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Atmospheric new-particle formation (NPF) affects climate by contributing to a large fraction of the cloud condensation nuclei (CCN). Highly oxygenated organic molecules (HOMs) drive the early particle growth and therefore substantially influence the survival of newly formed particles to CCN. Nitrogen oxide (NOx) is known to suppress the NPF driven by HOMs, but the underlying mechanism remains largely unclear. Here, we examine the response of particle growth to the changes of HOM formation caused by NOx. We show that NOx suppresses particle growth in general, but the suppression is rather nonuniform and size dependent, which can be quantitatively explained by the shifted HOM volatility after adding NOx. By illustrating how NOx affects the early growth of new particles, a critical step of CCN formation, our results help provide a refined assessment of the potential climatic effects caused by the diverse changes of NOx level in forest regions around the globe.

Iodic acid (HIO 3 ) is known to form aerosol particles in coastal marine regions, but predicted nucleation and growth rates are lacking. Using the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, we find that the nucleation rates of HIO 3 particles are rapid, even exceeding sulfuric acid-ammonia rates under similar conditions. We also find that ion-induced nucleation involves IO 3 - and the sequential addition of HIO 3 and that it proceeds at the kinetic limit below +10°C. In contrast, neutral nucleation involves the repeated sequential addition of iodous acid (HIO 2 ) followed by HIO 3 , showing that HIO 2 plays a key stabilizing role. Freshly formed particles are composed almost entirely of HIO 3 , which drives rapid particle growth at the kinetic limit. Our measurements indicate that iodine oxoacid particle formation can compete with sulfuric acid in pristine regions of the atmosphere., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

A major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NO x ) and sulfur oxides (SO x ) from fossil fuel combustion, as well as ammonia (NH 3 ) from livestock and fertilizers. Here, we show how NO x suppresses particle formation, while HOMs, sulfuric acid, and NH 3 have a synergistic enhancing effect on particle formation. We postulate a novel mechanism, involving HOMs, sulfuric acid, and ammonia, which is able to closely reproduce observations of particle formation and growth in daytime boreal forest and similar environments. The findings elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.

Ambient inhalable particulate matter (PM) is a serious health concern worldwide, but especially so in China where high PM concentrations affect huge populations. Atmospheric processes and emission sources cause spatial and temporal variations in PM concentration and chemical composition, but their influence on the toxicological characteristics of PM are still inadequately understood. In this study, we report an extensive chemical and toxicological characterization of size-segregated urban air inhalable PM collected in August and October 2013 from Nanjing, and assess the effects of atmospheric processes and likely emission sources. A549 human alveolar epithelial cells were exposed to day- and nighttime PM samples (25, 75, 150, 200, 300 μg/ml) followed by analyses of cytotoxicity, genotoxicity, cell cycle, and inflammatory response. PM 10-2.5 and PM 0.2 caused the greatest toxicological responses for different endpoints, illustrating that particles with differing size and chemical composition activate distinct toxicological pathways in A549 cells. PM 10-2.5 displayed the greatest oxidative stress and genotoxic responses; both were higher for the August samples compared with October. In contrast, PM 0.2 and PM 2.5-1.0 samples displayed high cytotoxicity and substantially disrupted cell cycle; August samples were more cytotoxic whereas October samples displayed higher cell cycle disruption. Several components associated with combustion, traffic, and industrial emissions displayed strong correlations with these toxicological responses. The lower responses for PM 1.0-0.2 compared to PM 0.2 and PM 2.5-1.0 indicate diminished toxicological effects likely due to aerosol aging and lower proportion of fresh emission particles rich in highly reactive chemical components in the PM 1.0-0.2 fraction. Different emission sources and atmospheric processes caused variations in the chemical composition and toxicological responses between PM fractions, sampling campaigns, and day and night. The results indicate different toxicological pathways for coarse-mode particles compared to the smaller particle fractions with typically higher content of combustion-derived components. The variable responses inside PM fractions demonstrate that differences in chemical composition influence the induced toxicological responses., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Secondary organic aerosols (SOA) forms a major fraction of organic aerosols in the atmosphere. Knowledge of SOA properties that affect their dynamics in the atmosphere is needed for improving climate models. By combining experimental and modeling techniques, we investigated the factors controlling SOA evaporation under different humidity conditions. Our experiments support the conclusion of particle phase diffusivity limiting the evaporation under dry conditions. Viscosity of particles at dry conditions was estimated to increase several orders of magnitude during evaporation, up to 10 9  Pa s. However, at atmospherically relevant relative humidity and time scales, our results show that diffusion limitations may have a minor effect on evaporation of the studied α-pinene SOA particles. Based on previous studies and our model simulations, we suggest that, in warm environments dominated by biogenic emissions, the major uncertainty in models describing the SOA particle evaporation is related to the volatility of SOA constituents.

