bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient imines as ‘next generation’ directing groups for the catalytic functionalisation of C–H bonds in a single operation
Authors: St John-Campbell Sahra , Bull James A.
Published: May 2018

This review describes recent developments in the use of catalytic transient directing groups, through imine linkages, which in combination with transition metal catalysts provide streamlined C–H functionalisation processes.
Constructing oxygen-doped g-C3N4 nanosheets with an enlarged conductive band edge for enhanced visible-light-driven hydrogen evolution
Authors: Sun Shaodong , Li Jia , Cui Jie , Gou Xufeng , Yang Qing , Liang Shuhua , Yang Zhimao , Zhang Jianmin
Published: May 2018

Oxygen-doped g-C3N4 nanosheets with an increased conductive band edge have been synthesized via the facile H2O–H2O2-assisted hydrothermal reforming of melamine.
Fiber optic magnetic field sensor using Co doped ZnO nanorods as cladding
Authors: Narasimman S. , Balakrishnan L. , Alex Z. C.
Published: May 2018

A fiber optic magnetic field sensor based on Co doped ZnO nanorods is proposed and demonstrated. The sensor has an operating magnetic field range of 17 mT to 180 mT and shows a maximum sensitivity of ∼18% for 15 at% Co doped ZnO nanorods.
Lead removal from water – dependence on the form of carbon and surface functionalization
Authors: Kam Chun Sing , Leung Tik Lun , Liu Fangzhou , Djurišić Aleksandra B. , Xie Mao Hai , Chan Wai-Kin , Zhou Ying , Shih Kaimin
Published: May 2018

Functionalization with same functional group results in varied lead adsorption performance for different nanostructured carbon materials.
Preparation and characterization of Ag–Pd bimetallic nano-catalysts in thermosensitive microgel nano-reactor
Authors: Zhang Tao , Li Li , Ye Zhishuang , Yang Qingsong , Tian Yuchuan , Guo Xuhong
Published: May 2018

Thermosensitive microgels with PS core and cross-linked PNIPA shell were synthesized as nano-reactor to prepare Ag–Pd bimetallic nanoparticles.
The pH dependent reactions of graphene oxide with small molecule thiols
Authors: de Leon Al , Mellon Michael , Mangadlao Joey , Advincula Rigoberto , Pentzer Emily
Published: May 2018

Graphene oxide (GO), a heterogenous 2D carbon-based material, is functionalized or reduced with ethane thiol depending on solution pH.
Mechanically triggered reversible stepwise tricolor switching and thermochromism of anthracene-o-carborane dyad
Authors: Wu Xueyan , Guo Jixi , Cao Yali , Zhao Jianzhang , Jia Wei , Chen Yi , Jia Dianzeng
Published: May 2018

A novel single organic molecule–carborane conjugate, CAN, was synthesized in a high yield via a modified nickel-catalyzed cross-coupling reaction incorporating an anthracene unit and an o-carborane moiety.
Field-induced dipolar attraction between like-charged colloids
Authors: Shih Chunyu , Molina John J. , Yamamoto Ryoichi
Published: May 2018

The field induced anisotropic interactions between like-charged colloidal particles is studied using direct numerical simulations, where the polarization of the electric double layer is explicitly computed under external AC electric fields.
Thermal stability and miscibility of co-evaporated methyl ammonium lead halide (MAPbX3, X = I, Br, Cl) thin films analysed by in situ X-ray diffraction
Authors: Pistor Paul , Burwig Thomas , Brzuska Carlo , Weber Björn , Fränzel Wolfgang
Published: May 2018

We present the identification of crystalline phases by in situ X-ray diffraction during growth and monitor the phase evolution during subsequent thermal treatment of CH3NH3PbX3 (X = I, Br, Cl) perovskite thin films.
Carboxyl-functionalized ionic liquids: synthesis, characterization and synergy with rare-earth ions
Authors: Souza Ramos Talita Jordanna de , Berton Guilherme Henrique , Cassol Tania Maria , Júnior Severino Alves
Published: May 2018

Herein, we describe for the first time room temperature ionic liquids (RTILs) and imidazole-based cations with appended carboxylic acids as terminals, which are directly derived from the anhydrides.
Oligothiophene quinoids containing a benzo[c]thiophene unit for the stabilization of the quinoidal electronic structure
Authors: Yamamoto Keitaro , Ie Yutaka , Nitani Masashi , Tohnai Norimitsu , Kakiuchi Fumitoshi , Zhang Ke , Pisula Wojciech , Asadi Kamal , Blom Paul W. M. , Aso Yoshio
Published: May 2018

Bis(dicyanomethylene)-substituted quinoidal π-conjugated systems containing a benzo[c]thiophene unit have been investigated for application as n-type semiconductors.
Two‐stage load‐scheduling model for the incentive‐based demand response of industrial users considering load aggregators
Authors: Zhang Jingjing , Zhang Peng , Wu Hongbin , Qi Xianjun , Yang Shihai , Li Zhixin
Published: May 2018

