bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrodeposited nickel–graphene nanocomposite coating: effect of graphene nanoplatelet size on its microstructure and hardness
Authors: Van Hau Tran , Van Trinh Pham , Hoai Nam Nguyen Phuong , Van Tu Nguyen , Lam Vu Dinh , Phuong Doan Dinh , Minh Phan Ngoc , Thang Bui Hung
Published: June 2020

The effect of graphene nanoplatelet size on the microstructure and hardness of electrodeposited nickel–graphene nanocomposite coatings was investigated.
Solution-processed graphene oxide electrode for supercapacitors fabricated using low temperature thermal reduction
Authors: Kil Hye-Jun , Yun Kayoung , Yoo Mak-Eum , Kim Seungchul , Park Jin-Woo
Published: June 2020

We present a low temperature and solution-based fabrication process for reduced graphene oxide (rGO) electrodes for electric double layer capacitors (EDLCs).
Nickel salt of phosphomolybdic acid as a bi-functional homogeneous recyclable catalyst for base free transformation of aldehyde into ester
Authors: Patel Anjali , Patel Jay
Published: June 2020

A Ni salt of phosphomolybdic acid (NiHPMA) was synthesized, characterized and evaluated for bi-functional activityviaconversion of benzaldehyde to ethyl benzoate. The role of Mo-peroxo and Ni-oxo was confirmed by UV-visible/Raman spectroscopy.
A tumor-microenvironment-responsive nanomaterial for cancer chemo-photothermal therapy
Authors: Wang Kaiyu , Cai Zhiyuan , Fan Rong , Yang Qian , Zhu Tao , Jiang Zhongying , Ma Yuqiang
Published: June 2020

Endogenous hydrogen peroxide was utilized to control the release of agents for better tumor therapeutic effect and safety.
Arenium cation or radical cation? An insight into the cyclodehydrogenation reaction of 2-substituted binaphthyls mediated by Lewis acids
Authors: Camargo Solórzano Patricia , Baumgartner María T. , Puiatti Marcelo , Jimenez Liliana B.
Published: June 2020

Cyclodehydrogenation reactions of 2-substituted binaphthyls induced by a Lewis acid. Synthesis and theoretical studies of the reaction mechanisms.
STM apparent height measurements of molecular wires with different physical length attached on 2-D phase separated templates for evaluation of single molecular conductance
Authors: Iizuka Tomoya , Shimizu Daiki , Matsuda Kenji
Published: June 2020

Single molecular conductance of molecular wires is effectively evaluated by the combination of STM apparent height measurement and a 2-D phase separation technique.
Effect of the C-terminal amino acid of the peptide on the structure and mechanical properties of alginate–peptide hydrogels across length-scales
Authors: Ochbaum Guy , Chetrit Einat , Berkovich Ronen , Bitton Ronit
Published: June 2020

The C-terminus of peptides strongly affects the structural and mechanical properties of alginate–peptide conjugated hydrogels over several length-scales.
Hydrogen bonding and charge transport in a protic polymerized ionic liquid
Authors: Anton Arthur Markus , Frenzel Falk , Yuan Jiayin , Tress Martin , Kremer Friedrich
Published: June 2020

Hydrogen bonding and charge transport in the protic polymerized ionic liquid PAAPS are studied by combining Fourier transform infrared (FTIR) and broadband dielectric spectroscopy (BDS) in a wide temperature range from 170 to 300 K.
Molecular understanding for large deformations of soft bottlebrush polymer networks
Authors: Cai Li-Heng
Published: June 2020

We discover a new regime in which the extensibility of bottlebrush polymer networks is inversely proportional to the network stiffness.
Complex emulsions for shape control based on mass transfer and phase separation
Authors: Zhang Feng , Jiang Leilei , Zeng Changfeng , Wang Chongqing , Wang Jun , Ke Xuebin , Zhang Lixiong
Published: June 2020

Complex emulsions are used to control morphologies of multiple Janus droplets, evolving from non-engulfing to complete engulfing core/shell configuration.
Electric field assisted assembly of 1D supramolecular nanofibres for enhanced supercapacitive performance
Authors: Kundu Suman , George Subi J. , Kulkarni Giridhar U.
Published: June 2020

Supramolecular nanofibres aligned by applying an external AC electric field for enhancing the energy storage performance of a planar supercapacitor.
CO2-switchable membranes: structures, functions, and separation applications in aqueous medium
Authors: Dong Liangliang , Zhao Yue
Published: June 2020

CO2-switchable membranes represent an exciting separation technology based on gas-tunable pore sizes and surface properties.
Self-recovering dual cross-linked hydrogels based on bioorthogonal click chemistry and ionic interactions
Authors: Zhan Henan , Jiang Shanshan , Jonker Anika M. , Pijpers Imke A. B. , Löwik Dennis W. P. M.
Published: June 2020

The biocompatible, injectable and high water-swollen nature of dual cross-linked hydrogels makes them a popular candidate to imitate the extracellular matrix (ECM) for tissue engineering both in vitro and in vivo.
Two-dimensional conjugated polymer films via liquid-interface-assisted synthesis toward organic electronic devices
Authors: Liu Kejun , Wang Lihuan , Dong Renhao
Published: June 2020

Development of conjugated polymers in two dimensions via liquid-interface-assisted synthesis as active layers for use in electronic devices.
Microwave-assisted selective heating to rapidly construct a nano-cracked hollow sponge for stretch sensing
Authors: Liu Pengju , Chen Wenhua
Published: June 2020

