Film dosimetry for occupant exposure monitoring within Far-UVC installations

Far-UVC radiation between 200 and 230 nm is a promising technology for reducing airborne disease transmission. Previous work with far-UVC lamps has demonstrated the efficacy of far-UVC radiation to inactivate bacteria and viruses while presenting minimal human health hazards. While far-UVC intentionally exposes the occupied space, effectively disinfecting air between occupants, installations must still ensure that occupant eye and skin exposure is within the recommended daily limits. This study examines far-UVC-sensitive films for measuring the dose received by occupants within two real-world far-UVC installations. The film is characterized for accuracy, angular response, wavelength response, and sources of uncertainty in film response, and used to obtain individual exposure doses that account for both the non-uniform irradiance and the unique motion of individuals within the space. Dosimetry results using the films, which account for the time-weighted average exposure of an occupant, ranged from 10% to 49% of the maximum calculated stationary dose based on peak irradiance measurements. Results from this study spotlight the need to incorporate time-weighted average considerations into the design and safety assessment of far-UVC installations to ultimately operate far-UVC technology with its full potential to prevent the spread of potentially fatal infectious diseases.

Assessing the safety of new germicidal far-UVC technologies

The COVID-19 pandemic underscored the crucial importance of enhanced indoor air quality control measures to mitigate the spread of respiratory pathogens. Far-UVC is a type of germicidal ultraviolet technology, with wavelengths between 200 and 235 nm, that has emerged as a highly promising approach for indoor air disinfection. Due to its enhanced safety compared to conventional 254 nm upper-room germicidal systems, far-UVC allows for whole-room direct exposure of occupied spaces, potentially offering greater efficacy, since the total room air is constantly treated. While current evidence supports using far-UVC systems within existing guidelines, understanding the upper safety limit is critical to maximizing its effectiveness, particularly for the acute phase of a pandemic or epidemic when greater protection may be needed. This review article summarizes the substantial present knowledge on far-UVC safety regarding skin and eye exposure and highlights research priorities to discern the maximum exposure levels that avoid adverse effects. We advocate for comprehensive safety studies that explore potential mechanisms of harm, generate action spectra for crucial biological effects and conduct high-dose, long-term exposure trials. Such rigorous scientific investigation will be key to determining safe and effective levels for far-UVC deployment in indoor environments, contributing significantly to future pandemic preparedness and response.

Susceptibility of extremophiles to far-UVC light for bioburden reduction in spacecraft assembly facilities

The prevention and reduction of microbial species entering and leaving Earth's biosphere is a critical aspect of planetary protection research. While various decontamination methods exist and are currently utilized for planetary protection purposes, the use of far-UVC light (200-230 nm) as a means for microbial reduction remains underexplored. Unlike conventional germicidal ultraviolet at 254 nm, which can pose a health risk to humans even with small exposure doses, far-UVC light poses minimal health hazard making it a suitable candidate for implementation in occupied areas of spacecraft assembly facilities. This study investigates the efficacy of far-UVC 222-nm light to inactivate bacteria using microbial species which are relevant to planetary protection either in vegetative cell or spore form. All the tested vegetative cells demonstrated susceptibility to 222-nm exposure, although susceptibility varied among the tested species. Notably, Deinococcus radiodurans, a species highly tolerant to extreme environmental conditions, exhibited the most resistance to far-UVC exposure with a dose of 112 mJ/cm2 required for a 1-log reduction in survival. While spore susceptibility was similar across the species tested, Bacillus pumilus spores were the most resistant of the tested spores when analyzed with a bi-exponential cell killing model (D90 of 6.8 mJ/cm2). Overall, these results demonstrate the efficacy of far-UVC light for reducing microbial bioburden to help ensure the success and safety of future space exploration missions.

Remote or in-clinic? The effect of service delivery mode on hearing aid output: study protocol for a double-blinded, randomised trial in adults with mild to moderate sensorineural hearing loss

BACKGROUND

Teleaudiology can potentially improve access to hearing healthcare services. Remote hearing aid fittings offer a new mode of service delivery that removes barriers of geography and access to an audiologist. Real-ear measurements (REMs) are the gold standard for hearing aid output verification but require in-clinic appointments. This study will investigate whether remote hearing aid fittings can provide clinically equivalent outcomes when compared to current, in-clinic, best practice guidelines.

RESEARCH DESIGN

A repeated measure, double-blinded crossover design will be used. Participants will be randomly allocated to one of two groups to determine order of intervention, balanced for degree of hearing loss.

STUDY SAMPLE

Sixty adults with mild to moderate hearing loss and at least 1 year of experience with hearing aids will be recruited.

DATA COLLECTION AND ANALYSIS

Participants will complete two hearing aid fitting protocols, one using an in-clinic fitting process and the other using a remote (at-home) fitting process. In-clinic fittings will include REMs with adjustments to standard (NAL-NL2) prescription targets. The two fitting protocols will then be randomly assigned to participants in a crossover design, so participants and researchers will be blinded to the order of the two fitting protocols. Participants will then have a 4-week period with follow-up appointments for participant-directed gain adjustment. For each fitting protocol, participants will complete objective measurements of final hearing aid output with REMs, speech-in-noise testing, subjective measurements of hearing aid performance, and quality of life measurements. They will then begin an identical period of living with, adjusting, and objective assessment with the other fitting protocol. Data will be analysed as repeated measures with statistical control for potential confounding variables.

RESULTS

Data will compare the four-frequency average real-ear aided response (4FREAR) for hearing aids programmed in-clinic and hearing aids programmed remotely, after participant-directed gain adjustments. Secondary measures will assess clinically significant differences in estimated speech intelligibility, hearing-related quality of life, hearing aid benefit, sound quality and preference, and speech-in-noise ability.

CONCLUSIONS

This study will inform the development of best practice guidelines for remote hearing aid fittings. If no clinically significant differences are found between in-clinic and remote fit hearing aids, it has the potential to expand teleaudiology initiatives.

TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry, ACTRN12623000028606p . Date of registration: 12 January 2023.

222 nm far-UVC light markedly reduces the level of infectious airborne virus in an occupied room

An emerging intervention for control of airborne-mediated pandemics and epidemics is whole-room far-UVC (200-235 nm). Laboratory studies have shown that 222-nm light inactivates airborne pathogens, potentially without harm to exposed occupants. While encouraging results have been reported in benchtop studies and in room-sized bioaerosol chambers, there is a need for quantitative studies of airborne pathogen reduction in occupied rooms. We quantified far-UVC mediated reduction of aerosolized murine norovirus (MNV) in an occupied mouse-cage cleaning room within an animal-care facility. Benchtop studies suggest that MNV is a conservative surrogate for airborne viruses such as influenza and coronavirus. Using four 222-nm fixtures installed in the ceiling, and staying well within current recommended regulatory limits, far-UVC reduced airborne infectious MNV by 99.8% (95% CI: 98.2-99.9%). Similar to previous room-sized bioaerosol chamber studies on far-UVC efficacy, these results suggest that aerosolized virus susceptibility is significantly higher in room-scale tests than in bench-scale laboratory studies. That said, as opposed to controlled laboratory studies, uncertainties in this study related to airflow patterns, virus residence time, and dose to the collected virus introduce uncertainty into the inactivation estimates. This study is the first to directly demonstrate far-UVC anti-microbial efficacy against airborne pathogens in an occupied indoor location.

