Global mapping of rat plasma proteins with a native proteomic approach using nondenaturing micro 2DE and quantitative LC‐MS/MS

Plasma samples from adult male rats were separated by nondenaturing micro 2DE and a reference gel was selected, on which 136 CBB‐stained spots were numbered and subjected to in‐gel digestion and quantitative LC‐MS/MS. The analysis provided the assignment of 1–25 (average eight) non‐redundant proteins in each spot and totally 199 proteins were assigned in the 136 spots. About 40% of the proteins were detected in more than one spot and 15% in more than ten spots. We speculate this complexity arose from multiple causes, including protein heterogeneity, overlapping of protein locations and formation of protein complexes. Consequently, such results could not be appropriately presented as a conventional 2DE map, i.e. a list or a gel pattern with one or a few proteins annotated to each spot. Therefore, the LC‐MS/MS quantity data was used to reconstruct the gel distribution of each protein and a library containing 199 native protein maps was established for rat plasma. Since proteins that formed a complex would migrate together during the nondenaturing 2DE and thus show similar gel distributions, correlation analysis was attempted for similarity comparison between the maps. The protein pairs showing high correlation coefficients included some well‐known complexes, suggesting the promising application of native protein mapping for interaction analysis. With the importance of rat as the most commonly used laboratory animal in biomedical research, we expect this work would facilitate relevant studies by providing not only a reference library of rat plasma protein maps but a means for functional and interaction analysis.     

溶剂热法合成UiO-66金属有机框架限域的钴取代磷钼酸及其催化烯烃环氧化性能

金属有机框架材料是一类新型晶体孔性材料,在气体储存、物质分离、非线性光学及催化等领域中具有潜在应用价值.其中,基于锆氧簇和有机配体构筑的锆基金属有机框架材料(ZrMOFs)因其具有更高的结构稳定性而备受关注.研究表明,将多金属氧酸盐(POM)负载在ZrMOFs载体上能够获得一类新型复合材料催化剂.这类材料具有可调控的酸性和氧化还原性,已在一些固体酸催化及选择氧化(包括烯烃环氧化)等反应中表现出优异的催化性能.多金属氧酸盐通常可以通过简单的浸渍法引入到ZrMOFs载体上,但这种方法制备的催化剂普遍存在活性组分分散不均匀且易于在液相催化反应过程中发生活性组分流失的问题.因此,当前的研究重点主要集中在如何通过简单有效的制备方法获得结构更加稳定、性能更加优异的复合材料催化剂.近期,国内外多个研究小组分别报道了采用溶剂热法能够一步合成出POM@ZrMOFs复合材料,这类材料的主要特点是POM团簇能够均匀的分散在ZrMOFs孔道中,从而使其在氧化脱硫及烯烃选择氧化等反应中表现出更高的稳定性.考虑到POMs及ZrMOFs种类和结构的多样性,可以预期这类复合材料的合成及催化性能研究仍有很大的发展空间.本文采用溶剂热法将磷钼酸(PMo12)及钴取代磷钼酸(PMo11Co)限域在一类ZrMOFs材料(UiO-66)的孔道中,得到了两种复合材料催化剂,分别记为PMo12@UiO-66和PMo11Co@UiO-66.通过以叔丁基过氧化氢(t-BuOOH)为氧化剂烯烃环氧化反应考察了其催化性能.相较于PMo12@UiO-66,含有钴取代磷钼酸的PMo11Co@UiO-66杂化材料表现出了更高的催化活性和稳定性.催化剂经简单的过滤和洗涤后即可循环使用多次,且催化性能基本保持不变.值得一提的是,PMo11Co@UiO-66对多种类型烯烃的环氧化反应均表现出较高的催化活性和环氧选择性.例如,在加入自由基抑制剂对二苯酚后,柠檬烯选择性氧化为柠檬烯-1,2-环氧化物的选择性可以达到91%,性能明显优于文献中报道的其它类型催化剂.此外,溶剂种类对PMo11Co@UiO-66的催化活性有着显著的影响,在极性相对较强的乙醇、乙腈等溶剂中,催化剂的活性较低;在极性较弱的甲苯、氯仿,四氯化碳等溶剂中,催化剂的活性则相对较高.溶剂极性的差异会影响反应物分子与催化剂活性中心的接触情况,继而对催化剂的活性产生较大影响.采用X射线衍射、氮吸附-脱附、X射线光电子能谱、傅立叶变换红外光谱(FT-IR)等手段对催化反应前后的PMo11Co@UiO-66催化剂进行了表征.结果表明,在溶剂热法合成的杂化材料催化剂中,引入的POM团簇能够均匀的分散在UiO-66框架材料的孔道和笼中;催化剂反应前后的组成与结构没有发生明显的变化.结合相关文献报道的结果,可以认为杂原子Co的引入能够产生类似于Co–O–Mo的新的活性中心,从而使PMo11Co@UiO-66表现出更高的催化活性.催化剂的高稳定性应主要归因于UiO-66框架对PMo11Co团簇的空间限域作用.这种空间限域作用能够使PMo11Co团簇被封装在UiO-66的八面体笼中,且二者之间还存在着较强的金属-载体间相互作用.在后续的工作中,我们还将继续深入研究PMo11Co@UiO-66催化剂的活性中心性质及其对分子氧的活化能力,加深对催化作用机制等问题的理解,进一步扩大这类复合材料催化剂的应用范围.     

