Search Results (4,141)

Drug discovery is a complex and expensive process in which only a small proportion of candidate molecules reach clinical approval. Computational methods, particularly computer-aided drug design (CADD), have become fundamental to accelerate and optimize early stages of discovery by integrating chemical, biological, and pharmacokinetic information into predictive models. This review outlines a complete computational workflow for chemical compound analysis, covering molecular structure generation, database selection, evaluation of absorption, distribution, metabolism, excretion and toxicity (ADMET), target prediction, and molecular docking. It focuses on freely accessible and web-based tools that enable reproducible, cost-effective, and scalable in silico studies. Key platforms such as PubChem, ChEMBL, RDKit, SwissADME, TargetNet, and SwissDock are highlighted as examples of how different resources can be integrated to support rational compound design and prioritization. The article also discusses essential methodological principles, data curation strategies, and common limitations in virtual screening and docking analyses. Finally, it explores future directions in computational drug discovery, including the incorporation of artificial intelligence, multi-omics integration, and quantum simulations, to enhance predictive accuracy and translational relevance. Full article

This study investigates the use of the fine fraction of Brazilian residual kaolin, a material with no pozzolanic activity according to the modified Chapelle test, as a partial cement replacement in rendering mortars. The kaolin was classified into three granulometric fractions (coarse: 150–300 µm, intermediate: 75–150 µm, and fine: <75 µm) and incorporated at two filler contents (10% and 20% by weight). Mineralogical and chemical analyses revealed that the fine fractions contained higher proportions of kaolinite and accessory oxides, while medium and coarse fractions were dominated by quartz. Intensity ratios from XRD confirmed greater structural disorder in the fine fraction, which was associated with higher water demand but also improved particle packing and pore refinement. Fresh state tests showed that mortars with fine kaolin maintained higher density and exhibited moderate increases in air content, whereas medium and coarse fractions promoted greater entrainment. In the hardened state, fine kaolin reduced water absorption by immersion and capillary rise, while medium and coarse fractions led to higher porosity. Mechanical tests confirmed these trends: although compressive and flexural strengths decreased with increasing substitution, mortars containing the fine kaolin fraction consistently exhibited more moderate strength losses than those with medium or coarse fractions, reflecting their enhanced packing efficiency and pore refinement. Tensile bond strength results further highlighted the positive contribution of the kaolin additions, as the mixtures with 10% coarse kaolin and 20% fine kaolin achieved adhesion values only about 7% and 4% lower, respectively, than the control mortar after 28 days. All mixtures surpassed the performance requirements of NBR 13281, demonstrating that the incorporation of residual kaolin—even at higher substitution levels—does not compromise adhesion and remains compatible with favorable cohesive failure modes in the mortar layer. Despite the lack of pozzolanic activity, residual kaolin was used due to its filler effect and capacity to enhance particle packing and pore refinement in rendering mortars. A life cycle assessment indicated that the partial substitution of cement with residual kaolin effectively reduces the environmental impacts of mortar production, particularly the global warming potential, when the residue is modeled as a by-product with a negligible environmental burden. This highlights the critical role of methodological choices in assessing the sustainability of industrial waste utilization. Full article

Stone cultural relics are primarily composed of sandstone, a water-sensitive rock that is highly susceptible to deterioration from environmental solutions and dry-wet cycles. Sandstone pagodas are often directly exposed to natural elements, posing significant risks to their preservation. Therefore, it is crucial to investigate the performance of sandstone towers in complex solution environments and understand the degradation mechanisms influenced by multiple environmental factors. This paper focuses on the twin towers of the Huachi Stone Statue in Qingyang City, Gansu Province, China, analyzing the changes in chemical composition, surface/microstructure, physical properties, and mechanical characteristics of sandstone under the combined effects of various solutions and dry-wet cycles. The results indicate that distilled water has the least effect on the mineral composition of sandstone, while a 5% Na₂SO₄ solution can induce the formation of gypsum (CaSO₄·2H₂O). An acidic solution, such as sulfuric acid, significantly dissolves calcite and diopside, leading to an increase in gypsum diffraction peaks. Additionally, an alkaline solution (sodium hydroxide) slightly hydrolyzes quartz and albite, promoting calcite precipitation. The composite solution demonstrates a synergistic ion effect when mixed with various single solutions. Microstructural examinations reveal that sandstone experiences only minor pulverization in distilled water. In contrast, the acidic solution causes micro-cracks and particle shedding, while the alkaline solution results in layered spalling of the sandstone surface. A salt solution leads to salt frost formation and pore crystallization, with the composite solution of sodium hydroxide and 5% Na₂SO₄ demonstrating the most severe deterioration. The sandstone is covered with salt frost and spalling, exhibiting honeycomb pores and interlaced crystal structures. From a physical and mechanical perspective, as dry-wet cycles increase, the water absorption and porosity of the sandstone initially decrease slightly before increasing, while the longitudinal wave velocity and uniaxial compressive strength continually decline. In summary, the composite solution of NaOH and 5% Na₂SO₄ results in the most significant deterioration of sandstone, whereas distilled water has the least impact. The combined effects of acidic/alkaline and salt solutions generally exacerbate sandstone damage more than individual solutions. This study offers insights into the regional deterioration characteristics of the Huachi Stone Statue Twin Towers and lays the groundwork for disease control and preventive preservation of sandstone cultural relics in similar climatic and geological contexts. Full article

