Mats E. Nilsson

Stress Recovery during Exposure to Nature Sound and Environmental Noise

Research suggests that visual impressions of natural compared with urban environments facilitate recovery after psychological stress. To test whether auditory stimulation has similar effects, 40 subjects were exposed to sounds from nature or noisy environments after a stressful mental arithmetic task. Skin conductance level (SCL) was used to index sympathetic activation, and high frequency heart rate variability (HF HRV) was used to index parasympathetic activation. Although HF HRV showed no effects, SCL recovery tended to be faster during natural sound than noisy environments. These results suggest that nature sounds facilitate recovery from sympathetic activation after a psychological stressor.

Long-Term Exposure to Road Traffic Noise and Myocardial Infarction

Background: An association has been reported between long-term exposure to road traffic noise and the risk of myocardial infarction (MI), but the evidence is limited and inconclusive. No previous study has simultaneously analyzed the role of exposure to noise and air pollution from road traffic in the risk of MI. Methods: A population-based case-control study on MI was conducted 1992–1994 in Stockholm County. Participants answered a questionnaire and underwent a physical examination. Residential exposure to noise and air pollution from road traffic between 1970 and 1992–1994 was assessed for 3666 participants (1571 cases of MI and 2095 controls), based on residential history combined with information on traffic intensity and distance to nearby roads. Information was also obtained on factors potentially affecting the relationship between noise exposure and MI, such as noise annoyance. Results: The correlation between long-term individual exposure to noise and air pollution from traffic was high (r = 0.6). The adjusted odds ratio for MI associated with long-term road traffic noise exposure of 50 dBA or higher was 1.12 (95% confidence interval = 0.95–1.33). In a subsample, defined by excluding persons with hearing loss or exposure to noise from other sources, the corresponding odds ratio was 1.38 (1.11–1.71), with a positive exposure–response trend. No strong effect modification was apparent by sex or cardiovascular risk factors, including air pollution from road traffic. Conclusions: The results lend some support to the hypothesis that long-term exposure to road traffic noise increases the risk for MI.

A model for the perception of environmental sound based on notice-events

An approach is proposed to shed light on the mechanisms underlying human perception of environmental sound that intrudes in everyday living. Most research on exposure-effect relationships aims at relating overall effects to overall exposure indicators in an epidemiological fashion, without including available knowledge on the possible underlying mechanisms. Here, it is proposed to start from available knowledge on audition and perception to construct a computational framework for the effect of environmental sound on individuals. Obviously, at the individual level additional mechanisms (inter-sensory, attentional, cognitive, emotional) play a role in the perception of environmental sound. As a first step, current knowledge is made explicit by building a model mimicking some aspects of human auditory perception. This model is grounded in the hypothesis that long-term perception of environmental sound is determined primarily by short notice-events. The applicability of the notice-event model is illustrated by simulating a synthetic population exposed to typical Flemish environmental noise. From these simulation results, it is demonstrated that the notice-event model is able to mimic the differences between the annoyance caused by road traffic noise exposure and railway traffic noise exposure that are also observed empirically in other studies and thus could provide an explanation for these differences.

Auditory masking of wanted and unwanted sounds in a city park

Auditory masking of unwanted sounds by wanted sounds has been suggested as a tool for outdoor acoustic design. Anecdotal evidence exists for successful applications, for instance the use of fountai ...

The Potential of Natural Sounds to Mask Wind Turbine Noise

Wind turbine (WT) noise may cause annoyance, especially in relatively quiet areas with low ambient levels. As a compliment to conventional noise control at the source, addition of wanted sounds may ...

Novel Readout Method for Molecular Diagnostic Assays Based on Optical Measurements of Magnetic Nanobead Dynamics

We demonstrate detection of DNA coils formed from a Vibrio cholerae DNA target at picomolar concentrations using a novel optomagnetic approach exploiting the dynamic behavior and optical anisotropy of magnetic nanobead (MNB) assemblies. We establish that the complex second harmonic optical transmission spectra of MNB suspensions measured upon application of a weak uniaxial AC magnetic field correlate well with the rotation dynamics of the individual MNBs. Adding a target analyte to the solution leads to the formation of permanent MNB clusters, namely, to the suppression of the dynamic MNB behavior. We prove that the optical transmission spectra are highly sensitive to the formation of permanent MNB clusters and, thereby to the target analyte concentration. As a specific clinically relevant diagnostic case, we detect DNA coils formed via padlock probe recognition and isothermal rolling circle amplification and benchmark against a commercial equipment. The results demonstrate the fast optomagnetic readout of rolling circle products from bacterial DNA utilizing the dynamic properties of MNBs in a miniaturized and low-cost platform requiring only a transparent window in the chip.

