insights into the catalytic mechanism of cysteine (hydroxyl) lyase from the hydrogen sulfide-producing oral pathogen, Fusobacterium nucleatum
Authors: Kezuka Yuichiro , Ishida Tetsuo , Yoshida Yasuo , Nonaka Takamasa
Published: January 2018

Hydrogen sulfide (H2S) plays important roles in the pathogenesis of periodontitis. Oral pathogens typically produce H2S from l-cysteine in addition to pyruvate and . However, fn1055 from Fusobacterium nucleatum subsp. nucleatum ATCC 25586 encodes a pyridoxal 5′-phosphate (PLP)-dependent enzyme that catalyzes the production of H2S and l-serine from l-cysteine and H2O, an unusual cysteine (hydroxyl) lyase reaction (β-replacement reaction). To reveal the reaction mechanism, the crystal structure of substrate-free Fn1055 was determined. Based on this structure, a model of the l-cysteine-PLP Schiff base suggested that the thiol group forms hydrogen bonds with Asp232 and Ser74, and the substrate α-carboxylate interacts with Thr73 and Gln147. Asp232 is a unique residue to Fn1055 and its substitution to asparagine (D232N) resulted in almost complete loss of β-replacement activity. The D232N structure obtained in the presence of l-cysteine contained the α-aminoacrylate-PLP Schiff base in the active site, indicating that Asp232 is essential for the addition of water to the α-aminoacrylate to produce the l-serine-PLP Schiff base. Rapid-scan stopped-flow kinetic analyses showed an accumulation of the α-aminoacrylate intermediate during the reaction cycle, suggesting that water addition mediated by Asp232 is the rate-limiting step. In contrast, mutants containing substitutions of other active-site residues (Ser74, Thr73, and Gln147) exhibited reduced β-replacement activity by more than 100-fold. Finally, based on the structural and biochemical analyses, we propose a mechanism of the cysteine (hydroxyl) lyase reaction by Fn1055. The present study leads to elucidation of the H2S-producing mechanism in F. nucleatum.
Structural and functional characterisation of the cytochrome P450 enzyme CYP268A2 fromMycobacterium marinum
Authors: Child Stella A. , Naumann Elise F. , Bruning John B. , Bell Stephen G.
Published: January 2018

Members of the cytochrome P450 monooxygenase family CYP268 are found across a broad range of Mycobacterium species including the pathogens Mycobacterium avium, M. colombiense, M. kansasii, and M. marinum. CYP268A2, from M. marinum, which is the first member of this family to be studied, was purified and characterised. CYP268A2 was found to bind a variety of substrates with high affinity, including branched and straight chain fatty acids (C10–C12), acetate esters, and aromatic compounds. The enzyme was also found to bind phenylimidazole inhibitors but not larger azoles, such as ketoconazole. The monooxygenase activity of CYP268A2 was efficiently reconstituted using heterologous electron transfer partner proteins. CYP268A2 hydroxylated geranyl acetate and trans-pseudoionone at a terminal methyl group to yield (2E,6E)-8-hydroxy-3,7-dimethylocta-2,6-dien-1-yl acetate and (3E,5E,9E)-11-hydroxy-6,10-dimethylundeca-3,5,9-trien-2-one, respectively. The X-ray crystal structure of CYP268A2 was solved to a resolution of 2.0 Å with trans-pseudoionone bound in the active site. The overall structure was similar to that of the related phytanic acid monooxygenase CYP124A1 enzyme from Mycobacterium tuberculosis, which shares 41% sequence identity. The active site is predominantly hydrophobic, but includes the Ser99 and Gln209 residues which form hydrogen bonds with the terminal carbonyl group of the pseudoionone. The structure provided an explanation on why CYP268A2 shows a preference for shorter substrates over the longer chain fatty acids which bind to CYP124A1 and the selective nature of the catalysed monooxygenase activity.
Data‐driven partition control strategy for harmonic distortion and voltage unbalance
Authors: Yu Hao , Jia Qingquan , Sun Haidong , Dong Haiyan
Published: January 2018

