Development of new ionic gelation strategy: Towards the preparation of new monodisperse and stable hyaluronic acid/β-cyclodextrin-grafted chitosan nanoparticles as drug delivery carriers for doxorubicin

In the present study, β-cyclodextrin-grafted chitosan nanoparticles (β-CD-g-CS NPs) were prepared using a new ionic gelation strategy involving a synergistic effect of NaCl (150 mmol/L), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES, 10 mmol/L), and water bath sonication. This new strategy afforded smaller and more monodisperse β-CD-g-CS NPs vs. the classical ionic gelation method. New HA/β-CD-g-CS NPs were also prepared using the above-mentioned strategy by adding hyaluronic acid (HA) to the β-CD-g-CS copolymer at different weight ratios until the ZP values conversion. The best result was obtained with the weight ratio of w(HA):w(β-CD-g-CS) = 2:1 and furnished new spherical and smooth HA/β-CD-g-CS NPs. Furthermore, the stability of β- CD-g-CS NPs and HA/β-CD-g-CS NPs at 4°C in physiological medium (pH 7.4) was compared for 3 weeks period and showed that HA/β-CD-g-CS NPs were more stable all maintaining their monodispersity and high negative ZP values compared to β-CD-g-CS NPs. Finally, preliminary study of HA/β-CD-g-CS NPs as carrier for the controlled release of the anticancer drug doxorubicin was investigated. These new HA/β-CD-g-CS NPs can potentially be used as drug delivery and targeting systems for cancer treatment.     

Endotoxins and inflammation in hemodialysis patients

Long‐term endotoxin challenge may promote frequent complications in dialysis patients, namely malnutrition, chronic inflammation, and atherosclerosis, which are recognized as the so‐called MIA syndrome. Circulating soluble vascular cell adhesion molecule‐1 (sVCAM‐1) levels may be used to determine the stage of atherosclerosis. This study aimed to assess endotoxin level in hemodialysis (HD) patients and its role in inducing inflammation. The study was conducted on 50 HD patients, chosen from four dialysis centers in Alexandria. Serum blood samples were collected for the determination of albumin and C‐reactive protein (CRP), and whole blood samples were used for the measurement of hemoglobin level. A heparinized whole blood sample was taken postdialysis for endotoxin assay by limulus amebocyte lysate test, and in addition to sVCAM‐1 was estimated using enzyme‐linked immunosorbent assay. The mean endotoxin level was 76.30 pg/mL;80% exhibited values higher than 60 pg/mL. Half the studied patients had CRP values that exceeded the upper limit of the laboratory reference range (<6.0 mg/L). A statistically significant correlation was found between endotoxin and CRP levels (r = 0.47, P = 0.001). The mean pre‐HD level of VCAM was 1851.00 ng/mL, while the mean post‐HD level was 2829.00 ng/mL with statistically significant correlation (r = 0.354, P = 0.012) and it also correlated significantly with endotoxin as well as CRP levels. Endotoxemia may play an important role in the aggravation of endothelial dysfunction in HD patients as indicated by the post‐HD rise in sVCAM‐1.     

First-Principles Study of Lattice Dynamics and Thermal Properties of Alkaline-Earth Metal Nitrides CaN,SrN, and BaN

We have performed first-principles calculations to investigate the structural, electronic, magnetic, lattice dynamics, and thermodynamic properties of ferromagnetic alkaline earth metal nitrides CaN, SrN, and BaN in the rocksalt structure using the plane-wave pseudopotential approach to the density functional theory within local density and generalized gradient approximations for the exchange and correlation potential. The linear response to the density functional theory allowed us to calculate the phonon dispersion spectra for these compounds. We reported also the results on thermodynamic properties as a function of temperature calculated by using the quasiharmonic approximation.     

Transmission of nanoscale information-based neural communication-aware ligand–receptor interactions

Neural Computing and Applications - In this paper, we develop an analytical framework for modeling the transmission of nanoscale information in nanonetwork-based molecular communication and aware...     

Adaptive Fault Tolerant Control of Multi-time-scale Singularly Perturbed Systems

This paper studies the fault tolerant control, adaptive approach, for linear time-invariant two-time-scale and three-time-scale singularly perturbed systems in presence of actuator faults and external disturbances. First, the full order system will be controlled using ε-dependent control law. The corresponding Lyapunov equation is ill-conditioned due to the presence of slow and fast phenomena. Secondly, a time-scale decomposition of the Lyapunov equation is carried out using singular perturbation method to avoid the numerical stiffness. A composite control law based on local controllers of the slow and fast subsystems is also used to make the control law ε-independent. The designed fault tolerant control guarantees the robust stability of the global closed-loop singularly perturbed system despite loss of effectiveness of actuators. The stability is proved based on the Lyapunov stability theory in the case where the singular perturbation parameter is sufficiently small. A numerical example is provided to illustrate the proposed method.     