A General Method for Rapid Determination of Antibiotic Susceptibility and Species in Bacterial Infections

ABSTRACT To ensure correct antibiotic treatment and reduce the unnecessary use of antibiotics, there is an urgent need for new rapid methods for species identification and determination of antibiotic susceptibility in infectious pathogenic bacteria. We have developed a general method for the rapid identification of the bacterial species causing an infection and the determination of their antibiotic susceptibility profiles. An initial short cultivation step in the absence and presence of different antibiotics was combined with sensitive species-specific padlock probe detection of the bacterial target DNA to allow a determination of growth (i.e., resistance) and no growth (i.e., susceptibility). A proof-of-concept was established for urinary tract infections in which we applied the method to determine the antibiotic susceptibility profiles of Escherichia coli for two drugs with 100% accuracy in 3.5 h. The short assay time from sample to readout enables fast appropriate treatment with effective drugs and minimizes the need to prescribe broad-spectrum antibiotics due to unknown resistance profiles of the treated infection.

Children's annoyance reactions to aircraft and road traffic noise

Since annoyance reactions of children to environmental noise have rarely been investigated, no source specific exposure-response relations are available. The aim of this paper is to investigate childrens reactions to aircraft and road traffic noise and to derive exposure-response relations. To this end, childrens annoyance reactions to aircraft and road traffic noise in both the home and the school setting were investigated using the data gathered in a cross-sectional multicenter study, carried out among 2844 children (age 9-11 years) attending 89 primary schools around three European airports. An exposure-response relation was demonstrated between exposure to aircraft noise at school (L(Aeq,7-23 h)) and severe annoyance in children: after adjustment for confounders, the percentage severely annoyed children was predicted to increase from about 5.1% at 50 dB to about 12.1% at 60 dB. The findings were consistent across the three samples. Aircraft noise at home (L(Aeq,7-23 h)) demonstrated a similar relation with severe annoyance. Children attending schools with higher road traffic noise (L(Aeq,7-23 h)) were more annoyed. Although children were less annoyed at levels above 55 dB, the shapes of the exposure-response relations found among children were comparable to those found in their parents.

Human echolocation: pitch versus loudness information.

Blind persons emit sounds to detect objects by echolocation. Both perceived pitch and perceived loudness of the emitted sound change as they fuse with the reflections from nearby objects. Blind persons generally are better than sighted at echolocation, but it is unclear whether this superiority is related to detection of pitch, loudness, or both. We measured the ability of twelve blind and twenty-five sighted listeners to determine which of two sounds, 500 ms noise bursts, that had been recorded in the presence of a reflecting object in a room with reflecting walls using an artificial head. The sound pairs were original recordings differing in both pitch and loudness, or manipulated recordings with either the pitch or the loudness information removed. Observers responded using a 2AFC method with verbal feedback. For both blind and sighted listeners the performance declined more with the pitch information removed than with the loudness information removed. In addition, the blind performed clearly better than the sighted as long as the pitch information was present, but not when it was removed. Taken together, these results show that the ability to detect pitch is a main factor underlying high performance in human echolocation.

Scalable DNA-Based Magnetic Nanoparticle Agglutination Assay for Bacterial Detection in Patient Samples

We demonstrate a nanoparticle-based assay for the detection of bacteria causing urinary tract infections in patient samples with a total assay time of 4 h. This time is significantly shorter than the current gold standard, plate culture, which can take several days depending on the pathogen. The assay is based on padlock probe recognition followed by two cycles of rolling circle amplification (RCA) to form DNA coils corresponding to the target bacterial DNA. The readout of the RCA products is based on optomagnetic measurements of the specific agglutination of DNA-bound magnetic nanoparticles (MNPs) using low-cost optoelectronic components from Blu-ray drives. We implement a detection approach, which relies on the monomerization of the RCA products, the use of the monomers to link and agglutinate two populations of MNPs functionalized with universal nontarget specific detection probes and on the introduction of a magnetic incubation scheme. This enables multiplex detection of Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa at clinically relevant concentrations, demonstrating a factor of 30 improvement in sensitivity compared to previous MNP-based detection schemes. Thanks to the universal probes, the same set of functionalized MNPs can be used to read out products from a multitude of RCA targets, making the approach truly scalable for parallel detection of multiple bacteria in a future integrated point of care molecular diagnostics system.