Streak pictures of particles in Case 4 [Pulsation, Re = 12900, <i>Q</i>/<i>AD</i> = 250].

<p>The jet boundary is indicated by the red dashed line. The pictures overlap from <i>t</i> = 0 to (A) the time when the jet is interrupted (<i>t</i> = <i>t</i>_<i>inj</i>), and (B) <i>t</i> = 10<i>t</i>_<i>inj</i>.</p

The instant dispersion pattern of large particles in the interrupted jet (<i>t</i> = 4.5<i>t</i>_<i>inj</i>).

<p>The leading vortex is illustrated by red arrows, and white arrows indicate the particle motion.</p

Summary of data on cough flow penetration distances.

<p><i>t</i>_{<i>inject</i>} is the injection duration in the starting jet stage, <i>t</i>_max is the time when <i>dx</i>/<i>dt</i> < 0.01 m/s and the cough flow is considered to reach the maximum distance.</p

Visualizations of the turbulent round starting and interrupted jets.

<p>Case 1 [pulsation], Case 5 [sinusoidal] and Case 8 [real-cough]. Re_c = 5200 and <i>Q</i>/<i>AD</i> = 100 for all cases. The flow transition from the starting to the interrupted jet stage occurred at <i>U</i>_<i>c</i><i>t</i>/<i>D</i> = 100 when the source supply is terminated.</p

Streamwise penetration distance as a function of time in the complete process of Case 3 [Pulsation, Re = 12900, <i>Q</i>/<i>AD</i> = 150].

<p>Streamwise penetration distance as a function of time in the complete process of Case 3 [Pulsation, Re = 12900, <i>Q</i>/<i>AD</i> = 150].</p

Streamwise penetration distances of the jet tips as a function of time.

<p>(A) starting-jet stage; (B) interrupted-jet stage.</p

Experimental set-up.

<p>(A) Three temporal profiles at the nozzle exit investigated in this study; (B) schematic diagram of the test apparatus; and (C) the two nozzles used in this study (unit: mm). The large nozzle (<i>D</i> = 10 mm) was for the food dye experiments, and the size of the small nozzle (<i>D</i> = 4 mm) was chosen by using the similarity protocol for the particle experiments. <i>x</i>_<i>p</i> is the streamwise penetration distance, and <i>x</i>_<i>0</i> is the virtual origin.</p

Additional file 1: of Exploring surface cleaning strategies in hospital to prevent contact transmission of methicillin-resistant Staphylococcus aureus

Supplementary material. (DOCX 304 kb)

Role of fomites in SARS transmission during the largest hospital outbreak in Hong Kong

<div><p>The epidemic of severe acute respiratory syndrome (SARS) had a significant effect on global society in the early 2000s and the potential of its resurgence exists. Studies on the modes of transmission of SARS are limited though a number of outbreak studies have revealed the possible airborne route. To develop more specific and effective control strategies, we conducted a detailed mechanism-based investigation that explored the role of fomite transmission in the well-known Ward 8A outbreak. We considered three hypothetical transmission routes, i.e., the long-range airborne, fomite and combined routes, in 1,744 scenarios with combinations of some important parameters. A multi-agent model was used to predict the infection risk distributions of the three hypothetical routes. Model selection was carried out for different scenarios to compare the distributions of infection risk with that of the reported attack rates and select the hypotheses with the best fitness. Our results reveal that under the assumed conditions, the SARS coronavirus was most possible to have spread via the combined long-range airborne and fomite routes, and that the fomite route played a non-negligible role in the transmission.</p></div

System architecture of the multi-agent model.

<p>System architecture of the multi-agent model.</p