72 research outputs found

    Guided Wave Resonant Optical Structures and LED Micro Resonators for Biosensing Applications

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    Integrated opto-electronic and nanophotonic devices for sensing application in the fields of medicine, microbiology, environmental, safety and defense have attracted considerable attention due to their potential for achieving greater compactness, shorter response times and higher sensitivities as compared to non-optical sensing systems. Optical cavity resonant devices such as Fabry--Perot interferometers have been extensively used in lasing applications and optical sensing has been accomplished through many similar technologies.;Fiber optic and planar waveguide based resonant devices which use evanescent waves for detection of refractive index changes are one of the most widely used approaches for photonic sensors. In this work we investigate the simulations, fabrication and characterization of resonant optical cavity devices for sensing applications. Morphology Dependent Resonances (MDRs) of planar, micro-spherical and micro-cylindrical cavities were reviewed for resonance line widths, spacing between modes, and density of resonances and experimental observations of internal and external field distributions. We focus on planar thin film stacked resonant waveguide geometries, microsphere-waveguide coupled resonances, cylindrical Gallium Nitride (GaN) microdisks for passive detection of Whispering Gallery Modes (WGMs) and electrically pumped active Resonant Cavity (RC) LED disk geometries for Vertical Cavity Modes (VCMs) as structures of interest.;Advances in stacked thin film coupled waveguide sensors enhance the selectivity and sensitivity by measuring the changes of the resonant optical modes and provide an integrated platform for label-free molecular detection. The effective surface loading detection sensitivity of the planar coupled alumina waveguide transducer was determined to be 20 pg/mm2 with a bulk index sensitivity of 5.6x10-4 Refractive Index Units (RIU) for aqueous sucrose solutions. For circular geometry based resonators, as the physical device size approaches the wavelength of light the MDRs are enhanced by retaining longer photon path length times and enhancing detection due to its high Q factors. Circular micro-cavities not only modify the optical resonances but also distribute the resonant frequencies as compared to a planar macro-cavity. The waveguide-coupled microspheres were experimentally detected to have a minimum surface coverage limit of 0.192%. Passive WGMs in GaN micro-disks showed a variation in mode spacing of 3nm to 7nm (lambda2/2piRn) as disk radius was reduced from 4.5microm to 2microm. Micro-cylindrical Distributed Bragg Reflector (DBR) RCLEDs were designed for layer thicknesses and Multi Quantum Well (MQW) placement to enhance VCMs and LED emission output. Experimental and simulated LED spectral minima matched at 432 nm and 451 nm confirming VCMs related to (lambda/2) cavity resonances

    Two dimensional effects of laser interacting with magnetized plasma

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    Recent advancements in low-frequency short-pulse CO2CO_2 lasers and the production of strong magnetic fields have made experimental studies on laser interactions with magnetized plasma a near-future possibility. Therefore, theoretical and numerical simulation studies have been pursued lately in this direction [A. Das, Review of Modern Plasma Physics 4, 1 (2020)] illustrating a host of novel phenomena related to laser energy absorption [Vashistha et al., New Journal of Physics, 22(6):063023 (2020); Goswami et al., Plasma Physics and Controlled Fusion 63, 115003 (2021)], harmonic generation [Maity et al., Journal of Plasma Physics, 87(5) (2021)], etc. However, most of these studies have been carried out in one-dimensional geometry with the laser having infinite transverse extent, and the plasma target was considered cold. This manuscript explores the manifestation of the 2-D and thermal effects on the problem of a laser interacting with magnetized plasma. As expected, additional transverse ponderomotive force is shown to be operative. A finite temperature of the target, along with transverse density stratification generates, leads to diamagnetic drift for the two plasma species. The imbalance of this drift between the two species can be an additional effect leading to an enhancement of laser energy absorption. The Particle - In - Cell (PIC) simulations with the OSIRIS4.0 platform is used to explore these features.Comment: 15 pages, 12 figures, 12 equation

    Harmonic generation in magnetized plasma for Electromagnetic wave propagating parallel to external magnetic field

