BACKGROUND & AIMS: OBJECTIVES:The aim of this study was to determine the magnitude of short fiber-reinforced composite resin, with a semi-IPN-polymer matrix, on polymerization resin shrinkage-strain, shrinkage stress and marginal microleakage of the restoration. MATERIALS AND METHODS:Experimental composite FC resin was prepared by mixing 22.5 wt.% of short E-glass fibers, 22.5 wt.% of IPN-resin and 55 wt.% of silane treated silica fillers using a high speed mixing machine. As control material, commercial particulate filler composite resin (PFC) was used. Polymerization shrinkage-strain and stress of the specimens (n=5) were measured using the bonded-disc technique and tensilometer, respectively with respect to time. FC composite and PFC were placed incrementally in class II cavities sized 4 mm x 4 mm x 6 mm (n=8/group) using total-etch adhesive system according to manufacturer's instructions. After the class II restorations were completed, the specimens were finished and polished, thermocycled, stained, sectioned, and viewed under a stereo-microscope for leakage at occlusal/enamel and gingival/dentin margins. The data were analyzed using ANOVA. RESULTS:ANOVA revealed that restorations made from experimental FC composite had a significantly lower shrinkage stress and microleakage than those made from PFC (p<0.05). The data show that gingival margins had higher microleakage than that obtained from occlusal margins of restorations (p<0.05). CONCLUSIONS:The use of short fiber filler with semi-IPN polymer matrix reduced polymerization shrinkage stress and microleakage compared to a conventional restorative composite.

背景与目标：

BACKGROUND & AIMS: :The objective of this study was to synthesize and characterize a thermally responsive polymer-metal nanocomposite system comprised of a solid gold nanoparticle core and thermally responsive interpenetrating polymer network (IPN) shell, which was surface functionalized or PEGylated with a covalently bound linear poly(ethylene glycol) chain layer. Gold nanoparticles (50 nm diameter) were prepared using standard gold chloride and citrate reduction method. These particles were then encapsulated inside of a polyacrylamide (PAAm)/poly(acrylic acid) (PAA) IPN shell via an in situ inverse emulsion polymerization. The surface of the nanocomposite system was then PEGylated via covalent grafting of a linear methoxy-PEG-N-hydroxysuccinimide (M.W. 3400) to the primary amine groups of the PAAm network. Scanning and transmission electron microscopy were used to confirm the successful synthesis and encapsulation of gold nanoparticles within the IPN shell. Dynamic light scattering was used to examine the temperature swelling response of the IPN particles. Zeta-potential analysis was used to confirm the successful PEGylation of the final nanocomposite system.

背景与目标： : 本研究的目的是合成和表征热响应聚合物-金属纳米复合材料体系，该体系由固体金纳米颗粒核和热响应互穿聚合物网络 (IPN) 壳组成，该体系被共价结合的线性聚乙二醇链层表面官能化或聚乙二醇化。使用标准氯化金和柠檬酸盐还原法制备了直径为50 nm的金纳米颗粒。然后通过原位反相乳液聚合将这些颗粒封装在聚丙烯酰胺 (PAAm)/聚 (丙烯酸) (PAA) IPN壳内。然后通过将线性甲氧基-PEG-N-羟基琥珀酰亚胺 (M.W. 3400) 共价接枝到PAAm网络的伯胺基团，使纳米复合体系的表面聚乙二醇化。扫描和透射电子显微镜用于确认金纳米颗粒在IPN壳中的成功合成和封装。动态光散射用于检查IPN颗粒的温度溶胀响应。Zeta电位分析用于确认最终纳米复合材料系统的成功peg化。

