ABSTRACT
The power conversion efficiency (PCE) of a dye-sensitized solar cell (DSSC) device depends on its semiconductor characteristics. Titanium dioxide (TiO2) nanoparticles are a semiconductor material commonly used in the DSSC device whose characteristics depend on the synthesis process. There are many routes to synthesize TiO2, however, they typically involve hazardous approaches, which may cause risk to the environment. Green synthesis is an environmentally friendly alternative method using ecological solvents that eliminates toxic waste and reduces energy consumption. In this work, tropical almond (Terminalia catappa L.) was used as a natural capping agent in the green synthesis to control the growth of TiO2. In addition, graphene oxide (GO) was used as a dopant to increase the performance of DSSC device. The results are convincing, in which the addition of 0.0017 % GO doping in tropical almond extract mediated green synthesis of TiO2 improved the PCE from 0.85 % to 1.72 %. These results suggest that GO-modified TiO2 nanoparticles green synthesized using tropical almond extract have great potential in the fabrication of DSSC devices with good PCE, low cost, and low environmental impact.
ABSTRACT
Rapid technological developments for the efficient generation of footprint-free induced pluripotent stem cells (iPSC) enabled the creation of patient-specific iPSC for downstream applications in drug discovery and regenerative medicine. However, the large number of iPSCs, generated from diverse genetic backgrounds using various methods and culture conditions, created a steep challenge for rapid characterization and a demand for standardized methods. Current methods rely on a combination of in vitro and in vivo cellular analyses based on the expression of markers of self-renewal and the ability of the cells to differentiate into cell types representative of the three germ layers as a confirmation of functional pluripotency. These methods, though informative and extensively used, are not ideal for parallel analyses of large numbers of samples and hence not amenable to high-throughput environments. Recently, genetic and epigenetic expression signatures were used to define and confirm cell states, thus providing a surrogate molecular assay that can potentially replace complex in vivo cellular assays such as teratoma formation. In this chapter, we describe a molecular assay for rapid characterization and standardization of pluripotent stem cells. The TaqMan(®) hPSC Scorecard™ Panel is a comprehensive gene expression real-time PCR assay that consists of 94 individual q-PCR assays comprised of a combination of control, housekeeping, self-renewal, and lineage-specific genes. The resulting expression data set is analyzed using cloud-based analysis software that compares the expression pattern against a reference standard composed of multiple functionally validated ESC and iPSC lines. This system was successfully used to test several ESC and iPSC lines in their undifferentiated states to confirm their signatures of self renewal, as well as their terminally differentiates states, via spontaneous differentiation and directed differentiation into specific lineages, to determine the lines' differentiation potential. This genetic analysis tool, together with the flexibility to utilize varying sample inputs and preparation methods, provides a rapid method to confirm functional pluripotency of ESCs and iPSCs.
Subject(s)
Pluripotent Stem Cells/cytology , Real-Time Polymerase Chain Reaction/methods , Animals , Cell Differentiation , Cells, Cultured , Embryoid Bodies/cytology , Feeder Cells/cytology , Humans , Mice , SoftwareABSTRACT
Degradation mechanisms such as lithium plating, growth of the passivated surface film layer on the electrodes and loss of both recyclable lithium ions and electrode material adversely affect the longevity of the lithium ion battery. The anode electrode is very vulnerable to these degradation mechanisms. In this paper, the most common aging mechanisms occurring at the anode during the operation of the lithium battery, as well as some approaches for minimizing the degradation are reviewed.
ABSTRACT
Austenitic stainless steels, widely used in food processing, undergo microstructural changes during welding, resulting in three distinctive zones: weld metal, heat-affected zone, and base metal. This research was conducted to determine the attachment of Listeria monocytogenes in these three zones before and after exposure to a corrosive environment. All experiments were done with tungsten inert gas welding of type 304 stainless steel. The four welding treatments were large or small beads with high or low heat. After welding, all surfaces were polished to an equivalent surface finish. A 10-microl droplet of an L. monocytogenes suspension was placed on the test surfaces. After 3 h at 23 degrees C, the surfaces were washed and prepared for scanning electron microscopy, which was used to determine attachment of L. monocytogenes by counting cells remaining on each test surface. In general, bacteria were randomly distributed on each surface type. However, differences in surface area of inoculum due to differences in interfacial energy (as manifested by the contact angle) were apparent and required normalization of bacterial count data. There were no differences (P > 0.05) in numbers of bacteria on the three surface zones. However, after exposure to the corrosive medium, numbers of bacteria on the three zones were higher (P < 0.05) than those on the corresponding zones of noncorroded surfaces. For the corroded surfaces, bacterial counts on the base metal were lower (P < 0.05) than those on heat-affected and weld zones.
