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The oil pipeline transportation of highly waxy oils when it is cold is accompanied by the deposition of paraffins in the inner surface of the pipeline. This study of the initial properties of the oil; the composition, structure, and nature of the components of normal alkanes in oil; and their influence on the aggregative stability of the resulting system makes it possible to find the best solutions to optimize the conditions of oil transportation with the lowest energy costs. This study shows that, according to the content of solid paraffin (14.0–16.2%), the oils of the Kumkol group of fields in Kazakhstan are highly waxy. They are characterized by high yield loss temperature values (+9–+12 °C), which also correlate with the values of the rheological parameters (τ0 1.389 Pa, 3.564 Pa). The influence of the temperature and shear rate on the shear stress and effective viscosity of the initial oils was studied. At temperatures below 20 °C, depending on the shear rate, there is an increase in the effective viscosity values (0.020 Pa∙s, 0.351 Pa∙s). The influence of the nature of solid hydrocarbons on the parameters of the paraffinization process and of the intensity of the paraffinization of the metal surfaces was studied. Our study shows that the main share of n-alkanes in the Kumkol and Akshabulak oils falls on paraffins of the C15–C44 group. The greater the temperature difference between the oil and the cold steel surface (≤40 °C), the lesser the amount of asphalt–resin–paraffin deposits (ARPDs) that fall out on the surface of the rod, although the content of long-chain paraffins prevails in these ARPDs. At the same time, the consistency of the released asphalt–resin–paraffin deposits (ARPDs) becomes denser, which makes their mechanical removal more difficult. Furthermore, the results of this study of the cooling rate shows that the rapid cooling of oils leads to the formation of a large number of crystallization centers, which leads to an increase in the values of the yield loss temperature and kinematic viscosity of the oils. [ABSTRACT FROM AUTHOR]

Gout results from elevated serum urate (SU) levels, or hyperuricemia, and is a globally widespread and increasingly burdensome disease. Recent studies have illuminated the pathophysiology of gout/hyperuricemia and its epidemiology, diagnosis, treatment, and complications. The genetic involvement of urate transporters and enzymes is also proven. URAT1, a molecular therapeutic target for gout/hyperuricemia, was initially derived from research into hereditary renal hypouricemia (RHUC). RHUC is often accompanied by complications such as exercise-induced acute kidney injury, which indicates the key physiological role of uric acid. Several studies have also revealed its physiological role as both an anti-oxidant and a pro-oxidant, acting as both a scavenger and a generator of reactive oxygen species (ROSs). These discoveries have prompted research interest in SU and xanthine oxidoreductase (XOR), an enzyme that produces both urate and ROSs, as status or progression biomarkers of chronic kidney disease and cardiovascular disease. The notion of "the lower, the better" is therefore incorrect; a better understanding of uric acid handling and metabolism/transport comes from an awareness that excessively high and low levels both cause problems. We summarize here the current body of evidence, demonstrate that uric acid is much more than a metabolic waste product, and finally propose the novel disease concept of "dysuricemia" on the path toward "normouricemia", or optimal SU level, to take advantage of the dual roles of uric acid. Our proposal should help to interpret the spectrum from hypouricemia to hyperuricemia/gout as a single disease category. [ABSTRACT FROM AUTHOR]

This research explores the symmetry in crystal growth processes to inform space-filling and stacking in the robotic construction process. The symmetry relations in crystals are examined from atomic to macro scale, from ordered to disordered to be implemented for modular blocks to fill the targeted volumes by stacking. [ABSTRACT FROM AUTHOR]

Gout results from elevated serum urate (SU) levels, or hyperuricemia, and is a globally widespread and increasingly burdensome disease. Recent studies have illuminated the pathophysiology of gout/hyperuricemia and its epidemiology, diagnosis, treatment, and complications. The genetic involvement of urate transporters and enzymes is also proven. URAT1, a molecular therapeutic target for gout/hyperuricemia, was initially derived from research into hereditary renal hypouricemia (RHUC). RHUC is often accompanied by complications such as exercise-induced acute kidney injury, which indicates the key physiological role of uric acid. Several studies have also revealed its physiological role as both an anti-oxidant and a pro-oxidant, acting as both a scavenger and a generator of reactive oxygen species (ROSs). These discoveries have prompted research interest in SU and xanthine oxidoreductase (XOR), an enzyme that produces both urate and ROSs, as status or progression biomarkers of chronic kidney disease and cardiovascular disease. The notion of “the lower, the better” is therefore incorrect; a better understanding of uric acid handling and metabolism/transport comes from an awareness that excessively high and low levels both cause problems. We summarize here the current body of evidence, demonstrate that uric acid is much more than a metabolic waste product, and finally propose the novel disease concept of “dysuricemia” on the path toward “normouricemia”, or optimal SU level, to take advantage of the dual roles of uric acid. Our proposal should help to interpret the spectrum from hypouricemia to hyperuricemia/gout as a single disease category.

