Search Results (2,943)

Three-dimensionally (3D)-printed catalytic structures are revolutionizing catalysis and chemical engineering. Unlike traditional supports, modern triply periodic minimal surfaces (TPMS), lattices, and fractals actively influence mass and heat transfer and flow distribution. This review summarizes advancements in the classification, design, fabrication, and application of 3D-printed catalysts over the past decade. The article covers various constructive types (supports, integrated phases, multifunctional reactors) and materials (polymers, ceramics, metals, hybrids), along with fabrication techniques compliant with ISO/ASTM standards (FDM, SLA, DIW, SLM, EBM). It emphasizes post-processing and functionalization strategies (impregnation, calcination, sulfonation) and characterization tools (SAXS, CT, synchrotron-based techniques). A critical comparison highlights advantages, including tunable geometry, improved hydrodynamics, lower pressure drop, enhanced durability, and reproducibility. Three-dimensionally printed catalysts are an interdisciplinary platform combining materials science, chemical engineering, and digital manufacturing. They hold promise for sustainable chemistry, modular production, CO₂ utilization, photocatalysis, and biocatalysis, making them a key innovation for future catalytic reactors. Full article

The C9ORF72 gene mutation is a major cause of amyotrophic lateral sclerosis (ALS). Disease mechanisms involve both loss of C9ORF72 protein function and toxic effects from hexanucleotide repeat expansions. Although its role in neurons and the immune system is well studied, the impact of C9ORF72 deficiency on skeletal muscle is not yet well understood, despite muscle involvement being a key feature in ALS pathology linked to this mutation. This study examined skeletal muscle from C9ORF72 knockout mice and found a 19.5% reduction in large muscle fibers and altered fiber composition. Ultrastructural analysis revealed mitochondrial abnormalities, including smaller size, pale matrix, and disorganized cristae. Molecular assessments showed increased expression of Atrogin-1, indicating elevated proteasomal degradation, and markers of enhanced autophagy, such as elevated LC3BII/LC3BI ratio, Beclin-1, and reduced p62. Mitochondrial quality control was impaired, with a 3.6-fold increase in PINK1, upregulation of TOM20, reduced Parkin, and decreased PGC-1α, suggesting disrupted mitophagy and mitochondrial biogenesis. These changes led to the accumulation of damaged mitochondria. Overall, the study demonstrates that C9ORF72 is critical for maintaining muscle protein and mitochondrial homeostasis. While C9orf72-haploinsufficiency does not directly compromise muscle strength in mice, it may increase the vulnerability of skeletal muscle in C9ORF72-associated ALS. Full article

Cerium-doped titania nanoflowers are obtained by hydrothermal synthesis, with different amounts of cerium (0.3, 0.5, and 1.0 at%). Both undoped nanoflowers (TNF) and Ce-doped TNF (Cex) are tested as photocatalysts in the degradation of the target pollutant (metronidazole) under simulated solar light. The samples are rutile polymorphs with high crystallinity and present a nanoflower-like morphology of about 1 µm in diameter and are made up of nanoscale petals (in the range of 100–300 nm). EDX spectroscopy was coupled with SEM and performed on the Ce-doped samples to determine the elemental composition of the catalysts and the Ce distribution in each sample. Optical and electronic spectroscopies reveal that Ce loading narrows the band gap from 3.0 to 2.8 eV, extending light absorption into the visible range of the spectrum and thus enhancing the photocatalytic activity. The best sample, Ce1, achieved 67% degradation of metronidazole after 360 min under solar irradiation at pH 4, compared to bare TNF, which reached 35%. Reusability tests confirm the chemical stability and photocatalytic efficiency of Ce1 over three cycles, and free-radical trapping experiments confirmed ·O₂⁻ and ·OH as major active species in metronidazole degradation. This study highlights the synergistic impact of morphology and doping on solar-driven organic pollutant degradation. Full article

Crystallography plays a crucial role in understanding the functions of macromolecules by determining their three-dimensional structures at the atomic level. This review outlines the history of crystallization, explains the principles of crystallization, and provides a comprehensive retrospective on the role of crystallography in enzymology, with a particular focus on the seven Enzyme Commission (EC) classes. For each class, we highlight representative enzymes and the specific mechanistic insights enabled by crystal structures, oxidoreductases (the “yellow enzyme” lineage), transferases (phosphotransferase systems), hydrolases (RNase III and chymotrypsin), lyases (fumarase), isomerases (pseudouridine synthases), ligases (E3 ubiquitin ligases), and translocases (ATP synthase), emphasizing cofactor usage, conformational change, regulation, and implications for disease and drug discovery. We also compile EC-wide statistics from the Protein Data Bank (PDB) to quantify structural coverage. The limitations and challenges of current crystallization techniques are addressed, along with alternative experimental methods for structural elucidation. In addition, emerging computational tools and biomolecular design are also discussed. By reviewing the trajectory of enzymology and crystallography, we demonstrated their profound impact on biochemistry and therapeutic discovery. Full article

