bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of anodic ZrO2 nanostructures in NH4F/ethylene glycol electrolyte
Authors: Rozana M , Lockman Z
Published: June 2020

The aim of this study is to investigate the morphology and surface species of ZrO2 film formed in a fluorinated ethylene glycol electrolyte by anodization process. In this work, no water was added into the NH4F/ethylene glycol electrolyte. Possible formation mechanism of anodic ZrO2 nanostructures in the NH4F/EG electrolyte was also explored. As a result, the porous ZrO2 film with the thickness of 1.5 – 2.5 µm was produced. From the top view, it is observed that the surface consists of rings with diameters of 100 – 160 nm. However, the oxide does not consist of any tubular structure. The FTIR spectrum of the film shows that the top of anodic ZrO2 film is covered by anion contamination, e.g. OH− and CO3
−.
Effect of pH on Swelling Profile of Glutaraldehyde Crosslinked Adenanthera pavonina L. Galactomannan
Authors: Cavalcante L A , Batista B S , Fonseca A P G , Balteiro A J D , Amaral F M B , Mendes F , Macêdo A A M
Published: June 2020

Galactomannans are neutral natural polymers isolated from legume endosperm and with wide use in the biomedical field. As a consequence, there is a need to investigate materials for their properties in order to better understand and apply them. In this study, we analyzed the influence of pH medium on the crosslinking process of galactomannan and glutaraldehyde, changing the pH medium from 3 to 7, using a strong base. The Fourier Transform Infrared Spectrum (FTIR) and the swelling profiles of the glutaraldehyde crosslinked galactomannan were evaluated. We have found that the glutaraldehyde-galactomannan crosslinking process is highly sensitive to the variation of pH medium. According to our results, best swelling capacity was achieved for samples prepared at pH=5, suggesting that this pH medium conditions is suitable for possible production of hydrogels prepared from glutaraldehyde-galactomannan.
Three-dimensional numerical simulation of solidification microporosity and microstructure of aluminum alloys
Authors: Gu C , Luo A A
Published: June 2020

A three-dimensional model was developed to study microporosity evolution with grain growth during solidification by cellular automaton method. The simulations are able to show the evolution and morphology of both grain structure and porosity. The effects of shrinkage pressure and initial hydrogen content on porosity evolution and final porosity percentage are modeled and related to the location-specific microstructure of the solidified products. A wedge die casting, providing samples of different cooling rates, was used to validate the simulation results. X-ray micro-tomography was performed to obtain the relevant porosity information. The simulated porosity size, percentage and distribution considering both shrinkage pressure and hydrogen content were found to agree well with those from experimental measurements.
In situ observation of directional solidification in Ga-In alloy under a transverse DC magnetic field
Authors: He S , Shevchenko N , Eckert S
Published: June 2020

The directional solidification of a Ga-25wt%In alloy under the effect of a transverse DC magnetic field is investigated by X-ray radiography. The magnetic field pointing parallel to the X-ray beam is generated by two ring-shaped permanent magnets. The magnetic field reaches values up to ∼0.19 T in the field of view. The dendritic growth and the flow patterns of Ga-rich plumes migrating along the solidification front are captured and analysed. It shows that the local fluctuations of solute concentration are partially damped by the magnetic field. At the temperature gradient of 1 K/mm, the growth velocities of solidification front and plumes are not affected. In the case of higher temperature gradient (∼2 K/mm), the magnetic field causes an increase of the plume velocity in the horizontal direction and a decrease in the vertical direction while the velocity of the solidification front remains constant. Additionally, it is found that the magnetic field damps the fluctuations of tip velocity and refines the primary arm spacing. Above phenomena are discussed based on the thermoelectric magnetic and electromagnetic braking effects. The in situ experimental data are important for verification and improvement of the existing numerical simulations of solidification under the magnetic field.
Optimisation of the filling process in counter-gravity casting
Authors: Papanikolaou M , Saxena P , Pagone E , Salonitis K , Jolly M
Published: June 2020

Metal casting is one of the most energy-intensive manufacturing processes with limited resource efficiency. To solve the problem of high energy consumption, a novel counter-gravity casting process has been earlier introduced. This process also referred to as CRIMSON (Constrained Rapid Induction Melting Single Shot Up-Casting) makes use of melting metal, just enough to fill one mould cavity at a time. The molten metal is subsequently pushed into the mould with the help of a piston, using a counter-gravity controlled method. Although CRIMSON has been proven to be a highly efficient process with the potential to produce high quality final cast products, there is still room for optimisation of the process. The objective of this investigation is to estimate the optimum ingate velocity in order to ensure smooth filling of the mould and eventually reduce turbulence and the likelihood of defects in the final cast product. For this purpose, a computational framework integrating a CFD solver and an optimisation algorithm has been developed. The obtained results suggest that the optimised ingate velocity can contribute towards the smooth filling of the mould and effectively contribute towards the reduction of entrained air and surface defect concentration in the final cast product.
In situ analysis of cast irons mechanical behaviour using synchrotron x-ray tomography and 3DXRD
Authors: Sjögren T , Hall S , Elmquist L , Dartfeldt E , Larsson E , Majkut M , Elfsberg J , Skoglund P , Engqvist J
Published: June 2020

