Evaluation of important fatty acid ratios in poultry feed lipids by ATR FTIR spectroscopy

A rapid, simple and reproducible single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopic method was developed for determination of the n − 6, n − 3 and ratio of n − 6:n − 3 polyunsaturated fatty acids (PUFAs) in poultry feed lipids using partial least squares (PLS) regression. Data for n − 6, n − 3 and ratio of n − 6:n − 3 was acquired by gas chromatography (GC) and used as a standard values for FTIR calibration. The best regression results were achieved using first derivatives of the 1475–650 cm⁻¹ spectral region for n − 6, n − 3 and ratio of n − 6:n − 3 with high regression coefficients (R²) of 0.999, 0.994 and 0.998, respectively and low RMSEP values of 1, 0.06 and 0.83, respectively. The results of the present study revealed that FTIR could be used for rapid and accurate determination of n − 6, n − 3 and ratio of n − 6:n − 3 PUFAs present in poultry feed lipids.     

利用回归分析研究火焰离子化检测器相对响应值

以乙酸乙酯对正庚烷的相对摩尔响应值（Ｓ＿Ｍ）为例，研究了Ｎ＿２，Ｈ＿２流速对Ｓ＿Ｍ的影响，得到了回归方程并求得了最佳操作条件。     

A novel quartz crystal microbalance gas sensor based on porous film coatings. A high sensitivity porous poly(methylmethacrylate) water vapor sensor

We describe a novel and generally applicable approach for creating voids in films deposited on the surface of solid substrates. Such films are advantageous when a quartz crystal microbalance (QCM) is the basis of a sensor. We show that films with large void volumes produce more sensitive sensors than with the original film. Poly(methylmethacrylate) (PMMA) was used as the polymer layer deposited on a quartz crystal microbalance (QCM) to demonstrate our technique for the model system of water vapor analysis in flowing nitrogen gas. A film of pure PMMA on a QCM is a sensor for water vapor in a gas phase. A more sensitive sensor was created by dip coating QCM crystals into solutions containing mixtures of PMMA and poly(d,l-lactide) (PDLL) and then evaporating the solution films on the QCM crystals to form mixed polymer films of varying PDLL content. The PDLL was then removed from the mixed polymer films by exposure to a NaOH solution to form pure PMMA films having various void volumes. A leached PMMA film that originally contained 50% by weight PDLL had a 3.7 times larger QCM sensitivity for water vapor than a pure PMMA film.     

Affinity-based microdialysis sampling using heparin for in vitro collection of human cytokines

Microdialysis sampling is a widely used method to sample from complex biological matrices. Cytokines are important signaling proteins that are typically recovered with low relative recovery values during microdialysis sampling. Heparin was included in the microdialysis perfusion fluid as an affinity agent to increase in vitro recovery of different cytokines through polyethersulfone (PES) microdialysis membranes with 100 kDa molecular weight cutoff. No change in fluid volumes collected from the microdialysis probes occurred when heparin was included in the perfusion fluid up to concentrations of 10 μM. The loss of heparin (10 μM) across the dialysis membrane was minimal (2.7 ± 0.9%, n = 3). Additionally, heparin at these concentrations did not interfere with the cytokine immunoassays. The control and heparin-enhanced relative recoveries for five human cytokines using 0.1 μM heparin in the microdialysis perfusion fluid flowing at 0.5 μL min⁻¹ were (n = 3): interleukin-4 (IL-4), 4.2 ± 0.5% and 7.2 ± 3.1%; interleukin-6 (IL-6), 1.4 ± 0.8% and 3.6 ± 1.3%; interleukin-7 (IL-7), 1.3 ± 0.8% and 4.8 ± 1.8%; monocyte chemoattractant protein-1 (MCP-1), 9.0 ± 1.6% and 19.5 ± 2.7%; and tumor necrosis factor-α (TNF-α), 7.4 ± 1.3% and 16.9 ± 1.6%, respectively. Heparin increased the microdialysis sampling relative recovery of several human cytokines in vitro.     

试验箱温、湿度校准装置的研制

介绍试验箱温、湿度校准装置的模型建立,温、湿度传感器的选择及软硬件构成,利用温、湿度精密测量,多路信号输入,单片机控制等功能,实现装置的温、湿度多点校准。通过验证试验证明该装置测量准确可靠。     

Summary of ISO/TC 201 Standard: XX ISO 18118: 2004 – Surface chemical analysis – Auger electron spectroscopy and X‐ray photoelectron spectroscopy – Guide to the use of experimentally determined relative sensitivity factors for the quantitative analysis of homogeneous materials

ISO 18118 provides guidance on the measurement and use of experimentally determined relative sensitivity factors for the quantitative analysis of homogeneous materials by Auger electron spectroscopy (AES) and X‐ray photoelectron spectroscopy (XPS). This article provides a brief summary of this International Standard. Copyright © 2005 John Wiley & Sons, Ltd.     

辉光放电质谱法定量测定重掺晶体硅中替位碳含量

采用辉光放电质谱法测定单晶硅中替位碳含量,通过优化仪器工作条件,得到最佳放电参数.利用低温傅里叶变换红外光谱法对呈梯度的四个单晶硅片中替位碳含量进行赋值,将辉光放电质谱法测得替位碳强度与硅的离子束比与赋值结果作工作曲线,计算得到相对灵敏度因子(RSFcal)为1.19.在优化过的工作条件下,用辉光放电质谱法测未知样,用...     

气体色谱分析的多图谱归一定量法和气体组分的相对校正因子

本文报道一种扩展的气相色谱归一化定量分析方法，使两台或两台以上色谱仪对同一样品的诸多组分所完成的多张色谱力痛应用归一定量法进行计算，从而在进行多组分测定（尤其是气体样品的分析）时大大减少工作量，本方法的关键是样品中某一组分在多张图谱中均有分离很好的峰。     

Restrictions on the degree spectra of algebraic structures

We construct the degree b ≤ 0″ admitting no algebraic structure with degree spectrum {x: x ? b}. Moreover, we solve Miller’s problem of distinguishing incomparable degrees by the spectra of linear orderings.