307 research outputs found

    A lower bound on the eccentric connectivity index of a graph

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    AbstractIn pharmaceutical drug design, an important tool is the prediction of physicochemical, pharmacological and toxicological properties of compounds directly from their structure. In this regard, the Wiener index, first defined in 1947, has been widely researched, both for its chemical applications and mathematical properties. Many other indices have since been considered, and in 1997, Sharma, Goswami and Madan introduced the eccentric connectivity index, which has been identified to give a high degree of predictability. If G is a connected graph with vertex set V, then the eccentric connectivity index of G, ξC(G), is defined as ∑v∈Vdeg(v)ec(v), where deg(v) is the degree of vertex v and ec(v) is its eccentricity. Several authors have determined extremal graphs, for various classes of graphs, for this index. We show that a known tight lower bound on the eccentric connectivity index for a tree T, in terms of order and diameter, is also valid for a general graph G, of given order and diameter

    Activity of different desoximetasone preparations compared to other topical corticosteroids in the vasoconstriction assay

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    Introduction: We report on a double-blind, vehicle-controlled, single-center confirmatory study with random assignment. The purpose of the study was to investigate the topical bioavailability of different topical corticosteroid formulations in healthy human beings focussing on desoximetasone (DM). Materials and Methods: Two DM 0.25% formulations {[}ointment (DM-o) and fatty ointment (DM-fo, water-free); class III corticosteroids], the corresponding active ingredient-free vehicles and three comparators of different strength {[}clobetasol propionate 0.05% (CP 0.05%), fatty ointment, class IV; hydrocortisone (HC) 1%, fatty ointment, class I, and betamethasone (BM) 0.05%, fatty ointment, class III] were tested using the vasoconstriction assay. The degree of vasoconstriction (blanching) in the treatment field was compared to the one found in untreated control fields using chromametric measurements and clinical assessment. Results/Conclusion: DM-o 0.25%, DM-fo 0.25% and BM 0.05% showed similar vasoconstrictive potential, i.e., clear blanching. In fact, both DM preparations were proven to be non-inferior to BM 0.05%, while CP 0.05% was found a little less active. HC 1.0% and the DM vehicles showed no clear-cut vasoconstrictive effect. No adverse events related to the study medications were observed. Good topical bioavailability of both DM formulations was detected by chromametric measurement and clinical assessment. Copyright (C) 2008 S. Karger AG, Basel

    Unitary chiral dynamics in J/Psi to VPP decays and the role of scalar mesons

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    We make a theoretical study of the J/Psi decays into \omega\pi\pi, \phi\pi\pi, \omega K \bar{K} and \phi K\bar{K} using the techniques of the chiral unitary approach stressing the important role of the scalar resonances dynamically generated through the final state interaction of the two pseudoscalar mesons. We also discuss the importance of new mechanisms with intermediate exchange of vector and axial-vector mesons and the role played by the OZI rule in the J/\Psi\phi\pi\pi vertex, quantifying its effects. The results nicely reproduce the experimental data for the invariant mass distributions in all the channels considered.Comment: 29 pages, 10 figure

    Blood pressure estimation from photoplethysmogram and electrocardiogram signals using machine learning

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    Blood pressure measurement is a significant part of preventive healthcare and has been widely used in clinical risk and disease management. However, conventional measurement does not provide continuous monitoring and sometimes is inconvenient with a cuff. In addition to the traditional cuff-based blood pressure measurement methods, some researchers have developed various cuff-less and noninvasive blood pressure monitoring methods based on Pulse Transit Time (PTT). Some emerging methods have employed features of either photoplethysmogram (PPG) or electrocardiogram (ECG) signals, although no studies to our knowledge have employed the combined features from both PPG and ECG signals. Therefore this study aims to investigate the performance of a predictive, machine learning blood pressure monitoring system using both PPG and ECG signals. It validates that the employment of the combination of PPG and ECG signals has improved the accuracy of the blood pressure estimation, compared with previously reported results based on PPG signal only. © 2018 Institution of Engineering and Technology. All rights reserved

