Search Results (699)

Direct comparisons of MnO₂ polymorphs in synthetic benzylic oxidation remain limited, particularly regarding the combined effects of crystallinity, morphology, surface area, and surface-associated water. In this study, α-, β-, and γ-MnO₂ were prepared by hydrothermal methods and benchmarked against nano-MnO₂ for the oxidation of diphenylmethane to benzophenone. XRD, TGA, FTIR, BET, and SEM analyses confirmed phase-defined crystalline polymorphs, distinct wire- or rod-like morphologies, and marked differences in surface area and water retention. Nano-MnO₂ exhibited a porous, poorly crystalline nanoscale structure with the highest surface area and delivered the greatest oxidation efficiency under aerobic, atmospheric, and anaerobic conditions. Among the crystalline phases, α-MnO₂ showed the highest activity despite its lower BET surface area than β-MnO₂, indicating that surface-associated water is more influential than surface area alone. The loss of activity after drying at 120 °C, prolonged storage, or reuse further supports the critical role of labile surface-bound water. Overall, this work establishes a structure–morphology–water–reactivity relationship for MnO₂-mediated arylmethylene oxidation and identifies water-rich nano-MnO₂ as the most effective material for converting benzylic substrates to ketones. Full article

The production of refined ferrochrome is accompanied by the formation of self-disintegrating slags caused by the β→γ-Ca₂SiO₄ polymorphic transformation during cooling, resulting in environmental and technological problems. This study aimed to develop and validate a technology for long-term stabilization of refined ferrochrome slags using remelted and desulfurized borate ore (RDBO) from the Inder deposit as an alternative to colemanite. Thermodynamic modeling, X-ray diffraction (XRD), scanning electron microscopy (SEM), and pilot-industrial trials were conducted to evaluate phase transformations, microstructure formation, and slag stability. The results showed that the addition of boron oxide promoted the formation of stable borate phases, primarily CaB₄O₇, and reduced the content of unstable Ca₂SiO₄ phases. Autoclave testing under saturated steam conditions (400 kPa, ~180 °C, 24 h) demonstrated complete preservation of structural integrity in all RDBO-stabilized samples, with an average mass loss of 0.19 ± 0.01%, whereas colemanite-stabilized slags exhibited cracking and partial disintegration. The stabilization effect was achieved at a B₂O₃ content of 0.17–0.47 wt.% without boron contamination of ferrochrome. The proposed technology ensures long-term slag stability and enables the utilization of stabilized slag as a technogenic material for road construction. Full article

Uridine diphosphate glucuronosyltransferase 2B (UGT2B) enzymes constitute a critical subgroup of phase II metabolizing enzymes that modulate the clearance of steroid hormones, carcinogens, and numerous anticancer agents, thereby influencing cancer susceptibility, progression, and therapeutic outcomes. This review provides a comprehensive synthesis of the genetic, regulatory, and functional roles of UGT2B family members, particularly UGT2B4, UGT2B7, UGT2B10, UGT2B15, UGT2B17, and UGT2B28, in oncogenesis and cancer treatment. We summarize evidence from molecular, epidemiological, pharmacogenetic, and clinical studies demonstrating how UGT2B expression patterns, polymorphisms, copy number variations, epigenetic regulation, and microRNA-mediated control shape intratumoral hormone homeostasis, carcinogen detoxification, and drug resistance across multiple malignancies, including prostate, breast, lung, colorectal, hematological, and hormone-dependent cancers. UGT2B enzymes metabolize several widely used anticancer drugs and active metabolites, thereby affecting pharmacokinetics, efficacy, and toxicity. Understanding the context-specific roles of UGT2B family members offers a compelling opportunity for therapeutic exploitation. In particular, rational combination strategies incorporating UGT2B inhibitors or modulators alongside standard anticancer agents may enhance drug effectiveness without increasing dosage, while simultaneously enabling the dose reduction of the partner agent to mitigate dose-dependent toxicities. Such approaches are especially relevant for therapies with narrow therapeutic indices. Overall, this review highlights UGT2B enzymes as multifunctional determinants of cancer risk and treatment response and underscores their promise as biomarkers and actionable targets for precision oncology and optimized combination regimens. Full article

