Analyzing the Safety Effects of Edge Lane Roads for all Road Users

This thesis acts as one of the first studies that analyzes the safety effects of Edge Lane Roads (ELR) for all road users. This is important since ELRs can be a solution to many issues, such as alleviating congestion, increasing multimodality along roadways, and reducing maintenance costs. ELRs in both North America and Australia were observed. Starting with the North American ELRs, the following study designs were employed to estimate the safety of ELRs: (a) yoked comparison where each ELR installation was matched with at least two comparable 2-lane roads to serve as comparison sites and (b) an Empirical Bayes (EB) before/after analysis for ELR sites where requisite data on AADT and other relevant characteristics were available. Crash data was collected and compiled into four different groups: ELR before implementation, ELR after implementation, comparison site before ELR implementation, and comparison site after ELR comparison. The yoked comparison showed 9 of the 13 sites that had lower crash counts compared to their respective comparison sites. The EB analysis showed all 11 ELRs that were observed demonstrated a reduction in crashes. Moving to the Australian ELRs, the following study designs were employed: (c) analysis of general crash counts/trends, and (d) reverse EB analysis. The analysis of general crash counts and trends showed that each of the Australian ELRs exhibited very low amounts of crashes for 5 years, which further shows how safe these facilities are. Moving forward to the reverse EB analysis, 5 of the 8 ELR sites demonstrated a reduction in crashes. Overall, the results were generally favorable and indicated that ELRs provided a safer experience for cyclists, drivers, and pedestrians. More analysis is recommended as more data becomes available on these ELRs. Examples of this include using pedestrian and bicycle data to better understand the safety effects VRUs experience on North American facilities or gathering enough crash data to conduct 3-year reverse EB analyses for ELRs that were expanded to 2-lane roads. Hence, a recommendation can be made to implement a few experimental ELRs in rural locations throughout the State of California to help it meet its SB-1 objectives

The Synergistic Contribution of Lactobacillus and Dietary Phytophenols in Host Health

Phytophenols are found ubiquitously among all plants. They are important in diets rich in fruits and vegetables because these compounds provide health benefits to the host, ultimately decreasing the incidence of chronic diseases. These compounds act as natural antioxidants and provide anti-inflammatory, antiviral, antibiotic, and antineoplastic properties. Reactive oxygen species (ROS) are produced under normal physiological functions, and low/moderate levels are required for cellular turnover and signaling. However, when ROS levels become too high, oxidative stress can occur. Phytophenols quench ROS and ultimately avoid the damaging effects ROS elicit on the cell. The highest source of bioavailable phytophenols comes from our diet as a component usually esterified in plant fiber. For phytophenols to be absorbed by the body, they must be released by esterases, or other related enzymes. The highest amount of esterase activity comes from the gastrointestinal (GI) microbiota; therefore, the host requires the activity of mutualistic bacteria in the GI tract to release absorbable phytophenols. For this reason, mutualistic bacteria have been investigated for beneficial properties in the host. Our laboratory has begun studying the interaction of Lactobacillus johnsonii N6.2 with the host since it was found to be negatively correlated with type 1 diabetes (T1D). Analyses of this strain have revealed two important characteristics: (1) It has the ability to release phytophenols from dietary fiber through the secretion of two strong cinnamoyl esterases and (2) L. johnsonii also has the ability to generate significant amounts of H2O2, controlling the activity of indoleamine 2,3-dioxygenase (IDO), an immunomodulatory enzyme

Controlling suction by vapour equilibrium technique at different temperatures, application to the determination of the water retention properties of MX80 clay

Problems related to unsaturated soils are frequently encountered in geotechnical or environmental engineering works. In most cases, for the purpose of simplicity, the problems are studied by considering the suction effects on volume change or shear strength under isothermal conditions. Under isothermal condition, very often, a temperature independent water retention curve is considered in the analysis, which is obviously a simplification. When the temperature changes are too significant to be neglected, it is necessary to account for the thermal effects. In this paper, a method for controlling suction using the vapour equilibrium technique at different temperatures is presented. First, calibration of various saturated saline solutions was carried out from temperature of 20 degrees C to 60 degrees C. A mirror psychrometer was used for the measurement of relative humidity generated by saturated saline solutions at different temperatures. The results obtained are in good agreement with the data from the literature. This information was then used to determine the water retention properties of MX80 clay, which showed that the retention curve is shifting down with increasing of temperature

Localized Heating Near a Rigid Spherical Inclusion in a Viscoelastic Binder Material Under Compressional Plane Wave Excitation

High-frequency mechanical excitation has been shown to generate heat within composite energetic materials and even induce reactions in single energetic crystals embedded within an elastic binder. To further the understanding of how wave scattering effects attributable to the presence of an energetic crystal can result in concentrated heating near the inclusion, an analytical model is developed. The stress and displacement solutions associated with the scattering of compressional plane waves by a spherical obstacle (Pao and Mow, 1963, “Scattering of Plane Compressional Waves by a Spherical Obstacle,” J. Appl. Phys., 34(3), pp. 493–499) are modified to account for the viscoelastic effects of the lossy media surrounding the inclusion (Gaunaurd and Uberall, 1978, “Theory of Resonant Scattering From Spherical Cavities in Elastic and Viscoelastic Media,” J. Acoust. Soc. Am., 63(6), pp. 1699–1712). The results from this solution are then utilized to estimate the spatial heat generation due to the harmonic straining of the material, and the temperature field of the system is predicted for a given duration of time. It is shown that for certain excitation and sample configurations, the elicited thermal response near the inclusion may approach, or even exceed, the decomposition temperatures of various energetic materials. Although this prediction indicates that viscoelastic heating of the binder may initiate decomposition of the crystal even in the absence of defects such as initial voids or debonding between the crystal and binder, the thermal response resulting from this bulk heating phenomenon may be a precursor to dynamic events associated with such crystal-scale effects

