A Novel VOC Breath Tracer Method to Evaluate Indoor Respiratory Exposures in the Near- and far-fields; implications for the spread of respiratory viruses

Background Several studies suggest that far-field transmission (\u3e6 ft) explains a significant number of COVID-19 superspreading outbreaks. Objective Therefore, quantifying the ratio of near- and far-field exposure to emissions from a source is key to better understanding human-to-human airborne infectious disease transmission and associated risks. Methods In this study, we used an environmentally-controlled chamber to measure volatile organic compounds (VOCs) released from a healthy participant who consumed breath mints, which contained unique tracer compounds. Tracer measurements were made at 0.76 m (2.5 ft), 1.52 m (5 ft), 2.28 m (7.5 ft) from the participant, as well as in the exhaust plenum of the chamber. Results We observed that 0.76 m (2.5 ft) trials had ~36–44% higher concentrations than other distances during the first 20 minutes of experiments, highlighting the importance of the near-field exposure relative to the far-field before virus-laden respiratory aerosol plumes are continuously mixed into the far-field. However, for the conditions studied, the concentrations of human-sourced tracers after 20 minutes and approaching the end of the 60-minute trials at 0.76 m, 1.52 m, and 2.28 m were only ~18%, ~11%, and ~7.5% higher than volume-averaged concentrations, respectively. Significance This study suggests that for rooms with similar airflow parameters disease transmission risk is dominated by near-field exposures for shorter event durations (e.g., initial 20–25-minutes of event) whereas far-field exposures are critical throughout the entire event and are increasingly more important for longer event durations

Monitored Indoor Environmental Quality of a Mass Timber Office Building: A Case Study

A broad range of building performance monitoring, sampling, and evaluation was conducted periodically after construction and spanning more than a year, for an occupied office building constructed using mass timber elements such as cross-laminated timber (CLT) floor and roof panels, as well as glue-laminated timber (GLT) beams and columns. This case study contributes research on monitoring indoor environmental quality in buildings, describing one of the few studies of an occupied mass timber building, and analyzing data in three areas that impact occupant experience: indoor air quality, bacterial community composition, and floor vibration. As a whole, the building was found to perform well. Volatile organic compounds (VOCs), including formaldehyde, were analyzed using multiple methods. Formaldehyde was found to be present in the building, though levels were below most recommended exposure limits. The source of formaldehyde was not able to be identified in this study. The richness of the bacterial community was affected by the height of sampling with respect to the floor, and richness and composition was aected by the location within the building. Floor vibration was observed to be below recognized human comfort thresholds

Effects of eight neuropsychiatric copy number variants on human brain structure

Many copy number variants (CNVs) confer risk for the same range of neurodevelopmental symptoms and psychiatric conditions including autism and schizophrenia. Yet, to date neuroimaging studies have typically been carried out one mutation at a time, showing that CNVs have large effects on brain anatomy. Here, we aimed to characterize and quantify the distinct brain morphometry effects and latent dimensions across 8 neuropsychiatric CNVs. We analyzed T1-weighted MRI data from clinically and non-clinically ascertained CNV carriers (deletion/duplication) at the 1q21.1 (n = 39/28), 16p11.2 (n = 87/78), 22q11.2 (n = 75/30), and 15q11.2 (n = 72/76) loci as well as 1296 non-carriers (controls). Case-control contrasts of all examined genomic loci demonstrated effects on brain anatomy, with deletions and duplications showing mirror effects at the global and regional levels. Although CNVs mainly showed distinct brain patterns, principal component analysis (PCA) loaded subsets of CNVs on two latent brain dimensions, which explained 32 and 29% of the variance of the 8 Cohen’s d maps. The cingulate gyrus, insula, supplementary motor cortex, and cerebellum were identified by PCA and multi-view pattern learning as top regions contributing to latent dimension shared across subsets of CNVs. The large proportion of distinct CNV effects on brain morphology may explain the small neuroimaging effect sizes reported in polygenic psychiatric conditions. Nevertheless, latent gene brain morphology dimensions will help subgroup the rapidly expanding landscape of neuropsychiatric variants and dissect the heterogeneity of idiopathic conditions

DNA Fingerprinting

The purpose of this IQP was to examine the fundamental principles of DNA fingerprinting technology, analyzing its growth within both the legal and scientific communities, to provide an effective documentation of the impact of this new technology on society. Various methods used to obtain DNA fingerprints were analyzed, including the proper techniques for handling and storing DNA samples. Several court cases using DNA forensics were explored to document the technical proceedings involved in admittance of DNA evidence into U.S courts. A few court cases of popular notoriety were covered to give readers a frame of reference for DNA fingerprinting and forensics within the media and current events. Ethical issues of privacy stemming from the advent of DNA forensics and databases were examined