Metal-free aminobenzoic acid-derived Schiff bases are attractive antimicrobial leads because their azomethine (–C=N–) functionality enables tunable electronic properties and target engagement. We investigated whether halogenation on the phenolic ring would modulate the redox behavior and enhance antibacterial potency, and hypothesized that heavier halogens would favorably tune physicochemical and electronic descriptors. We synthesized three derivatives (SB-3/Cl, SB-4/Br, and SB-5/I) and confirmed their structures using FTIR, ¹H- and ¹³C-NMR, UV-Vis, and HRMS. For SB-5, single-crystal X-ray diffraction and Hirshfeld analysis verified the intramolecular O–H⋯N hydrogen bond and key packing contacts. Cyclic voltammetry revealed an irreversible oxidation (aminobenzoic ring) and, for the halogenated series, a reversible reduction associated with the imine; peak positions and reversibility trends are consistent with halogen electronic effects and DFT-based MEP/LHS descriptors. Antimicrobial testing showed that SB-5 was selectively potent against Gram-positive aerobes, with low-to-mid micromolar MICs across the panel. Among anaerobes, activity was more substantial: Clostridioides difficile was inhibited at 0.1 µM, and SB-3/SB-5 reduced its sporulation at sub-MICs, while Blautia coccoides was highly susceptible (MIC 0.01 µM). No activity was detected against Gram-negative bacteria at the tested concentrations. In the fungal assay, Botrytis cinerea displayed only a transient fungistatic response without complete growth inhibition. In mammalian cells (HeLa), the compounds displayed clear concentration-dependent behavior. Overall, halogenation, particularly iodination, emerges as a powerful tool to couple redox tuning with selective Gram-positive activity and a favorable cellular tolerance window, nominating SB-5 as a promising scaffold for further antimicrobial optimization. Full article

We report the first green and diastereoselective synthesis of novel thiophene bioisosteres designed to mimic the privileged pyrrolo[3,2-c]quinoline core of martinelline alkaloids. The key step features an intramolecular 1,3-dipolar cycloaddition of in situ generated non-stabilized azomethine ylides from sarcosine, which proceeds with excellent yield and diastereoselectivity. This sustainable protocol, leveraging ultrasonic irradiation, recyclable hydrotalcite catalysts, and the green solvent cyclopentyl methyl ether (CPME), efficiently constructs the complex tricyclic framework. The structure and stereochemistry of the novel bioisostere were unambiguously confirmed by X-ray crystallography. This method offers a valuable, eco-friendly approach for diversifying natural product-inspired libraries in medicinal chemistry. Full article

Liposomal systems are advanced carriers of active substances which, thanks to their ability to encapsulate these substances, significantly improve their pharmacokinetics, bioavailability, and selectivity. This article presents the results of spectroscopic studies for a selected compound from the 1,3,4-thiadiazole group, namely 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol (NTBD, see below in the text), in selected liposomal systems formed from the phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Detailed spectroscopic analyses were carried out using electronic absorption and fluorescence spectroscopy; resonance light scattering (RLS) spectra measurements; dynamic light scattering (DLS); as well as time-resolved methods—fluorescence lifetime measurements using the TCSPC technique. Subsequently, based on the interpretation of spectra obtained by FTIR infrared spectroscopy, the preliminary molecular organization of the above-mentioned compounds within lipid multilayers was determined. It was found that NTBD preferentially occupies the region of polar lipid headgroups in the lipid multilayer, although it also noticeably interacts with the hydrocarbon chains of the lipids. Furthermore, X-ray diffraction (XRD) techniques were used to study the effect of NTBD on the molecular organization of DPPC lipid multilayers. Monomeric structures and aggregated forms of the above-mentioned 1,3,4-thiadiazole analogue were characterized using X-ray crystallography. Interesting dual fluorescence effects observed in steady-state fluorescence measurements were linked to the excited-state intramolecular proton transfer (ESIPT) effect (based on our earlier studies), which, in the obtained biophysical systems—liposomal systems with strong hydrophobicity—is greatly enhanced by aggregation-induced emission (AIE) effects. In summary, the research presented in this study, concerning the novel 1,3,4-thiadiazole derivative NTBD, is highly relevant to drug delivery systems, such as various model liposomal systems, as it demonstrates that depending on the concentration of the selected fluorophore, different forms may be present, allowing for appropriate modulation of its biological activity. Full article

Low-temperature superconductivity has been known since 1957 to be described by BCS theory for effective single-band metals controlled by the density of states at the Fermi level, very far from band edges, the electron–phonon coupling constant l, and the energy of the boson in the pairing interaction w₀, but BCS has failed to predict high-temperature superconductivity in different materials above about 23 K. High-temperature superconductivity above 35 K, since 1986, has been a matter of materials science, where manipulating the lattice complexity of high-temperature superconducting ceramic oxides (HTSCs) has driven materials scientists to grow new HTSC quantum materials up to 138 K in HgBa₂Ca₂Cu₃O₈ (Hg1223) at ambient pressure and near room temperature in pressurized hydrides. This perspective covers the major results of materials scientists over the last 39 years in terms of investigating the role of lattice inhomogeneity detected in these new quantum complex materials. We highlight the nanoscale heterogeneity in these complex materials and elucidate their special role played in the physics of HTSCs. Especially, it is highlighted that the geometry of lattice and charge complex heterogeneity at the nanoscale is essential and intrinsic in the mechanism of rising quantum coherence at high temperatures. Full article

