bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of 3D printed bioinspired nacre-like structured materials with significantly enhanced thermal conductivity
Authors: Wang Haohuan , Huang Zhengyong , Li Jian , Wang Feipeng , Feng Zhanzu , Tian Hai , Zhao Haisen , Li Licheng
Published: April 2021

In this Letter, we report a simple approach for the preparation of bioinspired nacre-like structured materials with achievable high in-plane or through-plane thermal conductivity via digital light processing 3D printing under optimized printing parameters. Based on the 3D layer-by-layer formation, a vertical force exerted on each printing layer during the 3D printing process makes 2D platelets well-ordered in ultraviolet curable resin (hereafter UV resin), which is proved by the images of the scanning electron microscope and spectra of x-ray diffraction. It is found that a lower printing layer thickness leads to a higher orientation of Al2O3 platelets in the UV resin and greater thermal conductivity of the composites. The thermal conductivity of the structured composites reaches up to 2.622 W m−1 K−1 along the oriented direction at the loading of 30 wt. % of 2D Al2O3 platelets under the designed 3D printing layer thickness of 15 μm, which is about 14 times greater than that of pure UV resin. The surface temperature variations of the composites with time during heating and cooling, observed from the infrared thermograph, indicate the great potential of the 3D-printed structured materials for thermal management applications in electronic devices and electric equipment. It is predicted that fillers with greater intrinsic thermal conductivity and a larger diameter than the 3D printing layer thickness will lead to composites with greater thermal dissipation capability.
Time-lens photon Doppler velocimetry (TL-PDV)
Authors: Chu Pinghan , Kilic Velat , Foster Mark A. , Wang Zhehui
Published: April 2021

We describe a time lens (TL) to expand the dynamic range of photon Doppler velocimetry (PDV) systems. The principle and preliminary design of a TL-PDV system are explained and shown to be feasible through simulations. In a PDV system, an interferometer is used for measuring frequency shifts due to the Doppler effect from the target motion. However, the sampling rate of the electronics could limit the velocity range of a PDV system. A four-wave-mixing (FWM) TL applies a quadratic temporal phase to an optical signal within a nonlinear FWM medium (such as an integrated photonic waveguide or a highly nonlinear optical fiber). By spectrally isolating the mixing product, termed the idler, and with appropriate lengths of dispersion prior to and after this FWM TL, a temporally magnified version of the input signal is generated. Therefore, the frequency shifts of PDV can be “slowed down” with the magnification factor M of the TL. M = 1 corresponds to a regular PDV system without a TL. M = 10 has been shown to be feasible for a TL-PDV system. The use of this effect for PDV can expand the velocity measurement range and allow for the use of lower bandwidth electronics. TL-PDV will open up new avenues for various dynamic material experiments.
Accuracy trade-off between one-electron and excitonic spectra of cuprous halides in first-principles calculations
Authors: Wu Yujing , Jiang Zeyu , Tan Hengxin , Li Yuanchang , Duan Wenhui
Published: April 2021

Because of the sophisticated error cancellation in the density functional theory (DFT)-based calculations, a theoretically more accurate input would not guarantee a better output. In this work, our first-principles GW plus Bethe–Salpeter equation calculations using pseudopotentials show that cuprous halides (CuCl and CuBr) are such extreme cases for which a better one-electron band is not accompanied with a better exciton binding energy. Moreover, we find that the exchange interaction of Cu core electrons plays a crucial role in their ground-state electronic properties, especially in the energy gap and macroscopic dielectric constant. Our work provides new insights into the understanding of the electronic structure of cuprous halides from the DFT perspective.
Fano-like resonances in nanostructured thin films for spatial filtering
Authors: Grineviciute Lina , Nikitina Julianija , Babayigit Ceren , Staliunas Kestutis
Published: April 2021

Fano-like resonant coupling of electromagnetic radiation with planar waveguiding modes of nanostructured thin films is proposed and realized experimentally. Different from conventional Fano coupling to compact resonators with the discrete spectrum, we report Fano-like coupling to infinitely extended planar waveguiding modes of the spatially unbound system. We fabricated the films by the ion beam sputtering method on nano-modulated substrates. The observed Fano-like process shows extremely strong sensitivity with respect to the wavelength and especially to the incidence angle of the radiation and can potentially be used for frequency and spatial filtering of light in transmission/reflection through/from such nanostructured thin films.
A robust fiber-based quantum thermometer coupled with nitrogen-vacancy centers
Authors: Zhang Shao-Chun , Dong Yang , Du Bo , Lin Hao-Bin , Li Shen , Zhu Wei , Wang Guan-Zhong , Chen Xiang-Dong , Guo Guang-Can , Sun Fang-Wen
Published: April 2021

The nitrogen-vacancy center in diamond has been broadly applied in quantum sensing since it is sensitive to different physical quantities. Meanwhile, it is difficult to isolate disturbances from unwanted physical quantities in practical applications. Here, we present a fiber-based quantum thermometer by tracking the sharp-dip in the zero-field optically detected magnetic resonance spectrum in a high-density nitrogen-vacancy ensemble. Such a scheme can not only significantly isolate the magnetic field and microwave power drift but also improve the temperature sensitivity. Thanks to its simplicity and compatibility in implementation and robustness, this quantum thermometer is then applied to the surface temperature imaging of an electronic chip with a sensitivity of 18mK/Hz. It thus paves the way to high sensitive temperature measurements in ambiguous environments.
The scales of the leading-edge separation bubble
Authors: Smith J. A. , Pisetta G. , Viola I. M.
Published: April 2021

