On Stein’s lemma, dependent covariates and functional monotonicity in multi-dimensional modeling

Tracking the correct directions of monotonicity in multi-dimensional modeling plays an important role in interpreting functional associations. In the presence of multiple predictors, we provide empirical evidence that the observed monotone directions via parametric, nonparametric or semiparametric fit of commonly used multi-dimensional models may entirely violate the actual directions of monotonicity. This breakdown is caused primarily by the dependence structure of covariates, with negligible influence from the bias of function estimation. To examine the linkage between the dependent covariates and monotone directions, we first generalize Stein’s Lemma for random variables which are mutually independent Gaussian to two important cases: dependent Gaussian, and independent non-Gaussian. We show that in both two cases, there is an explicit one-to-one correspondence between the monotone directions of a multi-dimensional function and the signs of a deterministic surrogate vector. Moreover, we demonstrate that the second case can be extended to accommodate a class of dependent covariates. This generalization further enables us to develop a de-correlation transform for arbitrarily dependent covariates. The transformed covariates preserve modeling interpretability with little loss in modeling efficiency. The simplicity and effectiveness of the proposed method are illustrated via simulation studies and real data application.     

Effect of mesopores on solidification of sirolimus self-microemulsifying drug delivery system

The mesoporous silica materials had a high loading efficiency of sirolimus-SMEDDS. The length of the mesopores played a more important role than the pore diameter in drug dissolution and in vivo absorption.     

高锰酸钾－抗坏血酸化学发光体系测定抗坏血酸

本文研究了高锰酸钾－抗坏血酸化学发光体系，建立了测定抗坏血酸的化学发光分析新方法。线性响应的浓度范围为５．０×１０￣（－７）ｍｏｌ／Ｌ～４．０×１０￣（－５）ｍｏｌ／Ｌ检出限为３．０×１０￣（－７）ｍｏｌ／Ｌ对２．５×１０￣（－６）ｍｏｌ／Ｌ抗坏血酸进行１０次平行测定，相对标准偏差为１．６％。考察了２２种物质的干扰情况。用于维生素Ｃ片剂及注射液中抗坏血酸含量测定，结果令人满意。     

中孔分子筛在气固色谱中的应用

将中孔分子筛这一新材料应用于气固色谱，可以分离脂肪烃，芳烃，卤代烃以及一些酮类化合物。对这种中孔分子筛柱的柱效，定量解吸等情况进行了考察，并与传统的气固色谱柱和一些常用气液色谱柱进行了对比。在填补中孔材料气固色谱吸附剂空白方面作了有意义的探讨。     

Controlled aggregation of functionalized gold nanoparticles with a novel conjugated oligomer.

A new route is developed to control the self-assembly of gold nanoparticles (AuNPs) functionalized with a novel pyridyl-ended porphyrin-oligo(p-phenylene vinylene) conjugated oligomer (P-OPV-Py) into branched-rods, chain-networks, uniform fractal-like Au clusters, and larger nanoparticles. The techniques of optical spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) are used to characterize the self-assembly in various solvent systems (pure toluene, CHCl(3)/toluene, THF/toluene and n-butanol/toluene). A combination of the ligand/AuNPs molar ratio and relative concentration serves as the driving force to control the size and shape of P-OPV-Py capped AuNPs.     

油菜素甾醇激素分析的研究进展

油菜素甾醇是一类具有高生理活性的甾体激素,在植物中含量低,所在基体复杂。目前,要实现该激素的高效分离和准确定量分析仍存在很大的困难。本文综述了油菜素甾醇样品前处理方法及其分析检测技术的研究进展。共引用文献49篇。     

Tracking Cancer Metastasis In Vivo by Using an Iridium‐Based Hypoxia‐Activated Optical Oxygen Nanosensor

We have developed a nanosensor for tracking cancer metastasis by noninvasive real‐time whole‐body optical imaging. The nanosensor is prepared by the formation of co‐micelles from a poly(N‐vinylpyrrolidone)‐conjugated iridium(III) complex (Ir‐PVP) and poly(ε‐caprolactone)‐b‐poly(N‐vinylpyrrolidone) (PCL‐PVP). The near‐infrared phosphorescence emission of the nanosensor could be selectively activated in the hypoxic microenvironment induced by cancer cells. The detection ability of the nanosensor was examined in cells and different animal models. After intravenous injection, the nanosensor can be effectively delivered to the lung and lymph node, and cancer cell metastasis through bloodstream or lymphatics can be quickly detected with high signal‐to‐background ratio by whole‐body imaging and organ imaging. Moreover, the nanosensor exhibits good biocompatibility both in vitro and in vivo. The nanosensor is believed to be a powerful tool for the diagnosis of cancer metastasis.     

Fabrication of niobium doped titanate nanoflakes with enhanced visible-light-driven photocatalytic activity for efficient ibuprofen degradation

In this study, a novel class of niobium (Nb) doped titanate nanoflakes (TNFs) are fabricated through a one-step hydrothermal method. Nb doping affects the curving of titanate nanosheet, leading to the formation of nanoflake structure. In addition, Nb⁵⁺ filled in the interlayers of [TiO₆] alters the light adsorption property of pristine titanate. The band gap of Nb-TNFs is narrowed to 2.85 eV, while neat titanate nanotubes (TNTs) is 3.4 eV. The enhanced visible light adsorption significantly enhances the visible-light-driven activity of Nb-TNFs for ibuprofen (IBP) degradation. The pseudo-first order kinetics constant for Nb-TNFs is calculated to be 1.04 h^?1, while no obvious removal is observed for TNTs. Photo-generated holes (h⁺) and hydroxyl radicals (OH) are responsible for IBP degradation. The photocatalytic activity of Nb-TNFs depends on pH condition, and the optimal pH value is found to be 5. In addition, Nb-TNFs exhibited superior photo-stability during the reuse cycles. The results demonstrated Nb-TNFs are very promising in photocatalytic water purification.     

微分电位溶出法连测血清中铜铅镉锌

报道了微分电位溶出法先在０．００２５ｍｏｌ．Ｌ＾－１ＨＣｌ－０．３ｍｏｌ．Ｌ＾－１ＮＨ４Ｃｌ底液中连测血清中Ｃｕ、Ｐｂ、Ｃｄ，再加Ｃａ＾３＋０．６μｇ、０．３ｍｌＮＨ４Ｆ（２ｍｏｌ．Ｌ＾－１）于底液，稀释一倍后测Ｚｎ。Ｃｕ采用标准曲线法，Ｐｂ、Ｃｄ、Ｚｎ采用标准加入法。在选定条件下，四元素的线性关系良好。测试血汪有相对标准偏差≤４．６％，平均回收率为９３．３％－１０１．３％，结果令人满意。