The demand response (DR) resources provided by modern industrial users tend to be diversified because of the popularisation of renewable energy. In this context, for the problem of satisfaction and uncertainty in the DR, a load‐scheduling model considering load aggregators (LAs) is presented. In the multi‐level DR scheduling system, the users and aggregator simultaneously participate in the decision; thus, the proposed methodology is a two‐stage optimisation process. The first‐stage optimisation considers the load interruption strategies of complex industrial processes, where a multi‐objective optimisation model is established to coordinate the user benefits and satisfaction. This model is solved by non‐dominated sorting genetic algorithm‐II (NSGA‐II) and the entropy weight double‐base point method to obtain the optional interruptible load (IL) contracts for production processes. The second‐stage optimisation maximises the economic returns of the LA considering the uncertainty of the resource's response, where chance‐constraint programming is applied to solve the problem and select the appropriate IL contract. The effectiveness of the proposed methodology is examined according to the actual industrial production process. The multi‐objective coordination effect of production load‐scheduling is shown in an example. Finally, the effects of joint resource scheduling and different confidence levels on the profit of the aggregator are analysed.
Proactive cache replacement technique for mobile networks based on genetic programming
Authors: Darwish Saad M. , El‐Zoghabi Adel , El‐Shnawy Amr G.
Published: May 2018

In the mobile environment, the movement of users, disconnected modes, many data updates, power battery consumption, limited cache size, and limited bandwidth impose significant challenges to information access. Caching is considered one of the most important concepts to deal with these challenges. There are two general topics related to the client cache policy: cache invalidation method keeps data in the cache up to date; and cache replacement method chooses the cached item(s) which should be deleted from the cache when the cache is full. The aim of this work is to propose a new technique for cache replacement in a mobile database that takes into consideration the impact of invalidation time for enhancing data availability in the mobile environment by using genetic programming. In this case, each client collects information for every cached item in the cache like access probability, cached document size, validation time and uses these factors in a fitness function to determine cached items that will be removed from the cache. The experiments were performed using Network Simulator 2 to evaluate the effectiveness of the proposed approach, and the results are compared with the existing cache replacement algorithms. It is concluded that the proposed approach performs significantly better than other approaches.
Packet collision analysis when heterogeneous unlicensed IoT technologies coexist
Authors: Ferré Guillaume , Simon Eric Pierre
Published: May 2018

This study deals with the impact of unlicensed Internet of Things (IoT) network coexistence in terms of packet collision. The classical packet collision studies based on the Poisson distributed process generally assume homogeneous networks with packets of equal lengths. The authors propose a new approach which can be applied to a more general context including heterogeneous networks and different packet lengths. The proposed approach is based on modelling the vulnerable period and the packet length as uniform random variables. Then, the two main IoT networks considered in unlicensed spectrum, LoRa and Sigfox, are being investigated in more detail. For these two networks, closed‐form analytical formulas for the intra‐and inter‐network probability of packet collisions between nodes are provided and confirmed by simulations results. For this context, it is also shown that the ultra‐narrow band feature of Sigfox is rather a drawback than an advantage from the collision point of view. To enhance the probability of collision, some possible evolutions of the Sigfox physical layer are finally suggested.
Infrared outbursts as potential tracers of common-envelope events in high-mass X-ray binary formation
Authors: Oskinova Lidia M. , Bulik Tomasz , Gómez-Morán Ada Nebot
Published: May 2018

Context. Classic massive binary evolutionary scenarios predict that a transitional common-envelope (CE) phase could be preceded as well as succeeded by the evolutionary stage when a binary consists of a compact object and a massive star, that is, a high-mass X-ray binary (HMXB). The observational manifestations of common envelope are poorly constrained. We speculate that its ejection might be observed in some cases as a transient event at mid-infrared (IR) wavelengths.

Aims. We estimate the expected numbers of CE ejection events and HMXBs per star formation unit rate, and compare these theoretical estimates with observations.

Methods. We compiled a list of 85 mid-IR transients of uncertain nature detected by the Spitzer Infrared Intensive Transients Survey and searched for their associations with X-ray, optical, and UV sources.

Results. Confirming our theoretical estimates, we find that only one potential HMXB may be plausibly associated with an IR-transient and tentatively propose that X-ray source NGC 4490-X40 could be a precursor to the SPIRITS 16az event. Among other interesting sources, we suggest that the supernova remnant candidate [BWL2012] 063 might be associated with SPIRITS 16ajc. We also find that two SPIRITS events are likely associated with novae, and seven have potential optical counterparts.

Conclusions. The massive binary evolutionary scenarios that involve CE events do not contradict currently available observations of IR transients and HMXBs in star-forming galaxies.
Study on abnormal SEM contrast image of gold nanorods through Monte Carlo method
Authors: Zhang Peng
Published: May 2018