    Particulate air pollutants, APOE alleles and their contributions to cognitive impairment in older women and to amyloidogenesis in experimental models

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    Exposure to particulate matter (PM) in the ambient air and its interactions with APOE alleles may contribute to the acceleration of brain aging and the pathogenesis of Alzheimer's disease (AD). Neurodegenerative effects of particulate air pollutants were examined in a US-wide cohort of older women from the Women's Health Initiative Memory Study (WHIMS) and in experimental mouse models. Residing in places with fine PM exceeding EPA standards increased the risks for global cognitive decline and all-cause dementia respectively by 81 and 92%, with stronger adverse effects in APOE ɛ4/4 carriers. Female EFAD transgenic mice (5xFAD+/−/human APOE ɛ3 or ɛ4+/+) with 225 h exposure to urban nanosized PM (nPM) over 15 weeks showed increased cerebral β-amyloid by thioflavin S for fibrillary amyloid and by immunocytochemistry for Aβ deposits, both exacerbated by APOE ɛ4. Moreover, nPM exposure increased Aβ oligomers, caused selective atrophy of hippocampal CA1 neurites, and decreased the glutamate GluR1 subunit. Wildtype C57BL/6 female mice also showed nPM-induced CA1 atrophy and GluR1 decrease. In vitro nPM exposure of neuroblastoma cells (N2a-APP/swe) increased the pro-amyloidogenic processing of the amyloid precursor protein (APP). We suggest that airborne PM exposure promotes pathological brain aging in older women, with potentially a greater impact in ɛ4 carriers. The underlying mechanisms may involve increased cerebral Aβ production and selective changes in hippocampal CA1 neurons and glutamate receptor subunits

    Chiral Symmetry and light resonances in hot and dense matter

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    We present a study of the ππ\pi\pi scattering amplitude in the σ\sigma and ρ\rho channels at finite temperature and nuclear density within a chiral unitary framework. Meson resonances are dynamically generated in our approach, which allows us to analyze the behavior of their associated scattering poles when the system is driven towards chiral symmetry restoration. Medium effects are incorporated in three ways: (a) by thermal corrections of the unitarized scattering amplitudes, (b) by finite nuclear density effects associated to a renormalization of the pion decay constant, and complementarily (c) by extending our calculation of the scalar-isoscalar channel to account for finite nuclear density and temperature effects in a microscopic many-body implementation of pion dynamics. Our results are discussed in connection with several phenomenological aspects relevant for nuclear matter and Heavy-Ion Collision experiments, such as ρ\rho mass scaling vs broadening from dilepton spectra and chiral restoration signals in the σ\sigma channel. We also elaborate on the molecular nature of ππ\pi\pi resonances.Comment: 14 pages, 14 figures. Contribution to Hard Probes 2008, Illa de A Toxa, Spain, June 8th-14th 200

    Anorthosite formation and emplacement coupled with differential tectonic exhumation of ultrahigh-temperature rocks in a Sveconorwegian continental back-arc setting

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    The tectonic setting and mechanisms and duration of emplacement of Proterozoic massif-type anorthosites and the significance of typically associated ultrahigh-temperature (UHT) host rocks have been debated for decades. This is particularly true of the Rogaland Anorthosite Province (RAP) in the SW Sveconorwegian Orogen. Earlier studies suggest that the RAP was emplaced over 1–3 Myr around 930 Ma towards the end of orogenesis, resulting in an up to 15–20 km-wide contact metamorphic aureole. However, our structural observations show that the RAP is located in the footwall of a 15 km-wide extensional detachment (Rogaland Extensional Detachment, RED), separating the intrusions and their UHT host rocks from weakly metamorphosed rocks in the hanging wall. U–Pb zircon dating of leucosome in extensional pull-aparts associated with the RED yields ages of 950–935 Ma, consistent with Re–Os molybdenite ages from brittle extensional structures in the hanging-wall block that range between 980 and 930 Ma. A metapelite in the immediate vicinity of the RAP yields a 950 Ma U–Pb age of matrix-hosted monazite, and part of the RAP was intruded by the Storgangen norite dike at ca. 950 Ma, providing a minimum age of emplacement. These ages are consistent with Ar–Ar hornblende and biotite ages that show rapid cooling of the footwall before 930 Ma, but slow cooling of the hanging wall. Field and geochronologic data suggest that the RAP formed and was emplaced over a long period of time, up to 100 Myr, with different emplacement mechanisms reflecting an evolving regional stress regime. The distribution of UHT rocks around the RAP reflects differential extensional exhumation between 980 and 930 Ma, not contact metamorphism. The duration and style of orogenic activity and externally (as opposed to gravitationally) driven extension suggest that the RAP formed in a continental back-arc setting

