North Eastern Hill University

About: North Eastern Hill University is a education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topics: Population & Catalysis. The organization has 2318 authors who have published 4476 publications receiving 48894 citations.

Multi-species Cuckoo Search Algorithm for Global Optimization

Abstract: Many optimization problems in science and engineering are highly nonlinear and thus require sophisticated optimization techniques to solve. Traditional techniques such as gradient-based algorithms are mostly local search methods and often struggle to cope with such challenging optimization problems. Recent trends tend to use nature-inspired optimization algorithms. The standard cuckoo search (CS) is an optimization algorithm based on a single cuckoo species and a single host species. This work extends the standard CS by using the successful features of the cuckoo-host co-evolution with multiple interacting species. The proposed multi-species cuckoo search (MSCS) intends to mimic the co-evolution among multiple cuckoo species that compete for the survival of the fittest. The solution vectors are encoded as position vectors. The proposed algorithm is then validated by 15 benchmark functions as well as five nonlinear, multimodal case studies in practical applications. Simulation results suggest that the proposed algorithm can be effective for finding optimal solutions and all optimal solutions are achievable in the tested cases. The results for the test benchmarks are also compared with those obtained by other methods such as the standard cuckoo search and genetic algorithm. The comparison has demonstrated the efficiency of the present algorithm. Based on numerical experiments and case studies, we can conclude that the proposed algorithm can be more efficient in most cases. Therefore, the proposed approach can be a very effective tool for solving nonlinear global optimization problems.

Extended Phase Space Analysis of Interacting Dark Energy Models in Loop Quantum Cosmology

Abstract: The present work deals with the dynamical system investigation of interacting dark energy models (quintessence and phantom) in the framework of loop quantum cosmology by taking into account a broad class of self-interacting scalar field potentials. The main reason for studying potentials beyond the exponential type is to obtain additional critical points which can yield more interesting cosmological solutions. The stability of critical points and the asymptotic behavior of the phase space are analyzed using dynamical system tools and numerical techniques. We study two classes of interacting dark energy models and consider two specific potentials as examples: the hyperbolic potential and the inverse power-law potential. We find a rich and interesting phenomenology, including the avoidance of big rip singularities due to loop quantum effects, smooth and nonlinear transitions from matter domination to dark energy domination, and finite periods of phantom domination with dynamical crossing of the phantom barrier.

Chlorophyllin supplementation modulates hyperglycemia-induced oxidative stress and apoptosis in liver of streptozotocin-administered mice.

Abstract: Chlorophyllin is a water-soluble mixture of sodium-copper salts of chlorophyll with antioxidant and antimutagen properties. In this study, an attempt has been made to evaluate the effect of chlorophyllin on hyperglycemia-induced oxidative stress and apoptosis in liver of streptozotocin (STZ)-administered mice. In STZ-induced diabetes, two causative factors for pancreatic β-cell deaths are DNA alkylation and profound reactive oxygen species (ROS) generation. In this study, chlorophyllin treatment was found to be able to modulate oxidative stress and apoptosis in liver of diabetic mice. Diabetic mice exhibited a significant reduction of ROS, malondialdehyde (MDA), and protein carbonyl levels upon treatment with the chlorophyllin. However, antioxidant enzymes, such as copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), and catalase (CAT) showed enhanced activity as well as expression in chlorophyllin-administered diabetic mice. The hepatoprotective effect of chlorophyllin was confirmed from the decreased activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). The histological and ultrastructural studies revealed the ability of chlorophyllin to restore morphological and cellular alterations as observed in STZ-induced diabetic mice. The effect of chlorophyllin on apoptosis showed the downregulation of cysteine-dependent aspartate-specific protease (caspase) 3 and caspase 9, whereas upregulation of B-cell lymphoma-2 (Bcl-2) protein, and the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) assay demonstrated a few apoptotic cells. In conclusion, it can be stated that chlorophyllin treatment can exert hepatoprotective effect via modulating hyperglycemia-induced oxidative stress and apoptosis in STZ-administered diabetic mice. © 2018 BioFactors, 44(5):418-430, 2018.