bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultra‐broadband quantification of CMOS varactors based on vector standing wave measurements in a non‐linear transmission line
Authors: Jamshidifar Mehran , Bolívar Peter Haring
Published: February 2019

By near‐filed scanning of a non‐linear transmission line (NLTL), both the magnitude and the phase patterns of standing waves are measured. The patterns demonstrate the internal behavior of the NLTL such as inter‐section mismatch, which is not observable by means of microwave network analysers at the device ports. With the analysis of standing waves, transmission line parameters such as the effective permittivity, the characteristics impedance, and varactor capacitances are quantified over a broad frequency range from 10 to 90 GHz.
Tunable eight‐element MIMO antenna based on the antenna cluster concept
Authors: Hannula Jari‐Matti , Saarinen Tapio O. , Lehtovuori Anu , Holopainen Jari , Viikari Ville
Published: February 2019

Realising capacity demands of future wireless communications require improved spectral efficiency in the sub‐6 GHz frequency bands. This study proposes a novel eight‐element multiple‐input–multiple‐output (MIMO) antenna that can be tuned from 1.7 to 6 GHz. The design is based on the antenna cluster concept, where weighted feeding of multiple antenna elements is used to modify the operating frequency. This study extends the theory of the concept to account for multiple separate clusters, thus enabling it to be used for MIMO. The proposed antenna achieves over 60% efficiency at frequencies above 3 GHz, and the system exceeds the ergodic capacity of the ideal 7 × 7 MIMO in that band.
Non‐isolated buck–boost dc–dc converter with quadratic voltage gain ratio
Authors: Gorji Saman A. , Mostaan Ali , Tran My Hung , Ektesabi Mehran
Published: February 2019

A new transformer‐less buck–boost converter is proposed, which owns a quadratic voltage gain ratio. The proposed converter (a) has only one active switch, which makes the implementation of the gate driver and control system simpler; (b) has a quadratic voltage gain without using a transformer, which equips the designers to obtain a high‐voltage gain ratio and avoid the complexity of magnetic utilisations; (c) works both in step‐up or step‐down mode, while most of the existing quadratic topologies are able to work either in step‐up or step‐down mode; and (d) shares a common ground between the input and output terminals. The operating states of the proposed converter along with its steady‐state performance are analysed. Then, the small‐signal modelling and the power loss analysis are performed. A comparison shows the unique features of the converter, specifically in terms of voltage gain ratio and the count of power switches. Finally, the experimental results of a laboratory prototype, as well as the simulation results from PSIM software, are used for validation. The converter was tested in different conditions to inspect its transient response and to record its efficiency. The maximum recorded efficiencies in boost and buck modes, respectively were 94.7 and 93%.
Robust three degrees of freedom based on H∞ controller of voltage/current loops for DG unit in micro grids
Authors: Bouzid Allal El Moubarek , Sicard Pierre , Chaoui Hicham , Cheriti Ahmed
Published: February 2019

This study proposes a cascaded voltage–current robust control strategy for a distributed generator (DG) in microgrids. The main objective of the proposed controller is to improve the performance and power quality of a DG by injecting simultaneously a good sinusoidal voltage/current to the different loads connected to the DG. The proposed cascaded voltage/current controller consists of three degree‐of‐freedom controller, which is designed by using H∞ control theory based on mixed sensitivity specifications. The choices of appropriate weighting functions Wt, Wu, Wy that satisfy the preset goals to get a robust controller and a transform to a standard H∞ control design problem based on pre‐compensator, feedforward and feedback connections are presented. The 3DOF‐controller is based on MATLAB R/SimPowerSystems and using RT‐EVENTS‐toolbox. The controller is evaluated under different scenarios: transient responses with a resistive local load, and loads disturbances in steady‐state responses with resistive, resistive inductive, resistive capacitive, and non‐linear loads. Simulation and experimental results of resulting waveforms from a DG unit are presented, it confirms the effectiveness of the proposed method in effectively rejecting perturbation and robustness to loads disturbances; both good reference tracking and good transient response, and finally significantly lead to a very low total harmonic distortion.
Deep learning for waveform estimation and imaging in passive radar
Authors: Yonel Bariscan , Mason Eric , Yazici Birsen
Published: February 2019

The authors consider a bistatic configuration with a stationary transmitter transmitting unknown waveforms of opportunity and a single moving receiver and present a deep learning (DL) framework for passive synthetic aperture radar (SAR) imaging. They approach DL from an optimisation based perspective and formulate image reconstruction as a machine learning task. By unfolding the iterations of a proximal gradient descent algorithm, they construct a deep recurrent neural network (RNN) that is parameterised by the transmitted waveforms. They cascade the RNN structure with a decoder stage to form a recurrent auto‐encoder architecture. They then use backpropagation to learn transmitted waveforms by training the network in an unsupervised manner using SAR measurements. The highly non‐convex problem of backpropagation is guided to a feasible solution over the parameter space by initialising the network with the known components of the SAR forward model. Moreover, prior information regarding the waveform structure is incorporated during initialisation and backpropagation. They demonstrate the effectiveness of the DL‐based approach through numerical simulations that show focused, high contrast imagery using a single receiver antenna at realistic signal‐to‐noise‐ratio levels.
Topology optimisation method for MACL formation based on acoustic measurement network
Authors: Xu Bo , Wang Xiaoyu , Razzaqi Asghar Abbas , Zhang Xun
Published: February 2019

