Ultrasonication: An effective pre-treatment method for extracting lipid from Salvinia molesta for biodiesel production

Biodiesel is considered as one of the promising alternative fuels for diesel engines due its renewability and environment friendly nature. As the process of lipid extraction from the biomass consumes about 90% of the total energy spent for biodiesel production, an efficient and economic method is very important. The amount of lipid extracted from the biomass could be increased if it is pre-treated before the extraction process. This work was an attempt to compare the various pre-treatment methods before extracting lipids from dried Salvinia molesta (aquatic weed), such as autoclaving, microwaving, ultrasonication, sand, and glass grinding. After each pre-treatment method, Bligh and Dyer's method was used to measure the total lipid content in percentage dry weight (% dwt), which was then compared with the untreated S. molesta. It was found experimentally that the lipid yield was 19.97% dwt for ultrasonication > 16.60% dwt for microwaving > 16.46% dwt for glass grinding >16.26% dwt for sand grindin, > 15.72% dwt for autoclaving > 15.36% dwt for untreated. The one-way ANOVA with Tukey's test was then used to validate the experimental results and showed that ultrasonication method of pre-treatment was the most efficient and had resulted in the highest lipid yield among all the methods used which was followed by the microwaving method

Neuropilin-2 Mediated β-Catenin Signaling and Survival in Human Gastro-Intestinal Cancer Cell Lines

NRP-2 is a high-affinity kinase-deficient receptor for ligands belonging to the class 3 semaphorin and vascular endothelial growth factor families. NRP-2 has been detected on the surface of several types of human cancer cells, but its expression and function in gastrointestinal (GI) cancer cells remains to be determined. We sought to determine the function of NRP-2 in mediating downstream signals regulating the growth and survival of human gastrointestinal cancer cells. In human gastric cancer specimens, NRP-2 expression was detected in tumor tissues but not in adjacent normal mucosa. In CNDT 2.5 cells, shRNA mediated knockdown NRP-2 expression led to decreased migration and invasion in vitro (p<0.01). Focused gene-array analysis demonstrated that loss of NRP-2 reduced the expression of a critical metastasis mediator gene, S100A4. Steady-state levels and function of β-catenin, a known regulator of S100A4, were also decreased in the shNRP-2 clones. Furthermore, knockdown of NRP-2 sensitized CNDT 2.5 cells in vitro to 5FU toxicity. This effect was associated with activation of caspases 3 and 7, cleavage of PARP, and downregulation of Bcl-2. In vivo growth of CNDT 2.5 cells in the livers of nude mice was significantly decreased in the shNRP-2 group (p<0.05). Intraperitoneal administration of NRP-2 siRNA-DOPC decreased the tumor burden in mice (p = 0.01). Collectively, our results demonstrate that tumor cell–derived NRP-2 mediates critical survival signaling in gastrointestinal cancer cells

Effect of surface radiation on conjugate natural convection in a horizontal annulus driven by inner heat generating solid cylinder

This paper reports a numerical study of the laminar conjugate natural convection heat transfer with and without the interaction of the surface radiation in a horizontal cylindrical annulus formed between an inner heat generating solid circular cylinder and an outer isothermal circular boundary. Numerical solutions are obtained by solving the governing equations with a pressure correction method on a collocated (non-staggered) mesh. Steady-state results are presented for the flow and temperature distributions and Nusselt numbers for the heat generation based Grashof number ranging from 10(7) to 10(10), solid-to-fluid thermal conductivity ratios of 1, 5, 10, 50 and 100, radius ratios of 0.226 and 0.452 and surface emissivities of 0-0.8 with air as the working medium. It is observed that surface radiation reduces the convective heat transfer in the annulus compared to the pure natural convection case and enhances the overall Nusselt number

Laminar conjugate natural convection in horizontal annuli

A numerical study of two-dimensional conjugate natural convection in a horizontal cylindrical annulus formed between an inner heat generating solid square cylinder and an outer isothermal circular boundary is performed. The two orientations considered for the inner solid square cylinder are the square-on-side (SOS) and the square-on-edge (SOE). A cylindrical annulus with an inner solid circular cylinder (CC) of equivalent heat generation is also studied for the purpose of comparison. The flow equations cast in vorticity-stream function form and the energy equations are solved using numerical methods. The steady state results show that the flow in the annulus is characterized by double or quadruple vortex patterns. Of the dimensionless maximum solid temperature, average solid temperature and average inner boundary temperature, the first two are much sensitive to solid-to-fluid thermal conductivity ratio. The dependence of the average Nusselt number on the average inner boundary temperature based Grashof number is found to be in good agreement with the heat transfer data computed for differentially heated annuli with isothermal boundaries, within the parametric space covered. Correlations as functions of Grashof number are developed for the estimation of various quantities of interest for different configurations, aspect ratios and thermal conductivity ratios. The results are expected to be useful in the design of thermal systems such as the spent nuclear fuel casks and underground transmission cables

Hypothetical schema for NRP-2-mediated activation of β-catenin signaling in gastrointestinal cancer cells.

<p>Left: In a GI cancer cell, increased inactive GSK3β inhibits destruction complex function, leading to stabilization of β-catenin that is free to translocate to the nucleus and activate transcription of target genes. Right: In a GI cancer cell with NRP-2 knockdown, the active destruction complex phosphorylates β-catenin and targets it for proteasome-mediated degradation, resulting in decreased activation of downstream target genes.</p