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In this study, sixteen secondary metabolites, including two chromones, four dibenzofurans, three lipids, three depsides, two aromatic compounds, a quinone, and a terpene, were detected in the methanol:acetone (1:1 v/v) extract of the lichen Hypotrachyna enderythraea (Zahlbr.) Hale, using High-Performance Liquid Chromatography coupled to Orbitrap Electrospray Ionization tandem Mass Spectrometry (HPLC-Orbitrap ESI tandem MS/MS). These metabolites were characterized by analysis of their exact molecular masses and corresponding fragmentation patterns. The retention times of the identified metabolites were compared with those of standard compounds, confirming the presence of naturally occurring bioactive compounds. Density Functional Theory (DFT) calculations were employed to investigate preferential deprotonation sites in representative polyprotic metabolites. All these findings may contribute to expanding the spectrum of compounds identified within the genus Hypotrachyna and to evaluating their potential biological activities.

To create high-performance cutting fluids, it has been suggested to make use of nanofluids, provided that these fluids are devoid of potentially harmful contaminants and that they possess adequate lubricating and cooling properties. Both the production of a graphene nanoplatelet-based nanofluid from palm oil and the testing of this nanofluid were carried out with the assistance of minimum quantity lubrication. Significant improvements have been made to both the anti-wear capabilities of the Ti6Al4V/ZrO2 tribo-anti-friction pair as well as the nanofluid/minimum quantity lubrication mode, which is founded on palm oil. Specific cutting energy was found to be lowered by 93.49% when utilizing a nanofluid composed of graphene nanoplatelets at a weight concentration of 0.1% compared to dry circumstances, and by 90.889% when using commercially available high-performance minimum quantity lubrication. To achieve these outcomes, a graphene nanoplatelet-based nanofluid with a concentration of only 0.1% by weight was used. Grinding cutting forces were reduced by using a nanofluid containing 0.1% by weight of graphene nanoplatelets.

Ten new thiosemicarbazone derivatives, furan-2-carbaldehyde thiosemicarbazone (1), 3-methyl-furan-2-carbaldehyde thiosemicarbazone (2), 5-hydroxymethyl-furan-2-carbaldehyde thiosemicarbazone (3), 5-trifluoromethyl-furan-2-carbaldehyde thiosemicarbazone (4), 5-nitro-furan-2-carbaldehyde thiosemicarbazone (5), 5-phenyl-furan-2-carbaldehyde thiosemicarbazone (6), 5-(2-fluorophenyl)-furan-2-carbaldehyde thiosemicarbazone (7), 5-(4-methoxyphenyl)-furan-2-carbaldehyde thiosemicarbazone (8), 5-(1-naphthyl)-furan-2-carbaldehyde thiosemicarbazone (9), and 5-(1H-Pyrazol-5-yl)-furan-2-carbaldehyde thiosemicarbazone (10) were synthesized by condensing thiosemicarbazide with the respective furan-2-carbaldehyde in methanol. The prepared compounds were characterized by spectroscopic studies (FT-IR and NMR) and electrospray mass spectrometry. The molecular structures of 2, 6, 7, and 8 have also been determined by X-ray crystallography. Compounds 2, 6, and 7 crystallize in the E conformation about the N1-C6, N1-C11, and N1-C11 bonds, respectively, while 8 adopts the Z conformation about the N1-C12 bond with the presence of an intramolecular N2-H…O2 hydrogen bond. All prepared thiosemicarbazone derivatives were evaluated for their in vitro antibacterial, antifungal, and antitumor activities against Staphylococcus aureus strains, Candida albicans/Candida tropicalis fungi, and seven human tumor cell lines (HuTu80, H460, DU145, M-14, HT-29, MCF-7, and LNCaP), respectively. The antioxidant activity was also studied by the DPPH assay. Compound 5 exhibited significant antibacterial activity against Staphylococcus aureus ATCC700699 (MIC = 1 μg/mL) compared to the nitrofurantoin and gentamicin reference drugs (MIC = 1–25 and 10->100 μg/mL, respectively). Compound 4 was ten times less active than amphotericin B (MIC = 5 μg/mL) against Candida albicans (ATCC90028 and ATCC10231), while 1 exhibited a moderate effect of scavenging of DPPH radical (IC50 = 40.9 μg/mL) in comparison to ascorbic acid reference compound (IC50 = 22.0 μg/mL). Among all the studied thiosemicarbazones, 5 showed a higher cytotoxic activity (IC50 = 13.36–27.73 μΜ) in relation to the other tested compounds (IC50 = 34.84—>372.34 μΜ) against all tested cell lines, except the LNCaP cell line, exhibiting its highest antiproliferative activity (IC50 = 13.36 μΜ) on the HuTu80 cell line. Besides, 8 and 9 exhibited high antitumor activity (IC50 = 13.31 and 7.69 μΜ, respectively) against the LNCaP cells.