When subjecting cast irons to mechanical loading the deformation and damage mechanisms occur on a microstructural level and are dependent on the inherent microstructure. A deeper understanding of the relation between the different microstructural constituents and the macroscopic mechanical behaviour would be beneficial in material development efforts and for the ability to design and cast components with tailored properties. Traditionally, microscopy examinations on sectioned cast iron samples have been used when analysing the microstructure in cast irons. Since all microstructural heterogeneity is in three-dimensions (3D), methods that provide a three-dimensional characterisation are essential for a deeper understanding of, both the microstructural features as well as the deformation and damage of cast irons. Therefore, different cast iron grades have been studied using synchrotron X-ray tomography and 3D x-ray diffraction (3DXRD) at ESRF in Grenoble, France. The samples were stepwise loaded and unloaded in-situ at in the tomography/3DXRD set-up to study the deformation with regard to microstructural constituents and the microstructural evolution in 3D. Based on the 3D tomography image sequences, digital volume correlation (DVC) was used for full strain field analysis and for the analysis of damage and deformation mechanisms. In addition, 3DXRD data were analysed to provide details on the lattice parameters and lattice strain of individual ferrite grains. This work shows the possibilities of such synchrotron experiments for advanced study of the mechanical behaviour of cast iron.
Modelling macrosegregation modification in dc casting of aluminium alloys in sheet ingots accounting for inlet melt flow, equiaxed grain morphology and transport
Authors: Pakanati A , M’Hamdi M , Combeau H , Založnik M
Published: June 2020

Macrosegregation is a severe defect present in direct-chill (DC) cast aluminium ingots and billets. In the recent years, experimental studies were conducted to modify and to an extent optimize macrosegregation formation by modifying the inlet melt flow. Due to several limitations, the grain settling behavior and corresponding liquid flow pattern is difficult to analyze using experiments. Simulations on the other hand can provide this insight. However, conducting 2D sheet ingot simulations, as has been previously done, provides an incomplete description of flow pattern. To avoid this and as a first qualitative study, full scale 3D sheet ingot simulation results with two different inlets are presented in this paper. A simplified three-phase multiscale solidification model accounting for solidification shrinkage, natural convection and equiaxed grain growth and transport is used to conduct this study. We show that modification of inlet flow results in modification of grain settling and eventually leading to modification of macrosegregation. The impact of grain morphology is also additionally analyzed.
Modelling the evolution of MnS inclusions and macrosegregation during solidification using a three-phase model
Authors: Cai D , Li J , Dong H , Li J
Published: June 2020

Manganese sulphide (MnS) is one of the major non-metallic inclusion in steel which greatly impacts the properties of steels. Previous models have been developed to simulate the dynamics of MnS during solidification without considering the effects of macrosegregation formation. A comprehensive model incorporating the formation kinetics of MnS with a ternary macrosegregation model is presented to investigate the evolution of MnS inclusions and its effects on C and Mn macrosegregation. Classical nucleation theory and a diffusion-controlled growth model are applied to describe the evolution of MnS, which is fully coupled with a two-phase ternary alloy solidification model. The model considers the growth of columnar dendrite trunks, thermosolutal convection of the melt, solute transport by convection and inclusion floatation. It has been applied to a benchmark case, and reasonable results are obtained with a good agreement with the reported experimental ones. The effects of MnS behaviours on the segregation of different solute elements are discussed.
Effect of Al-V-B grain refiner on refining aluminium alloys: estimation from ab initio calculations
Authors: Ma S , Zong N , Dong H , Jing T
Published: June 2020

Ab initio calculations based on density functional theory were conducted to estimate the effect of Al-V-B grain refiner on refining aluminium alloys. Al-Ti-B, an industrial grain refiner, was investigated simultaneously to act as a reference. Six interfaces formed by (111) Al with (112) Al3V(Ti), V(Ti)-terminated (0001) V(Ti)B2 and B-terminated (0001) V(Ti)B2 were studied in detail. Interfacial lattice mismatch, work of adhesion and stain-free interfacial energy were calculated for each of these interfaces, respectively. Analysis of interfacial energy demonstrated that Al3V overlayers are less likely to form on the surface of (0001) VB2 surface compared with the Ti-related system. By combination of interfacial lattice mismatch and work of adhesion, it was concluded that VB2 is much more potent in refining aluminium alloys than TiB2, while Al3V is much weaker in nucleant potency compared with Al3Ti.
Observation of semisolid deformation by using 4D-CT and 3DXRD
Authors: Narumi T , Nakata T , Yasuda H
Published: June 2020

Time-resolved X-ray tomography (4D-CT) and three-dimensional X-ray diffraction (3DXRD) were performed to investigate semisolid deformation in Al–10mass%Cu alloy. The configurations of solid grains were observed in-situ by 4D-CT and the crystallographic orientations of grains were also measured by 3DXRD. Translation and rotation of the solid grains in the semisolid are quantitatively analysed by the reconstructed 3D images and the diffraction spots. Based on the in-situ observation, we discuss about the motion of the solid grains and the formation of the shear band during the semisolid deformation.
Predicting solidification cracking susceptibility of stainless steels using machine learning
Authors: Feng S , Dong H B
Published: June 2020

