Designer cell-self-implemented labeling of microvesicles in situ with the intracellular-synthesized quantum dots

Cell-derived microvesicles(MVs) are secreted from almost all kinds of mammalian cells into the extracellular space, and play crucial roles in intercellular communication and transporting biomolecules between cells. However, there is a great challenge for visualizing and monitoring of MVs' bio-behaviors due to the limitations of existing labeling methods. Herein, we report the first paradigm of designer cell-self-implemented labeling of MVs secreted from living mammalian MCF-7 cells in situ using the intracellular-synthesized fluorescent quantum dots(QDs) during the formation of MVs. By elaborately coupling intracellular biochemical reactions and metabolism pathways, the MCF-7 cells can be illuminated brightly by intracellular-biosynthesized fluorescent CdSe QDs. Simultaneously, intracellular-synthesized QDs can be in situ encapsulated by the secreted MVs budding from the plasma membrane of the fluorescing cells to label the MVs with an efficiency of up to 89.9%. The whole labeling process skillfully combines designer precise cell-tuned intricate synthesis of CdSe QDs with mild in-situ labeling via cell-selfimplementation just after feeding the cell with suitable chemicals, which is structure-or function-nondestructive and much more straightforward and milder than those by chemical conjugation or indirect encapsulation with conventional fluorogenic labels.     

Carbon Fibers Decorated by Polyelectrolyte Complexes Toward Their Epoxy Resin Composites with High Fire Safety

The achievement of both robust fire-safety and mechanical properties is of vital requirement for carbon fiber(CF) composites.To this end, a facile interfacial strategy for fabricating flame-retardant carbon fibers decorated by bio-based polyelectrolyte complexes(PEC) consisting of chitosan(CH) and ammonium polyphosphate(APP) was developed, and its corresponding fire-retarded epoxy resin composites(EP/(PEC@CF)) without any other additional flame retardants were prepared. The decorated CFs were characterized by SEMEDX, XPS and XRD, indicating that the flame-retardant PEC coating was successfully constructed on the surface of CF. Thanks to the nitrogen-and phosphorous-containing PEC, the resulting composites exhibited excellent flame retardancy as the limiting oxygen index(LOI) increased from 31.0% of EP/CF to 40.5% and UL-94 V-0 rating was achieved with only 8.1 wt% PEC. EP/(PEC8.1@CF) also performed well in cone calorimetry with the decrease of peak-heat release rate(PHRR) and smoke production rate(SPR) by 50.0% and30.4%, respectively, and the value of fire growth rate(FIGRA) was also reduced to 3.41 kW·m~(-2)·s~(-1) from 4.84 kW·m~(-2)·s~(-1), suggesting a considerably enhanced fire safety. Furthermore, SEM images of the burning residues revealed that the PEC coating exhibited the dominant flame-retardant activity in condensed phase via the formation of compact phosphorus-rich char. In addition, the impact strength of the composite was improved, together with no obvious deterioration of flexural properties and glass transition temperature. Taking advantage of the features, the PEC-decorated carbon fibers and the relevant composites fabricated by the cost-effective and facile strategy would bring more chances for widespread applications.     

Zirconium complexes incorporated with asymmetrical tridentate pincer type mono- and di-anionic pyrrolyl ligands: mechanism and reactivity as catalytic precursors

