bluuebunny/crossref_metadata_2025 huggingface dataset:
Near-field thermionic-thermophotovoltaic energy converters
Authors: Liao Tianjun , Zhang Xin , Chen Xiaohang , Chen Jincan
Published: May 2019

We proposed a model of the coupling system composed of a vacuum thermionic power generator and a near-field thermophotovoltaic cell. The coupling system can simultaneously convert electrons and photons into electricity. Expressions for the efficiency and power output density of the coupling system are analytically derived. The influences of external and internal irreversible losses on the performance of the coupling system are discussed. The working temperature of the anode is calculated through an energy balance equation. The maximum efficiency and power output density of the coupling system are found to be obviously larger than those of a single vacuum thermionic power generator or a near-field thermophotovoltaic cell. Some parametric selective criteria are supplied and the boundaries of optimized parameters are determined. The results obtained here will be helpful to the optimal design and actual development of near-field thermionic-thermophotovoltaic cells.
Simulation of sub-nm carrier profiling by scanning frequency comb microscopy
Authors: Hagmann M. J. , Wiedemeier J.
Published: May 2019

A mode-locked laser focused on the tunneling junction of a scanning tunneling microscope (STM) superimposes a microwave frequency comb with hundreds of harmonics on the DC tunneling current. Each harmonic, at an integer multiple of the laser pulse repetition frequency, sets the present state-of-the-art for narrow linewidth at its frequency to enable low-noise measurements at an average laser power of several milliwatts. Measurements of the attenuation of the harmonics, which is caused by the spreading resistance, may be used to determine the resistivity of the sample. In Scanning Frequency Comb Microscopy (SFCM) feedback control of the tip-sample distance is based on the power at the harmonics. No DC bias voltage or DC tunneling current is required and the data rate is much higher than that with an STM. Simulations of the spatial distribution of the power dissipated in the sample show the feasibility of non-destructive true sub-nm resolution in the carrier profiling of semiconductors. With no DC bias voltage and no DC tunneling current band-bending and other changes to semiconductor samples in an STM are mitigated and there is a possibility for in vivo microscopy in biology and medicine.
Simultaneous magneto-electro-optical measurements in modulation-doped quantum well: An investigation on magneto-photoluminescence intensity oscillations
Authors: Haldar S. , Vashisht Geetanjali , Porwal S. , Sharma T. K. , Dixit V. K.
Published: May 2019

Quantum Hall and magneto-photoluminescence (magneto-PL) measurements are simultaneously performed on a GaAs quantum well to establish a detailed correlation between magneto-optical and magneto-transport properties of charge carriers. The longitudinal/transverse magneto-resistances under dark and illuminated conditions provide insight into an electron–electron interaction that pushes charge carriers toward the heterointerfaces. It is observed that photogenerated holes screen this interaction potential and annihilate the accumulation of electrons in the ground energy state. In this process, carriers from excited states are redistributed in lower energy sub-bands, which affect the quantum scattering time of carriers. In particular, the scattering time associated with an excited state is significantly reduced as compared to the ground state. Under this condition, the redistribution of charges among Landau states is probed by the magneto-PL measurements. Also, magneto-PL spectroscopy is used to estimate recombination time, carrier occupancy in Landau states, and Fermi energy as a function of a magnetic field. In our previous work [J. Lumin. 206, 342 (2019)], it was demonstrated that a variation in the strength/orientation of a magnetic field can control the recombination and separation of charges, where the PL spectra under a parallel magnetic field help to acquire anisotropic properties of charge carriers. Here, a similar method is used to estimate the anisotropic properties of carriers under an external electric field and then correlated with that obtained from quantum Hall measurements during illumination. Furthermore, a new method to record magneto-PL intensity oscillations is described, which can be used to realize magneto-optical properties of carriers without any line-shape fitting procedure.
Investigating the preservation of π–conjugation in covalently functionalized carbon nanotubes through first principles simulations
Authors: de Oliveira I. S. S. , Kagimura R. , Venezuela P. , Miwa R. H.
Published: May 2019

We performed a theoretical investigation of single-walled carbon nanotubes (CNTs) functionalized with triazine molecules. Upon adsorption, the influence of the molecule orientation on the CNTs’ electronic properties is examined by combining first-principles density functional theory calculations and simulations of X-ray Absorption Near-Edge Structure (XANES) at the C K-edge. Our calculations show that the electronic properties of functionalized CNTs can preserve the same features of pristine CNTs, for both semiconductor and metallic CNTs, depending on the orientation of the covalently bonded molecule. For that configuration, we observe a breakage of the CNT C–C bond at the molecule adsorption site. Moreover, the XANES spectra reveal that sp2 bonding hybridization is preserved along the CNT network. On the other hand, the electronic properties of pristine CNTs are no longer preserved for adsorbed molecule orientations resulting in intact C–C bond at the adsorption site. In this case, the XANES spectra indicate that the molecule-CNT interactions result in sp3 hybridization. Our findings help to elucidate whether π-conjugation is preserved in functionalized CNTs, demonstrating that calculations of XANES spectra are a powerful tool to resolve such systems.
Quantitative analysis of gas phase molecular constituents using frequency-modulated rotational spectroscopy
Authors: Lou Minghe , Swearer Dayne F. , Gottheim Samuel , Phillips Dane J. , Simmons Jay G. , Halas Naomi J. , Everitt Henry O.
Published: May 2019

