bluuebunny/crossref_metadata_2025 huggingface dataset:
Capsular‐defective Porphyromonas gingivalis mutant strains induce less alveolar bone resorption than W50 wild‐type strain due to a decreased Th1/Th17 immune response and less osteoclast activity
Authors: Monasterio Gustavo , Fernández Baltasar , Castillo Francisca , Rojas Carolina , Cafferata Emilio A. , Rojas Leticia , Alvarez Carla , Fernández Alejandra , Hernández Marcela , Bravo Denisse , Vernal Rolando
Published: November 2018

Background

Encapsulation of Porphyromonas gingivalis has been demonstrated as responsible of several host immunological changes, which have been associated with the pathogenesis of periodontitis. Using a murine model of periodontitis and two isogenic non‐capsulated mutants of P. gingivalis, this study aimed to analyze whether P. gingivalis encapsulation induces more severe alveolar bone resorption, and whether this bone loss is associated with a T‐helper (Th)1 and Th17‐pattern of immune response.

Methods

Experimental periodontal infections were generated by oral inoculation with the encapsulated W50 wild‐type strain or isogenic non‐encapsulated ΔPG0116‐PG0120 (GPA) and ΔPG0109‐PG0118 (GPC) mutants of P. gingivalis. Periodontal infections induced with the encapsulated HG184 or non‐encapsulated ATCC 33277 strains of P. gingivalis were used as controls. Alveolar bone resorption was analyzed using microcomputed tomography and scanning electron microscopy. The expression levels of Th1, Th2, Th17, or T regulatory‐associated cytokines and RANKL, as well as the periodontal bacterial load, were quantified by quantitative polymerase chain reaction. The detection of Th1 and Th17 lymphocytes was analyzed by flow cytometry.

Results

In the periodontal lesions, both capsular‐defective knockout mutant strains of P. gingivalis induced less alveolar bone resorption than the encapsulated W50 wild‐type strain. This decreased bone loss was associated with a dismissed RANKL expression, decreased Th1‐ and Th17‐type of cytokine expression, reduced Th1 and Th17 lymphocyte detection, and low osteoclast finding.

Conclusion

These data demonstrate that encapsulation of P. gingivalis plays a key role in the alveolar bone resorption induced during periodontitis, and this bone loss is associated with a Th1‐ and Th17‐pattern of immune response triggered in the periodontal lesions.
Cross‐sectional analysis of risk factors for subclinical periodontitis; active matrix metalloproteinase‐8 as a potential indicator in initial periodontitis in adolescents
Authors: Heikkinen Anna Maria , Räisänen Ismo T. , Tervahartiala Taina , Sorsa Timo
Published: November 2018

Background

The aim of this study was to investigate how different patient‐related risk indicators might be associated with the odds of developing subclinical periodontitis in adolescents.

Methods

This cross‐sectional study included 252 Finnish individuals aged 15 to 16 years, of whom 141 were boys and 111 girls. A specially trained dentist performed clinical examinations: measurements included periodontal indexes (bleeding on probing, visible plaque index, root calculus, and probing depth, smoking by pack‐years, periodontal bacteria (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola) and the potential salivary periodontal biomarkers (active matrix metalloproteinase‐8 [aMMP‐8], polymorphonuclear leukocyte elastase [PMN elastase], and total protein, albumin, immunoglobulin A, immunoglobulin G, and immunoglobulin M). Results were analyzed by ordinal logistic regression, one‐way analysis of variance, Fisher exact test, and Kruskal‒Wallis H test.

Results

The main finding of this study was that subclinical periodontitis in adolescents was statistically significantly associated with elevated salivary aMMP‐8 but not with PMN elastase. Also, adolescents with subclinical periodontitis had statistically significantly higher levels of bleeding on probing, root calculus, and dental plaque than adolescents without subclinical periodontitis.

Conclusions

We suggest that the main risk factor for subclinical periodontitis in adolescents is the partly calcified, dysbiotic bacterial biofilm, which interacts with the immune defenses of the host; this leads to gingival inflammation and eventually to deepening periodontal pockets. This proinflammatory subclinical periodontitis stage, which represents stage I periodontitis in the new classification, is reflected as elevated salivary aMMP‐8 levels in oral fluids.
Accurate wavenumber measurements for the S0(0), S0(1), and S0(2) pure rotational Raman lines of D2
Authors: Martínez Raúl Z. , Bermejo Dionisio , Wcisło Piotr , Thibault Franck
Published: November 2018

We present accurate measurements for the wavenumbers of the S0(0), S0(1), and S0(2) pure rotational Raman lines in D2. Our measurements improve the accuracy of the previously available experimental data by an order of magnitude. They also show complete agreement with the state‐of‐the‐art ab initio calculations of the D2 rotational splitting, which include both relativistic and Quantum electrodynamics (QED) corrections.
Tumor cell seeding in the biopsy tract and its clinical significance in osteosarcomas
Authors: Turkoz Kemal H. , Erol Bulent , Seven Ipek E.
Published: November 2018

Background and objectives

The reasons behind the removal of the biopsy tract in osteosarcomas are not well known, and studies about tumor seeding in the biopsy tract have generated conflicting results. This study is designed to evaluate the presence and possible clinical significance of tumor cell seeding in the biopsy tract of osteosarcomas.

