Induced hypothermia post cardiac resuscitation works in hospitalized patients but not during transport to hospital, a logical inconsistency of evidence

A critical appraisal and clinical application of Kim F, Nichol G, Maynard C, et al. Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest. JAMA 2013;311(1):45-52. doi:10.1001/jama.2013.28217

Strains and polarization developed during electric field-induced antiferroelectric to ferroelectric phase transformations in lead zirconate-based ceramics

Widespread adoption of renewable energy sources, such as wind and solar power, will necessitate an efficient way to interface with energy storage devices in order to ensure around-the-clock energy delivery during off-peak hours. Energy storage devices implementing linear dielectric capacitors offer exceptional power density (i.e. rate of charge/discharge), but cannot match the energy density (i.e. storage capacity) of batteries. However, replacing the linear dielectric in capacitors with an antiferroelectric material has the potential to increase the energy density by approximately one order of magnitude. Since the energy is stored via a reversible and diffusionless antiferroelectric-to-ferroelectric phase transformation, the high power density is maintained. In this study, the response of antiferroelectric Pb0.99Nb0.02[(Zr0.57Sn0.43)1-yTiy]0.98O3 ceramics with compositions near an antiferroelectric/ferroelectric phase boundary were systemically characterized in the presence of electric fields. By altering the titanium content (y in the chemical formula) the phase boundary was incrementally approached, allowing for detailed study of the electric field-induced phase transformation in this region of structural instability. The key parameters of polarization, longitudinal strain, and transverse strain were simultaneously recorded as a function of externally applied electric fields on all compositions. It was found that the volume expansion and polarization developed during the antiferroelectric-to-ferroelectric phase transformation remained ~0.4% and ~30 μC/cm2, respectively, regardless of the composition in the range of 0.060 ≤ y ≤ 0.075. However, the critical field strengths associated with the phase transformation varied in a linear fashion with y, supporting the suggestion that increasing the titanium content strengthens the ferroelectric ordering of the system. Application of axial and radial compressive pre-stresses to samples with composition y = 0.060 were observed to increase the critical field magnitude necessary to induce the ferroelectric phase, but the manners in which they suppressed the phase transformation were distinctively different. Axial pre-stresses resulted in an abrupt, uniform suppression while radial pre-stresses caused a gradual, non-uniform suppression of the phase transformation. The results were interpreted based on different textures in the ceramic developed by each pre-stress condition. In the absence of mechanical confinement, the induced ferroelectric phase in compositions y ≥ 0.069 became metastable and the ferroelectric-to-antiferroelectric phase transformation did not occur during the unloading of the applied field. This reverse phase transformation occurred partially when electric fields with reversed polarity were applied, though the extent of the antiferroelectric phase recovered diminished with increasing titanium content. Through the use of in-situ X-ray diffraction, an electric field-induced ferroelectric-to-antiferroelectric phase transformation was confirmed for the first time

Investigating Linguistic, Literary, and Social Affordances of L2 Collaborative Reading

This exploratory study analyzes learner–learner interactions within a virtual environment when collaboratively reading Spanish poetry in a Hispanic literature course at the college level via an ecological theoretical perspective (van Lier, 2004). The goals of the study are (a) to present empirical data that illustrate the theoretical construct of affordance in a virtual, collaborative reading environment, and (b) to investigate the pedagogical ramifications of using a digital annotation tool to involve learners in collaborative reading. Three distinct types of affordances emerged in the data: linguistic, literary, and social affordances. Our findings indicate that the number of literary and social affordances outnumbered the linguistic affordances that emerged in students’ threaded discussions while collaboratively reading and annotating poems. In addition, the primary challenges for learners when engaging in collaborative reading included others’ comments impeding some students’ understanding of the text, and having to make one’s comments distinct from others’ comments to avoid being socially viewed as an inactive reader or student. From a pedagogical perspective, the primary benefits of incorporating collaborative reading in a second language poetry course involve the ability to establish a more open learning community and allowing students to carry out a closer reading of literary texts

Centering the Marginalized: The Impact of the Pandemic on Online Student Retention