Fast mode decision algorithm for H.264/SVC enhancement layer

Scalable video coding (SVC) has been standardized to extend the capabilities of the H.264 advanced video coding (AVC). The SVC can compress several video sequences of various resolutions as a single bit-stream. In the SVC enhancement layer, for Joint Scalable Video Model (JSVM) software implementation, an exhaustive mode decision process based on the base layer mode predictions is performed to obtain the best mode for each macroblock (MB). This technique may achieve a higher coding efficiency; however, it induces a significant computational complexity in the encoding engine. In order to speedup the SVC encoder, a fast mode decision algorithm was proposed in this paper. In other words, our aim was to decrease the number of candidate modes to reduce the computational complexity and maintain the same level of coding efficiency, this approach used the spatial and temporal correlation between MB situated at the enhancement layer and its co-located MB at the base layer. Our statistical analyses were made using several HD sequences with different motion characteristics. Experimental results show a significant improvement in terms of time encoding which is a major constraint for any real-time implementation. However, this gain is accompanied with an acceptable loss in video quality and a tolerable bit rate increase for most media supports. In fact, our proposed algorithm permits a major improvement that can reach up to 64.9 % in terms of computational effort. This gain will induce an average loss yield to 10.5 or 13.87 % that is comparable to the 13.12 % of the He Li’s algorithm with an acceptable loss in terms of subjective video quality.     

Intelligent Open Switch Fault Detection for Power Converter in Wind Energy System

This paper proposes a simple and fast fuzzy logic-based open switch fault detection method for rotor side converter (RSC) in doubly fed induction generator (DFIG) wind turbine system. In the proposed scheme, only the mean values of the three-phase rotor currents are used to identify the power switch in which the open-circuit fault has occurred.

The wind energy conversion system model developed for the design and evaluation of the proposed fault detection technique including three principal controls. the first control ensure the regulation of the electromagnetic torque and the reactive stator power (named Rotor Side Converter (RSC) control), the second regulates the DC-link voltage at the desired level (named Grid Side Converter (GSC) control) and in order to achieve maximum power at any wind speed condition a maximum power point tracking (MPPT) control strategy has been used. The simulation model was developed in MATLAB/Simulink environment. The results show that the proposed fault detection scheme is able to rapidly and effectively identify open switch faults among other fault types in a time less than one period.     

Analysis of native biological surfaces using a 100 kV massive gold cluster source

In the present work, the advantages of a new, 100 kV platform equipped with a massive gold cluster source for the analysis of native biological surfaces are shown. Inspection of the molecular ion emission as a function of projectile size demonstrates a secondary ion yield increase of ~100× for 520 keV Au(400)(4+) as compared to 130 keV Au(3)(1+) and 43 keV C(60). In particular, yields of tens of percent of molecular ions per projectile impact for the most abundant components can be observed with the 520 keV Au(400)(4+) probe. A comparison between 520 keV Au(400)(4+) time-of-flight-secondary ion mass spectrometry (TOF-SIMS) and matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) data showed a similar pattern and similar relative intensities of lipid components across a rat brain sagittal section. The abundant secondary ion yield of analyte-specific ions makes 520 keV Au(400)(4+) projectiles an attractive probe for submicrometer molecular mapping of native surfaces.     

Effect of some operating variables on the flotation of aluminium particles

The effects of impeller speed, air flow rate, cell concentration, agitator size and cell volume on the recovery of aluminium particles have been studied in a KHD Humboldt Wedge AG machine, using alkyl benzene sodium sulphonate paste as collector and pine oil as frother. The recovery yield increased with increasing impeller speed, air flow rate, cell concentration and cell volume, up to a certain range, whereafter it decreased. A decrease in the recovery yield was observed on increasing the agitator size. A mathematical model has been developed to correlate percentage recovery with the above variables.     

Spectral coded phase bipolar OCDMA technological implementation thanks to low index modulation filters

Telecommunication Systems - Optical code division multiple access (OCDMA) systems are attracting an increasing interest in optical fiber communication. This is due to the various advantages that...