9,564 research outputs found
Particle acceleration and the origin of gamma-ray emission from Fermi Bubbles
Fermi LAT has discovered two extended gamma-ray bubbles above and below the
galactic plane. We propose that their origin is due to the energy release in
the Galactic center (GC) as a result of quasi-periodic star accretion onto the
central black hole. Shocks generated by these processes propagate into the
Galactic halo and accelerate particles there. We show that electrons
accelerated up to ~10 TeV may be responsible for the observed gamma-ray
emission of the bubbles as a result of inverse Compton (IC) scattering on the
relic photons. We also suggest that the Bubble could generate the flux of CR
protons at energies > 10^15 eV because the shocks in the Bubble have much
larger length scales and longer lifetimes in comparison with those in SNRs.
This may explain the the CR spectrum above the knee.Comment: 5 pages, 4 figures. Expanded version of the contribution to the 32nd
ICRC, Beijing, #0589. To appear in the proceeding
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Different WDR36 Mutation Pattern in Chinese Patients with Primary Open-angle Glaucoma
Purpose: To determine the distribution of WD repeat domain 36 (WDR36) sequence variants in Chinese patients with primary open-angle glaucoma (POAG). Methods: One hundred and thirty-five unrelated POAG patients (82 high tension glaucoma [HTG], 42 normal tension glaucoma [NTG], and 11 juvenile-onset POAG [JOAG] patients) and 77 unrelated controls were recruited. All 23 coding exons and splicing junctions of WDR36 were sequenced using BigDye® Terminator v3.1 cycle sequencing kit. Single nucleotide polymorphism (SNP) and haplotype associations were analyzed using PLINK (version 1.04). Results: Nineteen sequence alterations were identified, and eight of them were novel including two novel nonsynonymous SNPs (L240V and I713V). Except the common I264V polymorphism, no other previously reported disease-causing or disease-susceptibility mutations were found. The novel I713V mutation was observed in three (3.7%) patients with HTG. One intronic SNP, IVS5+30C>T (rs10038177), showed significantly higher frequency of minor allele T in HTG patients (16.5%) than in controls (1.3%; Odds ratio [OR]=15.0, p=7.9×10−7, Bonferroni corrected p=1.5×10−5). Haplotype GTA, which is composed of rs13153937, rs10038177, and rs11241095, was significantly associated with HTG (OR=22.5, p=0.002, Bonferroni corrected p=0.013). Neither the individual SNPs nor haplotypes of WDR36 were associated with NTG or JOAG (Bonferroni corrected p>0.05). Conclusions: Findings in this study suggest WDR36 to be associated with sporadic HTG but not with NTG or JOAG. Our results also suggest a different mutation pattern of WDR36 in the Chinese population from other ethnic populations
Image operator learning coupled with CNN classification and its application to staff line removal
Many image transformations can be modeled by image operators that are
characterized by pixel-wise local functions defined on a finite support window.
In image operator learning, these functions are estimated from training data
using machine learning techniques. Input size is usually a critical issue when
using learning algorithms, and it limits the size of practicable windows. We
propose the use of convolutional neural networks (CNNs) to overcome this
limitation. The problem of removing staff-lines in music score images is chosen
to evaluate the effects of window and convolutional mask sizes on the learned
image operator performance. Results show that the CNN based solution
outperforms previous ones obtained using conventional learning algorithms or
heuristic algorithms, indicating the potential of CNNs as base classifiers in
image operator learning. The implementations will be made available on the
TRIOSlib project site.Comment: To appear in ICDAR 201
Developing an EEG-based on-line closed-loop lapse detection and mitigation system
© 2014 Wang, Huang, Wei, Huang, Ko, Lin, Cheng and Jung. In America, 60% of adults reported that they have driven a motor vehicle while feeling drowsy, and at least 15-20% of fatal car accidents are fatigue-related. This study translates previous laboratory-oriented neurophysiological research to design, develop, and test an On-line Closed-loop Lapse Detection and Mitigation (OCLDM) System featuring a mobile wireless dry-sensor EEG headgear and a cell-phone based real-time EEG processing platform. Eleven subjects participated in an event-related lane-keeping task, in which they were instructed to manipulate a randomly deviated, fixed-speed cruising car on a 4-lane highway. This was simulated in a 1st person view with an 8-screen and 8-projector immersive virtual-reality environment. When the subjects experienced lapses or failed to respond to events during the experiment, auditory warning was delivered to rectify the performance decrements. However, the arousing auditory signals were not always effective. The EEG spectra exhibited statistically significant differences between effective and ineffective arousing signals, suggesting that EEG spectra could be used as a countermeasure of the efficacy of arousing signals. In this on-line pilot study, the proposed OCLDM System was able to continuously detect EEG signatures of fatigue, deliver arousing warning to subjects suffering momentary cognitive lapses, and assess the efficacy of the warning in near real-time to rectify cognitive lapses. The on-line testing results of the OCLDM System validated the efficacy of the arousing signals in improving subjects' response times to the subsequent lane-departure events. This study may lead to a practical on-line lapse detection and mitigation system in real-world environments