Because the particular photo-electricity of gold nanorods (Au NRs) presents a different characteristic than other types of Au nano-materials with various shapes, it has attracted much attention recently. Accurate measurement for aspect ratios does provide very high value on the optical property of Au NRs. Monte Carlo (MC) simulation is thought as the most accurate tool to perform size measurement through extracting structure parameters from the simulated scanning electron microscopy (SEM) image which best matches the experimental one. However, it has already been observed that the contrast of two ends of Au NRs in the experimental SEM image is brighter than that of middle part, which cannot be obtained by the conventional MC simulation approach. This phenomenon seriously affects the accuracy of size measurement for Au NRs. Therefore, in this article, a MC study was exerted on the frequently observed abnormal contrast of Au NRs. It was found that the cetyltrimethylammonium bromide (CTAB) which covers around the Au NRs indeed can alter the contrast of Au NRs comparing on that without CTAB covering. However, secondary electrons (SEs) emitting from CTAB is not the contributor for the abnormal brightness at two ends of NRs. The analysis reveals that the CTAB which covers around the Au NRs isolates Au NRs from the substrate, leading to charges accumulated in the body of Au NRs. The surface potential of Au NRs which produced by deposited charges presents a positive value and the potential value of the middle region is higher than that of both ends. Therefore, the SEs emitted from the middle region will be more easily attracted back to the surface than that emitted from both ends. As a consequence, the image contrast in the middle region of Au NRs is lower than that at both ends.
Occupational health and safety in the Moroccan construction sites: preliminary diagnosis
Authors: Tarik Bakeli , Adil Hafidi Alaoui
Published: May 2018

Managing occupational health and safety on Moroccan construction sector represents the first step for projects' success. In fact, by avoiding accidents, all the related direct and indirect costs and delays can be prevented. That leads to an important question always asked by any project manager: what are the factors responsible for accidents? How can they be avoided? Through this research, the aim is to go through these questions, to contribute in occupational health and safety principles understanding, to identify construction accidentology and risk management opportunities and to approach the case of Moroccan construction sites by an accurate diagnosis. The approach is to make researchers, managers, stakeholders and deciders aware about the criticality of construction sites health and safety situation. And, to do the first step for a scientific research project in relation with health and safety in the Moroccan construction sector. For this, the paper will study the related state of art namely about construction sites accidents causation, and will focus on Reason's ‘Swiss cheese’ model and its utilization for Moroccan construction sites health and safety diagnosis. The research will end with an estimation of an accidents fatality rate in the Moroccan construction sector and a benchmarking with the international rates. Finally, conclusions will be presented about the necessity of Occupational Health and Safety Management System (OHSMS) implementation, which shall cover all risk levels, and insure, at the same time, that the necessary defenses against accidents are on place.
Power Supply Redundancy Design of Aircraft's Electric Braking Electro-Mechanical Actuation System
Authors: Xiangli Kang , Ma Ruiqing
Published: May 2018

In this paper, a power source redundancy-optimization approach for aircraft electrical brake electromechanical actuation system was proposed. The PWM plus phase-shift (PPS) control method was introduced in Dual active half bridge, which limited the amplitude of transform's leakage inductance current, thus expanding the fluctuation range of input voltage. Then, the voltage gain formula was deduced. By analyzing the leakage current under different phase shift in one period, the average power and root-mean-square (RMS) value of leakage current can be compared. Then, the optimum modulation range of phase shift can be obtained. By analyzing the soft-switching operation in this range, all switches can realize zero-voltage-switching (ZVS). To ensure the output voltage stability and voltage balance across the leakage inductance, a closed loop control method is designed. Finally, a prototype of 28V/270V-1kW was built to verify the theoretical analysis and calculation.
Effect of High Speed Milling Process Parameters on the Milling Force and Surface Topography of AM50A Magnesium Alloy
Authors: Zhang Hongji , Ge Yuanyuan , Tang Hong , Shi Yaoyao , Li Zengsheng
Published: May 2018

Within the scope of high speed milling process parameters, analyzed and discussed the effects of spindle speed, feed rate, milling depth and milling width on milling forces in the process of high speed milling of AM50A magnesium alloy. At the same time, the influence of milling parameters on the surface roughness of AM50A magnesium alloy has been revealed by means of the measurement of surface roughness and surface micro topography. High speed milling experiments of AM50A magnesium alloy were carried out by factorial design. Form the analysis of experimental results, The milling parameters, which have significant influence on milling force in high speed milling of AM50A magnesium alloy, are milling depth, milling width and feed speed, and the nonlinear characteristics of milling force and milling parameters. The milling force decreases with the increase of spindle in the given mill parameters. For the effects of milling parameters on surface quality of the performance, in the milling depth and feeding speed under certain conditions with the spindle speed increases the surface quality of AM50A magnesium alloy becomes better with the feed speed increases the surface quality becomes poor. When the spindle speed is greater than 12000r/min, the milling depth is less than 0.2mm, and the feed speed is less than 400mm/min, the milling surface quality can be obtained easily.
Spatial Differencing Reconstruction Based Low-Angle DOA Estimation with MIMO Radar
Authors: Zhang Qin , Zhang Linrang , Shi Junpeng , Zhou Yannian , Liu Yaning
Published: May 2018

Due to the multipath effect, the direction of arrival (DOA) estimation performance for low-angle targets decreases greatly. To overcome this problem, this paper proposes a spatial differencing reconstruction based DOA estimation algorithm by using the received signal model of multiple input multiple output (MIMO) radar. Combining with the spatial diversity of MIMO radar, the proposed method can first use the multipath echo power to select the best signal. Then, a spatial differencing based iterative scheme is developed to reduce the effect of additive noise, resulting in a better estimation performance for low-angle targets. Simulation results show that the proposed method has better advantages in suppressing noise and improving estimation accuracy.
Zystische Fibrose – gibt es Aussicht auf Heilung?
Authors: Krüger Linn
Published: May 2018

