2,105 research outputs found

    Dermoscopy and methyl aminolevulinate: A study for detection and evaluation of field cancerization

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    Actinic keratosis (AK) is a keratinocyte intraepidermal neoplasia UV light – induced that frequently appears in sun-exposed areas of the skin. Although historically AK was de fi ned as “ precancerous ” , actually it is considered as the earliest stage of squamous cell carcinoma (SCC) in situ. Since AKs can progress into invasive SCC, their treatment isrecommended. AKsrarely developasa singlelesion;usually multiplelesions commonly affect anen- tire area of chronically actinic damaged skin. This has led to the concept of “ fi eld cancerization ” , an area chroni- cally sun-exposed that surrounds peripherally visible lesions, in which are individualized subclinical alterations. One of the main principles endpoint in the management of AKs is the evaluation and the treatment of fi eld cancerization. In this view, in order to detect and quantify fi eld cancerization, we employed a method based on the topical application of methyl aminolevulinate (MAL) and the detection of the fl uorescence emitted by its metabolite Protoporphyrin IX (PpIX); then, considering the extension and the intensity of measured fl uores- cence, we create a score of fi eld cancerization. The results show that patients underwent to daylight PDT had a reduction of total score, from T0 to T2. Whereas in the group untreated we observed a stability of total score or a slightly worse. So, the method and the score used allows to evaluate with a good approximation the dimension of fi eld cancerization and show the modi fi cation of it after treatment

    Tameness of holomorphic closure dimension in a semialgebraic set

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    Given a semianalytic set S in a complex space and a point p in S, there is a unique smallest complex-analytic germ at p which contains the germ of S, called the holomorphic closure of S at p. We show that if S is semialgebraic then its holomorphic closure is a Nash germ, for every p, and S admits a semialgebraic filtration by the holomorphic closure dimension. As a consequence, every semialgebraic subset of a complex vector space admits a semialgebraic stratification into CR manifolds satisfying a strong version of the condition of the frontier.Comment: Published versio

    Growth laws and self-similar growth regimes of coarsening two-dimensional foams: Transition from dry to wet limits

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    We study the topology and geometry of two dimensional coarsening foams with arbitrary liquid fraction. To interpolate between the dry limit described by von Neumann's law, and the wet limit described by Marqusee equation, the relevant bubble characteristics are the Plateau border radius and a new variable, the effective number of sides. We propose an equation for the individual bubble growth rate as the weighted sum of the growth through bubble-bubble interfaces and through bubble-Plateau borders interfaces. The resulting prediction is successfully tested, without adjustable parameter, using extensive bidimensional Potts model simulations. Simulations also show that a selfsimilar growth regime is observed at any liquid fraction and determine how the average size growth exponent, side number distribution and relative size distribution interpolate between the extreme limits. Applications include concentrated emulsions, grains in polycrystals and other domains with coarsening driven by curvature

    Cerebrospinal Fluid Cytokine and Chemokine Patterns in Central Nervous System Infections, Hemorrhage and Neoplasms

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    Cytokines and chemokines are soluble proteins that act as regulators of cellular functions throughout the body. Cytokines and chemokines released in the setting of various CNS disorders appear in the CSF compartment where determination of their levels can provide insight into pathogenic processes such as neuroinflammation. We utilized the Millipore HCYTOMAG 60K assay/kit/system to perform multiplex profiling of 42 different cytokines/chemokines in the CSF of patients with a variety of distinct CNS disease processes, including infection, hemorrhage and neoplasia. CNS infections included viral (Chronic Parechovirus type 3 (HPeV3), Enterovirus (EV) 68, Adenovirus, JC virus, West Nile virus), bacterial (Mycobacterium tuberculosis, Borrelia burgdorferi, Propionibacterium acnes, Staphylococcus epidermidis, Streptococcus sp.), fungal (Cryptococcus neoformans) and single celled parasite (Toxoplasma gondii). CSF specimens negative for infectious organisms in noninflammatory conditions were selected as controls. Additional non-infectious samples tested were obtained from patients with subarachnoid hemorrhage (SAH) and following surgery for glioblastoma. The glioblastoma samples were noteworthy in having negligible elevations in the cytokines/chemokines tested. CSF from patients with SAH was elevated in only MCP-1/CCL2. Distinct patterns of cytokine/chemokine expression were detected for each infectious patient population. Picornavirus infections HPeV3 and EV68 were associated with increased levels of the monocyte chemoattractant protein MCP-1/CCL2 when compared to non-infectious, non-inflammatory samples. In contrast to chronic HPeV3 infection, EV68 encephalitis was associated with increased CSF levels of additional cytokines; CCLX1, IL-4 and IL-7. Adenovirus infection was associated with markedly higher levels of fractalkine in CSF when compared to any of the other non-inflammatory, infectious, hemorrhage or tumor cases. CSF from a Mycobacterium tuberculosis infection demonstrated increased levels of a greater variety of cytokines/chemokines than any of the other groups tested. Patterns of cytokine/chemokine expression in the CNS reveal characteristics of the host innate response that provide insight into the disease process and potential targets for therapeutic intervention

    Magnetic field resistant quantum interferences in bismuth nanowires based Josephson junctions

