Rensselaer Polytechnic Institute

About: Rensselaer Polytechnic Institute is a education organization based out in Troy, New York, United States. It is known for research contribution in the topics: Terahertz radiation & Finite element method. The organization has 19024 authors who have published 39922 publications receiving 1414699 citations. The organization is also known as: RPI & Rensselaer Institute.

Optogenetic protein clustering and signaling activation in mammalian cells

Abstract: We report an optogenetic method based on Arabidopsis thaliana cryptochrome 2 for rapid and reversible protein oligomerization in response to blue light. We demonstrated its utility by photoactivating the β-catenin pathway, achieving a transcriptional response higher than that obtained with the natural ligand Wnt3a. We also demonstrated the modularity of this approach by photoactivating RhoA with high spatiotemporal resolution, thereby suggesting a previously unknown mode of activation for this Rho GTPase.

Negative effects of destructive criticism: impact on conflict, self-efficacy, and task performance.

Abstract: In Study 1, 83 undergraduates received either constructive criticism (feedback that was specific, considerate, and did not attribute poor performance to internal causes) or destructive criticism (feedback that violated these basic principles) of their work. Those who received destructive criticism reported greater anger and tension and indicated that they would be more likely to handle future disagreements with the source through resistance or avoidance and less likely to handle disagreements through collaboration or compromise. In Study 2, 106 undergraduates who received destructive criticism of their work on an initial task set lower goals and reported lower self-efficacy on two additional tasks than did subjects who received constructive criticism or no feedback. In Study 3, 108 employees of a large food-processing company rated the importance of 14 potential causes of conflict in their organization. Poor use of criticism was perceived as a more important cause of conflict and received higher ratings than did competition over resources or disputes overjurisdiction.

Superhydrophobic to superhydrophilic wetting control in graphene films.

Abstract: Adv. Mater. 2010, 22, 2151–2154 2010 WILEY-VCH Verlag G T IO N Superhydrophobic materials with water contact angles above 1508 are the key enabler for antisticking, anticontamination, and self-cleaning technologies. Similarly, superhydrophilic materials with water contact angles below 108 have many important applications; for example, as a wicking material in heat pipes and for enhanced boiling heat transfer. In general, the wettability of a solid surface is strongly influenced both by its chemical composition and by its geometric structure (or surface roughness). Several experimental and modeling studies have focused on exploiting surface roughness to engineer superhydrophobicity or superhydrophilicity. Both microscale roughness features (e.g., micromachined silicon pillars) as well as nanoscale features (e.g., aligned arrays of carbon nanotubes) have been investigated. However, so far the wetting properties of graphene-based coatings have not been studied in detail. Graphene is a single-atom-thick sheet of sp hybridized carbon atoms. When deposited on a planer substrate, the individual graphene sheets form an interconnected film, which increases the surface roughness of the substrate by one to two orders of magnitude. We demonstrate here that this roughness effect in conjunction with the surface chemistry of the graphene sheets can be used to dramatically alter the wettability of the substrate. If hydrophilic graphene sheets are used (for example, by sonicating the as-produced graphene in water), the substrate acquires a superhydrophilic character. Conversely if hydrophobic graphene sheets are used (by sonicating the as-produced graphene in acetone) then the roughness effect imparts superhydrophobicity to the underlying substrate. By controlling the relative proportion of acetone and water in the solvent, the contact angle of the resulting graphene film can be tailored over a wide range (from superhydrophobic to superhydrophilic). Such graphene-based coatings with controllable wetting properties provide a facile and effective means to modify the wettability of a variety of surfaces. The graphene sheets used in this study were extracted from graphite using the method developed in Reference [19,20]. In this method, partially oxygenated graphene sheets are generated by the rapid thermal expansion (>2000 8C min ) of completely oxidized graphite oxide. The protocols used to oxidize graphite to graphite oxide and then generate graphene sheets (Fig. 1a) by the thermal exfoliation of graphite oxide are provided in the Experimental section. Figure 1b illustrates a transmission electron microscopy (TEM) image of a typical graphene flake synthesized by the above method and deposited on a standard TEM grid for imaging. The flake is several micrometers in dimension; note the wrinkled (rough) surface texture of the graphene flake. Figure 1c displays a high-resolution TEM (HRTEM) image of the edge of a typical graphene flake, indicating that each flake is comprised of 3 individual graphene sheets. The electron diffraction pattern (shown in inset) confirms the signature of few-layered graphene.

Admissibility criteria for propagating phase boundaries in a van der Waals fluid

Abstract: : This paper gives admissibility criteria for weak solutions to the partial differential equations governing isothermal motion of a van der Waals fluid. The main issue is that an admissibility criterion based on viscosity alone is too restrictive - it rules out all slowly propagating phase boundaries. Instead a criterion based on viscosity and capillarity is proposed. The viscosity-capillarity condition is studied and shown to imply that the state on one side of a phase boundary specifies both the speed of the phase boundary and the state of the other side of the phase boundary (a result which is different from classical gas dynamics).