Aptamer-Functionalized Nanoparticles in Targeted Delivery and Cancer Therapy

Using nanoparticles to carry and delivery anticancer drugs holds much promise in cancer therapy, but nanoparticles per se are lacking specificity. Active targeting, that is, using specific ligands to functionalize nanoparticles, is attracting much attention in recent years. Aptamers, with their several favorable features like high specificity and affinity, small size, very low immunogenicity, relatively low cost for production, and easiness to store, are one of the best candidates for the specific ligands of nanoparticle functionalization. This review discusses the benefits and challenges of using aptamers to functionalize nanoparticles for active targeting and especially presents nearly all of the published works that address the topic of using aptamers to functionalize nanoparticles for targeted drug delivery and cancer therapy.     

Room temperature direct oxidation of benzene to phenol using hydrogen peroxide in the presence of vanadium-substituted heteropolymolybdates

The liquid-phase direct catalytic oxidation of benzene to phenol was studied at room temperature using vanadium-substituted heteropolyacids as catalysts. Glacial acetic acid was employed as the solvent for the first time, while hydrogen peroxide was used as the oxidant. A yield of 26% and a selectivity of 91%, respectively, were obtained. The as-prepared phenol was separated by column chromatography and was characterized by infrared and mass spectrometry. The catalysts have been characterized by elemental analysis, thermal gravimetric analysis, infrared spectroscopy, UV–vis spectroscopy, X-ray diffraction, and ³¹P NMR and ⁵¹V NMR techniques. The effects of various reaction parameters, such as solvent, reaction temperature, reaction time and the amount of hydrogen peroxide used, were studied. The effects of different vanadium species on the catalytic performance were also studied. Glacial acetic acid was found to be the most suitable solvent among the solvents used in present work. An appropriate molar ratio of H₂O₂ to benzene of 1.7, and a favorable reaction time of 100 min were optimized. H₄PMo₁₁VO₄₀·13H₂O was found to be the most active in terms of turnover based on vanadium atom and the most stable catalyst.     

Dielectric loss in porous TiO2

The dielectric loss behavior of TiO₂ was characterized on samples of variable porosity and variable pore size. Pores were formed by two methods: varying the sintering temperature and by the addition of a spherical carbon porogen. Porosities varied from 5.9% to 59.3%. Dielectric loss increased with increasing pore volume in each case. However, dielectric loss increased at a slower rate for porogen induced pores. At equivalent pore volumes, pore surface area volumes were higher than those induced using the porogen. Dielectric loss behavior was shown to vary linearly with pore surface area. Our work demonstrates that large pores reduce free surface area and decrease dielectric loss when compared to similar samples with smaller pores. A new model of porous dielectric loss is proposed that characterizes materials based on generalized free surface area instead of porosity alone. Based on this model, we show that the relative loss of porous dielectrics depends critically on the pore surface area and the loss tangent of the parent dielectric.     

对甲苯磺酸催化合成环己烯

以对甲苯磺酸作催化剂,对环己醇脱水制备环己烯的反应进行研究。考察了影响反应的因素,得出了其最佳的反应条件为:催化剂用量为环己醇质量的4%,反应时间1h,产品收率可达91.90%。     

Comparison of Cu–Al–Ni–Mn–Zr shape memory alloy prepared by selective laser melting and conventional powder metallurgy

This work aimed to investigate and critically analyze the differences in microstructural features and thermal stability of Cu−11.3Al−3.2Ni−3.0Mn−0.5Zr shape memory alloy processed by selective laser melting (SLM) and conventional powder metallurgy. PM specimens were produced by sintering 106−180 µm pre-alloyed powders under an argon atmosphere at 1060 °C without secondary operations. SLM specimens were consolidated through melting 32−106 µm pre-alloyed powders on a Cu−10Sn substrate. Mechanical properties were measured through Vickers hardness testing. Differential scanning calorimetry was conducted to assess the martensitic transformation temperatures. X-ray diffraction patterns were collected to identify the metallurgical phases. Optical and scanning electron microscopy was used to analyze the microstructural features. β′₁ martensite was found, irrespective of the processing route, although coarser martensitic variants were present in PM-specimens. In conventional powder metallurgy samples, intergranular eutectoid constituents and stabilized austenite also formed at room temperature. PM-specimens showed similar average hardness values to the SLM-specimens, albeit with high standard deviation linked to the porosity. The specimens processed by SLM showed reversible martensitic transformation (T₀=171 °C). PM-processed specimens did not show shape memory effects.     

