A new denoising method for removing salt & pepper noise from image

Multimedia Tools and Applications - Digital image has a significant importance in many fields in human life such as, in medicine, photography, biology, astronomy, industry and defense. Thus, it...     

Uniform hollow-structured poly(vinyl amine) hydrogel microparticles with controlled mesh property and enhanced cell adhesion

This study introduces a useful approach for fabrication of hollow-structured hydrogel microparticles and for encapsulation of biomacromolecules in the hollow core of the particles. Monodisperse hollow-structured poly(vinyl amine) hydrogel particles were fabricated without using templates that combines the dispersion polymerization and the sequential hydrolysis/crosslinking. The hydrogel shell showed pH-dependent mesh sizes; ∼2 nm at a normal condition (pH 3–12) and ∼11 nm at an expanded condition (pH 2). By taking advantage of pH-responsive mesh property, we demonstrated that dextran macromolecules, whose hydrodynamic radius is between the mesh sizes of the normal and expanded pH conditions, could be encapsulated and stored inside of the shell. Moreover, our hydrogel particles showed strong adhesion to human cells. Some of them were even engulfed by the cell membrane and drawn into the cell even with no aid of site-specific moieties. From these results, it is expected that the hydrogel hollow microcapsules synthesized in this study could be used for delivery of macromolecules into the cells.     

Tropical algebra based adaptive filter for noise removal in digital image

Multimedia Tools and Applications - The concept of the tropical algebra was first introduced to solve problems in mathematical economy such as optimization and approximation problems. In this...     

Antioxidant Effects of the Ethanol Extract from Flower of Camellia japonica via Scavenging of Reactive Oxygen Species and Induction of Antioxidant Enzymes

The aim of this study was to investigate the antioxidant properties of the ethanol extract of the flower of Camellia japonica (Camellia extract). Camellia extract exhibited 1,1-diphenyl-2-picrylhydrazyl radical and intracellular reactive oxygen species (ROS) scavenging activity in human HaCaT keratinocytes. In addition, Camellia extract scavenged superoxide anion generated by xanthine/xanthine oxidase and hydroxyl radical generated by the Fenton reaction (FeSO(4) + H(2)O(2)) in a cell-free system, which was detected by electron spin resonance spectrometry. Furthermore, Camellia extract increased the protein expressions and activity of cellular antioxidant enzymes, such as superoxide dismutase, catalase and glutathione peroxidase. These results suggest that Camellia extract exhibits antioxidant properties by scavenging ROS and enhancing antioxidant enzymes. Camellia extract contained quercetin, quercetin-3-O-glucoside, quercitrin and kaempferol, which are antioxidant compounds.     

Effects of nonionic surfactant on the rheological property of associative polymers in complex formulations

The rheological properties of hydrophobically modified ethoxylated urethane (HEUR) were investigated in the presence of a nonionic surfactant, polyoxyethylene stearyl ether (C₁₈(EO)₂₀). The presence of nonionic surfactants played an important role in tuning the rheological properties of HEUR aqueous solutions. Observing both plateau modulus and viscoelastic relaxation time of HEUR aqueous solutions with varying the concentration of C₁₈(EO)₂₀ allowed us to demonstrate that C₁₈(EO)₂₀ readily interacts with the hydrophobic segments of HEUR polymers, which eventually formed a strong micellar network. Moreover, the micellar network formed at a critical concentration of C₁₈(EO)₂₀, ∼0.6% w/v, was indeed stable against both ionic strength and pH in the aqueous medium and complex formulations, such as a colloid suspension and an oil-in-water emulsion, thus providing more practical applications as thickeners for a wide variety of complex formulations.     

Role of pH-sensitive polymer–liposome complex in enhancing cellular uptake of biologically active drugs

In this study, we demonstrate the role of a pH-sensitive polymer–liposome complex in enhancing the delivery and the efficiency of bioactive drugs into cells. For this purpose, we made vesicles composed of poly(methacrylic acid-co-stearyl methacrylate), phosphatidylcholine, and cholesterol. The complex is stable at pH values above 6, but the structure becomes slightly disorganized at pH 5. Below pH 5, the complex readily precipitates. We made drugs-containing (calcein or α-ketoglutaric acid) vesicle dispersions and examined its cellular uptake and biological activity in vitro. Our results indicated that the polymer–liposome complex effectively enhances calcein delivery into human keratinocytes compared to liposome, but both vesicles showed an equal distribution of calcein inside melanocytes. Also, treatment of human dermal fibroblasts by using αKG-containing polymer–liposome complex dispersion significantly enhanced their production of procollagen compared to cells treated with αKG-containing liposome dispersion. The results are discussed by connecting the pH-dependent structural change of this carrier with the acidic environment of endosomes in the cells. Overall, the pH-sensitive polymer–liposome complex prepared in this study appears to be promising for the cytoplasmic delivery of bioactive agents.     

Boosting Sensitivity and Reliability in Field-Effect Transistor-Based Biosensors with Nanoporous MoS2 Encapsulated by Non-Planar Al2O3 (Adv. Funct. Mater. 42/2023)

Field-effect transistors-based biosensors (bio-FETs) have been considered an important technology for label-free and ultrasensitive point-of-care diagnostics. However, practical applications using bio-FETs are limited due to the trade-off between sensing reliability and sensitivity. This study suggests a reliable and sensitive bio-FETs based on nanoporous molybdenum disulfide (MoS₂) channels encapsulated by a non-planar high-k aluminum oxide (Al₂O₃) dielectric layer. Nanoporous MoS₂ thin film is fabricated with an abundant edge area and periodically ordered nanopores via block copolymer lithography. The ultra-thin Al₂O₃ dielectric layer deposited along the nanoporous structure of the MoS₂ realizes effective electrostatic control of charged biomolecules over the MoS₂ channel. In addition, it plays important roles in not only enhancing the electrical performance of the nanoporous MoS₂ bio-FETs, that is, mobility, hysteresis, and subthreshold swing, but also achieving effective biomolecular immobilization on the device surface. The nanoporous MoS₂ channel structure surrounded by non-planar Al₂O₃ detects a prostate cancer biomarker with an ultra-low limit of detection of 1 fg mL⁻¹. Moreover, the excellent selectivity, high sensitivity, and clinical reliability of the nanoporous MoS₂ bio-FETs are also confirmed. The proposed device platform provides new insights and technical advances in the field of FETs based sensors for future point-of-care devices.