29,774 research outputs found
New line-interactive UPS system with DSP-based active power-line conditioning
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On the constrained KP hierarchy
An explanation for the so-called constrained hierarhies is presented by
linking them with the symmetries of the KP hierarchy. While the existence of
ordinary symmetries (belonging to the hierarchy) allows one to reduce the KP
hierarchy to the KdV hierarchies, the existence of additional symmetries allows
to reduce KP to the constrained KP.Comment: 7pp, LaTe
Improved real-time imaging spectrometer
An improved AOTF-based imaging spectrometer that offers several advantages over prior art AOTF imaging spectrometers is presented. The ability to electronically set the bandpass wavelength provides observational flexibility. Various improvements in optical architecture provide simplified magnification variability, improved image resolution and light throughput efficiency and reduced sensitivity to ambient light. Two embodiments of the invention are: (1) operation in the visible/near-infrared domain of wavelength range 0.48 to 0.76 microns; and (2) infrared configuration which operates in the wavelength range of 1.2 to 2.5 microns
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FAM129B, an antioxidative protein, reduces chemosensitivity by competing with Nrf2 for Keap1 binding.
BackgroundThe transcription factor Nrf2 is a master regulator of antioxidant response. While Nrf2 activation may counter increasing oxidative stress in aging, its activation in cancer can promote cancer progression and metastasis, and confer resistance to chemotherapy and radiotherapy. Thus, Nrf2 has been considered as a key pharmacological target. Unfortunately, there are no specific Nrf2 inhibitors for therapeutic application. Moreover, high Nrf2 activity in many tumors without Keap1 or Nrf2 mutations suggests that alternative mechanisms of Nrf2 regulation exist.MethodsInteraction of FAM129B with Keap1 is demonstrated by immunofluorescence, colocalization, co-immunoprecipitation and mammalian two-hybrid assay. Antioxidative function of FAM129B is analyzed by measuring ROS levels with DCF/flow cytometry, Nrf2 activation using luciferase reporter assay and determination of downstream gene expression by qPCR and wester blotting. Impact of FAM129B on in vivo chemosensitivity is examined in mice bearing breast and colon cancer xenografts. The clinical relevance of FAM129B is assessed by qPCR in breast cancer samples and data mining of publicly available databases.FindingsWe have demonstrated that FAM129B in cancer promotes Nrf2 activity by reducing its ubiquitination through competition with Nrf2 for Keap1 binding via its DLG and ETGE motifs. In addition, FAM129B reduces chemosensitivity by augmenting Nrf2 antioxidative signaling and confers poor prognosis in breast and lung cancer.InterpretationThese findings demonstrate the important role of FAM129B in Nrf2 activation and antioxidative response, and identify FMA129B as a potential therapeutic target. FUND: The Chang Gung Medical Foundation (Taiwan) and the Ministry of Science and Technology (Taiwan)
Use of FBG optical sensors for structural health monitoring: Practical application
This paper describes the development of FBG Optical sensors for their practical application on structural health monitoring. The sensors were installed on the Tsing Ma Bridge for a trial run. The results using FBG sensors were in excellent agreement with those acquired by the bridge WASHMS
XOR multiplexing technique for nanocomputers
In emerging nanotechnologies, due to the manufacturing process, a significant percentage of components may be faulty. In order to make systems based on unreliable nano-scale components reliable, it is necessary to design fault-tolerant architectures. This paper presents a novel fault-tolerant technique for nanocomputers, namely the XOR multiplexing technique. This hardware redundancy technique is based on a numerous duplication of faulty components. We analyze the error distributions of the XOR multiplexing unit and the error distributions of multiple stages of the XOR multiplexing system, then compare them to the NAND multiplexing unit and the NAND multiplexing multiple stages system, respectively. The simulation results show that XOR multiplexing is more reliable than NAND multiplexing. Bifurcation theory is used to analyze the fault-tolerant ability of the system and the results show that XOR multiplexing technique has a high fault-tolerant ability. Similarly to the NAND multiplexing technique, this fault-tolerant technique is a potentially effective fault tolerant technique for future nanoelectronics
On Goldstone bosons decoupling from high-lying hadrons
In this paper, we discuss a decoupling of the Goldstone bosons from highly
excited hadrons in relation to the restoration of chiral symmetry in such
hadrons. We use a generalised Nambu-Jona-Lasinio model with the interaction
between quarks in the form of an instantaneous Lorentz-vector confining
potential. This model is known to provide spontaneous breaking of chiral
symmetry in the vacuum via the standard selfenergy loops for valence quarks.
