Mangiferin: A Promising Anticancer Bioactive

Of late, several biologically active antioxidants from natural products have been investigated by the researchers in order to combat the root cause of carcinogenesis, i.e., oxidative stress. Mangiferin, a therapeutically active C-glucosylated xanthone, is extracted from pulp, peel, seed, bark and leaf of Mangifera indica. These polyphenols of mangiferin exhibit antioxidant properties and tend to decrease the oxygen-free radicals, thereby reducing the DNA damage. Indeed, its capability to modulate several key inflammatory pathways undoubtedly helps in stalling the progression of carcinogenesis. The current review article emphasizes an updated account on the patents published on the chemopreventive action of Mangiferin, apoptosis induction made on various cancer cells, along with proposed antioxidative activities and patent mapping of other important therapeutic properties. Considering it as promising polyphenol, this paper would also summarize the diverse molecular targets of Mangiferin

Characteristic Energy of the Coulomb Interactions and the Pileup of States

Tunneling data on $\mathrm{La_{1.28}Sr_{1.72}Mn_2O_7}$ crystals confirm Coulomb interaction effects through the $\sqrt{\mathrm{E}}$ dependence of the density of states. Importantly, the data and analysis at high energy, E, show a pileup of states: most of the states removed from near the Fermi level are found between ~40 and 130 meV, from which we infer the possibility of universal behavior. The agreement of our tunneling data with recent photoemission results further confirms our analysis.Comment: 4 pages, 4 figures, submitted to PR

Challenges in Optimization of a Stationary Tomographic Molecular Breast Imaging System

A prototype Molecular Breast Imaging (MBI) system is currently under development, motivated by the need of a practical low-dose system for use in patients with dense breast tissue, where conventional mammography is limited. The system is based on dual opposing CZT detector arrays and multi-pinhole collimators which allow for multiplexing in the projection data. We have performed optimization of various design parameters based on either contrast-to-noise ratio (CNR) in the reconstructed images or area under the localization receiver operating characteristics curve (LROC-AUC) obtained using the scan statistic model. The optimizations were based on simulated data, and the parameters investigated were pinhole size and opening angle, pinhole separation and collimator-to-detector separation. The two optimization approaches resulted in similar design parameters, allowing for reconstruction of tomographic images with high CNR and lesion detectability, which can lead to a reduced dose or scan time as compared to planar MBI

Magma mixing and high fountaining during the 1959 K īlauea Iki eruption, Hawai'i

The 1959 Kīlauea Iki eruption provides a unique opportunity to investigate the process of shallow magma mixing, its impact on the magmatic volatile budget and its role in triggering and driving episodes of Hawaiian fountaining. Melt inclusions hosted by olivine record a continuous decrease in H2O concentration through the 17 episodes of the eruption, while CO2 concentrations correlate with the degree of post-entrapment crystallization of olivine on the inclusion walls. Geochemical data, when combined with the magma budget and with contemporaneous eruption observations, show complex mixing between episodes involving hot, geochemically heterogeneous melts from depth, likely carrying exsolved vapour, and melts which had erupted at the surface, degassed and drained-back into the vent. The drained-back melts acted as a coolant, inducing rapid cooling of the more primitive melts and their olivines at shallow depths and inducing crystallization and vesiculation and triggering renewed fountaining. A consequence of the mixing is that the melts became vapor-undersaturated, so equilibration pressures cannot be inferred from them using saturation models. After the melt inclusions were trapped, continued growth of vapor bubbles, caused by enhanced post-entrapment crystallization, sequestered a large fraction of CO2 from the melt within the inclusions. This study, while cautioning against accepting melt inclusion CO2 concentrations “as measured” in mixed magmas, also illustrates that careful analysis and interpretation of post-entrapment modifications can turn this apparent challenge into a way to yield novel useful insights into the geochemical controls on eruption intensity.IS was supported by a NERC-funded studentship and a USGS Jack Kleinman Grant for Volcano Research. ME acknowledges NERC ion probe grant IMF376/0509. BH’s participation was funded by NSF EAR-1145159. We acknowledge the NERC Edinburgh Ion Microprobe facility, where we undertook the SIMS analyses.This version is the author accepted manuscript and will be under embargo until the 6th of June 2015. The final version has been published by Elsevier in Earth and Planetary Science Letters here: http://www.sciencedirect.com/science/article/pii/S0012821X14003264

Design of an Ultra-low-dose, Stationary, Tomographic Molecular Breast Imaging System