The leading-edge separation bubble is a flow feature occurring on the suction side of thin foils as a result of separation at the sharp leading-edge followed by reattachment downstream along the chord. For a flat plate at zero angle of attack, the reattachment length of the bubble depends on the plate thickness t. At a nonzero incidence, instead, the underlying scale governing bubble length is not clear. To investigate, we undertake a critical review of experimental and theoretical studies and develop an analytical formulation to predict the reattachment length of plates both at zero and at small incidences. We focus on conditions where the bubble is turbulent, i.e., when transition occurs at a negligible distance from the point of separation. This occurs at thickness- and chord-based Reynolds numbers Ret≳104, Rec≳105. At angle of attack α = 0, we find that the reattachment length is xR≈4.8t when the chord-to-thickness ratio is c/t>12. At α>0, we find that xR/c=πσα2, where σ≈7.9 is the inverse of the growth rate of a turbulent free shear layer. These results allow estimating xR on the thin wings of, for example, aerial vehicles and yacht sails.
Designing a consistent implementation of the discrete unified gas-kinetic scheme for the simulation of three-dimensional compressible natural convection
Authors: Wen Xin , Wang Lian-Ping , Guo Zhaoli
Published: April 2021

Discrete unified gas-kinetic scheme (DUGKS) has been developed as a robust and accurate approach for thermal compressible flow simulations; however, designing an efficient and accurate lattice velocity model to take full advantage of DUGKS remains a challenge. In this study, we apply DUGKS to simulate three-dimensional compressible natural convection in an enclosure with a large temperature difference, without making the Boussinesq approximation. The Chapman–Enskog analysis indicates that the fourth-order moments of equilibrium is needed for the heat flux evaluation in the energy equation, implying that the fourth-order Hermite expansion of equilibrium and thus at least an eighth-order Gauss–Hermite quadrature are needed for accurate simulation of the Navier–Stokes–Fourier system. For this purpose, a highly efficient lattice velocity model, D3Q77A9, is derived, which provides a Gauss–Hermite quadrature of ninth-order accuracy in three dimensions. The accuracy of this D3Q77A9 model is demonstrated by simulating compressible natural convection flows in both two-dimensional and three-dimensional cavities. An error analysis is performed to emphasize the importance of combining a quadrature with an adequate degree of precision and a proper order of Hermite expansion of the equilibrium distribution.
Electronic structure, dynamic stability, elastic, and optical properties of MgTMN2 (TM = Ti, Zr, Hf) ternary nitrides from first-principles calculations
Authors: Xue Feng-ning , Sun Mao-song , Feng Xiao-yue , Lu Yong , Zhang Ji-cai
Published: April 2021

Ternary nitride semiconductors with tunable electronic structure and charge transport properties have attracted increasing attention as optoelectronic materials. The recently discovered ternary MgTMN2 (TM=Ti,Zr,Hf) are predicted to be nondegenerate semiconductors with visible-range optical absorption onsets. In the present study, the electronic structure, elastic properties, optical absorption spectrum, and dynamic stability of the MgTMN2 system have been systematically studied by first-principles calculations based on the density functional theory. These compounds show semiconductor characteristics with a bandgap ranging from 1.0 to 1.5 eV predicted by the Heyd–Scuseria–Ernzerhof approach. Compared to the traditional semiconductors of Si and GaAs and III–V nitrides of GaN and AlN, these ternary nitrides have stronger resistance to external compression, shear strain, and deformation due to the larger elastic modulus. MgTiN2 shows a strong anisotropy characteristic along the xy plane and z axis, while for MgZrN2 and MgHfN2, a weak elastic anisotropy is predicted. The absorption regions of these compounds are mainly concentrated in the ultraviolet region, and MgTiN2 is more sensitive to visible light with respect to the other two compounds. The thermodynamic stability of MgTiN2, MgZrN2, and MgHfN2 is verified by the stable phonon dispersion relations. It is found that the most stable low Miller index surface is (110) for MgTiN2 and (100) for MgZrN2 and MgHfN2.
Hydrodynamic instability of free river bars
Authors: Mahato Rajesh Kumar , Ali Sk Zeeshan , Dey Subhasish
Published: April 2021

In this paper, we explore the hydrodynamic instability of free river bars driven by a weakly varying turbulent flow in a straight alluvial channel with erodible bed and non-erodible banks. We employ linear stability analysis in the framework of depth-averaged formulations for the hydrodynamics and the sediment transport. A significant fraction of the sediment flux is considered to be in suspension. The analysis is performed for the alternate pattern of river bars at the leading order followed by the next order, covering the effects of flow regime. We find that the unstable region bounded by a marginal stability curve depends significantly on the shear Reynolds number, which demarcates different flow regimes, and the Shields number and the relative roughness (particle size to flow depth ratio). The results at the next order stabilize the bars with longer wavenumbers. The variations of threshold aspect ratio with Shields number and relative roughness are studied for different flow regimes. In addition, for a given Shields number and relative roughness, the diagram of threshold aspect ratio vs shear Reynolds number is explained. Unlike the conventional theories of bar instability, the analysis reveals limiting values of Shields number and relative roughness beyond which the theoretical results at the next order produce infeasible regions of instability. The limiting values of Shields number and relative roughness appear to reduce, as the shear Reynolds number increases.
Prediction of massless Dirac fermions in a carbon nitride covalent network
Authors: Cao Jiangming , Huang Zhi-Quan , Macam Gennevieve , Gao Yifan , Nulakani Naga Venkateswara Rao , Ge Xun , Ye Xiang , Chuang Feng-Chuan , Huang Li
Published: April 2021

