Validation of the Ambassador Questionnaire for Undergraduate Students Conducting Engineering Outreach

Although K-12 engineering outreach commonly involves college students, the young professionals who act as ambassadors for their field are less likely to be studied than the students they serve. Yet, outreach activities may offer opportunities for undergraduate students to develop aspects of their professional selves. As there is currently no comprehensive measure that allows researchers, program evaluators, and outreach advisors to examine ambassadors\u27 professional development and growth, this study sought to develop and validate an Ambassador Questionnaire (AQ). The multi-step process included the selection and adaptation of items from extant measures of engineering students\u27 motivation, beliefs, professional skills, and perceptions of ambassador training. After an expert panel evaluated the initial group of items, the 57-item AQ was completed by a diverse group of 350 undergraduate engineering students engaged in ambassadorship. Exploratory and confirmatory factor analyses were used to examine construct validity, and internal consistency reliability analyses followed. The findings indicated a five-factor model that accounted for 53% of the variance and demonstrated strong internal consistency reliability. Potential uses for the measure are discussed

S-, P- and D-wave resonances in positronium-sodium and positronium-potassium scattering

Scattering of positronium (Ps) by sodium and potassium atoms has been investigated employing a three-Ps-state coupled-channel model with Ps(1s,2s,2p) states using a time-reversal-symmetric regularized electron-exchange model potential fitted to reproduce accurate theoretical results for PsNa and PsK binding energies. We find a narrow S-wave singlet resonance at 4.58 eV of width 0.002 eV in the Ps-Na system and at 4.77 eV of width 0.003 eV in the Ps-K system. Singlet P-wave resonances in both systems are found at 5.07 eV of width 0.3 eV. Singlet D-wave structures are found at 5.3 eV in both systems. We also report results for elastic and Ps-excitation cross sections for Ps scattering by Na and K.Comment: 9 pages, 5 figures, Accepted in Journal of Physics

Convergent variational calculation of positronium-hydrogen-atom scattering lengths

We present a convergent variational basis-set calculational scheme for elastic scattering of positronium atom by hydrogen atom in S wave. Highly correlated trial functions with appropriate symmetry are needed for achieving convergence. We report convergent results for scattering lengths in atomic units for both singlet ($=3.49\pm 0.20$) and triplet ($=2.46\pm 0.10$) states.Comment: 11 pages, 1 postscript figure, Accepted in J. Phys. B (Letter

Conductivity in Jurkat cell suspension after ultrashort electric pulsing

Ultrashort electric pulses applied to similar cell lines such as Jurkat and HL-60 cells can produce markedly different results , which have been documented extensively over the last few years. We now report changes in electrical conductivity of Jurkat cells subjected to traditional electroporation pulses (50 ms pulse length) and ultrashort pulses (10 ns pulse length) using time domain dielectric spectroscopy (TDS). A single 10 ns, 150 kV/cm pulse did not noticeably alter suspension conductivity while a 50 ms, 2.12 kV/cm pulse with the same energy caused an appreciable conductivity rise. These results support the hypothesis that electroporation pulses primarily interact with the cell membrane and cause conductivity rises due to ion transport from the cell to the external media, while pulses with nanosecond duration primarily interact with the membranes of intracellular organelles. However, multiple ultrashort pulses have a cumulative effect on the plasma membrane, with five pulses causing a gradual rise in conductivity up to ten minutes post-pulsing

Nanosecond electric pulses penetrate the nucleus and enhance speckle formation

Nanosecond electric pulses generate nanopores in the interior membranes of cells and modulate cellular functions. Here, we used confocal microscopy and flow cytometry to observe Smith antigen antibody (Y12) binding to nuclear speckles, known as small nuclear ribonucleoprotein particles (snRNPs) or intrachromatin granule clusters (IGCs), in Jurkat cells following one or five 10 ns, 150 kV/cm pulses. Using confocal microscopy and flow cytometry, we observed changes in nuclear speckle labeling that suggested a disruption of pre-messenger RNA splicing mechanisms. Pulse exposure increased the nuclear speckled substructures by 2.5-fold above basal levels while the propidium iodide (PI) uptake in pulsed cells was unchanged. The resulting nuclear speckle changes were also cell cycle dependent. These findings suggest that 10 ns pulses directly influenced nuclear processes, such as the changes in the nuclear RNA–protein complexes