BACKGROUND & AIMS: :The aim of the present study was to establish a novel polymeric excipient for liquid nasal dosage forms exhibiting viscosity increasing properties, improved mucoadhesion and stability towards oxidation in solution. In order to achieve this goal, 2-mercaptonicotinic acid was first coupled to l-cysteine by disulfide exchange reaction and after purification directly attached to the polymeric backbone of xanthan gum by carbodiimide mediated amide bond formation. The resulting conjugate was characterized with respect to the amount of coupled ligand, the in situ gelling behavior, mucoadhesive properties and stability towards oxidation. Furthermore, the influence of preactivated polymers on ciliary beat frequency (CBF) of porcine nasal epithelial cells was investigated. Results showed, that 252.52±20.54μmol of the ligand was attached per gram polymer. No free thiol groups could be detected on the polymeric backbone indicating entire preactivation. Rheological investigations of polymer mucus mixtures revealed a 1.7-fold and 2.5-fold enhanced mucoadhesion of entirely preactivated xanthan (Xan-Cys-MNA) compared to thiolated xanthan (Xan-Cys) and unmodified xanthan (Xan). Tensile force evaluation reported a 2.87 and 5.11-fold higher total work of adhesion (TWA) as well as a 1.63 and 2.41-fold higher maximum detachement force of Xan-Cys-MNA compared to Xan-Cys and Xan. In the presence of H2O2 as an oxidizing agent Xan-Cys-MNA showed unlike Xan-Cys no increase in viscosity, indicating high stability towards oxidation. Addition of CaCl2 to Xan-Cys-MNA solutions caused a decrease in viscosity at nevertheless higher total viscosity. Results from CBF studies proved nasal safety for the novel conjugate. According to these results, entirely preactivated thiolated xanthan gum seems to be a promising excipient for nasal dosage forms in order to improve drug bioavailability.

背景与目标： : 本研究的目的是建立一种用于液体鼻剂型的新型聚合物赋形剂，该剂型具有增加粘度的特性，改善的粘膜粘附性和对溶液中氧化的稳定性。为了实现这一目标，首先通过二硫键交换反应将2-巯基丙酸与l-半胱氨酸偶联，并在纯化后通过碳二亚胺介导的酰胺键形成直接连接到黄原胶的聚合物骨架上。所得缀合物的特征在于偶联配体的量，原位胶凝行为，粘膜粘附特性和对氧化的稳定性。此外，还研究了预活化聚合物对猪鼻腔上皮细胞睫状搏动频率 (CBF) 的影响。结果表明，每克聚合物连接252.52 ± 20.54 μ mol配体。在聚合物骨架上未检测到游离的硫醇基团，表明完全预活化。聚合物粘液混合物的流变学研究表明，与硫醇化的黄烷 (Xan-Cys-MNA) 和未改性的黄烷 (Xan) 相比，完全预活化的黄烷 (Xan-Cys-MNA) 的粘膜粘附增强了1.7倍和2.5倍。与Xan-Cys和Xan相比，拉伸力评估报告的粘附力总功 (TWA) 高2.87 5.11倍，Xan-Cys-MNA的最大分离力1.63 2.41倍。在H2O2作为氧化剂的存在下，Xan-Cys-MNA与Xan-Cys不同，粘度没有增加，表明氧化的稳定性很高。在Xan-Cys-MNA溶液中添加CaCl2会导致总粘度较高的情况下粘度降低。CBF研究的结果证明了新型结合物的鼻安全性。根据这些结果，为了提高药物的生物利用度，完全预活化的硫醇化黄原胶似乎是鼻剂型的有希望的赋形剂。

BACKGROUND & AIMS: :Polymer conjugation is an efficient approach to improve therapeutic properties of drugs and biological agents. Since the first synthetic polymer-drug conjugate entered clinical trials in 1994, this technology has undergone notable development for the introduction and study of novel polymers and for the progress in the biological rationale for designing conjugates. Not surprisingly, new polymers, in addition to the best known polyethylene glycol, poly[N-(2-hydroxypropyl)methacrylamide], are continuously conjugated with drugs to achieve biodegradable, stimuli-sensitive and targeted systems in an attempt to prolong blood circulation times and enhance drug concentrations at the intended site of action. This overview focuses on bioconjugates of water-soluble polymers with low molecular weight drugs. Additionally, the most recent achievements in the polymer-drug conjugate field and several promising approaches for the future are discussed.