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    We investigate proximity induced superconductivity in micrometer-long bismuth nanowires con- nected to superconducting electrodes with a high critical field. At low temperature we measure a supercurrent that persists in magnetic fields as high as the critical field of the electrodes (above 11 T). The critical current is also strongly modulated by the magnetic field. In certain samples we find regular, rapid SQUID-like periodic oscillations occurring up to high fields. Other samples ex- hibit less periodic but full modulations of the critical current on Tesla field scales, with field-caused extinctions of the supercurrent. These findings indicate the existence of low dimensionally, phase coherent, interfering conducting regions through the samples, with a subtle interplay between orbital and spin contributions. We relate these surprising results to the electronic properties of the surface states of bismuth, strong Rashba spin-orbit coupling, large effective g factors, and their effect on the induced superconducting correlations.Comment: 5 page

    The role of asymmetric interactions on the effect of habitat destruction in mutualistic networks

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    Plant-pollinator mutualistic networks are asymmetric in their interactions: specialist plants are pollinated by generalist animals, while generalist plants are pollinated by a broad involving specialists and generalists. It has been suggested that this asymmetric ---or disassortative--- assemblage could play an important role in determining the equal susceptibility of specialist and generalist plants under habitat destruction. At the core of the argument lies the observation that specialist plants, otherwise candidates to extinction, could cope with the disruption thanks to their interaction with generalist pollinators. We present a theoretical framework that supports this thesis. We analyze a dynamical model of a system of mutualistic plants and pollinators, subject to the destruction of their habitat. We analyze and compare two families of interaction topologies, ranging from highly assortative to highly disassortative ones, as well as real pollination networks. We found that several features observed in natural systems are predicted by the mathematical model. First, there is a tendency to increase the asymmetry of the network as a result of the extinctions. Second, an entropy measure of the differential susceptibility to extinction of specialist and generalist species show that they tend to balance when the network is disassortative. Finally, the disappearance of links in the network, as a result of extinctions, shows that specialist plants preserve more connections than the corresponding plants in an assortative system, enabling them to resist the disruption.Comment: 14 pages, 7 figure

    A minimal model for congestion phenomena on complex networks

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    We study a minimal model of traffic flows in complex networks, simple enough to get analytical results, but with a very rich phenomenology, presenting continuous, discontinuous as well as hybrid phase transitions between a free-flow phase and a congested phase, critical points and different scaling behaviors in the system size. It consists of random walkers on a queueing network with one-range repulsion, where particles can be destroyed only if they can move. We focus on the dependence on the topology as well as on the level of traffic control. We are able to obtain transition curves and phase diagrams at analytical level for the ensemble of uncorrelated networks and numerically for single instances. We find that traffic control improves global performance, enlarging the free-flow region in parameter space only in heterogeneous networks. Traffic control introduces non-linear effects and, beyond a critical strength, may trigger the appearance of a congested phase in a discontinuous manner. The model also reproduces the cross-over in the scaling of traffic fluctuations empirically observed in the Internet, and moreover, a conserved version can reproduce qualitatively some stylized facts of traffic in transportation networks

    Correlating the nanostructure and electronic properties of InAs nanowires

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    The electronic properties and nanostructure of InAs nanowires are correlated by creating multiple field effect transistors (FETs) on nanowires grown to have low and high defect density segments. 4.2 K carrier mobilities are ~4X larger in the nominally defect-free segments of the wire. We also find that dark field optical intensity is correlated with the mobility, suggesting a simple route for selecting wires with a low defect density. At low temperatures, FETs fabricated on high defect density segments of InAs nanowires showed transport properties consistent with single electron charging, even on devices with low resistance ohmic contacts. The charging energies obtained suggest quantum dot formation at defects in the wires. These results reinforce the importance of controlling the defect density in order to produce high quality electrical and optical devices using InAs nanowires.Comment: Related papers at http://pettagroup.princeton.ed

    Human Parechovirus and Enterovirus Initiate Divergent Innate Immune Responses in the CNS: Pathogenic and Diagnostic Implications

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    The picornaviruses human parechovirus (HPeV) and enterovirus (EV) cause a wide range of diseases, including CNS infections, which can be severe and potentially fatal. EV causes most cases of pediatric meningoencephalitis worldwide, and HPeV type 3 (HPeV3) is the most common cause of viral meningitis in young infants. Each year in the United States, there are over 75,000 cases of aseptic meningitis. Despite reassuring short-term outcomes, negative neurodevelopmental sequalae are increasingly associated with HPeV and EV. The pathogenesis and severity of HPeV and EV infections are undoubtedly linked to the innate and adaptive immune responses elicited by these viruses. Until this work, the innate immune response mounted against HPeV was largely unknown. Pattern recognition receptors in the CNS, including a number of Toll-like receptors located in different cells and subcellular compartments, detect invading pathogens and cause the release of cytokines and chemokines almost immediately into the CSF compartment at measurable levels. Essentially, this allows for determination of an amplified, infectious agent-specific pattern. These virus specific patterns of innate immune activation may provide insight into the pathogenesis of the corresponding disease states. Also, since these infections have similar clinical presentations, the immune profiles may be useful for rapid pathogen diagnosis in the clinical setting
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