Nanoparticles Functionalised with Re(I) Tricarbonyl Complexes for Cancer Theranostics

Globally, cancer is the second (to cardiovascular diseases) leading cause of death. Regardless of various efforts (i.e., finance, research, and workforce) to advance novel cancer theranostics (diagnosis and therapy), there have been few successful attempts towards ongoing clinical treatment options as a result of the complications posed by cancerous tumors. In recent years, the application of magnetic nanomedicine as theranostic devices has garnered enormous attention in cancer treatment research. Magnetic nanoparticles (MNPs) are capable of tuning the magnetic field in their environment, which positively impacts theranostic applications in nanomedicine significantly. MNPs are utilized as contrasting agents for cancer diagnosis, molecular imaging, hyperfusion region visualization, and T cell-based radiotherapy because of their interesting features of small size, high reactive surface area, target ability to cells, and functionalization capability. Radiolabelling of NPs is a powerful diagnostic approach in nuclear medicine imaging and therapy. The use of luminescent radioactive rhenium(I), 188/186Re, tricarbonyl complexes functionalised with magnetite Fe3O4 NPs in nanomedicine has improved the diagnosis and therapy of cancer tumors. This is because the combination of Re(I) with MNPs can improve low distribution and cell penetration into deeper tissues.

Impact of Mineral Reactive Surface Area on Forecasting Geological Carbon Sequestration in a CO2-EOR Field

Mineral reactive surface area (RSA) is one of the key factors that control mineral reactions, as it describes how much mineral is accessible and can participate in reactions. This work aims to evaluate the impact of mineral RSA on numerical simulations for CO2 storage at depleted oil fields. The Farnsworth Unit (FWU) in northern Texas was chosen as a case study. A simplified model was used to screen representative cases from 87 RSA combinations to reduce the computational cost. Three selected cases with low, mid, and high RSA values were used for the FWU model. Results suggest that the impact of RSA values on CO2 mineral trapping is more complex than it is on individual reactions. While the low RSA case predicted negligible porosity change and an insignificant amount of CO2 mineral trapping for the FWU model, the mid and high RSA cases forecasted up to 1.19% and 5.04% of porosity reduction due to mineral reactions, and 2.46% and 9.44% of total CO2 trapped in minerals by the end of the 600-year simulation, respectively. The presence of hydrocarbons affects geochemical reactions and can lead to net CO2 mineral trapping, whereas mineral dissolution is forecasted when hydrocarbons are removed from the system.

Reactive transport model of kinetically controlled celestite to barite replacement

<p>Barite formation is of concern for many sustainable utilisations of the geological subsurface, ranging from oil and gas extraction to geothermal reservoirs, and also acts as a scavenger mineral for the retention of radium for nuclear waste disposal. The surface reaction-controlled nature of its formation in these dynamic systems entails a strong sensitivity of the host rock's permeability towards heterogeneities and boundary conditions. The impact of precipitation on effective flow properties can vary by many orders of magnitude as shown by barite scale formation and injectivity loss models for geothermal systems [1], emphasising the need for robust prediction models.</p><p>A relevant example case is the replacement of celestite (SrSO4) with barite (BaSO4), which was investigated for various barite supersaturations with flow-through experiments on the core-scale [2]. Three distinct cases were observed for supersaturations from high to low: (1) quick overgrowth and passivation of soluble celestite grains, (2) partial replacement of celestite with barite, (3) slow moving reaction front with complete mineral replacement. The authors presented heuristic approaches that include linking reactive surface area development to molar fractions to model the results. We provide a comprehensive, full-physics geochemical modelling approach using precipitation and dissolution kinetics as well as nucleation and crystal growth [3] for a more flexible representation of the problem. Additionally, the generation of a digital rock representation based on CT-scans of the granular sample is utilised to derive its inner surface area [4]. The experiments were modelled using core-scale reactive transport simulations. The three observed cases at varying supersaturations were reproduced with regard to evolution of sample rock composition and porosity.</p><p>In a next step, the characteristic values taken from the calibrated reactive transport models can be further integrated into the existing digital rock physics model [4], thus enabling the development of up-scaled relationships such as reactive surface area as a function of mineral fractions and porosity. The resulting models can then be applied to reservoir-scale simulations for various applications related to subsurface utilisation. </p><p>---</p><p>[1] Tranter, M., De Lucia, M., Wolfgramm, M., Kühn, M., 2020. Barite Scale Formation and Injectivity Loss Models for Geothermal Systems. Water 12, 3078. https://doi.org/10/ghntzk<br>[2] Poonoosamy, J., Klinkenberg, M., Deissmann, G., Brandt, F., Bosbach, D., Mäder, U., Kosakowski, G., 2020. Effects of solution supersaturation on barite precipitation in porous media and consequences on permeability: Experiments and modelling. Geochimica et Cosmochimica Acta 270, 43–60. https://doi.org/10/ghntxn<br>[3] Tranter, M., De Lucia, M., Kühn, M., 2021. Numerical investigation of barite scaling kinetics in fractures. Geothermics 91, 102027. https://doi.org/10/ghr89n<br>[4] Wetzel, M., Kempka, T., Kühn, M., 2020. Hydraulic and Mechanical Impacts of Pore Space Alterations within a Sandstone Quantified by a Flow Velocity-Dependent Precipitation Approach. Materials 13, 3100. https://doi.org/10/ghsp42</p>

