Synthesis and spectroscopic properties of furyl-phenyl-acrylates and naphthofurans and their interaction with ct- DNA

A series of novel substituted derivatives related to furyl-phenyl-acrylates and naphthofurans, was synthesized and characterized by UV/Vis and fluorescence spectroscopy. Acyclic compounds can undergo photochemical dehydrocyclization by visible light irradiation in order to obtain their cyclic derivatives. The interactions of the prepared compounds with calf thymus DNA was investigated by means of electronic absorption and fluorescence spectra. It is intriguing that addition of ct-DNA induced a fluorescence increase of acyclic derivatives, exactly the opposite of the strong fluorescence quenching observed for cyclic derivatives 10 and 12. Compound 11 showed decreasing fluorescence intensity for lower concentrations of ct-DNA, while increasing of fluorescence is observed for high excess of added ct-DNA.     

Synthesis of a small library of non-symmetric cyclic sulfamide HIV-1 protease inhibitors

A set of 11 non-symmetric cyclic sulfamide HIV-1 protease inhibitors were synthesized and evaluated. The use of a key microwave-assisted silver(I) oxide mediated selective mono N-benzylation reaction enabled fast and straightforward synthesis. The K_i values of the new inhibitors ranged between 0.28 μM and >20 μM.     

Linear Balanceable and Subcubic Balanceable Graphs*

In Math Program 55(1992), 129–168, Conforti and Rao conjectured that every balanced bipartite graph contains an edge that is not the unique chord of a cycle. We prove this conjecture for balanced bipartite graphs that do not contain a cycle of length 4 (also known as linear balanced bipartite graphs), and for balanced bipartite graphs whose maximum degree is at most 3. We in fact obtain results for more general classes, namely linear balanceable and subcubic balanceable graphs. Additionally, we prove that cubic balanced graphs contain a pair of twins, a result that was conjectured by Morris, Spiga, and Webb in ( Discrete Math 310(2010), 3228–3235).     

A High‐Quality Professional Development for Teachers of Grades 3–6 for Implementing Engineering into Classrooms

With the increasing emphasis on integrating engineering into K‐12 classrooms to help meet the needs of our complex and multidisciplinary society, there is an urgent need to investigate teachers' engineering‐focused professional development experiences as they relate to teacher learning, implementation, and student achievement. This study addresses this need by examining the effects of a professional development program focused on engineering integration, and how teachers chose to implement engineering in their classrooms as a result of the professional development. 198 teachers in grades 3–6 from 43 schools in 17 districts participated in a yearlong professional development program designed to help integrate the new state science standards, with a focus on engineering, into their teaching. Posters including lesson plans and student artifacts were used to assess teachers' engineering practices and the implementation in their classrooms. Results indicated that the majority of the teachers who participated in the professional development were able to effectively implement engineering design lessons in their classrooms suggesting that the teachers' success in implementing engineering lessons in their classroom was closely related to the structure of the professional development program.     

Asset portfolio securitizations and cyclicality of regulatory capital

This paper analyzes the level and cyclicality of regulatory bank capital for asset portfolio securitizations in relation to the cyclicality of capital requirements for the underlying loan portfolio as under Basel II/III. We find that the cyclicality of capital requirements is higher for (i) asset portfolio securitizations relative to primary loan portfolios, (ii) Ratings Based Approach (RBA) relative to the Supervisory Formula Approach, (iii) given the RBA for a point-in-time rating methodology relative to a rate-and-forget rating methodology, and (iv) under the passive reinvestment rule relative to alternative rules. Capital requirements of the individual tranches reveal that the volatility of aggregated capital charges for the securitized portfolio is triggered by the most senior tranches. This is due to the fact that senior tranches are more sensitive to the macroeconomy. An empirical analysis provides evidence that current credit ratings are time-constant and that economic losses for securitizations have exceeded the required capital in the recent financial crisis.