The paper presents the process of cellulose extraction from rice straw using water–alkaline solution treatment and the subsequent process of carboxymethylation of the obtained product when activated by microwave radiation. After mercerization of rice straw, the obtained product contained 89.2% cellulose and 6.7% lignin. The X-ray diffraction pattern of the obtained lignocellulose shows three diffraction peaks in the region typical for the polymorphic modification of cellulose Iβ (2θ = 15.50(78), 21.70(145), 34.70(52)). The degree of crystallinity was 65%. The product was heat-stable up to 247 °C. The synthesis of carboxymethylcellulose (CMC) based on the obtained product included successive processes of thermostating in alcohol–alkali solution and cellulose esterification reaction using monochloroacetic acid. To activate the carboxymethylation process, microwave radiation was used (350 W for 90 s), which made it possible to reduce the reaction time by more than 100 times. Functional group analysis of the carboxylated lignocellulose from rice straw was carried out using an FTIR spectrometer. In the IR spectra, a band with a maximum of 1742 cm−1 was recorded, corresponding to stretching vibrations of >C(O)OH groups. The degree of polymerization was recorded by mass spectrometry.
Skin disorders are common and often chronic conditions with significant therapeutic challenges. Limitations of conventional treatments, such as adverse effects and antimicrobial resistance, have increased interest in plant-based alternatives. This article presents the phytochemical composition and pharmacological potential of several medicinal plants traditionally used in the treatment of skin diseases, including Rubus vulgaris, Plantago major, Artemisia terrae-albae, and Eryngium planum. Based on an analysis of scientific literature, the presence of bioactive compounds—including flavonoids, anthocyanins, phenolic acids, tannins, and sesquiterpenes—is summarized, along with their antioxidant, anti-inflammatory, and antimicrobial effects. Emphasis is placed on the correlation between traditional ethnomedicinal applications and pharmacological mechanisms. The findings support the potential of these species as sources for dermatological phytotherapeutics. Further research is needed to standardize active constituents, assess safety, and conduct clinical validation.
This study explores the transformative impact of three-dimensional printing, or additive manufacturing, in the development of bamboo-based 3D printing parts. Recently, there has been growing interest in incorporating natural fibers, such as bamboo, into polymers to enhance the structural integrity and strength of 3D-printed polymeric materials. This paper thoroughly examines the opportunities and obstacles associated with using additive manufacturing techniques to print bamboo fiber composites. This study includes an analysis of the mechanical properties, thermal properties, biodegradability, and environmental benefits of bamboo fiber composites. It also covers the processing methods and the printing parameters of bamboo fiber composites. This paper review focuses on the future prospects of bamboo fiber composites as a sustainable material in additive manufacturing based on the analysis of the existing literature and the recent research developments.
Monoamine oxidase (MAO) plays a key role in the pathogenesis of central nervous system disorders, and MAO inhibitors have been used in the treatment of depression and Parkinson’s disease. In the search for new classes of MAO inhibitors, the present study investigated a series of 1,2,4-oxadiazin-5(6H)-one derivatives. This study provides the first optimization of the reaction conditions for the condensation of amidoximes with alkyl 2-halocarboxylates to yield the desired 1,2,4-oxadiazin-5(6H)-ones. The results of the in vitro MAO inhibition studies showed that the 1,2,4-oxadiazin-5(6H)-ones were indeed inhibitors of human MAO with the most potent inhibition observed for 5f (IC50 = 0.900 µM) and 7c (IC50 = 0.371 µM). It was concluded that, with appropriate substitution, 1,2,4-oxadiazin-5(6H)-one derivatives would act as good potency MAO-B inhibitors and lead compounds for the development of antiparkinsonian drugs. In Parkinson’s disease, MAO-B inhibitors enhance central dopamine levels and reduce MAO-mediated production of hydrogen peroxide and resultant oxidative injury. This study represents one of few works to investigate synthetic approaches and biological activities of the 1,2,4-oxadiazin-5(6H)-one class of heterocycles.
The article studies the influence of chlorosulfonated polyethylene CSM 40 as a compatibilizer on the curing characteristics of the rubber compound, dynamic mechanical analysis, morphology, physico-mechanical and performance properties of vulcanized rubber based on a compound of ethylene propylene diene monomer EPDM S 501A and nitrile butadiene NBR 2645 rubbers. DMA studies indicate that the temperature dependence of tanδ for vulcanizates with and without a compatibilizer based on EPDM S 501A/NBR 2645 at a ratio of 75/25 parts per hundred parts of rubber (phr) has a bimodal character, which indicates the incompatibility of the rubber phases. The temperature dependence for EPDM S 501A/NBR 2645 vulcanizates (25/75 phr) with and without a compatibilizer has a monomodal form, which characterizes the improved compatibility of the rubber phases. SEM showed that a clearly defined microporous structure is observed on a cleavage of vulcanizate sample EPDM/NBR (25/75 phr) without a compatibilizer; with the addition of CSM 40, this feature is retained, but becomes less pronounced. It is shown that vulcanizates containing the compatibilizer CSM 40 are characterized by increased strength properties and hardness compared to vulcanized rubber without a compatibilizer. It was established that the vulcanized rubber based on EPDM S 501A/NBR 2645/CSM 40 (25/75/5 phr) is characterized by the smallest changes in the elastic-strength properties and hardness of vulcanizates after a day of thermo-oxidative aging in air and their weight after exposure to industrial oil I-20A and standard petroleum fluid SZhR-1 at room temperature among vulcanizates based on EPDM S 501A and NBR 2645. The vulcanizate of the rubber compound, including a compound of EPDM/NBR (25/75 phr) with a compatibilizer CSM 40 in an amount of 5 phr (2.88 wt.%), is characterized by stable physico-mechanical properties and improved performance properties. This rubber compound can be used for the manufacture of rubber products operating under the influence of oils and hydrocarbon environments.
30 November 2024 in South African Journal of Education
The purpose with this mixed-methods research was to examine students’ success in using artificial intelligence. The research sample consisted of 50 first-grade primary school students, 239 parents, and 25 primary school teachers studying in Almaty, Kazakhstan. A descriptive analysis technique was used to analyse the qualitative data. Findings are explained in themes. As a result of the research, it has been observed that parents’ attitudes towards their children’s use of technology were high. Most primary school teachers who participated in the research stated that students were interested in artificial intelligence, they supported the use of artificial intelligence technologies to some extent, and they found the students partially successful in this regard. Students participating in the research defined artificial intelligence as technology, computers that think like humans, smart machines, entertaining and educational computer content, robots that obey given commands, and technological devices that make life easier. Most students stated that they liked using artificial intelligence and that they found themselves somewhat successful in using artificial intelligence.