Introduction: To analyze the dose-dependent preventive effect of a plant-based herbal product on the new crystal formation in a rat model. Materials and methods: A total of 42 rats were divided into 7 groups and zinc discs were placed into the bladder of rats to provide a nidus for the development of new crystal formation: Group 1: control, Group 2: 0.75 percent ethylene glycol (EG); Group 3: 0.75 percent EG plus 0.051 ml of the compound; Group 4: 0.75 percent EG plus 0.179 ml of the compound; Group 5: 0.75 percent EG plus 0.217 ml of the compound; Group 6: 0.75 percent EG plus 0.255 ml of the compound; Group 7 0.75 percent EG plus 0.332 of the compound). The analysis and comparison focused on the disc weights, changes in urinary oxalate and calcium levels, urinary pH, and the histopathologic evaluation of the inflammatory changes in the bladder after 14 days. Results: According to the evaluation of discs placed in the bladders of the animals, animals receiving the herbal compound on a dose-dependent basis showed a limited increase in the disc weights values after 14 days, despite a considerable increase in animals receiving EG alone (p = 0.001). Further evaluation of the increase in disc weights on a dose-dependent basis in different subgroups (from Groups 3 to 7) demonstrated that the limitation of crystal deposition began to be more prominent as the dose of herbal compound increased. This effect was more evident particularly in comparisons between group 7 and others, according to LSD multiple comparison tests (p = 0.001). As anticipated, there has been no discernible change in the weight of the discs in the control group. Although urinary calcium levels in animals of Groups 2, 6, and 7 were significantly higher than the other groups, we were not able to demonstrate a close correlation between urinary oxalate levels and the increasing dose levels. Even though mean urine pH levels were statistically considerably higher in Group 3, there was no statistically significant correlation between the oxalate and calcium levels between all groups, and no association was seen with the administration of herbal agents. The transitional epithelium between the three groups of animals' bladder samples did not exhibit any appreciable difference according to pathological analysis. Conclusions: In this animal model, the treatment of the compound was successful in lowering the amount of crystal deposition surrounding the zinc discs, most noticeably at a dosage of 0.332 ml, three times per day.

The history of the development and use of low-temperature electron microscopic methods of freeze-fracture, freeze-substitution and others in cryobiological research at the Institute for Problems of Cryobiology and Cryomedicine of the National Academy of Sciences of Ukraine is presented in this article. These methods' possibilities in studying the processes of crystal formation in cryoprotectant solutions, cell suspensions, and tissues under various freezing conditions are demonstrated. Some results of the analysis of ultrastructural changes in biological systems of various organization levels, at different stages of ontogenesis, under the influence of cooling in a wide temperature range (from 37 to -196°C) are presented. The use of a high resolution electron microscopic method in combination with an accessory technical equipment and some methodological techniques allowed to obtain fundamental results important for cryobiology on ice crystals formation and localization in the intracellular volume, the temperature-dependent transmembrane proteins redistribution, changes in the ultrastructure of erythrocytes and their membranes during hypothermic storage. [ABSTRACT FROM AUTHOR]

BACKGROUND: Maltose is an essential derivative of starch. To understand the processability and stability of maltose‐containing foods, material characterization of the phase and state transition from its amorphous state is required. Although the crystallization of amorphous maltose is well understood, few studies have reported the relationship between the crystallization and the glass transition temperature (Tg)‐related molecular mobility. In this study, water sorption, crystallization, Tg‐related α‐relaxation, and the corresponding time factor for amorphous maltose and maltose / whey protein isolate (WPI) mixtures are measured at various water activity (aw) levels and 25 °C. RESULTS: The water‐additive principle for maltose / WPI mixtures was observed at aw ≤ 0.440 at the molecular level, whereas the crystallization of amorphous maltose occurred at high aw values (≥0.534). The crystal formation and crystallization kinetics of amorphous maltose were affected by water and WPI at aw ≥ 0.534 and 25 °C, as determined by X‐ray diffraction. The relationship between Tg and the water content was fitted by the Gordon–Taylor model, and its constant showed a compositional dependence for the maltose / WPI mixtures. The α‐relaxation temperature of the amorphous samples decreased due to water plasticization, but increased with an increase in the WPI quantity. The Strength (S) value for amorphous maltose, which was a quantitative estimate of the compositional effects on molecular mobility, was based on the William–Landel–Ferry (WLF) equation. CONCLUSION: The S concept exhibits considerable potential for application in controlling the crystallization of amorphous maltose and improving the processability and stability of maltose‐containing foods. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The single crystal form and uncontrollable topography of CaCO3 in nature severely restrict its product grade and application. Meanwhile, lignin is still not utilized efficiently. In order to improve this, three types of lignin monomer model compounds as p‐coumaric acid (PCA), ferulic acid (FA), and sinapic acid (SA) are employed to induce the growth of CaCO3 to investigate the relationship between lignin structure and CaCO3 crystallization. The synthesized PCA and CaCO3 composite crystals (PC‐ACCs), FA and CaCO3 composite crystals (F‐ACCs), and SA and CaCO3 composite crystals (S‐ACCs) are characterized by field emission scanning electron microscope (FESEM), X‐ray diffraction (XRD), and Fourier transmission infrared spectroscopy (FTIR) to ascertain their molecular structures and crystal information. The growth rule of the acid and CaCO3 composite crystals (ACCs) induced by the three units is also explored. The results show that the vaterite and calcite of ACCs can be formed selectively. In the presence of PCA, FA, and SA, pH is the key factor on the phase selection of ACCs. The temperature and organic acid type also play important roles on the formation of CaCO3. The ACCs present distinguishing surface topographies at different temperatures. The number of methoxyl in the PCA, FA, and SA decides the phase ratio of vaterite and calcite in the ACCs. [ABSTRACT FROM AUTHOR]