Resilience-Focused HIV Care to Promote Psychological Well-Being During COVID-19 and Other Catastrophes

The COVID-19 pandemic has adversely affected people with HIV due to disruptions in prevention and care services, economic impacts, and social isolation. These stressors have contributed to worse physical health, HIV treatment outcomes, and psychological wellness. Psychological sequelae associated with COVID-19 threaten the overall well-being of people with HIV and efforts to end the HIV epidemic. Resilience is a known mediator of health disparities and can improve psychological wellness and behavioral health outcomes along the HIV Continuum of Care. Though resilience is often organically developed in individuals as a result of overcoming adversity, it may be fostered through multi-level internal and external resourcing (at psychological, interpersonal, spiritual, and community/neighborhood levels). In this Perspective, resilience-focused HIV care is defined as a model of care in which providers promote optimum health for people with HIV by facilitating multi-level resourcing to buffer the effects of adversity and foster well-being. Adoption of resilience-focused HIV care may help providers better promote well-being among people living with HIV during this time of increased psychological stress and help prepare systems of care for future catastrophes. Informed by the literature, we constructed a set of core principles and considerations for successful adoption and sustainability of resilience-focused HIV care. Our definition of resilience-focused HIV care marks a novel contribution to the knowledge base and responds to the call for a multidimensional definition of resilience as part of HIV research

Low-energy quenching of positronium by helium

Very low-energy scattering of orthopositronium by helium has been investigated for simultaneous study of elastic cross section and pick-off quenching rate using a model exchange potential. The present calculational scheme, while agrees with the measured cross section of Skalsey et al, reproduces successfully the parameter ^ 1Z_{\makebox{eff}}, the effective number of electrons per atom in a singlet state relative to the positron. Together with the fact that this model potential also leads to an agreement with measured medium energy cross sections of this system, this study seems to resolve the long-standing discrepancy at low energies among different theoretical calculations and experimental measurements.Comment: 4 latex pages, 3 postscript figure

Evaluation of a library of FDA-approved drugs for their ability to potentiate antibiotics against multidrug resistant Gram-negative pathogens

The Prestwick library was screened for antibacterial activity or 'antibiotic-resistance breaking' (ARB) potential against four species of Gram-negative pathogens. Discounting known antibacterials, the screen identified very few ARB hits, which were strain/drug specific. These ARB hits included antimetabolites (zidovudine, floxuridine, didanosine, gemcitabine), anthracyclines (daunorubicin, mitoxantrone, epirubicin) and psychoactive drugs (gabapentin, fluspirilene, oxethazaine). This suggests that there are few approved drugs which could be directly repositioned as adjunct-antibacterials and these will need robust testing to validate efficacy. [Abstract copyright: © Crown copyright 2019.

Electron exchange model potential: Application to positronium-helium scattering

The formulation of a suitable nonlocal model potential for electron exchange is presented, checked with electron-hydrogen and electron-helium scattering, and applied to the study of elastic and inelastic scattering and ionization of ortho positronium (Ps) by helium. The elastic scattering and the $n = 2$ excitations of Ps are investigated using a three-Ps-state close-coupling approximation. The higher ($n\ge 3$) excitations and ionization of Ps atom are treated in the framework of Born approximation with present exchange. Calculations are reported of phase shifts, and elastic, Ps-excitation, and total cross sections. The present target elastic total cross section agrees well with experimental results at thermal to medium energies.Comment: 16 latex pages, 7 postscript figure

Mechanisms of retinal ganglion cell injury following acute increases in intraocular pressure

The maintenance of intraocular pressure (IOP) is critical to preserving the pristine optics required for vision. Disturbances in IOP can directly impact the optic nerve and retina, and inner retinal injury can occur following acute and chronic IOP elevation. There are a variety of animal models that have been developed to study the effects of acute and chronic elevation of IOP on the retina, retinal ganglion cell (RGC) morphology, intracellular signaling, gene expression changes, and survival. Acute IOP models induce injury that allows for the study of RGC response to well characterized injury and potential recovery. This review will focus on the initial impact of acute IOP elevation on RGC injury and recovery as these early responses may be the best targets for potential therapeutic interventions to promote RGC survival in glaucoma