Die zystische Fibrose (Cystic Fibrosis – CF), auch Mukoviszidose genannt, ist die häufigste angeborene Stoffwechselerkrankung in Mitteleuropa. Erstmals wurde sie
1936 vom Kinderarzt Guido Fanconi aus Zürich beschrieben. Die Lebensqualität und die mittlere Überlebensrate der Betroffenen sind in den letzten 20 Jahren durch
verbesserte diagnostische und therapeutische Strategien kontinuierlich angestiegen. Linn Krüger stellt das Krankheitsbild, dessen Diagnostik und
Therapiemöglichkeiten vor.
Effektivität von Übungsinterventionen bei der Behandlung unspezifischer Nackenschmerzen
Authors: Kull Philipp , Reichert Bernhard
Published: May 2018

Unspezifische Nackenschmerzen stellen eine der häufigsten Problematiken am menschlichen Bewegungsapparat dar. Daher ist ihre effiziente und effektive Behandlung
in der Physiotherapie von großer Bedeutung.

Ziel dieser Arbeit war es, anhand einer Literaturanalyse die Wirksamkeit von therapeutischen Übungs- und Trainingsinterventionen in den Bereichen Schmerz und
Funktion auszuwerten, um so möglicherweise die physiotherapeutische Behandlung zu optimieren.

In allen 8 ausgewerteten Studien verbesserten aktive Interventionen die Funktion und reduzierten unspezifische Nackenschmerzen. Besonders gute Werte erreichten
hierbei passive Dehnübungen bestimmter Nackenmuskeln in einem Zeitraum von 6 Wochen so non-specific wie ein Kraftausdauertraining der Nacken- und
Schultermuskulatur mit externen Widerständen über mindestens 12 Wochen.

Die methodische Qualität der einzelnen Arbeiten bewegte sich zwischen 6/11 und 8/11 Punkten auf der PEDro-Skala. Aufgrund der Qualität und Quantität der Studien
kann anhand der Ergebnisse dieser Literaturanalyse keine exakte Handlungs- und Dosierungsempfehlung gegeben werden. Mit hoher Wahrscheinlichkeit ist jedoch
davon auszugehen, dass therapeutische Übungs- und Trainingsinterventionen bei Patienten mit unspezifischen Nackenschmerzen sehr gute Ergebnisse erzielen.
Rehabilitation nach traumatischen Frakturen der Brust- und Lendenwirbelsäule
Authors: Bork Hartmut , Simmel Stefan , Böhle Eckhardt , Ernst Ulrich , Fischer Klaus , Fromm Bernd , Glaesener Jean-Jacques , Greitemann Bernhard , Krause P. , Panning S. , Pullwitt V. , Schmidt J. , Veihelmann Andreas , Vogt Lutz
Published: May 2018

Die Übersichtsarbeit gibt auf der Grundlage der überarbeiteten S2k-Leitlinie Rehabilitation nach traumatischen Frakturen der Brust- und Lendenwirbelsäule ohne neurologische Ausfälle einen aktuellen Überblick über eine zielgerichtete Rehabilitation von Patienten mit stabilen bzw. operativ stabil versorgten traumatischen Frakturen an der Brust- und Lendenwirbelsäule. Um eine schnelle soziale und berufliche Wiedereingliederung zu erzielen, soll die Rehabilitation unter Berücksichtigung der Kriterien für eine ambulante/stationäre Rehabilitation hierbei so früh wie möglich eingeleitet werden. Die Rehabilitations- und Therapieziele sollten sich am biopsychosozialen ICF-Modell der WHO orientieren und müssen vom Team mit dem Patienten abgestimmt werden. Übergeordnetes Rehabilitationsziel ist die Besserung der funktionalen Gesundheit und Wiederherstellung der ursprünglichen Teilhabefähigkeiten. Aufgrund des individuellen Behandlungsfortschrittes können sich Zielsetzungen während der Rehabilitation auch verändern. Schmerztherapeutische Interventionen haben sich an den jeweiligen individuellen Bedürfnissen zu orientieren. Sie sollten multimodal ausgerichtet sein, wobei psychische Kontextfaktoren (Depressivität, Angst, beruflicher Disstress, passives Schmerzverhalten sowie schmerzbezogene Kognitionen, posttraumatische Belastungsstörung) im Rahmen der Rehabilitation frühzeitig erfasst und durch psychologisch fundierte bzw. psychotherapeutische Interventionen behandelt werden sollten, da sie zu einer Chronifizierung von Schmerzen beitragen. Der Einsatz einer frühen funktionell-bewegungsorientierten Therapie wird in der Leitlinie positiv bewertet. Bewegungstherapie wird in der Krankengymnastik, Sporttherapie und einigen Verfahren der Ergotherapie angewandt. Ziel ist u. a. auch die Vermittlung gesundheitsorientierter Verhaltensweisen. Eine orthetische Versorgung von Frakturen der Brust- und Lendenwirbelsäule ist bei stabilen Situationen gemäß der Leitlinie i. d. R. nicht notwendig. Um den Behandlungserfolg einer Rehabilitation zu sichern, ist es sinnvoll, bereits während der rehabilitativen Phase Weichen für die weitere Nachbehandlung zu stellen und vor allem erwerbstätige Patienten in gezielte ambulante Nachsorgeprogramme zu vermitteln.
Safety Model for the Introduction of Robotic Surgery in Gynecology
Authors: Gomes Mariano Tamura Vieira , Costa Porto Beatriz Taliberti da , Parise Filho Jose Pedro , Vasconcelos Ana Luiz , Bottura Bruna Fernanda , Marques Renato Moretti
Published: May 2018

Objective To analyze the perioperative results and safety of performing gynecological surgeries using robot-assisted laparoscopy during implementation of the technique in a community hospital over a 6-year period.

