The role of Xpert MTB/RIF using bronchoalveolar lavage fluid in active screening: insights from a tuberculosis outbreak in a junior school in eastern China.

Background: Tuberculosis (TB) outbreaks in schools present a public health challenge. In order to effectively control the spread of transmission, timely screening, accurate diagnosis and comprehensive epidemiological investigations are essential. Methods: In July 2021, a TB outbreak occurred in a junior high school in Y City, Zhejiang Province. Students and faculty were screened for TB by symptom screening, chest radiography, and tuberculin skin test during four rounds of contact screenings. For sputum smear-negative and sputum-scarce patients, bronchoscopy was used to collect BAL samples for Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF). Whole-genome sequencing and bioinformatics analysis were performed on isolates to identify the strains of MTB isolates and predict drug resistance. Results: Between July 2021 and November 2021, a total of 1,257 students and faculty were screened for TB during screenings. A total of 15 students (1.2% of persons screened) aged 15 years were diagnosed with TB. Eighty percent (12/15) of the cases were laboratory-confirmed (10/12 [83%] Xpert MTB/RIF-positive, 2/12 [17%] culture-positive). Most cases (12/15 [80%]) were in students from Class 2. All cases were asymptomatic except for the index case who had symptoms for more than two months. Seven MTB isolates were collected and belonged to lineage 2. Conclusion: Our findings demonstrated the potential of Xpert MTB/RIF using BAL as a screening tool in school TB outbreaks for sputum smear-negative and sputum-sparse suspects, which may not only rapidly improves diagnostic accuracy, but also facilitates epidemiological investigations and homology analysis.

Approaching charge balance in organic light-emitting diodes by tuning charge injection barriers with mixed monolayers.

Self-assembled monolayers (SAMs) of binary mixtures of 1-butylphosphonic acid and the trifluoromethyl-terminated analogue (4,4,4-trifluoro-1-butylphosphonic acid) were formed on ITO surfaces to tune the work function of ITO over a range of 5.0 to 5.75 eV by varying the mixing ratio of the two adsorbents. The mixed SAM-modified ITO surfaces were used as the anode in the fabrication of OLED devices with a configuration of ITO/SAM/HTL/Alq3/MX/Al, where HTL was the NPB or BPAPF hole-transporting layer and MX was the LiF or Cs(2)CO(3) injection layer. It was shown that, depending on the HTL or MX used, the maximum device current and the maximum luminance efficiency occurred with anodes of different modifications because of a shift in the point of hole/electron carrier balance. This provides information on the charge balance in the device and points to the direction to improve the performance.

Continuous modulation of electrode work function with mixed self-assembled monolayers and its effect in charge injection.

Self-assembled monolayers (SAMs) of binary mixtures of n-decanethiol and the fluorinated analogue (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-1-decanethiol) were formed on silver surface. The film structure was characterized by reflection absorption IR and XPS to be a homogeneous mixture of the two components. The mixed monolayers serve to tune the work function of silver over a wide range by varying the surface composition of the mixed monolayer from 4.1 to 5.8 eV. The mixed SAM-modified Ag surfaces were used as the anode in the fabrication of hole-only devices with the device structure Ag/SAM/HTL/Ag, where HTL represents a hole-transporting layer. It is shown that depending on the HTL used and thus the HOMO level involved, the maximum current injection into the device occurred with differently modified Ag. Top-emitting organic light-emitting diodes fabricated with differently modified silver electrodes showed that the maximum current and maximum luminance efficiency occur at anodes of different modifications due to a change in the hole-electron charge balance.