We have developed a multielectrode lead technique to improve the signal-to-noise ratio (SNR) of scalp-recorded electroencephalography (EEG) signals generated deep in the brain. The basis of the method lies in optimization of the measurement sensitivity distribution of the multielectrode lead. We claim that two factors improve the SNR in a multielectrode lead: (1) the sensitivity distribution of a multielectrode lead is more specific in measuring signals generated deep in the brain and (2) spatial averaging of noise occurs when several electrodes are applied in the synthesis of a multielectrode lead. We showed theoretically that within a three-layer spherical head model the sensitivity distributions of multielectrode leads are more specific for deep sources than those of traditional bipolar leads. We also estimated with simulations and with preliminary measurements the total improvement in SNR achieved by both the more specific lead field and spatial averaging. Results obtained with simulations and with experimental measurements show an apparent improvement in SNR obtained with multielectrode leads. This encourages for future development of the method.

We present the four key areas of research-preprocessing, the volume conductor, the forward problem, and the inverse problem-that affect the performance of EEG and MEG source imaging. In each key area we identify prominent approaches and methodologies that have open issues warranting further investigation within the community, challenges associated with certain techniques, and algorithms necessitating clarification of their implications. More than providing definitive answers we aim to identify important open issues in the quest of source localization.

In this paper, we introduce a new modelling related parameter called region of interest sensitivity ratio (ROISR), which describes how well the sensitivity of an electroencephalography (EEG) measurement is concentrated within the region of interest (ROI), i.e. how specific the measurement is to the sources in ROI. We demonstrate the use of the concept by analysing the sensitivity distributions of bipolar EEG measurement. We studied the effects of interelectrode distance of a bipolar EEG lead on the ROISR with cortical and non-cortical ROIs. The sensitivity distributions of EEG leads were calculated analytically by applying a three-layer spherical head model. We suggest that the developed parameter has correlation to the signal-to-noise ratio (SNR) of a measurement, and thus we studied the correlation between ROISR and SNR with 254-channel visual evoked potential (VEP) measurements of two testees. Theoretical simulations indicate that source orientation and location have major impact on the specificity and therefore they should be taken into account when the optimal bipolar electrode configuration is selected. The results also imply that the new ROISR method bears a strong correlation to the SNR of measurement and can thus be applied in the future studies to efficiently evaluate and optimize EEG measurement setups.

Prehospital management of myocardial infarction was evaluated in two differently structured Emergency Medical Service (EMS) systems in Southern Finland: a physician directed EMS with on-site physician involvement (physician EMS) and an EMS without operational physician involvement with paramedics only (non-physician EMS). The management of 641 consecutive acute ST-elevation myocardial infarction (STEMI) patients between 1997 and 1999 (263 patients in the physician EMS group and 378 patients in non-physician EMS group) were studied. Patients treated in the physician EMS received all necessary medical care including thrombolytic therapy at the scene whereas patients in the non-physician EMS were transported to hospital for definitive treatment after initial care. There were no differences in the demographics of the patients. The delays from onset of pain to initiation of thrombolysis were shorter in the physician EMS-group (124+/-101 min (25-723) versus 196+/-150 min (12-835), p<0.001). In 2% of the patients in the physician EMS group the pain to therapy-time was unknown compared to 27% in the non-physician EMS group (p<0.001). Fifty-two patients (20%) in the physician EMS received thrombolytic therapy after cardiopulmonary resuscitation compared to two patients in the non-physician EMS (p<0.001). Of the resuscitated patients in the physician directed EMS group 60% were discharged from the hospital, and 44% of these had a good neurological recovery. We conclude that a physician directed EMS is able to reduce the pain to therapy delays significantly in STEMI patients and may offer thrombolytic therapy to a wider patient group compared to an EMS without operational medical involvement.