The reactions of Zr(NR(2))(4) (1, R = Me; 2, R = Et) with an asymmetrical tridentate pincer type pyrrole ligand precursor [C(4)H(2)NH(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))] and treatment of the derivatives with either PhNCS or PhNCO have been carried out and characterized. Reacting Zr(NR(2))(4) (1, R = Me; 2, R = Et) with [C(4)H(2)NH(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))] generates Zr[C(4)H(2)N(2-CH(2)N(t)Bu)(5-CH(2)NMe(2))](NR(2))(2) (3, R = Me; 4, R = Et) in high yield along with the elimination of 2 equiv of dimethylamine or diethylamine, respectively. Interestingly, while changing the solvent from Et(2)O to CH(2)Cl(2), the complex Zr[C(4)H(2)N(2-CH(2)N(t)Bu)(5-CH(2)NMe(2))][C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))]Cl (5) is produced by undergoing C-Cl bond cleavage. Furthermore, reaction of either 3 or 4 with 1 or 2 equiv of PhNCS or PhNCO yields Zr[C(4)H(2)N(2-CH(2)N(t)Bu)(5-CH(2)NMe(2))](NMe(2))[PhNC(NMe(2))S] (6), Zr[C(4)H(2)N(2-CH(2)N(t)Bu)(5-CH(2)NMe(2))](NEt(2))[PhNC(NEt(2))O] (7) and Zr[C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))][PhNC(NEt(2))O](3) (8), respectively. All the aforementioned complexes were characterized by (1)H and (13)C NMR spectrometry and the molecular structures of 5, 6, and 8 have been determined by single-crystal X-ray diffractometry. Complexes 4, 5, and 7 initiated the ethylene polymerization in the presence of MAO as the co-catalyst.     

Probing double layer structures of Au (111)-BMIPF6 ionic liquid interfaces from potential-dependent AFM force curves

High quality AFM force curves are presented with detailed potential dependent layering behaviors of the ionic liquid molecules, from which charged interior and neutral exterior layers are distinguished. The electric double layer is confined within the interior layers of one to two molecular size within the potential range of up to 1 V negative of the PZC.     

The effect of inorganic particles on slot die coating of poly(vinyl alcohol) solutions

Among various coating processes, slot die coating belongs to a class of pre-metered coating, in which the coating film thickness can be predetermined. In the past, most research works on slot die coating have focused mainly on polymer solutions; very little information is available using suspensions as coating fluids. In this study, the effect of adding TiO2 and SiO2 in aqueous polyvinyl alcohol (PVA) solutions on slot die coating is investigated. It was found that the stable coating window was enlarged with the addition of particles, and its size increased with solids concentration. This is due to the strong interaction between polymer and particles, resulting in a higher viscosity and surface tension. As a result, the upstream coating bead is more stable and the maximum coating speed is extended to a high value, hence the coating window becomes larger. Although both viscosity and surface tension appear to contribute to the stability of coating flow, the effect of surface tension is more dominant. The surface tension of a suspension with porous particles was higher than one with hard solid particles. Consequently, the coating window obtained with the former was significantly larger than the latter. Flow visualization revealed that under the same operating conditions, the upstream dynamic contact angle for the suspension was smaller than for the aqueous polymer solution. This observation could be related to the stability of the upstream coating bead, and hence the coating window. The experimental flow fields were verified numerically with the aid of a numerical simulation package (Flow-3D).     

蛋白质组学研究中傅立叶变换离子回旋共振质谱数据采集方法的比较

探讨了线性离子阱-傅立叶变换离子回旋共振质谱(LTQ-FT)的数据采集模式对蛋白质组鉴定结果的影响,比较和分析了针对不同复杂程度样本的最佳采集模式.对于α-乳清蛋白4种标准蛋白质酶切肽段混合物的简单体系,在傅立叶变换离子回旋共振腔中选3个最强母离子进行选择离子监测扫描后, 再实施二级碎裂的方法(SIM3) 得到的肽段覆盖率, 分别是直接选10个最强母离子进行二级碎裂(FT10)方法得到的肽段覆盖率的1.5～1.9倍.另外, 对酵母蛋白酶切肽段混合物的复杂体系鉴定时,只采集双电荷和三电荷母离子进行二级扫描的方法(FT10_23)比单电荷、双电荷和三电荷都采集的方法(FT10_123)得到的图谱鉴定成功率提高64.1%.实验还对不同数据采集模式下图谱的特点进行了考察.本研究表明,针对不同复杂程度的样本,应采取不同的质谱数据采集方法.     

