Current Materials Science - Volume 15, Issue 2, 2022

Localized drug delivery to the respiratory system has become an increasingly successful and essential treatment strategy for several pulmonary diseases, including asthma, chronic abstractive disease, pneumonia, bronchitis, and cystic fibrosis. The rising incidence of respiratory diseases is a significant factor driving the worldwide market for respiratory inhaler devices. The objective of this article is to present various aspects of pharmaceutical aerosols, including their types, components, fundamentals, in-process and finished product quality control tests based on pharmacopeial standards and specifications, and commercial utility considering the pharmaceutical aerosol dosage forms that have been patented from 2000 to 2020, along with a list of marketed pharmaceutical products. Aerosol, collectively referred to as a pressurized device, operates by triggering an appropriate valve system with a continuous or metered dosage of tiny mist spray. It is used not only in the treatment of asthma and chronic obstructive pulmonary disease but also in the treatment of cancer, diabetes, migraine, angina pectoris, acute lung injury, bone disorders, tuberculosis, and many more. A multitude of different variables, including types and properties of propellants, active substances, containers, valves, actuators, spray patterns, valve crimping efficiency, and particle size of the aerosols, influence the therapeutic effectiveness of pharmaceutical aerosols. Based on the current findings, distinct characteristics such as the elimination of first-pass metabolism, quick drug absorption, ease of therapy termination, as well as a larger surface area have attributed to the success of pharmaceutical aerosols.

Background: Gentian violet dye released from industries into the environment has caused serious water pollution and is a significant environmental pollutant to human beings owing to the toxicity. It is urgent to decrease environmental pollution by removing gentian violet in the wastewater. Objective: The aim is to synthesize hexahydroxy strontium stannate/tin dioxide nanocomposites by a simple hydrothermal method without surfactants and research the photocatalytic performance for gentian violet degradation. Methods: Hexahydroxy strontium stannate/tin dioxide nanocomposites have been obtained via the hydrothermal method. The structure, size, morphology and photocatalytic performance were characterized by X-ray diffraction, electron microscopy, solid ultraviolet-visible diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. Results: The nanocomposites possess oven-shaped morphology with the size of less than 100 nm and are composed of hexagonal SrSn(OH)6 and tetragonal SnO2 phases. The band gap of the nanocomposites is 3.52 eV. 10 mg hexahydroxy strontium stannate/tin dioxide nanocomposites have the ability to completely degrade 10 mL gentian violet solution with the concentration of 10 mgL^-1 under 6 h ultraviolet-visible light irradiation. Hydroxyl radical, hole and superoxide radical are the main species for the gentian violet photocatalytic degradation using the nanocomposites. Conclusion: The hexahydroxy strontium stannate/tin dioxide nanocomposites show good photocatalytic performance for the GV degradation. The photocatalytic performance for gentian violet degradation using the hexahydroxy strontium stannate/tin dioxide nanocomposites depends on the irradiation time and content of the nanocomposites.

Background: High-density Fiberboards (HDF) are widely used as a substitute for solid wood in furniture, cabinet, construction materials, etc. Wood fibers are often used in the production of HDF but the use of renewable materials has gained worldwide interest brought about by global pressure to pursue sustainable development. An abundant source of renewable fibers that can be used to produce HDF is keratin from waste chicken feathers. The goal of the study is to investigate the use of keratin fibers in combination with wood fibers to produce HDF. No or limited studies have been conducted in this area and if successful, it could offer an alternative utilization for the billions of kilograms of waste feather produced by the poultry industry. HDF is a high volume feather utilization that can reduce pollution and help solve solid waste disposal problems in many countries. Methods: A series of dry-formed HDFs containing varying ratios of wood and keratin fibers bonded by polyurethane resin were produced. The physical and mechanical properties of the HDFs were determined. Results: The properties of the HDFs were affected by varying ratios of wood particles and keratin fibers. Dimensional stability as indicated by low levels of thickness swelling (<4.6%) and water absorption (<10%) was observed. Internal bond (2.47 MPa), MOE (5.8 GPa) and MOR (45 MPa) values were higher or comparable to those reported in the literature. Conclusion: HDF formed using a combination of wood and keratin fibers bonded together by polyurethane resin to as much as 50% keratin fibers were dimensionally stable with stiffness and strength above the minimum requirements for general use HDF as prescribed by EN 622-5.

