Measurement of Antioxidant Capacity of Meat and Meat Products: Methods and Applications

At present, a wide variety of analytical methods is available to measure antioxidant capacity. However, this great diversity is not reflected in the analysis of meat and meat products, as there are a limited number of studies on determining this parameter in this complex food matrix. Despite this, and due to the interest in antioxidants that prevent oxidation reactions, the identification of antioxidants in meat and meat products is of special importance to the meat industry. For this reason, this review compiled the main antioxidant capacity assays employed in meat and meat products, to date, describing their foundations, and showing both their advantages and limitations. This review also looked at the different applications of antioxidant properties in meat and meat products. In this sense, the suitability of using these methodologies has been demonstrated in different investigations related to these foods.     

粘度法对可溶解的聚氨酯交联大分子的溶液行为的研究

通过体积稀释法测定可溶性交联大分子溶液的特性粘数随交联度、浓度和时间的变化,发现聚氨酯可溶性交联大分子在溶液中出现与线型和支化型高分子溶液不一样的粘度行为.本文根据聚氨酯的特殊的结构对这些异常现象进行了解释.     

电动态平衡技术在研究单颗粒煤燃烧中的应用

利用电动态平衡技术，将单个带电煤颗粒悬浮在样品池中，可以实现煤颗粒燃烧过程的原位微观研究。本文简要介绍了电动态平衡技术的原理和相关的操作方法，总结了该技术应用于煤燃烧研究的进展，进一步探讨了结合时间分辨光谱技术研究煤燃烧物理化学过程细节的可行性与发展前景。目的在于向国内研究者介绍这一新技术并激发更多的研究兴趣。     

毛细管电泳-柱端电化学检测池的设计

在射壁式检测器的基规上,设计了一种用于毛细管电泳-电化学检测装置的检测池,巧妙地利用因表面张力现象而留驻波滴曲面的放大作用,直接调整毛细管与电极之间的相对位置,无需显微镜-微调节器装置,具有空间体积小,操作更简便的优点。     

Should non-significant bias be included in the uncertainty budget?

The bias of an analytical procedure is calculated in the assessment of trueness. If this experimental bias is not significant, we assume that the procedure is unbiased and, consequently, the results obtained with this procedure are not corrected for this bias. However, when assessing trueness there is always a probability of incorrectly concluding that the experimental bias is not significant. Therefore, non-significant experimental bias should be included as a component of uncertainty. In this paper, we have studied if it is always necessary to include this term and which is the best approach to include this bias in the uncertainty budget. To answer these questions, we have used the Monte-Carlo method to simulate the assessment of trueness of biased procedures and the future results these procedures provide. The results show that non-significant experimental bias should be included as a component of uncertainty when the uncertainty of this bias represents at least a 30% of the overall uncertainty. Received: 29 May 2001 Accepted: 10 December 2001     

Microcolumn Liquid Chromatography Combined with Computer-Assisted Retention Prediction System for Polycyclic Aromatic Hydrocarbons in Extract from Diesel Particulate Matter

Abstract

Recent advances in column and instrument technology have made the development of d new generation of high-resolution microcolumn liquid chromatography possible. In addition to offering reduced solvent consumption, this chromatographic technique also yields higher mass sensitivities than those in conventional systems. In this study, the applicability of this technique to the analysis of polycyclic aromatic hydrocarbons (PAH) is investigated. PAH in the extract from diesel particulate matter were analyzed to demonstrate the utility of this approach combined with the computer-assisted retention prediction. The technique proposed in this study makes very clean and high cost-performance environmental analysis possible.     

HMBC‐ und NOESY‐NMR‐Spektroskopie

In this article we first discuss the NMR pulse sequence HMBC (heteronuclear multiple bond correlation) and demonstrate its importance for the final structure verification of the natural product cytisine. The ¹H‐, ¹³C‐, COSY‐ und HSQC‐spectra of this compound have been shown in the first two articles of this series. After this we explain the physics of the NOESY‐experiment (nuclear Overhauser effect spectroscopy) and apply this for the stereochemical assignment of the proton signals. A correlation diagram between NOE integrals and hydrogen atom distances proofs the correct analysis.     

低配位有机磷化学研究概况

长期以来,有机磷化学研究的核心内容主要集中在σ3和σ4的有机磷化合物及其衍生物方面,而低配位的有机磷化合物的研究则远远落后.本文简要综述了目前低配位的有机磷化合物σ1,λ1-亚膦烯、σ1,λ3-膦炔、σ2,λ3-膦烯和σ2,λ3-膦杂苯研究的最新进展,包括它们的合成及其在均相催化和材料等方面的应用.     

ABEEM-σπ模型在典型Diels-Alder反应立体选择性上的应用

利用ABEEM-σπ模型对Diels-Alder反应进行了理论研究,通过计算原子和π键区域的局域软度值,应用局域软度理论对典型的Diels-Alder反应的较高立体选择性给出了合理解释.     

A novel particle separation method based on induced‐charge electro‐osmotic flow and polarizability of dielectric particles

A new microfluidic method of particle separation was proposed and studied theoretically in this paper. This method is based on the induced charge electro‐osmotic flow (ICEOF) and polarizability of dielectric particles. In this method, a pair of metal plates is embedded on the side channel walls to create a region of circulating flows under applied electric field. When a dielectric particle enters this region, the vortices produced by ICEOF around the particle will interact with the circulating flows produced by the metal plates. Such hydrodynamic interaction influences the particle's trajectory, and may result in the particle being trapped in the flow circulating zone or passing through this flow circulating zone. Because the hydrodynamic interaction is sensitive to the applied electric field, and the polarizability and the size of the particles, separation of different particles can be realized by controlling these parameters. Comparing with electrophoresis and dielectrophoresis methods, this strategy presented in this paper is simple and sensitive.