Fluorescence molecular tomography system for in vivo tumor imaging in small animals

A fluorescence molecular tomography system for in vivo tumor imaging is developed using a 748-nm continuous wave diode laser as an excitation source.A high sensitivity cooled charge-coupled device (CCD) camera with excitation and emission filters is utilized to obtain the excitation and fluorescence images.The laser beam performs fast raster scanning using a dual-axis galvanometric scanner.The accuracy of the laser spot position at the source window is within ±200 μm.Based on the phantom experimental results,the spatial resolution is less than 1.7 mm,and the relative quantitation error is about 10%.In vivo imaging of a tumor-bearing nude mouse tagged with near-infrared dye demonstrates the feasibility of the system.     

Upconversion Spectrum of Tm-doped Fiber Pumped by Multiwavelengths from 760 nm to 810 nm

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Wavelet-based option pricing: An empirical study

In this paper, we scrutinize the empirical performance of a wavelet-based option pricing model which leverages the powerful computational capability of wavelets in approximating risk-neutral moment-generating functions. We focus on the forecasting and hedging performance of the model in comparison with that of popular alternative models, including the stochastic volatility model with jumps, the practitioner Black–Scholes model and the neural network based model. Using daily index options written on the German DAX 30 index from January 2009 to December 2012, our results suggest that the wavelet-based model compares favorably with all other models except the neural network based one, especially for long-term options. Hence our novel wavelet-based option pricing model provides an excellent nonparametric alternative for valuing option prices.     

亲水性FePt纳米颗粒协同催化有机污染物的降解

以半胱氨酸为配体, 采用一锅法简便合成了亲水性的FePt纳米颗粒(NPs). 超小的FePt NPs对水中常见有机污染物表现出良好的催化降解性能, 以NaBH₄为还原剂时可实现对染料罗丹明B(RhB)和有害物质4-硝基苯酚(4-NP)的有效还原; 以H₂O₂为氧化剂时可实现亚甲基蓝(MB)的高效降解. 实验结果表明, FePt NPs对3种有机污染物的降解率均高于90%. 对FePt原子对之间的协同催化机理进行了探讨, 揭示了不同反应体系中微观反应历程和催化机理的区别. 磁性测试结果表明, FePt催化剂可以通过外加磁场进行收集并重复利用, 解决了催化剂二次污染问题. 该研究为设计合成绿色环保催化剂提供了思路.     

Enantioselective epoxidation of olefins catalyzed by two novel chiral poly-salen–Mn(III) complexes

Two novel chiral poly-salen–Mn(III) complexes 1 and 2, derived from (R,R)-1,2-diaminocyclohexane and the disalicylaldehydes 5 and 6 were synthesized and employed in the enantioselective epoxidation of olefins. A range of 30–92% ee and 75–97% yield was achieved in NaClO/4-PPNO and m-CPBA/NMO oxidant systems when substituted styrenes and substituted 2,2-dimethylchromenes were used as substrates. Furthermore, the poly-salen–Mn(III) complexes could be recovered easily and recycled efficiently several times by a simple catalysis/separation method. After five reactions, an 82% ee and 78% yield of epoxide were obtained using 2,2-dimethylchromene as substrate.     

Experimental Study on Laser Behaviours of Ti：Sapphire Crystal Grown by IFUS Method

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Enhancing credit default swap valuation with meshfree methods

In this paper, we apply the meshfree radial basis function (RBF) interpolation to numerically approximate zero-coupon bond prices and survival probabilities in order to price credit default swap (CDS) contracts. We assume that the interest rate follows a Cox-Ingersoll-Ross process while the default intensity is described by the Exponential-Vasicek model. Several numerical experiments are conducted to evaluate the approximations by the RBF interpolation for one- and two-factor models. The results are compared with those estimated by the finite difference method (FDM). We find that the RBF interpolation achieves more accurate and computationally efficient results than the FDM. Our results also suggest that the correlation between factors does not have a significant impact on CDS spreads.     

k-有界sober空间的收缩与Smyth幂空间

主要讨论k-有界sober空间对遗传、收缩、函数空间和Smyth幂构造的封闭性,证明了k-有界sober空间是饱和遗传的,但不是闭遗传的;对收缩与Smyth幂构造均不具有封闭性.还证明了存在k-有界sober空间X使得函数空间[X→X]赋予点式收敛拓扑不是k-有界sober空间.     

Switching the Photoluminescence and Electrochemiluminescence of Liposoluble Porphyrin in Aqueous Phase by Molecular Regulation

By a facile peripheral decoration of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin (ATPP) with inherent aggregation-induced emission (AIE) active tetraphenylethene (TPE), a versatile AIEgenic porphyrin derivative (ATPP-TPE) was obtained, which greatly abolishes the detrimental π–π stacking and thus surmounts the notorious aggregation-caused quenching (ACQ) effect of ATPP in aqueous phase. The photoluminescence of ATPP-TPE is 4.5-fold stronger than ATPP at aggregation state. Moreover, an unequivocal aggregation induced electrochemiluminescence (AIECL) of ATPP-TPE was found to be seriously dependent on its aggregation property in aqueous solution with efficiency of 34 %, which is 6 times higher than pure ATPP. The versatility of this molecular structure modulation strategy along with the ACQ-to-AIE transformation in this work provides direction to guide for applying liposoluble porphyrins in aqueous phase by designs of synthetic porphyrin AIEgens.     

形貌可控卟啉材料的合成及光电性质

通过自组装方法制备了一种卟啉材料,并通过调节溶液pH值实现了对其形貌的可控。 当pH值较低时形成卟啉棒状结构;当pH值较高时形成卟啉叶片状结构。 利用紫外、红外和X衍射仪等多种表征方法对其结构和性质进行了表征。 结果表明,在无机酸的作用下,卟啉分子通过π-π、静电作用形成一维结构的J-聚集体;当pH值增加时,氢键的作用占主要作用形成二维片状结构。 将此卟啉棒状材料构筑微纳米器件,测试其光电性能,表明对可见光有很好的响应。 这种具有光电响应的卟啉材料有望成为微纳电子器件的光电元件。