Wittichenite (Cu₃BiS₃) was synthesized by mechanical alloying (MA) followed by hot pressing (HP), and its phase evolution, thermal stability, charge transport behavior, and thermoelectric performance were systematically examined. X-ray diffraction analysis of the MA powders revealed broadened diffraction peaks, indicating reduced crystallinity and refined crystallite size. After HP consolidation, a well-defined single-phase orthorhombic wittichenite structure was obtained. These results demonstrate that the mechanically induced solid-state synthesis was effectively initiated during MA and subsequently completed through crystallization, defect relaxation, and densification during HP. The MA–HP processed specimens exhibited high relative densities of 94–98% of the theoretical value and a homogeneous microstructure without detectable compositional segregation or grain-boundary enrichment, confirming the formation of a structurally and chemically stable single-phase bulk material. Thermal analysis identified a reversible polymorphic phase transition from P2₁2₁2₁ to Pnma at low temperature, followed by structural relaxation and the onset of partial decomposition at higher temperatures, indicating that Cu₃BiS₃ retains structural integrity below 700 K, which defines the relevant operating window for thermoelectric evaluation. The samples exhibited p-type semiconducting behavior, with electrical conductivity increasing with temperature due to thermally activated hole transport and showing an additional enhancement across the structural transition region. The Seebeck coefficient remained positive over the entire temperature range and decreased gradually with increasing temperature, consistent with semiconductor transport characteristics. The thermal conductivity remained low at 0.30–0.38 W·m⁻¹·K⁻¹, with a negligible electronic contribution, confirming that heat transport is dominated by lattice phonon scattering. As a result of the combined increase in electrical conductivity and intrinsically low thermal conductivity, the dimensionless figure of merit (ZT) increased continuously with temperature and reached 0.17 at 673 K. These results demonstrate that the MA–HP route provides an effective and scalable strategy for producing phase-pure Cu₃BiS₃ with controlled microstructure and reproducible thermoelectric performance. Full article

In this work, we present a theoretical study of InPO₄ under pressure. Total-energy calculations based on density functional theory were performed to explore the crystal structure of InPO₄ in light of the recent X-ray diffraction characterization of this compound under pressure. A phase coexistence was observed above 10 GPa, involving the ambient-pressure CrVO₄-type structure and the high-pressure scheelite and zircon phases. Therefore, the previously performed analysis of InPO₄ behavior under pressure is extended by simulating X-ray spectra and interplanar distances for the three polymorphs. In addition, the elastic behavior of the three phases is analyzed to assess the elastic stability of InPO₄ under pressure and to compute the mechanical properties and elastic anisotropy. Our findings significantly extend previous experimental results on the compressibility of InPO₄, which were limited to the ambient-pressure phase. Moreover, our results unambiguously reveal a marked difference in the elastic properties of the scheelite and zircon phases under pressure, showing that the zircon phase is elastically unstable at high pressures. This suggests that the reported coexistence of phases may result from kinetic barriers or from non-hydrostatic conditions within the diamond anvil cell caused by the pressure-transmitting medium. Full article

Background: Glucuronidation is a major phase II biotransformation reaction responsible for the inactivation and elimination of endogenous compounds and pharmaceuticals. This process is catalyzed by enzymes belonging to the UDP-glucuronosyltransferase (UGT) family, among which UGT1A1 is the most extensively studied. UGT1A1 plays a critical role in the metabolism of numerous drugs and is essential for bilirubin glucuronidation. Due to this specific function, it has significant clinical relevance, as impaired enzyme activity resulting from genetic polymorphisms or mutations can lead to the accumulation of unconjugated bilirubin in the bloodstream. This study aimed to evaluate the association between the UGT1A1*28 allele and the gene expression and protein levels in human liver tissue, in relation to different liver diseases. Methods: Liver tissues were obtained from patients with various liver pathologies and the control group consisted of tissues showing no pathological symptoms. A total of 143 patients were included in the study. Pyrosequencing was used to analyze PCR products for the UGT1A1*28 polymorphism (variable number of TA repeats in the TATA sequence of the promoter). Results: In both the control and study groups, UGT1A1 gene expression at the mRNA level and protein concentration in liver tissue decreased with the increasing number of UGT1A1*28 alleles. The association between UGT1A1 genotype and mRNA/protein content was most pronounced in HCV and AIH, and slightly weaker in the ALK and PBC groups. The significant association between UGT1A1*28 allele and bilirubin concentration was observed in control group but not in liver pathology. Conclusions: The UGT1A1*28 polymorphism is associated with reduced hepatic mRNA and protein abundance in patients with liver disease. However, the significance of this observation for the metabolism of the enzyme substrates should be further investigated. Full article