Local controls for harmonic distortion and voltage unbalance have become inapplicable due to the increasing penetration and decentralisation of disturbance sources. The complication and expansion of distribution networks cause difficulties in measuring certain system parameters, which reduce the practicability of global optimisation controls. Accordingly, this study introduces a partition control strategy driven by the disturbance data of nodes, which is used to allocate active power filters (APFs) to individually or simultaneously suppress harmonic distortion and voltage unbalance in distribution networks. A multidimensional piecewise linear representation based on local extreme points is proposed to extract the trend features of univariate disturbance time series (UDTS) and multivariate DTS (MDTS). Trend features, disturbance severities, and subsection lengths are used to establish a parameter matrix as the pattern representation of DTS. A feature distance (FD) method is developed to implement pattern matching on UDTS or MDTS to measure the coupling degrees of single or integrated disturbance among nodes. Area division and APF allocation are performed based on the coupling degrees. Case studies on a 14‐bus distribution system are conducted to verify the rationality of the partition control strategy and the accuracy of the FD method.
Fault location algorithm for multi‐terminal mixed lines with shared tower and different voltage levels
Authors: Saber Ahmed
Published: January 2018

This study presents a new fault location algorithm for multiple‐circuit shared tower transmission lines with different voltages utilising synchronised measurements. The formulation of the proposed algorithm is based on overhead transmission lines theory and Taylor series expansion of distributed‐parameter line model. The untransposition of the lines and the mutual coupling between the parallel lines are considered to achieve precise fault location. Kirchhoff's current law and fault location equation are used to identify the faulty section and obtain the location of all normal shunt faults and inter‐circuit faults. The power system is simulated with DIgSILENT Power Factory software and all calculations are performed by MATLAB. Numerous fault cases are conducted to demonstrate the efficacy of the proposed algorithm considering different values of fault resistances, different fault locations and all fault types. In addition, the effects of synchrophasors errors, measurement errors and the soil resistivity variations are investigated. The results of simulation prove the efficacy of the proposed algorithm for all fault cases.
Development of a Ratiometric Fluorescent Probe with Two ­Reactive Sulfoxides for Monitoring the Activity of Methionine Sulfoxide Reductase A
Authors: Míšek Jiří , Makukhin Nikolai , Nosek Vladimír
Published: January 2018

Biological oxidation of methionine side chains in proteins is a process that affects the functions of many proteins. One of the key regulators of this signaling is the enzyme methionine sulfoxide reductase A (MsrA). MsrA is implicated in a number of diseases, but detailed understanding of its function is hindered by the lack of tools for monitoring the enzyme’s activity. We have designed and synthesized a probe named (S,S)-Sulfox-2 that is based on a BODIPY fluorophore and is equipped with two chiral sulfoxide units of defined stereochemistry. (S,S)-Sulfox-2 is shown to be highly responsive to MsrA and allows tracing of the MsrA activity by a significant change in the fluorescence profile.
A Comparison of the Operative Techniques and the Postoperative Complications for Bone-Anchored Hearing Aid Implantation
Authors: Steehler Mark , Larner Sean , Mintz Joshua , Steehler Matthew , Lipman Sidney , Griffith Shane
Published: January 2018

Introduction Bone anchored hearing aids (BAHA) represent a useful surgical option for patients with single sided deafness.

Objectives To compare multiple techniques for BAHA implantation regarding postoperative complications, operative time, and duration between the surgery and the first use of the BAHA.

Methods A retrospective study was conducted of all patients receiving implantation of a BAHA from August of 2008 to October of 2014. Data collected included: patient age, gender, side operated, abutment length, operative time, duration until first use of the BAHA, operative technique, and postoperative complications. The statistical analysis was performed using analysis of variance (ANOVA), Tukey pairwise comparison, chi-square, and paired t-test. Statistical significance was determined using a level of p < 0.05.

Results A total of 88 patients (43 female and 45 male) were included in the data analysis. A total of 80 complications were documented, and these complications were classified according to the Holgers criteria. A significant difference in the total postoperative complications existed between the six techniques used (ANOVA; p < 0.01). In addition, there was also a significant difference among the six techniques employed regarding the operative time (ANOVA; p < 0.01). The average time duration until fitting of the BAHA processor among the various techniques trended toward but did not reach statistical significance (ANOVA; p = 0.16).

