Electron-stimulated desorption of anions from thin films of linear and supercoiled DNA is investigated in the range 3-20 eV. Resonant structures are observed with maxima at 9.4+/-0.3, 9.2+/-0.3, and 9.2+/-0.3 eV, respectively, in the yield dependence of H-, O-, and OH- on the incident electron energy. Their formation is attributed to dissociative electron attachment.

TX AbstractPurpose-To compare dose-volume histograms (DVHs) for intensity-modulated proton therapy (IMPT) with intensity-modulated radiation therapy (IMRT) and passive scattering proton therapy (PSPT) for stage IIIB non-small cell lung cancer (NSCLC) and explore the possibility of individualized radical radiotherapy.Methods and Materials-DVHs for IMPT, PSPT, and IMRT designed to deliver IMRT at 60 to 63 Gy, PSPT at 74 Gy, and IMPT at the same doses and individualized radical radiotherapy in patients with extensive stage IIIB NSCLC (N = 10 for each approach) were compared. These patients were selected based on their extensive disease and considered to have no or borderline tolerance of IMRT at 60 to 63 Gy based on normal tissue dose-volume constraints (lung V20<35%, total mean lung dose <20 Gy; spinal cord dose, <45 Gy). The possibility of increasing the total tumor dose with IMPT for each patient without exceeding the dose-volume constraints (maximum tolerant dose, MTD) was also investigated.Results-Compared with IMRT, IMPT spared more lung, heart, spinal cord, and esophagus even with dose escalation from 63 Gy to 83.5 Gy, with a mean MTD of 74 Gy. Compared with PSPT, IMPT allowed further dose escalation from 74 Gy to mean MTD of while keeping all parameters of normal tissue sparing lower or similar. In addition, IMPT prevented lower target coverage in patients with complicated tumor anatomies. Conclusions: IMPT reduces the normal tissue dose and allows individualized radical radiotherapy for extensive stage IIIB NSCLC.

Glass transition temperature is a critical parameter for achieving favorable and thermally stable bulk heterojunction morphology as it determines the kinetics of molecular organization of polymeric semiconducting materials. This study presents a sensitive method of precisely determining the glass transition temperature (T g) of conjugated polymers and polymer–PCBM blends using dynamic mechanical thermal analysis (DMTA). The method presented here is very versatile in which polymer or polymer–molecule films are reinforced using a woven glass fiber and utilizes only 5–10 mg of the material. This makes the method superior to differential scanning calorimetry (DSC) for determining the thermal properties of conjugated polymers. The effects of PCBM loading, solvents, and additive on the T g of polymer–PCBM blends and on the miscibility of different phases are investigated using the novel DMTA method. For the P3HT:PC61BM system, two different thermal transitions were found corresponding to P3HT-rich and PCBM-rich phases when cast using CHCl3, while chlorobenzene was found to result in a single T g for the blend which was between those of the pure components, indicating greater miscibility when cast from chlorobenzene. On the other hand, miscibility of PCBM in TQ1 was found to be relatively low, and two thermal transitions were found for all TQ1:PCBM blends. The total PCBM content or the solvent used was found to have little influence on the resultant PCBM miscibility in TQ1. T g of a range of other polymers as measured using DMTA is also reported to prove the versatility of this technique.

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In intensity-modulated radiotherapy (IMRT), the quality of the treatment plan, which is highly dependent upon the treatment planner's level of experience, greatly affects the potential benefits of the radiotherapy (RT). Furthermore, the planning process is complicated and requires a great deal of iteration, and is often the most time-consuming aspect of the RT process. In this paper, we describe a methodology to automate the IMRT planning process in lung cancer cases, the goal being to improve the quality and consistency of treatment planning. This methodology (1) automatically sets beam angles based on a beam angle automation algorithm, (2) judiciously designs the planning structures, which were shown to be effective for all the lung cancer cases we studied, and (3) automatically adjusts the objectives of the objective function based on a parameter automation algorithm. We compared treatment plans created in this system (mdaccAutoPlan) based on the overall methodology with plans from a clinical trial of IMRT for lung cancer run at our institution. The 'autoplans' were consistently better, or no worse, than the plans produced by experienced medical dosimetrists in terms of tumor coverage and normal tissue sparing. We conclude that the mdaccAutoPlan system can potentially improve the quality and consistency of treatment planning for lung cancer.