The topology of formation is an important factor that directly affects the performance of multiple autonomous underwater vehicle (AUV) cooperative localisation (MACL). This study presents a new optimisation design method, and the main contributions are as follows: (i) the evaluation function of the observable performance is constructed based on Cramér–Rao lower bound and Fisher information matrix considering the factors such as the situation of multiple leaders and multiple followers (MLs–MFs) and the correlation between acoustic ranging error and distance. (ii) In view of the uncertainty of the location information, the Monte Carlo method was applied to complete the reconstruction of the evaluation function and the formation configuration in the possible distribution region is optimised. (iii) A step recursive strategy based on annealing idea is proposed to solve the constraint equation for ML–MF system. The simulation results show that the MACL system composed of three leaders (3Ls) and one follower or 3Ls and three followers can complete the optimal formation configuration under position certainty or uncertainty. In addition, the proposed recursive strategy makes the iterative result no longer dependent on the selection of initial position, and the iterative process is no longer interfered by the local optimal solution.
Understanding the electrical, thermal, and mechanical properties of epoxy magnesium oxide nanocomposites
Authors: Peddamallu Nagachandrika , Nagaraju Guvvala , Sridharan Krishnamurth , Velmurugan Ramachandran , Vasa Nilesh Jayantilal , Nakayama Tadachika , Sarathi Ramanujam
Published: February 2019

Epoxy MgO nanocomposites exhibit high surface discharge inception voltage (SDIV) in SF6 gas ambience. Increase in SDIV is observed with 3wt% of MgO‐added epoxy nanocomposites, especially when the SF6 ambient gas pressure is high. Impact of thermal ageing of epoxy nanocomposites on SDIV is minimum. Dielectric response studies were carried out experimentally and compared with modelling studies. The surface potential decay and charge trap characteristics of epoxy nanocomposites vary with percentage of nano filler. Thermal aging of epoxy nanocomposites has less influence on surface potential decay characteristics for 1 and 3 wt% MgO‐added epoxy nanocomposites, indicating anti‐thermal aging characteristics. Surface discharge activity generates UHF with its dominant frequency at around 1 GHz. The UHF signal magnitude formed due to SD activity is minimum with 3 wt% MgO‐added epoxy nanocomposites. Laser‐induced breakdown spectroscopy (LIBS) studies indicate that plasma temperature and threshold fluence increases with increase in wt% of MgO in epoxy resin. Tensile and flexural properties are greatly improved for nanocomposite compared to epoxy. The dynamic mechanical analysis (DMA) indicates increased storage modulus and reduction of tan δ with epoxy nanocomposites. The glass transition temperature (Tg) and activation energy increases with wt % of nano filler.
One‐pot synthesis of the fluorocarbon quantum dots for sensitively detecting Fe3+
Authors: Wang Ning , Ai Jun
Published: February 2019

In this work, the novel method of generating fluorocarbon quantum dots (FQDs) in aqueous solution is demonstrated. The FQDs were synthesised by milk at high temperature and high‐pressure hydrothermal method, which were the only raw material. They synthesised high fluorescence, green FQDs. The Fe3+ was added to FQDs, the fluorescence signal was quenched effectively. The fluorescence of FQDs showed a good linear relationship with the change of Fe3+ concentration (50–700 μmol/l), and FQDs selected Fe3+ to complete detection. Finally, the authors applied the prepared FQDs to the real samples to detect the Fe3+ in the water. The iron ions belong to the Yellow River water, which is detected about 90.6–107%, and it is indicated that this method can be applied to detect iron ions in actual water samples. They successfully used milk to synthesis the FQDs, and it had high selectivity for Fe3+. So the authors’ think the FQDs has great potential in the field.
Synthesis and characterisation of VG nanosheets on silica aerogel by plasma‐enhanced chemical vapour deposition method
Authors: Vigneswari S. , Murugesan S.
Published: February 2019

Vertical graphene (VG) nanosheets are directly grown on silica aerogel and silicon substrate (100) by plasma‐enhanced chemical vapour deposition process in the presence of hydrogen as a reducing agent at atmospheric pressure at 800°C. The physiochemical properties of the nanohybrid were thoroughly characterised by Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The presence of full wave half maximum of D, G and D′ indicates VG nanowalls. The height (≅50 nm) of the VG nanowalls were confirmed by SEM and Raman spectroscopy but AFM reveals it as ≅ 15 nm. Surface and cross‐sectional SEM show the uniform distribution of vertical growth of nanowalls and the AFM revealed surface morphology of VG nanowalls.
Ultrasonic bonding method controlled by the characteristic waveform of ultrasonic propagation
Authors: Sun Yibo , Teng Tiandong , Guo Guoqing , Wu Guoxiong
Published: February 2019

The vibration propagated in polymer components is related to the interfacial fusion in ultrasonic bonding process, which can be employed to be reference variables to control the ultrasonic energy. In this paper, an ultrasonic precise bonding method controlled by characteristic waveform from the wavelet decomposition of the ultrasonic propagation is proposed. The vibration propagated from ultrasonic horn, through polymer components, to the anvil finally is analysed by wavelet packet decomposition. The node signal in the frequency band of 109,375–125,000 Hz, which contains more information related to the interfacial fusion behaviour, is reconstructed as the characteristic waveform. The ultrasonic bonding control procedure is designed by the recognition of two characteristic points on the characteristic waveform. Results indicate that, at the second characteristic point, high‐quality interfacial fusion bonding is achieved without overflow out of the edge.
Plasmonic nano bow‐tie arrays with enhanced LSPR refractive index sensing
Authors: Khoshdel Vahid , Shokooh‐Saremi Mehrdad
Published: February 2019