Homogeneously Eu3+ doped LaOCl single crystals are firstly synthesized in a molten KCl-LiCl flux, and the well-shaped LaOCl:Eu3+ polyhedral micro-plates exhibit noticeable luminescent properties. The bulk LaOCl:Eu3+ micro-plate with a width of 1.03 μm and 1.37 μm in length shows a single crystal characteristic with the crystal face orientation of [00 1 ‾ ]. Both XRD patterns and EDS mapping indicate that the Eu3+ ions have been homogeneously doped into LaOCl lattice. LaOCl:Eu3+ nucleuses generated in molten KCl-LiCl flux at even 350 °C benefited to the decomposition of La(OH) 3 :Eu3+ precursor, and polyhedral LaOCl micro-plate is easily formed in molten KCl-LiCl salt due to the solid-ionic reaction and crystal growth. The luminescent properties of LaOCl:Eu3+ are firstly enhanced and then weakened with the increasing concentration of the doped Eu3+, 6% Eu3+ doped LaOCl:Eu3+ exhibits the best luminescent properties which can be used as a potential LED material. [ABSTRACT FROM AUTHOR]

Abstract—The features of nonclassical nucleation of crystals, which are related to the formation of stable prenucleus clusters of an intermediate phase in a crystal-forming medium, are considered. These clusters (quatarons) are primary protomineral particles, whose crystallization is among the possible scenarios of their evolution. The formation conditions and typical properties of quatarons are discussed. The importance of experiments on direct observation of prenucleus clusters and other objects of protomineral world is shown. [ABSTRACT FROM AUTHOR]

The formation of primary Fe-rich intermetallic compound crystals and the effect of TiB 2 and TiC inoculation during solidification of a hypereutectic Al-Fe alloy has been investigated. Both horizontal, near isothermal conditions and vertical, directional thermal gradient conditions were studied using laboratory and synchrotron X-ray radiography. TiB 2 and TiC inoculation enhanced formation of Fe-rich intermetallics under all experimental conditions. Near isothermal solidification resulted in the highest intermetallic number density and average formation rate, whilst increasing the thermal gradient reduced both. A model for intermetallic crystal formation is proposed to explain the effect of thermal gradient and cooling rate on the intermetallic number density and average formation rate. [ABSTRACT FROM AUTHOR]

• The slag viscosity increases with the SiO 2 /CaO above the liquidus temperature, while it decreases below the liquidus temperature. • The reduction of Si-O-Ca-O units with larger ionic radii improve the fluidity of the slag. • As the SiO 2 /CaO ratio increased, the presence of phosphorus promoted the polymerization of the silicate network. • The optimal slag discharge temperature range for the slag with a composition of 85 wt% (SiO 2 + CaO) and a SiO 2 /CaO ratio of 0.9 was 1252 °C-1285 °C. Slag within suitable viscosity range is important for well controlled slag tapping of phosphorus reduction process in electrical furnace. The suitable slag viscosity depends on the adjustment of SiO 2 /CaO by adding silica. However, the influence of SiO 2 /CaO on slag viscosity and structure at slag tapping condition is still unknown. In this work, it is found that the slag viscosity increased slightly with increasing SiO 2 /CaO above the liquidus temperature. This is because the reduction of free oxygen ions (O2–) leads to an increase of the polymerization degree. However, the slag viscosity decreased as the SiO 2 /CaO ratio increased below the liquidus temperature. The weakening of the crystallization tendency, the formation of eutectic mixtures, and the reduction of Si-O-Ca-O units with larger ionic radii improve the fluidity of the slag. In addition, the presence of phosphorus slightly promoted the polymerization of the silicate network with increasing SiO 2 /CaO. This is caused by the increasing proportion of modified cations released by phosphorus from the silicate network. Meanwhile, the increasing SiO 2 /CaO decreased the polymerization degree of the aluminate structure due to the transition of [AlO 4 ] to [AlO 5 ]. The optimal slag discharge temperature range for the slag with a composition of 85 wt% (SiO 2 + CaO) and a SiO 2 /CaO ratio of 0.9 was 1252 °C-1285 °C. [ABSTRACT FROM AUTHOR]

This work presents a study of cenosphere separation from lignite high-calcium (~24 wt.%) fly ash by centrifugal method; this is the first report for Mae Moh, Thailand, fly ash with this high calcium content using this technique. The effect of centrifugal parameters on cenosphere yield and properties were investigated. Those properties include physical properties, morphology, chemical composition, and mineral phases. The recovery yields are in the range of 0.34–0.64%, approximately one third of the yield obtained from the general gravity settling method. Density, particle size, and morphology of the collected cenospheres appeared to be independent of sequence of the applied speeds and times. Interrelation of chemical composition and mineral phases was established, with the focus on calcium carbonate formation on cenosphere surface and crystallite size study. The study has revealed the preferential formation of calcite–(104) peak is observed–by cenospheres, with stable growth behavior of crystallite sizes obtained from all the centrifugal conditions. The result was compared to that obtained from the sink-float method for a better insight. The influence and limitation of the centrifugal method, the varied parameters, and the relevant reaction pathways on crystal growth process in terms of important dissolving species (i.e., Ca2+ and CO32−) behavior in the ash suspension were discussed.

