On‐Chip Fabrication of Paclitaxel‐Loaded Chitosan Nanoparticles for Cancer Therapeutics

The use of solvent‐free microfluidics to fine‐tune the physical and chemical properties of chitosan nanoparticles for drug delivery is demonstrated. Nanoparticle self‐assembly is driven by pH changes in a water environment, which increases biocompatibility by avoiding organic solvent contamination common with traditional techniques. Controlling the time of mixing (2.5–75 ms) during nanoparticle self‐assembly enables us to adjust nanoparticle size and surface potential in order to maximize cellular uptake, which in turn dramatically increases drug effectiveness. The compact nanostructure of these nanoparticles preserves drug potency better than previous nanoparticles, and is more stable during long‐term circulation at physiological pH. However, when the nanoparticles encounter a tumor cell and the associated drop in pH, the drug contents are released. Moreover, the loading efficiency of hydrophobic drugs into the nanoparticles increases significantly from previous work to over 95%. The microfluidic techniques used here have applications not just for drug‐carrying nanoparticle fabrication, but also for the better control of virtually any self‐assembly process.     

Influence of decelerating flow on incipient motion of a gravel-bed stream

An experimental study on incipient motion of gravel-bed streams under steady-decelerating flow is presented. Experiments were carried out in a flume with two median grain sizes, d ₅₀ = 16.7 mm for a fixed-bed case and d ₅₀ = 8 mm for a mobile bed case. In addition, an effort is made to determine a simplified method for the estimation of bed shear stress in decelerating flow over fixed and mobile beds for use in field situations. From the observation of eleven fixed-bed and nine mobile-bed velocity profiles, it is revealed that the parabolic law method (PLM) and the Reynolds stress method are comparable for estimation of shear velocity in general. Also, the results show that the shear stress distribution adopts a convex form over fixed and mobile beds. Due to this form the critical Shields parameter value for decelerating flow is less than the reported values in literature. This paper supports Buffington & Montgomery (1997) statement that less emphasis should be given on choosing a universal shields parameter, and more emphasis should be given on choosing defendable values based on flow structure.     

A New Method for Modeling of Initiation and Propagation of Delamination Between [0/θ<Superscript>o</Superscript>] Layers of Laminated Composites

In this article, initiation and propagation of delamination of a double cantilevered beam (DCB) is studied. The delamination of DCB specimen occurs between 0 ^o and θ ⁰ layers. Due to damage induced, during the loading, in the matrix of θ ⁰ layer, virtual crack closure technique (VCCT) as a well known method for simulation of initiation and propagation of the delamination for DCB is not able to model the propagation of delamination properly. To overcome this shortcoming, the stiffness of the damaged θ ⁰ layer is decreased with a developed technique in this study. The stiffness reduction technique (SR) is introduced in this paper to model the induced cracks in the matrix of the θ ⁰ layer. Then the stiffness reduction technique is coupled with the critical length parameter. The presented method is called stiffness reduction—critical length (SR-CL) method. By using SR-CL method, initiation and propagation of delamination for a [ ( 0₂^o/90^o )₆/0₂^o//q^o/( 0₂^o/90^o )₆/0₂^o ] \left[ {{{\left( {0_2^o/{{90}^o}} \right)}_6}/0_2^o//{\theta^o}/{{\left( {0_2^o/{{90}^o}} \right)}_6}/0_2^o} \right] configuration in which θ = 0^o, 22.5^o, 45^o, 67.5^o, 90^o and for a cross ply laminate (0°/90°) ₁₂ are modeled. The obtained results are in very good agreements with experimental data.     

Inulin addition to yoghurt: Prebiotic activity,health effects and sensory properties

Health and technical aspects of inulin have led to its wide applications in the food industry. Yoghurt is a cultured food with beneficial nutritional value that has advantageous effects in combination with inulin, for example reduction in fat content, improving the functions of the intestinal system and technical and textural influences. In this review, the physicochemical and health properties of inulin are described and also its use as a functional ingredient in yoghurt production is investigated. Also, the ability of inulin to increase probiotic viability and its influence on texture and flavour quality of yoghurt are discussed.     

Lamivudine‐conjugated and efavirenz‐loaded G2 dendrimers: Novel anti‐retroviral nano drug delivery systems

Infection with human immunodeficiency virus (HIV)‐1 causes immunological disorders and death worldwide which needs to be further assisted by novel anti‐retroviral drug delivery systems. Consequently, finding newer anti‐retroviral pharmaceuticals by using biocompatible, biodegradable nanomaterials comprising a nanoparticle as core and a therapeutic agent is of high global interest. In this experiment, a second generation of a negatively charged nano‐biopolymer linear globular G2 dendrimer was carefully conjugated and loaded with well‐known anti‐HIV drugs lamivudine and efavirenz, respectively. They were characterised by a variety of analytical methods such as Zetasizer, Fourier‐transform infrared spectroscopy, elemental analysis and liquid chromatography‐mass spectroscopy. Additionally, conjugated lamivudine and loaded efazirenz with globular PEGylated G2 dendrimer were tested on an HEK293 T cell infected by single‐cycle replicable HIV‐1 virion and evaluated using XTT test and HIV‐1 P24 protein load. The results showed that lamivudine‐conjugated G2 significantly decreased retroviral activity without any cell toxicity. This effect was more or less observed by efavirenz‐loaded G2. These nano‐constructs are strongly suggested for further in vivo anti‐HIV assays.     