Rotational spectroscopy has been used for decades for virtually unambiguous identification of gas phase molecular species, but it has rarely been used for the quantitative analysis of molecular concentrations. Challenges have included the nontrivial reconstruction of integrated line strengths from modulated spectra, the correlation of pressure-dependent line shape and strength with partial pressure, and the multiple standing wave interferences and modulation-induced line shape asymmetries that sensitively depend on source-chamber-detector alignment. Here, we introduce a quantitative analysis methodology that overcomes these challenges, reproducibly and accurately recovering gas molecule concentrations using a calibration procedure with a reference gas and a conversion based on calculated line strengths. The technique uses frequency-modulated rotational spectroscopy and recovers the integrated line strength from a Voigt line shape that spans the Doppler- and pressure-broadened regimes. Gas concentrations were accurately quantified to within the experimental error over more than three orders of magnitude, as confirmed by the cross calibration between CO and N2O and by the accurate recovery of the natural abundances of four N2O isotopologues. With this methodology, concentrations of hundreds of molecular species may be quantitatively measured down to the femtomolar regime using only a single calibration curve and the readily available libraries of calculated integrated line strengths, demonstrating the power of this technique for the quantitative gas-phase detection, identification, and quantification.
Rotation reversal of tokamak plasma subject to tearing-mode under resonant magnetic perturbation
Authors: Ivanov N. V. , Kakurin A. M.
Published: May 2019

The results of calculations and parametric analysis of the plasma rotation reversal subject to the tearing mode under magnetic perturbation of the same helicity are presented. The TEAR code used for the calculations is based on the visco-resistive MHD approximation that gives coupled diffusion-type equations for the magnetic flux perturbation and for the plasma rotation velocities in toroidal and poloidal directions. The resonant magnetic perturbation consists of both the traveling perturbation induced by eddy current in the vacuum vessel and an artificially applied nonrotating magnetic perturbation produced by a current layer outside plasma. The main attention is paid to conditions necessary for the plasma velocity reversals separately in toroidal and poloidal directions, as well as for the concurrent changes of both velocity directions. The dynamics of the plasma toroidal and poloidal rotation-profile variations are also presented.
Secondary electron effect on sustaining capacitively coupled discharges: A hybrid modeling investigation of the ionization rate
Authors: Wen Ying-Ying , Zhang Yu-Ru , Jiang Ge , Song Yuan-Hong , Wang You-Nian
Published: May 2019

A one-dimensional fluid/Monte Carlo hybrid model was used to quantitatively study the secondary electron effect on sustaining the discharge by examining the ionization induced by bulk electrons and secondary electrons under different external discharge parameters. The results indicate that as the voltage increases, secondary electrons gain more energy from the stronger electric field. Therefore, the ionization region induced by secondary electrons expands and the ionization rate becomes comparable to and even exceeds that of bulk electrons. As the pressure increases, secondary electrons collide with neutrals sufficiently, thus their contribution to the plasma generation becomes pronounced and eventually they dominate the discharge. Besides, the distribution of the secondary electron ionization rate varies from flat to saddle-shape, due to the energy loss at the discharge center at higher pressures. Finally, when the discharge gap expands, the electron density calculated in the case without secondary electrons increases linearly, whereas the value first increases and then decreases in the model with secondary electrons taken into account. The results obtained in this work are important for improving the high aspect ratio etching process by secondary electrons.
Observation of Kerr nonlinearity and Kerr-like nonlinearity induced by terahertz generation in LiNbO3
Authors: Wang Bo , Wang Chun , Wang Li , Wu Xiaojun
Published: May 2019

Femtosecond laser pulses interacting with LiNbO3 have been widely applied in intense terahertz generation, excitation and imaging of phonon polaritons, and modulating light. It is of great importance to study the nonlinearities induced by femtosecond laser pulses in LiNbO3. Here, we demonstrate that both Kerr nonlinearity and Kerr-like nonlinearity induced by terahertz waves occur under the interaction between laser pulses and LiNbO3 using optical pump-probe techniques. We show that the contribution of Kerr-like nonlinearity to pump-probe spectra varies with the interaction length because of the phase mismatching between the terahertz wave and the laser pulse. We also observed the excitation of the low frequency phonon polaritons. Experimental results are consistent with theoretical calculations.
Multiscale poromechanics of wet cement paste
Authors: Zhou Tingtao , Ioannidou Katerina , Ulm Franz-Josef , Bazant Martin Z. , Pellenq R. J.-M.
Published: May 2019

