The development of sustainable and environmentally friendly defoliants has become a critical area of research due to the increasing demand for eco-conscious agricultural practices. Traditional chemical defoliants used in cotton harvesting have raised concerns over their environmental toxicity and adverse health effects. In this context, the calcium chlorate–monochloroacetic acid–triethanolamine–water system has emerged as a promising alternative, offering a less toxic and biodegradable solution. However, the solubility and crystallization behavior of this system, particularly under varying temperature conditions, remain poorly understood, limiting its large-scale application in the field. This study investigates the solubility diagrams and crystallization phases of the calcium chlorate–monochloroacetic acid–triethanolamine–water system across temperatures ranging from -52°C to 47°C. The goal is to optimize the defoliant formulation by identifying key phase boundaries and new crystalline phases. The study identified several crystalline phases, including Ca(ClO₃)₂·6H₂O, Ca(ClO₃)₂·4H₂O, and Ca(ClO₃)₂·2H₂O, as well as a novel compound, ClCH₂COOH·Ca(ClO₃)₂·(C₂H₄OH)₃N, which was confirmed through infrared spectroscopy (IR) and scanning electron microscopy (SEM) analysis. These findings provide valuable insights into the phase behavior of this system, potentially leading to the production of more efficient and sustainable defoliants for the cotton industry. Future research should focus on scaling up these results for field applications and exploring additional environmentally friendly compounds to further enhance agricultural sustainability.

Thiosemicarbazones are recognized for their flexibility in coordination and various applications in areas such as medicinal chemistry, catalysis, and material science. Thiosemicarbazone metal complexes are a significant area of study due to their intriguing properties and applications across multiple scientific fields. By using density functional theory (DFT) and molecular docking methods, researchers conduct computational studies to elucidate the structural, electronic, and reactivity characteristics of these complexes. These investigations not only aid in understanding experimental data but also guide synthetic strategies by offering predictive insights into the structural features of the complexes. Additionally, these computational approaches allow scientists to analyze electronic structures and spectroscopic properties, which is essential for elucidating reactivity patterns and establishing structure–activity relationships (SARs). In biological contexts, these studies provide insights into how these complexes interact with biological targets, enhancing our understanding of their mechanisms of action and informing the design of therapeutic agents that exhibit improved efficacy and decreased toxicity. Computational studies bridge the gap between experimental research and theoretical understanding, enabling scientists to predict and optimize the behavior of metal complexes in various chemical and biological systems. In this study, we discuss the computational insights of thiosemicarbazone metal complexes, exploring their structural properties, reactivity, and biomedical applications.

Gold nanoparticles are promising candidates as vehicles for drug delivery systems and could be developed into effective anticancer treatments. Gold nanorods (GNRs) have suitable optical and thermal properties, which allows them to be used in techniques such as photothermal therapy and photoacoustic imaging.

GNRs with an absorbance peak near 650 nm were synthesized via a seed-mediated method and coated with cross-linked BSA as a stabilizer. New cancer treatment approaches involve the use of several cytostatics to target cancer cells. Therefore, in our work a mixture of cytostatics doxorubicin and dacarbazine were loaded onto the GNRs. Тhe effectiveness of drug loading was determined using UV spectroscopy. TEM and dynamic light scattering were used to verify the structural integrity of the BSA-coated GNRs.

Cytocompatibility of bare and BSA-coated gold nanorods with different ratios of doxorubicin and dacarbazine was assessed by MTT assay, a common method to evaluate the biocompatibility of nanomaterials. 3D tumor spheroids were used to assess the drug gradient uptake and the effect of localized photothermia mediated by GNRs coated with cross-linked BSA alone or in combination with doxorubicin. Тhe results of experiments using GNRs and doxorubicin on irradiated cells and on cells that were not irradiated showed significant differences.

The work was carried out with the financial support of the Ministry of Health of the Russian Federation ‘Molecular design and creation of drugs based on conjugates of carbon nanostructures, vectors of targeted delivery and cytotoxic agents for inactivation of stem tumour cells and components of the tumour microenvironment’, No. EGISU:1022040700957-7-3.2.21;3.1.3.

