Synthesis,characterisation and potential biomedical applications of magnetic core–shell structures: carbon‐, dextran‐, SiO2 ‐ and ZnO‐coated Fe3 O4 nanoparticles

Due to the strong effect of nanoparticles'' size and surface properties on cellular uptake and bio‐distribution, the selection of coating material for magnetic core–shell nanoparticles (CSNPs) is very important. In this study, the effects of four different biocompatible coating materials on the physical properties of Fe₃ O₄ (magnetite) nanoparticles (NPs) for different biomedical applications are investigated and compared. In this regard, magnetite NPs are prepared by a simple co‐precipitation method. Then, CSNPs including Fe₃ O₄ as a core and carbon, dextran, ZnO (zincite) and SiO₂ (silica) as different shells are synthesised using simple one‐ or two‐step methods. A comprehensive study is carried out on the prepared samples using X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy and Fourier transform infrared spectroscopy analyses. According to the authors'' findings, it is suggested that carbon‐ and dextran‐coated magnetite NPs with high M _s have great potential in the application of magnetic resonance imaging contrast agents. Moreover, silica‐coated magnetite NPs with high coercivity are potentially suitable candidates for hyperthermia and ZnO‐coated Fe₃ O₄ is potentially suitable for photothermal therapy.Inspec keywords: iron compounds, carbon, silicon compounds, zinc compounds, nanomedicine, biomedical materials, nanofabrication, nanoparticles, magnetic particles, coatings, X‐ray diffraction, magnetometry, transmission electron microscopy, Fourier transform spectra, infrared spectra, biomedical MRI, hyperthermia, radiation therapyOther keywords: biomedical applications, magnetic core‐shell nanoparticles, CSNP, cellular uptake, biodistribution, coating material, biocompatible coating materials, co‐precipitation, dextran, zincite, silica, X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy, Fourier transform infrared spectroscopy, magnetic resonance imaging contrast agents, hyperthermia, photothermal therapy, SiO₂ ‐Fe₃ O₄ , ZnO‐Fe₃ O₄      

Gentamicin‐gold nanoparticles conjugate: a contrast agent for X‐ray imaging of infectious foci due to Staphylococcus aureus

There is no optimal imaging method for the detection of unknown infectious foci in some diseases. This study introduces a novel method in X‐ray imaging of infection foci due to Staphylococcus aureus by developing a contrast agent based on gold nanoparticles (GNPs). GNPs in spherical shape were synthesised by the reduction of tetrachloroauric acid with sodium citrate. Then gentamicin was bound directly to citrate functionalised GNPs and the complex was stabilised by polyethylene glycol. The interaction of gentamicin with GNPs was confirmed by ultraviolet–visible and Fourier transform infrared spectroscopies. The stability of complex was studied in human blood up to 6 h. The stability of conjugate was found to be high in human blood with no aggregation. The biodistribution study showed localisation of gentamicin–GNPs conjugate at the site of Staphylococcal infection. The infection site was properly visualised in X‐ray images in mouse model using the gentamicin–GNPs conjugate as a contrast agent. The results demonstrated that one may consider the potential of new nanodrug as a contrast agent for X‐ray imaging of infection foci in human beings which needs more investigations.Inspec keywords: drugs, nanomedicine, nanoparticles, nanofabrication, diagnostic radiography, microorganisms, diseases, polymers, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, goldOther keywords: gentamicin‐gold nanoparticle conjugate, contrast agent, X‐ray imaging, Staphylococcus aureus, disease, tetrachloroauric acid reduction, sodium citrate, polyethylene glycol, ultraviolet‐visible spectroscopy, Fourier transform infrared spectroscopy, human blood, Staphylococcal infection, X‐ray images, murine model, nanodrug     

The Mimo Predictive Pid Controller Design

This paper is concerned with the design of Multi‐Inputs and Multi‐Outputs (MIMO) predictive PID controllers, which have similar performance to that obtainable from model‐based predictive controllers. A new PID control structure is defined which incorporates the prediction of future outputs and uses future set point. A method is proposed to calculate the optimal values of the PID gains from generalised predictive control results. A decentralized version of the predictive PID controllers is presented and the stability of the closed loop system is studied. Simulation studies demonstrate the superior performance of the proposed controller compared with a conventional PID controller. The results are also compared with generalised predictive control solutions.     

Effects on engineering properties of cement-treated road base with slow setting bitumen emulsion

This study investigated the effects of the type and amount of Portland cement and cationic slow setting bitumen emulsion additives on the short- and long-term performance of road-based properties using laboratory mechanistic evaluation. Stabilised specimens with Portland cement (0–6%) and bitumen emulsion (0–6%) were compacted, cured for 7, 28 and 60 days; and finally subjected to different stress sequences to study their unconfined compressive strength, indirect tensile resident modulus and indirect tensile strength tests. The durability of stabilised soil specimens was investigated by conducting wetting and drying (WD) cycling test on 7 days cured specimens. The results showed the added 4% portland cement–3% bitumen emulsion mix was ideal and produced a 179.4% reduction in the water absorption and permeability, 256.3% reduction in volume changes and 211.95% reduction in weight losses relative to a 4% cement sample. This paper presents the findings of a correlation that was conducted using non-linear regression analysis regarding the influences of the affected variables in order to establish models to predict the mixture strength parameters.     