A fast and eco-friendly method assisted by microwave (MW) selective heating is proposed to prepare an ultra-sensitive sensor.
Science is necessarily collaborative
Authors: Thomas Ben
Published: June 2020

Science is, by nature, a collaborative venture; however, a ‘closed’ culture of science has nonetheless developed. Data are often hoarded for extended periods of time, paywalls prevent access to articles and unnecessary hurdles continue to slow the rate of progress. An ‘open’ culture of science would provide the most benefit to the public, to the scientists involved and to science itself, and it is best to begin practicing open science as early as possible in your scientific career.
MEC‐enabled video streaming in device‐to‐device networks
Authors: Zhang Xuguang , Lin Huangda , Chen Mingkai , Kang Bin , Wang Lei
Published: June 2020

By offloading video streaming from the centralised cloud to the edge, mobile edge computing (MEC) servers offer new opportunities for real‐time video transmission. Deploying on the edge of users can ensure low latency transmission, however, the limited storage and computing ability cannot adapt to the currently used video transmission technologies such as video transcoding or simulcast. To solve this problem, a more flexible video transmission architecture needs to be considered. Under this motivation, the authors propose a device‐to‐device (D2D) assisted video streaming scheme, which fuses the technical advantages of MEC and scalable video coding. Specifically, they first construct a novel architecture for delay‐sensitive live video streaming services in edge‐enabled wireless heterogeneous networks named MEC‐enabled goodput‐aware (MEGA) model. Then they present a mathematical formulation for optimising the aggregation goodput performance of video traffic including both cellular and D2D links. Finally, they derive a three‐step solution based on a distributed heuristic algorithm. Numerical simulation results show that MEGA outperforms existing models in terms of goodput, end‐to‐end delay, effective loss rate, and users' quality‐of‐experience.
3D electromagnetic behaviours and discharge characteristics of superconducting flywheel energy storage system with radial‐type high‐temperature bearing
Authors: Yu Zhiqiang , Feng Wenjie , Sun Xiaoyun , Gu Zhifeng , Wen Cheng
Published: June 2020

The authors have built a 2 kW/28.5 kJ superconducting flywheel energy storage system (SFESS) with a radial‐type high‐temperature superconducting bearing (HTSB). Its 3D dynamic electromagnetic behaviours were investigated based on the H ‐method, showing the non‐uniform electromagnetic force due to unevenly distributed induced current may cause the superconducting magnet stator of the HTSB cracks. As the SFESS discharges, the amplitude and frequency of the discharge voltage decrease with speed, dropping by 55 and 58%, respectively, from the beginning phase (BP) to the middle phase (MP), by 41 and 37% from the MP to end phase. The decay rates of the discharge voltage and its fluctuation are both increased compared with the no‐load operation. During the BP to MP, the output power is higher, the power quality is better and the harmonics are less. The amplitude and frequency of radial vibration are proportional to speed, larger than that during the no‐load operation in the same case, and in the BP about 1.8 and 8.8% amplitude in the x and y directions, respectively. Its two norm is increasing by 2.6%, probably leading to the friction between the shaft and protective bearings, gradually becoming greater with speed.
Conceptual design approach of wideband fractal dielectric resonator antenna
Authors: Gangwar Kapil , Sharma Anand , Gangwar Ravi Kumar
Published: June 2020

This study explains a novel wideband curvilinear Sierpinski fractal geometry (CSFG) based cylindrical dielectric resonator antenna. CSFG provides wider bandwidth by the combination of two important concepts: (i) reduction in volume to the surface area of the complete radiating structure, which in turn reduces the Q‐factor; (ii) generation of two radiating modes inside the radiating structure HEM11δ and TM01δ. The prototype of the proposed antenna is fabricated for verifying the simulated results. Measured reflection coefficient (|S11|) shows that the proposed antenna structure operates over the frequency range 2.2–3.5 GHz with the fractional bandwidth of 45.61%. Diversified radiation pattern, i.e. monopole (due to TM01δ mode) and broadside (due to HEM11δ mode) is also an important feature of the proposed antenna structure. The antenna design is relevant for WLAN (2.5 GHz) and WiMAX (3.3 GHz) applications.
Circularly polarised microstrip line leaky‐wave antenna terminated with patch
Authors: Pan Yongsheng , Dong Yuandan
Published: June 2020

A novel gain/bandwidth enhanced leaky‐wave microstrip line antenna with circular polarisation (CP) is proposed. Different from common leaky‐wave antennas with an open, short or resistive termination, this antenna consists of a leaky‐wave rampart‐line antenna terminated with a CP patch radiator. The energy from the feeding point is first radiated by the rampart‐line antenna, while the remaining part is radiated through the CP patch element. As a result, the size of the leaky‐wave part can be reduced. The resulting size of this antenna is only 1.6 × 1.6 λ2.4G (λ2.4G is free space wavelength at 2.4 GHz). Energy loss caused by the resistive termination is avoided, so that high efficiency is achieved – higher than 85% within the whole band. By introducing slight CP centre frequency difference between the patch and rampart antenna, two CP resonances were generated and the 3 dB axial ratio (AR) bandwidth is substantially broadened. Measured AR bandwidth is 9.9% (2.30–2.54 GHz). Its − 10 dB impedance bandwidth is 2.25 GHz to higher than 3 GHz, and peak gain is 13.2 dBic. The proposed antenna has a fully used radiation aperture, achieving a favourable performance, such as wide bandwidth, high gain, and a relatively stable (less tilted) boresight radiation.
Design of a wideband substrate integrated waveguide antenna with high‐gain employing two bow‐tie‐shaped slots
Authors: Yang Ming , Zhou Jinzhi
Published: June 2020