Methods

We prospectively evaluated 55 cases of osteosarcomas for tumor cell seeding and other clinical and pathologic prognostic parameters.

Results

Eleven cases (20%) involved microscopic tumor foci in the biopsy tract. The higher local recurrence rates (P = 0.005) and worse recurrence‐free survivals (
P = 0.009) were observed in patients with tumor cell foci in the biopsy tract. Mitotic rate, tumor cell pleomorphism, and matrix production in main tumor foci were higher in cases with tumor seeding (
P = 0.047,
P = 0.012, and
P = 0.005, respectively)

Conclusions

Tumor seeding in the biopsy tract is a fact in osteosarcomas. The higher local recurrence rates are more likely to occur in cases with tumor seeding.
Management of locoregional recurrence after radical resection of a primary nonmetastatic retroperitoneal soft tissue sarcoma: The Gustave Roussy experience
Authors: Honoré Charles , Faron Matthieu , Mir Olivier , Haddag‐Miliani Leila , Dumont Sarah , Terrier Philippe , LePéchoux Cecile , Botticella Angela , Adam Julien , Le Cesne Axel
Published: November 2018

Background

Despite surgery, many patients experience locoregional recurrence (LR), the optimum treatment of which is still debated.

Methods

All 297 consecutive patients operated for a nonmetastatic primary retroperitoneal soft tissue sarcoma (RPS) between 1994 and 2017 were retrospectively analyzed to report our experience in treating LR.

Results

After a median follow‐up of 97 months, 55 patients (19%) developed LR. The first site of recurrence was locoregional in 100% with associated peritoneal metastases in 45% and distant metastases in 5%. After LR treatment, the 1‐, 3‐, and 5‐year overall survival (OS) rates were 71%, 46%, and 33%. Low tumor grade, disease‐free interval above 24 months, exclusive LR, and well‐differentiated liposarcoma were predictive of better OS. The treatment strategy (best supportive care, chemotherapy radiotherapy, and/or surgery) was not statistically significant. Fourteen patients underwent initial surveillance (strategic delay) for low‐grade LR and eventually required treatment in 86% after a median delay of 20 months during which no patient developed distant metastases.

Conclusions

The management of LR in RPS is complex. An initial surveillance may not alter survival in asymptomatic low‐grade and slow‐growing LR. An LR decision scheme is proposed.
Guidelines for tuning the macropore structure of monolithic columns for high‐performance liquid chromatography
Authors: Dores‐Sousa José Luís , Fernández‐Pumarega Alejandro , De Vos Jelle , Lämmerhofer Michael , Desmet Gert , Eeltink Sebastiaan
Published: November 2018

The ability to control the external porosity and to tune the dimensions of the macropore size on multiple length scales provides the possibility of tailoring the monolithic support structure towards separation performance. This paper discusses the properties of conventional polymer–monolithic stationary phases and its limitations regarding the effects of morphology on kinetic performance. Furthermore, guidelines to improve the macropore structure are discussed. The optimal monolithic macropore structure is characterized by high external porosity (while maintaining ultra‐high‐pressure stability), high structure homogeneity, polymer globule clusters in the submicron range, and macropores with a diameter tuned toward speed (small diameter in the 100–500 nm range using short beds) or efficiency (larger macropores in the range of 500 nm–1 μm allowing the use of longer column formats). Finally, promising approaches to control the morphology are discussed.
Posttraumatic Stress Disorder in Patients With Borderline Personality Disorder: Treatment Outcomes and Mediators
Authors: Barnicot Kirsten , Crawford Mike
Published: November 2018

Posttraumatic stress disorder (PTSD) is highly comorbid with personality disorder (PD). We evaluated whether comorbid PTSD has a negative effect on patients’ ability to benefit from evidence‐based psychological treatments for PD and tested potential mediators of any effect. The effect of PTSD on self‐harm and borderline PD symptoms was evaluated in 90 patients with borderline PD who were receiving dialectical behavior therapy or mentalization‐based therapy. Self‐report and interview measures were administered every 3 months over a 12‐month period. Three‐quarters of participants met criteria for PTSD. In the 12 months after beginning treatment, participants with PTSD did not engage in self‐harm more often or present with more severe borderline PD symptoms. However, a higher level of PTSD symptom severity at baseline was associated with more frequent self‐harm during follow‐up, incidence rate ratio = 1.03, 95% CI [1.01, 1.06], p = .005. Participants whose PTSD did not improve or worsened were more likely to still self‐harm, odds ratio (OR) = 0.91, 95 % CI [0.85, 0.97], p = .004, and report more severe borderline PD symptoms, b = 0.53, 95% CI [0.34, 0.73], p < .001, at the end of 12 months. The negative effects of PTSD symptoms remained significant after adjusting for potential confounders and were partially mediated by high ongoing levels of emotional dysregulation, indirect effect b = 0.32, 95% CI [0.19, 0.50]. These findings identify subgroups at risk of poorer outcomes from evidence‐based psychological treatments for PD and support the idea that treating PTSD may improve outcomes.
Ignoring heat inertia impairs accuracy of determination of activation energy in thermal analysis
Authors: Šesták Jaroslav
Published: November 2018