The scientific and applied aspects of growing single crystals of refractory metals using plasma and induction heating sources are considered. The technological advantages of combined plasma-induction heating when growing large single crystals of refractory metals, in particular tungsten and molybdenum, are shown. The design of the UP-122M pilot plant for growing flat single crystals of tungsten and molybdenum and its technical characteristics are given. The problems of formation of the structure of tungsten single crystals under the conditions of hybrid plasma-induction heating are considered, and its advantages are compared with other heating methods. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation into crystal formation in NBS system for glaze with metallic appearance experimentally produced by embedding metallic substances as AgNO 3, BaCl 2 , CuSO 4 and CuCO 3 and their characterizations. Composition of NBS was calculated by using Seger Method. According to the quantity of components, crystal phases were marked on Na 2 O-B 2 O 3 -SiO 2 ternary diagrams. The amount of AgNO 3 (2 wt%) was kept constant that other metallic substances (BaCl 2 , CuSO 4 and CuCO 3) were added in an amount of 5 wt% as had an impact on the mechanism of crystalline phase growth. These glaze compositions were applied over the surface of the commercial bodies and fired at 1040 °C, cooled to 750 °C and then reduced in the reductive atmosphere in order to obtain metallic layer on glaze surfaces for 20 min. These glaze layers characterized under mineralogical, microstructural and chemical points of view by means of X-Ray Diffraction (XRD), optical microscopy (OM), Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM-EDX) and Ulltraviolet Visible Spectroscopy (UV–Vis) techniques. The results showed that silver and copper particles/crystals developed near/on the glaze surfaces creating multicolored metallic shine. Diffusion of metallic particles/crystals shown on the glazed layers as Ag and Cu followed by nucleation and growth in a reductive atmosphere. [ABSTRACT FROM AUTHOR]

• Single and accumulated mutations of conserved cysteine residues in Cry1Ac were performed. • Cysteine residues in Cry1Ac are not essential for bipyramidal crystal formation and toxicity. • Bipyramidal crystal formation of Cry1 protoxins might depend on other residues in the C-terminal half. To evaluate the function of conserved cysteine residues in Cry1Ac protoxin, we constructed a series of Cry1Ac mutants in which single or multiple cysteine residues were replaced with serine. It was found that cysteine substitution had little effect on the protoxin expression and bipyramidal crystal formation. Bioassays using Plutella xylostella larvae showed that two mutants with fourteen cysteine residues in the C-terminal half and all sixteen residues replaced had similar toxicity as wildtype Cry1Ac protoxin. Our study suggests that the conserved cysteine resudues in the Cry1Ac protoxin are not essential for deposition into a bipyramidal crystal even though the C-terminal half was directly involved in crystal formation. [ABSTRACT FROM AUTHOR]

Scaling in reverse osmosis facilities, boilers, heat exchangers, evaporation plants, and oilfield applications is a serious problem worldwide. In order to provide a new insight into the mechanism of the scale formation and inhibition, a novel fluorescent‐tagged bisphosphonate scale inhibitor 1‐hydroxy‐7‐(6‐methoxy‐1,3‐dioxo‐1H‐benzo[de]isoquinolin‐2(3H)‐yl)heptane‐1,1‐diyl‐di(phosphonic acid), (HEDP−F) was synthesized and used for fluorescent microscope visualization of gypsum crystal formation in supersaturated aqueous solutions. The visualization of HEDP−F location on gypsum crystals has demonstrated that the bisphosphonate molecules do not act as they are expected to do according to the current scale inhibition theory. At ambient temperature the gypsum macrocrystals are found to form, and then to grow without visible sorption of bisphosphonate on the crystal edges or any other gypsum crystal growth centers. A tentative nonconventional mechanism of scale inhibition in the bulk supersaturated aqueous solutions of gypsum is proposed. [ABSTRACT FROM AUTHOR]

Several types of crystals having different color appeared in the synthesis of assembled complex of mixed crystals with three metals. [H2(bpp)][M(NCS)4] changed to 1D chain polymer (M(NCS)2(bpp)) by releasing HNCS from the cation and anion in a reaction vessel.

Background: Epidural steroid injections are widely used to treat spinal and radiating pain. However, crystal formation has recently been reported in mixtures of ropivacaine and nonparticulate steroids, commonly used in epidural steroid injections., Objectives: Our study assessed the physicochemical stability of mixtures of different nonparticulate steroids and ropivacaine and aimed to propose a safe regimen for epidural steroid injections., Study Design: An in vitro protocol was used to examine the physicochemical stability of epidural steroid injection mixtures most commonly used at our institution., Setting: In vitro laboratory study., Methods: Twelve solutions were prepared by mixing 0.75% or 0.2% ropivacaine with dexamethasone or betamethasone at volume ratios of 1:1, 2:1, and 3:1 in propylene syringes at 24°C. The physical properties of the mixtures were observed with the naked eye and under a microscope, and their pH was measured. The concentration of each drug in the mixture was evaluated using high-performance liquid chromatography., Results: None of the ropivacaine and dexamethasone mixtures showed macroscopic or microscopic crystal formation after 2 hours, and there were no significant changes in pH. The concentrations of the 2 drugs remained stable for up to 2 hours. In contrast, at least 10 mu-m crystals were observed microscopically and macroscopically in all mixtures of ropivacaine and betamethasone; the ropivacaine concentration was reduced by > 10% after one hour., Limitations: Confirming the stability of drugs in vitro does not ensure that their pharmacokinetics and pharmacodynamics remain unaltered in vivo., Conclusion: The combination of ropivacaine and betamethasone should be avoided because of their physicochemical instability. Combinations of ropivacaine and dexamethasone should be administered cautiously because they are more physicochemically stable than combinations of ropivacaine and betamethasone.

