Pulsed ion deflection to overcome detector saturation in cryogenic ice sampling.

In 2014, we introduced a new experimental approach to study the UV photo-processing of cryogenic ices of astrophysical interest using laser ablation in a combination of ionization and time-of-flight mass spectrometry (ToF-MS). The setup, Mass Analytical Tool to Research Interstellar ICES, allowed us to detect newly formed species at low abundances. However, we found that with the increase in molecular complexity over the years, the detection of larger photoproducts was hindered by the dynamic range of detectors used. Here, we introduce a method to overcome this issue that we expect to be useful for similar applications in other research fields. The concept is based on a precisely controlled high-energy pulser that regulates the voltage across the deflection plates of the ToF-MS instrument to deflect the most abundant species and prevent them from reaching the detector. In this way, the detector sensitivity can be increased from an operating voltage of 2500 V up to 3000 V. The applicability is first illustrated in the simple case of an argon matrix, where 40Ar+ ions are deflected to increase the detection sensitivity for 40Ar2+ at m/z = 20 and 40Ar2+ at m/z = 80 by a factor 30. Similarly, it is shown that substantially larger complex organic molecules, an important species in astrochemical reaction networks, can be measured for UV irradiated methanol ice.

A cryogenic ice setup to simulate carbon atom reactions in interstellar ices.

The design, implementation, and performance of a customized carbon atom beam source for the purpose of investigating solid-state reaction routes in interstellar ices in molecular clouds are discussed. The source is integrated into an existing ultrahigh vacuum setup, SURFace REaction SImulation DEvice (SURFRESIDE2), which extends this double atom (H/D, O, and N) beamline apparatus with a third atom (C) beamline to a unique system that is fully suited to explore complex organic molecule solid-state formation under representative interstellar cloud conditions. The parameter space for this system is discussed, which includes the flux of the carbon atoms hitting the ice sample, their temperature, and the potential impact of temperature on ice reactions. Much effort has been put into constraining the beam size to within the limits of the sample size with the aim of reducing carbon pollution inside the setup. How the C-atom beam performs is quantitatively studied through the example experiment, C + 18O2, and supported by computationally derived activation barriers. The potential for this source to study the solid-state formation of interstellar complex organic molecules through C-atom reactions is discussed.

Volatile organic compounds exposure and cardiovascular effects in hair salons.

BACKGROUND: The relationship between occupational exposures to volatile organic compounds (VOCs) and cardiovascular effects among hairdressing assistants has not been well characterized. AIMS: To investigate whether or not exposure to VOCs was associated with autonomic dysfunction, inflammation and oxidative stress in hairdressing assistants. METHODS: We recruited 62 young healthy assistants working in different hair salons in Taipei. Blood samples were taken from each assistant and heart rate variability (HRV) indices were recorded. VOCs were measured at each assistant's workplace. Mixed-effects models were used to examine the association between blood markers, HRV and VOCs. RESULTS: Exposure to VOCs was associated with increases in serum C-reactive protein (CRP) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as well as decreases in HRV indices. The effect of VOCs exposure on the health parameters measured in this study was greatest during the days on which the subjects were working. CONCLUSIONS: Occupational exposure to VOCs in hair salons can lead to increases in serum CRP and 8-OHdG levels and decreases in HRV indices. Time spent away from the workplace could modify the effects these exposures have on the health parameters described above in these assistants.

The effects of indoor particles on blood pressure and heart rate among young adults in Taipei, Taiwan.

UNLABELLED: This study aims to evaluate whether indoor particles are associated with elevated blood pressure (BP) and heart rate (HR). We recruited 40 young, healthy students from universities in Taipei. We made four home visits in which we took consecutive 48-h measurements of systolic BP, (SBP) diastolic BP (DBP), and HR in each participant. Particulate matter less than 10 microm in diameter (PM(10)), 2.5 microm in diameter (PM(2.5)), and nitrogen dioxide levels were measured at each participant's home. Participants were asked to keep their windows open during the first two visits, and keep their windows shut during the last two visits. We used linear mixed-effects models to associate BP and HR with indoor air pollutants averaged over 1- to 8-h periods prior to physiological measurements. We found indoor PM(10) and PM(2.5) exposures at 1- to 4-h means were associated with an elevation in SBP, DBP, and HR. Effects of indoor PM(10) and PM(2.5) on BP and HR were greatest during the visits with windows open. During windows-closed visits, participants showed no significant change in BP and HR with indoor PM(10) exposure. We concluded that exposures to infiltrated outdoor particles are associated with short-term increases in BP and HR in young and healthy students. Closing windows can reduce indoor PM concentrations and modify the effect of PM(10) on BP and HR in young adults. PRACTICAL IMPLICATIONS: Particulate matter exposure, high blood pressure (BP) and heart rate (HR) have been reported to be associated with increased risk of cardiovascular morbidity and mortality. Exposure to indoor particles is found to be associated with Elevated BP and HR. Closing windows may reduce indoor particles concentrations and modify the effect of particles on BP and HR in young adults in heavily polluted cities.