This paper critically analyzes the traditional method of kinetic determination of activation energy by sectioning the recorded differential thermal analysis peak area. This procedure is incorrect because it misses the impact of thermal inertia, which changes the shape of the peak's base line from straight to s‐shape. This effect has been known since the Newton cooling law, but the resulting errors persist to be interwoven into all the kinetic methods based on nonisothermal thermoanalytical measurements. Relating to calorimetry, it is necessary here because heat inertia has become a standard part of heat determination via using the Tian historical equation. The role and impact of heat inertia is discussed and analyzed in detail.
Identifying (our) donors: Toward a social psychological understanding of charity selection in Australia
Authors: Chapman Cassandra M. , Louis Winnifred R. , Masser Barbara M.
Published: November 2018

Gender, age, religiosity, and political orientation are often associated with a propensity to give to charity. However, these broad associations mask inconsistencies that are not yet understood. Just as identity plays an important role in shaping consumer choices generally, donors’ identities could explain diverging associations between demographic social categories and the types of charities supported. Two studies, with confirmed workplace giving donors (N = 675) and a community sample of self‐reported donors (N = 376) in Australia, provide evidence that associations significantly vary across categories of charity. Specifically, older donors are more likely to support religious and health charities; religious donors are more likely to support religious, welfare, and international organizations, but less likely to support animal charities; and politically conservative donors are less likely than liberal donors to donate to international organizations. The findings are interpreted through the lens of identity, with a focus on how group priorities and relevant norms may affect charity selection. The results have implications for nonprofit marketing practice, including targeting, channel selection, and framing of fundraising appeals.
Quantitative insights from online qualitative data: An example from the health care sector
Authors: Pitt Christine , Mulvey Michael , Kietzmann Jan
Published: November 2018

Among the deluge of online data generated by users in the form of text on social media sites, health care reviews are among the most common, and potentially, the most insightful. Patients review and comment on the experiences with procedures as varied as hysterectomies, colonoscopies, and chemotherapy. In their attempts to reduce the uncertainty associated with medical treatments, many patients nowadays also turn to social media, where they rely on the experiences articulated by other patients. In this study, IBM Watson is used to examine how knee replacement patients talk about their emotions and express sentiment through their comments online. Then, a latent class cluster modeling procedure is used to segment these patients into distinct groups, according to their emotions (anger, disgust, fear, happiness, sadness, and surprise), sentiment, and their overall satisfaction with knee replacement surgery. The findings show how qualitative online data can be transformed into quantitative insights regarding underlying market segments, which could then be targeted through different strategies by both marketers and health care practitioners.
Some remarks on short‐time Fourier integral operators and classes of rapidly decaying functions
Authors: Al‐Omari Shrideh K. Q.
Published: November 2018

In this article, we extend the space of rapidly decaying functions to a space of rapidly decaying Boehmians. We provide convolution products, convolution theorems and generate their associated spaces of Boehmian. Then, we define the short‐time Fourier integral operator on the Boehmian spaces. Moreover, we show that the short‐time Fourier integral operator of the Boehmian is a sequentially continuous mapping that preserves certain desired properties. An inversion formula and some injections have also been obtained.
Numerical determination of the effective permeability coefficient of soil–rock mixtures using the numerical manifold method
Authors: Chen Tao , Yang Yongtao , Zheng Hong , Wu Zhijun
Published: November 2018

The present study extends the numerical manifold method to investigate the effective permeability coefficient (keff) of soil–rock mixtures. The influence of rock content, rock size, rock shape, and rock blocks' major axis direction on keff is studied. The results show the following: (1) keff decreases as the rock content increases; (2) the influence of rock size on keff can be neglected if other parameters are fixed; (3) the values of keff are nearly the same if rock blocks are in circular or regular hexagon shapes; and (4) the major axis direction of rock blocks has some influence on keff.
A novel efficient mixed formulation for strain‐gradient models
Authors: Papanicolopulos Stefanos‐Aldo , Gulib Fahad , Marinelli Aikaterini
Published: November 2018

Various finite elements based on mixed formulations have been proposed for the solution of boundary value problems involving strain‐gradient models. The relevant literature, however, does not provide details on some important theoretical aspects of these elements. In this work, we first present the existing elements within a novel, single mathematical framework, identifying some theoretical issues common to all of them that affect their robustness and numerical efficiency. We then proceed to develop a new family of mixed elements that addresses these issues while being simpler and computationally cheaper. The behavior of the new elements is further demonstrated through two numerical examples.
Permittivity mapping in the VLF–LF range using a multi‐frequency EMI device: first tests in archaeological prospection
Authors: Simon Fançois‐Xavier , Tabbagh Alain , Donati Jamieson C. , Sarris Apostolos
Published: November 2018

In the early years of near‐surface geophysical applications, measurements obtained using electromagnetic induction (Slingram or dipole–dipole) instruments were first interpreted in terms of electrical conductivity. Afterwards, studies began considering the importance of magnetic susceptibility. Until now, however, no attention has been paid to possible responses in dielectric permittivity. After reviewing the current state of knowledge regarding the expected theoretical responses in the very low frequency to low frequency (VLF‐LF) range (3–300 kHz) and the value range of this property for soils, we propose the use of multi‐frequency instruments to define a process allowing for the determination of the apparent conductivity and permittivity in the higher part of the frequency range above 20 kHz. We test this process through a series of experiments at archaeological sites in Greece using the GEM‐2 (Geophex Ltd) instrument. In our experiments, the soil permittivity values fall between several hundredths and several thousandths. The results indicate lateral variations different from the other properties with a significant influence of the stone content and of the ionic strength, while a decrease with frequency may also provide further information on soil dielectric behaviours.
Robust H∞fuzzy control design for dithered nonlinear large‐scale systems with multiple time delays
Authors: Hsiao Feng‐Hsiag
Published: November 2018