Combining immunotherapy with high-dose radiation therapy (HDRT) significantly inhibits tumor growth in a syngeneic mouse model of high-risk neuroblastoma

Purpose

The mortality in patients with MYCN-amplified high-risk neuroblastoma remains greater than 50% despite advances in multimodal therapy. Novel therapies are urgently needed that requires preclinical evaluation in appropriate mice models. Combinatorial treatment with high-dose radiotherapy (HDRT) and immunotherapy has emerged as an effective treatment option in a variety of cancers. Current models of neuroblastoma do not recapitulate the anatomic and immune environment in which multimodal therapies can be effectively tested, and there is a need for an appropriate syngeneic neuroblastoma mice model to study interaction of immunotherapy with host immune cells. Here, we develop a novel syngeneic mouse model of MYCN-amplified neuroblastoma and report the relevance and opportunities of this model to study radiotherapy and immunotherapy.

Materials and methods

A syngeneic allograft tumor model was developed using the murine neuroblastoma cell line 9464D derived a tumor from TH-MYCN transgenic mouse. Tumors were generated by transplanting 1 mm³ portions of 9464D flank tumors into the left kidney of C57Bl/6 mice. We investigated the effect of combining HDRT with anti-PD1 antibody on tumor growth and tumor microenvironment. HDRT (8 Gy x 3) was delivered by the small animal radiation research platform (SARRP). Tumor growth was monitored by ultrasound. To assess the effect on immune cells tumors sections were co-imuunostained for six biomarkers using the Vectra multispectral imaging platform.

Results

Tumor growth was uniform and confined to the kidney in 100% of transplanted tumors. HDRT was largely restricted to the tumor region with minimal scattered out-of-field dose. Combinatorial treatment with HDRT and PD-1 blockade significantly inhibited tumor growth and prolonged mice survival. We observed augmented T-lymphocyte infiltration, especially CD3⁺CD8⁺ lymphocytes, in tumors of mice which received combination treatment.

Conclusion

We have developed a novel syngeneic mouse model of MYCN amplified high-risk neuroblastoma. We have utilized this model to show that combining immunotherapy with HDRT inhibits tumor growth and prolongs mice survival.

Resources and Attitudes Influence Acculturation of Deaf Children with Cochlear Implants

Early detection of hearing loss leads to early intervention-related decisions. Most children with cochlear implants (CIs) are born to hearing parents. Prior evidence suggests that this increased access to oral communication and the "hearing" world means oral communication is prioritized by hearing parents. Language plays a key role within culture and these communication decisions are likely to be associated with children's level of d/Deaf acculturation. This study was based on qualitative interviews. Thirty-two people associated with 14 children were interviewed; these were parents of children with CIs, four children over age 11 years, and teachers of 13 of the children. The study aimed to investigate parental communication decisions on child/family d/Deaf acculturation and the role of access to resources on children's d/Deaf acculturation development. Findings indicate two profiles of family acculturation-oral and bicultural and point to a possible relationship between access to resources and parents' decision-making process.

The abundance of the potential pathogen Staphylococcus hominis in the air microbiome in a dental clinic and its susceptibility to far‐UVC light

The dental clinic air microbiome incorporates microbes from the oral cavity and upper respiratory tract (URT). This study aimed to establish a reliable methodology for air sampling in a dental clinic setting and quantify the abundance of culturable mesophilic aerobic bacteria present in these samples using regression modeling. Staphylococcus hominis, a potentially pathogenic bacterium typically found in the human oropharynx and URT, was consistently isolated. S. hominis was the most abundant species of aerobic bacteria (22%–24%) and comprised 60%–80% of all Staphylococcus spp. The study also assessed the susceptibility of S. hominis to 222 nm‐far‐UVC light in laboratory experiments, which showed an exponential surface inactivation constant of k = 0.475 cm²/mJ. This constant is a critical parameter for future on‐site use of far‐UVC light as a technique for reducing pathogenic bacterial load in dental clinics.

Translation, adaptation, and cross-cultural validation into Brazilian portuguese of the hearing protection assessment questionnaire (HPA)

PURPOSE

The aim of the present study is to translate, adapt, and cross-culturally validate the Brazilian Portuguese version of the questionnaire Hearing Protection Assessment Questionnaire (HPA).

METHODS

The original instrument, developed in English, seeks to assess barriers and supports related to the use of hearing protection devices (HPD), as well as workers' knowledge, habits and attitudes towards occupational noise. The translation, adaptation, and cross-cultural validation of the questionnaire consisted of five steps: Translation of the questionnaire from English to Portuguese; 2) Reverse translation from Portuguese to English; 3) Analysis of the instrument by three experts in the field; 4) Pre-test of the questionnaire with ten workers; 5) Application of the instrument to 509 workers in a meatpacking industry after the pre-employment medical exam.

RESULTS

The results indicate the construction and content validity of the Brazilian Portuguese version for use with a working population and its internal consistency.

CONCLUSION

This study resulted in the translation, cultural adaptation, and validation of the Hearing Protection Assessment Questionnaire (HPA), in order to be used to assess the use of individual hearing protection in the occupational field, called Hearing Protection Assessment Questionnaire (HPA).

Ocular and Facial Far-UVC Doses from Ceiling-Mounted 222 nm Far-UVC Fixtures

Far-UVC radiation, defined in this paper as ultraviolet (UV) radiation with wavelengths from 200 to 235 nm, is a promising tool to help prevent the spread of disease. The unique advantage of far-UVC technology over traditional UV germicidal irradiation lies in the potential for direct application of far-UVC into occupied spaces since antimicrobial doses of far-UVC are significantly below the recommended daily safe exposure limits. This study used a ceiling-mounted far-UVC fixture emitting at 222 nm to directly irradiate an indoor space and then evaluated the doses received upon a manikin. Radiation-sensitive film was affixed to the head, nose, lip and eyes of the manikin, and the 8-h equivalent exposure dose was determined. Variables examined included manikin height (sitting or standing position), manikin offset from directly below the fixture, tilt of the manikin, the addition of glasses, the addition of hair and different anatomical feature sizes. Importantly, at the manikin position with the highest dose to eyes, the average eye dose was only 5.8% of the maximum directly measured dose. These results provide the first experimental analysis of possible exposure doses a human would experience from an indoor far-UVC installation.