Conclusions Significant differences in the operative outcomes exist among the various techniques for BAHA implantation. Based on the statistical analysis of our data, the BAHA Attract system (Cochlear Ltd., Sidney, Australia) requires greater operative time, but it is associated with less postoperative complications than percutaneous techniques and its processor may be fitted significantly sooner.
Extended Retrosigmoid Approach for Cerebellopontine Angle Meningiomas: Operative Technique and Results—A Series of 28 Patients
Authors: Pereira Celestino , Welling Leonardo , Gonçalves Mariangela , Zanon Nelci , Lynch Jose
Published: January 2018

Background The purpose of this article is to describe our approach, surgical strategies, and results for resection of meningiomas located at cerebellopontine angle (CPA).

Methods We retrospectively identified 28 patients with CPA meningiomas operated by the extended retrosigmoid approach. This approach incorporates a generous mastoidectomy and the sigmoid sinus exposure.

Results The mean age was 33.8 years, with a follow-up of 12.5 years. Gross total removal (GTR) was achieved in 22 (78.5%) patients with low surgical mortality, acceptable morbidity, and recurrence rate of 7.1% (2 patients).

Conclusion The extended retrosigmoid approach enhances the exposure of the CPA and posterior fossa cisterns and increases the surgical angle of maneuverability. This approach provides adequate access even to extensive CPA meningiomas, enabling, in most of cases, GTR to be safe and effective. The extended retrosigmoid approach used in this group of patients is an alternative to more extensive cranial base approaches.
Ultra-Early Optic Nerve Decompression for the Resection of Anterior Clinoidal Meningioma
Authors: Oya Soichi , Matsui Toru
Published: January 2018

Improvement in vision is one of the main goals of surgery for anterior clinoidal meningiomas with visual deficits. Early optic nerve decompression surgery has been advocated in previous studies to achieve the best visual outcome. Through this video, the authors describe their surgical techniques to decompress the optic nerve at the very early stage of surgery.

A 35-year-old patient presented with subjective blurry vision in the right eye over the last 8 months. Magnetic resonance images showed a 3.2-cm meningioma arising at the right anterior clinoid. Preoperative ophthalmological test was within the normal range, but the patient wished to have surgical resection after a detailed discussion of benefits and risks related to surgical resection. The surgical strategy consisted of the right lateral subfrontal approach that includes a standard right frontotemporal craniotomy, extradural anterior clinoidectomy, and early optic nerve decompression prior to tumor resection. The tumor was divided into compartments defined by the arteries and resected. Simpson grade II resection was achieved without complications. The patient's symptoms disappeared.

In anterior clinoidal meningiomas that cause visual deficits, the optic nerve is assumed very vulnerable to any further injuries related to the operative maneuver. Ultra-early optic nerve decompression can be performed in anterior clinoidal meningiomas regardless of their size by extradural unroofing of the optic canal and sectioning of the optic canal sheath, which we believe contributes to better visual improvement.

The link to the video can be found at: https://youtu.be/RIFi4ecWAhQ.
Antimicrobial Chemotherapy has a Linear Relationship to the Proportion of Gram-Negative Isolates from Pediatric Burn Wounds
Authors: Welk Alexa , Herrnberger Myriam , Engel Veronika , Dennebaum Martin , von Sochaczewski Christina , Gehring Stephan
Published: January 2018

Wound infection in burns is a relevant cause of morbidity and mortality in children. We aimed to determine the relationship between antibacterial chemotherapy and Gram-negative burn wound colonization and infection. All children admitted to the pediatric intensive care unit for burn trauma from June 1, 2005 to January 31, 2013 were included. We obtained 141 wound samples, of which 88 (65.7%) showed growth of Gram-positive bacteria. Treatment with antimicrobial chemotherapy was necessary in 23 (31.1%) patients. The proportion of Gram-negative isolates seems to increase linear from 12.5% (95% confidence interval (CI): 4.4%–28.7%) without antibacterial chemotherapy to 36.8% (95% CI: 25.5%–49.6%) with one to 48.9% (95% CI: 35.3%–62.8%) with 2 antimicrobial agents. The Odds ratio for a Gram-negative isolate, in comparison to patients without antibacterial chemotherapy, increased from 4.083 (95% CI: 1.140–15.961) for one administered substance to 6.708 (95% CI: 1.832–26.786) if 2 or more were used.

