Polymer/riblet combination for hydrodynamic skin friction reduction

A process is disclosed for reducing skin friction and inhibiting the effects of liquid turbulence in a system involving the flow of a liquid along the surface of a body, e.g., a marine vehicle. This process includes injecting a drag reducing polymer into the valleys of adjacent, evenly spaced, longitudinal grooves extending along the length of the surface of the body, so that the rate of diffusion of the polymer from individual grooves into the liquid flow is predictably controlled by the groove dimensions. When the polymer has diffused over the tips of the grooves into the near wall region of the boundary layer, the polymer effectively reduces the turbulent skin friction. A substantial drag reducing effect is achieved with less polymer than must be used to lower skin friction when the surface of the body is smooth

Nanophotonics of 2-Dimensional Materials

2-Dimensional materials are of great interest because of novel and intriguing properties that emerge at the monolayer limit in comparison to bulk materials. To that end, this thesis is split into the study of two different 2-dimensional materials in the realm of nanophotonics. First, graphene is utilized for both passivating the surface of metallic nanoparticles from oxidation and as a platform for functionalization and integration into specific molecule sensing. The nanoparticles act as plasmonic nanoantennas, enhancing the electric field near the surface of the antenna. It is shown that graphene-encapsulated silver nanoantennas are oxidation resistant and optically stable over a 30 day period. The performance of the graphene-passivated silver nanoantennas outpaces that of the traditional material, gold, by ~60% in sensing bulk index changes in the range of n = 1.40 1.45. Graphene encapsulation can be extended to other plasmonic metals such as aluminum and copper, as well as fully integrate graphene-passivated Ag nanoantennas into biomolecular sensing devices. The second topic of this thesis is to study and enhance the luminescence of molybdenum disulfide (MoS2), a 2-dimensional semiconductor. Atomic layer deposition of SiO2 was used to encapsulate and the effectively etch a layer of bilayer MoS2 through reactive processes, which result in a chemically-doped MoS2 monolayer with enhanced luminescence properties. This new enhanced layer is two orders of magnitude more luminescent than the original material and one order of magnitude over that of an exfoliated monolayer. By coupling the enhanced MoS2 to an optical microdisk cavity, highly narrow emission can be produced from the original, broad luminescence. These sharp peaks can be utilized in biomolecule sensing through functionalization of the MoS2 layer. The effects of high-intensity optical pumping of the MoS2 in these microdisk cavities are also studied. Heat generation from non-radiative recombination causes thermally enabled oxidation of the optical material. This effect is shown to be not limited to MoS2, but affects WSe2 as well. This effect is shown to be minimized through the use of pulsed excitation, and the luminescence from high Q-factor microdisks was investigated using high-fluence femtosecond optical pulses

Hydrodynamic skin-friction reduction

A process for reducing skin friction, inhibiting the effects of liquid turbulence, and decreasing heat transfer in a system involving flow of a liquid along a surface of a body includes applying a substantially integral sheet of a gas, e.g., air, immediately adjacent to the surface of the body; a marine vehicle, which has a longitudinally grooved surface in proximity with the liquid and with a surface material having high contact angle between the liquid and said wall to reduce interaction of the liquid; water, with the surface of the body; and the hull of the marine vehicle

Hydrodynamic skin-friction reduction

A process for reducing skin friction, inhibiting the effects of liquid turbulence, and decreasing heat transfer in a system involving flow of a liquid along a surface of a body includes applying a substantially integral sheet of a gas, e.g., air, immediately adjacent to the surface of the body, e.g., a marine vehicle, which has a longitudinally grooved surface in proximity with the liquid and with a surface material having high contact angle between the liquid and said wall to reduce interaction of the liquid, e.g., water, with the surface of the body, e.g., the hull of the marine vehicle

Quantification of Biomass and Cell Motion in Human Pluripotent Stem Cell Colonies

Abstract Somatic cell reprogramming to pluripotency requires an immediate increase in cell proliferation and reduction in cell size. It is unknown whether proliferation and biomass controls are similarly coordinated with early events during the differentiation of pluripotent stem cells (PSCs). This impasse exists because PSCs grow in tight clusters or colonies, precluding most quantifying approaches. Here, we investigate live cell interferometry as an approach to quantify the biomass and growth of HSF1 human PSC colonies before and during retinoic acid-induced differentiation. We also provide an approach for measuring the rate and coordination of intracolony mass redistribution in HSF1 clusters using live cell interferometry images. We show that HSF1 cells grow at a consistent, exponential rate regardless of colony size and display coordinated intracolony movement that ceases with the onset of differentiation. By contrast, growth and proliferation rates show a decrease of only ∼15% decrease during early differentiation despite global changes in gene expression and previously reported changes in energy metabolism. Overall, these results suggest that cell biomass and proliferation are regulated independent of pluripotency during early differentiation, which is distinct from what occurs with successful reprogramming