Methods This was a retrospective observational study in which the medical records of 274 patients who underwent robotic surgery from September 2008 to December 2014 were analyzed. We evaluated age, body mass index (BMI), diagnosis, procedures performed, American Society of Anesthesiologists (ASA) classification, the presence of a proctor (experienced surgeon with at least 20 robotic cases), operative time, transfusion rate, perioperative complications, conversion rate, length of stay, referral to the intensive care unit (ICU), and mortality. We compared transfusion rate, perioperative complications and conversion rate between procedures performed by experienced and beginner robotic surgeons assisted by an experienced proctor.

Results During the observed period, 3 experienced robotic surgeons performed 187 surgeries, while 87 surgeries were performed by 20 less experienced teams, always with the assistance of a proctor. The median patient age was 38 years, and the median BMI was 23.3 kg/m2. The most frequent diagnosis was endometriosis (57%) and the great majority of the patients were classified as ASA I or ASA II (99.6%). The median operative time was 225 minutes, and the median length of stay was 2 days. We observed a 5.8% transfusion rate, 0.8% rate of perioperative complications, 1.1% conversion rate to laparoscopy or laparotomy, no patients referred to ICU, and no deaths. There were no differences in transfusion, complications and conversion rates between experienced robotic surgeons and beginner robotic surgeons assisted by an experienced proctor.

Conclusion In our casuistic, robot-assisted laparoscopy demonstrated to be a safe technique for gynecological surgeries, and the presence of an experienced proctor was considered a highlight in the safety model adopted for the introduction of the robotic gynecological surgery in a high-volume hospital and, mainly, for its extension among several surgical teams, assuring patient safety.
Translation and Cultural Adaptation of the Short-Form Food Frequency Questionnaire for Pregnancy into Brazilian Portuguese
Authors: Kasawara Karina Tamy , Paulino Daiane S. M. , Bgeginski Roberta , Cleghorn Chistine L. , Mottola Michelle F. , Surita Fernanda Garanhani
Published: May 2018

Objective To translate and culturally adapt the short-form Food Frequency Questionnaire (SFFFQ) for pregnant women, which contains 24 questions, into Brazilian Portuguese.

Methods Description of the process of translation and cultural adaptation of the SFFFQ into Brazilian Portuguese. The present study followed the recommendation of the International Society for Pharmacoeconomics and Outcomes Research for translation and cultural adaptation with the following steps: 1) preparation; 2) first translation; 3) reconciliation; 4) back translation; 5) revision of back translation; 6) harmonization; 7) cognitive debriefing; 8) revision of debriefing results; 9) syntax and orthographic revision; and 10) final report. Five obstetricians, five dietitians and five pregnant women were interviewed to contribute with the language content of the SFFFQ.

Results Few changes were made to the SFFFQ compared with the original version. These changes were discussed with the research team, and differences in language were adapted to suit all regions of Brazil.

Conclusion The SFFFQ translated to Brazilian Portuguese can now be validated for use in the Brazilian population.
Methodology for the investigation of ignition near hot surfaces in a high-pressure shock tube
Authors: Niegemann P. , Fikri M. , Wlokas I. , Röder M. , Schulz C.
Published: May 2018

Autoignition of fuel/air mixtures is a determining process in internal combustion engines. Ignition can start either homogeneously in the gas phase after compression or in the vicinity of hot surfaces. While ignition properties of commercial fuels are conventionally described by a single quantity (octane number), it is known that some fuels have a varying propensity to the two processes. We present a new experimental concept that generates well-controlled temperature inhomogeneities in the shock-heated gases of a high-pressure shock tube. A shock-heated reactive mixture is brought into contact with a heated silicon nitride ceramic glow plug. The glow-plug temperature can be set up to 1200 K, higher than the post-reflected-shock gas temperatures (650–1050 K). High-repetition-rate chemiluminescence imaging is used to localize the onset of ignition in the vicinity of the hot surface. In experiments with ethanol, the results show that in most cases under shock-heated conditions, the ignition begins inhomogeneously in the vicinity of the glow plug and is favored because of the high wall temperature. Additionally, the interaction of geometry, external heating, and gas-dynamic effects was investigated by numerical simulations of the shock wave in a non-reactive flow.
Multi-resolution polymer Brownian dynamics with hydrodynamic interactions
Authors: Rolls Edward , Erban Radek
Published: May 2018

