PAO10@SiO_(2)纳米胶囊的制备及自润滑环氧树脂摩擦磨损性能

以聚α烯烃-10(PAO10)为芯材、二氧化硅(SiO_(2))为壁材通过模板法及溶胶凝胶法,在水包油(O/W)乳液体系中制备了PAO10@SiO_(2)纳米胶囊,所制备的纳米胶囊呈规则球形,粒径约550 nm,芯材PAO10的质量分数为68.3%。同时,制备了含该纳米胶囊的自润滑环氧树脂复合材料,摩擦磨损实验表明,含10%PAO10@SiO_(2)纳米胶囊的环氧树脂复合材料的摩擦系数和磨损率与纯环氧树脂相比分别降低了58.5%和94.0%,通过摩擦面的扫描电镜表征揭示了纳米胶囊填充的环氧树脂复合材料的自润滑机理。

pH响应型BTA@DME/Cu^(2+)-BTA微胶囊的制备及涂层的防腐性能

文中以天然硅藻土(DME)为微容器,采用真空浸渍法负载苯并三氮唑(BTA)缓蚀剂,同时将具有pH响应性的Cu^(2+)-BTA络合物包覆在BTA@DME外表面,制备了pH响应型BTA@DME/Cu^(2+)-BTA微胶囊。扫描电镜、能谱仪及解络合宏观实验证明了BTA的成功负载以及Cu^(2+)-BTA层的成功包覆,微胶囊中BTA的负载率为44.6%。制备的微胶囊具有pH缓释性,pH为7,Cu^(2+)浓度为60 mmol/L时,形成的Cu^(2+)-BTA络合物结构致密,微胶囊中BTA的释放率低于10%;pH为5和2时,微胶囊中BTA的释放率分别为50%和80%。添加5%BTA@DME/Cu^(2+)-BTA微胶囊的环氧树脂划痕涂层具有最佳防腐效果,在浸泡周期内,阻抗模量越来越高,从浸泡1 d后的2.8×10^(5)Ω·cm^(2)增加到浸泡30 d后的1.36×106Ω·cm^(2)。

自润滑聚合物材料研究进展

润滑失效是导致摩擦运动零部件性能退化的主要原因,自润滑聚合物材料为解决这一问题提供了有效途径。文中综述了自润滑聚合物材料研究进展,对固体纳米粒子填充型自润滑材料、多孔自润滑聚合物材料、微胶囊型自润滑材料3种自润滑聚合物复合材料进行了介绍,重点对微胶囊型自润滑聚合物材料近年来的研究进展进行分析和总结。从自润滑机理、自润滑微胶囊化方法、芯材润滑剂及壁材的种类、自润滑聚合物材料的摩擦磨损性能、减摩耐磨机理等方面进行详细阐述,最后对自润滑聚合物材料的前景进行了展望。

Core-satellite metal-organic framework@upconversion nanoparticle superstructures via electrostatic self-assembly for efficient photodynamic theranostics

The nanoplatforms based on upconversion nanoparticles(UCNPs)have shown great promise in amplified photodynamic therapy(PDT)triggered by near-infrared(NIR)light.However,their practical in vivo applications are hindered by the overheating effect of 980 nm excitation and low utilization of upconversion luminescence(UCL)by photosensitizers.To solve these defects,core-satellite metal-organic framework@UCNP superstructures,composed of a single metal-organic framework(MOF)NP as the core and Nd3+-sensitized UCNPs as the satellites,are designed and synthesized via a facile electrostatic self-assembly strategy.The superstructures realize a high co-loading capacity of chlorin e6(Ce6)and rose bengal(RB)benefitted from the highly porous nature of MOF NPs,showing a strong spectral overlap between maximum absorption of photosensitizers and emission of UCNPs.The in vitro and in vivo experiments demonstrate that the dual-photosensitizer superstructures have trimodal(magnetic resonance(MR)/UCL/fluorescence(FL))imaging functions and excellent antitumor effectiveness of PDT at 808 nm NIR light excitation,avoiding the laser irradiation-induced overheating issue.This study provides new insights for the development of highly efficient PDT nanodrugs toward precision theranostics.

