Socioeconomic Adversity and Weight Gain During the COVID-19 Pandemic.

This cohort study uses a natural experimental design to assess the impact of the COVID-19 lockdown on weight gain as associated with socioeconomic disadvantage in a diverse population of US youth.

The mouse cortico-basal ganglia-thalamic network.

The cortico-basal ganglia-thalamo-cortical loop is one of the fundamental network motifs in the brain. Revealing its structural and functional organization is critical to understanding cognition, sensorimotor behaviour, and the natural history of many neurological and neuropsychiatric disorders. Classically, this network is conceptualized to contain three information channels: motor, limbic and associative1-4. Yet this three-channel view cannot explain the myriad functions of the basal ganglia. We previously subdivided the dorsal striatum into 29 functional domains on the basis of the topography of inputs from the entire cortex5. Here we map the multi-synaptic output pathways of these striatal domains through the globus pallidus external part (GPe), substantia nigra reticular part (SNr), thalamic nuclei and cortex. Accordingly, we identify 14 SNr and 36 GPe domains and a direct cortico-SNr projection. The striatonigral direct pathway displays a greater convergence of striatal inputs than the more parallel striatopallidal indirect pathway, although direct and indirect pathways originating from the same striatal domain ultimately converge onto the same postsynaptic SNr neurons. Following the SNr outputs, we delineate six domains in the parafascicular and ventromedial thalamic nuclei. Subsequently, we identify six parallel cortico-basal ganglia-thalamic subnetworks that sequentially transduce specific subsets of cortical information through every elemental node of the cortico-basal ganglia-thalamic loop. Thalamic domains relay this output back to the originating corticostriatal neurons of each subnetwork in a bona fide closed loop.

Connectivity characterization of the mouse basolateral amygdalar complex.

The basolateral amygdalar complex (BLA) is implicated in behaviors ranging from fear acquisition to addiction. Optogenetic methods have enabled the association of circuit-specific functions to uniquely connected BLA cell types. Thus, a systematic and detailed connectivity profile of BLA projection neurons to inform granular, cell type-specific interrogations is warranted. Here, we apply machine-learning based computational and informatics analysis techniques to the results of circuit-tracing experiments to create a foundational, comprehensive BLA connectivity map. The analyses identify three distinct domains within the anterior BLA (BLAa) that house target-specific projection neurons with distinguishable morphological features. We identify brain-wide targets of projection neurons in the three BLAa domains, as well as in the posterior BLA, ventral BLA, posterior basomedial, and lateral amygdalar nuclei. Inputs to each nucleus also are identified via retrograde tracing. The data suggests that connectionally unique, domain-specific BLAa neurons are associated with distinct behavior networks.

Comparison and evaluation of a high volume air sampling system for the collection of Clostridioides difficile endospore aerosol in health care environments.

BACKGROUND: Environmental contamination of patient rooms and adjacent areas with C. difficile spores is a recognized transmission risk. Previous studies have shown that spores are aerosolized during patient care. These spores can remain airborne for extended periods and may contaminate distant surfaces. High-volume air sampling equipment allows for the collection of a large volume of air and was evaluated in the collection of C. difficile aerosol. METHOD: Air samplers evaluated in this research included the DFU-1000, XMX/2L-MIL, Biocapture-650, and a MB2. Aerosols of C. difficile were generated in a 5-m3 chamber and each air sampler sampled in the aerosol test chamber simultaneously with referee air samplers. RESULTS: The DFU-1000 achieved the highest efficiency of the 4 air samplers (P = .0145) with a mean efficiency of 38.60%. The relative efficiencies of the Biocapture-650, XMX/2L-MIL, and MB2 were 28.16%, 10.51%, and 3.05%, respectively. DISCUSSION/CONCLUSIONS: This study demonstrated high variation based on the sampling method employed. Based on the results of these studies, high-volume air samplers may be effectively applied to sample for airborne C. difficile in health care environments. The high sampling flow rate of the DFU-1000 would allow for the complete sampling of a patient room-sized volume in less than 1 hour.

Low powered variable voltage E-Cigarette batteries under perform at higher power settings.

