258 research outputs found

    The Science Behind Memory: Hippocampal Neural Cell Assemblies

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    ANALYSIS OF ARTAVA (MENSTRUATION) IN CONTEXT OF SHARIRA RACHANA

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    The proper understanding of terminology is vital for a systematic knowledge of any structure especially in context of Sharira Rachana. A term is a structured set of concepts and their designations in a specific field. The proper terminology is concerned with relationship between the concepts and also makes a fundamental pillar. The aim of present article is to compiled, critically analyze the terminology related to Artava i.e. Raja, Artava and Shonita and elaborate the fundamental concepts behind those terminologies in various classics of Ayurveda. Presence of Raja, Artava since childhood, concept of Raja, Shonita, character of Artava and difference between Artava and Shonita are mentioned as reviewed literature. About one month of time period is needed in the formation of Artava in adult female’s means to reach the Artava from its originating place to destination place or from Yakrita and Pleeha to Garbhashaya (Yoni) and this makes complete passage of Artava. Artava have Agneya Pradhana nature as source of Agneyatattva for Garbha while Anushanasheeta composition of Rakta Dhatu laid the foundation of Dhatu for body. Raja is the flowing constituent of Artava and Beeja as constituent of Artava is the source of Garbha. Both Artava and Rakta Dhatu are formed from Rasa Dhatu by Ranjanakriya. This process converts the Saumyabhava to Agneyabhava. This article can be helpful to understand the various terminologies related to the Artava

    Formulation Development & Evaluation of Buffered Tablet of Proton Pump Inhibitors Drug Rabeprazole Sodium

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    The aim of present study was to prepare buffered tablets of acid labile drug, Rabeprazole sodium for oral administration using buffering agents to protect a drug from gastric fluid. Rabeprazole belongs to a class of antisecretory compounds (substituted benzimidazole proton-pump inhibitors) that do not exhibit anticholinergic or histamine H2-receptor antagonist properties, but suppress gastric acid secretion by inhibiting the gastric H+, K+ATPase at the secretory surface of the gastric parietal cell. Rabeprazole blocks the final step of gastric acid secretion. The tablets were prepared by direct compression and wet granulation method. The formulations contain water soluble buffers such as sodium bicarbonate and trisodium phosphate as well as water insoluble buffers as magnesium oxide, magnesium hydroxide and calcium carbonate and crospovidone as superdisintegrant. Preformulation studies like angle of repose, bulk density, tapped density, Carr’s index, hausner’s ratios, DSC and drug/excipient compatibility study were conducted and evaluated for hardness, friability, weight variation, drug content, disintegration and in-vitro dissolution. In the present study, pH of F6 batch was found to be optimum and disintegration time is 42 sec. The drug release was found to show maximum drug release in case of F6 with 99.3% in 60 minutes. In case of stability studies study of the optimized batch, all the results were found to be satisfactory and within limits. There were no significant changes after the period of 1 month study. Keywords: Rabeprazole sodium, Proton-pump inhibitors, Buffered tablet, Superdisintegrants, Buffering agent

    Formulation Development and Evaluation of Floating Microsphere of Famotidine for the Treatment of Peptic Ulcer

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    The purpose of this research was to prepare a floating drug delivery system of famotidine. The floating microspheres can be prepared for the improvement of absorption and bioavailability of famotidine by retaining the system in the stomach for prolonged period of time. Floating microspheres of famotidine were prepared using different polymers like ethyl cellulose, hydroxy propyl methyl cellulose by solvent diffusion-evaporation method. The microspheres had smooth surfaces with free-flowing and good-packing properties. The yield of the microspheres was up to 73.32±0.14% and ethyl cellulose microspheres entrapped the maximum amount of the drug. Scanning electron microscopy confirmed their hollow structures with sizes in 331.6 nm. The prepared microspheres exhibited prolonged drug release and Percentage buoyancy was found to 73.25±0.23. The formulated batches were evaluated for percentage yield, particle size measurement, flow properties, percent entrapment efficiency, swelling studies. The formulations were subjected to stability studies and In-vitro release and release kinetics data was subjected to different dissolution models. It was concluded that developed floating microspheres of famotidine offers a suitable and practical approach for prolonged release of drug over an extended period of time and thus oral bioavailability, efficacy and patient compliance is improved. Keywords: Famotidine, Solvent diffusion evaporation method, Ethyl cellulose, Hydroxyl propyl methyl cellulos