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    The harmonic generation has always been of fundamental interest in studying the nonlinear nature of any physical system. In the present study, Particle - In - Cell (PIC) simulations have been carried out to explore the harmonic generation of Electromagnetic waves in a magnetized plasma. The EM wave propagation is chosen to be parallel to the applied external magnetic field. The simulations show the excitation of odd higher harmonics of RCP (Right circularly polarized) and LCP (Left circularly polarized) when the incident wave is linearly polarised. The harmonic generation is maximum when the incident EM wave frequency matches the electron cyclotron frequency. When the incident EM wave has a circular polarization, no harmonics get excited. A theoretical understanding of these observations has also been provided. The studies thus show that by appropriately tailoring of plasma parameters EM waves of higher frequencies and desired nature of circular polarization can be generated.Comment: 25 pages, 15 figure

    Ion heating in Laser interacting with magnetized plasma

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    The ion heating mechanism in the context of laser interacting with plasma immersed in a strong magnetic field is studied. The magnetic field is chosen to be strong for laser electromagnetic field propagation inside the plasma to be governed by the magnetized dispersion relation. Both X and RL mode configurations have been studied in detail using Particle - In - Cell (PIC) simulations. It is shown that the energy absorption process is governed by a resonant mechanism wherein the laser frequency matches with an underlying mode in the plasma. For X and RL mode configurations, these correspond to lower hybrid and ion cyclotron resonance, respectively. The absorption, however, is found to be most efficient at frequencies close to but not exactly matching with the resonance frequency. An understanding of the same has been provided. The role of laser polarization has been studied in detail.Comment: 21 pages, 17 figure

    ADOPTING INNOVATIVE METHOD AND COMPARATIVE EVALUATION OF SWETHA PARPATI MENTIONED IN AYURVEDIC LITERATURE

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    In Ayurveda, the study of the therapeutic uses and effects of drugs means Pharmaco-therapeutic is described under the branch of Rasashastra which mainly incorporates inorganic, herbo-mineral and metallic pharmaceutical preparations namely Khalviya Rasayana, Parpati Rasayana, Pottali Rasayana and Kupipakwa Rasayana. This article aims for the comparative assessment of Swethaparpati coming under Parpatikalpa mentioned as per reference of Sidhayogasangraha, AFI with another reference of Rasodharatantra. According to the first two references the ingredients used for the preparation are Suryakshara, Sphatika and Navasadara and as per the third reference ingredients like Tankana and Karpura are added. Here a detailed review of literature has been collected regarding the potential of the above mentioned individual ingredients along with the recent research updates regarding individual ingredients used in the production of Swetha Parpati according to both the references it also incorporate research updates on the formulation Swetha Parpati. This article also aims pharmaceutical standardization of standard method adopted in process of production of Swethaparpati with the alteration made from the usual method adopted in preparation of Parpati Kalpana that will help for developing new improved SOP regarding the formulation. This paper also aims in projecting the improved therapeutic value which could be generated by addition of new ingredients mentioned as per reference of Rasodharatantra

    A CRITICAL AYURVEDIC LITERARY REVIEW OF THE PLANT PANASA (ARTOCARPUS HETEROPHYLLUS LAM.)

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    Panasa (Artocarpus heterophyllus Lam), the well known jackfruit tree is widely distributed all over the world. It is a treasure trove of various ethnomedical uses which are yet to be proven scientifically. Its fruit is very delicious and its leaves, root, latex, seed and wood are reported to have many medicinal properties. Though the plant is renowned for its nutritive values, the useful parts of the plant with rich medicinal values are less utilized for medicinal purposes. The plant is well described in Ayurvedic classics where prime importance has been given to its fruit whereas least references are available concerned to its other useful parts especially the leaf. This forms the literature gap concerned with this drug that hinders its further clinical researches. A compiled review of the classical literature of Panasa is not yet available as a ready reference. Hence it is a herculean task for the researcher to compile the literature which is scattered in various classical books of different era. In this work focus has been made to compile the literature of the plant Panasa (Artocarpus heterophyllus Lam) from the Ayurvedic classics. As this work provides the literature of this plant under a single roof it will be helpful for the scholars in future research works

