A novel method for analyzing formalin-fixed paraffin embedded (FFPE) tissue sections by mass spectrometry imaging

Significant advances have been made in the past decade in the field of mass spectrometry imaging (MS imaging). It is a relatively unestablished technique aimed at direct, high-sensitive and spatially exclusive detection of biological molecules from the surface of tissue sections, so that semi-quantitative distribution map of the analyte can be reconstituted from the mass spectra obtained. There is tremendous potential in its application especially in clinical field, such as biomarker discovery or pharmacokinetic study. However, vast majority of the work has been performed on frozen tissue sections, while it remains generally unpractical to produce frozen sections with clinically resected tumor samples. Here we report our novel sample preparation technique that enabled MS imaging from formalin-fixed paraffin embedded (FFPE) tissue section, including retrospective archive as old as 11 years. FFPE sections were first dewaxed with pre-warmed xylene, and exposed tissue surface was enzymatically digested in nanoliter scale droplets to retain analyte localization. As a result, we succeeded in obtaining MS images of peptide peaks derived from several proteins, identified by MS/MS analysis, using ovarian cancer FFPE sections. The qualities of mass spectra obtained by this method were not significantly different from those obtained from frozen sections. By this, we opened the door to retrospective study of past clinical cases in aim to discover molecular biomarker.     

Ultra-High Molecular Weight Polyethylene with Reduced Fusion Defects and Improved Mechanical Properties by Liquid Paraffin

Products made of ultra-high molecular weight polyethylene (UHMWPE) have a tendency to contain fusion defects, arising during the processing of the reactor powder. These defects have been implicated previously in failures of UHMWPE load-bearing surfaces in knee and hip prostheses. To minimize the fusion defects of UHMWPE products, the low molecular weight substance liquid paraffin (LP) was blended with UHMWPE. Our hypothesis was that the addition of LP could minimize structural defects and thus improve the properties of consolidated UHMWPE. The morphology and property of UHMWPE blends with LP were investigated by SEM, DMA, and stress relaxation. The addition of small amounts of LP improved tensile strength, the elongation at break, and friction and wear properties of UHMWPE, presumably due to structural defect elimination through reducing entanglements and enhancing the chain mobility of UHMWPE.     

A technique for relative quantitation of cancer biomarkers in formalin‐fixed,paraffin‐embedded (FFPE) tissue using stable‐isotope‐label based mass spectrometry imaging (SILMSI)

We developed a novel technique for the relative quantitation of pairs of cancer biomarkers in formalin‐fixed paraffin‐embedded (FFPE) tissue. The method utilizes stable isotope labeled (SIL) chromogens deposited during the standard immunohistochemistry (IHC) tissue staining process. The labeled chromogens are precipitated on tissue enzymatically using the standard IHC protocols. The tissue is then imaged with matrix‐free laser desorption ionization time‐of‐flight mass spectrometry, and peak intensities of reporter ions are used to estimate the relative quantitation of protein biomarkers across the tissue. The relative abundance of two breast cancer biomarkers, estrogen receptor (ER) and progesterone receptor (PgR), were quantitated using their ratio of expression in xenograft models, and the ratios were found to be reproducible both within and across serial sections. The relative quantification of multiple biomarkers in situ across a single tissue section adds an additional dimension in cancer histological evaluation by allowing a visual and statistical assessment of tumor heterogeneity. Copyright © 2015 John Wiley & Sons, Ltd.     

添加碱金属助剂对负载型铂锡催化剂长链烷烃脱氢反应性能的影响

 采用微型催化反应装置,结合氢化学吸附、吡啶吸附的红外光谱、热重分析和程序升温还原等物理化学手段,研究了添加碱金属助剂对负载型Pt－Sn／γ－Al2O3催化剂的长链烷烃（C10～C13）脱氢反应性能、表面酸性、金属表面性质以及负载组分与载体之间相互作用的影响．发现添加一定量的Li＋和Na＋可以减少催化剂的积炭量,提高催化剂的金属表面裸露度,从而改善催化剂的脱氢反应稳定性．而添加碱性较强的K＋和Cs＋虽可以提高催化剂的抗积炭性能,但破坏了Pt－Sn－Al2O3之间的相互作用,使锡组分易被还原,催化剂的活性表面减小,从而抑制了催化剂的脱氢反应活性．     

Effects of soft X‐ray radiation damage on paraffin‐embedded rat tissues supported on ultralene: a chemical perspective