Probing structural stability of double-walled carbon nanotubes at high non-hydrostatic pressure by Raman spectroscopy

Theoretical calculations predict that the collapse pressure for double-walled carbon nanotubes (DWCNTs) is proportional to 1/R ³, where R is the effective or average radius of a DWCNT. In order to address the problem of CNT stability at high pressure and stress, we performed a resonance Raman study of DWCNTs dispersed in sodium cholate using 532 and 633 nm laser excitation. Raman spectra of the recovered samples show minor versus irreversible changes with increasing I _D/I _G ratio after exposure to high non-hydrostatic pressure of 23 and 35 GPa, respectively. The system exhibits nearly 70% pressure hysteresis in radial breathing vibrational mode signals recovery on pressure release which is twice that predicted by theory.     

Attribution of the discrepancy between ELISA and LC-MS/MS assay results of a PEGylated scaffold protein in post-dose monkey plasma samples due to the presence of anti-drug antibodies

High-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) and enzyme-linked immunosorbent assay (ELISA) methods were developed for the quantification of a PEGylated scaffold protein drug in monkey plasma samples. The LC-MS/MS method was based on the extraction of the therapeutic protein with a water-miscible organic solvent and the subsequent trypsin digestion of the extract followed by the detection of a surrogate peptide. The assay was linear over a range of 10-3,000 ng/mL. The ELISA method utilized a therapeutic target-binding format in which the recombinant target antigen was used to capture the drug in the sample, followed by detection with an anti-PEG monoclonal antibody. The assay range was 30-2,000 ng/mL. A correlation study between the two methods was performed by measuring the drug concentrations in plasma samples from a single-dose pharmacokinetic (PK) study in cynomolgus monkeys following a 5-mg/kg subcutaneous administration (n = 4). In the early time points of the PK profile, the drug concentrations obtained by the LC-MS/MS method agreed very well with those obtained by the ELISA method. However, at later time points, the drug concentrations measured by the LC-MS/MS method were consistently higher than those measured by the ELISA method. The PK parameters calculated based on the concentration data showed that the two methods gave equivalent peak exposure (C(max)) at 24-48 h. However, the LC-MS/MS results exhibited about 1.53-fold higher total exposure (AUC(tot)) than the ELISA results. The discrepancy between the LC-MS/MS and ELISA results was investigated by conducting immunogenicity testing, anti-drug antibody (ADA) epitope mapping, and Western blot analysis of the drug concentrations coupled with Protein G separation. The results demonstrated the presence of ADA specific to the engineered antigen-binding region of the scaffold protein drug that interfered with the ability of the drug to bind to the target antigen used in the ELISA method. In the presence of the ADAs, the ELISA method measured only the active circulating drug (target-binding), while the LC-MS/MS method measured the total circulating drug. The work presented here indicates that the bioanalysis of protein drugs may be complicated owing to the presence of drug-binding endogenous components or ADAs in the post-dose (incurred) samples. The clear understanding of the behavior of different bioanalytical techniques vis-à-vis the potentially interfering components found in incurred samples is critical in selecting bioanalytical strategies for measuring protein drugs.     

