Imaging Fluorescence of He_{2}^{*} Excimers Created by Neutron Capture in Liquid Helium II

We show unequivocal evidence for formation of He_{2}^{*} excimers in liquid He II created by ionizing radiation produced through neutron capture. Laser beams induce fluorescence of the excimers. The fluorescence is recorded at a rate of 55.6 Hz by a camera. The location of the fluorescence is determined with an uncertainty of 5  μm. The technique provides an opportunity to record the flow of He_{2}^{*} excimers in a medium with very small viscosity and enables measurement of turbulence around macroscopic liter size objects or vortex matter in three dimensions.

Real-time quantification of damage in structural materials during mechanical testing

A novel methodology is introduced for quantifying the severity of damage created during testing in composite components. The method uses digital image correlation combined with image processing techniques to monitor the rate at which the strain field changes during mechanical tests. The methodology is demonstrated using two distinct experimental datasets, a ceramic matrix composite specimen loaded in tension at high temperature and nine polymer matrix composite specimens containing fibre-waviness defects loaded in bending. The changes in the strain field owing to damage creation are shown to be a more effective indicator that the specimen has reached its proportional limit than using load-extension diagrams. The technique also introduces a new approach to using experimental data for creating maps indicating the spatio-temporal distribution of damage in a component. These maps indicate where damage occurs in a component, and provide information about its morphology and its time of occurrence. This presentation format is both easier and faster to interpret than the raw data which, for some tests, can consist of tens of thousands of images. This methodology has the potential to reduce the time taken to interpret large material test datasets while increasing the amount of knowledge that can be extracted from each test.

Centralized pain and pain catastrophizing mediate the association between lifetime abuse history and self-reported pain medication side effects

Background

Self-reported side effects of pain medication are important determinants of treatment course that can affect patient adherence, medication discontinuation and physician decisions. Yet, few studies have investigated patient-level predictors of self-reported pain medication side effects. The present study sought to fill this gap by exploring the impact of physical or sexual abuse history on self-reported pain medication side effects and considered a mediation model in which those effects are transmitted through a centralized pain phenotype and pain catastrophizing.

Methods

We conducted a cross-sectional analysis of 3118 patients presenting to a tertiary-care, outpatient pain clinic.

Results

Approximately 15% of the sample (n=479) reported a lifetime history of abuse. Patients with a lifetime history of abuse, particularly abuse that occurred in both childhood and adulthood, reported more pain medication side effects compared with patients reporting no abuse history. Furthermore, path analysis showed that a centralized pain phenotype and pain catastrophizing mediated the association between lifetime abuse history and the sum of pain medication side effects.

Conclusions

This suggests that individuals who experience abuse may develop a heightened physiological sensitivity to stimuli, as well as a tendency to interpret stimuli negatively, exaggerate the impact of aversive stimuli and undermine their ability to cope with the stressor. This study highlights the need for physicians to understand patient-level predictors of medication tolerance and to consider a history of abuse and trauma in decisions regarding treatment and medication management.

Initial validation of the electronic form of the Michigan Body Map

BACKGROUND

The Michigan Body Map (MBM) was developed to assess pain location in a reliable and valid manner; however, electronic formats have not been validated. This study had two aims: (1) initial validation of the electronic form of the MBM (eMBM) and (2) preliminary test of assessing pain severity within body zones.

METHODS

For the first aim, 68 participants with chronic pain completed paper and electronic forms of the MBM, then underwent scripted interviews to assess preferences among body maps and verbal confirmation of pain locations. For the second aim, a subset of the participants (n=40) completed the Brief Pain Inventory (BPI) pain severity subscale, as well as the eMBM again and endorsed pain severity using additional screens showing body zones that contained areas in which pain was endorsed.

RESULTS

There were few discrepancies between MBM, eMBM and verbal report (1.9% and 1.6%, respectively), and no difference between forms in perceived ability to indicate areas of pain or ease of completion. Patients accurately indicated their bodily pain on both maps, with 84% and 87% reporting one or no errors on MBM and eMBM, respectively. Participants also reported no preference for which version best-depicted areas of pain or best distinguished left from right. Lastly, the most preferred measure was eMBM with pain severity zones, followed by eMBM without zones, followed by the BPI pain severity subscale.

CONCLUSIONS

These data support the validity of the eMBM for patients with chronic pain. Further, an expanded form of the eMBM that assesses pain severity was preferred by most participants.

The Nab experiment: A precision measurement of unpolarized neutron beta decay

Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ = gA/gV, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter a with a precision of δa/a = 10−3 and the Fierz interference term b to δb = 3 × 10−3 in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ with a precision of δλ/λ = 0.03% that will allow an evaluation of Vud and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.