Background: Cementitious composites, which are subject to increasing demands, are often exposed to various external attacks, such as aggressive groundwater and surface water, chemicals in the soil, gas penetration, or phenomena related to water freezing and melting. One of the most common reasons for the deterioration of cement composites is the corrosion process. Corrosion results in irreversible damage that occurs during the chemical reaction of the material with the components of the environment. Methods: The paper deals with experimental study of chemical sulphate corrosion of cement composites prepared from three types of cement: ordinary Portland cement; sulphate-resistant cement; and special hybrid cement, and industrial by-products and wastes: silica fume, zeolite and a special mineral admixture based on blast furnace granular slag as cement partial substitutes. Samples of cement composites were subjected to corrosion experiments in a sulphate environment, which took place in the laboratory under model conditions for 180 resp. 270 days. Results: The deterioration parameters: changes in the weight and thickness of the samples, surface and mineralogical changes, leachability of the basic components of the cement matrix as well as changes in the liquid phase proved the degradation process due to chemical sulphate corrosion, model solutions of H2SO4 with pH 3 and 4, and solution of MgSO4 with c (SO4^{2 -}) = 3 and 10 g /L. Conclusion: By comparing the leachability of the alkali components from cement composites, it can be concluded that for the most aggressive model solution (H2SO4 with pH 3), both slagcontaining formulations are the most stable in terms of the total ratio of leached calcium and silicon. This finding is also supported by the results of water absorbency tests, which confirmed that despite the increase in absorbency after chemical corrosion, cement composites with slag content reach the lowest values.

Background: Green synthesis of nanoparticles has provided a cost-effective, environmentally friendly method, as well as raised safe strategies for the synthesis of nanomaterials. Methods: In this study, we investigated the synthesis of Selenium nanoparticles from the leaf aqueous extract of Moringa oleifera (MO-SeNPs) and studied the effect of MO-SeNPs and Moringa extract with various concentrations on the growth, active constituents, and antioxidant activity (scavenging DPPH) of Populus alba callus. MS medium supplemented with (2, 4-D at 2 mg/l + 0.5 mg/l BA) took the maximum callus induction percentage (100%), increasing the callus fresh weight, dry weight, and degree of callus formation compared with (2.0 mg/l 2,4-D + 0.5 mg/l Kin). Results: The highest values of callus fresh and dry weight were recorded on MS containing 20% MO-SeNPs. Regarding the active constituents, the GC-MS chromatogram revealed the presence of 23 major compounds identified in the chloroform extract. The phytoconstituents with maximum peak area in callus extract are Tetradecane, Hexadecen-1-ol, Trans-9, 5-Octadecene, (Benzene, 1- pentyloctyl), (Benzene, 1-butylnonyl), Cycloeicosane, and 10-Heneicosene in all treatments. Moringa extract and MO-SeNPs stimulate the increase of compounds in callus compared to control. In this regard, MO-SeNPs 5% led to a higher increase in the area percent of active substances compared to the treatment of Moringa extract and control. Concerning the antioxidant activity, the results indicated that Moringa extract and MO-SeNPs had a positive effect on scavenging DPPH compared with the control. The highest percentages of scavenging DPPH were recorded when Populus alba L. callus treated with MO-SeNPs 20%, 10%, and Moringa extract 20%, percentages reached (84.65, 75.35, and 71.94%), respectively. Conclusion: Green synthesis of MO-SeNPs improved secondary metabolites and antioxidant activity in Populus alba L. callus.

Background: Formaldehyde is a chemical used in several textile production processes, such as hardening of fibers and antimold finishing. However, it has varying effects on humans, such as irritation of the eyes, nose, throat, wheezing, chest pains and bronchitis. In the midst of COVID-19, individuals are using various fabrics for face mask production, which may be containing levels of formaldehyde that can negatively affect their health. Methods: This study investigated formaldehyde levels in fabrics on the Ghanaian market to determine compliance to standards set by the Ghana Standards Authority (GSA) with the aid of experimental procedures. Thirty-two (32) different brands of fabrics were selected for the investigation. Formaldehyde levels were determined using a spectrophotometer (DR6000). Data were analyzed using the Statistical Product and Service Solutions (SPSS) for Windows version 22. The mean performance attributes and the formaldehyde levels of the sampled fabrics were determined before and after washing. Inferential statistics (Analysis of Variance and Paired Samples t-test) at 0.05 alpha levels were used to determine significant differences between and among the groups involved. Results: The fabric samples tested positive for formaldehyde before and after washing, with some exceeding the standard limits set by the GSA before washing. Significant differences existed between and among the samples with regard to formaldehyde levels as well as weight and weave types of the samples and formaldehyde levels. Conclusion: Washing significantly reduced the formaldehyde levels in the fabrics. It is recommended that Ghana Standards Authority takes a further look at the fabrics on the Ghanaian market to ensure manufacturers comply with set standards and consumers are also advised to wash their clothes at least once before use to reduce the level of impact formaldehyde resin may have on them.