背景与目标： : 聚合物缀合是改善药物和生物制剂治疗性能的有效方法。自从第一个合成的聚合物-药物缀合物进入临床试验1994年以来，该技术在新型聚合物的引入和研究以及设计缀合物的生物学原理方面取得了显着进展。毫不奇怪，新的聚合物，除了最著名的聚乙二醇，聚 [N-(2-羟丙基) 甲基丙烯酰胺]，不断与药物缀合以实现可生物降解，刺激敏感和靶向系统试图延长血液循环时间并提高药物在预期作用部位的浓度。这一概述集中于水溶性聚合物与低分子量药物的生物缀合物。此外，讨论了聚合物-药物共轭领域的最新成就以及未来的几种有前途的方法。

BACKGROUND & AIMS: :Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F4:Yb,Er and Li(Gd,Y)F4:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF4 shell. The Li(Gd,Y)F4:Yb,Er/LiYF4 and Li(Gd,Y)F4:Yb,Tm/LiYF4 C/S UCNPs exhibit 3.3 and 2.0 times higher UCL intensities than core counterparts, respectively. In addition, NaGdF4:Yb,Tm/NaGdF4:Eu C/S UCNPs are synthesized and they show red emission via energy transfer and migration of Yb3+ → Tm3+ → Gd3+ → Eu3+. The C/S UCNPs are incorporated into bisphenol A ethoxylate diacrylate which is used as a core material of polymer waveguides. The fabricated stripe-type polymer waveguides are highly flexible and transparent (transmittance > 90% in spectral range of 443-900 nm). The polymer waveguides exhibit bright blue, green, and red luminescence, depending on the incorporated UCNPs into the polymer core, under coupling with a near infrared (NIR) laser. Moreover, patterned polymer waveguide-based display devices are fabricated by reactive ion etching process and they realize bright blue-, green-, and red-colored characters under coupling with an NIR laser.

背景与目标： : 展示了芯/壳 (C/S) 结构的上转换纳米磷酸盐 (UCNP) 结合的基于聚合物波导的柔性透明显示器。通过溶液化学路线合成了亮绿色和蓝色的Li(Gd，Y)F4:Yb，Er和Li(Gd，Y)F4:Yb，Tm UCNPs。通过与LiYF4壳层形成C/S结构，它们的上转换发光 (UCL) 强度得到增强。Li(Gd，Y)F4:Yb、Er/LiYF4和Li(Gd，Y)F4:Yb、Tm/LiYF4 C/S UCNPs分别表现出比核心对应物高3.3和2.0倍的UCL强度。此外，合成了NaGdF4:Yb，Tm/NaGdF4:Eu C/S ucnp，它们通过能量转移和Yb3 +  →   Tm3 +  →   Gd3 + →→   Eu3 + 的迁移显示红色发射。将C/S ucnp掺入双酚a乙氧基二丙烯酸酯中，该双酚a乙氧基二丙烯酸酯用作聚合物波导的核心材料。所制造的条纹型聚合物波导是高度柔性和透明的 (在443-900  nm的光谱范围内透射  >  90%)。聚合物波导在与近红外 (NIR) 激光器耦合的情况下，显示出明亮的蓝色，绿色和红色发光，具体取决于掺入聚合物核中的ucnp。此外，图案化的基于聚合物波导的显示设备是通过反应离子蚀刻工艺制造的，它们在与NIR激光器耦合的情况下实现了明亮的蓝色，绿色和红色特征。

BACKGROUND & AIMS: :D-configured poly(D-lactic acid) (D-PLA) and poly(D-2-hydroxy-3-methylbutanoic acid) (D-P2H3MB) crystallized separately into their homo-crystallites when crystallized by precipitation or solvent evaporation, whereas incorporation of L-configured poly(L-2-hydroxybutanoic acid) (L-P2HB) in D-configured D-PLA and D-P2H3MB induced co-crystallization or ternary stereocomplex formation between D-configured D-PLA and D-P2H3MB and L-configured L-P2HB. However, incorporation of D-configured poly(D-2-hydroxybutanoic acid) (D-P2HB) in D-configured D-PLA and D-P2H3MB did not cause co-crystallization between D-configured D-PLA and D-P2H3MB and D-configured D-P2HB but separate crystallization of each polymer occurred. These findings strongly suggest that an optically active polymer (L-configured or D-configured polymer) like unsubstituted or substituted optically active poly(lactic acid)s can act as "a configurational or helical molecular glue" for two oppositely configured optically active polymers (two D-configured polymers or two L-configured polymers) to allow their co-crystallization. The increased degree of freedom in polymer combination is expected to assist to pave the way for designing polymeric composites having a wide variety of physical properties, biodegradation rate and behavior in the case of biodegradable polymers.