Characteristics of plankton Hg bioaccumulations based on a global data set and the implications for aquatic systems with aggravating nutrient imbalance

The bioaccumulation of mercury(Hg)in aquatic ecosystem poses a potential health risk to human being and aquatic organism.Bioaccumulations by plankton represent a crucial process of Hg transfer from water to aquatic food chain.However,the current understanding of major factors affecting Hg accumulation by plankton is inadequate.In this study,a data set of 89 aquatic ecosystems worldwide,including inland water,nearshore water and open sea,was established.Key factors influencing plankton Hg bioaccumulation(i.e.,plankton species,cell sizes and biomasses)were discussed.The results indicated that total Hg(THg)and methylmercury(MeHg)concentrations in plankton in inland waters were significantly higher than those in nearshore waters and open seas.Bioaccumulation factors for the logarithm of THg and MeHg of phytoplankton were 2.4–6.0 and 2.6–6.7 L/kg,respectively,in all aquatic ecosystems.They could be further biomagnified by a factor of 2.1–15.1 and 5.3–28.2 from phytoplankton to zooplankton.Higher MeHg concentrations were observed with the increases of cell size for both phyto-and zooplankton.A contrasting trend was observed between the plankton biomasses and BAF_(MeHg),with a positive relationship for zooplankton and a negative relationship for phytoplankton.Plankton physiologic traits impose constraints on the rates of nutrients and contaminants obtaining process from water.Nowadays,many aquatic ecosystems are facing rapid shifts in nutrient compositions.We suggested that these potential influences on the growth and composition of plankton should be incorporated in future aquatic Hg modeling and ecological risk assessments.

Study of K^+ doping on structure and properties of γ-Ce_2S_3

In this study,K+-doped γ-Ce2 S3 was successfully prepared via a gas-solid reaction method using CeO2,K2 CO3,and CS2 as raw materials.The effects of the suitable sulfide system and different molar ratios of K to Ce(nK/Ce=0-0.30) on the phase composition,crystal structure,chromaticity and thermal stability ofγ-Ce2 S3 were systematically investigated.Pure γ-Ce2 S3 was obtained by calcining the doped samples at840℃ for 150 min.After calcination at the same temperature the undoped K+samples exhibit a pure α-phase.Samples with a K/Ce molar ratio(nK/Ce) of 0.10-0.25 comprise only the γ-phase;and when nK/Ce exceeds 0.25,a new heterogeneous phase,KCeS2,emerges.For values of nK/Ce in the range of0-0.25,the γ-Ce2 S3 lattice parameters gradually increases with increasing K+ content.When nK/Ceexceedes 0.25,the lattice parameters remains unchanged.As nK/Ce increased,the synthesized color gradually changes from red to orange—red and finally,to yellow.The redness value a* reaches the maximum(L*=33.86,a*=36.68,b*=38.15) when nK/Ce=0.10,The nK/Ce=0.10 composition continues to exhibit the y-phase after heat treatment at 420℃ for 10 min in air.The K+doping fills the internal vacancies of γ-Ce2 S3 and formed a solid solution,which is beneficial for the stability of its lattice,thus improving the thermal stability of γ-Ce2 S3(from 350 to 420℃).

高脂饮食对小鼠胃蛋白质组表达水平的影响

以高脂饮食小鼠为模型,多角度分析高脂饮食对小鼠胃蛋白组表达的影响。实验小鼠(C57BL/6)随机分配两组,实验组食用高脂饲料,对照组食用正常饲料,喂养110d后,把胃组织分为前胃、胃体和胃窦3个区分别进行蛋白质谱鉴定,随后比较两组实验的蛋白表达谱,分别筛选两组之间的差异蛋白以及胃分区的差异蛋白(差异倍数≥2),并对其进行GO富集及蛋白相互作用网络分析。对照组和实验组共鉴定到9 307种蛋白,筛选特异性肽段≥1且重复实验中至少鉴定到2次的蛋白,最后剩余4 066种蛋白,其中对照组3654种,实验组3832种。进一步从生物功能角度整体分析了胃组织的蛋白表达谱,结果发现实验组小鼠胃组织中高表达蛋白主要参与蛋白稳定和运输等生物学过程。而在对胃分区差异蛋白的功能分析表明,前胃主要参与角质化和肌动蛋白组装相关生物学过程,且受饮食影响程度较小;胃体和胃窦主要执行消化功能,高脂饮食后对胃的基本消化功能并无显著影响,但与对照组相比,参与蛋白转运和脂肪代谢相关生物学过程的蛋白显著高表达。