Mapping the amplitude and phase of dissolved 129 Xe red blood cell signal oscillations with keyhole spectroscopic lung imaging

Purpose To assess the regional amplitude and phase of dissolved 129Xe red blood cell (RBC) signal oscillations in the lung vasculature with keyhole spectroscopic imaging and to compare with previous methodology, which does not account for oscillation phase. Methods 129Xe gas transfer was measured with a four-echo 3D radial spectroscopic imaging sequence. Keyhole reconstruction-based RBC signal oscillation amplitude mapping was applied retrospectively to data acquired from 28 healthy volunteers, 4 chronic thromboembolic pulmonary hypertension (CTEPH) patients, and 5 patients who were hospitalized due to COVID-19 pneumonia and had residual lung abnormalities. Using a sliding window keyhole reconstruction, maps of RBC oscillation amplitude were corrected for regional phase difference. Repeatability of the phase-adjusted oscillation amplitude was assessed in 8 healthy volunteers across three scans. Results With sliding window keyhole reconstruction, regional phase differences were observed in the RBC signal oscillations: mean phase = (0.27 ± 0.19) rad in healthy volunteers, (0.24 ± 0.13) rad in CTEPH patients, and (0.33 ± 0.19) rad in patients with post-COVID-19 residual lung abnormality. The oscillation amplitude and phase maps were more heterogeneous (i.e., they showed increased coefficient of variation) for the CTEPH patients. The RBC oscillation amplitude was repeatable, and the mean three-scan coefficient of variation was smaller when the phase adjustment was made (0.07 ± 0.04 compared with 0.16 ± 0.05). Conclusion Sliding window keyhole reconstruction of radial dissolved 129Xe imaging reveals regional phase differences in the RBC oscillations, which are not captured when performing two phase keyhole reconstruction. This regional phase information may reflect the hemodynamic effect of the cardiac pulse wave in the pulmonary microvasculature

Exawatt-Zettawatt Pulse Generation and Applications

A new amplification method, weaving the three basic compression techniques, Chirped Pulse Amplification (CPA), Optical Parametric Chirped Pulse Amplification (OPCPA) and Plasma Compression by Backward Raman Amplification (BRA) in plasma, is proposed. It is called C3 for Cascaded Conversion Compression. It has the capability to compress with good efficiency kilojoule to megajoule, nanosecond laser pulses into femtosecond pulses, to produce exawatt and beyond peak power. In the future, C3 could be used at large-scale facilities such as the National Ignition Facility (NIF) or the Laser Megajoule (LMJ) and open the way to zettawatt level pulses. The beam will be focused to a wavelength spot size with a f#1. The very small beam size, i.e. few centimeters, along with the low laser repetition rate laser system will make possible the use of inexpensive, precision, disposable optics. The resulting intensity will approach the Schwinger value, thus opening up new possibilities in fundamental physics.Comment: 13 pages, 4 figure

Longitudinal lung function assessment of patients hospitalised with COVID-19 using 1H and 129Xe lung MRI

BACKGROUND: Microvascular abnormalities and impaired gas transfer have been observed in patients with COVID-19. The progression of pulmonary changes in these patients remains unclear. RESEARCH QUESTION: Do patients hospitalised due to COVID-19 without evidence of architectural distortion on structural imaging show longitudinal improvements in lung function measured using 1H and 129Xe magnetic resonance imaging between 6-52 weeks after hospitalisation? STUDY DESIGN AND METHODS: Patients who were hospitalised due to COVID-19 pneumonia underwent a pulmonary 1H and 129Xe MRI protocol at 6, 12, 25 and 51 weeks after hospital admission in a prospective cohort study between 11/2020 and 02/2022. Imaging protocol: 1H ultra-short echo time, contrast enhanced lung perfusion, 129Xe ventilation, 129Xe diffusion weighted and 129Xe spectroscopic imaging of gas exchange. RESULTS: 9 patients were recruited (57±14 [median±interquartile range] years, 6/9 male). Patients underwent MRI at 6 (N=9), 12 (N=9), 25 (N=6) and 51 (N=8) weeks after hospital admission. Patients with signs of interstitial lung damage were excluded. At 6 weeks, patients demonstrated impaired 129Xe gas transfer (red blood cell to membrane fraction) but lung microstructure was not increased (apparent diffusion coefficient and mean acinar airway dimensions). Minor ventilation abnormalities present in four patients were largely resolved in the 6-25 week period. At 12 weeks, all patients with lung perfusion data (N=6) showed an increase in both pulmonary blood volume and flow when compared to 6 weeks, though this was not statistically significant. At 12 weeks, significant improvements in 129Xe gas transfer were observed compared to 6-week examinations, however 129Xe gas transfer remained abnormally low at weeks 12, 25 and 51. INTERPRETATION: 129Xe gas transfer was impaired up to one year after hospitalisation in patients who were hospitalised due to COVID-19 pneumonia, without evidence of architectural distortion on structural imaging, whereas lung ventilation wa normal at 52 weeks

