Tegrity: Successes and Failures of a Pilot Program Introducing Lecture Capture to Campus

This presentation will detail the implementation and evaluation of Tegrity Campus 2.0 on the campus of Wichita State University. Presenters will discuss what did and did not work, including considerations for adoption, deploying hardware, training, and how lessons learned can be applied to other campuses evaluating new products or software

Best-in-Class Global Bumper Reinforcement Beam

Modern bumper systems are governed by laws and regulations imposed separately by various countries. Today, the regulations in China, North America, and Europe are becoming more similar, but there is not a widely accepted bumper reinforcement that meets the requirements of all markets around the globe. A universal bumper reinforcement beam incorporating Plug-n-Play techniques was developed to meet and exceed all testing requirements and performance standards of each country. These Plug-n-Play techniques consist of adding energy absorbing attachments to the front of a base bumper beam. Simple beam analysis and FEA were the primary analysis tools in the development of the bumper beam system. Plug & Play techniques were utilized to increase the performance of the universal bumper across all markets

Pairwise Interactions between Linear Alkanes in Water Measured by AFM Force Spectroscopy

Pairwise interactions between n-alkanes from decane to octadecane in water have been studied by single-molecule force spectroscopy. The interacting molecules are covalently tethered to the glass substrate and to the probe of an atomic force microscope by water-soluble linkers to facilitate single-molecule detection. However, the measured distribution of rupture forces deviates significantly from the distribution predicted by theoretical models for rupture of individual bonds. To describe the statistics of rupture forces, an analytical model that considers near-simultaneous rupture of two bonds loaded by tethers with different lengths is introduced. The common most probable force analysis approach is used for comparison. In both data analyses, the possible systematic errors due to nonlinear elasticity of polymeric tethers and variations in the shape of the potential of mean force were considered. Experimental distributions of rupture forces are well-fit by the two-bond rupture model using a single set of kinetic parameters for different experiments, while the most probable force approach yields parameters that vary significantly for different samples. The measured activation energies for dissociation of alkanes are close to the free energies predicted by cavity models of hydrophobic interactions. The surface free-energy density is estimated to be ∼21 kJ/(mol nm^2) and is close to the upper limit of free energies used in the computer simulations of hydrophobic interactions in proteins. In contrast to the predictions of the cavity models, the measured activation energy does not increase monotonically with increase in alkane chain size. To explain this discrepancy and the measured distance to the transition-state barrier (∼0.6 nm), it is suggested that alkanes undergo conformational transition to the collapsed state upon dimerization. Change in the alkane conformation from extended to helical has been observed previously for binding of alkanes in water to hydrophobic synthetic receptors. Here, however, conformational change is suggested without geometrical constraints imposed by small cavitands. The proposed collapsed state of the alkane dimers has implications for the kinetics of self-assembly of surfactant micelles

Effects of Multiple-Bond Ruptures in Force Spectroscopy Measurements of Interactions between Fullerene C_(60) Molecules in Water

Interactions between fullerene C_(60) molecules in water were measured by force spectroscopy. Fullerene molecules were covalently connected to bifunctional water-soluble poly(ethylene glycol) (PEG) linkers and subsequently tethered to the substrate and to the tip of the atomic force microscope to facilitate single molecule detection and avoid spurious surface effects. The distributions of rupture forces for substrates prepared with different incubation times of C_(60)-PEG-NH_2 exhibit high rupture forces that cannot be explained by the theoretical distribution of single molecule binding. Moreover, the relative amplitude of the high force peak in the histogram increases with incubation time. These observations are explained by attributing the measured high forces to the rupture of multiple bonds between fullerene molecules. Force spectroscopy data analysis based on the most probable forces gives significantly different dissociation rates for samples that exhibit different amplitudes of the high force peak. An approximate analytical model that considers ruptures of two bonds that are simultaneously loaded by tethers with different lengths is proposed. This model successfully fits the distributions of the rupture forces using the same set of kinetic parameters for samples prepared with different grafting densities. It is proposed that this model can be used as a common tool to analyze the probability distributions of rupture forces that contain peaks or shoulders on the high force side of the distribution

Anisotropy of Pairwise Interactions between Hexadecanes in Water Measured by AFM Force Spectroscopy

