765 research outputs found

    An Improved Approach for Contrast Enhancement of Spinal Cord Images based on Multiscale Retinex Algorithm

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    This paper presents a new approach for contrast enhancement of spinal cord medical images based on multirate scheme incorporated into multiscale retinex algorithm. The proposed work here uses HSV color space, since HSV color space separates color details from intensity. The enhancement of medical image is achieved by down sampling the original image into five versions, namely, tiny, small, medium, fine, and normal scale. This is due to the fact that the each versions of the image when independently enhanced and reconstructed results in enormous improvement in the visual quality. Further, the contrast stretching and MultiScale Retinex (MSR) techniques are exploited in order to enhance each of the scaled version of the image. Finally, the enhanced image is obtained by combining each of these scales in an efficient way to obtain the composite enhanced image. The efficiency of the proposed algorithm is validated by using a wavelet energy metric in the wavelet domain. Reconstructed image using proposed method highlights the details (edges and tissues), reduces image noise (Gaussian and Speckle) and improves the overall contrast. The proposed algorithm also enhances sharp edges of the tissue surrounding the spinal cord regions which is useful for diagnosis of spinal cord lesions. Elaborated experiments are conducted on several medical images and results presented show that the enhanced medical pictures are of good quality and is found to be better compared with other researcher methods.Comment: 13 pages, 6 figures, International Journal of Imaging and Robotics. arXiv admin note: text overlap with arXiv:1406.571

    The Radiation Transfer at a Layer of Magnetized Plasma With Random Irregularities

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    The problem of radio wave reflection from an optically thick plane monotonous layer of magnetized plasma is considered at present work. The plasma electron density irregularities are described by spatial spectrum of an arbitrary form. The small-angle scattering approximation in the invariant ray coordinates is suggested for analytical investigation of the radiation transfer equation. The approximated solution describing spatial-and-angular distribution of radiation reflected from a plasma layer has been obtained. The obtained solution has been investigated numerically for the case of the ionospheric radio wave propagation. Two effects are the consequence of multiple scattering: change of the reflected signal intensity and anomalous refraction.Comment: 22 pages, 4 figure

    Quantum sticking, scattering and transmission of 4He atoms from superfluid 4He surfaces

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    We develop a microscopic theory of the scattering, transmission, and sticking of 4He atoms impinging on a superfluid 4He slab at near normal incidence, and inelastic neutron scattering from the slab. The theory includes coupling between different modes and allows for inelastic processes. We find a number of essential aspects that must be observed in a physically meaningful and reliable theory of atom transmission and scattering; all are connected with multiparticle scattering, particularly the possibility of energy loss. These processes are (a) the coupling to low-lying (surface) excitations (ripplons/third sound) which is manifested in a finite imaginary part of the self energy, and (b) the reduction of the strength of the excitation in the maxon/roton region

    BLOC-2 targets recycling endosomal tubules to melanosomes for cargo delivery.

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    Hermansky-Pudlak syndrome (HPS) is a group of disorders characterized by the malformation of lysosome-related organelles, such as pigment cell melanosomes. Three of nine characterized HPS subtypes result from mutations in subunits of BLOC-2, a protein complex with no known molecular function. In this paper, we exploit melanocytes from mouse HPS models to place BLOC-2 within a cargo transport pathway from recycling endosomal domains to maturing melanosomes. In BLOC-2-deficient melanocytes, the melanosomal protein TYRP1 was largely depleted from pigment granules and underwent accelerated recycling from endosomes to the plasma membrane and to the Golgi. By live-cell imaging, recycling endosomal tubules of wild-type melanocytes made frequent and prolonged contacts with maturing melanosomes; in contrast, tubules from BLOC-2-deficient cells were shorter in length and made fewer, more transient contacts with melanosomes. These results support a model in which BLOC-2 functions to direct recycling endosomal tubular transport intermediates to maturing melanosomes and thereby promote cargo delivery and optimal pigmentation

    Superconducting dome in ferroelectric-type materials from soft mode instability

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    We present a minimal theory of superconductivity enhancement in ferroelectric-type materials. Simple expressions for the optical mode responsible for the soft mode transition are assumed. A key role is played by the anharmonic phonon damping which is modulated by an external control parameter (electron doping or mechanical strain) causing the appearance of the soft mode. It is shown that the enhancement in the superconducting critical temperature Tc upon approaching the ferroelectric transition from either side is due to the Stokes electron-phonon scattering processes promoted by strong phonon damping effects