Self-Compassion as a Compensatory Resilience Factor for the Negative Emotional Outcomes of Alcohol- Involved Sexual Assault among Undergraduates

Objectives: Approximately half of sexual assaults involve alcohol; these assaults tend to be more severe and may be more likely to result in negative emotional outcomes like anxiety and depression (Ullman & Najdowski, 2010). Self-compassion (SC; extending kindness and care towards oneself) may promote resilience from the negative emotional consequences of alcohol-involved sexual assault (AISA). This study examined SC as a resilience factor, testing whether it attenuates and/or counteracts the association between AISA and negative emotional outcomes. Methods: Undergraduate drinkers (N = 785) completed measures tapping past-term AISA (Kehayes, et al., 2019), SC (i.e., Self-Compassion Scale; Neff, 2003), and anxiety and depression (Kessler et al., 2002). The Self-Compassion Scale was scored as two higherorder domains (self-caring, self-criticism) each with three lower-order facets (self-kindness, mindfulness, and common humanity; over-identification, self-judgment, and isolation). Results: Supporting compensatory effects, the higher-order SC domains showed main effects: the presence of self-caring and relative absence of self-criticism counteracted the adverse effects of AISA on both anxiety and depression. Similarly, the lower-order SC facets showed main effects: the presence of self-kindness and relative absence of overidentification counteracted the adverse effects of AISA on anxiety/depression – with therelative absence of self-judgment and isolation additionally counteracting the effect of AISA on depression. Conclusion: SC works as a compensatory resilience factor for the association between AISA and anxiety/depression. Implications: SC interventions with attention towards increasing self-kindness and decreasing negative facets of SC may be important for negative emotional outcomes in general, including those following AISA

Progression of impairment in adolescents with attention-deficit/hyperactivity disorder through the transition out of high school: Contributions of parent involvement and college attendance

Long-term, prospective follow-up studies of children diagnosed with Attention-Deficit/Hyperactivity Disorder (ADHD) show that symptoms tend to decline with age, but impairments in daily life functioning often persist into adulthood. We examined the developmental progression of impairments before and after the transition out of high school in relation to parent involvement during adolescence, parent support during adulthood, and college attendance, using 8 waves of data from the prospective 16-year follow-up of the Multimodal Treatment of ADHD (MTA) Study. Participants were 548 proband children diagnosed with DSM-IV ADHD Combined Type and 258 age- and sex-matched comparison children (Local Normative Comparison Group; LNCG) randomly sampled from probands' schools. Impairment was assessed consistently by parent report from childhood through adulthood. Results showed that impairment worsens over time both before and after the transition to adulthood for those with ADHD histories, in contrast to non-ADHD peers, whose impairments remained stably low over time. However, impairment stabilized after leaving high school for young adults with ADHD histories who attended college. Involved parenting in adolescence was associated with less impairment overall. Attending college was associated with a stable post-high school trajectory of impairment regardless of parents' involvement during adolescence, but young adults with histories of involved parenting and who attended college were the least impaired overall