2,105 research outputs found
Dermoscopy and methyl aminolevulinate: A study for detection and evaluation of field cancerization
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
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
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
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
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
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
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
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
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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