Aerosol Release by Healthy People during Speaking: Possible Contribution to the Transmission of SARS-CoV-2.

Our research aimed to review the potential risk of infection by SARS-CoV-2. We used an excerpt of a data set generated in May 2020 for reviewing the SARS-CoV-2 prevention concept of orchestras, singers and actors. People were sampled for droplet release for one-hour activities using a Grimm spectrometer covering a spectrum of 1 to 32 µm diameter. We estimated the number of "quanta" in the exhaled liquid from viral concentrations of 106 to 1011/mL, based on the Human Infective Dose 50 of 218 viral particles. We employed the Wells-Riley equation to estimate the risk of infection in typical meeting rooms for a one-hour meeting of 2, 4 and 6 people observing a 2 m distance. The four participating adults released a mean of 1.28 nLm3 while breathing, 1.68 nL/m3 while speaking normally, and two adults released a mean of 4.44 nL/m3 while talking with a raised voice. The combination of 50% breathing, 45% talking normally and 5% speaking with a raised voice increased the risk of infection above 5% for a one-hour meeting of two people. The result is based on 6 quanta released, corresponding to an initial virus concentration of 1000/nL (109/mL) in the fluid of the upper respiratory tract. Our data confirm the importance of using facemasks in combination with other measures to prevent transmission of SARS-CoV-2 at the workplace.

Classification of dermal sensitizers in pharmaceutical manufacturing.

Workers in development and manufacturing of pharmaceuticals are at risk for occupational contact dermatitis (OCD) of irritative (ICD) or allergic (ACD) origin, due to contacts with reactive intermediates (IM) and drug substances (DS). We examined, if alternative methods could replace presently used animal tests for identification of ACD in pharmaceutical development and manufacturing, without apparent loss of worker health, in line with regulations. The status of alternative methods for regulatory toxicology for consumer products has recently been reviewed by the Organisation for Economic Co-operation and Development (OECD) and the European Commission's Joint Research Center (JRC) for the European Chemicals Agency (ECHA). They concluded that prediction of skin sensitization potential, extent and quality by in vitro methods, for regulatory assessments, will depend on the regulatory purpose and level of confidence required. Some alternative methods are currently in validation. Current Globally Harmonized System (GHS) regulations on classification, labeling and packaging of substances and mixtures depend on human and animal data, whereas alternative methods may provide supportive evidence. Since the levels of workplace skin exposure to DS and IM in manufacturing of pharmaceuticals are usually not known, it is not possible to conduct quantitative risk assessments based on threshold calculations for contact sensitizers.

Predictors of marked weight gain in a population of health care and industrial workers following smoking cessation.

BACKGROUND: Concerns about postcessational weight gain might hamper rather than encourage smokers to quit smoking. METHODS: We conducted a comprehensive multi-institutional smoking cessation program for health care and industrial workers (n = 654) employed at University Hospital Basel (Switzerland) and two local health industry companies (Novartis International AG, F. Hoffmann-La Roche AG). The program contained counselling with an option of pharmacological support. Changes in body weight were observed during 24 months of follow-up. Factors associated with longitudinal weight gain (> 5 % of baseline weight) were identified by cox-regression analysis. RESULTS: In 51 % of permanent quitters no significant changes of mean body weight were observed after 12 (0.52 kg, SD ± 2.87 kg) and 24 months (0.40 kg, SD ± 2.99 kg). Marked weight gain following smoking cessation was characterized by a wide margin of changes. In more than a half of former smokers (58 %) weight increases were moderate (< 5 kg), whereas excessive increases (> 10 kg) were seen in only 10 % of quitters. Lower baseline BMI (HR 0.60, 95 % CI 0.40- 0.80, p = 0.03), daily consumption of less than ten cigarettes (HR 0.53, 95 % CI 0.27- 0.63, p = 0.04) and ischemic cardiopathy (HR 0.21, 95 % CI 0.07-0.62; p < 0.01) were associated with a lower risk for weight gain. Employees with lower educational levels (HR 2.60, 95 % CI 1.60-5.50, p < 0.01), diabetes mellitus (HR 3.05, 95 % CI 2.20-8.06, p = 0.02) and those smoking to reduce boredom in life (HR 1.68, 95 % CI 1.21-2.33, p < 0.01) were at highest risk. CONCLUSION: Marked postcessational weight gain occurs less often than expected, but remains difficult to be predicted. Our findings might be helpful to alleviate weight concerns in the average smoker willing to quit.

Cancer risk of immunosuppressants in manufacturing.

