bluuebunny/crossref_metadata_2025 huggingface dataset:
Complex solutions of the Dean equations and non-uniqueness at all Reynolds numbers
Authors: Boshier F. A. T. , Mestel A. J.
Published: March 2017

Steady incompressible flow down a slowly curving circular pipe is considered, analytically and numerically. Both real and complex solutions are investigated. Using high-order Hermite–Padé approximants, the Dean series solution is analytically continued outside its circle of convergence, where it predicts a complex solution branch for real positive Dean number, $K$. This is confirmed by numerical solution. It is shown that other previously unknown solution branches exist for all $K>0$, which are related to an unforced complex eigensolution. This non-uniqueness is believed to be generic to the Navier–Stokes equations in most geometries. By means of path continuation, numerical solutions are followed around the complex $K$-plane. The standard Dean two-vortex solution is shown to lie on the same hypersurface as the eigensolution and the four-vortex solutions found in the literature. Elliptic pipes are considered and shown to exhibit similar behaviour to the circular case. There is an imaginary singularity limiting convergence of the Dean series, an unforced solution at $K=0$ and non-uniqueness for $K>0$, culminating in a real bifurcation.
Normalized dissipation rate in a moderate Taylor Reynolds number flow
Authors: Puga Alejandro J. , LaRue John C.
Published: March 2017

Time-resolved velocity measurements are obtained using a hot-wire in a nearly homogeneous and isotropic flow downstream of an active grid for a range of Taylor Reynolds numbers from$191$to$659$. It is found that the dimensionless dissipation rate,$C_{\unicode[STIX]{x1D716}}$, is nearly a constant for sufficiently high values of Taylor Reynolds number,$R_{\unicode[STIX]{x1D706},u_{q}}$, and is approximately equal to$0.87$. This value is approximately$5\,\%$less than the value reported by Boset al.(Phys. Fluids, vol. 19 (4), 2007, 045101), which is obtained using DNS/LES (direct numerical simulation combined with large eddy simulation) for decaying homogeneous and isotropic turbulence, and is in excellent agreement with the active grid experiment of Thormann & Meneveau (Phys. Fluids, vol. 26 (2), 2014, 025112.). The results presented herein show that deviation from isotropy may cause inconsistencies in the computation of$C_{\unicode[STIX]{x1D716}}$. As a result, it is suggested that the velocity scale be the square root of the turbulence kinetic energy. The integral length scale measurements obtained from the longitudinal velocity correlation are in close agreement with the integral length scale measured from the peak of the energy spectrum,$\unicode[STIX]{x1D705}E_{11}(\unicode[STIX]{x1D705})$, where$\unicode[STIX]{x1D705}$is the wavenumber and$E_{11}(\unicode[STIX]{x1D705})$is the one-dimensional power spectrum of the downstream velocity.
The topology of gas jets injected beneath a surface and subject to liquid cross-flow
Authors: Mäkiharju Simo A. , Lee In-Ho R. , Filip Grzegorz P. , Maki Kevin J. , Ceccio Steven L.
Published: March 2017

Gas injection into a liquid cross-flow is examined for the case where the gas is injected beneath a horizontal flat surface. For moderate Froude numbers, the gas pocket that is formed will rise toward the flow boundary under the action of buoyancy, a condition that is conducive to the formation of gas layers for friction-drag reduction on the surface. At the location of gas injection, a plume whose geometry is related to the mass and momentum flux of the injected gas and liquid cross-flow is formed, and the influence of buoyancy is minimal. However, as the gas pocket convects downstream, buoyancy brings the gas back upward to the flow boundary, and leads to the bifurcation of the pocket into two distinct branches, forming a stable ‘V’-shape. Under some conditions, the flow between the two gas branches is almost entirely liquid, while for others there exists a bubbly flow or a continuous sheet of gas between the branches. The sweep angle and cross-sectional geometry of the gas branches are related to free-stream speed and boundary-layer thickness of the liquid cross-flow, the mass-injection rate of the gas, the diameter of the injection orifice and the gas outlet mean velocity and gas–jet angle. Data for a range of experimental conditions are used to scale the flow and results are compared to numerical computations of the flow, and these data are used to illustrate the underlying flow processes responsible leading to the formation the stable and straight gas branches. A simple model based on the balance of forces around a stable gas branch is presented and used to scale the observed data, and we use the results of this analysis and the computations to discuss how the process of gas injection may interact with the formation of the stable gas pockets farther downstream.
IDENTIFYING DOMESTIC CERAMIC PRODUCTION IN THE MAYA LOWLANDS: A CASE STUDY FROM UXBENKA, BELIZE
Authors: Jordan Jillian M. , Prufer Keith M.
Published: March 2017

Utilitarian ceramic vessels form the bulk of artifact assemblages in the Maya Lowlands, but little is known about their production beyond the likelihood that they were made in a domestic context without elite involvement. Characterizing the production and distribution of these vessels is vital to understanding ancient Maya economic systems; nevertheless, this is a difficult task in the absence of primary production locales. We use spatial data, use-wear analyses on stone and ceramic tools, and analyses of finished products to identify households involved in ceramic production at three settlement groups at Uxbenka, Belize, during the Late Classic Period (A.D. 600–800). Our analyses indicate that Uxbenka potters were likely involved in some level of residential specialization focused on specific vessel forms. These data, in conjunction with ceramic data from nearby Lubaantun and Nim Li Punit, suggest that all three polities were self-sufficient in terms of utilitarian pottery production and primarily engaged in intrapolity distribution. We argue that this self-sufficiency is due to widely available resources, smaller population sizes, and the availability of high quality agricultural lands.
KNOCK! KNOCK! WHO'S THERE? AN ETHNOARCHAEOLOGICAL APPROACH IN FRENCH GUIANA
Authors: Rostain Stéphen
Published: March 2017