背景与目标： : D型聚 (D-乳酸) (D-PLA) 和聚 (D-2-hydroxy-3-methylbutanoic) (D-P2H3MB) 在通过沉淀或溶剂蒸发结晶时分别结晶成其同型微晶，而将L-配置的聚 (L-2-hydroxybutanoic) (L-P2HB) 掺入D-配置的D-PLA中并D-P2H3MB诱导D-配置的D-PLA与D-P2H3MB和L-配置的L-P2HB之间的共结晶或三元立体复合物形成。然而，D-配置的聚 (D-2-hydroxybutanoic) (D-P2HB) 在D-配置的D-PLA和D-P2H3MB中的掺入不会引起D-配置的D-PLA与D-P2H3MB和D-配置的D-P2HB之间的共结晶，但是发生了每种聚合物的单独结晶。这些发现强烈表明，光学活性聚合物 (L型或D型聚合物) (如未取代或取代的光学活性聚乳酸) 可以充当两种相反配置的光学活性聚合物 (两种D型聚合物或两种L型聚合物) 的 “构型或螺旋分子胶” 聚合物) 以使其共结晶。聚合物组合中增加的自由度有望有助于为设计具有多种物理性能，生物降解速率和在可生物降解聚合物的情况下的行为的聚合物复合材料铺平道路。

BACKGROUND & AIMS: :We report the reactive layer-by-layer assembly of amine-reactive polymer multilayers using an azlactone-functionalized polymer and small-molecule diamine linkers. This approach yields cross-linked polymer/linker-type films that can be further functionalized, after fabrication, by treatment with functional primary amines, and provides opportunities to incorporate other useful functionality that can be difficult to introduce using other polyamine building blocks. Films fabricated using poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) and three model nondegradable aliphatic diamine linkers yielded reactive thin films that were stable upon incubation in physiologically relevant media. By contrast, films fabricated using PVDMA and varying amounts of the model disulfide-containing diamine linker cystamine were stable in normal physiological media, but were unstable and eroded rapidly upon exposure to chemical reducing agents. We demonstrate that this approach can be used to fabricate functionalized polymer microcapsules that degrade in reducing environments, and that rates of erosion, extents of capsule swelling, and capsule degradation can be tuned by control over the relative concentration of cystamine linker used during fabrication. The polymer/linker approach used here expands the range of properties and functions that can be designed into reactive PVDMA-based coatings, including functionality that can degrade, erode, and undergo triggered destruction in aqueous environments. We therefore anticipate that these approaches will be useful for the functionalization, patterning, and customization of coatings, membranes, capsules, and interfaces of potential utility in biotechnical or biomedical contexts and other areas where degradation and transience are desired. The proof of concept strategies reported here are likely to be general, and should prove useful for the design of amine-reactive coatings containing other functional structures by judicious control of the structures of the linkers used during assembly.

背景与目标： : 我们报告了使用氮内酯官能化聚合物和小分子二胺接头的胺反应性聚合物多层反应的逐层组装。这种方法产生交联的聚合物/接头型膜，该膜在制造后可以通过用功能性伯胺处理而进一步官能化，并且提供了掺入其他有用的功能的机会，这些功能可能难以使用其他多胺构建模块引入。使用聚 (2-乙烯基-4,4-二甲基氮杂内酯) (PVDMA) 和三种模型不可降解的脂肪族二胺接头制备的薄膜产生的反应性薄膜在生理相关介质中孵育后稳定。相比之下，使用PVDMA和不同量的模型含二硫键的二胺接头cystamine制备的薄膜在正常生理介质中是稳定的，但在暴露于化学还原剂后会迅速腐蚀且不稳定。我们证明了这种方法可用于制造在还原环境中降解的官能化聚合物微胶囊，并且可以通过控制制造过程中使用的胱胺接头的相对浓度来调节侵蚀速率，胶囊溶胀程度和胶囊降解。此处使用的聚合物/接头方法扩展了可设计为基于反应性PVDMA的涂层的性能和功能的范围，包括可在水性环境中降解，侵蚀和遭受触发破坏的功能。因此，我们预计这些方法将有助于在生物技术或生物医学环境以及其他需要降解和瞬态的领域中潜在用途的涂层，膜，胶囊和界面的功能化，图案化和定制。此处报告的概念验证策略可能是一般性的，并且应通过明智地控制组装过程中使用的连接体的结构来证明对包含其他功能结构的胺反应性涂层的设计有用。