The mechanism of synthesis of fine-crystalline corundum from aluminum hydroxide under induced nucleation conditions in a supercritical water fluid at 400°C and initial pressure of 26.4 MPa followed by exposure in the synthesis medium was studied. The crystal size distribution was analyzed by electron microscopy. The use of the lognormal function to describe the crystal size distribution of the synthesized corundum particles was substantiated. The possibility of using the lognormal particle size distribution function and the time dependence of its parameters to reveal the routes of product formation was analyzed. The dimensional spectrum of microcrystals has four components, whose appearance is associated with different routes of product formation. The number of distribution components remains unchanged during prolonged exposure, but their average characteristics have different time dependences. The mass redistribution during recrystallization, generally leading to a decrease in the average crystal size, is explained by differences in the crystal structure mobility of different components. It was concluded that the states of corundum in the newly formed crystals and in the overgrown layer on the particles of the inducing additive are different. [ABSTRACT FROM AUTHOR]

Compositions of Cu-Cu 2 O crystal films were fabricated using electrochemical deposition (ECD) with a strategy of potential pulse settings. The Cu-Cu 2 O films were prepared by controlling the potentials and deposition periods of ECD processes. Intensities of Cu and Cu 2 O crystals were revealed by X-ray diffraction (XRD) spectral data. Results demonstrated that the Cu and Cu 2 O crystal compositions were significantly influenced by the potential and deposition period settings. Polycrystalline Cu 2 O films were formed by the ECD at all tested potential settings. However, Cu-Cu 2 O crystals were formed at potential more negative than −0.4 V and with long deposition times. The grain sizes of Cu 2 O and Cu crystals fabricated by ECD were estimated to be 50 and 51 nm, respectively. We verified that the reaction mechanism of Cu 2 O occurred in the solution phase, and Cu 2 O transformed into Cu in the solid phase inside the deposition films. The compositions of Cu-Cu 2 O crystal films can be controlled by a potential pulse strategy with adjusted potential range and pulse period settings. The formation of Cu-Cu 2 O crystal films during ECD was also discussed. [ABSTRACT FROM AUTHOR]

The use of a phase field approach to simulate solidification of metallic alloys has many computational advantages, but if obtaining quantitative results relies on the interface between phases being physically realistic, the computational advantage is much reduced. We propose here a method for compensating for a computationally convenient large interface width by simply transferring a numerically derived 1D steady state anti-trapping current to a general non-steady 2D simulation. The method proposed is not restricted to dilute or ideal materials and has a high degree of interface width independence, illustrated here with two models, illustrating a broad applicability for the approach. [ABSTRACT FROM AUTHOR]

We present methods and results for the simulation of faceted and dendritic crystal growth. Using a thermodynamically realistic isothermal alloy model for AlSi we demonstrate, in confirmation of experimental observations, a change in morphology from perfectly faceted hexagons at smaller undercooling to dendritic growth at larger undercoolings. We also demonstrate that there exists a cut off temperature which separates the two distinct morphologies, and indeed hybrid morphologies. These results suggest that the mechanism for morphology variation observed experimentally primarily lies in anisotropic surface free energy modelling, which we adopt in preference to kinetic anisotropy. [ABSTRACT FROM AUTHOR]

The ability of Halomonas maura to bioprecipitate carbonate and sulphate crystals in solid media at different manganese concentrations has been demonstrated in this study for the first time. The precipitated minerals were studied by X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The precipitated minerals were different based on the manganese concentration present in the medium and the incubation time. In the absence of manganese, H. maura formed pseudokutnahorite crystals; in the presence of manganese, the concentration in the culture medium determined the precipitation carbonates, such as rhodochrosite and dolomites. However, in the presence of low concentrations of manganese chloride (MnCl) (5 g/l), kutnohorite crystals were also formed. Finally, when H. maura was grown in the presence of manganese, small amounts of sulphate crystals (such as bassanite and gypsum) were detected. Our study of the precipitated minerals showed an active role of H. maura in the biomineralisation process, but the geochemical conditions, and the manganese concentrations in particular, were clearly influential. [ABSTRACT FROM AUTHOR]

In this report, we summarize our experimental and theoretical investigations in the zinc(II) imidazolate, [Zn(im)2], and zinc(II) 4,5-dichloroimidazolate, [Zn(dcim)2], systems that have been published previously. This comprises a study on the thermodynamic stabilities of the two densest phases with coi and zni framework structures in the [Zn(im)2] system including the discovery and characterization of a new [Zn(im)2·0.5py]-neb phase (py = pyridine), a study on the mechanism of formation of the [Zn(im)2]-zni phase as well as a study on the discovery and characterization of a new [Zn(dcim)2]-SOD phase. In addition, we present as yet unpublished work. This concerns the discovery and characterization of a new [Zn(im)2·0.5mor]-neb phase (mor = morpholine) and investigations of the mechanisms of crystallization of [Zn(im)2·0.5py]-neb and [Zn(im)2·0.5mor]-neb as well as an evalutation of time-resolved SAXS/WAXS data recorded in-situ during the formation of [Zn(im)2]-zni. [ABSTRACT FROM AUTHOR]

Perovskite-based photovoltaic devices have recently achieved impressively high efficiencies beyond 15% and gained great interest. We show here the formation of perovskite cluster overlayer structures which consist of individual perovskite grains on top of mesoporous TiO2 films, coexisting with the randomly distributed nanocrystals within the films. Perovskite solution concentration was found to play an important role in modulating the perovskite crystallization and cluster overlayer formation process. Absorbance increase in visible wavelength range and shift of photoluminescence (PL) responses of perovskite films due to the effect of precursor concentration change were observed and investigated in detail. The crystallographic analysis of the CH3NH3PbI3 films shows a gradual decrease of the perovskite lattice parameters and shrinkage of unit volume as precursor solution concentration increases, which is correlated to the changes of optical properties. Finally, perovskite-based solar cell device performance was enhanced at higher precursor concentration. [ABSTRACT FROM AUTHOR]