Two-dimensional (2D) Dirac materials have received tremendous attention due to their potential applications in spintronics and energy applications. Motivated by recent experimental synthesis of a carbon nitride network with a C22N4 stoichiometry, the N-doped graphdiyne, or pyrazinoquinoxaline-based graphdiyne (PQ-GDY), we studied the electronic and topological properties of the PQ-GDY monolayer using first-principles calculations. Surprisingly, we found that the PQ-GDY monolayer indeed is a 2D Dirac semimetal also known as 2D topologically nontrivial semimetal. The linear band dispersions around the Dirac point are mainly composed of the bonding and antibonding pz-orbitals of C and N atoms. In combination with parity analysis, we found that the mechanism of band inversion in PQ-GDY is similar to the strain-induced Dirac cone in GDY. The underlying physical property of strained GDY is equivalent to expanding the single center benzene into the three benzene rings observed in PQ-GDY. Finally, the formed Dirac cone located on the Y−Γ high-symmetry line is very robust, and a bandgap is opened only after including a large artificial spin–orbit coupling, which transforms it to a 2D topological insulator.
Effects of slope and speed of escalator on the dispersion of cough-generated droplets from a passenger
Authors: Li Zhaobin , Zhang Xinlei , Wu Ting , Zhu Lixing , Qin Jianhua , Yang Xiaolei
Published: April 2021

During the pandemic of COVID-19, the public is encouraged to take stairs or escalators instead of elevators. However, the dispersion of respiratory droplets in these places, featured by slopes and human motion, is not well understood yet. It is consequently unclear whether the commonly recommended social-distancing guidelines are still appropriate in these scenarios. In this work, we analyze the dispersion of cough-generated droplets from a passenger riding an escalator with numerical simulations, focusing on the effects of the slope and speed of the escalator on the droplet dispersion. In the simulations, a one-way coupled Eulerian–Lagrangian approach is adopted, with the air-flow solved using the Reynolds-averaged Navier–Stokes method and the droplets modeled as passive Lagrangian particles. It is found that the slope alters the vertical concentration of the droplets in the passenger's wake significantly. The deflection of cough-generated jet and the wake flow behind the passenger drive the cough-generated droplets upwards when descending an escalator and downwards when ascending, resulting in both higher suspension height and larger spreading range of the viral droplets on a descending escalator than on an ascending one. These findings suggest that the present social-distancing guidelines may be inadequate on descending escalators and need further investigation.
Hydrogen diffusion in proton-exchanged lithium niobate single crystals
Authors: Dörrer Lars , Tuchel Philipp , Hüger Erwin , Heller René , Schmidt Harald
Published: April 2021

Hydrogen diffusion in proton-exchanged congruent LiNbO3 single crystals is investigated in the temperature range between 140 and 200 °C. The proton-exchange process carried out in a mixture of benzoic acid and lithium benzoate (1 mol. %) results in an up to 2 μm thick surface layer where Li is substituted by H for about 60% (about 12 at. % H within LiNbO3) as determined by nuclear reaction analysis. For the diffusion experiments, deuterated benzoic acid is used as a tracer source and the hydrogen/deuterium isotope-exchange occurs at temperatures of 200 °C and below. Isotope sensitive depth profile analysis is done by secondary ion mass spectrometry. From the experimental results, effective diffusivities governing the lithium/hydrogen exchange and tracer diffusivities of deuterium within the exchanged layer are extracted. Both types of diffusivities can be described by the Arrhenius law with an activation enthalpy of about 1.2 eV, while the effective diffusivities are lower by three orders of magnitude. This result shows that the diffusion of hydrogen is not the rate-determining step for the proton-exchange process. Possible diffusion mechanisms of hydrogen tracer diffusion are discussed.
Tensors and NMR with Magic Angle Spinning
Authors: Chen Bo
Published: April 2021

Our introduction of density matrix and operator formalism will suffice the analyses of NMR pulse sequences. In this chapter, we will introduce a new concept called tensor. Its implementation will greatly simplify the analyses of spin dynamics in many more complicated scenarios than that of individual spin angular momentum operators. We will first briefly introduce the Wigner-Eckart theory, which provides a framework to describe the general principles regarding tensors rotation. The Wigner-Eckart theory has many more advanced applications that can make your heads (and mine) spin. But please don't be intimidated. We will limit our discussion to its applications relevant to NMR. Specifically, we will demonstrate the derivation of the effect of Magic Angle Spinning (MAS) on interactions essential to NMR. The tensor representation will lead to a general format for the analysis of MAS NMR experiments by AHT. This chapter will be the foundation for our discussion of the recoupling in Chapter 6 and decoupling in Chapter 7.
Fundamentals of Recoupling Techniques Under Magic Angle Spinning
Authors: Chen Bo
Published: April 2021

Our discussion in Chapter 5 demonstrated the application of MAS enhances spectral resolution and sensitivity by concentrating the broad static powder pattern into sharp individual spinning side bands and the central line. In this process, the anisotropic interactions are suppressed.

