Entropy and Barrier-Hopping Determine Conformational Viscoelasticity in Single Biomolecules

Biological macromolecules have complex and non-trivial energy landscapes, endowing them a unique conformational adaptability and diversity in function. Hence, understanding the processes of elasticity and dissipation at the nanoscale is important to molecular biology and also emerging fields such as nanotechnology. Here we analyse single molecule fluctuations in an atomic force microscope (AFM) experiment using a generic model of biopolymer viscoelasticity that importantly includes sources of local `internal' conformational dissipation. Comparing two biopolymers, dextran and cellulose, polysaccharides with and without the well-known `chair-to-boat' transition, reveals a signature of this simple conformational change as minima in both the elasticity and internal friction around a characteristic force. A calculation of two-state populations dynamics offers a simple explanation in terms of an elasticity driven by the entropy, and friction by barrier-controlled hopping, of populations on a landscape. The microscopic model, allows quantitative mapping of features of the energy landscape, revealing unexpectedly slow dynamics, suggestive of an underlying roughness to the free energy.Comment: 25 pages, 7 figures, naturemag.bst, modified nature.cls (naturemodified.cls

The ruff of equatorial emission around the SS433 jets: its spectral index and origin

We present unique radio observations of SS433, using MERLIN, the VLBA, and the VLA, which allow us to, for the first time, properly image and derive a meaningful spectral index for the `ruff' of equatorial emission which surrounds SS433's jet. We interpret this smooth ruff as a wind-like outflow from the binary.Comment: 4 pages, 4 figures, to appear in Proceedings of the 4th Microquasar Workshop, eds. Ph Durouchoux, Y. Fuchs and J. Rodrigue

When Voting Becomes Protest:Mapping Determinants of Collective Action Onto Voting Behavior

Do people signal protest by bringing out a protest vote when they feel they have been collectively disadvantaged? Political scientists have been interested in "protest voting" yet theoretical understanding is limited. Social psychologists have studied other forms of collective protest extensively. The present study integrates insights from the political science approach to protest voting and the social psychological approach to protest behavior to study how a context of perceived collective disadvantage influences voting for protest parties. We conducted a field study with a quasi-experimental design. This allowed us to study effects of a plausibly exogenous variable-the presence versus absence of societal disadvantage (the experience of man-made earthquakes)-on both determinants of and on subsequent protest voting. Results reveal that the presence of earthquakes affects levels of protest voting via (national) trust, regional identification, and perceptions of efficacy.</p

The AFF4 scaffold binds human P-TEFb adjacent to HIV Tat.

Human positive transcription elongation factor b (P-TEFb) phosphorylates RNA polymerase II and regulatory proteins to trigger elongation of many gene transcripts. The HIV-1 Tat protein selectively recruits P-TEFb as part of a super elongation complex (SEC) organized on a flexible AFF1 or AFF4 scaffold. To understand this specificity and determine if scaffold binding alters P-TEFb conformation, we determined the structure of a tripartite complex containing the recognition regions of P-TEFb and AFF4. AFF4 meanders over the surface of the P-TEFb cyclin T1 (CycT1) subunit but makes no stable contacts with the CDK9 kinase subunit. Interface mutations reduced CycT1 binding and AFF4-dependent transcription. AFF4 is positioned to make unexpected direct contacts with HIV Tat, and Tat enhances P-TEFb affinity for AFF4. These studies define the mechanism of scaffold recognition by P-TEFb and reveal an unanticipated intersubunit pocket on the AFF4 SEC that potentially represents a target for therapeutic intervention against HIV/AIDS. DOI:http://dx.doi.org/10.7554/eLife.00327.001

An Interactive, Mobile-Based Tool for Personal Social Network Data Collection and Visualization Among a Geographically Isolated and Socioeconomically Disadvantaged Population: Early-Stage Feasibility Study with Qualitative User Feedback

Background: Personal social networks have a profound impact on our health, yet collecting personal network data for use in health communication, behavior change, or translation and dissemination interventions has proved challenging. Recent advances in social network data collection software have reduced the burden of network studies on researchers and respondents alike, yet little testing has occurred to discover whether these methods are: (1) acceptable to a variety of target populations, including those who may have limited experience with technology or limited literacy; and (2) practical in the field, specifically in areas that are geographically and technologically disconnected, such as rural Appalachian Kentucky. Objective: We explored the early-stage feasibility (Acceptability, Demand, Implementation, and Practicality) of using innovative, interactive, tablet-based network data collection and visualization software (OpenEddi) in field collection of personal network data in Appalachian Kentucky. Methods: A total of 168 rural Appalachian women who had previously participated in a study on the use of a self-collected vaginal swab (SCVS) for human papillomavirus testing were recruited by community-based nurse interviewers between September 2013 and August 2014. Participants completed egocentric network surveys via OpenEddi, which captured social and communication network influences on participation in, and recruitment to, the SCVS study. After study completion, we conducted a qualitative group interview with four nurse interviewers and two participants in the network study. Using this qualitative data, and quantitative data from the network study, we applied guidelines from Bowen et al to assess feasibility in four areas of early-stage development of OpenEddi: Acceptability, Demand, Implementation, and Practicality. Basic descriptive network statistics (size, edges, density) were analyzed using RStudio. Results: OpenEddi was perceived as fun, novel, and superior to other data collection methods or tools. Respondents enjoyed the social network survey component, and visualizing social networks produced thoughtful responses from participants about leveraging or changing network content and structure for specific health-promoting purposes. Areas for improved literacy and functionality of the tool were identified. However, technical issues led to substantial (50%) data loss, limiting the success of its implementation from a researcher\u27s perspective, and hindering practicality in the field. Conclusions: OpenEddi is a promising data collection tool for use in geographically isolated and socioeconomically disadvantaged populations. Future development will mitigate technical problems, improve usability and literacy, and test new methods of data collection. These changes will support goals for use of this tool in the delivery of network-based health communication and social support interventions to socioeconomically disadvantaged populations

Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

This document is the final technical report for Cooperative Agreement DE-FC26-04NT41992, 'Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,' which was conducted over the time-period January 1, 2004 through December 31, 2010. The objective of this project has been to demonstrate at pilot scale the use of solid catalysts and/or fixed-structure mercury sorbents to promote the removal of total mercury and oxidation of elemental mercury in flue gas from coal combustion, followed by wet flue gas desulfurization (FGD) to remove the oxidized mercury at high efficiency. The project was co-funded by the U.S. DOE National Energy Technology Laboratory (DOE-NETL), EPRI, Great River Energy (GRE), TXU Energy (now called Luminant), Southern Company, Salt River Project (SRP) and Duke Energy. URS Group was the prime contractor. The mercury control process under development uses fixed-structure sorbents and/or catalysts to promote the removal of total mercury and/or oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone FGD systems. Oxidized mercury not adsorbed is removed in the wet FGD absorbers and leaves with the byproducts from the FGD system. The project has tested candidate materials at pilot scale and in a commercial form, to provide engineering data for future full-scale designs. Pilot-scale catalytic oxidation tests have been completed for periods of approximately 14 to19 months at three sites, with an additional round of pilot-scale fixed-structure sorbent tests being conducted at one of those sites. Additionally, pilot-scale wet FGD tests have been conducted downstream of mercury oxidation catalysts at a total of four sites. The sites include the two of three sites from this project and two sites where catalytic oxidation pilot testing was conducted as part of a previous DOE-NETL project. Pilot-scale wet FGD tests were also conducted at a fifth site, but with no catalyst or fixed-structure mercury sorbent upstream. This final report presents and discusses detailed results from all of these efforts, and makes a number of conclusions about what was learned through these efforts

Scribing Method for Carbon Perovskite Solar Modules

The fully printable carbon triple-mesoscopic perovskite solar cell (C-PSC) has already demonstrated good efficiency and long-term stability, opening the possibility of lab-to-fab transition. Modules based on C-PSC architecture have been reported and, at present, are achieved through the accurate registration of each of the patterned layers using screen-printing. Modules based on this approach were reported with geometric fill factor (g-FF) as high as 70%. Another approach to create the interconnects, the so-called scribing method, was reported to achieve more than 90% g-FF for architectures based on evaporated metal contacts, i.e., without a carbon counter electrode. Here, for the first time, we adopt the scribing method to selectively remove materials within a C-PSC. This approach allowed a deep and selective scribe to open an aperture from the transparent electrode through all the layers, including the blocking layer, enabling a direct contact between the electrodes in the interconnects. In this work, a systematic study of the interconnection area between cells is discussed, showing the key role of the FTO/carbon contact. Furthermore, a module on 10 × 10 cm2 substrate with the optimised design showing efficiency over 10% is also demonstrated

Must Do @ VCU

Must Do @ VCU is a set of annual collegial activities that can be performed throughout the year, by faculty, staff and students. These VCU-centered activities are considered to be the things that give VCU its identity. The goal of Must Do @ VCU is to generate a sense of community and of belonging to the University. VCU is a relatively new University and its traditions are therefore not well-established. Must Do @ VCU aims to build on shared experiences as a method to establish VCU culture

Feasibility study of the Home-based Exercises for Responsible Sex (HERS) intervention to promote correct and consistent condom use among young women.

Background Male condoms are effective in preventing common sexually transmitted infections (STIs) and unintended pregnancy, if used correctly and consistently. However, condom use errors and problems are common and young people report negative experiences, such as reduced pleasure. The Kinsey Institute Home-Based Exercises for Responsible Sex (KIHERS) is a novel condom promotion intervention for young women, which aims to reduce condom errors and problems, increase self-efficacy and improve attitudes towards condoms, using a pleasure-focussed approach. The study objective was to test the operability, viability and acceptability of an adapted version of the KIHERS intervention with young women aged 16–25 years in the United Kingdom (UK) (Home-Based Exercises for Responsible Sex-UK (HERS-UK). Methods A repeated-measures single-arm design was used, with a baseline (T1) and two follow-up assessments (T2 and T3), conducted 4 weeks and 8 weeks post intervention over a 3-month period. Participants were provided a condom kit containing different condoms and lubricants and were asked to experiment with condoms alone using a dildo and/or with a sexual partner. Ten process evaluation interviews were conducted post intervention. Results Fifty-five young women received the intervention; 36 (65%) completed T2 and 33 (60%) completed T3. Condom use errors and problems decreased, self-efficacy increased and attitudes towards condoms improved significantly. The proportion of participants who reported using a condom for intercourse in the past 4 weeks increased from T1 (20; 47%) to T2 (27; 87%) and T3 (23; 77%) and using lubricant with a condom for intercourse increased from T1 (6; 30%) to T2 (13; 48%)) and T3 (16; 70%). However, motivation to use condoms did not change. Cronbach’s alpha scores indicated good internal consistency of measures used. Qualitative data provided strong evidence for the acceptability of the intervention. Conclusions HERS-UK was implemented as intended and the recruitment strategy was successful within a college/university setting. This feasibility study provided an early indication of the potential effectiveness and acceptability of the intervention, and the benefits of using a pleasure-focussed approach with young women. Measures used captured change in outcome variables and were deemed fit for purpose. Future research should explore cost-effectiveness of this intervention, in a large-scale controlled trial using a diverse sample and targeting young women most at risk of STIs