Machine learning, which reveals the complex nonlinear relationship in the archived data, is a powerful complement to theory, experiment, and modeling. In this study we attempted to predict solidification cracking susceptibility of stainless steels as a function of chemistry and processing parameters using machine learning with a data set that contains about 600 longitudinal varestraint test results. Four machine learning models, i.e. decision tree, random forest, shallow neural network and deep neural network, were used to mine the data set. Our results show: deep neural network outperformed other models in prediction accuracy; tree-based models have accepted accuracy and better interpretability than neural network; machine learning models transforms scattered experimental data points into a map in high-dimensional chemistry and processing parameters space. The combination of different machine learning models reveals that the solidification cracking susceptibility of stainless steels was mainly determined by the ratio of Ni content to Cr content, impurity element content and the strain level.
Probabilistic finite element analysis of the deflection on a beam
Authors: Meyghani B , Awang M , Wu C S
Published: June 2020

The reliability of complex systems can be quantified using probabilistic finite element analysis. A widely accepted approach is interlacing of probabilistic methods with commercial finite element solvers for evaluating the fatigue life. In this paper, the deflection of a beam is calculated using finite element method (ABAQUS® commercial software), then the results of the simulated model are employed in MATLAB®, which is used to determine the probability, reliability and the reliability index. It was found that the reliability index is around 1.2428, while the reliability value is calculated to be around 0.8930. From the calculations the values of the probability of failure (POF) was found to be around 0.1070. Finally, the results of the calculated maximum deflection have been compared and a good agreement is found.
Urethane based nanocomposite coated proppants for improved crush resistance during hydraulic fracturing
Authors: Qian T , Muhsan A S , Htwe L , Mohamed N , Hussein O
Published: June 2020

Hydraulic fracturing is one of the stimulation techniques that has been used to increase the hydrocarbon flow in unconventional reservoirs. Proppants are normally used to maintain the fracture conductivity and increase the permeability to oil. Due to high closure stress of the fractured formation, the conventional or uncoated proppants are easily crushed. Therefore, this project aims to increase the compressive strength of proppants by coating it with urethane based nanocomposite. Glass beads and fracking sands are coated with urethane resin and mixed with reduced graphene oxide (rGO) and carbon nanotubes (CNTs) respectively. Analysis testing using optical microscopy (OM) was conducted to study the morphology and microstructures of the coated proppants before and after crush test. Results showed remarkable improvement in proppants compression strength up to 41% and 35% after adding only 0.5% of CNTs and 0.1% of rGO respectively to the urethane resin coating. Therefore, it is recommended to utilize this material for coating the proppant with the optimized concentration to prevent pore plugging and proppant from flowing back, achieving the objective and solving both problem statements.
Performance and emission of turbocharger engine using gasoline and ethanol blends
Authors: Rosdi S M , Mamat R , Alias A , Hamzah H , Sudhakar K , Hagos F Y
Published: June 2020

In this decade, alternative fuels such as ethanol were extensively studied as an additive or substitute for increasing engine performance and decreasing the release of harmful gases into the environment. The objective of the study is to assess engine performance and exhaust emission using Gasoline and Ethanol blends in a turbocharged spark-ignition engine. Gasoline was used as a reference fuel, and ethanol was blended into gasoline at 10%, 20% and 30% named as E10, E20, and E30, respectively. The turbocharger spark ignition (SI) engine has been coupled to eddy current 100 kW dynamometer to measure the engine efficiency. The engine test was carried out at an engine speed of 3000 rpm and 40% wide open throttle (WOT). As results, the performance parameters such as volumetric efficiency (VE), rate of heat release (ROHR), brake mean effective pressure (BMEP), brake specific fuel consumption (BSFC) of the engine increased with gasoline-ethanol blends compared to gasoline. Also, the complete combustion contributed to the reduction of the hydrocarbon (HC), carbon dioxide (CO2) and nitrogen oxide (NOx) emissions. From the study, it can be concluded that ethanol is highly suited for turbocharged SI engines to reduce emissions and increase performance.
A simple and low-cost purification method for microbial-free water using zinc oxide nanoparticles
Authors: Muzaffar S , Naeem Aslam M , Rehman S , Umer S , Ahmed S , Zahra S R , Ahmad W , Anwar H
Published: June 2020

Availability of standard quality drinking water is very essential for all living-beings. Availability of drinkable water has become a biggest challenge for the whole world. Water is a vital necessity for living-beings. Contamination of water has caused the millions of deaths in every year. Therefore, it is dire need to develop and explore low cost and simple methods to obtain quality drinking water. Zinc oxide (ZnO) is good reactive agent that had used to immobilize the toxic substance and destroyed the virus from contaminated water. Zinc oxide nanoparticles (ZnO-NPs) were prepared by using zinc sulfate heptahydrate (ZnSO4. 7H2O) and sodium hydroxide (NaOH). As prepared zinc oxide nanoparticles (ZnO-NPs) were characterized by using different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis spectroscopy. From XRD results, average crystallite size of prepared ZnO-NPs was calculated using Scherrer’s equation and found to be 29 nm. SEM analysis showed that as prepared NPs has mixed morphology having hexagon and rod-like shapes. UV-Vis analysis showed that maximum absorbance range between 250 nm to 350 nm. After the characterization, zinc oxide nanoparticles (ZnO-NPs) were employed for purification of water. The treated water was then investigated by finding electrical conductivity (EC), analysis of pH, total dissolved solids (TDS), atomic absorption spectroscopy (AAS) for the study of heavy metals and colony forming units (CFU) for microbial count such as bacteria, virus and protozoa etc. It was found that water treated with ZnO killed 100 % of microorganism as compared to water without treatment of ZnO (63%).
Low voltage reliability equivalent using monte-carlo simulation technique
Authors: Fauzi N F M , Roslan N N R , Ridzuan M I M
Published: June 2020

