Search Results (7)

In order to pursue the goal of low-carbon ironmaking, a new type of humic acid (HA)-based binder was applied to the preparation of oxidized pellets from vanadium-bearing titanomagnetite (VTM) in this work. Effects of the HA binder (or with limestone) on the balling, preheating, and roasting behaviors of VTM were comparatively studied with bentonite. The embedded features of each mineral phase in sintered pellets, especially the crystallization and growth state of hematite grains, were deeply investigated by XRD, optical microscopy, and SEM–EDS measures. The binder dosage can be cut down by 50% when HA was used instead of bentonite. Fine hematite grains in HA pellets evolved into plump interlocking grains with ~5% of limestone addition. Pseudobrookite and magnesioferrite spinel phase formed at the optimal sintering temperature of 1250 °C, which could hinder the crystallization of hematite and affect the strength of final pellets. Full article

Alendronate (ALN) is the most commonly prescribed oral nitrogen-containing bisphosphonate for osteoporosis therapy. However, its administration is associated with serious side effects. Therefore, the drug delivery systems (DDS) enabling local administration and localized action of that drug are still of great importance. Herein, a novel multifunctional DDS system based on the hydroxyapatite-decorated mesoporous silica particles (MSP-NH₂-HAp-ALN) embedded into collagen/chitosan/chondroitin sulfate hydrogel for simultaneous osteoporosis treatment and bone regeneration is proposed. In such a system, the hydrogel serves as a carrier for the controlled delivery of ALN at the site of implantation, thus limiting potential adverse effects. The involvement of MSP-NH₂-HAp-ALN in the crosslinking process was established, as well as the ability of hybrids to be used as injectable systems. We have shown that the attachment of MSP-NH₂-HAp-ALN to the polymeric matrix provides a prolonged ALN release (up to 20 days) and minimizes the initial burst effect. It was revealed that obtained composites are effective osteoconductive materials capable of supporting the osteoblast-like cell (MG-63) functions and inhibiting osteoclast-like cell (J7741.A) proliferation in vitro. The purposely selected biomimetic composition of these materials (biopolymer hydrogel enriched with the mineral phase) allows their biointegration (in vitro study in the simulated body fluid) and delivers the desired physicochemical features (mechanical, wettability, swellability). Furthermore, the antibacterial activity of the composites in in vitro experiments was also demonstrated. Full article

Black shale ore contains rich strategic metal resources such as vanadium, nickel, and molybdenum, but due to its complex composition, it is currently only used in the vanadium extraction industry. Metals such as nickel and molybdenum have not been effectively recovered, resulting in environmental pollution and resource waste. Using mineralogical features and a combination of beneficiation and metallurgy-based tests, the present work carried out feasibility studies of the combined beneficiation and metallurgy processes. The mineralogical features of the stone coal sample were studied using chemical analysis, an automatic mineral analyzer (BPMA), etc., and we identified the main phase composition, embedded characteristics, and particle size distribution of the associated strategic metals, vanadium, nickel, and molybdenum. The results showed that the grade of V₂O₅ in the stone coal was 1.29%, which was mainly present in carbonaceous clay and mica minerals. The nickel grade was 0.53%, mainly in the form of nickel–magnesium spinel and a small amount of nickel-containing magnesite. The stone coal contained 0.11% molybdenum; the mineral particles were fine, mostly in the form of molybdenite, and some were associated with carbonaceous matter and carbonaceous clay minerals. Based on the mineralogical feature, we proposed using the scrubbing–desliming and flotation process to enrich vanadium, nickel, and molybdenum. Our preliminary experiments obtained two products: vanadium–molybdenum-rich sludge and nickel-containing tailings. The V₂O₅ and molybdenum grades in the sludge were 4.10% and 0.44%, respectively, and the recovery was 41.31% and 51.40%, respectively. The nickel grade in the tailings was 1.49%. These products were roasted and leached. The vanadium, nickel, and molybdenum in the stone coal were effectively recovered through the beneficiation–metallurgy combination process, and the comprehensive utilization rate of the stone coal was improved. Full article

The present work reports the synthesis and characterization of polycaprolactone fibers loaded with particulate calcium magnesium silicates, to form composite materials with bioresorbable and bioactive properties. The inorganic powders were achieved through a sol–gel method, starting from the compositions of diopside, akermanite, and merwinite, three mineral phases with suitable features for the field of hard tissue engineering. The fibrous composites were fabricated by electrospinning polymeric solutions with a content of 16% polycaprolactone and 5 or 10% inorganic powder. The physico-chemical evaluation from compositional and morphological points of view was followed by the biological assessment of powder bioactivity and scaffold biocompatibility. SEM investigation highlighted a significant reduction in fiber diameter, from around 3 μm to less than 100 nm after the loading stage, while EDX and FTIR spectra confirmed the existence of embedded mineral entities. The silicate phases were found be highly bioactive after 4 weeks of immersion in SBF, enriching the potential of the polymeric host that provides only biocompatibility and bioresorbability. Moreover, the cellular tests indicated a slight decrease in cell viability over the short-term, a compromise that can be accepted if the overall benefits of such multifunctional composites are considered. Full article

