Fibrosis and bone marrow: understanding causation and pathobiology.

Bone marrow fibrosis represents an important structural change in the marrow that interferes with some of its normal functions. The aetiopathogenesis of fibrosis is not well established except in its primary form. The present review consolidates current understanding of marrow fibrosis. We searched PubMed without time restriction using key words: bone marrow and fibrosis as the main stem against the terms: growth factors, cytokines and chemokines, morphology, megakaryocytes and platelets, myeloproliferative disorders, myelodysplastic syndrome, collagen biosynthesis, mesenchymal stem cells, vitamins and minerals and hormones, and mechanism of tissue fibrosis. Tissue marrow fibrosis-related papers were short listed and analysed for the review. It emerged that bone marrow fibrosis is the outcome of complex interactions between growth factors, cytokines, chemokines and hormones together with their facilitators and inhibitors. Fibrogenesis is initiated by mobilisation of special immunophenotypic subsets of mesenchymal stem cells in the marrow that transform into fibroblasts. Fibrogenic stimuli may arise from neoplastic haemopoietic or non-hematopoietic cells, as well as immune cells involved in infections and inflammatory conditions. Autoimmunity is involved in a small subset of patients with marrow fibrosis. Megakaryocytes and platelets are either directly involved or are important intermediaries in stimulating mesenchymal stem cells. MMPs, TIMPs, TGF-ß, PDGRF, and basic FGF and CRCXL4 chemokines are involved in these processes. Genetic and epigenetic changes underlie many of these conditions.

Sustainable Process for the Extraction of Potassium from Feldspar Using Eggshell Powder.

To recover potassium from feldspar, a biowaste, i.e., eggshell, was used. The chief composition of eggshells is calcite. As it is a rich source of Ca, hence it is used with HCl to produce calcium chloride. Feldspar is an aluminosilicate mineral that bears potassium in the interstitial sites. To unlock the potassium from the interstitial sites, it was roasted with calcium chloride prepared by mixing eggshell and hydrochloric acid. At the roasting temperature, CaCl2 melts and penetrates into the aluminosilicate matrix to replace K with Ca. Potassium ion released from the silicate matrix combines with chloride ions to form potassium chloride, which solubilized in water during the leaching process of the roasted feldspar. For elucidation of the mechanism of the roasting process, the shrinking core model was applied to the roast-leach data, and diffusion through the product layer was inferred as the rate-determining step. The order of the roasting process was found to be 2.158 and activation energy calculated to be 155.3 kJ/mol. Apart from potassium, sodium and excess calcium also got co-leached. To recover potassium from the leach liquor selectively, sodium perchlorate was added to precipitate potassium as KClO4. Further, potassium perchlorate was thermally decomposed to give fertilizer grade potassium chloride (purity: 99.81%).

Defluoridation behavior of nanostructured hydroxyapatite synthesized through an ultrasonic and microwave combined technique.

The absorption performance of a nano-structured hydroxyapatite produced from a combined ultrasonic and microwave technique was examined for the removal of fluoride from contaminated water. The effect of physical and chemical parameters such as initial pH, contact time, initial fluoride concentration and temperature were investigated. The results indicated that the equilibrium adsorption data followed both the Langmuir and Freundlich isotherms, with a maximum monolayer adsorption capacity of 5.5mg/g at 298K. In addition, the kinetic studies have shown that the fluoride adsorption data followed a pseudo-second order model and that the intra-particle diffusion process played a significant role in determining the rate. The thermodynamic analysis also established that the adsorption process was endothermic and spontaneous. The initial and final fluoride loaded nano-hydroxyapatite samples were characterized using FESEM, TEM, XRD, FTIR and XPS methods. The analysis revealed that structural changes to the adsorbent had taken place.