The pulling coordinate dependence of hexadecane dimer dissociation in water was studied using AFM-based single molecule force spectroscopy. Hexadecanes were covalently bound to both the AFM cantilever and to the glass substrates through hydrophilic poly-(ethylene glycol) tethers. The polymer tether was attached either to the end of hexadecane or in the middle of the molecule. Experimentally studied configurations of hexadecanes tethered to the AFM probe and to the glass substrate include a symmetric end-attached configuration (EE), an asymmetric end-attached vs middle-attached configuration (ME), and a symmetric middle-attached configuration (MM). Kinetic parameters of the distance to the transition state barrier (barrier width) and activation energy of dissociation were extracted from the statistical analysis of double tether rupture events. The rupture force analysis employs a recently introduced two-bond model that corrects for errors induced by potential multiple simultaneous rupture events and accounts for the tether stiffening effects. Effects of the shape of intermolecular potential were considered by using the Bell−Evans and Hummer−Szabo force spectroscopy models. The activation energies to dissociation were similar for all configurations while the barrier width was significantly shorter for the MM and ME configurations than for EE configurations. Primitive models that include touching or merging spherical or cylindrical shapes were considered. These models were inconsistent with the extracted kinetic parameters. It is suggested that the observed anisotropy may be a result of conformational transition of hexadecane from extended to collapsed state during dimerization. A flexible four-bead model of hexadecane was introduced to account for conformational flexibility. Using the length and solvent accessible surface area of hexadecane, the four-bead model gave molecular dissociation parameters consistent with the experimental data. This suggests that conformational flexibility is an important factor in hydrophobic interactions between alkane chains

A lean neck mass clinic model: Adding value to care

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115945/1/lary25535.pd

Pairwise Interactions between Linear Alkanes in Water Measured by AFM Force Spectroscopy

Pairwise interactions between n-alkanes from decane to octadecane in water have been studied by single-molecule force spectroscopy. The interacting molecules are covalently tethered to the glass substrate and to the probe of an atomic force microscope by water-soluble linkers to facilitate single-molecule detection. However, the measured distribution of rupture forces deviates significantly from the distribution predicted by theoretical models for rupture of individual bonds. To describe the statistics of rupture forces, an analytical model that considers near-simultaneous rupture of two bonds loaded by tethers with different lengths is introduced. The common most probable force analysis approach is used for comparison. In both data analyses, the possible systematic errors due to nonlinear elasticity of polymeric tethers and variations in the shape of the potential of mean force were considered. Experimental distributions of rupture forces are well-fit by the two-bond rupture model using a single set of kinetic parameters for different experiments, while the most probable force approach yields parameters that vary significantly for different samples. The measured activation energies for dissociation of alkanes are close to the free energies predicted by cavity models of hydrophobic interactions. The surface free-energy density is estimated to be ∼21 kJ/(mol nm^2) and is close to the upper limit of free energies used in the computer simulations of hydrophobic interactions in proteins. In contrast to the predictions of the cavity models, the measured activation energy does not increase monotonically with increase in alkane chain size. To explain this discrepancy and the measured distance to the transition-state barrier (∼0.6 nm), it is suggested that alkanes undergo conformational transition to the collapsed state upon dimerization. Change in the alkane conformation from extended to helical has been observed previously for binding of alkanes in water to hydrophobic synthetic receptors. Here, however, conformational change is suggested without geometrical constraints imposed by small cavitands. The proposed collapsed state of the alkane dimers has implications for the kinetics of self-assembly of surfactant micelles

Development of the Continuously Variable Volume Reactor for Flow Injection AnalysisDesign, Capabilities and Testing

A new apparatus for mixing sample and reagent in flow injection analysis is described. The continuously variable volume reactor (CVVR) replaces the conventional mixing coil in a flow injection manifold to provide mixing and dilution. A linear actuator motor allows control of the chamber volume via Lab VIEW software. The chamber volume can be incremented in steps of 1 uL over the range 68-1704 uL. In addition, the chamber has an integral variable-speed stirring unit that is also under computer control. Experiments were performed to evaluate the dispersion characteristics of this new device, evaluate the volume reproducibility, and understand the mixing characteristics. Use of the chamber is shown in the determination of iron (II) in pond water, and in NIST SRM 1643d with excellent results and a detection limit of 3.7 ug/L iron(II). Advantages of the CVVR and future research activities using the device are discussed