In situ micro-sized gel-forming injectable implant using biodegradable amphiphilic graft copolymer

A synthesized graft polymer is used as a biodegradable polymer for an in situ gel-forming injectable implant system. The amphiphilic character of the polymer in the graft structure lowered the viscosity of the polymer solution, which enabled easy injection. A micro-sized gel can be obtained with this system, which has not been found for previous in situ gel-forming systems with poly[(D,L-lactide)-co-glycolide] copolymer. In addition, a protein particle embedded gel exhibits good in vitro drug release performance as a result of the enhanced stability and shorter diffusion length.     

Silica/Poly(1,5‐dioxepan‐2‐one) Hybrid Nanoparticles by “Direct” Surface‐Initiated Polymerization

Summary: Biodegradable poly(1,5‐dioxepan‐2‐one) (PDXO) was grown directly from Si OH groups of a silica nanoparticle by surface‐initiated, ring‐opening polymerization (SI‐ROP) of 1,5‐dioxepan‐2‐one (DXO). The direct SI‐ROP of DXO was achieved by heating a mixture of Sn(Oct)₂, DXO, and the silica nanoparticles (316 nm in diameter) in anhydrous toluene. The resulting silica/PDXO hybrid nanoparticles were characterized by means of ¹H NMR spectroscopy, IR spectroscopy, thermogravimetric analysis, and field‐emission scanning electron microscopy.

The procedure for the surface‐initiated, ring‐opening polymerization of 1,5‐dioxepan‐2‐one on silica nanoparticles reported here.     

Synthesis and characterization of a series of wholly aromatic copolyesters containing 2‐(α‐phenylisopropyl)hydroquinone moiety

Two series of new wholly aromatic thermotropic copolyesters containing the 2‐(α‐phenylisopropyl)hydroquinone (PIHQ) moiety have been synthesized and their basic properties such as glass transition temperature (T_g), melting temperature (T_m), thermal stability, crystallinity, and liquid crystallinity were studied by differential scanning calorimetry (DSC), thermogravimetry (TG), and wide‐angle X‐ray diffractometry (WAXD) and on a polarizing microscope. The first series was prepared from acetylated PIHQ, terephthalic acid (TPA), and 2,6‐naphthalenedicarboxylic acid (NDA), and the second series from acetylated PIHQ, TPA, and 1,1′‐biphenyl‐4,4′‐dicarboxylic acid (BDA). The T_g values (152–168°C) of the two series are not much different, although the values for the first series appear slightly higher. The T_m values (287–378°C) and the degree of crystallinity of the first series are appreciably greater than those of the second series. Such differences can be explained by the geometric structure of NDA and BDA moieties. All of the present polyesters are thermotropic and nematic. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 881–889, 1999     

Modified gap states in Fe/MgO/SrTiO3 interfaces studied with scanning tunneling microscopy

The geometric and electronic structures of Fe islands on MgO film layers were studied with scanning tunneling microscopy and spectroscopy. The MgO layers were grown on a Nb-doped single crystal SrTiO₃ (100) surface. Deposited Fe atoms aggregate into islands, the height and diameter of which are about 2.5 and 9.4 nm respectively. Fe islands modify the electronic structure of MgO surface; a ring type depression in the scanning tunneling microscope topography appears by lowered local electron density of states around Fe islands. We find that adsorbed Fe atoms reduce the gap states of MgO layers around Fe islands, which is attributed to the reason for the depletion of the electronic density of states.     

High‐Quality Stereo Depth Map Generation Using Infrared Pattern Projection

In this paper, we present a method for obtaining a highquality 3D depth. The advantages of active pattern projection and passive stereo matching are combined and a system is established. A diffractive optical element (DOE) is developed to project the active pattern. Cross guidance (CG) and auto guidance (AG) are proposed to perform the passive stereo matching in a stereo image in which a DOE pattern is projected. When obtaining the image, the CG emits a DOE pattern periodically and consecutively receives the original and pattern images. In addition, stereo matching is performed using these images. The AG projects the DOE pattern continuously. It conducts cost aggregation, and the image is restored through the process of removing the pattern from the pattern image. The ground truth is generated to estimate the optimal parameter among various stereo matching algorithms. Using the ground truth, the optimal parameter is estimated and the cost computation and aggregation algorithm are selected. The depth is calculated and bad‐pixel errors make up 4.45% of the non‐occlusion area.     