A novel approach is proposed in this study to stabilize nonlinear multiple time‐delay (NMTD) large‐scale systems via a composite of fuzzy controllers and dithers. Moreover, a delay‐dependent stability criterion is derived from Lyapunov's direct method. According to this criterion and the decentralized control scheme, a set of model‐based fuzzy controllers is synthesized to stabilize the NMTD large‐scale system and the H∞ control performance is achieved at the same time. If the designed fuzzy controllers cannot stabilize the NMTD large‐scale system, a set of dithers (as the auxiliaries of fuzzy controllers) is simultaneously introduced to stabilize the NMTD large‐scale system. Finally, a numerical example with simulations is provided to illustrate the concepts discussed throughout this paper.
Axial p‐n junction design and characterization for InP nanowire array solar cells
Authors: Gao Qian , Li Ziyuan , Li Li , Vora Kaushal , Li Zhe , Alabadla Ahmed , Wang Fan , Guo Yanan , Peng Kun , Wenas Yesaya C. , Mokkapati Sudha , Karouta Fouad , Tan Hark Hoe , Jagadish Chennupati , Fu Lan
Published: November 2018

In this work, InP nanowire (NW) array solar cells with different axial p‐i‐n junction designs were investigated. The optical properties of the different NW structures were characterized through a series of microphotoluminescence measurements to extract important material parameters such as minority carrier lifetimes and internal quantum efficiencies. A glancing angle sputtering deposition technique has been developed to enable a direct visualization of the p‐n junctions in the vertical array of InP NW solar cells (NWSCs) using electron beam‐induced current (EBIC) technique. Based on EBIC and electrical simulation, it is found that the background doping in NWSC significantly affects the junction position. By modifying the junction design, the width and position of the p‐n junction can be varied effectively. By employing a p‐p−‐n structure, a high junction position (>1 μm from the substrate) and wide depletion width have been achieved as confirmed by EBIC measurement. Moreover, the NW growth substrate does not show any influence on the device behavior due to the fully decoupled junction position, indicating a promising structural design for future development of high‐performance, low‐cost flexible NW devices.
Designing a hybrid thin‐film/wafer silicon triple photovoltaic junction for solar water splitting
Authors: Perez‐Rodriguez Paula , Vijselaar Wouter , Huskens Jurriaan , Stam Machiel , Falkenberg Michael , Zeman Miro , Smith Wilson , Smets Arno H.M.
Published: November 2018

Solar fuels are a promising way to store solar energy seasonally. This paper proposes an earth‐abundant heterostructure to split water using a photovoltaic‐electrochemical device (PV‐EC). The heterostructure is based on a hybrid architecture of a thin‐film (TF) silicon tandem on top of a c‐Si wafer (W) heterojunction solar cell (a‐Si:H (TF)/nc‐Si:H (TF)/c‐Si(W)) The multijunction approach allows to reach enough photovoltage for water splitting, while maximizing the spectrum utilization. However, this unique approach also poses challenges, including the design of effective tunneling recombination junctions (TRJ) and the light management of the cell. Regarding the TRJs, the solar cell performance is improved by increasing the n‐layer doping of the middle cell. The light management can be improved by using hydrogenated indium oxide (IOH) as transparent conductive oxide (TCO). Finally, other light management techniques such as substrate texturing or absorber bandgap engineering were applied to enhance the current density. A correlation was observed between improvements in light management by conventional surface texturing and a reduced nc‐Si:H absorber material quality. The final cell developed in this work is a flat structure, using a top absorber layer consisting of a high bandgap a‐Si:H. This triple junction cell achieved a PV efficiency of 10.57%, with a fill factor of 0.60, an open‐circuit voltage of 2.03 V and a short‐circuit current density of 8.65 mA/cm2. When this cell was connected to an IrOx/Pt electrolyser, a stable solar‐to‐hydrogen (STH) efficiency of 8.3% was achieved and maintained for 10 hours.
A structured Solar System satellite relay constellation network topology design for Earth‐Mars deep space communications
Authors: Wan Peng , Zhan Yafeng
Published: November 2018

The deep space exploration missions require high quality of communication performance between the Earth stations and various deep space explorers, such as Mars orbiters and rovers. Due to the difficulties on improving the point‐to‐point physical wireless link capacity, it is necessary to study the relay network communications under the structured idea. In this paper, the structured Solar System satellite relay constellation network is proposed for Earth‐Mars deep space communications, including the mission background, mathematic model, topology design, and performance analysis. The satellite relay constellation could be modelled as a 2‐dimensional structure with multiple concentric circle loops and multiple relate satellites on each loop. With the different optimal objectives as shortest path, minimum hops and minimum nodes required under the constraint threshold distance for each hop, both the Monte Carlo method and modified Shortest Path First algorithms are studied to work out the optimal network topology designs. Simulation results show that, our network topology design could satisfy the requirements on continuous dual‐directional end‐to‐end communications between the Earth and Mars over the whole mission life period and guarantee the performance of end‐to‐end multihop links above the lowest boundary.
Early childhood science interest development: Variation in interest patterns and parent–child interactions among low‐income families
Authors: Pattison Scott A. , Dierking Lynn D.
Published: November 2018