For highly excited hadrons, where the typical momentum of valence quarks is
large, the loop contributions represent only a small correction to the
chiral-invariant classical contributions and asymptotically vanish.
Consequently the chiral symmetry violating Lorentz-scalar dynamical mass of
quarks vanishes. Then the conservation of the axial vector current in the
chiral limit requires, via the Goldberger-Treiman relation, that the valence
quarks decouple from the Goldstone boson. As a consequence, the whole hadron
decouples from the Goldstone boson as well, which implies that its axial
constant also vanishes.Comment: RevTeX4, 21 pages, 5 Postscript figures, uses epsfig.sty, new chapter
with numerical estimates added, to appear in Phys.Rev.
Chiral symmetry restoration in excited hadrons, quantum fluctuations, and quasiclassics
In this paper, we discuss the transition to the semiclassical regime in
excited hadrons, and consequently, the restoration of chiral symmetry for these
states. We use a generalised Nambu-Jona-Lasinio model with the interaction
between quarks in the form of the instantaneous Lorentz-vector confining
potential. This model is known to provide spontaneous breaking of chiral
symmetry in the vacuum via the standard selfenergy loops for valence quarks. It
has been shown recently that the effective single-quark potential is of the
Lorentz-scalar nature, for the low-lying hadrons, while, for the high-lying
states, it becomes a pure Lorentz vector and hence the model exhibits the
restoration of chiral symmetry. We demonstrate explicitly the quantum nature of
chiral symmetry breaking, the absence of chiral symmetry breaking in the
classical limit as well as the transition to the semiclassical regime for
excited states, where the effect of chiral symmetry breaking becomes only a
small correction to the classical contributions.Comment: RevTeX4, 20 pages, 4 Postscript figures, uses epsfig.sty, typos
correcte
Charmless Three-body Decays of B Mesons
Charmless 3-body decays of B mesons are studied in the framework of the
factorization approach. The nonresonant contributions arising from transitions are evaluated using heavy meson chiral perturbation theory
(HMChPT). The momentum dependence of nonresonant amplitudes is assumed to be in
the exponential form e^{-\alpha_{NR}} p_B\cdot(p_i+p_j)} so that the HMChPT
results are recovered in the soft meson limit . In addition, we
have identified another large source of the nonresonant signal in the matrix
elements of scalar densities, e.g. , which can be
constrained from the decay or . The
intermediate vector meson contributions to 3-body decays are identified through
the vector current, while the scalar meson resonances are mainly associated
with the scalar density. Their effects are described in terms of the
Breit-Wigner formalism. Our main results are: (i) All KKK modes are dominated
by the nonresonant background. The predicted branching ratios of
, and modes are consistent with the
data within errors. (ii) Although the penguin-dominated
decay is subject to a potentially significant tree pollution, its effective
is very similar to that of the mode. However, direct
CP asymmetry of the former, being of order -4%, is more prominent than the
latter. (iii) For decays, we found sizable nonresonant
contributions in and modes, in agreement
with the Belle measurements but larger than the BaBar result.Comment: 39 pages, 2 figures, version to appear in PR
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Neural plasticity in common forms of chronic headaches
Headaches are universal experiences and among the most common disorders. While headache may be physiological in the acute
setting, it can become a pathological and persistent condition.The mechanisms underlying the transition from episodic to chronic
pain have been the subject of intense study. Using physiological and imaging methods, researchers have identified a number of
different forms of neural plasticity associated with migraine and other headaches, including peripheral and central sensitization,
and alterations in the endogenous mechanisms of pain modulation. While these changes have been proposed to contribute to
headache and pain chronification, some findings are likely the results of repetitive noxious stimulation, such as atrophy of brain
areas involved in pain perception and modulation. In this review, we provide a narrative overview of recent advances on the
neuroimaging, electrophysiological and genetic aspects of neural plasticity associated with the most common forms of chronic
headaches, including migraine, cluster headache, tension-type headache, and medication overuse headache
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