No Evidence of Induced Skin Cancer or Other Skin Abnormalities after Long-Term (66 week) Chronic Exposure to 222-nm Far-UVC Radiation

Far-UVC radiation, typically defined as 200-235 nm, has similar or greater anti-microbial efficacy compared with conventional 254-nm germicidal radiation. In addition, biophysical considerations of the interaction of far-UVC with tissue, as well as multiple short-term safety studies in animal models and humans, suggest that far-UVC exposure may be safe for skin and eye tissue. Nevertheless, the potential for skin cancer after chronic long-term exposure to far-UVC has not been studied. Here, we assessed far-UVC induced carcinogenic skin changes and other pathological dermal abnormalities in 96 SKH-1 hairless mice of both sexes that were exposed to average daily dorsal skin doses of 400, 130 or 55 mJ cm^-2 of 222 nm far-UVC radiation for 66 weeks, 5 days per week, 8 h per day, as well as similarly-treated unexposed controls. No evidence for increased skin cancer, abnormal skin growths or incidental skin pathology findings was observed in the far-UVC-exposed mice. In addition, there were no significant changes in morbidity or mortality. The findings from this study support the long-term safety of long-term chronic exposure to far-UVC radiation, and therefore its potential suitability as a practical anti-microbial approach to reduce airborne viral and bacterial loads in occupied indoor settings.

Meaning in Music Is Intentional, but in Soundscape It Is Not-A Naturalistic Approach to the Qualia of Sounds

The sound environment and music intersect in several ways and the same holds true for the soundscape and our internal response to listening to music. Music may be part of a sound environment or take on some aspects of environmental sound, and therefore some of the soundscape response may be experienced alongside the response to the music. At a deeper level, coping with music, spoken language, and the sound environment may all have influenced our evolution, and the cognitive-emotional structures and responses evoked by all three sources of acoustic information may be, to some extent, the same. This paper distinguishes and defines the extent of our understanding about the interplay of external sound and our internal response to it in both musical and real-world environments. It takes a naturalistic approach to music/sound and music-listening/soundscapes to describe in objective terms some mechanisms of sense-making and interactions with the sounds. It starts from a definition of sound as vibrational and transferable energy that impinges on our body and our senses, with a dynamic tension between lower-level coping mechanisms and higher-level affective and cognitive functioning. In this way, we establish both commonalities and differences between musical responses and soundscapes. Future research will allow this understanding to grow and be refined further.

Tracing the international arrivals of SARS-CoV-2 Omicron variants after Aotearoa New Zealand reopened its border

In the second quarter of 2022, there was a global surge of emergent SARS-CoV-2 lineages that had a distinct growth advantage over then-dominant Omicron BA.1 and BA.2 lineages. By generating 10,403 Omicron genomes, we show that Aotearoa New Zealand observed an influx of these immune-evasive variants (BA.2.12.1, BA.4, and BA.5) through the border. This is explained by the return to significant levels of international travel following the border's reopening in March 2022. We estimate one Omicron transmission event from the border to the community for every ~5,000 passenger arrivals at the current levels of travel and restriction. Although most of these introductions did not instigate any detected onward transmission, a small minority triggered large outbreaks. Genomic surveillance at the border provides a lens on the rate at which new variants might gain a foothold and trigger new waves of infection.

Shared cultural ancestry predicts the global diffusion of democracy

Understanding global variation in democratic outcomes is critical to efforts to promote and sustain democracy today. Here, we use data on the democratic status of 221 modern and historical nations stretching back up to 200 years to show that, particularly over the last 50 years, nations with shared linguistic and, more recently, religious ancestry have more similar democratic outcomes. We also find evidence that for most of the last 50 years the democratic trajectory of a nation can be predicted by the democratic status of its linguistic and, less clearly, religious relatives, years and even decades earlier. These results are broadly consistent across three democracy indicators (Polity 5, Vanhanen's Index of Democracy, and Freedom in the World) and are not explained by geographical proximity or current shared language or religion. Our findings suggest that deep cultural ancestry remains an important force shaping the fortunes of modern nations, at least in part because democratic norms, institutions, and the factors that support them are more likely to diffuse between close cultural relatives.

Evaluation of the Dangerous Decibels Brazil Program in Workers Exposed to Noise

Introduction

Noise-induced hearing loss can be avoided by taking preventive measures.

Objective

To assess the effectiveness of the Brazilian version of the Dangerous Decibels® program for noise-exposed workers, using the ecological model as an educational intervention plan.

Method

Non-randomized interventional study with a quantitative, experimental trial design, conducted at a meatpacking company. The participants were divided into two groups—the first one (n = 132, divided into 6 subgroups) received the Dangerous Decibels® Brazil educational intervention (DDBEI) adapted to workers while the second group (n = 138, divided into 5 subgroups) received a conventional educational intervention (CEI). The interventions lasted 50 min. The Hearing Protection Assessment Questionnaire (HPA-5) was administered before and after the interventions. The five dimensions (attitude, behavior, knowledge, supports, and barriers) were compared using the Student’s t-test for paired data (<0.05).

Results

After both the DDBEI and CEI training, workers improved significantly in barriers, supports, knowledge, attitudes, and behavior around noise. By chance, the CEI group scored lower in all measures than the DDBEI group before training, and though both groups improved, the difference was maintained after training.

Conclusion

The Brazilian version of the Dangerous Decibels® program for noise-exposed workers was effective, influencing positively the factors at different levels of the ecological model. Though the DDBEI was no more effective than the CEI, the CEI participants began at much lower levels, so the effectiveness of the DDBEI may have been underestimated.

Genomic epidemiology of Delta SARS-CoV-2 during transition from elimination to suppression in Aotearoa New Zealand

New Zealand’s COVID-19 elimination strategy heavily relied on the use of genomics to inform contact tracing, linking cases to the border and to clusters during community outbreaks. In August 2021, New Zealand entered its second nationwide lockdown after the detection of a single community case with no immediately apparent epidemiological link to the border. This incursion resulted in the largest outbreak seen in New Zealand caused by the Delta Variant of Concern. Here we generated 3806 high quality SARS-CoV-2 genomes from cases reported in New Zealand between 17 August and 1 December 2021, representing 43% of reported cases. We detected wide geographical spread coupled with undetected community transmission, characterised by the apparent extinction and reappearance of genomically linked clusters. We also identified the emergence, and near replacement, of genomes possessing a 10-nucleotide frameshift deletion that caused the likely truncation of accessory protein ORF7a. By early October, New Zealand moved from an elimination strategy to a suppression strategy and the role of genomics changed markedly from being used to track and trace, towards population-level surveillance.

Aotearoa New Zealand pursued a COVID-19 elimination strategy until October 2021 when it moved to a suppression strategy. In this genomic surveillance study, the authors describe spread of the virus during the transition between these strategies, with evidence of substantial undetected community transmission.