Since the first successful synthesis of borophene in 2015, this atomically thin boron allotrope has attracted extensive attention due to its polymorphic structures, metallic conductivity, and outstanding mechanical flexibility. As a new member of the two-dimensional (2D) materials family, borophene exhibits a unique triangular lattice with tunable hexagonal vacancies, leading to rich structural diversity and anisotropic physical properties. Recent breakthroughs in synthesis—particularly molecular beam epitaxy (MBE), chemical vapor deposition (CVD), and solvothermal-assisted liquid-phase exfoliation (S-LPE)—have significantly expanded the accessible structural phases and improved control over film quality and stability. Meanwhile, borophene’s distinctive combination of structural and electronic characteristics has enabled its rapid development in both energy and biomedical applications. In energy storage, borophene serves as a promising anode material for lithium/sodium-ion batteries and a lightweight medium for hydrogen storage and supercapacitors, owing to its metallic conductivity, high surface charge density, and large adsorption capacity. In biomedicine, borophene-based nanoplatforms exhibit excellent photothermal conversion efficiency, enabling multifunctional roles in cancer diagnosis and therapy. Despite these advances, several challenges—such as environmental instability, oxidation susceptibility, and limited scalable synthesis—continue to restrict practical implementation. Future progress will depend on chemical functionalization, surface passivation, and machine-learning-assisted materials design to achieve oxidation-resistant, large-area, and biocompatible borophene derivatives. This review summarizes recent advances in borophene synthesis, structural engineering, and multifunctional applications, while outlining key scientific challenges and future opportunities for the realization of borophene-based materials in next-generation energy and biomedical systems. Full article

The genomic landscape of myelodysplastic syndromes/neoplasms (MDS), a heterogeneous group of myeloid malignancies defined by bone marrow cell dysplasia with ineffective hematopoiesis, includes somatic and, less frequently, germline mutations in hematopoietic stem and progenitor cells, along with chromosomal abnormalities. The latest World Health Organization 2022 classification of myeloid neoplasms, as well as stratification in lower-risk (LR) and higher-risk (HR) MDS using either the Revised International Prognostic Scoring System (IPSS-R) or the Molecular International Prognostic Scoring System (IPSS-M), guide prognostic assessment and risk-adjusted therapy. We report the case of an 81-year-old patient diagnosed with LR-MDS according to IPSS-R that exhibited direct progression to acute myeloid leukemia. The retrospective analysis of paired DNA samples from MDS and leukemic phases, obtained four months apart, using both targeted next-generation sequencing and single nucleotide polymorphism array, indicated swift alterations in the genomic profile, being suggested that the leukemic clone emerged from the clone harboring homozygous TET2 and heterozygous SRSF2 variants that acquired RUNX1, BCOR, BCORL1 likely pathogenic mutations and trisomy 13. By employing IPSS-M for prognostic evaluation at the MDS phase, the patient would have been assigned to the HR-MDS category with a possible benefit from hypomethylating agent therapy. Risk stratification is of pivotal importance in a patient-centered approach to MDS treatment being significantly improved by incorporating the molecular genetic findings. Full article

Heat transport properties of serpentine minerals are important to the thermal state of subduction zones, but available data contain systematic errors from contact losses, radiative gains, deformation with pressure (P), and/or modelling short-comings. Here, laser flash analysis (LFA) provides thermal diffusivity (D) within ±3% as a function of temperature (T) of perpendicularly oriented, nearly pure Mg₃Si₂O₅(OH)₄ polymorphs, Al-rich lizardite with minor brucite, three serpentinites, plus chrysotile and lizardite near Ni₃Si₂O₅(OH)₄. Visible spectra show that Fe is mostly ferric and Cr³⁺ occasionally occupies tetrahedral sites. The proposed coupled substitution of Al³⁺ + OH⁻ replacing Si⁴⁺ + O²⁻ accounts for extra OH⁻ peaks in infrared spectra. Rietveld refinements and infrared spectra reveal that serpentine dehydration in LFA runs begins near 800 K. Thermal conductivity (K) vs. T is calculated within ~±5% from D, available heat capacity data, and ambient density. For antigorite, D and K are strongly anisotropic whereas chrysotile has extreme differences, but lizardite is nearly isotropic. A thermodynamic identity provides ∂(lnK)/∂P = 11 ± 1% Gpa⁻¹ for soft serpentine, double that of hard olivine. Lizardite becomes more thermally conductive than olivine near the 1 bar decomposition temperature, which increases with P. Through feedback, and because released H₂O vapor carries heat upwards, P,T conditions in serpentinized slabs follow the decomposition phase boundary during subduction. Full article

