Palmprint identification refers to searching in a database for the palmprint template, which is from the same palm as a given palmprint input. The identification process involves preprocessing, feature extraction, feature matching and decision-making. As a key step in the process, in this paper, we propose a new feature extraction method by converting a palmprint image from a spatial domain to a frequency domain using Fourier Transform. The features extracted in the frequency domain are used as indexes to the palmprint templates in the database and the searching process for the best match is conducted by a layered fashion. The experimental results show that palmprint identification based on feature extraction in the frequency domain is effective in terms of accuracy and efficiency.

scaffolds are made with spinning techniques either using polymer solutions or melts. [ 3,4 ] The primary focus of the spinning technique is the production of fi bers in a scale range from nano-to microrange that resembles the native extracellular matrix (ECM). [5][6][7] Although there has been much research on solution spinning to form fi brous polymer scaffolds for tissue engineering and wound healing applications, little has been reported on melt spinning to fabricate nonwoven scaffolds. [ 8,9 ] Melt spinning does not require solvents that are mostly cytotoxic, therefore it offers a distinct advantage. In addition, the surface topography of the fi brous scaffolds which can affect cellular infi ltration can be better controlled by melt spinning. [ 8,10 ] Poly(ε-caprolactone) (PCL) is one of the most promising linear aliphatic polyesters used extensively in the biomedical field since it is biodegradable in an aqueous medium and biocompatible in biological applications. This semi-crystalline polymer has a low melting point (60 °C) and a glass transition temperature (−60 °C) and therefore it could be fabricated easily into any shape and size. [11][12][13] The superior rheo logical properties and mechanical properties of PCL have A pressurized melt gyration process has been used for the fi rst time to generate poly(ε-caprolactone) (PCL) fi bers. Gyration speed, working pressure, and melt temperature are varied and these parameters infl uence the fi ber diameter and the temperature enabled changing the surface morphology of the fi bers. Two types of nonwoven PCL fi ber constructs are prepared. First, Ag-doped PCL is studied for antibacterial activity using Gram-negative Escherichia coli and Pseudo monas aeruginosa microorganisms. The melt temperature used to make these constructs signifi cantly infl uences antibacterial activity. Neat PCL nonwoven scaffolds are also prepared and their potential for application in muscular tissue engineering is studied with myoblast cells. Results show signifi cant cell attachment, growth, and proliferation of cells on the scaffolds.

In this work, the biosensing and antibacterial capabilities of PVA-lysozyme microbubbles have been explored. Gas-filled PVA-lysozyme microbubbles with and without gold nanoparticles in the diameter range of 10 to 250 μm were produced using a single-step pressurized gyration process. Fluorescence microscopy showed the integration of gold nanoparticles on the shell of the microbubbles. Microbubbles prepared with gold nanoparticles showed greater optical extinction values than those without gold nanoparticles, and these values increased with the concentration of the gold nanoparticles. Both types of microbubbles showed antibacterial activity against Gram-negative Escherichia coli (E. coli), with the bubbles containing the gold nanoparticles performing better than the former. The conjugation of the microbubbles with alkaline phosphatase allowed the detection of pesticide paraoxon in aqueous solution, and this demonstrates the biosensing capabilities of these microbubbles.

Daytime radiative cooling has attracted considerable attention recently due to its tremendous potential for passively exploiting the coldness of deep-sky as clean and renewable energy. Many advanced materials with novel photonic micro-nanostructures have already been developed to enable highly efficient daytime radiative coolers, among which the flexible hierarchical porous coatings (HPCs) are a more distinguished category. However, it is still hard to precisely control the size distribution of the randomized pores within the HPCs, usually resulting in a deficient solar reflection at the near-infrared optical regime under diverse fabrication conditions of the coatings.We report here a three-phase (i.e., air pore-phase, microsphere-phase and polymerphase) self-assembled hybrid porous composite coating which dramatically increases the average solar reflectance and yields a remarkable temperature drop of ~10℃ and ~30℃ compared to the ambient circumstance and black paint, respectively, according to the rooftop measurements. Mie theory and Monte Carlo simulations reveal the origin of the low reflectivity of as-prepared two-phase porous HPCs, and the optical cooling improvement of the three-phase porous composite coatings is attributed to the newly generated interfaces possessing the high scattering efficiency between the hierarchical pores and silica microspheres hybridized with appropriate mass fractions. As a result, the hybrid porous composite approach enhances the whole performance of the coatings, which provides a promising alternative to the flexible daytime radiative cooler.