A small proton charge radius from an electron-proton scattering experiment

Elastic electron-proton scattering (e-p) and the spectroscopy of hydrogen atoms are the two methods traditionally used to determine the proton charge radius, r_p. In 2010, a new method using muonic hydrogen atoms¹ found a substantial discrepancy compared with previous results², which became known as the 'proton radius puzzle'. Despite experimental and theoretical efforts, the puzzle remains unresolved. In fact, there is a discrepancy between the two most recent spectroscopic measurements conducted on ordinary hydrogen^3,4. Here we report on the proton charge radius experiment at Jefferson Laboratory (PRad), a high-precision e-p experiment that was established after the discrepancy was identified. We used a magnetic-spectrometer-free method along with a windowless hydrogen gas target, which overcame several limitations of previous e-p experiments and enabled measurements at very small forward-scattering angles. Our result, r_p = 0.831 ± 0.007_stat ± 0.012_syst femtometres, is smaller than the most recent high-precision e-p measurement⁵ and 2.7 standard deviations smaller than the average of all e-p experimental results⁶. The smaller r_p we have now measured supports the value found by two previous muonic hydrogen experiments^1,7. In addition, our finding agrees with the revised value (announced in 2019) for the Rydberg constant⁸-one of the most accurately evaluated fundamental constants in physics.

A dataset on human perception of and response to wildfire smoke

Wildfire smoke presents a growing threat in the Western U.S.; and human health, transportation, and economic systems in growing western communities suffer due to increasingly severe and widespread fires. While modelling wildfire activity and associated wildfire smoke distributions have substantially improved, understanding how people perceive and respond to emerging smoke hazards has received little attention. Understanding and incorporating human perceptions of threats from wildfire smoke is critical, as decision-makers need such information to mitigate smoke-related hazards. We surveyed 614 randomly selected people (in-person) across the Boise Metropolitan Area in Idaho and 1,623 Boise State University affiliates (online), collecting information about their level of outside activity during smoke event(s), knowledge about the source of air quality information and effective messaging preference, perception of wildfire smoke as a hazard, and smoke-related health experiences. This relatively large dataset provides a novel perspective of people's perception of smoke hazards, and provides crucial policy-relevant information to decision-makers. Dataset is available to the public and can be used to address a wide range of research questions.

Phenotypic features of patients with complex regional pain syndrome compared with those with neuropathic pain

INTRODUCTION

We hypothesized that patients with complex regional pain syndrome (CRPS) would describe a more negative pain phenotype including higher pain severity, more neuropathic pain descriptors, more centralized pain symptoms, poorer physical function, and more affective distress when compared with patients with neuropathic pain of the extremities not meeting CRPS criteria.

MATERIALS AND METHODS

This was a retrospective cross-sectional study conducted at a tertiary pain center. The sample included 212 patients who met Budapest Criteria for CRPS and 175 patients with neuropathic pain of the extremities who did not meet criteria. All patients completed a packet of questionnaires before their initial visit containing validated outcome measures assessing pain severity, pain interference, physical functioning, depression, anxiety, and catastrophizing.

RESULTS

Patients with CRPS reported higher physical disability (p=0.022) and more neuropathic pain symptoms (p=0.002) than patients not meeting CRPS criteria, but the groups did not otherwise differ significantly. There were no significant differences in pain severity or affective distress, despite power analyses suggesting the ability to detect small to medium effect sizes (d=0.29; w=0.14). Subanalyses of differences in neuropathic pain symptoms revealed that patients with CRPS, compared with patients not meeting CRPS criteria, were more likely to report pain with light touch (p=0.003), sudden pain attacks (p=0.003), pain with cold or heat (p=0.002), sensation of numbness (p=0.042), and pain with slight pressure (p=0.018).

DISCUSSION

Counter to our hypothesis, the present study suggests that patients with CRPS do not have a worse clinical phenotype compared with patients not meeting CRPS criteria, with the exception of higher physical disability and more neuropathic pain symptoms. This corresponds to recent evidence that patients with CRPS are similar to other patient populations with chronic pain.

Purpose and mastery as predictors of perceived health and substance use problems

We explored whether purpose in life and mastery predicted perceived physical health and problematic substance use among a sample of emerging adults who reported ever using alcohol or drugs. We examined perceived stress and coping as potential mediators of these associations and explored whether parental support moderated any of these associations. In a sample of emerging adults from across the United States (N = 2,564; M _age  = 20.87, standard deviation  = 1.75; 49.6% male), purpose in life and mastery were associated with better-perceived health and fewer negative consequences of drug use via lower perceived stress and coping. In addition, parental support modified the relationship between purpose in life and stress and coping. The findings suggest potential health benefits associated with a greater purpose in life and mastery and indicate that parental support may enhance these associations.