Meanwhile, anisotropy also encodes molecular structure and dynamics. For example, chemical shielding or dipolar tensor, their magnitudes and orientations inform us the dynamics and structural information of molecules. Therefore, NMR spectra can be modulated by selected anisotropy to retrieve dynamics and structural parameters. For example, distances between selectively isotope labeled sites can be measured accurately by recoupling of dipolar interactions, or the dynamics of amide nitrogen can be interrogated.

Hence, it seems impossible to simultaneously achieve spectral resolution enhancement and retrieve maximized structural information, as they demand conflicting requirements in the same experiment: these anisotropic interactions need to be suppressed for resolution purpose, yet they need to be kept alive for probing the valuable structural and dynamic parameters. The solution is to achieve artificial control of anisotropic interactions in multidimensional NMR. By exploiting the interference effects between RF pulsing and MAS, anisotropic interactions can be selectively resurrected to modulate the spectral features along the indirect dimension, while they are dormant during direct detection dimension by MAS and decoupling. A variety of RF pulse sequences were designed for this purpose.

In addition to artificially designed sequences, the recoupling effects exist intrinsically due to the interference effects associated with incommutable homogeneous interactions, which incurs undesirable line broadening despite MAS.

We will start our discussion by reviewing the simple but classical recoupling of homo and heteronuclear dipolar interactions by rotary resonances1, 2. These derivations will naturally help us understand the widely the recoupling of homonuclear dipolar interactions by Dipolar-Assisted Rotational Resonance (DARR)3. Then we will review recoupling of dipolar interactions by C4, 5 and R6, 7 symmetry sequences that exploit more general symmetry principles of sequential pulse trains. Detailed analyses will be presented for C78 and SPC59 sequence.

In addition to continuous irradiation, a variety of RF sequences were designed with intermittent pulses to recouple interactions. In the case of homonuclear recoupling sequences, finite pulse radio frequency driven recoupling (fpRFDR)10, RFDR, and PITHIRDS will be analyzed. Analysis of REDOR11 will be presented at the end to demonstrate the recoupling of heteronuclear dipolar interactions. It shares similar features to RFDR in the sequence layout, but was much earlier.

Let's start from some classical examples in the history of ssNMR, and you will see this is a very exciting journal that you don't want to miss.
Fundamentals of Decoupling Techniques Under Magic Angle Spinning
Authors: Chen Bo
Published: April 2021

Decoupling of interactions is a common and essential practice in protein NMR experiments. High-resolution 13C/15N spectra require efficient proton decoupling. Proton homonuclear decoupling is also necessary to characterize intrinsic relaxation or for proton detection at high MAS. However, it is more complicated to understand than the recoupling of interactions, due to the strong and homogeneous proton dipolar network.

Due to the nature of many-body problem, spin physics of decoupling is still a topic not fully understood. Our goal is to introduce the fundamentals of popular theoretical frameworks. We will start our discussion with a qualitative description to differentiate the effect of inhomogeneous and homogeneous interactions on the spectral resolution and relaxation. Then, the mechanism of Lee-Goldburg (LG) sequence to decouple homonuclear dipolar interaction will be discussed, based on AHT. Quantitative analysis of NMR linewidth will be presented to understand the effect of decoupling by MAS alone. Subsequently, decoupling by strong RF irradiation at low MAS will be analyzed in the absence of strong proton homonuclear dipolar coupling network. In the presence of strong proton coupling network, with simultaneous MAS and RF irradiation, interferences arise, and situations immediately become very challenging for AHT. Analytical solutions can be obtained at commensurate MAS and RF irradiation frequencies. To analyze decoupling phenomena beyond this regime, we introduce the Floquet theory, focusing on the principles of Floquet theory.
Boosting can explain patterns of fluctuations of ratios of inapparent to symptomatic dengue virus infections
Authors: Alexander Laura W. , Ben-Shachar Rotem , Katzelnick Leah C. , Kuan Guillermina , Balmaseda Angel , Harris Eva , Boots Mike
Published: April 2021

Significance

In many important human diseases, a large proportion of infections do not lead to symptoms, but we typically have little understanding of the cause, impact, and dynamics of such inapparent infections. Our data from the Nicaragua Pediatric Cohort show that the dynamics of both symptomatic and inapparent infections are complex, such that in some years there are many symptomatic cases, but in others the cases are predominantly inapparent. Using epidemiologic models, we show that boosting the immune system is a parsimonious mechanism that can explain these patterns. This is important because it suggests that boosting is an important to the epidemiology of dengue and moreover that immune mechanisms can lead to complex inapparent infection dynamics.
Signatures of immune dysfunction in HIV and HCV infection share features with chronic inflammation in aging and persist after viral reduction or elimination
Authors: Lopez Angel Cesar J. , Pham Edward A. , Du Huixun , Vallania Francesco , Fram Benjamin J. , Perez Kevin , Nguyen Thai , Rosenberg-Hasson Yael , Ahmed Aijaz , Dekker Cornelia L. , Grant Philip M. , Khatri Purvesh , Maecker Holden T. , Glenn Jeffrey S. , Davis Mark M. , Furman David
Published: April 2021

