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The acid dissociation of a nitric acid HNO3molecule located at various depths in a water slab is investigated via Car−Parrinello molecular dynamics simulations. HNO3is found to remain molecular when it is adsorbed on top of the surface with two hydrogen-bonds, and to dissociatealthough not alwaysby transferring a proton to a water molecule within a few picoseconds when embedded at various depths within the aqueous layer. The acid dissociation events are analyzed and discussed in terms of the proton donor−acceptor O−O hydrogen bonding distance and the configurations of the nearest-neighbor solvent waters of an HNO3·H2O pair. Four key structural features for the HNO3acid dissociation are identified and employed to analyze the trajectory results. Key solvent motions for the dissociation include the decrease of the proton donor−acceptor O−O hydrogen bonding distance and a 4 to 3 coordination number change for the proton-accepting water. The Eigen cation (H3O+), rather than the Zundel cation (H5O2+), is found to be predominant next to the NO3−ion in contact ion pairs in all cases. [ABSTRACT FROM AUTHOR]

The infrared signatures of nitric acid HNO 3and its conjugate anion NO 3−at the surface of an aqueous layer are derived from electronic structure calculations at the HF/SBK+∗ level of theory on the HNO 3·(H 2O) 3→ NO 3−·H 3O +·(H 2O) 2model reaction system embedded in clusters comprising 33, 40, 45, and 50 classical, polarizable waters, mimicking various degrees of solvation [Bianco, R.; Wang, S.; Hynes, J. T. J. Phys. Chem. A2007, 111, 11033]. The molecular level character of the various bands is discussed, and the solvation patterns are described in terms of hydrogen bonding and resulting polarization of the species’ intramolecular bonds. Connection is made with assorted experimental results, including surface-sensitive Sum Frequency Generation spectroscopy of aqueous nitric acid solutions, infrared spectroscopy of amorphous thin films of nitric acid monohydrate (NAM) and dihydrate (NAD), and infrared and Raman spectroscopic results for bulk aqueous solutions of nitric acid and nitrate salts. [ABSTRACT FROM AUTHOR]

The issue of acid dissociation of nitric acid at an aqueous surface is relevant in various portions of the atmosphere in connection with ozone depletion. This proton-transfer reaction is studied here via electronic structure calculations at the HF/SBK(d) level of theory on the HNO3·(H2O)3model reaction system embedded in clusters comprising 33, 40, 45, and 50 classical, polarizable waters with an increasing degree of solvation of the nitrate group. Free energy estimates for all the cases examined favor undissociated, molecular nitric acid over the 0−300 K temperature range, including that relevant for the upper troposphere, where it is connected to the issue of the mechanism of nitric acid uptake by water ice aerosols. The presence of molecular HNO3at 300 K at the surface is further supported by vibrational band assignments in good agreement with a very recent surface-sensitive vibrational spectroscopy study of diluted HNO3/H2O solutions. [ABSTRACT FROM AUTHOR]

Purpose: The epidermal growth factor receptor (EGFR) autocrine pathway plays an important role in cancer cell growth. Vascular endothelial growth factor A (VEGF‐A) is a key regulator of tumor‐induced endothelial cell proliferation and vascular permeability. ZD6474 is an orally available, small molecule inhibitor of VEGF receptor‐2 (VEGFR‐2), EGFR and RET tyrosine kinase activity. We investigated the activity of ZD6474 in combination with cetuximab, an anti‐EGFR blocking monoclonal antibody, to determine the anti‐tumor activity of EGFR blockade through the combined use of two agents targeting the receptor at different molecular sites in cancer cells and of VEGFR‐2 blockade in endothelial cells. Experimental Design: The anti‐tumor activity in vitro and in vivo of ZD6474 and/or cetuximab was tested in human cancer cell lines with a functional EGFR autocrine pathway. Results: The combination of ZD6474 and cetuximab determined synergistic growth inhibition in all cancer cell lines tested as assessed by the Chou and Talalay method. In nude mice bearing established human colon carcinoma (GEO) or lung adenocarcinoma (A549) xenografts and treated with ZD6474 and/or cetuximab for 4 weeks, a reversible tumor growth inhibition was caused by each drug. In contrast, a more significant tumor growth delay resulted from the combination of the two agents with an approximately 100–110 days increase in mice median overall survival as compared to single agent treatment. Conclusions: This study provides a rationale for evaluating in a clinical setting the double blockade of EGFR in combination with inhibition of VEGFR‐2 signaling as cancer therapy. J. Cell. Physiol. 208: 344–353, 2006. © 2006 Wiley‐Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose To test the efficacy of adding cisplatin to first-line treatment for elderly patients with advanced non-small-cell lung cancer (NSCLC) within a combined analysis of two parallel phase III trials, MILES-3 and MILES-4. Patients and Methods Patients with advanced NSCLC who were older than age 70 years with Eastern Cooperative Oncology Group performance status 0 to 1 were randomly assigned to gemcitabine or pemetrexed, without or with cisplatin. In each trial, 382 events were required to detect a hazard ratio (HR) of death of 0.75, with 80% power and two-tailed α of .05. Trials were closed prematurely because of slow accrual, but the joint database allowed us to analyze the efficacy of cisplatin on the basis of intention-to-treat and adjusted by trial, histotype, non-platinum companion drug, stage, performance status, sex, age, and size of the study center. Results From March 2011 to August 2016, 531 patients (MILES-3, 299; MILES-4, 232) were assigned to gemcitabine or pemetrexed without (n = 268) or with cisplatin (n = 263). Median age was 75 years, 79% were male, and 70% had nonsquamous histology. At a median 2-year follow-up, 384 deaths and 448 progression-free survival events were recorded. Overall survival was not significantly prolonged with cisplatin (HR, 0.86; 95% CI, 0.70 to 1.05; P = .14) and global health status score of quality of life was not improved, whereas progression-free survival (HR, 0.76; 95% CI, 0.63 to 0.92; P = .005) and objective response rate (15.5% v 8.5%; P = .02) were significantly better. Significantly more severe hematologic toxicity, fatigue, and anorexia were found with cisplatin. Conclusion The addition of cisplatin to single-agent chemotherapy does not significantly prolong overall survival, and it does not improve global health status score of quality of life in elderly patients with advanced NSCLC.