Boundary and thermal non-equilibrium effects on the onset of Darcy–Brinkman convection in a porous layer

A local thermal non-equilibrium model for the temperature representing the solid and fluid phases separately is used to study the onset of free convection in a sparsely packed porous layer using the Brinkman-extended Darcy model. The lower boundary of the porous layer is considered to be rigid and isothermal, while the upper isothermal boundary is assumed to be either rigid or free. The Galerkin method is used to obtain the eigenvalue equation, which is then solved numerically. The effects of thermal non-equilibrium and other physical parameters on the onset of convection are analyzed and compared for two types velocity boundary conditions considered. Besides, some known results available in the literature are compared with those obtained from the present study and good agreement is found.     

Semantic Analysis Techniques using Twitter Datasets on Big Data: Comparative Analysis Study

This paper conducts a comprehensive review of various word and sentence semantic similarity techniques proposed in the literature. Corpus-based, Knowledge-based, and Feature-based are categorized under word semantic similarity techniques. String and set-based, Word Order-based Similarity, POSbased, Syntactic dependency-based are categorized as sentence semantic similarity techniques. Using these techniques, we propose a model for computing the overall accuracy of the twitter dataset. The proposed model has been tested on the following four measures: Atish’s measure, Li’s measure, Mihalcea’s measure with path similarity, and Mihalcea’s measure with Wu and Palmer’s (WuP) similarity. Finally, we evaluate the proposed method on three real-world twitter datasets. The proposed model based on Atish’s measure seems to offer good results in all datasets when compared with the proposed model based on other sentence similarity measures.     

sp3-Rich Glycyrrhetinic Acid Analogues Using Late-Stage Functionalization as Potential Breast Tumor Regressing Agents

Late-stage functionalization (LSF) aids drug discovery efforts by introducing functional groups onto C−H bonds on pre-existing skeletons. We adopted the LSF strategy to synthesize analogues of the abundantly available triterpenoid, glycyrrhetinic acid (GA), by introducing aryl groups in the A-ring, expanding the A-ring and selectively activating one methyl group of the gem-dimethyl groups. Intriguingly, two compounds were found to preferentially accumulate in the mitochondrial compartment of MDA-MB-231 breast cancer cells, to cause depolarization of mitochondrial membrane potential and to induce antiproliferative and anti-invasive effects through enhanced mitochondrial superoxide production with parallel depletion of GSH levels. Furthermore, intraperitoneal administration of these two compounds, in comparison with GA, greatly regressed breast tumor growth and metastasis in a SCID mouse model bearing labeled MDA-MB-231 cells.     

Brinkman ferromagnetic convection in a porous layer: Effect of MFD viscosity and magnetic boundaries

In the present study, the effect of magnetic field dependent (MFD) viscosity and different types of magnetic boundaries on the onset of ferromagnetic convection in a horizontal layer of Brinkman porous medium is investigated numerically using the Galerkin method. The simultaneous and isolation presence of buoyancy and magnetic forces on the stability characteristics of the system are emphasized. The study reveals that the linear stability of the system depends significantly on the types of magnetic boundaries. The rigid-paramagnetic boundaries are found to be preferred to the ferromagnetic ones in suppressing ferromagnetic convection. Besides, the system is more stable when the magnetic forces alone are present. In addition, increasing MFD viscosity parameter λ and decreasing magnetic number M ₁ and nonlinearity of fluid magnetization parameter M ₃ is to inhibit the onset of ferromagnetic convection in a porous medium. The critical wave number is found to be independent of λ, but increasing M ₁ and χ as well as decreasing M ₃ is to reduce the size of convection cells. At higher values of M ₃ , the critical Rayleigh number and the corresponding wave number coincide for different magnetic boundaries.