Conclusion We found that antibacterial chemotherapy seems to facilitate burn wound colonization and results in an increased number of gram-negative isolates from children with burn wounds.
An investigation into the dielectric and electrical properties of LaErO3 and LaHoO3 rare earth perovskites
Authors: Siaï A. , Horchani Naifer K. , Férid M.
Published: January 2018

We have investigated the electrical and dielectric properties of rare earth perovskites-type oxide (LaErO3 and LaHoO3) by using impedance spectroscopy, respectively, over a frequency and temperature range of [0.6 kHz–8 MHz] and [673–973 K]. Both oxides crystallize in the orthorhombic structure but exhibit difference in lattice distortions. A correlation between structural properties and dielectric anisotropies is carried out. The analysis of Nyquist semicircles confirms the presence of bulk effects and non-Debye relaxation processes for both compounds. The activation energy, calculated using relaxation time and direct current conductivity models, was found to follow the Arrhenius law. The frequency dependence of alternative current conductivity is described by Jonscher's universal power law and shows that the conduction mechanism follows the non-overlapping small polaron tunneling model. The investigation of dielectric properties revealed that at low frequencies the dielectric constant was higher for LaHoO3 oxide than that for LaErO3. Modulus formalism examination demonstrates that the relaxation process of studied materials takes place via the hopping mechanism.
Central recirculation zones and instability waves in internal swirling flows with an annular entry
Authors: Wang Yanxing , Yang Vigor
Published: January 2018

The characteristics of the central recirculation zone and the induced instability waves of a swirling flow in a cylindrical chamber with a slip head end have been numerically investigated using the Galerkin finite element method. The effects of Reynolds number as well as swirl level adjusted by the injection angle were examined systematically. The results indicate that at a high swirl level the flow is characterized by an axisymmetric central recirculation zone (CRZ). The fluid in the CRZ takes on a solid-body rotation driven by the outer main flow through a free shear layer. Both the solid-body rotating central flow and the free shear layer provide the potential for the development of instability waves. When the injection angle increases beyond a critical value, the basic axisymmetric flow loses stability, and instability waves develop. In the range of Reynolds numbers considered in this study, three kinds of instability were identified: inertial waves in the central flow, and azimuthal and longitudinal Kelvin-Helmholtz waves in the free shear layer. These three types of waves interact with each other and mix together. The mode selection of the azimuthal waves depends strongly on the injection angle, through the perimeter of the free shear layer. Compared with the injection angle, the Reynolds number plays a minor role in mode selection. The flow topologies and characteristics of different flow states are analyzed in detail, and the dependence of flow states on the injection angle and Reynolds number is summarized. Finally, a linear analysis of azimuthal instabilities is carried out; it confirms the mode selection mechanisms demonstrated by the numerical simulation.
Skewed Lorentzian pulses and exponential frequency power spectra
Authors: Garcia O. E. , Theodorsen A.
Published: January 2018

Frequency power spectra due to a super-position of uncorrelated Lorentzian pulses with a random distribution of amplitudes are considered. For pulses with a constant duration, there is an exponential frequency spectrum which is independent of the degree of pulse overlap and the pulse amplitude distribution. The spectrum is furthermore shown to be unaffected by skewness of the Lorentzian pulses and even a random distribution of the pulse asymmetry parameter and its correlation with the pulse amplitude. This stochastic model provides new insight into the ubiquitous exponential spectra in fluids and magnetized plasmas exhibiting deterministic chaos, where non-linear advection processes lead to amplitude dependent steepening of smooth pulses.
Stochastic approach to simulation of evaporation-triggered multiple self-assembly of mixed metal nanoparticles and their variable superradiance
Authors: Tamura Mamoru , Okamoto Koichi , Tamada Kaoru , Iida Takuya
Published: January 2018