In this work, the performance of the nano bow‐tie arrays for biosensing applications has been investigated. Since the geometrical parameters of the device such as the bow‐tie length and gap size have major effects on the system's optical response, a parametric study based on finite‐difference time‐domain (FDTD) method has been conducted. In order to enhance the sensitivity, two bow‐tie shaped nanoparticles in the form of 2 × 1 and 2 × 2 arrays have been developed. In the case of TM polarisation, a sensitivity up to 923 nm/RIU with a figure of merit (FOM) of 5.5 has been obtained for 2 × 2 nano bow‐tie array. Moreover, the performance of the proposed nanoparticles for TE polarisation has been evaluated and a FOM exceeding 15.9 has been achieved for single nano bow‐tie. According to this study, the proposed nano bow‐tie structures have a great potential for sensing and detection applications.
Diameter optimisation for highest DoB of CNT‐FETs
Authors: Khan Imtiaj , Morshed Ovishek , Mominuzzaman Sharif Mohammad
Published: February 2019

Carbon nanotube (CNT) is one of the most significant materials for the development of faster and improved performance of nanoscaled transistors. This work aims at analysing a trade‐off between device performance and device size of CNT‐based transistor. Acoustic and optical phonon (OP) scattering along with the elastic scattering lead to the non‐ballistic performances of those transistors. The main focus of this work is mainly on finding an optimum diameter to obtain the highest degree of ballisticity (DoB) from both single‐walled (SWCNT‐FET) and double‐walled CNT field‐effect transistors (DWCNT‐FET). At first, an n ‐type SWCNT‐FET has been considered and the diameter dependence on DoB has been simulated. The effects of drain voltage, gate voltage and channel length have been investigated for such characteristics followed by a comparison with DWCNT‐FET structure. First of all, it has been found that DoB along with the optimum diameter increases with the increase of (VDS–VGS). The increase of channel length, however, degrades the ballistic performance demanding a higher diameter to reach the optimum point. Finally, it can be concluded that optimum diameter for DWCNT‐FET reaches earlier than SWCNT‐FET but at lower DoB.
Graphene nanosheets‐Inconel 718 nanocomposites fabricated by spark plasma sintering of in‐situ grown vertically standing graphene nanosheets‐Inconel 718 powders
Authors: Chen Dongsheng , Zhou Haitao , Tian Ye , Luo Fei , Liu Dabo , Luo Bingwei
Published: February 2019

The present work reports a mechanical improvement in nickel‐based nanocomposites reinforced by in‐situ grown graphene nanosheets (GNSs). First, vertically standing GNSs (VSGNSs) were grown on Inconel 718 alloy (718) powders by plasma‐enhanced chemical vapour deposition. Then these powders were used to fabricate GNSs‐718 nanocomposites by using spark plasma sintering method. The microstructure and mechanical properties of the nanocomposites were investigated by Raman spectroscopy, scanning electron microscopy, transmission electron microscopy and tensile tests. Testing results showed that three‐dimensional net structured VSGNSs were in‐situ grown on surfaces of 718 powders. GNSs‐718 nanocomposites exhibited homogeneously dispersed GNSs, which distributed mainly along grain boundaries. Transmission electron microscopy indicated that there were clean and strong interfaces between GNSs and nickel‐based matrix. Compared to the unreinforced 718 alloy, GNSs‐718 nanocomposites showed increased strength and elongation. The relevant strengthening mechanisms involved in GNSs‐718 nanocomposites were discussed.
The CARMA-NRO Orion Survey
Authors: Suri Sümeyye , Sánchez-Monge Álvaro , Schilke Peter , Clarke Seamus D. , Smith Rowan J. , Ossenkopf-Okada Volker , Klessen Ralf , Padoan Paolo , Goldsmith Paul , Arce Héctor G. , Bally John , Carpenter John M. , Ginsburg Adam , Johnstone Doug , Kauffmann Jens , Kong Shuo , Lis Dariusz C. , Mairs Steve , Pillai Thushara , Pineda Jaime E. , Duarte-Cabral Ana
Published: February 2019

Context. We present an initial overview of the filamentary structure in the Orion A molecular cloud utilizing a high angular and velocity resolution C18O(1–0) emission map that was recently produced as part of the CARMA-NRO Orion Survey.

Aims. The main goal of this study is to build a credible method to study varying widths of filaments which has previously been linked to star formation in molecular clouds. Due to the diverse star forming activities taking place throughout its ~20 pc length, together with its proximity of 388 pc, the Orion A molecular cloud provides an excellent laboratory for such an experiment to be carried out with high resolution and high sensitivity.

Methods. Using the widely-known structure identification algorithm, DisPerSE, on a three-dimensional (PPV) C18O cube, we identify 625 relatively short (the longest being 1.74 pc) filaments over the entire cloud. We studied the distribution of filament widths using FilChaP, a python package that we have developed and made publicly available.