Amazonia and the Guianas possess exceptional potential for ethnoarchaeological studies because of the precolumbian heritage of modern-day Amerindian people. Surprisingly, minimal scholarship of this nature has been conducted in the South American lowlands. On the French Guiana coast, Maillard, a small Palikur village, was abruptly abandoned in 1990. I initiated an ethnoarchaeological study to pinpoint important differences between the interpretation of archaeological and ethnographic data. I recorded the topography of features and remains, compiled an inventory of artifacts and the contents of discard areas, inventoried the cultivated trees present, and described the characteristics of the surroundings. After analyzing the data using classical methods of archaeological inference to obtain a complete reconstruction of the village and the customs of its inhabitants, I invited the chief into his now-abandoned village to describe the settlement as it was while inhabited. In the twenty years since, I have made several visits to track the natural degradation of the site. This ethnoarchaeological approach shows that archaeologists dealing with field data can make many mistakes. Conversely, ethnographic accounts are distorted by the cultural rules and interdictions of interviewees. This experiment suggests the need for prudence in our interpretations and hypotheses, especially in the tropical lowlands, where archaeological preservation is particularly poor.
EDITOR'S CORNER
Authors: Braswell Geoffrey E. , Gutiérrez María
Published: March 2017

The March 2017 issue of Latin American Antiquity brings with it momentous changes. It also marks the conclusion of our first term as coeditors. We think it important to let you know how LAQ has grown this decade and especially over the past three years, and to inform you of significant changes that commence with this issue.
THE ROLE OF DOMINATION AND SMOOTHING CONDITIONS IN THE THEORY OF EVENTUALLY POSITIVE SEMIGROUPS
Authors: DANERS DANIEL , GLÜCK JOCHEN
Published: March 2017

We carry out an in-depth study of some domination and smoothing properties of linear operators and of their role within the theory of eventually positive operator semigroups. On the one hand, we prove that, on many important function spaces, they imply compactness properties. On the other hand, we show that these conditions can be omitted in a number of Perron–Frobenius type spectral theorems. We furthermore prove a Kreĭn–Rutman type theorem on the existence of positive eigenvectors and eigenfunctionals under certain eventual positivity conditions.
Phenotypic and molecular characteristics ofStaphylococcus aureusand methicillin-resistantStaphylococcus aureusin slaughterhouse pig-related workers and control workers in Guangdong Province, China
Authors: WANG X. L. , LI L. , LI S. M. , HUANG J. Y. , FAN Y. P. , YAO Z. J. , YE X. H. , CHEN S. D.
Published: March 2017

Pig farmers and veterinarians have high prevalence of methicillin-resistantStaphylococcus aureus(MRSA) due to the occupational livestock exposure, while few reported this association on slaughterhouse workers. We conducted this cross-sectional study to explore the phenotypic and molecular characteristics ofS. aureusand MRSA in slaughterhouse pig-related workers and control workers in Guangdong Province, China. Participants were interviewed and provided two nasal swabs. Swabs were tested forS. aureus, and isolates were further tested for antimicrobial susceptibility, virulence genes and multi-locus sequence typing. Compared with control workers, pig-related workers have significantly higher prevalence of MRSA carriage (adjusted odd ratio (aOR) 3·70, 95% CI 1·63–8·40). The proportions of MRSA resistant to clindamycin, erythromycin, tetracycline or chloromycetin were significantly higher in pig-related workers than in control workers. The predominant phenotypes ofS. aureuswere resistant to penicillin, clindamycin, erythromycin and tetracycline. Three MRSA CC9 isolates with livestock-associated characteristics (resistance to tetracycline and absence of immune evasion cluster (IEC) genes) were detected in pig-related workers but not in control workers. For human-associated CCs (CC7, CC59, CC6, and CC188), there was no significant difference in IEC profile or antimicrobial resistance between the groups. These findings reveal that there may be a potential risk for livestock-to-human transmission of LA-MRSA and human-to-human transmission of human-associated MRSA.
The role of contextual frequency in the articulation of initial /f/ in Modern Spanish: The same effect as in the reduction of Latin /f/?
Authors: Brown Earl K. , Alba Matthew C.
Published: March 2017

The acoustic energy of 996 tokens of word-initial /f/ in the speech of 38 speakers of Mexican Spanish was analyzed. The results suggest that the frequency with which words occur in phonological contexts favorable to reduction (Frequency in a Reducing Context or FRC) conditions the reduction of /f/, even after taking into account the immediate phonological context. Despite this, it is also found that the conditioning effect of FRC is less robust than the influence of the immediate phonological context, thus confirming the preeminence in these data of the online articulatory factors in comparison to the usage-based frequency factors.
THE TWO-ARC-TRANSITIVE GRAPHS OF SQUARE-FREE ORDER ADMITTING ALTERNATING OR SYMMETRIC GROUPS
Authors: WANG GAI XIA , LU ZAI PING
Published: March 2017