Fostering interest in science is critical for broadening engagement with science topics, careers, and hobbies. Research suggests that these interests begin to form as early as preschool and have long‐term implications for participation and learning. However, scholars have only speculated on the processes that shape interest development at this age, when children’s exposure to science primarily occurs during family‐based learning experiences. Moving beyond speculation, we conducted a qualitative study with seven low‐income mothers and their four‐year‐old daughters from Head Start to (a) develop a descriptive understanding of science‐related interest development for preschool children from traditionally underserved communities and (b) identify differences across families that might explain the variation in children’s interests. The study was conducted over 5 months and included two in‐depth interviews and four videotaped sessions in which families engaged in science‐related activities. Interviews suggested that children’s science‐related interests sparked by the sessions fell along a continuum, fromfocusedinterests specific to the materials provided during the sessions tobroadinterests extending to more general topics and activity types. We also found important variation across families related to mothers’ expression of affect, their involvement and leadership styles, and their approach to re‐engaging children when they lost interest or changed focus.
An Efficient Protocol for the Synthesis of 1, 5‐ disubstituted Tetrazole Derivatives via a TMS‐N3 Based Ugi Reaction and their Anti‐cancer Activity
Authors: Gohel Jyoti N. , Lunagariya Kaushikkumar S. , Kapadiya Khushal M. , Khunt Ranjan C.
Published: November 2018

In current research scenario, an efficient synthesis has been developed for novel tetrazole scaffolds by single step multicomponent reaction. One of the most promising pathways is Ugi multi‐component process for the coupling of four different components in a single reaction step and isolate lead molecule which may serve better life to the society. The syntheses of tetrazoles were undertaken by the Ugi‐Multi Component approach with the condensation of aromatic aldehyde containing active pharmacophore, various aryl amines, isocyanide (cyclohexyl isocyanide) and TMS‐N3 under catalyst free reaction condition at room temperature. The structural conformation were carried out by most acceptable spectroscopic technique i.e. MS, IR, NMR and single crystal study (XRD) and potency of compounds (4a to 4h) were checked at NIH (National Institute of Health) use 60 different cell‐lines with respect to nine cancer panels among which compounds 4a and 4b have been found to be more potent against different cell lines.
Approaching Green BPM characterisation
Authors: Hernández González Anaisa , Calero Coral , Pérez Parra Dianelys , Mancebo Javier
Published: November 2018

Sustainable development is a type of development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Sustainability has recently become more and more important for businesses. This has led to what is known as Green BPM (Green business process management), in which sustainability is considered to be a business objective. The objective of this work was to carry out a systematic literature review in order to evaluate how the subject of Green BPM has evolved and how the term “Green BPM” has been conceptualised so as to propose a new definition compiled from those previously formulated; identify the impact of the incorporation of Green aspects into the BPM life cycle stages; and discover the impact of Green BPM research efforts by means of the PDCA (plan‐do‐check‐act) model, thus identifying (1) the goals that have been proposed when Green initiatives are carried out in BPM, (2) the context in which this has been applied, and (3) the performance indicators considered. Finally, we propose a new characteristic, Process Greenability, together with its subcharacteristics, in addition to identifying the relationship between these subcharacteristics and the indicators identified to make them measurable.
Controlled Leaching Derived Synthesis of Atomically Dispersed/Clustered Gold on Mesoporous Cobalt Oxide for Enhanced Oxygen Evolution Reaction Activity
Authors: Youk Sol , Hwang Jongkook , Lee Seonggyu , Kim Min Su , Lee Jinwoo
Published: November 2018

The water splitting for hydrogen energy is largely constrained by sluggish anodic oxygen evolution reaction (OER). Cobalt oxide, one of the most promising non‐noble metal catalysts for OER, can exhibit highly enhanced catalytic OER activity when deposited on gold substrates. However, it still remains challenging to develop efficient Au/Co3O4 catalysts that can maximize the catalytic activity with the minimum use of gold. Here is reported a simple leaching derived synthesis of atomically dispersed/clustered gold on mesoporous cobalt oxides as highly efficient catalysts for OER. With greatly lowered gold contents <1 wt%, the catalyst shows twice as much current density and Au normalized activity than mesoporous cobalt oxide at 400 mV overpotential. The present work provides a simple synthesis route toward atomically dispersed/clustered gold supported catalysts, which can be extended to the development of a wide variety of efficient nanocatalysts that can be designed for specific applications.
Wind turbine gearbox failure and remaining useful life prediction using machine learning techniques
Authors: Carroll James , Koukoura Sofia , McDonald Alasdair , Charalambous Anastasis , Weiss Stephan , McArthur Stephen
Published: November 2018

This research investigates the prediction of failure and remaining useful life (RUL) of gearboxes for modern multi‐megawatt wind turbines. Failure and RUL are predicted through the use of machine learning techniques and large amounts of labelled wind turbine supervisory control and data acquisition (SCADA) and vibration data. The novelty of this work stems from unprecedented access to one of the world's largest wind turbine operational and reliability databases, containing thousands of turbine gearbox failure examples and complete SCADA and vibration data in the build up to those failures. Through access to that data, this paper is unique in having enough failure examples and data to draw the conclusions detailed in the remainder of this abstract.

