Search Results (12)

Infection urinary stones account for approximately 10–15% of all urinary stones worldwide, with a rising incidence observed in recent decades, particularly in countries with a high Socio-Demographic Index (SDI). This trend has been partially attributed to dietary changes, including increased consumption of processed foods. Heavy metals belong to a group of substances, the source of which can be both food and the human environment. Among many heavy metals, in this study, we focus on copper and investigate its influence on the nucleation and growth of struvite crystals, the primary component of infection urinary stones. Experiments were conducted in artificial urine, both in the presence and absence of Proteus mirabilis, a urease-producing bacterium commonly associated with infection urinary stones. In a bacteria-free system, bacterial urease activity was mimicked by the addition of aqueous ammonia solution. Our results demonstrate that the presence of copper in artificial urine induces a slight shift in the struvite crystallization toward lower pH values, indicating that crystal formation initiates earlier compared to a control test. Additionally, the amount of precipitated struvite increases modestly in the presence of copper. Struvite crystals formed in copper-containing artificial urine are larger and exhibit altered habit and morphology. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses confirm that copper does not incorporate into either the bulk or surface structure of the struvite crystals. X-ray diffraction (XRD) data show that struvite remains the sole crystalline phase, consistent with the control samples. Microbiological assays reveal that copper, at the concentrations tested, does not affect the viability of P. mirabilis, indicating an absence of bacteriostatic or bactericidal effects. To elucidate the physicochemical mechanisms underlying copper’s influence on nucleation and growth of struvite, speciation analysis of chemical complexes was performed. This revealed the formation of various copper complexes in artificial urine, including Cu(OH)⁺, CuCit⁻, CuC₂O₄, Cu(OH)₂, CuHPO₄, Cu(NH₃)²⁺, Cu(NH₃)₂²⁺, and Cu(NH₃)₃²⁺. These chemical complexes modulate the equilibrium and formation of complexes with Mg²⁺ and PO₄³⁻ (e.g., MgHCit, MgCit⁻, MgOH⁺, MgC₂O₄, MgSO₄, MgHPO₄), contributing to the observed shift in struvite crystallization to lower pH values. Full article

Crystallization in microgravity has measurable benefits, from molecules as simple as sodium chloride to elaborate protein complexes. However, small organic molecules have not been reported. The small organic molecules glycine, famoxadone, carbamazepine, and 5-methyl-2-((2-nitrophenyl)amino)thiophene-3-carbonitrile (ROY) were crystallized on Earth under microgravity conditions. When comparing these different gravity crystallization conditions, we found the formation of different polymorphs and/or habits for glycine, carbamazepine, and ROY. The crystallization of famoxadone occurred more slowly in microgravity. The differences in size, appearance, and, in the case of ROY, color, are detailed in this report. Full article

In this study, a rare 3.49-carat yellow diamond was analyzed to reconstruct the geological processes that led to its distinctive form. The diamond exhibits growth and dissolution features, indicating a complex history. To preserve the sample’s integrity, non-destructive analytical techniques—including VIS, UV–Vis–NIR, and IR spectroscopy—were employed. The yellow coloration of the diamond is attributed to the presence of N3 and N2 defects. Additionally, other defects such as N₃VH⁰ centers and platelets were detected; however, the latter do not contribute to the coloration. The observations of the etch pits and surface microreliefs suggest that the diamond underwent size reduction due to dissolution events, which also altered its crystal habit over time. The diamond’s initial mixed-habit morphology evolved into a more complex one through a series of growth and dissolution processes that began during mantle storage. Furthermore, the presence of brown surface stains indicates radiation damage, likely acquired during its residence in alluvial deposits at the Earth’s surface. Full article

