Contribution of bacterial cells as nucleation centers in microbiologically induced CaCO3 precipitation—A mathematical modeling approach

The microbiologically induced calcite precipitation (MICP) has been extensively studied for geotechnical engineering through simultaneous action of natural phenomena and engineering processes. The focus of bacterial contribution to the MICP has been directed to calcium carbonate productivity, while the additional bacterial role as a crystal nucleation center was not explained especially from a mathematical prediction modeling point of view. Therefore, this study provides explanations and a mathematical modeling approach of bacterial influence on the MICP induced by newly-isolated ureolytic Bacillus strains and Sporosarcina pasteurii DSM 33. Using the obtained results of low-cost, rapid, and simple assays, artificial neural network modeling was applied for cell surface predispositions, pH changes as well as calcium-involved function in biofilm formation during the MICP, for the first time. Based on the obtained contribution of the alkalophilic/alkaloresistant bacteria, calcite precipitation can be significantly directed by the presence, of ureolytic bacterial cells as nucleation centers during CaCO₃ precipitation as well as their morphology, surface characteristics, potential to form a biofilm, and/or generate pH changes.     

Aluminium hydroxide stabilised MnFe2O4 and Fe3O4 nanoparticles as dual-modality contrasts agent for MRI and PET imaging

Magnetic nanoparticles (NPs) MnFe₂O₄ and Fe₃O₄ were stabilised by depositing an Al(OH)₃ layer via a hydrolysis process. The particles displayed excellent colloidal stability in water and a high affinity to [¹⁸F]-fluoride and bisphosphonate groups. A high radiolabeling efficiency, 97% for ¹⁸F-fluoride and 100% for ⁶⁴Cu-bisphosphonate conjugate, was achieved by simply incubating NPs with radioactivity solution at room temperature for 5 min. The properties of particles were strongly dependant on the thickness and hardness of the Al(OH)₃ layer which could in turn be controlled by the hydrolysis method. The application of these Al(OH)₃ coated magnetic NPs in molecular imaging has been further explored. The results demonstrated that these NPs are potential candidates as dual modal probes for MR and PET. In vivo PET imaging showed a slow release of ¹⁸F from NPs, but no sign of efflux of ⁶⁴Cu.     

Multi-ligament instability after early dislocation of a primary total knee replacement — Case report

Peripheral nerve blocks have found increased popularity in providing prolonged post-operative analgesia following total knee replacement surgery. They generally provide effective analgesia with fewer complications than epidurals.This report describes an acute low-energy knee dislocation after a well balanced, fixed bearing, cruciate-retaining primary total knee replacement performed under a spinal anaesthetic with combined complimentary femoral and sciatic nerve blocks. The dislocation was not accompanied by neurovascular compromise. Due to the subsequent instability and injury to both collaterals, the posterior cruciate ligament and posterolateral corner structures, the knee was treated with a rotating-hinge revision total knee replacement.The dislocation occurred whilst the peripheral nerve blocks (PNB) were still working. We review our incidence of PNB related complications and conclude that PNB remain a safe and effective analgesia for total knee replacements. However, we advocate that ward staff and patients should be sufficiently educated to ensure that unaided post-operative mobilisation is prevented until such a time that patients have regained complete voluntary muscle control.