Reliability is the ability of a system to supply continuous electricity to customer which ends with zero fault that occurs under a specific period of time. Most of the literature focus more on medium voltage (MV) and high voltage (HV) compared to the low voltage (LV) due to the general absence of exact data in LV network and sizing of LV network. In addition, an increament in size of the LV network makes the network more complex and difficult to assess. Therefore, in this paper, the performance of reliability in LV network will be evaluated in detailed network model. To reduce simulation time, methodology of reducing detailed network into an equivalent network is introduced. This equivalent network is obtained by simplifying the complex network using Monte-Carlo Simulation technique. The results in this research are quantified and compared between these detailed and equivalent networks in reliability indices; SAIFI, SAIDI and CAIDI. The values of SAIFI, SAIDI and CAIDI in detailed network are slightly higher than in equivalent network.
Experimental study on the effect of bed aspect ratio to the drying rate of chilli for swirling fluidized bed dryer
Authors: Basrawi M F , Redzlan F , Ibrahim T K , Yudin A S M
Published: June 2020

Swirling Fluidized Bed Dryer (FBD) has better performance because of the improvement of air flow with less pressure drop. However less study focus on the performance of swirling FBD especially at small-scale. Thus, the objective of this study is to investigate drying characteristics of green chillies at different ratio of chilli, Rchilli
and bed aspect ratio, RBed
by the swirling fluidized bed dryer. An electrical blower with 600 W of power was used as a main source to supply air at flow rate of 0.324 kg/s which equals to the velocity at the distributor of 8.25 m/s. The chamber has 400 mm height and 150 mm diameter with maximum capacity of 2 kg. The air distributor used has 67% inclination angle to provide air swirling inside the FBD. It was found that RBed
increased from 0.8 to 1.6, the drying performance decreased in which the final moisture ratio was higher at 0.72-0.79 for RBed
= 1.6 as compared to better moisture ratio at 0.18-0.24 for RBed
= 0.8. The drying rate was at 0.225-0.275 %/min for RBed
= 0.8, and 0.075-0.10 %/min for RBed
= 1.6. When the Rchilli
increased from 1:1 to 2:1, the drying performance showed slightly decreased. Moisture ratio also slightly increased from 0.18 to 0.24 for RBed
= 0.8, whereas from 0.72 to 0.79 for RBed
= 1.6. This finding suggest that the RBed
has more significant effect than Rchilli
.
Experimental study of drying characteristics of cocoa bean in a swirling fluidized bed dryer
Authors: Zulkarnain M A , Shahriman M K , Yudin A S M
Published: June 2020

Drying is a process to reduce the weight for easy transportation and enhance the shelf life of product without quality losses over an extended period of time. Cocoa bean is an agricultural product that contains high moisture. The drying process of cocoa bean was conducted by two methods which are conventional method and swirling fluidized bed dryer. The conventional method is by drying under the sunlight. By using swirling fluidized bed dryer, it can shorten the time where heater is used to supply heat in this experiment. This fluidized bed dryer functions by the addition of design of air distributor used in the experiment. The distributor installed to improve mixing inside the bed. Therefore, in order to minimize the cost of using high capacity blower as well as to reduce energy, viable design of air distributor which can contribute to low pressure drop and improved particulate mixing in fluidized bed is essential. A fluidized bed column of 108 mm in diameter with one slotted distributor with inclination angles of 45º is used in the experiment. We find the results by using 1kg sample for conventional method are 11 days drying time, 58.55% weight loss reduction, and 0.4145 moisture ratio. Meanwhile for swirling fluidized bed dryer the time required was 2 days, 59.16% weight loss reduction, and 0.4083 moisture ratio. Based on the results obtained, the drying by using swirling fluidized bed dryer is more efficient compare to conventional method.
The stability of TiO2/POE nanolubricant for automotive air-conditioning system of hybrid electric vehicles
Authors: Hamisa A H , Yusof T M , Azmi W H , Mamat R , Sharif M Z
Published: June 2020