Intentionally adding select ions such as Al³⁺ could be helpful in controlling the crystal habit of KDP crystal for high yield of optics. The study of how Al³⁺ ions affect crystal quality can provide a basis for selecting an appropriate doping level without negatively affecting the optical properties of crystals. Here, the influence of Al³⁺ ions on the crystal structure and properties of KDP crystals have been investigated by using first-principles calculations. Theoretical calculations show that Al³⁺ ions mainly replace K sites in KDP crystals and could complex with intrinsic V_H⁻ point defects to form Al_K²⁺ + 2V_H⁻ cluster defects. The linear absorption spectra indicate that the presence of Al³⁺ ions has minimal impact on the linear absorption of KDP crystals, aligning well with the experimental findings. And Al³⁺ ions could cause a slight shortening of the band gap of KDP crystals. However, these ions could bring significant deformations of O-H bonds. As the concentration of Al³⁺ ions increase, more O-H bonds linking to PO₄ groups are distorted in KDP crystals. As a result, the structural instability could be fast enhanced with increasing the defect concentration. Therefore, high concentrations of Al³⁺ ions could cause the instability of the crystal structure, which finally affects the laser-induced damage resistance of the KDP crystals. This manuscript contributes to a more comprehensive understanding of the physical mechanisms by which different impurity ions affect the optical properties of KDP crystals. Full article

Using cocrystals has emerged as a promising strategy to improve the physicochemical properties of active pharmaceutical ingredients (APIs) by forming a new crystalline phase from two or more components. Particle size and morphology control are key quality attributes for cocrystal medicinal products. The needle-shaped morphology is often considered high-risk and complex in the manufacture of solid dosage forms. Cocrystal particle engineering requires advanced methodologies to ensure high-purity cocrystals with improved solubility and bioavailability and with optimal crystal habit for industrial manufacturing. In this study, 3D-printed microfluidic chips were used to control the cocrystal habit and polymorphism of the sulfadimidine (SDM): 4-aminosalicylic acid (4ASA) cocrystal. The addition of PVP in the aqueous phase during mixing resulted in a high-purity cocrystal (with no traces of the individual components), while it also inhibited the growth of needle-shaped crystals. When mixtures were prepared at the macroscale, PVP was not able to control the crystal habit and impurities of individual mixture components remained, indicating that the microfluidic device allowed for a more homogenous and rapid mixing process controlled by the flow rate and the high surface-to-volume ratios of the microchannels. Continuous manufacturing of SDM:4ASA cocrystals coated on beads was successfully implemented when the microfluidic chip was connected in line to a fluidized bed, allowing cocrystal formulation generation by mixing, coating, and drying in a single step. Full article

A diamond plate cut out of a transparent, colorless octahedral diamond crystal of gem quality, with a small chromite inclusion in the core, sampled from the XXIII CPSU Congress kimberlite (Yakutia, Mirny kimberlite field, vicinities of Mirny city), has been studied by several combined methods: absorption spectroscopy at different wavelengths (UV-visible, near- and mid-IR); photoluminescence, cathodoluminescence, and Raman spectroscopy (local version) and lattice strain mapping; birefringence in cross-polarized light; and etching. The diamond plate demonstrates a complex growth history consisting of four stages: nucleation and growth to an octahedron → habit change to a cuboid → habit change to octahedron-1 → habit change to octahedron-2. The growth history of the diamond records changes in the crystallization conditions at each stage. The revealed heterogeneity of the crystal structure is associated with the distribution and speciation of nitrogen defects. The results of this study have implications for the information value of different techniques as to the diamond structure defects, as well as for the as yet poorly known evolution of the subcontinental lithospheric mantle in the Siberian craton, recorded in the multistage growth of the diamond crystal. At the time of writing, reconstructing the conditions for each stage is difficult. Meanwhile, finding ways for such reconstruction is indispensable for a better understanding of diamond genesis, and details of the lithosphere history. Full article

Comminution of BCS II APIs below the 1 μm threshold followed by solidification of the obtained nanosuspensions improves their dissolution properties. The breakage process reveals new crystal faces, thus creating altered crystal habits of improved wettability, facilitated by the adsorption of stabilizing polymers. However, process-induced transformations remain unpredictable, mirroring the current limitations of our atomistic level of understanding. Moreover, conventional equations of estimating dissolution, such as Noyes–Whitney and Nernst–Brunner, are not suitable to quantify the solubility enhancement due to the nanoparticle formation; hence, neither the complex stabilizer contribution nor the adsorption influence on the interfacial tension occurring between the water and APIs is accounted for. For such ternary mixtures, no numeric method exists to correlate the mechanical properties with the interfacial energy, capable of informing the key process parameters and the thermodynamic stability assessment of nanosuspensions. In this work, an elastic tensor analysis was performed to quantify the API stability during process implementation. Moreover, a novel thermodynamic model, described by the stabilizer-coated nanoparticle Gibbs energy anisotropic minimization, was structured to predict the material’s system solubility quantified by the application of PC-SAFT modeling. Comprehensively merging elastic tensor and PC-SAFT analysis into the systems-based Pharma 4.0 algorithm provided a validated, multi-level, built-in method capable of predicting the critical material quality attributes and corresponding key process parameters. Full article

