Hybridization and enhancement processes in quasi-two dimensional superconductors

Superconductivity is a field with a great many branches and applications. In this dissertation, we focus on two specific processes in superconductors -- light-induced enhancement and hybridization of collective modes -- in two types of quasi-two dimensional materials -- either the loosely coupled planes of a layered superconductor or a superconducting thin film. Motivated by experiments in the cuprates that have seen evidence of a transient superconducting state upon optical excitation we study the effects of inter-plane tunneling on the competition between superconductivity and charge order. We find that an optical pump can suppress the charge order and simultaneously enhance superconductivity, due to the inherent competition between the two. Taking into account that the charge order empirically shows a broad peak in c-axis momentum, we consider a model of randomly oriented charge ordering domains and study how interlayer coupling affects the competition of this order with superconductivity. Also in the cuprates, several groups have reported observations of collective modes of the charge order present in underdoped cuprates. Motivated by these experiments, we study theoretically the oscillations of the order parameters, both in the case of pure charge order, and for charge order coexisting with superconductivity. Using a hot-spot approximation we find in the coexistence regime two Higgs modes arising from hybridization of the amplitude oscillations of the different order parameters. We explore the damping channels of these hybrid modes. As another means of enhancing superconductivity we consider coupling a two-dimensional superconducting film to the quantized electromagnetic modes of a microwave resonator cavity. We find that when the photon and quasiparticle systems are out of thermal equilibrium, a redistribution of quasiparticles into a more favorable non-equilibrium steady-state occurs, thereby enhancing superconductivity in the sample, a fluctuation analog of a phenomenon known as the Eliashberg effect. Finally, following the recent success of realizing exciton-polariton condensates in cavities, we examine the hybridization of cavity photons with two types of collective modes in superconductors. Enabled by the recently predicted and observed supercurrent-induced linear coupling between these excitations and light, we find that significant hybridization between the superconductor's collective modes and resonant cavity photons can occur

An assessment of equilibrium in the Merensky Reef : a textural, geochemical and Nd isotope study of coexisting plagioclase and orthopyroxene from Winnaarshoek in the eastern Bushveld Complex, RSA

Evidence of mineral disequilibrium is presented for the Merensky Reef at Winnaarshoek in the eastern Bushveld Complex. Petrographic disequilibrium textures, disequilibrium in orthopyroxene, plagioclase and clinopyroxene mineral compositions as well as disequilibrium in Sm-Nd isotopic compositions of whole rock samples and coexisting plagioclase and orthopyroxene are presented. Disequilibrium textures presented include clinopyroxene exsolution lamellae in orthopyroxene; resorbed plagioclase in orthopyroxene or relict plagioclase; various inclusions such as orthopyroxene, plagioclase or clinopyroxene in larger oikocrysts of clinopyroxene or orthopyroxene; discontinuous rims of clinopyroxene surrounding orthopyroxene; resorbed orthopyroxene in clinopyroxene; and corona textures associated with olivine. These textures were used to derive a possible mineral crystallization sequence. At least two sequences of crystallization took place, both of which crystallized plagioclase first. One sequence then crystallized olivine which was then consumed to produce orthopyroxene which crystallized prior to late clinopyroxene. The other sequence indicates orthopyroxene crystallization after plagioclase crystallization, followed by crystallization of clinopyroxene. These sequences indicate at least two magmas were responsible for the genesis of the Merensky Reef and its hanging wall and footwall units. Compositionally, disequilibrium is evident in the range of compositions found in coexisting orthopyroxene, plagioclase and clinopyroxene with stratigraphic height, with particular reference to the change in mineral composition in each of the hanging wall, Reef and footwall units. Orthopyroxene compositions range in Mg numbers between 74.6 and 82.9 (77.4) in the hanging wall, 78.5 and 87.0 (avg. 81.1) in the Reef, and 77.9 and 84.1 (avg. 81.3) in the footwall. Plagioclase compositions range in An content between An64.9 and An82.3 (avg. An75.1) in the hanging wall, An56.8 to An70.8 (avg. An62.7) in the Reef, and An54.2 to An86.3 (avg. An73.2) in the footwall. In terms of Sm-Nd isotopic compositions, disequilibrium is evident between both whole rock samples and coexisting plagioclase and orthopyroxenes. Bulk rock Sm-Nd isotopic compositions show a range in ԐNd values between ԐNd (2.06 Ga) = -4.8 to -6.4 in the hangingwall, ԐNd (2.06 Ga) = -6.3 to -8.5 in the Reef, and ԐNd (2.06 Ga) = -4.5 to -6.3 in the footwall. Similar ԐNd values are present in the hanging wall and footwall units, with a clear “spike” in the Merensky Reef. ԐNd values in plagioclase are between ԐNd (2.06 Ga) = -5.8 and -7.8, while orthopyroxene isotopic Sm-Nd values are between ԐNd (2.06 Ga = -7.1 and -9.1. The mineral disequilibrium features presented within this study help elucidate the crystallization sequence of the magma as well as to constrain the contamination of the magma upon ascension and emplacement of the Merensky Reef. The results of this study favour a model where a mantle plume resulted in the ascent of a new magma which was contaminated by the assimilation of old, lower crust. Contamination took place prior to the possible lateral emplacement of the Merensky reef as a density current. 5-10% contamination of depleted mantle or a B2-“like” source by Archaean TTGs is modeled to achieve the contamination “spike” of ԐNd = -8.5 in the Merensky Reef