Results. We find that the filaments identified in a two square-degree PPV cube do not overlap spatially, except for the complex OMC-4 region that shows distinct velocity components along the line of sight. The filament widths vary between 0.02 and 0.3 pc depending on the amount of substructure that a filament possesses. The more substructure a filament has, the larger is its width. We also find that despite this variation, the filament width shows no anticorrelation with the central column density which is in agreement with previous Herschel observations.
Galactic Archaeology with asteroseismic ages: Evidence for delayed gas infall in the formation of the Milky Way disc
Authors: Spitoni E. , Silva Aguirre V. , Matteucci F. , Calura F. , Grisoni V.
Published: February 2019

Context. Precise stellar ages from asteroseismology have become available and can help to set stronger constraints on the evolution of the Galactic disc components. Recently, asteroseismology has confirmed a clear age difference in the solar annulus between two distinct sequences in the [α/Fe] versus [Fe/H] abundance ratios relation: the high-α and low-α stellar populations.

Aims. We aim to reproduce these new data with chemical evolution models including different assumptions for the history and number of accretion events.

Methods. We tested two different approaches: a revised version of the “two-infall” model where the high-α phase forms by a fast gas accretion episode and the low-α sequence follows later from a slower gas infall rate, and the parallel formation scenario where the two disc sequences form coevally and independently.

Results. The revised two-infall model including uncertainties in age and metallicity is capable of reproducing: i) the [α/Fe] versus [Fe/H] abundance relation at different Galactic epochs, ii) the age−metallicity relation and the time evolution [α/Fe]; iii) the age distribution of the high-α and low-α stellar populations, iv) the metallicity distribution function. The parallel approach is not capable of properly reproducing the stellar age distribution, in particular at old ages.

Conclusions. The best chemical evolution model is the revised two-infall one, where a consistent delay of ∼4.3 Gyr in the beginning of the second gas accretion episode is a crucial assumption to reproduce stellar abundances and ages.
Investigation of the molecular signatures of selection on ATP synthase genes in the marine bivalveLimecola balthica
Authors: Pante Eric , Becquet Vanessa , Viricel Amélia , Garcia Pascale
Published: February 2019

We used transcriptomic sequence data to describe patterns of divergence and selection across different populations of a marine bivalve (Limecola balthica). Our analyses focused on a nuclear gene (atp5c1) that was previously detected in anFSTscan as highly structured among populations separated by the Finistère Peninsula in France. This gene encodes the gamma subunit of the FO/F1ATP synthase, a multi-protein complex that is paramount to cellular respiration and energy production. Analysis of non-synonymous to synonymous mutation ratios revealed that 65% of the gene is highly conserved (dN/dS≤ 0.1, min = 0), while 6% of the gene is likely under positive selection (dN/dS≥ 1, max = 2.03). All replacement mutations are clustered on a 46 residues portion of the protein, within an inter-peptide interaction zone. Comparative genomics suggests that these mutations are evolutionarily stable, and we hypothesize that they are involved in inter-population genetic incompatibilities with other subunits of the ATP synthase complex. The protein stability of the gamma subunit conferred by southern variants was inferred to be higher under warmer temperatures, suggesting that environmental conditions may contribute to the strength of genetic barriers inL. balthica.
From the microstructure of steels to the explosion of sparks
Authors: Guillen Anthony , Goh Fang , Andre Julie , Barral Amaury , Brochet Clement , Louis Quentin , Guillet Thibault
Published: February 2019

Sparks ejected by the grinding of steel can be observed to split in mid-flight. In this paper, we investigate the link between steel microstructure and the splitting behavior using two different steels: hypoeutectoid (containing less than 0:8% carbon) and hypereutectoid (>0:8% carbon). We used a high-speed camera filming at 1000 fps to observe the sparks, and a Scanning Electron Microscope to image the microstructures. For the hypoeutectoid steel, we also quantified the splitting behavior of the sparks by measuring the statistical distribution of the linear distance they travel before splitting occurs. We find that our results are coherent with the common explanation of the splitting phenomenon, stating that sparks split because their microstructures allow the formation of pockets of CO2 by oxidation of Fe3C, producing an internal pressure and leading to explosion.
Research infrastructures as a key optimizer of european research
Authors: Rossi Giorgio
Published: February 2019

The European Strategy Forum on Research Infrastructures (ESFRI) has been created to advise the Competitiveness Council of the European Union on the needs and opportunities to build a strong Research Infrastructure (RI) system, covering all domains of research, providing the most advanced tools that cannot be realized at national level, and that must be accessible to all strongly motivated researchers in order to increase the European science competitiveness.
Econophysics: still fringe after 30 years?
Authors: Bouchaud JP
Published: February 2019

It is customary to date the initial foray of physicists into economics to the September 1987 Santa Fe conference on “Economics as a complex evolving system", organised by two famous physicists (Phil Anderson & David Pines) and one famous economist (Ken Arrow). When confronted with the theories of Rational Expectations and Efficient Markets, then at the peak of their glory, Phil Anderson famously quipped: Do you guys really believe that? Many inspiring and insightful ideas were discussed during that conference [1], suggesting a potentially productive cross-fertilisation between economics and the (back then) nascent theory of complex systems.
Activité physique à domicile pour les seniors : revue de la question et proposition d’une pratique optimisée
Authors: Bigot Lucile , Langeard Antoine , Moussay Sébastien , Gauthier Antoine , Quarck Gaëlle
Published: February 2019

