Intracardiac Echocardiography for Point-of-Care Guided Left Ventricular Assist Device Implantation: Surgical Implications for COVID-19.

Data from animal models is now available to initiate assessment of human safety and feasibility of wide-angle three-dimensional intracardiac echocardiography (3D ICE) to guide point-of-care implantation of percutaneous left ventricular assist devices in critical care settings. Assessment of these combined new technologies could be best achieved within a surgical institution with pre-existing expertise in separate utilization of ICE and Impella.

Work function of GaAs(hkl) and its modification using PEI: mechanisms and substrate dependence.

Spin-coating of poly(ethylenimine) (PEI) has been used to reduce the work function of GaAs (001), (110), (111)A and (111)B. The magnitude of the reduction immediately after coating varies significantly from 0.51 eV to 0.69 eV and depends on the surface crystal face, on the GaAs bulk doping and on the atomic termination of the GaAs. For all samples, the work function reduction shrinks in ambient air over the first 20 hours after spin coating, but reductions around 0.2-0.3 eV persist after 1 year of storage in air. Core-level photoemission of thin film PEI degradation in air is consistent with a two-stage reaction with CO2 and H2O previously proposed in carbon capture studies. The total surface dipole from PEI coating is consistent with a combination of internal neutral amine dipole and an interface dipole whose magnitude depends on the surface termination. The contact potential difference measured by Kelvin probe force microscopy on a cleaved GaAs heterostructure is smaller on p-doped regions. This can be explained by surface doping due to the PEI, which increases the band bending on p-doped GaAs where Fermi level pinning is weak. Both surface doping and surface dipole should be accounted for when considering the effect of PEI coated on a semiconductor surface.

Development of a doxycycline-inducible lentiviral plasmid with an instant regulatory feature.

Lentiviruses provide highly efficient gene delivery vehicles in both dividing and non-dividing cells. Inducible gene expression systems often employ a specific cell line that constitutively expresses a regulatory protein for transgene expression. As one of such inducible expression systems the Tet-On system uses a cell line expressing reverse tetracycline-responsive transcriptional activator (rtTA). The rtTA protein binds to the tetracycline-responsive element (TRE) in the promoter and activates transcription of a transgene in a doxycycline-dependent manner. To establish a universal and instant regulatory system without generating Tet-On cell lines, the cDNAs of rtTA and a testing target gene (PPM1B) were cloned in the bi-directional TRE-containing promoters. Here, we examined whether a basal leaky expression of rtTA allows instantly inducible expression of both rtTA itself and the target gene, PPM1B in a single plasmid using the two mini-CMV promoters. Transient transfection of the lentiviral plasmids into human embryonic kidney HEK293T cells showed a significant induction of PPM1B expression in response to doxycycline, suggesting that these lentiviral plasmids can be used as an instantly inducible mammalian expression vector. However, the expression of rtTA by lentiviral transduction shows a minimal expression without a consistent response to doxycycline, suggesting that the utility of these lentiviral vectors is limited. A potential solution to overcome lentiviral transgene inactivation is proposed.

Partial word knowledge in the absence of recall.

Attributes of words can be known even when the words are not currently retrievable. Although repeatedly demonstrated for semantic and contextual dimensions, the evidence is ambiguous for structural characteristics. The present research demonstrates significant above-chance first-letter knowledge across four ordinal levels of retrieval confidence for nonretrieved words--tip of the tongue (TOT), high familiar, low familiar, unfamiliar. Contrary to prior research, there was minimal evidence for syllable number knowledge, even at highest confidence levels. Initial letter recognition in the absence of retrieval resembles the recognition without identification in episodic memory (Cleary, Current Directions in Psychological Science 17: 353-357, 2008), and such implicit familiarity may contribute more generally to confidence assessments of word knowledge in both semantic and episodic memory domains. Furthermore, this outcome suggests that word feature priming in the form of partial phonological activation may occur to some extent for all words during a retrieval attempt, and even for ones that are judged to be unknown.

Conditioned place preferences for virtual alcohol cues.

This study examined whether a conditioned place preference (CPP) could be established for a virtual reality (VR) room that previously contained virtual alcohol stimuli. 298 undergraduates with varying levels of alcohol use completed six, three-minute conditioning sessions in which they were confined to one of two visually-distinct VR rooms: one of the VR rooms contained virtual alcohol cues (CS+) while the other VR room was neutral (CS-). Following conditioning, participants completed a three-minute test session during which they had unrestricted access to both VR rooms and neither room contained any alcohol-related cues. Although no virtual alcohol cues were present, participants with alcohol use (n = 248) spent significantly longer in CS+ relative to CS- compared to participants with alcohol non-use (n = 50) during the test session. This is the first study to show that a CPP can be established using virtual alcohol cues, in the absence of any actual alcohol administration. However, participants with alcohol use did not subjectively report enjoying CS+ more than CS- and explicitly chose CS- as their preferred room. Interestingly, these findings suggest that implicit and explicit measures of CPP may tap into distinct, separable processes and should be investigated further.