Accounting for errors in data improves divergence time estimates in single-cell cancer evolution

Single-cell sequencing provides a new way to explore the evolutionary history of cells. Compared to traditional bulk sequencing, where a population of heterogeneous cells is pooled to form a single observation, single-cell sequencing isolates and amplifies genetic material from individual cells, thereby preserving the information about the origin of the sequences. However, single-cell data is more error-prone than bulk sequencing data due to the limited genomic material available per cell. Here, we present error and mutation models for evolutionary inference of single-cell data within a mature and extensible Bayesian framework, BEAST2. Our framework enables integration with biologically informative models such as relaxed molecular clocks and population dynamic models. Our simulations show that modeling errors increase the accuracy of relative divergence times and substitution parameters. We reconstruct the phylogenetic history of a colorectal cancer patient and a healthy patient from single-cell DNA sequencing data. We find that the estimated times of terminal splitting events are shifted forward in time compared to models which ignore errors. We observed that not accounting for errors can overestimate the phylogenetic diversity in single-cell DNA sequencing data. We estimate that 30-50% of the apparent diversity can be attributed to error. Our work enables a full Bayesian approach capable of accounting for errors in the data within the integrative Bayesian software framework BEAST2.

Far-UVC (222 nm) efficiently inactivates an airborne pathogen in a room-sized chamber

Many infectious diseases, including COVID-19, are transmitted by airborne pathogens. There is a need for effective environmental control measures which, ideally, are not reliant on human behaviour. One potential solution is Krypton Chloride (KrCl) excimer lamps (often referred to as Far-UVC), which can efficiently inactivate pathogens, such as coronaviruses and influenza, in air. Research demonstrates that when KrCl lamps are filtered to remove longer-wavelength ultraviolet emissions they do not induce acute reactions in the skin or eyes, nor delayed effects such as skin cancer. While there is laboratory evidence for Far-UVC efficacy, there is limited evidence in full-sized rooms. For the first time, we show that Far-UVC deployed in a room-sized chamber effectively inactivates aerosolised Staphylococcus aureus. At a room ventilation rate of 3 air-changes-per-hour (ACH), with 5 filtered-sources the steady-state pathogen load was reduced by 98.4% providing an additional 184 equivalent air changes (eACH). This reduction was achieved using Far-UVC irradiances consistent with current American Conference of Governmental Industrial Hygienists threshold limit values for skin for a continuous 8-h exposure. Our data indicate that Far-UVC is likely to be more effective against common airborne viruses, including SARS-CoV-2, than bacteria and should thus be an effective and "hands-off" technology to reduce airborne disease transmission. The findings provide room-scale data to support the design and development of effective Far-UVC systems.

Deaf community views on paediatric cochlear implantation

There are two models used in the literature to describe those who are d/Deaf: the medical and the cultural models. The medical model describes deafness as an unwanted disability that needs to be treated through the use of medical devices like cochlear implants (CIs). The cultural model describes the word "Deaf" (written with a capital) as a culture and membership of the Deaf community as a privilege. It also places emphasis on the importance of sign language in Deaf culture. Historically, the Deaf community has been opposed to cochlear implantation in children, but little is known about current attitudes, or the attitudes of the Deaf community in New Zealand. This research used an online questionnaire to ask deaf, hard-of-hearing (HoH) and culturally Deaf people in New Zealand about their views on paediatric cochlear implants. Culturally Deaf respondents were compared to those who were not. The study's findings were mixed, suggesting that there are still reservations about the benefits of CIs for children born deaf. It identified key areas for consideration: a bilingual/bicultural approach to CI habilitation in children, and the need to fully inform parents of all of their options. The study also highlighted the multitude of cultural and non-cultural factors that need to be considered in both the decision-making and habilitation processes for treatment of a deaf child. An understanding of how the Deaf community's perspective differs from that of health professions in New Zealand is important in considering what is best for deaf children.

Wavelength-dependent DNA Photodamage in a 3-D Human Skin Model over the far-UVC and Germicidal-UVC Wavelength Ranges from 215 to 255 nm

The effectiveness of UVC to reduce airborne‐mediated disease transmission is well established. However, conventional germicidal UVC (~254 nm) cannot be used directly in occupied spaces because of the potential for damage to the skin and eye. A recently studied alternative with the potential to be used directly in occupied spaces is far UVC (200–235 nm, typically 222 nm), as it cannot penetrate to the key living cells in the epidermis. Optimal far‐UVC use is hampered by limited knowledge of the precise wavelength dependence of UVC‐induced DNA damage, and thus we have used a monochromatic UVC exposure system to assess wavelength‐dependent DNA damage in a realistic 3‐D human skin model. We exposed a 3‐D human skin model to mono‐wavelength UVC exposures of 100 mJ/cm², at UVC wavelengths from 215 to 255 nm (5 nm steps). At each wavelength, we measured yields of DNA‐damaged keratinocytes, and their distribution within the layers of the epidermis. No increase in DNA damage was observed in the epidermis at wavelengths from 215 to 235 nm, but at higher wavelengths (240–255 nm) significant levels of DNA damage was observed. These results support use of far‐UVC radiation to safely reduce the risk of airborne disease transmission in occupied locations.

What is Noise Sensitivity?

Background

Noise sensitivity moderates the association between environmental noise exposure and annoyance and health outcomes.

Methods

In normally hearing adults, we measured noise sensitivity in three ways: using the noise sensitivity questionnaire, a 3-point self-rating, and the loudness discomfort level (LDL; mean reported discomfort level for tone bursts). We then presented recordings of a 15-second 80 dBLAeq aeroplane overflight and participants rated the annoyance and loudness they experienced.

Results

The three measures of noise sensitivity were not well correlated with each other, and only the overall LDL was associated with the ratings of loudness and annoyance in response to the aeroplane sounds.

Conclusions

This implies that our current measures of noise sensitivity may only capture parts of the underlying construct, and therefore underestimate effects due to it on the association between environmental noise and annoyance and health outcomes. We developed a theoretical model to describe the set of factors that may influence a person's sensitivity to noise and propose that interaction between the systems described is the basis for noise sensitivity. This paradigm alters the focus of noise research from the annoyance caused by the sound, to the sensitization to noise that may occur as a result of the interplay of many factors. We hope that our model will allow research to explore the sensitizing factors for noise more easily and systematically.

Music Listening and Homeostatic Regulation: Surviving and Flourishing in a Sonic World

This paper argues for a biological conception of music listening as an evolutionary achievement that is related to a long history of cognitive and affective-emotional functions, which are grounded in basic homeostatic regulation. Starting from the three levels of description, the acoustic description of sounds, the neurological level of processing, and the psychological correlates of neural stimulation, it conceives of listeners as open systems that are in continuous interaction with the sonic world. By monitoring and altering their current state, they can try to stay within the limits of operating set points in the pursuit of a controlled state of dynamic equilibrium, which is fueled by interoceptive and exteroceptive sources of information. Listening, in this homeostatic view, can be adaptive and goal-directed with the aim of maintaining the internal physiology and directing behavior towards conditions that make it possible to thrive by seeking out stimuli that are valued as beneficial and worthy, or by attempting to avoid those that are annoying and harmful. This calls forth the mechanisms of pleasure and reward, the distinction between pleasure and enjoyment, the twin notions of valence and arousal, the affect-related consequences of music listening, the role of affective regulation and visceral reactions to the sounds, and the distinction between adaptive and maladaptive listening.