Molecular Breast Imaging (MBI) has been shown to have high sensitivity in detection of cancer, even in patients with dense breasts where conventional mammography has issues. However the technique has limited acceptance due to the relatively high radiation dose and long imaging time. Improved lesion detection can be achieved using tomography, however this normally involves detector motion and complex mechanics. Our goal is to develop a low-dose stationary tomographic MBI system with similar or better sensitivity for lesion detection to conventional planar MBI. The proposed system utilizes state-of-the-art cadmium zinc telluride (CZT) detectors based on 2mm pixels, with sub-pixelization and depth of interaction (DOI) capability, combined with densely packed multi-pinhole collimators. Use of closely-spaced pinholes improves efficiency and angular sampling, but results in significant multiplexing. De-multiplexing algorithms have been developed that take advantage of the DOI acquisition to achieve tomographic reconstruction using two opposing planar detectors which apply mild compression to the breast. Simulation studies of multiple lesions with clinically realistic contrast have been used to demonstrate the feasibility of the design and to characterize the expected performance. Reconstruction without de-multiplexing resulted in significant artefacts. De-multiplexing without DOI had limited success but with DOI resulted in artefact-free images, with good contrast and axial plane definition. Lesion detectability was preserved even with reduction of acquisition time (or radiation dose) by a factor of 4. Further optimization has potential for even greater dose reduction. A prototype system is currently being constructed to validate these findings

A New Concept for a Low-Dose Stationary Tomographic Molecular Breast Imaging Camera Using 3D Position Sensitive CZT Detectors

Pixelated CZT detectors have been used in a variety of molecular imaging applications for many years. The interplay of gamma camera and collimator geometric design, gantry motion, and image reconstruction determines the image quality and dose-time-FOV trade-offs. In particular, Molecular Breast Imaging (MBI) has been shown to provide excellent diagnostic results in patients with dense breast tissue, but higher than mammography patient dose and long imaging time impede its wide adoption. We propose a new transformative system concept combining the advantages of CZT detectors (superior energy and position resolution and depth of interaction sensing), multi-pinhole collimation and novel image reconstruction to mitigate those drawbacks without compromising diagnostic content. The closely spaced pinholes allow tomographic image reconstruction, improve sensitivity and angular sampling, but result in significant multiplexing. Novel de-multiplexing algorithms have been developed to mitigate the adverse multiplexing artefacts using the DOI. GATE simulations of the new camera demonstrate a potential to reduce the patient dose by at least a factor of 5 in comparison to planar MBI, thus reducing the dose to the level of an average mammography scan. The first prototype has been built at Kromek with 3D position sensitive CZT detectors and is being evaluated using an "activity-painting"setup with a point 57Co source. Initial results demonstrate the expected performance improvement with the use of sub-pixelisation and DOI. The next steps of the development will include accurate evaluation of the image quality and the dose reduction followed by building a larger scale clinical prototype using optimised detector design

Monotonic Distributive Semilattices

In the study of algebras related to non-classical logics, (distributive) semilattices are always present in the background. For example, the algebraic semantic of the {→, ∧, ⊤}-fragment of intuitionistic logic is the variety of implicative meet-semilattices (Chellas 1980; Hansen 2003). In this paper we introduce and study the class of distributive meet-semilattices endowed with a monotonic modal operator m. We study the representation theory of these algebras using the theory of canonical extensions and we give a topological duality for them. Also, we show how our new duality extends to some particular subclasses.Fil: Celani, Sergio Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; ArgentinaFil: Menchón, María Paula. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A Statistical DOI Estimation Algorithm for a SiPM-Based Clinical SPECT Insert

A prototype clinical brain SPECT insert has been designed for use in simultaneous SPECT/MRI. The system utilises novel slit-slat collimators which, like pinhole collimators, suffers from parallax errors due to the large incident angle of photons. A statistical algorithm has been developed to determine the depth-of-interaction (DOI) with a view to improving image performance. The importance of DOI correction was demonstrated using Monte Carlo simulation. This simulation also indicated that 4 DOI layers (3×1.5 mm+3.5 mm) may be sufficient. The improvement in event localisation was demonstrated on a single detector before implementing the algorithm on the full clinical prototype where some limitations in event localisation in layers close to the readout plane were observed. Nevertheless DOI enabled the rejection of poorly localised events with improved resolution in reconstructed line sources

Implications of the Partial Ring Design for a Clinical SPECT Insert

The INSERT system is a stationary SPECT insert designed for clinical SPECT/MRI. The system has been evaluated as a standalone SPECT scanner and here the image reconstruction is evaluated to determine the implications of its design. A two-step image acquisition can be implemented to overcome the limitations of the partial ring design. The image quality and activity linearity are evaluated through a set of point sources and vials of varying activity concentration. The evaluation highlighted areas where image reconstruction and data processing needed to improve before proceeding to simultaneous SPECT/MRI acquisitions. We have shown that the proposed dual acquisition method can produce improved image quality through the use of modified data acquisition and reconstruction protocols