Ileocecal Burkitt's Lymphoma Presenting as Ileocolic Intussusception With Appendiceal Invagination and Acute Appendicitis
Intussusception is a common cause of abdominal pain in children. Although most cases are idiopathic, about 10% of cases have a pathologic lead point. Burkitt's lymphoma is not a common etiology. Burkitt's lymphoma might present primarily as intussusception in children but has rarely been associated with appendicitis. We report a case in which a 10-year-old obese boy who initially presented with acute appendicitis due to ileocolic intussusception with appendiceal invagination. He underwent one-trocar laparoscopy and antibiotic treatment. The symptoms recurred 10 days after discharge. Colonoscopy disclosed ileocecal Burkitt's lymphoma as the pathological lead point. This case emphasizes the importance of the age of the patient and the anatomic location of the intussusception related to possible etiology, and hence the most appropriate surgical procedure
Probing the DNA kink structure induced by the hyperthermophilic chromosomal protein Sac7d
Sac7d, a small, abundant, sequence-general DNA-binding protein from the hyperthermophilic archaeon Sulfolobus acidocaldarius, causes a single-step sharp kink in DNA (∼60°) via the intercalation of both Val26 and Met29. These two amino acids were systematically changed in size to probe their effects on DNA kinking. Eight crystal structures of five Sac7d mutant–DNA complexes have been analyzed. The DNA-binding pattern of the V26A and M29A single mutants is similar to that of the wild-type, whereas the V26A/M29A protein binds DNA without side chain intercalation, resulting in a smaller overall bending (∼50°). The M29F mutant inserts the Phe29 side chain orthogonally to the C2pG3 step without stacking with base pairs, inducing a sharp kink (∼80°). In the V26F/M29F-GCGATCGC complex, Phe26 intercalates deeply into DNA bases by stacking with the G3 base, whereas Phe29 is stacked on the G15 deoxyribose, in a way similar to those used by the TATA box-binding proteins. All mutants have reduced DNA-stabilizing ability, as indicated by their lower T(m) values. The DNA kink patterns caused by different combinations of hydrophobic side chains may be relevant in understanding the manner by which other minor groove-binding proteins interact with DNA
Hesperetin-7,3'-O-dimethylether selectively inhibits phosphodiesterase 4 and effectively suppresses ovalbumin-induced airway hyperresponsiveness with a high therapeutic ratio
<p>Abstract</p> <p>Background</p> <p>Hesperetin was reported to selectively inhibit phosphodiesterase 4 (PDE4). While hesperetin-7,3'-<it>O</it>-dimethylether (HDME) is a synthetic liposoluble hesperetin. Therefore, we were interested in investigating its selectivity on PDE4 and binding ability on high-affinity rolipram-binding sites (HARBs) <it>in vitro</it>, and its effects on ovalbumin-induced airway hyperresponsiveness <it>in vivo</it>, and clarifying its potential for treating asthma and chronic obstructive pulmonary disease (COPD).</p> <p>Methods</p> <p>PDE1~5 activities were measured using a two-step procedure. The binding of HDME on high-affinity rolipram-binding sites was determined by replacing 2 nM [<sup>3</sup><it>H</it>]-rolipram. AHR was assessed using the FlexiVent system and barometric plethysmography. Inflammatory cells were counted using a hemocytometer. Cytokines were determined using mouse T helper (Th)1/Th2 cytokine CBA kits, and total immunoglobulin (Ig)E or IgG<sub>2a </sub>levels were done using ELISA method. Xylazine (10 mg/kg)/ketamine (70 mg/kg)-induced anesthesia was performed.</p> <p>Results</p> <p>HDME revealed selective phosphodiesterase 4 (PDE4) inhibition with a therapeutic (PDE4<sub>H</sub>/PDE4<sub>L</sub>) ratio of 35.5 <it>in vitro</it>. <it>In vivo</it>, HDME (3~30 μmol/kg, orally (p.o.)) dose-dependently and significantly attenuated the airway resistance (R<sub>L</sub>) and increased lung dynamic compliance (C<sub>dyn</sub>), and decreased enhanced pause (P<sub>enh</sub>) values induced by methacholine in sensitized and challenged mice. It also significantly suppressed the increases in the numbers of total inflammatory cells, macrophages, lymphocytes, neutrophils, and eosinophils, and levels of cytokines, including interleukin (IL)-2, IL-4, IL-5, interferon-γ, and tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF) of these mice. In addition, HDME (3~30 μmol/kg, p.o.) dose-dependently and significantly suppressed total and ovalbumin-specific immunoglobulin (Ig)E levels in the BALF and serum, and enhanced IgG<sub>2a </sub>level in the serum of these mice.</p> <p>Conclusions</p> <p>HDME exerted anti-inflammatory effects, including suppression of AHR, and reduced expressions of inflammatory cells and cytokines in this murine model, which appears to be suitable for studying the effects of drugs on atypical asthma and COPD, and for screening those on typical asthma. However, HDME did not influnce xylazine/ketamine-induced anesthesia. Thus HDME may have the potential for use in treating typical and atypical asthma, and COPD.</p
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