Prognostic value of circulating tumour cells in limited-stage small-cell lung cancer: analysis of the concurrent once-daily versus twice-daily radiotherapy (CONVERT) randomised controlled trial

BACKGROUND

The clinical significance of circulating tumour cells (CTCs) in limited-stage small-cell lung cancer (LS-SCLC) is not well defined. We report a planned exploratory analysis of the prevalence and prognostic value of CTCs in LS-SCLC patients enrolled within the phase III randomised CONVERT (concurrent once-daily versus twice-daily chemoradiotherapy) trial.

PATIENTS AND METHODS

Baseline blood samples were enumerated for CTCs using CellSearch in 75 patients with LS-SCLC who were enrolled in the CONVERT trial and randomised between twice- and once-daily concurrent chemoradiation. Standard statistical methods were used for correlations of CTCs with clinical factors. Log-rank test and Cox regression analyses were applied to establish the associations of 2, 15 and 50 CTC thresholds with progression-free survival (PFS) and overall survival (OS). An optimal CTC count threshold for LS-SCLC was established.

RESULTS

CTCs were detected in 60% (45/75) of patients (range 0-3750). CTC count thresholds of 2, 15 and 50 CTCs all significantly correlate with PFS and OS. An optimal CTC count threshold in LS-SCLC was established at 15 CTCs, defining 'favourable' and 'unfavourable' prognostic risk groups. The median OS in <15 versus ≥15 CTCs was 26.7 versus 5.9 m (P = 0.001). The presence of ≥15 CTCs at baseline independently predicted ≤1 year survival in 70% and ≤2 years survival in 100% of patients.

CONCLUSION

We report the prognostic value of baseline CTC count in an exclusive LS-SCLC population at thresholds of 2, 15 and 50 CTCs. Specific to LS-SCLC, ≥15 CTCs was associated with worse PFS and OS independent of all other factors and predicted ≤2 years survival. These results may improve disease stratification in future clinical trial designs and aid clinical decision making.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00433563.

First Measurements of the Double-Polarization Observables F, P, and H in ω Photoproduction off Transversely Polarized Protons in the N^{*} Resonance Region

First measurements of double-polarization observables in ω photoproduction off the proton are presented using transverse target polarization and data from the CEBAF Large Acceptance Spectrometer (CLAS) FROST experiment at Jefferson Lab. The beam-target asymmetry F has been measured using circularly polarized, tagged photons in the energy range 1200-2700 MeV, and the beam-target asymmetries H and P have been measured using linearly polarized, tagged photons in the energy range 1200-2000 MeV. These measurements significantly increase the database on polarization observables. The results are included in two partial-wave analyses and reveal significant contributions from several nucleon (N^{*}) resonances. In particular, contributions from new N^{*} resonances listed in the Review of Particle Properties are observed, which aid in reaching the goal of mapping out the nucleon resonance spectrum.

Salivary uric acid: Associations with resting and reactive blood pressure response to social evaluative stress in healthy African Americans

High levels of uric acid are associated with greater risk of stress-related cardiovascular illnesses that occur disproportionately among African Americans. Whether hyperuricemia affects biological response to acute stress remains largely unknown, suggesting a need to clarify this potential connection. The current study examined how salivary uric acid (sUA) is associated with resting and reactive blood pressure - two robust predictors of hypertension and related cardiovascular disease and disparity. Healthy African Americans (N = 107; 32% male; M age = 31.74 years), completed the Trier Social Stress Test to induce social-evaluative stress. Systolic and diastolic blood pressure readings were recorded before, during, and after the task to assess resting and reactive change in blood pressure. Participants also provided a saliva sample at baseline that was assayed for sUA. At rest, and controlling for age, sUA was modestly associated with higher systolic (r = .201, p =  .044), but not diastolic (r = .100, p =  .319) blood pressure. In response to the stressor task, and once again controlling for age, sUA was also associated with higher total activation of both systolic (r = .219, p =  .025) and diastolic blood pressure (r = .198, p <  .044). A subsequent moderation analysis showed that associations between sUA and BP measures were significant for females, but not for males. Findings suggest that uric acid may be implicated in hypertension and cardiovascular health disparities through associations with elevated blood pressure responses to acute social stress, and that low levels of uric acid might be protective, particularly for females.

Primary Anterolateral Ligament Rupture in Patients Requiring Revision Anterior Cruciate Ligament Reconstruction: A Retrospective Case-Control Magnetic Resonance Imaging Review

PURPOSE

To compare the initial rate of anterolateral ligament (ALL) injury at the time of anterior cruciate ligament (ACL) rupture in patients who subsequently experienced ACL reconstruction graft failure versus patients who did not experience subsequent ACL reconstruction graft failure.