Objective: Electronic Cigarettes (EC) use continues to increase with many efforts underway to develop dose-response relationships for clinical and sub-clinical purposes. This study investigated the battery performance of several variable voltage (VV) ECs capable of varied voltage outputs.Materials and Methods: Six brands of VV EC batteries were tested for dial setting accuracy (voltage) and power supplied during simulated vaping. All measurements were conducted using a single atomizer with two different resistance coils at four voltage settings in a blocked randomized structure. Battery dial settings were accurate when disconnected from an atomizer.Results: When powering an atomizer during simulated vaping, all batteries supplied power linearly up to approximately 8.5 watts. Beyond 8.5 watts all batteries began to undersupply power, plateauing around 9-10 watts, depending on the specific battery.Discussion: This behavior was not consistent with battery internal resistance. Undersupply of power at higher device settings will result in lower-than-expected nicotine (or THC) delivery and potentially lower pyrolysis products such as aldehydes.Conclusion: Studies seeking to associate VV EC power with psychological, physiological or toxicological effects should measure the actual power supplied or else a negative bias is likely to be observed in trials above 8.5 watts.

E-cigarette nicotine deposition and persistence on glass and cotton surfaces.

Nicotine from electronic cigarette aerosol will deposit on surfaces immediately after vaping, but how long deposited nicotine will persist on various surfaces is unknown. This work exposed glass and terrycloth (cotton) materials to electronic cigarette aerosols for 1 hr, assessed the initial nicotine sorption, and characterized surface persistence over a 72-hr period. Exponential decay of surface concentration was observed for both materials. Terrycloth had higher initial nicotine deposition and retained nicotine substantially longer than glass. Residual nicotine concentrations persisted on both surface types for 72 hr. Statistical modeling predicted surface concentrations to reach background levels after 4 and 16 days for glass and terrycloth, respectively. Nicotine persistence was long enough to pose a potential thirdhand nicotine exposure risk, and reactions to produce tobacco-specific nitrosamines may be possible from nicotine deposition from electronic cigarette aerosols, but further study is needed.

Toilet plume aerosol generation rate and environmental contamination following bowl water inoculation with Clostridium difficile spores.

INTRODUCTION: Clostridium difficile is the leading cause of health care-associated gastric illness. Environmental contamination with C difficile spores is a risk factor for contact transmission, and toilet flushing causes such contamination. This work explores toilet contamination persistence and environmental contamination produced over a series of flushes after contamination. METHODS: A flushometer toilet was seeded with C difficile spores in a sealed chamber. The toilet was flushed 24times, with postflush bowl water samples and settle plates periodically collected for culturing and counting. Air samples were collected after each of 12 flushes using rotating plate impactors. RESULTS: Spores were present in bowl water even after 24 flushes. Large droplet spore deposition accumulated over the 24-flush period. Droplet nuclei spore bioaerosol was produced over at least 12 flushes. CONCLUSIONS: Toilets contaminated with C difficile spores are a persistent source of environmental contamination over an extended number of flushes.

Electronic cigarette power affects count concentration and particle size distribution of vaping aerosol.

INTRODUCTION: Electronic cigarettes (EC) have evolved rapidly toward higher powered devices that produce more vaping aerosol and a more satisfying vaping experience. This research characterized the particle size distribution and estimated the mass concentration of vaping aerosols produced at power outputs spanning the operating range typical of second generation variable voltage EC devices. METHODS: EC aerosol was characterized from a single coil atomizer powered by a variable voltage EC battery at the minimum and maximum dial settings (3.3, 11.2 Watts, W), and a lab controlled power supply (3-11.9 W). Aerosol particle size distribution was measured by a Scanning Mobility Particle Sizer and Aerodynamic Particle Sizer, spanning 16 nm to 19.8 µm. A mouth puff was simulated using a 100 mL glass syringe. RESULTS: Consistent with prior studies, sub-micron EC aerosol size distributions were bimodal, with peaks at 40 and 200 nm, however a previously unreported third mode was observed at approximately 1000 nm. The ~1000 nm mode accounted for 7-20x the aerosol mass of the smaller modes. Increasing atomizer power decreased count concentration of particles <600 nm but increased particle count >600 nm. Particle mass distribution shifted toward micron sized particles with increasing power and increased the respirable fraction of aerosol, likely due to increased coagulation and condensation around nano-sized particles. CONCLUSIONS: Vaping power greatly affects EC aerosol count and mass distribution. Mouth puffed EC aerosol spans a much wider particle size range than previously reported, although the major portion of the mass is still well within the alveolar size range the larger particles will deposit within the oro-pharyngeal cavity at 2-3x greater efficiency than in alveoli. These observations have major clinical implications, as aerosol particle size distribution determines deposition sites along the respiratory tract. The results of this experiment stress the need for further research to inform the design, regulation and use of e-cigarette products.