Significance

Chronic inflammation contributes to morbidity and mortality in aging, but whether similar mechanisms underlie dysfunction in infection-associated chronic inflammation is unclear. Using a multicohort systems immunology approach, we identified signatures of immune dysfunction that are shared in aging and chronic viral infections, namely HIV and hepatitis C virus. We show that these shared dysfunctions persist despite viral clearance, and we describe the changes in functional coordination that occur during viral eradication. Finally, we highlight a partial restoration in interferon-α sensitivity across all major immune cell lineages as viral load drops. Our findings suggest a broad and persistent functional remodeling and deterioration of the human immune system despite removal of a chronic pathogenic burden that shares features of chronic inflammation in aging.
Dynamic prioritization of COVID-19 vaccines when social distancing is limited for essential workers
Authors: Buckner Jack H. , Chowell Gerardo , Springborn Michael R.
Published: April 2021

Significance

Vaccines are a key intervention to reduce the burden of the COVID-19 pandemic. However, vaccine supply and administration capacity will initially be limited. Due to these constraints, it is critical to understand how vaccine deployment can be targeted to minimize the overall burden of disease. In this paper, we solve for optimal dynamic strategies to allocate a limited supply of vaccines over a population differentiated by age and essential worker status that minimizes the number of total deaths, years of life lost, or infections. We find that older essential workers are typically targeted first. However, depending on the objective and alternative model scenarios considered, younger essential workers may be prioritized to control spread or seniors to directly control mortality.
Impact of Cuddler Service-Learning Program in Medical Student Education of Opioid use Disorder in Pregnancy and Neonatal Opioid Withdrawal Syndrome
Authors: Gummadi Nina H. , D'Amico Maria , Chandra Phanirekha , Krumholz Julia O. , Mumber Hannah E. , Hoyo Leonie , Miller Melissa , Borba Christina P. , Wachman Elisha M.
Published: April 2021

Background

Given the increasing incidence of neonatal opioid withdrawal syndrome (NOWS), medical student training on substance use disorders (SUDs) and opioid use disorder (OUD) in pregnancy must be augmented. Through the Cuddling Assists in Lowering Maternal and Infant Stress (CALM) service-learning program, medical students attend SUD-related didactics and provide monthly cuddling services to infants with NOWS. Objective: This study examines the impact of CALM on medical students’ attitudes toward individuals with SUDs and self-reported comfort with clinical skills related to caring for this population.

Methods

Self-reported pre- and post-survey data was collected at the beginning and end of an academic year from the intervention group, CALM cuddlers, and the control group, non-cuddlers for 2 years. Mean total survey scores and individual survey questions using a 3-point Likert scale were compared before and after 1 year of participation for cuddlers and for non-cuddlers using paired t-tests and two sample t-tests.

Results

The mean total score increased for cuddlers after participation in the intervention (MD 0.13, SD 0.26, p = 0.03). Mean scores for the comfort-related subset of questions also increased significantly for cuddlers after participation in the intervention (MD 0.22, SD 0.41, p = 0.01). Cuddlers felt more comfortable discussing substance use with appropriate language (72.0% vs 51.5%, p = 0.03), talking with patients about substance use (72.0% vs 36.0%, p = 0.01), and asking about substance use or recovery (80.0% vs 48.0%, p = 0.01).

Conclusion

OUD- and NOWS-related service-learning positively impacts student attitudes and self-reported comfort with skills related to caring for individuals with SUDs, such as communicating about substance use.
Trends in Personal and Family Member Opioid Prescriptions Prior to a Diagnosis of an Opioid-Related Problem among Adolescents and Young Adults
Authors: Cohrs Austin C. , Pacula Rosalie Liccardo , Dick Andrew W. , Stein Bradley D. , Druss Benjamin G. , Leslie Douglas L.
Published: April 2021

Background

Efforts to reduce the risk of opioid misuse are often focused on reducing unnecessary prescriptions for opioid medications or reducing the dose prescribed; however, not all misuse occurs in individuals with a personal prescription. This study examined trends in the proportion of adolescents and young adults (AYAs) who had an opioid-related problem (ORP) and who also had a personal opioid prescription drug claim or had a family member with an opioid prescription drug claim prior to the ORP diagnosis.

Methods

A retrospective cohort design was used to analyze longitudinal claims data. We identified individuals aged 12 to 25 years who had a newly diagnosed ORP in the years 2006 to 2014. Trends over time in personal or family opioid prescription drug claims within 1 year prior to ORP diagnosis were examined.

Results

We identified 53,560 AYAs with an ORP diagnosis. Over the entire study period, 40% of AYAs with an ORP diagnosis had a personal opioid prescription in the year prior to diagnosis, and 48% had a family member with an opioid prescription in the prior year. While the proportion of AYAs with a family prescription remained constant, the proportion with a personal prescription fell from 77.1% in 2006 to 27.3% in 2014.