Abstract: The calcareous spicules from sponges, e.g. from Sycon raphanus, are composed of almost pure calcium carbonate. In order to elucidate the formation of those structural skeletal elements, the function of the enzyme carbonic anhydrase (CA), isolated from this species, during the in vitro calcium carbonate-based spicule formation, was investigated. It is shown that the recombinant sponge CA substantially accelerates calcium carbonate formation in the in vitro diffusion assay. A stoichiometric calculation revealed that the turnover rate of the sponge CA during the calcification process amounts to 25 CO2 s−1 ×molecule CA−1. During this enzymatically driven process, initially pat-like particles are formed that are subsequently transformed to rhomboid/rhombohedroid crystals with a dimension of ∼50μm. The CA-catalyzed particles are smaller than those which are formed in the absence of the enzyme. The Martens hardness of the particles formed is ∼4GPa, a value which had been determined for other biogenic calcites. This conclusion is corroborated by energy-dispersive X-ray spectroscopy, which revealed that the particles synthesized are composed predominantly of the elements calcium, oxygen and carbon. Surprising was the finding, obtained by light and scanning electron microscopy, that the newly formed calcitic crystals associate with the calcareous spicules from S. raphanus in a highly ordered manner; the calcitic crystals almost perfectly arrange in an array orientation along the two opposing planes of the spicules, leaving the other two plane arrays uncovered. It is concluded that the CA is a key enzyme controlling the calcium carbonate biomineralization process, which directs the newly formed particles to existing calcareous spicular structures. It is expected that with the given tools new bioinspired materials can be fabricated. [Copyright &y& Elsevier]

Abstract: The inorganic scaffold of the spicules, the skeletal elements of the calcareous sponges, is formed of calcium carbonate (CaCO3). The growth of the approximately 300-μm large spicules, such as those of the calcareous sponge Sycon raphanus used in the present study, is a rapid process with a rate of about 65 μm/h. The formation of CaCO3 is predominantly carried out by the enzyme carbonic anhydrase (CA). The enzyme from the sponge S. raphanus was isolated and prepared by recombination. The CA-driven deposition of CaCO3 crystallites is dependent on temperature (optimal at 52 °C), the pH value of the reaction assay (7.5/8.0), and the substrate concentration (CO2 and Ca2+). During the initial phase of crystallite formation, ≈40 μm large round-shaped deposits are formed that remodel to larger prisms. These crystal-like prisms associate to each other and form either rope-/bundle-like aggregates or arrange perfectly with their smaller planes along opposing surfaces of the sponge spicule rays. The CA-dependent CaCO3 deposition can be inhibited by the CA-specific inhibitor acetazolamide. The Michaelis–Menten constant for the CA-driven mineralization has been determined to be around 8 mM with respect to CaCO3. The deposits formed have a Martens hardness of ≈5 GPa. The data presented here highlights for the first time that calcite deposition in the sponge system is decisively controlled enzymatically. This data will contribute to the development of new strategies applicable for the fabrication of novel biomaterials. [Copyright &y& Elsevier]

Background Melamine and cyanuric acid (M/CA), when orally administered together to rats, can induce crystal formation within renal tubules and cause acute kidney injury. Methods To investigate the pathomechanism of crystal-induced nephritis, melamine and/or cyanuric acid were administered to 3-week-old (young) and 8-week-old (adult) rats, respectively. Results Crystal formation, blood urea nitrogen elevation, tubular cell injury and macrophage infiltration were noted in rats fed with M/CA, but not in rats fed with vehicle, melamine or CA alone. These parameters were significantly higher in young rats than those in adult rats fed with M/CA 200 mg/kg body weight (BW) for 3 days. Krüppel-like factor 5 (KLF5) was expressed on distal tubule cells, especially when crystals deposited within the lumens. Both mRNA and protein levels were higher in young rats than those in adult rats fed with M/CA (200 mg/kg BW). KLF5 expression has been shown to modulate renal tissue cytokine production, and we found that proinflammatory cytokines like monocyte chemoattractant protein-1 and interlukin-6 were increased in kidney tissues of young rats fed with M/CA for 3 days. In contrast, interlukin-10, an anti-inflammatory cytokine, was upregulated in kidneys of adult rats fed with M/CA for 3 days. Conclusions Crystals are prone to deposition in distal tubules of young rats fed with M/CA. M/CA Crystal-related nephritis might be induced by the KLF5 expression, which modulated macrophage recruitment and proinflammatory cytokine production, subsequently leading to renal tubular injury and interstitial inflammation. [ABSTRACT FROM PUBLISHER]

In this work, a bioactive glass was deposited on the alumina disk specimens by radio-frequency magnetron sputtering to study crystal formation ability in artificial saliva. Bioactive glass-coated specimens were immersed in artificial saliva for 1 week and 6 months. The specimens were observed with a scanning electron microscope (SEM) and the composition was determined by energy dispersive spectroscopy (EDS). The crystals that formed on the specimens were analyzed by Raman spectroscopic analysis and Micro-X-ray diffraction. SEM photomicrographs showed the formation of needle-like structures after immersion for 1 week, and tabular structures formed on the surface of the specimen for 6 months. EDS showed that both the needle-like and tabular structures were enriched with Ca and P. Raman and Micro-XRD spectra for the tabular structure showed peaks that may correspond to calcium phosphate. Thus, when immersed in artificial saliva, bioactive glass-coated alumina produced a crystal which might be calcium phosphate. [ABSTRACT FROM AUTHOR]

