The authors indicated no potential conflicts of interest. REFERENCES 1. Bordignon KC, Neto MC, Ramina R, et al: Patterns of neuroaxis dissemination of gliomas: Suggestion of a classification based on magnetic resonance imaging findings. Surg Neurol 65:472-477, 2006; discussion 65:477, 2006 2. Engelhard HH, Corsten LA: Leptomeningeal metastasis of primary central nervous system (CNS) neoplasms. Cancer Treat Res 125:71-85, 2005 3. Gururangan S, McLaughlin CA, Brashears J, et al: Incidence and patterns of neuraxis metastases in children with diffuse pontine glioma. J Neurooncol 77:207-212, 2006 4. Stupp R, Mason WP, van den Bent MJ, et al: Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med 352:987-996, 2005 5. Wen PY, Kesari S, Drappatz J: Malignant gliomas: Strategies to increase the effectiveness of targeted molecular treatment. Expert Rev Anticancer Ther 6:733-754, 2006 6. Jackman DM, Holmes AJ, Lindeman N, et al: Response and resistance in a non-small-cell lung cancer patient with an epidermal growth factor receptor mutation and leptomeningeal metastases treated with high-dose gefitinib.

Poly(l-glutamines) with pyrene groups in the side chains (PPyMLGln) having different degrees of polymerization, i.e., DP 700, 360, and 70, and those with 45 and 25 mol % in pyrene content (PPy(45)MLGln (DP 360) and PPy(25)MLGln (DP 360)) were prepared, and their side-chain chromophore orientation was examined in solution and in film. In DMAc, these polymers, except PPy(25)MLGln, showed circular dichroism (CD) indicative of exciton coupling among the pyrene chromophores, suggesting that despite the long side chains the pyrene chromophores are oriented with respect to the main chain and with respect to one another owing to the rigid side-chain amide linkage and the bulkiness of the pyrene chromophores. In film, PPyMLGln (DP 700) showed CD signals remarkably different from those of the other polymers, suggesting that intermolecular interactions lead to a change in side-chain as well as main-chain conformation and thus to a change in chromophore orientation. Molecular mechanics calculations gave two regulated conformations with theoretical CD in accord with those observed with PPyMLGln (DP 700) in solution and in film, respectively. In DMAc, these polymers gave excimer emission whose intensity decreased with decreasing DP and decreasing pyrene content. Diminished excimer emission and rather strong exciton coupling found with PPy(45)MLGln suggest that many of its pyrene groups are situated in proximity and orientation, allowing exciton interaction but not allowing excimeric interaction.

The solubilities of a series of symmetrical tetraalkylammonium salts, R4NX (R=CH3–n-C8H17, including i-C4H9 and i-C5H11; X=Cl, Br, I, NO3, and ClO4), in water have been determined over the temperature range between 5 and 45 °C. The solubilities of these salts were found to be strongly dependent upon both the chain length of R of the R4N+ cation and upon the partial molar volume of the X− anion. It has been concluded that these solubilities are closely related with the stability of a “cage-like” water structure, which is presumably formed around the R4N+ cation in the solution. A thermodynamic interpretation of the solubility of the R4NX salts was made by using some thermodynamic properties obtained by a differential scanning calorimetry, together with the enthalpy of the solution calculated from the temperature dependence of the solubility.

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The nitinol stent was effective in treating malignant or benign tracheobronchial stenosis, and had some remarkable advantages compared with other tracheobronchial stents. In stenting, most procedures can be performed using flexible bronchoscope under local anesthesia.