A polymer model given in terms of beads, interacting through Hookean springs and hydrodynamic forces, is studied. A Brownian dynamics description of this bead-spring polymer model is extended to multiple resolutions. Using this multiscale approach, a modeller can efficiently look at different regions of the polymer in different spatial and temporal resolutions with scalings given for the number of beads, statistical segment length, and bead radius in order to maintain macro-scale properties of the polymer filament. The Boltzmann distribution of a Gaussian chain for differing statistical segment lengths gives a diffusive displacement equation for the multi-resolution model with a mobility tensor for different bead sizes. Using the pre-averaging approximation, the translational diffusion coefficient is obtained as a function of the inverse of a matrix and then in closed form in the long-chain limit. This is then confirmed with numerical experiments.
Frequency adaptive metadynamics for the calculation of rare-event kinetics
Authors: Wang Yong , Valsson Omar , Tiwary Pratyush , Parrinello Michele , Lindorff-Larsen Kresten
Published: May 2018

The ability to predict accurate thermodynamic and kinetic properties in biomolecular systems is of both scientific and practical utility. While both remain very difficult, predictions of kinetics are particularly difficult because rates, in contrast to free energies, depend on the route taken. For this reason, specific enhanced sampling methods are needed to calculate long-time scale kinetics. It has recently been demonstrated that it is possible to recover kinetics through the so-called “infrequent metadynamics” simulations, where the simulations are biased in a way that minimally corrupts the dynamics of moving between metastable states. This method, however, requires the bias to be added slowly, thus hampering applications to processes with only modest separations of time scales. Here we present a frequency-adaptive strategy which bridges normal and infrequent metadynamics. We show that this strategy can improve the precision and accuracy of rate calculations at fixed computational cost and should be able to extend rate calculations for much slower kinetic processes.
A path integral methodology for obtaining thermodynamic properties of nonadiabatic systems using Gaussian mixture distributions
Authors: Raymond Neil , Iouchtchenko Dmitri , Roy Pierre-Nicholas , Nooijen Marcel
Published: May 2018

We introduce a new path integral Monte Carlo method for investigating nonadiabatic systems in thermal equilibrium and demonstrate an approach to reducing stochastic error. We derive a general path integral expression for the partition function in a product basis of continuous nuclear and discrete electronic degrees of freedom without the use of any mapping schemes. We separate our Hamiltonian into a harmonic portion and a coupling portion; the partition function can then be calculated as the product of a Monte Carlo estimator (of the coupling contribution to the partition function) and a normalization factor (that is evaluated analytically). A Gaussian mixture model is used to evaluate the Monte Carlo estimator in a computationally efficient manner. Using two model systems, we demonstrate our approach to reduce the stochastic error associated with the Monte Carlo estimator. We show that the selection of the harmonic oscillators comprising the sampling distribution directly affects the efficiency of the method. Our results demonstrate that our path integral Monte Carlo method’s deviation from exact Trotter calculations is dominated by the choice of the sampling distribution. By improving the sampling distribution, we can drastically reduce the stochastic error leading to lower computational cost.
Note: A contraction channel design for planar shock wave enhancement
Authors: Zhan Dongwen , Li Zhufei , Yang Jianting , Zhu Yujian , Yang Jiming
Published: May 2018

A two-dimensional contraction channel with a theoretically designed concave-oblique-convex wall profile is proposed to obtain a smooth planar-to-planar shock transition with shock intensity amplification that can easily overcome the limitations of a conventional shock tube. The concave segment of the wall profile, which is carefully determined based on shock dynamics theory, transforms the shock shape from an initial plane into a cylindrical arc. Then the level of shock enhancement is mainly contributed by the cylindrical shock convergence within the following oblique segment, after which the cylindrical shock is again “bent” back into a planar shape through the third section of the shock dynamically designed convex segment. A typical example is presented with a combination of experimental and numerical methods, where the shape of transmitted shock is almost planar and the post-shock flow has no obvious reflected waves. A quantitative investigation shows that the difference between the designed and experimental transmitted shock intensities is merely 1.4%. Thanks to its advantage that the wall profile design is insensitive to initial shock strength variations and high-temperature gas effects, this method exhibits attractive potential as an efficient approach to a certain, controllable, extreme condition of a strong shock wave with relatively uniform flow behind.
Investigation of the distribution of localised and extended states in amorphous MoOx
Authors: Dizayee Wala , Ying Minju , Griffin Jonathan , Alqahtani Mohammed S. , Buckley Alastair , Fox A. Mark , Gehring Gillian A.
Published: May 2018

Amorphous films of MoOx have both structural disorder and also chemical disorder for x<3. We have shown that this disorder can introduce localised states in thin films and have shown that the existence of localised states can be deduced from the XPS data that identifies the relevant occupations of different ionisation states of the Mo ions. This effect, which depends on both the oxygen concentration and the method of fabrication, is more important than electron-electron interactions in producing the observed localisation. We have also shown that magneto-optical dichroism is also a powerful technique to determine the energy distribution of localised and delocalised states.
Benchmarking the communication fidelity of biomolecular signaling cascades featuring pseudo-one-dimensional transport
Authors: Rana Pratip , Pilkiewicz Kevin R. , Mayo Michael L. , Ghosh Preetam
Published: May 2018