In this work, a compact antenna employing the substrate integrated waveguide (SIW) technology is investigated to achieve the characteristics of wideband and high gain. A pair of novel elliptical patches, which operate as an electric dipole, are loaded on the upper surface of the antenna. Two bow‐tie‐shaped slots are etched in parallel on the upper surface of SIW to obtain the features of magneto dipole and wideband. Combined with the low profile character of the SIW, the low cost of printed circuit board technology and the broadband characteristic of magneto‐electric (ME) dipole, a 1 × 8 SIW ME‐dipole antenna array is proposed and fabricated. The experimental result of the proposed prototype shows that the 10 dB impedance bandwidth is 42.3% from 19.4 to 29.8 GHz, which is basically consistent with the simulated result. Moreover, the antenna gain up to 14.6 dBi and the radiation efficiency higher than 82.6% are also obtained during the experiment. In the whole resonance band, excellent directional radiation, cross‐polarisation level <−25 dB and gain fluctuation <2.7 dB all suggest that the array can be applied to a fifth‐generation wireless network.
RBFNN: a radial basis function neural network model for detecting and mitigating the cache pollution attacks in named data networking
Authors: Buvanesvari Ramachandira Moorthy , Suresh Joseph Kanagaraj
Published: June 2020

Named data networking (NDN) corresponds to content‐centric networking, content‐based networking, and data‐oriented networking. Future internet architecture is modelled to overcome the fundamental limitations of the present internet protocol‐based internet and to provide specific strong security. Caching is a key NDN feature in the network. However, pervasive caching strengthens security issues in particular cache pollution assaults including cache poisoning (e.g. presenting malicious content in caches as false‐locality) and cache pollution (e.g. unpopular content is ruined with cache locality as locality‐disruption). In this work, a new cache replacement method based on the radial basis function neural network (RBFNN) is proposed to detect and mitigate the cache pollution attacks in NDN. RBFNN framework is constructed utilising the input associated with the cached content inherent characteristics and output data associated with the content type, i.e. locality‐disruption, false‐locality, and healthy. Experimental results show the efficiency as well as the effectiveness of the proposed method in terms of hit damage ratio and computational time.
Efficient certificate‐based aggregate signature scheme for vehicular ad hoc networks
Authors: Chen Jian‐Neng , Huang Zhen‐Jie , Zhou Yu‐Ping , Zou Fu‐Min , Chen Chien‐Ming , Wu Jimmy Ming‐Tai , Wu Tsu‐Yang
Published: June 2020

As vehicle speed is fast and on board units' (OBUs) computing power, storage space, bandwidth and other resources are very limited, the efficiency of message transmission in vehicular ad hoc network is of great concern. Certificate‐based aggregate signature scheme provides a way to combine numerous signatures into one short signature. The authors propose a certificate‐based aggregate signature scheme for vehicular ad hoc networks. In this study, the authors prove that the proposed scheme is secure against forgery attack in the random oracle model and under the computational Diffie–Hellman problem. It is efficient and suitable for vehicular ad hoc networks.
Compact CRB for delay, Doppler, and phase estimation – application to GNSS SPP and RTK performance characterisation
Authors: Medina Daniel , Ortega Lorenzo , Vilà‐Valls Jordi , Closas Pau , Vincent Francois , Chaumette Eric
Published: June 2020

The derivation of tight estimation lower bounds is a key tool to design and assess the performance of new estimators. In this contribution, first, the authors derive a new compact Cramér–Rao bound (CRB) for the conditional signal model, where the deterministic parameter's vector includes a real positive amplitude and the signal phase. Then, the resulting CRB is particularised to the delay, Doppler, phase, and amplitude estimation for band‐limited narrowband signals, which are found in a plethora of applications, making such CRB a key tool of broad interest. This new CRB expression is particularly easy to evaluate because it only depends on the signal samples, then being straightforward to evaluate independently of the particular baseband signal considered. They exploit this CRB to properly characterise the achievable performance of satellite‐based navigation systems and the so‐called real‐time kinematics (RTK) solution. To the best of the authors’ knowledge, this is the first time these techniques are theoretically characterised from the baseband delay/phase estimation processing to position computation, in terms of the CRB and maximum‐likelihood estimation.
The impact of the temperature of biodiesel from animal fats on nitrogen oxides emissions
Authors: Czechlowski Mirosław , Gracz Weronika , Marcinkowski Damian , Golimowski Wojciech , Kowalczyk-Juśko Alina
Published: June 2020

The current results of NOx emission tests of diesel engines fuelled with unconventional biofuels are not unambiguous. Therefore, the aim of the study was to analyze the influence of temperature of methyl esters from animal fats (AFME) on the level of NOx emission. The test was carried out on an experimental stand equipped with a diesel engine with a power of 9.5 kW. The engine was controlled by an electric generator from which the generated energy was fed into the electric network. The test was carried out in accordance with the D1 standard for power generators. As a result of the statistical analysis, significant differences were found for the values of average unit emissions of nitrogen oxides obtained for individual phases of D1 tests, i.e. engine loads amounting respectively to 50%, 75% and 100% of the nominal value of engine torque. On the basis of the test results, a significant influence of fuel temperature on NOx reduction can be found. Increase of fuel temperature by 50°C resulted in reduction of emissions by 6% on average.
The impact of the temperature of rapeseed oil methyl esters on nitrogen oxides emissions
Authors: Gracz Weronika , Czechlowski Mirosław , Marcinkowski Damian , Golimowski Wojciech , Pochwatka Patrycja
Published: June 2020