Electromagnetic wave scattering by ice particles is commonly modeled by defining representative habits, including droxtals, columns, plates, and aggregates, although actual particles in the atmosphere can be even much more complex. In this study, we examined a superspheroidal approximation method for modeling electromagnetic wave scattering by ice crystals. Superspheroid can be associated with a shape index (SI) defined by the particle volume and average projected area. Corresponding to realistic ice crystals, suitable superspheroid models with the same SI (that means, identical volume and average projected area) and aspect ratio can be identified as surrogates for optical property calculations. We systematically compared the optical properties of ice crystals and superspheroids at 33 microwave bands in the range of 3–640 GHz and at three representative visible or infrared wavelengths (0.66, 2.13, and 11 μm). It was found that the single-scattering properties of compact ice crystal habits and their superspheroidal model particles were quite close. For an aggregate with sparse distribution of elements, a superspheroid model produces relatively large errors because the aspect ratio may not be sufficient to describe a particle shape. However, the optical similarity of a superspheroid and an aggregate is still encouraging. Full article

Lath martensite is a complex hierarchical compound structure that forms during rapid cooling of carbon steels from the austenitic phase. At the smallest, i.e., ‘single crystal’ scale, individual, elongated domains, form the elemental microstructural building blocks: the name-giving laths. Several laths of nearly identical crystallographic orientation are grouped together to blocks, in which–depending on the exact material characteristics–clearly distinguishable subblocks might be observed. Several blocks with the same habit plane together form a packet of which typically three to four together finally make up the former parent austenitic grain. Here, a fully parametrized approach is presented which converts an austenitic polycrystal representation into martensitic microstructures incorporating all these details. Two-dimensional (2D) and three-dimensional (3D) Representative Volume Elements (RVEs) are generated based on prior austenite microstructure reconstructed from a 2D experimental martensitic microstructure. The RVEs are used for high-resolution crystal plasticity simulations with a fast spectral method-based solver and a phenomenological constitutive description. The comparison of the results obtained from the 2D experimental microstructure and the 2D RVEs reveals a high quantitative agreement. The stress and strain distributions and their characteristics change significantly if 3D microstructures are used. Further simulations are conducted to systematically investigate the influence of microstructural parameters, such as lath aspect ratio, lath volume, subblock thickness, orientation scatter, and prior austenitic grain shape on the global and local mechanical behavior. These microstructural features happen to change the local mechanical behavior, whereas the average stress–strain response is not significantly altered. Correlations between the microstructure and the plastic behavior are established. Full article

An attempt to reveal the mechanisms of scale inhibition with the use of two different fluorescent-tagged antiscalants at once is undertaken. To reach the goal, a novel 1,8-naphthalimide-tagged polyacrylate (PAA-F2) is synthesized and tested separately and jointly with 1,8-naphthalimide-tagged bisphosphonate (HEDP-F) as a gypsum scale inhibitor within the frames of NACE Standard TM0374-2007. Here, it is found that at a dosage of 10 mg·dm⁻³ it provides a much higher inhibition efficiency (96%) than HEDP-F (32%). A PAA-F2 and HEDP-F blend (1:1 mass) has an intermediate efficacy (66%) and exhibits no synergism relative to its individual components. The visualization of PAA-F2 revealed a paradoxical effect: an antiscalant causes modification of the CaSO₄·2H₂O crystals habit, but does not interact with them, forming particles of its own solid complex [Ca-PAA-F2]. This paradox is interpreted in terms of the “nano/microdust” concept, prioritizing the bulk heterogeneous nucleation step, while an ability of the scale inhibitor to block the nucleus growth at the next steps is proven to be of secondary importance. At the same time, HEDP-F does not change the gypsum crystals morphology, although this antiscalant is completely located on the surface of the scale phase. The PAA-F2 and HEDP-F blend revealed an accumulation of both antiscalants in their own [Ca-PAA-F2/Ca-HEDP-F] phase with some traces of HEDP-F and PAA-F2 on the CaSO₄·2H₂O crystals surface. Thus, the visualization of two different antiscalants separately and jointly applied to gypsum deposition demonstrates differences in phosphonic and polymeric inhibitors location, and a lack of causal relationship between antiscalant efficiency and scale particle habit modification. Finally, it is shown that the confocal microscopy of several fluorescent antiscalant blends is capable of providing unique information on their interrelationships during scale deposition. Full article

