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Microwave-assisted synthesis of 1,4-dihydropyridine derivatives
No full textPoslednjih nekoliko godina, posebnu pažnju privlače organske sinteze potpomognute
mikrotalasnim zračenjem. U ovom radu, poseban akcenat stavljen je na primenu mikrotalsnog
zračenja u postupku dobijanja N-heterocikličnih organskih jedinjenja. 1,4-Dihidropiridini poznati
kao blokatori kalcijumskih kanala, uveliko se primenjuju u tretmanu različitih kardiovaskularnih oboljenja.
Takođe, njihovi analozi, od kojih su najpoznatiji derivati akridina, imaju široku farmakološku
primenu. Inspirisano ovim činjenicama, polazeći od dimedona, odgovarajućih (hetero)aromatičnih
aldehida i amonijum-acetata, uz primenu mikrotalasnog zračenja, sintetisana je serija novih monosupstituisanih
derivata akridina. Uticaj hemijske strukture na farmakološki potencijal ovih
jedinjenja, procenjen je primenom različitih empirijskih pravila i in silico metoda. Rezultati ostvareni
u ovom radu, pružiće značajan uvid u sintetske protokole potpomognute mikrotalasnim zračenjem
koji će dati nova potencijano farmakološki aktivna organska jedinjenja.In recent years, the utilization of microwave energy resulted in the introduction of innovative
applications across various fields of chemistry. In this work, we highlight the use of microwave energy
as an effective method for designing a diverse range of N-containing bioactive compounds with
high yield and selectivity. 1,4-Dihydropyridines represent a well-known class of calcium antagonists
which are commercially employed for the treatment of cardiovascular disease. In addition, its analogues,
among which the most famous are acridine derivatives, have a wide range of pharmacological
applications. Motivated by these facts, starting from dimedone, the corresponding (hetero)aromatic aldehyde and ammonium-acetate, using microwave energy, we synthesized a series of monosubstituted
derivatives of acridine. The influence of the chemical structure on the pharmacological potential
of this compounds was evaluated using appropriate empirical methods and different in silico
methods. The results within this article will provide valuable insights into the microwave synthetic
protocols of heterocyclic compounds, which will be extensively studied for their potential application
in drug discovery
Exergy analysis and machine learning for enhanced eaf steel recycling
No full textThis study relies on exergy principles to analyze the sustainability of the steel re cycling process in electric arc furnaces. Focusing on a balance between material and energy efficiencies, the research addresses the degradation of elements such as manganese and silicon from steel to slag phase. Machine learning techniques were employed to predict and optimize element distribution coefficients. By lever aging HSC v.9 software, a detailed exergy analysis was performed, utilizing pre cise coefficients for element distribution in steel and slag, with energy consump tion. The results demonstrate the potential of integrating exergy analysis and ma chine learning to enhance the sustainability of steel production, aligning with cir cular economy principles
Eco-friendly functionalization of viscose with bioactive plant extracts
No full textGiven the increasing demand for multifunctional products with programmable and biological functionalities, this study aims to develop bioactive cellulose materials using a cost-effective, eco-friendly process. Plant extracts are well-suited for textile processing due to their accessibility, non-toxicity, biocompatibility, and eco-friendly nature. In this study, viscose fabrics were treated with aqueous solutions of plant extracts from five selected species: industrial hemp (Cannabis sativa L.), mountain germander (Teucrium montanum L.), herb-robert (Geranium robertianum L.), lady’s mantle (Alchemilla viridiflora Rothm.), and pomegranate (Punica granatum L.). Periodate oxidation and chitosan deposition were used to enhance fabric properties. The antimicrobial activity of viscose fabrics treated with plant extracts was assessed using the agar diffusion method on Gram-positive microorganisms: Staphylococcus aureus (clinical isolate and strain ATCC 25923), as well as Gram-negative microorganisms: Escherichia coli strain ATCC 25322 and a clinical isolate of Pseudomonas aeruginosa. All samples treated with plant extracts exhibited antimicrobial activity, evidenced by inhibition zones or contact activity against the tested microorganisms. Samples treated with pomegranate peel and hemp extracts exhibited the highest efficacy against Gram-positive bacteria (inhibition zone of 20 mm), while those treated with pomegranate peel extract showed the highest activity against Gram-negative bacteria (inhibition zone of 17.5 mm). The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl reagent; the results indicated significant antioxidant effects across all viscose fabrics functionalized with plant extracts. The highest antioxidant activity was recorded in samples treated with extracts of lady’s mantle at 80%, teucrium montanum at 76%, and pomegranate peel at 70%. Interactions between hemp and pomegranate extracts were further investigated using in silico methods to gain insights into the types of interactions and to identify key functional groups/atoms involved in complex formation between chitosan and extract constituents. Results indicate that the examined plant extracts could serve as suitable replacements for synthetic agents in textile functionalization