Let $G$ be a finite group with $\mathsf{soc}(G)=\text{A}_{c}$ for $c\geq 5$. A characterization of the subgroups with square-free index in $G$ is given. Also, it is shown that a $(G,2)$-arc-transitive graph of square-free order is isomorphic to a complete graph, a complete bipartite graph with a matching deleted or one of $11$ other graphs.
SOME RESULTS ON AN ALGEBRO-GEOMETRIC CONDITION ON GRAPHS
Authors: KULKARNI AVI , MAXEDON GREGORY , YEATS KAREN
Published: March 2017

Paolo Aluffi, inspired by an algebro-geometric problem, asked when the Kirchhoff polynomial of a graph is in the Jacobian ideal of the Kirchhoff polynomial of the same graph with one edge deleted. We give some results on which graph–edge pairs have this property. In particular, we show that multiple edges can be reduced to double edges, we characterize which edges of wheel graphs satisfy the property, we consider a stronger condition which guarantees the property for any parallel join, and we find a class of series–parallel graphs with the property.
LIBERAL INTELLECTUAL CULTURE AND RELIGIOUS FAITH: THE LIBERALISM OF THE NEW YORK LIBERAL CLUB, 1869–1877
Authors: Shubitz Scott M.
Published: March 2017

This essay addresses the question of how the idea of liberalism and antireligious sentiment became associated during the Gilded Age. The subject of this essay—the New York Liberal Club, a debate and lecture group in New York City (1869–1877)—sheds light on the process in which liberalism, as an idea, outgrew its religious origins in early nineteenth-century America and more than ever became linked with antireligious sentiment. In the case of the New York Liberal Club, this development owed to the club's connection to social science and members' participation in the contentious debate over science and religion during the 1870s. In addition, it partly owed to club members' conception of liberalism as tolerance, open-mindedness, and a commitment to the free exchange of ideas. Because of this conception of liberalism, many club members saw liberalism and social science as a common cause, since both reflected a dedication to improving the world through free inquiry. Ultimately, these conceptions, as well as discourse at the club, led many observers in the public to incorrectly view all Liberal Club members (and liberalism itself) as in opposition to faith and religious belief.
Electrical brain stimulation induces dendritic stripping but improves survival of silent neurons after optic nerve damage
Authors: Henrich-Noack Petra , Sergeeva Elena G. , Eber Torben , You Qing , Voigt Nadine , Köhler Jürgen , Wagner Sebastian , Lazik Stefanie , Mawrin Christian , Xu Guihua , Biswas Sayantan , Sabel Bernhard A. , Leung Christopher Kai-Shun
Published: March 2017

Repetitive transorbital alternating current stimulation (rtACS) improves vision in patients with chronic visual impairments and an acute treatment increased survival of retinal neurons after optic nerve crush (ONC) in rodent models of visual system injury. However, despite this protection no functional recovery could be detected in rats, which was interpreted as evidence of “silent survivor” cells. We now analysed the mechanisms underlying this “silent survival” effect. Usingin vivomicroscopy of the retina we investigated the survival and morphology of fluorescent neurons before and after ONC in animals receiving rtACS or sham treatment. One week after the crush, more neurons survived in the rtACS-treated group compared to sham-treated controls.In vivoimaging further revealed that in the initial post-ONC period, rtACS induced dendritic pruning in surviving neurons. In contrast, dendrites in untreated retinae degenerated slowly after the axonal trauma and neurons died. The complete loss of visual evoked potentials supports the hypothesis that cell signalling is abolished in the surviving neurons. Despite this evidence of “silencing”, intracellular free calcium imaging showed that the cells were still viable. We propose that early after trauma, complete dendritic stripping following rtACS protects neurons from excitotoxic cell death by silencing them.
Improving the Efficiency and Effectiveness of Community Detection via Prior-Induced Equivalent Super-Network
Authors: Yang Liang , Jin Di , He Dongxiao , Fu Huazhu , Cao Xiaochun , Fogelman-Soulie Francoise
Published: March 2017

Due to the importance of community structure in understanding network and a surge of interest aroused on community detectability, how to improve the community identification performance with pairwise prior information becomes a hot topic. However, most existing semi-supervised community detection algorithms only focus on improving the accuracy but ignore the impacts of priors on speeding detection. Besides, they always require to tune additional parameters and cannot guarantee pairwise constraints. To address these drawbacks, we propose a general, high-speed, effective and parameter-free semi-supervised community detection framework. By constructing the indivisible super-nodes according to the connected subgraph of the must-link constraints and by forming the weighted super-edge based on network topology and cannot-link constraints, our new framework transforms the original network into an equivalent but much smaller Super-Network. Super-Network perfectly ensures the must-link constraints and effectively encodes cannot-link constraints. Furthermore, the time complexity of super-network construction process is linear in the original network size, which makes it efficient. Meanwhile, since the constructed super-network is much smaller than the original one, any existing community detection algorithm is much faster when using our framework. Besides, the overall process will not introduce any additional parameters, making it more practical.
Ultra-High Mass Resolution MALDI Imaging Mass Spectrometry of Proteins and Metabolites in a Mouse Model of Glioblastoma
Authors: Dilillo M. , Ait-Belkacem R. , Esteve C. , Pellegrini D. , Nicolardi S. , Costa M. , Vannini E. , Graaf E. L. de , Caleo M. , McDonnell L. A.
Published: March 2017