Nanolubricant are containing nanoparticles that are mixed with the base lubricant. Nanoparticle consists of ultra-fine size of particles from 1 to 100 nm. It was widely used as additional material to enhance properties of lubricant. The thermo-physical properties of the nanolubricant enhanced and thus able to improve the performance of vapour compression refrigeration system (VCRS) and automotive air-conditioning (AAC) system. The stability condition is one of the priority in formulation of nanolubricant for new application in AAC system of hybrid electric vehicles (HEV). The main objective of this study is to investigate the stability of TiO2 nanoparticles dispersed in Polyol-Ester (POE) lubricant. The TiO2/POE nanolubricant was prepared at volume concentration of 0.01 to 0.1% using the two-step method without any surfactant. The stability investigations were conducted by using visual sedimentation observation, micrograph observation, UV-Vis Spectrophotometer measurement and zeta potential measurement. The findings by visual sedimentation observation showed the best stability condition for more than 14 days at 0.01% and 0.03% volume concentration. Meanwhile the optimum sonication time is observed at 5 hours by visual and supported by UV-Vis evaluation. Further, the concentration ratio from UV-Vis evaluation was recorded above 95% for 5 hours sonication time and more than 30 days observation. Finally, the Zeta potential for the present nanolubricant was measured with 81.1 mV and obtained within the range of very good stability condition. Hence, this can confirm a good stability condition for the present TiO2/POE nanolubricant. Further investigation is required for the properties evaluation and performance of the nanolubricant in AAC system of HEV.
TiO2-SiO2 nanofluid characterization: Towards efficient with water/ethylene glycol mixture for solar application
Authors: Fikri M A , Asri F F , Faizal W M , Adli H K , Mamat R , Azmi W H , Najafi G , Yusaf T
Published: June 2020

Nowadays renewable energy has been used widely as strong contenders to improve the plight of two billion people, mostly in rural areas, without access to modern forms of energy. In this study, the effect of using water/ethylene glycol-based TiO2-SiO2 nanofluid on the characteristic of the solar radiation test rig has been experimentally used to investigate the characteristic of TiO2-SiO2 nanofluid suspended in water/ethylene glycol for solar applications. The TiO2-SiO2 nanofluids were prepared at a volume concentration of 0.3, 0.5 and 0.7% and dispersed in a base fluid of water/ethylene glycol 60:40 and 70:30 TiO2-SiO2 with the one-step method. KD2 Pro measures thermal conductivity set equipment and viscosity by LVDV III Ultra Rheometer. Thermal conductivity results show that the increase with different temperatures but the temperature of viscosity decreases. For solar radiation test rig that the highest point indicates the end of the charging process and the beginning of the discharging process, the maximum concentrations of 0.7% are observed to consistently provide higher temperature output as compared to the other three concentrations of nanofluids based on solar radiation 300, 500 and 700 W/m2. Therefore, it can be concluded that the higher concentrations give ample time to the test tube to transfer the heat and thus increased its temperature during the charging process.
Organic-inorganic hybrid solar cells based on 1D ZnO/P3HT active layers and 0D Au as cathode
Authors: González Verónica , López Israel , Martín Palma Raul , Peña Yolanda , Gómez Idalia
Published: June 2020

In this paper two different methodologies for the assembling of organic-inorganic hybrid solar cells in 1D are presented: conventional and inverted. The conventional solar cell has the configuration of ITO/P3HT/ZnO/Au, while the inverted of ITO/ZnO/P3HT/Au. The active layers are composed of ZnO nanorods and P3HT nanorods. P3HT was synthesized by chemical oxidative polymerization and the nanorods were obtained by template assisted method. ZnO nanorods were synthesized by electrochemical method on ITO glass. The influence of the arrangement of the semiconductors was studied. The cathode of both solar cells was formed of gold nanoparticles (0D), synthesized by microwave method. The active layers were analyzed by UV–vis spectrophotometry, FTIR and SEM. Results of J-V curves indicate that the conventional solar cell has the highest current density due to the higher contact between the layers.
Stability and electronic properties of LaNiO2/SrTiO3 heterostructures
Authors: Bernardini F , Cano A
Published: June 2020

Infinite-layer nickelate thin films materialize an intriguing new platform for high-temperature unconventional superconductivity, with LaNiO2/SrTiO3 as reference setup. We discuss the relative stability of the elementary interfaces of this system and determine the corresponding electronic band structure. We find substantial changes compared to the bulk, in particular in relation to the 5d orbital contributions to the low-energy physics which can be totally replaced by purely Ni-3d flat bands. The d
9 configuration characteristic of cuprates can thus be supplemented by an extra interfacial ingredient destabilizing the normal non-superconducting state in these heterostructures.
Towards low- loss on-chip nanophotonics with coupled graphene and silicon carbide: a review
Authors: Rufangura Patrick , Folland Thomas G , Agrawal Arti , Caldwell Joshua D , Iacopi Francesca
Published: June 2020

The ability to control the interaction of light and matter at the nanoscale is at the heart of the field of nanophotonics. This subdiffractional confinement of light can be achieved through the stimulation of surface polaritons, most notably surface plasmon polaritons (SPPs). However, the high optical losses and lack of tunability of conventional plasmonic materials have hindered major progress in this field. In the search for alternative low-loss and tunable materials, graphene and polar dielectric materials are viewed as potential alternatives to more common metal-based plasmonic materials. In particular, the possibility of combining the tunable nature of graphene SPPs with the high-quality factors and long lifetimes of surface phonon-polaritons (SPhPs) modes supported in polar dielectric materials (e.g. SiC) offers great promise for advanced nanophotonic applications. The combination of graphene SPPs and SPhPs supported in SiC is even more pertinent as this material system can be realized in the form of epitaxial graphene (EG), whereby sublimation of silicon from a SiC results in a surface reconstruction into a graphene surface termination. This offers an ideal technology platform for realizing hybrid SPP-SPhP modes. In this review, we outline advances in graphene plasmonics and the generation of SPhPs in polar materials, in the context of epitaxial graphene. We review recent attempts at realizing such coupling of graphene SPPs with phonon and SPhP modes in SiC, as well as covering such modes in other polar materials and conclude with an overview of advantages and challenges for further advancement of nanophotonics based on graphene on silicon carbide for on-chip light manipulation.
Peripheral Blood Examination Findings in SARS-CoV-2 Infection
Authors: Nazarullah Alia , Liang Christine , Villarreal Andrew , Higgins Russell A , Mais Daniel D
Published: June 2020