Significance

Capillary effects in cement paste are associated with multiple degradation mechanisms. Using a framework, we investigated the role of capillary forces in cement paste under partial saturation from the nanograins level to the mesoscale. We show that the largest capillary forces concentrate at the boundary between gel pores and larger capillary pores, inducing nonaffine deformations with correlations up to a few tens of nanometers. Our results suggest a homogenization length scale common to liquid and solid stresses correlated with the scale of inherent structural heterogeneities. This opens the route to studying the poromechanics of complex multiscale media with explicit fluid–solid coupling.
Cytosolic translational responses differ under conditions of severe short-term and long-term mitochondrial stress
Authors: Samluk Lukasz , Urbanska Malgorzata , Kisielewska Katarzyna , Mohanraj Karthik , Kim Min-Ji , Machnicka Katarzyna , Liszewska Ewa , Jaworski Jacek , Chacinska Agnieszka
Published: May 2019

Previous studies demonstrated that cells inhibit protein synthesis as a compensatory mechanism for mitochondrial dysfunction. Protein synthesis can be attenuated by 1) the inhibition of mTOR kinase, which results in a decrease in the phosphorylation of S6K1 and 4E-BP1 proteins, and 2) an increase in the phosphorylation of eIF2α protein. The present study investigated both of these pathways under conditions of short-term acute and long-term mitochondrial stress. Short-term responses were triggered in mammalian cells by treatment with menadione, antimycin A, or CCCP. Long-term mitochondrial stress was induced by prolonged treatment with menadione or rotenone and expression of genetic alterations, such as knocking down the MIA40 oxidoreductase or knocking out NDUFA11 protein. Short-term menadione, antimycin A, or CCCP cell treatment led to the inhibition of protein synthesis, accompanied by a decrease in mTOR kinase activity, an increase in the phosphorylation of eIF2α (Ser51), and an increase in the level of ATF4 transcription factor. Conversely, long-term stress led to a decrease in eIF2α (Ser51) phosphorylation and ATF4 expression and to an increase in S6K1 (Thr389) phosphorylation. Thus, under long-term mitochondrial stress, cells trigger long-lasting adaptive responses for protection against excessive inhibition of protein synthesis.
Communicative Styles, Rapport, and Student Engagement: An Online Peer Mentoring Scheme
Authors: Culpeper Jonathan , Kan Qian
Published: May 2019

This article investigates the communicative styles of three different peer mentors in the context of online language learning, and considers their effect on student engagement. A key objective is to show how an innovative corpus-based technique, keyword analysis, can be used as a first step towards identifying communicative styles. We view communicative style as a linguistic means by which rapport is managed amongst participants (Spencer-Oatey 2008). Our primary data include 685 forum posts, of which 273 (over 26,000 words) were by the mentors at the heart of our study. We show that the three mentors have different communicative styles: different rapport management orientations are achieved in different ways. Furthermore, we bring together multiple data sources, including participants’ posts and self-reported perception data. This allows us to find evidence on if and how communicative styles impact on student engagement and perception. We discovered that rapport enhancement aligns with increased active participation, especially if a self-effacement strategy is used, and positive student perception, but that the lack of such rapport does not automatically imply negative student perception.
Once-daily Doravirine in Human Immunodeficiency Virus Type 1–Infected, Antiretroviral-naive Adults: An Integrated Efficacy Analysis
Authors: Orkin Chloe , Molina Jean-Michel , Lombaard Johan , DeJesus Edwin , Rodgers Anthony , Kumar Sushma , Martin Elizabeth , Hanna George , Hwang Carey
Published: May 2019

Background

Doravirine (DOR) demonstrated noninferior efficacy to darunavir plus ritonavir (DRV+r) and efavirenz (EFV) in 2 ongoing phase 3 trials: DRIVE-FORWARD (NCT02275780) and DRIVE-AHEAD (NCT02403674).

Methods

This prespecified analysis pooled efficacy data through the first 48 weeks of DRIVE-FORWARD and DRIVE-AHEAD from the DOR groups (DOR/lamivudine [3TC]/tenofovir disoproxil fumarate [TDF] or DOR [100 mg daily] with emtricitabine [FTC]/TDF or abacavir [ABC]/3TC [n = 747]) compared with DRV+r (800/100 mg daily) with FTC/TDF or ABC/3TC (n = 383) or EFV/FTC/TDF (600/200/300 mg daily; n = 364). Efficacy assessments included the proportion of participants with human immunodeficiency virus type 1 (HIV-1) RNA <50 copies/mL and change in CD4+ T-cell count.

Results

At week 48, DOR demonstrated noninferior efficacy to DRV+r and EFV, with 84.1% of DOR-treated participants achieving HIV-1 RNA <50 copies/mL compared with 79.9% of the DRV+r and 80.8% of the EFV groups. Results were similar across demographic/prognostic subpopulations, including baseline plasma HIV-1 RNA, gender, race, and HIV-1 subtype. Mean increases from baseline in CD4+ T-cell count through 48 weeks were 195.5 cells/mm3 for DOR, 185.6 cells/mm3 for DRV+r, and 188.4 cells/mm3 for EFV/FTC/TDF.

Conclusions

DOR, as a single entity (in combination with other antiretroviral agents) and as a fixed-dose combination (DOR/3TC/TDF), demonstrated noninferior efficacy to DRV+r and EFV as assessed by the proportion of HIV-1-infected, treatment-naive adults with HIV-1 RNA <50 copies/mL.

