Divergence error based pp-adaptive discontinuous Galerkin solution of time-domain Maxwell's equations

A $p$-adaptive discontinuous Galerkin time-domain method is developed to obtain high-order solutions to electromagnetic scattering problems. A novel feature of the proposed method is the use of divergence error to drive the $p$-adaptive method. The nature of divergence error is explored and that it is a direct consequence of the act of discretization is established. Its relation with relative truncation error is formed which enables the use of divergence error as an inexpensive proxy to truncation error. Divergence error is used as an indicator to dynamically identify and assign spatial operators of varying accuracy to substantial regions in the computational domain. This results in a reduced computational cost than a comparable discontinuous Galerkin time-domain solution using uniform degree piecewise polynomial bases throughout.Comment: 28 pages, 22 figure

Assessment of Pressure Based Solver in Resolving Complex Shock Wave Phenomenon

This study presents a critical assessment of a pressure-based solver (PBS) in resolving complex interactions of shocks, turbulent structures etc.. The canonical problem chosen to be resolved in this study is of mode staging in axisymmetric supersonic jet screech. The screech phenomenon exhibits staging behavior characterized by frequency and azimuthal structure changes at specific frequencies. The PBS simulations in the popular ANSYS Fluent software-suite were validated against numerical work and experimental measurements, and results were analyzed. Simulations are performed on supersonic jets which emits dual high frequency screech tones at particular Mach numbers. At lower end of these supersonic Mach numbers, the flow can involve vanishingly weak shock strengths which is routinely captured in experiments and by density based solvers in literature. The limitations of the pressure-based solver in resolving complex shock flow phenomena and predicting mode staging are highlighted at vanishingly weak Mach numbers, emphasizing the need for further investigation given the recent popularity of such solvers for all Mach numbers including in high-speed flow.Comment: 14th Asian Computational Fluid Dynamics Conference, 30th October - 02nd November, 2023, Bengalur

A Comparative Analysis of Application of Genetic Algorithm and Particle Swarm Optimization in Solving Traveling Tournament Problem (TTP)

Traveling Tournament Problem (TTP) has been a major area of research due to its huge application in developing smooth and healthy match schedules in a tournament. The primary objective of a similar problem is to minimize the travel distance for the participating teams. This would incur better quality of the tournament as the players would experience least travel; hence restore better energy level. Besides, there would be a great benefit to the tournament organizers from the economic point of view as well. A well constructed schedule, comprising of diverse combinations of the home and away matches in a round robin tournament would keep the fans more attracted, resulting in turnouts in a large number in the stadiums and a considerable amount of revenue generated from the match tickets. Hence, an optimal solution to the problem is necessary from all respects; although it becomes progressively harder to identify the optimal solution with increasing number of teams. In this work, we have described how to solve the problem using Genetic algorithm and particle swarm optimization

An Overview of the Genus Nardostachys

Nardostachys jatamansi, a medicinally important herb of Nepalese origin, has been used for centuries in the Ayurvedic and Unani systems of medicine. In combination with Marsilea minuta it is being used as an antistress and anticonvulsant drug and also finds use in the treatment of epilepsy. Recently, it has been reported that N. jatamansi, which plays an important role in protecting from cerebral ischemia and liver damage, is also used for the treatment of osteoporosis and hypercalcemia. The other member of the genus Nardostachys, N. chinensis, possesses antifungal and antimalarial properties. It is also used in the treatment of skin dysfunction. A short summary of the chemical constituents of the two species along with their physical and biological properties is reported

N-(4-Methylphenyl) Benzenepropanamide - the First Isolated Amide From the Genus Paederia

Investigation of the stem of Paederia foetida (Rubiaceae) resulted in the isolation and characterization of N-(4-methylphenyl)-benzopropanamide, which was hitherto unknown as a natural product This is the first report of an amide for the genus Paederia

Malabaricone-A Induces A Redox Imbalance That Mediates Apoptosis in U937 Cell Line

BACKGROUND: The 'two-faced' character of reactive oxygen species (ROS) plays an important role in cancer biology by acting both as secondary messengers in intracellular signaling cascades and sustaining the oncogenic phenotype of cancer cells, while on the other hand, it triggers an oxidative assault that causes a redox imbalance translating into an apoptotic cell death. PRINCIPAL FINDINGS: Using a tetrazolium [{3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl}-2H-tetrazolium] based cell viability assay, we evaluated the cytotoxicity of a plant derived diarylnonanoid, malabaricone-A on leukemic cell lines U937 and MOLT-3. This cytotoxicity hinged on its ability to cause a redox imbalance via its ability to increase ROS, measured by flow cytometry using 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate and by decreasing glutathione peroxidase activity. This redox imbalance mediated apoptosis was evident by an increase in cytosolic [Ca(2+)], externalization of phosphatidyl serine as also depolarization of the mitochondrial membrane potential as measured by flow cytometry. There was concomitant peroxidation of cardiolipin, release of free cytochrome c to cytosol along with activation of caspases 9, 8 and 3. This led to cleavage of the DNA repair enzyme, poly (ADP-ribose) polymerase that caused DNA damage as proved by labeling with 4',6-diamidino-2-phenylindole (DAPI); furthermore, terminal deoxy ribonucleotide transferase catalysed incorporation of deoxy uridine triphosphate confirmed DNA nicking and was accompanied by arrest of cell cycle progression. CONCLUSIONS: Taken together, compounds like MAL-A having pro-oxidant activity mediate their cytotoxicity in leukemic cells via induction of oxidative stress triggering a caspase dependent apoptosis

Ratio of neutrophilic CD64 and monocytic HLA-DR: a novel parameter in diagnosis and prognostication of neonatal sepsis

Objective: Approaches to monitoring of sepsis have traditionally relied upon the pro-inflammatory component of the sepsis response. This study evaluated the diagnostic and prognostic potential of the ratio of neutrophilic CD64 (nCD64) and monocytic HLA-DR (mHLA-DR) median fluorescence index in monitoring of neonatal sepsis. Methods: Blood from 100 neonates suspected of sepsis and 29 healthy controls was collected on clinical suspicion of sepsis, and the expression of nCD64, mHLA-DR was evaluated by Flow Cytometry; thereby, a derived parameter “Sepsis index,” SI = nCD64/mHLA-DR × 100 was estimated. Results: At day 1, sensitivity and specificity to detect sepsis using nCD64 was 73.01% and 89.18%, respectively, while for SI it was 73.01% and 72.22%, respectively. On Kaplan-Meier analysis, neonates with SI > cut-off showed a higher 30 day-mortality than those with low SI (P = 0.096). On multivariate analysis, the factor associated with mortality in our cohort was Apgar score ≤3, while SI showed a trend toward significance. Conclusions: At day1, nCD64 is useful for the diagnosis of neonatal sepsis whereas mHLA-DR is beneficial for monitoring patients at a later time point. The SI is a marker of moderate diagnostic sensitivity and supplements the current arsenal of laboratory investigations to detect neonatal sepsis. As a marker of prognosis, a high SI shows a trend towards greater mortality