148 research outputs found
Magnetic Hyperthermia and Radiation Therapy : Radiobiological Principles and Current Practice
Hyperthermia, though by itself generally non-curative for cancer, can significantly increase the efficacy of radiation therapy, as demonstrated by in vitro, in vivo, and clinical results. Its limited use in the clinic is mainly due to various practical implementation difficulties, the most important being how to adequately heat the tumor, especially deep-seated ones. In this work, we first review the effects of hyperthermia on tissue, the limitations of radiation therapy and the radiobiological rationale for combining the two treatment modalities. Subsequently, we review the theory and evidence for magnetic hyperthermia that is based on magnetic nanoparticles, its advantages compared with other methods of hyperthermia, and how it can be used to overcome the problems associated with traditional techniques of hyperthermia
VirtuWind: Virtual and Programmable Industrial Network Prototype Deployed in Operational Wind Park
With anticipated exponential growth of connected
devices, future industrial networks require an open solutions architecture facilitated by standards and a strong ecosystem.VirtuWind aims to develop and demonstrate an SDN and NFV ecosystem, based on an open, modular and secure framework.A prototype of the framework for intra-domain and inter-domain scenarios will be showcased in real wind parks,as a representative use case of industrial networks. Validate the economic viability of the demonstrated solution is paramount for VirtuWind.
This paper details this vision and explains steps forward
Incorporation of realistic delivery limitations into dynamic MLC treatment delivery
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135102/1/mp0499.pd
Curling: Content-ubiquitous resolution and delivery infrastructure for next-generation services
CURLING, a Content-Ubiquitous Resolution and Delivery Infrastructure for Next Generation Services, aims to enable a future content-centric Internet that will overcome the current intrinsic constraints by efficiently diffusing media content of massive scale. It entails a holistic approach, supporting content manipulation capabilities that encompass the entire content life cycle, from content publication to content resolution and, finally, to content delivery. CURLING provides to both content providers and customers high flexibility in expressing their location preferences when publishing and requesting content, respectively, thanks to the proposed scoping and filtering functions. Content manipulation operations can be driven by a variety of factors, including business relationships between ISPs, local ISP policies, and specific content provider and customer preferences. Content resolution is also natively coupled with optimized content routing techniques that enable efficient unicast and multicast-based content delivery across the global Internet
Heterogeneous Ca2+ influx along the adult calyx of held: A structural and computational study
The calyx of Held is a morphologically complex nerve terminal containing hundreds to thousands of active zones. The calyx must support high rates of transient, sound-evoked vesicular release superimposed on a background of sustained release, due to the high spontaneous rates of some afferent fibers. One means of distributing vesicle release in space and time is to have heterogeneous release probabilities (Pr) at distinct active zones, which has been observed at several CNS synapses including the calyx of Held. Pr may be modulated by vesicle proximity to Ca2+ channels, by Ca2+ buffers, by changes in phosphorylation state of proteins involved in the release process, or by local variations in Ca2+ influx. In this study, we explore the idea that the complex geometry of the calyx also contributes to heterogeneous Pr by impeding equal propagation of action potentials through all calyx compartments. Given the difficulty of probing ion channel distribution and recording from adult calyces, we undertook a structural and modeling approach based on computerized reconstructions of calyces labeled in adult cats. We were thus able to manipulate placement of conductances and test their effects on Ca2+ concentration in all regions of the calyx following an evoked action potential in the calyceal axon. Our results indicate that with a non-uniform distribution of Na+ and K+ channels, action potentials do not propagate uniformly into the calyx, Ca2+ influx varies across different release sites, and latency for these events varies among calyx compartments. We suggest that the electrotonic structure of the calyx of Held, which our modeling efforts indicate is very sensitive to the axial resistivity of cytoplasm, may contribute to variations in release probability within the calyx
Algorithm and performance of a clinical IMRT beam-angle optimization system
This paper describes the algorithm and examines the performance of an IMRT
beam-angle optimization (BAO) system. In this algorithm successive sets of beam
angles are selected from a set of predefined directions using a fast simulated
annealing (FSA) algorithm. An IMRT beam-profile optimization is performed on
each generated set of beams. The IMRT optimization is accelerated by using a
fast dose calculation method that utilizes a precomputed dose kernel. A compact
kernel is constructed for each of the predefined beams prior to starting the
FSA algorithm. The IMRT optimizations during the BAO are then performed using
these kernels in a fast dose calculation engine. This technique allows the IMRT
optimization to be performed more than two orders of magnitude faster than a
similar optimization that uses a convolution dose calculation engine.Comment: Final version that appeared in Phys. Med. Biol. 48 (2003) 3191-3212.