The stability of the competing orthorhombic Pnma and monoclinic P2₁/c phases of Praseodymium pentaphosphate (PrP₅O₁₄) have been studied using density functional theory (DFT). At 0 K, the Pnma structure is found to be preferred over the P2₁/c one with the enthalpy change with pressure of both phases highlighting a shift in phase preference from Pnma to P2₁/c at ∼2.5 GPa. Independently of the predicted high-pressure structural phase transition at 0 K, our computed elastic properties and phonon dispersion bands as a function of pressure indicate a phonon instability at ∼4.5 GPa due to the appearance of imaginary frequencies, followed by a dynamical instability at 8.5 GPa due to the violation of the Born criteria on the Pnma structure of PrP₅O₁₄. These results eliminate the orthorhombic structure as a possible high-pressure candidate for the monoclinic P2₁/c polymorph. Furthermore, the relative stability of the orthorhombic and monoclinic polymorphs has been evaluated at ambient pressure and as a function of temperature by means of vibrational free-energy calculations. The results indicate a free-energy crossing at 42 K, with the Pnma phase being energetically favored from 0 K to 42 K, after which the P2₁/c phase becomes preferred. These results demonstrate why PrP₅O₁₄ can only be obtained at ambient pressure in the monoclicnic P2₁/c polymorph, different to other rare earth pentaphosphates. Full article

Indigenous sheep breeds represent valuable reservoirs of genetic diversity shaped by long-term adaptation to local environments and management systems. Greek autochthonous sheep breeds remain underrepresented in genomic and functional studies. The objective of this study was to characterize and compare coding sequence variation in three indigenous Greek sheep breeds—Lesvos (LES), Serres (SER), and Thrace (THR)—and to identify shared and breed-associated functional patterns. The study was designed using a two-stage approach, comprising a discovery (exploratory) phase and a validation phase. In the discovery phase, whole genome sequencing data (one animal per breed; total n = 3; mean sequencing depth ~36.9×) were analyzed to identify protein-altering exonic variants, focusing on missense single-nucleotide polymorphisms (SNPs) and exonic insertions/deletions (indels). Variants were examined at breed-specific and comparative levels, followed by functional enrichment analyses using Gene Ontology (GO) and KEGG pathways. Normalized variant density metrics identified genes with elevated polymorphism levels. In the validation phase, a subset of prioritized missense SNPs was genotyped in an independent cohort of 54 animals (18 per breed) using MassARRAY genotyping. Genes harboring prioritized missense SNPs showed a conserved enrichment profile across breeds, dominated by genome maintenance, DNA repair, cytoskeletal organization, and core regulatory functions. Distinct breed-associated patterns were also observed. LES showed enrichment in metabolic, biosynthetic, and sensory-related processes, SER in regulatory and signaling functions, and THR in cytoskeletal, extracellular matrix, and organelle-associated pathways. Polymorphism density analyses highlighted highly variable genes across breeds, including olfactory receptor (OR) gene families, keratin-associated protein genes (KRTAPs), and loci involved in immune and regulatory functions (e.g., PRKDC, CDH15). The validation phase confirmed the expected allele frequency patterns for most prioritized SNPs, supporting the robustness of the approach. This study identifies functionally relevant coding variation across Greek indigenous sheep breeds, revealing conserved genomic patterns and breed-associated signatures linked to metabolic, structural, and regulatory processes. Full article

An experimental investigation of the Cu-As-Sb ternary system in the Cu-rich region led to the identification of a new intermetallic phase, Cu₅(As,Sb)₂. The compound crystallizes in the orthorhombic Mg₅Ga₂-type structure (oI28, Ibam), analogous to the binary parent phase Cu₅As₂, with lattice parameters a = 5.968–5.977(1) Å, b = 11.550–11.565(3) Å, c = 5.530–5.573(3) Å. Similar to the parent Cu₅As₂ phase, the ternary compound forms with slight Cu under stoichiometry and exhibits a limited compositional range, with no continuous solid solubility between the binary and ternary phases. The phase formation, compositional stability, and decomposition behavior were systematically studied using a combination of powder and single-crystal X-ray diffraction (XRD, including Rietveld refinement), metallographic analysis with optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy (LOM, SEM-EDXS), electron backscatter diffraction (EBSD) and thermal analysis (DTA, DSC). The results reveal that Cu₅(As,Sb)₂ is a high-temperature phase forming peritectically at 650–635 °C and stable only within a limited temperature interval. No continuous solid solubility exists between the ternary compound and the parent binary phase Cu₅As₂. Its formation occurs in strong competition with that of two other close neighboring solid-solution compounds, [Cu_3−x(As_1−ySb_y) (Cu₃P-type; hP24, P6₃cm) and Cu_3−x(As,Sb) (Cu₉TeSb₂-type; cP32, Pm−3n)], reflecting a complex interplay between composition, solubility ranges and thermal history. No evidence for the existence of high-temperature (HT) and low-temperature (LT) polymorphic phases was found for either the binary compound Cu₅As₂ or the ternary compound Cu₅(As,Sb)₂. Electrical resistivity measurements on a quenched sample indicate metallic behavior. These findings provide new insight into phase stability and structure–property relationships in Cu-As-Sb alloys and contribute to the understanding of competing intermetallic phases in this system. Full article

