3,217 research outputs found
Modulation Instability, Breathers, and Bound Solitons in an Erbium-Doped Fiber System with Higher-Order Effects
We mainly investigate the generalized nonlinear Schrödinger-Maxwell-Bloch system which governs the propagation of optical solitons in nonlinear erbium-doped fibers with higher-order effects. We deduce Lax pair, analyze modulation instability conditions, construct the Darboux transformation, and derive the Akhmediev breathers, Ma-breathers, bound solitons, and two-breather solutions for this system. Considering the influences of higher-order effects, propagation properties of those solitons are discussed
LE2Fusion: A novel local edge enhancement module for infrared and visible image fusion
Infrared and visible image fusion task aims to generate a fused image which
contains salient features and rich texture details from multi-source images.
However, under complex illumination conditions, few algorithms pay attention to
the edge information of local regions which is crucial for downstream tasks. To
this end, we propose a fusion network based on the local edge enhancement,
named LE2Fusion. Specifically, a local edge enhancement (LE2) module is
proposed to improve the edge information under complex illumination conditions
and preserve the essential features of image. For feature extraction, a
multi-scale residual attention (MRA) module is applied to extract rich
features. Then, with LE2, a set of enhancement weights are generated which are
utilized in feature fusion strategy and used to guide the image reconstruction.
To better preserve the local detail information and structure information, the
pixel intensity loss function based on the local region is also presented. The
experiments demonstrate that the proposed method exhibits better fusion
performance than the state-of-the-art fusion methods on public datasets
Long-term results of clear lens extraction combined with piggyback intraocular lens implantation to correct high hyperopia
<b>AIM:</b> To assess the refractive outcome of clear lensectomy combined with piggyback intraocular lens implantation in highly hyperopic patients.<b>METHODS:</b> This case review included 19 eyes of 10 patients with high hyperopia and axial length less than 21mm. Intraocular lens power was calculated for emmetropia using the Holladay II formula in 17 eyes, and SRK/T formula in 2 eyes following clear lens extraction and piggyback intraocular lens implantation. Patients were examined periodically over 24 months for visual acuity and spherical equivalent (SE).<b>RESULTS:</b> The mean postoperative SE at 24 months was 0.20±1.39D (range, -3.00 to 2.50D), better than preoperative 9.81±2.62D (range, +6.00 to +14.50D) (<i>P</i><0.001). Five eyes had SE within ±0.5D of emmetropia and 11 eyes within ±1.00D at postoperative 24 months. The mean postoperative uncorrected visual acuity (UCVA) at 24 months was 0.60±0.36, significantly improved compared to preoperative 1.39±0.33 (<i>P</i><0.001). The mean best-corrected visual acuity (BCVA) at 24 months was 0.49±0.35, not statistically different compared to preoperative 0.38±0.30 (<i>P</i>=0.34). Twelve eyes maintained and 1 gained 1 or more Snellen line of BCVA, 4 eyes lost 1 line, and 2 eyes lost 2 lines at 24 postoperative months. Twelve eyes best-corrected near visual acuity (BCNVA) achieved J1 at postoperative 24 months compared to preoperative 7 eyes and the other 7 eyes better than J3.<b>CONCLUSION:</b> Clear lens extraction combined piggyback intraocular lens implantation appears to be an effective procedure to correct high hyperopia but mild overcorrection and intralenticular opacification may require secondary procedure
Methyl 4-(4-methÂoxyÂphenÂyl)-2-methyl-5-oxo-1,4,5,6,7,8-hexaÂhydroÂquinoline-3-carboxylÂate
In the title compound, C19H21NO4, the dihydroÂpyridine ring adopts a distorted screw-boat conformation. The fused cycloÂhexenone ring forms a slightly distorted envelope conformation. The dihedral angle between the mean planes of the benzene and heterocyclic rings is 86.1 (7)°. An intraÂmolecular C—H⋯O interÂaction occurs. In the crystal, molÂecules are linked by interÂmolecular N—H⋯O hydrogen bonds, forming an infinite chain along the c axis
WavePF: A Novel Fusion Approach based on Wavelet-guided Pooling for Infrared and Visible Images
Infrared and visible image fusion aims to generate synthetic images
simultaneously containing salient features and rich texture details, which can
be used to boost downstream tasks. However, existing fusion methods are
suffering from the issues of texture loss and edge information deficiency,
which result in suboptimal fusion results. Meanwhile, the straight-forward
up-sampling operator can not well preserve the source information from
multi-scale features. To address these issues, a novel fusion network based on
the wavelet-guided pooling (wave-pooling) manner is proposed, termed as WavePF.
Specifically, a wave-pooling based encoder is designed to extract multi-scale
image and detail features of source images at the same time. In addition, the
spatial attention model is used to aggregate these salient features. After
that, the fused features will be reconstructed by the decoder, in which the
up-sampling operator is replaced by the wave-pooling reversed operation.