    MUTUAL LEARNING IN TREE PARITY MACHINES USING CUCKOO SEARCH ALGORITHM FOR SECURE PUBLIC KEY EXCHANGE

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    In Neural Cryptography, Artificial Neural Networks are used for the process of key generation and encryption. Tree Parity Machine (TPM) is a single layer neural network that approaches symmetric key exchange using the process of mutual learning. This method is exploited to design a secure key exchange protocol, where the sender and the receiver TPMs are synchronized to obtain an identically tuned weight vectors in both the networks. The synchronized TPMs are then capable of generating a key stream. The time required for synchronization depends on the initial weight vectors which are randomly initialized. In the proposed method, the process of synchronization is expedited using Cuckoo Search (CS) Algorithm used for the generation of optimal weights

    Development and Characterization of Core Shell Nanoparticle for Enhanced Drug Delivery to Treat Solid Tumor: Preparation and In-Vitro Assessment

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    Mortalities from cancer in the world are projected to continue rising, with an estimated 9 million and 11.4 million people dying from cancer in 2015 and 2030, respectively. Rates are rising as more people live to an old age and as mass lifestyle changes occur in the developing world. With present treating regimen for cancer, dose-limited toxicity is a big reason that reduces the efficacy of cancer treatments. In search for more effective cancer treatments, nanosized drug delivery systems, those are capable of delivering their drug payload selectively to cancer cells such as nanoparticles, solid lipid nanoparticles, liposomes are among the most promising approaches. Core shell nanoparticles are one of the investigated moieties in recent years that are seeking much attention nowadays for biomedical applications including the field of oncology.The present work aims at developing a core shell nanoparticle comprising Poly (D, L –lactide –co –glycolide) (PLGA) core and polyethyleneimine (PEI) shell loaded with anticancer bioactive docetaxel (DTX) for passive targeting of the tumor tissue. It is expected that incorporation of PEI will improve the uptake and subsequent release of the drug in the cytosol due to endosomal escape phenomenon. Keywords: Solid tumor; nanotechnology; nanoparticle; PLG

    Hyperpolarized Long-T1 Silicon Nanoparticles for Magnetic Resonance Imaging

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    Silicon nanoparticles are experimentally investigated as a potential hyperpolarized, targetable MRI imaging agent. Nuclear T_1 times at room temperature for a variety of Si nanoparticles are found to be remarkably long (10^2 to 10^4 s) - roughly consistent with predictions of a core-shell diffusion model - allowing them to be transported, administered and imaged on practical time scales without significant loss of polarization. We also report surface functionalization of Si nanoparticles, comparable to approaches used in other biologically targeted nanoparticle systems.Comment: supporting material here: http://marcuslab.harvard.edu/Aptekar_hyper1_sup.pd

    Symmetry breaking and quantum correlations in finite systems: Studies of quantum dots and ultracold Bose gases and related nuclear and chemical methods

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    Investigations of emergent symmetry breaking phenomena occurring in small finite-size systems are reviewed, with a focus on the strongly correlated regime of electrons in two-dimensional semicoductor quantum dots and trapped ultracold bosonic atoms in harmonic traps. Throughout the review we emphasize universal aspects and similarities of symmetry breaking found in these systems, as well as in more traditional fields like nuclear physics and quantum chemistry, which are characterized by very different interparticle forces. A unified description of strongly correlated phenomena in finite systems of repelling particles (whether fermions or bosons) is presented through the development of a two-step method of symmetry breaking at the unrestricted Hartree-Fock level and of subsequent symmetry restoration via post Hartree-Fock projection techniques. Quantitative and qualitative aspects of the two-step method are treated and validated by exact diagonalization calculations. Strongly-correlated phenomena emerging from symmetry breaking include: (I) Chemical bonding, dissociation, and entanglement (at zero and finite magnetic fields) in quantum dot molecules and in pinned electron molecular dimers formed within a single anisotropic quantum dot. (II) Electron crystallization, with particle localization on the vertices of concentric polygonal rings, and formation of rotating electron molecules (REMs) in circular quantum dots. (III) At high magnetic fields, the REMs are described by parameter-free analytic wave functions, which are an alternative to the Laughlin and composite-fermion approaches. (IV) Crystalline phases of strongly repelling bosons. In rotating traps and in analogy with the REMs, such repelling bosons form rotating boson molecules (RBMs).Comment: Review article published in Reports on Progress in Physics. REVTEX4. 95 pages with 37 color figures. To download a copy with high-quality figures, go to publication #82 in http://www.prism.gatech.edu/~ph274cy

