Zinc-doped hydroxyapatite and poly(propylene fumarate) nanocomposite scaffold for bone tissue engineering

Hydroxyapatite (HA) is a bioceramic material that shares similar crystal and chemical structures with inorganic components of the bone. However, HA lacks osteoinductive activity and has a brittle nature, making it challenging to apply for direct load-bearing bone applications. In this study, we used a wet chemical method to synthesize zinc-doped hydroxyapatite powders with different Zn/(Zn+Ca) molar ratios of 0, 0.025, 0.05, and 0.1. The corresponding Zn-HA was designated as HA, Zn2.5-HA, Zn5-HA, and Zn10-HA. The Zn-HA powders at 30 wt% were used to fabricate poly(propylene fumarate) (PPF)-based nanocomposite scaffolds (HA/PPF, Zn2.5-HA/PPF, Zn5-HA/PPF, and Zn10-HA/PPF). The physical properties of obtained scaffolds were examined by scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Live/dead cell viability assay showed that these scaffolds were biocompatible and supported excellent adhesion of MC3T3-E1 preosteoblast cells. Additionally, the proliferation of cells was detected at 1, 4, and 7 days on these scaffolds. Alkaline phosphatase (ALP) activity measurement and alizarin red staining showed good osteogenic differentiation and matrix mineralization for MC3T3-E1 cells growing on these scaffolds. Taken together, the results here indicate that Zn5-HA/PPF nanocomposite scaffolds are promising scaffold material for bone tissue engineering.

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Preparation of hydrophobic flat sheet membranes from PVDF-HFP copolymer for enhancing the oxygen permeance in nitrogen/oxygen gas mixture

In this study, poly(vinilydene fluoride-co-hexafluoropropylene)(PVDF-HFP) was used for preparation of hydrophobic membranes using non-solvent induced phase inversion(NIPS) technique. PVDF-HFP copolymer with concentrations of 10 wt% and 12 wt% was prepared to investigate the effect of polymer concentration on pore structure,morphology, hydrophobicity and performance of prepared membranes. Besides, the use of two coagulation baths with the effects of parameters such as coagulant time, polymer type and concentration, and the amount of nonsolvent were studied. The performance of prepared membranes was evaluated based on the permeability and selectivity of oxygen and nitrogen from a gas mixture of nitrogen/oxygen under operating conditions of feed flow rate(1–5 L·min~(-1)), inlet pressure to membrane module(0.1–0.5 MPa) and temperatures between 25 and 45 °C. The results showed that the use of two coagulation baths with different compositions of distillated water and isopropanol,coagulant time, polymer type and concentration, and the amount of non-solvent additive have the most effect on pore structure, morphology, thickness, roughness and crystallinity of fabricated membranes. Porosity ranges for the three fabricated membranes were determined, where the maximum porosity was 73.889% and the minimum value was 56.837%. Also, the maximum and minimum average thicknesses of membrane were 320.85 μm and115 μm. Besides, the values of 4.7504 × 10~(-7) mol· m~(-2)· s~(-1)· Pa~(-1), 0.525 and 902.126 nm were achieved for maximum oxygen permeance, O_2/N_2 selectivity and roughness, respectively.     

Thermal and rheological effects in a classical Graetz problem using a nonlinear Robertson-Stiff fluid model

The present article elaborates the Graetz problem for the Robertson-Stiff fluid model with imposed iso-thermal conditions. The closed-form expression of Robertson-Stiff fluid velocity is obtained. Employing the classical separation of variables approach, the energy equation of the said problem is reduced into an eigenvalue problem. The solution of the eigenvalue problem is developed numerically via the MATLAB built-in algorithm BVP4C. The constants appearing in series solutions are computed by Simpson's rule. The special case of this analysis with appropriate scaling is also applicable for the Bingham, power-law, and Newtonian fluid models. The impact of the dissipation function on Nusselt numbers and mean temperature is also considered. The pictorial representation of average temp7erature and Nusselt number are discussed in the presence of the plug radius, power-law index, and Brinkman number. It is observed that the presence of the plug radius and power-law index delay the prevalence of fully developed conditions for the Nusselt number. Moreover, the local Nusselt number for channel confinement attains higher values as compared with tube confinement. The present investigation has numerous applications in the field of engineering, nanotechnology, biomedical sciences, and development of several thermal types of equipment or microfluidic devices.     