Clinical Trials Registration

NCT02275780 and NCT02403674.
A guided nonparametric goodness-of-fit test with application to income distributions
Authors: Wen Kuangyu , Wu Ximing
Published: May 2019

We have developed a customizable goodness-of-fit test of a parametric density based on its distance to a consistently estimated density. This consistent estimate is obtained via a nonparametric density estimator with a parametric start, wherein the start is set to be the hypothesized parametric density. To cope with the influence of nonparametric estimation bias, nonparametric goodness-of-fit tests have resorted to remedies such as undersmoothing or convolution of the hypothesized density. Our test requires no such devices and possesses enhanced powers against alternative densities because the guided density estimator is free of the typical nonparametric bias under the null hypothesis and attains bias reduction when the underlying density is in a broad nonparametric neighborhood of the hypothesized density. Here, we establish the statistical properties of our test and use Monte Carlo simulations to demonstrate its finite sample performance. We use this test to examine the goodness-of-fit of normal mixtures to the distributions of log income of U.S. states. Although normality is rejected decisively, our results suggest that normal mixtures with two or three components suffice for all but one state.
Denmark: happy to fight, will travel
Authors: Jakobsen Peter Viggo , Rynning Sten
Published: May 2019

Over the past thirty years Denmark has become a capable and willing expeditionary ally, not least on account of an accelerated investment in new forces in the early to mid-2000s. With the 2005–2009 defence agreement the Danish Army scrapped its concept of conscripted mobilization and fully committed to deployable capacities; the navy became a ‘blue water’ navy given the commitment to build two combat support ships and three frigates and to scrap the submarine force; and the air force fully focused its organization on specialized and deployable ‘wings’. The literature suggests that external threats and technological innovation are key drivers of military change, which in broad strokes helps us understand Danish change—but not in full. As a small state, Denmark has been particularly attuned to the threat of abandonment by its NATO allies and the concomitant but rival desire to pay as little for defence as possible. NATO standing and money are thus the critical drivers of Danish military change and we are able to show how they have shaped three successive waves of military reform, beginning piecemeal in the 1990s and then continuing with deeper waves of reform in 2001 and 2014. Civil–military relations have throughout been quite solid and enabled change, which has to do with the political priority of securing Denmark's standing in NATO with as little money as possible, leaving it to the military services to figure out how to shape the toolkit.
Epilogue: In defense of disruptive democracy—A critique of anti-populism
Authors: Howse Robert
Published: May 2019

“Populism” is usually and pejoratively defined by the anti-populist elites to imply nativism, anti-liberalism, and anti-pluralism. This has little to do with many of today’s powerful critiques of and challenges to elite liberal democratic politics. Defenders of elite or “centrist” liberal democratic politics present a false choice between restoration or renewal of elite politics and a populist slide into authoritarianism and xenophobia. There is an important agenda of democratic reform disrupting elite liberal democratic politics, and anti-populism is not an authentic response to it. Radical democrats and democratic reformers, such as US congresswoman Alexandria Ocasio-Cortez, are not apostles of mob rule, contrary to the frequent caricature proposed by centrist liberal democrats in their “anti-populist” pose. They see an appropriate role for institutions such as independent courts as well as for experts in a stronger democracy.
Destruction of Cultural Heritage before the ICC
Authors: Dijkstal Haydee J
Published: May 2019

The case against Ahmad Al Faqi Al Mahdi marked the first prosecution and conviction for acts of destruction of cultural heritage before the International Criminal Court (ICC). Therefore, for the first time, the ICC recognized that although the crimes were committed against buildings and property, individuals and communities harmed by this destruction were victims who could participate in the proceedings and receive reparations. Using the Al Mahdi proceedings as a case study, this article examines how the prosecution of the destruction of cultural heritage, and also the reparations proceedings, were influenced by human rights considerations. This article concludes that human rights considerations influenced the Chamber’s reparations decision in the Al Mahdi case, particularly in regards to the victims’ recognition, participation and ability to claim a reparations award. However, the article argues that procedural and human rights considerations were not extended equally to the convicted individual and fell short of achieving an appropriate balance of rights.
The Flipside of Complementarity
Authors: Labuda Patryk I
Published: May 2019

A variety of human rights dilemmas were left unresolved in Rome. One issue likely to generate controversy is the relationship between the prohibition of double jeopardy, complementarity and minimal fair trial protections for defendants. Under the Rome Statute’s complementarity framework, the International Criminal Court (ICC) must defer to domestic proceedings if a state is handling the same case and the national authorities are not ‘unable or unwilling’ to prosecute the same person. Much ink has been spilt on Article 17 of the Statute and the ensuing case law, but less understood is the flipside of complementarity: under what circumstances is a state not allowed to prosecute defendants over whom the ICC has already exercised jurisdiction? With the case against Germain Katanga in the backdrop, this article argues that the ICC should take a more pro-active role in supervising secondary domestic proceedings against people previously convicted or acquitted in The Hague. Katanga’s return to the Democratic Republic of Congo to serve the remainder of his ICC-mandated sentence triggered a domestic trial implicating a variety of fair trial issues. Under a seldom-used provision in the Rome Statute, Article 108, the ICC Presidency was required to validate or reject Congo’s proceedings against Katanga. Not only did the Presidency allow his case to proceed, it prospectively abdicated any international oversight of national trials, while advancing sweeping normative claims about the irrelevance of human rights to the permissibility of secondary domestic trials. Three years later, Katanga languishes in a Congolese prison with little prospect of justice. Although the Katanga case is based on a unique set of facts, analogous developments in the cases against Saif Al-Islam Gaddafi and Jean-Pierre Bemba point to the growing likelihood of secondary domestic proceedings against people previously tried by the ICC, which in turn raises fundamental questions about the Rome Statute’s prohibition of double jeopardy and its relationship to complementarity and fair trial guarantees.
Comments on “How Errors Cumulate: Two Examples” by Roger Tourangeau
Authors: Olson Kristen
Published: May 2019