Six new phenyl‐1 H ‐pyrazole‐carbaldehyde isonicotinylhydrazone derivatives 1-10 were synthesized and characterized by spectroscopic (FT‐IR, 1H NMR, and 13C NMR) techniques and electrospray ionization–mass spectrometry (ESI–MS). Homonuclear data from 2D‐NMR ( 1 H‐ 1 H NOESY) revealed that 3 and 5 adopt the transE isomeric form. The in vitro antitubercular activity of all the synthesized compounds was determined against Mycobacterium tuberculosis (sensitive H37RV and resistant TB DM97). With respect to the isoniazid (INH) standard drug (MIC = 0.91 μM), all the prepared compounds showed greater antitubercular activity with MIC values in the range of 0.38–0.82 μM against Mtb H37Rv‐sensitive strain. However, the preliminary results indicated that Compounds 1 – 10 tested against the TB DM97‐resistant strain showed low bioactivity. The optimized geometry of Compounds 1 – 10 has been determined by density functional theory (DFT) calculations. For Compounds 1 – 6 , the most stable isomers (in DMSO) exhibited an E geometrical configuration, while Compounds 7–10 exhibited a Z configuration. The global reactivity values indicate that Compounds 1 – 10 are slightly more reactive and less stable than the standard (INH). Additionally, they exhibit a strong binding capacity to biomolecules, comparable to INH. The MEP map reveals that the negative and positive potential sites are predominantly located on the C=O and HN–NH groups, respectively, similar to those observed for INH. Drug‐likeness and ADME properties were evaluated. All compounds showed adequate ADME properties and are drug‐like. Molecular docking studies (Compounds 1 – 10 ) into the active site of mycobacterial InhA showed an acceptable dissociation constant with improved binding energy (from −6.7 to −8.1 kcal mol −1 ) compared to isoniazid (−5.6 kcal mol −1 ). Molecular dynamics simulations revealed that the molecules cmp3 (3) and cmp5 (5) form stable ternary complexes with InhA through persistent hydrogen bonding and hydrophobic interactions. These compounds showed reduced active‐site fluctuations and superior binding free energies compared to INH. The findings represent a significant advancement in the discovery of potential antitubercular agents.