MALDI mass spectrometry imaging is able to simultaneously determine the spatial distribution of hundreds of molecules directly from tissue sections, without labeling and without prior knowledge. Ultra-high mass resolution measurements based on Fourier-transform mass spectrometry have been utilized to resolve isobaric lipids, metabolites and tryptic peptides. Here we demonstrate the potential of 15T MALDI-FTICR MSI for molecular pathology in a mouse model of high-grade glioma. The high mass accuracy and resolving power of high field FTICR MSI enabled tumor specific proteoforms, and tumor-specific proteins with overlapping and isobaric isotopic distributions to be clearly resolved. The protein ions detected by MALDI MSI were assigned to proteins identified by region-specific microproteomics (0.8 mm2 regions isolated using laser capture microdissection) on the basis of exact mass and isotopic distribution. These label free quantitative experiments also confirmed the protein expression changes observed by MALDI MSI and revealed changes in key metabolic proteins, which were supported by in-situ metabolite MALDI MSI.
Preventing microbial biofilms on catheter tubes using ultrasonic guided waves
Authors: Wang Huanlei , Teng Fengmeng , Yang Xin , Guo Xiasheng , Tu Juan , Zhang Chunbing , Zhang Dong
Published: March 2017

Biofilms on indwelling tubes and medical prosthetic devices are among the leading causes of antibiotic-resistant bacterial infections. In this work, a new anti-biofilm catheter prototype was proposed. By combining an endotracheal tube (ET) with a group of ultrasonic guided wave (UGW) transducers, the general idea was to prevent bacteria aggregation with UGW vibrations. Based on quantitative analysis of UGW propagation, detailed approach was achieved through (a) selection of ultrasonic frequency, wave modes and vibration amplitude; and (b) adoption of wave coupling and 45° wave incidence technique. Performance of the proposed UGW-ET prototype was demonstrated viain vitroexperiments, during which it deterred deposition ofPseudomonas aeruginosa(P. aeruginosa) biofilms successfully. With current configuration, UGW amplitudes ranged from 0.05–5 nm could be optimal to achieve biofilm prevention. This work sheds a light in the underlying mechanism of ultrasound-mediated biofilm prevention, and will inspire the development of new catheters of better antibacterial capability.
RETRACTED ARTICLE: Birinapant sensitizes platinum-resistant carcinomas with high levels of cIAP to carboplatin therapy
Authors: La V. , Fujikawa R. , Janzen D. M. , Nunez M. , Bainvoll L. , Hwang L. , Faull K. , Lawson G. , Memarzadeh S.
Published: March 2017

Platinum drugs are the frontline therapy in many carcinomas, including high-grade serous ovarian cancers. Clinically, high-grade serous carcinomas have an apparent complete response to carboplatin, but tumors invariably recur and response to platinum drugs diminishes over time. Standard of care prohibits re-administration of platinum drugs to these patients who are labeled as having platinum-resistant disease. In this stage patients are treated with non-platinum agents and outcomes are often poor. In vivo and in vitro data presented here demonstrate that this clinical dogma should be challenged. Platinum drugs can be an effective therapy even for platinum-resistant carcinomas as long as they are combined with an agent that specifically targets mechanisms of platinum resistance exploited by the therapy-resistant tumor subpopulations. High levels of cellular inhibitor of apoptosis proteins cIAP1 and 2 (cIAP) were detected in up to 50% of high-grade serous and non-high-grade serous platinum-resistant carcinomas. cIAP proteins can induce platinum resistance and they are effectively degraded with the drug birinapant. In platinum-resistant tumors with ≥22.4 ng of cIAP per 20 µg of tumor lysate, the combination of birinapant with carboplatin was effective in eliminating the cancer. Our findings provide a new personalized therapeutic option for patients with platinum-resistant carcinomas. The efficacy of birinapant in combination with carboplatin should be tested in high-grade serous carcinoma patients in a clinical trial.
Epigenetic modification of nucleic acids: from basic studies to medical applications
Authors: Chen Yuqi , Hong Tingting , Wang Shaoru , Mo Jing , Tian Tian , Zhou Xiang
Published: March 2017

This review focuses on the recent progresses in epigenetic modifications in DNA and RNA, including their epigenetic roles, detection methods and applications in clinical medicine.
Edge functionalized germanene nanoribbons: impact on electronic and magnetic properties
Authors: Monshi M. M. , Aghaei S. M. , Calizo I.
Published: March 2017

The spin-polarized calculations of fluorinated a11doped with a B atom indicate that it is semiconducting in both channels with band gaps of 0.4254 and 0.3932 eV for spin-up (α) and spin-down (β) channels.
A simple colorimetric and fluorescent probe with high selectivity towards cysteine over homocysteine and glutathione
Authors: Guo Jing , Kuai Ziyu , Zhang Zhixiang , Yang Qingbiao , Shan Yaming , Li Yaoxian
Published: March 2017

A novel turn-on fluorescent sensor AQDA with high selective towards cysteine.
Site-selective benzoin-type cyclization of unsymmetrical dialdoses catalyzed by N-heterocyclic carbenes for divergent cyclitol synthesis
Authors: Kang Bubwoong , Wang Yinli , Kuwano Satoru , Yamaoka Yousuke , Takasu Kiyosei , Yamada Ken-ichi
Published: March 2017

A highly site-selective NHC-catalyzed benzoin-type cyclization of unsymmetrical dialdoses was achieved.
Gold-catalyzed oxidative couplings of two indoles with one aryldiazo cyanide under oxidant-free conditions
Authors: Singh RahulKumar Rajmani , Liu Rai-Shung
Published: March 2017