Synthetic biologists endeavor to predict how the increasing complexity of multi-step signaling cascades impacts the fidelity of molecular signaling, whereby information about the cellular state is often transmitted with proteins that diffuse by a pseudo-one-dimensional stochastic process. This begs the question of how the cell leverages passive transport mechanisms to distinguish informative signals from the intrinsic noise of diffusion. We address this problem by using a one-dimensional drift-diffusion model to derive an approximate lower bound on the degree of facilitation needed to achieve single-bit informational efficiency in signaling cascades as a function of their length. Within the assumptions of our model, we find that a universal curve of the Shannon-Hartley form describes the information transmitted by a signaling chain of arbitrary length and depends upon only a small number of physically measurable parameters. This enables our model to be used in conjunction with experimental measurements to aid in the selective design of biomolecular systems that can overcome noise to function reliably, even at the single-cell level.
Epitaxial growth of high quality InP on Si substrates: The role of InAs/InP quantum dots as effective dislocation filters
Authors: Shi Bei , Li Qiang , Lau Kei May
Published: May 2018

Monolithic integration of InP on a Si platform ideally facilitates on-chip light sources in silicon photonic applications. In addition to the well-developed hybrid bonding techniques, the direct epitaxy method is spawning as a more strategic and potentially cost-effective approach to monolithically integrate InP-based telecom lasers. To minimize the unwanted defects within the InP crystal, we explore multiple InAs/InP quantum dots as dislocation filters. The high quality InP buffer is thus obtained, and the dislocation filtering effects of the quantum dots are directly examined via both plan-view and cross-sectional transmission electron microscopy, along with room-temperature photoluminescence. The defect density on the InP surface was reduced to 3 × 108/cm2, providing an improved optical property of active photonic devices on Si substrates. This work offers a novel solution to advance large-scale integration of InP on Si, which is beneficial to silicon-based long-wavelength lasers in telecommunications.
Numerical modelling of inverse wire array Z-pinch magnetic reconnection
Authors: Duan Shu-Chao , Kan Ming-Xian , Xiao Bo , Xu Qiang , Yang Long , Wang Gang-Hua , Huang Xian-Bin , Xie Wei-Ping
Published: May 2018

In this paper, a relaxation magnetohydrodynamic model is used to study magnetic reconnection phenomena in pulsed-power-driven Z-pinch inverse wire arrays. We focus on certain characteristics of two distinct modes that differ by resistivity. A magnetic field alignment that is both anti-parallel and open is created in high-resistivity mode. This produces a pronounced slow/standing shock wave and outflows can be accelerated to super-magnetosonic velocities. In low-resistivity mode, the entire magnetic field is closed and there is no pronounced slow/standing shock wave. The outflow velocity along the neutral line is accelerated to magnetosonic velocities between the two magnetic islands, but slows afterwards. It is difficult to achieve steady or quasi-steady magnetic reconnection in pulsed-power-driven Z-pinch inverse wire arrays.
Analytical solution and numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe
Authors: Cai Haibing , Xu Liuxun , Yang Yugui , Li Longqi
Published: May 2018

Artificial liquid nitrogen freezing technology is widely used in urban underground engineering due to its technical advantages, such as simple freezing system, high freezing speed, low freezing temperature, high strength of frozen soil, and absence of pollution. However, technical difficulties such as undefined range of liquid nitrogen freezing and thickness of frozen wall gradually emerge during the application process. Thus, the analytical solution of the freezing-temperature field of a single pipe is established considering the freezing temperature of soil and the constant temperature of freezing pipe wall. This solution is then applied in a liquid nitrogen freezing project. Calculation results show that the radius of freezing front of liquid nitrogen is proportional to the square root of freezing time. The radius of the freezing front also decreases with decreased the freezing temperature, and the temperature gradient of soil decreases with increased distance from the freezing pipe. The radius of cooling zone in the unfrozen area is approximately four times the radius of the freezing front. Meanwhile, the numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe is conducted using the Abaqus finite-element program. Results show that the numerical simulation of soil temperature distribution law well agrees with the analytical solution, further verifies the reliability of the established analytical solution of the liquid nitrogen freezing-temperature field of a single pipe.
Acoustic properties and density of polyurea at pressure up to 13.5 GPa through Brillouin scattering spectroscopy
Authors: Ransom T. C. , Ahart Muhtar , Hemley Russell J. , Roland C. M.
Published: May 2018

Brillouin scattering was performed on an elastomeric polyurea, an important technological polymer. Being widely used for impact modification, of particular interest is its response to extreme pressure conditions. We applied pressures up to 13.5 GPa using a diamond anvil cell and measured the longitudinal and transverse sound velocities via Brillouin light scattering. From these data, the equation of state, the elastic moduli, and Poisson's ratio were obtained. By comparison with previous dilatometry measurements up to 1 GPa, we show how viscoelastic effects can be accounted for in order to obtain an accurate equation of state. Because of the extreme strain-rate hardening of vitrifying polyurea, the property changes associated with its solidification are more subtle in the high frequency Brillouin data than observed in conventional mechanical testing and dilatometry.
“Insanity is from home”
Authors: Amfo Nana Aba Appiah , Houphouet Ekua Essumanma , Dordoye Eugene K. , Thompson Rachel
Published: May 2018