Influence of facial hair length, coarseness, and areal density on seal leakage of a tight-fitting half-face respirator.

BACKGROUND: OSHA regulations state that an employer shall not permit tight-fitting respirators to be worn by employees who have facial hair that comes between the skin and facepiece seal. Studies have shown that facial hair in the face seal zone can increase penetration and decrease the fit factor (FF), although the relationship between the amount and characteristics of facial hair and the increase in penetration is not well quantified. This article examines the influence of facial hair length, areal density, and coarseness on FF for one model of half-face elastomeric negative-pressure air purifying respirator. APPROACH: Quantitative fit tests (QNFT) were performed on 19 subjects with beards initially 0.500-in long and subsequently trimmed to 0.250, 0.125, and 0.063 in, then after a razor shave. Three fit tests were performed at each of the 5 lengths, for 285 total tests. The average diameter and areal density of cheek and chin hair were measured. Penetration was modeled as a function of hair length category, beard areal density, and hair coarseness. RESULTS: FF decreased with beard length, especially beyond 0.125 in. However, passing FF scores were achieved on all tests by all subjects at the smooth shave and 0.063 in conditions, and 98% of tests were passed at 0.125 in; seven subjects passed all tests at all conditions. Chin and cheek areal densities were significantly different and were only weakly correlated. Beard hair diameters were normally distributed across subjects (mean 76 µm, standard deviation 7.4 µm). Beard length and areal density, but not coarseness, were statistically significant predictors of fit using an arcsine transformed penetration model. FF decreased with increasing beard length, especially beyond 0.125 in, although FF with a "stubble" beard did not differ significantly from a smooth shave. FF also decreased with increasing areal beard hair density. CONCLUSION: Beard length and areal density negatively influence FF. However, tight-fitting half-face negative-pressure respirator fit tests can achieve adequate fit factor scores even with substantial facial hair in the face seal area.

Experimental Evaluation of Respirable Dust and Crystalline Silica Controls During Simulated Performance of Stone Countertop Fabrication Tasks With Powered Hand Tools.

OBJECTIVES: Workers who fabricate stone countertops using hand tools are at risk of silicosis from overexposure to respirable crystalline silica. This study explored the efficacy of simple engineering controls that can be used for dust suppression during use of hand tools by stone countertop fabricators. METHODS: Controlled experiments were conducted to measure whether wet methods and on-tool local exhaust ventilation (LEV) reduced respirable dust (RD) exposures during use of various powered hand tools on quartz-rich engineered stone. RD samples collected during edge grinding with a diamond cup wheel and a silicon carbide abrasive wheel were analyzed gravimetrically as well as by X-ray diffraction to determine silica content. A personal optical aerosol monitor was used simultaneously with the RD samples and also for rapid assessment of controls for polishing, blade cutting, and core drilling. RESULTS: On-tool LEV and sheet-flow-wetting were effective in reducing exposures, especially when used in combination. Sheet-flow-wetting with LEV reduced geometric mean exposures by as much as 95%. However, typical water-spray-wetting on a grinding cup was less effective when combined with LEV than without LEV. Mean silica content of RD samples from grinding operations was 53%, and respirable mass and silica mass were very highly correlated (r = 0.980). Optical concentration measures were moderately well correlated with gravimetric measures (r = 0.817), but on average the optical measures during a single trial using the factory calibration were only one-fifth the simultaneous gravimetric measures. CONCLUSIONS: Sheet-flow-wetting combined with on-tool LEV is an effective engineering control for reducing RD exposures during engineered stone edge grinding and blade cutting. On the other hand, addition of LEV to some water-spray-wetted tools may reduce the effectiveness of the wet method.

Persistence of Bowl Water Contamination during Sequential Flushes of Contaminated Toilets.

