On Martin's Pointed Tree Theorem

We investigate the reverse mathematics strength of Martin's pointed tree theorem (MPT) and one of its variants, weak Martin's pointed tree theorem (wMPT)

Flow Cell Characterisation: Flow Visualisation, Pressure Drop and Mass Transport at 2D Electrodes in a Rectangular Channel

The reaction environment in a C-Flow Lab 5 × 5® laboratory-scale electrochemical flow cell was characterised in terms of fluid flow, hydraulic pressure drop and space averaged mass transport coefficient. The cell was studied in flow-by configuration with smooth, planar electrodes within its rectangular flow channels. The effect of a turbulence promoter (a polymer mesh with a volumetric porosity of 0.84) placed next to the working electrode was also evaluated. Electrolyte volumetric flow rates ranged from 0.3 to 1.5 dm3 min-1, corresponding to mean linear velocities of 2 to 10 cm s-1 past the electrode surface and channel Reynolds numbers of 53 to 265. The pressure drop was measured both over the electrode channel and through the whole cell as a function of mean linear velocity. The electrochemical performance was quantified using the limiting current technique, which was used to determine the mass transport coefficient over the same range of flow rate. Results were compared to well-characterised electrochemical flow reactors found in the literature. The mass transport enhancement factor due to the presence of the turbulence promoter was between 1.6 and 3.9 under the studied conditions. Reactant conversion in batch recirculation mode and normalised space velocity were predicted from the electrochemical plug flow reactor equation

Innate immune responses in vivo after antigen administration : implications for vaccine development

Inducing high magnitude of antibodies with epitope breadth over prolonged periods of time is likely a prerequisite to prevent several of the world’s most serious infectious diseases such as HIV-1, malaria and tuberculosis for which there are no vaccines yet. A much better understanding of the innate immune mechanisms that are critical for inducing strong responses to vaccination is therefore essential. The overall aim of this thesis was to characterize early innate immune responses in vivo after administration of antigens. This includes studies of the recruitment of immune cell subsets to the site of antigen injection (e.g. skin or muscle), local cell activation and presence of inflammatory mediators, antigen uptake and transport and finally initiation of adaptive immunity in lymph nodes (LNs). To be able to approach this in humans in vivo, we first utilized skin punch biopsies collected from sites injected with purified protein derivate (PPD), which is a mixture of mycobacterial antigens used in the tuberculin skin test (TST). By performing tissue staining of cryosections we show in paper I that several subsets of dendritic cells (DCs), including the plasmacytoid DCs (PDCs) normally not residing in skin, infiltrated the dermis in the positive TST indurations, which was in contrast to donormatched saline-injected skin. The positive TST indurations were associated with cell death and high expression of the antimicrobial peptide LL37, which together can provide means for PDC activation and IFNα production. In line with this, IFN-inducible MxA was highly expressed in the positive TST sites. We expanded the studies in paper II and DC accumulation was also found in skin biopsies taken after skin tests using antigens from either mumps virus or Candida albicans. Further, TST indurations of HIV-1+ individuals also showed DC infiltration but to a lower degree, which likely reflect on the reduced integrity of their immune system. To this end, the level of DCs in the positive TST reactions correlated with the level of infiltrating T cells. The skin antigen tests represent recall of immunological memory responses locally. To enable studies of local innate immune activation after vaccine administration and priming of naïve responses, we developed a nonhuman primate (NHP) model in the second part of the thesis. After establishing and validating protocols for sample collection and tissue processing in paper III, we examined in paper IV how the distinct vaccine adjuvants; alum (benchmark), MF59 (emulsion) or alum with TLR7 agonist, influence the innate responses leading to adaptive immunity. HIV-1 envelope glycoprotein (Env) was administered as the vaccine antigen together with the adjuvants. We found a rapid infiltration of neutrophils, monocytes and DCs to the vaccine-injected muscle with all adjuvants. Env+ cells were readily detected in the muscle and draining LNs. In line with the finding of alum-TLR7 and MF59 being superior over alum in terms of inducing both antibody- and T cell responses, alum consistently showed lower innate activation. While alum-TLR7 consistently induced robust DC maturation and type IFN I responses, MF59 induced neutrophil homing to LNs. Comparison of antigen presentation capacity of Env+ cells in the draining lymph nodes showed that myeloid DCs exceled at stimulating Env-specific CD4+ T cell responses. However, neutrophils were also capable of antigen presentation. Despite inducing different innate activation, both MF59 and alum-TLR7 enhanced the priming of Env-specific T cells in vaccine-draining LNs as well as increased the differentiation of T follicular helper cells and germinal center formations compared to alum. In summary, our findings demonstrate the initial immune events at the sites of antigen delivery, including vaccination in vivo. These early immunological responses shape the quantity and quality of adaptive immunity. Understanding the mechanisms by which distinct adjuvants influence vaccine response will help in the selection of the best-suited adjuvant to improve vaccine efficacy to a given pathogen