Research was performed using the equipment of the Resource Centre ‘GeoModel’, Interdisciplinary Resource Centre for Nanotechnology and Centre for Chemical Analysis and Materials Research of the Research Park of Saint Petersburg State University

Bismuth and its compounds are generally recognized for their biological safety and non-toxicity, making them highly valuable for large-scale synthesis of various bismuth-based complexes for their use in diverse biological applications. Bismuth complexes have shown promising antiviral, antifungal, antibacterial, antileishmanial, and anticancer properties. Notably, bismuth drugs are among the few antimicrobial agents that have not developed drug resistance and have a synergistic effect with antibiotics. Studies have explored that the biological activity of bismuth-containing compounds is closely related to the type of ligand and the geometry of the complex, emphasizing the importance of these factors in drug development. The biological activities of the resulting bismuth complexes are often influenced by the properties and positions of the substituted groups on ligand, indicating that even slight modifications can have profound effects on their efficacy. Computational studies provide a detailed insight for understanding the structure, stability, and reactivity of compounds, which can be difficult to achieve only through experimental methods. By utilizing computational methods like DFT and molecular docking, we can predict how ligands will interact with different drug targets. This approach makes it easier to design and develop more effective compounds for various applications. In this study, we present several factors that can influence the optimization of geometry, vibrational frequencies, HOMO and LUMO energies, quantum chemical parameters, as well as biological activities for the ligand and its bismuth complexes.

Phosphate material have a wide range of applications in biological, and catalysis. It also showed fluorescence capacity, where lanthanide orthophosphate demonstarted a fluorescent properties during their internalization into human umbilical vein endothelial cell. In addition, it has been considered as ceramic materials with high magnetic and electrochemical properties [1].

Since the calcium phosphate nanoparticles utilization in biological, therapeutic, and bio-medicinal fields such as treatment of cancers, caries inhibition, researchers decrease; the researches increase the studies using other metals including phosphate materials. For example cobalt phosphate nanoparticles, which were modified by Nickel, and Zirconium and used as electro-catalyst for water treatment, dyes removal and treatment of cancers [2]. Considerable methods were used to synthesize phosphate material, such as precipitation, co-precipitation, impregnation, deposition, and hydrothermal rout. This later can be lead to different shape and structure.

In this study, we prepared iron copper phosphate nanoparticles (FeCuP) using hydrothermal rout. During preparation, several conditions were used modifying the urea amount. So, different structures were achieved. The material was characterized by SEM, EDX, UV-Vis and XRD. The material was used as catalyst for the synthesis of propargylamines and pyrroles. The nanoparticles catalyst was reused with high activity and stability.

References

[1] M. Moustafa, M. Sanad and M. Hassaan, Journal of Alloys and Compounds, 845 (2020) 156338.

[2] S.S. Sankar, A. Rathishkumar, K. Geetha and S. Kundu, Energy & Fuels, 34 (2020) 12891.

The electrochemical synthesis of ortho- and para-hydroxybenzoic acids (HBAs) using CO₂ presents a sustainable alternative to traditional methods. These acids, essential intermediates in the production of pharmaceuticals such as aspirin and in polymer manufacturing, are typically synthesized through energy-intensive processes. Given increasing concerns over carbon emissions, optimizing electrochemical approaches that incorporate CO₂ as a reactant is vital for improving both economic and environmental sustainability. This study focuses on optimizing the electrochemical synthesis of ortho- and para-HBAs in CO₂-saturated environments, aiming to enhance reaction efficiency, and selectivity, and reduce energy consumption. Cyclic voltammetry and constant potential electrolysis were employed, with various electrode materials tested to improve process efficiency. Results indicate that electrode material significantly influences both product selectivity and reaction efficiency. Platinum electrodes exhibited a 15% higher current efficiency and favored para-hydroxybenzoic acid, while carbon-based electrodes showed a 20% increased selectivity for ortho-hydroxybenzoic acid. Additionally, CO₂ improved the electrochemical environment by stabilizing radical intermediates and reducing overpotential by 30%. These findings suggest that utilizing CO₂ as a reactant not only enhances the sustainability of the process but also improves overall performance. In conclusion, this work offers a promising route for the electrochemical synthesis of hydroxybenzoic acids with reduced environmental impact. Further studies should focus on scaling the process and optimizing electrode materials to facilitate industrial applications, contributing to a greener chemical industry.

Creating inexpensive sensors that are easy to use is the goal of many authors and researches. Materials for implementation in similar types of devices as a sensitive medium are increasingly in demand. This medium in optical sensors needs to fulfill certain specifications: it needs to be compatible with various substrates, have an appropriate refractive index, be alterable in thickness, etc.

In the present study, the influence of deformations of a flexible substrate on an active amphiphilic PVA-Ac copolymer with a 24%-acetal-content sensing layer in a thin-film humidity sensor was studied. To improve the optical contrast, metallization of the PET substrate was used, which also aimed to increase the sensitivity. After a series of up to 1000 bends, certain characteristics of the sensor were studied: hysteresis, sensitivity, the change in the transmission coefficient, etc. The initial active layer was deposited using the spin-coating method, which is fast and easy and ensures the repeatability of the results. By using 3D profilometry, the quality of PVA-based active media thin films containing additional acetal groups was observed. It was demonstrated that the deformations had no negative effects on the sensor thin-film systems and, in fact, increased their sensitivity by more than 40%. We then present a discussion of the potential causes for this, including a decrease in the adhesion between the transparent metallized substrate and the sensing medium.