Background. The ‘fixed particle’ theory states that, besides crystal formation in the tubular fluid, crystal adhesion to the tubular epithelium is a prerequisite for the development of intratubular nephrocalcinosis. It has been hypothesized that the tubular epithelium, in order to bind crystals, needs to be phenotypically altered. Whereas most evidence hereto is provided by in vitro experiments, we set out to illustrate this theory in vivo. [ABSTRACT FROM PUBLISHER]

The authors discusses various issues concerning nephrocalcinosis, a form of renal stone disease characterized with a macroscopic concrement of inorganic and organic material in the renal calyces and/or pelvis. They offer clinical information on intratubular and interstitial nephrocalcinosis, including their mechanisms and possible consequences. They reveal that various insults or conditions could turn a normal tubular epithelial phenotype into a penotype that can bind crystals and form nephrocalcinosis.

Crystal formation in mice could not be induced either by the administration of ethylene glycol or by glycolate. To clarify the reasons for the difference among these oxalate precursors in mice, we studied renal tubular epithelial injury by immunohistochemical staining of oxidative stress and observing microstructures. Daily intra-abdominal injection of saline solution [10 ml/(kg day)], ethylene glycol[(48.3 mmol/(kg day)], glycolate [1.31 mmol/(kg day)], and glyoxylate [1.35 mmol/(kg day)] into C57BL/6 male mice (8 weeks) was performed for 7 days. Immunohistochemical staining of superoxide dismutase (SOD) and malondialdehyde (MDA), and transmission electron microscopy (TEM) of renal tubular epithelial cells were performed to observe oxidative stress and morphological changes, respectively. Decreased SOD and increased MDA were shown only in glyoxylate-treated mouse kidneys. The TEM study with glyoxylate-treated mouse kidneys demonstrated that the internal structure of mitochondria in renal tubular cells underwent destruction and vacuolization, and microvilli density decreased. These changes in renal tubular cells were located in the crystal-forming area. However, such changes were not detected in the other groups. Each precursor of oxalate induces different changes in renal epithelial cells regarding oxidative stress and the microstructural changes. It is suggested that calcium oxalate crystal formation requires cell injury and morphological changes of renal epithelial tubular cells induced by glyoxylate administration in the mouse kidney. [ABSTRACT FROM AUTHOR]

Thermal history and solute precipitation behavior of suspended solution droplets of sodium chloride (NaCl), magnesium sulphate (MgSO4), and zirconium hydroxychloride (ZrO(OH)Cl) evaporating at atmospheric and reduced pressures are studied. Experimental measurements on the variation of droplet diameter, solution concentration, and temperature during the evaporation period are presented and discussed. The results of solute precipitation behavior in solution droplets observed under an optical microscope are displayed and discussed. Results indicate that reducing the pressure (∼ 33 kPa) results in a change in the solution droplet evaporation rate, but the thermal histories of a particular solution droplet are similar at the atmospheric and reduced pressures. At atmospheric and reduced pressures used in this study, the d2 law for solution droplets is valid at early stages of the evaporation and before the solute precipitation initiates. Drying of MgSO4 and ZrO(OH)Cl solution droplets results in the formation of spherical particles, whereas drying of spherical NaCl solution droplets results in the formation of cubic particles. [ABSTRACT FROM AUTHOR]

In the current study, the leachability of lead from the PbO-Fe2O3-SiO2-Na2O vitrification system was examined by the application of DIN 38414 S4 and TCLP (Toxicity Characteristic Leaching Procedure) standard leaching tests. Various compositions, containing industrial or artificially created solid waste, were examined. Among the main conclusions from the results obtained was that the initial lead content, expressed as PbO and varied between 4–24% w/w, does not influence directly the release of lead from the vitrified samples. The other oxides, as well as other factors e.g. crystal formation on the glass surface, proved to be more important. Similar data were obtained regarding the content of iron oxide (the initial content of Fe2O3 varied from 30–54% w/w), although in this case the sodium concentrations measured in the leachates were generally found to increase with increasing initial iron oxide content and with the respective formation of crystals. The stoichiometry of lead and sodium, as measured in the leachates, was not constant for all the examined cases, showing that the mechanism of release depends upon the initial compositions and the presence of crystals on the glass surface. Improved results, regarding leachability and homogeneity without the presence of crystallites on the glass surface, were obtained when the initial ratio SiO2/Na2O (% w/w) was 2.33. By maintaining this ratio and when the examined waste was gradually added in the initial composition, the results obtained, concerning sodium concentration and pH values, can be described mathematically, by introducing an appropriate constant factor. [ABSTRACT FROM AUTHOR]

Osteopontin (OPN) is a phosphorylated protein of wide tissue distribution that is found in association with dystrophic calcification including in the organic matrix of kidney stones. It is a strong inhibitor of crystal formation and growth in vitro, but there is still debate regarding its effects upon crystal adhesion to tubular epithelial cells. In this brief review, we will outline the evidence implicating OPN in stone disease with the primary emphasis being on the interaction of OPN with calcium oxalate (CaOx), the major constituent of calcium containing stones. Finally, preliminary data is presented regarding the amounts and features of OPN present in the urine of stone formers and normal individuals. [ABSTRACT FROM AUTHOR]