Study of Magnetic Abrasive Finishing for AISI321 Stainless Steel

In recent years, magnetic abrasive finishing (MAF) has become a reliable unconventional technology among researchers in industries due to need for the surface roughness reduction in metals. In this study, experiments based on influential parameters in the MAF process including rotational speed, working gap, and abrasive particle size were designed and conducted in the full factorial method in order to achieve the optimum parameters in finishing of steel AISI 321. A combination of silicon carbide (SiC), iron (Fe), and oil (SAE40) was utilized as magnetic abrasive tool. Prior to the experiments, the surface of the workpiece was abraded to the lowest value of roughness in order to obtain accurate results through the procedure. In general, the results indicate that the parameters of working gap, rotational speed, and abrasive particle size influence the surface roughness from the most to the least, respectively. Indeed, the minimum surface roughness is obtained through working gap of 1 mm, workpiece rotational speed of 500 rpm, and abrasive particle size of 100 mesh, with 50% improvement compared with initial surface roughness. Finally, the more involved parameters deviate from optimum values, the worse results are obtained compared with optimum acquired consequences.     

Correction to: Probabilistic elderly person’s mood analysis based on its activities of daily living using smart facilities

Pattern Analysis and Applications -     

Graphene Liquid Cells Assembled through Loop‐Assisted Transfer Method and Located with Correlated Light‐Electron Microscopy

Graphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high‐resolution, real‐time imaging of dynamic processes in water. Large‐scale implementation, however, is prevented by major difficulties in reproducing GLC fabrication. Here, a high‐yield method is presented to fabricate GLCs under millimeter areas of continuous graphene, facilitating efficient GLC formation on a TEM grid. Additionally, GLCs are located on the grid using correlated light‐electron microscopy (CLEM), which reduces beam damage by limiting electron exposure time. CLEM allows the acquisition of reliable statistics and the investigation of the most common shapes of GLCs. In particular, a novel type of liquid cell is found, formed from only a single graphene sheet, greatly simplifying the fabrication process. The methods presented in this work—particularly the reproducibility and simplicity of fabrication—will enable future application of GLCs for high‐resolution dynamic imaging of biomolecular systems.     

SAOSA: Stable Adaptive Optimization for Stacked Auto-encoders

Neural Processing Letters - The stacked auto-encoders are considered deep learning algorithms automatically extracting meaningful unsupervised features from the input data using a hierarcfhical...     

A Multi-Objective Risk-Based Game Theoretic Approach to Reservoir Operation Policy in Potential Future Drought Condition

In this paper, by using the concept of Conditional Value at Risk (CVaR), a Leader-Follower game (LFG) based multi-objective optimization model is developed to determine the optimum 12-month operation policy of a reservoir in potential future dry periods. The minimization of CVaRs of storage loss and agricultural and environmental deficits along with maximization of planned allocation to agricultural sector are considered as leader’s objectives, while the followers try to maximize their share of water rights using Nash bargaining (NB) method. This framework is then used to model the operation policy of Dorudzan basin in Fars province, southwestern Iran. Water demand and daily climate data in the period of 2003 to 2015 for this basin, as well as future projections from fifteen IPCC-AR4 global circulation models (GCMs) for 2018–2030 under A2, B1 and A1B emission scenarios are considered to evaluate future dam operation policies. Future projections are downscaled using the LARS-WG model, which then feeds the HMETS watershed model to simulate the corresponding reservoir inflow time-series. Thereafter, three-hundred 12-month rainfall, evaporation and inflow time series with least inflow volume are used as input for the optimization model, which is solved using NSGA-II and GA algorithms. The results show while the model can determine the operation policy that keeps the associated risks in the acceptable range, it can satisfy the followers demands with respect to the available resources. The results also show that the agricultural sector of the study area can be hugely affected by potential future droughts.

     

Scale-dependent dynamic stability analysis of nanowire-fabricated nanotweezers

Dynamic stability analysis of nanowire-fabricated nanotweezers is examined in this paper using a new nonlinear model. A novel size dependent model based on the strain gradient theory (SGT) and the Gurtin–Murdoch elasticity (GME) is presented for simulating the simultaneous effects of scale-dependent phenomena (i.e. microstructure dependency and surface energies). Moreover, the impacts of rare field gas damping, structural damping, intermolecular force and Casimir attraction are included in the proposed model. An analytical solution is developed for investigating the dynamic instability. It is established that the proposed model exhibit significant scale-dependence effect on the stability characteristics of nanotweezers.