Polyurethanes (PUs) were synthesized with polyols derived from castor oil and isophorone diisocyanate. The materials were evaluated for their mechanical properties using stress–strain curves, thermogravimetric analysis, differential scanning calorimetry, and contact angle analysis. The biological response of the materials was evaluated by determining their cell viability in vitro, antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa, and biological response in vivo of PUs by means of implanting them in Wistar rats. The cell proliferation on the materials was analyzed using mouse fibroblast L929, human fibroblast MRC-5, and adult human dermal fibroblast (HDFa) cells by the ISO 10993-5 method. The materials showed no toxic effects and promoted cell proliferation. Experiments performed in vivo for 30 days in mice showed that the materials neither affected the wound healing process nor caused adverse effects or severe injuries in the dorsal mid-cervical tissue or organs on histological evaluation. PUs synthesized can be used in biomedical devices.

Weed biotypes putatively resistant to acetolactate synthase (ALS)–inhibiting herbicides were reported by Iowa farmers from 1997 to 2001. Greenhouse studies confirmed cross-resistance to triazolopyrimidine sulfonanilide and sulfonylurea (SU) herbicides in giant ragweed from Scott County, IA (Werner Farm), which corresponded to resistance to susceptibility (R:S) GR50 (50% growth reduction) ratios of 21 and 28 to cloransulam and primisulfuron + prosulfuron, respectively. At the enzyme level, this represented a 49- and 20-fold I 50 (50% enzyme inhibition) increase. Cross-resistance to imidazolinone (IMI) and SU herbicides was also observed in common sunflower from Cherokee, IA. Compared with a susceptible biotype, the resistant common sunflower biotype demonstrated GR50 R:S ratios of 36 and 43 to imazethapyr and chlorimuron, respectively. Shattercane from Malvern, IA, was susceptible to nicosulfuron but was resistant to imazethapyr (GR50 R:S ratio = 29). The woolly cupgrass biotypes from Union County, IA (Pettit Farm and Travis Farm), were reportedly resistant but were identified susceptible to both IMI and SU herbicides. Using an in vivo ALS assay, extractable endogenous 2,3-diketone concentrations ranged from 25 to 71 nmol g−1 fresh weight for all species. Compared with susceptible biotypes, 2,3-diketone levels accumulated to at least twofold higher levels in treated resistant plants 120 h after herbicide application. Field history data suggested that resistance evolved independently in three environments where ALS-inhibiting herbicides represented an important component of the selection pressure.