Selective excitation of individual nanoantennas by pure spectral phase control in the ultrafast coherent regime

Coherent control is an ingenious tactic to steer a system to a desired optimal state by tailoring the phase of an incident ultrashort laser pulse. A relevant process is the two-photon–induced photoluminescence (TPPL) of nanoantennas, as it constitutes a convenient route to map plasmonic fields, and has important applications in biological imaging and sensing. Unfortunately, coherent control of metallic nanoantennas is impeded by their ultrafast femtosecond dephasing times so far limiting control to polarization and spectral optimization. Here, we report that phase control of the TPPL in resonant gold nanoantennas is possible. We show that, by compressing pulses shorter than the localized surface plasmon dephasing time (<20 fs), a very fast coherent regime develops, in which the two-photon excitation is sensitive to the phase of the electric field and can therefore be controlled. Instead, any phase control is gone when using longer pulses. Finally, we demonstrate pure phase control by resorting to a highly sensitive closed-loop strategy, which exploits the phase differences in the ultrafast coherent response of different nanoantennas, to selectively excite a chosen antenna. These results underline the direct and intimate relation between TPPL and coherence in gold nanoantennas, which makes them interesting systems for nanoscale nonlinear coherent control.Peer ReviewedPostprint (published version

Rapid and robust control of single quantum dots

The combination of single particle detection and ultrafast laser pulses is an instrumental method to track dynamics at the femtosecond time scale in single molecules, quantum dots and plasmonic nanoparticles. Optimal control of the extremely short-lived coherences of these individual systems has so far remained elusive, yet its successful implementation would enable arbitrary external manipulation of otherwise inaccessible nanoscale dynamics. In ensemble measurements, such control is often achieved by resorting to a closed-loop optimization strategy, where the spectral phase of a broadband laser field is iteratively optimized. This scheme needs long measurement times and strong signals to converge to the optimal solution. This requirement is in conflict with the nature of single emitters whose signals are weak and unstable. Here we demonstrate an effective closed-loop optimization strategy capable of addressing single quantum dots at room temperature, using as feedback observable the two-photon photoluminescence induced by a phase-controlled broadband femtosecond laser. Crucial to the optimization loop is the use of a deterministic and robust-against-noise search algorithm converging to the theoretically predicted solution in a reduced amount of steps, even when operating at the few-photon level. Full optimization of the single dot luminescence is obtained within similar to 100 trials, with a typical integration time of 100 ms per trial. These times are faster than the typical photobleaching times in single molecules at room temperature. Our results show the suitability of the novel approach to perform closed-loop optimizations on single molecules, thus extending the available experimental toolbox to the active control of nanoscale coherences

Laccase gene silencing negatively effects growth and development in Pleurotus ostreatus

42-51In this study we describe the effects of Pleurotus ostreatus transformants that have been silenced for laccase genes. Using the RNAi strategy, transformants with different levels of phenotypic alteration were obtained with respect to their oxidation capacity of 2,6-dimethoxyphenol (DMP). The analysis of laccase activity on DMP allowed us to select transformants with severe, medium and light phenotypic alteration in comparison to the PoB strain. The measurements of the average growth rate of the transformants with severe phenotypic alteration suggested that laccase expression could play a role in the vegetative growth of P. ostreatus. It was observed that both in solid and liquid cultures, PoB and the transformants express mRNA for lacc10, although the transformants with medium and severe phenotypic alteration present a decrease in intensity, especially in solid culture. This suggests that the product of this gene is responsible for the development of the mycelium and probably participates in the production of biomass in solid culture and also could be related to the decrease in the intensity of the constant isoenzyme observed in both culture systems

Polycrystalline Ni nanotubes under compression: a molecular dynamics study

Mechanical properties of nanomaterials, such as nanowires and nanotubes, are an important feature for the design of novel electromechanical nano-architectures. Since grain boundary structures and surface modifications can be used as a route to modify nanostructured materials, it is of interest to understand how they affect material strength and plasticity. We report large-scale atomistic simulations to determine the mechanical response of nickel nanowires and nanotubes subject to uniaxial compression. Our results suggest that the incorporation of nanocrystalline structure allows completely flexible deformation, in sharp contrast with single crystals. While crystalline structures at high compression are dominated by dislocation pinning and the multiplication of highly localized shear regions, in nanocrystalline systems the dislocation distribution is significantly more homogeneous. Therefore, for large compressions (large strains) coiling instead of bulging is the dominant deformation mode. Additionally, it is observed that nanotubes with only 70% of the nanowire mass but of the same diameter, exhibit similar mechanical behavior up to 0.3 strain. Our results are useful for the design of new flexible and light-weight metamaterials, when highly deformable struts are required.Fil: Rojas Nunez, J.. Universidad de Santiago de Chile; ChileFil: Baltazar, S. E.. Universidad de Santiago de Chile; ChileFil: Gonzalez, R. I.. Universidad Mayor; ChileFil: Bringa, Eduardo Marcial. Universidad Mayor; Chile. Universidad de Mendoza. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Allende, S.. Universidad de Santiago de Chile; ChileFil: Kiwi, M.. Universidad de Santiago de Chile; ChileFil: Valencia, F. J.. Universidad de Santiago de Chile; Chile. Universidad Mayor; Chil