New alternatives in the construction industry are essential for economic, sustainable, and environmental progress. In this context, this work investigated three sets of sustainable mortars incorporating industrial lamination waste, assessing their chemical, physical, microstructural, and mechanical properties to inform their development. Cylindrical and prismatic specimens were produced using the following incorporation methods: a reference mortar, mortars with mill scale addition, partial cement replacement with mill scale, and partial sand replacement with mill scale, at proportions of 10%, 20%, 30%, 40%, and 50%. Additionally, analyses including X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) were performed. Physical and mechanical tests, including bulk density, consistency index, capillary water absorption, axial compressive strength, and flexural tensile strength, were also conducted. XRF results indicated an increase in iron oxide content and a decrease in calcium oxide with the addition of mill scale. XRD confirmed the presence of compounds, such as alite and portlandite, which are common in cementitious mortars. FTIR spectra exhibited characteristic functional groups through absorption bands related to Si–O stretching. SEM micrographs revealed slight morphological changes in the composites as the quantity of industrial lamination waste increased, and EDS data supported the XRF findings. The addition of industrial lamination waste affected the spread index and density of the mixtures, while capillary water absorption decreased in some formulations with mill scale. The strength of the mortars increased with the incorporation of industrial lamination waste. In conclusion, using industrial lamination waste in mortars is a technically and environmentally feasible alternative that aligns with the principles of sustainable development and the circular economy in the construction industry. Full article

We report the synthesis and multifunctional characterization of copper-reinforced Ba_0.85Sr_0.15TiO₃ (BST) ceramic composites with Cu contents ranging from 0 to 40 wt%, prepared by a sol–gel route and densified using spark plasma sintering (SPS). X-ray diffraction and FT-IR analyses confirm the coexistence of cubic and tetragonal BST phases, while Cu remains as a chemically separate metallic phase without detectable interfacial reaction products. Microstructural observations reveal abnormal grain growth induced by localized liquid-phase-assisted sintering and progressive Cu agglomeration at higher loadings. Scanning electron microscopy reveals abnormal grain growth, with the average BST grain size increasing from approximately 3.1 µm in pure BST to about 5.2 µm in BST–Cu40% composites. Optical measurements show a continuous reduction in the effective optical bandgap (apparent absorption edge) from 3.10 eV for pure BST to 2.01 eV for BST–Cu40%, attributed to interfacial electronic states, defect-related absorption, and enhanced scattering rather than Cu lattice substitution. Electrical characterization reveals a percolation threshold at approximately 30 wt% Cu, where AC conductivity and dielectric permittivity reach their maximum values. Impedance spectroscopy and equivalent-circuit analysis demonstrate strong Maxwell–Wagner interfacial polarization, yielding a maximum permittivity of ~1.2 × 10⁵ at 1 kHz for BST–Cu30%. At higher Cu contents, conductivity and permittivity decrease due to disrupted Cu connectivity and increased porosity. These findings establish BST–Cu composites as tunable ceramic–metal systems with enhanced dielectric and optical responses, demonstrating potential for specialized high-capacitance decoupling applications where giant permittivity is prioritized over low dielectric loss. Full article