BACKGROUND & AIMS: :Monodisperse silica microspheres with bimodal pore-size distribution were proposed as a high performance sorbent for DNA isolation in batch fashion under equilibrium conditions. The proposed sorbent including both macroporous and mesoporous compartments was synthesized 5.1 μm in-size, by a "staged shape templated hydrolysis and condensation method". Hydrophilic polymer based sorbents were also obtained in the form of monodisperse-macroporous microspheres ca 5.5 μm in size, with different functionalities, by a developed "multi-stage microsuspension copolymerization" technique. The batch DNA isolation performance of proposed material was comparatively investigated using polymer based sorbents with similar morphologies. Among all sorbents tried, the best DNA isolation performance was achieved with the monodisperse silica microspheres with bimodal pore size distribution. The collocation of interconnected mesoporous and macroporous compartments within the monodisperse silica microspheres provided a high surface area and reduced the intraparticular mass transfer resistance and made easier both the adsorption and desorption of DNA. Among the polymer based sorbents, higher DNA isolation yields were achieved with the monodisperse-macroporous polymer microspheres carrying trimethoxysilyl and quaternary ammonium functionalities. However, batch DNA isolation performances of polymer based sorbents were significantly lower with respect to the silica microspheres.

背景与目标： : 提出了具有双峰孔径分布的单分散二氧化硅微球作为平衡条件下分批隔离DNA的高性能吸附剂。通过 “分段形状模板化水解和缩合法” 合成了5.1  μ m大小的包含大孔和中孔隔室的吸附剂。通过开发的 “多级微悬浮共聚” 技术，还以尺寸为ca 5.5 μm μ m的单分散-大孔微球的形式获得了基于亲水性聚合物的吸附剂。使用具有相似形态的基于聚合物的吸附剂对所提出材料的分批DNA隔离性能进行了比较研究。在所有尝试的吸附剂中，具有双峰孔径分布的单分散二氧化硅微球可获得最佳的DNA隔离性能。单分散二氧化硅微球内相互连接的中孔和大孔隔室的配置提供了较高的表面积，并降低了关节内的传质阻力，并使DNA的吸附和解吸更加容易。在基于聚合物的吸附剂中，带有三甲氧基甲硅烷基和季铵官能团的单分散-大孔聚合物微球可获得更高的DNA隔离产率。然而，相对于二氧化硅微球，基于聚合物的吸附剂的分批DNA隔离性能明显较低。

BACKGROUND & AIMS: :We developed a technique for constructing light diffusing devices comprised of a flexible shape memory polymer (SMP) cylindrical diffuser attached to the tip of an optical fiber. The devices are fabricated by casting an SMP rod over the cleaved tip of an optical fiber and media blasting the SMP rod to create a light diffusing surface. The axial and polar emission profiles and circumferential (azimuthal) uniformity are characterized for various blasting pressures, nozzle-to-sample distances, and nozzle translation speeds. The diffusers are generally strongly forward-directed and consistently withstand over 8 W of incident IR laser light without suffering damage when immersed in water. These devices are suitable for various endoluminal and interstitial biomedical applications.

背景与目标： : 我们开发了一种用于构造光漫射设备的技术，该设备由连接到光纤尖端的柔性形状记忆聚合物 (SMP) 圆柱形漫射器组成。通过在光纤的劈裂尖端上浇铸SMP棒，并对SMP棒进行介质爆破以产生光漫射表面来制造设备。轴向和极性发射轮廓以及周向 (方位) 均匀性的特征在于各种爆破压力，喷嘴到样品的距离以及喷嘴的平移速度。扩散器通常是强烈的正向方向，并且在浸入水中时始终承受超过8 W的入射IR激光而不会受到损坏。这些设备适用于各种腔内和间隙生物医学应用。

