Manukyan A.K.,CUNY Hostos Community College
Theoretical Chemistry Accounts | Year: 2015
CHARMM force field parameters were developed for cyclopentane-modified peptide nucleic acid (cpPNA) analogs. As in the original force field parameterization, a self-consistent step-wise optimization approach was taken that involved the iterative adjustments of internal and external parameters until convergence was obtained. The geometry parameters such as standard bond lengths and bond angles were obtained by reproducing ab initio gas-phase geometries of model compounds. The internal force constants used for stretch and bend deformations were optimized to fit the calculated vibrational spectra. Torsional parameters were modified to fit the rotational barriers about single bonds in model compounds. The partial atomic charges were optimized based on interaction energies of complexes between water and the model compound. Our parameterization accurately reproduced high-level quantum mechanical calculations. The parameters were validated by series of molecular dynamics simulations of cpPNA in explicit water. Together with the existing force field for nucleic acids, these parameters will enable simulations of cpPNA complexes with RNA and DNA. © 2015, Springer-Verlag Berlin Heidelberg.
Koffi M.,CUNY Hostos Community College |
Andreopoulos Y.,City College of New York |
Jiji L.M.,City College of New York
Journal of Heat Transfer | Year: 2014
The oscillatory rotational motion of the elephant pinna is considered a key mechanism in metabolic heat dissipation. Limited experimental investigations have revealed that the flapping of the elephant's pinna is responsible for surface heat transfer enhancement. The objective of the present experimental and computational work is to investigate the physics of the flow induced by the pinna's motion and its effects on the heat transfer. This was accomplished by designing, fabricating and testing two full-size laboratory models of elephant pinnae: one rigid and one flexible, both instrumented with small size thermocouples for time-dependent surface temperature measurements. A constant heat flux is applied to both sides of each model which is rotated about a fixed edge with a frequency of 2 rad/s in an infinite domain at ambient conditions. Of interest is the study of the impact of the flexural strength of the model's material on surface heat transfer. Additional computer simulations of the flow and thermal fields revealed a hooked-shape vortex tube around the free edges of the flapping pinna. This result is confirmed by the flow visualization with smoke particles. Both experimental and computational results exhibit local surface temperature profiles characterized by a transient unsteady periodic variation followed by a steady periodic phase. Flow visualization indicated significant interaction between the vortical structures shed off the edge and the flexible model's boundary layer. It has been found that the cooling of the flexible model is enhanced by 30%. Copyright © 2014 by ASME.
Agency: NSF | Branch: Continuing grant | Program: | Phase: ADVANCED TECH EDUCATION PROG | Award Amount: 610.13K | Year: 2012
The Game-Framed Mathematics & Science (G-FMS) initiative supports existing digital media curricula at Eugenio María de Hostos Community College by reimagining how fundamental concepts in mathematics and science can be engaging to digital learners. Current remedial and college level mathematics and science curricula are being redesigned by framing the subjects within game design, providing a foundation for programming-centric courses and providing the skills for students to pursue careers in game design as well as interactive media. A collaborative group of professors from mathematics, physics, the natural sciences, design, and education are part of the team redesigning courses based on this game-framed pedagogy resulting in six new courses in mathematics, biology, environmental science, and physics.
Broader impacts include an implementation of the G-FMS curricula in a Summer Games Institute for secondary school students and through professional development workshops for college and secondary school educators interested in mirroring this pedagogical approach. Assessment goals are to improve scores on the COMPASS Mathematics placement exam, to increase student engagement in STEM courses, to increase student engagement with programming concepts, to create pathways from high schools to game design and STEM programs, and to provide student game design research opportunities. The evaluation plan utilizes surveys, interviews, and tools for student reflection. Dissemination is accomplished through faculty workshops, a dedicated website, presentations at a variety of game education conferences, and peer-reviewed publications.
Agency: NSF | Branch: Standard Grant | Program: | Phase: ROBERT NOYCE SCHOLARSHIP PGM | Award Amount: 299.08K | Year: 2012
This capacity building project is a collaboration between a four year (Lehman college, CUNY) and a two year (CUNY Hostos Community College) college, with the community college as the lead institution. Other partners include the American Museum of Natural History and the Black Forest Consortium, a mountainous area 50 miles north of New York City maintained as a resource for research and student and teacher training by the institutions within the consortium. The project is designed to provide a clear pathway to STEM teacher certification from the community college to the four year school with an emphasis on providing chemistry and earth science teachers well prepared to serve students in high needs schools. The partners are: (a) aligning the curricula of Hostos STEM courses and programs of study with those required for Lehman chemistry and environmental science majors, with a minor in education, to create two joint-degree/dual-admission programs to enable students to attend Hostos and then transition seamlessly to Lehman to complete their bachelors degree; (b) leveraging existing partnerships with the American Museum of Natural History and the Black Rock Forest station to design summer internships and semester workshops to provide field experiences, teacher preparation, and other research opportunities introducing Hostos students to chemistry and environmental science; (c) creating a bridge program, incorporating an intensive screening process to identify the students most likely to succeed in a Noyce Scholarship program and offering extensive mentoring and advisement to ensure that the selected Hostos students successfully transition to Lehman; (d) devising an effective public relations and recruitment plan to inform potential students about SEED at Hostos, so that STEM majors are made aware of the opportunities for careers in education; (e) designing a set of activities to support teachers during their induction years and (f) working with an evaluator who will design and implement an evaluation plan that will measure the stated objectives and outcomes of Project SEED.