Objectives

Peripheral blood abnormalities in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been fully elucidated. We report qualitative and quantitative peripheral blood findings in coronavirus disease 2019 (COVID-19) patients and compare them with a control group.

Methods

We reviewed electronic medical records, complete blood counts, peripheral blood smears, and flow cytometry data in 12 patients with SARS-CoV-2. These were compared with 10 control patients with symptoms suspicious for SARS-CoV-2 but who tested negative.

Results

No significant differences were noted in blood counts, except that absolute lymphopenia was present frequently in the control group (P < .05). Acquired Pelger-Huët anomaly (APHA) was noted in all COVID-19 cases, in most cases affecting over 5% of granulocytes. This contrasted with APHA in only 50% of control cases, affecting fewer than 5% of granulocytes in all cases (P < .05). Monolobate neutrophils were exclusive to COVID-19 cases. COVID-19 patients had greater frequency of plasmacytoid lymphocytes (P < .05). Flow cytometry data revealed absolute CD3+ T-cell count reduction in 6 of 7 patients; all of them required mechanical ventilation.

Conclusions

Lymphopenia was infrequent in our COVID-19 cohort; however, flow cytometric analysis revealed absolute T-cell count reduction in most cases. COVID-19 cases had significant APHA with monolobate neutrophils and plasmacytoid lymphocytes as compared to controls.
Y-site physical compatibility of hydrocortisone continuous infusions with admixtures used in critically ill patients
Authors: Foushee Jaime A , Meredith Pmichiaele , Fox Laura M , Wilder Alyson G
Published: June 2020

Purpose

Critically ill patients with septic shock often receive multiple intravenous medications, necessitating either the placement of separate lines for medication administration or administration of medications concurrently through a Y-site connector only where compatibility has been demonstrated. The purpose of this study was to examine the physical compatibility of hydrocortisone infusions and select intravenous medications through a simulated Y site.

Methods

The medications tested for simulated Y-site physical compatibility with hydrocortisone included acetaminophen, albumin, cefepime, ciprofloxacin, cisatracurium, doripenem, epinephrine, esomeprazole, ibuprofen, levofloxacin, levothyroxine, meropenem, and norepinephrine. Hydrocortisone in solution with 0.9% sodium chloride injection was combined with an equivalent volume of solutions of each test drug at maximum or commercially available concentrations used clinically in intensive care units, as appropriate. The samples were evaluated using turbidimetric measurements and examined visually against light and dark backgrounds to determine physical compatibility. Observations and analyses were completed over a one-hour period at 15-minute intervals beginning immediately after mixing. Each test was performed in triplicate.

Results

All study medications demonstrated visual and/or turbidimetric physical compatibility when combined with hydrocortisone in a simulated Y-site infusion. No medications demonstrated a visual physical incompatibility when combined with hydrocortisone.

Conclusion

Acetaminophen, albumin, cefepime, ciprofloxacin, cisatracurium, doripenem, epinephrine, esomeprazole, ibuprofen, levofloxacin, levothyroxine, meropenem, and norepinephrine exhibited physical compatibility with hydrocortisone via Y-site infusion.
Predicting human microbe–disease associations via graph attention networks with inductive matrix completion
Authors: Long Yahui , Luo Jiawei , Zhang Yu , Xia Yan
Published: June 2020

Motivation

human microbes play a critical role in an extensive range of complex human diseases and become a new target in precision medicine. In silico methods of identifying microbe–disease associations not only can provide a deep insight into understanding the pathogenic mechanism of complex human diseases but also assist pharmacologists to screen candidate targets for drug development. However, the majority of existing approaches are based on linear models or label propagation, which suffers from limitations in capturing nonlinear associations between microbes and diseases. Besides, it is still a great challenge for most previous methods to make predictions for new diseases (or new microbes) with few or without any observed associations.

Results

in this work, we construct features for microbes and diseases by fully exploiting multiply sources of biomedical data, and then propose a novel deep learning framework of graph attention networks with inductive matrix completion for human microbe-disease association prediction, named GATMDA. To our knowledge, this is the first attempt to leverage graph attention networks for this important task. In particular, we develop an optimized graph attention network with talking-heads to learn representations for nodes (i.e. microbes and diseases). To focus on more important neighbours and filter out noises, we further design a bi-interaction aggregator to enforce representation aggregation of similar neighbours. In addition, we combine inductive matrix completion to reconstruct microbe-disease associations to capture the complicated associations between diseases and microbes. Comprehensive experiments on two data sets (i.e. HMDAD and Disbiome) demonstrated that our proposed model consistently outperformed baseline methods. Case studies on two diseases, i.e. asthma and inflammatory bowel disease, further confirmed the effectiveness of our proposed model of GATMDA.

