We have calculated the binding energy of various nucleobases (guanine (G), adenine (A), thymine (T) and cytosine (C)) with (5,5) single-walled carbon nanotubes (SWNTs) using ab-initio HartreFock method (HF) together with force field calculations. The gas phase binding energies follow the sequence G > A > T > C. We show that main contribution to binding energy comes from van-der Wall (vdW) interaction between nanotube and nucleobases. We compare these results with the interaction of nucleobases with graphene. We show that the binding energy of bases with SWNTs is much lower than the graphene but the sequence remains same. When we include the effect of solvation energy (Poisson-Boltzman (PB) solver at HF level), the binding energy follow the sequence G > T > A > C >, which explains the experiment [16] that oligonucleotides made of thymine bases are more effective in dispersing the SWNT in aqueous solution as compared to poly (A) and poly (C). We also demonstrate experimentally that there is differential binding affinity of nucleobases with the single-walled carbon nanotubes (SWNTs) by directly measuring the binding strength using isothermal titration (micro) calorimetry. The binding sequence of the nucleobases varies as thymine (T) > adenine (A) > cytosine (C), in agreement with our calculation.

Differences in tutor evaluation by male and female students indicate necessity of adopting different strategies by tutors in a different sociocultural background. The results of the study have direct implications for faculty development.

The amino acid Pro is more rigid than other naturally occurring amino acids and, in proteins, lacks an amide hydrogen. To understand the structural and thermodynamic effects of Pro substitutions, it was introduced at 13 different positions in four different proteins, leucine-isoleucine-valine binding protein, maltose binding protein, ribose binding protein, and thioredoxin. Three of the maltose binding protein mutants were characterized by X-ray crystallography to confirm that no structural changes had occurred upon mutation. In the remaining cases, fluorescence and CD spectroscopy were used to show the absence of structural change. Stabilities of wild type and mutant proteins were characterized by chemical denaturation at neutral pH and by differential scanning calorimetry as a function of pH. The mutants did not show enhanced stability with respect to chemical denaturation at room temperature. However, 6 of the 13 single mutants showed a small but significant increase in the free energy of thermal unfolding in the range of 0.3-2.4 kcal/mol, 2 mutants showed no change, and 5 were destabilized. In five of the six cases, the stabilization was because of reduced entropy of unfolding. However, the magnitude of the reduction in entropy of unfolding was typically several fold larger than the theoretical estimate of -4 cal K(-1) mol(-1) derived from the relative areas in the Ramachandran map accessible to Pro and Ala residues, respectively. Two double mutants were constructed. In both cases, the effects of the single mutations on the free energy of thermal unfolding were nonadditive.

It is now recognized that acquiring specific skills in self-evaluation helps students in a more general appraisal of their overall performance. Self- and peer-evaluation skills are essential prerequisites for the success of every doctor in maintaining professional competence. In the Faculty of Medicine and Health Sciences (FMHS) of the United Arab Emirates, problem-based learning (PBL) is instituted in the first year. Self-evaluation by students and tutor rating of students' performances are an integral part of the PBL tutorials. This has provided the opportunity to conduct a systematic study of the role of self-evaluation by students as distinct from the tutor evaluation of students in the PBL tutorials for five themes. The study sample included all preparatory year (first-year) students who joined the FMHS in 1994 and 1995. A total number of 64 students participated, of whom 17 (26%) were male and 47 (74%) female. Mean self-evaluation scores were high throughout the module and did not follow any trend from theme one to theme five. While self and tutor scores were similar, male student self-evaluation scores were higher than for female students on overall scores. The sharing of assessment reports between students and tutors has been perceived to be a useful tool for the students' development of the skills of analysis, differentiation and critical appraisal.

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