Toilets contaminated with infectious organisms are a recognized contact disease transmission hazard. Previous studies indicate that toilet bowl water can remain contaminated for several flushes after the contamination occurs. This study characterized contamination persistence over an extended series of flushes using both indicator particles and viable bacteria. For this study, toilets were seeded with microbe-size microbial surrogates and with Pseudomonas fluorescens or Clostridium difficile bacteria and flushed up to 24 times. Bowl water samples collected after seeding and after each flush indicated the clearance per flush and residual bowl water contaminant concentration. Toilets exhibited 3 + log10 contaminant reductions with the first flush, only 1-2 logs with the second flush, and less than 1 log thereafter. Contamination still was present 24 flushes post contamination. Clearance was modeled accurately by a two-stage exponential decay process. This study shows that toilet bowl water will remain contaminated many flushes after initial contamination, posing a risk of recurring environmental contamination and associated infection incidence.

Respirable silica dust suppression during artificial stone countertop cutting.

PURPOSE: To assess the relative efficacy of three types of controls in reducing respirable silica exposure during artificial stone countertop cutting with a handheld circular saw. APPROACH: A handheld worm drive circular saw equipped with a diamond segmented blade was fitted with water supply to wet the blade as is typical. The normal wetted-blade condition was compared to (i) wetted-blade plus 'water curtain' spray and (ii) wetted-blade plus local exhaust ventilation (LEV). Four replicate 30-min trials of 6-mm deep, 3-mm wide cuts in artificial quartz countertop stone were conducted at each condition in a 24-m(3) unventilated tent. One dry cutting trial was also conducted for comparison. Respirable cyclone breathing zone samples were collected on the saw operator and analyzed gravimetrically for respirable mass and by X-ray diffraction for respirable quartz mass. RESULTS: Mean quartz content of the respirable dust was 58.5%. The ranges of 30-min mass and quartz task concentrations in mg m(-3) were as follows-wet blade alone: 3.54-7.51 and 1.87-4.85; wet blade + curtain: 1.81-5.97 and 0.92-3.41; and wet blade + LEV: 0.20-0.69 and <0.12-0.20. Dry cutting task concentrations were 69.6 mg m(-3) mass and 44.6 mg m(-3) quartz. There was a statistically significant difference (α = 0.05) between the wet blade + LEV and wet blade only conditions, but not between the wet blade + curtain and wet blade only conditions, for both respirable dust and respirable silica. CONCLUSIONS: Sawing with a wetted blade plus LEV reduced mean respirable dust and quartz task exposures by a factor of 10 compared to the wet blade only condition. We were unable to show a statistically significant benefit of a water curtain in the ejection path, but the data suggested some respirable dust suppression.

Stress-dependent normal-mode frequencies from the effective mass of granular matter.

A zero-temperature critical point has been invoked to control the anomalous behavior of granular matter as it approaches jamming or mechanical arrest. Criticality manifests itself in an anomalous spectrum of low-frequency normal modes and scaling behavior near the jamming transition. The critical point may explain the peculiar mechanical properties of dissimilar systems such as glasses and granular materials. Here we study the critical scenario via an experimental measurement of the normal modes frequencies of granular matter under stress from a pole decomposition analysis of the effective mass. We extract a complex-valued characteristic frequency which displays scaling |ω (σ)| ∼ σΩ' with vanishing stress σ for a variety of granular systems. The critical exponent is smaller than that predicted by mean-field theory opening new challenges to explain the exponent for frictional and dissipative granular matter. Our results shed light on the anomalous behavior of stress-dependent acoustics and attenuation in granular materials near the jamming transition.

Small-amplitude acoustics in bulk granular media.

We propose and validate a three-dimensional continuum modeling approach that predicts small-amplitude acoustic behavior of dense-packed granular media. The model is obtained through a joint experimental and finite-element study focused on the benchmark example of a vibrated container of grains. Using a three-parameter linear viscoelastic constitutive relation, our continuum model is shown to quantitatively predict the effective mass spectra in this geometry, even as geometric parameters for the environment are varied. Further, the model's predictions for the surface displacement field are validated mode-by-mode against experiment. A primary observation is the importance of the boundary condition between grains and the quasirigid walls.