The purpose of the tests described in this publication was to examine the effect of the temperature of the biodiesel burned, resulting from the transesterification of rapeseed oil with methanol, on the level of nitrogen oxides emissions. The tests were carried out on a test stand equipped with a 9.5 kW engine. Electricity was transffered directly to the power grid. The measurements were started after the engine has warmed up, when the oil temperature exceeded 85°C. In the first stage, the engine was loaded with the maximum achievable torque (100%), in the second stage the torque was set at 75% of the maximum value, and for measurements in the third stage the torque was 50% of the maximum value. Three tests were carried out, one for each of the three fuel temperatures: 20, 40 and 55°C.
The state and the perspectives of the eco-energy infrastructure development in Biała Podlaska County (Poland). Part II Estimation of solid biomass resources for energy purposes
Authors: Kowalczyk-Juśko Alina , Listosz Agnieszka , Mazur Klaudia , Maciąg Michał , Pochwatka Patrycja , Mazur Andrzej
Published: June 2020

The paper estimates the possibility of obtaining solid biomass for energy purposes in the Biała Podlaska County (Lublin Voivodeship, Poland). The estimates were based on data on: forest area, orchards and tree stands, land use, crop structure, animal population, and marginal land area in the County. It was found that in most communes, there are great possibilities of obtaining biomass for energy purposes. The largest resource is straw (243,501 Mg per year), which should first be used in agriculture as animal litter and organic fertilizer. Only its surplus can be intended for the combustion and production of pellets and briquettes. In the County, large areas of poor quality land were inventoried, on which perennial energy plants with low requirements can be grown. Up to 113,595 Mg of biomass can be obtained there. The basic condition for the development of targeted energy crops is the emergence of a biomass market: installations that convert biomass into fuels or produce energy on a local scale and sell it to power plants. Currently, a commonly used resource is wood biomass from forests and wood processing, which is used as fuel in domestic boilers, as well as for the production of pellets and briquettes.
Eco Green Campus: Challenges and Opportunities. The Study Case of Polytechnic Institute of Beja
Authors: Pardal Ana , Romeira Telma , Durão Anabela
Published: June 2020

Higher Education Institutions have an important role in the promotion of sustainability. The sustainability has been seen not only as a component of education, research and innovation, but also as a social learning process within and beyond academia. The adherence of the four schools that belongs to IPBeja, to the Eco-Schools Program allows the environmental analysis of each. The present work intends to contribute to the creation of the Eco Green Campus in to Polytechnic Institute of Beja (IPBeja). Environmental audits were carried out on the four Schools and in the IPBeja common services facilities. The results shows that it is necessary to implement some measures in order to IPBeja become an Eco Green Campus, involving all academic community: improvement of resource management; reduction of waste and effluent production; waste recovery; reduction of water and energy consumption; use of renewable energy; promotion of sustainable mobility and adoption of sustainable public procurement. It was proposed a concept of an Eco Green Campus, the IPBeja Environmental Policy and Environmental Best Practices Guide, oriented for decision-makers and for the entire academic community. The creation of an Eco Green Campus is simultaneously a challenge and an opportunity to contribute and promote the Circular Economy.
Effects of ibuprofen and venlafaxine on behavioural parameters in freshwater bivalve Unio tumidus
Authors: Chmist-Sikorska Joanna , Szoszkiewicz Krzysztof , Wencka Arkadiusz , Szczepaniak Martyna , Szymczak Joanna , Kujawski Maciej
Published: June 2020

The pollution of aquatic ecosystems by pharmaceuticals is presently recognized as a serious threat. The drug residues may contaminate surface waters via sewage discharges as well as improper disposal of industrial waste. Very few studies focused on the effects of drug pollutants on behaviour of invertebrates. In this study the effects of ibuprofen and venlafaxine on activity of the Unio tumidus were studied. Changes in behaviours were analysed at concentrations corresponding to wastewater discharges (3.4, 6.8 and 13.6 μgL−1). At dosage of 3.4 μgL−1, ibuprofen affected the activity time and shell opening level. The reduction in activity was particularly evident during the first few days. The same dose of venlafaxine caused hyperactivity of bivalves during the first few days of exposition. The highest doses (13.6 μgL−1) same drugs promoted reduction of activity and shell opening level. Moreover, exposure to these drugs resulted in the reduced water filtering time and hence its purification. The Unio tumidus reaction may indicate negative reaction of other aquatic species to the tested drugs.
Landscape indicators as a tool of assessing landscape quality
Authors: Sowińska-Świerkosz Barbara , Michalik-Śnieżek Malwina
Published: June 2020