STEAM on the Quad

STEAM on the Quad is a family-oriented educational program, initiated in 2016, involving K-12 youth. Participants are able to do hands-on activities that improve their knowledge and interest in the science, technology, engineering, arts and math fields. The event is a collaborative project between Ohio State – Lima and OSU Extension. The 4-H programs of Putnam, Hardin and Allen counties hosted activities that featured Bluetooth sports, circuitry, Lego zip lines, virtual reality, graphics tablets, solar panels, sculpture building, hovercrafts and sewing. Community partners included the Allen County Soil and Water Conservation District, ArtSpace/Lima, YWCA Child Care, the Neil Armstrong Museum, and the Lima YMCA Bean City Bots Robotics Team. Ohio State – Lima faculty from biology, education, engineering, geology, and theater engaged K-12 students and their families in a variety of hands-on projects, as did Ohio State law enforcement. Ohio State staff and students aided in these endeavors and in logistical support. Outcomes and Impacts: 1) Connect local families, faculty, educators, and businesses to promote STEAM education through innovation, learning, and creativity in collaboration with Ohio State. 2) Take Ohio State's current resources and equipment and create programming that reaches new audiences, while bringing local 4-H members to an Ohio State campus. 3) Create a program model that can be reproduced by Extension in Ohio and other states. Outcomes and impacts will consist of recording the attendance and partnerships created through the STEAM programming, categorized by age group, program area, and type of use. Each student will complete a retrospective pre- and post-survey to see if our key STEM metrics are met. Finally, program evaluations will illustrate usage by parents and will collect open-ended feedback about how the STEAM programming has benefited their child. Quarterly progress reports will be provided to the university.AUTHOR AFFILIATION: Kelly Coble, Educator, 4-H Youth Development, The Ohio State University Extension, Allen County, [email protected] (Corresponding Author); Jason Hedrick, Educator, 4-H Youth Development, The Ohio State University Extension, Putnam County; Mark Light, Educator, 4-H Youth Development, The Ohio State University Extension, Hardin County; Amanda Raines, Program Assistant, 4-H Youth Development, The Ohio State University Extension, Hardin County; Sarah Jackson, Program Assistant, 4-H Youth Development, The Ohio State University Extension, Allen County.STEAM on the Quad is a family-oriented educational program, initiated in 2016, involving K-12 youth. Participants did hands-on activities that improved their knowledge and interest in the science, technology, engineering, arts and math fields. The event is a collaborative project between Ohio State – Lima and OSU Extension. The 4-H programs of Putnam, Hardin and Allen counties hosted activities that featured Bluetooth sports, Lego zip lines, virtual reality, graphics tablets, solar panels, sculpture building, hovercrafts and sewing. Community partners included the Allen County Soil and Water Conservation District, ArtSpace/Lima, YWCA Child Care, the Neil Armstrong Museum, and the Lima YMCA Bean City Bots robotics team. Ohio State – Lima faculty from biology, education, engineering, and theater engaged K-12 students and their families in a variety of hands-on projects, as did Ohio State law enforcement. Ohio State staff and students aided in these actvities and logistical support