This paper provides a discussion of the Tourangeau (2019) Morris Hansen Lecture paper. I address issues related to compounding errors in web surveys and the relationship between nonresponse and measurement errors. I provide a potential model for understanding when error sources in nonprobability web surveys may compound or counteract one other. I also provide three conceptual models that help explicate the joint relationship between nonresponse and measurement errors.
High frequencies in TESS A–F main-sequence stars
Authors: Balona L A , Holdsworth D L , Cunha M S
Published: May 2019

The driving mechanism for high-frequency oscillations in some chemically peculiar Ap stars, the rapidly oscillating Ap stars (roAp stars), is not understood. The Transiting Exoplanet Survey Satellite mission (TESS) data provide an ideal opportunity to extend the number of roAp stars that might provide further clues to address this problem. From an examination of over 18 000 stars in TESS sectors 1–7, we have discovered high-frequency pulsations in 14 A–F stars, of which only 3 are classified as Ap stars. In addition to these new discoveries, we discuss the frequencies in nine previously known roAp stars. In one of these stars, HD 60435, we confirm a previous finding that the pulsations have lifetimes of only a few days. In another known roAp star, HD 6532, the relative amplitudes of the rotationally modulated sidelobes, which are generally used to estimate the inclination of the magnetic axis relative to the rotational axis, are significantly different from those found in ground-based B-band photometric observations. We also discuss four δ Scuti stars that appear to have independent frequencies similar to those of roAp stars.
The binary mass ratios of circumbinary planet hosts
Authors: Martin David V
Published: May 2019

Almost a dozen circumbinary planets have been found transiting eclipsing binaries. For the first time the observational bias of this sample is calculated with respect to the mass ratio of the host binaries. It is shown that the mass ratio affects transit detection in multiple, sometimes subtle ways, through stability and dynamics of orbits, dilution of transit depths, and the geometric transit and eclipse probabilities. Surprisingly though, it is found that these effects largely cancel out. Consequently, the transit detections in the Kepler mission are essentially unbiased with respect to mass ratio, and hence likely representative of the true underlying population. It is shown that the mass ratio distribution of circumbinary hosts may be the same as field binaries, and hence roughly uniform, but more observations are needed to deduce any subtle differences. These results are discussed in the context of close binary formation and evolution, of which the mass ratio is believed to be a marker, and other surveys for circumbinary planets including TESS and BEBOP.
The role of sham continuous positive airway pressure as a placebo in controlled trials: Best Apnea Interventions for Research Trial
Authors: Reid Michelle L , Gleason Kevin J , Bakker Jessie P , Wang Rui , Mittleman Murray A , Redline Susan
Published: May 2019

Study Objectives

The main objective of this study was to evaluate the role of sham continuous positive airway pressure (CPAP) compared to conservative medical therapy (CMT) as a control arm in the Best Apnea Interventions for Research (BestAIR) study by assessing differences in subjectively and objectively measured outcomes, adverse events, adherence, and retention rates.

Methods

BestAIR is a clinical trial aimed to identify important design features for future randomized controlled trials of CPAP. Participants with obstructive sleep apnea were randomized to one of four groups; two control arms (CMT, sham-CPAP) and two active CPAP arms (with and without behavioral interventions). Blood pressure and health-related quality of life outcomes were assessed at baseline, 6 and 12 months. Study outcomes, retention, and adverse event rates were compared between the two control arms. Sham-CPAP adherence and self-efficacy were also compared to active-CPAP adherence (without behavioral intervention).

Results

Our sample included 86 individuals in the control arms and 42 participants in the active-CPAP arm. There were no differences in longitudinal profiles in blood pressure, health-related quality of life outcomes, dropout rates, or adverse events in sham-CPAP group compared to CMT-only group (all ps > 0.05); standardized differences were generally small and with inconsistent directionality across measurements. When compared to active-CPAP, sham-CPAP was associated with 93 fewer minutes/night of usage over 12 months (p = 0.007) and lower outcome expectations (p < 0.05).

Conclusion

We observed no evidence of differences in objectively or subjectively measured outcomes with the use of sham-CPAP compared to CMT group. The lower adherence on sham-CPAP and poorer self-efficacy compared to active-CPAP may suggest differences in perceived benefit.

