Magnetic field driven enhanced ferroelectric switching in self-grown ferroelectric-ferromagnetic composite in the BiFeO3-BaTiO3 multiferroic alloy system

Over the years attempts have been made to compensate for the inherent weaknesses in the bulk state of the multiferroic BiFeO3, such as high leakage current and the absence of ferromagnetic correlation, and exploit its magnetoelectric potential by forming solid solutions with other perovskites. Studies in the recent few years have shown that alloying of BiFeO3 with BaTiO3, both with and without additives, can induce both ferroelectric and ferromagnetic switching. While the coexistence of both the ferroic orders is encouraging from the view point of technological applications, the origin of ferromagnetism in this system remains elusive. Here, we synthesized such compositions and carried out a detailed structural analysis employing magnetic separation of the powder particles. We found that the origin of ferromagnetism lies in the spontaneous precipitation of a minor ( ~ 1 wt %) barium hexaferrite (BaFe9O19) phase, often undetected in routine x-ray diffraction studies of powders sampled from the entire specimen. We also demonstrate that inspite of the insignificant fraction the ferrimagnetic phase, this self-grown composite exhibit noticeably enhanced ferroelectric switching in the presence of external magnetic field. We obtained a dc magnetoelectric coupling of ~ 9 x 10-8 s/m, a value which is comparable to what has been reported for layered ferroelectric/ferromagnetic laminates and bilayer thin film ferroelectric-ferromagnetic hetrostructures. Our study suggests that reasonably large magnetoelectric coupling is realizable in simple 0-3 ferroelectric-ferromagnetic bulk composites provided synthesis strategies are developed which induces spontaneous precipitation of the ferromagnetic phase in small volume fraction to ensure good insulating behaviour of the composite thus developed.Comment: 21 pages, 7 figure

CORRELATION OF CONCEPT OF AMA AND FREE RADICAL THEORY

Majority of the endogenous disease begins with the formation of Ama in the body. It has tremendous capacity to vitiate the Doshas and disturbing the homeostasis (Dhatu-samya). Ama is the resultant of improper digestion or partially digestion of the food particle due to hypofunction of Jatharagni and also due to accumulation of mala in the body and also considered as Prathamdoshadusti. It may be considered as partially or incompletely metabolized Dhatu in case of Dhatvagnimandya. In modern parameters, Ama is supposed to be deadly Free radical. Free radical is an atom/molecule that contains one or more unpaired electron, which requires neutralization by free radical scavengers. Ama is not a single entity but is a generalized term, which can be applied to many malformed substances in the body. This Ama is responsible for the production of various diseases. In the same way, free radicals are also found to be the root cause of many diseases. Here we discuss about properties and qualities in both entities, which are similar and dissimilar, also whether free radicals can be considered under Ama. The present article attempts to correlate the most recent concept of todays i. e. free radical concept with that of the concept of Ama, described in research for remedies from Ayurvedic research, which may be helpful in the presentation and care of free radicals mediated disease

ANCIENT METHODS OF RESEARCH IN AYURVEDA

Ayurveda is the Upaveda of Atharvaveda, the ancient literature which gave us the knowledge of healthier life. The absolute aim of Ayurveda is to maintain the health of a healthier person and diagnose and treat the diseased person. Ayurveda has the ability to treat many chronic diseases that are untreatable in modern medicine, it has got some very preventive and curative tools to treat the diseases, but unfortunately, due to the lack of scientific validation in various concepts, this precious gift from our ancestors is trailing. In a nutshell, Ayurveda gives human a healthy life with proven methods of medical treatment. The ancient methods of treatment are very effective and relevant in present time also. Hence, evidence-based research is highly needed for global recognition and acceptance of Ayurveda, which needs further advancements in the research methodology

A CLINICAL STUDY ON THE EFFECT OF PUNARNAVADI CHURNA, SINGHANADA GUGGULU IN THE MANAGEMENT OF AMAVATA (RHEUMATIOD ARTHRITIS)

Amavata, is firstly introduced as an independent disease in Madhav Nidana. It is a disease of Madhyam roga marga as it affects Sandhi and Hridya marma. Though Ama and Vata are the two main predominant pathogenic factors but the disease also represents Tridoshic vitiation. The affliction of joints by Vata dosha in association with Ama shows that both play equal role of Dosha and Dushya in the causation of this disease. This study includes evaluate the effect of Trial drugs Punarnavadi churna with Anupana of Rasna Saptak Qwatha and Eranda taila on the signs and symptoms of Amavata and also to evaluate the effect of trial drug with a standard drug Singhanada Guggulu on the signs and symptoms of Amavata. In short we can say that, Amavata is the resultant of improper digestion or partially digestion of the food particles due to hypofunction of Gatharagni and also due to accumulation of mala in the body and it is also considered as Pratham doshadusti. It may be considered as partially or incomplete metabolized Dathu in case of Dhatvagni mandata. This study might be helpful in breakdown Samprapti of Amavata roga and give right way to patient of Amavata

Management Of Breast Cancer Through Ayurveda

Breast cancer is the second most common cancer among women. Initial signs of cancer start in the lymph nodes located under the arm, within the breast, and near the collarbone. Many promising remedies for breast cancer are included in Ayurveda, the Indian system of medicine. Nowadays, multi-targeted herbal drugs are used as an adjuvant therapy alongside conventional medicine in the management of this type of cancer. The information for the present study was obtained from various internet sources like research articles and paper presentation documents and research book publications. The present review concentrates on the available literature found in Ayurveda regarding plants, poly-herbal and herbo mineral ayurvedic remedies available for management of breast cancer