    DESIGN AND OPTIMIZATION OF DOXORUBICIN HCL PRONIOSOMES BY-DESIGN OF EXPERIMENT

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    Objective: The present research work was designed to formulate and optimize doxorubicin HCl proniosomes by design of experiment (DoE). Methods: A 4-factor, 3-level Box-Behnken design was used to explain multiple linear regression analysis and contour 3D plot responses. The independent variables selected were tween 20, cholesterol, hydration volume and sonication time; dependent variables percentage entrapment efficiency (PEE), mean vesicle size (MVS). Based on the Box-Behnken design 29 trial runs were studied and optimized for PEE and MVS. Further "Model F-Value" was calculated to confirm the omission of insignificant terms from the full-model equation to derive a multiple linear regression analysis to predict the PEE and MVS of niosomes derived from proniosomes. 3D plots were constructed to show the influence of independent variables on dependent variables. Results: PEE of doxorubicin HCl proniosomes was found to be in the range of 40.21-87.5%. The polynomial equation for PEE exhibited a good correlation coefficient (0.5524) and the "Model F-Value" of 7.41 implies the model is significant. P-values less than 0.0500 indicate model terms are significant. The MVS of doxorubicin HCl proniosomes was found to be in the range of 325.2 nm to 420.25 nm. The mathematical model generated for MVS (R2) was found to be significant with model F-value of 54.22. There is only a 0.01% chance that a "Model F-Value" this large could occur due to noise (P<0.0500) and R2 value of 0.9004. Conclusion: The DoE of Box-Behnken design demonstrated the role of the derived equation, 3D plot in predicting the values of dependent variables for the preparation and optimization of doxorubicin HCl proniosomes. The results suggest that doxorubicin HCl proniosomes can act as a promising carrier

    PREPARATION, EVALUATION AND STABILITY OF LAMIVUDINE LOADED ALGINATE-TAMARIND MUCILAGE MICROSPHERES

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    Objective: The objective of the present study was to investigate the possibility of obtaining a controlled, relatively constant effective level of lamivudine microspheres. Methods: Lamivudine loaded sodium alginate (SA) and tamarind mucilage(TM) mucoadhesive microspheres were prepared by ionic gelation technique with three different proportions of SA and TM with different concentrations of CaCl2. The prepared microspheres were evaluated for drug loading, particle size distribution, surface morphology, FTIR, in vitro wash off, in vitro release and stability studies. Results: The microspheres were found to be free flowing having diameter ranging from 769.22 to 978.56 µm, drug encapsulation efficiency (DEE) was found to be 65.28 to 92.33%. Percent drug release after 12 h were ranging from 85±1.51 to 97±1.44. In vitro release profile of all formulations shows slow controlled release up to 12 h. In vitro wash off studies shown fairly good mucoadhesivity with 20% microspheres adhered after 6h. Stability studies showed that no significant change in particle size and maximum DEE in comparison to the formulation stored at room temperature. Results: The lamivudine loaded SA-TM mucoadhesive microspheres can be conveniently prepared which showed better result and it may be used full for controlling the drug release and improve the bioavailability

    DRUMSTICK MUCILAGE MICROSPHERES FOR CONTROLLED RELEASE OF LAMIVUDINE: DESIGN, OPTIMIZATION AND IN VITRO EVALUATION

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    Objective: The objective of this study was to design and evaluate controlled release mucoadhesive microspheres of lamivudine using mucoadhesive polymers and mucilage. Methods: Mucoadhesive microspheres of lamivudine were formulated by ionic gelation method. The response surface methodology was adapted for optimization of formulation using central composite design (CCD) for two factors at three levels each was employed to study the effect of independent variables, Sodium alginate-drumstick mucilage (X1) and calcium chloride (CaCl2) concentration (X2) on dependent variables, namely drug encapsulation efficiency (DEE) and particle size (PS). Optimized drumstick mucilage mucoadhesive microspheres of lamivudine were obtained by using numerical optimization of desirability approach. The observed microspheres were coincided well with the predicted values by the experimental design. Results: The microspheres formed were spherical in shape, and Particle size (PS) ranged between 681.63-941.57μm. Drug encapsulation efficiency (DEE) was ranged between 69.63-94.56 %. The drug release for an optimized formulation was 96.58 %. The mechanism of drug release from microspheres followed Korsemeyer’s-Peppas and exponential ‘n’ value was greater than 0.45, indicating the drug release was non-fickian i.e., swelling followed by erosion mechanism. Conclusion: This work suggests that mucoadhesive microspheres, an effective drug delivery system for lamivudine, can be prepared using drumstick mucilage in improving the bioavailability of the drug

    ANFIS Based Temporally Ordered Routing Algorithm to Enhance the Performance in Mobile Ad-hoc Networks

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    A Mobile Ad hoc network (MANET) consists of mobile nodes, a router with multiple hosts and wireless communication devices. Mobile Adhoc Networks can operate without any fixed infrastructure and can survive rapid changes in the network topology. Link failure and route failure takes place. Provisioning of QoS is a problem in MANETs. TORA is the only protocol which supports either Proactive or Reactive modes in routing. In this paper, we incorporated the ANFIS to the existing TORA to enhance the performance. Evaluating the performance of ANFIS-TORA is the simulation by using OPNET MODELLER. Evaluating the relative performance with respect to performance metrics are Throughput, End-to-End delay, and Network Load. We generate various simulation scenarios with varying network size such as small, medium and large. In this paper, ANFIS based TORA for MANETs are considered and their performance was analyzed for different network size. From the simulation results, we conclude that ANFIS based TORA outperforms for small medium and large network. Throughput was increased by 48.27% in small network, 61.29% in medium network and 8.29% in the large network in Reactive mode. In Proactive, the throughput is increased by 103.46% in small network, 4.58% in medium network and 5.05% in large network
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