The glass transition temperature (T g ) of polymers is an important parameter that determines the kinetics of molecular organization of polymeric chains. Understanding the T g of conjugated polymers is critical in achieving a thermally stable and optimum morphology in polymer:polymer or polymer:small molecule blends in organic electronics. In this study, we have used the woven glass-mesh-based method of dynamic mechanical thermal analysis (DMTA) to evaluate the T g of polymer semiconductors, which is generally not easy to detect using conventional techniques such as differential scanning calorimetry (DSC). More importantly, we establish the relationship between the thermal transitions and the molecular structure of polymer semiconductors. For conjugated polymers with rigid conjugated backbones and large alkyl side chains, we report the presence of separate thermal transitions corresponding to the polymer backbone as well as transitions related to side chains, with the latter being the most prominent. By systematically comparing polymer side chains, molecular weight, and backbone structure, the origin of the T g and a sub-T g transitions have been successfully correlated to the polymer structures. The antiplastization effect of additives has also been used to further prove the origin of the different transitions. Thermal transitions of a range of high performing polymers applied in organic photovoltaics, including TQ1, PTNT, PTB7, PTB7-Th, and N2200, have been systematically studied in this work. According to the measurements, some of these polymers have a very small amorphous part, changing the way the morphology should be described for these materials. We infer that the main phase in these polymers consists of hairy aggregates, with a few π-stacked rigid polymer chains forming the aggregates.

We report results on the desorption of OH- induced by 0-19 eV electrons incident on self-assembled monolayer films made of single and double DNA strands of different orientations with respect to a gold substrate. Such measurements make it possible to deduce the mechanism and site of OH- formation within a biomolecule as complex as DNA. This type of damage is attributed to dissociative electron attachment to the phosphate group of DNA, when it contains the counterion H+.

Besides, Fenton's reagent helped to not only remove total organic carbon (TOC), heavy metals (As, Cu and Pb) and total phosphorus (TP), but also inactivate bacteria and reduce wastewater toxicity. This work demonstrates that the integrated process combining SBR with Fenton's reagent could provide comprehensive treatment to swine wastewater. ª 2009 Elsevier Ltd. All rights reserved. IntroductionThe concern about the occurrence of antibiotics in the environment has been growing due to the potential evolution of antibiotic resistant bacteria. Antibiotics are widely used in concentrated animal feeding operations (CAFOs) around the world to treat the diseases and improve the growth rate of animals. In China, over 8000 tons of antibiotics are currently used as feed additives each year (Henan Animal Husbandry Bureau, 2009). Antibiotics are often added in the feed and water for animal feeding. However, the majority of antibiotics are excreted in feces and urine without adsorption and metabolism by animals (Sarmah et al., 2006). As a result, the potential environmental risks brought about by antibiotics are increasing along with the rapid advance of livestock industry. In fact, antibiotics have been frequently detected in the slurry and wastewater of CAFOs (Haller et al., 2002;Malintan and Mohd, 2006). Multiple classes of antibiotics with relatively high concentrations, commonly at >100 mg/L levels, were detected in swine waste storage lagoons in the United States (Campagnolo et al., 2002). In our previous work, eight antibiotics including four sulfonamides, three tetracyclines and one * Corresponding author. Tel.: þ86 10 62849632; fax: þ86 10 62923541. E-mail address: qiangz@rcees.ac.cn (Z. Qiang).A v a i l a b l e a t w w w . s c i e n c e d i r e c t . w a t e r r e s e a r c h 4 3 ( 2 0 0 9 ) 4 3 9 2 -4 4 0 2