We developed a design principle for the evaporation-triggered heterogeneous assembly of different kinds of metal nanoparticles in a two-dimensional environment. A dynamic Monte Carlo simulation shows the formation of island structures of gold nanoparticles (gold islands) surrounded by smaller silver nanoparticles (silver matrix) during the evaporation of organic solvent from the dispersion liquid on the water surface. Our developed principle revealed the spontaneous change in multiple interactions between gold and silver nanoparticles owing to the presence or the absence of solvation repulsion, which plays a crucial role in the formation of gold islands in the silver matrix. Not only the randomly arranged gold islands, but also the surrounding silver matrix phase contributed to the wavelength-tunable light scattering enhanced by a factor of 102 due to the superradiance effect. These results will pave the way for the design of multicolored optical devices based on random plasmonics via controlled interparticle interactions.
Exciton diffusion in bifluorene single crystals studied by light induced transient grating technique
Authors: Baronas Paulius , Ščajev Patrik , Čerkasovas Vladislavas , Kreiza Gediminas , Adomėnas Povilas , Adomėnienė Ona , Kazlauskas Karolis , Adachi Chihaya , Juršėnas Saulius
Published: January 2018

Exciton diffusion is considered to be of prime importance for controlling the recombination zone in organic light emitting devices. This is particularly relevant for organic lasers based on single crystals, where undesirable exciton-exciton annihilation at high concentrations is inevitable. Here, exciton diffusion is studied in bifluorene single crystals specifically designed for organic laser applications, therefore featuring exceptionally low threshold of light amplification. The non-destructive light induced transient grating (LITG) technique capable of simultaneously evaluating the exciton lifetime and diffusion coefficient along different directions of the crystal was employed for this study. Highly anisotropic singlet exciton diffusion with the diffusion coefficient varying from <0.05 up to 0.96 cm2/s (in a perpendicular direction) and the corresponding diffusion lengths changing from <60 up to 300 nm, respectively, was revealed in ethylene-bridged bifluorene crystals. The LITG results on the directionality of exciton diffusion are anticipated to be essential for devising single crystal based organic lasers.
Impact of surface energy on the shock properties of granular explosives
Authors: Bidault X. , Pineau N.
Published: January 2018

This paper presents the first part of a two-fold molecular dynamics study of the impact of the granularity on the shock properties of high explosives. Recent experimental studies show that the granularity can have a substantial impact on the properties of detonation products {i.e., variations in the size distributions of detonation nanodiamonds [V. Pichot et al., Sci. Rep. 3, 2159 (2013)]}. These variations can have two origins: the surface energy, which is a priori enhanced from micro- to nano-scale, and the porosity induced by the granular structure. In this first report, we study the impact of the surface-energy contribution on the inert shock compression of TATB, TNT, α-RDX, and β-HMX nano-grains (triaminotrinitrobenzene, trinitrotoluene, hexogen and octogen, respectively). We compute the radius-dependent surface energy and combine it with an ab initio-based equation of state in order to obtain the resulting shock properties through the Rankine-Hugoniot relations. We find that the enhancement of the surface energy results in a moderate overheating under shock compression. This contribution is minor with respect to porosity, when compared to a simple macroscopic model. This result motivates further atomistic studies on the impact of nanoporosity networks on the shock properties.
van der Waals epitaxy of Al-doped ZnO film on mica as a flexible transparent heater with ultrafast thermal response
Authors: Ke Shanming , Xie Jing , Chen Chang , Lin Peng , Zeng Xierong , Shu Longlong , Fei Linfeng , Wang Yu , Ye Mao , Wang Danyang
Published: January 2018

In this paper, high-performance conducting Al-doped ZnO (AZO) electrodes were deposited on transparent and flexible muscovite mica substrates. The use of mica as a substrate material makes a van der Waals epitaxy possible, which significantly improves the structural, electrical, and optical properties of deposited AZO single-crystal-like films. AZO/mica retains its low electric resistivity, even after continuous bending of up to 1000 times on account of the unique layered structure of mica. When used as a transparent heater, AZO/mica shows an ultrahigh heating rate (200 °C/s) across large areas, which is a record among flexible transparent heaters.
Low frequency and broadband metamaterial absorber with cross arrays and a flaked iron powder magnetic composite
Authors: Li Wangchang , Liu Qing , Wang Liwei , Zhou Zuzhi , Zheng Jingwu , Ying Yao , Qiao Liang , Yu Jing , Qiao Xiaojing , Che Shenglei
Published: January 2018

