Use of an accelerometer and a microphone as gas detectors in the online quantitative detection of hydrogen released from ammonia borane by gas chromatography.

The use of an accelerometer as a gas detector in gas chromatography (GC) is described for the first time. A milli-whistle was connected to the outlet of the GC capillary. When the eluted and GC carrier gases pass through the capillary and milli-whistle, a sound is produced. After a fast Fourier transform (FFT), the sound wave generated from the milli-whistle is picked up by a microphone and the resulting vibration of the milli-whistle body can be recorded by an accelerometer. The release of hydrogen gas, as the result of thermal energy, from ammonia borane (NH3BH3), which has been suggested as a storage medium for hydrogen, was selected as the model sample. The findings show that the frequencies generated, either by sound or by the vibration from the whistle body, were identical. The concentration levels of the released hydrogen gas can be determined online, based on the frequency changes. Ammonia borane was placed in a brass reservoir, heated continually, and the released hydrogen gas was directly injected into the GC inlet at 0.5 min intervals, using a home-built electromagnetic pulse injector. The concentration of hydrogen for each injection can be calculated immediately. When the ammonia borane was encapsulated within a polycarbonate (PC) microtube array membrane, the temperature required for the release of hydrogen can be decreased, which would make such a material more convenient for use. The findings indicate that 1.0 mg of ammonia borane can produce hydrogen in the range of 1.0-1.25 mL, in the temperature range of 85-115 °C.

Epidemiological investigation of the first locally acquired case of COVID-19 identified by influenza surveillance-Taiwan, February 2020.

BACKGROUND: COVID-19 and influenza have similar clinical presentations that can range from mild to severe disease. The World Health Organization recommends that countries use existing influenza surveillance to monitor COVID-19 transmission in communities. We aim to describe the surveillance and investigation of COVID-19 at the early stage of the pandemic in Taiwan. METHODS: In February 2020, the Taiwan Centers for Disease Control enhanced COVID-19 surveillance through its existing influenza surveillance. We retrospectively tested patients for SARS-CoV-2 who had symptoms of severe complicated influenza but were negative in influenza testing. We conducted an epidemiological investigation and contact tracing for the index patient and secondary cases to prevent virus transmission. RESULTS: We identified the first COVID-19 patient on February 15 through enhanced COVID-19 surveillance. He had no history of traveling abroad and an unclear history of contact with COVID-19 cases. He presented with influenza-like illness on January 27 and was hospitalized from February 3 to 15. We identified 39 close contacts of the index patient, including 11 family members and 28 healthcare workers. In total, four close family contacts of the index patient tested positive for SARS-CoV-2. An additional 84 close contacts of the four secondary cases were identified and traced; none was diagnosed with COVID-19. CONCLUSIONS: We recommend enhancing COVID-19 surveillance by testing patients with influenza-like illness. To prevent the spread of COVID-19, we recommend using appropriate personal protective equipment when in close contact with patients who present with influenza-like illness or when caring for patients with pneumonia of unknown etiology.