Brazil is one of the richest countries in biodiversity, with biomes that host countless native species of ecological and economic relevance. Among its native fruits, mangaba (Hancornia speciosa) stands out for its nutritional relevance. However, its industrial use remains limited by seasonality, perishability, and harvesting difficulties. This study evaluated the effects of different drying techniques—convective (CD), microwave (MWD), and infrared (IRD)—on the physical and chemical properties of mangaba pulp microcapsules obtained by ionic gelation, including drying kinetics. Drying time varied markedly among treatments, ranging from 25 (MWD) to 185 (IRD) min. In general, the Page modified model provided the best fit for drying kinetics. Physical analyses revealed that IRD produced microcapsules with higher wettability (43.33 s), lower hygroscopicity (203.01 g/100 g), and higher bulk (0.382 g/cm³) and particle density (1.339 g/cm³). CD resulted in greater dispersibility (248.45%) and porosity (0.732), whereas MWD showed the lowest water absorption index (1.78). Regarding bioactive compounds, IRD retained the highest ascorbic acid content, CD preserved more antioxidant activity, and MWD presented the highest total phenolic content. Overall, despite the different processes, mangaba microcapsules retained relevant levels of bioactive compounds, confirming the potential of ionic gelation combined with drying as an effective preservation strategy. Full article

The Sar-e-Sang lapis lazuli deposit has a mining history exceeding 5000 years, producing the world’s finest lapis lazuli. Recently, gem-quality forsterite has been discovered in the marble containing spinel, dolomite, and phlogopite at the periphery of the lapis lazuli ore body at the Pitawak mine, located east of the Sar-e-Sang deposit. The mineral assemblage indicates that the protolith of this marble is dolomite with aluminous and siliceous components. These forsterite crystals occur as colorless, transparent anhedral grains, exhibiting distinct red fluorescence under 365 nm ultraviolet light. To investigate the gemological and spectroscopic characteristics of the Pitawak mine forsterite, this study conducted and analyzed data from basic gemological analysis, electron probe microanalysis (EPMA), Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), ultraviolet–visible absorption spectroscopy (UV-VIS), Fourier-transform infrared spectroscopy (FTIR), laser Raman spectroscopy (RAMAN), and photoluminescence spectroscopy (PL) on four forsterite samples from the Pitawak mine. The analysis results reveal that the samples indicate a composition close to ideal forsterite with a crystal chemical formula of (Mg_2.00Fe_0.02)_Σ2.02Si_0.99O₄. The trace elements present include Fe, Mn, Ca, and minor amounts of Cr and Ni. The UV-VIS spectroscopy results show that the samples possess high transmittance across the visible light range with very weak absorption bands, contributing to the colorless and transparent appearance of Pitawak mine forsterite. This phenomenon is attributed to the extremely low content of chromophoric elements, which have a negligible effect on the forsterite’s color. PL spectroscopy indicates that the red fluorescence of the samples is caused by an emission peak near 642 nm. This emission peak arises from the spin-forbidden ⁴T₁ → ⁶A₁ transition of Mn²⁺ ions situated in octahedral sites within the forsterite structure. Full article

CO₂ laser processing has emerged as an efficient dry-finishing technique capable of inducing controlled chemical and morphological transformations in cotton and denim textiles. The strong mid-infrared absorption of cellulose enables localised photothermal heating, leading to selective dye decomposition, surface oxidation, and micro-scale ablation while largely preserving the bulk fabric structure. These laser-driven mechanisms modify colour, surface chemistry, and topography in a predictable, parameter-dependent manner. Low-fluence conditions predominantly produce uniform fading through fragmentation and oxidation of indigo dye; in comparison, moderate thermal loads promote the formation of carbonyl and carboxyl groups that increase surface energy and enhance wettability. Higher fluence regimes generate micro-textured regions with increased roughness and anchoring capacity, enabling improved adhesion of dyes, coatings, and nanoparticles. Compared with conventional wet processes, CO₂ laser treatment eliminates chemical effluents, strongly reduces water consumption and supports digitally controlled, Industry 4.0-compatible manufacturing workflows. Despite its advantages, challenges remain in standardising processing parameters, quantifying oxidation depth, modelling thermal behaviour, and assessing the long-term stability of functionalised surfaces under real usage conditions. In this review, we consolidate current knowledge on the mechanistic pathways, processing windows, and functional potential of CO₂ laser-modified cotton substrates. By integrating findings from recent studies and identifying critical research gaps, the review supports the development of predictable, scalable, and sustainable laser-based cotton textile processing technologies. Full article

