Correlation between Enhanced Intensity of Atherosclerotic Plaque at Contrast-enhanced Ultrasonography and Density of Histological Neovascularization

Summary： The feasibility of contrast-enhanced ultrasonography in the assessment of atherosclerotic plaque neovascularization and its relation to histological findings were investigated. Abdominal aortic atherosclerotic plaque model was induced in 25 New Zealand white rabbits by a combination of high cholesterol-rich diet and balloon aortic denudation. Standard and contrast-enhanced ultrasonography was performed at the 16th week of the model induction period. The plaques were classified as echogenic plaques or echolucent plaques according to their echogenicity at standard ultrasonography. The maxi- mum thickness of plaque was measured in the longitudinal section. Time intensity curve was used to quantify the enhanced intensity of the plaque. Animals were euthanized and abdominal aortas were har- vested for histological staining of CD31 to evaluate the neovascularization density of atherosclerotic plaque. The results showed that the echolucent plaques had higher enhanced intensity during con- trast-enhanced ultrasonography and higher neovascularization density at CD31 staining than the echo- genic plaques. The enhanced intensity of atherosclerotic plaque and its ratio to lumen were well corre- lated with histological neovascularization density （r=0.75, P〈0.001; r=0.68, P〈0.001, respectively）. However, the maximum thickness of plaque was not correlated with neovascularization density （r=0.235, P=0.081）. These findings demonstrated that the enhanced intensity in the plaque and ratio of enhanced intensity to that in the lumen of abdominal aorta may be more accurate in the evaluation of plaque neovascularization than maximum thickness. Our study indicates that contrast-enhanced ultra- sonography provides us a reliable method for the evaluation of plaque neovascularization.

Generation of non-integer high-order harmonics and significant enhancement of harmonic intensity

High-order harmonics from helium atom in the orthogonally two-color(OTC) laser field are investigated by solving the two-dimensional time-dependent Schrodinger equation.Non-integer high-order harmonics are obtained in some ratio of frequencies of two components.Pure odd and even harmonics from atoms could be separated in two components by adjusting the ratio of frequencies in OTC scheme,and the resolution of harmonics is improved at the same time.The physical mechanism is explained by the periodicity of dipole.With the same intensity of the incident laser,the intensity of the high-order harmonics from the OTC field scheme is improved by three orders of magnitude compared to the monochromatic laser field scheme.A theoretical scheme is provided for experimentally achieving improving energy resolution and separation of pure odd and even harmonics in atoms.Also,we provide a means for improving harmonic intensity.

Charge Resonance Enhanced Multiple Ionization of H2O Molecules in Intense Laser Fields

We perform a kinetically complete measurement on the fragmentation of Coulomb explosion of 1-120 molecules in intense few-cycle linearly and circularly polarized laser fields. Both the fragmentations of 1t203＋ and H204＋ reveal the concerted pathway of dissociation. The length of the OH bond prior to the Coulomb explosion of both molecular ions is sensitive to the laser pulse duration and laser intensity. However, the bending angle of H-O-H is less sensitive to the pulse duration and laser intensity. We introduce the mechanism of charge resonance enhanced double ionization to elucidate the triple （or quadruple） dissociative ionization dynamics of H20, in which two electrons are non-adiabatically localized at the protons of the precursor ion H2O^＋ （or H2O^2＋） and are released simultaneously due to the over barrier ionization in the combined laser field and molecular ionic potential. Such charge resonance enhanced multiple ionization is not suppressed in few-cycle laser fields and elliptically polarized laser fields.

Magnetic emission intensity enhancement for amorphous alloys by constructing a multi-phase structure withα-Fe nanocrystals

The perturbation in the magnetic field generated by the rotation or oscillation of magnetic domains in magnetic materials can emit low-frequency electromagnetic waves,which are expected to be used in low-frequency communications.However,the magnetic emission intensity,defined by the perturbation ability,of current commercially applied amorphous alloys,such as Metglas,cannot meet the application requirements for low-frequency antennas due to the domain motion energy loss.Herein,a multi-phase Metglas amorphous alloy was constructed by incorporatingα-Fe nanocrystals using rapid annealing to manipulate the domain movement.It was found that 3.89 times higher magnetic emission intensity is obtained compared to the pristine due to the synergism of the deformation and displacement mechanisms.Moreover,the low-frequency magnetic emission performance verification was carried out by preparing magnetoelectric composites as the antenna vibrator by assembling the alloy and macro piezoelectric fiber composites(MFC).Enhancements of magnetic emission intensity are found at 93.3%and 49.2%at the first and second harmonic frequencies compared with the unmodified alloy vibrator.Therefore,the approach leads to the development of high-performance communication with a novel standard for evaluation.