Conclusions

The number of AYAs with an ORP increased over time, yet the proportion with a personal opioid prescription claim prior to their diagnosis decreased over time. This suggests that providers are paying greater attention to prescribing opioids to AYAs directly, although prescriptions to family members may still remain a point of access.
Trait Mindfulness and Cannabis Use–Related Factors in Adolescents and Young Adults with Frequent Use
Authors: Lin Jessica A. , Harris Sion Kim , Shrier Lydia A.
Published: April 2021

Background

Mindfulness-based interventions (MBIs) are effective in adult substance-use treatment and may be helpful for adolescents and young adults (AYAs). One target of MBIs is to improve trait mindfulness, which has been associated with better lifestyle and health outcomes. To inform MBIs for reducing cannabis use in AYAs, we sought to identify how trait mindfulness was associated with cannabis-related problems and quit attempts, as well as with motivation to change use in youth who report frequent use.

Methods

Participants aged 15–24 years using cannabis ≥ 3x/week were recruited from AYA clinics in a northeastern US city to participate in a cannabis-use intervention pilot, randomized trial. At baseline, we assessed cannabis-use history, problems associated with use, attempts to quit, and trait mindfulness. All participants were offered two sessions of motivational enhancement therapy, during which they rated motivation to quit cannabis. Regression analyses were conducted to assess associations between trait mindfulness and cannabis use–related problems, attempts to quit, and motivation to change.

Results

Seventy participants, mean age 20.7 ± 1.9 years, enrolled. Sixty percent identified as female, 47% as Black non-Hispanic, and 31% as Hispanic. Participants started using cannabis at mean age 15.0 ± 2.8 years and were using ≥ 3x/week by 17.0 ± 2.3 years. Higher mindfulness scores were associated with fewer cannabis-related problems ( p = 0.004) and fewer quit attempts ( p = 0.035). The number of cannabis-related problems did not significantly mediate the relationship between mindfulness and quit attempts. Trait mindfulness did not predict motivation to change cannabis use.

Conclusions

Among AYAs using cannabis frequently, higher trait mindfulness was associated with both fewer cannabis use-–related problems and fewer quit attempts. Future research should assess whether trait mindfulness is an appropriate target for decreasing cannabis use and the utility of MBIs for reducing cannabis-use behaviors.
State-Led Opioid Overdose Prevention Efforts: Challenges, Solutions and Lessons Learned from the CDC Prevention for States Program (PfS)
Authors: Underwood Natasha , Rooks-Peck Cherie , Ali Nida , Wisdom April , Costa Olga , Robinson Amber , Mells Jamie , Bacon Sarah
Published: April 2021

Background

The Centers for Disease Control and Prevention's Prevention for States (PfS) program funded 29 state health departments to prevent opioid overdose by implementing evidence-based prevention strategies. The objectives of this analysis were to describe the scope of activities implemented across the four PfS strategies and identify implementation challenges.

Methods

PfS recipients submitted annual progress reports (APRs) to state support staff at CDC from 2015 to 2017. APR data were used to calculate the number of required and optional activities implemented under each PfS strategy. APR data were qualitatively analyzed using a systematic content analysis approach to identify key implementation challenges.

Results

From 2015 to 2017, PfS recipients implemented 177 activities across four strategies from 2015 to 2017. Cross-cutting implementation challenges were (1) multi-sector collaboration, (2) lack of knowledge and misperceptions about opioid used disorder (OUD) among some partners and local communities and; (3) management and access to opioid data among PfS recipients.

Conclusions

PfS recipients implemented an array of prevention interventions to address the opioid overdose crisis and encountered several cross-cutting implementation challenges. Challenges and state driven solutions over the course of implementing PfS led to several lessons learned and actions that CDC enacted to continue to support and expand overdose prevention.
Stimulant use for Self-Management of Pain among Safety-Net Patients with Chronic Non-Cancer Pain
Authors: Beliveau Cathleen M. , McMahan Vanessa M. , Arenander Justine , Angst Martin S. , Kushel Margot , Torres Andrea , Santos Glenn-Milo , Coffin Phillip O.
Published: April 2021

Background

Chronic pain affects one-fifth of US adults. Reductions in opioid prescribing have been associated with increased non-prescription opioid use and, chronologically, increased stimulant (methamphetamine and cocaine) use. While non-prescription opioid use is commonly attributed to pain self-management, the role of stimulants in managing pain is unclear.

Methods

We analyzed baseline data from a longitudinal study of patients with chronic non-cancer pain in an urban safety-net healthcare system who had been prescribed an opioid for ≥3 of the last 12 months, and had a history of non-prescription opioid, cocaine, or amphetamine use ( N = 300). We estimated the prevalence and identified correlates of stimulant use to treat pain among a subgroup of patients who reported past-year stimulant use ( N = 105). Data sources included computer-assisted questionnaire (demographics, substance use, pain), clinical exam and procedures (pain, pain tolerance), and chart abstraction (opioid prescriptions). We conducted bivariate analyses to assess associations between demographics, pain characteristics, non-opioid therapies, substance use, opioid prescriptions, and self-reported symptoms, with reporting using stimulants to treat pain. Demographic variables and those with significant bivariate associations were included in a multivariable logistic regression model.

Results

Fifty-two percent of participants with past-year stimulant use reported using stimulants in the past year to treat pain. Participants who used stimulants for pain reported slightly higher average pain in the past 3 months (median of 8 (IQR: 6–8) vs 7 (7–9) out of 10, p = 0.049). In the multivariable analysis, female gender (AOR= 3.20, 95% CI: 1.06–9.63, p = 0.039) and higher score on the Douleur Neuropathique 4 neuropathic pain questionnaire (AOR = 1.34, 95% CI: 1.05–1.70, p = 0.017) were associated with past-year stimulant use to treat pain.

