Benzene oxide, the initial metabolite of the human carcinogen benzene, reacts with DNA producing 7-phenylguanine (7-PhG) and other products. We developed a highly sensitive liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry-parallel reaction monitoring method for the analysis of 7-PhG in DNA. Accuracy and precision of the method were established and the detection limit was about 8amol of 7-PhG injected on the column and less than 1 adduct per 10(9) nucleotides in DNA. 7-PhG was detected in calf thymus DNA reacted with 1μM to 10mM benzene oxide. The method was applied for the analysis of DNA isolated from bone marrow, lung, and liver of B6C3F1 mice treated by gavage with 50mg/kg benzene in corn oil 5 times weekly for 4weeks. 7-PhG was not detected in any of these DNA samples. The method was applied to DNA from mouse hepatocytes exposed to 100μM benzene oxide and human TK-6 lymphoblasts exposed to 100μM, 1, and 10mM benzene oxide. 7-PhG was only detected in TK-6 cell DNA from the 10mM exposure. The method was also applied to leukocyte DNA from 10 smokers and 10 nonsmokers. 7-PhG was detected in only one DNA sample, from a nonsmoker. The results of this study do not support the hypothesis that the benzene oxide-DNA adduct 7-PhG is involved in carcinogenesis by benzene.

Successful implementation of wearable electronics requires practical wearable energy storage systems that can meet certain power and energy metrics. However, flexible, stretchable, and truly textile-grade energy storing platforms have so...

Problem formulation is an important part of the design process that has been largely underexplored. Similarly, the relationship between how designers formulate problems and creative outcome is not well understood. To shed light on what the process of problem formulation can tell us about creativity in design, we use the problem map model — a flexible, domain-independent ontology for modeling the design formulation process — to analyze protocols from eight expert designers. In this paper, we discuss the effectiveness of using problem maps for coding design protocols and what the problem map model can tell us about the protocols of designers. In this exploratory study, we use the problem map model to code and analyze the problem formulation stage of the design process.

Aerial seeding can quickly cover large and physically inaccessible areas 1 to improve soil quality and scavenge residual nitrogen in agriculture 2 , for postfire reforestation 3-6 and wildland restoration 7,8 . However, it suffers from low germination rates due to the direct exposure of unburied seeds to harsh sunlight, wind, granivorous birds, and undesirable air humidity and temperature 1,9,10 . Inspired by Erodium seeds 11-14 , we design and fabricate self-drilling seed carriers, turning wood veneer into highly stiff (7.2 GPa when dry, and 1.2 GPa when wet) and hygromorphic bending or coiling actuators with an extremely large bending curvature (1854 m -1 ), 45 times larger than the literature values [15][16][17][18] . Our three-tailed carrier has an 80% drilling success rate on flat land after two triggering cycles due to the beneficial resting angle (25° -30°) of its tail anchoring, whereas the natural Erodium seed's success rate is 0%. Our carriers can carry payloads of different sizes and contents including biofertilizers and plant seeds as large as those of whitebark pine, which are 11 mm in length. We compare experiments with numerical simulation to elucidate the curvature transformation and actuation mechanisms to guide the design and optimization of the seed carriers. Our system will significantly improve the effectiveness of aerial seeding to relieve agricultural and environmental stresses, and has potential applications in energy harvesting, soft robotics and sustainable buildings.

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