A Hermite WENO reconstruction-based discontinuous Galerkin method for the Euler equations on tetrahedral grids

A Hermite WENO reconstruction-based discontinuous Galerkin method RDG(P₁P₂), designed not only to enhance the accuracy of discontinuous Galerkin method but also to ensure linear stability of the RDG method, is presented for solving the compressible Euler equations on tetrahedral grids. In this RDG(P₁P₂) method, a quadratic polynomial solution (P₂) is first reconstructed using a least-squares method from the underlying linear polynomial (P₁) discontinuous Galerkin solution. By taking advantage of handily available and yet invaluable information, namely the derivatives in the DG formulation, the stencils used in the reconstruction involve only von Neumann neighborhood (adjacent face-neighboring cells) and thus are compact and consistent with the underlying DG method. The final quadratic polynomial solution is then obtained using a WENO reconstruction, which is necessary to ensure linear stability of the RDG method. The developed RDG method is used to compute a variety of flow problems on tetrahedral meshes to demonstrate its accuracy, efficiency, robustness, and versatility. The numerical experiments demonstrate that the developed RDG(P₁P₂) method is able to maintain the linear stability, achieve the designed third-order of accuracy: one order accuracy higher than the underlying DG method without significant increase in computing costs and storage requirements.     

Synthesis of Beta/MCM-41 composite molecular sieve with high hydrothermal stability in static and stirred condition

Beta/MCM-41 micro/mesoporous composite materials have been prepared through assembly of zeolite Beta nanoclusters and their hydrolysis products in the presence of CTAB under static or stirred conditions. The resulting materials were characterized by powder XRD, TEM and nitrogen adsorption-desorption. Hydrothermal stability of the obtained Beta/MCM-41 composites was evaluated by boiling in distilled water for different periods of time under refluxing. All materials exhibit very high hydrothermal stability.     

两种钒配合物的合成、表征及与Ct-DNA作用研究

合成了两种钒-邻香草醛衍生物配合物[VO2(C10H11O3N)](HOCH2CH2NH3) (1)和VO(C8H8O3N)2 (2); 用FT-IR和X-ray单晶衍射对它们的晶体结构进行了表征; 用紫外吸收光谱法、荧光光谱法、循环伏安法、粘度法等分析了两种配合物与小牛胸腺DNA (Ct-DNA)的作用; 结果表明配合物1以非插入方式与Ct-DNA作用, 配合物2则以插入方式与Ct-DNA作用.     

沸石分子筛的生成机理与晶体生长(Ⅻ)——ZSM-5沸石生成过程中液相硅酸根离子聚合态的研究

自从1964年Lentz等人提出三甲基硅烷化(TMS)方法研究硅酸盐结构后,人们意识到这种方法能够较真按着地反映硅酸盐结构及聚合状态。又由于硅烷化所得的衍生物(硅酯)易溶于有机溶剂,可以采用多种方法进行分析鉴定。本文应用TMS-GLC及TMSGPC二种方法研究了ZSM-5沸石生成过程中液相硅酸根离子聚合状态的变化。     

MoO3 Nanobelt-Modified HMCM-49 Zeolite with Enhanced Dispersion of Mo Species and Catalytic Performance for Methane Dehydro-Aromatization

The methane dehydro-aromatization reaction (MDA) is a promising methane valorization process due to the conversion of methane to value-added aromatics (benzene, toluene and naphthalene). However, one of the major disadvantages of utilizing zeolite in MDA is that the catalyst is rapidly inactivated due to coke formation, which eventually causes the activity and aromatic selectivity to decrease. Consequently, the process is not conducive to large-scale industrial applications. The reasonable control of Mo site distribution on the zeolite surface is the key factor for partially inhibiting the coking of the catalyst and improving stability. Here, MoO₃ nanobelts can be used for alternative Mo precursors to prepare MDA catalysts. Catalysts modified with MoO₃ nanobelts present higher activity (13.4%) and benzene yield (9.2%) than those catalysts loaded with commercial MoO₃.     

Mineralogical changes of bioapatite in femoral bones of mice during pregnancy

Mineralogical changes and solubility of bioapatite in mice cortical bones (2- and 5 months old) were investigated by Raman spectroscopy and inductively coupled plasma spectrometry in this study. The Raman analyses show that the full width at half maximum values of the 960?cm^?1 peak exhibit a slight increase during mouse pregnancy, which suggests slightly decreasing crystallinity. Additionally, aging significantly increases the solubility of bone bioapatite. The 1070?cm^?1 peak indicates the enriched carbonate incorporation during aging from 2 to 5 months. The elevated solubility of bioapatite and low bone density are consistent with the low crystallinity of bioapatite.