During the pandemic, much of the focus of administrators and scholars has been on its impact on residential students and the sudden shift to online instruction. While justified, researchers have yet to focus on online students—who often represent marginalized communities in higher education—to ask whether they were impacted by factors related to the pandemic other than the modality shift. In this study, we examined how the first-year retention of online students was affected during the pandemic, and whether it differed from first-year residential students who transitioned online. We examined records of two student cohorts (Fall 2017 and Fall 2019) from a university to determine each cohort’s retention rate by modality. Holding other relevant factors constant, we found the COVID cohort of students were less likely to persist to the following Fall regardless of modality, although residential students were still much more likely to be retained overall. However, Black and Hispanic students were less likely to be retained across both modalities, and even Black residential students were more vulnerable to not returning than their White counterparts, suggesting that racial inequalities persist across learning modalities. We conclude by suggesting how one retention tool—financial aid—could be used to address the particular needs of online students to improve their retention

Hydrostatic pressure study of single-crystalline UNi0.5Sb2

We studied single-crystals of the antiferromagnetic compound UNi0.5Sb2 (TN ~ 161 K) by means of measurements of magnetic susceptibility (chi), specific heat (Cp), and electrical resistivity (rho) at ambient pressure, and resistivity under hydrostatic pressures up to 20 kbar, in the temperature range from 1.9 to 300 K. The thermal coefficient of the electrical resistivity (drho/dT) changes drastically from positive below TN to negative above, reflecting the loss of spin-disorder scattering in the ordered phase. Two small features in the rho vs T data centered near 40 and 85 K correlate well in temperature with features in the magnetic susceptibility and are consistent with other data in the literature. These features are quite hysteretic in temperature, i.e., the difference between the warming and cooling cycles are about 10 and 6 K, respectively. The effect of pressure is to raise TN at the approximate rate of 0.76 K/kbar, while progressively suppressing the amplitude of the small features in rho vs T at lower temperatures and increasing the thermal hysteresis.Comment: 9 pages, 3 figues, 2007-mmm conferenc

Integrated Models of Care for Individuals with Opioid Use Disorder: How Do We Prevent HIV and HCV?

Purpose of Review To describe models of integrated and co-located care for opioid use disorder (OUD), hepatitis C (HCV), and HIV. Recent Findings The design and scale-up of multidisciplinary care models that engage, retain, and treat individuals with HIV, HCV, and OUD are critical to preventing continued spread of HIV and HCV. We identified 17 models within primary care (N = 3), HIV specialty care (N = 5), opioid treatment programs (N = 6), transitional clinics (N = 2), and community-based harm reduction programs (N = 1), as well as two emerging models. Summary Key components of such models are the provision of (1) medication-assisted treatment for OUD, (2) HIV and HCV treatment, (3) HIV pre-exposure prophylaxis, and (4) behavioral health services. Research is needed to understand differences in effectiveness between co-located and fully integrated care, combat the deleterious racial and ethnic legacies of the “War on Drugs,” and inform the delivery of psychiatric care. Increased access to harm reduction services is crucial

The cerebrovascular response to norepinephrine: A scoping systematic review of the animal and human literature.

Funder: CIHRFunder: NINDS NIH HHSIntravenous norepinephrine (NE) is utilized commonly in critical care for cardiovascular support. NE's impact on cerebrovasculature is unclear and may carry important implications during states of critical neurological illness. The aim of the study was to perform a scoping review of the literature on the cerebrovascular/cerebral blood flow (CBF) effects of NE. A search of MEDLINE, BIOSIS, EMBASE, Global Health, SCOPUS, and Cochrane Library from inception to December 2019 was performed. All manuscripts pertaining to the administration of NE, in which the impact on CBF/cerebral vasculature was recorded, were included. We identified 62 animal studies and 26 human studies. Overall, there was a trend to a direct vasoconstriction effect of NE on the cerebral vasculature, with conflicting studies having demonstrated both increases and decreases in regional CBF (rCBF) or global CBF. Healthy animals and those undergoing cardiopulmonary resuscitation demonstrated a dose-dependent increase in CBF with NE administration. However, animal models and human patients with acquired brain injury had varied responses in CBF to NE administration. The animal models indicate an increase in cerebral vasoconstriction with NE administration through the alpha receptors in vessels. Global and rCBF during the injection of NE displays a wide variation depending on treatment and model/patient