Radiation damage is an important aspect to be considered when analysing biological samples with X‐ray techniques as it can induce chemical and structural changes in the specimens. This work aims to provide new insights into the soft X‐ray induced radiation damage of the complete sample, including not only the biological tissue itself but also the substrate and embedding medium, and the tissue fixation procedure. Sample preparation and handling involves an unavoidable interaction with the sample matrix and could play an important role in the radiation‐damage mechanism. To understand the influence of sample preparation and handling on radiation damage, the effects of soft X‐ray exposure at different doses on ultralene, paraffin and on paraffin‐embedded rat tissues were studied using Fourier‐transform infrared (FTIR) microspectroscopy and X‐ray microscopy. Tissues were preserved with three different commonly used fixatives: formalin, glutaraldehyde and Karnovsky. FTIR results showed that ultralene and paraffin undergo a dose‐dependent degradation of their vibrational profiles, consistent with radiation‐induced oxidative damage. In addition, formalin fixative has been shown to improve the preservation of the secondary structure of proteins in tissues compared with both glutaraldehyde and Karnovsky fixation. However, conclusive considerations cannot be drawn on the optimal fixation protocol because of the interference introduced by both substrate and embedding medium in the spectral regions specific to tissue lipids, nucleic acids and carbohydrates. Notably, despite the detected alterations affecting the chemical architecture of the sample as a whole, composed of tissue, substrate and embedding medium, the structural morphology of the tissues at the micrometre scale is essentially preserved even at the highest exposure dose.     

Experimental research in the phase change materials based on paraffin and expanded perlite

In this study, paraffin (PA)/expanded perlite (EP) form-stable phase change material (PCM) was first fabricated using the direct impregnation method without vacuum treatment. Absorptive capacity results showed that the PA/EP composite can obtain good absorptive capacity with the temperature 80 °C and the time 2 h. Compared with the water absorption of EP, the decrease in the water absorption of PA/EP form-stable proved that the absorption of PA into porous EP has been carried out successfully. Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) results show that paraffin can be well impregnated into EP pores and has good compatibility with it. Differential scanning calorimetry (DSC) results reveal that paraffin/EP composite PCM has melting temperature and latent heat of 53.6 °C and 91.3 J/g, respectively. The durability cycles results suggest that form-stable PA/EP PCM shows good durability.     

柴油中的蜡晶成分分析

利用固液分离技术,在冷滤点下-1℃,将柴油中固态成分分离出并得到蜡晶.通过GC-MS对两种柴油的蜡晶成分进行分析,得到柴油中主要成分为正构烷烃、异构烷烃、环烷烃和芳香烃.蜡晶成分中正构烷烃超过40%,异构烷烃占20%左右,环烷烃和芳香烃较少.对比各蜡晶成分,发现环烷烃和芳香烃在相同碳数情况下具有较高的熔点.是柴油蜡晶的晶核部分.     

液膜萃取法回收磷酸体系中的微量镧

通过斜率分析法研究了P204和TOPO从磷酸体系中液液萃取微量镧的反应机制和热力学,推测出一种可能的反应历程和萃合物结构,得到萃取反应式和反应的平衡常数K=104.502,焓变ΔH=-13.02 kJ.mol-1,自由能ΔG=-25.686 kJ.mol-1,熵变ΔS=0.0425kJ.(mol.K)-1。在液液萃取反应机制研究的基础上,采用液膜萃取法进行磷酸体系中微量镧的富集回收研究,考察了载体P204(2%～10%w/w)和TOPO(1%～10%w/w)、表面活性剂磺化聚丁二烯LYF(1%～10%w/w)、内萃取剂HCl(1～5 mol.L-1)和水乳体积比A/O(2:1～7:1)对液膜萃取收率及稳定性的影响。在最优条件下,可回收94.10%～95.94%的镧,并且膜溶胀率为8%～17%,破损率为0.45%～1.93%,能够维持较好的液膜稳定性。研究结果对磷酸中的微量稀土镧回收利用具有一定的参考价值。     

Dielectric relaxation of some heterocyclic compounds in highly viscous media

Dielectric measurements on three heterocyclic compounds namely pyrrolidine, piperidine and 2-acetylpyridine in paraffin oil and paraffin oil + cyclohexane mixtures over the temperature range (294–318 K) at 9.8 GHz have been made. The data have been analysed using the method of Higasiet al and their dependence on macroscopic viscosity has been examined. The effect of solvent viscosity on the dipolar rotational process of the molecules in highly viscous media is also discussed.     

Preparation and evaluation of a stable nanoalumina-paraffin composite: Melting rate investigation using image analysis

New kinds of nanocomposite phase change materials (PCMs) were prepared using various surfactants and surface modification to improve the dispersion of nanoalumina in paraffin. The results showed that only sodium stearoyl lactylate (SSL), could stabilize nanoAl₂O₃ in paraffin. The mechanism of the effect of SSL on the stability of prepared PCMs is discussed. Image analysis showed that addition of nanoparticles has a significant effect on the nanocomposites melting rate, and compared to the pure paraffin, an increasing of 6, 10, 16 and 29% were observed in melting rates of naocomposites composed of 2.5, 5.0, 7.5 and 10.0?wt.% nanoalumina, respectively.