This paper shows that artificial neural networks provide the most accurate failure and RUL prediction out of three machine learning techniques trialled. This work also demonstrates that SCADA data can be used to predict failure up to a month before it occurs, and high frequency vibration data can be used to extend that accurate prediction capability to 5 to 6 months before failure. This paper demonstrates that two class neural networks can correctly predict gearbox failures between 72.5% and 75% of the time depending on the failure mode when trained with SCADA data and 100% of the time when trained with vibration data. Data trends in the build up to failure and weighting of the SCADA data inputs are also provided. Lastly, this work shows how multi‐class neural networks demonstrate more potential in predicting gearbox failure when trained with vibration data as opposed to training with SCADA data.
Rare Earth Metal PolytelluridesRETe1.8(RE= Gd, Tb, Dy) – Directed Synthesis, Crystal and Electronic Structures, and Bonding Features
Authors: Poddig Hagen , Donath Tom , Gebauer Paul , Finzel Kati , Kohout Miroslav , Wu Yuandong , Schmidt Peer , Doert Thomas
Published: November 2018

Single crystals of the polytelluridesRETe1.8of gadolinium, terbium, and dysprosium were prepared by chemical vapor transport and alkali metal halide flux reactions. To determine proper synthesis conditions for the desired target composition, the binary phase diagram Gd‐Te was evaluated by CalPhaD methods. The compounds are isostructural to SmTe1.8and crystallize in space groupP4/n(no. 85) with lattice parameters ofa= 966.10(4), 960.00(3), and 957.33(2) pm andc= 1794.15(10), 1785.77(6), and 1779.38(5) pm for GdTe1.8, TbTe1.8and DyTe1.8, respectively. The structures consist of puckered [RETe] double slabs and planar telluride layers composed of Te2dumbbells and linear Te3units in accordance with ELI‐D based bonding analyses. The latter can be understood as a Te34–anion. GdTe1.8is a semiconductor with a bandgap of 0.19 eV/0.17 eV (experimental/calculated). Magnetization data confirm trivalentREions and indicate antiferromagnetic order atTN= 12 K for TbTe1.8andTN= 9.8 K for DyTe1.8, whereas GdTe1.8remains paramagnetic down to 2 K.
Two New MOFs Based on Cu2 Paddlewheel Units and Biphenyltetracarboxylate Ligands with a Different Degree of Fluorination
Authors: Stastny Carina , Ruschewitz Uwe
Published: November 2018

Two new MOFs (metal‐organic frameworks), namely 3∞[Cu2(H2O)2(L)]·3DMF·H2O [L = 4‐fluoro‐biphenyl‐3,3′,5,5′‐tetracarboxylate (4‐mF‐BPTC4–) and 4,4′‐difluoro‐biphenyl‐3,3′,5,5′‐tetracarboxylate (4,4′‐dF‐BPTC4–)] termed UoC‐1(1F) and UoC‐1(2F) (UoC ≡ University of Cologne), were synthesized by solvothermal reactions in DMF. The crystal structure of UoC‐1(1F) was solved and refined from X‐ray single crystal data (Imma, Z = 4). The X‐ray powder diffraction data of UoC‐1(2F) confirmed that both MOFs are isostructural. In their crystal structures each of the four carboxylate groups of the BPTC4– linker is involved in a Cu2 paddlewheel unit leading to a 3D structure with high porosity, which was confirmed by N2 gas sorption measurements revealing specific surface areas of SBET = 1256 m2·g–1 [UoC‐1(1F)] and 1162 m2·g–1 [UoC‐1(2F)] after activation at 120 °C for 72 h. Higher activation temperatures lead to a decomposition of the framework and significantly decreased specific surface areas.
Towards exotic matter and discrete non-abelian symmetries in F-theory
Authors: Cvetič Mirjam , Heckman Jonathan J. , Lin Ling
Published: November 2018

Abstract

We present a prescription in F-theory for realizing matter in “exotic” representations of product gauge groups. For 6D vacua, bifundamental hypermultiplets are engineered by starting at a singular point in moduli space which includes 6D superconformal field theories coupled to gravity. A deformation in Higgs branch moduli space takes us to a weakly coupled gauge theory description. In the corresponding elliptically fibered Calabi-Yau threefold, the minimal Weierstrass model parameters (f, g, Δ) vanish at collisions of the discriminant at least to order (4, 6, 12), but with sufficiently high order of tangency to ensure the existence of T-brane deformations to a weakly coupled gauge theory with exotic bifundamentals. We present explicit examples including bifundamental hypermultiplets of

$$ {\mathfrak{e}}_7\times \mathfrak{s}{\mathfrak{u}}_2 $$

e
7

×
s

u
2

and

$$ {\mathfrak{e}}_6\times \mathfrak{s}{\mathfrak{u}}_3 $$

e
6

×
s

u
3

, each of which have dual heterotic orbifold descriptions. Geometrically, these matter fields are delocalized across multiple points of an F-theory geometry. Symmetry breaking with such representations can be used to produce high dimension representations of simple gauge groups such as the four-index symmetric representation of

$$ \mathfrak{s}{\mathfrak{u}}_2 $$

s

u
2

and the three-index symmetric representation of

$$ \mathfrak{s}{\mathfrak{u}}_3 $$

s

u
3

, and after further higgsing can yield discrete non-abelian symmetries.
Properties of modular Hamiltonians on entanglement plateaux
Authors: Abt Raimond , Erdmenger Johanna
Published: November 2018