Les altérations physiologiques et fonctionnelles liées au vieillissement peuvent avoir un impact sur l’autonomie des personnes dans les activités de la vie quotidienne. Afin de prévenir et de limiter ces effets délétères, il est recommandé d’avoir une activité physique adaptée régulière. Cependant, l’accès à un entraînement efficace n’est pas toujours possible pour les seniors. Dans une première partie, nous examinons donc l’état des connaissances scientifiques sur les différentes modalités d’entraînement au domicile d’un public âgé. En l’absence de supervision, il apparaît que les bénéfices associés à la pratique sont moindres et que l’adhésion au programme est réduite. Dans le cadre d’entraînements à domicile semi-supervisés, il semble que les bénéfices sur la santé soient encore une fois faibles. Lors d’entraînements à domicile avec supervision à distance, l’adhésion et les effets sur la santé semblent cette fois plus importants. Ainsi, afin de répondre aux problématiques relevées par cette revue, dans la seconde partie de ce travail nous présentons un projet novateur d’accompagnement à distance par un professionnel au moyen d’un système de visioconférence collectif. La mise en place de ce projet est prometteuse puisque les résultats préliminaires montrent des taux d’adhésion, d’observance et un niveau de satisfaction très élevés.
STEP as a Useful Tool to Screen for Diabetes-Specific Health-Related
Problems in Community-Based Geriatric Patients- An Exploratory Secondary
Analysis of Cross-Sectional Data
Authors: Carmienke Solveig , Geier Anne-Kathrin , Deutsch Tobias , Rasche Franz Maximilian , Frese Thomas
Published: February 2019

Background and Aims Comprehensive geriatric assessments are established
tools for the identification of health problems in the elderly. So far, little
is known about tailoring and targeting to facilitate their application. As a
starting point for a tailored assessment of patients with diabetes, a highly
prevalent health condition, we aimed to assess if the Standardized Assessment of
Elderly People (STEP) is able to identify relevant differences in self-reported
health problems between diabetic and non-diabetic patients.

Patients and Methods We performed a secondary analysis of a
cross-sectional study including 1007 adults (aged 65 and older) from 28 German
general practices, evaluating the feasibility and usefulness of the
self-administered STEP version. For this exploratory study we re-analysed the
data and compared patients with and without diabetes.

Results Out of 940 patients included in the secondary analysis, 248
(26.4%) had diabetes. Compared to non-diabetic patients, geriatric
diabetic patients reported more often problems in activities of daily living,
physical problems typically associated with diabetes such as urinary
incontinence, visual impairment, mood disturbances, as well as the use of
medical or social services. Most of our results were stable after adjusting for
age, sex and body mass index.

Conclusion We conclude that the self-administered version of the STEP
tool may be used to screen for health problems typically associated with
diabetes. Our results may guide the development of a tailored STEP-version
specifically for diabetic patients. Further research might evaluate the adoption
and usefulness of such a tool in every-day general practice.
Kutane nichttuberkulöse Mykobakteriosen
Authors: Emmerich K. , Kolb-Mäurer A. , Goebeler M.
Published: February 2019

Atypische Mykobakterien sind eine heterogene Gruppe ubiquitär vorkommender Umwelt-Saprophyten, die zu oberflächlichen und tiefen Hautinfektionen bis hin zu Hautinfektionen mit Systembeteiligung führen können. Die Erreger vermögen nach Bagatellverletzungen in die Haut einzudringen und führen insbesondere bei Immunsupprimierten zu schweren Infektionen. Klinisch werden schnell und langsam wachsende atypische Mykobakterien unterschieden. Für die Dermatologie wichtige Vertreter der langsam wachsenden Mykobakterien sind M. marinum, M. ulcerans und M. haemophilum. M. marinum verursacht das Schwimmbad- bzw. Aquariumgranulom, die in westlichen Industriestaaten häufigste atypische Mykobakteriose der Haut. M. ulcerans ist der Erreger der weltweit häufigsten kutanen atypischen Mykobakteriose und verursacht v. a. in Westafrika das sog. Buruli-Ulkus. M. haemophilum wird besonders bei Immunsupprimierten und bei Kindern mit begleitender zervikaler und perihilärer Lymphadenitis beobachtet. Zu den schnellwachsenden atypischen Mykobakterien gehören M. abscessus, M. chelonae und M. fortuitum. Relevant sind sie insbesondere als Verursacher von kutanen Mykobakteriosen, die in Zusammenhang mit iatrogener Immunsuppression sowie medizinischen und kosmetischen Prozeduren stehen. Das Management von NTM stellt eine besondere Herausforderung dar: Das klinische Erscheinungsbild ist vielfältig, die Diagnostik schwierig und die antibiotische Kombinationstherapie nicht standardisiert.
Transhepatic forceps biopsy after PTCD for histological assessment of bile duct stenoses or occlusions
Authors: Warnken Eva-Marie , Uder Michael , Stein Hubert , Wucherer Michael , Lell Michael , Muschweck Herbert , Adamus Ralf
Published: February 2019

Purpose The goal of this study was to evaluate the experience of 11 years of wire-guided forceps biopsy via PTCD in patients with obstructive jaundice.

Materials and methods In a retrospective approach, 56 biopsies in 51 patients were analyzed (22 female, 29 male). Data was collected from 2006 to 2016. Mean age was 71 years (range: 34 – 86 years). Data was extracted from dig. Patients’ records (KIS, PACS, RIS) to be analyzed in Microsoft Excel.