In the absence of external oxidants, gold-catalyzed oxidative couplings of two indoles with one phenyldiazo cyanide are described; these annulations work well with a good range of diazo and indole species.
Enhancing thermoelectric performance in hierarchically structured BiCuSeO by increasing bond covalency and weakening carrier–phonon coupling
Authors: Ren Guang-Kun , Wang Shan-Yu , Zhu Ying-Cai , Ventura Kyle J. , Tan Xing , Xu Wei , Lin Yuan-Hua , Yang Jihui , Nan Ce-Wen
Published: March 2017

Improved thermoelectric performance of BiCuSeO via increased bond covalency and carrier mobility.
Controllable preparation of phosphonium-based polymeric ionic liquids as highly selective nanocatalysts for the chemical conversion of CO2 with epoxides
Authors: Liu Ying , Cheng Weiguo , Zhang Yanqiang , Sun Jian , Zhang Suojiang
Published: March 2017

Phosphonium-based polymeric ionic liquids (PILs) have been prepared in a controlled way by using a microfluidic technique within an improved membrane microdevice.
Synthesis and properties enhancement of metal nanoclusters templated on a biological molecule/ionic liquids complex
Authors: Wang Wei , Peng Xiaolun , Xiong Huayu , Wen Wei , Bao Ting , Zhang Xiuhua , Wang Shengfu
Published: March 2017

Two biological template molecules and two short-chain imidazolium ionic liquids with amphipathy were selected to synthesize four different types of metal nanoclusters, which were templated on a biological molecule/imidazolium ionic liquids complex.
A study of diketopiperazines as electron-donor initiators in transition metal-free haloarene–arene coupling
Authors: Cumine Florimond , Zhou Shengze , Tuttle Tell , Murphy John A.
Published: March 2017

The electron-donating ability of enolates of N,N′-disubstituted diketopiperazines is strongly influenced by the nature of the substituents.
Preparation and characterization of novel alkali-resistant nanofiltration membranes with enhanced permeation and antifouling properties: the effects of functionalized graphene nanosheets
Authors: Xie Quanling , Zhang Shishen , Xiao Zongyuan , Hu Xiangfeng , Hong Zhuan , Yi Ruizao , Shao Wenyao , Wang Qiuquan
Published: March 2017

In this study, novel alkali-resistant NF membranes were developed by incorporating two kinds of functionalized graphene nanosheets into PES matrix. PES–SG demonstrated more great promise due to its superior permeability and antifouling performance.
Domino carbometalation/coupling reactions of N-arylpropiolamides: a novel and promising synthetic strategy toward stereocontrolled preparation of highly substituted 3-methyleneindolinones
Authors: Vessally E. , Hosseinzadeh-Khanmiri R. , Ghorbani-Kalhor E. , Es'haghi M. , Bekhradnia A.
Published: March 2017

3-Methyleneindolinone derivatives are important structural motifs found in many compounds of natural occurrence and pharmacological significance.
Long-term antibacterial protected cotton fabric coating by controlled release of chlorhexidine gluconate from halloysite nanotubes
Authors: Wu Yu , Yang Yongtao , Liu Haoyang , Yao Xihui , Leng Fan , Chen Yun , Tian Weiqun
Published: March 2017

An antibacterial HNTs/CG composite with controlled release was prepared, and used to coat cotton to obtain an antibacterial and biocompatible cotton fabric.
Powder metallurgically synthesized Cu12Sb4S13tetrahedrites: phase transition and high thermoelectricity
Authors: Sun Fu-Hua , Wu Chao-Feng , Li Zhiliang , Pan Yu , Asfandiyar Asfandiyar , Dong Jinfeng , Li Jing-Feng
Published: March 2017

A powder metallurgical process was used to synthesise Cu12Sb4S13−xcompounds as natural powders for use as high performance thermoelectric materials.
Ni/nitrogen-doped graphene nanotubes acted as a valuable tailor for remarkably enhanced hydrogen evolution performance of platinum-based catalysts
Authors: Bao Xiaobing , Wang Jing , Lian Xu , Jin Haiyan , Wang Shiping , Wang Yong
Published: March 2017

The electronic interactions between Pt and Ni@NGNTs tuned the electronic properties and greatly boosted catalytic performances of the anchored Pt NPs.
Potassium-chemical synthesis of 3D graphene from CO2and its excellent performance in HTM-free perovskite solar cells
Authors: Wei Wei , Hu Baoyun , Jin Fangming , Jing Zhenzi , Li Yuexiang , García Blanco Andres Alberto , Stacchiola Dario J. , Hu Yun Hang
Published: March 2017

The conversion of greenhouse gas CO2into novel materials is the most promising approach to solve greenhouse gas issues.
Experimental and theoretical insights into sustained water splitting with an electrodeposited nanoporous nickel hydroxide@nickel film as an electrocatalyst
Authors: Xing Zhicai , Gan Linfeng , Wang Jin , Yang Xiurong
Published: March 2017

Electrodeposited nanoporous Ni(OH)2@Ni film acts as a Janus electrocatalyst for the hydrogen evolution and oxygen evolution reaction, and overall water splitting, exhibiting superior activities and exceptional long-term stability. Theoretical calculations show that the synergistic electrocatalytic effects of Ni(OH)2 and Ni are responsible for the high activities.
Extracellular matrix powder from cultured cartilage-like tissue as cell carrier for cartilage repair
Authors: Teng Yingying , Li Xiupeng , Chen Yafang , Cai Hanxu , Cao Wanxu , Chen Xuening , Sun Yong , Liang Jie , Fan Yujiang , Zhang Xingdong
Published: March 2017