Landscape quality (LQ) is understood as the state in which its (landscape) spatial, functional and visual structure is found at a given time. To measure this landscape characteristic different research methods and data types are needed including GIS techniques and remote sensing data as well as interviews and questionnaires, results of social perception studies, analysis of documents, registers and statistical data, landscape visual studies and 3D drawings. Presented study aims to fully analyze the LQ of the Roztocze region based on above mentioned methods. To do so, the categorization of 24 quantitative indices was applied. Results indicated high structural and ecological values, medium visual values and values of spatial harmony and low cultural and perceptual properties of analyzed area. The study results also showed the great importance of spatial data and GIS techniques in LQ assessment.
Forecasting Wind Speed using Artificial Neural Networks – A Case Study of a Potential Location of Saudi Arabia
Authors: Faniband Yunus Parvej , Shaahid S. M.
Published: June 2020

The growing concerns regarding the depletion of oil/gas reserves and global warming have made it inevitable to seek energy from wind and other renewable energy resources. Forecasting wind speed is a challenging topic and has important applications in the design and operation of wind power systems, particularly grid connected renewable energy systems, and where forecasting wind speed helps in manipulating the load on the grid. Modern machine learning techniques including neural networks have been widely used for this purpose. As per literature, various models for estimating the hourly wind speed one hour ahead and the hourly wind speed data profile one day ahead have been developed. This paper proposes the use of Artificial Intelligence methods (AI) which are most suitable for the prediction and have provided best results in many situations. AI method involves nonlinear (or linear) and highly complex statistical relationships between input and output data, such as neural networks, fuzzy logic methods, Knearest Neighbors algorithm (KNN) and Support Vector Machine (SVM). AI methods are promising alternatives for predicting wind speed and understanding the wind behavior for a particular region. In the present study (as a case-study), hourly average wind speed data of 13 years (1970-1982) of Qaisumah, Saudi Arabia has been used to evaluate the performance of ANN model. This data has been used for training the neural network. ANN is trained multiple times with different number of hidden neurons to forecast accurate wind speed. The efficiency of proposed model is validated by predicting wind speed of the Qaisumah region with the measured data. Mean Square Error (MSE) and mean absolute percentage error (MAPE values) for proposed model are found to be 0.0912 and 6.65% respectively.
The Use of Thermoelectric Generators With Home Stoves
Authors: Żołądek Maciej , Papis Karolina , Kuś Jakub , Zając Michał , Figaj Rafał , Rudykh Kyrylo
Published: June 2020

One of waste heat recovery technologies are thermoelectric generators, which allow direct conversion heat to energy. In the face of shrinking fossil fuels resources, simultaneous increase of global energy demand and level of pollution it is becoming more and more important to introduce technologies enabling fullest utilization of fuels. In the paper, tests of water and air cooled thermoelectric generators mounted on the stove were described. Problems that occurred while operation of the system and its solutions were presented. Analysis of factors influencing incineration process, therefore affecting produced electrical energy was carried out. Power and voltage-current characteristics of generators were drawn up. A possible electrical energy yield in conditions described in this paper was also estimated.
Simplified Seismic Loss Estimation of RC Frame using Component-performance-based Methodology
Authors: Qiao Shengfang , Tang Mengxiong , Han Xiaolei , Chen Hang , Hu Han , Hu Hesong , Liu Cunlin , Hou Zhenkun
Published: June 2020

A framework of simplified probabilistic seismic loss estimation of RC frame using component- performance -based methodology was presented in this paper. Firstly, component- performance -based methodology was introduced, and component performance level was measured using elasto-plastic rotation angle of structural component. Then structural performance level was determined by the statistics of damaged components distribution. Additionally, the relationship between the structural performance level and loss ratio of RC frame was established. Last, expected seismic loss ratio of 3-storey RC frame was studied in detail. This study reveals that the simplified probabilistic framework proposed herein could be used in RC frame.
Modeling the spatial propagation of Aβ oligomers in Alzheimer’s Disease
Authors: Andrade-Restrepo Martin , Lemarre Paul , Pujo-Menjouet Laurent , Tine Leon Matar , Ciuperca Sorin Ionel
Published: June 2020

Recent advances in the study of Alzheimer’s Disease and the role of Aβ amyloid formation have caused the focus of biologists to progressively shift towards the smaller protein assemblies, the oligomers. These appear very early on in the disease progression and they seem to be the most infectious species for the neurons. We suggest a model of spatial propagation of Aβ oligomers in the vicinity of a few neurons, without considering the formation of large ﬁbrils or plaques. We also include a simple representation of the oligomers neurotoxic effect. A numerical study reveals that the oligomers spatial dynamics are very sensitive to the balance between their diffusion and their replication, and that the outcome in terms of the progression of AD strongly depends on it.
Horizontal gene transfer: numerical comparison between stochastic and deterministic approaches
Authors: Calvez Vincent , Figueroa Iglesias Susely , Hivert Hélène , Méléard Sylvie , Melnykova Anna , Nordmann Samuel
Published: June 2020

Horizontal gene Transfer (HT) denotes the transmission of genetic material between two living organisms, while the vertical transmission refers to a DNA transfer from parents to their offspring. Consistent experimental evidence report that this phenomenon plays an essential role in the evolution of certain bacterias. In particular, HT is believed to be the main instrument of developing the antibiotic resistance. In this work, we consider several models which describe this phenomenon: a stochastic jump process (individual-based) and the deterministic nonlinear integrodifferential equation obtained as a limit for large populations. We also consider a Hamilton-Jacobi equation, obtained as a limit of the deterministic model under the assumption of small mutations. The goal of this paper is to compare these models with the help of numerical simulations. More specifically, our goal is to understand to which extent the Hamilton-Jacobi model reproduces the qualitative behavior of the stochastic model and the phenomenon of evolutionary rescue in particular.
Modeling and analysis of adipocytes dynamic with a differentiation process
Authors: Gilleron Jérôme , Goudon Thierry , Lagoutière Frédéric , Martin Hugo , Mauroy Benjamin , Millet Pascal , Ribot Magali , Vaghi Cristina
Published: June 2020