Availability

python codes and data set are available at: https://github.com/yahuilong/GATMDA.

Contact

luojiawei@hnu.edu.cn.
Webina: an open-source library and web app that runs AutoDock Vina entirely in the web browser
Authors: Kochnev Yuri , Hellemann Erich , Cassidy Kevin C , Durrant Jacob D
Published: June 2020

Motivation

Molecular docking is a computational technique for predicting how a small molecule might bind a macromolecular target. Among docking programs, AutoDock Vina is particularly popular. Like many docking programs, Vina requires users to download/install an executable file and to run that file from a command-line interface. Choosing proper configuration parameters and analyzing Vina output is also sometimes challenging. These issues are particularly problematic for students and novice researchers.

Results

We created Webina, a new version of Vina, to address these challenges. Webina runs Vina entirely in a web browser, so users need only visit a Webina-enabled webpage. The docking calculations take place on the user’s own computer rather than a remote server.

Availability and implementation

A working version of the open-source Webina app can be accessed free of charge from http://durrantlab.com/webina.

Supplementary information

Supplementary data are available at Bioinformatics online.
The Epigenetic Pacemaker: modeling epigenetic states under an evolutionary framework
Authors: Farrell Colin , Snir Sagi , Pellegrini Matteo
Published: June 2020

Epigenetic rates of change, much as evolutionary mutation rate along a lineage, vary during lifetime. Accurate estimation of the epigenetic state has vast medical and biological implications. To account for these non-linear epigenetic changes with age, we recently developed a formalism inspired by the Pacemaker model of evolution that accounts for varying rates of mutations with time. Here, we present a python implementation of the Epigenetic Pacemaker (EPM), a conditional expectation maximization algorithm that estimates epigenetic landscapes and the state of individuals and may be used to study non-linear epigenetic aging.

Availability and Implementation

The EPM is available at https://pypi.org/project/EpigeneticPacemaker/ under the MIT license. The EPM is compatible with python version 3.6 and above.
Sleep spindles are resilient to extensive white matter deterioration
Authors: Sanchez Erlan , Arbour Caroline , El-Khatib Héjar , Marcotte Karine , Blais Hélène , Baril Andrée-Ann , Bedetti Christophe , Descoteaux Maxime , Lina Jean-Marc , Gilbert Danielle , Carrier Julie , Gosselin Nadia
Published: June 2020

Sleep spindles are an essential part of non-rapid eye movement sleep, notably involved in sleep consolidation, cognition, learning and memory. These oscillatory waves depend on an interaction loop between the thalamus and the cortex, which relies on a structural backbone of thalamo-cortical white matter tracts. It is still largely unknown if the brain can properly produce sleep spindles when it underwent extensive white matter deterioration in these tracts, and we hypothesized that it would affect sleep spindle generation and morphology. We tested this hypothesis with chronic moderate to severe traumatic brain injury (n = 23; 30.5 ± 11.1 years old; 17 m/6f), a unique human model of extensive white matter deterioration, and a healthy control group (n = 27; 30.3 ± 13.4 years old; 21m/6f). Sleep spindles were analysed on a full night of polysomnography over the frontal, central and parietal brain regions, and we measured their density, morphology and sigma-band power. White matter deterioration was quantified using diffusion-weighted MRI, with which we performed both whole-brain voxel-wise analysis (Tract-Based Spatial Statistics) and probabilistic tractography (with High Angular Resolution Diffusion Imaging) to target the thalamo-cortical tracts. Group differences were assessed for all variables and correlations were performed separately in each group, corrected for age and multiple comparisons. Surprisingly, although extensive white matter damage across the brain including all thalamo-cortical tracts was evident in the brain-injured group, sleep spindles remained completely undisrupted when compared to a healthy control group. In addition, almost all sleep spindle characteristics were not associated with the degree of white matter deterioration in the brain-injured group, except that more white matter deterioration correlated with lower spindle frequency over the frontal regions. This study highlights the resilience of sleep spindles to the deterioration of all white matter tracts critical to their existence, as they conserve normal density during non-rapid eye movement sleep with mostly unaltered morphology. We show that even with such a severe traumatic event, the brain has the ability to adapt or to withstand alterations in order to conserve normal sleep spindles.
The Evidence-Based Sexual Abuse Prevention Program: Strong With Sam
Authors: Urbann Katharina , Bienstein Pia , Kaul Thomas
Published: June 2020

The present study was initiated to design and evaluate a sexual abuse prevention program for deaf and hard of hearing (DHH) children. This evidence-based prevention program is the first of its kind for DHH children. A total of 92 DHH children aged 8–12 years participated in the program “STARK mit SAM” (Strong with Sam, SmS), a program conducted in primary schools for DHH children in Germany. The program evaluation consisted of a pretest−posttest design. As per class, the subjects were assigned to either the experimental or the wait list control group. Participants from both groups were pretested for their knowledge about content related to the prevention of sexual abuse. The experimental group received the prevention program and both groups were posttested to examine the effects of the program. Additionally, the experimental group was tested again 6 months after the program. DHH children who participated in the SmS program showed a significant knowledge gain and a nonsignificant change in their anxiety. No significant factor affecting the children’s significant knowledge gain was found. SmS is an effective sexual abuse prevention program for DHH children, which can be offered without incurring anxiety in the children.
External validation of the N descriptor in the proposed tumour–node–metastasis subclassification for lung cancer: the crucial role of histological type, number of resected nodes and adjuvant therapy
Authors: Chiappetta Marco , Lococo Filippo , Leuzzi Giovanni , Sperduti Isabella , Petracca-Ciavarella Leonardo , Bria Emilio , Mucilli Felice , Filosso Pier Luigi , Ratto Giovanni Battista , Spaggiari Lorenzo , Facciolo Francesco , Margaritora Stefano
Published: June 2020

