Sonodynamically induced anti-tumor effect with protoporphyrin IX on hepatoma-22 solid tumor

Objective

The purpose of this study was to evaluate sonodynamically induced anti-tumor effect of protoporphyrin IX (PPIX) in mice bearing hepatoma-22 (H-22) solid tumors, and the possible in vivo cell damage mechanism was also investigated.

Methods

The pharmacokinetics of PPIX was analyzed in plasma, skin, muscle and tumor of H-22 bearing mice. Tumors were irradiated with ultrasound (1.43 MHz, I_SATA 3 W/cm², 3 min) for three times at 8, 12 and 24 h after 5.0 mg/kg PPIX administration, respectively. The anti-tumor effects of sonodynamic therapy (SDT) were estimated by the tumor inhibition ratio (volume and weight). The bio-effects of SDT were evaluated by hematoxylin and eosin (H&E) staining, transmission electron microscope (TEM) observation, lipid peroxidation (LPO) measurement and anti-oxidative enzymes (glutathione peroxidase (GSH-PX), catalase (CAT) and superoxide dismutase (SOD)) assay.

Results

A significant anti-tumor effect was obtained by PPIX-mediated sonodynamic therapy (PPIX-SDT). At the fifteenth day after PPIX-SDT, the tumor growth and tumor weight inhibition ratios were 53.84% and 45.86%, respectively. In addition, the structure of tumor tissues and the anti-oxidative enzymes were obviously destroyed after SDT treatment.

Conclusions

A biochemical mechanism was involved in PPIX-SDT in vivo, and the free radicals produced by the synergistic treatment destroying the anti-oxidative system of tumor cells in vivo may play an important role in this action. Also, the thermal effect could not be excluded in inducing damage of cellular structures, like membrane disruption and chromatin condensation under current evaluation in this paper.     

High spatial resolution distributed strain sensor based on linear chirped fiber Bragg grating and fiber loop ringdown spectroscopy

A simple sensor system for high spatial resolution distributed strain field measurement is proposed and demonstrated experimentally. The fiber loop ringdown technique combined with a linear chirped fiber Bragg grating is used to realize the high spatial resolution. A proof-of-concept distributed strain sensor with 2?mm spatial resolution is realized. The sensor network is also explored and researched experimentally. The proposed technique suggests a broad range of applications for real-time distributed physical parameter sensing, such as strain or temperature.     

Scattering-induced changes in the temporal coherence length and the pulse duration of a partially coherent plane-wave pulse

The scattering of a partially coherent plane-wave pulse on a Gaussian-correlated, quasi-homogeneous random medium is investigated. The analytical expressions for the temporal coherence length and the pulse duration of the scattered field are derived. We demonstrate that the scattering-induced changes in the temporal coherence length and the pulse duration may be used to determine the correlation function of the scattering potential of the medium.     

Influence of pores on the surface microcompression mechanical response of thermal barrier coatings fabricated by atmospheric plasma spray—Finite element simulation

Surface microcompression is a very important technique to characterize the mechanical properties of film and coating systems. In this paper, surface microcompression simulation for La₂Zr₂O₇ (LZ) thermal barrier coatings (TBCs) was implemented by finite element method, especially, the influence of pores on the surface microcompression mechanical response of the thermal barrier coatings fabricated by atmospheric plasma spray (APS) was focused on. The simulation results indicate that the pores not only affect the stress distribution beneath the contact area between the indenter and coating surface, but also affect the shape of the force-displacement curve and the plastic deformation behavior of TBCs. The micromechanism was discussed in detail in this study. At the same time, by using the surface microcompression technique, a new direction or method was proposed to characterize the pore content of the coating quantitatively.     

Evolution of Zn based high purity phases under NH3 gas atmosphere and their PL properties

We report here the evolution of zinc based high purity phases with novel morphologies such as Zn₃N₂ hollow structures, ZnO nanowires and nanopowders, as well as metallic Zn layered hexagonal microparticles at progressively increased reaction temperature of 600 °C, 700 °C, 800 °C under NH₃ gas atmosphere using Zn powder precursor and keeping all other experimental parameters unchanged. Growth mechanism for Zn₃N₂ obtained by nitridation, ZnO by oxidation and Zn microparticles via thermal evaporation & condensation process are discussed briefly. The as-synthesized products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). Photoluminescence (PL) studies have revealed very interesting and infrequently observed emission bands at 378 and 661 nm for Zn₃N₂, 359 and 396 nm for ZnO as well as 389 nm for Zn polyhedral microparticles.     

Piezoelectric coefficients of cross-linked polypropylene films stretched at elevated temperatures

Cross-linked polypropylene (XPP) foams are modified by a hot-stretching process and charged to be piezoelectric. The results show that a piezoelectric d₃₃ -coefficient of 308pC/N is obtained for sample with an elongation ratio of 200%. The dynamic d₃₃ value is smaller than the quasi-static value, which is probably due to the rise of Young’s modulus with increasing frequency. All the samples show pressure-independent d₃₃ in the range up to 30 kPa. Improved d₃₃ was obtained in the sample rough surface exposed to the corona during charging. Compared to linear PP, the stretched XPP shows pressure independence of d₃₃ in larger range.     

Ballistic phonon transport through a Fibonacci array of acoustic nanocavities in a narrow constriction

We investigate the ballistic phonon transport through a Fibonacci array of acoustic nanocavities in a narrow constriction of a semiconductor nanowire at low temperatures. It is found that the transmission spectrum of such a system consists of quasiband gaps and narrow resonances caused by the coupling of phonon waves. Both phonon transmission and thermal conductance exhibit the similarity due to the Fibonacci sequence structure. The similarity is sensitive to the number n and parameters of nanocavities. The results are compared with those in a periodic acoustic nanocavities.     

傅里叶变换中红外光谱法检测脑膜瘤的研究

采用傅里叶变换衰减全反射中红外光谱法检测了24例液氮冻存的脑膜瘤离体样品(其中良性肿瘤12例,有恶性倾向的肿瘤12例),对得到的红外光谱进行整理分析,发现不同类型脑膜瘤组织(如纤维型脑膜瘤和内皮型脑膜瘤)的红外光谱存在着差异,并且同一种类型的脑膜瘤组织,其恶性倾向的程度不同,他们的红外光谱也表现出较为明显的区别,因此,我们可以从各个特征吸收峰的峰位、峰形及峰强等信息的变化来区分脑膜瘤,并可以初步鉴别脑膜瘤的性质;研究结果发现,通过某些特征吸收峰(如1 160cm-1)峰位的变化来鉴别脑膜瘤的性质与病理诊断结果的符合率大于85%,说明傅里叶变换衰减全反射中红外光谱法有可能发展成为一种对样品无损伤、快速的脑肿瘤诊断新方法。     

对流占优的Sobolev方程的投影稳定化有限元方法

对于对流占优的Sobolev方程,提出了一种新的投影稳定化有限元方法,建立了半离散和全离散的投影稳定化格式,给出了解的稳定性和收敛性分析.该方法能够有效克服对流占优,与内罚方法相比,投影格式更简单,计算量更小,且得到的C—N格式是无条件稳定的,时间精度达到了二阶.最后,通过实验证明,数值结果与理论结果完全一致.