Synthesis and Sintering

Artificial intelligence-guided biosynthesis and retrosynthesis in pharmacognosy: Toward the synthesis-oriented discovery of natural-product therapeutics

Kiarash Solouki, Niloufar Moharrer Navaei, Ayla Balkan — Mon, 15 Jun 2026 00:00:00 -0300

Artificial intelligence is reshaping Pharmacognosy by connecting ethnobotanical knowledge, multi-omic data, Biosynthetic pathway prediction, Retrosynthetic planning, and medicinal chemistry optimization. Particular attention is given to AI-driven tools, including BioNavi-NP, graph-sequence-enhanced transformers, NAG2G, RSGPT, RetroExplainer, and human-in-the-loop systems such as DeepRetro. These platforms can reconstruct natural-product biosynthesis, predict plausible precursors, preserve molecular topology, suggest multi-step disconnections, and explore broad reaction spaces. They are especially relevant for metabolites with dense stereochemistry, unusual ring systems, multifunctional scaffolds, and enzyme-guided biosynthetic logic. Beyond route design, AI may help prioritize biosynthetic genes, optimize scarce plant-derived compounds, and guide the development of more drug-like analogues with improved potency, selectivity, pharmacokinetic behavior, and synthetic accessibility. However, important limitations remain, including limited plant-specific reaction datasets, weak reaction-condition prediction, incomplete stereochemical and regioselective modeling, benchmark weaknesses, and the need for expert validation. Overall, AI is best understood as a decision-support layer linking biodiversity, traditional knowledge, biosynthetic logic, and experimental synthesis for responsible future therapeutic discovery and validation across modern natural-product-based drug discovery pipelines.

Corrosion behavior and in-vitro bioactivity of Ti-based composites: Synergistic and competitive effects of ZrO2 and nHA ceramic reinforcements

Shaghayegh Habibi Anganeh, Vahideh Shahedifar, Bahere Tekyeh Marouf — Mon, 15 Jun 2026 00:00:00 -0300

The present study introduces a comparative and synergistic evaluation of corrosion behavior and in-vitro bioactivity of Ti-based composites reinforced with zirconia (ZrO₂) and/or nano-hydroxyapatite (nHA). Pure Ti, Ti–10 vol% nHA (TH), Ti–4 vol% ZrO₂ (TZ), and Ti– 4 vol% ZrO₂–6 vol% nHA (TZH) were fabricated via spark plasma sintering (SPS) at 1200 °C under vacuum to elucidate the individual and combined effects of ceramic phases on passive film formation and degradation mechanisms. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were performed after short-term and 14-day immersion in simulated body fluid (SBF). The TH composite exhibited the lowest corrosion current density (9.22 × 10^-6 mA/cm²) and highest polarization resistance (2910 kΩ.cm²), confirming the formation of a dense, stable Ca–P/TiO₂ multilayer that effectively blocked electrolyte penetration. EIS analysis further revealed the formation of a stable, highly capacitive passive layer on the TH sample, characterized by phase angles near -80° and impedance values up to 1770 kΩ.cm². In contrast, the dual-ceramic TZH composite showed micro-galvanic interactions between ZrO₂ and nHA phases, leading to localized pitting and reduced long-term stability. The TZ sample showed delayed but noticeable improvement in corrosion resistance during prolonged immersion, indicating that ZrO₂ contributes to long-term passivation through the gradual formation of a stable ZrO₂-rich barrier. Long-term immersion tests confirmed apatite formation on all samples, with TH exhibiting the most uniform Ca–P-rich layer, as verified by FE-SEM/EDS. Overall, Ti–10 vol% nHA demonstrated superior corrosion resistance and bioactivity, highlighting its strong potential for orthopedic implant applications.

The expanding role of the Anstis relationship in advanced materials research: A perspective

Maryam Mohammadpour Mokhayer, Mahdiyeh Omrani Khiabanian — Mon, 30 Mar 2026 00:00:00 -0300

Fracture toughness remains one of the most important parameters governing the structural reliability of brittle and quasi-brittle materials. Across a broad-spectrum of 2026 studies, the Anstis relationship continued to serve as one of the most widely adopted methods for evaluating indentation fracture toughness in ceramics, glass-ceramics, thermal barrier coatings, solid electrolytes, high-entropy systems, carbides, borides, composites, geological materials, and additively manufactured structures. The reviewed studies collectively demonstrate that the Anstis relationship remains valuable because it enables fracture toughness estimation from indentation-derived crack lengths while maintaining experimental simplicity and compatibility with heterogeneous or miniature materials systems. The collected publications further reveal a growing integration of fracture toughness evaluation with advanced microstructural engineering strategies including additive manufacturing, spark plasma sintering, eutectic architecture design, high-entropy alloying, defect engineering, phase transformation, residual stress tailoring, and interface-controlled reinforcement. Toughening mechanisms repeatedly observed across the literature include crack deflection, crack bridging, grain refinement, residual compressive stress development, transformation toughening, grain boundary pinning, and multiphase reinforcement. Applications span aerospace systems, thermal/environmental barrier coatings, dental restorations, hydrogen storage alloys, transparent ceramics, radiation shielding glasses, all-solid-state batteries, and ultra-high-temperature structural ceramics. The present perspective integrates fragmented findings from the 2026 excerpts provided into a coherent overview of the expanding role of the Anstis relationship in contemporary materials science research.

Morphology-driven mechanical behavior of sintered titanium: A meso-scale numerical study

Ata Khabaz-Aghdam, Bahati M. Clément, Abuzar E’shagi-Oskui — Mon, 30 Mar 2026 00:00:00 -0300

The mechanical behavior of sintered microstructures is strongly influenced by their underlying morphology, particularly particle arrangement, size distribution, and inter-particle connectivity. In this study, a meso-scale numerical framework was developed to investigate the structure–property relationships of sintered titanium microstructures using randomly generated two-dimensional models. Nine representative configurations with varying overlap levels (5, 10, and 15 μm) were analyzed under directional loading conditions, resulting in a total of eighteen simulations. The results demonstrate, within the adopted two-dimensional meso-scale framework, that increasing particle overlap significantly enhances neck formation, leading to improved load transfer, higher stiffness, and increased strength. Specifically, the Young’s modulus increased from as low as 0.3 GPa in low-overlap cases to values exceeding 60 GPa in highly connected structures, while the ultimate strength reached up to 415 MPa. The coefficient of variation (CV), ranging from 0.15 to 0.30, was found to strongly influence mechanical performance, with higher values promoting heterogeneity, stress concentration, and strain localization. In contrast, increased connectivity (Z_av = 2.00–2.73) improved load distribution and mechanical stability by providing multiple load paths. To capture the combined effects of microstructural heterogeneity, a randomness index (RI = 0.07–0.14) was introduced as a unified descriptor. The RI showed a strong inverse correlation with both stiffness and strength, outperforming individual parameters such as CV and connectivity. Furthermore, the mechanical response was found to be highly anisotropic, with stiffness ratios (E_y/E_x) varying from 0.01 to 4.22 depending on microstructural topology and loading direction. Overall, the findings highlight the critical role of morphology in governing the mechanical performance of sintered microstructures and provide a systematic framework for the design of materials with tailored properties.