Preterm infants have deficient monocyte and lymphocyte cytokine responses to Group B Streptococcus

Group B streptococcus GBS) is an important cause of early-and late-onset sepsis in the newborn. Preterm infants have markedly increased susceptibility and worse outcomes, but their immunological responses to GBS are poorly defined. We compared mononuclear cell and whole-blood cytokine responses to heat-killed GBS HKGBS) of preterm infants gestational age [GA], 26 to 33 weeks), term infants, and healthy adults. We investigated the kinetics and cell source of induced cytokines and quantified HKGBS phagocytosis. HKGBS-induced tumor necrosis factor TNF) and interleukin 6 (IL-6) secretion was significantly impaired in preterm infants compared to that in term infants and adults. These cytokines were predominantly monocytic in origin, and production was intrinsically linked to HKGBS phagocytosis. Very preterm infants GA, < 30 weeks) had fewer cytokine-producing monocytes, but nonopsonic phagocytosis ability was comparable to that for term infants and adults. Exogenous complement supplementation increased phagocytosis in all groups, as well as the proportion of preterm monocytes producing IL-6, but for very preterm infants, responses were still deficient. Similar defective preterm monocyte responses were observed in fresh whole cord blood stimulated with live GBS. Lymphocyte-associated cytokines were significantly deficient for both preterm and term infants compared to levels for adults. These findings indicate that a subset of preterm monocytes do not respond to GBS, a defect compounded by generalized weaker lymphocyte responses in newborns. Together these deficient responses may increase the susceptibility of preterm infants to GBS infection

Deepening the Universal Apostolic Preferences through Discernment at Xavier University

Following Fr. Arturo Sosa, S.J.’s promulgation of the Universal Apostolic Preferences (UAPs) and as part of Xavier University’s strategic planning, the Center for Mission and Identity invited faculty and staff to participate in a semester-long Discernment Group to learn about each of the UAPs and to brainstorm ways to deepen Xavier’s expression of each, resulting in a strategic proposal (one of the President\u27s Annual Goals). Based on the principles of Ignatian Communal Discernment, the Discernment Group met throughout the Fall 2019 semester in prayerful discussion and reflection and produced documents for each of the UAPs, which were then shared and vetted by the university community. The Discernment Group concluded with the creation of a document outline Xavier’s current best practices, next steps, and aspirational goals. The work of integrating the UAPs into the life of the Xavier University is an on-going effort, which is now guided by the document – a strategic plan for the decade. This discernment process may be effective for other Jesuit Catholic institutions seeking methods to advance the UAPs

Transport across a carbon nanotube quantum dot contacted with ferromagnetic leads: experiment and non-perturbative modeling

We present measurements of tunneling magneto-resistance (TMR) in single-wall carbon nanotubes attached to ferromagnetic contacts in the Coulomb blockade regime. Strong variations of the TMR with gate voltage over a range of four conductance resonances, including a peculiar double-dip signature, are observed. The data is compared to calculations in the "dressed second order" (DSO) framework. In this non-perturbative theory, conductance peak positions and linewidths are affected by charge fluctuations incorporating the properties of the carbon nanotube quantum dot and the ferromagnetic leads. The theory is able to qualitatively reproduce the experimental data.Comment: 14 pages, 13 figure

Universality of the Kondo effect in quantum dots with ferromagnetic leads

We investigate quantum dots in clean single-wall carbon nanotubes with ferromagnetic PdNi-leads in the Kondo regime. In most odd Coulomb valleys the Kondo resonance exhibits a pronounced splitting, which depends on the tunnel coupling to the leads and an external magnetic field $B$, and only weakly on gate voltage. Using numerical renormalization group calculations, we demonstrate that all salient features of the data can be understood using a simple model for the magnetic properties of the leads. The magnetoconductance at zero bias and low temperature depends in a universal way on $g \mu_B (B-B_c) / k_B T_K$, where $T_K$ is the Kondo temperature and $B_c$ the external field compensating the splitting.Comment: 4 pages, 4 figure

Liquid-induced damping of mechanical feedback effects in single electron tunneling through a suspended carbon nanotube