Sulfidized nano zero-valent iron (S-nZVI) particles are known to stimulate the reductive removal of various oxyanions due to enhanced electron selectivity and electron conductivity between the Fe(0) core and the target compound. Sulfidation creates a number of reactive sulfur species, the role of which has not yet been investigated in the context of S-nZVI. In this study, we investigated the contribution of reactive sulfur species to Se(VI) reduction by S-nZVI at different molar S/Fe ratios (0, 0.1 and 0.6) and Se(VI) concentrations (0, 5 and 50 mg L⁻¹). In the presence of S-nZVI, the rate of reduction was accelerated by a factor of up to ten. X-ray Absorption Near-Edge Structure (XANES) spectroscopy and surface-sensitive X-ray photoelectron spectroscopy (XPS) identified Se(0) as the predominant reduction product (~90%). The reduction reaction was accompanied by a loss of FeS and the formation of surface-bound Fe(II) polysulfide (FeSx) and S(0) species. Likewise, wet chemical extraction techniques suggested a direct involvement of acid volatile sulfide (AVS) species (surface-bound FeS) in the reduction of Se(IV) to Se(0) and formation of S(0). Mass balance estimates reveal that between 9 and 15% of the conversion of Se(0) originates from oxidation of FeS to FeSx. From these findings, we propose that surface-bound Fe sulfide species are important but previously overlooked reactants contributing to the reduction of oxyanions associated with S-nZVI particles, as well as in natural environments undergoing sulfidation reactions. Full article

This study examined the influence of short-term olive fruit storage on the quality of virgin olive oil (VOO) from three cultivars (‘Kalinjot’, ‘Leccino’, and ‘Frantoio’) grown in southwest Albania. Olive fruits were processed immediately after harvest, or after 10 days of storage under ambient conditions (20–22 °C) and refrigeration (5 °C). Oils were evaluated for physicochemical quality parameters (free acidity, peroxide value, and UV absorption indices), as well as bioactive and sensory-related compounds (bitterness index, chlorophylls, carotenoids, and total phenolic content). Results showed that immediate processing yielded the highest quality oils, with low free acidity (0.28–0.35%) and preserved bioactive compounds. Ambient storage led to marked deterioration, including significant increases in free acidity and peroxide values, loss of pigments, and 20–70% reduction in phenolic content, accompanied by decreased bitterness. In contrast, cold storage mitigated these effects, maintaining values closer to baseline and preserving sensory and functional attributes. ANOVA confirmed significant effects of storage duration, temperature, and cultivar on most parameters, with ‘Kalinjot’ exhibiting greater stability compared to ‘Frantoio’ and ‘Lecino’. These findings highlight that minimizing the interval between harvest and milling is critical for ensuring oil quality, while refrigerated storage offers a practical strategy to safeguard chemical and sensory characteristics when immediate processing is not feasible. Full article

Cadmium sulfide is an important II-VI semiconductor known for its valuable photocatalytic properties ascribable to its band gap energy, which allows light absorption in the visible domain. Nonetheless, the application of cadmium sulfide in wastewater organic pollutant degradation is restricted due to its high toxicity to humans, soil, and marine life. To address this issue, we developed new composite materials by depositing CdS on a bentonite support in a 1:9 mass ratio to develop a photocatalyst with lower toxicity. In the first step, bentonite was activated using an aqueous HCl solution; for the deposition of CdS powder, we proposed the trituration method and compared it with chemical precipitation and hydrothermal synthesis, using thioacetamide as a sulfide ion source. The modified bentonite underwent characterization using X-ray diffraction, scanning electron microscopy, X-ray fluorescence, UV-Vis, and FTIR spectroscopy. The photocatalytic activity was tested in the degradation of Congo red (CR), a persistent diazo dye. The efficiency of removing CR with CdS–bentonite composites depended on the deposition method of CdS, and it was higher than that of pristine CdS and of only adsorption onto acid-activated bentonite. The photocatalytic degradation mechanism was estimated by the scavenger test using ethylenediaminetetraacetic acid disodium salt, ascorbic acid, ethanol, and silver nitrate as radical scavengers. Full article

An optical fiber chemical sensor using a molecularly imprinted chitosan membrane coated on the surface of a bent optical fiber probe was developed for selectively analyzing 4-nitrophenol (4-NP) in water samples. When the sensor probe is exposed to a water sample, the chitosan MIP membrane extracts/concentrates 4-NP from the water sample into the membrane. The 4-NP extracted into the membrane was detected by passing a light beam through the optical fiber and the interaction of the 4-NP in the membrane with an evanescent wave of light guided through the optical fiber was detected as a sensing signal. This sensor detects the intrinsic optical absorption signal of 4-NP itself as a sensing signal. No chemical reagent was needed in analyzing this compound in a sample. The sensor is reversible, can be used for continuous monitoring of 4-NP in a sample, and has a quick response with a response time of 5 min. The sensor has high sensitivity and selectivity because the MIP membrane selectively concentrates 4-NP by 1.4 × 10⁴ times into the membrane from a sample solution, but blocks out interference species, including its isomers and derivatives, from entering the membrane. The sensor achieved a detection limit of 2.5 ng/mL (0.018 µM), which is lower than most reported analytical techniques for analyzing this compound in water samples. This sensor can discriminate 4-NP from its isomers and derivatives, such as 2-NP, 3-NP, 2-Cl-4-NP, and 2,4-di-NP, with a selectivity factor ranging from 104 to 1922. This is the first reported case of an MIP-based optical fiber chemical sensor with the capability of discriminating an organic compound from its closely related positional isomers, which demonstrates the high selectivity nature of the MIP-based optical fiber chemical sensor technique. The sensor has been used for analyzing 4-NP in a standard addition sample. The obtained recovery rate ranged from 93% to 101%, demonstrating the application potential of this sensor in water quality analysis. Full article