Registration

NCT 01261390 Best Apnea Interventions for Research (BestAIR) www.clinicaltrials.gov
Advancing science and practice using immersive virtual reality: what behavioral medicine has to offer
Authors: Persky Susan , Lewis Megan A
Published: May 2019

Interest in immersive virtual reality (VR) technologies is burgeoning as the hardware becomes less costly and more accessible to users, including researchers and practitioners. This commentary outlines the field of immersive VR and highlights applications of its use relevant to translational behavioral medicine. We describe the challenges facing VR applications for health and medicine, and how the core strengths of behavioral medicine can advance theory, research, and practice using VR. By highlighting potential uses of immersive VR alongside the challenges facing the field, we hope to inspire researchers to apply robust theories, methods, and frameworks to generate stronger evidence about the feasibility, acceptability, efficacy, and effectiveness of using this technology in translational behavioral medicine.
Operating Room-to-Incision Interval and Neonatal Outcome in Emergency Caesarean Section: A Retrospective 5-Year Cohort Study
Authors: Palmer E. , Ciechanowicz S. , Reeve A. , Harris S. , Wong D.J.N. , Sultan P.
Published: May 2019

(Anaesthesia. 2018;73:825–831)

In the United Kingdom, cesarean deliveries (CD) are classified based on a system that defines the urgency of the surgery. A category 1 CD is one in which there is an immediate threat to the life of the mother or fetus while a category 4 CD has no urgency and can be done at a time convenient to the patient and obstetric unit. There are limited data as to the effect of anesthesia technique used on the operating room-to-incision interval (ORII) and neonatal outcomes. The current study was undertaken to assess the relationship between CD category and ORII. ORII was the time from entering the operating room to the start of surgery and includes all of the time to induce anesthesia (with the exception of an epidural top-up started in the delivery room). Unlike decision-to-delivery interval, this gives a clearer impression of the influence of anesthesia on delivery times and outcomes. In addition, the investigators evaluated associations between anesthetic technique and ORII and neonatal outcomes for women undergoing a category 1 CD.
The Intrapartum and Perinatal Risks of Sleep-disordered Breathing in Pregnancy: A Systematic Review and Meta-Analysis
Authors: Brown N.T. , Turner J.M. , Kumar S.
Published: May 2019

(Am J Obstet Gynecol. 2018;219(2):147–161)

Sleep-disordered breathing (SDB) consists of a spectrum of respiratory and ventilation abnormalities ranging from snoring to obstructive sleep apnea and is an increasingly common condition in the nonobstetric population. It can be associated with morbidity. The incidence of SDB in pregnant women is unknown and many cases likely go undiagnosed. This systematic review and metaanalysis aimed to determine whether pregnant women diagnosed with SDB were more likely to have adverse intrapartum and perinatal outcomes compared with control subjects.
Postpartum Venous Thromboembolism Prophylaxis May Cause More Harm than Benefit: A Critical Analysis of International Guidelines Through an Evidence-based Lens
Authors: Kotaska A.
Published: May 2019

(BJOG. 2018;125:1109–1116)

Prothrombotic hemostatic changes make pregnant and postpartum women logical targets for venous thromboembolism (VTE) prophylaxis. Most obstetric VTE guidelines recommend low–molecular-weight heparin (LMWH) for many postpartum women, including most delivering by cesarean. Although evidence is limited, a small subset of pregnant and postpartum women is at very high risk of VTE. Women with a personal history of VTE, potent thrombophilia, or prolonged immobilization usually receive and likely benefit from antenatal and postpartum LMWH prophylaxis. This perception of benefit has spread to women with more common risk factors, in whom the risk of VTE is lower.
Obstetric Synthetic Oxytocin Use and Subsequent Hyperactivity/Inattention Problems in Danish Children
Authors: Stokholm L. , Juhl M. , Lønfeldt N.N. , Mikkelsen S.H. , Obel C. , Strandberg-Larsen K.
Published: May 2019

(Acta Obstet Gynecol Scand. 2018;97:880–889)

Synthetic oxytocin is commonly used to induce or augment labor. One report found that oxytocin augmentation of spontaneous labor occurred in almost 50% of deliveries in the United States. However, the widespread use of synthetic oxytocin for labor augmentation may be associated with adverse outcomes. For instance, uterine hyperstimulation and low Apgar scores have previously been reported. Oxytocin does cross the placenta and in a study of pregnant rats it was found to have a detrimental effect on central nervous system development of the offspring. Previous studies examining any potential effects of oxytocin use on attention deficit/hyperactivity disorder have had varying results. The objective of this population-based study was to examine the association between synthetic oxytocin use during labor and hyperactivity/inattention problems in the children.
Obstetric Emergencies as Antecedents to Neonatal Hypoxic Ischemic Encephalopathy, Does Parity Matter?
Authors: Liljestrom L. , Wikstrom A.K. , Jonsson M.
Published: May 2019

(Acta Obstet Gynecol Scand. 2018;97:1396–1404)