Large spectral extinction due to overlap of dipolar and quadrupolar plasmonic modes of metallic nanoparticles in arrays.

We explore the optical response of two-dimensional (2D) arrays of silver nanoparticles, focussing our attention on structures for which the individual particles in isolation support both dipolar and quadrupolar localised surface plasmon modes. For individual spheres we show that when dipolar and quadrupolar modes are excited simultaneously, interference leads to most of the scattered light being radiated in the forward direction. This is in contrast to what happens when each mode is excited on its own. We further show, using finite-element modelling that when such particles are assembled into square 2D arrays, the dipolar and quadrupolar modes can combine to produce a single peak in the optical density of the array. By simulating the field distributions associated with these modes we are able to illustrate the dual-mode character of this feature in the optical density. We have extended our examination of this effect by considering how the optical density of these arrays changes with incident angle for two polarisations (s and p).

Implantation of Impella CP left ventricular assist device under the guidance of three-dimensional intracardiac echocardiography.

Impella CP is a percutaneously inserted left ventricular assist device indicated for temporary mechanical cardiac support during high risk percutaneous coronary interventions and for cardiogenic shock. The potential application of Impella has become particularly relevant during the current COVID-19 pandemic, for patients with acute severe heart failure complicating viral illness. Standard implantation of the Impella CP is performed under fluoroscopic guidance. Positioning of the Impella CP can be confirmed with transthoracic or transoesophageal echocardiography. We describe an alternative approach to guide intracardiac implantation of the Impella CP using two-dimensional and three-dimensional intracardiac echocardiography. This new technique can be useful in selected groups of patients when fluoroscopy, transthoracic and transoesophageal echocardiography is deemed inapplicable or limited for epidemiological or clinical reasons. Intracardiac three-dimensional echocardiography is a feasible alternative to the traditional techniques for implantation of an Impella CP device but careful consideration must be given to the potential limitations and complications of this technique.

Comparison of dynamic changes in stressed intravascular volume, mean systemic filling pressure and cardiovascular compliance: Pilot investigation and study protocol.

The mean systemic filling pressure (MSFP) represents an interaction between intravascular volume and global cardiovascular compliance (GCC). Intravascular volume expansion using fluid resuscitation is the most frequent intervention in intensive care and emergency medicine for patients in shock and with haemodynamic compromise. The relationship between dynamic changes in MSFP, GCC and left ventricular compliance is unknown. We conducted prospective interventional pilot study following euthanasia in post cardiotomy adult sheep, investigating the relationships between changes in MSFP induced by rapid intravascular filling with fluids, global cardiovascular compliance and left ventricular compliance. This pilot investigation suggested a robust correlation between a gradual increase in the intravascular stressed volume from 0 to 40 ml/kg and the MSFP r = 0.708 95% CI 0.435 to 0.862, making feasible future prospective interventional studies. Based on the statistical modelling from the pilot results, we expect to identify a strong correlation of 0.71 ± 0.1 (95% CI) between the MSFP and the stressed intravascular volume in a future study.

In-Game Health Communication: Delivering Low-Fear Health Messages in a Low-Fear Videogame.

OBJECTIVE: Prior research has demonstrated that psychological immersion (or "transportation") into virtual gaming worlds can heighten influence from health-promotion messages embedded in the backgrounds of gaming scenes. However, research to date has only studied the effectiveness of embedding graphic, fear-based messages in the background of violent, first-person videogames. This study sought to examine whether transportation into a nonviolent videogame can heighten persuasion from low-fear, nongraphic health messages. METHODS: Willingness to drive under the influence of alcohol (DUI) was measured in an undergraduate sample (MAGE = 19) at the start of the semester, and n = 220 returned 0-3 months later to play a car-racing videogame. All were randomly assigned to play either a version of the game containing background billboards that delivered simple, text-based anti-DUI messages or consumer advertising. Self-reported levels of transportation were assessed, as well as postgame willingness to DUI. RESULTS: Exposure to anti-DUI messages from within the game predicted lower postgame willingness to DUI. Moreover, replicating prior research, the effect of message exposure was largest among those who reported higher levels of pregame willingness to DUI, and higher levels of in-game transportation. CONCLUSION: This study replicates prior research by suggesting that immersive videogames that promote transportation can be used to effectively deliver health communications. Results also expand prior research by providing the first evidence that such effects can generalize when health messaging orients around nongraphic, lower fear messages embedded within immersive but lower fear videogames.

To accurately estimate implicit influences on health behavior, accurately estimate explicit influences.

