3,054 research outputs found
Near-infrared spectroscopy as a tool for in vivo analysis of human muscles
Recent advances in materials and fabrication techniques provided portable, performant, sensing optical spectrometers readily operated by user-friendly cabled or wireless systems. Such systems allow rapid, non-invasive, and not destructive quantitative analysis of human tissues. This proof-of-principle investigation tested whether infrared spectroscopy techniques, currently utilized in a variety of areas, could be applied in living humans to categorize muscles. Using an ASD FieldSpec\uae 4 Standard-Res Spectroradiometer with a spectral sampling capability of 1.4 nm at 350\u20131000 nm and 1.1 nm at 1001\u20132500 nm, we acquired reflectance spectra in visible short-wave infra-red regions (350\u20132500 nm) from the upper limb muscles (flexors and extensors) of 20 healthy subjects (age 25\u201389 years, 9 women). Spectra off-line analysis included preliminary preprocessing, Principal Component Analysis, and Partial Least-Squares Discriminant Analysis. Near-infrared (NIR) spectroscopy proved valuable for noninvasive assessment of tissue optical properties in vivo. In addition to the non-invasive detection of tissue oxygenation, NIR spectroscopy provided the spectral signatures (ie, \u201cfingerprints\u201d) of upper limb flexors and extensors, which represent specific, accurate, and reproducible measures of the overall biological status of these muscles. Thus, non-invasive NIR spectroscopy enables more thorough evaluation of the muscular system and optimal monitoring of the effectiveness of therapeutic or rehabilitative interventions
Giant Solitary Fibrous Tumor of the Pleura: An Analysis of Five Patients
Ó The Author(s) 2010. This article is published with open access at Springerlink.com Background Solitary fibrous tumor of the pleura (SFTP) represents a clinical entity rarely encountered, especially in giant forms. Complete surgical resection for giant tumor of pleura is a challenge. The aim of this article is to present five new cases of giant SFTP, and to discuss their clinical characteristics and the treatment strategy of such neoplasms. Methods We performed a retrospective review of the clinical records of five patients who underwent surgery for a huge SFTP ([18 cm in diameter) between 2007 and 2009. Results Four patients were symptomatic. All five patients underwent angiography and embolization of the tumorsupplying vessels within 24 h of surgery. All giant tumors were removed completely by extended postlateral thoracotomy with moderate intraoperative bleeding. Two wedge resections and one lobectomy were performed in three cases where the parenchyma had been encroached. Tumors in three patients were pathologically benign; those in the other two were malignant. The symptoms disappeared in all cases after surgery. Conclusions Complete resection remains the mainstay of cure for giant SFTP. We recommend preoperative angiography and embolization for giant SFTP which can reduce the risk of hemorrhage and can contribute to piecemeal removal for radical excision
Neutral pion emission from accelerated protons in the supernova remnant W44
We present the AGILE gamma-ray observations in the energy range 50 MeV - 10
GeV of the supernova remnant (SNR) W44, one of the most interesting systems for
studying cosmic-ray production. W44 is an intermediate-age SNR (20, 000 years)
and its ejecta expand in a dense medium as shown by a prominent radio shell,
nearby molecular clouds, and bright [SII] emitting regions. We extend our
gamma-ray analysis to energies substantially lower than previous measurements
which could not conclusively establish the nature of the radiation. We find
that gamma-ray emission matches remarkably well both the position and shape of
the inner SNR shocked plasma. Furthermore, the gamma-ray spectrum shows a
prominent peak near 1 GeV with a clear decrement at energies below a few
hundreds of MeV as expected from neutral pion decay. Here we demonstrate that:
(1) hadron-dominated models are consistent with all W44 multiwavelength
constraints derived from radio, optical, X-ray, and gamma-ray observations; (2)
ad hoc lepton-dominated models fail to explain simultaneously the
well-constrained gamma-ray and radio spectra, and require a circumstellar
density much larger than the value derived from observations; (3) the hadron
energy spectrum is well described by a power-law (with index s = 3.0 \pm 0.1)
and a low-energy cut-off at Ec = 6 \pm 1 GeV. Direct evidence for pion emission
is then established in an SNR for the first time.Comment: accepted for publication on ApJ
Epidemics in partially overlapped multiplex networks
Many real networks exhibit a layered structure in which links in each layer
reflect the function of nodes on different environments. These multiple types
of links are usually represented by a multiplex network in which each layer has
a different topology. In real-world networks, however, not all nodes are
present on every layer. To generate a more realistic scenario, we use a
generalized multiplex network and assume that only a fraction of the nodes
are shared by the layers. We develop a theoretical framework for a branching
process to describe the spread of an epidemic on these partially overlapped
multiplex networks. This allows us to obtain the fraction of infected
individuals as a function of the effective probability that the disease will be
transmitted . We also theoretically determine the dependence of the epidemic
threshold on the fraction of shared nodes in a system composed of two
layers. We find that in the limit of the threshold is dominated by
the layer with the smaller isolated threshold. Although a system of two
completely isolated networks is nearly indistinguishable from a system of two
networks that share just a few nodes, we find that the presence of these few
shared nodes causes the epidemic threshold of the isolated network with the
lower propagating capacity to change discontinuously and to acquire the
threshold of the other network.Comment: 13 pages, 4 figure
Imaging of SNR IC443 and W44 with the Sardinia Radio Telescope at 1.5 GHz and 7 GHz
Observations of supernova remnants (SNRs) are a powerful tool for
investigating the later stages of stellar evolution, the properties of the