We propose in this article a model describing the dynamic of a system of adipocytes, structured by their sizes. This model takes into account the differentiation of a population of mesenchymal cells into preadipocytes and of preadipocytes into adipocytes; the differentiation rates depend on the mean adipocyte radius. The considered equations are therefore ordinary differential equations, coupled with an advection equation, the growth rate of which depends on food availability and on the total surface of adipocytes. Since this velocity is discontinuous, we need to introduce a convenient notion of solutions coming from Filippov theory. We are consequently able to determine the stationary solutions of the system, to prove the existence and uniqueness of solutions and to describe the asymptotic behavior of solutions in some simple cases. Finally, the parameters of the model are ﬁtted thanks to some experimental data and numerical simulations are displayed; a spatial extension of the model is studied numerically.
Evidenzbasierte Armrehabilitation nach Schlaganfall – ein Überblick
Authors: Platz Thomas
Published: June 2020

Führt bei Patienten mit einer Armparese nach Schlaganfall die rehabilitative Therapie in unterschiedlicher „Dosierung“ oder bei unterschiedlichen Inhalten zu einer Reduktion der Parese, einer Verbesserung der aktiven Bewegungsfähigkeit und Kraft sowie der Armaktivitäten? Dieser Frage geht der folgende Artikel nach.
Myocardial Mapping in Systemic Sarcoidosis: A Comparison of Two Measurement Approaches
Authors: Dabir Darius , Luetkens Julian , Kuetting Daniel , Nadal Jennifer , Schild Hans Heinz , Thomas Daniel
Published: June 2020

Purpose To investigate if T1 and T2 mapping is able to differentiate between diseased and healthy myocardium in patients with systemic sarcoidosis, and to compare the standard mapping measurement (measurement within the whole myocardium of the midventricular short axis slice, SAX) to a more standardized method measuring relaxation times within the midventricular septum (ConSept).

Materials and Methods 24 patients with biopsy-proven extracardiac sarcoidosis and 17 healthy control subjects were prospectively enrolled in this study and underwent CMR imaging at 1.5 T including native T1 and T2 mapping. Patients were divided into patients with (LGE+) and without (LGE–) cardiac sarcoidosis. T1 and T2 relaxation times were compared between patients and controls. Furthermore, the SAX and the ConSept approach were compared regarding differentiation between healthy and diseased myocardium.

Results T1 and T2 relaxation times were significantly longer in all patients compared with controls using both the SAX and the ConSept approach (p < 0.05). However, LGE+ and LGE– patients showed no significant differences in T1 and T2 relaxation times regardless of the measurement approach used (ConSept/SAX) (p > 0.05). Direct comparison of ConSept and SAX T1 mapping showed high conformity in the discrimination between healthy and diseased myocardium (Kappa = 0.844).

Conclusion T1 and T2 mapping may not only enable noninvasive recognition of cardiac involvement in patients with systemic sarcoidosis but may also serve as a marker for early cardiac involvement of the disease allowing for timely treatment. ConSept T1 mapping represents an equivalent method for tissue characterization in this population compared to the SAX approach. Further studies including follow-up examinations are necessary to confirm these preliminary results.

Key Points: 

Citation Format
Avaliação do uso de aplicativo de celular para auxílio no processo de reabilitação da cirurgia do ombro
Authors: Giusti André Luis , Reginaldo Sandro da Silva , Caixeta Thiago Barbosa , Chaibe Eduardo Damaceno , Moraes Leonardo Vieira Santos , Oliveira Rodolpho Lemes de
Published: June 2020

Objetivo Avaliar a qualidade de um aplicativo de celular desenvolvido para orientar pacientes em período pós-operatório de procedimentos cirúrgicos do ombro.

Métodos Desenvolveu-se um aplicativo gratuito e de fácil acesso para auxiliar os pacientes em domicílio. Os indivíduos foram monitorados quanto ao uso do aplicativo e adaptação à sua prática antes do início da fisioterapia. Ao final de 6 semanas, aplicou-se um questionário qualitativo para avaliar a usabilidade do aplicativo.

Resultados Um total de 97% dos respondentes afirmaram que foi fácil executar o download do aplicativo, que os exercícios sugeridos foram prontamente entendidos, e relataram que indicariam o aplicativo. Noventa e três por cento da amostra concorda que o aplicativo fez com que se sentissem mais participativos com relação ao tratamento de sua doença, enquanto 90% consideraram o aplicativo autoexplicativo.

Conclusão O uso de uma plataforma virtual é uma ferramenta de compreensão sobre o tratamento e auxilia na prescrição médica de exercícios pós-operatórios domiciliares.
A presença do pé torto congênito atrasa o início da marcha?
Authors: Bertinatto Ronan , Forlin Edilson , Wustro Leonardo , Tolotti Jacqueline Ojeda , de Souza Geovanna Andrade Labres
Published: June 2020

Objetivo O pé torto congênito (PTC) é uma das alterações ortopédicas congênitas que mais frequentemente necessita tratamento intensivo, e pouco se sabe o impacto desse tratamento no desenvolvimento motor. O presente estudo buscou avaliar se pacientes portadores de PTC tratados pelo método de Ponseti desenvolvem a marcha mais tardiamente comparado a um grupo controle e analisar possíveis fatores relacionados.