Abstract

The modular Hamiltonian of reduced states, given essentially by the logarithm of the reduced density matrix, plays an important role within the AdS/CFT correspondence in view of its relation to quantum information. In particular, it is an essential ingredient for quantum information measures of distances between states, such as the relative entropy and the Fisher information metric. However, the modular Hamiltonian is known explicitly only for a few examples. For a family of states ρ

λ
that is parametrized by a scalar λ, the first order contribution in

$$ \overset{\sim }{\lambda } = \lambda -{\lambda}_0 $$

λ
∼

=

λ
−

λ
0

of the modular Hamiltonian to the relative entropy between ρλ and a reference state ρλ
0 is completely determined by the entanglement entropy, via the first law of entanglement. For several examples, e.g. for ball-shaped regions in the ground state of CFTs, higher order contributions are known to vanish. In these cases the modular Hamiltonian contributes to the Fisher information metric in a trivial way. We investigate under which conditions the modular Hamiltonian provides a non-trivial contribution to the Fisher information metric, i.e. when the contribution of the modular Hamiltonian to the relative entropy is of higher order in

$$ \overset{\sim }{\lambda } $$

λ
∼

. We consider one-parameter families of reduced states on two entangling regions that form an entanglement plateau, i.e. the entanglement entropies of the two regions saturate the Araki-Lieb inequality. We show that in general, at least one of the relative entropies of the two entangling regions is expected to involve

$$ \overset{\sim }{\lambda } $$

λ
∼

contributions of higher order from the modular Hamiltonian. Furthermore, we consider the implications of this observation for prominent AdS/CFT examples that form entanglement plateaux in the large N limit.
Two-loop scattering amplitudes from ambitwistor strings: from genus two to the nodal Riemann sphere
Authors: Geyer Yvonne , Monteiro Ricardo
Published: November 2018

Abstract

We derive from ambitwistor strings new formulae for two-loop scattering amplitudes in supergravity and super-Yang-Mills theory, with any number of particles. We start by constructing a formula for the type II ambitwistor string amplitudes on a genus-two Riemann surface, and then study the localisation of the moduli space integration on a degenerate limit, where the genus-two surface turns into a Riemann sphere with two nodes. This leads to scattering amplitudes in supergravity, expressed in the formalism of the two-loop scattering equations. For super-Yang-Mills theory, we import ‘half’ of the supergravity result, and determine the colour dependence by considering a current algebra on the nodal Riemann sphere, thereby completely specifying the two-loop analogue of the Parke-Taylor factor, including non-planar contributions. We also present in appendices explicit expressions for the Szegő kernels and the partition functions for even spin structures, up to the relevant orders in the degeneration parameters, which may be useful for related investigations in conventional superstring theory.
Collider production of electroweak resonances from γγ states
Authors: Delgado Rafael L. , Dobado Antonio , Espada Miguel , Llanes-Estrada Felipe J. , Merino Iván León
Published: November 2018

Abstract

We estimate production cross sections for 2-body resonances of the Electroweak Symmetry Breaking sector (in W

L

W

L
and Z

L

Z

L
rescattering) from γγ scattering. We employ unitarized Higgs Effective Field Theory amplitudes previously computed coupling the two photon channel to the EWSBS. We work in the Effective Photon Approximation and examine both e
−
e
+ collisions at energies of order 1–2 TeV (as relevant for future lepton machines) and pp collisions at LHC energies. Dynamically generating a spin-0 resonance around 1.5 TeV (by appropriately choosing the parameters of the effective theory) we find that the differential cross section per unit s, p

t

2
is of order 0.01 fbarn/TeV4 at the LHC. Injecting a spin-2 resonance around 2 TeV we find an additional factor 100 suppression for p

t
up to 200 GeV. The very small cross sections put these γγ processes, though very clean, out of reach of immediate future searches.
Instability wave–streak interactions in a high Mach number boundary layer at flight conditions
Authors: Paredes Pedro , Choudhari Meelan M. , Li Fei
Published: November 2018

