Current recommendations for achieving high-quality professional development for teachers include the creation of a professional learning community. Key to the success of this approach, however, is the role of the peer mentor or coach. This study examined the experiences and perceptions of 31 professional development coaches in order to highlight the characteristics believed to be essential for success. Results suggest that, while content expertise is perceived to be important, coaches believe that strong interpersonal skills are more critical since, without them, they are unable to use their content knowledge to facilitate changes in teachers’ practice. Suggestions for selecting and training peer coaches are included.
Oligodeoxyribonucleotides with site-specific modifications have been used as substrates for Escherichia coli DNA polymerase I holoenzyme and Klenow fragment. Modificationis included the bulky guanine-8-aminoflqorene adduct and a guanine oxidation product resembling the product of photosensitized 1)NA oxidation. By a combination of primers and "nick-mers" conditions of single-strand-directed DNA synthesis and nick-translation could be created. Our results show that the polymerase can bypass both types of lesions. Bypass occurs on a single-stranded template but is facilitated on a nicked, double-stranded template. Only purines, with guanine more favored than adenine, are incorporated across both lesions. Hesitation during bypass coild not be detected. The results indicate that site-specifically modified oligonucleotides can be sensitive probes for the action of polymerases on damaged templates. They also suggest a function for polymerase I, in its nick-translation capacity, during DNA repair and mutagenesis.Mutation induced by gene damage is partially caused by the cell's polymerases. It is known that in Escherichia coli this involves a damage-induced or SOS response of great complexity, which allows the cell to overcome otherwise lethal damage at the expense of increased mutations (1, 2). Mutants of E. coli (umuC mutants) have been isolated in which error-prone repair is specifically affected (3). It has been suggested that the umuC gene product, part of the damageinduced response, is involved in a process of DNA replication that is inducible and able to synthesize DNA on a damaged template (4). This process might involve a temporary alteration of polymerase III (5). Another enzyme that appears to be involved in the damage-induced response is polymerase 1 (6). This enzyme is not inducible, but its suggested role in gap-filling, following excision repair and during postreplication repair, would imply that its nicked and gapped substrates would be available mostly under conditions of the induced SOS response.To improve our understanding of how polymerases respond to damaged templates, site-specifically modified oligonucleotides, in which a known position is substituted by a defined bulky carcinogen adduct, have been developed in this laboratory (7). Here we describe experiments designed to probe both the ability of polymerase I to replicate past a site-specifically modified template and the identity of the nucleotides inserted across from the modified base.
MATERIALS AND METHODSSynthesis of Operators with Site-Specific Modifications. The synthesis of a 14-mer operator fragment modified with 8-aminofluorene has been described (7). For the present study, we have synthesized 17-mer, 18-mer, and 23-mer operator strands. The conventional identification of the transcribed strand as the top strand is used (8). Sequences 3' and 5' of the central 17-mer operator are restriction sites. Both the adoption of the phosphoramidite chemistry (9) and the purification by tritylselection (10) gave a much cleaner product as ju...
Computer simulation tools are frequently used in engineering design work, and undergraduates are often trained to use these tools as they learn to design systems. The use of new tools in the learning environment should be evaluated to assure that the students are able to use the tools effectively. This study details and demonstrates the use of a Kirkpatrick's Level 1 Evaluation to assess the effectiveness of an instructional environment in which students learn to use a computer simulation tool to perform engineering design work. Specifically, an evaluation was conducted to look at student perceptions of FOODS-LIB-a steady-state food process design tool, its user's manual learning modules, and the implementation of FOODS-LIB in a senior level design course. This evaluation was triangulated with an instructor's assessment of student products generated as the students used the learning modules and designed an ice cream manufacturing process using FOODS-LIB.
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