Original EPS figures have been converted to PNG files due to size limi
SARDANA: an all-optical access-metro WDM/TDM-PON
A new optical access network, named âScalable Advanced Ring-based passive Dense Access Network
Architectureâ (SARDANA), is presented. It transparently integrates WDM metro and TDM PON access
technologies, implementing ring protection, 100 km reach and up to 1024 users served at 10 Gb/s, with
passive highly-shared infrastructure. The introduced innovations are hybrid ring/tree WDM/TDM Passive
Optical Network (PON) architecture; a resilient remote node (RN), which is distantly pumped from the
Optical Line Terminal (OLT); and a reflective ONU (Optical Network Unit); as well as an enhanced
Medium Access Control (MAC) protocol.Postprint (published version
World-leading science with SPIRou - the nIR spectropolarimeter / high-precision velocimeter for CFHT
SPIRou is a near-infrared (nIR) spectropolarimeter / velocimeter proposed as
a new-generation instrument for CFHT. SPIRou aims in particular at becoming
world-leader on two forefront science topics, (i) the quest for habitable
Earth-like planets around very- low-mass stars, and (ii) the study of low-mass
star and planet formation in the presence of magnetic fields. In addition to
these two main goals, SPIRou will be able to tackle many key programs, from
weather patterns on brown dwarf to solar-system planet atmospheres, to dynamo
processes in fully-convective bodies and planet habitability. The science
programs that SPIRou proposes to tackle are forefront (identified as first
priorities by most research agencies worldwide), ambitious (competitive and
complementary with science programs carried out on much larger facilities, such
as ALMA and JWST) and timely (ideally phased with complementary space missions
like TESS and CHEOPS).
SPIRou is designed to carry out its science mission with maximum efficiency
and optimum precision. More specifically, SPIRou will be able to cover a very
wide single-shot nIR spectral domain (0.98-2.35 \mu m) at a resolving power of
73.5K, providing unpolarized and polarized spectra of low-mass stars with a
~15% average throughput and a radial velocity (RV) precision of 1 m/s.Comment: 12 pages, 5 figures, conference proceedings of the French Society of
Astronomy and Astrophysics meeting 201
Recommendations for In Vitro and In Vivo Testing of Magnetic Nanoparticle Hyperthermia Combined with Radiation Therapy
Magnetic nanoparticle (MNP)-mediated hyperthermia (MH) coupled with radiation therapy (RT) is a novel approach that has the potential to overcome various practical difficulties encountered in cancer treatment. In this work, we present recommendations for the in vitro and in vivo testing and application of the two treatment techniques. These recommendations were developed by the members of Working Group 3 of COST Action TD 1402: Multifunctional Nanoparticles for Magnetic Hyperthermia and Indirect Radiation Therapy (âRadiomagâ). The purpose of the recommendations is not to provide definitive answers and directions but, rather, to outline those tests and considerations that a researcher must address in order to perform in vitro and in vivo studies. The recommendations are divided into 5 parts: (a) in vitro evaluation of MNPs; (b) in vitro evaluation of MNP-cell interactions; (c) in vivo evaluation of the MNPs; (d) MH combined with RT; and (e) pharmacokinetic studies of MNPs. Synthesis and characterization of the MNPs, as well as RT protocols, are beyond the scope of this wor
Stable accretion and episodic outflows in the young transition disk system GM Aurigae
We investigate the structure and dynamics of the magnetospheric accretion
region and associated outflows on a scale smaller than 0.1 au around the young
transitional disk system GM Aur. We monitored the variability of the system on
timescales ranging from days to months, using high-resolution optical and
near-infrared spectroscopy, multiwavelength photometry, and low-resolution
near-infrared spectroscopy, over a total duration of six months (30 rotational
cycles). We analyzed the photometric and line profile variability to
characterize the accretion and ejection processes. The luminosity of the system
is modulated by surface spots at the stellar rotation period of 6.04 days. The
Balmer, Paschen, and Brackett hydrogen lines as well as the HeI 5876 A and HeI
10830 A line profiles are modulated on the same period. The PaB line flux
correlates with the photometric excess in the u' band, which suggests that most
of the line emission originates from the accretion process. High-velocity
redshifted absorptions reaching below the continuum periodically appear in the
near-infrared line profiles at the rotational phase in which the veiling and
line fluxes are the largest. These are signatures of a stable accretion funnel
flow and associated accretion shock at the stellar surface. This large-scale
magnetospheric accretion structure appears fairly stable over at least 15 and
possibly up to 30 rotational periods. In contrast, outflow signatures randomly
appear as blueshifted absorption components in the Balmer and HeI 10830 A line
profiles and disappear on a timescale of a few days. The coexistence of a
stable, large-scale accretion pattern and episodic outflows supports
magnetospheric ejections as the main process occurring at the star-disk
interface. Stable magnetospheric accretion and episodic outflows appear to be
physically linked on a scale of a few stellar radii in this system.Comment: 30 pages, 28 figures, 12 tables, accepted for publication in
Astronomy & Astrophysic
- âŠ