Improved estimates of 222 nm far-UVC susceptibility for aerosolized human coronavirus via a validated high-fidelity coupled radiation-CFD code

Transmission of SARS-CoV-2 by aerosols has played a significant role in the rapid spread of COVID-19 across the globe. Indoor environments with inadequate ventilation pose a serious infection risk. Whilst vaccines suppress transmission, they are not 100% effective and the risk from variants and new viruses always remains. Consequently, many efforts have focused on ways to disinfect air. One such method involves use of minimally hazardous 222 nm far-UVC light. Whilst a small number of controlled experimental studies have been conducted, determining the efficacy of this approach is difficult because chamber or room geometry, and the air flow within them, influences both far-UVC illumination and aerosol dwell times. Fortunately, computational multiphysics modelling allows the inadequacy of dose-averaged assessment of viral inactivation to be overcome in these complex situations. This article presents the first validation of the WYVERN radiation-CFD code for far-UVC air-disinfection against survival fraction measurements, and the first measurement-informed modelling approach to estimating far-UVC susceptibility of viruses in air. As well as demonstrating the reliability of the code, at circa 70% higher, our findings indicate that aerosolized human coronaviruses are significantly more susceptible to far-UVC than previously thought.

The contribution of personal audio system use and commuting by bus on daily noise dose

Background:

For many young people, exposure to music from personal audio system use may represent a significant component of daily noise dose. Moreover, there is increasing concern for the hearing of those who listen at high volumes. The purpose of this study was to determine the noise levels experienced on commuter buses, and to investigate how these impact on the volume-setting behavior of young adult personal audio system users.

Methods:

A questionnaire was used to probe transport use, personal audio system-listening behaviors and the extent of understanding about noise-induced hearing loss. The influence of bus noise on volume-setting behavior was determined by measuring, in a lab setting, the sound-level preferences of participants when listening to their favorite song, a generic song, or a podcast in the absence and presence of various levels of bus noise, simulated using output-adjusted recordings made of bus noise. Statistical analysis was conducted using analysis of variance.

Results:

While the bus noise itself was below 85 dB Leq, as the sound level of the buses increased, so did the percentage of commuters who were found to exceed the equivalent of 8 hours of exposure at 85 dB Leq.

Implications:

Investment in buses with lower noise levels or the use of noise-canceling or noise-occluding headphones would help to reduce the likelihood of noise-induced hearing loss for bus commuters.

COVID-19 vaccine strategies for Aotearoa New Zealand: a mathematical modelling study

Background: COVID-19 elimination measures, including border closures have been applied in New Zealand. We have modelled the potential effect of vaccination programmes for opening borders. Methods: We used a deterministic age-stratified Susceptible, Exposed, Infectious, Recovered (SEIR) model. We minimised spread by varying the age-stratified vaccine allocation to find the minimum herd immunity requirements (the effective reproduction number R_eff<1 with closed borders) under various vaccine effectiveness (VE) scenarios and R₀ values. We ran two-year open-border simulations for two vaccine strategies: minimising R_eff and targeting high-risk groups. Findings: Targeting of high-risk groups will result in lower hospitalisations and deaths in most scenarios. Reaching the herd immunity threshold (HIT) with a vaccine of 90% VE against disease and 80% VE against infection requires at least 86•5% total population uptake for R₀=4•5 (with high vaccination coverage for 30-49-year-olds) and 98•1% uptake for R₀=6. In a two-year open-border scenario with 10 overseas cases daily and 90% total population vaccine uptake (including 0-15 year olds) with the same vaccine, the strategy of targeting high-risk groups is close to achieving HIT, with an estimated 11,400 total hospitalisations (peak 324 active and 36 new daily cases in hospitals), and 1,030 total deaths. Interpretation: Targeting high-risk groups for vaccination will result in fewer hospitalisations and deaths with open borders compared to targeting reduced transmission. With a highly effective vaccine and a high total uptake, opening borders will result in increasing cases, hospitalisations, and deaths. Other public health and social measures will still be required as part of an effective pandemic response. Funding: This project was funded by the Health Research Council [20/1018]. Research in context.

Real-Time Genomics for Tracking Severe Acute Respiratory Syndrome Coronavirus 2 Border Incursions after Virus Elimination, New Zealand

Since severe acute respiratory syndrome coronavirus 2 was first eliminated in New Zealand in May 2020, a total of 13 known coronavirus disease (COVID-19) community outbreaks have occurred, 2 of which led health officials to issue stay-at-home orders. These outbreaks originated at the border via isolating returnees, airline workers, and cargo vessels. Because a public health system was informed by real-time viral genomic sequencing and complete genomes typically were available within 12 hours of community-based positive COVID-19 test results, every outbreak was well-contained. A total of 225 community cases resulted in 3 deaths. Real-time genomics were essential for establishing links between cases when epidemiologic data could not do so and for identifying when concurrent outbreaks had different origins.

Novel Integrative Modeling of Molecules and Morphology across Evolutionary Timescales

Evolutionary models account for either population- or species-level processes but usually not both. We introduce a new model, the FBD-MSC, which makes it possible for the first time to integrate both the genealogical and fossilization phenomena, by means of the multispecies coalescent (MSC) and the fossilized birth–death (FBD) processes. Using this model, we reconstruct the phylogeny representing all extant and many fossil Caninae, recovering both the relative and absolute time of speciation events. We quantify known inaccuracy issues with divergence time estimates using the popular strategy of concatenating molecular alignments and show that the FBD-MSC solves them. Our new integrative method and empirical results advance the paradigm and practice of probabilistic total evidence analyses in evolutionary biology.[Caninae; fossilized birth–death; molecular clock; multispecies coalescent; phylogenetics; species trees.]

Use of Genomics to Track Coronavirus Disease Outbreaks, New Zealand

Real-time genomic sequencing has played a major role in tracking the global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), contributing greatly to disease mitigation strategies. In August 2020, after having eliminated the virus, New Zealand experienced a second outbreak. During that outbreak, New Zealand used genomic sequencing in a primary role, leading to a second elimination of the virus. We generated genomes from 78% of the laboratory-confirmed samples of SARS-CoV-2 from the second outbreak and compared them with the available global genomic data. Genomic sequencing rapidly identified that virus causing the second outbreak in New Zealand belonged to a single cluster, thus resulting from a single introduction. However, successful identification of the origin of this outbreak was impeded by substantial biases and gaps in global sequencing data. Access to a broader and more heterogenous sample of global genomic data would strengthen efforts to locate the source of any new outbreaks.