Nurr1 dependent regulation of pro-inflammatory mediators in immortalised synovial fibroblasts

BACKGROUND: Nurr1 is an orphan member of the nuclear receptor superfamily; these orphan receptors are a group for which a ligand has yet to be identified. Nurr1 has been shown to regulate the expression of a small number of genes as a monomeric, constitutively active receptor. These Nurr1 regulated genes are primarily associated with dopamine cell maturation and survival. However, previous reports have shown an increased expression of Nurr1 in the synovium of patients with rheumatoid arthritis (RA) suggesting a pro-inflammatory role for Nurr1 in RA. In this study we investigate the potential pro-inflammatory role of Nurr1 by monitoring Nurr1 dependent gene expression in an immortalised synoviocyte cell line, K4IM. METHODS: We overexpressed the wild type and a dominant negative form of the orphan nuclear receptor Nurr1, in a model synoviocyte cell line. Using the Affymetrix HG-U133 Genechips we demonstrate the effects on the transcriptome by the receptor. Further evidence of gene expression change was demonstrated using quantitative RT-PCR and ELISA analysis. RESULTS: We show that Nurr1 regulates transcription of a small number of genes for pro-inflammatory modulators of which the most significant is interleukin-8 (IL-8). We also demonstrate increased synthesis and secretion of IL-8 further supporting a role for Nurr1 in inflammatory signalling pathways. CONCLUSION: Using microarray analysis we show that elevated levels of Nurr1 leads to increased gene expression of pro-inflammatory genes: IL-8, Amphiregulin and Kit ligand in a model cell line. This data provides further evidence for an additional role for Nurr1 in inflammation and may play a role in the pathogenesis of rheumatoid arthritis

Radiation Tolerance of Low-Cost Magnetometer for Space Applications

Knowing the three-dimensional magnetic field configuration and dynamics in space environments is key to understand the physical processes taking place. Plasma dynamics depend on the local orientation of the magnetic field, and key quantities such as pitch angle and dynamical processes such as waves and reconnection cannot be studied without in-situ measurements of the fields. For this reason, magnetometers are one of the most important instruments for space physics-focused missions. This is true both for spacecraft and also for landed missions, particularly on atmosphere-less bodies, where the space environment interacts directly with the surface. To enable the next generation of small spacecraft and landers, sensors need to be low-cost and withstand the harsh radiation environment present in space. Here we present the latest advances in the characterization of a commercial-off-the-shelf three-dimensional magnetometer,summarizing previous and newresults from radiation tests. The sensor shows tolerance up to a total ionization dose (TID) of 300 krad, levels well beyond those typical for a low-Earth orbit mission, and compliant with those expected during a landed mission on the Jovian moon Europa

Carbon Nitride as a Ligand: Selective Hydrogenation of Terminal Alkenes using [(η5-C5Me5)IrCl(g-C3N4-κ2N, N')]Cl : Selective Hydrogenation of Terminal Alkenes using [(η5-C5Me5)IrCl(g-C3N4-κ2N, N')]Cl

Anchoring a homogeneous catalyst onto a heterogeneous support facilitates separation of the product from the catalyst, and catalyst-substrate interactions can also modify reactivity. Herein we describe the synthesis of composite materials comprising carbon nitride (g-C 3 N 4 ) as the heterogeneous support and the well established homogeneous catalyst moiety [Cp*IrCl] + (where Cp* = η 5 -C 5 Me 5 ), commonly used for catalytic hydrogenation. Coordination of [Cp*IrCl] + to g-C 3 N 4 occurs directly at exposed edge sites with a κ 2 N, N' binding motif, leading to a primary inner coordination sphere analogous to known homogeneous complexes of the general class [Cp*IrCl(NN-κ 2 N, N' )] + (where N, N' = a bidentate nitrogen ligand). Hydrogenation of unsaturated substrates using the composite catalyst is selective for terminal alkenes, which is attributed to the restricted steric environment of the outer coordination sphere at the edge-sites of g-C 3 N 4

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362