Efficiently cultivating cartilage decellularized matrix powder by a 3D culture method for cartilage repair in rabbit osteochondral defects.
Probing lattice vibration and surface electronic state in a layered (NH4)2V3O8 single crystal
Authors: Chen Haiping , Sun Zhongti , Wang Chengming , Li Xiuling , Zheng Xusheng , Zhang Youkui , He Qun , Wu Xiaojun , Song Li
Published: March 2017

Two-dimensional layered structure of a single crystal is regarded as an ideal feature for physical and chemical fundamental studies.
Giant UV photoresponse of a GaN nanowire photodetector through effective Pt nanoparticle coupling
Authors: Zhang Xinglai , Liu Qingyun , Liu Baodan , Yang Wenjin , Li Jing , Niu Pingjuan , Jiang Xin
Published: March 2017

A GaN NW UV photodetector with superior wavelength selectivity exhibits significant enhancement of photocurrent, responsivity, EQE and sensitivity after Pt NPs decoration due to the strong absorption and scattering of incident light and the improvement of interfacial charge separation.
Long-term load duration induces N-cadherin down-regulation and loss of cell phenotype of nucleus pulposus cells in a disc bioreactor culture
Authors: Li Pei , Zhang Ruijie , Wang Liyuan , Gan Yibo , Xu Yuan , Song Lei , Luo Lei , Zhao Chen , Zhang Chengmin , Ouyang Bin , Tu Bing , Zhou Qiang
Published: March 2017

Long-term exposure to a mechanical load causes degenerative changes in the disc nucleus pulposus (NP) tissue. A previous study demonstrated that N-cadherin (N-CDH)-mediated signalling can preserve the NP cell phenotype. However, N-CDH expression and the resulting phenotype alteration in NP cells under mechanical compression remain unclear. The present study investigated the effects of the compressive duration on N-CDH expression and on the phenotype of NP cells in an ex vivo disc organ culture. Porcine discs were organ cultured in a self-developed mechanically active bioreactor for 7 days. The discs were subjected to different dynamic compression durations (1 and 8 h at a magnitude of 0.4 MPa and frequency of 1.0 Hz) once per day. Discs that were not compressed were used as controls. The results showed that long-term compression duration (8 h) significantly down-regulated the expression of N-CDH and NP-specific molecule markers (Brachyury, Laminin, Glypican-3 and Keratin 19), attenuated Alcian Blue staining intensity, decreased glycosaminoglycan (GAG) and hydroxyproline (HYP) contents and decreased matrix macromolecule (aggrecan and collagen II) expression compared with the short-term compression duration (1 h). Taken together, these findings demonstrate that long-term load duration can induce N-CDH down-regulation, loss of normal cell phenotype and result in attenuation of NP-related matrix synthesis in NP cells.
Pathogenesis of white matter changes in cerebral small vessel diseases: beyond vessel-intrinsic mechanisms
Authors: Joutel Anne , Chabriat Hugues
Published: March 2017

Cerebral small vessel diseases (SVDs) are a leading cause of age and hypertension-related stroke and dementia. The salient features of SVDs visible on conventional brain magnetic resonance images include white matter hyperintensities (WMHs) on T2-weighted images, small infarcts, macrohemorrhages, dilated perivascular spaces, microbleeds and brain atrophy. Among these, WMHs are the most common and often the earliest brain tissue changes. Moreover, over the past two decades, large population- and patient-based studies have established the clinical importance of WMHs, notably with respect to cognitive and motor disturbances. Here, we seek to provide a new and critical look at the pathogenesis of SVD-associated white matter (WM) changes. We first review our current knowledge of WM biology in the healthy brain, and then consider the main clinical and pathological features of WM changes in SVDs. The most widely held view is that SVD-associated WM lesions are caused by chronic hypoperfusion, impaired cerebrovascular reactivity (CVR) or blood–brain barrier (BBB) leakage. Here, we assess the arguments for and against each of these mechanisms based on population, patient and experimental model studies, and further discuss other potential mechanisms. Specifically, building on two recent seminal studies that have uncovered an anatomical and functional relationship between oligodendrocyte progenitor cells and blood vessels, we elaborate on how small vessel changes might compromise myelin remodelling and cause WM degeneration. Finally, we propose new directions for future studies on this hot research topic.
Effect of temperature and radial force on the transmission performance of contactless power transfer for rotary ultrasonic grinding
Authors: Luan Yujia , Lin Bin , Yang Qiang , Duan Jiyue
Published: March 2017

Rotary transformer has gradually become used in rotary ultrasonic machining device for power transmission. Compared with contact power transmission, such as slip ring, the contactless power transfer system makes it possible to transmit power without friction, abrasion, vibration and heat. However, in rotary ultrasonic grinding, the varieties of temperature and mechanical load will greatly impact the transmission performance of the contactless energy transfer circuit. This study presents a simple mathematical model of four circuit compensation topologies, which is applicable for non‐ideal condition, and explores the transmission efficiency, output power, and voltage of compensation elements under different temperature and mechanical loads based on this model. The optimal compensation method for the rotary ultrasonic grinding is determined by comparison.
Analysis and simulation of a sliding mode controller for mechanical part of a doubly‐fed induction generator‐based wind turbine
Authors: Jafari Ahmad , Shahgholian Ghazanfar
Published: March 2017

