Synthesis of Silver Nanoparticles and Exhaustion on Cotton Fabric Simultaneously Using Laser Ablation Method

ABSTRACT

In this experimental research, the silver nanoparticles were synthesized on cotton fabric using laser ablation method in the same bath. Also the effects of the size of silver nanoparticles (NPs) on the structural and antibacterial properties of silver NP-coated cotton fabric have been investigated experimentally. A pulsed laser beam was used for synthesis of Ag NPs on cotton fabric. Pulses of a Q-switched Nd:YAG laser of 1064 nm wavelengths at 7 ns pulse width and different fluencies was employed to irradiate the Ag target in deionized water in the presence of cotton fabric. Four samples were prepared using different laser fluencies. The amount, size, morphology, and structure of produced NPs were studied using their spectrum in the range of UV to IR, and scanning electron microscopy methods. Fabrics were polluted by gram-positive Staphylococcus aureus bacteria. The colony counting method was used to investigate the antibacterial activity of prepared cotton samples. Results show that laser ablation for synthesis of Ag nanoparticles on cotton fabric is an inexpensive fast method for producing antibacterial fabrics.     

Estimating Young's modulus of zona pellucida by micropipette aspiration in combination with theoretical models of ovum

The zona pellucida (ZP) is the spherical layer that surrounds the mammalian oocyte. The physical hardness of this layer plays a crucial role in fertilization and is largely unknown because of the lack of appropriate measuring and modelling methods. The aim of this study is to measure the biomechanical properties of the ZP of human/mouse ovum and to test the hypothesis that Young''s modulus of the ZP varies with fertilization. Young''s moduli of ZP are determined before and after fertilization by using the micropipette aspiration technique, coupled with theoretical models of the oocyte as an elastic incompressible half-space (half-space model), an elastic compressible bilayer (layered model) or an elastic compressible shell (shell model). Comparison of the models shows that incorporation of the layered geometry of the ovum and the compressibility of the ZP in the layered and shell models may provide a means of more accurately characterizing ZP elasticity. Evaluation of results shows that although the results of the models are different, all confirm that the hardening of ZP will increase following fertilization. As can be seen, different choices of models and experimental parameters can affect the interpretation of experimental data and lead to differing mechanical properties.     

Multiple sperm tracking in microscopic videos using modified GM-PHD filter

This paper presents a method for simultaneous tracking of multiple sperms using modified Gaussian mixture probability hypothesis density (GM-PHD) filter. In order to track sperms with spurious motion, a modified model is presented to adapt the GM-PHD filter for nonlinear dynamic movement of sperms. Furthermore, the “pruning” step in the GM-PHD filter is modified to handle situations like occlusion or closely moving targets. Our experiments demonstrate more effectivity of the proposed method in terms of sperms’ occlusion handling and trajectory extraction compared to the conventional GM-PHD filter. In particular, the new method performs well in managing the labels of occluded sperms after separation and in tracking of temporarily disappeared sperms when they emerge again in the tracking space.