Hypoxic ischemic encephalopathy (HIE), associated with neonatal mortality and neurological morbidity, most commonly results from intrapartum asphyxia. One of the most prominent risk factors for HIE is the presence of an obstetric emergency during the intrapartum period, such as umbilical cord prolapse, uterine rupture, shoulder dystocia or placental abruption. Nulliparous patients tend to have a longer duration of labor, and may have different risk factors for HIE compared with multiparous patients. This study aimed to investigate the association between obstetric emergencies and the risk of moderate to severe HIE based on parity.
Prevalence and Prediction of Higher Estimated Gastric Content in Parturients at Full Cervical Dilatation: A Prospective Cohort Study
Authors: Desgranges F.P. , Simonin M. , Barnoud S. , Zieleskiewicz L. , Cercueil E. , Erbacher J. , Allaouchiche B. , Chassard D. , Bouvet L.
Published: May 2019

(Acta Anaesthesiol Scand. 2019;63:27–33)

There is an ongoing debate regarding the extent of gastric emptying in laboring parturients and the potential for pulmonary aspiration should conversion to general anesthesia be needed. While current guidelines state that laboring parturients should be allowed to drink clear fluids, there is insufficient evidence to support such recommendations in the context of parturients with higher than estimated gastric content. Using ultrasonography with parturients in the semirecumbent position (SR-CSA), which provides an antral cross-sectional area for measurement of gastric content, the authors of the present study determined the prevalence and predictive factors of higher estimated gastric content at full cervical dilatation in parturients allowed to drink during labor. Furthermore, the authors assessed whether SR-CSA alone can accurately identify a higher estimated gastric content.
Maternal Type 1 Diabetes and Risk of Autism in Offspring
Authors: Xiang A.H. , Wang X. , Martinez M.P. , Page K. , Buchanan T.A. , Feldman R.K.
Published: May 2019

(JAMA. 2018;320(1):89–91)

While maternal preexisting type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) diagnosed before 26 weeks gestation have previously been associated with increased risk of autism spectrum disorder (ASD) in the child, it is unclear whether maternal preexisting type 1 diabetes (T1D) is associated with an increased risk of ASD. This study examined the associations between risk of ASD in offspring and maternal T1D, T2D, and GDM.
Optimizing Oxygen Saturation Targets in Extremely Preterm Infants
Authors: Bizzarro M.J.
Published: May 2019

(JAMA. 2018;319(21):2173–2174)

While preterm newborns were once routinely exposed to unrestricted oxygen therapy, in the 1950s it was suggested that there may be an association between this practice and development of retinopathy of prematurity. Since then, 2 randomized clinical trials have supported this association [Supplemental Therapeutic Oxygen for Prethreshold Retinopathy of Prematurity (STOP-ROP) and Benefits of Oxygen Saturation Targeting (BOOST)] and also revealed that higher SpO2 ranges significantly increased the risk of severe pulmonary morbidity.
Placebo Versus Low-dose Ketamine Infusion in Addition to Remifentanil Target-controlled Infusion for Conscious Sedation During Oocyte Retrieval: A Double-blinded, Randomized Controlled Trial
Authors: Morue H.I. , Raj-Lawrence S. , Saxena S. , Delbaere A. , Engelman E. , Barvais L.A.
Published: May 2019

(Eur J Anaesthesiol. 2018;35:667–674)

Since the dawn of in vitro fertilization (IVF) 40 years ago, the technique for oocyte retrieval as well as the anesthesia provided for this procedure have evolved. Conscious sedation is now the most common anesthesia technique for oocyte retrieval in both the United Kingdom and the United States. At the current investigators’ institution, a combination of anxiolysis and titration of remifentanil using a target-controlled infusion (TCI) has been the standard anesthetic technique for oocyte retrieval since 2009. This study aimed to determine if the addition of a low-dose ketamine infusion to the standard TCI remifentanil would reduce the occurence of oxygen desaturation or respiratory depression during the procedure.
Hand Pattern Based on Second-to-Fourth Digit Ratio: Its Relationship to Sex, Body Mass Index, and Physical Activity
Authors: Al-Qattan Noha M. , Al-Kharashi Sara K. , Al-Hindi Ghada K. , Dammas Nada M. , Kattan Abdullah E. , Al-Qattan Mohammad M.
Published: May 2019

Background:

The second-to-fourth digit ratio is measured by dividing the length of the index finger by the length of the ring finger. A ratio <1 means that the ring finger is longer; this is known as the male pattern or “A” pattern. A ratio >1 means that the index finger is longer; this is known as the female pattern or “C” pattern. When both fingers are equal in length (ratio = 1), the pattern is labeled as “B” pattern; this may be seen in both sexes. None of the previously reported studies on this topic were reported in the plastic or hand surgery literature. Our aim is to increase the awareness of plastic and hand surgeons to these types of hand patterns and to correlate such patterns to sex, body mass index (BMI), and physical activity in a group of healthy medical students and interns.

Methods:

We conducted a cross-sectional study on 160 healthy medical students/interns. There were 82 females and 78 males between the ages of 20 and 30. A male pattern (pattern A) was defined as pattern A in both hands or pattern A in one hand and pattern B in the other hand. A female pattern (pattern C) was defined as pattern C in both hands or pattern C in one hand and pattern B in the other hand. The correlation between hand pattern and sex, BMI, and physical activity was done using the chi-square test and Fisher’s exact test. A P value of <0.05 was considered statistically significant.