    Effect of laser treatment on the attachment and viability of mesenchymal stem cell responses on shape memory NiTi alloy

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    The objectives of this study were to investigate the effect of laser-induced surface features on the morphology, attachment and viability of mesenchymal stem cells (MSCs) at different periods of time, and to evaluate the biocompatibility of different zones: laser-melted zone (MZ), heat-affected zone (HAZ) and base metal (BM) in laser-treated NiTi alloy. The surface morphology and composition were studied by scanning electron microscope (SEM) and X-ray photoemission spectroscopy (XPS), respectively. The cell morphology was examined by SEM while the cell counting and viability measurements were done by hemocytometer and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The results indicated that the laser-induced surface features, such as surface roughening, presence of anisotropic dendritic pattern and complete surface Ni oxidation were beneficial to improve the biocompatibility of NiTi as evidenced by the highest cell attachment (4 days of culture) and viability (7 days of culture) found in the MZ. The biocompatibility of the MZ was the best, followed by the BM with the HAZ being the worst. The defective and porous oxide layer as well as the coarse grained structure might attribute to the inferior cell attachment (4 days of culture) and viability (7 days of culture) on the HAZ compared with the BM which has similar surface morphology. © 2014 Elsevier B.V

    Mutations in MAP3K7 that Alter the Activity of the TAK1 Signaling Complex Cause Frontometaphyseal Dysplasia.

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    Frontometaphyseal dysplasia (FMD) is a progressive sclerosing skeletal dysplasia affecting the long bones and skull. The cause of FMD in some individuals is gain-of-function mutations in FLNA, although how these mutations result in a hyperostotic phenotype remains unknown. Approximately one half of individuals with FMD have no identified mutation in FLNA and are phenotypically very similar to individuals with FLNA mutations, except for an increased tendency to form keloid scars. Using whole-exome sequencing and targeted Sanger sequencing in 19 FMD-affected individuals with no identifiable FLNA mutation, we identified mutations in two genes-MAP3K7, encoding transforming growth factor β (TGF-β)-activated kinase (TAK1), and TAB2, encoding TAK1-associated binding protein 2 (TAB2). Four mutations were found in MAP3K7, including one highly recurrent (n = 15) de novo mutation (c.1454C>T [ p.Pro485Leu]) proximal to the coiled-coil domain of TAK1 and three missense mutations affecting the kinase domain (c.208G>C [p.Glu70Gln], c.299T>A [p.Val100Glu], and c.502G>C [p.Gly168Arg]). Notably, the subjects with the latter three mutations had a milder FMD phenotype. An additional de novo mutation was found in TAB2 (c.1705G>A, p.Glu569Lys). The recurrent mutation does not destabilize TAK1, or impair its ability to homodimerize or bind TAB2, but it does increase TAK1 autophosphorylation and alter the activity of more than one signaling pathway regulated by the TAK1 kinase complex. These findings show that dysregulation of the TAK1 complex produces a close phenocopy of FMD caused by FLNA mutations. Furthermore, they suggest that the pathogenesis of some of the filaminopathies caused by FLNA mutations might be mediated by misregulation of signaling coordinated through the TAK1 signaling complex
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