    Exploring the antecedents of AI adoption for effective HRM practices in the Indian pharmaceutical sector

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    Purpose: The aim of this research is to investigate the factors that facilitate the adoption of artificial intelligence (AI) in order to establish effective human resource management (HRM) practices within the Indian pharmaceutical sector.Design/methodology/approach: A model explaining the antecedents of AI adoption for building effective HRM practices in the Indian pharmaceutical sector is proposed in this study. The proposed model is based on task-technology fit theory. To test the model, a two-step procedure, known as partial least squares structural equational modeling (PLS-SEM), was used. To collect data, 160 HRM employees from pharmacy firms from pan India were approached. Only senior and specialized HRM positions were sought.Findings: An examination of the relevant literature reveals factors such as how prepared an organization is, how people perceive the benefits, and how technological readiness influences AI adoption. As a result, HR systems may become more efficient. The PLS-SEM data support all the mediation hypothesized by proving both full and partial mediation, demonstrating the accuracy of the proposed model.Originality: There has been little prior research on the topic; this study adds a great deal to our understanding of what motivates human resource departments to adopt AI in the pharmaceutical companies of India. Furthermore, AI-related recommendations are made available to HRM based on the results of a statistical analysis

    Docosahexaenoic Acid Increases the Potency of Soluble Epoxide Hydrolase Inhibitor in Alleviating Streptozotocin-Induced Alzheimer’s Disease-Like Complications of Diabetes

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    Diabetes is a risk factor for Alzheimer’s disease and it is associated with significant memory loss. In the present study, we hypothesized that the soluble epoxide hydrolase (sEH) inhibitor N-[1-(1-oxopropyl)-4-piperidinyl]-N’-[4-(trifluoromethoxy)phenyl)-urea (also known as TPPU) could alleviate diabetes-aggravated Alzheimer’s disease-like symptoms by improving memory and cognition, and reducing the oxidative stress and inflammation associated with this condition. Also, we evaluated the effect of edaravone, an antioxidant on diabetes-induced Alzheimer’s-like complications and the additive effect of docosahexaenoic acid (DHA) on the efficacy of TPPU. Diabetes was induced in male Sprague-Dawley rats by intraperitoneally administering streptozotocin (STZ). Six weeks after induction of diabetes, animals were either treated with vehicle, edaravone (3 or 10 mg/kg), TPPU (1 mg/kg) or TPPU (1 mg/kg) + DHA (100 mg/kg) for 2 weeks. The results demonstrate that the treatments increased the memory response of diabetic rats, in comparison to untreated diabetic rats. Indeed, DHA + TPPU were more effective than TPPU alone in reducing the symptoms monitored. All drug treatments reduced oxidative stress and minimized inflammation in the brain of diabetic rats. Expression of the amyloid precursor protein (APP) was increased in the brain of diabetic rats. Treatment with edaravone (10 mg/kg), TPPU or TPPU + DHA minimized the level of APP. The activity of acetylcholinesterase (AChE) which metabolizes acetylcholine was increased in the brain of diabetic rats. All the treatments except edaravone (3 mg/kg) were effective in decreasing the activity of AChE and TPPU + DHA was more efficacious than TPPU alone. Intriguingly, the histological changes in hippocampus after treatment with TPPU + DHA showed significant protection of neurons against STZ-induced neuronal damage. Overall, we found that DHA improved the efficacy of TPPU in increasing neuronal survival and memory, decreasing oxidative stress and inflammation possibly by stabilizing anti-inflammatory and neuroprotective epoxides of DHA. In the future, further evaluating the detailed mechanisms of action of sEH inhibitor and DHA could help to develop a strategy for the management of Alzheimer’s-like complications in diabetes

    The state of Fortran

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    A community of developers has formed to modernize the Fortran ecosystem. In this article, we describe the high-level features of Fortran that continue to make it a good choice for scientists and engineers in the 21st century. Ongoing efforts include the development of a Fortran standard library and package manager, the fostering of a friendly and welcoming online community, improved compiler support, and language feature development. The lessons learned are common across contemporary programming languages and help reduce the learning curve and increase adoption of Fortran
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