Objective: Echinacea purpurea, an herb with diverse pharmacological activities, has its roots widely used for anti-inflammatory and immunomodulatory purposes. Interestingly, its aerial parts, which are also rich in bioactive compounds, remain underutilized. This study aims to optimize the extraction and purification processes to obtain the aerial part extract of Echinacea purpurea (APE-EP) to enhance the content of active constituents and improve its anti-inflammatory and immunomodulatory effects. Methods: We analyzed the chemical composition of APE-EP using HPLC-MS. The intestinal absorption characteristics of APE-EP were evaluated using an ex vivo everted gut sac assay. Furthermore, the anti-inflammatory and immunomodulatory effects of APE-EP were validated using a DSS-induced colitis mouse model. Results: Several phenolic acids were identified, including chicoric acid and caffeic acid, which have significant antioxidant and anti-inflammatory activities. The everted gut sac assay revealed concentration-dependent absorption of chicoric acid in the gut. Results from the mouse model showed that APE-EP promoted macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 macrophages at the lesion sites, effectively suppressing inflammation and alleviating colitis-related pathological damage. Conclusions: This study enhances the medicinal value of the E. purpurea, provides new insights for the efficient utilization of plant resources, and offers a potential natural drug candidate for inflammatory bowel disease treatment. Full article

Metformin, a 60-year-old biguanide and cornerstone of type 2 diabetes therapy, continues to challenge and inspire modern pharmaceutical science. Despite its chemical simplicity, metformin displays highly complex pharmacokinetic and pharmacodynamic behavior driven by transporter dependence, luminal activity, and formulation-sensitive exposure. Originally regarded as limited by low permeability and incomplete absorption, metformin has emerged as a paradigm for gut-targeted therapy, controlled- and delayed-release systems, and personalized pharmaceutics. Growing evidence has repositioned the intestine, rather than systemic plasma exposure, as a major site of action, highlighting the central role of organic cation transporters and multidrug efflux systems in determining efficacy, variability, and gastrointestinal tolerability. Beyond metabolic control, insights into transporter regulation, pharmacogenetics, microbiome interactions, and manufacturing quality have expanded metformin’s relevance as a model compound for contemporary drug development. Advances in formulation design, quality-by-design manufacturing, and regulatory control have further reinforced its clinical robustness, while repurposing efforts in oncology, immunometabolism, and regenerative medicine underscore its translational potential. This review integrates mechanistic pharmacology, formulation science, and clinical translation to position metformin not merely as an antidiabetic agent, but as a didactic model illustrating the evolution of pharmaceutics from molecule-centered design to system-oriented, precision-driven therapy. Full article

Vanadyl octa-(4-tert-butylphenyl)phthalocyanine (VOPc(t-BuPh)₈) and vanadyl octa-(4-tert-butylphenyl)tetrapyrazinoporphyrazine (VOTPyzPz(t-BuPh)₈) complexes were synthesized for the first time and confirmed by IR and UV-Vis spectroscopy and MALDI-TOF spectrometry. The method of synthesis of their precursors, 4,5-bis(4-tert-butylphenyl)phthalonitrile ((t-BuPh)₂PN) and 5,6-bis(4-tert-butylphenyl)pyrazine-2,3-dicarbonitrile ((t-BuPh)₂PDC), was modified, resulting in higher yields. For the vanadyl complexes, the basic properties were studied, and it was found that the red shift in the Q band in the first protonation step is approximately two times greater than that of previously known complexes. An electrochemical study showed the influence of aza-substitution on the redox properties and on the energies of the frontier orbitals of all the compounds presented. For all four considered compounds, quantum chemical calculations of the molecular structure, IR spectra, and electronic absorption spectra were carried out using density functional theory (DFT) and time-dependent density functional theory (TDDFT and simplified sTDDFT) approaches. According to the DFT calculations, vanadyl macrocyclic complexes have dome-shaped distorted structures. Experimental and theoretical IR and electronic absorption spectra were compared and interpreted. Full article