Métodos Incluídos pacientes nascidos a termo, com < 6 meses de idade, sem tratamento prévio e com seguimento mínimo de 24 meses. O grupo controle foi de pacientes sem alterações musculoesqueléticas, atendidos no mesmo período da realização do presente estudo.

Resultados Um total de 97 pacientes formaram o grupo de estudo e 100 o grupo controle. A média de idade no início da marcha no grupo de estudo foi de 14,7 ± 3,2 meses, e 12,6 ± 1,5 meses (p < 0,05) no grupo controle. Fatores relacionados à marcha tardia foram: idade de início do tratamento > 3 semanas, número de trocas gessadas > 7, recidiva e não realização da tenotomia de Aquiles. Idade de início do tratamento > 3 semanas esteve relacionada a maior número de trocas de gessos. Gênero e lateralidade não tiveram relação com a marcha tardia.

Conclusão Pacientes com PTC tratados com o método de Ponseti apresentam marcha independente aproximadamente 2 meses mais tarde do que o grupo controle. Início mais tardio do tratamento, maior número de trocas de gessos, recidiva e não realização da tenotomia de Aquiles foram relacionados com atraso da marcha.
Transjugular Intrahepatic Portosystemic Shunts in High-Risk Patients
Authors: Shin David S. , Vo Hong , Johnson Guy , Pichler Raimund , Biggins Scott W.
Published: June 2020

Cirrhosis with complications of portal hypertension portends a poor prognosis. Transjugular intrahepatic portosystemic shunts (TIPS) can successfully treat some of these complications in select patients. While the safety and efficacy of TIPS have improved significantly over the past decade, certain patients are categorized as high-risk based on various demographic, laboratory, and comorbid factors. Herein, we provide an in-depth review of TIPS in these settings, including high model for end-stage liver disease score, hepatic malignancy, advanced age, cardiac disease, renal dysfunction, and pregnancy, and discuss their impact on patient selection and procedural considerations.
Scapholunate Diastasis in Distal Radius Fractures: Fracture Pattern Analysis on CT Scans
Authors: Özkan Sezai , Mudgal Chaitanya S. , Jupiter Jesse B. , Bloemers Frank W. , Chen Neal C.
Published: June 2020

Objectives Our understanding of distal radius fractures with concomitant scapholunate (SL) diastasis primarily comes from plain radiographs and arthroscopy. The clinical implications of SL diastasis are not clear. The aim of this study is to describe fracture characteristics of distal radius fractures on computed tomography (CT) scans in patients with distal radius fractures and static SL diastasis.

Methods We queried our institutional databases to identify patients who were treated for a distal radius fracture, had a CT scan with a wrist-protocol, and static SL diastasis on their CT scan. Our final cohort consisted of 26 patients. We then collected data on their demographics, injury, treatment, evaluated injury patterns, and measured radiographic SL characteristics. Our study cohort consisted of 11 men (42%) and almost half of our cohort (n = 12; 46%) had a high-energy mechanism of injury. The majority of the patients (n = 20; 77%) had operative treatment for their distal radius fracture and two patients (7.7%) had operative treatment of their SL injury.

Results The mean SL distance was 3.5 ± 1.1 mm. Twenty patients (77%) had an intra-articular fracture. In these patients, we observed three patterns: (1) scaphoid facet impaction; (2) lunate facet impaction; and (3) no relative impaction. We observed other injury elements including rotation of the radial styloid relative to the lunate facet and partial carpal subluxations.

Conclusion Static SL dissociation in the setting of distal radius fractures may be an indication of a complex injury of the distal radius, which may not be directly apparent on plain radiography. If these radiographs do not demonstrate impaction of the lunate or scaphoid facet, a CT scan may be warranted to have a more detailed view of the articular surface.

Level of Evidence This is a Level III, diagnostic study.
Arthroscopic Bone Grafting and Arthrodesis of Partial Lunotriquetral Coalition
Authors: Sivakumar Brahman S. , Smith Nicholas C.
Published: June 2020

Background Lunotriquetal coalition is the most common carpal coalition that can be symptomatic if trauma disrupts the syndesmosis or synchondrosis or if degenerative changes develop between the abnormal articulating surfaces.

Case Description A 15-year-old boy presented with a symptomatic lunotriquetral coalition after a fall 2 years prior. Following appropriate investigation, he was managed via arthroscopic debridement, bone grafting, and lunotriquetral arthrodesis.

Literature Review The majority of symptomatic lunotriquetral coalitions have been managed with open arthrodesis. There is only one prior report of arthroscopic arthrodesis of this articulation that did not utilize bone graft.

