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The surface assembly of 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP) using silicon tetrachloride as a coupling agent was investigated using atomic force microscopy (AFM). Nanopatterned films of Si-OEP were prepared by protocols of colloidal lithography to evaluate the morphology, thickness, and molecular orientation for samples prepared on Si(111). The natural self-stacking of porphyrins can pose a challenge for molecular patterning. When making films on surfaces, porphyrins will self-associate to form co-planar configurations of random stacks of molecules. There is a tendency for the flat molecules to orient spontaneously in a side-on arrangement that is mediated by physisorption to the substrate as well as by π-π interactions between macrocycles to form a layered arrangement of packed molecules, analogous to a stack of coins. When silicon tetrachloride is introduced to the reaction vessel, the coupling between the surface and porphyrins is mediated through covalent Si-O bonding. For these studies, surface structures of Si-OEP were formed that are connected with a Si-O-Si motif to a silicon atom coordinated to the center of the porphyrin macrocycles. Protocols of colloidal lithography were used as a tool to prepare surface structures and films of Si-OEP to facilitate surface characterizations. Conceptually, by arranging the macrocycles of porphyrins with defined orientation, local AFM surface measurements can be enabled to help address mechanistic questions about how molecules self-assemble and bind to substrates.

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BACKGROUND: Medication errors are a common occurrence during the conduct of anesthesia (one in 133-450 [corrected] patients). Several factors contribute to medication errors in anesthesia, including experience of the anesthesia provider, severity of comorbidities, and type of procedure. The inexperience of anesthesia providers-in-training also leads to increased error rates. This prospective observational study repeats and extends previous work by Webster et al. and Llewellyn et al. examining the role of comorbidities, type of case, and level of provider experience on the incidence of medication errors. METHODS: After Institutional Review Board review and exemption from informed consent, medication error reporting forms were attached to every anesthetic record during a six-month period. All providers were asked to return the forms for every anesthetic, on a strictly voluntary and anonymous basis, and to record the occurrence of medication errors. If providers indicated that a medication error had occurred, additional details about the event were obtained anonymously. RESULTS: There were 8,777 (83%) responses obtained in a review of 10,574 case forms. A medication error was reported in 35 forms, with an additional 17 forms indicating a medication pre-error or near miss, resulting in 52 (0.49%) errors/pre-errors or a reported incidence of 1:203 anesthetics. Most case types were observed to have a statistically significant increase in reported medication errors. Reported errors by type of anesthesia provider were categorized into anesthesia provider-in-training group and the experienced provider group. The anesthesia provider-in-training group reported a twofold increase in the rate of errors, with the most frequently reported errors being incorrect dose and substitution. CONCLUSION: This study suggests that case type, American Society of Anesthesiologists' classification, and level of provider experience play a role on the rate of medication errors. The results of this study are in agreement with previously reported error rates.

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The current study examined the accuracy of the multiple-stimulus without replacement (MSWO) preference assessment for identifying preferred common classroom activities as reinforcers with children with behavioral disorders. The accuracy of predictions from the MSWO regarding high, medium, and low stimulus preference was tested by providing contingent access to activities for completing math problems within an independent seatwork format. Overall, there was an interaction effect between preference ranking (high, medium, or low) and number of problems completed. The results confirm and extend previous findings regarding the accuracy of predictions with the MSWO. The findings also reveal, however, some individual differences that may account for instances in which student behavior did not conform to predictions of stimulus preference assessments.

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