Diminishing Effectiveness of Long-Term Maintenance Topical Steroid Therapy in PPI Non-Responsive Eosinophilic Esophagitis

While topical corticosteroids are first-line therapy for eosinophilic esophagitis (EoE), the data regarding long-term effectiveness are lacking. We aimed to determine long-term histologic and endoscopic outcomes of maintenance therapy in EoE steroid responders

20th to 21st Century Relative Sea and Land Level Changes in Northern California: Tectonic Land Level Changes and their Contribution to Sea-Level Rise, Humboldt Bay Region, Northern California

Sea-level changes are modulated in coastal northern California by land-level changes due to the earthquake cycle along the Cascadia subduction zone, the San Andreas plate boundary fault system, and crustal faults. Sea-level rise (SLR) subjects ecological and anthropogenic infrastructure to increased vulnerability to changes in habitat and increased risk for physical damage. The degree to which each of these forcing factors drives this modulation is poorly resolved. We use NOAA tide gage data and ‘campaign’ tide gage deployments, Global Navigation Satellite System (GNSS) data, and National Geodetic Survey (NGS) first-order levelling data to calculate vertical land motion (VLM) rates in coastal northern California. Sea-level observations, highway level surveys, and GNSS data all confirm that land is subsiding in Humboldt Bay, in contrast to Crescent City where the land is rising. Subtracting absolute sea-level rate (~1.99 mm/year) from Crescent City (CC) and North Spit (NS) gage relative sea-level rates reveals that CC is uplifting at ~2.83 mm/year and NS is subsiding at ~3.21mm/year. GNSS vertical deformation reveals similar rates of ~2.60 mm/year of uplift at Crescent City. In coastal northern California, there is an E-W trending variation in vertical land motion that is primarily due to Cascadia megathrust fault seismogenic coupling. This interseismic subsidence also dominates the N-S variation in vertical land motion in most of the study region. There exists a second-order heterogeneous N-S trend in vertical land motion that we associate to crustal fault-related strain. There may be non-tectonic contributions to the observed VLM rates

Gastric Prolapse with Pseudocysts Following Laparoscopic Adjustable Gastric Banding

Nonpancreatic pseudocysts may be associated with gastric prolapse in patients who have undergone laparoscopic adjustable gastric banding

TIGIT Marks Exhausted T Cells, Correlates with Disease Progression, and Serves as a Target for Immune Restoration in HIV and SIV Infection.

HIV infection induces phenotypic and functional changes to CD8+ T cells defined by the coordinated upregulation of a series of negative checkpoint receptors that eventually result in T cell exhaustion and failure to control viral replication. We report that effector CD8+ T cells during HIV infection in blood and SIV infection in lymphoid tissue exhibit higher levels of the negative checkpoint receptor TIGIT. Increased frequencies of TIGIT+ and TIGIT+ PD-1+ CD8+ T cells correlated with parameters of HIV and SIV disease progression. TIGIT remained elevated despite viral suppression in those with either pharmacological antiretroviral control or immunologically in elite controllers. HIV and SIV-specific CD8+ T cells were dysfunctional and expressed high levels of TIGIT and PD-1. Ex-vivo single or combinational antibody blockade of TIGIT and/or PD-L1 restored viral-specific CD8+ T cell effector responses. The frequency of TIGIT+ CD4+ T cells correlated with the CD4+ T cell total HIV DNA. These findings identify TIGIT as a novel marker of dysfunctional HIV-specific T cells and suggest TIGIT along with other checkpoint receptors may be novel curative HIV targets to reverse T cell exhaustion

AUXIN RESPONSE FACTOR1 and AUXIN RESPONSE FACTOR2regulate senescence and floral organ abscission in Arabidopsisthaliana

In plants, both endogenous mechanisms and environmental signals regulate developmental transitions such as seed germination, induction of flowering, leaf senescence and shedding of senescent organs. Auxin response factors (ARFs) are transcription factors that mediate responses to the plant hormone auxin. We have examine