Optimized UHPLC-MS/MS method for the determination of quaternary ammonium compounds in water
No full textObjective
Quaternary ammonium compounds (QACs) are a class of cationic surfactants with potent
antimicrobial properties and widespread application in household and industrial disinfectants. Due
to their chemical stability and extensive use, QACs are increasingly detected in surface water and
wastewater, raising concerns over their potential adverse effects on aquatic ecosystems. This study
aimed to develop and validate a sensitive and selective analytical method for the quantification of
14 QACs in water samples using ultra-high performance liquid chromatography coupled with
tandem mass spectrometry (UHPLC-MS/MS)
Memory Effect of Double Oxides Compared to Simple Ion Exchange for Controlled Fluoride Ion Capture and Release
No full textA layered double hydroxide (LDH) containing Mg and Al was synthesized from a nitrate solution using a coprecipitation method. The resulting material exhibited a homogeneous structure, which, upon calcination at 450 °C, was converted into a layered double oxide (LDO). When rehydrated in a fluoride-containing aqueous solution, the original hydroxide structure was successfully regenerated, demonstrating the LDH’s memory effect. During this transformation, fluoride anions from the solution were incorporated into the interlayer galleries to maintain electroneutrality, as confirmed by energy-dispersive X-ray spectroscopy (EDS) analysis. Separately, the process was tested in the presence of ethanol, which significantly enhanced the incorporation of fluoride ions into the interlayer spaces. The material’s potential for controlled fluoride release was evaluated by monitoring its release into demineralized water. For comparison, a simple ion-exchange process was carried out using the as-synthesized MgAl LDH. The memory effect mechanism displayed a notably higher fluoride incorporation capacity compared to the ion-exchange process. Among all the specimens, the sample reconstructed in the presence of ethanol exhibited the highest fluoride ion content. Fluoride release studies revealed a two-phase pattern: an initial rapid release within the first three hours, followed by a substantially slower release over time
Hydrogen evolution reaction on electrodeposited Ni-MoOx composite coatings
No full textNi-MoOx composite coatings were electrodeposited under severe hydrodynamic conditions from the suspension containing NH4Cl, NiCl2 and MoOx powder. For the first time in the literature room temperature XRD analysis of as-prepared MoOx powder revealed the presence of different compounds: MoO2.8, H2MoO4, MoO3, MoO2 and (NH4)2Mo2O7. XPS analysis confirmed their presence in the coating: Mo6+ and Ni2+ species found on the top surface, and Mo4+, Mo5+, Mo6+, Ni2+, Ni0 species detected deeper within the coating. SEM-EDS analysis confirmed that coatings electrodeposited from higher concentrations of MoOx are rougher and contain higher amount of Mo. MoOx particles embedded in the composite coatings were found to be amorphous, only Ni was crystalline (as confirmed by SAED analysis). The HER was investigated in 30 wt. % KOH at 70 °C, with the lowest η at j = -500 mA cm-2 amounting to -88 mV for the best Ni-MoOx sample. A modified approach to the analysis of Nyquist plots recorded at different η values enabled determination of the exchange current densities for the charge transfer reaction (jo,ct), intermediate adsorption reaction (jo,ads) and total HER (jo,tot) from the dependences ηcorr vs. log(Rct-1), ηcorr vs. log(Rp-1), ηcorr vs. log(RF-1) and log τ vs. ηcorr. It should be emphasized that jo,tot is not a simple sum of jo,ct and jo,ads since both reactions occur simultaneously and are potential-dependent. The accelerated service life test (ASLT) confirmed the superior performance of the most active Ni-MoOx coating compared to the commercial De Nora cathode
Low-Cost and Eco-Friendly method for activating carbon felt using hypochlorite for electrochemical applications
