Nickel-catalyzed three-component olefin reductive dicarbofunctionalization to access alkylborates

We report a three-component olefin reductive dicarbofunctionalization for constructing alkylborates, specifically, nickel-catalyzed reductive dialkylation and alkylarylation of vinyl boronates with a variety of alkyl bromides and aryl iodides. This reaction exhibits good coupling efficiency and excellent functional group compatibility, providing convenient access to the late-stage modification of complex natural products and drug molecules. Combined with alkylborate transformations, this reaction could also find applications in the modular and convergent synthesis of complex compounds.

Nickel-catalyzed three-component olefin reductive dicarbofunctionalization for constructing alkylborates was achieved.     

不同Tm3+浓度掺杂碲酸盐玻璃光谱性质研究

制备了70TeO2-20WO3-10ZnO-xTm2O3系统玻璃,根据所测玻璃的吸收光谱,应用Judd-Ofelt(J-O)理论计算出Tm3+离子在碲酸盐玻璃的J-O强度参数、Tm3+在玻璃中的自发辐射概率A、荧光分支比β及荧光辐射寿命τR等各项光谱参数.测定了玻璃的荧光光谱,并计算了Tm3+在碲酸盐玻璃中的荧光有效线宽、峰值受激发射截面.比较了Tm3+在不同掺杂浓度下的光谱特性,认为当Tm2O3掺杂浓度达到0.8wt%-1wt%时,所获得的荧光强度与荧光线宽达到最佳值,掺Tm3+碲酸盐玻璃是一种理想的S波段宽带光纤放大器用基质材料.     

Chimeric protein probes for C5a receptors through fusion of the anaphylatoxin C5a core region with a small-molecule antagonist

Blockade of the interaction of anaphylatoxin C5a with its receptor C5aR1 has been actively studied as a potential treatment for many inflammatory diseases; but current C5a antagonists exhibit inadequate potency and poor species cross-reactivity, and novel biochemical tools are needed to investigate whether the core region of C5a contains important interaction epitopes that can explain these limitations. Herein, we report the development of chimeric protein C5a probes containing both the complete core region of rat or human C5a, and the small-molecule antagonist PMX53-1. These probes were chemically synthesized through hydrazide-based native chemical ligation of a linear peptide hydrazide with the requisite cyclopeptidic antagonist, both of which were made by solid-phase synthesis. Quasi-racemic X-ray crystallography established that attachment of PMX53-1 did not affect the structure of the core region of C5a. Subsequent C5aR1 activity assays demonstrated the probes can provide valuable insights into the development of C5a antagonists; for example, they exhibited significantly better binding affinity and much improved species cross-reactivity than PMX53-1, supporting the notion that the effect of some epitopes outside the C-terminus of C5a should be taken into consideration when designing better C5a antagonists. Surprisingly, the core region of C5a was found to partially agonize C5aR1, suggesting the presence of more than one agonistic interaction in the binding of C5a to C5aR1. This study exemplifies the value of chemical protein synthesis in developing novel receptor probes for drug discovery research.     

Research Advances in Ambient Ionization and Miniature Mass Spectrometry

The development and applications of ambient ionization and miniature mass spectrometry are current research focus in chemical measurement. The analytical technology based on the combination of ambient ionization and miniature mass spectrometry can bypass chromatographic separation and eliminate or simplify sample pretreatment process. The protocol can reverse the labor-intensive and time-consuming drawbacks of traditional analytical methodologies, and realize rapid, on-site analysis with high sensitivity and high throughput. In this paper, the research progress and applications of ambient ionization and miniature mass spectrometry in the fields of food safety, consumer product safety, public security, life sciences and environmental monitoring, are reviewed, and future trends and prospects are discussed, which may provide technical guidance for the researchers engaged in relevant fields.     

A new method of aperture synthetizing in digital holography

This paper proposes a new method of aperture synthetizing in digital holography based on the principle of holography. In the new method aperture synthetizing is achieved by reconstructing each sub-hologram respectively, firstly, moving each reconstructed wave field referred to the benchmark reconstructed wave field according to the relationship between spacial motion and frequency shift, and finally splicing them by using superposition. Two different recording ways, using plane wave to record and using spherical wave to record, are analyzed, and their moving formula is deduced, too. Simulation and experiment are done. The results show that in comparison with the traditional method of aperture synthetizing in digital holography, the new method can decrease calculation and save reconstructed time obviously which has better applicability.     

高一学生化学基本观念现状调查研究

将化学基本观念界定为2个不同的维度,15项指标,通过自制测试卷,选取大连金普新区某一重点高中高一理科共400名学生作为调查对象,对他们的化学基本观念现状进行了调查,运用SPSS 19.0和Excel 2007对调查数据进行了处理。结果表明学生的化学基本观念总体水平不高,概念事实类基本观念处于中等偏下水平,不同化学基本观念形成不均衡,元素观、物质转化观等相对较好,而微粒观、守恒观、分类观相对较差。     

Ionization energies of beryllium in strong magnetic fields

We have develop an effective frozen core approximation to calculate energy levels and ionization enegies of the beryllium atom in magnetic field strengths up to 2.35×105T. Systematic improvement over the Hartree-Fock results for the beryllium low-lying states has been accomplished.     

Exact solution for the hydrogen atom in strong magnetic fields

The exact energy values and wavelengths of the Lyman a transition of the hydrogen atom in strong magnetic fields up to 2.35 × 105 T are obtained by using the pseudospectral method. They agree well with results calculated with the other method.     

层状CuyFe6-yAl2Ox催化剂的制备及其在罗丹明B降解反应中的应用

以铜铁铝水滑石为前驱体,经焙烧后得到了一系列不同组成的层状铜铁铝混合氧化物催化剂。将其应用于中性条件下高浓度罗丹明B(450 mg·L^-1)的类芬顿降解反应中,考察了催化剂中铜铁比例及焙烧温度对其降解性能的影响。实验结果表明,当铜铁物质的量之比为5∶1、焙烧温度为500℃时所得到的Cu5FeAl2Ox-500催化剂对罗丹明B的降解效率最高,能够在150 min内将罗丹明B完全降解。表征结果发现,Cu5FeAl2Ox-500催化剂中生成了新的CuFe2O4物相,而且具有较大的比表面积和介孔体积,因而有利于罗丹明B的降解。同时还发现该催化剂对多种污染物的降解均有很好的效果。     

近红外光谱用于杉木木材强度分等的研究

利用近红外光谱技术对木材强度分等进行了研究.选择 1000～1400 nm波段,结合偏最小二乘法,在木材强度和近红外光谱数据间建立了校正模型,校正模型的相关系数(r)为0.89,校正标准误差(SEC)为6.30 MPa.利用校正模型对35个未知样品的强度进行预测,根据近红外预测值和实测值分别对木材样品进行分等,A级预测...