A novel VOC breath tracer method to evaluate indoor respiratory exposures in the near- and far-fields; implications for the spread of respiratory viruses

BackgroundSeveral studies suggest that far-field transmission (>6 ft) explains a significant number of COVID-19 superspreading outbreaks.ObjectiveTherefore, quantifying the ratio of near- and far-field exposure to emissions from a source is key to better understanding human-to-human airborne infectious disease transmission and associated risks.MethodsIn this study, we used an environmentally-controlled chamber to measure volatile organic compounds (VOCs) released from a healthy participant who consumed breath mints, which contained unique tracer compounds. Tracer measurements were made at 0.76 m (2.5 ft), 1.52 m (5 ft), 2.28 m (7.5 ft) from the participant, as well as in the exhaust plenum of the chamber.ResultsWe observed that 0.76 m (2.5 ft) trials had ~36-44% higher concentrations than other distances during the first 20 minutes of experiments, highlighting the importance of the near-field exposure relative to the far-field before virus-laden respiratory aerosol plumes are continuously mixed into the far-field. However, for the conditions studied, the concentrations of human-sourced tracers after 20 minutes and approaching the end of the 60-minute trials at 0.76 m, 1.52 m, and 2.28 m were only ~18%, ~11%, and ~7.5% higher than volume-averaged concentrations, respectively.SignificanceThis study suggests that for rooms with similar airflow parameters disease transmission risk is dominated by near-field exposures for shorter event durations (e.g., initial 20-25-minutes of event) whereas far-field exposures are critical throughout the entire event and are increasingly more important for longer event durations.Impact statementWe offer a novel methodology for studying the fate and transport of airborne bioaerosols in indoor spaces using VOCs as unique proxies for bioaerosols. We provide evidence that real-time measurement of VOCs can be applied in settings with human subjects to estimate the concentration of bioaerosol at different distances from the emitter. We also improve upon the conventional assumption that a well-mixed room exhibits instantaneous and perfect mixing by addressing spatial distances and mixing over time. We quantitatively assessed the exposure levels to breath tracers at alternate distances and provided more insights into the changes on "near-field to far-field" ratios over time. This method can be used in future to estimate the benefits of alternate environmental conditions and occupant behaviors

Overall and metastasis‐free survival of Afro‐Caribbean patients with biochemical recurrence after radical prostatectomy

International audienceIntroduction: Early salvage radiotherapy is indicated for patients with biochemical recurrence after radical prostatectomy. However, for various reasons, certain patients do not benefit from this treatment (OBS) or only at a late stage (LSR). There are few studies on this subject and none on a \"high-risk\" population, such as patients of African descent. Our objective was to estimate the metastasis-free (MFS) and overall survival (OS) of patients who did not receive salvage radiotherapy, and to identify risk factors of disease progression.Patients and methods: This was a single-center retrospective study that included 154 patients, 99 in the OBS group and 55 in the LSR group. All were treated by total prostatectomy for localized prostate cancer between January 2000 and December 2020 and none received early salvage radiotherapy after biochemical recurrence.Results: Baseline characteristics were similar between groups, except for the time to biochemical recurrence. The median follow-up was 10.0 and 11.8 years for the OBS and LSR groups, respectively. The median time from surgery to LSR was 5.1 years. The two groups did not show a significant difference in MFS: 90.6% at 10 years for the OBS group and 93.3% for the LSR group. The median MFS was 19.8 and 19.6 years for the OBS and LSR groups respectively. OS for the OBS group was significantly higher than that for the LSR group (HR: 2.14 [1.07-4.29]; p = 0.03), with 10-year OS of 95.9% for the OBS group and 76.1% for the LSR group. Median OS was 16 and 15.6 years for the OBS and LSR groups, respectively.Conclusion: In this study, we observed satisfactory metastasis-free and OS rates relative to those reported in the scientific literature. The challenge is not to question the benefit of early salvage radiotherapy, but to improve the identification of patients at risk of progression through the development of molecular and genomic tests for more highly personalized medicine

Differing effects of four building materials on viable bacterial communities and VOCs

16 pagesIndoor environmental quality is a paramount concern among architects. Exposure to VOCs and microorganisms impacts occupant health, yet the role of materials on these exposures remains poorly understood. In this study, we placed four material types in individual microcosms to test whether material type influences bacterial community structure and VOC emission. We used culture-independent methods to characterize bacterial communities and TD-GC-MS to measure VOC emission. We found that viable bacterial communities had different patterns of abundance, diversity, and composition, in comparison with total (viable plus dead cells) bacterial communities. Examining viable bacteria only, Earth had the highest abundance and diversity, unique community composition, and overall negative VOC emission. Timber had the lowest bacterial abundance, composition similar to Gypsum and Concrete, and the highest VOC emission rate. Our research provides further evidence that architects’ decisions about building materials can influence chemical and microbial exposures indoors