We perform molecular-dynamics simulations of a supported molecular thin film. By varying thickness and temperature, we observe anisotropic mobility as well as strong gradients of both the vibrational motion and the structural relaxation through film layers with monomer-size thickness. We show that the gradients of the fast and the slow dynamics across the layers (except the adherent layer to the substrate) comply, without any adjustment, with the same scaling between the structural relaxation time and the DebyeWaller factor originally observed in the bulk [Larini et al., Nat. Phys., 2008, 4, 42]. The scaling is not observed if the average dynamics of the film is inspected. Our results suggest that the solidification process of each layer may be tracked by knowing solely the vibrational properties of the layer and the bulk.
We
use MD simulations to study the pore translocation properties
of a pseudoknotted viral RNA. We consider the 71-nucleotide-long xrRNA
from the Zika virus and establish how it responds when driven through
a narrow pore by static or periodic forces applied to either of the
two termini. Unlike the case of fluctuating homopolymers, the onset
of translocation is significantly delayed with respect to the application
of static driving forces. Because of the peculiar xrRNA architecture,
activation times can differ by orders of magnitude at the two ends.
Instead, translocation duration is much smaller than activation times
and occurs on time scales comparable at the two ends. Periodic forces
amplify significantly the differences at the two ends, for both activation
times and translocation duration. Finally, we use a waiting-times
analysis to examine the systematic slowing downs in xrRNA translocations
and associate them to the hindrance of specific secondary and tertiary
elements of xrRNA. The findings provide a useful reference to interpret
and design future theoretical and experimental studies of RNA translocation.
We use MD simulations to study the pore translocation properties of a pseudoknotted viral RNA. We consider the 71-nucleotide long xrRNA from Zika virus and establish how it responds when driven through a narrow pore by static or periodic forces applied to either one of the two termini. Unlike the case of fluctuating homopolymers, the onset of translocation is significantly delayed with respect to the application of static driving forces. Because of the peculiar xrRNA architecture, activation times can differ by orders of magnitude at the two ends. Instead, translocation duration is much smaller than activation times and occurs on timescales comparable at the two ends. Periodic forces amplify significantly the differences at the two ends, both for activation times and translocation duration. Finally, we use a waiting-times analysis to examine the systematic slowing-downs in xrRNA translocations and associate them to the hindrance of specific secondary and tertiary elements of xrRNA. The findings ought to be useful as a reference to interpret and design future theoretical and experimental studies of RNA translocation.
An open challenge in self-assembly is learning how to design systems that can be conditionally guided towards different target structures depending on externally-controlled conditions. Using a theoretical and numerical approach,...
American University's Office of Information Technology (OIT) training unit provides classroom-based and online training to over 1,800 staff, students, and faculty attendees annually. This group develops, schedules, markets, and delivers the training. The training unit also evaluates the effectiveness of the training and provides detailed reporting for the university's staff performance management program.In 2011, the OIT training unit was invited to partner with the University's Human Resources department and other campus trainers to select a vendor and implement an online Learning Management System for full-time university staff, and faculty with supervisory responsibilities.The training partners went through a lengthy assessment process, chose a vendor, assigned system roles, attended extensive administrator training, and then the hard work began! Although some of the training partners shared similar technological tools and processes, generally each group had a distinct, and well-established, method for managing the administration, marketing, and assessment of their training program. Combining these methods, while maintaining each group's autonomy proved challenging. This presentation will discuss how the team leveraged the learning management technology to meet our shared goals, culminating in a successful system launch in February, 2012. We will explore how we selected the technical components we would utilize, and how we developed a common language and unified processes. We will also discuss the process of branding our new system as "ULearn," how we created a ULearn portal, and how we marketed the system. Lastly, we will explore how we are fostering a "ULearn More" environment by empowering our customers to navigate their own learning path.
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