In this paper, we present a design, simulation and experimental measurement of a cross array metamaterial absorber (MMA) based on the flaked Carbonyl iron powder (CIP) filled rubber plate in the microwave regime. The metamaterial absorber is a layered structure consisting of multilayer periodic cross electric resonators, magnetic rubber plate and the ground metal plate. The MMA exhibits dual band absorbing property and the absorption can be tuned from 1∼8GHz in the same thickness depending on the dimension and position of the cross arrays. The obviously broadened absorbing band of the designed structure is a result of the synergistic effects of the electrical resonance of the cross arrays and intrinsic absorption of the magnetic layer. The polarization and oblique incident angle in TE and TM model are also investigated in detail to explore the absorbing mechanisms. The resonance current of the cross array can excite the enhanced local magnetic field and dielectric field which can promote the absorption. The measurement results are basically consistent with the simulations but the absorbing peaks move a little bit to higher frequency for the reason that the surface oxidation of the flaked CIP in the preparation process.
Continuum percolation of polydisperse rods in quadrupole fields: Theory and simulations
Authors: Finner Shari P. , Kotsev Mihail I. , Miller Mark A. , van der Schoot Paul
Published: January 2018

We investigate percolation in mixtures of nanorods in the presence of external fields that align or disalign the particles with the field axis. Such conditions are found in the formulation and processing of nanocomposites, where the field may be electric, magnetic, or due to elongational flow. Our focus is on the effect of length polydispersity, which—in the absence of a field—is known to produce a percolation threshold that scales with the inverse weight average of the particle length. Using a model of non-interacting spherocylinders in conjunction with connectedness percolation theory, we show that a quadrupolar field always increases the percolation threshold and that the universal scaling with the inverse weight average no longer holds if the field couples to the particle length. Instead, the percolation threshold becomes a function of higher moments of the length distribution, where the order of the relevant moments crucially depends on the strength and type of field applied. The theoretical predictions compare well with the results of our Monte Carlo simulations, which eliminate finite size effects by exploiting the fact that the universal scaling of the wrapping probability function holds even in anisotropic systems. Theory and simulation demonstrate that the percolation threshold of a polydisperse mixture can be lower than that of the individual components, confirming recent work based on a mapping onto a Bethe lattice as well as earlier computer simulations involving dipole fields. Our work shows how the formulation of nanocomposites may be used to compensate for the adverse effects of aligning fields that are inevitable under practical manufacturing conditions.
The Laser ablation of a metal foam: The role of electron–phonon coupling and electronic heat diffusivity
Authors: Rosandi Yudi , Grossi Joás , Bringa Eduardo M. , Urbassek Herbert M.
Published: January 2018

The incidence of energetic laser pulses on a metal foam may lead to foam ablation. The processes occurring in the foam may differ strongly from those in a bulk metal: The absorption of laser light, energy transfer to the atomic system, heat conduction, and finally, the atomistic processes—such as melting or evaporation—may be different. In addition, novel phenomena take place, such as a reorganization of the ligament network in the foam. We study all these processes in an Au foam of average porosity 79% and an average ligament diameter of 2.5 nm, using molecular dynamics simulation. The coupling of the electronic system to the atomic system is modeled by using the electron–phonon coupling, g, and the electronic heat diffusivity, κe, as model parameters, since their actual values for foams are unknown. We show that the foam coarsens under laser irradiation. While κe governs the homogeneity of the processes, g mainly determines their time scale. The final porosity reached is independent of the value of g.
Numerical investigation on the field emission properties of N-doped graphdiyne-C60 nanostructures
Authors: Dai Xuanjun , Ge Daohan
Published: January 2018