Conclusion

Stimulants may be used for pain self-management, particularly for neuropathic pain and among women. Our findings suggest an underexplored motivation for stimulant use in an era of reduced access to prescribed opioids.
Gambling and Substance Use: A Cross-Consumption Analysis of Tobacco Smoking, Alcohol Drinking and Gambling
Authors: Díaz Alejandro , Pérez Levi
Published: April 2021

Background

Gambling has never been as popular and widely available as it is today. Despite the widespread normalization of gambling as just another form of leisure consumption, its potential interaction with substance use (e.g. smoking and drinking) is nowadays an issue of social concern. In fact, empirical research has found both substances to have strong interdependencies with gambling through multiple factors.

Methods

Gambling is a two-step decision: potential gamblers first decide whether to participate, then their expenditure. Using data from the Spanish gambling prevalence survey, a double-hurdle model is proposed to estimate the effect of tobacco smoking and alcohol drinking on gambling participation and expenditure decisions utilizing binary consumption and frequency of consumption approaches.

Results

In line with previous research, results showed that people who smoked tobacco and/or drank alcohol were more likely to gamble and to have a greater expenditure. Each additional level of frequency of consumption of both products was found to likely increase the prevalence of gambling.

Conclusions

The frequency of consumption of tobacco and/or alcohol was positively associated with the likelihood of gambling and spending more on gambling products. Findings may assist gambling stakeholders to prevent potential gambling-related harm.
Engagement in Perinatal Outpatient Services among Women in Recovery from Opioid use Disorders
Authors: Peacock-Chambers Elizabeth , Paterno Mary T. , Kiely Daniel , Fioroni Tinamarie , Byatt Nancy , Friedmann Peter D.
Published: April 2021

Background

Despite being highly motivated to recover, pregnant and postpartum women with opioid use disorders (OUD) are at high risk of relapse and death. While many services mitigate this risk, engagement in voluntary, outpatient services remains low. Our aim was to understand the experiences of and factors influencing outpatient service engagement during the perinatal period among women in recovery from OUD.

Methods

We conducted semi-structured interviews about perinatal experiences engaging with outpatient services, with 20 women in recovery aged 22–46 years who had children between 6 months and 10 years old. Interviews were audio-recorded, transcribed, coded, and analyzed using conventional content analysis.

Results

Women described a continuum of ‘collaborative engagement’ experiences, defined by the extent to which they perceived their providers or service organizations were invested in their journeys as a partners and advocates. The ability to achieve collaborative engagement depended upon two factors: (1) the woman's transformational development as a mother and woman in recovery, and (2) her perception of the providers’ ability to meet her multifaceted needs.

Conclusions

Women in recovery from OUD may experience deeper engagement in voluntary outpatient perinatal services when they perceive that their providers are invested and collaboratively engaging in their recovery and personal growth. Future research should test whether collaborative engagement improves service retention. Abbreviations: IPV: Intimate Partner Violence; OUD: opioid use disorder
DNA topoisomerase 3 is required for efficient germ cell quality control
Authors: Dello Stritto Maria Rosaria , Bauer Bernd , Barraud Pierre , Jantsch Verena
Published: April 2021

An important quality control mechanism eliminates meiocytes that have experienced recombination failure during meiosis. The culling of defective oocytes in Caenorhabditis elegans meiosis resembles late oocyte elimination in female mammals. Here we show that topoisomerase 3 depletion generates DNA lesions in both germline mitotic and meiotic compartments that are less capable of triggering p53 (cep-1)–dependent apoptosis, despite the activation of DNA damage and apoptosis signaling. Elimination of nonhomologous, alternative end joining and single strand annealing repair factors (CKU-70, CKU-80, POLQ-1, and XPF-1) can alleviate the apoptosis block. Remarkably, the ability of single mutants in the other members of the Bloom helicase-topoisomerase-RMI1 complex to elicit apoptosis is not compromised, and depletion of Bloom helicase in topoisomerase 3 mutants restores an effective apoptotic response. Therefore, uncontrolled Bloom helicase activity seems to direct DNA repair toward normally not used repair pathways, and this counteracts efficient apoptosis. This implicates an as-yet undescribed requirement for topoisomerase 3 in mounting an effective apoptotic response to ensure germ cell quality control.
An APP ectodomain mutation outside of the Aβ domain promotes Aβ production in vitro and deposition in vivo
Authors: Zhang Xulun , Zhang Can Martin , Prokopenko Dmitry , Liang Yingxia , Zhen Sherri Y. , Weigle Ian Q. , Han Weinong , Aryal Manish , Tanzi Rudolph E. , Sisodia Sangram S.
Published: April 2021