Different from the common max-pooling technique, image features after the
wave-pooling layer can retain abundant details information, which can benefit
the fusion process. In this case, rich texture details and multi-scale
information can be maintained during the reconstruction phase. The experimental
results demonstrate that our method exhibits superior fusion performance over
the state-of-the-arts on multiple image fusion benchmark
Drop dynamic analysis of half-axle flexible aircraft landing gear
Landing gear shock strut binding problem occurred during an unmanned aircraft’s flying test. The half-axle main landing gear of the unmanned aircraft was chosen to analyze the influences of shock strut flexibility on drop dynamics. The friction force was modeled based on the half-axle configuration and taking shock strut flexibility into account. Drop dynamic performances were analyzed and compared with those came from rigid strut model and drop test. Good correlation has been established between drop test data and the simulation predicated results. The results also showed that though the total axis force added merely 1 % when taking shock strut flexibility into account, the friction force added almost 45 %. A comprehensive deformation compatibility factor was presented to describe the actual deformation of shock strut bearings. Influence of deformation compatibility factor, flexibility of inner and outer cylinder were studied further
Inhibition of Caspase-3, -6, -8 and -9 Expression in Rats with Acute Spinal Cord Injury by Cantharidin Treatment
Purpose: To demonstrate the anti-apoptotic effects of cantharidin in mice with acute spinal cord injury (ASCI).Methods: In total, 30 male Sprague-Dawley mice were divided into three groups of 10 animals each. ASCI was induced in two of the groups using a modified Allen's method, consisting of treatment with 10 mg/kg body weight cantharidin after injury, and sacrifice on days 2, 5, 10, 20 and 30 to extract the spinal cord. The activity levels of caspase-3, -6, -8, and -9 were determined spectrophotometrically at 455 nm with a microplate reader.Results: The results showed that cantharidin treatment caused a significant reduction in the expression levels of all four caspases – caspase-3, -6, -8, and -9 – compared with the untreated groups. Two hours after ASCI, caspase levels in the cantharidin-treated group increased, reaching maximum after day 5, but were significantly lower than in the untreated group. The expression levels of caspases in the cantharidin-treated group were similar to those in the control group on days 20 and 30 following ASCI (p> 0.05).Conclusion: Cantharidin treatment exerts an anti-apoptotic effect against secondary spinal cord injury (SCI) by suppressing caspase activity. Thus, cantharidin may be suitable for the treatment of secondary SCI.Keywords: Cantharidin, Caspase, Anti-apoptotic, Inhibition, Regeneratio
Empirical study on clique-degree distribution of networks
The community structure and motif-modular-network hierarchy are of great
importance for understanding the relationship between structures and functions.
In this paper, we investigate the distribution of clique-degree, which is an
extension of degree and can be used to measure the density of cliques in
networks. The empirical studies indicate the extensive existence of power-law
clique-degree distributions in various real networks, and the power-law
exponent decreases with the increasing of clique size.Comment: 9 figures, 4 page
Heat Shock Protein 70 Protects the Heart from Ischemia/Reperfusion Injury through Inhibition of p38 MAPK Signaling.
BackgroundHeat shock protein 70 (Hsp70) has been shown to exert cardioprotection. Intracellular calcium ([Ca2+]i) overload induced by p38 mitogen-activated protein kinase (p38 MAPK) activation contributes to cardiac ischemia/reperfusion (I/R) injury. However, whether Hsp70 interacts with p38 MAPK signaling is unclear. Therefore, this study investigated the regulation of p38 MAPK by Hsp70 in I/R-induced cardiac injury.MethodsNeonatal rat cardiomyocytes were subjected to oxygen-glucose deprivation for 6 h followed by 2 h reoxygenation (OGD/R), and rats underwent left anterior artery ligation for 30 min followed by 30 min of reperfusion. The p38 MAPK inhibitor (SB203580), Hsp70 inhibitor (Quercetin), and Hsp70 short hairpin RNA (shRNA) were used prior to OGD/R or I/R. Cell viability, lactate dehydrogenase (LDH) release, serum cardiac troponin I (cTnI), [Ca2+]i levels, cell apoptosis, myocardial infarct size, mRNA level of IL-1β and IL-6, and protein expression of Hsp70, phosphorylated p38 MAPK (p-p38 MAPK), sarcoplasmic/endoplasmic reticulum Ca2+-ATPase2 (SERCA2), phosphorylated signal transducer and activator of transcription3 (p-STAT3), and cleaved caspase3 were assessed.ResultsPretreatment with a p38 MAPK inhibitor, SB203580, significantly attenuated OGD/R-induced cell injury or I/R-induced myocardial injury, as evidenced by improved cell viability and lower LDH release, resulted in lower serum cTnI and myocardial infarct size, alleviation of [Ca2+]i overload and cell apoptosis, inhibition of IL-1β and IL-6, and modulation of protein expressions of p-p38 MAPK, SERCA2, p-STAT3, and cleaved-caspase3. Knockdown of Hsp70 by shRNA exacerbated OGD/R-induced cell injury, which was effectively abolished by SB203580. Moreover, inhibition of Hsp70 by quercetin enhanced I/R-induced myocardial injury, while SB203580 pretreatment reversed the harmful effects caused by quercetin.ConclusionsInhibition of Hsp70 aggravates [Ca2+]i overload, inflammation, and apoptosis through regulating p38 MAPK signaling during cardiac I/R injury, which may help provide novel insight into cardioprotective strategies
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