BACKGROUND & AIMS: :Food-grade emulsion gels have attracted increasing attention in food and drug manufacturing, owing to their potential as novel delivery systems for lipophilic bioactive ingredients. Emulsion gels are structurally either a polymeric gel matrix with incorporated emulsion droplets (emulsion-filled gels), or a network of aggregated emulsion droplets (emulsion particulate gels). In this study, a novel emulsion gel was prepared by formulating an oil-in-water (O/W) emulsion stabilized by sanxan alone, followed by heating and cooling treatment, resulting in a structured solid system. Stable O/W type sanxan emulsion gels (SEGs) were obtained at sanxan concentration >0.5% (w/w). Fluorescence microscopy results confirmed the adsorption of sanxan on oil droplet surfaces. The effect of temperature and sanxan/oil concentrations on the rheological and textural properties of the SEGs was evaluated: the SEG containing 1% (w/w) sanxan and 20% (w/w) sunflower oil exhibited excellent rheological and textural properties. Further, the addition of 10 mM Na+ or 5 mM Ca2+ greatly enhanced the thermostability of the SEG. The potential of SEGs as sustained-release delivery systems for β-carotene was also explored. The findings are of great interest for the development of novel delivery systems based on emulsion gels stabilized by sanxan for the sustained release of lipophilic components.

背景与目标： : 食品级乳液凝胶因其作为亲脂性生物活性成分的新型递送系统的潜力而在食品和药品制造中引起了越来越多的关注。乳液凝胶在结构上是具有掺入的乳液液滴 (乳液填充的凝胶) 的聚合物凝胶基质，或者是聚集的乳液液滴 (乳液颗粒凝胶) 的网络。在这项研究中，通过配制单独由sanxan稳定的水包油 (O/W) 乳液，然后进行加热和冷却处理，从而形成结构化的固体体系，制备了一种新型乳液凝胶。在sanxan浓度> 0.5% (W/w) 下获得稳定的O/w型sanxan乳液凝胶 (seg)。荧光显微镜结果证实了sanxan在油滴表面的吸附。评估了温度和sanxan/油浓度对SEG的流变和质地特性的影响: 含有1% (w/w) sanxan和20% (w/w) 葵花籽油的SEG表现出优异的流变和质地特性。此外，添加10 mM Na或5毫米Ca2大大增强了SEG的热稳定性。还探索了SEGs作为 β-胡萝卜素缓释递送系统的潜力。这些发现对于开发基于sanxan稳定的乳液凝胶以持续释放亲脂性成分的新型递送系统具有极大的兴趣。

BACKGROUND & AIMS: :In 1999, Duennebier et al. deployed a hydrophone and geophone below the conjugate depth in the abyssal Pacific, midway between Hawaii and California. Real time data were transmitted for 3 yr over an abandoned ATT cable. These data have been analyzed in the frequency band 1 to 30 Hz. Between 1 and 6 Hz, the bottom data are interpreted as acoustic radiation from surface gravity waves, an extension to higher frequencies of a non-linear mechanism proposed by Longuet-Higgins in 1950 to explain microseisms. The inferred surface wave spectrum for wave lengths between 6 m and 17 cm is saturated (wind-independent) and roughly consistent with the traditional Phillips κ(-4) wave number spectrum. Shorter ocean waves have a strong wind dependence and a less steep wave number dependence. Similar features are found in the bottom record between 6 and 30 Hz. But this leads to an enigma: The derived surface spectrum inferred from the Longuet-Higgins mechanism with conventional assumptions for the dispersion relation is associated with mean square slopes that greatly exceed those derived from glitter. Regardless of the generation mechanism, the measured bottom intensities between 10 and 30 Hz are well below minimum noise standards reported in the literature.

背景与目标： : 1999年，Duennebier等人。在夏威夷和加利福尼亚之间的深海太平洋中，在共轭深度以下部署了水听器和地震检波器。实时数据通过废弃的ATT电缆传输3年。这些数据已在1至30Hz的频带中进行了分析。在1到6Hz之间，底部数据被解释为来自表面重力波的声辐射，这是Longuet-Higgins 1950年提出的用于解释微震的非线性机制的较高频率的扩展。6 m至17厘米之间的波长的推断表面波频谱是饱和的 (与风无关)，并且与传统的Phillips κ(-4) 波数频谱大致一致。较短的海浪具有强烈的风依赖性和较小的陡峭波数依赖性。在6到30Hz之间的底部记录中发现了类似的功能。但这导致了一个谜: 从Longuet-Higgins机制推断出的具有色散关系的常规假设的衍生表面光谱与均方斜率相关，该均方斜率大大超过了从glitter得出的斜率。无论产生机理如何，测得的10至30Hz之间的底部强度都远低于文献中报道的最低噪声标准。

