石英Al2O3 PLOT柱在油气化探中的应用

报导了采用石英Ａｌ２Ｏ３ＰＬＯＴ柱分析油气化探样品的组成，在同一色谱条件下，该柱既能用于野外采样后现场直接分析游离烃，又能在室内分析酸解烃。具有分析周期短，重复性好，柱寿命长等优点，为石油勘探取样迅速准确的分析发挥了重要作用。     

Crosslinked Aspartic Acids as Helix‐Nucleating Templates

Described is a facile helix‐nucleating template based on a tethered aspartic acid at the N‐terminus [terminal aspartic acid (TD)]. The nucleating effect of the template is subtly influenced by the substituent at the end of the side‐chain‐end tether as indicated by circular dichroism, nuclear magnetic resonance, and molecular dynamics simulations. Unlike most nucleating strategies, the N‐terminal amine is preserved, thus enabling further modification. Peptidomimetic estrogen receptor modulators (PERMs) constructed using this strategy show improved therapeutic properties. The current strategy can be regarded as a good complement to existing helix‐stabilizing methods.     

Pd-Enriched-Core/Pt-Enriched-Shell High-Entropy Alloy with Face-Centred Cubic Structure for C1 and C2 Alcohol Oxidation

High-entropy alloy nanoparticles (HEA NPs) have aroused great interest globally with their unique electrochemical, catalytic, and mechanical properties, as well as diverse activity and multielement tunability for multi-step reactions. Herein, a facile low-temperature synthesis method at atmospheric pressure is employed to synthesize Pd-enriched-HEA-core and Pt-enriched-HEA-shell NPs with a single phase of face-centred cubic structure. Interestingly, the lattice of both Pd-enriched-HEA-core and Pt-enriched-HEA-shell enlarge during the formation process of HEA, with tensile strains included in the core and shell of HEA. The as-obtained PdAgSn/PtBi HEA NPs show excellent electrocatalytic activity and durability for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The specific (mass) activity of PdAgSn/PtBi HEA NPs for MOR is 4.7 mA cm⁻² (2874 mA mg_(Pd+Pt)⁻¹), about 1.7 (5.9) and 1.5 (4.8) times higher than that of commercial Pd/C and Pt/C catalysts, respectively. Additional to high-entropy effect, Pt sites and Pd sites on the interface of the HEA act synergistically to facilitate the multi-step process towards EOR. This study offers a promising way to find a feasible route for scalable HEA manufacturing with promising applications.     

Chitosan modified poly(L-lactide) microspheres as cell microcarriers for cartilage tissue engineering

The surfaces of poly(l-lactide) (PLLA) microspheres were modified by chitosan via a method of hydrolysis and grafting-coating to improve their compatibility to chondrocytes. The PLLA microspheres with a diameter of 74-150mum were fabricated by an oil/water emulsion solvent evaporation method, followed by hydrolysis in alkaline solution to produce a larger number of carboxyl groups. Using water-soluble carbodiimide as a coupling reagent, chitosan was covalently grafted onto the microspheres. Due to the physical entanglement and insolubility at neutral pH, unbonded chitosan molecules were stably remained to yield a large amount of coated chitosan. Biological performance of the control PLLA and the chitosan-coated PLLA microspheres were assessed by in vitro culture of rabbit auricular chondrocytes. After 24h and 7d culture, the chitosan-coated PLLA microspheres, especially the ones with larger chitosan amount, exhibited stronger ability to promote cell attachment and proliferation, and maintain the secretion function of the chondrocytes. Therefore, the chitosan-coated PLLA microspheres can be potentially used as the injectable cell microcarriers for chondrogenesis in cartilage tissue engineering.     

A Deficiency-One Algorithm for power-law kinetic systems with reactant-determined interactions

This paper addresses the problem of determining the capacity of a deficiency-one network, endowed with rate laws more general than mass action kinetics, to admit multiple positive steady states—that is, whether there exist rate constants such that the corresponding differential equations admit two distinct stoichiometrically compatible steady states where all concentrations are positive. We extend the Deficiency-One Algorithm of M. Feinberg to deal with PL-RDK systems, which are kinetic systems with power-law rate functions whose kinetic orders are identical for reactions with the same reactant complex. The algorithm is applied to a power-law approximation of the Earth’s pre-industrial carbon cycle model, which gave the original motivation for our study.     

Alloxan诱发糖尿病实验大鼠微量元素谱的多元分析

为确认Ａｌｌｏｘａｎ发糖尿病鼠与微量元素的关连，用多元分析研究了糖尿病鼠样品中微量元素，并引出对糖尿病的新见解。用ＩＣＰ－ＡＥＳ测定了Ａｌｌｏｘｚｎ诱发糖尿病鼠和对照鼠的骨、心、肾、脾、肺、肝、血和毛中１９种微量和宏量元素（Ａｌ、Ａｓ、Ｂ、Ｂａ、Ｃｄ、Ｃｏ、Ｃｒ、Ｍｇ、Ｍｎ、Ｎｉ、Ｐｂ、Ｓｅ、Ｚｎ、Ｆｅ、Ｃｕ、Ｓｒ、Ｔｉ、Ｖ） ，结果在糖尿病鼠与对照经组的微量元素间呈现一些显著差异。多元分析找到     

An Ultra‐High Fluorescence Enhancement and High Throughput Assay for Revealing Expression and Internalization of Chemokine Receptor CXCR4

Revealing chemokine receptor CXCR4 expression, distribution, and internalization levels in different cancers helps to evaluate cancer progression or prognosis and to set personalized treatment strategy. We here describe a sensitive and high‐throughput immunoassay for determining CXCR4 expression and distribution in cancer cells. The assay is accessible to a wide range of users in an ordinary lab only by dip‐coating poly(styrene‐co‐N‐isopropylacrylamide) spheres on the glass substrate. The self‐ assembled spheres form three‐dimensional photonic colloidal crystals which enhance the fluorescence of CF647 and Alexa Fluor 647 by a factor of up to 1000. CXCR4 in cells is detected by using the sandwich immunoassay, where the primary antibody recognizes CXCR4 and the secondary antibody is labeled with CF647. With the newly established assay, we quantified the total expression of CXCR4, its distribution on the cell membrane and cytoplasm, and revealed their internalization level upon SDF‐1α activation in various cancer cells, even for those with extremely low expression level.     

The effect of hydrogen bond donors in asymmetric organocatalytic conjugate additions

A series of primary amine organocatalysts with various hydrogen bond donors were prepared and examined in the conjugate addition of isobutyraldehyde and acetone to trans-β-nitrostyrene and (E)-methyl 2-oxo-4-phenylbut-3-enoate. The effect of N–H acidity and hydrogen-bonding modes of the catalysts on the catalytic activity and enantioselectivity was studied. The experimental results did not support a general correlation of N–H acidity and hydrogen-bonding modes with catalytic activity and enantioselectivity. The catalysts with double hydrogen-bonding interactions provided better catalytic activities and enantioselectivities than the catalysts with single hydrogen-bonding interactions for the reaction of trans-β-nitrostyrene. The catalyst with the most acidic N–H bond showed the best catalytic activity and enantioselectivity for the reaction of (E)-methyl 2-oxo-4-phenylbut-3-enoate. These results suggest that the effect of hydrogen bond donors in organocatalytic reactions may be highly dependent on the substrates and the reaction conditions.