Results All 56 procedures were technically successful. Stenosis in anastomoses were benign due to scarring in 7 patients and in 9 due to papillitis or others. In 4 patients, results in anastomosis were malignant. In 19 patients without anastomosis, CCC was the diagnosis, thereof 10 klatskin, 9 stenosis in other locations, followed by gastric, pancreatic, and colon carcinoma in 5, 3, and 2 patients. Three patients had a CUP (multimetering in case of more than 1 related category). Overall results were 35 mal. and 16 benign, 76.8 % of all proc. had a correct histopathologic result, and 23.2 % were false negative. Sensitivity was 65.8 %, which results in negative predictive value of 58.1 %. There was no false positive and so specificity was 100 %, as was the positive predictive value. False negative results (no malignancy but clinically and imaging suspect) were corrected by rerunning the procedure, by CT-guided biopsy or by 1 PET-CT. In 1 case the surg. sample brought the result. Minor complications occurred in 8 patients: shivering in 1 case, distinct but hemodynamically not relevant hemobilia in 5 cases, 2 portovenal bleedings. All bleedings were short-term and self-limiting.

Conclusion Despite good feasibility, low peri- and post-interv. risk and high validity the forceps biopsy via PTCD is not widely used. For experienced interventionalists, it is an effective method for obtaining histology.
Higher Axial Tibiofemoral Rotation and Functional Outcomes with Mobile-Bearing Compared with Fixed-Bearing Total Knee Arthroplasty at 1- but Not at 2-Year Follow-Up—A Randomized Clinical Trial
Authors: Amaro Joicemar Tarouco , Novaretti João Victor , Astur Diego Costa , Cavalcante Elton Luiz Batista , Rodrigues Junior Adilson Góes , Debieux Pedro , Kaleka Camila Cohen , Cohen Moisés
Published: February 2019

The objective of this study was to determine in vivo knee kinematics and clinical outcomes of patients who underwent fixed- and mobile-bearing total knee arthroplasty (TKA) at 1- and 2-year follow-up. This prospective double-blinded randomized controlled trial was performed from November 2011 to December 2012. A total of 64 patients were randomized to fixed- and mobile-bearing TKA groups (32 patients in each group). All patients were evaluated with the following: three-dimensional in vivo knee kinematics analysis during gait, stepping up and stepping down stair steps, and getting up from and sitting on a chair; and knee range of motion and patient-reported outcome measures (Knee Outcome Survey Activities of Daily Living Scale [KOS-ADLS] and pain visual analog scale [VAS]) at 1- and 2-year follow-up. Descriptive statistics (means, standard deviations, and percentages) were calculated for all variables. The Kolmogorov–Smirnov test was used to test if variables were normally distributed. A Student's t-test was used to compare continuous variables between patients in the two groups. The chi-square test was used to compare the groups with respect to categorical variables. The α level for statistical significance was set at p < 0.05. The mean axial tibiofemoral rotation in patients who underwent mobile-bearing TKA was significantly higher during gait (13.3 vs. 10.7), stepping up (12.8 vs. 10) stair steps, and getting up (16.1 vs. 12.1) from a chair compared with fixed-bearing TKA patients at 1-year follow-up (p < 0.05). KOS-ADLS function score was significantly higher in the mobile-bearing compared with the fixed-bearing TKA group (32 vs. 27.7) at 1-year follow-up (p < 0.05). No significant difference in kinematics and clinical outcomes between fixed- and mobile-bearing TKA groups was observed at 2-year follow-up (p > 0.05). Based on the results of this study, mobile-bearing TKA allowed a higher degree of rotation when walking, stepping up stair steps, and standing up from a chair, and had higher functional outcomes compared with fixed-bearing TKA at 1-year follow-up. However, no difference in in vivo kinematics or in clinical outcomes was observed between fixed- and mobile-bearing prostheses at 2-year follow-up.
Demixing, surface nematization, and competing adsorption in binary mixtures of hard rods and hard spheres under confinement
Authors: Wu Liang , Malijevský Alexandr , Avendaño Carlos , Müller Erich A. , Jackson George
Published: February 2019

A molecular simulation study of binary mixtures of hard spherocylinders (HSCs) and hard spheres (HSs) confined between two structureless hard walls is presented. The principal aim of the work is to understand the effect of the presence of hard spheres on the entropically driven surface nematization of hard rod-like particles at surfaces. The mixtures are studied using a constant normal-pressure Monte Carlo algorithm. The surface adsorption at different compositions is examined in detail. At moderate hard-sphere concentrations, preferential adsorption of the spheres at the wall is found. However, at moderate to high pressure (density), we observe a crossover in the adsorption behavior with nematic layers of the rods forming at the walls leading to local demixing of the system. The presence of the spherical particles is seen to destabilize the surface nematization of the rods, and the degree of demixing increases on increasing the hard-sphere concentration.
Invariance of experimental observables with respect to coarse-graining in standard and many-body dissipative particle dynamics
Authors: Vanya Peter , Sharman Jonathan , Elliott James A.
Published: February 2019

Dissipative particle dynamics (DPD) is a well-established mesoscale simulation method. However, there have been long-standing ambiguities regarding the dependence of its (purely repulsive) force field parameter on temperature as well as the variation of the resulting experimental observables, such as diffusivity or surface tension, with coarse-graining (CG) degree. Here, we rederive the temperature dependence of DPD interaction parameter and revisit the role of the CG degree in standard DPD simulations. Consequently, we derive a scaling of the input variables that renders the system properties invariant with respect to CG degree and illustrate the versatility of the method by computing the surface tensions of binary solvent mixtures. We then extend this procedure to many-body dissipative particle dynamics and, by computing surface tensions of the same mixtures at a range of CG degrees, demonstrate that this newer method, which has not been widely applied so far, is also capable of simulating complex fluids of practical interest.
Differential colorimetry measurements of fluctuation growth in nanofilms exposed to large surface thermal gradients
Authors: Fiedler Kevin R. , McLeod Euan , Troian Sandra M.
Published: February 2019