A cloud computing framework for analysis of agricultural big data based on Dempster–Shafer theory

The Journal of Supercomputing - This paper aims to extract optimal location for cultivating orange trees. In order to reach this goal, a combination of Dempster-Shafer theory (DST) and cloud...     

Microstructural and diametral tensile strength evaluation of the zirconia-mullite composite

The purpose of the current research was to investigate the effect of duration of the mechanical activation process of starting materials on Vickers micro-hardness and diametral tensile strength of zirconia-mullite composites. Zirconia-mullite composites with 1:1?M ratio were fabricated by sintering of the mechanically activated kaolinite, gibbsite, and zircon powder mixture as inexpensive and convenient starting materials. Results of dynamic light scattering analysis showed that the mean particle size of the starting powders was reduced from 2.5?µm to 80?nm after 72?h of the mechanical activation process. X-ray diffraction analysis showed that zirconia and mullite were crystallized after 2?h thermal treatment at 1550?°C. Based on the semi-quantification results of X-ray diffraction patterns, increasing the duration of the milling process from 6 to 72?h had a positive effect on improving the amount of tetragonal zirconia in the final matrix. Scanning electron microscopy results revealed a fine and homogeneous distribution of zirconia particles in the mullite matrix after 72?h of the mechanical activation process. Increasing the duration of milling process from 6?h to 72?h had a remarkable effect in increasing the diametral tensile strength values from 30 to 220?MPa. Vickers micro-hardness values were also enhanced considerably from 7.30 to 11.12?GPa by increasing the milling time.     

Effects of organically modified nanoclay on the transport properties and electrochemical performance of acid‐doped polybenzimidazole membranes

Nanocomposite polyelectrolyte membranes based on phosphoric acid (H₃PO₄) doped polybenzimidazoles (PBIs) with various loading weights of organically modified montmorillonite (OMMT) were prepared and characterized for direct methanol fuel cell (DMFC) applications. X‐ray diffraction analysis revealed the exfoliated structure of OMMT nanolayers in the polymeric matrices. An H₃PO₄–PBI/OMMT membrane composed of 500 mol % doped acid and 3.0 wt % OMMT showed a membrane selectivity of approximately 109,761 in comparison with 40,500 for Nafion 117 and also a higher power density (186 mW/cm²) than Nafion 117 (108 mW/cm²) for a single‐cell DMFC at a 5M methanol feed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of nanocomposite polyelectrolyte membranes based on Nafion ionomer and nanocrystalline hydroxyapatite

In this study nanocrystalline hydroxyapatite (nHA) was synthesized and characterized by means of FT-IR, XRD and TEM techniques and a series of proton exchange membranes based on Nafion^® and nHA were fabricated via solvent casting method. Thermogravimetric analysis confirmed thermal stability enhancement of the Nafion^® nanocomposite due to the presence of nHA nanopowder. SAXS and TEM analyses confirmed the incorporation of nHA into ionic phase of Nafion^®. Furthermore, the incorporation of elliptical nHA into the Nafion^® matrix improved proton conductivity of the resultant polyelectrolyte membrane up to 0.173 S cm⁻¹ at 2.0 wt% of nHA loading compared to that of 0.086 S cm⁻¹ for Nafion^® 117. Also, the inclusion of nHA nanoparticles into nanocomposite membranes resulted in a significant reduction of methanol permeability and crossover in comparison with pristine Nafion^® membranes. Membrane selectivity parameter of the nanocomposites at 2.0 wt% nHA was calculated and found to be 106,800 S s cm⁻³, which is more than two times than that of Nafion^® 117. Direct methanol fuel cell tests revealed that Nafion^®/nHA nanocomposite membranes were able to provide higher fuel cell efficiency and also better electrochemical performance in both low and high concentrations of methanol feed. Thus, the current study shows that nHA enhances the functionality of Nafion^® as fuel cell membranes.     

Multiresolution,perceptual and vector quantization based video codec

This paper presents a novel Multiresolution, Perceptual and Vector Quantization (MPVQ) based video coding scheme. In the intra-frame mode of operation, a wavelet transform is applied to the input frame and decorrelates it into its frequency subbands. The coefficients in each detail subband are pixel quantized using a uniform quantization factor divided by the perceptual weighting factor of that subband. The quantized coefficients are finally coded using a quadtree-coding algorithm. Perceptual weights are specifically calculated for the centre of each detail subband. In the inter-frame mode of operation, a Displaced Frame Difference (DFD) is first generated using an overlapped block motion estimation/compensation technique. A wavelet transform is then applied on the DFD and converts it into its frequency subbands. The detail subbands are finally vector quantized using an Adaptive Vector Quantization (AVQ) scheme. To evaluate the performance of the proposed codec, the proposed codec and the adaptive subband vector quantization coding scheme (ASVQ), which has been shown to outperform H.263 at all bitrates, were applied to six test sequences. Experimental results indicate that the proposed codec outperforms the ASVQ subjectively and objectively at all bit rates.