Engaging texts: Effects of concreteness on comprehensibility, interest, and recall in four text types.

Concreteness was investigated as a text feature that engaged readers' comprehension, interest, and learning in 4 text types: persuasion, exposition, literary stories, and narratives. Three concrete and 3 abstract texts were selected in each text type. Concrete and abstract titles served as recall cues and to investigate title concreteness effects. In 2 experiments, undergraduates read the texts and either provided written recalls or rated them for familiarity, concreteness, interestingness, and comprehensibility. Concrete texts were recalled better than abstract texts, although the magnitude of the advantage varied across text types. Concreteness was overwhelmingly the best predictor of overall comprehensibility, interest, and recall. Effects of title concreteness varied across text types. Results extend the findings of M. Sadoski, E. T. Goetz, and J. B. Fritz (see records 1993-36182-001 and 1993-32227-001) and are consistent with dual coding theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preoperative radiation, surgical margins, and local control of extremity sarcomas of soft tissues

The relationship between status of the surgical margin and local control of soft tissue sarcoma of the extremities by preoperative radiation therapy has been assessed in 132 consecutive patients from 1974 to 1988. The 5-year actuarial local control rate was 94% for all patients; the rates were 97% and 82% for the 104 tumors with negative margins and the 28 tumors with positive margins, respectively. The local control rate was independent of the extent of the negative margin. For primary sarcomas, the local control rates were 96%, 97%, and 100%, respectively, for margins that were negative at < or = 1 mm or > 1 mm, or the specimens were negative for tumor; for positive margins the result was 83%. The overall local control rate was lower (not significant) for recurrent than for primary sarcomas: 88% vs. 94%. On the other hand, when stratifying by margin status, no difference was observed in local control results, i.e.: (1) 97% and 91% for primary and recurrent tumors with negative margins, respectively, and (2) 83% and 80% for primary and recurrent tumors with positive margins, respectively. Local control was not significantly higher in those patients who were treated by surgical resection (S), radiation (RT), and re-excision of the previous tumor bed than in those whose radiation therapy was started after the biopsy and followed by one surgical resection. For primary sarcomas that were resected with negative margins the results were: 100% of 15 patients treated by S-RT-S and 96% of 75 patients treated by RT-S.     

Concreteness and imagery effects in the written composition of definitions.

In 2 experiments, undergraduates composed written definitions of concrete and abstract nouns that were matched for frequency of usage and meaningfulness. Across both experiments, definitions of concrete words exhibited higher ratings for quality, greater length in words, shorter latencies, and more self-reports of an imagery strategy. Definitions for abstract words produced more self-reports of a verbal-associative strategy. The results replicate those of an earlier study involving oral production of definitions, suggesting that common cognitive mechanisms underlie the production of spoken and written language as explained by dual coding theory. Instructionally, the use of concreteness and imagination in composing definitions may lead to improved student writing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of concreteness on comprehensibility, interest, and memory for text: Implications for dual coding theory and text design.

The comprehensibility, interestingness, familiarity, and memorability of concrete and abstract instructional text were investigated in 4 experiments. Exp 1 investigated relationships between ratings of concreteness, familiarity, interestingness, and comprehensibility in concrete and abstract sentences about historical figures. Exp 2 investigated the immediate and delayed recall of those sentences, and employed rating norms from Exp 1 as predictors of recall. Exps 3 and 4 replicated aspects of Exps 1 and 2 with paragraphs of varying length. Results indicated that concreteness (ease of imagery) was the variable overwhelmingly most related to comprehensibility and recall. Discussion evaluates dual coding theory vs schema theory in explaining the results, suggests guidelines for text design, and offers a new perspective on the "seductive details" phenomenon, suggesting that abstractions also pose problems for learners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single electron reduction of cytochrome c oxidase compound F: resolution of partial steps by transient spectroscopy

The final step of the catalytic cycle of cytochrome oxidase, the reduction of oxyferryl heme a3 in compound F, was investigated using a binuclear polypyridine ruthenium complex (Ru2C) as a photoactive reducing agent. The net charge of +4 on Ru2C allows it to bind electrostatically near CuA in subunit II of cytochrome oxidase. Photoexcitation of Ru2C with a laser flash results in formation of a metal-to-ligand charge-transfer excited state, Ru2C, which rapidly transfers an electron to CuA of cytochrome oxidase from either beef heart or Rhodobacter sphaeroides. This is followed by reversible electron transfer from CuA to heme a with forward and reverse rate constants of k1 = 9.3 x 10(4) s-1 and k-1 = 1.7 x 10(4) s-1 for R. sphaeroides cytochrome oxidase in the resting state. Compound F was prepared by treating the resting enzyme with excess hydrogen peroxide. The value of the rate constant k1 is the same in compound F where heme a3 is in the oxyferryl form as in the resting enzyme where heme a3 is ferric. Reduction of heme a in compound F is followed by electron transfer from heme a to oxyferryl heme a3 with a rate constant of 700 s-1, as indicated by transients at 605 and 580 nm. No delay between heme a reoxidation and oxyferryl heme a3 reduction is observed, showing that no electron-transfer intermediates, such as reduced CuB, accumulate in this process. The rate constant for electron transfer from heme a to oxyferryl heme a3 was measured in beef cytochrome oxidase from pH 7.0 to pH 9.5, and found to decrease upon titration of a group with a pKa of 9.0. The rate constant is slower in D2O than in H2O by a factor of 4.3, indicating that the electron-transfer reaction is rate-limited by a proton-transfer step. The pH dependence and deuterium isotope effect for reduction of isolated compound F are comparable to that observed during reaction of the reduced, CO-inhibited CcO with oxygen by the flow-flash technique. This result indicates that electron transfer from heme a to oxyferryl heme a3 is not controlled by conformational effects imposed by the initial redox state of the enzyme. The rate constant for electron transfer from heme a to oxyferryl heme a3 is the same in the R. sphaeroides K362M CcO mutant as in wild-type CcO, indicating that the K-channel is not involved in proton uptake during reduction of compound F.