Pointwise bounds for L 2 eigenfunctions on locally symmetric spaces

We prove pointwise bounds for L ² eigenfunctions of the Laplace-Beltrami operator on locally symmetric spaces with -rank one if the corresponding eigenvalues lie below the continuous part of the L ² spectrum. Furthermore, we use these bounds in order to obtain some results concerning the L ^p spectrum.     

The direct decomposition of NO over the La2CuO4 nanofiber catalyst

The NO catalytic direct decomposition was studied over La₂CuO₄ nanofibers, which were synthesized by using single walled carbon nanotubes (CNTs) as templates under hydrothermal condition. The composition and BET specific surface area of the La₂CuO₄ nanofiber were La₂Cu_0.88²⁺Cu_0.12⁺O_3.94 and 105.0 m²/g, respectively. 100% NO conversion (turnover frequency-(TOF): 0.17 g_NO/g_catalyst s) was obtained over such nanofiber catalyst at temperatures above 300 °C with the products being only N₂ and O₂. In 60 h on stream testing, either at 300 °C or at 800 °C, the nanofiber catalyst still showed high NO conversion efficiency (at 300 °C, 98%, TOF: 0.17 g_NO/g_catalyst s; at 800 °C, 96%, TOF: 0.16 g_NO/g_catalyst s). The O₂ and NO temperature programmed desorption (TPD) results indicated that the desorption of oxygen over the nanofibers occurred at 80-190 and 720-900 °C; while NO desorption happened at temperatures of 210-330 °C. NO and O₂ did not competitively adsorb on the nanofiber catalyst. For outstanding the advantage of the nanostate catalyst, the usual La₂CuO₄ bulk powder was also prepared and studied for comparison.     

Approximately solving multiobjective linear programmes in objective space and an application in radiotherapy treatment planning

In this paper, we propose a modification of Benson’s algorithm for solving multiobjective linear programmes in objective space in order to approximate the true nondominated set. We first summarize Benson’s original algorithm and propose some small changes to improve computational performance. We then introduce our approximation version of the algorithm, which computes an inner and an outer approximation of the nondominated set. We prove that the inner approximation provides a set of -nondominated points. This work is motivated by an application, the beam intensity optimization problem of radiotherapy treatment planning. This problem can be formulated as a multiobjective linear programme with three objectives. The constraint matrix of the problem relies on the calculation of dose deposited in tissue. Since this calculation is always imprecise solving the MOLP exactly is not necessary in practice. With our algorithm we solve the problem approximately within a specified accuracy in objective space. We present results on four clinical cancer cases that clearly illustrate the advantages of our method.     

Structure analysis of triterpene saponins in Polygala tenuifolia by electrospray ionization ion trap multiple-stage mass spectrometry

Eighteen different triterpene saponins isolated from Polygala tenuifolia were investigated by electrospray ionization ion trap multiple-stage mass spectrometry (ESI-ITMS(n)) in positive and negative ion modes. MS(1)-MS(3)/MS(4) spectra of the both modes were analyzed, and they all gave fragments in line and shared common fragmentation patterns. Key fragments from MS(n) spectra of both the modes and their proposed fragmentation pathways were constructed with examples illustrated for the formation of characteristic fragments in the saponins. Two special fragmentation patterns were proposed: (1) the formation of fragments by cleavage of CH(2)O from Delta(12)-14alpha-CH(2)OH of the oleanene-type saponin aglycone in both positive and negative MS(n) (n > or = 2) modes; (2) the occurrence of fragments by cleavage of CO(2) and 3-glucose as the characteristic structure feature of 23-COOH at the oleanene-type saponin aglycones coupled with 3-Glc substitutes in the negative MS(n) (n > or = 2) modes. Peak intensities in MS(n) spectra were also correlated with structural features and fragmentation preferences of the investigated saponins, which are discussed in detail. In general, fragments formed predominantly by cleavages of glycosidic bonds in the positive mode, while selective cleavages of acyl bonds preceded that of glycosidic bonds in negative MS(n) (n > or = 2) mode, both of which could well be applied to the structural analysis of these saponins. Interpretation of MS(n) spectra presented here provided diagnostic key fragment ions important for the structural elucidation of saponins in P.tenuifolia.     