A new N-doped graphdiyne-C60 nanostructure was constructed to explore the electronic structure and field emission characteristics. Using density functional theory (DFT), the geometric configuration is optimized and then the corresponding energy of this nanostructure was calculated by considering N-doping. The field emission mechanism has been analyzed through energy gaps change between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), local electron density distribution, and mulliken population analysis. Owing to the doping of nitrogen atom, the local electron states is generated, and increased at the Fermi level dramatically. The results show that the N-doped graphdiyne-C60 compound has stable structure and excellent semiconducting properties. The calculated work function (WF) and ionization potential (IP) of N-doped graphdiyne-C60 nanostructure decrease significantly when compared with pristine graphdiyne-C60 composite. The field emission properties of graphdiyne-C60 can be boosted by the doping nitrogen atom, which provides a potential application for N-doped graphdiyne-C60 nanostructures as a field emission cathode in field emission devices.
The role of the global phase in the spatio-temporal evolution of strong-coupling Brillouin scattering
Authors: Amiranoff F. , Riconda C. , Chiaramello M. , Lancia L. , Marquès J. R. , Weber S.
Published: January 2018

The role of the global phase in the spatio-temporal evolution of the 3-wave coupled equations for backscattering is analyzed in the strong-coupling regime of Brillouin scattering. This is of particular interest for controlled backscattering in the case of plasma-based amplification to produce short and intense laser pulses. It is shown that the analysis of the envelope equations of the three waves involved, pump, seed, and ion wave, in terms of phase and amplitude fully describes the coupling dynamics. In particular, it helps understanding the role of the chirp of the laser beams and of the plasma density profile. The results can be used to optimize or quench the coupling mechanism. It is found that the directionality of the energy transfer is imposed by the phase relation at the leading edge of the pulse. This actually ensures continued energy transfer even if the intensity of the seed pulse is already higher than the pump pulse intensity.
Image quality assessment metric for frame accumulated image
Authors: Yu Jianping , Li Gang , Wang Shaohui , Lin Ling
Published: January 2018

The medical image quality determines the accuracy of diagnosis, and the gray-scale resolution is an important parameter to measure image quality. But current objective metrics are not very suitable for assessing medical images obtained by frame accumulation technology. Little attention was paid to the gray-scale resolution, basically based on spatial resolution and limited to the 256 level gray scale of the existing display device. Thus, this paper proposes a metric, “mean signal-to-noise ratio” (MSNR) based on signal-to-noise in order to be more reasonable to evaluate frame accumulated medical image quality. We demonstrate its potential application through a series of images under a constant illumination signal. Here, the mean image of enough images was regarded as the reference image. Several groups of images by different frame accumulation and their MSNR were calculated. The results of the experiment show that, compared with other quality assessment methods, the metric is simpler, more effective, and more suitable for assessing frame accumulated images that surpass the gray scale and precision of the original image.
CuInS2/ZnS QD-ferroelectric liquid crystal mixtures for faster electro-optical devices and their energy storage aspects
Authors: Singh Dharmendra Pratap , Vimal Tripti , Mange Yatin J. , Varia Mahesh C. , Nann Thomas , Pandey K. K. , Manohar Rajiv , Douali Redouane
Published: January 2018

CuInS2/ZnS core/shell quantum dots (CIS/ZnS QDs) dispersed ferroelectric liquid crystal (FLC) mixtures have been characterized for their application in electro-optical devices, energy storage, and solar cells. Physical properties of the CIS/ZnS QD-FLC (ferroelectric liquid crystal) mixtures have also been investigated with varying QD concentrations in order to optimize the critical concentration of QDs in mixtures. The presence of QDs breaks the geometrical symmetry in the FLC matrix, which results in a change in the physical properties of the mixtures. We observed the reduced values of primary and secondary order parameters (tilt angle and spontaneous polarization, respectively) for mixtures, which also depend on the concentration of QDs. The reduction of spontaneous polarization in QDs-FLC mixtures is attributed to the adverse role of flexoelectric contribution in the mixtures. The 92% faster electro-optic response and enhanced capacitance indicate the possible application of these mixtures in electro-optical devices and solar cells. Photoluminescence emission of pure FLC and QDs-FLC mixtures has been thermally tailored, which is explained by suitable models.
Feeding habits of bigeye tuna (Thunnus obesus) in the North Pacific from 2011 to 2013
Authors: Ohshimo Seiji , Hiraoka Yuko , Sato Takuya , Nakatsuka Sayaka
Published: January 2018