There are 25 crystal structures of Lipase B from Candida antarctica (CalB) that have been previously reported. In this study, we report the first CalB crystal structure that shows the assumed pro-peptide region at the N-terminus (Ala19–Arg25). This 1.45 Å structure shows that this segment of seven amino acids is an extension of the N-terminal loop and that it does not interact with or effect conformational changes in the flexible lid domain, which covers the active site of the enzyme. As such, this region is unlikely to be a classical pro-peptide. Full article

Amorphous hydrogenated germanium–carbon alloys (Ge_1−xC_x:H) were synthesized by X-ray-activated Chemical Vapor Deposition and investigated to evaluate the effects of annealing on their structure, composition, and properties given the limited information available on their behavior at high temperatures. Thermogravimetric and elemental analyses showed that the materials are stable up to 573 K; above this temperature, the carbon and hydrogen content progressively decrease, favoring structural reorganization. XRPD and Raman analyses demonstrate that the as-deposited films are fully amorphous, while annealing promotes the progressive formation of crystalline Ge. This crystallization occurs heterogeneously through the nucleation of small “islands” embedded within the sample matrix. Optical measurements reveal a narrowing of the band gap with increasing annealing temperature and time. The weak contribution of sp²-carbon observed in some Raman spectra indicates that band gap reduction is mainly governed by the overall composition and the variation of germanium hydrogen bonding configuration, rather than by graphitization. The study also notes that the parameter B^1/2 does not follow a regular trend due to the complex nature of the material’s microstructural evolution during annealing. These results provide a comprehensive picture of the annealing-driven transformations in Ge–C:H alloys relevant for the design of thermally stable optoelectronic materials. Full article

Proteases play key roles in many industrial processes and account for the majority of global enzyme sales. Geobacillus isolates from extreme environments such as marine hydrothermal vents are capable of producing high yields of proteases with thermophilic properties. Many proteases produced by Geobacillus species have been extensively studied, some of which have been purified and characterized. In addition, the high thermal stability largely depends on structural stability. Based on X-ray crystallography, several factors have been found to affect the structural stability of the thermostable proteases of Geobacillus. Moreover, the thermostable proteases of Geobacillus have a wide range of biotechnological applications, such as in detergent, food, bioremediation, leather-processing and textile industries. Therefore, this review focusses on the thermostable proteases of Geobacillus, including their characteristics, structural stability mechanisms and biotechnological applications. It will help the development of utilizing thermostable protease resources and enhancing their suitability for use in various industrial applications. Full article

Category Theory provides us with a clear notion of what is an internal algebraic structure. This will allow us to focus our attention on a certain kind of relationship between context and structure; namely on categories $\mathbb{E}$ (context) in which, on any object X, there is, at most, one algebraic structure of some type S. Full article

A new polymorph modification of SrB₂O₄ was obtained from melt containing Sr₂CO₃, H₃BO₃ and CuCl₂·2H₂O with a molar ratio of 2:2:1. The growth was carried out by cooling the melt from 1180 to 860 °C. The obtained material looks like a green bulk mass at the edges, of which grew transparent single crystals of SrB₂O₄ (approximately 0.1 × 0.2 × 0.1 mm in size). The crystals were studied by scanning electron microscopy, single crystal, powder X-ray diffraction, DTA/TG and FTIR spectroscopy. The single crystal structure data of SrB₂O₄ shows orthorhombic Pna2₁ symmetry. The structure is built up of linked BO₄ and BO₃ units and the charge is compensated by strontium cations. Full article

Recently, 3-hydroxy-4-pyridinones have been extensively studied as chelating bidentate agents of metal ions for various biomedical applications. This study reports the structural characterization and density functional theory (DFT) analysis of centrosymmetric calcium complex based on 4-(3-hydroxy-2-methyl-4-oxopyridin-1(4H)-yl) acetic acid (1). The structure of complex 1 was determined by X-ray crystallography. The 3-hydroxy-4-pyridinone ligand in the studied complex is bound to the calcium ion in the desired monodentate, non-bridging manner. The calcium ion has a coordination number of six and adopts a distorted octahedral geometry. Analyzed geometric characteristics corresponding to hydrogen bonds in the crystal. The theoretical study of intra- and intermolecular interactions utilized DFT with the PBE0-D3/def2-TZVP (Gaussian Inc., Wallingford, CT, USA) level of theory. The charge redistribution in the ligand was studied in comparison with the free acid molecule. Full article

The National Laboratories in Frascati (LNF INFN) were conceived and created by a group of collaborators of Enrico Fermi, including Edoardo Amaldi, Gilberto Bernardini, and Enrico Persico, after World War II, with the goal of hosting a 1 GeV electron synchrotron for nuclear physics [...] Full article