ambient interstellar medium, and the physics of particle acceleration and
shocks. For a fraction of SNRs, multi-wavelength coverage from radio to ultra
high-energies has been provided, constraining their contributions to the
production of Galactic cosmic rays. Although radio emission is the most common
identifier of SNRs and a prime probe for refining models, high-resolution
images at frequencies above 5 GHz are surprisingly lacking, even for bright and
well-known SNRs such as IC443 and W44. In the frameworks of the Astronomical
Validation and Early Science Program with the 64-m single-dish Sardinia Radio
Telescope, we provided, for the first time, single-dish deep imaging at 7 GHz
of the IC443 and W44 complexes coupled with spatially-resolved spectra in the
1.5-7 GHz frequency range. Our images were obtained through on-the-fly mapping
techniques, providing antenna beam oversampling and resulting in accurate
continuum flux density measurements. The integrated flux densities associated
with IC443 are S_1.5GHz = 134 +/- 4 Jy and S_7GHz = 67 +/- 3 Jy. For W44, we
measured total flux densities of S_1.5GHz = 214 +/- 6 Jy and S_7GHz = 94 +/- 4
Jy. Spectral index maps provide evidence of a wide physical parameter scatter
among different SNR regions: a flat spectrum is observed from the brightest SNR
regions at the shock, while steeper spectral indices (up to 0.7) are observed
in fainter cooling regions, disentangling in this way different populations and
spectra of radio/gamma-ray-emitting electrons in these SNRs.Comment: 13 pages, 9 figures, accepted for publication to MNRAS on 18 May 201
Pegaso: an ultra-light long duration stratospheric payload for polar regions flights
Stratospheric balloons are powerful and affordable tools for a wide spectrum of scientific investigations that are carried out at the stratosphere level. They are less expensive compared to satellite projects and have the capability to lift payloads from a few kilograms to a couple of tons or more, well above the troposphere, for more than a month. Another interesting feature of these balloons, which is not viable in satellites, is the short turnaround time, which enables frequent flights. We introduce the PEGASO (Polar Explorer for Geomagnetism And other Scientific Observations) project, a stratospheric payload designed and developed by the INGV (Istituto Nazionale di Geofisica e Vulcanologia), Rome and La Sapienza University, Rome. The project was sponsored by the PNRA (Progetto Nazionale di Ricerche in Antartide), Italy (Peterzen et al., 2003). This light payload (10 kg) was used by the Italian Space Agency (ASI) and Andoya Rocket Range (ARR) for five different scientific missions. PEGASO carries a 3-component flux-gate magnetometer, uses a solar cell array as the power source and has a GPS location system. The bi-directional telemetry system for data transfer and the remote control system were IRIDIUM basedINGV, PNRA, ASI, ARR, CNR, La SapienzaPublishedBeijing, China1.10. TTC - Telerilevamentoope
AGILE Observations of the Gravitational Wave Event GW150914
We report the results of an extensive search in the AGILE data for a
gamma-ray counterpart of the LIGO gravitational wave event GW150914. Currently
in spinning mode, AGILE has the potential of covering with its gamma-ray
instrument 80 % of the sky more than 100 times a day. It turns out that AGILE
came within a minute from the event time of observing the accessible GW150914
localization region. Interestingly, the gamma-ray detector exposed about 65 %
of this region during the 100 s time intervals centered at -100 s and +300 s
from the event time. We determine a 2-sigma flux upper limit in the band 50 MeV
- 10 GeV, obtained
about 300 s after the event. The timing of this measurement is the fastest ever
obtained for GW150914, and significantly constrains the electromagnetic
emission of a possible high-energy counterpart. We also carried out a search
for a gamma-ray precursor and delayed emission over timescales ranging from
minutes to days: in particular, we obtained an optimal exposure during the
interval -150 / -30 s. In all these observations, we do not detect a
significant signal associated with GW150914. We do not reveal the weak
transient source reported by Fermi-GBM 0.4 s after the event time. However,
even though a gamma-ray counterpart of the GW150914 event was not detected, the
prospects for future AGILE observations of gravitational wave sources are
decidedly promising.Comment: 20 pages, 6 figures. Submitted to the Astrophysical Journal Letters
on April 1, 201
Free-amino acid metabolic profiling of visceral adipose tissue from obese subjects
Interest in adipose tissue pathophysiology and biochemistry have expanded considerably in the past two decades due to the ever increasing and alarming rates of global obesity and its critical outcome defined as metabolic syndrome (MS). This obesity-linked systemic dysfunction generates high risk factors of developing perilous diseases like type 2 diabetes, cardiovascular disease or cancer. Amino acids could play a crucial role in the pathophysiology of the MS onset. Focus of this study was to fully characterize amino acids metabolome modulations in visceral adipose tissues (VAT) from three adult cohorts: (i) obese patients (BMI 43-48) with metabolic syndrome (PO), (ii) obese subjects metabolically well (O), and (iii) non obese individuals (H). 128 metabolites identified as 20 protein amino acids, 85 related compounds and 13 dipeptides were measured by ultrahigh performance liquid chromatography-tandem mass spectroscopy (UPLC-MS/MS) and gas chromatography-/mass spectrometry GC/MS, in visceral fat samples from a total of 53 patients. Our analysis indicates a probable enhanced BCAA (leucine, isoleucine, valine) degradation in both VAT from O and PO subjects, while levels of their oxidation products are increased. Also PO and O VAT samples were characterized by: elevated levels of kynurenine, a catabolic product of tryptophan and precursor of diabetogenic substances, a significant increase of cysteine sulfinic acid levels, a decrease of 1-methylhistidine, and an up regulating trend of 3-methylhistidine levels. We hope this profiling can aid in novel clinical strategies development against the progression from obesity to metabolic syndrome
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