OBJECTIVES

Overlapping survival curves for N1b (multiple N1 stations), N2a2 (single N2 station + N1 involvement) and N2a1 (skip N2 metastasis) limit the current tumour–node–metastasis (TNM) node (N) subclassification for node involvement. We validated externally the proposed subclassification.

METHODS

Clinical records from a multicentric database comprising 1036 patients with pulmonary adenocarcinoma (ADC) or squamous cell carcinoma with N1/N2 involvement who underwent, from January 2002 to December 2014, complete lung resections were retrospectively reviewed. Patients were categorized according to the 8th TNM N subclassification proposal. Histological type, number of resected nodes (#RN) and adjuvant therapy (ADJ) were considered limiting factors.

RESULTS

No difference in the 5-year overall survival (-OS) was noted between N1b and N2a1 (49.6% vs 44.8%, P = 0.72); instead, the 5-year-OS was significantly improved in patients with squamous cell carcinoma (63% in N1b vs 30.7% in N2a1, P = 0.04). In patients with ADC, the 5-year-OS was better in those with N2a1 than with N1b (50.6% vs 37.5%, P = 0.09). When we compared N1b with N2a2, the 5-year-OS was statistically significant (49.6% vs 32.8%, P = 0.02); considering only patients with squamous cell carcinoma (63% vs 25.8%, P = 0.003), #RN >10 (63.2% vs 35.3%, P = 0.05) and without ADJ (56.4% vs 24.5%, P = 0.02), the 5-year-OS was significantly different. Differences were not significant for ADC, #RN <10 and ADJ. Finally, the 5-year-OS was statistically significant when we compared N2a1 with N2a2 of the total cohort (44.8% vs 32.8%, P = 0.04), in ADC (5-year-OS 50.6% vs 36.5%, P = 0.04) and #RN >10 (5-year-OS 49.8% vs 32.1%, P = 0.03) without ADJ.

CONCLUSIONS

Histological type, ADJ and #RN are relevant prognostic factors in N + non-small-cell lung cancer. Considering these results, we may better interpret the prognosis prediction limits of the proposed 8th TNM subclassification for the N descriptor.
Prevention and treatment of pulmonary congestion in patients undergoing venoarterial extracorporeal membrane oxygenation for cardiogenic shock
Authors: Lüsebrink Enzo , Orban Mathias , Kupka Danny , Scherer Clemens , Hagl Christian , Zimmer Sebastian , Luedike Peter , Thiele Holger , Westermann Dirk , Massberg Steffen , Schäfer Andreas , Orban Martin
Published: June 2020

Cardiogenic shock is still a major driver of mortality on intensive care units and complicates ∼10% of acute coronary syndromes with contemporary mortality rates up to 50%. In the meantime, percutaneous circulatory support devices, in particular venoarterial extracorporeal membrane oxygenation (VA-ECMO), have emerged as an established salvage intervention for patients in cardiogenic shock. Venoarterial extracorporeal membrane oxygenation provides temporary circulatory support until other treatments are effective and enables recovery or serves as a bridge to ventricular assist devices, heart transplantation, or decision-making. In this critical care perspective, we provide a concise overview of VA-ECMO utilization in cardiogenic shock, considering rationale, critical care management, as well as weaning aspects. We supplement previous literature by focusing on therapeutic issues related to the vicious circle of retrograde aortic VA-ECMO flow, increased left ventricular (LV) afterload, insufficient LV unloading, and severe pulmonary congestion limiting prognosis in a relevant proportion of patients receiving VA-ECMO treatment. We will outline different modifications in percutaneous mechanical circulatory support to meet this challenge. Besides a strategy of running ECMO at lowest possible flow rates, novel therapeutic options including the combination of VA-ECMO with percutaneous microaxial pumps or implementation of a venoarteriovenous-ECMO configuration based on an additional venous cannula supplying towards pulmonary circulation are most promising among LV unloading and venting strategies. The latter may even combine the advantages of venovenous and venoarterial ECMO therapy, providing potent respiratory and circulatory support at the same time. However, whether VA-ECMO can reduce mortality has to be evaluated in the urgently needed, ongoing prospective randomized studies EURO-SHOCK (NCT03813134), ANCHOR (NCT04184635), and ECLS-SHOCK (NCT03637205). These studies will provide the opportunity to investigate indication, mode, and effect of LV unloading in dedicated sub-analyses. In future, the Heart Teams should aim at conducting a dedicated randomized trial comparing VA-ECMO support with vs. without LV unloading strategies in patients with cardiogenic shock.