In this study, a sliding mode controller (SMC) is designed to regulate rotor speed, and therefore generated power of a doubly‐fed induction generator‐based wind turbine. The designed controller is able to compensate for the uncertainty arising from non‐linear and un‐modelled dynamics, reject wind turbulence disturbance, and effectively keep the rotor speed and produced power close to a nominal value. Since the chattering phenomenon increases the control activities and excites unwanted high‐frequency dynamics of a system and even in some cases, causes system instability; therefore, a fixed boundary layer is used to avoid the chattering. The simulation results show the considerable superiority of the designed SMC in comparison with the conventional proportional–integral (PI) controller and the PI controller calculated through optimal control method. Improving dynamic characteristics, reducing the maximum amplitude of oscillations, and increasing the convergence speed of the states are achieved in this research.
Intelligent fault diagnosis approach with unsupervised feature learning by stacked denoising autoencoder
Authors: Xia Min , Li Teng , Liu Lizhi , Xu Lin , de Silva Clarence W.
Published: March 2017

Condition monitoring and fault diagnosis are important for maintaining the system performance and guaranteeing the operational safety. The traditional data‐driven approaches mostly incorporate well‐defined features and methodologies such as supervised artificial intelligence algorithms. Prior knowledge of possible features and a large quantity of labelled condition data are needed. Besides, many traditional approaches require rebuilding or a retraining of the original model to diagnosis new conditions. The present study proposes an intelligent fault diagnosis approach that uses a deep neural network (DNN) based on stacked denoising autoencoder. Representative features are learned by applying the denoising autoencoder to the unlabelled data in an unsupervised manner. A DNN is then constructed and fine‐tuned with just a few items of labelled data. The trained DNN achieves high performance in fault classification. Furthermore, new conditions can be correctly classified by simply fine‐tuning the trained DNN model using a small amount of labelled data under the new conditions. The effectiveness of the proposed approach is evaluated using a case study of fault diagnosis of a bearing unit. The results indicate that the proposed method can extract representative features from massive unlabelled data on the system condition and achieve high performance in fault diagnosis.
Time-resolved correlative optical microscopy of charge-carrier transport, recombination, and space-charge fields in CdTe heterostructures
Authors: Kuciauskas Darius , Myers Thomas H. , Barnes Teresa M. , Jensen Søren A. , Allende Motz Alyssa M.
Published: March 2017

From time- and spatially resolved optical measurements, we show that extended defects can have a large effect on the charge-carrier recombination in II–VI semiconductors. In CdTe double heterostructures grown by molecular beam epitaxy on the InSb (100)-orientation substrates, we characterized the extended defects and found that near stacking faults the space-charge field extends by 2–5 μm. Charge carriers drift (with the space-charge field strength of 730–1,360 V cm−1) and diffuse (with the mobility of 260 ± 30 cm2 V−1 s−1) toward the extended defects, where the minority-carrier lifetime is reduced from 560 ns to 0.25 ns. Therefore, the extended defects are nonradiative recombination sinks that affect areas significantly larger than the typical crystalline grains in II–VI solar cells. From the correlative time-resolved photoluminescence and second-harmonic generation microscopy data, we developed a band-diagram model that can be used to analyze the impact of extended defects on solar cells and other electronic devices.
Experimental demonstration of 55-fs spin canting in photoexcited iron nanoarrays
Authors: Ren Yuhang , Lai Wei , Cevher Zehra , Gong Yu , Zhang G. P.
Published: March 2017

As magnetic storage density approaches 1TB/in2, a grand challenge is looming as how to read/write such a huge amount of data within a reasonable time. The ultrafast optical manipulation of magnetization offers a solution, but little is known about the intrinsic speed limit of quantum spin switching. Here, we report that low-energy 50-fs laser pulses can induce spin canting in Fe nanoparticles within 55 fs, breaking the previous record by at least one order of magnitude. Both linearly and circularly polarized light can be used to tilt spins. In our model, the incident laser field first excites the orbital angular momentum, and through spin-orbit coupling, the spin cants out-of-plane and results in a distinctive diamond hysteresis loop. The spin canting time decreases with spin angular momentum. This spin canting is not limited to Fe nanoparticles and is also observed in Fe/Pt and Fe3O4 nanoparticles. Our results demonstrate the potential of magnetic nanostructures as a viable magnetic medium for high density and fast-switching magnetic storage devices.
Hidden hyperchaos and electronic circuit application in a 5D self-exciting homopolar disc dynamo
Authors: Wei Zhouchao , Moroz Irene , Sprott J. C. , Akgul Akif , Zhang Wei
Published: March 2017

We report on the finding of hidden hyperchaos in a 5D extension to a known 3D self-exciting homopolar disc dynamo. The hidden hyperchaos is identified through three positive Lyapunov exponents under the condition that the proposed model has just two stable equilibrium states in certain regions of parameter space. The new 5D hyperchaotic self-exciting homopolar disc dynamo has multiple attractors including point attractors, limit cycles, quasi-periodic dynamics, hidden chaos or hyperchaos, as well as coexisting attractors. We use numerical integrations to create the phase plane trajectories, produce bifurcation diagram, and compute Lyapunov exponents to verify the hidden attractors. Because no unstable equilibria exist in two parameter regions, the system has a multistability and six kinds of complex dynamic behaviors. To the best of our knowledge, this feature has not been previously reported in any other high-dimensional system. Moreover, the 5D hyperchaotic system has been simulated using a specially designed electronic circuit and viewed on an oscilloscope, thereby confirming the results of the numerical integrations. Both Matlab and the oscilloscope outputs produce similar phase portraits. Such implementations in real time represent a new type of hidden attractor with important consequences for engineering applications.
Are continuum predictions of clustering chaotic?
Authors: Fullmer William D. , Hrenya Christine M.
Published: March 2017