The interaction of stationary streaks undergoing non-modal growth with modally unstable instability waves in a high Mach number boundary-layer flow is studied using numerical computations. The geometry and flow conditions are selected to match a relevant trajectory location from the ascent phase of the HIFiRE-1 flight experiment; namely, a $7^{\circ }$ half-angle, circular cone with $2.5$ mm nose radius, free-stream Mach number equal to $5.30$, unit Reynolds number equal to $13.42~\text{m}^{-1}$ and wall-to-adiabatic temperature ratio of approximately $0.35$ over most of the vehicle. This paper investigates the nonlinear evolution of initially linear optimal disturbances that evolve into finite-amplitude streaks, followed by an analysis of the modal instability characteristics of the perturbed, streaky boundary-layer flow. The investigation is performed with a stationary, full Navier–Stokes equations solver and the plane-marching parabolized stability equations (PSE), in conjunction with partial-differential-equation-based planar eigenvalue analysis. The overall effect of streaks is to reduce the peak amplification factors of instability waves, indicating a possible downstream shift in the onset of laminar–turbulent transition. The present study confirms previous findings that the mean-flow distortion of the nonlinear streak perturbation reduces the amplification rates of the Mack-mode instability. More importantly, however, the present results demonstrate that the spanwise varying component of the streak can produce a larger effect on the Mack-mode amplification. The analysis of planar and oblique Mack-mode waves modulated by the presence of the streaks shows that the planar Mack mode still dominates the instability characteristics of the flow. The study with selected azimuthal wavenumbers for the stationary streaks reveals that a wavenumber of approximately $1.4$ times larger than the optimal wavenumber is more effective in stabilizing the planar Mack-mode instabilities. In the absence of unstable first-mode waves for the present cold-wall condition, transition onset is expected to be delayed until the peak streak amplitude increases to nearly 35 % of the free-stream velocity, when intrinsic instabilities of the boundary-layer streaks begin to dominate the transition process. For streak amplitudes below that limit a significant net stabilization is achieved, yielding a potential transition delay that can exceed 100 % of the length of the laminar region in the uncontrolled case.
A uniform momentum zone–vortical fissure model of the turbulent boundary layer
Authors: Bautista Juan Carlos Cuevas , Ebadi Alireza , White Christopher M. , Chini Gregory P. , Klewicki Joseph C.
Published: November 2018

Recent studies reveal that at large friction Reynolds number $\unicode[STIX]{x1D6FF}^{+}$ the inertially dominated region of the turbulent boundary layer is composed of large-scale zones of nearly uniform momentum segregated by narrow fissures of concentrated vorticity. Experiments show that, when scaled by the boundary-layer thickness, the fissure thickness is $\mathit{O}(1/\sqrt{\unicode[STIX]{x1D6FF}^{+}})$, while the dimensional jump in streamwise velocity across each fissure scales in proportion to the friction velocity $u_{\unicode[STIX]{x1D70F}}$. A simple model that exploits these essential elements of the turbulent boundary-layer structure at large $\unicode[STIX]{x1D6FF}^{+}$ is developed. First, a master wall-normal profile of streamwise velocity is constructed by placing a discrete number of fissures across the boundary layer. The number of fissures and their wall-normal locations follow scalings informed by analysis of the mean momentum equation. The fissures are then randomly displaced in the wall-normal direction, exchanging momentum as they move, to create an instantaneous velocity profile. This process is repeated to generate ensembles of streamwise velocity profiles from which statistical moments are computed. The modelled statistical profiles are shown to agree remarkably well with those acquired from direct numerical simulations of turbulent channel flow at large $\unicode[STIX]{x1D6FF}^{+}$. In particular, the model robustly reproduces the empirically observed sub-Gaussian behaviour for the skewness and kurtosis profiles over a large range of input parameters.
A model of tear-film breakup with continuous mucin concentration and viscosity profiles
Authors: Dey Mohar , Vivek Atul S. , Dixit Harish N. , Richhariya Ashutosh , Feng James J.
Published: November 2018

We propose an alternative to the prevailing framework for modelling tear-film breakup, which posits a layered structure with a mucus layer next to the cornea and an aqueous layer on top. Experimental evidence shows continuous variation of mucin concentration throughout the tear film, with no distinct boundary between the two layers. Thus, we consider a continuous-viscosity model that replaces the mucus and aqueous layers by a single liquid layer with continuous profiles of mucin concentration and viscosity, which are governed by advection–diffusion of mucin. The lipids coating the tear film are treated as insoluble surfactants as previously, and slip is allowed on the ocular surface. Using the thin-film approximation, we carry out linear stability analysis and nonlinear numerical simulations of tear-film breakup driven by van der Waals attraction. Results show that for the same average viscosity, having more viscous material near the ocular surface stabilizes the film and prolongs the breakup time. Compared with the layered models, the continuous-viscosity model predicts film breakup times that are in better agreement with experimental data. Finally, we also suggest a hydrodynamic explanation for how pathological loss of membrane-associated mucins may lead to faster breakup.
Generalized slip condition over rough surfaces
Authors: Zampogna Giuseppe A. , Magnaudet Jacques , Bottaro Alessandro
Published: November 2018

A macroscopic boundary condition to be used when a fluid flows over a rough surface is derived. It provides the slip velocity $\boldsymbol{u}_{S}$ on an equivalent (smooth) surface in the form $\boldsymbol{u}_{S}=\unicode[STIX]{x1D716}{\mathcal{L}}\boldsymbol{ : }{\mathcal{E}}$, where the dimensionless parameter $\unicode[STIX]{x1D716}$ is a measure of the roughness amplitude, ${\mathcal{E}}$ denotes the strain-rate tensor associated with the outer flow in the vicinity of the surface and ${\mathcal{L}}$ is a third-order slip tensor arising from the microscopic geometry characterizing the rough surface. This boundary condition represents the tensorial generalization of the classical Navier slip condition. We derive this condition, in the limit of small microscopic Reynolds numbers, using a multi-scale technique that yields a closed system of equations, the solution of which allows the slip tensor to be univocally calculated, once the roughness geometry is specified. We validate this generalized slip condition by considering the flow about a rough sphere, the surface of which is covered with a hexagonal lattice of cylindrical protrusions. Comparisons with direct numerical simulations performed in both laminar and turbulent regimes allow us to assess the validity and limitations of this condition and of the mathematical model underlying the determination of the slip tensor ${\mathcal{L}}$.