BACKGROUND & AIMS: :Injectable peptide and oligonucleotide biotherapeutics offer great promise for treatment of serious chronic diseases but almost always need further formulation work to increase stability and circulation lifetimes. Covalent attachment of poly(ethylene glycol) (PEG) will increase circulation lifetimes up to a week or so and decrease degradation in favorable cases. Encapsulation in biodegradable polymer microparticles has been highly successful, mostly for peptides to provide sustained release up to several months after injection. Although products are on the market using these technologies, PEGylation and microparticle encapsulation each have drawbacks that prevent more widespread use. When they are combined, the limitations of one technology may be resolved by the other. Work in several laboratories on encapsulation of PEGylated bioactive molecules has revealed a synergy. Activity reduction and restricted circulation lifetimes for PEGylated bioactive agents is addressed by microencapsulation and using a lower PEG molecular weight. Chemical degradation, excessive burst release and limited drug content are typical problems for microparticles that are ameliorated by using PEGylated actives. The case for synergy between PEGylation and microencapsulation is illustrated in this review by work with several proteins and peptides including insulin, and the oligonucleotide therapeutic, pegaptanib.

背景与目标： : 可注射肽和寡核苷酸生物疗法为治疗严重的慢性疾病提供了巨大的前景，但几乎总是需要进一步的配方工作来增加稳定性和循环寿命。聚乙二醇 (PEG) 的共价附着将增加循环寿命长达一周左右，并在有利的情况下减少降解。在可生物降解的聚合物微粒中封装非常成功，主要用于肽在注射后长达数月的持续释放。尽管使用这些技术的产品在市场上销售，但聚乙二醇化和微粒封装各有缺点，无法更广泛地使用。当它们结合在一起时，一种技术的局限性可能会被另一种解决。在几个实验室中有关聚乙二醇化生物活性分子封装的工作揭示了协同作用。通过微囊化和使用较低的PEG分子量来解决聚乙二醇化生物活性剂的活性降低和循环寿命受限的问题。化学降解，过量的爆裂释放和有限的药物含量是微粒的典型问题，这些微粒可以通过使用聚乙二醇化的活性物来改善。本文通过与几种蛋白质和肽 (包括胰岛素和寡核苷酸治疗药物pegaptanib) 的合作，说明了聚乙二醇化与微囊化之间协同作用的情况。

BACKGROUND & AIMS: :Monocrystalline starch nanoparticles were successfully grafted with poly(tetrahydrofuran), poly(caprolactone), and poly(ethylene glycol) monobutyl ether chains using toluene 2,4-diisocyanate as a linking agent. Surface grafting was confirmed using Fourier transform infrared and X-ray photoelectron spectroscopies, differential scanning calorimetry, elemental analysis, and contact angle measurements. Transmission electron microscopy observations of modified starch nanocrystals showed either the individualization of nanoparticles or the formation of a film, depending on the polymer used. It was shown that grafting efficiency decreased with the length of the polymeric chains, as expected. The resulting modified nanoparticles can find applications in the field of co-continuous nanocomposite materials.

背景与目标： : 使用2,4-二异氰酸酯甲苯作为连接剂，成功地将单晶淀粉纳米颗粒与聚 (四氢呋喃)，聚 (己内酯) 和聚 (乙二醇) 单丁基醚链接枝。使用傅里叶变换红外和x射线光电子能谱，差示扫描量热法，元素分析和接触角测量证实了表面接枝。对改性淀粉纳米晶体的透射电子显微镜观察表明，纳米颗粒的个性化或膜的形成取决于所使用的聚合物。结果表明，如预期的那样，接枝效率随聚合物链的长度而降低。所得的改性纳米颗粒可以在共连续纳米复合材料领域找到应用。

