Assembly of Semiconductor Nanorods into Circular Arrangements Mediated by Block Copolymer Micelles

The collective properties of ordered ensembles of anisotropically shaped nanoparticles depend on the morphology of organization. Here, we describe the utilization of block copolymer micelles to bias the natural packing tendency of semiconductor nanorods and organize them into circularly arranged superstructures. These structures are formed as a result of competition between the segregation tendency of the nanorods in solution and in the polymer melt; when the nanorods are highly compatible with the solvent but prefer to segregate in the melt to the core-forming block, they migrate during annealing toward the core–corona interface, and their superstructure is, thus, templated by the shape of the micelle. The nanorods, in turn, exhibit surfactant-like behavior and protect the micelles from coalescence during annealing. Lastly, the influence of the attributes of the micelles on nanorod organization is also studied. The circular nanorod arrangements and the insights gained in this study add to a growing list of possibilities for organizing metal and semiconductor nanorods that can be achieved using rational design.     

FTIR spectroscopic investigation and modeling of solute / polymer interactions in the hydrated state

Attenuated total reflectance infrared spectroscopy was used to investigate possible interactions during transport of oxprenolol . HCl, bovine serum albumin, α-chymotrypsin, and fibrinogen through poly(acrylic acid) and its random copolymeric gels. Carbonyl and carboxylate ion peak shifts were used to identify drug/gel binding due to electrostatic and hydrogen bond interactions between the polymer carrier and the drugs tested. These findings were used to interpret the decrease in calculated diffusion coefficients of drugs diffusing through these gels and the associated hindering of drug transport. A model was developed to analyze this transport process as a function of the binding heat of the drug with the polymer.     

Glucoamylase absorption and desorption process

This paper reports the study of glucoamylase absorption and desorption processes on spherical particles constituting acrylic supports. The kinetic (reaction order, half-life of the reaction, reaction rate constant), and thermodynamic parameters (activation energy, pre-exponential factor) of the glucoamylase immobilization reaction dynamics inside the acrylic supports have been studied. Hindrance of the penetrants (protein molecules), which defeats the polymer's cohesive forces and passes through the diffusional barriers towards the sites available to receive it, denotes the influence of the diffusion phenomena, and might be expressed by the values of the effective diffusion coefficient and of the energetic parameters, as well. The desorption dynamics of glucoamylase in specific buffer concentration gradients and temperature are dependent on the eluent volume and on the protein eluate.     

复方雪上一枝蒿贴剂的研制及体外评价

以雪上一枝蒿甲素(1)的体外透皮量为评价指标,筛选复方雪上一枝蒿膜控型透皮贴剂处方。处方用三乙醇胺调至pH 7.5±0.2,同时加入5%的柠檬烯能有效促进1透过乙烯-醋酸乙烯共聚物膜;体外透裸鼠离体皮肤试验表明,5%的月桂氮(艹卓)酮能显著提高1的透皮量,且贴剂能维持24h稳定释药,与原酊剂相比,透皮速率无显著性差异。     

动态密度泛函理论在嵌段共聚物介观结构模拟中的应用

采用动态密度泛函理论(DDFT)方法对两嵌段和三嵌段共聚物熔体微相分离后的三维介观结构进行了模拟研究，考察了共聚物链长．N—12下组分A、B不同配比的11种两嵌段共聚物和10种三嵌段共聚物，通过等密度面图很好地表述了微相分离后的三维介观结构。通过比较序参数户、自由能F和熵S随时间的变化，发现当组分A与组分B的链节数之比．NA／NB和模拟参数均相同时，两嵌段共聚物熔体比三嵌段共聚物熔体容易发生微相分离，而三嵌段共聚物越不对称，微相分离越容易。     

Retrofitting implant overdenture attachments: A clinical report

The remake of implant-overdenture prostheses on preexisting implants can present the clinician with a challenge, especially when the prosthetic components used initially cannot be replaced. The difficulty of remaking the prosthesis may be further increased by implant attachments designed to be cemented to the implant itself--a feature that complicates future replacement. This clinical report describes the restoration of worn implant attachments using retrofit components.     

St/MMA嵌段共聚反应及制备纳米微孔薄膜

采用阴离子聚合技术合成了苯乙烯(St)和甲基丙烯酸甲酯(MMA)的两嵌段共聚物P(St-b-MMA)，探讨了环己烷／四氢呋喃混合溶剂对聚合的影响，采用FTIR、^13C NMR等表征产物结构及成分，并以P(St-b-MMA)(聚甲基丙烯酸甲酯链段质量分数为0．31)制备了具有纳米孔洞的高分子薄膜。     

Dialysis Treatment Using an Ethylene Vinyl Alcohol Membrane and No Anticoagulation for Chronic Uremic Patients

Abstract: Anticoagulation used in hemodialysis treatment brings with it the risk of hemorrhagic complications and the possible consequences associated with chronic heparin administration. These problems have not been satisfactorily addressed to date. This study examined a new dialysis method that does not require the administration of anticoagulants. Dialysis is performed for 3 h with a continuous infusion of 750 ml of physiological saline solution in predilution mode and using filters made of ethylene vinyl alcohol copolymer membranes. Eleven patients with chronic uremia underwent more than 2,000 dialysis treatments performed with 9 episodes of coagulation of the dialyzer or blood tubings (0.43%). An evaluation of individual treatments revealed a high degree of biocompatibility and only a scanty activation of coagulation. Blood depuration efficacy was very good as evaluated from pretreatment and posttreatment routine blood chemistries. The technique described here represents a simple and effective method for performing regular dialysis treatment and does not require anticoagulant therapy.     

Near-infrared-emissive polymersomes: self-assembled soft matter for in vivo optical imaging

We demonstrate that synthetic soft materials can extend the utility of natural vesicles, from predominantly hydrophilic reservoirs to functional colloidal carriers that facilitate the biomedical application of large aqueous-insoluble compounds. Near-infrared (NIR)-emissive polymersomes (50-nm- to 50-microm-diameter polymer vesicles) were generated through cooperative self assembly of amphiphilic diblock copolymers and conjugated multi(porphyrin)-based NIR fluorophores (NIRFs). When compared with natural vesicles comprised of phospholipids, polymersomes were uniquely capable of incorporating and uniformly distributing numerous large hydrophobic NIRFs exclusively in their lamellar membranes. Within these sequestered compartments, long polymer chains regulate the mean fluorophore-fluorophore interspatial separation as well as the fluorophore-localized electronic environment. Porphyrin-based NIRFs manifest photophysical properties within the polymersomal matrix akin to those established for these high-emission dipole strength fluorophores in organic solvents, thereby yielding uniquely emissive vesicles. Furthermore, the total fluorescence emanating from the assemblies gives rise to a localized optical signal of sufficient intensity to penetrate through the dense tumor tissue of a live animal. Robust NIR-emissive polymersomes thus define a soft matter platform with exceptional potential to facilitate deep-tissue fluorescence-based imaging for in vivo diagnostic and drug-delivery applications.