Investigation of functional core-rim composite part production by inserted powder injection moulding

In this study, the use of Cu and Ni interlayers have been investigated for functional core-rim composite part production with WC-Co 9?wt-% feedstock/steel. For this purpose, different experiments have been performed and joining condition, shear strength and microstructure of the intermediate region have been examined. It has been found that AISI 4340 insert/WC-Co have been joined and 85.8?MPa shear strength achieved, but high speed steel insert has not joined. Moreover, it has been determined that better results are obtained with Ni interlayer. Under the same conditions, when the 40?µm Ni interlayer has been used between AISI 4340 core and WC-Co rim, shear strength has been increased approximately twice and has been 162.7?MPa.     

Performance Evaluation of Supervised Machine Learning Techniques for Efficient Detection of Emotions from Online Content

Emotion detection from the text is a challenging problem in the text analytics. The opinion mining experts are focusing on the development of emotion detection applications as they have received considerable attention of online community including users and business organization for collecting and interpreting public emotions. However, most of the existing works on emotion detection used less efficient machine learning classifiers with limited datasets, resulting in performance degradation. To overcome this issue, this work aims at the evaluation of the performance of different machine learning classifiers on a benchmark emotion dataset. The experimental results show the performance of different machine learning classifiers in terms of different evaluation metrics like precision, recall ad f-measure. Finally, a classifier with the best performance is recommended for the emotion classification.     

Evaluating the Efficiency of CBAM-Resnet Using Malaysian Sign Language

The deaf-mutes population is constantly feeling helpless when others do not understand them and vice versa. To fill this gap, this study implements a CNN-based neural network, Convolutional Based Attention Module (CBAM), to recognise Malaysian Sign Language (MSL) in videos recognition. This study has created 2071 videos for 19 dynamic signs. Two different experiments were conducted for dynamic signs, using CBAM-3DResNet implementing ‘Within Blocks’ and ‘Before Classifier’ methods. Various metrics such as the accuracy, loss, precision, recall, F1-score, confusion matrix, and training time were recorded to evaluate the models’ efficiency. Results showed that CBAM-ResNet models had good performances in videos recognition tasks, with recognition rates of over 90% with little variations. CBAM-ResNet ‘Before Classifier’ is more efficient than ‘Within Blocks’ models of CBAM-ResNet. All experiment results indicated the CBAM-ResNet ‘Before Classifier’ efficiency in recognising Malaysian Sign Language and its worth of future research.     

Miniaturized on‐body antenna for small and wearable brain microwave imaging systems

A miniaturized inset‐fed on‐body meandered bowtie antenna designed for brain microwave imaging systems is presented in this article. The proposed on‐body antenna can contribute to the realization of a wearable and portable brain microwave imaging system. The size of 18 × 18 mm² is achieved at a frequency range of 0.75 to 4 GHz by the simultaneous use of self‐complementary structures and meandered lines. The frequency band is a trade‐off between penetration depth and spatial resolution. The proposed antenna performance was studied at different positions on the human head voxel model in terms of several parameters such as reflection coefficient, near‐field directivity, and fidelity factor. In addition, the antenna bandwidth was surveyed on several volunteers using a wearable measurement setup. It has been found that the averages of measured reflection coefficients in different scenarios are in good agreement with the corresponding simulation results, and the antenna shows stable performance under different practical situations. The proposed antenna takes advantage of a small footprint and body matching, which make it an eligible choice for compact, portable, and wearable head microwave imaging systems.     

Robust audio watermarking algorithm based on DWT using Fibonacci numbers

Multimedia Tools and Applications - This paper presents a blind and robust audio watermarking algorithm developed based on Fibonacci numbers properties and the discrete wavelet transform (DWT)...