Relevance This report details the procedure to allow arthroscopic lunotriquetral arthrodesis with bone grafting, conveying osteogenic properties, and encouraging incorporation at the fusion site while maintaining the dorsal ligaments.
Observing mode-dependent wavelength-to-time mapping in few-mode fibers using a single-photon detector array
Authors: Chandrasekharan Harikumar K. , Ehrlich Katjana , Tanner Michael G. , Haynes Dionne M. , Mukherjee Sebabrata , Birks Tim A. , Thomson Robert R.
Published: June 2020

Wavelength-to-time mapping (WTM)—stretching ultrashort optical pulses in a dispersive medium such that the instantaneous frequency becomes time-dependent—is usually performed using a single-mode fiber. In a number of applications, such as time-stretch imaging (TSI), the use of this single-mode fiber during WTM limits the achievable sampling rate and the imaging quality. Multimode fiber based WTM is a potential route to overcome this challenge and project a more diverse range of light patterns. Here, we demonstrate the use of a two-dimensional single-photon avalanche diode (SPAD) array to image, in a time-correlated single-photon counting (TCSPC) manner, the time- and wavelength-dependent arrival of different spatial modes in a few-mode fiber. We then use a TCSPC spectrometer with a one-dimensional SPAD array to record and calibrate the wavelength-dependent and mode-dependent WTM processes. The direct measurement of the WTM of the spatial modes opens a convenient route to estimate group velocity dispersion, differential mode delay, and the effective refractive index of different spatial modes. This is applicable to TSI and ultrafast optical imaging, as well as broader areas such as telecommunications.
Ensemble model output statistics as a probabilistic site-adaptation tool for solar irradiance: A revisit
Authors: Yang Dazhi
Published: June 2020

Previously, in the study by Yang [J. Renewable Sustainable Energy 12, 016102 (2020)], probabilistic site adaptation was demonstrated for the first time. This technique leverages the ensemble model output statistics (EMOS), post-processes the empirical distribution formed by m gridded solar irradiance estimates from different satellite-derived and reanalysis databases, and thus obtains a final predictive distribution of the site-adapted irradiance, which has a normal density. That said, three questions were later thought of: (1) can post-processing the clear-sky index, instead of irradiance, lead to better site-adaptation performance; (2) will the parameter estimation strategy substantially affect model performance; and (3) how does the normality assumption hold in reality? In this paper, I revisit the probabilistic site-adaptation problem and aim to address these questions. In summary, it is found that (1) building EMOS models on irradiance and on the clear-sky index leads to similar model performance; (2) the choice of minimizing the continuous ranked probability score and the ignorance score needs to be tailored to the problem at hand; and (3) using a truncated normal predictive distribution in EMOS does not seem to possess an advantage over using a normal predictive distribution.
The promise of single-cell mechanophenotyping for clinical applications
Authors: Kozminsky Molly , Sohn Lydia L.
Published: June 2020

Cancer is the second leading cause of death worldwide. Despite the immense research focused in this area, one is still not able to predict disease trajectory. To overcome shortcomings in cancer disease study and monitoring, we describe an exciting research direction: cellular mechanophenotyping. Cancer cells must overcome many challenges involving external forces from neighboring cells, the extracellular matrix, and the vasculature to survive and thrive. Identifying and understanding their mechanical behavior in response to these forces would advance our understanding of cancer. Moreover, used alongside traditional methods of immunostaining and genetic analysis, mechanophenotyping could provide a comprehensive view of a heterogeneous tumor. In this perspective, we focus on new technologies that enable single-cell mechanophenotyping. Single-cell analysis is vitally important, as mechanical stimuli from the environment may obscure the inherent mechanical properties of a cell that can change over time. Moreover, bulk studies mask the heterogeneity in mechanical properties of single cells, especially those rare subpopulations that aggressively lead to cancer progression or therapeutic resistance. The technologies on which we focus include atomic force microscopy, suspended microchannel resonators, hydrodynamic and optical stretching, and mechano-node pore sensing. These technologies are poised to contribute to our understanding of disease progression as well as present clinical opportunities.
Developing and validating protocols for mechanical isolation of guard-cell enriched epidermal peels for omics studies
Authors: Rasouli Fatemeh , Kiani-Pouya Ali , Zhang Heng , Shabala Sergey
Published: June 2020

Stomata, which are microscopic valves on the leaf surface formed by two guard cells (GC), play a critical role in the regulation of leaf water and gas exchange and, hence, determine plant adaptive potential. However, little data is available on GC biochemistry, protein abundance and gene expression, mainly due to technical difficulties and challenges in isolating sufficient amounts of high-quality pure GC. In the present study we applied some modifications to the mechanical isolation of guard-cell to generalise this method for diverse growth conditions as well as plant species. Epidermal peel fragments enriched in guard cells were mechanically isolated from quinoa, spinach and sugar beet leaves grown at two conditions (normal and salt stress). Multiple analysis was performed to confirm the suitability and superiority of the modified technique to the original method. At the first step, the viability and purity of GC-enriched epidermal fragments were assessed under the microscope. Then, the RNA integrity, gene expression, and 1D SDS-PAGE tests were performed to validate the suitability of this technique for omics studies. The data revealed a wide range of proteins as well as a high integrity of RNA extracted from guard cell samples. The expression level of several GC-specific genes and mesophyll-dominant genes were investigated using a comparative analysis of transcriptome datasets of GC and whole-leaf samples. We found that Rubisco and photosynthesis-related proteins such as chlorophyll a/b binding protein were substantially higher in the whole leaf compared with the GCs. More importantly, GC-specific genes such as OST1, SLAC1, MYB60, FAMA and HT1 were highly expressed in the GCs, confirming that our guard cell preparation was highly enriched in GC gene transcripts. Real-time quantitative reverse transcription PCR further confirmed the efficacy of the GC isolation technique for exploring responses of GC to diverse types of stress at the molecular level.