In this study, the crystal habits of pyrite in the volcanic hot springs from Kamchatka, Russia were surveyed using scanning electron microscopy. Pyrite crystals occur either as single euhedral crystals or aggregates with a wide range of crystal sizes and morphological features. Single euhedral crystals, with their sizes ranging from ~200 nm to ~40 µm, exhibit combinations of cubic {100}, octahedral {111}, and pyritohedral {210} and {310} forms. Heterogeneous geochemical microenvironments and the bacterial activities in the long-lived hot springs have mediated the development and good preservation of the complex pyrite crystal habits: irregular, spherulitic, cubic, or octahedral crystals congregating with clay minerals, and nanocrystals attaching to the surface of larger pyrite crystals and other minerals. Spherulitic pyrite crystals are commonly covered by organic matter-rich thin films. The coexistence of various sizes and morphological features of those pyrite crystals indicates the results of secular interactions between the continuous supply of energy and nutritional elements by the hot springs and the microbial communities. We suggest that, instead of a single mineral with unique crystal habits, the continuous deposition of the same mineral with a complex set of crystal habits results from the ever-changing physicochemical conditions with contributions from microbial mediation. Full article

The quartz-K-feldspar-cemented breccia of Berglia-Glassberget in the Lierne municipality in central Norway forms an ellipsoid structure 250 m × 500 m in size. The hydrothermal breccia is barren in terms of economic commodities but famous among mineral collectors for being a large and rich site of crystal quartz of various colours and habits. Despite being a famous collector site, the mineralization is rather unique in respect to its geological setting. It occurs within Late Palaeoproterozoic metarhyolites of the Lower Allochthon of the Norwegian Caledonides regionally isolated from any other contemporaneous hydrothermal or magmatic event. In order to understand better the formation of the Berglia-Glassberget breccia, the chemistry, fluid inclusion petrography and age of the breccia cement were determined. Structural features indicate that the Berglia-Glassberget is a fault-related, fluid-assisted, hydraulic breccia which formed by single pulse stress released by a seismic event. ⁴⁰Ar-³⁹Ar dating of K-feldspar cement revealed a middle Triassic age (240.3 ± 0.4 Ma) for this event. The influx into the fault zone of an aqueous CO₂-bearing fluid triggered the sudden fault movement. The high percentage of open space in the breccia fractures with cavities up 3 m × 3 m × 4 m in size, fluid inclusion microthermometry, and trace element chemistry of quartz suggests that the breccia was formed at depths between 4 and 0.5 km (1.1 to 0.1 kbar). The origin of the breccia-cementing, CO₂-bearing Na-HCO₃-SO₄ fluid may have been predominantly of metamorphic origin due to decarbonation reactions (T > 200 °C) of limestones of the underlying Olden Nappe. The decarbonation reactions were initiated by deeply derived, hot fluids channelled to sub-surface levels by a major fault zone, implying that the breccia is situated on a deep-seated structure. Regionally, the Berglia-Glassberget occurs at a supposed triple junction of long-lived fault zones belonging to the Møre-Trøndelag, Lærdal-Gjende and the Kollstraumen fault complexes. These fault systems and the associated Berglia-Glassberget earthquake are the expression of rifting and faulting in northern Europe during the middle/late Triassic. Full article