During the chemical and pharmaceutical production of active pharmaceutical substances which are intended for immunosuppressive therapy, the employees may be exposed to these substances via inhalation. Immunosuppressants are linked to development of certain types of cancers e.g., lymphoma or skin cancer in transplant patients. The development of these cancers in patients is linked to the level of immunosuppression needed for transplantation in order to avoid organ rejection. Below these levels, with the immune system functioning uninhibited, cancer is unlikely to develop. An internal workshop was conducted to compare several pharmaceutical substances with the intrinsic property to cause immunosuppression, with the attempt to define the risk of healthy employees to develop cancer due to exposure to immunosuppressive substance at work and to determine the appropriate hazard classification for regulatory purposes. Data are discussed with emphasis on cyclosporine to reason the dose-response relationship and the safe level for occupational exposure. Our review indicates that if the exposure to cyclosporine at the workplace is below the threshold necessary to induce immunosuppression, the risk to develop cancer is negligible. Non-mutagenic immunosuppressants do not contribute to malignancies in occupational setting if their air concentrations do not exceed the immunosuppressive threshold limited with occupational exposure limits (OELs), which is for cyclosporine 17.5µg/m(3).

Predictors of success for smoking cessation at the workplace: a longitudinal study.

BACKGROUND: The effectiveness of worksite interventions to reduce smoking is debatable. OBJECTIVES: A comprehensive smoking cessation intervention was implemented in a community of more than 17,000 employees at three different health care companies. The primary endpoint was abstinence at 24 months (self-reported and confirmed by exhaled carbon monoxide ≤ 6 parts per million). Predictors of long-term abstinence were analysed by multivariable regression analysis. METHODS: The study was designed as an investigator-initiated and investigator-driven, open, multicentre, cohort study; 887 smokers were enrolled in the programme. The intervention included intensive individual counselling as well as nicotine replacement and/or bupropion according to individual preferences. Re-interventions for relapse were offered during the 24-month follow-up. RESULTS: The abstinence rate was 37% at 24 months and did not differ among the various medication groups (p > 0.05 for all). Predictors of successful cessation were higher age (odds ratio, OR 1.47, 95% confidence interval, CI 1.08-2.00, p < 0.01), breathlessness on exertion (OR 2.26, 95% CI 1.1-4.9, p = 0.03), and a higher educational level (OR 1.81, 95% CI 1.06-3.09, p = 0.03). Higher Fagerström (OR 0.76, 95% CI 0.59-0.97, p < 0.01) and craving scores (OR 0.75, 95% CI 0.63-0.89, p < 0.01), chronic sputum production (OR 0.52, 95% CI 0.31-0.87, p = 0.01) and use of antidepressants (OR 0.54, 95% CI 0.32-0.91, p = 0.02) were associated with ongoing smoking. CONCLUSION: A comprehensive smoking cessation intervention at the workplace achieves high, stable, long-term abstinence rates. Elderly, well-educated employees with breathlessness on exertion have higher odds of quitting smoking. In contrast, those with high physical dependency and more intense craving, and those reporting use of antidepressant medication or sputum production have poorer chances to quit.

Estimating the direct-to-reverberant energy ratio from the coherence between coincident pressure and particle velocity.

An analytical expression for the relationship between the direct-to-reverberant energy ratio (DRR) and the coherence estimation function between coincident pressure and particle velocity component is derived. The analytical solution is first validated with simulated room impulse responses and then used to estimate the DRR in five octave bands for several receiver positions measured in a total of 11 rooms of vastly different sizes and acoustic characteristics. The accuracy is evaluated by comparison with the DRR estimated directly from the room impulse response. The difference is typically 5 dB. For two rooms, the variation of the DRR estimate with source-to-receiver position is also shown. The method is blind in the sense that it is virtually independent of the signal generated by a single sound source.

Reliability of estimating the room volume from a single room impulse response.

The methods investigated for the room volume estimation are based on geometrical acoustics, eigenmode, and diffuse field models and no data other than the room impulse response are available. The measurements include several receiver positions in a total of 12 rooms of vastly different sizes and acoustic characteristics. The limitations in identifying the pivotal specular reflections of the geometrical acoustics model in measured room impulse responses are examined both theoretically and experimentally. The eigenmode method uses the theoretical expression for the Schroeder frequency and the difficulty of accurately estimating this frequency from the varying statistics of the room transfer function is highlighted. Reliable results are only obtained with the diffuse field model and a part of the observed variance in the experimental results is explained by theoretical expressions for the standard deviation of the reverberant sound pressure and the reverberation time. The limitations due to source and receiver directivity are discussed and a simple volume estimation method based on an approximate relationship with the reverberation time is also presented.

Spatial correlation and coherence in reverberant acoustic fields: Extension to microphones with arbitrary first-order directivity.

Spatial correlation and coherence functions in reverberant sound fields are relevant to the acoustics of enclosed spaces and related areas. Theoretical expressions for the spatial correlation and coherence functions between signals representing the pressure and/or the components of the particle velocity vector in a reverberant sound field are established in the literature and most of these have also been corroborated with measurements [F. Jacobsen, J. Acoust. Soc. Am. 108, 204-210 (2000)]. In the present paper, these expressions are generalized to microphones of first-order directivity, whereby the directivity can be expressed in terms of pressure and pressure gradient. It is shown that the resulting spatial correlation and coherence functions can be expressed in terms of the established spatial correlation and coherence functions. The derived theoretical expression for the spatial coherence function is validated with a modeled diffuse sound field. Further, it is compared with the experimental coherence obtained from the reverberant tails of room impulse responses measured with two common surround sound microphone setups in a concert and a lecture hall.