BACKGROUND & AIMS: :Polyplexes are now emerging as potentially useful vectors for gene therapy. To improve our understanding of how the chemical structure of the polymer affects the properties of these systems, a series of structurally related polymers, the linear poly(amidoamine)s (PAAs), have been examined for their abilities to form complexes with DNA. Structure-dependent differences in DNA binding are shown by gel electrophoretic retardation of DNA and thermal transition analyses. Two PAAs, NG28 and NG30, stand out as having high affinity DNA binding characteristics, similar to the model homopolypeptide, poly-L-lysine. In addition, differences in complex formation, particle size and surface charge are displayed for the different polymer-DNA systems. Electron microscopy studies showed that the polymers condensed DNA into similar unit structures but only complexes with NG30 did not undergo agglomeration. This was attributed to an excess of complexed polymer forming a shell of uncomplexed polymer chain segments around a condensed DNA-polymer core. The transfection activities of these polymer complexes differ greatly, and some of these differences can be explained in a multifactorial way by the physicochemical and colloidal properties. It is concluded that polymer chemical structure dictates the apparent affinity of DNA binding, and also several of the important colloidal characteristics of the resulting complexes.

背景与目标： : Polyplexes现在正在成为基因治疗的潜在有用载体。为了增进我们对聚合物的化学结构如何影响这些系统性能的理解，已经研究了一系列结构相关的聚合物，即线性聚 (酰胺胺) s (PAAs)，以了解它们与DNA形成复合物的能力。DNA结合的结构依赖性差异通过DNA的凝胶电泳延迟和热转变分析显示。两种PAAs NG28和NG30具有高亲和力的DNA结合特性，类似于模型的同多肽，聚-L-赖氨酸。此外，对于不同的聚合物-DNA系统，还显示出复合物形成，粒径和表面电荷的差异。电子显微镜研究表明，聚合物将DNA浓缩成相似的单元结构，但只有与NG30的配合物才不会发生团聚。这归因于过量的络合聚合物在缩合的DNA聚合物核周围形成了未络合的聚合物链段的壳。这些聚合物配合物的转染活性差异很大，其中一些差异可以通过物理化学和胶体性质以多因素方式解释。结论是，聚合物化学结构决定了DNA结合的表观亲和力，以及所得复合物的一些重要胶体特征。

BACKGROUND & AIMS: :Words forming a continuous story were presented to 9 subjects at frequencies ranging from 5 to 30 Hz, determined individually to render comprehension easy, effortful, or practically impossible. We identified a left-hemisphere neural network sensitive to reading performance directly from the time courses of activation in the brain, derived from magnetoencephalography data. Regardless of the stimulus rate, communication within the long-range neural network occurred at a frequency of 8-13 Hz. Our coherence-based detection of interconnected nodes reproduced several brain regions that have been previously reported as active in reading tasks, based on traditional contrast estimates. Intriguingly, the face motor cortex and the cerebellum, typically associated with speech production, and the orbitofrontal cortex, linked to visual recognition and working memory, additionally emerged as densely connected components of the network. The left inferior occipitotemporal cortex, involved in early letter-string or word-specific processing, and the cerebellum turned out to be the main forward driving nodes of the network. Synchronization within a subset of nodes formed by the left occipitotemporal, the left superior temporal, and orbitofrontal cortex was increased with the subjects' effort to comprehend the text. Our results link long-range neural synchronization and directionality with cognitive performance.

背景与目标： : 形成连续故事的单词以5至30Hz的频率呈现给9个主题，分别确定以使理解变得容易，费力或几乎不可能。我们从脑磁图数据中直接从大脑激活的时间过程中确定了对阅读性能敏感的左半球神经网络。无论刺激速率如何，远程神经网络内的通信都以8-13Hz的频率发生。基于传统的对比估计，我们对互连节点的基于一致性的检测再现了几个大脑区域，这些区域以前被报道为在阅读任务中处于活动状态。有趣的是，通常与语音产生相关的面部运动皮层和小脑，以及与视觉识别和工作记忆相关的眶额皮层，还成为网络中紧密连接的组件。参与早期字母字符串或特定单词处理的左下枕颞叶皮层和小脑被证明是网络的主要向前驱动节点。随着受试者理解文本的努力，由左枕颞，左上颞和眶额叶皮层形成的节点子集内的同步增加。我们的结果将远程神经同步和方向性与认知表现联系起来。