This study investigates the synthesis of herbicides based on p-chlorophenol (Cl-C₆H₄OH) and focuses on the polythermal solubility behavior of the NaOH – Cl-C₆H₄OH – H2O system. Understanding the solubility and phase transitions within this system is essential for optimizing the synthesis of herbicides. Solubility measurements were performed over a temperature range of -54.3°C to 59.0°C. A polythermal solubility diagram was constructed, identifying crystallization fields of ice, NaOH, NaOH•3.5H₂O, NaOH•5H₂O, NaOH•7H₂O, Cl-C₆H₄OH, and Cl-C₆H₄ONa. The compound Cl-C6H4ONa was isolated from its predicted crystallization region and identified using chemical and physico-chemical analysis, including infrared (IR) spectroscopy and scanning electron microscopy (SEM). The solubility diagram revealed distinct crystallization fields for various hydrates of NaOH and p-chlorophenol derivatives. Despite the high solubility of the initial components, the system exhibited a slight salting-out effect on the Cl-C6H4OH compound. The structure of the isolated Cl-C₆H₄ONa was further characterized using IR and SEM analyses, confirming its composition and morphology. The study provides valuable insights into the polythermal solubility of the NaOH – Cl-C₆H₄OH – H₂O system and the conditions necessary for the efficient synthesis of herbicides. The identification of specific crystallization fields and the detailed analysis of the isolated compound enhance the understanding of the phase behavior, contributing to more effective herbicide production processes.

ABSTRACT

In this study, poly-lactic acid (PLA)/ waste High-Density polyethylene (wHDPE) blend filled plantain peel particulates composites were fabricated using compression molding techniques with filler loadings ranging from 5 % to 50 % for treated and untreated fillers (Plantain peels particulates). The mechanical and morphological properties of the prepared composites were analysed and evaluated using scanning electron microscopy (SEM) to examine the tensile fracture surfaces. The results showed that tensile strength, impact strength and flexural strength decreased with increase in filler content. The highest values were recorded for 100 % PLA, tensile strength of 40.66 MPa, impact strength of 1.5 J/m², and flexural strength of 55.60 MPa, than its counterpart of 100 % wHDPE composites which shows tensile strength of 24.90 Mpa, impact strength of 1.0 J/m² and flexural strength of 31.98 Mpa. Lowest value of impact strength was seen at 50 % filler loading with 0.32 J/ m² and lowest hardness value 100 % wHDPE with 24 HV. The tensile modulus reached 3.307 GPa for 100 % PLA, while flexural modulus at 28,271.76 MPa, and hardness reached 54.61 Hv at 50 % filler content. SEM revealed better filler dispersion at 5 % filler loading compared to 50 %, where agglomeration occurred. The incorporation of plantain peels particulates can effectively be used as reinforcement / filler in PLA / wHDPE blends for applications like particle boards, shelve, partition wall and tabletops among others.

This work investigates the dynamic mechanical properties of low-density polyethylene (LDPE) and natural rubber (NR) composites reinforced with coir fibre, stressing the impact of dynamic vulcanisation on stiffness, energy dissipation, and damping behaviour. Prioritising sustainability, the composites were fabricated using a two-roll mill and compression moulding, incorporating 10% and 40% fibre loadings. Dynamic Mechanical Analysis (DMA) was used to determine the storage modulus (E’), loss modulus (E’’), and damping factor (tan δ) over a temperature ranging from 30°C to 120°C and a constant frequency of 10Hz. The findings revealed that dynamic vulcanisation considerably enhanced storage modulus across all temperatures, with a 25% increase in stiffness at lower temperatures. However, as the temperature increased, the modulus decreased due to polymer chain relaxation. Coir fibre composites also had higher loss modulus values, indicating more energy dissipation, but the damping factor increased with fibre content, showing weaker fibre-matrix interactions at higher loadings. While coir fibre composites demonstrated promising mechanical and thermal properties, they were exceeded by jute, hemp, and flax fibre-reinforced composites in terms of stiffness and energy retention. These findings emphasise the potential for dynamically vulcanised coir fibre composites to be employed in applications that require improved mechanical properties and thermal stability, establishing them as a sustainable option in specific engineering contexts.