We studied the long-term outcome and quality of life of elderly patients after prehospital thrombolysis to treat acute ST-elevation myocardial infarction. Data of 218 patients after prehospital thrombolytic therapy given by two physician staffed Helicopter Emergency Medical Service (HEMS) units were collected prospectively. Physical and mental status was evaluated at 4--6 months after discharge, and 1-year mortality was determined. Patients older than 65 years were compared with those younger than 65 years. There were 112 elderly and 106 younger patients. The elderly patients had more previous coronary events and more medications. Pain to therapy times between the two groups were equal (<65 years: 108+/-93 min (range 27--500 min) versus >65 years: 108+/-70 min (20-357 min)). After 4--6 months, the Barthel Daily Living Index or the Beck Depression Inventory (BDI) (depression, if BDI >/=10) showed no differences between the two groups (<65 years: 99+/-5 (range 65--100) versus >65 years: 98+/-12 (10--100); BDI>/=10, 18% versus 9%). One-year survival was lower among the elderly (79% versus 93%; p=0.001). No differences in the frequency of arrhythmias, haemodynamic problems during thrombolysis or complications such as intracranial haemorrhage after thrombolysis were detected. We concluded that elderly patients treated with prehospital thrombolysis for acute ST-elevation myocardial infarction recover mentally and physically as well as younger patients.

Prehospital thrombolysis for acute ST-elevation myocardial infarction (STEMI) has been shown to improve recovery from myocardial function. We describe prehospital thrombolytic treatment in two patients suffering from STEMI complicated by ventricular fibrillation (VF) on a passenger ship. The importance of a functioning Emergency Medical Service (EMS) system providing guidance for paramedical personnel is discussed briefly. Both our patients survived and returned back to normal life. It is concluded that EMS physician guided prehospital thrombolytic treatment may offer an important therapeutic option for nurses or paramedics in locations out of reach of ordinary EMS services.

The occurrence of arrhythmias and haemodynamic changes was studied prospectively in 226 consecutive patients who received prehospital thrombolysis for acute ST-elevation myocardial infarction (STEMI) in two Helicopter Emergency Medical Service (HEMS) systems in Southern Finland. Of the 226 patients, 129 were classified as receiving early (pain to treatment-time <90 min) and 97 as late (pain to treatment-time >90 min) treatment. Data on all arrhythmias and haemodynamic disturbances during the prehospital phase were collected. Arrhythmias occurred in 39% of all patients (40% in the early and 38% in the late group). A third of the patients received treatment for their arrhythmia (38% in the early group and 24% in the late group, P = NS). The most common arrhythmia was ventricular extrasystoles, which did not require any treatment in the majority of patients. On arrival of the EMS crew, 14% of all patients were hypotensive (14% in the early and 13% in the late group). After thrombolytic treatment, 7% of all patients became hypotensive (7% of the patients in both groups). The most common treatment for hypotension was fluid administration. Of the 15 patients who received thrombolysis after cardiopulmonary resuscitation (CPR), four patients suffered from arrhythmias and six patients developed hypotension after initiation of thrombolytic treatment. Although arrhythmias and haemodynamic changes were frequent in the prehospital setting after initiation of thrombolytic therapy, severe adverse events were rare. Those requiring therapeutic measures responded well to treatment. The occurrence of events was not related to the timing of thrombolysis in relation to the duration of pain.