Phylodynamics reveals the role of human travel and contact tracing in controlling the first wave of COVID-19 in four island nations

New Zealand, Australia, Iceland, and Taiwan all saw success in controlling their first waves of Coronavirus Disease 2019 (COVID-19). As islands, they make excellent case studies for exploring the effects of international travel and human movement on the spread of COVID-19. We employed a range of robust phylodynamic methods and genome subsampling strategies to infer the epidemiological history of Severe acute respiratory syndrome coronavirus 2 in these four countries. We compared these results to transmission clusters identified by the New Zealand Ministry of Health by contact tracing strategies. We estimated the effective reproduction number of COVID-19 as 1-1.4 during early stages of the pandemic and show that it declined below 1 as human movement was restricted. We also showed that this disease was introduced many times into each country and that introductions slowed down markedly following the reduction of international travel in mid-March 2020. Finally, we confirmed that New Zealand transmission clusters identified via standard health surveillance strategies largely agree with those defined by genomic data. We have demonstrated how the use of genomic data and computational biology methods can assist health officials in characterising the epidemiology of viral epidemics and for contact tracing.

Exposure of Human Skin Models to KrCl Excimer Lamps: The Impact of Optical Filtering†

Far‐UVC radiation is a promising technology that is potentially both effective at killing airborne microbes such as coronaviruses and influenza, and being minimally hazardous to the skin and eyes. Our previous studies on health risks from far‐UVC have employed a krypton‐chloride (KrCl) excimer lamp, emitting principally at 222 nm, supplemented with an optical filter to remove longer wavelength emissions inherent to these lamps. This study explores KrCl lamp health hazards by comparing filtered and unfiltered KrCl lamps using effective spectral irradiance calculations and experimental skin exposures. Analysis of effective irradiances showed a notable increase in allowable exposure when using a filter. Induction of DNA dimers (CPD and 6‐4PP) was measured in human skin models exposed to a range of radiant exposures up to 500 mJ cm⁻². Compared to sham‐exposed tissues, the unfiltered KrCl lamps induced a statistically significant increase in the yield of both DNA lesions at all the radiant exposures studied. Conversely, filtered KrCl lamps do not induce increased levels of dimers at the current daily TLV exposure limit for 222 nm (23 mJ cm⁻²). This work supports the use of filters for far‐UVC KrCl excimer lamps when used to limit disease transmission in occupied locations.

Genomic Evidence of In-Flight Transmission of SARS-CoV-2 Despite Predeparture Testing

Since the first wave of coronavirus disease in March 2020, citizens and permanent residents returning to New Zealand have been required to undergo managed isolation and quarantine (MIQ) for 14 days and mandatory testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As of October 20, 2020, of 62,698 arrivals, testing of persons in MIQ had identified 215 cases of SARS-CoV-2 infection. Among 86 passengers on a flight from Dubai, United Arab Emirates, that arrived in New Zealand on September 29, test results were positive for 7 persons in MIQ. These passengers originated from 5 different countries before a layover in Dubai; 5 had negative predeparture SARS-CoV-2 test results. To assess possible points of infection, we analyzed information about their journeys, disease progression, and virus genomic data. All 7 SARS-CoV-2 genomes were genetically identical, except for a single mutation in 1 sample. Despite predeparture testing, multiple instances of in-flight SARS-CoV-2 transmission are likely.

Improved Ultraviolet Radiation Film Dosimetry Using OrthoChromic OC-1 Film†

There is growing interest in far-UVC lighting, defined as wavelengths from 200 to 230 nm, because research has demonstrated these wavelengths to be an effective antimicrobial technology while posing a minimal hazard to human health. Far-UVC lighting is now being installed to directly irradiate spaces where humans are present, and it will be important to perform measurements to verify far-UVC lighting installations are operating within widely accepted exposure guidelines. In this work, we explore the use of a commercially available film, known as OrthoChromic OC-1, to measure ultraviolet radiation exposure. The film was tested with a variety of ultraviolet wavelengths and irradiance conditions, and the color change of the film was analyzed for increasing levels of radiant exposure. The film response extended over a dynamic range that was greater than the recommended exposure limits for far-UVC radiation so it can potentially be useful for health hazard monitoring. The spectrum of the incident ultraviolet radiation strongly affected the response of the film; therefore, for accurate measurements we recommend the measured spectrum match the spectrum used for calibration. Overall, dosimetry with this film provides a simple, accurate, and inexpensive method of quantifying ultraviolet radiation exposure that is suitable for far-UVC measurements.

Proton Irradiation Platforms for Preclinical Studies of High-Dose-Rate (FLASH) Effects at RARAF

Limited availability of proton irradiators optimized for high-dose-rate studies makes the preclinical research of proton FLASH therapy challenging. We assembled two proton irradiation platforms that are capable of delivering therapeutic doses to thin biological samples at dose rates equal to and above 100 Gy/s. We optimized and tested dosimetry protocols to assure accurate dose delivery regardless of the instantaneous dose rate. The simplicity of the experimental setups and availability of custom-designed sample holders allows these irradiation platforms to be easily adjusted to accommodate different types of samples, including cell monolayers, 3D tissue models and small animals. We have also fabricated a microfluidic flow-through device for irradiations of biological samples in suspension. We present one example of a measurement with accompanying preliminary results for each of the irradiation platforms. One irradiator was used to study the role of proton dose rate on cell survival for three cancer cell lines, while the other was used to investigate the depletion of oxygen from an aqueous solution by water radiolysis using short intense proton pulses. No dose-rate-dependent variation was observed between the survival fractions of cancer cells irradiated at dose rates of 0.1, 10 and 100 Gy/s up to 10 Gy. On the other hand, irradiations of Fricke solution at 1,000 Gy/s indicated full depletion of oxygen after proton doses of 107 Gy and 56 Gy for samples equilibrated with 21% and 4% oxygen, respectively.

Differential Immune Modulation With Carbon-Ion Versus Photon Therapy

PURPOSE

Radiation therapy (RT) modulates the immune characteristics of the tumor microenvironment (TME). It is not known whether these effects are dependent on the type of RT used.

METHODS AND MATERIALS

We evaluated the immunomodulatory effects of carbon-ion therapy (CiRT) compared with biologically equivalent doses of photon therapy (PhRT) on solid tumors. Orthotopic 4T1 mammary tumors in immunocompetent hosts were treated with CiRT or biologically equivalent doses of PhRT. Seventy-two hours after RT, tumors were harvested and the immune characteristics of the TME were quantified by flow cytometry and multiplex cytokine analyses.

RESULTS

PhRT decreased the abundance of CD4+ and CD8+ T cells in the TME at all doses tested, with compensatory increases in proliferation. By contrast, CiRT did not significantly alter CD8+ T-cell infiltration. High-dose CiRT increased secretion of proinflammatory cytokines by tumor-infiltrating CD8+ T cells, including granzyme B, IL-2, and TNF-α, with no change in IFN-γ. Conversely, high-dose PhRT increased CD8+ T-cell secretion of IFN-γ only. At most of the doses studied, PhRT increased proliferation of immunosuppressive regulatory T cells; this was only seen with high-dose CiRT. Cytokine analyses of bulk dissociated tumors showed that CiRT significantly increased levels of IFN-γ, IL-2, and IL-1β, whereas PhRT increased IL-6 levels alone.