Organic light-emitting diode (OLED)-based devices continue to grow rapidly in popularity. This work presents a comprehensive thermodynamic study of four nitrogen-containing organic semiconductors: 1,3-bis(9H-carbazol-9-yl)benzene (mCP), 1,3,5-tri(9H-carbazol-9-yl)benzene (TCB), 1,3,5-tris(diphenylamino)benzene (TDAB), and 1,3,5-tris[(3-methylphenyl)phenylamino]benzene (m-MTDAB). A self-consistent set of phase-change thermodynamic parameters in a wide temperature range was obtained using several independent experimental and computational techniques. Vapor pressure measurements above the liquid and crystalline phases of the compounds under study were carried out using the thermogravimetry–fast scanning calorimetry method. Based on the temperature dependence of the measured vapor pressures, vaporization and sublimation enthalpies were derived. Differential scanning calorimetry was employed to determine the heat capacities of the condensed phases and the melting parameters of the studied compounds, as well as to investigate the polymorphism of TCB. Solution calorimetry was used to determine the fusion enthalpies of the compounds at 298.15 K. The obtained values were additionally compared with the literature data and calculated estimates. The results of this study may be used to predict properties for compounds with similar molecular structures. Full article

This study used calcium hydroxide (CH) to simulate the alkaline environment of cement and to activate lithium slag (LS), aiming to reveal the mechanism of LS in cement. The early-age hydration of LS blended with 10 wt.% CH was monitored via isothermal calorimetry (ICC) at ambient temperature, followed by a comparative analysis of phase assemblage, microstructure, and macroscopic properties under standard and steam curing conditions. The results show that LS exhibits superior early reactivity within the first 9 h, which is attributed to abundant ettringite formation. Two distinct exothermic peaks were identified during LS-CH hydration, corresponding to (i) ettringite formation accompanied by LS dissolution and C–S–H precipitation, and (ii) CaCO₃ crystallization and renewed ettringite formation. The hydrated paste consists of abundant AFt, CaCO₃ polymorphs, unreacted LS particles, and a small amount of C–S–H gel with a low Ca/Si ratio and incorporating Al and S. This unique phase assemblage results in a coarser pore structure and lower specific surface area compared with conventional cement paste. Nevertheless, the system achieves a relatively high 28-day compressive strength, highlighting the promise of LS-CH blends as sustainable cementitious materials. Full article

Background: Amorphous drug formulations are commonly used to improve the solubility and bioavailability of poorly soluble molecular pharmaceuticals, yet less is known about their molecular conformations and local bonding interactions than their crystalline phases. Methods: High-energy X-ray diffraction structure factor measurements have been made on liquid and glassy nifedipine (NIF), felodipine (FEL), NIF 1:3 polyvinylpyrrolidone (PVP), and FEL 1:3 PVP wt.% mixtures. The corresponding X-ray pair distribution functions have been interpreted using empirical potential structure refinement using different models and density functional theory conformer calculations. Results: In both NIF and FEL, the NH···O inter-molecular hydrogen bonds between the pyridyl nitrogen and ester carbonyls are found to be considerably weaker than those observed in the crystalline polymorphs. For nifedipine, it is proposed that either inter-molecular NH…ON nitro bonds are present and/or a fraction (<20%) of conformational changes, with the aryl ring flipped, occur in the liquid state. For felodipine, the models indicate significant disorder associated with the methyl and ethyl side chains in the liquid state, with the main peak intensity at 3.0 Å arising from intra-molecular Cl-Cl atom pairs. When nifedipine molecules are incorporated into PVP, our models show they possess stronger NH···O bonds to the PVP polymer than felodipine molecules, which have stronger affinity for bonding to the polymer than to other felodipine molecules. Conclusions: The amorphous forms of both NIF and FEL show much weaker hydrogen bonding than found in their crystalline phases. Liquid NIF also exhibits configurations which are not observed in the crystal phases. Full article