Eight new thiosemicarbazone derivatives, 6-(1-trifluoroethoxy)pyridine-3-carbaldehyde thiosemicarbazone (1), 6-(4′-fluorophenyl)pyridine-3-carbaldehyde thiosemicarbazone (2), 5-chloro-pyridine-3-carbaldehyde thiosemicarbazone (3), 2-chloro-5-bromo-pyridine-3-carbaldehyde thiosemicarbazone (4), 6-(3′,4′-dimethoxyphenyl)pyridine-3-carbaldehyde thiosemicarbazone (5), 2-chloro-5-fluor-pyridine-3-carbaldehyde thiosemicarbazone, (6), 5-iodo-pyridine-3-carbaldehyde thiosemicarbazone (7), and 6-(3′,5′-dichlorophenyl)pyridine-3-carbaldehyde thiosemicarbazone (8) were synthesized, from the reaction of the corresponding pyridine-3-carbaldehyde with thiosemicarbazide. The synthesized compounds were characterized by ESI-Mass, UV-Vis, IR, and NMR (1H, 13C, 19F) spectroscopic techniques. Molar mass values and spectroscopic data are consistent with the proposed structural formulas. The molecular structure of 7 has been also confirmed by single crystal X-ray diffraction. In the solid state 7 exists in the E conformation about the N2-N3 bond; 7 also presents the E conformation in solution, as evidenced by 1H NMR spectroscopy. The in vitro antitumor activity of the synthesized compounds was studied on six human tumor cell lines: H460 (lung large cell carcinoma), HuTu80 (duodenum adenocarcinoma), DU145 (prostate carcinoma), MCF-7 (breast adenocarcinoma), M-14 (amelanotic melanoma), and HT-29 (colon adenocarcinoma). Furthermore, toxicity studies in 3T3 normal cells were carried out for the prepared compounds. The results were expressed as IC50 and the selectivity index (SI) was calculated. Biological studies revealed that 1 (IC50 = 3.36 to 21.35 μM) displayed the highest antiproliferative activity, as compared to the other tested thiosemicarbazones (IC50 = 40.00 to >582.26 μM) against different types of human tumor cell lines. 1 was found to be about twice as cytotoxic (SI = 1.82) than 5-fluorouracile (5-FU) against the M14 cell line, indicating its efficiency in inhibiting the cell growth even at low concentrations. A slightly less efficient activity was shown by 1 towards the HuTu80 and MCF7 tumor cell lines, as compared to that of 5-FU. Therefore, 1 can be considered as a promising candidate to be used as a pharmacological agent, since it presents significant activity and was found to be more innocuous than the 5-FU anticancer drug against the 3T3 mouse embryo fibroblast cells.

Six novel phenylisoxazole semicarbazone derivatives 1 – 6 were synthesized by reaction of the corresponding phenylisoxazole‐3/5‐carbaldehyde derivatives with semicarbazide hydrochloride. The synthesized compounds were characterized by ESI‐MS, FT‐IR, and NMR ( 1 H, 13 C) spectroscopic techniques. The two‐dimensional 1 H‐ 1 H NOESY NMR (in acetone‐ d 6 ) data revealed that compound 1 exists in the E isomeric form. The computational study of the energetic, structural, and electronic properties, carried out at B3LYP/6‐311G++(d,p) level of theory, showed that the most stable conformer for the all synthesized compounds, in both gas and liquid (acetone and DMSO) phases, has a cisE geometrical configuration. This evidence found is in good agreement with the spectrometric results. The geometrical parameters, frontier molecular orbital (FMO), molecular electrostatic potential (MEP), Mulliken atomic charges, and natural bonding orbital (NBO) analysis were also performed at the same level of theory. Taking into account the relative enthalpies Δ H computed, we can establish for tautomeric structures of each of the compounds, the following stability order: I ( cisE ) > II ( E ′ E ) > III ( cisE ). The MEP descriptors indicate that the oxygen atom of the carbonyl group C=O is susceptible to electrophilic attack, while the hydrogen atoms of the amide and hydrazone fragments are sensitive to nucleophilic attack. The calculated HOMO‐LUMO gap energies E g indicate that 5 (in gas phase) and 6 (in liquid phase) are the most stable and less reactive compounds, while 1 is the less stable and the most reactive compound. From the NBO analysis, it becomes evident that the presence of the hydrazone fragment produces stabilizing effects due to hyperconjugative interactions.

The density-functional theory is widely used to predict the physical properties of materials. However, it usually fails for strongly correlated materials. A popular solution is to use the Hubbard correction to treat strongly correlated electronic states. Unfortunately, the values of the Hubbard U and J parameters are initially unknown, and they can vary from one material to another. In this semi-empirical study, we explore the U and J parameter space of a group of iron-based compounds to simultaneously improve the prediction of physical properties (volume, magnetic moment, and bandgap). We used a Bayesian calibration assisted by Markov chain Monte Carlo sampling for three different exchange-correlation functionals (LDA, PBE, and PBEsol). We found that LDA requires the largest U correction. PBE has the smallest standard deviation and its U and J parameters are the most transferable to other iron-based compounds. Lastly, PBE predicts lattice parameters reasonably well without the Hubbard correction.