CONCLUSIONS

At low doses, lymphocytes differ in their sensitivity to CiRT compared with PhRT. Unlike PhRT, low-dose CiRT is generally lymphocyte-sparing. At higher doses, CiRT is a more potent inducer of proinflammatory cytokines and merits further study as a modulator of the immunologic characteristics of the TME.

The Epidemiology of Noise Sensitivity in New Zealand

BACKGROUND

Sensitivity to noise, or nuisance sounds that interrupt relaxation and task-related activities, has been shown to vary significantly across individuals. The current study sought to uncover predictors of noise sensitivity, focussing on possible social and cultural determinants, including social position, education, ethnicity, gender, and the presence of an illness.

METHOD

Data were collected from 746 New Zealand adults residing in 6 areas differentiated by social position. Participants responded to questions probing personal characteristics, noise sensitivity, illness, neighbourhood problems, and noise annoyance. It was hypothesized that those in high-deprivation areas and/or experiencing illness report higher levels of noise sensitivity.

RESULTS

Approximately 50 and 10% of the participants reported being moderately or very noise sensitive, respectively. Significant predictors of noise sensitivity included age, length of residence, level of social deprivation, and self-reported illness.

CONCLUSION

There is evidence of social determinants of noise sensitivity, including social position and residential factors.

Music Listening as Coping Behavior: From Reactive Response to Sense-Making

Coping is a survival mechanism of living organisms. It is not merely reactive, but also involves making sense of the environment by rendering sensory information into percepts that have meaning in the context of an organism's cognitions. Music listening, on the other hand, is a complex task that embraces sensory, physiological, behavioral, and cognitive levels of processing. Being both a dispositional process that relies on our evolutionary toolkit for coping with the world and a more elaborated skill for sense-making, it goes beyond primitive action-reaction couplings by the introduction of higher-order intermediary variables between sensory input and effector reactions. Consideration of music-listening from the perspective of coping treats music as a sound environment and listening as a process that involves exploration of this environment as well as interactions with the sounds. Several issues are considered in this regard such as the conception of music as a possible stressor, the role of adaptive listening, the relation between coping and reward, the importance of self-regulation strategies in the selection of music, and the instrumental meaning of music in the sense that it can be used to modify the internal and external environment of the listener.

Estimating Epidemic Incidence and Prevalence from Genomic Data

Modern phylodynamic methods interpret an inferred phylogenetic tree as a partial transmission chain providing information about the dynamic process of transmission and removal (where removal may be due to recovery, death, or behavior change). Birth–death and coalescent processes have been introduced to model the stochastic dynamics of epidemic spread under common epidemiological models such as the SIS and SIR models and are successfully used to infer phylogenetic trees together with transmission (birth) and removal (death) rates. These methods either integrate analytically over past incidence and prevalence to infer rate parameters, and thus cannot explicitly infer past incidence or prevalence, or allow such inference only in the coalescent limit of large population size. Here, we introduce a particle filtering framework to explicitly infer prevalence and incidence trajectories along with phylogenies and epidemiological model parameters from genomic sequences and case count data in a manner consistent with the underlying birth–death model. After demonstrating the accuracy of this method on simulated data, we use it to assess the prevalence through time of the early 2014 Ebola outbreak in Sierra Leone.

Forensic STR allele extraction using a machine learning paradigm

We present a machine learning approach to short tandem repeat (STR) sequence detection and extraction from massively parallel sequencing data called Fragsifier. Using this approach, STRs are detected on each read by first locating the longest repeat stretches followed by locus prediction using k-mers in a machine learning sequence model. This is followed by reference flanking sequence alignment to determine precise STR boundaries. We show that Fragsifier produces genotypes that are concordant with profiles obtained using capillary electrophoresis (CE), and also compared the results with that of STRait Razor and the ForenSeq UAS. The data pre-processing and training of the sequence classifier is readily scripted, allowing the analyst to experiment with different thresholds, datasets and loci of interest, and different machine learning models.

Identifying hearing care access barriers among older Pacific Island people in New Zealand: a qualitative study

OBJECTIVES

Hearing loss is one of the most prevalent conditions affecting older people. In addition, there is little known about the factors influencing the uptake of hearing services among underserved communities. Our objective was to identify the barriers to accessing hearing care services among older Pacific Island people in New Zealand.

SETTINGS

Eligible participants from Auckland City, New Zealand.

PARTICIPANTS

Individual face-to-face in-depth interviews were conducted with 36 older Pacific Island people who were experienced hearing difficulties.

METHODS

A Pacific Island research methodology (Talanoa) and the 'Health Care Access Barriers' (HCAB) model, which identifies modifiable barriers to healthcare, was used as a theoretical framework for this research. The interviews were transcribed and analysed using a deductive approach to identify HCAB themes and subthemes experienced by older Pacific Island people.

RESULTS

Identified themes aligned with HCAB's themes of financial, structural and cognitive barriers and subthemes described Pacific Island perspectives related to hearing care access in New Zealand. The financial barriers related to the high cost of hearing care and the structural barriers included transportation difficulties, limited family support, preference for community-based services and the absence of hearing care delivered by family doctors. Community norms and attitudes, communication limitations and limited awareness of hearing care services formed cognitive barriers among older Pasifika people in this study.

CONCLUSION

We identified financial, structural and cognitive barriers that dissuaded older Pasifika people from accessing hearing care services. These modifiable barriers need to be eliminated or minimised to enable people to readily receive the hearing care assistance they need. It is essential to improve and develop culturally responsive models of hearing service delivery to ensure equitable access to hearing care, especially for underserved groups such as Pacific Island communities.

Music and Noise: Same or Different? What Our Body Tells Us

In this article, we consider music and noise in terms of vibrational and transferable energy as well as from the evolutionary significance of the hearing system of Homo sapiens. Music and sound impinge upon our body and our mind and we can react to both either positively or negatively. Much depends, in this regard, on the frequency spectrum and the level of the sound stimuli, which may sometimes make it possible to set music apart from noise. There are, however, two levels of description: the physical-acoustic description of the sound and the subjective-psychological reactions by the listeners. Starting from a vibrational approach to sound and music, we first investigate how sound may activate the sense of touch and the vestibular system of the inner ear besides the sense of hearing. We then touch upon distinct issues such as the relation between low-frequency sounds and annoyance, the harmful effect of loud sound and noise, the direct effects of overstimulation with sound, the indirect effects of unwanted sounds as related to auditory neurology, and the widespread phenomenon of liking loud sound and music, both from the point of view of behavioral and psychological aspects.