Familial Alzheimer’s disease (FAD)–linked mutations in the APP gene occur either within the Aβ-coding region or immediately proximal and are located in exons 16 and 17, which encode Aβ peptides. We have identified an extremely rare, partially penetrant, single nucleotide variant (SNV), rs145081708, in APP that corresponds to a Ser198Pro substitution in exon 5. We now report that in stably transfected cells, expression of APP harboring the S198P mutation (APPS198P) leads to elevated production of Aβ peptides by an unconventional mechanism in which the folding and exit of APPS198P from the endoplasmic reticulum is accelerated. More importantly, coexpression of APP S198P and the FAD-linked PS1ΔE9 variant in the brains of male and female transgenic mice leads to elevated steady-state Aβ peptide levels and acceleration of Aβ deposition compared with age- and gender-matched mice expressing APP and PS1ΔE9. This is the first AD-linked mutation in APP present outside of exons 16 and 17 that enhances Aβ production and deposition.
Ultra-fast and facile preparation of uniform sulfur/graphene composites with microwave for lithium−sulfur batteries
Authors: Sun Zhouting , Jiang Yangchang , Cong Zhi , Zhao Bin , Shen Fei , Han Xiaogang
Published: April 2021

Lithium−sulfur batteries are one of the most promising energy storage systems due to their high energy density. Many efforts have been made to improve the electrochemical performance of lithium−sulfur batteries. However, the complex and time-consuming preparation process hinders their practical application. In this work, an ultra-fast and facile method has been proposed to prepare the sulfur/graphene composites in a simplified and time-saving preparation process with the assistance of microwave. Microwave is introduced to help sulfur fleetly deposit uniformly on the surface of graphene within just 30 s. Nano-sized sulfur within 30 nm is generated in this ultra-fast process. Lithium−sulfur batteries with as-prepared sulfur/graphene composites exhibit good cycling life with a capacity of 503.5 mAh g−1 at 0.2 C. This method makes it possible for lithium−sulfur batteries to be practical.
Exploring the potentiality of future standard candles and standard sirens to detect cosmic opacity *
Authors: Fu Xiangyun , Zhou Lu , Yang Jianfei , Lu Zhen-Yan , Yang Ying , Tang Guo
Published: April 2021

In this work, we explore the potentiality of future gravitational wave (GW) and Type Ia supernovae (SNe Ia) measurements to detect cosmic opacity by comparing the opacity-free luminosity distance (LD) of GW events with the opacity-dependent LD of SNe Ia observations. The GW data are simulated from the future measurements of the ground-based Einstein Telescope (ET) and the space-borne Deci-Herz Interferometer Gravitational wave Observatory (DECIGO). The SNe Ia data are simulated from the observations of the Wide Field Infrared Survey Telescope (WFIRST) that will be collected over the next few decades. A binning method is adopted to match the GW data with the SNe Ia data at the same redshift z with a selection criterion

, and most of the available data from the GW measurements is employed to detect cosmic opacity due to improvements in the distribution of the future SNe Ia observations. Results show that the uncertainties of the constraints on cosmic opacity can be reduced to

and 0.0014 at the

confidence level (CL) for 1000 data points from the ET and DECIGO measurements, respectively. Compared with the allowable limits of intergalactic opacity obtained from quasar continuum observations, these future astronomical observations can be used to verify the cosmic opacity. In this way, GW and SNe Ia measurements can be used as important and effective tools to detect cosmic opacity in the future.
The Impact of Changes in Diagnostic Testing Practices on Estimates of COVID-19 Transmission in the United States
Authors: Pitzer Virginia E , Chitwood Melanie , Havumaki Joshua , Menzies Nicolas A , Perniciaro Stephanie , Warren Joshua L , Weinberger Daniel M , Cohen Ted
Published: April 2021

Estimates of the reproductive number for novel pathogens, such as severe acute respiratory syndrome coronavirus 2, are essential for understanding the potential trajectory of epidemics and the levels of intervention that are needed to bring the epidemics under control. However, most methods for estimating the basic reproductive number (R0) and time-varying effective reproductive number (Rt) assume that the fraction of cases detected and reported is constant through time. We explored the impact of secular changes in diagnostic testing and reporting on estimates of R0 and Rt using simulated data. We then compared these patterns to data on reported cases of coronavirus disease 2019 and testing practices from different states in the United States from March 4, 2020, to August 30, 2020. We found that changes in testing practices and delays in reporting can result in biased estimates of R0 and Rt. Examination of changes in the daily numbers of tests conducted and the percentages of patients who tested positive might be helpful for identifying the potential direction of bias. Changes in diagnostic testing and reporting processes should be monitored and taken into consideration when interpreting estimates of the reproductive number of coronavirus disease.
Is global consequentialism more expressive than act consequentialism?
Authors: Thornley Elliott
Published: April 2021

Act consequentialism states that an act is right if and only if the expected value of its outcome is at least as great as the expected value of any other act’s outcome. Two objections to this view are as follows. The first is that act consequentialism cannot account for our normative ambivalence in cases where agents perform the right act out of bad motives. The second is that act consequentialism is silent on questions of character: questions like ‘What are the right motives to have?’ and ‘What kind of person ought I be?’. These objections have been taken to motivate a move to global consequentialism, on which acts are not the only subjects of normative assessment. Motives and decision-procedures (amongst other things) are also judged right or wrong by direct reference to their consequences. In this paper, I argue that these objections fail to motivate the move from act to global consequentialism.
LRRK2 G2019S mutation amplifies protein aggregate propagation
Authors: Chen Xi , Le Weidong
Published: April 2021

This scientific commentary refers to ‘LRRK2 G2019S kinase activity triggers neurotoxic NSF aggregation’, by Pischedda et al. (doi: 10.1093/brain/awab073).