Four indole-3-carbaldehyde semicarbazone derivatives, 2-((5-bromo-1H-indol-3-yl)methylene)hydrazinecarboxamide (1), 2-((5-chloro-1H-indol-3-yl)methylene)hydrazinecarboxamide (2), 2-((5-methoxy-1H-indol-3-yl)methylene)hydrazinecarboxamide (3), and 2-((4-nitro-1H-indol-3-yl)methylene)hydrazinecarboxamide (4) were synthesized and characterized by ESI-MS and spectroscopic (FT-IR, 1H NMR, and 13C NMR) techniques. The two-dimensional NMR (in acetone-d6) spectral data revealed that the molecules 1 and 2 in solution are in the cisE isomeric form. This evidence is supported by DFT calculations at the B3LYP/6-311++G(d,p) level of theory where it was shown that the corresponding most stable conformers of the synthesized compounds have a cisE geometrical configuration, in both the gas and liquid (acetone and DMSO) phases. The in vitro antibacterial activity of compounds 1–4 was determined against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. Among all the tested semicarbazones, 1 and 2 exhibited similar inhibitory activities against Staphylococcus aureus (MIC = 100 and 150 μg/mL, respectively) and Bacillus subtilis (MIC = 100 and 150 μg/mL, respectively). On the other hand, 3 and 4 were relatively less active against the tested bacterial strains compared with 1, 2, and tetracycline.

Eight new phenylisoxazole isoniazid derivatives, 3-(2′-fluorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (1), 3-(2′-methoxyphenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (2), 3-(2′-chlorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (3), 3-(3′-clorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (4), 3-(4′-bromophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (5), 5-(4′-methoxiphenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (6), 5-(4′-methylphenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (7), and 5-(4′-clorophenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (8), have been synthesized and characterized by FT-IR, 1H-NMR, 13C-NMR, and mass spectral data. The 2D NMR (1H-1H NOESY) analysis of 1 and 2 confirmed that these compounds in acetone-d6 are in the trans(E) isomeric form. This evidence is supported by computational calculations which were performed for compounds 1–8, using DFT/B3LYP level with the 6-311++G(d,p) basis set. The in vitro antituberculous activity of all the synthesized compounds was determined against the Mycobacterium tuberculosis standard strains: sensitive H37Rv (ATCC-27294) and resistant TB DM97. All the compounds exhibited moderate bioactivity (MIC = 0.34–0.41 μM) with respect to the isoniazid drug (MIC = 0.91 μM) against the H37Rv sensitive strain. Compounds 6 (X = 4′-OCH3) and 7 (X = 4′-CH3) with MIC values of 12.41 and 13.06 μM, respectively, were about two times more cytotoxic, compared with isoniazid, against the resistant strain TB DM97.

The manufacturing industry aims to produce many high quality products efficiently at low cost, thereby motivating companies to use advanced manufacturing technologies. The use of high-speed machining is increasingly widespread; however, it lacks a deep-rooted knowledge base needed to facilitate implementation. In this paper, response surface methodology (RSM) has been applied to determine the optimum cutting conditions leading to minimum flank wear in high-speed dry turning on AISI 1045 steel. The mathematical models in terms of machining parameters were developed for flank wear prediction using RSM on the basis of experimental results. The high speed turning experiments were carried out with two coated carbide and a cermet inserts using AISI 1045 steel as work material at different cutting speeds and machining times. The models selected for optimization were validated through the Pareto principle. Results showed the GC4215 insert to be the most optimal option, because it did not reach the cutting tool life limit and could be used for the whole range of cutting parameters selected. To quantitatively evaluate the usefulness of the cutting tools, it was proposed the coefficient of use of the tools from the results of the contour graphs. The GC4215 insert showed 100% effectiveness, followed by the GC4225 with 98.4%, and finally, the CT5015 insert with 83%.