Test of Equivalence Principle at 10(-8) Level by a Dual-Species Double-Diffraction Raman Atom Interferometer.

We report an improved test of the weak equivalence principle by using a simultaneous 85Rb-87Rb dual-species atom interferometer. We propose and implement a four-wave double-diffraction Raman transition scheme for the interferometer, and demonstrate its ability in suppressing common-mode phase noise of Raman lasers after their frequencies and intensity ratios are optimized. The statistical uncertainty of the experimental data for Eötvös parameter η is 0.8×10(-8) at 3200 s. With various systematic errors corrected, the final value is η=(2.8±3.0)×10(-8). The major uncertainty is attributed to the Coriolis effect.

Agreement between Mycobacterium tuberculosis antigen-based skin test and interferon-gamma release assay in elderly individuals aged ≥ 65 years in China.

OBJECTIVES: To determine the agreement of Mycobacterium tuberculosis (MTB) antigen-based skin test (TBST) with interferon-gamma release assay (IGRA) in elderly individuals aged ≥ 65 years beyond instruction for use in China. METHODS: Based on the baseline survey of randomized controlled trial with objective to explore suitable regimen for tuberculosis (TB) preventive treatment, MTB infection was tested using TBST and IGRA in parallel in rural residents aged 50-70 years by means of a cross-sectional study design. RESULTS: A total of 21219 participants with both TBST and IGRA results were included in this analysis. The concordance between TBST and IGRA was 89.4% (95%CI: 89.0 - 89.8%) with a kappa coefficient of 0.61 (95%CI: 0.60 - 0.62). In those aged ≥ 65 years, the concordance was 86.5% (95%CI: 85.6 - 87.4%) with a kappa coefficient of 0.55 (95%CI: 0.52 - 0.58). 21.2% (35/165) of the participants with indeterminate IGRA results were TBST positive, and 9 of them aged ≥ 65 years. CONCLUSIONS: The consistent agreement between TBST and IGRA in individuals aged ≥ 65 years suggests that TBST has potential to be used in the elderly with age beyond instruction for use in China. The respective diagnostic performance of each test will be analyzed when the longitudinal data on incident TB be obtained in the future.

CD8+ T cell response in QuantiFERON-TB Gold Plus testing was associated with tuberculosis recurrence: a 2-year prospective study.

BACKGROUND: Recurrence posed an important challenge to pulmonary tuberculosis (PTB) control in China. The prospective study aimed to identify potential risk factors and to explore the value of QuantiFERON-TB Gold Plus (QFT-Plus) in identifying at-risk individuals with treated prior PTB history. METHODS: All eligible individuals aged ≥18 years who had been diagnosed with PTB before 2016 in Zhongmu County, where with an average level of TB prevalence in China, were included and received baseline survey including chest radiography, QuantiFERON-TB Gold In-Tube (QFT-GIT) and QFT-Plus, then PTB recurrence was tracked through a 2-year follow-up. RESULTS: Half of 1068 (52.34%, 559/1068) included eligible participants were QFT-Plus positive at baseline and 21 of them recurred active TB in 2-year follow-up. Individuals aged ≥ 60 years, who had a recent history of TB and smokers were associated with increased risk of TB recurrence with an adjusted odds ratio (aOR) of 3.97 (95% confidence interval (CI): 1.29-12.24), 7.71 (95% CI: 1.74-34.25) and 4.56 (95% CI: 1.62-12.83), respectively. Compared to QFT-Plus negatives, those who were TB2+/TB1- (aOR = 15.34) exhibited stronger association with the risk of TB recurrence than those who were TB1+/TB2+ (aOR = 6.06). A dose response relationship was also found between the risk of TB recurrence with the baseline level of TB2-TB1 (p for trend < 0.001). CONCLUSIONS: High burden of TB infection and high risk of PTB recurrence were observed in the study population. Those with recent onset of prior TB, elderly smokers and QFT-Plus positives especially with TB2 single positive deserved further attention in active TB surveillance.

An actively compensated 8 nT-level magnetic shielding system for 10-m atom interferometer.

We design and develop a high-performance magnetic shielding system for a long baseline fountain-type atom interferometer. The shielding system is achieved by a combination of passive shielding using permalloy and active compensation with coils. An 11.4 m-long three-layer cylindrical shield is completed by the process of welding, local annealing, and entire annealing. The active compensations compress the residual magnetic field to 8.0 nT max-to-min and the corresponding gradient below 30 nT/m over 10 m along the axial direction in which external compensation, internal compensation, and constant magnetic field (C-field) compensation reduce the inhomogeneities to 25.0, 12.6, and 1.7 nT (standard deviation) sequentially. We estimate that this system could reduce the systematic error of the quadratic Zeeman shift to the 10-13 level for the weak equivalence principle test with a simultaneous 85Rb-87Rb dual-species atom interferometer.