Slender liquid nanofilms exposed to large surface thermal gradients are known to undergo thickness fluctuations, which rapidly self-organize into arrays of nanoprotrusions with a separation distance of tens of microns. We previously reported good agreement between measurements of the characteristic spacing and the wavelength of the most unstable mode predicted by a linear stability analysis based on a long wavelength thermocapillary model. Here, we focus on differential colorimetry measurements to quantify early time out-of-plane growth of protrusions for peak heights spanning 20 to 200 nm. Analysis of peak heights based on shape reconstruction reveals robust exponential growth. Good quantitative agreement of the growth rates with the thermocapillary model is obtained using a single fit constant to account for material parameters of nanofilms that could not be measured directly. These findings lend further support to the conjecture that the array protrusions uncovered almost two decades ago likely stem from a linear instability, whose growth rate is controlled by thermocapillary forces counterbalanced by capillary forces.
Large-scale surface modification to improve hydrophilicity through using a plasma brush operated at one atmospheric pressure
Authors: Li Xuechen , Liu Renjing , Li Xiaoni , Gao Kun , Wu Jiacun , Gong Dandan , Jia Pengying
Published: February 2019

A uniform plume with pulsed discharges is generated through using a plasma brush excited by a direct current power supply. The results indicate that the plume length increases with the increasing gas flow rate or dissipated power. The optical emission spectrum from the plasma brush reveals that active species are abundant in the plasma plume. Based on the spectrum, an electron density on the order of 1014 cm−3 is obtained, which increases with the increasing dissipated power and gas flow rate. After a single scan of the plasma brush on the polyethylene terephthalate surface, a uniform surface modification is achieved with an improved hydrophilic width of about 24 mm. The water contact angle of the surface decreases with the decreasing scanning velocity and nozzle-sample distance or the increasing dissipated power and gas flow rate. Moreover, the treated surface shows an aging behavior in 6 days. Raman spectra indicate that oxygen-containing polar groups are generated on the treated polyethylene terephthalate surface. The polar groups are contained in oxidized materials, which are observed by scanning electron microscopy.
Interaction and transfer of charged particles from an alternating current glow discharge in liquids: Application to silver nanoparticle synthesis
Authors: Thai Phuoc Van , Abe Shinnosuke , Kosugi Kenichiro , Saito Nobuo , Takahashi Kazumasa , Sasaki Toru , Kikuchi Takashi
Published: February 2019

In this study, we experimentally investigated the effect of charged particles generated from an alternating current glow discharge in liquids and the ability of these particles to synthesize silver nanoparticles. The measurement of the pH and electrical conductivity in liquids was performed to study the interface reactions and transfer of species from plasmas to liquids. Solutions of sodium hydroxide, de-ionized water, sodium nitrate, and silver nitrate were used in this study. We determined that the pH of de-ionized water and sodium hydroxide solutions was reduced to 4.0 during the discharge. However, the pH of nitrate salts evolved in two opposite stages, with an initial reduction within 3 min from the start of the discharge and a subsequent increase to alkaline values. The results also showed that spherical silver nanoparticles were generated in the silver nitrate solutions under the discharge. These results indicate that alternating current glow discharge generates both positive ions and free electrons when in contact with a liquid, leading to complex chemical transformations. This suggests that the proposed approach can be used for noble nanoparticle synthesis.
Conical intersections and nonadiabatic coupling terms in 1,3,5-C6H3F3+: A six state beyond Born-Oppenheimer treatment
Authors: Mukherjee Soumya , Dutta Joy , Mukherjee Bijit , Sardar Subhankar , Adhikari Satrajit
Published: February 2019

In order to circumvent numerical inaccuracy originating from the singularity of nonadiabatic coupling terms (NACTs), we need to perform kinetically coupled adiabatic to potentially coupled diabatic transformation of the nuclear Schrödinger Equation. Such a transformation is difficult to achieve for higher dimensional sub-Hilbert spaces due to inherent complicacy of adiabatic to diabatic transformation (ADT) equations. Nevertheless, detailed expressions of ADT equations are formulated for six coupled electronic states for the first time and their validity is extensively examined for a well-known radical cation, namely, 1,3,5-C6H3F3+ (TFBZ+). While implementing this formulation, we compute ab initio adiabatic potential energy surfaces (PESs) and NACTs within the low-lying six electronic states (X̃2E′′, Ã2A2′′, B̃2E′, and C̃2A2′), where several types of nonadiabatic interactions, like Jahn-Teller conical intersections (CI), accidental CIs, accidental seams (series of degenerate points), and pseudo Jahn-Teller interactions can be observed over the Franck-Condon region of nuclear configuration space. Those interactions are depicted by exploring degenerate components of C–C asymmetric stretching, C–C symmetric stretching, and C–C–C scissoring motion (Q9x, Q9y, Q10x, Q10y, Q12x, and Q12y) to compute complete active space self-consistent field level adiabatic PESs and NACTs as implemented in the MOLPRO quantum chemistry package. Subsequently, we perform the ADT using our newly devised fifteen (15) ADT equations to locate the position of CIs, verify the quantization of NACTs, and to construct highly accurate diabatic PESs.
A differential rate meter for real-time peak tracking in optically detected magnetic resonance at low photon count rates
Authors: Ambal Kapildeb , McMichael Robert D.
Published: February 2019