Oligoether-strapped calix[4]pyrrole: an ion-pair receptor displaying cation-dependent chloride anion transport

A ditopic ion-pair receptor (1), which has tunable cation- and anion-binding sites, has been synthesized and characterized. Spectroscopic analyses provide support for the conclusion that receptor 1 binds fluoride and chloride anions strongly and forms stable 1:1 complexes ([1·F](-) and [1·Cl](-)) with appropriately chosen salts of these anions in acetonitrile. When the anion complexes of 1 were treated with alkali metal ions (Li(+), Na(+), K(+), Cs(+), as their perchlorate salts), ion-dependent interactions were observed that were found to depend on both the choice of added cation and the initially complexed anion. In the case of [1·F](-), no appreciable interaction with the K(+) ion was seen. On the other hand, when this complex was treated with Li(+) or Na(+) ions, decomplexation of the bound fluoride anion was observed. In contrast to what was seen with Li(+), Na(+), K(+), treating [1·F](-) with Cs(+) ions gave rise to a stable, host-separated ion-pair complex, [F·1·Cs], which contains the Cs(+) ion bound in the cup-like portion of the calix[4]pyrrole. Different complexation behavior was seen in the case of the chloride complex, [1·Cl](-). Here, no appreciable interaction was observed with Na(+) or K(+). In contrast, treating with Li(+) produces a tight ion-pair complex, [1·Li·Cl], in which the cation is bound to the crown moiety. In analogy to what was seen for [1·F](-), treatment of [1·Cl](-) with Cs(+) ions gives rise to a host-separated ion-pair complex, [Cl·1·Cs], in which the cation is bound to the cup of the calix[4]pyrrole. As inferred from liposomal model membrane transport studies, system 1 can act as an effective carrier for several chloride anion salts of Group 1 cations, operating through both symport (chloride+cation co-transport) and antiport (nitrate-for-chloride exchange) mechanisms. This transport behavior stands in contrast to what is seen for simple octamethylcalix[4]pyrrole, which acts as an effective carrier for cesium chloride but does not operates through a nitrate-for-chloride anion exchange mechanism.     

Determination and pharmacokinetics of [6]-gingerol in mouse plasma by liquid chromatography-tandem mass spectrometry

This study describes the development of a rapid and sensitive high‐performance liquid chromatography–electrospray ionization tandem mass spectrometry (LC‐MS/MS) assay for the quantification of [6]‐gingerol in mouse plasma and application to a pharmacokinetic study after dose ranging in mice. The assay involved a protein precipitation step with acetonitrile and an isocratic elution using a mobile phase consisting of acetonitrile and water containing 0.1% formic acid (80:20 v/v). The multiple reaction monitoring was based on the transition of m/z = 277.2 → 177.1 for [6]‐gingerol and 294.2 → 137.1 for nonivamide (internal standard). The assay was validated to demonstrate the specificity, linearity, recovery, accuracy, precision and stability. The calibration curves were linear over the wide concentration range of 10–10,000 ng/mL (r ≥ 0.9988). The lower limit of quantification was 10 ng/mL using a small volume of mouse plasma (20 μL). The method was successfully applied to a pharmacokinetic study in mice after intravenous injection of [6]‐gingerol at 1.5, 3 and 6 mg/kg doses. The pharmacokinetics of [6]‐gingerol were linear over the dose range studied as demonstrated by the linear increase in area under the concentration‐time curve (AUC_inf) with no significant change in the systemic clearance (Cl_s), volume of distribution (V_ss) and elimination half‐life (t_1/2) as a function of dose. Copyright © 2011 John Wiley & Sons, Ltd.     

A calix[2]phenol[2]pyrrole and a fused pyrrolidine-containing derivative

The hybrid calix[2]phenol[2]pyrrole 4 and the fused pyrrolidine-containing macrocycle 9 were synthesized from two different isomeric starting materials, namely dimethyl 2-hydroxyisophthalate and 5-hydroxyisophthalate, respectively. The fused species 9 is devoid of obvious substrate binding properties. In contrast, the heterocalix system 4 displays the fluoride-induced conformational changes characteristic of the parent system.     

Spectroscopic identification of benzyl-type radicals generated by corona discharge of 2-chloro-4-fluorotoluene

By means of a technique of corona excited supersonic expansion coupled with a pinhole-type glass nozzle, we generated vibronically excited but jet-cooled benzyl-type radicals from precursor 2-chloro-4-fluorotoluene seeded in a large amount of inert carrier gas He. From an analysis of the visible vibronic emission spectrum, we found evidence of the formation of the 2-chloro-4-fluorobenzyl and 4-fluorobenzyl radicals. A possible pathway for the formation of these benzyl-type radicals is herein proposed. Also, the electronic energy in the D(1) → D(0) transition and the vibrational mode frequencies of the 2-chloro-4-fluorobenzyl radical in the ground electronic state were accurately determined, for the first time, by comparison with ab initio calculations and the known vibrational data of the precursor.