In single electron tunneling through clean, suspended carbon nanotube devices at low temperature, distinct switching phenomena have regularly been observed. These can be explained via strong interaction of single electron tunneling and vibrational motion of the nanotube. We present measurements on a highly stable nanotube device, subsequently recorded in the vacuum chamber of a dilution refrigerator and immersed in the 3He/4He mixture of a second dilution refrigerator. The switching phenomena are absent when the sample is kept in the viscous liquid, additionally supporting the interpretation of dc-driven vibration. Transport measurements in liquid helium can thus be used for finite bias spectroscopy where otherwise the mechanical effects would dominate the current.Comment: 4 pages, 3 figure

Negative frequency tuning of a carbon nanotube nano-electromechanical resonator

A suspended, doubly clamped single wall carbon nanotube is characterized as driven nano-electromechanical resonator at cryogenic temperatures. Electronically, the carbon nanotube displays small bandgap behaviour with Coulomb blockade oscillations in electron conduction and transparent contacts in hole conduction. We observe the driven mechanical resonance in dc-transport, including multiple higher harmonic responses. The data shows a distinct negative frequency tuning at finite applied gate voltage, enabling us to electrostatically decrease the resonance frequency to 75% of its maximum value. This is consistently explained via electrostatic softening of the mechanical mode.Comment: 4 pages, 4 figures; submitted for the IWEPNM 2013 conference proceeding

Normal metal - insulator - superconductor interferometer

Hybrid normal metal - insulator - superconductor microstructures suitable for studying an interference of electrons were fabricated. The structures consist of a superconducting loop connected to a normal metal electrode through a tunnel barrier . An optical interferometer with a beam splitter can be considered as a classical analogue for this system. All measurements were performed at temperatures well below 1 K. The interference can be observed as periodic oscillations of the tunnel current (voltage) through the junction at fixed bias voltage (current) as a function of a perpendicular magnetic field. The magnitude of the oscillations depends on the bias point. It reaches a maximum at energy $eV$ which is close to the superconducting gap and decreases with an increase of temperature. Surprisingly, the period of the oscillations in units of magnetic flux $\Delta \Phi$ is equal neither to $h/e$ nor to $h/2e$, but significantly exceeds these values for larger loop circumferences. The origin of the phenomena is not clear.Comment: 11 pages and 8 figure

Sub-gap spectroscopy of thermally excited quasiparticles in a Nb contacted carbon nanotube quantum dot

We present electronic transport measurements of a single wall carbon nanotube quantum dot coupled to Nb superconducting contacts. For temperatures comparable to the superconducting gap peculiar transport features are observed inside the Coulomb blockade and superconducting energy gap regions. The observed temperature dependence can be explained in terms of sequential tunneling processes involving thermally excited quasiparticles. In particular, these new channels give rise to two unusual conductance peaks at zero bias in the vicinity of the charge degeneracy point and allow to determine the degeneracy of the ground states involved in transport. The measurements are in good agreement with model calculations.Comment: 5 pages, 4 figure

Investigating a new model of time-related academic behavior: Procrastination and timely engagement by motivational orientation

Scope and Method of Study: The purpose of this study was to examine the nature of time-related academic behavior (i.e., procrastination and timely engagement) in the academic context. Specifically, this study aimed to build a new model for understanding these behaviors in a motivational framework by using motivational orientation to frame these behaviors. Participants were 1,227 undergraduate students enrolled in face-to-face courses at a large Midwestern university. Each participant completed a series of measures including the 2x2 Measure of Procrastination and Timely Engagement, two subscales of the Motivated Strategies for Learning Questionnaire, the Achievement Goal Questionnaire, a measure of Self-Efficacy for Self-Regulation, the mini-IPIP, and a demographic questionnaire through an online survey, and participants completed the same measures again 15 weeks later.Findings and Conclusions: Findings include confirmatory factor analyses for all key measures. These indicated the four-factor model for time-related academic behavior was the best-fitting model to the observed data. Further, these raised questions about the existing models of achievement goals. Reliability analyses were also performed in three different models including the traditional tau-equivalent model (Chronbach's alpha), the congeneric model, and the test-retest model. Then, structural equation modeling was conducted to determine how well the variables would predict time-related academic behavior. Then, these models were retested using path analysis on the longitudinal data to determine how well this prediction holds up across time. Finally, cluster analysis was used for a person-centered view of the nature of the relationships among the variables. The findings present the view that self-efficacy for self-regulation may be one of the more important predictors of time-related academic behavior, that time-related academic behaviors seem to be related to the goals one has for the situation, and that personality is not a strong predictor across time, suggesting these behaviors are more malleable to intervention than previously thought. Implications for educational practice, theory, and future research are discussed