复合驱油菌株提高安塞低渗透油田采收率实验

从安塞油藏环境中分离到两种高产生物表面活性剂的优良驱油菌株,经鉴定为铜绿假单胞菌DN001和枯草芽孢杆菌DN002. 通过室内和现场试验评价了驱油微生物及其复合菌株降低表面张力和界面张力的能力、对原油的乳化性能以及对当地油藏的环境适应性。结果表明,复合菌株发酵液可将水的表面张力从72 mN/m降低到25.1 mN/m,并且发酵液的油水界面活性较高,平衡界面张力为0.954 3 mN/m.筛选的微生物菌体在安塞油田油藏环境中可大量繁殖。室内驱油模拟实验表明,经复合微生物驱替作用后,采收率可提高17.38%,说明筛选的菌株驱油性能较强,微生物驱油室内评价结果为其在安塞油藏现场应用提供了可靠的试验依据。     

住宅楼面活荷载的统计分析及楼板可靠度的分析

根据西安市、包头市多层及高层住宅楼面活荷载的调查结果,对楼面等效均布活荷载进行了统计分析,据此分析了我国钢筋混凝土楼板设计的可靠度水平。在楼面活荷载的等效中,提出房间受荷面积比的概念,并以此考虑活荷载可能出现的不利布置。分析结果说明:我国目前住宅楼面等效均布活荷载的概率特性已发生较大变化,有必要在更大的范围对楼面活荷载进行调查或考证;受荷面积比对楼面等效均布活荷载以及楼板的可靠度均有显著影响,有必要予以考虑;在考虑楼面活荷载的不利布置时,现行国家规范基本能够保证住宅楼板的可靠度。     

微波照射硅钨酸催化合成环己酮乙二醇缩酮

在微波辐射下,以硅钨酸为催化剂、环已烷为带水剂,合成了环已酮乙二醇缩酮。考察了催化剂的用量、反应时间、酮醇物质的量之比、带水剂的用量及微波功率等诸多因素对产品收率的影响。实验表明,在环已酮用量为0.2mol、n（环已酮）：n（乙二醇）=1.0：1.35、催化剂用量为反应物料总质量的2.7％、以15mL环已烷为带水剂、微波功率为500W和反应时间为30min等优化条件下,环已酮乙二醇缩酮的收率可达71．8％。     

综合状态评价技术在状态监测中应用

传统的故障监测技术是基于通频振动幅值的单一参数进行评价,这种方法虽然简单直观,但不能够准确详细地反映机械设备的运行状态,有可能造成误判或漏判。综合状态评价技术是一种多参数、多角度和多尺度的综合状态评价技术,该方法使用频谱各频段的振动烈度作为状态评价参数,将尽可能多的反映状态变化的参量进行综合分析处理,可以客观地反映出振动的主要原因,便于现场人员使用。     

新型连续混配型清洁压裂液体系研究

通过对粘弹性表面活性剂分子结构的分析,筛选出了低温下溶解性能好、易成胶的长链烷基季铵盐表面活性剂VES-1、VES-2,并通过与激活剂(水杨酸钠)、聚合醇等进行配方优化组合,确定了YCQJ-2清洁压裂液稠化剂的配方,同时评价了1.0%～5.0%YCQJ-2清洁压裂液的性能。结果显示,YCQJ-2清洁压裂液稠化剂与清水按照一定比例混合,即可形成粘弹性较好的冻胶,破胶容易,表/界面张力低,对岩心的伤害率低于15.0%,而且可以实现就地连续混配、连续施工,简化了施工程序,节约成本,保护环境。