bluuebunny/crossref_metadata_2025_split huggingface dataset:
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
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

Abstract
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.