OBJECTIVE: This project considered how inattention to left-out variable error and measurement correspondence in the assessment of explicit measures can result in upwardly biased estimates of the predictive utility of implicit measures designed to predict health behaviors. METHOD: A pilot study (n = 96) used a cross-sectional design to predict beer consumption and a main study (n = 132) used a longitudinal design to predict binge drinking. In each study, a battery of 4 implicit inventories (implicit association test, personalized implicit association test, evaluative priming, and attribution misattribution paradigm) and a battery of correspondent explicit measures (based on the Reasoned Action Model and the Prototype Willingness Model) were administered to college youth. RESULTS: The Implicit Association Test and evaluative priming measures were not predictive of alcohol consumption in either study, but the personalized implicit association test (PIAT) and affective misattribution paradigm (AMP) accounted for between 5% and 12% in behavioral criteria, when analyzed in isolation or after explicit measures were statistically controlled following measurement conventions in this research domain. When implicit measures were folded into a structural equation model derived from the Reasoned Action and Prototype Willingness Models, The PIAT was no longer a significant predictor of behavior and the AMP resulted in a 1%-2% incremental increase in accounted for variance. CONCLUSION: Left-out variable error and measurement correspondence are core principles that need to be considered when modeling the relative contributions of implicit and explicit constructs in the prediction of health behaviors. (PsycINFO Database Record

Realisation of magnetically and atomically abrupt half-metal/semiconductor interface: Co2FeSi0.5Al0.5/Ge(111).

Halfmetal-semiconductor interfaces are crucial for hybrid spintronic devices. Atomically sharp interfaces with high spin polarisation are required for efficient spin injection. In this work we show that thin film of half-metallic full Heusler alloy Co2FeSi0.5Al0.5 with uniform thickness and B2 ordering can form structurally abrupt interface with Ge(111). Atomic resolution energy dispersive X-ray spectroscopy reveals that there is a small outdiffusion of Ge into specific atomic planes of the Co2FeSi0.5Al0.5 film, limited to a very narrow 1 nm interface region. First-principles calculations show that this selective outdiffusion along the Fe-Si/Al atomic planes does not change the magnetic moment of the film up to the very interface. Polarized neutron reflectivity, x-ray reflectivity and aberration-corrected electron microscopy confirm that this interface is both magnetically and structurally abrupt. Finally, using first-principles calculations we show that this experimentally realised interface structure, terminated by Co-Ge bonds, preserves the high spin polarization at the Co2FeSi0.5Al0.5/Ge interface, hence can be used as a model to study spin injection from half-metals into semiconductors.

Implications of the Implicit Association Test D-Transformation for Psychological Assessment.

Psychometricians strive to eliminate random error from their psychological inventories. When random error affecting tests is diminished, tests more accurately characterize people on the psychological dimension of interest. We document an unusual property of the scoring algorithm for a measure used to assess a wide range of psychological states. The "D-score" algorithm for coding the Implicit Association Test (IAT) requires the presence of random noise in order to obtain variability. Without consequential degrees of random noise, all individuals receive extreme scores. We present results from an algebraic proof, a computer simulation, and an online survey of implicit racial attitudes to show how trial error can bias IAT assessments. We argue as a result that the D-score algorithm should not be used for formal assessment purposes, and we offer an alternative to this approach based on multiple regression. Our critique focuses primarily on the IAT designed to measure unconscious racial attitudes, but it applies to any IAT developed to provide psychological assessments within clinical, organizational, and developmental branches of psychology-and in any other field where the IAT might be used.

The role of forgetting in undermining good intentions.

Evaluating others is a fundamental feature of human social interaction--we like those who help more than those who hinder. In the present research, we examined social evaluation of those who not only intentionally performed good and bad actions but also those to whom good things have happened (the lucky) and those to whom bad things have happened (the unlucky). In Experiment 1a, subjects demonstrated a sympathetic preference for the unlucky. However, under cognitive load (Experiment 1b), no such preference was expressed. Further, in Experiments 2a and 2b, when a time delay between impression formation (learning) and evaluation (memory test) was introduced, results showed that younger (Experiment 2a) and older adults (Experiment 2b) showed a significant preference for the lucky. Together these experiments show that a consciously motivated sympathetic preference for those who are unlucky dissolves when memory is disrupted. The observed dissociation provides evidence for the presence of conscious good intentions (favoring the unlucky) and the cognitive compromising of such intentions when memory fails.

Heteroepitaxial Growth of Ferromagnetic MnSb(0001) Films on Ge/Si(111) Virtual Substrates.

Molecular beam epitaxial growth of ferromagnetic MnSb(0001) has been achieved on high quality, fully relaxed Ge(111)/Si(111) virtual substrates grown by reduced pressure chemical vapor deposition. The epilayers were characterized using reflection high energy electron diffraction, synchrotron hard X-ray diffraction, X-ray photoemission spectroscopy, and magnetometry. The surface reconstructions, magnetic properties, crystalline quality, and strain relaxation behavior of the MnSb films are similar to those of MnSb grown on GaAs(111). In contrast to GaAs substrates, segregation of substrate atoms through the MnSb film does not occur, and alternative polymorphs of MnSb are absent.