METHODS

Our institution's electronic medical record database was queried for patients who underwent primary ACL reconstruction with subsequent ACL graft rupture. Exclusion criteria included unavailable MRI scan, chronic ACL injury, multi-ligamentous injury, previous ACL reconstruction, and age younger than 13 or older than 50 years. Each patient was paired with an age-, gender-, and graft-matched control who underwent ACL reconstruction without subsequent graft rupture. Each patient was diagnosed with an intact, partially injured, or fully ruptured ALL on initial MRI. The location of ALL injury was also noted. The incidence and location of ALL rupture were compared using χ² analysis.

RESULTS

1,967 patients underwent primary ACL reconstruction. 128 patients experienced ACL graft rupture, and 55 patients (43%) had MRI scans available for review. 39 of these patients fulfilled inclusion criteria and were matched with a control patient. In the revision group, the ALL was diagnosed as intact, partially torn, and completely torn in 17, 14, and 8 patients, respectively, compared to 18, 13, and 8 patients, respectively in the control group. No difference was found in frequency of ALL rupture (Pearson χ² = 0.066; P = .968) or rupture location (Pearson χ² = 4.00, P = 0.135).

CONCLUSIONS

The incidence of initial ALL injury as documented on MRI was not different in patients who experienced subsequent ACL graft rupture compared with patients who did not experience ACL graft rupture after primary ACL reconstruction. The ALL was more commonly injured on the tibial side in patients with ACL graft rupture and femoral-sided lesions were more common in control patients.

LEVEL OF EVIDENCE

Level III, prognostic case-control study.

Justice for all? Beliefs about justice for self and others and telomere length in African Americans

OBJECTIVE

Believing in justice can protect health. Among marginalized racial minorities however, both endorsing and rejecting beliefs about justice might be critical. The current research examined links between African Americans' beliefs about justice for self and for others and telomere length (TL)-an indicator of biological aging that is increasingly implicated in racial health disparities, with shorter telomeres indicating poorer health.

METHOD

Healthy African Americans (N = 118; 30% male; M age = 31.63 years) completed individual differences measures of justice beliefs for self and others and then provided dried blood spot samples that were assayed for TL.

RESULTS

We expected that a belief in justice for self would be positively associated with TL, whereas a belief in justice for others would be negatively associated. A significant 3-way interaction with chronological age confirmed this hypothesis-among older African Americans, TL was positively associated with believing in justice for self, but only when this belief was accompanied by a weak endorsement of the belief in justice for others.

CONCLUSION

Findings underscore that for racial minorities, health might be best protected when justice beliefs are both endorsed and rebuffed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Measurement of the Q^{2} Dependence of the Deuteron Spin Structure Function g_{1} and its Moments at Low Q^{2} with CLAS

We measured the g_{1} spin structure function of the deuteron at low Q^{2}, where QCD can be approximated with chiral perturbation theory (χPT). The data cover the resonance region, up to an invariant mass of W≈1.9  GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Γ_{1}^{d} and the spin polarizability γ_{0}^{d} are precisely determined down to a minimum Q^{2} of 0.02  GeV^{2} for the first time, about 2.5 times lower than that of previous data. We compare them to several χPT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χPT domain.

Mediators of the Association Between Childhood Emotional Maltreatment and Young Adult Men's Life Satisfaction

Childhood emotional maltreatment has been linked to a wide range of deleterious physical and psychological adult health outcomes. The present study extends past research by examining the effects of childhood emotional maltreatment on young adult men's life satisfaction through its effects on hostility and perceptions of social relationships. Participants were 423 single men who completed two interviews 1 year apart. As hypothesized, the association between self-reported childhood emotional maltreatment and adult life satisfaction was mediated through general hostility, rejection sensitivity in romantic relationships, and perceptions of male friends' social support. These findings suggest that interventions which address distorted perceptions of romantic partners and friends might reduce the negative impact of childhood emotional maltreatment.

Will Clean Air Fade Away?

Government-sponsored research and regulations enabled western U.S. states to clean up their air, despite industrial and population growth. Proposed funding cuts could undo this progress.

Telomere length and procedural justice predict stress reactivity responses to unfair outcomes in African Americans

This experiment demonstrates that chromosomal telomere length (TL) moderates response to injustice among African Americans. Based on worldview verification theory - an emerging psychosocial framework for understanding stress - we predicted that acute stress responses would be most pronounced when individual-level expectancies for justice were discordant with justice experiences. Healthy African Americans (N=118; 30% male; M age=31.63years) provided dried blood spot samples that were assayed for TL, and completed a social-evaluative stressor task during which high versus low levels of distributive (outcome) and procedural (decision process) justice were simultaneously manipulated. African Americans with longer telomeres appeared more resilient (in emotional and neuroendocrine response-higher DHEAs:cortisol) to receiving an unfair outcome when a fair decision process was used, whereas African Americans with shorter telomeres appeared more resilient when an unfair decision process was used. TL may indicate personal histories of adversity and associated stress-related expectancies that influence responses to injustice.