No full textPristine carbon felt is activated and functionalized through a cost-effective, eco-friendly method by immersion in a commercial 5 wt% hypochlorite solution. Electrochemical analyses, including cyclic voltammetry, galvanostatic charge–discharge tests, capacitance, and impedance measurements at 1 Hz, reveal that the activated carbon felt exhibits a twenty-fold enhancement in performance compared to its pristine counterpart. Pristine and activated carbon felt are characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, contact angle measurement, and water uptake tests confirming the significant changes in material properties. To further validate the activation process, polypyrrole is galvanostatically electrodeposited on both pristine and activated carbon felts, with their electrochemical behaviors serving as a model system. The findings indicate a substantial improvement of activated carbon felt, with fourth times increase in capacity, highlighting the potential for advanced applications
Sustainable Lightweight Concrete Designed with Modified Solidified Wastewater Sludge as Partial Replacement of Cement
No full textThe requirement for high-quality drinking water and the treatment of wastewater prior to discharge into the environment results in the generation of sludge. As with any high-volume materials, beneficial reuse applications are being sought to promote sustainable environmental solutions. This research examined the possibilities of producing sustainable lightweight concrete using modified solidified wastewater sludge as a partial replacement of cement. Wastewater sludge was modified by the addition of aluminum oxide and magnesium silicate hydrate. The properties of the modified wastewater sludge were examined, as well as the influence of the partial cement replacement with the sludge in lightweight concrete. Besides testing the physical and mechanical properties of four mortar mixtures, an additional analysis of the willingness of final users to accept novel material containing wastewater sludge was addressed. The results obtained for the mortar samples indicate that 20% cement replacement is the upper limit for the modified sludge’s application. The lightweight concrete prepared with the modified sludge (in the amount of 20%) was tested in a hardened state. The water permeability was reduced by 33.3% with the addition of the modified sludge. Both tested concrete mixtures showed good frost resistance. The maximal measured reduction in the compressive strengths was 7.6%. Citizens’ perceptions and responses regarding the beneficial reuse of materials emphasize the importance of comprehensive education for their future acceptance
Nature-Derived corrosion inhibition of steel in HCl by Pančić spruce essential Oil: Insights from experimental and Computational Approaches
No full textThis study examines the potential of essential oil extracted from the needles of Pančić spruce as an innovative, eco-friendly corrosion inhibitor for carbon steel in a 1 M HCl solution. Analysis by GC/MS and FTIR revealed that the essential oil is rich in active organic compounds. Impedance measurements showed a significant increase in charge transfer resistance values for steel samples treated with the oil, achieving a maximum inhibition efficiency of 93 % at a concentration of 200 ppm after 4 h. Polarization measurements indicated that the oil acts as a mixed-type inhibitor. SEM demonstrated that the oil significantly altered the surface morphology of carbon steel. Adsorption studies followed the Langmuir isotherm, while thermodynamic analysis suggested that the organic components of the oil adsorb onto the metal surface through a combination of physisorption and chemisorption. XPS confirmed the presence of a protective film consisting of Fe oxides/hydroxides and phytochemicals from the essential oil. Theoretical methods (DFTB-MD) supported the experimental data, predicting strong interactions between key phytochemicals and the Fe surface. This study opens the door for further exploration of conifer essential oils as sustainable corrosion inhibitors, contributing to the global shift towards green chemistry and reducing the environmental footprint in industrial applications
Anti-neuroinflammatory potential of hydroxybenzoic ester derivatives: In silico insight and in vitro validation
No full textThis study explores the anti-neuroinflammatory and antioxidant potential of 42 hydroxybenzoic acid esters and three parent acids. Molecular docking simulations targeted key proteins involved in the lipopolysaccharide (LPS) signaling pathway to identify lead compounds for synthesis and in vitro evaluation. Among the screened esters, the most promising candidates demonstrated antioxidant activity comparable to vitamin C in ABTS and DPPH assays. Additionally, these esters significantly reduced the production of reactive oxygen species (ROS) and nitric oxide (NO) in H2O2- and LPS-stimulated BV2 microglial cells, indicating their ability to attenuate neuroinflammation. Further testing in SH-SY5Y neuronal cells exposed to microglia-derived supernatants confirmed the neuroprotective effects of these esters, reducing microglia-mediated neurotoxicity. These results suggest that hydroxybenzoic acid ester derivatives are promising candidates for mitigating microglia-driven neuroinflammation and protecting neurons, offering potential therapeutic applications for neurodegenerative diseases