Hydrothermal diagenesis during the Zagros Orogeny produced three phases of saddle dolomites (SD1, SD2, and SD3) and two phases of blocky calcites (CI and CII) in the studied sections of Bekhme Formation (Fm) (Campanian–Maastrichtian). Field observations, as well as petrographic, cathodoluminescence (CL), Scanning Elecron Microscope (SEM), and oxygen–carbon isotope analyses, indicated that the unit went through multiple submergence–emergence phases after or during hydrothermal diagenesis. These phases resulted in a characteristic calcretized 2–6-m-thick layer within the Bekhme Fm. Several pedogenic textures (e.g., alveolar, pisolite, and laminar fabric microfeatures) were observed. Strong evidence of microbial alteration and diagenesis in this formation brings new insights into its depositional history. The microbial activities developed on the original mineral surface were associated with a great variety of processes including dissolution, re-precipitation, replacement, open-space fillings, microporosity development, grain bridging, and micritization. Probable oxalate pseudomorphs embedded in these fabrics and regular filaments preserved along crystal boundaries suggest the activity of fungi, while frequent coccoidal, rod-like, and chain-like forms attached to the surfaces of dolomitic and calcitic crystals point to bacterial colonization. Extracellular polymeric substance (EPS) was often visible with fungal and bacterial forms. These features, together with stable isotope data, invoke that near-surface conditions occurred sporadically in the Bekhme Fm after the first generation of hydrothermal dolomitization. These new findings allow recognition of unreported sedimentological phases based on new evidence in the Spelek–Sulauk area during the Upper Cretaceous. Full article

The main aim of this study was to investigate the possible association between ¹⁸F–choline uptake and histopathological features of prostate biopsies such as the Gleason Group and the expression of both epithelial to mesenchymal transition (vimentin) and bone mineralization (bone morphogenetics protein (BMP)-2, runt-related transcription factor 2 (RUNX2), receptor activator of nuclear factor-κB ligand (RANKL), vitamin D receptor (VDR), and pentraxin 3 (PTX3) in situ biomarkers. To this end, we enrolled 79 consecutive prostate cancer patients that underwent both the ¹⁸F–choline PET/CT analysis and the prostate bioptic procedure. The standardized uptake value (SUV) average values were collected from ¹⁸F–choline PET/CT analysis whereas Gleason Group and immunostaining data were collected from paraffin-embedded sections. Histological classification showed a heterogenous population including both low/intermediate and high-grade prostate cancers. A significant increase of ¹⁸F–choline uptake in high-grade prostate lesions (Gleason Score ≥8) was found. Also, linear regression analysis showed a significant correlation between ¹⁸F–choline uptake and the number of vimentin, RANKL, VDR, or PTX3 positive prostate cancer cells. Conversely, we observed no significant association between ¹⁸F–choline uptake and the expression of bone biomarkers involved in the early phases of osteoblast differentiation (BMP-2, RUNX2). In conclusion, results here reported can lay the foundation for the use of ¹⁸F–choline positron emission tomography (PET)/computed tomography (CT) as a diagnostic tool capable of identifying high-grade prostate cancer lesions expressing bone biomarkers. Full article

Shock metamorphism of minerals in meteorites could help to understand the shock history of its parent body and also provide a window into the interior of the Earth. Although shock features in olivine have been well known within and adjacent to shock melt veins and shock melt pockets in meteorites, there are processes that are not yet completely understood. Ringwoodite is formed by crystallization from olivine melts or solid-state phase transformation of olivine. Typically, olivine clasts with a ringwoodite rim around an olivine core have been documented from only a handful of meteorites. Here we report results from GRV053684, a highly shocked L6 chondrite that was collected by Chinese Antarctic Research Expedition in 2006 to Antarctica. The investigations of the shock pressure history and the transformation mechanism of olivine to ringwoodite use optical microscope, electron probe microanalyzer (backscattered electron images, major element quantitative analyses, and quantitative wavelength-dispersive spectrometry elemental X-ray maps), and Raman spectrograph. Ringwoodite in the shock melt vein generally displays as Fe-rich (Fa_37-43) polycrystalline rims around Fe-poor (Fa_11-20) olivine core and as small individual clasts embedded in shock melt vein matrix. The difference in FeO between ringwoodite rim and olivine core implies that Fe was preferentially partitioned to ringwoodite. The occurrence of maskelynite (An₁₇) indicates a shock pressure ~30 GPa. The FeO and MgO diffusion indicates the transformation process of olivine to ringwoodite is a diffusion-controlled incoherent nucleation and growth. The spatial association between ringwoodite and the shock melt vein matrix suggests that high temperature plays a key role in prompting phase transformation. Full article