Controlled drug release of silicone‐based adhesive‐containing cross‐linked siloxane powders as a reservoir

We prepared pressure‐sensitive adhesive (PSA)‐containing cross‐linked siloxane powders (CS) as a reservoir for a transdermal drug delivery system (TDDS) and evaluated their sustained drug‐release properties. PSA, as a patch‐type adhesive, was synthesized by a hydrosilylation reaction of vinyl‐terminated polysiloxanes with hydrogen‐terminated polydimethylsiloxanes. CS was also prepared via a hydrosilylation process with vinyl‐terminated polydimethylsiloxane, 1,3,5,7‐tetramethyl‐1,3,5,7‐tetravinyltetracyclosiloxane ( ), hydrogen‐terminated polydimethylsiloxane, and dimethylhydrogenmethyl oligomeric siloxane copolymer. The results of release performances using ascorbic acid as a model drug showed a cumulative linear slope over a week, indicating a constant release performance. Our data suggest that this siloxane TDDS could be useful for constant drug release over a long period. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42154.     

Sodium Excess Ta‐Modified (K0.5Na0.5)NbO3 Ceramics Prepared by Reactive Template Grain Growth Method

Lead‐free sodium excess Ta‐modified (K_0.470Na_0.545)(Nb_0.55Ta_0.45)O₃ (KNNT) ceramics were synthesized by a conventional and reactive templated grain growth methods, and their degree of grain orientation, microstructure, dielectric, ferroelectric, and field‐induced strain properties were systematically investigated. A high degree of grain orientation (Lotgering factor F = 80%) was obtained in textured KNNT ceramics. Results showed that textured KNNT ceramics exhibit high grain orientation, dielectric constant, and field‐induced strain as compared to nontextured samples of the same composition. Room temperature unipolar field‐induced strain of K_0.5Na_0.5NbO₃ (KNN) ceramics was enhanced from 0.080% for nontextured sample to 0.115% for textured sample, and their corresponding dynamic piezoelectric coefficients () were improved from 320 pm/V to 460 pm/V, respectively.     

Characterization of molecular interaionic and intraionic crosslinkable sulfonated poly(ether ether ketone‐alt‐benzimidazole) membrane

Lysozyme-loaded polymeric composite microparticles were successfully coprecipitated by solution-enhanced dispersion by supercritical CO₂ (SEDS), starting with a homogeneous organic solvent solution of lysozyme/poly(L -lactide)/poly(ethylene glycol) (lysozyme/PLLA/PEG). The effects of different drug loads (5, 8, and 12% w/w), PLLA Mw (10, 50, 100, and 200 kDa), PEG contents (0, 10, 30, and 50% PEG/(PLLA+PEG) w/w), and PEG Mw (400, 1000, and 4000 kDa) on the surface morphology, particle size, and drug release profile of the resulting composite microparticles were investigated. The results indicate that the size of the microparticles decreased and the rate of drug release increased with an increase in drug load, PEG content, or PEG Mw; the particle size first increased and then decreased with an increase in PLLA Mw, and the drug release was controlled by both particle size and PLLA Mw. The Fourier transform infrared spectrometer analysis and circular dichroism spectra measurement reveal that no significant changes occurred in the molecular structures during the SEDS processing, which is favorable to the production of protein–polymer composite microparticles for a protein drug delivery system. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Extracellular Matrix Biomarkers in Colorectal Cancer

The cellular microenvironment composition and changes therein play an extremely important role in cancer development. Changes in the extracellular matrix (ECM), which constitutes a majority of the tumor stroma, significantly contribute to the development of the tumor microenvironment. These alterations within the ECM and formation of the tumor microenvironment ultimately lead to tumor development, invasion, and metastasis. The ECM is composed of various molecules such as collagen, elastin, laminin, fibronectin, and the MMPs that cleave these protein fibers and play a central role in tissue remodeling. When healthy cells undergo an insult like DNA damage and become cancerous, if the ECM does not support these neoplastic cells, further development, invasion, and metastasis fail to occur. Therefore, ECM-related cancer research is indispensable, and ECM components can be useful biomarkers as well as therapeutic targets. Colorectal cancer specifically, is also affected by the ECM and many studies have been conducted to unravel the complex association between the two. Here we summarize the importance of several ECM components in colorectal cancer as well as their potential roles as biomarkers.     

Regeneration of H<Subscript>3</Subscript>PW<Subscript>12</Subscript>O<Subscript>40</Subscript> catalyst in the direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas

Methods for regenerating H₃PW₁₂O₄₀ catalyst in the solvent-free direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas were investigated. Regenerated H₃PW₁₂O₄₀ catalyst was then applied to the solvent-free direct preparation of DCP. In the solvent-free direct preparation of DCP, selectivity for DCP over H₃PW₁₂O₄₀ catalyst regenerated by method I (recovery of solid H₃PW₁₂O₄₀ catalyst by evaporating homogeneous liquidphase product solution) significantly decreased with increasing recycling run, while that over H₃PW₁₂O₄₀ catalyst regenerated by method II (regeneration of H₃PW₁₂O₄₀ catalyst by oxidative calcination of solid product recovered by method I) was slightly decreased with no significant catalyst deactivation with respect to recycling run. On the other hand, selectivity for DCP over H₃PW₁₂O₄₀ catalyst regenerated by method III (regeneration of H₃PW₁₂O₄₀ catalyst by recrystallization and subsequent oxidative calcination of solid product recovered by method II) was the same as that over fresh catalyst without any catalyst deactivation with respect to recycling run. Thus, method III was found to be the most efficient method for the regeneration of H₃PW₁₂O₄₀ catalyst.     