In the present study, we analysed the stomach contents of 585 bigeye tuna (BET; Thunnus obesus) caught in the Kuroshio–Oyashio transition zone, a high-productivity region in the western North Pacific Ocean, to describe feeding habits and prey size. We identified 46 prey species belonging to 40 genera. Fish otoliths and squid beaks found in stomachs were used to calculate prey body length and weight from allometric relationships. The percentage index of relative importance (%IRI) was calculated from the mean percentage of occurrence, number and weight of each prey species. Squid and fish were the main prey of BET in the sampling area and the highest %IRI prey species during the survey was Eucleoteuthis luminosa (luminous flying squid; 7.6%), followed by Gonatopsis makko (mako armhook squid; 4.8%) and Magnisudis atlantica (duckbill barracudina; 2.3%). The %IRI of E. luminosa decreased and that of M. atlantica increased with increasing BET body length. The size of prey fish increased with increasing BET size, whereas the size of prey squid was similar across BET size. The results indicate ontogenetic shifts in the feeding habits of BET in the study area. These data provide fundamental information that will improve our understanding of oceanic food webs in the Kuroshio–Oyashio transition zone, an important foraging area for many pelagic species.
Rotational 3D printing of damage-tolerant composites with programmable mechanics
Authors: Raney Jordan R. , Compton Brett G. , Mueller Jochen , Ober Thomas J. , Shea Kristina , Lewis Jennifer A.
Published: January 2018

Significance

Natural composites exhibit hierarchical and spatially varying structural features that give rise to high stiffness and strength as well as damage tolerance. Here, we report a rotational 3D printing method that enables exquisite control of fiber orientation within engineered composites. Our approach broadens their design, microstructural complexity, and performance space by enabling site-specific optimization of fiber arrangements within short carbon fiber–epoxy composites. Using this approach, we have created composites with programmable strain distribution and failure as well as enhanced damage tolerance.
Infectious virus in exhaled breath of symptomatic seasonal influenza cases from a college community
Authors: Yan Jing , Grantham Michael , Pantelic Jovan , Bueno de Mesquita P. Jacob , Albert Barbara , Liu Fengjie , Ehrman Sheryl , Milton Donald K. ,   EMIT Consortium, Adamson Walt , Beato-Arribas Blanca , Bischoff Werner , Booth William , Cauchemez Simon , Ehrman Sheryl , Enstone Joanne , Ferguson Neil , Forni John , Gilbert Anthony , Grantham Michael , Grohskopf Lisa , Hayward Andrew , Hewitt Michael , Kang Ashley , Killingley Ben , Lambkin-Williams Robert , Mann Alex , Milton Donald , Nguyen-Van-Tam Jonathan , Noakes Catherine , Oxford John , Palmarini Massimo , Pantelic Jovan , Wang Jennifer , Bennett Allan , Cowling Ben , Monto Arnold , Tellier Raymond
Published: January 2018

Significance

Lack of human data on influenza virus aerosol shedding fuels debate over the importance of airborne transmission. We provide overwhelming evidence that humans generate infectious aerosols and quantitative data to improve mathematical models of transmission and public health interventions. We show that sneezing is rare and not important for—and that coughing is not required for—influenza virus aerosolization. Our findings, that upper and lower airway infection are independent and that fine-particle exhaled aerosols reflect infection in the lung, opened a pathway for a deeper understanding of the human biology of influenza infection and transmission. Our observation of an association between repeated vaccination and increased viral aerosol generation demonstrated the power of our method, but needs confirmation.
Origins of low-symmetry phases in asymmetric diblock copolymer melts
Authors: Kim Kyungtae , Arora Akash , Lewis Ronald M. , Liu Meijiao , Li Weihua , Shi An-Chang , Dorfman Kevin D. , Bates Frank S.
Published: January 2018

Significance

We demonstrate that low-molecular weight asymmetric diblock copolymer melts can form multiple metastable liquid states at a common temperature, dependent on the processing history. Formation of ordered self-assembled micelles at low temperatures shapes the number density of the mesoscopic particles, which is preserved upon heating above the order–disorder transition temperature. Cooling returns the liquid to the same crystalline state reflecting a memory—a type of hidden symmetry—imprinted in the fluid. These surprising results are explained based on the large energetic penalty associated with fusing or fragmenting micelles in the highly structured liquid state. This work reveals concepts related to spontaneous symmetry breaking in self-assembled soft materials including surfactant-based systems.