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We measured the trigonometric parallax of the H2O maser source associated with the L 1482 molecular filament hosting the most massive young star, LkHα 101, in the California molecular cloud. The measured parallax is 1.879 ± 0.096 mas, corresponding to the distance of 532 ± 28 pc. This parallax is consistent with that of the nearby star cluster LkHα 101, which was recently measured with Gaia DR2. We found that the L 1482 molecular filament and the LkHα 101 cluster are located at the same distance within 3 ± 30 pc. We observed the southern parts of L 1482 molecular clouds including the H2O maser source, which is adjacent to LkHα 101, using the Nobeyama 45 m telescope in the J = 1–0 transitions of both 12CO and 13CO. The peak intensity of the 12CO line revealed the high excitation temperature region (60–70 K) due to heating by UV radiation from LkHα 101. We derived the column density of these molecular clouds assuming local thermodynamic equilibrium (LTE) from the 13CO emission. Using Dendrogam, we searched for small-scale, dense structures (cores) and identified 337 cores in the 13CO data. Gravitationally bound cores with a virial mass to LTE mass ratio ≤1.5 and young stars are concentrated in the high excitation temperature region. The column density in the warm region is five to six times larger than that of the surrounding colder molecular region. This suggests that the warm region has been compressed by a high-pressure wave and successive radiation-driven star formation is in progress in this warm region. In the cold molecular cloud to the north of the warm region, the cores are likely gravitationally unbound, which may be the reason why star formation is not active there.

Multi-drug resistant tuberculosis (MDR-TB) has become a serious concern for proper treatment of patients. As a phenotypic method, dielectrophoresis can be useful but is yet to be attempted to evaluate Mycobacterium tuberculosis complex cells. This paper investigates the dielectrophoretic behavior of Mycobacterium bovis (Bacillus Calmette-Guerin, BCG) cells that are treated with heat or antibiotics rifampin (RIF) or isoniazid (INH). The experimental parameters are designed on the basis of our sensitivity analysis. The medium conductivity (σ m) and the frequency (f) for a crossover frequency (f xo1) test are decided to detect the change of σ m-f xo1 in conjunction with the drug mechanism. Statistical modeling is conducted to estimate the distributions of viable and nonviable cells from the discrete measurement of f xo1. Finally, the parameters of the electrophysiology of BCG cells, C envelope and σ cyto, are extracted through a sampling algorithm. This is the first evaluation of the dielectrophoresis (DEP) approach as a means to assess the effects of antimicrobial drugs on M. tuberculosis complex cells.

An occupationally safe (biosafe) sputum liquefaction protocol was developed for use with a semi-automated antibody-based microtip immunofluorescence sensor. The protocol effectively liquefied sputum and inactivated microorganisms including Mycobacterium tuberculosis, while preserving the antibody-binding activity of Mycobacterium cell surface antigens. Sputum was treated with a synergistic chemical-thermal protocol that included moderate concentrations of NaOH and detergent at 60°C for 5 to 10 min. Samples spiked with M. tuberculosis complex cells showed approximately 10(6)-fold inactivation of the pathogen after treatment. Antibody binding was retained post-treatment, as determined by analysis with a microtip immunosensor. The sensor correctly distinguished between Mycobacterium species and other cell types naturally present in biosafe-treated sputum, with a detection limit of 100 CFU/mL for M. tuberculosis, in a 30-minute sample-to-result process. The microtip device was also semi-automated and shown to be compatible with low-cost, LED-powered fluorescence microscopy. The device and biosafe sputum liquefaction method opens the door to rapid detection of tuberculosis in settings with limited laboratory infrastructure.

Tuberculosis (TB) has been a major public health problem, which can be better controlled by using accurate and rapid diagnosis in low-resource settings. A simple, portable, and sensitive detection method is required for point-of-care (POC) settings. This paper studies an amperometric biosensor using a microtip immunoassay for a rapid and low cost detection of Mycobacterium Tuberculosis (MTB) in sputum. MTB in sputum is specifically captured on the functionalized microtip surface and detected by electric current. According to the numerical study, the current signal on microtip surface is linearly changed with increasing immersion depth. Using a reference microtip, the immersion depth is compensated for a sensing microtip. On the microtip surface, target bacteria are concentrated and organized by a coffee ring effect, which amplifies the electric current. To enhance the signal-to-noise ratio, both the sample processing- and rinsing steps are presented with use of deionized water as a medium for the amperometric measurement. When applied to cultured MTB cells spiked into human sputum, the detection limit was 100 CFU/mL, comparable to a more labor-intensive fluorescence detection method reported previously.