Laser Spectroscopic Measurement of Helium Isotope Ratios

A sensitive laser spectroscopic method has been applied to the quantitative determination of the isotope ratio of helium at the level of 3He/4He = 10^-7 - 10^-5. The resonant absorption of 1083 nm laser light by the metastable 3He atoms in a discharge cell was measured with the frequency modulation saturation spectroscopy technique while the abundance of 4He was measured by a direct absorption technique. The results on three different samples extracted from the atmosphere and commercial helium gas were in good agreement with values obtained with mass spectrometry. The achieved 3-sigma detection limit of 3He in helium is 4 x 10^-9. This demonstration required a 200 micro-L STP sample of He. The sensitivity can be further improved, and the required sample size reduced, by several orders of magnitude with the addition of cavity enhanced spectroscopy

THE EFFECTS OF MUSCLE CROSS-SECTIONAL AREA ON THE PHYSICAL WORKING CAPACITY AT THE FATIGUE THRESHOLD

Purpose: The purpose of this study was to examine the effects of quadriceps cross-sectional area (CSA) of the dominant quadriceps muscle in the assessment of the physical working capacity at the fatigue threshold (PWCFT) during incremental cycle ergometry. Methods: Eighteen adults (9 men and 9 women; mean age ± SD = 20.5 ± 1.04 yr; mean body weight ± SD = 73.9 ± 18.2 kg; mean height ± SD = 172.3 ± 11.5 cm; mean dominant quadriceps CSA ± SD = 68.7 ± 14.5 cm2) performed an incremental cycle ergometry test to exhaustion while the electromyographic (EMG) signals were recorded from the vastus lateralis (VL) muscles. Fatiguing and non-fatiguing power outputs were differentiated by examining the slope coefficients for the EMG amplitude versus time relationship at each power output throughout the incremental cycle ergometry test. Quadriceps CSA was estimated from an equation. Subjects were divided into groups of small quadriceps CSA (57.3 ± 10.0 cm2) and large quadriceps CSA (80.0 ± 7.6 cm2). Results: Independent t-test results indicated no significant mean differences between the PWCFT for the large and small quadriceps CSA groups (p=0.456). Conclusion: The findings of the study suggest that muscle CSA may not have a significant effect on the assessment of the PWCFT, and therefore that PWCFT may be a determinant of neuromuscular fatigue independent of muscle CSA. Future research could explore the contributions of muscle fibertype predominance to CSA and PWCFT and provide more conclusive evidence relating these variables

Studying Children's Intrapersonal Emotion Regulation Strategies from the Process Model of Emotion Regulation

peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=vgnt2

Cross-oncopanel study reveals high sensitivity and accuracy with overall analytical performance depending on genomic regions

BackgroundTargeted sequencing using oncopanels requires comprehensive assessments of accuracy and detection sensitivity to ensure analytical validity. By employing reference materials characterized by the U.S. Food and Drug Administration-led SEquence Quality Control project phase2 (SEQC2) effort, we perform a cross-platform multi-lab evaluation of eight Pan-Cancer panels to assess best practices for oncopanel sequencing.ResultsAll panels demonstrate high sensitivity across targeted high-confidence coding regions and variant types for the variants previously verified to have variant allele frequency (VAF) in the 5-20% range. Sensitivity is reduced by utilizing VAF thresholds due to inherent variability in VAF measurements. Enforcing a VAF threshold for reporting has a positive impact on reducing false positive calls. Importantly, the false positive rate is found to be significantly higher outside the high-confidence coding regions, resulting in lower reproducibility. Thus, region restriction and VAF thresholds lead to low relative technical variability in estimating promising biomarkers and tumor mutational burden.ConclusionThis comprehensive study provides actionable guidelines for oncopanel sequencing and clear evidence that supports a simplified approach to assess the analytical performance of oncopanels. It will facilitate the rapid implementation, validation, and quality control of oncopanels in clinical use.Peer reviewe

AN ANALYSIS OF FACTORS IN INTERUNIT MANAGEMENT AND GOVERNANCE INFLUENCINGIMPACT OF TEACHER CORPS PROGRAMS.

Abstract not availabl