Cotton gauze (CG) is the most commonly used primary wound dressing to protect wounds from the external environment. However, it is highly susceptible to fouling due to the adhesion of bacteria present on the wound surface. Bacterial colonization of the dressing is detrimental as it aids in wound infection and delays wound healing. To mitigate this issue, the objective of this study was to transform the inert CG into a fouling-resistant wound dressing that can actively resist bacterial adhesion and also prevent biofilm formation on the surface of cotton. In this work, a facile method of modifying commercial CG using oxidized dextran (Odex) was developed. Odex was derived from dextran via periodate oxidation reaction and then coated over the CG using mussel-inspired chemistry. The resultant Odex-modified CG demonstrated a substantial reduction in bacterial adhesion after 4 h of incubation in bacterial suspension. The modified gauze suppressed biofilm formation, achieving ~83% reduction in viable bacterial count as compared to unmodified CG after 48 h of incubation in the bacterial suspension. In addition, the modified CG also showed good breathability, wettability and moisture retention properties. The results suggest a promising approach of transforming inert CG into a potential fouling-resistant wound dressing for the management of wound infections.
The enhancement of light absorption and surface area in monocrystalline solar cells is achieved through anisotropic etching, with the aim of improving its conversion efficiency. Nevertheless, the conventional method of anisotropic etching is constrained in its capacity for incrementing surface area. Herein, a promising texturization process in the form of a homogenous and uniform pyramidal structure is proposed with two-step texturing processes: cyclic voltammetry (CV) treatment and the alkali anisotropic etching method on the silicon wafer surface. Prior to and following the alkali texturing process, the silicon surface was modified using the CV treatment. The effect of this approach was investigated under different CV cycles (20, 40, 60 and 80 cycles) in a 0.5 M Na2SO4 aqueous electrolyte with pH ~ 7. Based on the field emission scanning electron microscope (FESEM) micrographs and UV-visible spectrometer (UV-Vis) measurements, the wafer textured with 60 cycles of CV treatment and an alkali anisotropic etching process tremendously improves the surface morphology and decreases the front surface reflection. As a result, the size and height of the pyramid formed were 2.1–2.3 µm and 0.6–1.9 µm, respectively. Moreover, the outlined methodology facilitates a substantial decrease in surface damage and is applicable in the Si texturization process for the manufacturing of solar cells.
Nowadays, extreme environmental conditions are one of the main factors causing the deterioration of monuments built with limestone. Therefore, this study proposed the evaluation of the consolidating effect of calcium zinc hydroxide dihydrate nanoparticles, with the molecular formula CaZn2(OH)6·2H2O (CZ), applied on Calcehtok limestone. The consolidating effect of nanoparticles was characterized through mineralogical analysis by X-ray diffraction (XRD), and the morphological and elemental composition by scanning electron microscopy (SEM) on 2.2 cm × 1 cm × 1.5 cm limestone samples. The petrophysical properties as spectrophotometry, Leeb hardness test and contact angle, were measured on 5 cm × 5 cm × 3.5 cm limestone samples. In addition, XRD studies were carried out on the CZ-treated and -untreated stones under laboratory conditions and exposed to the natural environment. The results obtained through an accelerated chamber of relative humidity (RH, 80%) and temperature (25 °C) showed an improvement in Leeb hardness and contact angle, without affecting the color of the stone. Therefore, it is proposed that the warm conditions of relative humidity and temperature favor the consolidation, as the pores are filled by the binding of calcite grains as seen by SEM. After 15 days of exposure, a rapid transformation of portlandite into calcite was observed, while at 30 days, calcite and zincite can still be detected by XRD. The combination of SEM and XRD techniques, together with the measurement of petrophysical properties, corroborated these results, showing the homogenization of the surfaces of the samples due to the decrease of cracks, the filling of cavities, and pores; therefore, this treatment favored its resistance. The XRD results further confirmed the presence of CZ after 30 days under the both laboratory and natural conditions, and its degradation into calcite and zincite was still ongoing after 90 days of exposure.