Raman Spectroscopic Characterization of Hepatic Differentiation of Mesenchymal Stem Cells

Background and Aims: Mesenchymal stem cells (MSCs) are a preferred cell source for the generation of hepatocyte-like cells in regenerative medicine. They can be isolated from different sources, including adipose tissues. The Raman spectroscopy approach was evaluated for quick and efficient identification of MSCs differentiation status and a broader perspective on cell differentiation. Materials and Methods: The human adipose-derived mesenchymal stem cells (hASCs) were differentiated toward hepatocyte-like cells using a well-established method. The cells were cultured on fluorescence-free quartz discs, and the efficiency of differentiation was examined using molecular and biochemical methods. The Raman spectra were recorded at days 1, 7, 14, and 21 of differentiation, and HepG2 was used as a positive control. Results: The changes in Raman spectra were detected during the sequential stages of differentiation, and the pattern of peaks on the last day of differentiation was remarkably similar to the positive control (HepG2). Conclusion: Raman spectroscopy showed considerable potential to characterize hepatic differentiation.

Mineralogical, Physico-chemical and Geochemical Characterization of Three Kaolinitic Clays (Ne Algeria): Comparative Study

Forteen clay samples collected from three kaolin deposits (Tamazert, Hadj Ali and Chekfa; NE Algeria) are characterized by several techniques in order to compares them to somes kaolins used in industry especially that used in ceramics. All the samples were investigated by X-ray diffraction, Infrared absorption spectroscopy, thermal analysis (TG), plasticity, environmental scanning electron microscopy and chemical major elements analysis. The bulk mineralogical composition of all clays samples is dominated by kaolinite (21-75%), illite/ muscovite (33-76%) and quartz (7-21%). K-feldspar and plagioclase are only present in Chekfa and Hadj Ali clays with small amounts. Clay fraction (< 2µm) dominated by kaolinite and illite (98%). Chlorite and smectite are present in some samples of Chekfa and Hadj Ali clays with insignificant amount (˂1%). The particles-size distribution of all samples showed the abundance of sandy silt fraction (28-63%) and silty sand (39-64%) with moderate clayey fraction (2-7%). The chemical composition showed variable amounts of SiO2 (59-68%), Al2O3 (18-39%), Fe2O3 (.26-1.38%) and TiO2 (0.34-0.69%) in accordance with the free quartz in all studied samples. Plasticity-index (7.5-7.9%), Specific surface (28-47m2) and Cation exchange (5-11meq/100g) values are moderate in all samples. Given these properties, these clays may be suitable in bricks and ceramic product.

Graphene oxide-Au nano particle coated quartz crystal microbalance biosensor for the real time analysis of carcinoembryonic antigen

A label-free quartz crystal microbalance (QCM) biosensor was developed for the selective and real-time estimation of carcinoembryonic antigen (CEA) through the present study.

A New Method to Inhibit Bed Agglomeration Problems in Fluidized Bed Boilers

Fluidized bed combustion (FBC) technology was commercialized in the 70s. Both bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) technology are capable of handling a wide variety of solid fuels. Natural sand is typically used as the fluidizing material. However, the properties and behavior of some solid fuel ash may limit the use of these fuels due to bed agglomeration problems. Natural sand contains several minerals, typically mainly consisting of 20–50 wt.-% of plagioclase (NaAlSi3O8 + CaAlSi3O8), 10–30 wt.-% of potash feldspar (KAlSi3O8), and 25–100 wt.-% of quartz (SiO2). Biomass based fuels contain high amounts of alkali. Ash high in alkali may react with the free quartz of the natural sand, producing an alkali silicate mixture with low melting point. This mixture may act as an adhesive between fluidized bed particles and may, in the worst-case, result in serious fluidization problems. This problem can be avoided by using AGGLOSTOP™ quartz-free bed material. Four different bed materials were tested in a 15 kW laboratory-scale FBC test rig with plywood residue, which is known to cause severe fluidization problems in FB boilers. Two of the tested bed materials were quartz-free. When quartz-free bed materials were used, no signs of bed agglomeration were observed. The other two bed materials containing free quartz caused total defluidization at a temperature of around 750°C after about half an hour of operation. The concept of using AGGLOSTOP™ quartz-free bed material with high alkali fuels has been successfully applied in two industrial scale BFB boilers (15 and 74 MWth). The use of AGGLOSTOP™ fluidized bed material enables energy production in FB boilers based on high alkali fuels, which were earlier impossible to utilize due severe bed agglomeration problems. This paper focuses on the bed agglomeration phenomenon by discussing the results from laboratory and industrial-scale boilers and presents a new solution to extend the use of high alkali fuels in FB boilers.