Gout and pseudogout are inflammatory arthritides due to monosodium urate and calcium pyrophosphate dihydrate crystal formation. Both are prevaient among geriatric patients, and can present as acute mono- or oligoarticular disease, or as a chronic polyarthropathy resembling osteoarthritis or rheumatoid arthritis. Gout in the geriatric patient is a disease affecting women, commonly associated with diuretic usage, often involves the fingers, may be complicated by the development of masses of uric acid crystals (tophi) in soft tissues, and is frequently polyarticular. Pseudogout in the geriatric patient has a variety of clinical presentations, may be acute or chronic, and should be considered in evaluating any patient with osteoarthritis occurring in an atypical distribution. Treatment includes the use of nonsteroidal antiinfiammatory drugs, colchicine, or corticosteroids. Gout may be impacted by dietary factors, weight reduction, and avoidance of certain forms of alcohol; uric acid-lowering agents are effective for refractory or chronic tophaceous disease. INSET: Take Home points. [ABSTRACT FROM AUTHOR]

Calcium oxalate crystal formation in plants appears to play a central role in a variety of important functions, including tissue calcium regulation, protection from herbivory, and metal detoxification. Evidence is mounting to support ascorbic acid as the primary precursor to oxalate biosynthesis. The ascorbic acid utilized in oxalate biosynthesis is synthesized directly within the calcium oxalate crystal-accumulating cell, called the crystal idioblast. Several unique features of the crystal idioblast have been proposed as factors that influence calcium oxalate formation. These features include an abundance of endoplasmic reticulum (ER), acidic proteins, cytoskeletal components, and the intravacuolar matrix. A number of mutants defective in different aspects of calcium oxalate crystal formation have been isolated. Cellular and biochemical characterizations of the various mutants have revealed mutations affecting crystal nucleation, morphology, distribution, and/or amount. Such mutants will be useful tools in continued efforts to decipher the pathways of crystal formation and function in plants. [Copyright &y& Elsevier]

Twenty-four–hour urine chemistries and the risk of kidney stones among women and men. Background. Results of a 24-hour urine collection are integral to the selection of the most appropriate intervention to prevent kidney stone recurrence. However, the currently accepted definitions of normal urine values are not firmly supported by the literature. In addition, little information is available about the relationship between risk of stone formation and the levels of urinary factors. Unfortunately, the majority of previous studies of 24-hour urine chemistries were limited by the inclusion of recurrent stone formers and poorly defined controls. Methods. We obtained 24-hour urine collections from 807 men and women with a history of kidney stone disease and 239 without a history who were participants in three large ongoing cohort studies: the Nurses' Health Study I (NHS I; mean age of 61 years), the Nurses' Health Study II (NHS II; mean age of 42 years), and the Health Professionals Follow-up Study (HPFS; mean age of 59 years). Results. Mean 24-hour urine calcium excretion was higher and urine volume was lower in cases than controls in NHS I (P ≤ 0.01), NHS II (P ≤ 0.13) and HPFS (P ≤ 0.01), but urine oxalate and citrate did not differ. Among women, urine uric acid was similar in cases and controls but was lower in cases in men (P = 0.06). The frequency of hypercalciuria was higher among the cases in NHS I (P = 0.26), NHS II (P = 0.03), and HPFS (P = 0.02), but 27, 17, and 14% of the controls, respectively, also met the definition of hypercalciuria. The frequency of hyperoxaluria did not differ between cases and controls, but was three times more common among men compared with women. After adjusting for the other urinary factors, the relative risk of stone formation increased with increasing urine calcium levels and concentration in all three cohorts but not in a linear fashion. Compared with individuals with a urine calcium concentration of <75 mg/L, the relative risk of stone formation among those with a urine calcium concentration of ≥200 mg/L for NHS I was 4.34 (95% CI, 1.59 to 11.88), for NHS II was 51.09 (4.27 to 611.1), and for HPFS was 4.30 (1.71 to 10.84). There was substantial variation in the relative risks for stone formation for the concentration of other urine factors within the different cohorts. Conclusions. The traditional definitions of normal 24-hour urine values need to be reassessed, as a substantial proportion of controls would be defined as abnormal, and the association with risk of stone formation may be continuous rather than dichotomous. The 24-hour urine chemistries are important for predicting risk of stone formation, but the significance and the magnitudes of the associations appear to differ by age and gender. [ABSTRACT FROM AUTHOR]

This work presents a study of cenosphere separation from lignite high-calcium (~24 wt.%) fly ash by centrifugal method; this is the first report for Mae Moh, Thailand, fly ash with this high calcium content using this technique. The effect of centrifugal parameters on cenosphere yield and properties were investigated. Those properties include physical properties, morphology, chemical composition, and mineral phases. The recovery yields are in the range of 0.34–0.64%, approximately one third of the yield obtained from the general gravity settling method. Density, particle size, and morphology of the collected cenospheres appeared to be independent of sequence of the applied speeds and times. Interrelation of chemical composition and mineral phases was established, with the focus on calcium carbonate formation on cenosphere surface and crystallite size study. The study has revealed the preferential formation of calcite–(104) peak is observed–by cenospheres, with stable growth behavior of crystallite sizes obtained from all the centrifugal conditions. The result was compared to that obtained from the sink-float method for a better insight. The influence and limitation of the centrifugal method, the varied parameters, and the relevant reaction pathways on crystal growth process in terms of important dissolving species (i.e., Ca2+ and CO32−) behavior in the ash suspension were discussed. [ABSTRACT FROM AUTHOR]