正辛醇的γ辐照稳定性及辐解产物分析

在高放射性废液后处理的萃取工艺中,正辛醇被认为是具有应用前景的稀释剂之一,而研究其γ辐射效应对指导其实际应用具有重要意义.本文对N_2环境下γ辐照后的正辛醇进行了紫外-可见(UV-Vis)光谱和傅里叶变换红外(FTIR)光谱研究.结果表明正辛醇在100 kGy以下辐照后化学结构未发生变化,而吸收剂量增至300kGy时有羰基化合物生成.通过色谱(GC)和色质联用(GC-MS)进一步分析了高剂量(600 kGy)辐照后正辛醇的气体及液体辐解产物,发现主要气体产物为H_2,并伴有微量的CO_2和CH_4;主要液体产物为正辛醛,其占未辐解正辛醇的质量百分含量小于1%,并伴有少量正庚烷和8-羟基十五醇.对辐照后正辛醇的化学结构及辐解产物的分析表明,正辛醇在氮气下经γ辐照后,主要发生α碳原子上的C-H键断裂,并伴有β碳原子上的C-C键断裂.此外,抽氢反应也是正辛醇辐解的重要途径.     

一种带吡啶悬臂大环异双核Zn（Ⅱ）-Ni（Ⅱ）配合物的合成、晶体结构及其DNA结合/切割性质

合成了一种带吡啶悬臂的不对称大环异双核金属Zn（Ⅱ）-Ni（Ⅱ）配合物[ZnNi （L）]（ClO₄）₂·H₂O （H₂L=3,3''-（（ethane-1,2-diylbis （（pyridin-2-ylmethyl） azanediyl）） bis （methyl ene）） bis （2-hydroxy-5-methylbenzaldehyde））,通过红外光谱、电喷雾质谱、单晶X射线衍射对其结构进行了表征。结果表明Zn（Ⅱ）和Ni（Ⅱ）的配位环境分别为扭曲的三角锥和正四面体。利用紫外光谱、粘度实验和循环伏安法对该配合物与DNA的相互作用模式进行了研究,结果表明配合物与小牛胸腺DNA （CT-DNA）的结合方式为插入模式,其相应的结合常数K_b=1.05×10⁵ L·mol^-1。另外,该配合物对pBR322 DNA有一定的切割作用。     

大腔体静高压技术的发展及应用

大腔体静高压技术在现代工业和高压科学研究中具有基础性的重要意义,已被广泛应用于工业和科研领域,如超硬材料的合成、凝聚态物质在高温高压极端条件下的行为与物性研究等。经过逾半个世纪的不懈努力,以国产铰链式六面顶压机为代表的大腔体静高压技术与设备取得了长足的发展和丰硕的成果,改变了长期以来我国大腔体静高压技术落后于国外的局面。文章以四川大学高压科学与技术实验室为例,对我国大腔体静高压技术及装置从起步研制到世界领先的发展历程和技术特点进行了介绍。同时,基于典型大腔体静高压技术、装置及主要应用,展望了我国相关领域的发展前景。     

High Efficiency Red Organic Light-Emitting Diodes Based on Microcavity Structure

We demonstrate high efficiency red organic light-emitting diodes （OLEDs） based on a planar microcavity comprised of a dielectric mirror and a metal mirror. The microcavity devices emitted red light at a peak wavelength of 610nm with a full width at half maximum （FWHM） of 25nm in the forward direction, and an enhancement of about 1.3 factor in electroluminescent （EL） efficiency has been experimentally achieved with respect to the conventional noncavity devices. For microcavity devices with the structure of distributed Bragg reflectors （DBR ） /indium-tin-oxide（ITO） /V2O5 /N2N′-di（naphthalene-1-yl）-N2N′-diphenyl-benzidine（NPB ） / 4-（dicy-anomethylene）-2-t-butyl-6（1,1,7,7-tetrame-thyljulolidyl-9-enyl）-4H-pyran（DCJTB）：tris（8-hydroxyquinoline） aluminium （Alq3）/Alq3/LiF/Al, the maximum brightness arrived at 37000cd/m^2 at a current density of 460.0mA/cm^2, and the current efficiency and power efficiency reach 13.7cd/A at a current density of 0.23 mA/cm^2 and 13.31m/W at a current density of 0.04 mA/cm^2, respectively.