Inorganic silicification of ancient carbonate rocks

ABSTRACT Mechanisms of inorganic silicification of early Precambrian (older than 750 Ma) carbonate rocks remain equivocal. A quantitative model is presented here that captures the essence of ancient inorganic silicification of the carbonate rocks and is based on the hypotheses that carbonate silicification, a volume-conservative replacive process, is driven by crystallization stress induced by the growth of the guest mineral. Results of the quantitative model for silicification of calcitic limestone and dolostone are compared and validated against available independent observations and are found to be geologically reasonable. The quantitative model suggests that silicification of carbonate rocks is dependent on the host-rock composition and that calcitic limestones will be readily silicified compared to dolostone and/or aragonitic limestone. Results also show that silicification rate of carbonate rocks—irrespective of their composition—increases with increase in silica supersaturation and reactive surface area. Porosity and permeability of the host rock also increases the silicification rate of the carbonate rocks. Results also predict that substantial volume of silica-saturated fluids is required for inorganic silicification of a one-meter cube of carbonate rock. The quantitative model presented here has its limitations and should not be viewed as a unique and truly realistic representation of the carbonate silicification mechanism. The quantitative model presented here is unable to explain the formation of porosity and subsequent volume reduction of the parent material during the replacement process as observed in replacement experiments. Also, the effect of pH on silicification of carbonate rocks cannot be quantitatively estimated in this study. The quantitative model presented here should be viewed as one of the possible mechanisms of carbonate silicification that has to be tested further with experimental data and by model refinement.

EDMed Inconel 718 using powder metallurgy (P/M) sintered electrode made with nano and micron sized powders

This work presents experimental data carried out for surface modification of Inconel 718 using WC/Cu composite powder metallurgy (P/M) electrodes made of nano and micron sized particles. Both machine and tool parameters were selected for study and experiments were planned as per Taguchi’s L18 mixed orthogonal array in order to find the influence of parameters on surface roughness (SR) and micro-hardness (MH). Peak current, particle size and pulse on time were found to be most significant on both SR and MH. High reactive surface area of nano particles made surface alloying greater than the other tool electrodes and has shown its influence positively on both SR and MH. The EDX analysis reveals the migration of WC and Cu elements and deposition of carbon and oxygen particles on the surface. The XRD spectrum confirms presence of carbides (WC, W2C, Fe5C2, Cr7C3, Fe7C3 and Fe3C), oxides (Fe3O4, WO3 and Cr3O) and other intermetallics at different machining conditions indicating the influence of Pulse on time (TON) and Peak current (IP) on discharge energies and in turn on the properties of machined surface. The carbides generated on the machined surface increased the hardness to 845HV without much sacrifice of the roughness of the machined surface. The range of roughness values obtained in the present investigation is 2.443 to 4.098µm.