Miami University

About: Miami University is a education organization based out in Oxford, Ohio, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 9949 authors who have published 19598 publications receiving 568410 citations. The organization is also known as: Miami of Ohio & Miami-Ohio.

Overexpression, Purification, and Characterization of the Cloned Metallo-β-Lactamase L1 from Stenotrophomonas maltophilia

Abstract: The metallo-beta-lactamase L1 from Stenotrophomonas maltophilia was cloned, overexpressed, and characterized by spectrometric and biochemical techniques. Results of metal analyses were consistent with the cloned enzyme having 2 mol of tightly bound Zn(II) per monomer. Gel filtration chromatography demonstrated that the cloned enzyme exists as a tightly held tetramer with a molecular mass of ca. 115 kDa, and matrix-assisted laser desorption ionization and time-of-flight mass spectrometry indicated a monomeric molecular mass of 28.8 kDa. Steady-state kinetic studies with a number of diverse penicillin and cephalosporin antibiotics demonstrated that L1 effectively hydrolyzes all tested compounds, with k(cat)/Km values ranging between 0.002 and 5.5 microM(-1) s(-1). These characteristics of the recombinant enzyme are contrasted to those previously reported for metallo-beta-lactamases isolated directly from S. maltophilia.

The geological, isotopic, botanical, invertebrate, and lower vertebrate surroundings of Ardipithecus ramidus.

Abstract: Sediments containing Ardipithecus ramidus were deposited 4.4 million years ago on an alluvial floodplain in Ethiopia’s western Afar rift. The Lower Aramis Member hominid-bearing unit, now exposed across a >9-kilometer structural arc, is sandwiched between two volcanic tuffs that have nearly identical 40Ar/39Ar ages. Geological data presented here, along with floral, invertebrate, and vertebrate paleontological and taphonomic evidence associated with the hominids, suggest that they occupied a wooded biotope over the western three-fourths of the paleotransect. Phytoliths and oxygen and carbon stable isotopes of pedogenic carbonates provide evidence of humid cool woodlands with a grassy substrate.

Urban african-american middle school science students : Does standards-based teaching make a difference?

Abstract: The current reform movement in science education promotes standards-based teaching, including the use of inquiry, problem solving, and open-ended questioning, to improve student achievement. This study examines the influence of standards-based teaching practices on the achievement of urban, African-American, middle school science students. Science classes of teachers who had participated in the professional development (n = 8) of Ohio's statewide systemic initiative (SSI) were matched with classes of teachers (n = 10) who had not participated. Data were gathered using group-administered questionnaires and achievement tests that were specifically designed for Ohio's SSI. Analyses indicate that teachers who frequently used standards-based teaching practices positively influenced urban, African-American students' science achievement and attitudes, especially for boys. Additionally, teachers' involvement in the SSI's professional development was positively related to the reported use of standards-based teaching practices in the classroom. The findings support the efficacy of high-quality professional development to change teaching practices and to enhance student learning. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 1019–1041, 2000