Use of Creative Writing to Develop a Semantic Differential Tool for Assessing Soundscapes

Exploring our understanding of soundscapes to understand why and how sound impacts people is important. The aim of this study was to develop a short quantitative questionnaire that would use terms generated by creative writers to assess people’s experiences of a soundscape. This process may provide different items for the questionnaire and thus, potentially, different dimensions or fuller definitions of dimensions that have already been identified. In the preliminary phase, a group of people identifying themselves as good writers listened to recordings of natural, traffic, and human sound environments and wrote about their impressions and responses to each. Qualitative analysis was used to extract themes from the writing. These themes were identified by key words, and scalar items were developed to form a short 17-item questionnaire. The questionnaire was administered to 228 people in Auckland City, New Zealand, with participants recruited from city streets and in a central-city park. Respondents were comfortable to use the questionnaire. Factor analysis revealed patterns of responding with five dimensions: Calming, Protecting, Hectic, Belonging, and Stability. There were correspondences between these and others previously reported in the literature, as well as differences. The use of items derived from creative writing provided interesting insights into the soundscape, including spirituality, the sense of time passing, and physical wellbeing. The park soundscape was measurably better than the street soundscapes on all dimensions, and streets with less vehicular traffic tended to be experienced as more Calming and Protecting, and less Hectic. This implies that there is validity in the scales generated. In future, it would be valuable to test the questionnaire in more varied environments, to add greater variability to the soundscapes.

Health-related quality of life is impacted by proximity to an airport in noise-sensitive people

INTRODUCTION

The aim of the study was to determine whether those who are noise sensitive are more adversely affected by airport noise than those who are not noise sensitive.

PARTICIPANTS AND METHODS

One area was very close to Wellington International Airport and the other was distant from the airport and any other major sources of noise such as motorways and railways. Noise sensitivity was self-rated on a three-point scale as follows: non-noise sensitive, moderately noise sensitive, or highly noise sensitive. Statistical analysis consisted of analyses of variance using the domains of the WHOQOL score with the year, area (airport or the control), and noise sensitivity as covariates.

RESULTS

Noise-sensitive people were found to have a significantly poorer HRQOL than others when they lived near an airport, but not when they lived in the control area. The same effect was present at both of the time points investigated, suggesting that it is a general finding.

DISCUSSION

This finding is consistent with similar studies using the WHOQOL-BREF for investigating noise from road traffic, suggesting consistency in effect across transport noise sources.

Effect of far ultraviolet light emitted from an optical diffuser on methicillin-resistant Staphylococcus aureus in vitro

Drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) are a target for new antimicrobial technologies. Far-UVC technology is an emerging disinfection method that directly kills microorganisms using light. In contrast with conventional UV sterilization, far-UVC light has antimicrobial capabilities without apparent harm to mammalian cells. This study examines the application of 224 nm far-UVC light delivered from a laser using an optical diffuser towards the goal of protecting against bacterial invasion around skin penetrating devices. Delivery of far-UVC using a laser and optical fibers enables exposure to unique geometries that would otherwise be shielded when using a lamp. Testing of the bactericidal potential of diffusing the far-UVC laser output over a large area was tested and yielded qualitative area killing results. The killing of MRSA using this method was also examined using an in vitro survival assay. Results followed a classic log-linear disinfection model with a rate constant of k = 0.51 cm2/mJ, which corresponds to an inactivation cross section of D90 = 4.5 mJ/cm2. This study establishes far-UVC delivered from a laser through an optical diffuser as a viable solution for disinfection of susceptible regions such as around catheters, drivelines, or other skin penetrating medical devices.

The Evolution of Soundscape Appraisal Through Enactive Cognition

We propose a framework based on evolutionary principles and the theory of enactive cognition ("being by doing"), that addresses the foundation of key results and central questions of soundscape research. We hypothesize that the two main descriptors (measures of how people perceive the acoustic environment) of soundscape appraisal ('pleasantness' and 'eventfulness'), reflect evolutionarily old motivational and affective systems that promote survival through preferences for certain environments and avoidance of others. Survival is aimed at ending or avoiding existential threats and protecting viability in a deficient environment. On the other hand, flourishing occurs whenever survival is not an immediate concern and aims to improve the agent's viability and by co-creating ever better conditions for existence. As such, survival is experienced as unpleasant, and deals with immediate problems to be ended or avoided, while flourishing is enjoyable, and therefore to be aimed for and maintained. Therefore, the simplest, safety-relevant meaning attributable to soundscapes (audible safety) should be key to understanding soundscape appraisal. To strengthen this, we show that the auditory nervous system is intimately connected to the parts of our brains associated with arousal and emotions. Furthermore, our theory demonstrates that 'complexity' and 'affordance content' of the perceived environment are important underlying soundscape indicators (measures used to predict the value of a soundscape descriptor). Consideration of these indicators allows the same soundscape to be viewed from a second perspective; one driven more by meaning attribution characteristics than merely emotional appraisal. The synthesis of both perspectives of the same person-environment interaction thus consolidates the affective, informational, and even the activity related perspectives on soundscape appraisal. Furthermore, we hypothesize that our current habitats are not well matched to our, evolutionarily old, auditory warning systems, and that we consequently have difficulty establishing audible safety. This leads to more negative and aroused moods and emotions, with stress-related symptoms as a result.

Far-UVC light prevents MRSA infection of superficial wounds in vivo

Background

Prevention of superficial surgical wound infections from drug-resistant bacteria such as methicillin resistant Staphylococcus aureus (MRSA) currently present major health care challenges. The majority of surgical site infections (SSI) are believed to be caused by airborne transmission of bacteria alighting onto the wound during surgical procedures. We have previously shown that far-ultraviolet C light in the wavelength range of 207–222 nm is significantly harmful to bacteria, but without damaging mammalian cells and tissues. It is important that the lamp be fitted with a filter to remove light emitted at wavelengths longer than 230 nm which are harmful.

Aims

Using a hairless mouse model of infection of superficial wounds, here we tested the hypothesis that 222-nm light kills MRSA alighting onto a superficial skin incisions as efficiently as typical germicidal light (254 nm), but without inducing skin damage.

Methods

To simulate the scenario wherein incisions are infected during surgical procedures as pathogens in the room alight on a wound, MRSA was spread on a defined area of the mouse dorsal skin; the infected skin was then exposed to UVC light (222 nm or 254 nm) followed by a superficial incision within the defined area, which was immediately sutured. Two and seven days post procedure, bactericidal efficacy was measured as MRSA colony formation unit (CFU) per gram of harvested skin whereas fixed samples were used to assess skin damage measured in terms of epidermal thickness and DNA photodamage.

Results

In the circumstance of superficial incisions infected with bacteria alighting onto the wound, 222-nm light showed the same bactericidal properties of 254-nm light but without the associated skin damage.

Conclusions

Being safe for patient and hospital staff, our results suggested that far-UVC light (222 nm) might be a convenient approach to prevent transmission of drug-resistant infectious agents in the clinical setting.