    Direct visualization of electroporation-assisted in vivo gene delivery to tumors using intravital microscopy – spatial and time dependent distribution

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    BACKGROUND: Electroporation is currently receiving much attention as a way to increase drug and DNA delivery. Recent studies demonstrated the feasibility of electrogene therapy using a range of therapeutic genes for the treatment of experimental tumors. However, the transfection efficiency of electroporation-assisted DNA delivery is still low compared to viral methods and there is a clear need to optimize this approach. In order to optimize treatment, knowledge about spatial and time dependency of gene expression following delivery is of utmost importance in order to improve gene delivery. Intravital microscopy of tumors growing in dorsal skin fold window chambers is a useful method for monitoring gene transfection, since it allows non-invasive dynamic monitoring of gene expression in tumors in a live animal. METHODS: Intravital microscopy was used to monitor real time spatial distribution of the green fluorescent protein (GFP) and time dependence of transfection efficiency in syngeneic P22 rat tumor model. DNA alone, liposome-DNA complexes and electroporation-assisted DNA delivery using two different sets of electric pulse parameters were compared. RESULTS: Electroporation-assisted DNA delivery using 8 pulses, 600 V/cm, 5 ms, 1 Hz was superior to other methods and resulted in 22% increase in fluorescence intensity in the tumors up to 6 days post-transfection, compared to the non-transfected area in granulation tissue. Functional GFP was detected within 5 h after transfection. Cells expressing GFP were detected throughout the tumor, but not in the surrounding tissue that was not exposed to electric pulses. CONCLUSIONS: Intravital microscopy was demonstrated to be a suitable method for monitoring time and spatial distribution of gene expression in experimental tumors and provided evidence that electroporation-assisted gene delivery using 8 pulses, 600 V/cm, 5 ms, 1 Hz is an effective method, resulting in early onset and homogenous distribution of gene expression in the syngeneic P22 rat tumor model

    Instabilities in crystal growth by atomic or molecular beams

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    The planar front of a growing a crystal is often destroyed by instabilities. In the case of growth from a condensed phase, the most frequent ones are diffusion instabilities, which will be but briefly discussed in simple terms in chapter II. The present review is mainly devoted to instabilities which arise in ballistic growth, especially Molecular Beam Epitaxy (MBE). The reasons of the instabilities can be geometric (shadowing effect), but they are mostly kinetic or thermodynamic. The kinetic instabilities which will be studied in detail in chapters IV and V result from the fact that adatoms diffusing on a surface do not easily cross steps (Ehrlich-Schwoebel or ES effect). When the growth front is a high symmetry surface, the ES effect produces mounds which often coarsen in time according to power laws. When the growth front is a stepped surface, the ES effect initially produces a meandering of the steps, which eventually may also give rise to mounds. Kinetic instabilities can usually be avoided by raising the temperature, but this favours thermodynamic instabilities. Concerning these ones, the attention will be focussed on the instabilities resulting from slightly different lattice constants of the substrate and the adsorbate. They can take the following forms. i) Formation of misfit dislocations (chapter VIII). ii) Formation of isolated epitaxial clusters which, at least in their earliest form, are `coherent' with the substrate, i.e. dislocation-free (chapter X). iii) Wavy deformation of the surface, which is presumably the incipient stage of (ii) (chapter IX). The theories and the experiments are critically reviewed and their comparison is qualitatively satisfactory although some important questions have not yet received a complete answer.Comment: 90 pages in revtex, 45 figures mainly in gif format. Review paper to be published in Physics Reports. Postscript versions for all the figures can be found at http://www.theo-phys.uni-essen.de/tp/u/politi
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