Doping inhomogeneity and staging of ultra-thin graphite intercalation compound flakes probed by visible and near-infrared Raman spectroscopy

When ultra-thin graphite intercalation compounds（GICs） are deposited on the SiO2/Si substrate, it is found that their colors are dependent on the thickness of GIC flakes. The sample colors of ultrathin GIC flakes can no longer provide qualitative information on the stage index. Here, multi-wavelength Raman spectroscopy is thus applied to study the doping inhomogeneity and staging of ultra-thin GICs by FeCl3 intercalation. The G band intensity of stage-1 GIC flakes is strongly enhanced by 532-nm laser excitation, while that of stage-2 and stage-3 flakes exhibits strong intensity enhancement for 785-nm laser excitation. The near-infrared lasers are suggested to probe the doping inhomogeneity and staging of ultra-thin GIC flakes.

Effects of Doping Trace Sm^(3+) and Gd^(3+) on Luminescent Character of Y_2O_2S∶Eu^(3+)

After trace Sm^3＋ ions and Gd^3＋ ions doping, the emission intensity of red phosphors Y2O2S： Eu^3 ＋ was enhanced and the voltage character （relation between emission intensity and excitation voltage） was improved while the other properties of physics and chemistry were not changed. The origins of enhancement and improvement are discussed. Probably the distortion and the defect of crystals are decreased by the substitution of Gd^3＋ for Y^3＋ instead of Eu^3＋ for Y^3＋ , and thus the Eu^3＋ crystal field is improved, and radiationless process and energy loss resulted from crystal defect are weakened, which leads to increased luminescence intensity and voltage character improvement. The overlapping fluorescent spectra of Y2O2S： Sm^3＋ emission and Y2O2S：Eu^3＋ excitation as well as Eu^3 ＋ excitation spectra transitions spectra lead to energy transfer from Sm^3 ＋ sensitization of Sm^3＋ ions fectively. containing Sm^3＋ excitation the possibility of resonance ions to Eu^3＋ ions, and the to Eu^3＋ ions is achieved effectively.

Time development of surface enhanced Raman intensities of the adsorbed pyrazine molecules on the silver electrode as the applied voltage varies

In this work,the time development of surface enhanced Raman intensities of the vibrational modes involving the ring skeleton and the C—H motions of the pyrazine molecule as the applied voltage on the silver electrode is shifted between -0.2 V and -0.5 V (vs.saturated calomel electrode)is reported.The observation shows that there are two processes of enhancement involved during this shift of applied voltage.One is vibrational mode dependent while the other is not.The detailed behavior of these two processes of enhancement is discussed along with the retarded response of the Helmholtz double layer structure to the change of the applied voltage on the electrode.

通过Ag阵列耦合增强少层InSe的光学响应

具有高发光性能的二维材料被认为是实现光电器件应用的极具前途的材料.其中,硒化铟(InSe)是一种具有代表性的二维材料,近些年在光电领域表现出巨大的应用潜力,因此吸引了研究者们的广泛关注.然而,InSe的光-物质相互作用极其微弱,因为其带隙激子的偏振取向是面外的,主要被面外偏振光激发而对正常入射光(面内偏振)的响应极其微弱,这大大限制了其在光电器件中的实际应用.在此,我们提出了一种方法,即通过将少层InSe转移到Ag纳米棱镜阵列上,显著提升InSe在线性和非线性体系的光学响应.结合实验分析,增强的机理主要来自于两种机制的协同作用:一方面,局域表面等离子体共振产生的局部强化电磁场垂直分布于金属表面,与面外偏振的InSe带隙激子发生高效耦合,增强了InSe的光-物质相互作用;另一方面,独特设计的弯曲结构增加了入射光在平面外的偏振分量,促使InSe面外激子对光的吸收和散射效率增强.通过进一步调整InSe的厚度,我们实现了光致发光和二次谐波信号的两个数量级的增强.因此,我们的工作为改善InSe的光学特性提供了一个有效的途径,使其在光电器件的实际应用中迈出了重要的一步.