Eco friendly synthesis of fluorescent carbon dots for the sensitive detection of ferric ions and cell imaging

This study established a ferric ion (Fe³⁺) detection method as a result of the fluorescence quenching effect of Fe³⁺ on carbon dots (CDs). Specifically, we proposed, a green microwave synthesis route towards fluorescent CDs that requires only the brewer’s spent grain as starting materials. Transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectra and X-ray photoelectron spectroscopy were performed to investigate the CDs characteristic: morphology, size distribution, functional groups, and composition, respectively. The experimental results, which were run under optimal experimental conditions, indicated that the fluorescence intensity and concentration of Fe³⁺ were within the desired linear range (0.3–7 μM). The detection limit of this assay towards Fe³⁺ was 95 nM. The proposed method showed significant selectivity with respect to interfering ions. We evaluated the potential application of this method with tap water, lake water and fetal bovine serum as real samples. Additionally, the CDs could be served as superior bioimaging probes in Hela cells as a result of their excellent optical stability and good biocompatibility. In a word, the present study provides a new idea for CDs derived from the waste of agricultural products for detecting food or environmental contaminants and cell imaging.     

杉木针叶磷脂酰甘油脂肪酸组成分析

用改进的DEAE阴离子交换柱色谱法和硅胶薄层色谱法分离制备杉木针叶磷脂酸甘油，用气相色谱法测定了它的脂肪酸组成。分析结果表明，抗寒性强的杉木品种的针叶磷脂酰甘油脂肪酸的（18:1＋18:2＋18:3）／[16:0＋16:1（3t）]比值比不抗寒品种的高。     

高纯度植酸的制备

高纯度植酸的制备孙定光胡佩廖显威（四川师范大学化学系成都６１００６６）关键词植酸制备高纯试剂中图分类号Ｏ６２９．９植酸（ＰｈｙｔｉｃＡｃｉｄ）又名肌醇六磷酸酯，分子式：Ｃ６Ｈ１８Ｏ２４Ｐ６，结构为植酸是中等强度的有机酸，因其结构特殊，具极强的螯合作用...     

714名0—6岁儿童头发中微量元素水平的研究

报道了深圳市南山区７１４名０￣６岁儿童头发中６种必需微量和宏量元素的水平，分析了不同年龄、性别儿童６种元素的异常状况，研究结果表明，儿童头发中锌、铜、铁、钙和锰元素缺乏状况相当严重总缺乏率占８９．９％。     

Hazard regression with penalized spline: The smoothing parameter choice and asymptotics

In this article, we use penalized spline to estimate the hazard function from a set of censored failure time data. A new approach to estimate the amount of smoothing is provided. Under regularity conditions we establish the consistency and the asymptotic normality of the penalized likelihood estimators. Numerical studies and an example are conducted to evaluate the performances of the new procedure.     

Extensions of the Borel–Cantelli lemma in general measure spaces

In this paper, an important bilateral inequality for a sequence of nonnegative measurable functions on a measure space \((S,\mathcal {B}_S,\mu )\) is obtained, and some sufficient conditions for \(\mu \left( \limsup \limits _{n\rightarrow \infty }A_n\right) =\mu (S)\) are given. In addition, a weighted version of the Borel–Cantelli Lemma on the measure space is obtained. Our results generalize the corresponding ones for bounded random sequences to the case of unbounded measurable functions.     

Quasi-maximum likelihood estimators in generalized linear models with autoregressive processes

The paper studies a generalized linear model(GLM)y_t = h(x_t~T β) + ε_t,t = l,2,...,n,where ε_1 = η_1,ε_1 =ρε_t +η_t,t = 2,3,...;n,h is a continuous differentiable function,η_t's are independent and identically distributed random errors with zero mean and finite variance σ~2.Firstly,the quasi-maximum likelihood(QML) estimators of β,p and σ~2 are given.Secondly,under mild conditions,the asymptotic properties(including the existence,weak consistency and asymptotic distribution) of the QML estimators are investigated.Lastly,the validity of method is illuminated by a simulation example.     

Generalized area operators on L^p（R^n）

We introduce the generalized area operators by using nonnegative measures defined on upper half-spaces R＋^n＋1. The characterization of the boundedness and compactness of the generalized area operator from LP（]Rn） to Lq（IRn） is investigated in terms of s-Carleson measures with 1 〈 p, q 〈 ＋∞. In the case of p = q = 1, the weak type estimate is also obtained.     

组合计数的群论与计算机方法

本文综述组合数学和图论中解决计数问题的群论与计算机方法及其最新发展。传统的计数方法得到有限的计数公式或递推公式等，然而许多复杂的问题很难得到有限的表达式，即使能得到，公式也往往非常复杂。由于计算机技术的发展不仅使复杂的计数公式有了实际意义，而且可以设计恰当的计算方法进行数值计算，使计数问题有更为广阔的发展领域。另一方面，为了计算不同构的图或组合结构，最有效的方法是群论方法，因此把群论方法与计算机方     

关于矩阵二次型极值的若干结果

本文出于统计研究的需要，系统地讨论了Ｒａｙｌｅｉｇｈ－Ｒｉｔｚ定理在矩阵形式下的推广，给出了若干新结果，完善了现有文献中这方面的研究。