Objective: To compare the speed and reliability of electrocardiogram (ECG) transmissions from the prehospital setting to a conventional table facsimile device and to an advanced mobile phone in a Helicopter Emergency Medical Service System (HEMS)., Methods: Eighteen authentic ECGs stored in the memory module of a monitor defibrillator were used. The ECGs were (1) sent directly from the monitor defibrillator to a table fax and an advanced mobile phone at the HEMS base; (2) printed out and sent from a mobile fax connected to an ordinary mobile phone to the table fax and the advanced mobile phone at the HEMS base; (3) printed out and sent from an ordinary table fax as well as from a table fax connected to a satellite phone system to the receiving devices at the HEMS base., Results: When the ECGs were sent from the table fax via satellite, the transmission times were longer to the advanced mobile phone than to the table fax at the HEMS base (1 min 54 s+/-0 min 21 s vs. 1 min 37 s+/-0 min 20 s, (mean+/-SD), (P<0.01). Regarding transmission from the other fax devices, there were no differences in transmission times between the two receiving devices. The fastest way to transmit ECGs to the advanced mobile phone was to send it from conventional table fax (1 min 22 s+/-0 min 18 s) and the longest transmission times were with mobile fax connected to mobile phone (5 min 23 s+/-3 min 5 s). In all ECGs transmitted except one the cardiac rhythm and ST-changes could be recognised., Conclusion: An advanced mobile phone is as fast and reliable as a conventional table fax in receiving ECGs. A mobile phone with advanced features is a practical tool for HEMS physicians who need to evaluate ECGs in the prehospital setting.

The degradation of dissolved and colloidal substances from thermomechanical pulp (TMP) by bacteria isolated from a paper mill was studied in a laboratory slide culture system. Burkholderia cepacia strains hydrolysed triglycerides to free fatty acids, and the liberated unsaturated fatty acids were then degraded to some extent. Saturated fatty acids were not notably degraded. However, the branched anteiso-heptadecanoic fatty acid was degraded almost like the unsaturated fatty acids. About 30% of the steryl esters were degraded during 11 days, increasing the concentrations of free sterols. Approximately 25% of the dehydroabietic, and 45% of the abietic and isopimaric resin acids were degraded during 11 days. The degree of unsaturation seemed to be of greater importance for the degradation of fatty acids than the molar mass. No degradation of dissolved hemicelluloses could be observed with any of the nine bacterial strains studied. Burkholderia cepacia strains and one Bacillus coagulans strain degraded monomeric fructose and glucose in winter TMP water, but in summer TMP water, with much lower sugar concentrations, also other Bacillus strains degraded monomeric sugars.

The bacteria of food packaging paper and board were studied. Most of the aerobic strains were spore-formers; members of the genus Bacillus with B. cereus group (B. cereus, B. mycoides, B. thuringiensis), B. polymyxa group (B. polymyxa, B. circulans, B. macerans, B. pabuli), B. brevis and B. licheniformis predominated. The main source of spore-forming bacteria in paper and board was the broke (rejected paper or board, which is repulped and recycled into the process). Gram-negative bacteria were rare in paper and board in spite of their abundance in the stock. A strain of B. pumilus forming clumping, hairy spores may be of significance in aseptic packaging.

A total of 130 Bacillus strains were isolated from dairy products, the dairy environment and from packaging boards and board-producing machines. Ninety-eight of these were members of the B. cereus group (B. cereus, B. mycoides and B. thuringiensis) as determined by whole cell fatty acid composition. Fatty acid composition did not differentiate between the three species. Of the 98 strains, which were indistinguishable by biochemical tests, 87 could be assigned into 21 different phage types (11 strains remained untypable) when tested with 12 B. cereus, B. mycoides and B. thuringiensis phages. The distribution of phage types between strains from different sources showed that the source of contamination of the dairy products was of milk origin and not from the packaging materials. Most strains isolated from the dairy products were able to grow below 10 degrees C, whereas strains from the dairy environment and from board mills had higher minimum growth temperatures.