二(2-乙基己基)膦酸从盐酸介质中萃取钪(Ⅲ)、钇(Ⅲ)、镧系离子(Ⅲ)和铁(Ⅲ)

本文研究了二(2-乙基己基)膦酸(H[DEHP])的正辛烷溶液从盐酸介质中萃取钪(Ⅲ)、钇(Ⅲ)、镧系离子(Ⅲ)和铁(Ⅲ)的平衡规律。结果表明,H[DEHP]对上述离子的萃取次序是Sc³⁺>Fe³⁺>Lu³⁺>Yb³⁺>Er³⁺>Y³⁺>Ho³⁺。讨论了Sc(Ⅲ)与Fe(Ⅲ)、Y(Ⅲ)、Ln(Ⅲ)(镧系离子)以及Fe(Ⅲ)与重镧系离子(Ⅲ)分离的可能性,并与HEH[EHP]萃取上述离子的性能进行了比较。借助IR、NMR和斜率法,饱和法研究了低酸度下H[DEHP]萃取Sc(Ⅲ)、Y(Ⅲ)和Ln(Ⅲ)的平衡反应,计算了浓度平衡常数和萃取反应的热力学函数。     

涂碳CdBr42-离子选择电极的研制

R.W.Cattrall等曾研制PVC膜CdCl₄^2-离子选择电极,其线性响应范围10^-1-10^-4M,级差26-28mV。本文报道以三辛基十二烷基碘化铵与镉澳络阴离子形成的缔合物为电活性物的涂碳(PVC膜)CdBr₄^2-离子选择电极的研究结果。     

Facile preparation of nano-g-C3N4/UiO-66-NH2 composite as sorbent for high-efficient extraction and preconcentration of food colorants prior to HPLC analysis

In this work,the nano-g-C₃N₄/Ui O-66-NH₂composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C₃N₄/Ui O-66-NH₂composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatogra...     

Region-Specific Biomarkers and Their Mechanisms in the Treatment of Lung Adenocarcinoma: A Study of Panax quinquefolius from Wendeng,China

Panax quinquefolius, a popular medicinal herb, has been cultivated in China for many years. In this work, the region-specific profiles of metabolites in P. quinquefolius from Wendeng was investigated using liquid-chromatography–quadrupole–time-of-flight-(LC–Q–TOF)-based metabolomics analysis. The three most abundant biomarkers, identified as ginsenoside Rb₃, notoginsenoside R₁, and ginsenoside Rc, were the representative chemical components employed in the network pharmacology analysis. In addition, molecular docking and western blotting analyses revealed that the three compounds were effective binding ligands with Hsp90α, resulting in the inactivation of SRC and PI3K kinase, which eventually led to the inactivation of the Akt and ERK pathways and lung cancer suppression. The outcomes obtained herein demonstrated the intriguing chemical characteristics and potential functional activities of P. quinquefolius from Wendeng.     

用于正电子断层扫描成像的68Ga标记PM2.5模拟粒子的制备及其活体示踪

将黑色素纳米颗粒(melanin nanoparticle,MNP)经聚乙二醇(polyethylene glycol,PEG)修饰制备得到PEG-MNP,随后通过与放射性的⁶⁸Ga³⁺离子螯合,高标记产率地制备得到⁶⁸Ga-PEG-MNP,标记产物稳定性良好。进一步将⁶⁸Ga-PEG-MNP通过雾化方式制备得到⁶⁸Ga-PEG-MNP PM_2.5(particulate matter 2.5,size<2.5μm)模拟颗粒,其经雾化小鼠吸入体内后,通过正电子断层扫描(positron emission tomography,PET)成像对小鼠进行全身显影,结果可见雾化的⁶⁸Ga-PEG-MNP PM_2.5模拟颗粒可由气管向肺部双叶区域扩散,并滞留于肺。体内的PET成像结果与离体放射自显影结果高度一致。     

石墨烯基催化剂的设计合成与电催化应用

为了解决能源匮乏和环境污染的问题,研究人员正致力于寻找清洁可持续的新能源。 其中,氧气还原、氧气析出、析氢反应等是紧密联系新型清洁能源获取和存贮的重要电化学反应。 为了提高其能量转化效率,电催化剂(如碳载铂Pt/C)被广泛地用于降低其反应活化能、提高能量转化效率。 近年来,石墨烯作为一种具有高比表面积和优异导电性的二维碳材料受到了广泛关注。 通过表面杂原子掺杂、缺陷调控和引入催化活性组分等方式,获得了催化性能与贵金属催化剂相媲美,且低价格和高稳定性的非贵金属石墨烯基催化材料。 针对氧气还原、氧气析出和析氢反应在燃料电池、金属-空气电池和电催化水分解中的应用,本文概括综述了通过表/界面结构性质调控提高石墨烯电催化性能和稳定性,获得具有双功能或复合催化性能的石墨烯基催化剂的最新研究进展。 最后总结和展望了亟待解决的问题及未来的发展趋势。