Palladium and silver abundances in stars with [Fe/H] > -2.6

Palladium (Pd) and silver (Ag) are the key elements for probing the weak component in the rapid neutron-capture process (r-process) of stellar nucleosynthesis. We performed a detailed analysis of the high-resolution and high signal-to-noise ratio near-UV spectra from the archive of HIRES on the Keck telescope, UVES on the VLT, and HDS on the Subaru Telescope, to determine the Pd and Ag abundances of 95 stars. This sample covers a wide metallicity range with -2.6 $\lesssim$ [Fe/H] $\lesssim$ +0.1, and most of them are dwarfs. The plane-parallel LTE MAFAGS-OS model atmosphere was adopted, and the spectral synthesis method was used to derive the Pd and Ag abundances from Pd I {\lambda} 3404 {\AA} and Ag I {\lambda} 3280/3382 {\AA} lines. We found that both elements are enhanced in metal-poor stars, and their ratios to iron show flat trends at -0.6 < [Fe/H] < +0.1. The abundance ratios of [Ag/H] and [Pd/H] are well correlated over the whole abundance range. This implies that Pd and Ag have similar formation mechanisms during the Galactic evolution.Comment: 15 pages, 12 figures, accepted to A&

Superdensity Operators for Spacetime Quantum Mechanics

We introduce superdensity operators as a tool for analyzing quantum information in spacetime. Superdensity operators encode spacetime correlation functions in an operator framework, and support a natural generalization of Hilbert space techniques and Dirac's transformation theory as traditionally applied to standard density operators. Superdensity operators can be measured experimentally, but accessing their full content requires novel procedures. We demonstrate these statements on several examples. The superdensity formalism suggests useful definitions of spacetime entropies and spacetime quantum channels. For example, we show that the von Neumann entropy of a superdensity operator is related to a quantum generalization of the Kolmogorov-Sinai entropy, and compute this for a many-body system. We also suggest experimental protocols for measuring spacetime entropies.Comment: 43+16 pages, 12 figures; v2: typos fixed, references adde

Synthesis of empty bacterial microcompartments, directed organelle protein incorporation, and evidence of filament-associated organelle movement

Compartmentalization is an important process, since it allows the segregation of metabolic activities and, in the era of synthetic biology, represents an important tool by which defined microenvironments can be created for specific metabolic functions. Indeed, some bacteria make specialized proteinaceous metabolic compartments called bacterial microcompartments (BMCs) or metabolosomes. Here we demonstrate that the shell of the metabolosome (representing an empty BMC) can be produced within E. coil cells by the coordinated expression of genes encoding structural proteins. A plethora of diverse structures can be generated by changing the expression profile of these genes, including the formation of large axial filaments that interfere with septation. Fusing GFP to PduC, PduD, or PduV, none of which are shell proteins, allows regiospecific targeting of the reporter group to the empty BMC. Live cell imaging provides unexpected evidence of filament-associated BMC movement within the cell in the presence of Pdu

The X-ray quiescence of Swift J195509.6+261406 (GRB 070610): an optical bursting X-ray binary?

We report on a 63ks Chandra observation of the X-ray transient Swift J195509.6+261406 discovered as the afterglow of what was first believed to be a long duration Gamma-Ray Burst (GRB 070610). The outburst of this source was characterized by unique optical flares on timescales of second or less, morphologically similar to the short X-ray bursts usually observed from magnetars. Our Chandra observation was performed ~2 years after the discovery of the optical and X-ray flaring activity of this source, catching it in its quiescent state. We derive stringent upper limits on the quiescent emission of Swif J195509.6+261406 which argues against the possibility of this object being a typical magnetar. Our limits show that the most viable interpretation on the nature of this peculiar bursting source, is a binary system hosting a black hole or a neutron star with a low mass companion star (< 0.12 M_{\odot}), and with an orbital period smaller than a few hours.Comment: 5 pages, 3 figures, accepted for publication in ApJ Letter

Adopting the Brisoux-Larouche Model of Brand Categorization to Correlate Brand Social Responsibility in National and In-house Coffee Shops

Abstract In-house food service brands operating on college campuses struggle to build brand image without consumer awareness. Corporate Social Responsibility (CSR) activities may enhance brand image, for the customers, employees and stakeholders (Lee and Heo, 2009). Brown and Dacin (1997) suggested that CSR associations have significant influence on consumer’s response to new products. The objective of the study is to determine if brand social responsibility influences customers’ purchase decisions and how they cognitively categorize brands. The quantitative methodology involves two different survey instruments designed to be interpreted using Structured Equation Modeling (SEM) and regression analysis. The study confirms that a in house coffee brand offering a high quality product, deploying a brand social responsible strategy can be coveted by the college campus customer with little or no previous experience of the brand