This paper examines selected expressions relating to the articulation of mental health challenges in three Akan speaking communities in Ghana, in the context of considering that language is reflective of human thought, and that human cultural practices and behavior emanate from people’s underlying appreciation of particular issues. Expressions of mental health challenges were extracted from a total of 37 one-on-one interviews and 12 focus group discussions. We note that the expressions used fall into 3 categories: idioms and proverbs, non-figurative language and code mixed utterances. Overall, indirection permeates all the categories. Furthermore, our observation is that the expressions provide an indication of the manifestations and perceived causes of the illnesses, which are familial, spiritual or biomedical. There is a strong tendency towards an expectation of communal support for the mentally ill. An appreciation of the languages and cultures of local communities provides the basis for appropriate diagnosis, effective management of mental illness and efficient public health education.
An extension of positivity for integrals of Bessel functions and Buhmann’s radial basis functions
Authors: Cho Yong-Kum , Chung Seok-Young , Yun Hera
Published: May 2018

As to the Bessel integrals of type
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="integral Subscript 0 Superscript x Baseline left-parenthesis x Superscript mu Baseline minus t Superscript mu Baseline right-parenthesis Superscript lamda Baseline t Superscript alpha Baseline upper J Subscript beta Baseline left-parenthesis t right-parenthesis d t left-parenthesis x greater-than 0 right-parenthesis comma">

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\begin{equation*} \int _0^x \left (x^\mu -t^\mu \right )^\lambda t^\alpha J_\beta (t)dt\qquad (x>0), \end{equation*}

we improve known positivity results by making use of new positivity criteria for

1

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and

2

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generalized hypergeometric functions. As an application, we extend Buhmann’s class of compactly supported radial basis functions.
PyCoTools: a Python toolbox for COPASI
Authors: Welsh Ciaran M , Fullard Nicola , Proctor Carole J , Martinez-Guimera Alvaro , Isfort Robert J , Bascom Charles C , Tasseff Ryan , Przyborski Stefan A , Shanley Daryl P
Published: May 2018

Motivation

COPASI is an open source software package for constructing, simulating and analyzing dynamic models of biochemical networks. COPASI is primarily intended to be used with a graphical user interface but often it is desirable to be able to access COPASI features programmatically, with a high level interface.

Results

PyCoTools is a Python package aimed at providing a high level interface to COPASI tasks with an emphasis on model calibration. PyCoTools enables the construction of COPASI models and the execution of a subset of COPASI tasks including time courses, parameter scans and parameter estimations. Additional ‘composite’ tasks which use COPASI tasks as building blocks are available for increasing parameter estimation throughput, performing identifiability analysis and performing model selection. PyCoTools supports exploratory data analysis on parameter estimation data to assist with troubleshooting model calibrations. We demonstrate PyCoTools by posing a model selection problem designed to show case PyCoTools within a realistic scenario. The aim of the model selection problem is to test the feasibility of three alternative hypotheses in explaining experimental data derived from neonatal dermal fibroblasts in response to TGF-β over time. PyCoTools is used to critically analyze the parameter estimations and propose strategies for model improvement.

Availability and implementation

PyCoTools can be downloaded from the Python Package Index (PyPI) using the command ’pip install pycotools’ or directly from GitHub (https://github.com/CiaranWelsh/pycotools). Documentation at http://pycotools.readthedocs.io.

Supplementary information

Supplementary data are available at Bioinformatics online.
Inflammatory Bowel Disease Telemedicine Clinical Trial: Impact of Educational Text Messages on Disease-Specific Knowledge Over 1 Year
Authors: Abutaleb Ameer , Buchwald Andrea , Chudy-Onwugaje Kenechukwu , Langenberg Patricia , Regueiro Miguel , Schwartz David A , Tracy J Kathleen , Ghazi Leyla , Patil Seema A , Quezada Sandra M , Russman Katharine M , Quinn Charlene C , Jambaulikar Guruprasad , Beaulieu Dawn B , Horst Sara , Cross Raymond K
Published: May 2018

Background

Effective treatments are available for patients with inflammatory bowel disease (IBD); however, suboptimal outcomes occur and are often linked to patients’ limited disease knowledge. The aim of this analysis was to determine if delivery of educational messages through a telemedicine system improves IBD knowledge.

Methods

TELEmedicine for Patients with IBD (TELE-IBD) was a randomized controlled trial with visits at baseline, 6 months, and 12 months; patient knowledge was a secondary aim of the study. Patients were randomized to receive TELE-IBD every other week (EOW), weekly (TELE-IBD W), or standard of care. Knowledge was assessed at each visit with the Crohn’s and Colitis Knowledge (CCKNOW) survey. The primary outcome was change in CCKNOW score over 1 year compared between the TELE-IBD and control groups.

Results

This analysis included 219 participants. Participants in the TELE-IBD arms had a greater improvement in CCKNOW score compared with standard care (TELE-IBD EOW +2.4 vs standard care +1.8, P = 0.03; TELE-IBD W +2.0 vs standard care +1.8, P = 0.35). Participants with lower baseline CCKNOW scores had a greater change in their score over time (P < 0.01). However, after adjusting for race, site, and baseline knowledge, there was no difference in CCKNOW score change between the control and telemedicine arms.

Conclusions

Telemedicine improves IBD-specific knowledge through text messaging, although the improvement is not additive with greater frequency of text messages. However, after adjustment for confounding variables, telemedicine is not superior to education given through standard visits at referral centers. Further research is needed to determine if revised systems with different modes of delivery and/or frequency of messages improve disease knowledge.