Preparation and properties of montmorillonite‐based polyimide nanocomposites

Montmorillonite (MMT)‐based polyimide (PI) nanocomposites were prepared via two‐stage polymerization of PI using polyamic acid (PAA). The clay was organically modified using various alkylammonium ions to examine the effect of changes in alkyl length on the intercalation spacing of both the treated clays and their hybrids with PAA and PI. The intercalation behavior of clay in the PI matrix and its thermal and mechanical properties were investigated as a function of clay concentration. The d‐spacing of organically modified MMT (O‐MMT) increased with increasing length of the alkylammonium chain. PI/O‐MMT hybrids form exfoliated nanocomposites at clay concentrations below 2 wt%, while they form intercalated nanocomposites together with some exfoliated ones at clay contents exceeding 4 wt%. Young's modulus increased rapidly to a clay loading of 2 wt%, and leveled off with further increases in clay loading. The tensile strength at break increased rapidly up to a clay loading of 1 wt%, and then decreased sharply, while the strain at break showed a monotonic decrease with increasing clay loading from 0 to 8 wt%. The storage modulus, E′, in the temperature range below the glass transition temperature T_g, generally increased with increasing clay content, except at the highest clay content of 8 wt%. Copyright © 2004 Society of Chemical Industry     

Surface reaction of LiCoO2/Li system under high-voltage conditions by X-ray spectroscopy and two-dimensional correlation spectroscopy (2D-COS)

We studied the surface reactions of a LiCoO(2)/Li cell under high-voltage conditions using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and two-dimensional correlation spectroscopy (2D-COS). 2D XPS correlation spectra show that Li(2)CO(3) is formed first by decomposition of the organic solvents, and then polycarbonate, which is formed by polymerization of the electrolytes, is produced on the cathode surface of the LiCoO(2)/Li system under high-voltage conditions. XAS measurements also confirm that the solid electrolyte interface (SEI) layer is formed on the LiCoO(2) electrode by decomposition of the organic solvents. The thickness of the SEI layer is less than 100 ?.     

生物植入用碳纳米管增强混合功能梯度材料的力学性能(英文)

利用羟基磷灰石(HA)、不锈钢316L(SS316L)和碳纳米管(CNT)制备生物医学植入体用混合功能梯度材料(FGM)。加入SS316L和CNT增强功能梯度材料离散层的HA制成三种不同类型的功能梯度材料。第一种功能梯度材料加入10%~40%(质量分数)的SS316L强化微米HA,浓度梯度为10%。第二种功能梯度材料,在第一种功能梯度材料的基础上加入0.5%(质量分数)的功能化碳纳米管。第三种功能梯度材料在第二种功能梯度材料的基础上加入微米HA和纳米HA(1:1)的混合物。所有类型的功能梯度材料在相似的压缩参数和烧结参数下,进行单轴压缩实验,并采用无压烧结技术进行烧结。结果表明,加入碳纳米管和纳米晶体HA提高了功能梯度材料的致密度。碳纳米管增强的功能梯度材料的硬度和断裂韧性增加,但是微米和纳米晶体HA增强的功能梯度材料的硬度和断裂韧性的增加更明显。     

Quantitative classification of DNA damages induced by submicromolar cadmium using oligonucleotide chip coupled with lesion-specific endonuclease digestion

Implementation of proper analytical tool for systematic investigation and quantitative determination of different classes of cadmium ion-induced DNA damages, especially at low metal ion concentrations, is still lacking. Using lesion-specific enzymes that cleave DNA at specific classes of damage and a fluorometric approach developed for quantifying fluorophore-labeled oligonucleotides bound to chip surfaces, we determined the frequencies of different lesions (strand breaks, oxidized purines, oxidized pyrimidines, or abasic sites) induced by submicromolar Cd(2+). Cd(2+)-treated oligonucleotide chips were digested with various endonucleases (Fpg protein, endonuclease III, endonuclease IV), producing a de novo single strand break (SSB) at their substrate modifications. The frequency of SSB and double strand break (DSB) was computed from the difference of pre- and post-Cd(2+)-treatment oligonucleotide coverage on the chip. While the frequency of SSBs and oxidized bases were successfully quantified even at 0.5 μM of Cd(2+), DSB frequency could be easily quantitated at 8.7 μM [Cd(2+)]. The numbers of abasic sites were below the oligonucleotide detection limit (2.4 amole; equivalent to 0.24 fM for a reaction volume of 100 μL). SSBs were found to constitute about 85-90% of single strand damages, while oxidized bases comprise only 4-7% of the total at 0.9 to 8.7 μM [Cd(2+)].     

Density of States-Based DC $I$– $V$ Model of Amorphous Gallium–Indium–Zinc-Oxide Thin-Film Transistors

The density of states (DOS)-based DC I-V model of an amorphous gallium-indium-zinc oxide (a-GIZO) thin-film transistor (TFT) is proposed and demonstrated with self-consistent methodologies for extracting parameters. By combining the optical charge-pumping technique and the nonlinear relation between the surface potential (phiS) and gate voltage (V _GS), it is verified that the proposed DC model reproduces well both the measured V _GS-dependent mobility and the I _DS-V _GS characteristics. Finally, the extracted DOS parameters are N _TA = 4.4 times 10¹⁷ cm^-3 middot eV^-1, N _DA = 3 times 10¹⁵ cm^-3 middot eV^-1, kT _TA = 0.023 eV, kT _DGA = 1.5 eV, and EO = 1.8 eV, with the formulas of exponential tail states and Gaussian deep states.