COMPARATIVE EFFECT OF KSHARASUTRA ON MANAGEMENT OF BHAGANDARA

Bhagandara is a chronic purulent inflammation usually affects perianal region, anal canal and rectum. It initially manifested by an abscess followed by continuous discharge of pus through the tract and leads to an unhealed condition. Improper care and negligence to the disease lead the patient to seriousness occasionally. Now-a-days, management of Bhagandara with Ksharasutra is gained popularity for its minimal invasive and complete cure of the disease but corrosiveness and pain during application of Ksharasutra still remain as a drawback to the approach.  This study includes preparation of three types of Ksharasutra and comparative effect of Ksharasutra in the management of Bhagandara. Considering the above problem a thorough review was done in order to find out any solution to solve the purpose of Ksharasutra without pain. Further, it is also revealed that the corrosive agent usually in the preparation of ksharasutra is Snuhi ksheera (Euphorbia nerifolia). The relevant study proved that ksharasutra can also be prepared with Guggulu (Comiphora mukulu) and Udumbara latex (Ficus glomerata) instead of Snuhi ksheera. Thus evaluation of the effect of such Ksharasutra is not methodically done yet. In order to evaluate the effects of ksharasutra prepared out of Guggulu and Udumbara latex is selected for the purpose of the study

Secondary spin current driven efficient THz spintronic emitters

Femtosecond laser-induced photoexcitation of ferromagnet (FM)/heavy metal (HM) heterostructures have attracted attention by emitting broadband terahertz frequencies. The phenomenon relies on the formation of ultrafast spin current, which is largely attributed to the direct photoexcitation of the FM layer. However, we reveal that during the process, the FM layer also experiences a secondary excitation led by the hot electrons from the HM layer that travel across the FM/HM interface and transfer additional energy in the FM. Thus, the generated secondary spins enhance the total spin current formation and lead to amplified spintronic terahertz emission. The results also emphasize the significance of the secondary spin current, which even exceeds the primary spin currents when FM/HM heterostructures with thicker HM are used. An analytical model is developed to provide deeper insights into the microscopic processes within the individual layers, underlining the generalized ultrafast superdiffusive spin-transport mechanism.Comment: 20 pages, 3 figure

Design and Implementation of ZCS BUCK Converter

Buck converters are step-down DC-DC converters that are widely being used in different electronic devices like laptops,PDA’s,cell phones and also electric vehicles to obtain different level of voltages. These converters are nothing but ,high frequency switching devices operating on PWM principle. The need for more and more lighter and smaller electronic devices propels the need for reduced size of converters operating at higher load currents. With all these inadvertent conditions the switching frequency has jumped from KHz range to MHz range.The switching devices are made to turn on and turn off the entire load current at high di/dt , and also withstand high voltage stress across them.Due to these two effects there occurs increased power losses in these converters and reduces the efficiency significantly. The reduction in efficiency is highly unacceptable as it leads to shorter battery life and derated device conditions. The shortcomings explained above can be minimised and upto some extent eliminated if each switch is made to turn-on and turn-off when the voltage across it and/or current through it is zero at the instant of switching. The converter circuits which employ zero voltage and /or zero current switching are known as Resonant converters. In most of these converters some form of L-C resonance is used, that is why these are known as resonant converters. In this project a detailed study of zero current switching buck converters is done and also practically implemented in hardware. In addition a mathematical analysis of switching loss occuring in MOSFET’s is also presented and a short study of zero voltage switching is also appended. During the hardware implementation the Ton,Toff and operating frequency were found out and thoroughly tuned through the IC555 circuit and various waveforms across inductors,capacitors,load resistor and test points were noted down. These waveforms were found to be in precise proximity of the theoretically observed waveforms

Screening of antiangiogenic potential of twenty two marine invertebrate extracts of phylum Mollusca from South East Coast of India

ABSTRACTObjectiveTo evaluate the antiangiogenic potential of twenty two marine invertebrate species of Phylum Mollusca from south east coast of India.MethodsLive specimens of molluscan species were collected and their methanolic extracts were evaluated for preliminary antiangiogenic activity using the in ovo chick chorio-allantoic membrane assay. The extracts were further evaluated for in vivo antiangiogenic activity using chemical cautery induced corneal neovascularization assay in rats and oxygen induced retinopathy assay in rat pups.ResultsIn the chick chorio-allantoic membrane assay, four methanolic extracts of marine molluscan species viz. Meretrix meretrix, Meretrix casta, Telescopium telescopium and Bursa crumena methanolic extracts exhibited noticeable antiangiogenic activity at the tested concentration of 200 μg whereby they significantly inhibited the VEGF induced proliferation of new blood vessels. Among these four extracts, the methanolic extract of Meretrix casta exhibited relatively higher degree of antiangiogenic activity with an inhibitiory percentage (64.63%) of the VEGF induced neovascularization followed by the methanolic extracts of Telescopium telescopium (62.02%), Bursa crumena (60.48%) and Meretrix meretrix (47.01%). These four methanolic extracts were further evaluated for in vivo antiangiogenic activity whereby the methanolic extract of Telescopium telescopium exhibited most noticeable inhibition (42.58%) of the corneal neovascularization in rats in comparison to the sham treated group, and also exhibited most noticeable inhibition (31.31%) of the oxygen induced retinal neovascularization in rat pups in comparison to the hyperoxia group that was observed for considerable retinal neovascularization.ConclusionsThe significant antiangiogenic activity evinced by the extract of Telescopium telescopium merits further investigation for ocular neovascular diseases