Fractal analysis of two-photon microscopic images for diagnosis of nasopharyngeal cancer

In this study, two-photon microscopy (TPM) was applied to obtain high-resolution, optically sectioned images with cellular morphology information from normal and cancerous nasopharyngeal tissue. Notable difference of nuclear-cytoplasmic ratio was found between these two groups. In particular, fractal dimension (FD) analysis based on TPM images showed good differentiation between normal and cancerous nasopharyngeal tissues. Our results indicate that TPM coupled with FD analysis methods has the potential to extract diagnostic features for label-free histological diagnosis.     

Improvement and queuing analysis of the handover mechanism in the high-speed railway communication

This paper firstly analyzes the handover mechanism of vehicle-mounted base station technology in high speed railway system, and finds that the communication interruption of the physical layer will last for a period of time although the switch of MAC layer has been completed. In order to solve this problem, an improved switch mechanism is proposed in this paper in order to ensure the continuality of communication. Then the data transmission rule between RAUs and the train will be discussed through using queue theory. The original mechanism and the improved mechanism are modeled as the loss Geom/G/1 system with interruptions and vacation respectively. And the analytical equations of the loss rate and the waiting delay are deduced. Then, the numerical simulations of the two mechanisms are discussed and the relationship between the packet loss rate, the waiting delay, and the other parameters is obtained respectively. At the same time, the performance of the two mechanisms are compared by setting the same parameter values in order to verify the superiority of the proposed mechanism and its greatest advantage, that is, the improved mechanism can be compatible with all handover mechanisms.

     

REDISTRIBUTION OF HYDROGEN IN Ti ALLOY Ti-5A1-4V STRESSED INHOMOGENEOUSLY AND ITS EFFECT ON FRACTURE PROPERTIES

本文在Ti-5Al-4V合金的WOL试样裂纹尖端前13mm外的区域引入氢,结果表明,20个月后试样发生了滞后开裂。离子探针断口分析表明,在裂纹前端三向应力最大的区域,氢的聚集系数远高于Li等人的热力学理论预言值exp((V_Hσ_h)/(RT))。金相和电子显微镜研究表明,在α/β相界面及α小片间界面上生成了fct和fcc结构的氢化钛沉淀。断裂正是沿着这些界面发生的。断裂力学分析表明K_(IH)≤0.46K_(IC)。基于这些实验事实,本文讨论了钛合金中氢在非均匀应力场下再分布所能达到的程度及其动力学特征;并讨论了同类实验中一些可能导致假象的因素。     

阴极保护用三氧化二铁涂层钛阳极

本文通过电化学测试、扫描电镜与X射线衍射分析研究了Fe2O3/Ti阳极,结果表明该电极在3.5%NaCl溶液中有极化不大,耐高电流密度及消耗率低等优点,是一种很有发展前途的非贵金属阳极,适合在阴极保护和废水处理系统中应用.     

Multiphoton microscopic imaging of adipose tissue based on second-harmonic generation and two-photon excited fluorescence

The fresh adipose tissue was investigated by the use of multiphoton microscopy (MPM) based on two-photon excited fluorescence and second-harmonic generation (SHG). Microstructure of collagen and adipose cells in the adipose tissue is clearly imaged at a subcellular level with the excitation light wavelengths of 850 and 730 nm, respectively. The emission spectrum of collagen SHG signal and NADH and FAD fluorescence signal can also be obtained, which can be used to quantify the content of collagen and adipose cells and reflect the degree of pathological changes when comparing normal tissue with abnormal adipose tissue in the same condition. The results indicate that MPM has the potential to be applied to investigate the adipose tissue and can be used in the research field of lipid and connective tissues.     

Autofluorescence spectroscopy and imaging of Platymonas subcordiformis irradiated by diode laser based on LSCM

Autofluorescence spectra and optical imaging of Platymonas subcordiformis after irradiation of diode laser were observed via laser scanning confocal microscopy (LSCM). With 488 nm Ar(+) laser excitation, the horizontal and vertical dimensions of a cup-shaped chloroplast of the irradiation group increased about 10% compared with the control group. The fluorescence spectra were similar between irradiation group and control group with a maximum fluorescence band around 682 nm, whereas the former has a higher intensity. Image of a small circular substance with stronger two-photon autofluorescence (TPA) was obtained when using two-photon excitation wavelength of 800 nm in single-channel mode. Further analysis by the 800 nm excitation based on two independent-channels mode showed an emission band of the small circular substance around 376-505 nm, which corresponded to the eyespot of P. subcordiformis. In lambda scanning mode, with two-photon wavelength of 800 nm excitation, six fluorescence peaks that are located at 465, 520, 560, 617, 660 and 680 nm were observed; the fluorescence intensity of the irradiation group was higher than that of the control group, especially at 520, 560 and 617 nm. As a conclusion, diode laser irradiation can promote chloroplast growth of P. subcordiformis cells in the form of expanding area and the increasing content of protein, phospholipids and chlorophyll. LSCM, especially TPA imaging based on femtosecond laser excitation, provides a nondestructive, real-time and accurate method to study changes of living algal cells under laser irradiation and other environmental factors.     

中国古代设计艺术的文化特征

本文通过分析我国古代社会的三大历史形态(原始社会、奴隶社会和封建社会)中思想文化的特征,以及其中具有代表性的设计艺术作品表现,来探讨我国古代不同时期的设计艺术所蕴涵的独特文化特征,以达到古代设计艺术与其思想文化特征的共舞共鸣。     

榨菜腌制特征性微生物植物乳杆菌生长预测模型的研究

为了预测蔬菜低盐腌制特征性微生物在一定条件下的生长动态,将分离筛选到的植物乳杆菌L34(L.plantarum L34)作为试验菌株,建立生长预测模型。采用MRS液体培养基,调节初始pH值和NaCl浓度,在不同温度下培养,采用Origin软件进行曲线拟合及数据处理,由此建立植物乳杆菌的生长预测一级和二级模型方程。结果表明,在本试验的生长条件下,L34的生长预测一级模型可用4参数的Gompertz方程来描述,得到较高的拟合精度(Adj.R-Square在0.99以上);而由Gompertz方程得到的最大比生长速率与温度及初始pH的关系可用Ratkowsky方程来描述,最大比生长速率与NaCl浓度的关系需用多项式方程来描述;二级模型通过实验验证,得到的偏差因子在0.9~1.0之间,准确因子在1.0~1.1之间,均介于可接受范围。所建模型对利用植物乳杆菌及蔬菜低盐腌制生产的优化控制提供基础,也为更深层次模型的建立提供实验数据。     

Peptide hydrogels: Synthesis,properties, and applications in food science

Due to the unique and excellent biological, physical, and chemical properties of peptide hydrogels, their application in the biomedical field is extremely wide. The applications of peptide hydrogels are closely related to their unique responsiveness and excellent properties. However, its defects in mechanical properties, stability, and toxicity limit its application in the food field. In this review, we focus on the fabrication methods of peptide hydrogels through the physical, chemical, and biological stimulations. In addition, the functional design of peptide hydrogels by the incorporation with materials is discussed. Meanwhile, the excellent properties of peptide hydrogels such as the stimulus responsiveness, biocompatibility, antimicrobial properties, rheology, and stability are reviewed. Finally, the application of peptide hydrogel in the food field is summarized and prospected.