Gas-solid multiphase flows are prone to develop an instability known as clustering. Two-fluid models, which treat the particulate phase as a continuum, are known to reproduce the qualitative features of this instability, producing highly-dynamic, spatiotemporal patterns. However, it is unknown whether such simulations are truly aperiodic or a type of complex periodic behavior. By showing that the system possesses a sensitive dependence on initial conditions and a positive largest Lyapunov exponent, λ1≈1/τ, we provide a tentative answer: continuum predictions of clustering are chaotic. We further demonstrate that the chaotic behavior is dimensionally dependent, a conclusion which unifies previous results and strongly suggests that the chaotic behavior is not a direct consequence of the fundamental kinematic instability, but requires a secondary (inherently multidimensional) instability.
Smooth information flow in temperature climate network reflects mass transport
Authors: Hlinka Jaroslav , Jajcay Nikola , Hartman David , Paluš Milan
Published: March 2017

A directed climate network is constructed by Granger causality analysis of air temperature time series from a regular grid covering the whole Earth. Using winner-takes-all network thresholding approach, a structure of a smooth information flow is revealed, hidden to previous studies. The relevance of this observation is confirmed by comparison with the air mass transfer defined by the wind field. Their close relation illustrates that although the information transferred due to the causal influence is not a physical quantity, the information transfer is tied to the transfer of mass and energy.
Symmetry breaking of ion temperature gradient mode structure: From local to global analysis
Authors: Lu Z. X. , Fable E. , Hornsby W. A. , Angioni C. , Bottino A. , Lauber Ph. , Zonca F.
Published: March 2017

The 2D mode structure symmetry breaking of the ion temperature gradient mode is studied analytically and numerically based on the mixed initial-value-eigenvalue approach, the Gyrokinetic PIC code ORB5 and the gyrokinetic Eulerian code GKW. The radial propagation and amplitude variation, in terms of the real and imaginary parts of the generalized “tilting parameter” θk, are treated in the framework of the Mode Structure Decomposition approach. The radial symmetry breaking is shown to be intimately coupled to the parallel symmetry breaking. In particular, Im{θk} can lead to the increase in the local growth rate and the absolute value of the real frequency, as well as to parallel symmetry breaking. The complex θk can be measured in global simulations and accounted for in local simulations. This provides a way to include global effects related to the mode radial propagation and the intensity gradient in local descriptions and can be important for the study of momentum transport.
Switching field reduction of a perpendicular magnetic nanodot in a microwave magnetic field emitted from a spin-torque oscillator
Authors: Suto Hirofumi , Kanao Taro , Nagasawa Tazumi , Kudo Kiwamu , Mizushima Koichi , Sato Rie
Published: March 2017

We demonstrate microwave-assisted magnetization switching of a perpendicular magnetic nanodot in a microwave stray field from a spin-torque oscillator (STO). The switching field decreases when the STO is operated by applying a current. The switching field reduction is almost the same as that in a microwave magnetic field generated by a signal generator despite the fluctuations of the STO oscillation. The switching field distribution, however, is broader when the STO is used. We also examine the magnetization switching process in the nanosecond region by applying a nanosecond-order pulse current to the STO and measuring the STO signal waveform. The onset of the STO oscillation and subsequent assisted switching occur within a few nanoseconds.
Accurate barrier heights using diffusion Monte Carlo
Authors: Krongchon Kittithat , Busemeyer Brian , Wagner Lucas K.
Published: March 2017

Fixed node diffusion Monte Carlo (DMC) has been performed on a test set of forward and reverse barrier heights for 19 non-hydrogen-transfer reactions, and the nodal error has been assessed. The DMC results are robust to changes in the nodal surface, as assessed by using different mean-field techniques to generate single determinant wave functions. Using these single determinant nodal surfaces, DMC results in errors of 1.5(1) kcal/mol on barrier heights. Using the large data set of DMC energies, we attempted to find good descriptors of the fixed node error. It does not correlate with a number of descriptors including change in density but does show some correlation with the gap between the highest occupied and lowest unoccupied orbital energies in the mean-field calculation.
Short-wave infrared (λ = 3 μm) intersubband polaritons in the GaN/AlN system
Authors: Laurent T. , Manceau J.-M. , Monroy E. , Lim C. B. , Rennesson S. , Semond F. , Julien F. H. , Colombelli R.
Published: March 2017

We demonstrate intersubband polaritons in the short-infrared wavelength range (λ < 3 μm) relying on the GaN/AlN semiconductor system. The demonstration is given for an intersubband transition centered at λ = 3.07 μm (E = 403 meV). The polaritonic dispersion is measured at room temperature: a Rabi energy of 53 meV (i.e., a minimum splitting of 106 meV), which represents 13.1% of the bare transition, is demonstrated. A metal-insulator-metal resonator architecture is employed, which proves to be efficient even at these short wavelengths.