Determinants of respirable silica exposure in stone countertop fabrication: a preliminary study.

A preliminary study of personal exposure to respirable quartz was conducted in four shops that used a variety of wet and dry methods to fabricate countertops from granite and quartz-containing synthetic stone-like materials. Full-shift time-weighted average (TWA) exposures exceeded the ACGIH threshold limit value of 0.025 mg/m(3) for all workers who used dry fabrication methods, even for very limited time, during any part of the work shift (n = 15 person-days). The geometric mean of exposures for workers who used dry methods extensively was about 1 mg/m(3) (n = 12 person-days). Workers who operated only automated or remotely controlled stone cutting or shaping equipment had calculated TWA exposures of approximately 0.02 mg/m(3) (n = 3 person-days). Task-specific geometric mean exposures for various wet and dry manual operations were ranked based on estimated concentrations extracted from multi-task partial-shift sample results using a linear algebra procedure. Limited use of dry methods was observed in shops that had previously reported using only wet methods. These results suggest that even shops that report using only wet methods might, in fact, resort to brief use of dry methods for specific operations. Therefore, there may be reason for concern over potential overexposure to respirable quartz in all stone countertop shops.

Increasing time between first diagnosis of atrial fibrillation and catheter ablation adversely affects long-term outcomes.

BACKGROUND: Many patients who develop atrial fibrillation (AF) will experience a worsening of their arrhythmia over time. The optimal time to proceed with catheter ablation during the disease course is unknown. Further, whether delays in treatment will negatively influence outcomes is unknown. OBJECTIVE: The purpose of this study was to examine the impact of delay in treatment after the first clinical diagnosis of AF on ablation-related outcomes. METHODS: A total of 4535 consecutive patients who underwent an AF ablation procedure that had long-term established care within an integrated health care system were evaluated. Recursive partitioning was used to determine categories associated with changes in risk from the time of first AF diagnosis to first AF ablation: 1: 30-180 (n = 1152), 2: 181-545 (n = 856), 3: 546-1825 (n = 1326), and 4: >1825 (n = 1201) days. Outcomes evaluated include 1-year AF recurrence, stroke, heart failure hospitalization, and death. RESULTS: With increasing time to treatment, surprisingly patients were older (1: 63.7 ± 11.1, 2: 62.6 ± 11.8, 3: 66.4 ± 10.2, 4: 67.6 ± 9.7; P <.0001) and had more hypertension (1: 53.0%, 2: 59.0%, 3: 53.8%, 4: 39.0%; P <.0001). For each strata of time increase, there was a direct increase of 1-year AF recurrence (1: 19.4%, 2: 23.4%, 3: 24.9%, 4: 24.0%: P trend = .02). After adjustment, clinically significant differences in risk of recurrent AF were found when compared to the 30-180 day time category: 181-545: odds ratio (OR) = 1.23, P = .08; 546-1825: OR = 1.27, P = .02; and >1825: OR = 1.25, P = .05. No differences were observed for 1-year stroke among the groups. Death (1: 2.1%, 2: 3.9%, 3: 5.7%, 4: 4.4%: P trend = .001) and heart failure hospitalization (1: 2.6%, 2: 4.1%, 3: 5.4%, 4: 4.4%; P trend = .009) rates at 1 year were higher in the most delayed groups. CONCLUSION: Delays in treatment with catheter ablation impact procedural success rates independent of temporal changes to the AF subtype at ablation.

Intracardiac ultrasound for esophageal anatomic assessment and localization during left atrial ablation for atrial fibrillation.