We describe a real-time method to obtain normalized differential count rate signals from modulated systems with photon detection at single-photon count rates. The method is demonstrated with a real-time peak-locking and frequency control to track magnetic field using optically detected magnetic resonance of nitrogen-vacancy centers in diamond. This procedure allows us to measure the magnetic field continuously with a sensitivity of 4.1 µT/Hz1/2 and to track magnetic field sweep rates up to 50 µT/s. The differential rate meter automates the processing of voltage pulse outputs from the photon detector and provides noise levels on par with traditional photon counting methods using digital counters.
A non-isentropic model and the method of characteristic line for the post-detonation expansion of aluminized explosives
Authors: Yuan Xiaoxia , Wu Cheng , An Fengjiang , Liao Shasha , Zhou Mingxue , Xue Dongyu
Published: February 2019

The entropy of the flow field could not keep constant due to a strong exothermic reaction of aluminum powders during the post-detonation expansion of the aluminized explosives. Therefore, a non-isentropic model incorporating the aluminum oxidation in the detonation products was established. To solve the non-isentropic expansion process analytically, it was assumed that the whole expansion process was divided into several time ranges and the flow field was isentropic in each time range. Besides, the method of characteristic line was applied to theoretically calculate the velocity of the metal plate driven by aluminized explosives. Moreover, the effects on the pressure, density, sound speed, and temperature of detonation products due to the change of the entropy were analyzed. Finally, the metal plate-pushing tests were conducted to measure the velocity of metal plate driven by aluminized explosives through the Photonic Doppler Velocimetry system, and the degree of aluminum reaction was calculated indirectly from the test results. By comparing the results based on the isentropic model and novel non-isentropic model, it was proved that the non-isentropic model could more correctly describe the driving process of detonation products of aluminized explosives.
Head-on collision of nonlinear solitary solutions to Vlasov-Poisson equations
Authors: Hosseini Jenab S. M. , Brodin G.
Published: February 2019

Nonlinear solitary solutions to the Vlasov-Poisson set of equations are studied in order to investigate their stability by employing a fully kinetic simulation approach. This study is carried out in the ion-acoustic regime for a collisionless, electrostatic, and Maxwellian electron-ion plasma. The trapped population of electrons is modeled based on the well-known Schamel distribution function. Head-on mutual collisions of nonlinear solutions are performed in order to examine their collisional stability. The findings include three major aspects: (I) These nonlinear solutions are found to be divided into three categories based on their Mach numbers, i.e., stable, semi-stable, and unstable. Semi-stable solutions indicate a smooth transition from stable to unstable solutions for the increasing Mach number. (II) The stability of solutions is traced back to a condition imposed on averaged velocities, i.e., net neutrality. It is shown that a bipolar structure is produced in the flux of electrons, early in the temporal evolution. This bipolar structure acts as the seed of the net-neutrality instability, which tips off the energy balance of nonlinear solution during collisions. As the Mach number increases, the amplitude of the bipolar structure grows and results in a stronger instability. (III) It is established that during mutual collisions, a merging process of electron holes can occur to a variety of degrees, based on their velocity characteristics. Specifically, the number of rotations of electron holes around each other (in the merging phase) varies. Furthermore, it is observed that in the case of a non-integer number of rotations, two electron holes exchange their phase space cores.
A graphene-based neutral particle detector
Authors: Warbinek J. , Leimbach D. , Lu D. , Wendt K. , Pegg D. J. , Yurgens A. , Hanstorp D. , Welander J.
Published: February 2019

A neutral particle detector is presented, in which the traditionally used target material, indium tin oxide (ITO), is replaced by graphene. The graphene-based detector enables collinear photodetachment measurements at a significantly shorter wavelength of light down to 230 nm compared to ITO-based detectors, which are limited at 335 nm. Moreover, the background signal from the photoelectric effect is drastically reduced when using graphene. The graphene based detector, reaching 1.7 eV further into the UV energy range, allows increased possibilities for photodetachment studies of negatively charged atoms, molecules, and clusters.
Generation of functional hepatocyte 3D discoids in an acoustofluidic bioreactor
Authors: Khedr Mogibelrahman M. S. , Messaoudi Walid , Jonnalagadda Umesh S. , Abdelmotelb Ahmed M. , Glynne-Jones Peter , Hill Martyn , Khakoo Salim I. , Abu Hilal Mohammed
Published: February 2019

Ultrasonic standing wave systems have previously been used for the generation of 3D constructs for a range of cell types. In the present study, we cultured cells from the human hepatoma Huh7 cell line in a Bulk Acoustic Wave field and studied their viability, their functions, and their response to the anti-cancer drug, 5 Fluorouracil (5FU). We found that cells grown in the acoustofluidic bioreactor (AFB) expressed no reduction in viability up to 6 h of exposure compared to those cultured in a conventional 2D system. In addition, constructs created in the AFB and subsequently cultured outside of it had improved functionality including higher albumin and urea production than 2D or pellet cultures. The viability of Huh7 cells grown in the ultrasound field to 5FU anti-cancer drug was comparable to that of cells cultured in the 2D system, showing rapid diffusion into the aggregate core. We have shown that AFB formed 3D cell constructs have improved functionality over the conventional 2D monolayer and could be a promising model for anti-cancer drug testing.