Results:

Five participants (3.1%) had pattern B in both hands. Another 15 participants (9.4%) had a male pattern in one hand and a female pattern in the other hand. Both of these groups were excluded from the statistical analysis. Pattern A was significantly higher in males, and pattern C was significantly higher in females (P < 0.001). BMI and physical activity did not significantly affect the hand pattern in males. However, the correlations between hand pattern and both BMI and physical activity were significant in females (P = 0.005 for BMI) (P = 0.042 for physical activity).

Conclusions:

About 12.5% of the study group did not fit into a male or female pattern. In the remaining 87.5% of the participants, sex correlated with hand pattern. BMI and physical activity significantly affected the hand pattern in females. We believe that our study will encourage plastic surgeons to further investigate the correlation of different hands patterns to other variables of interest in plastic surgery such as masculine facial anthropometric values, hypoplastic breasts, gynecomastia, and lipodystrophy.
Treatment of Nasal Aging and Possible Long-term Nasal Enhancement with Fat Using Injectable Tissue Replacement
Authors: Cohen Steven R. , Womack Hayley A. , Hauch Adam T. , Delaunay Flore , Trivisonno Angelo
Published: May 2019

This article addresses nasal aging using a minimally invasive procedure with an algorithm that includes the diagnosis of a patient’s nose within the context of the individual’s facial anatomy. Pyriform augmentation for the elevation of tip projection and columellar strutting with injectable fat are, to our knowledge, applied for the first time as important steps in minimally invasive rhinoplasties. This procedure offers patients with more subtle nasal changes with aging or other causes to be treated with potentially long-lasting improvements, which can be easily retreated. New techniques using injectable liquid cartilage grafts are being explored.
Is it time for the 4th P in nurse practitioner education? Physical assessment, pharmacology, pathophysiology, and procedures: A systematic review
Authors: Schallmo Marianne K. , Godfrey Timian M. , Dunbar Darryn , Brown Kristen M. , Coyle Amanda , D'Aoust Rita F.
Published: May 2019

Background and purpose:

Nurse practitioners (NPs) perform diagnostic and clinical procedure skills in the acute, specialty, urgent, and primary care settings. Nurse practitioners surveyed on readiness for practice report a lack of confidence and education preparation for performing selected advanced diagnostic and skills. As NPs gain independent, full practice scope, it is imperative advanced diagnostic and procedure skills used in practice are taught in nurse practitioner curriculum. The purpose of this review is to document a systematic review of the literature, answering the following question: Among primary care NPs, does current program curriculum align with current procedures and skills in theclinical setting?

Methods:

PubMed, Cochrane, Scopus, CINAHL, and Embase were searched between inception and 2018 using the search terms “advanced practice nursing, clinical competence, diagnostic techniques or procedures, and primary health care.” Following the preferred reporting items for systematic reviews and meta-analysis guidelines, nine articles were included in the synthesis.

Conclusion:

There is scant research regarding NP educational preparation of skills and procedures. Study findings indicate that programs are not teaching all the procedures deemed important. Education should promote improved congruence between the skills and procedures taught in program curricula and those used in clinical practice.

Implications for practice:

It is critical to complete an education practice survey measuring skill and procedure preparation and competency at graduation. Survey results will determine whether skill and procedure guidelines are indicated for NP education. A recommendation may include minimal skills and procedure for all nurse practitioner curricula.
Factors Associated With Continuous Improvement by Local Boards of Health
Authors: Nguyen Tran Ha , Shah Gulzar H. , Schwartz Rachel D. , Jones Jeffery A.
Published: May 2019

Background:

The continuous improvement function, 1 of the 6 public health governance functions, can be usefully applied in the context of local boards of health (LBoHs) operations to target self-improvements.

Purpose:

The purpose of this study was to determine the engagement level of LBoHs in continuous improvement efforts and to identify factors associated with this function.

Methods:

Negative binomial regression was performed to analyze data from the 2015 Local Board of Health National Profile. The LBoH taxonomy was used as the guiding model. The taxonomy includes 6 governance functions as structural domains and LBoHs' characteristics and strengths as the central or seventh domain.

Results:

For the 17 items that comprise the continuous improvement domain, the mean of the dichotomous responses was 4.97 (SD = 3.41). The negative binomial regression analysis showed that the overall summary scale for the other 5 governance domains and the LBoHs' other strengths domain had a significant positive association with the governance domain continuous improvement domain (incidence rate ratio [IRR] = 1.05, P < .001). The 5 individual scales for the governance domains also had significant positive associations with the continuous improvement domain, which included the governance functions of policy development (IRR = 1.13, P < .001), resource stewardship (IRR = 1.18, P < .001), legal authorization (IRR = 1.09, P < .001, partnership engagement (IRR = 1.12, P < .001), and oversight (IRR = 1.29, P < .001). The scale for other characteristics and strengths also showed positive association with continuous improvement (IRR = 1.14, P < .001).

Conclusion:

The findings of this study revealed that there was room for improvement in LBoHs' engagement in the continuous improvement governance function. The results also identified other governance functions and LBoHs' characteristics as factors associated with their continuous improvement.