BACKGROUND: Esophageal injury during left atrial ablation is associated with a significant risk of mortality and morbidity. There are no validated approaches to reduce injury outside of avoidance, a strategy critically dependent on a precise understanding of the esophageal anatomy and location. Intracardiac ultrasound (ICE) can provide a real-time assessment of the esophagus during ablation. We hypothesized that ICE can accurately define esophageal anatomy and location to enhance avoidance strategies during ablation. METHODS: Fifty patients underwent atrial fibrillation (AF) ablation. The left atrium and pulmonary vein anatomies were rendered by traditional electroanatomic mapping (CARTO). A Navistar catheter within the esophagus was used to create a traditional electroanatomic esophageal anatomy. ICE imaging was used to create a second geometry of the esophagus. The traditional and ICE anatomies of the esophagus were compared and the greatest border dimensions used to avoid injury. RESULTS: The average age was 66 ± 10 years, 45% had persistent/longstanding persistent AF, and 18% had a prior AF ablation. The esophagus location was leftward in 17 (34%), midline in 22 (44%), and rightward in 11 (22%). Traditional esophagus and ICE imaging correlated within 1 cm in the greatest distance in 26 (52%) patients. Traditional imaging underestimated the esophageal location by >1-1.5 cm in 9 (18%) and >1.5 cm in 15 (30%). In those with poor correlation (>1.5 cm), the most common cause was the presence of a hiatal hernia. Ablation energy delivery was performed outside the greatest esophagus anatomy borders. Of those with 12-month follow-up, 75% were AF/atrial flutter free without antiarrhythmic drugs. No esophageal injuries were observed. One patient experienced a TIA greater than 6 months postablation. CONCLUSION: These data demonstrate that traditional means of mapping the esophagus using a catheter within the esophagus are insufficient and often grossly underestimate the actual anatomy. Imaging techniques that define the complete esophageal lumen should be considered to truly minimize esophageal injury risk.

Lifting the lid on toilet plume aerosol: a literature review with suggestions for future research.

BACKGROUND: The potential risks associated with "toilet plume" aerosols produced by flush toilets is a subject of continuing study. This review examines the evidence regarding toilet plume bioaerosol generation and infectious disease transmission. METHODS: The peer-reviewed scientific literature was searched to identify articles related to aerosol production during toilet flushing, as well as epidemiologic studies examining the potential role of toilets in infectious disease outbreaks. RESULTS: The studies demonstrate that potentially infectious aerosols may be produced in substantial quantities during flushing. Aerosolization can continue through multiple flushes to expose subsequent toilet users. Some of the aerosols desiccate to become droplet nuclei and remain adrift in the air currents. However, no studies have yet clearly demonstrated or refuted toilet plume-related disease transmission, and the significance of the risk remains largely uncharacterized. CONCLUSION: Research suggests that toilet plume could play a contributory role in the transmission of infectious diseases. Additional research in multiple areas is warranted to assess the risks posed by toilet plume, especially within health care facilities.

Atrial fibrillation and atrial flutter: nonpharmacologic therapy.

As elderly patients present significant challenges for long-term pharmacologic management, nonpharmacologic treatment of atrial fibrillation (AF) will continue to be a vital option in improving the quality of life and function of these patients. This review discusses nonpharmacologic approaches for AF in the elderly. Observational studies of catheter ablation suggest similar long-term efficacy and safety rates in elderly and younger groups. Minimally invasive surgical approaches have distinct advantages in certain populations. Further research, adequately powered to assess age-related differences, is needed to confirm the findings of observational studies of elderly patients who have undergone nonpharmacologic approaches to rhythm control.

Suspension and resuspension of dry soil indoors following track-in on footwear.

Contamination of the indoor environment by tracked-in outdoor soil has the potential to pose a significant human health threat through exposure to hazardous soil constituents. The indoor distribution of (contaminated) soil following ingress is important when evaluating exposure risk. Here, the time evolution of size-resolved airborne particulate matter aerosolized as a result of mechanical (i.e., footfall or step-on) impacts on a floor surface with a layer of dry soil was investigated using laser particle counters. Suspended particle levels were recorded after step-on impacts that aerosolized soil particles at a single contact point by the action of a human tester who followed a pre-determined walking pattern. The experimental design presumed that the floor area immediately upon entrance indoors is the location of maximum deposition of outdoor soil transferred on footwear. The suspension of soil resulting from the first step-on floor contact and the subsequent resuspension of soil resulting from additional step-on events were quantified by various arrangements of four laser particle counters. Step-on impacts produced a transient increase in particle levels at various lateral distances and heights from the contact point. Also, with increasing distance and height from the step-on contact point, the level of suspended particles after successive step-on events decreased markedly. The results suggested that a lateral component of the dispersion process was more significant than a vertical one under these experimental conditions. A wall jet effect created by the impact of the footfalls on the floor surface was considered responsible for the apparent greater lateral dispersion of the soil particles.